JP2000293067A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably secure an excellent image state without dispersion by restraining the dispersion of the image state in a recording body carrying direction. SOLUTION: When fixing test images TA to TC are formed on the recording body (S1), a supervisory control part reads test image data (S3) and calculates toner requirement adhesion amount from the test image data obtained at S3 (S4). When an image information detection part detects the intensity 1b (IbA to IbC) of the regularly reflected light of the images TA to TC and the emitted light intensity 1a (IaA to IaC) of a halogen lamp, the measured glossiness of the images TA to TC is calculated by using the detected intensity (S5). Furthermore, the real adhesive amount of toner adhering to the images TA to TC is estimated based on the surface temperature (fixing temperature) of a heating roller and each measured glossiness calculated at S5 (S6). Then, a charge voltage value is corrected so that the proper amount of toner may adhere to the recording body S without dispersion (S7 to S12).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile. More specifically, the present invention relates to an image forming apparatus capable of stably obtaining a fixed image in which a good image state is secured.

[0002]

2. Description of the Related Art For example, in an image forming apparatus such as an electrophotographic copying machine, a permanent image is obtained by fixing a toner image transferred to a recording medium. Here, as a fixing method, there are methods such as heat fixing, pressure fixing, and solvent fixing. Among them, a heat roller type fixing device using heat fixing is widely and generally used. As this fixing device, for example, a fixing device including a heating roller and a pressure roller is known. The heating roller is a metal roller having good heat conduction and small heat capacity. The heating roller has a heater lamp inside, and the surface temperature is detected by a thermistor or the like, and the temperature is controlled so as to be within a predetermined fixing temperature range. On the other hand, the pressing roller has a core material whose surface is coated with elastic silicon rubber or the like. The heating roller and the pressure roller are rotatably supported in a state where they are pressed against each other. When the recording material on which the toner image is transferred passes between the heating roller and the pressure roller, the toner melts. At the same time, the toner image is pressed against the recording medium to fix the toner image, thereby obtaining a permanent image. In the fixing device provided in the color image forming apparatus, the surface of the heating roller is also covered with silicone rubber.

Here, when thick paper or an OHP sheet having a large heat capacity is used as a recording medium, if fixing is performed under the same conditions as plain paper, the toner does not sufficiently melt, which may result in poor fixing. There is. For this reason, a good image state is ensured by increasing the fixing temperature or decreasing the fixing speed to supply a larger amount of heat than that supplied to plain paper.

[0004]

However, in the conventional apparatus, it was not possible to detect the quality of the image of the fixed image fixed on the recording medium. The quality of the image condition was not understood. Therefore, for example, if an abnormality occurs in the temperature control of the heating roller or the control of the number of rotations of the roller, the unfixed image cannot be appropriately fixed on the recording medium, and the toner may not be properly melted or may be melted due to overmelting. There is a possibility that a fixed image in which a favorable image state is secured cannot be obtained. That is, when the toner is insufficiently melted, there is a problem that the gloss of the image is too low with plain paper or thick paper, and a satisfactory image state cannot be secured because sufficient translucency of the image cannot be secured with the OHP sheet. Was. Conversely, when the toner is excessively melted, there is a problem that the gloss of the image becomes too high with plain paper or thick paper, and a good image state cannot be secured.

In addition, if there are variations in fixing conditions and image forming conditions such as variations in the temperature of the heating roller in the axial direction (temperature distribution) and variations in the distance between the rollers in the axial direction, for example,
When the image state of the fixed image partially fluctuates and a good image state and a poor image state are formed in the fixed image formed on one recording medium, and a uniform image state cannot be obtained. There was also. However, there has been no image forming apparatus that improves the non-uniform image state when the image state varies in a direction perpendicular to the recording medium conveyance direction.

When a large number of copies are made at one time, it is troublesome to check the quality of an image one by one, so it is generally performed after all copies are completed. . Further, when the OHP sheet was used as the recording medium, the quality of the image state was not known until the actual translucent image was visually recognized by the projector. For this reason, when the image after copying is visually recognized, if the image state is defective, a lot of time must be spent to make a copy again, or an unsatisfactory OHP sheet must be used. Had also occurred.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is possible to suppress variations in the image state in the recording medium conveyance direction, thereby ensuring a stable and good image state without variation. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0008]

According to the image forming apparatus of the present invention which has been made to solve the above problems, there is provided an image forming means for forming an unfixed image on a recording medium based on image data; An image forming apparatus comprising: a contact heating fixing unit that fixes an unfixed image created by the image creating unit on the recording medium by contact heating, wherein one of the image creating unit and the contact heating fixing unit includes an image. An image forming process condition changing unit capable of changing at least one or more of the process conditions of the forming process in a direction orthogonal to the recording medium conveying direction; and fixing the image on the recording medium by the contact heating fixing unit. A light emitting element for irradiating the fixed image with light, and a light receiving element for detecting intensity information of light emitted from the light emitting element and reflected or transmitted through the fixed image Image information detecting means for detecting image information of the fixed image at least at two or more locations of the recording body in a direction orthogonal to the recording medium transport direction; and detecting the image information by the image information detecting means. From the result, the variation regarding the image information of each fixed image is calculated,
Image forming process condition correcting means for correcting the process conditions in the image forming process condition changing means based on the variation.

In this image forming apparatus, first, an image forming means forms an unfixed image (toner image) on a recording medium. Here, the unfixed image created on the recording medium by the image creating means includes not only a copy image of a document to be copied, image data input to the image forming apparatus, but also pre-stored in the image forming apparatus. A predetermined test image based on the test image data is also included. Next, the contact heating fixing unit fixes the unfixed image created by the image creating unit on the recording medium. When the fixing is completed, the image information detecting means detects the image information of the fixed image at at least two or more places in the recording medium having different positions in the direction orthogonal to the recording medium conveyance direction.

The detection of image information is performed by irradiating a fixed image on a recording medium with light by a light emitting element and receiving light reflected or transmitted through the fixed image by a light receiving element. Here, the image information refers to information related to the state of the image, such as the surface state, translucency, and coloring, for example, and includes any information as long as the image state can be known.
Specifically, the intensity (transmittance) of the transmitted light of the fixed image, the intensity (reflectance) of the reflected light, or a color shift (a shift of lightness, hue, and saturation) are exemplified.

Subsequently, the image forming process condition correcting means includes:
A change in the image information of the fixed image is calculated from the detection result of the image information detecting means, and the process condition in the image forming process condition changing means is corrected based on the calculated change.
By this correction, for example, the calculation results are reflected (developed) in the development conditions and the transfer conditions so as to suppress variations in the image state in a direction perpendicular to the recording medium conveyance direction in one recording body, thereby automatically performing the calculation. It is possible to control so as to obtain an excellent fixed image. Therefore, it is possible to obtain a fixed image in which a good image state is stably secured.

The image forming process conditions refer to various process conditions until a fixed image is formed on a recording medium, and specifically include, for example, development conditions and transfer conditions. In addition to plain paper, thick paper and O
Any material that can fix an image, such as an HP sheet or special paper coated with a resin, may be used. Further, any light emitting element may be used as long as it emits light in the visible light region. For example, a halogen lamp, a light emitting diode, a semiconductor laser, and the like can be given. Further, the light receiving element may be any element having a sensitivity range that responds to light emitted from the light emitting element. For example, a CCD, a photodiode, and the like can be given.

Here, in order to obtain the reflectance and the transmittance, the intensity of the incident light is necessary in addition to the intensity of the reflected light or the transmitted light. Therefore, the intensity of the incident light may be separately detected in addition to the reflected light or the transmitted light. However, when the intensity of the incident light is known, such as when the intensity is constant, the evaluation can be performed only with the intensity of the reflected light or the transmitted light. In addition, in the measurement of the intensity of the incident light, a method of directly measuring the intensity using a half mirror or the like, and a method of indirectly measuring the applied voltage, the current consumption, the power consumption, and the like of the light emitting element can also be used. .

Further, in the image forming apparatus according to the present invention, there is provided a fixing temperature detecting means for detecting a fixing temperature in the contact heating fixing means, wherein the image forming process condition correcting means comprises the image information and the fixing temperature. And a detection area image corresponding to a detection area of the image information detection means in the image data. A required developer amount calculating unit for calculating a required developer amount originally required for creating the fixed image based on the data, and the fixing is performed based on the realized image agent amount and the required developer amount. A change in the amount of developer in the image is calculated, and the process condition in the image forming process condition changing means is corrected based on the change.

In this image forming apparatus, the realized image agent amount estimating means of the image forming process condition correcting means is based on the plurality of image information detected by the image information detecting means and the fixing temperature detected by the fixing temperature detecting means. Thus, the realized image agent amount of the fixed image is estimated. Further, the required developer amount calculating means calculates the required developer amount of the fixed image based on the detection area image data (for example, density data or the like). Then, a variation regarding the developer amount of the fixed image is calculated from the realized image agent amount and the required developer amount, and the process condition in the image forming process condition changing means is corrected based on the variation. More specifically, for example, the actual image agent amount is compared with the required developer amount, and the processing result is reflected (feedback) on the development conditions, transfer conditions, and the like. As a result, the realized image amount of the fixed image is brought close to the required amount of the developer, and a good fixed image is obtained in which the variation in the image state in the direction perpendicular to the recording medium conveyance direction in one recording medium is automatically suppressed. Can be controlled so that
Therefore, the developer adheres uniformly on the recording medium in a direction orthogonal to the recording medium conveyance direction, so that a fixed image in which a good image state is secured can be obtained.

Further, in the image forming apparatus according to the present invention, there is provided a fixing temperature detecting means for detecting a fixing temperature in the contact heating fixing means, wherein the image forming process condition correcting means comprises the detecting area image data and the fixing area. Request image information calculating means for calculating required image information to be originally obtained based on the temperature; calculating a change in the image information of the fixed image from the image information and the requested image information; Thus, the process conditions in the image forming process condition changing means are corrected.

In this image forming apparatus, the required image information calculating means of the image forming process condition correcting means is based on the image information detected by the image information detecting means and the fixing temperature detected by the fixing temperature detecting means. The required image information to be obtained is calculated. Then, a change in the image information of the fixed image is calculated from the actually measured image information and the requested image information, and the process condition in the image forming process condition changing means is corrected based on the change. Specifically, for example,
The measured image information is compared with the requested image information, and the processing result is reflected (feedback) on the development conditions, transfer conditions, and the like. As a result, the image information of the fixed image is brought close to the required image information, and a good fixed image is obtained in which the variation in the image state in the direction perpendicular to the recording medium conveyance direction in one recording medium is automatically suppressed. Since control can be performed, a fixed image in which a favorable image state is secured can be obtained.

