JPH10239978A - Developer residual amount detecting method, image forming apparatus and process cartridge - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a toner remaining amount detection method capable of accurately detecting toner consumption regardless of the type of image data. SOLUTION: Data defining the number of continuous pixel signal dots according to the total number of pixel signal dots based on image information for one page and a correction coefficient relating to the toner consumption of the number of continuous pixel signal dots are stored in advance in the total pixel signal. A plurality of dots are prepared for each number of dots, and the number of continuous pixel signal dots according to the data selected according to the total number of pixel signal dots is multiplied by the correction coefficient and the amount of toner consumption per dot. The toner consumption for one page is obtained by successively adding the toner consumption for each page, and the toner consumption is subtracted from the initial toner amount to obtain the toner remaining amount. Ask.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus using a laser beam modulated by print data, for example, a laser beam printer or a copying machine, and a detachable image forming apparatus. The present invention relates to a process cartridge to be mounted, and a method for detecting a remaining amount of a developer in the image forming apparatus or the process cartridge.

[0002]

2. Description of the Related Art An electrophotographic image forming apparatus such as a laser beam printer is a page printer that forms an image at a time when all data of one page are prepared. Such an image forming apparatus forms a latent image by irradiating an electrophotographic photosensitive member with light corresponding to image information sent from an external computer or the like, and the latent image is a recording material by a developing unit. An image is formed on the recording paper by supplying a developer (toner) to visualize the image, and further transferring the image from the photoconductor to the recording paper.

[0003] A toner storage portion for storing toner is connected to a developing roller as a developing means, and the toner is consumed by forming an image. Therefore, in order to prevent the toner in the toner storage unit from being depleted and sudden image defects to occur, the presence or absence of toner near the developing unit is detected, and a signal indicating that the toner is going to run out is connected to the printer itself or the printer. The information is sent to a display means such as a host computer to notify the user.

There are various detection methods for detecting the presence / absence of toner. For example, a piezoelectric sensor for detecting the presence / absence of toner based on whether or not toner is in contact with the toner, a magnetic sensor in the case of magnetic toner, and supplying toner to a photosensitive member When an AC bias is applied to the developing roll, there is an antenna sensing type or the like. In any case, it is a so-called toner near-end detection that detects that the toner is almost exhausted.

As a method for detecting the presence or absence of toner without providing the above-described sensor for detecting the presence or absence of toner in the developing means, an individual pixel signal for forming a dot is counted, and the counted number is used as the toner consumption. For example, Japanese Patent Application Laid-Open No. Sho 58-224363 proposes a toner remaining amount detecting method for calculating the amount of consumed toner on the assumption that the amount of consumed toner is proportional to the toner amount.

[0006]

In the above-mentioned conventional method for counting individual pixel signals forming dots, the following method is used.
There is no problem if the number of dots is proportional to the amount of toner consumption, but there is a drawback that an error occurs if the number of dots is not proportional to the amount of toner consumption depending on the type of image. In particular, when the developing unit develops using a potential difference from an electrostatic latent image, the amount of toner consumed per dot differs between an image having a large area and an image composed of lines. Since the lines of electric force between the latent image and the developing portion are dense at the boundary of the latent image, that is, where the surface potential changes abruptly, toner tends to collect at the boundary (edge) of the image during development. Further, since the toner is developed along the lines of electric force, the amount of toner consumption differs between an image formed from fine lines such as characters and a large area (solid) image when converted into the same number of pixel dots.

Accordingly, it is a main object of the present invention to provide a method for detecting a remaining amount of a developer which can accurately detect a consumption amount of a developer regardless of the type of image data, and an image forming apparatus using the method for detecting a remaining amount of a developer. And a process cartridge using the developer remaining amount detection method detachably mounted on an image forming apparatus.

Another object of the present invention is to provide an image forming apparatus having an accessible storage means for storing the remaining amount of the developer so as to know the remaining amount of the developer obtained by the method for detecting the remaining amount of the developer. It is to be.

Another object of the present invention is to provide a process cartridge having an accessible storage means for storing the remaining amount of developer in order to know the remaining amount of developer obtained by the method for detecting the remaining amount of developer. To provide.

[0010]

The above object is achieved by a method for detecting a remaining amount of a developer, an image forming apparatus and a process cartridge according to the present invention. In summary, the present invention provides a method for detecting the remaining amount of developer used in an electrophotographic image forming apparatus, wherein the number of continuous pixel signal dots corresponding to the total number of pixel signal dots based on image information for one page is determined. A plurality of data defining a correction coefficient for the developer consumption of the number of pixel signal dots is prepared in advance for each of the total number of pixel signal dots,
The number of continuous pixel signal dots according to the data selected according to the total number of pixel signal dots, the correction coefficient, and 1
The amount of developer consumed per dot is multiplied to obtain the amount of developer consumed, and this is repeated for one page, and the amount of developer consumed for one page is obtained by sequentially adding each amount of developer. In addition, a developer remaining amount detecting method is characterized in that a developer remaining amount is obtained by subtracting the developer consumption amount from the initial developer amount.