Further, in the image forming apparatus according to the present invention, the image forming process condition varying means includes a plurality of chargers for applying a charge to the photoreceptor in a direction orthogonal to the recording medium conveying direction, and the plurality of chargers. The image forming process condition correcting means is a charging condition correcting means for correcting the charging condition of each charger.

In this image forming apparatus, the image information detecting means detects the image information of the fixed image at at least two or more places in the recording medium where the positions in the direction perpendicular to the recording medium conveyance direction are different. Then, the image forming process condition correcting means calculates a variation regarding the image information in the direction orthogonal to the recording medium conveying direction of the fixed image from the detection result by the image information detecting means. The calculation of the variation is performed, for example, by comparing the image information at each measurement point, or by comparing the image information at each measurement point with a reference value (required developer amount, required image information, and the like). Then, the charging condition correcting means corrects the charging condition of each charger in the divided charging means based on the fluctuation. By this correction, the calculation result is reflected (feedback) in the power failure condition so that the image state is improved, that is, the variation of the image state in the direction perpendicular to the recording medium conveyance direction in one recording medium is suppressed. Thus, it is possible to automatically control a good fixed image. Therefore, it is possible to obtain a fixed image in which a good image state is stably secured.

Further, in the image forming apparatus according to the present invention, the image forming process condition changing means may move the developer carrier for supplying the developer to the electrostatic latent image on the photosensitive member in a direction perpendicular to the recording medium conveying direction. A developing bias voltage to be applied to each of the plurality of developer carrying members; and a developing bias voltage value to be applied to each of the plurality of developer carrying members. This is a developing condition correcting means for correcting a value.

In this image forming apparatus, the image information detecting means detects the image information of the fixed image at least at two or more places in the recording medium where the positions in the direction orthogonal to the recording medium conveyance direction are different. Then, the image forming process condition correcting means calculates a variation regarding the image information in the direction orthogonal to the recording medium conveying direction of the fixed image from the detection result by the image information detecting means. The calculation of the variation is performed, for example, by comparing the image information at each measurement point, or by comparing the image information at each measurement point with a reference value (required developer amount, required image information, and the like). Then, the developing condition correcting means corrects the developing bias voltage value applied to the developer carrier provided in each developing device in the divided developing means based on the fluctuation. By this correction, for example, the calculation result is reflected (feedback) in the developing bias voltage value so that the image state is improved, that is, the fluctuation of the image state in the direction orthogonal to the recording medium conveyance direction in one recording medium is suppressed. ), It is possible to automatically control to obtain a good fixed image. Therefore, it is possible to obtain a fixed image in which a good image state is stably secured.

In the image forming apparatus according to the present invention, the image forming process condition changing means may include a plurality of transfer devices for transferring a visible image on a photosensitive member onto the recording material in a direction perpendicular to the recording material conveying direction. The image forming process condition correcting means includes a transfer current and a transfer voltage in each of the plurality of transfer devices. This is a transfer condition correcting means for correcting.

In this image forming apparatus, the image information detecting means detects the image information of the fixed image in at least two or more places in the recording medium where the positions in the direction orthogonal to the recording medium conveyance direction are different. Then, the image forming process condition correcting means calculates a variation regarding the image information in the direction orthogonal to the recording medium conveying direction of the fixed image from the detection result by the image information detecting means. The calculation of the variation is performed, for example, by comparing the image information at each measurement point, or by comparing the image information at each measurement point with a reference value (required developer amount, required image information, and the like). Then, the transfer condition correction means corrects one of the transfer current and the transfer voltage of each transfer device in the divided transfer means based on the fluctuation. This correction improves the image condition, that is, 1
The calculation result is reflected (feedback) to the transfer current or the transfer voltage so that the variation in the image state in the direction perpendicular to the recording medium conveyance direction in the recording medium is suppressed, so that a good fixed image is automatically obtained. Can be controlled so that Therefore, it is possible to obtain a fixed image in which a good image state is stably secured.

Further, in the image forming apparatus according to the present invention, the image forming process condition changing means includes a plurality of the heaters in a direction orthogonal to the recording medium conveying direction and changes control temperatures of the plurality of heaters. The image forming process condition correcting means is a fixing temperature correcting means for correcting a control temperature of each heater.

In this image forming apparatus, the image information detecting means detects the image information of the fixed image at at least two or more places in the recording medium where the positions in the direction orthogonal to the recording medium conveyance direction are different. Then, the image forming process condition correcting means calculates a variation regarding the image information in the direction orthogonal to the recording medium conveying direction of the fixed image from the detection result by the image information detecting means. The calculation of the variation is performed, for example, by comparing the image information at each measurement point, or by comparing the image information at each measurement point with a reference value (required developer amount, required image information, and the like). Then, the fixing temperature correction unit corrects the control temperature of each heater in the divided heating unit based on the fluctuation. This correction reflects (feeds back) the calculation result on the fixing temperature so that the image state is improved by the correction, that is, the variation in the image state in the direction perpendicular to the recording medium conveyance direction in one recording medium is suppressed. Thus, control can be performed so that a good fixed image is automatically obtained. Therefore, it is possible to obtain a fixed image in which a good image state is stably secured.

According to the image forming apparatus of the present invention, there is provided an image forming means for forming an unfixed image on a recording medium,
A fixing unit for fixing an unfixed image created by the image creating unit on the recording medium, wherein the light emitting element irradiates light to the fixed image fixed on the recording body by the fixing unit. And a light receiving element for detecting intensity information of light emitted from the light emitting element and reflected or transmitted through the fixed image, and wherein at least two or more of the fixing members of the recording material, the positions of which in the recording material conveyance direction are different. Image information detecting means for detecting image information of an image, calculating a change in image information of each of the fixed images from a detection result by the image information detecting means, and from the image creating means to the fixing means based on the change. And a charging time interval correcting means for correcting a charging time interval for charging the recording medium.

In this image forming apparatus, first, the image forming means forms an unfixed image (toner image) on a recording medium. Here, the unfixed image created on the recording medium by the image creating means includes not only a copy image of a document to be copied, image data input to the image forming apparatus, but also pre-stored in the image forming apparatus. A predetermined test image based on the test image data is also included. Next, the fixing unit fixes the unfixed image created by the image creating unit on the recording medium. When the fixing is completed, the image information detecting means detects the image information of the fixed image at at least two or more places in the recording medium having different positions in the direction orthogonal to the recording medium conveyance direction. The detection of the image information is performed by irradiating the fixed image on the recording medium with light by the light emitting element and receiving light reflected or transmitted through the fixed image by the light receiving element.

Then, the throwing time interval correcting means calculates a variation relating to the image information of the fixed image from the detection result by the image information detecting means. The calculation of the variation is performed, for example, by comparing image information at each measurement point, or by comparing a reference value (required image information or the like) at each measurement point. Then, the input time interval correcting means corrects the input time interval for inputting the recording medium from the image creating means to the fixing means based on the fluctuation. Specifically, for example, when the input time interval correction unit corrects the conveyance speed of the recording medium in the image forming unit, or when the image forming unit has a transfer drum or a transfer belt that can hold a plurality of recording materials at the same time, , The number of recording media held by them is corrected.

By such correction of the charging time interval, the fixing conditions in the fixing means can be adjusted to appropriate conditions before the next fixing. As a result, the fixing can always be performed at an appropriate fixing temperature, so that the image state is improved. That is, for example, when using a recording medium (thick paper, OHP sheet, etc.) that takes a large amount of heat from the fixing unit due to a large heat capacity, even if the image state is good at the leading end of the recording medium, the amount of heat applied to the fixing unit is small. In some cases, the supply temperature does not catch up, the fixing temperature gradually decreases, and the image state deteriorates at the rear end of the recording medium. In the next fixing operation, the image state may further deteriorate. However, by correcting the charging time interval as described above, appropriate fixing conditions are set by the time the next fixing operation is performed. Fixing can be performed at the earliest possible time interval while maintaining. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured.

Further, in the image forming apparatus according to the present invention, the image forming means has a test image data memory for storing test image data for forming a predetermined test image on the recording medium, The information detecting means includes:
It is possible to detect intensity information of light transmitted or reflected by the fixing test image fixed on the recording medium.

By using the fixing test image obtained from the previously stored test image data, the position of the fixed image whose image information is to be measured is known in advance. It is possible to reliably obtain image information on a fixed image. Therefore, it is possible to reliably determine whether the image state is good or not and the variation in the image state in one recording medium, and reflect the processing result of the image information on the obtained test image in the fixing condition, the image forming condition, and the like. As a result, the image state can be improved, and variations in the image state can be suppressed. Further, by performing a process of comparing the obtained image information with ideal image information expected from the test image data (that is, originally expected), it is possible to easily and accurately determine whether the image state is good or not and its variation. Or fixing conditions.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of an image forming apparatus according to the present invention will be described in detail with reference to the drawings. First, the first embodiment will be described. The first embodiment is an electrophotographic copying machine in which the image forming apparatus according to the present invention is mounted. This is to correct the charging condition of the charging charger that applies a charge to the photosensitive drum based on the charging condition.

As shown in FIG. 1, the copying machine 1 includes an image reader section IR and a page printer section PRT. Then, based on the image data transferred from the image reader section IR, the page printer section PRT prints the image of the document by an electrophotographic process.

The image reader section IR includes an original glass 10
An image reading unit 2 that detects reflected light from an image of a document set thereon, photoelectrically converts the reflected light, and reads image data corresponding to the image of the document, and an image that performs data processing according to various image forming modes. And a processing unit 3. Note that the image reading section 2 includes a data memory section 9 for temporarily storing the read image data. A document cover 11 for holding a document is mounted above the image reader IR.

On the other hand, the page printer section PRT has an optical scanning section 4, an image processing section 5, and a transport section 6.
The optical scanning section 4 includes a polygon mirror 21 and a reflection mirror 22 for scanning and irradiating the photosensitive drum 30 with laser light. The image processing unit 5 includes a photosensitive drum 30, a charging charger 31, and developing units 32Y and 3
2C, 32M, 32K, a transfer drum 34 having a transfer charger 33, and a cleaning device 35. The transport unit 6 includes a paper cassette 44 for stacking and storing the recording medium.
And various transport rollers for transporting the recording medium supplied from the paper cassette 44 or the manual feed tray 45; a fixing device 40; an image information detecting unit 43 including a halogen lamp 41 and a CCD sensor 42; And a paper discharge tray 46 for accommodating the recording medium discharged outside the apparatus.

As shown in FIG. 2, the charging charger 31 includes three charging chargers, that is, a first charging charger 31A, a second charging charger 31B, and a third charging charger 31C. And FIG.
As shown in FIG. 3, the first charging charger 31A and the third charging charger 31C are provided at the same angular position in the circumferential direction of the photosensitive drum 30, and the second charging charger 31B is connected to the first charging charger 31A and the third charging charger 31.
C is provided at an angular position different from C (an angular position slightly advanced in the rotation direction of the photosensitive drum 30). These chargers 31A to 31C are respectively connected to power supplies 311A to 311A.
311C and charge wires 312A to 312C, and the power supplies 311A to 311C are respectively connected to a high voltage control unit 58 (see FIG. 7) described later. The high-voltage controller 58 allows the first charging charger 31A, the second charging charger 31B, and the third charging charger 31C to apply charges to the surface of the photosensitive drum 30 under different charging conditions. Note that a fixing test image TA (see FIG. 5), which will be described later, is created in a region where the first charging charger 31A applies a charge to the photosensitive drum 30. In a similar relationship, a fixing test image TB is created in an area where the second charging charger 31B applies electric charge to the photosensitive drum 30, and a fixing test image is created in an area where the third charging charger 31C applies electric charge to the photosensitive drum 30. An image TC is created.

The fixing device 40 is composed of a heating roller 212 and a pressure roller 213 arranged vertically, and details thereof will be described with reference to FIG. FIG. 4 shows a cross section of the fixing device 40 in the longitudinal direction. As shown in FIG. 4, the heating roller 212
Silicon rubber 212 is provided on the surface of a metal cylinder 212a made of a material such as aluminum having good heat conduction and small heat capacity.
b. A heater lamp 221 is provided inside the heating roller 212, and is supplied with power and heated based on temperature control by a general control unit 54 (see FIG. 7) described later. The surface temperature of the heating roller 212 is detected by a temperature sensor 222 such as a thermistor provided in contact with the surface. The surface temperature signal detected here is
It is input to the overall control unit 54 described later. On the other hand, similarly to the heating roller 212, the pressing roller 213 has a silicon cylinder 21a in a metal cylinder 213a having a heater lamp 221 therein.
3b.

When the pressure roller 213 is driven by a drive control unit 55 (see FIG. 7), which will be described later, the heating roller 212 also rotates following the pressure roller 213. Note that, instead of the pressing roller 213, the heating roller 212 may be driven by the drive control unit 55, and the pressing roller 213 may be rotated by following the heating roller 212.

The image information detecting section 43 is for detecting image information of the fixed image. Specifically, the glossiness of the fixed image ((specular reflection light quantity / incident light quantity) × 100 =
(Specular reflectance). As shown in FIG. 5, for example, as shown in FIG. 5, the image information detection unit 43 includes three substantially rectangular fixing test images TA, When TB and TC are formed on the recording medium S, the fixing test image TA
And so on so that the intensity of the specularly reflected light can be measured. In other words, the image information detection unit 43 is configured to intersect with the direction in which the recording medium S is conveyed (in this embodiment, the direction orthogonal to the conveyance direction).
, And a set of three light emitting elements and light receiving elements (light emitting / light receiving element pairs).

Specifically, the halogen lamp 41A and the CC
D sensor 42A, halogen lamp 41B and CCD sensor 42B, and halogen lamp 41C and CCD sensor 4
It is composed of three pairs of light emitting / receiving elements 2C. The halogen lamp 41A and the CCD sensor 42A are arranged at positions where the intensity of the reflected light of the fixing test image TA can be measured. That is, in the conveyance path of the recording medium S, behind the fixing device 40, a halogen lamp, which is a light emitting element, is positioned obliquely upper right (diagonally upper in the anti-conveying direction) in FIG. 41A is provided to receive specularly reflected light with respect to the incident light incident on the fixing test image TA from the halogen lamp 41A.
A CCD sensor 42A, which is a light receiving element, is provided on the upper left side (in the transport direction) of FIG. 1 where the incident angle α and the reflection angle β with respect to the fixing test image TA (recording medium S) are equal. In a similar positional relationship, the halogen lamp 41
B, CCD sensor 42B, and halogen lamp 41C
And a CCD sensor 42C. Note that the specularly reflected light (directly reflected light) refers to the incident angle of the incident light incident on the fixed image on the incident surface formed by the incident light and the normal of the fixed image at the incident point in the reflected light. Reflected light that is reflected and travels at the same reflection angle is referred to (in the following description, “specularly reflected light” is used in the same sense).

The pair of halogen lamps 41A and 41A
The CD sensor 42A, the lamp 41B and the sensor 42B, and the lamp 41C and the sensor 42C may be arranged at opposite positions. Further, as shown in FIG. 6, the halogen lamp 41A is so set that the directions of the incident light and the reflected light are orthogonal to the transport direction (leftward behind the fixing device 40 in FIG. 1).
Any arrangement may be used as long as light can be applied to the fixing test image TA and the like and its regular reflected light can be received, such as the arrangement of the CCD sensor 42A and the like.

However, it is desirable that the incident angle α and the reflection angle β are not less than 25 degrees. If the angle is smaller than 25 degrees, the component of the diffused light that wraps around from the periphery becomes large, so that the intensity information of the specularly reflected light cannot be measured accurately, and the arrangement of the halogen lamps 41A to 41C and the CCD sensors 42A to 42C becomes difficult. is there. Further, the incident angle α is more preferably 45 degrees or more. By arranging the halogen lamps 41A to 41C and the CCD sensors 42A to 42C in this way, the fixing test images TA to TC are less susceptible to the influence of the thickness of the fixing test images TA to TC and the lifting of the recording medium S at the time of measurement.
This is because the intensity information of the specularly reflected light can be measured more accurately.

As described above, the halogen lamps 41A to 41C
And the CCD sensors 42A to 42C, the image information detecting unit 43 can detect the glossiness of the regular reflection light (direct reflection light) of the fixing test images TA to TC. That is, the image information detecting unit 43 is provided with the CCD sensor 42A.
To 42C, the intensity IbA to IbC of the reflected light, and the intensity of the incident light (emission intensity) of the halogen lamps 41A to 41C.
By detecting IaA to IaC, the glossiness of the regular reflection light of the fixing test images TA to TC is detected. The glossiness of the specular reflection light is detected because it has a positive correlation with the toner adhesion amount, has a wide detection range, and is strong against noise. In addition, halogen lamps 41A-
The detection of the emission intensities IaA to IaC of 41C includes a method of directly measuring the intensity using a half mirror or the like, and a method of indirectly measuring the applied voltage, current consumption, power consumption, and the like of the light emitting element. Can be

Next, a brief description will be given of an operation when copying is performed in the copying machine 1 configured as described above. In the copying machine 1, the following processing is performed in the order of yellow (Y), cyan (C), magenta (M), and black (K) reproduction colors. First, the processing of yellow (Y) will be described. The image reading unit 2 detects yellow (Y) of the original image
Read the image data corresponding to. In addition, the surface of the photosensitive drum 30 rotating in the direction of the arrow in FIG. 1 is uniformly charged by the charging charger 31.

Then, a laser control unit 59 described later (FIG. 7)
), The image data read by the image reading unit 2 is input. Then, the laser light is modulated and emitted from the laser light source, and this laser light is scanned in the main scanning direction by the polygon mirror 21, further reflected by the reflection mirror 22, and enters the photosensitive drum 30. As a result, an electrostatic latent image corresponding to the reproduced color of yellow (Y) is formed on the photosensitive drum 30. This electrostatic latent image is developed by the developing device 32Y to become a toner image. This toner image is transferred onto a recording medium S supplied from a paper cassette 44 or a manual feed tray 45 by a transfer charger 33 arranged to face the photosensitive drum 30.

Next, cyan (C), magenta (M),
The processing for black (K) is performed similarly. By these processes, the four color toner images are transferred onto the recording medium S in a superimposed manner. Thereafter, the recording material S to which these toner images have been transferred is heated and pressed in the fixing device 40. As a result, the toner is melted, and the toner image is fixed on the recording medium S to form a full-color image. After the image is fixed, the recording medium is discharged out of the apparatus and stored in the paper discharge tray 46. This completes the copying for one sheet.

Here, a control system of the copying machine 1 for controlling such a copying operation and the like will be described. As shown in the block diagram of FIG. 7, the control circuit of the copying machine 1
4 as the center. The general control unit 54 also corresponds to the image forming process condition correcting unit, the realized image agent amount calculating unit, and the required developer amount calculating unit of the present invention. It is a microcomputer configured in combination. Various programs and reference data necessary for executing the control of the copying machine 1 are prepared and stored in the ROM incorporated in the general control unit 54 in advance. Note that test image data for creating a test image, which will be described later, and the like are also stored in the ROM. Further, the RAM is provided with various buffers for temporarily storing numerical values and the like appearing during execution of the arithmetic processing and for reading out the data as needed.

An input / output port of the general control unit 54 includes an IR control unit 51 for controlling the operation of the image reading unit 2 and a fixing unit 4.
A drive control unit 55 for controlling the driving / stopping of the zero and the speed control of the pressure roller 213; a conveyance control unit 56 for controlling the supply of the recording medium; a scanner control unit 57 for controlling the laser beam scanning by the polygon mirror 21; A high-voltage control unit 58 for controlling high voltages such as charging of the photosensitive drum 30, application of a developing bias and a transfer bias, a laser control unit 59 for controlling laser light modulation, an image information detecting unit 43, and a fixing device 4
0 fixing temperature (exactly the surface temperature of the heating roller 212)
Temperature sensor 222 which detects
1 etc. are connected. In addition, the general control unit 54 includes:
A signal is input from the operation panel 53 via the controller 52.

The copying machine 1 is controlled by the overall control unit 54 and operates as follows. First, control information such as the size and type of the recording medium is input from the operation panel 53 to the controller 52. Next, when the copy button on the operation panel 53 is pressed, a copy request signal is transmitted, and this signal is received by the controller 52. Then, a print command is output from the controller 52 to the overall control unit 54. In response to this command, the general control unit 54 instructs the IR control unit 51 to start reading an image of a document, and also instructs the transport control unit 56 to start supplying a recording medium. Scan preparation is instructed. Also, a command is output to the high-voltage control unit 58 and the photosensitive drum 30
, The developing bias and the transfer bias are set, and preparation for image formation is made. When the image reading of the document by the image reading unit 2 is completed, the laser control unit 59
The read image data is input.