According to another aspect of the present invention, there are provided means for converting input image information into a light emission control signal, and means for irradiating light on a photosensitive member based on the light emission control signal,
An image forming apparatus that forms an electrostatic latent image on a photoreceptor with the irradiated light, visualizes the electrostatic latent image with a developer of a developing unit, and then transfers and fixes the recording material on a recording material. A plurality of data defining the number of continuous pixel signal dots according to the total number of pixel signal dots according to image information and the correction coefficient relating to the developer consumption of the number of continuous pixel signal dots is prepared in advance for each total pixel signal dot number, The number of continuous pixel signal dots according to the data selected according to the total number of pixel signal dots is multiplied by the correction coefficient and the amount of toner consumption per dot to obtain a developer consumption amount. Means for calculating the amount of developer consumed for one page by repeatedly adding the amount of developer consumed for each page and sequentially obtaining the remaining amount of developer by subtracting the amount of developer consumed from the amount of initial developer. When Image forming apparatus is provided which is characterized in that a means for storing the remaining developer amount.

According to another aspect of the present invention, there are provided means for converting input image information into a light emission control signal, and means for irradiating light on a photosensitive member based on the light emission control signal, A process cartridge detachably mountable to an image forming apparatus for forming an electrostatic latent image on the photoreceptor with the irradiated light, visualizing the electrostatic latent image with a developer of a developing unit, and then transferring and fixing the recording material. In the image forming apparatus, the number of continuous pixel signal dots according to the total number of pixel signal dots based on image information for one page and data defining a correction coefficient for the amount of developer consumption of the number of continuous pixel signal dots are previously determined. A plurality is prepared for each total pixel signal dot number, the continuous pixel signal dot number, the correction coefficient, and the developer consumption per dot according to the data selected according to the total pixel signal dot number. Multiplied by seeking developer consumption,
This is repeated for one page, and the amount of developer consumed for one page is obtained by sequentially adding the amount of developer consumed, and the amount of developer consumed is subtracted from the amount of initial developer to obtain the remaining amount of developer. There is provided a process cartridge having means for calculating the amount, and wherein the process cartridge includes means for storing the remaining amount of the developer determined by the means.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus, a process cartridge and a method for detecting a remaining amount of a developer according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 Embodiment 1 according to the present invention will be described with reference to FIGS.

Data to be printed out from the host computer 4 is sent to the image signal processing section 5 in the image forming circuit 3 as an electric signal. The image signal processing unit 5 generates a laser drive signal based on the data in accordance with a video signal for each scanning line, and controls the laser emission control means 17 to turn off and on the laser emission means 18 to thereby control the photosensitive member 19 serving as an image carrier. Is irradiated.

The laser beam usually has a wavelength of about 780 nm, and a semiconductor laser is used for light emission. The emitted laser light passes through a collimator lens, scanning mirror, f-θ lens, etc., not shown,
9. Irradiate on top.

The photosensitive member 19 is uniformly charged to about -700 V by the charging means 20 before being irradiated with the laser light, and the surface potential of only the portion irradiated with the laser light is lowered to about -150 V to cover the latent image. An image is formed. Outer diameter 30
Since the photosensitive member 19 of mm is rotating in the direction of the arrow in the drawing at a surface speed of 94 mm / sec, latent images are formed one after another, and the latent image portion is in contact with the developing means (developing roller) 24 of the developing device 22. Come to the opposite part.

The developing roller 24 is opposed to the photosensitive member 19, and the toner on the surface of the developing roller 24 is supplied to the latent image portion of the photosensitive member 19 to form a visible image on the photosensitive member 19. At this time, the insulative toner is negatively charged, and when -400 V is applied to the developing roller 24, the toner is attracted to the latent image portion irradiated with the laser light having the reduced potential to form a visible image. Is done.

The visible image on the photoreceptor 19 is transferred to a recording paper conveyed in synchronization by a transfer means 25 which is a transfer roller, and an image is formed on the recording paper. After the recording paper is conveyed to the fixing unit 27 to fix the image on the recording paper,
Output to the outside.

As described above, the latent image on the photosensitive member 19 is developed using the potential difference between the latent image and the developing section. Lines of electric force between the latent image and the developing unit tend to gather at the boundary (edge) of the latent image. This means that the amount of consumption differs between an image formed from fine lines such as characters and a large area (solid) image when converted to the same number of pixel dots.