Next, the overall control unit 54
2 to output a vertical synchronization request signal and wait for reception of a vertical synchronization signal. Then, when the controller 52 outputs the vertical synchronization signal, the laser light is modulated and emitted based on the image data input to the laser control unit 59. As a result, an electrostatic latent image is formed on the photosensitive drum 30 and the developing device 32Y
(32C, 32M, 32K) to form a toner image. This toner image is transferred to a recording medium, and is
The image is fixed by 0 to form a fixed image. At this time, the temperature sensor 222 detects the surface temperature (fixing temperature) of the heating roller 212 of the fixing device 40 and outputs the detection result to the overall control unit 5.
Send to 4.

Here, the operation of the copying machine 1 for generating the fixing test images TA to TC in order to detect the glossiness of the fixed image will be described with reference to the flowchart shown in FIG. The subroutine shown in this flowchart is
This is executed after a predetermined number of copies have been made, after a predetermined operating time has elapsed, or when the operator has selected a test mode from the operation panel 53. First, test image data stored in advance in the ROM in the overall control unit 54 is input to the laser control unit 59 shown in FIG. 7, and predetermined fixing test images TA to TC are created by the above-described procedure (FIG. 7). S1).

It is preferable that the fixing test image T is a patch other than black (K), and yellow (Y), cyan (C), and magenta (M) using one type of toner.
Or a patch of an arbitrary color using a plurality of toners. When a plurality of toners are used, the melting state of the toner in various images can be detected. Further, since the amount of toner adhered to the fixing test image T can be increased, the result can be used to widen the amount of toner adhered and other correction ranges. Further, a plurality (three or more) of fixing test images having different image densities by a predetermined value may be created in the recording medium transport direction. In this way, the reflected light intensity (reflectance) of each fixing test image is detected, and a straight line representing the relationship between the image density and the reflected light intensity (reflectance) is obtained from the result by the least square method. The true value of the reflected light intensity (reflectance) for each fixing test image can be obtained. With this, compared to creating only one fixing test image,
The reflected light intensity (reflectance) of the fixing test image can be detected with higher accuracy. Therefore, the image state of the fixing test image can be grasped more accurately. Alternatively, a plurality of (three or more) fixing test images having the same image density may be created in the recording medium transport direction, and an average value of the reflected light intensity (reflectance) for each fixing test image may be obtained.

The surface temperature of the heating roller 212, ie, the fixing temperature when the recording medium S passes through the fixing device 40, is detected by the temperature sensor 222 (S2). Subsequently, the overall control unit 54 calls the test image data stored in the ROM and reads it (S3). Based on the read test image data, each fixing test image TA on the recording medium S is read. To TC (hereinafter, also referred to as “toner required adhesion amount”) (S)
4). Specifically, the required toner adhesion amount is calculated from the relationship between the image density information and the required toner adhesion amount shown in FIG. 9 (actually, the relationship of this graph is stored in the ROM as table data). Next, the image information detecting unit 43
Are the intensity IbA, IbB, IbC of the specular reflection light of the fixing test images TA, TB, TC, and the halogen lamp 41
A, 41B, 41C Emission Intensities IaA, IaB, IaC
Is detected, the general control unit 54 calculates the glossiness of each of the fixing test images TA to TC using these (S5).

Subsequently, the general control section 54 actually adheres to each of the fixing test images TA to TC based on the glossiness of each of the fixing test images TA to TC and the fixing temperature detected in S2. The toner amount (hereinafter, also referred to as "the actual toner adhesion amount") is estimated (S6). Specifically, the overall control unit 54 estimates the actual toner adhesion amount using the graph shown in FIG. 10 or 11 (actually, the relationship of this graph is stored in the ROM as table data).

Next, the rank of the toner adhesion amount difference (difference between the actual adhesion amount and the required adhesion amount) is calculated for the fixing test image TA (S7). The rank of the difference in toner adhesion amount is divided into seven stages (A to G ranks) as shown in Table 1. The case where there is no difference between the actual toner adhesion amount and the required toner adhesion amount is defined as a standard (D rank). The cases where the actual adhesion amount is larger than the required adhesion amount and the case where the actual adhesion amount is smaller are classified into three levels.

[0056]

[Table 1]

Then, the charge voltage value in the first charger is corrected in accordance with the rank of the difference in toner adhesion amount (S8). Thereby, the first charging charger 31A
Since the amount of toner adhering to the area where electric charge is applied to the photosensitive drum 30 approaches the required amount, the fixing test image TA
Is also substantially equal to the required toner adhesion amount.

The overall control unit 54 also calculates the rank of the toner adhesion amount difference for the fixing test image TB (S
9) Second charging charger 3 according to the calculated rank
The charge voltage value in 1B is corrected (S10). As a result, the second charging charger 31B moves the photosensitive drum 3
Since the amount of toner adhering to the region where the electric charge is applied to 0 approaches the required amount of adhesion, the actual amount of adhesion of the toner of the fixing test image TB is also substantially equal to the required amount of toner.

Further, the overall control unit 54 calculates the rank of the toner adhesion amount difference also for the fixing test image TC (S
11) The charge voltage value of the third charging charger 31C is corrected according to the calculated rank (S12).
As a result, the amount of toner adhering to the region where the third charging charger 31C applies electric charge to the photosensitive drum 30 approaches the required amount of adhesion, so that the actual amount of toner adhesion of the fixing test image TC also becomes substantially equal to the required amount of toner adhesion. .

As described above, the actual toner adhesion amount of each of the fixing test images TA to TC approaches the required toner adhesion amount, so that if each of the fixing test images TA to TC is created based on the same test image data, each of the fixing test images TA to TC To TC, the actual toner adhesion amounts become substantially equal. Therefore, when an image is formed in such a state, a fixed image in a good image state with less variation is created.

Here, the correction control of the charge voltage value of the charging charger 31 shown in the subroutine of FIG. 8 will be described with specific numerical values. The fixing test image TA
To TC are 22 in the maximum of 256 levels of image density information.
It is assumed that a third tone is created. Also, the first
Since the same control is performed for the charging charger 31A, the second charging charger 31B, and the third charging charger 31C, the first charging charger 31A will be described as a representative example in the following description.

First, in S1, a fixing test image TA is created. At this time, it is assumed that the temperature sensor 222 detects that the fixing temperature is, for example, 170 ° C. in S2. From the test image data (density data whose image density information is the 223th gradation out of a maximum of 256 gradations) obtained in S3, the overall control unit 54 uses the graph of FIG. It is calculated to be 9 mg / cm ² . On the other hand, it is assumed that the glossiness of the fixing test image TA is calculated to be 66 in S5. Then, in S6, the overall control unit 54 sets the actual toner adhesion amount of the fixing test image TA to 1. based on the table data created from the graph of FIG. 10 (or FIG. 11).
Estimated to be 1 mg / cm ² .

The overall control unit 54 determines the difference between the actual toner adhesion amount and the required toner adhesion amount by 0.2 mg / cm ² (= 1.
1−0.9), and based on Table 1, if the rank of the difference in toner adhesion amount is calculated to be the C rank, a correction is made in S8 to increase the charge voltage value of the first charging charger 31A by + 40V. As a result, the amount of toner adhering to the area where the first charging charger 31A applies electric charge to the photosensitive drum 30 approaches the required amount of adhesion, so that the actual amount of toner adhering to the fixed image is substantially equal to the required amount of toner adhesion. Become.

As described above in detail, according to the copying machine 1 of the first embodiment, predetermined fixing test images TA to TC are created on the recording medium S periodically or by an operator's selection. Is done. Then, the overall control unit 54
The required toner adhesion amount is calculated based on the test image data. Further, the glossiness of each of the fixing test images TA to TC is calculated based on the reflected light intensity and the like obtained by the image information detection unit 43. Further, based on the calculated glossiness and the surface temperature (fixing temperature) of the heating roller 212 detected by the temperature sensor 222, the actual toner adhesion amount of each of the fixing test images TA to TC is estimated. After that, the overall control unit 54
The actual toner adhesion amount and the required toner adhesion amount are compared to calculate the rank of the toner adhesion amount difference, and the charge voltage values in the first to third charging chargers 31A to 31C are corrected according to the rank.

That is, since the charge voltage values in the first to third chargers 31A to 31C are respectively corrected so as to be substantially equal to the required toner adhesion amount, an appropriate amount of toner adheres to each of the fixing test images TA to TC. Therefore, the fixing is performed in a state where there is no variation in the direction orthogonal to the recording medium conveyance direction and a proper amount of toner is attached. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and the need to use OHP sheets having poor appearance.

(Second Embodiment) Next, a second embodiment will be described. The copying machine according to the second embodiment has substantially the same basic configuration as that of the copying machine 1 according to the first embodiment. The difference is that the developing bias voltage value applied to the provided developing roller is corrected. That is, the overall control unit 54 issues an instruction to the high voltage control unit 58 to correct the developing bias voltage values in the developing units 320Y to 320K. Along with this, the configuration of the developing device is also the first
This is different from the embodiment. Therefore, the configuration of the developing device will be described with reference to FIGS. 12 and 13, and then control for correcting the developing bias voltage value will be described with reference to the flowchart shown in FIG. The description of the same components as those in the first embodiment, the copy operation, and the like is omitted, and the same components are denoted by the same reference numerals. Further, the developing devices 320Y, 320M, 32
Since the configurations of 0C and 320K are all the same, the color codes Y, M, C and K are omitted as appropriate in the following description.

As shown in FIG. 12, the developing device 320 of this embodiment has three developing devices, that is, a first developing device 323A,
The image forming apparatus includes a second developing device 323B and a third developing device 323C. As shown in FIG. 13, the first developing device 323A and the third developing device 323C are
Is provided at the same angular position in the circumferential direction of the second developing device 3.
23B is a first developing device 323A and a third developing device 323C.
(An angle position slightly advanced in the rotation direction of the photosensitive drum 30). These developing devices 3
23A to 323C are developing rollers 322A to 322C, respectively.
322C, and these developing rollers 322A to 322C are provided.
Power supplies 321A to 321 for applying a developing bias voltage to C
C. These power supplies 321A to 321C are
Each is connected to the high-voltage control unit 58 (see FIG. 7). Then, the first developing device 323 is controlled by the high-pressure controller 58.
A, second developing device 323B, and third developing device 323C
Can supply toner to the photosensitive drum 30 under different developing conditions. The first developing device 3
A fixing test image TA is created in an area where 23A supplies toner to the photosensitive drum 30. In a similar relationship, the second developing device 323B is connected to the photosensitive drum 30.
A fixing test image TB is created in a region where the toner is supplied to the photoconductor drum 30 in a region where the toner is supplied to the photosensitive drum 30 by the third developing device 323C.

Next, control for correcting the developing bias voltage value will be described with reference to the flowchart shown in FIG. The subroutine shown in this flowchart is
This is executed after a predetermined number of copies have been made, after a predetermined operating time has elapsed, or when the operator has selected a test mode from the operation panel 53. First, test image data stored in advance in the ROM in the integrated control unit 54 is input to the laser control unit 59 shown in FIG. S21). Further, the surface temperature of the heating roller 212 when the recording medium S passes through the fixing device 40, that is, the fixing temperature is detected by the temperature sensor 222 (S22).

Subsequently, the general control unit 54 calls and reads the test image data stored in the ROM (S23), and calculates the required toner adhesion amount based on the read test image data. (S24). Specifically, the required toner adhesion amount is calculated from the relationship between the image density information and the required toner adhesion amount shown in FIG. 9 (actually, the relationship of this graph is stored in the ROM as table data). Next, the image information detecting unit 43 detects the regular reflection light intensities IbA and Ib of the fixing test images TA, TB and TC.
B, IbC, and halogen lamps 41A, 41B, 4
When the emission intensities IaA, IaB and IaC of 1C are detected,
The overall control unit 54 uses these to determine each fixing test image TA.
The glossiness of TC is calculated (S25).

The fixing test images TA to TC
And the fixing temperature detected in S22,
The actual toner adhesion amount of each of the fixing test images TA to TC is estimated (S26). Specifically, the actual toner adhesion amount is estimated using a graph shown in FIG. 10 or 11 (actually, the relationship of this graph is stored in the ROM as table data).

Next, the overall control unit 54 calculates the rank of the toner adhesion amount difference (the difference between the actual adhesion amount and the required adhesion amount) for the fixing test image TA (S27). The rank of the difference in toner adhesion amount is classified into seven stages (A to G ranks) as shown in Table 2, and the case where there is no difference between the actual toner adhesion amount and the required toner adhesion amount is defined as a standard (D rank). The cases where the actual adhesion amount is larger than the required adhesion amount and the case where the actual adhesion amount is smaller are classified into three levels.

[0072]

[Table 2]

Then, the developing bias voltage value in the first developing device is corrected according to the rank of the difference in the amount of toner adhesion (S28). As a result, the amount of toner adhering to the area where the first developing device 323A applies toner to the photosensitive drum 30 approaches the required amount of adhesion, so that the actual amount of toner adhesion of the fixing test image TA also becomes substantially equal to the required amount of toner adhesion. .

The overall control unit 54 also calculates the rank of the toner adhesion amount difference for the fixing test image TB (S2).
9) The developing bias voltage value in the second developing device 323B is corrected according to the calculated rank (S30). As a result, the amount of toner adhering to the area where the second developing device 323B applies toner to the photosensitive drum 30 approaches the required amount of adhesion, so that the actual amount of toner adhesion of the fixing test image TB also becomes substantially equal to the required amount of toner adhesion. .

Further, the overall control unit 54 calculates the rank of the toner adhesion amount difference also for the fixing test image TC (S
31), the third developing device 323C according to the calculated rank.
Is corrected (S32). As a result, the amount of toner adhering to the area where the third developing device 323C applies toner to the photosensitive drum 30 approaches the required amount of adhesion, so that the actual amount of toner adhesion of the fixing test image TC also becomes substantially equal to the required amount of toner adhesion. .

As described above, since the actual toner adhesion amount of each of the fixing test images TA to TC approaches the required toner adhesion amount, if each of the fixing test images TA to TC is created based on the same test image data, each of the fixing test images TA to TC To TC, the actual toner adhesion amounts become substantially equal. Therefore, when an image is formed in such a state, a fixed image in a good image state with less variation is created.

As described above in detail, according to the copying machine according to the second embodiment, the predetermined fixing test image T on the recording medium S is periodically or selected by the operator.
A to TC are created. Then, the overall control unit 54 calculates the required toner adhesion amount based on the test image data.
Further, the glossiness of each of the fixing test images TA to TC is calculated based on the reflected light intensity and the like obtained by the image information detection unit 43. Further, based on the calculated glossiness and the surface temperature (fixing temperature) of the heating roller 212 detected by the temperature sensor 222, the actual toner adhesion amount of each of the fixing test images TA to TC is estimated. Thereafter, the overall control unit 54 compares the actual toner adhesion amount with the required toner adhesion amount to calculate the rank of the toner adhesion amount difference, and sends the first to third developing devices 323A to 323C according to the rank. The developing bias voltage values applied to the provided developing rollers 322A, 322B, 322C are respectively corrected.

That is, since the developing bias voltage values in the first to third developing units 323A to 323C are respectively corrected so as to be substantially equal to the required toner adhesion amount, an appropriate amount of toner is contained in each of the fixing test images TA to TC. As a result, the toner is adhered, and there is no variation in the direction perpendicular to the recording medium conveyance direction, and fixing is performed with an appropriate amount of toner attached. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and the need to use OHP sheets having poor appearance.

(Third Embodiment) Next, a third embodiment will be described. The copying machine according to the third embodiment has substantially the same basic configuration as that of the copying machine 1 according to the first embodiment. The difference is that the transfer voltage value is corrected. That is, the overall control unit 54
Issues an instruction to the high voltage control unit 58 to
The transfer voltage value at 0 is corrected. Accordingly, the configuration of the transfer charger is also different from that of the first embodiment. Therefore, the configuration of the transfer charger will be described with reference to FIGS. 15 and 16, and then control for correcting the transfer voltage value will be described with reference to the flowchart shown in FIG. The description of the same components as those in the first embodiment, the copy operation, and the like is omitted, and the same components are denoted by the same reference numerals.

The transfer charger 330 of the present embodiment
As shown in FIG. 15, three transfer chargers, ie, the first
It includes a transfer charger 33A, a second transfer charger 33B, and a third transfer charger 33C. Then, as shown in FIG. 16, the first transfer charger 33A
And the third transfer charger 33C are provided at the same angular position in the circumferential direction of the photosensitive drum 30, and the second transfer charger 33B is provided at an angular position (slightly different from the photosensitive drum 3
0 (an angular position advanced in the direction opposite to the rotation direction). These transfer chargers 33A to 33C are respectively connected to power supplies 331A to 331C and charge wires 33A.
2A to 332C, and power supplies 331A to 331
C are connected to the high-voltage control unit 58 (see FIG. 7). Then, the first transfer charger 33A, the second transfer charger 33B, and the third transfer charger 33C are controlled by the high-voltage controller 58 under different transfer conditions.
The toner image formed on the recording medium can be transferred onto a recording medium. The fixing test image TA is created in an area where the first transfer charger 33A can transfer the toner image on the photosensitive drum 30. In a similar relationship, the second transfer charger 33B is connected to the photosensitive drum 30.
A fixing test image TB is created in the area where the upper toner image can be transferred, and the third transfer charger 33 </ b> C is
Fixing test image TC in the area where toner image on
Is created.

Next, control for correcting the transfer voltage value in the transfer charger 330 will be described with reference to the flowchart shown in FIG. The subroutine shown in this flowchart is executed after a predetermined number of copies have been made, after a predetermined operating time has elapsed, or when the operator has selected a test mode from the operation panel 53. First, test image data stored in advance in the ROM in the overall control unit 54 is input to the laser control unit 59 shown in FIG. 7, and predetermined fixing test images TA to TC are created by the above-described procedure (FIG. 7). S41). The surface temperature of the heating roller 212 when the recording medium S passes through the fixing device 40, that is, the fixing temperature is detected by the temperature sensor 222 (S42).

Subsequently, the overall control unit 54 calls and reads the test image data stored in the ROM (S43), and calculates the required toner adhesion amount based on the read test image data. (S44). Specifically, the required toner adhesion amount is calculated from the relationship between the image density information and the required toner adhesion amount shown in FIG. 9 (actually, the relationship of this graph is stored in the ROM as table data). Next, the image information detecting unit 43 detects the regular reflection light intensities IbA and Ib of the fixing test images TA, TB and TC.
B, IbC, and halogen lamps 41A, 41B, 4
When the emission intensities IaA, IaB and IaC of 1C are detected,
The overall control unit 54 uses these to determine each fixing test image TA.
The glossiness of TC is calculated (S45).

The fixing test images TA to TC
And the fixing temperature detected in S42,
The actual toner adhesion amount of each of the fixing test images TA to TC is estimated (S46). Specifically, the actual toner adhesion amount is estimated using a graph shown in FIG. 10 or 11 (actually, the relationship of this graph is stored in the ROM as table data).

Next, the overall control unit 54 calculates the rank of the toner adhesion amount difference (the difference between the actual adhesion amount and the required adhesion amount) for the fixing test image TA (S47). The rank of the difference in toner adhesion amount is divided into seven stages (A to G ranks) as shown in Table 3, and the case where there is no difference between the actual toner adhesion amount and the required toner adhesion amount is defined as a standard (D rank). The cases where the actual adhesion amount is larger than the required adhesion amount and the case where the actual adhesion amount is smaller are classified into three levels.

[0085]

[Table 3]

Then, the transfer voltage value in the first transfer charger is corrected according to the rank of the difference in toner adhesion amount (S48). As a result, the toner amount that the first transfer charger 33A moves from the photosensitive drum 30 onto the recording medium S approaches the required amount, so that the actual toner adhesion amount of the fixing test image TA also becomes substantially equal to the toner required adhesion amount.

The overall control unit 54 also calculates the rank of the toner adhesion amount difference for the fixing test image TB (S4).
9) The second transfer charger 3 according to the calculated rank
The transfer voltage value in 3B is corrected (S50). As a result, the toner amount that the second transfer charger 33B moves from the photosensitive drum 30 onto the recording medium S approaches the required amount, so that the actual toner adhesion amount of the fixing test image TB becomes substantially equal to the toner required adhesion amount.