Actually, a one-component magnetic negative toner having an average particle diameter of about 6.5 μm was used, and a laser beam printer of 600 dpi was used.
The consumption was compared between a 4-dot line (line image) and a 94-dot line (solid image). As a result, the toner consumption per dot was 44 × 10 ^-9 g for the line image and 27 × 10 ^-9 g for the solid image.

As described above, since the amount of toner consumption varies depending on the image, even if the number of image dots is simply counted, it is not possible to determine whether the image is composed of a line or a solid image. Cannot be calculated.

Therefore, in the present invention, the line image (total pixel signal dot number of 1,566,000 or less: Table 1) or the solid image is detected by the total pixel signal dot number detecting means 6 for one page in the consumption calculation circuit 2. (Total pixel signal dot number 6, 26
4,000 or more: Table 3) or the middle thereof (total number of pixel signal dots: 1,566,000 to 6,264,000)
Within: Table 2), and any one of the following Tables 1 to 3 showing the number of continuous pixel dots prepared in advance according to the total pixel signal dot number and the consumption correction coefficient. Select a table (table selection 7).

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

Then, the toner consumption is calculated based on the selected table. That is, the number of continuous dots is detected by the continuous dot number detection means 8, and the correction coefficient corresponding to the number of continuous dots is multiplied by the multiplication means 9;
The multiplied value is stored in the continuous dot consumption storage means 10, the toner consumption calculation is performed in the same manner for one page, and the toner consumption is sequentially added by one page by the addition means 11 to obtain the integrated consumption storage means. 12, the amount of toner consumption for one page can be calculated.

Next, the remaining toner calculating means 13 calculates the remaining amount of toner by subtracting the calculated value of the accumulated consumption amount storing means 12 from the value of the initial toner amount storing means 14 stored in advance. To the remaining toner storage means 15
To memorize. The remaining toner storage means 15 is always accessible, and by transmitting the stored contents to the display means 16 of the printer main body and the host computer 4, the user can know the remaining toner amount of the image forming apparatus 1 at any time. It is.

Here, the calculation process of the toner consumption will be described below with reference to an actual example.

The apparatus of this embodiment is 600 dpi (dot)
per inch) laser beam printer,
Letter size paper (216 mm x 279 m
m) is an image formable area of 204 mm × 269 mm,
When converted to dots, 4,878 dots × 6,420 dots = 31,316,760 dots (total number of dots).
In other words, the approximate image type can be predicted by specifying the printing rate (the ratio of the area of the image formable area to the total area of the printed image), and by taking that into account, a more accurate toner can be obtained. The consumption can be counted.

For example, in the case of this embodiment, the total pixel dot number for one page is set to 1,
Since the printing rate is 1,000,000 dots, the printing rate is determined to be a line image having a printing rate of 5% or less (total pixel signal number: 1,566,000 dots or less), and Table 1 is used for toner consumption calculation (Table selection 7). ).

Next, the number of continuous pixel dots is detected by the continuous pixel dot number detecting means 8, and if the number of continuous dots is 3, for example, the correction count 1 corresponding to the range of 1 to 4 is selected. The multiplying means 9 multiplies the number of continuous dots by 3 and the correction count of 1, and then multiplies by 44 × 10 ^-9 grams of toner consumption per dot to obtain the toner consumption. This is stored in the dot consumption storage unit 10.

Then, the next continuous pixel signal dot number is detected by the continuous pixel dot number detecting means 8. If the continuous dot number is 18, the multiplying means 9 follows the above by the multiplying means 9. ) × 0.9 (correction coefficient) × 4
Multiplication of 4 × 10 ⁻⁹ grams (toner consumption per dot) is performed, and the result is stored in the continuous dot consumption storage unit 10.

Next, the value stored in the continuous dot consumption storage means 10 and the present value are added by the adding means 11.
If the next number of continuous dots is 50 (the correction coefficient is the same for 20 or more), 50 (number of continuous dots) × 0.85 (correction coefficient) × 44 × 10 ^-9 grams (toner consumption per dot) And the toner consumption is stored in the integrated consumption storage unit 12 as described above.

By repeating this operation for one page, the toner consumption for one page can be accurately obtained. Then, the remaining toner amount can be calculated by subtracting the integrated consumption amount from the initial toner amount 14 by the remaining toner calculating means 13 as described above.

In the above description, the toner consumption is calculated by multiplying the number of continuous dots by one dot by the number of continuous dots and the correction coefficient each time, and the toner consumption is calculated. The toner consumption for one page can be calculated by multiplying the sum of each page by the toner consumption per dot at the end.

The total number of pixel signal dots is 6,264.
If it is 000 or more (printing ratio is 20% or more), it is determined that the image is a solid image, the toner consumption is calculated using the number of continuous pixel signal dots and the correction coefficient shown in Table 3, and the number of continuous pixel signal dots is the intermediate (The printing rate is within 5 to 20%), the toner consumption is similarly calculated based on Table 2.