Further, the overall control unit 54 calculates the rank of the toner adhesion amount difference also for the fixing test image TC (S
51) The transfer voltage value in the third transfer charger 33C is corrected according to the calculated rank (S52). As a result, the third transfer charger 33C moves the photosensitive drum 30
Since the amount of toner to be moved onto the recording medium S from above approaches the required amount, the actual toner adhesion amount of the fixing test image TC also becomes substantially equal to the required toner amount.

As described above, since the actual toner adhesion amount of each of the fixing test images TA to TC approaches the required toner adhesion amount, if each of the fixing test images TA to TC is created based on the same test image data, each of the fixing test images TA to TC To TC, the actual toner adhesion amounts become substantially equal. Therefore, when an image is formed in such a state, a fixed image in a good image state with less variation is created.

As described above in detail, according to the copying machine according to the third embodiment, the predetermined fixing test image T on the recording medium S is periodically or selected by the operator.
A to TC are created. Then, the overall control unit 54 calculates the required toner adhesion amount based on the test image data.
Further, the glossiness of each of the fixing test images TA to TC is calculated based on the reflected light intensity and the like obtained by the image information detection unit 43. Further, based on the calculated glossiness and the surface temperature (fixing temperature) of the heating roller 212 detected by the temperature sensor 222, the actual toner adhesion amount of each of the fixing test images TA to TC is estimated. Thereafter, the overall control unit 54 calculates the rank of the difference in toner adhesion amount by comparing the actual toner adhesion amount and the toner required adhesion amount, and according to the rank, the first to third transfer chargers 33A to 33C. The transfer voltage values are respectively corrected.

That is, the transfer voltage values in the first to third transfer chargers 33A to 33C are respectively corrected so as to become substantially equal to the required toner adhesion amount, so that an appropriate amount of toner adheres to each of the fixing test images TA to TC. As a result, fixing is performed in a state where there is no variation in the direction orthogonal to the recording medium conveyance direction and an appropriate amount of toner is attached. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and the need to use OHP sheets having poor appearance.

(Fourth Embodiment) Next, a fourth embodiment will be described. The copying machine according to the fourth embodiment has substantially the same basic configuration as the copying machine 1 according to the first embodiment, but instead of correcting the charge voltage value of the charging charger, the copying machine in the fixing device is used. The difference is that the fixing temperature is corrected. That is, the overall control unit 54 corrects the control temperature of the heater lamp in the fixing device.
Accordingly, the configuration of the fixing device is also different from that of the first embodiment. Further, the toner adhesion amount is not compared, and the actually measured glossiness (hereinafter, also referred to as “measured glossiness”) is compared with the glossiness to be originally obtained (hereinafter, also referred to as “required glossiness”). The second embodiment is also different in that the process conditions (fixing temperature in this embodiment) are corrected. Therefore, the configuration of the fixing device will be described with reference to FIG. 18, and then control for correcting the control temperature value will be described with reference to the flowchart shown in FIG. The description of the same components as those in the first embodiment, the copy operation, and the like is omitted, and the same components are denoted by the same reference numerals.

As shown in FIG. 18, the fixing device 400 of this embodiment includes a heating roller 412 and a pressure roller 413.
Is provided with three heater lamps, that is, a first heater lamp 421A, a second heater lamp 421B, and a third heater lamp 421C. These heater lamps 421A to 421C are connected to the overall control unit 54, and the first heater lamp 421A and the second heater lamp 42
1B and the third heater lamp 421C can be set at different temperatures. Thus, when the toner image transferred onto the recording medium S is fixed on the recording medium S, the control temperatures (i.e., fixing temperatures) of the respective heater lamps 421A to 421C can be set separately.

Next, control for correcting the fixing temperature in the fixing device 400 will be described with reference to the flowchart shown in FIG. The subroutine shown in this flowchart is performed after a predetermined number of copies have been made, after a predetermined operation time has elapsed, or when the operator
3 is executed when the test mode is selected. First, test image data stored in advance in the ROM in the overall control unit 54 is input to the laser control unit 59 shown in FIG. 7, and predetermined fixing test images TA to TC are created by the above-described procedure (FIG. 7). S61).
Further, the surface temperature of the heating roller 412 when the recording material S passes through the fixing device 400, that is, the fixing temperature is
Detection is performed at 2A, 422B, and 422C (S62).

Subsequently, the general control unit 54 calls the test image data stored in the ROM and reads it (S63), and based on the read test image data and the fixing temperature, the required glossiness is determined. Is calculated (S6
4). Next, the image information detecting unit 43 detects the regular reflection light intensities IbA, IbB, I of the fixing test images TA, TB, TC.
When detecting the bC and the light emission intensities IaA, IaB, IaC of the halogen lamps 41A, 41B, 41C, the overall control unit 54 uses these to determine each of the fixing test images TA to TC.
Is calculated (S65).

Next, the overall control unit 54 calculates the rank of the gloss difference (the difference between the measured gloss and the required gloss) for the fixing test image TA (S66). The rank of the gloss difference is divided into seven stages (A to G ranks) as shown in Table 4 and the measured gloss is defined as a standard (D rank) when there is no difference between the measured gloss and the required gloss. The cases where the glossiness is higher than the required glossiness and the case where the glossiness is lower than the required glossiness are classified into three levels.

[0097]

[Table 4]

Then, depending on the rank of the gloss difference, the first
The control temperature value of the heater lamp 421A is corrected (S67). As a result, the toner is appropriately melted in the fixing area covered by the first heater lamp 421A, so that the measured glossiness of the fixing test image TA becomes close to the required glossiness.

The overall control unit 54 calculates the rank of the gloss difference for the fixing test image TB (S68),
The control temperature value of the second heater lamp 421B is corrected according to the rank (S69). As a result, the toner is appropriately melted in the fixing area covered by the second heater lamp 421B, so that the measured glossiness of the fixing test image TB becomes close to the required glossiness.

Further, the overall control unit 54 calculates the rank of the gloss difference for the fixing test image TC (S7).
0), the control temperature value of the third heater lamp 421C is corrected according to the rank (S71). This allows
Since the toner is appropriately melted in the fixing area covered by the third heater lamp 421C, the measured glossiness of the fixing test image TC is close to the required glossiness.

As described above, since the actually measured glossiness of each of the fixing test images TA to TC approaches the required glossiness, if each of the fixing test images TA to TC is created based on the same test image data, each of the fixing test images TA to TC , The measured gloss levels are almost equal. Therefore, when an image is formed in such a state, a fixed image in a good image state with less variation is created.

As described above in detail, according to the copying machine of the fourth embodiment, a predetermined fixing test image T
A to TC are created. Then, the overall control unit 54 generates the test image data and the temperature sensors 422A, 422B, 42.
The required glossiness is calculated based on 2C. Further, based on the reflected light intensity and the like obtained by the image information detection unit 43, the measured glossiness of each of the fixing test images TA to TC is calculated. Then, the overall control unit 54 compares the measured glossiness with the required glossiness to calculate the rank of the glossiness difference, and according to the rank, controls the control temperature values of the first to third heater lamps 421A to 421C. Are respectively corrected.

That is, since the control temperature values of the first to third heater lamps 421A to 421C are respectively corrected so as to be substantially equal to the required glossiness, the toner adhering to each of the fixing test images TA to TC is appropriately melted. As a result, there is no variation in the direction perpendicular to the recording medium conveyance direction, and the toner is melted and fixed. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and the need to use OHP sheets having poor appearance.

In the above-described fourth embodiment, the control temperatures of the heater lamps 421A, 421B, 421C are corrected based on the difference between the required glossiness and the measured glossiness. As illustrated in the third embodiment, the required toner adhesion amount and the actual toner adhesion amount are calculated, and each heater lamp 421A, 421B, 421C is calculated based on the difference between the calculated required toner adhesion amount and the actual toner adhesion amount.
The same effect can be obtained even if the control temperature is corrected.

(Fifth Embodiment) Next, a fifth embodiment will be described. The configuration of the copying machine according to the fifth embodiment is substantially the same as that of the copying machine 1 according to the first embodiment, but the fixing test image creation position is different. Specifically, as shown in FIG. 20, the fixing test images T1 and T2 are created in the transport direction of the recording medium. Another difference is that the image information detecting unit 53 for detecting the reflected light intensity information of the fixing test image includes only one set of the halogen lamp 41 and the CCD sensor 42. This makes it possible to grasp the variation in the recording medium transport direction within one recording medium. Thus, for example, when using a thick paper or an OHP sheet that takes a large amount of heat from the fixing device 40 due to a large heat capacity, even if the image state is good near the leading end of the recording medium S, the supply of the heat amount to the fixing device 40 is possible. In some cases, the fixing temperature gradually decreases and the image state deteriorates near the rear end. However, such a situation can be prevented from occurring.

When the fixing test images T1 and T2 are created, the image information detecting section 53 sequentially detects the regular reflection intensities Ib1 and Ib2 of the fixing test images T1 and T2. Then, from the detection result, the integrated control unit 54 calculates the measured glossiness in each of the fixing test images T1 and T2, and further calculates the difference in the glossiness. The fixing test images T1 and T2 are created after a predetermined number of copies have been made, after a predetermined operating time has elapsed, or when an operator selects a test mode from the operation panel 53. In the present embodiment, the measured glossiness is calculated assuming that the emission intensity Ia of the halogen lamp 41 is always constant.

Then, the overall control unit 54 changes the interval at which recording materials are loaded into the fixing device 40 based on the difference in glossiness.
Specifically, the graph shown in FIG. 21 is stored in the ROM as table data in advance, and the table data is used to correct the input time interval (in the present embodiment, the number of sheets of recording material held on the transfer drum 34). ) Is calculated. For example, assuming that the difference between the measured gloss levels of the fixing test images T1 and T2 is 12%, the transfer drum 34
Is reduced by two from the reference number (three) to one. That is, in the present embodiment, the overall control unit 54 and the transfer drum 34 correspond to a charging time interval correcting unit.

Thus, for example, when a recording medium requiring a large amount of heat for fixing such as an OHP sheet is used, the time interval for feeding the recording medium into the fixing device 40 is widened, and thus the time required for the next fixing operation is increased. Is performed in a state where appropriate fixing conditions are set. Therefore, the toner image can be fixed to the recording medium as quickly as possible while maintaining a good image state of a certain level or more under the current control conditions of the fixing device 40.

As described above in detail, according to the copying machine of the fifth embodiment, the predetermined fixing test image T on the recording medium S is periodically or selected by the operator.
1, T2 are created. Then, based on the reflected light intensity and the like obtained by the image information detection unit 43, the general control unit 54 calculates the gloss difference after calculating the measured gloss levels in the fixing test images T1 and T2, respectively. Next, the number of recording media held on the transfer drum 34 is changed based on the difference in glossiness.

That is, the number of recording mediums held on the transfer drum 34 is changed so that appropriate fixing conditions are established before the next fixing operation is performed. The toner image can be fixed on the recording medium as quickly as possible while maintaining a good image state. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and the need to use OHP sheets having poor appearance.

In the fifth embodiment described above, the number of recording mediums held on the transfer drum 34 is corrected based on the gloss difference between the fixing test images T1 and T2. As exemplified in the embodiment, the same effect can be obtained by estimating the actual toner adhesion amount in the fixing test images T1 and T2 and correcting the number of recording mediums held on the transfer drum 34 based on the difference between the actual toner adhesion amounts. Obtainable.

(Sixth Embodiment) Finally, a sixth embodiment will be described. The copying machine according to the sixth embodiment has substantially the same configuration as the copying machine 1 according to the first embodiment, but does not create a test image but reflects a fixed image obtained by copying a normal original. The difference is that the light intensity information is detected and the process conditions in the image forming process condition changing means are corrected. The process condition correction program is executed after a predetermined number of copies have been made, after a predetermined operating time has elapsed, or when the operator has selected. In the first embodiment, three sets of the halogen lamp 41A and the like and the CCD sensor 42A and the like are used.
In the present embodiment, two sets of halogen lamps 91A and 91B
And a pair of CCD sensors 92A and 92B. Hereinafter, regarding the processing of the intensity information including the variation,
This will be described with reference to FIG. Note that the copy operation and the test image creation operation are the same as those in the first embodiment, and therefore description thereof is omitted, and the same components are denoted by the same reference numerals. Also, halogen lamps 91A and 91B
It is assumed that the light emission intensity is constant.

When the process condition correction program is executed, first, the image reading section 2 (see FIG. 1) obtains image data corresponding to the image of the document. Next, the area RA in which the image information detection unit 93 can detect the intensity information of the reflected light of the fixed image G
1, RA2, RA3, ... and RB1, RB2, RB3, ...
In this case, it is checked in which area the fixed image G (image data) exists. For example, in the case shown in FIG. 22, it is found that a fixed image exists in the areas RA2 and RB2. Then, an instruction to detect the intensity information of the reflected light in the areas RA2 and RB2 is issued from the IR control unit 51 (see FIG. 7) to the image information detection unit 93 via the overall control unit 54. Next, a copy image (fixed image) of the document is formed on the recording medium S based on the read image data by the above-described electrophotographic process.

Then, the overall control unit 54 controls the temperature sensor 2
The surface temperature (fixing temperature) of the heating roller 212 detected at 22 and the image data of the areas RA2 and RB2 stored in the data memory unit 9 provided in the image reading unit 2 are read. Next, the respective required toner adhesion amounts are calculated from the image data in the areas RA2 and RB2. Next, the image information detecting section 93 sends the recording medium S from the fixing device 40.
Is discharged, and at the timing when the areas RA2 and RB2 reach the detection area of the image information detection section 93, the image information detection section 93 reflects the intensity IgA of the reflected light of the fixed image G by the CCD sensor 92A by the CCD sensor 92B. The light intensity IgB is measured.

Then, the overall control unit 54 calculates the measured gloss level in the areas RA2 and RB2 of the fixed image G. Further, based on the measured glossiness in the areas RA2 and RB2 of the fixed image G and the fixing temperature detected by the temperature sensor 222, the amount of toner adhering to the areas RA2 and RB2, that is, the actual amount of toner adhering is estimated. Then, the actual amount of toner adhering to the areas RA2 and RB2 of the fixed image G is compared with the required amount of adhering toner to estimate the rank (see Table 2) of the difference in the amount of adhering toner. The process conditions in the forming process condition changing means are corrected. Specifically, the developing bias voltage value of the developing device 32Y and the like is corrected as shown in Table 2.

By such correction, fixing is performed in a state where an appropriate amount of toner has adhered to the recording medium S. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and the need to use OHP sheets having poor appearance.

Instead of correcting the developing bias voltage value of the developing device 32Y or the like, as described in the above embodiment, the condition for applying the charge to the photosensitive drum 30 (charging condition), the transfer condition, or the charging condition. The time interval may be corrected. Further, as exemplified in the fourth and fifth embodiments, it is also possible to calculate the required gloss level and compare the calculated gloss level with the measured gloss level, thereby correcting the process conditions in the image forming process condition changing means. it can.

As described above, according to the copying machine of the sixth embodiment, when the process condition correction program is executed, the image information detecting section 93 can measure the image data of the original to be copied. The image information detecting unit 93 checks whether or not there is image data in the area, and if there is image data, its position (for example, the areas RA2 and RB2).
However, when detecting the intensities IgA and IgB of the reflected light in the areas RA2 and RB2 of the fixed image G, the general control unit 54 calculates the measured glossiness using these. Further, the heating roller 2 detected by the actually measured gloss and the temperature sensor 222 is used.
12, the toner actual adhesion amounts in the areas RA2 and RB2 estimated based on the surface temperature (fixing temperature) of the image forming apparatus 12 and the toner required adhesion calculated from the image data corresponding to the areas RA2 and RB2 stored in the data memory unit 9. The rank of the difference in toner adhesion amount is calculated by comparing the amount with the amount. Thereafter, the overall control unit 54 corrects process conditions including development conditions, transfer conditions, and the like according to each rank.

By such correction, fixing is performed in a state where an appropriate amount of toner has adhered to the recording medium S. Therefore, it is possible to obtain a fixed image in which a favorable image state is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and the need to use OHP sheets having poor appearance.

The above-described embodiment is merely an example, and does not limit the present invention in any way. Needless to say, various improvements and modifications can be made without departing from the gist of the present invention. For example, in each of the above-described embodiments, the image information detecting unit 43 detects the specularly reflected light of the fixed image, but as shown in FIG.
The CCD sensors 62A to 62C in FIG.
And more specifically, at a position off the optical axis of the specularly reflected light,
The recording medium S passing through C is arranged on the normal line of the paper surface. That is, the normal line and the optical axis 62AL of the CCD sensors 62A to 62C.
62CL, and the image information detector 63 detects the intensity I of the diffuse reflection light of the fixing test images TA to TC.
It is also possible to detect cA to IcC and detect the reflectance of diffuse reflection light. The diffusely reflected light refers to reflected light that is incident on the fixed image and is scattered by irregularities of the fixed image and travels in a direction other than the direction of regular reflection. And "diffuse reflected light" in the same sense).

As described above, in the image information detecting section 63,
The reason why the reflectance of the diffuse reflection light of the fixing test image T is detected is that it is possible to accurately estimate the amount of adhered toner. In other words, the reflectance of diffuse reflected light has a narrower detection range compared to the reflectance and glossiness of specular reflected light, but has a negative correlation with the amount of adhered toner, and its value increases greatly with a change in the amount of adhered toner. This is because, because of the change, it is possible to accurately estimate the amount of toner adhesion.

As shown in FIG. 24, the CCD sensors 42A to 42C in the image information detecting section 73 are so set as to receive specularly reflected light of the incident light from the halogen lamps 41A to 41C, respectively. Is the optical axis 41A of each of the halogen lamps 41A to 41C.
By fixing the fixing test images TA to TC in the image information detecting unit 73 by arranging the intersections PA to PC between the L to 41CL and the recording medium S on the normal to the paper surface of the recording medium S passing through the intersections PA to PC. The intensities IbA to IbC of the specular reflection light and the intensities IcA to IcC of the diffuse reflection light may be detected.

As described above, in the image information detecting section 73,
By detecting the regular reflection lights IbA to IbC and the diffuse reflection light intensities IcA to IcC of the fixing test images TA to TC, an intensity ratio between the regular reflection light and the diffuse reflection light is obtained. The reason for this is that, when used for estimation or the like, it becomes stronger against disturbances such as fluctuations in the luminous intensities IaA to IaC of the halogen lamps 41A to 41C, and the estimation of the amount of adhered toner can be performed more accurately.

Further, if the light emission intensities IaA to IaC of the halogen lamps 41A to 41C are always kept constant, the image forming process condition changing means can be performed based on the intensity information of the reflected light without obtaining the reflectance and glossiness of the fixed image. Can be corrected. In addition, by detecting not only the intensity information of the reflected light of the fixed image but also the intensity information of the transmitted light and the color shift (shift of brightness, hue, and saturation), the process in the image forming process condition changing means can be similarly performed. The condition can be corrected.

That is, when correcting the process conditions in the image forming process condition changing means based on the intensity information of the transmitted light of the fixed image, the transmitted light intensity of the fixed image may be detected as described below. . That is, for example, as shown in FIG. 25, the halogen lamps 141A to 141C provided on the lower side in the figure are located at the following positions.
What is necessary is just to provide a CD sensor.

(1) Halogen lamps 141A to 141C
The CCD sensor 142 is located on the upper side in the figure so as to sandwich the conveyance path of the recording medium S coaxially with the optical axes 141AL to 141CL.
A to 142C are provided. Thereby, the fixing test image T
The intensity IdA to IdC of transmitted light (hereinafter also referred to as “straight transmitted light”) in which incident light incident on A to TC travels straight without being bent by refraction or the like can be detected. (2) Optical axis 1
The CCD sensors 162A to 162 are located at positions deviated from the optical axes 141AL to 141CL, while allowing the intersections PA to PC of the recording medium S to be seen.
C is provided. Thereby, the intensity IeA to Ie of the transmitted light (hereinafter, also referred to as “refracted transmitted light”) in which the incident light that has entered the fixing test images TA to TC has its path bent by refraction or the like.
C can be detected. (3) CCD sensors 142A to 142
C and CCD sensors 162A to 162C. Thereby, both the intensities IdA to IdC of the straight transmitted light and the intensities IeA to IeC of the refracted transmitted light can be detected.

Also, based on the information on the color shift of the fixed image,
When correcting the process conditions in the image forming process condition changing means, for example, as described below,
What is necessary is just to detect the transmitted light intensity after the color separation of the fixed image. That is, for example, as shown in FIG. 26, the optical axes 141AL to 141C of the halogen lamps 141A to 141C are compared with the halogen lamps 141A to 141C provided on the lower side in the figure.
RGB filters 139A to 139C including a red (R) filter, a green (G) filter, and a blue (B) filter are provided on the L and between the halogen lamps 141A to 141C and the recording medium S, as follows. CCD in position
A sensor may be provided.

(1) Halogen lamps 141A to 141C
The CCD sensor 142 is located on the upper side in the figure so as to sandwich the conveyance path of the recording medium S coaxially with the optical axes 141AL to 141CL.
A to 142C are provided. Thereby, the fixing test image T
Intensities IdRA of straight transmitted light after color separation in A to TC
To IdRC, IdGA to IdGC, IdBA to IdBC
Can be detected. (2) While allowing the intersections PA to PC between the optical axes 141AL to 141CL and the recording medium S to be seen, C is located at a position deviated from each of the optical axes 141AL to 141CL.
CD sensors 162A to 162C are provided. This allows
Intensity of refracted transmitted light after color separation in fixing test images TA to TC IeRA to IeRC, IeGA to IeGC, I
eBA to IeBC can be detected. When correcting the process conditions in the image forming process condition changing means based on the information on the color shift of the fixed image, the intensity of the reflected light after color separation may be detected.

Further, in the above-described first to sixth embodiments, only one of the charging condition, the developing condition, the transfer condition, and the fixing condition among the process conditions in the image forming process condition varying means is corrected. Although the case is illustrated, two or more process conditions may be corrected at the same time, for example, the charging condition and the developing condition are corrected at the same time. By simultaneously correcting a plurality of conditions as described above, it is possible to increase the correction range of the amount of adhered toner or to finely correct the amount of adhered toner to appropriately melt the toner.

Further, in the above-described embodiment, a roller fixing type is exemplified as the contact heating fixing means, but the present invention is not limited to this, and a belt fixing type may be used.
Further, in the above-described embodiment, an example in which the present invention is applied to a copying machine has been described. However, the present invention can be applied to any apparatus having an image forming apparatus such as a printer such as a page printer or a facsimile.

[0131]

As described above, according to the image forming apparatus of the present invention, the image information detecting means is fixed to at least two or more positions of the recording medium which are different in the direction perpendicular to the recording medium conveyance direction. The image information of the fixed image is detected. Then, the image forming process condition correcting unit calculates a change in the image information of the fixed image from the detection result of the image information detecting unit, and corrects the process condition in the image forming process condition changing unit so as to suppress the change. As a result, fixing is performed in a state where an appropriate amount of the developer is adhered to the recording medium without variation. For this reason, it is possible to obtain a fixed image in which a good image state without variation is stably secured. Therefore, it is possible to avoid re-use of unnecessary copies and use of an OHP sheet having a poor appearance.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a copying machine according to a first embodiment.

FIG. 2 is a perspective view showing a configuration of a transfer charger in the copying machine of FIG.

FIG. 3 is a side view of the transfer charger of FIG. 2;

FIG. 4 is a sectional view showing a configuration of a fixing device in the copying machine of FIG.

FIG. 5 is a perspective view illustrating a configuration of an image information detection unit in the copying machine of FIG. 1;

FIG. 6 is a perspective view illustrating another configuration of the image information detection unit.

FIG. 7 is a block diagram showing a part of a control circuit of the copying machine shown in FIG. 1;

FIG. 8 is a flowchart illustrating control for correcting a charging condition.

FIG. 9 is a diagram illustrating a relationship between image density information and a required toner adhesion amount.

FIG. 10 is a diagram illustrating a relationship between glossiness and toner adhesion amount when a fixing temperature is constant.

FIG. 11 is a diagram illustrating a relationship between a fixing temperature and a gloss level when a toner adhesion amount is constant.

FIG. 12 is a perspective view illustrating a configuration of a developing device according to a second embodiment.

FIG. 13 is a side view of the developing device of FIG.

FIG. 14 is a flowchart illustrating control for correcting a process condition (development condition) according to the second embodiment.

FIG. 15 is a perspective view illustrating a configuration of a transfer charger according to a third embodiment.

FIG. 16 is a side view of the developing device of FIG.

FIG. 17 is a flowchart illustrating control for correcting a process condition (transfer condition) according to the third embodiment.

FIG. 18 is a cross-sectional view illustrating a configuration of a fixing device according to a fourth embodiment.

FIG. 19 is a flowchart illustrating control for correcting a process condition (fixing condition) according to the fourth embodiment.

FIG. 20 is an explanatory diagram for describing a method of detecting image information in an image information detection unit in a copying machine according to a fifth embodiment.

FIG. 21 is a diagram illustrating a relationship between a difference in gloss and a correction amount of the number of recording mediums held on a transfer drum.

FIG. 22 is an explanatory diagram for describing a method of detecting image information in an image information detection unit in a copying machine according to a sixth embodiment.

FIG. 23 is a perspective view showing another configuration of the image information detection unit.

FIG. 24 is a perspective view showing another configuration of the image information detecting unit.

FIG. 25 is a perspective view showing another configuration of the image information detection unit (in the case where the transmitted light intensity of a fixed image is detected).

FIG. 26 is a side view showing another configuration of the image information detection unit (in the case where the transmitted light intensity of the fixed image after color separation is detected).

[Explanation of symbols]

 5 Image Processing Unit 30 Photoconductor Drum 31 Charger 31A to 31C First to Third Charger 312A to 312C Charge Wire 32Y, 32C, 32M, 32K Developing Device 33 Transfer Charger 34 Transfer Drum 40 Fixing Device 41A to 41C Halogen Lamp 42A To 42B CCD sensor 43 Image information detection unit 54 Overall control unit 212 Heating roller 213 Pressing roller 221 Heater lamp 222 Temperature sensor S Recording medium TA to TC Fixing test image

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H027 DA09 DA12 DE02 DE07 DE10 EA01 EA03 EA05 EA12 EC06 EC07 ED16 EE02 EE08 2H033 AA03 BB00 BB18 CA07 CA18 CA30 CA37 2H073 AA02 BA02 BA13 BA28 CA22 9A001 HH23 KKH

Claims (9)

[Claims] An image forming means for forming an unfixed image on a recording medium based on image data, and a contact heat fixing for fixing the unfixed image generated by the image forming means on the recording body by contact heating. Any one of the image forming means and the contact heating and fixing means, wherein at least one or more of the process conditions of the image forming process are set in a direction perpendicular to the recording medium conveying direction. A light-emitting element for irradiating light to a fixed image fixed on the recording medium by the contact heating and fixing means, and a light-emitting element irradiated from the light-emitting element to reflect or transmit the fixed image; A light receiving element for detecting the intensity information of the recorded light, wherein the position of the recording Image information detecting means for detecting the image information of the fixed image at two or more locations; calculating a change in the image information of each fixed image from the detection result of the image information detecting means; An image forming apparatus comprising: an image forming process condition correcting unit that corrects a process condition in a forming process condition changing unit. 2. The image forming apparatus according to claim 1, further comprising: a fixing temperature detecting unit configured to detect a fixing temperature of the contact heating fixing unit, wherein the image forming process condition correcting unit includes the image information and the fixing unit. An actualized image agent amount estimating unit for estimating an actual image agent amount actually used to create the fixed image based on the temperature, and a detection corresponding to a detection area of the image information detecting unit in the image data Having a required developer amount calculating means for calculating a required developer amount originally required to create the fixed image based on the area image data, and from the realized image agent amount and the required developer amount An image forming apparatus comprising: calculating a change in a developer amount of the fixed image; and correcting a process condition in the image forming process condition changing unit based on the change. 3. The image forming apparatus according to claim 1, further comprising: a fixing temperature detecting unit configured to detect a fixing temperature of the contact heating fixing unit; Request image information calculation means for calculating required image information to be originally obtained based on the fixing temperature; calculating a change in the image information of the fixed image from the image information and the requested image information; An image forming apparatus that corrects a process condition in the image forming process condition changing unit based on the image processing process. 4. The image forming apparatus according to claim 1, wherein the image forming process condition changing unit is configured to move a charging unit that applies a charge to the photoconductor to a direction perpendicular to a recording medium conveyance direction. A plurality of charging units, each of which is capable of changing the charging conditions of the plurality of chargers, and the image forming process condition correcting unit is a charging condition correcting unit that corrects the charging conditions of the chargers. An image forming apparatus comprising: 5. The image forming apparatus according to claim 1, wherein the image forming process condition changing unit supplies a developer to an electrostatic latent image on a photoconductor. The developing device includes a plurality of carriers in a direction perpendicular to the recording medium conveyance direction, and is a divided developing unit that can change a developing bias voltage value applied to the plurality of developer carriers, respectively. An image forming apparatus comprising: a developing condition correcting unit configured to correct a developing bias voltage value applied to each developer carrier. 6. The image forming apparatus according to claim 1, wherein the image forming process condition changing unit transfers a visible image on a photoconductor onto the recording medium. Are provided in a direction orthogonal to the recording medium transport direction, and each of the transfer currents and the transfer voltages in the plurality of transfer units can be changed. An image forming apparatus comprising: a transfer condition correcting unit for correcting any one of a transfer current and a transfer voltage in a device. 7. The image forming apparatus according to claim 1, wherein the image forming process condition changing unit includes a plurality of the heaters in a direction orthogonal to a recording material conveying direction. An image forming process condition correcting unit configured to change a control temperature of each of the plurality of heaters; and an image forming process condition correcting unit configured to correct a control temperature of each of the heaters. Forming equipment. 8. An image forming apparatus comprising: an image forming unit that forms an unfixed image on a recording body; and a fixing unit that fixes the unfixed image created by the image forming unit on the recording body. A light-emitting element that irradiates light to a fixed image fixed on the recording medium by a fixing unit; and a light-receiving element that detects intensity information of light that is emitted from the light-emitting element and reflects or transmits the fixed image. Image information detecting means for detecting image information of at least two or more fixed images at different positions in the recording medium transport direction in the recording medium; and image information of each of the fixed images based on a detection result by the image information detecting means. Calculating a variation with respect to, the input time interval correction means for correcting the input time interval of feeding the recording medium from the image creating means to the fixing means based on the change,
An image forming apparatus comprising: 9. The image forming apparatus according to claim 1, wherein the image forming unit stores test image data for forming a predetermined test image on the recording medium. An image forming apparatus, comprising: a test image data memory for detecting the intensity of light transmitted or reflected by a fixed test image fixed on the recording medium.