As described above, the table showing the relationship between the number of continuous pixel signal dots and the correction coefficient based on the total number of pixel signal dots is divided into three. The calculation can be performed more accurately than the method of calculating the consumption, and the load on the storage unit can be reduced.

On the other hand, if the relation table according to the total pixel signal dot number is further divided into four or more tables, more accurate toner consumption can be calculated.

Also, in this embodiment, the number of continuous pixel signal dots in Tables 1 to 3 is divided at approximately 5 dot intervals. However, when the number of continuous pixel signal dots is 20 or less, the number decreases substantially linearly. By further dividing the interval of the number of dots, a more accurate toner consumption can be calculated.

Second Embodiment Next, a second embodiment according to the present invention will be described with reference to FIGS.

In this embodiment, an image forming apparatus 1 having substantially the same configuration as that of the first embodiment is provided with a developing unit 22 containing toner 23, a photosensitive member 19 serving as an image carrier, a charging unit 20, and a cleaning unit 26. Is made detachable, and the process cartridge 2
8 is provided with the remaining toner amount storage means 15 in the consumption calculation circuit 2 described in the first embodiment.

The consumption amount calculation circuit 2 provided in the image forming apparatus 1 calculates the toner consumption amount and the remaining toner amount in the same manner as described in the first embodiment, and stores the results in the remaining toner amount storage means 15 of the process cartridge 28. Let it. This storage means 15 is writable, and its contents can be read at any time and can be known by the display means 16 of the image forming apparatus 1 or the host computer 4.

The conversion of the toner consumption calculated by the consumption calculation circuit 2 into the remaining toner amount may be performed by the consumption calculation circuit 2 and the value of the remaining toner amount may be sent to the storage means 15.
The value of the toner consumption is sent to the storage unit 15 and
It is better to subtract from the initial toner amount stored in the memory and store the result.

As described above, the toner remaining amount storage means 15 is provided in the process cartridge 28 which is detachably attached to the image forming apparatus main body 1.
Is advantageous in that, for example, when the process cartridge 28 is replaced, the value of the initial toner amount in the memory of the main body side storage means does not have to be rewritten.

The process cartridge is not limited to the above-described structure, as long as it has a structure including at least the photosensitive member and the developing means.

[0047]

As is apparent from the above description, according to the present invention, the number of continuous pixel signal dots corresponding to the total number of pixel signal dots based on image information for one page, and the development of the number of continuous pixel signal dots Preliminarily prepare a plurality of data for each of the total pixel signal dot number and data defining a correction coefficient for the agent consumption,
The number of continuous pixel signal dots according to the data selected according to the total number of pixel signal dots, the correction coefficient, and 1
The amount of developer consumed per dot is multiplied to obtain the amount of developer consumed, and this is repeated for one page, and the amount of developer consumed for one page is obtained by sequentially adding each amount of developer. At the same time, by subtracting the amount of developer consumed from the initial amount of developer to determine the remaining amount of developer, without requiring a sensor for detecting the remaining amount of developer,
Further, the developer consumption and the remaining amount of the developer can be accurately grasped without depending on the image. Therefore, the remaining amount of the developer can be grasped at any time at low cost.

Further, by providing the image forming apparatus with a means for storing the remaining amount of the developer, it is possible to provide an image forming apparatus capable of ascertaining the remaining amount of the developer at any time at low cost.

Further, by providing the process cartridge with a means for storing the remaining amount of the developer, the remaining amount of the developer is automatically updated when the process cartridge is replaced. The notification can be made accurately, and the circuit of the image forming apparatus main body can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a toner remaining amount detecting method for describing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of the image forming apparatus according to the first exemplary embodiment.

FIG. 3 is a block diagram illustrating a toner remaining amount detection method for explaining a second embodiment;

FIG. 4 is a configuration diagram illustrating an image forming apparatus including a process cartridge according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Consumption calculation circuit 3 Image forming circuit 4 Host computer 15 Remaining toner amount storage means 18 Laser emission means 19 Photoconductor 20 Charging means 22 Developing device 24 Developing roller (developing means) 26 Cleaning means 28 Process cartridge

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Norio Takami 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (5)

[Claims] 1. A method for detecting a remaining amount of a developer used in an electrophotographic image forming apparatus, comprising: the number of continuous pixel signal dots corresponding to the total number of pixel signal dots based on image information of one page; A plurality of data defining a correction coefficient relating to the number of developer consumption is prepared in advance for each total pixel signal dot number, and the continuous pixel signal dots according to the data selected according to the total pixel signal dot number are prepared. The developer consumption is obtained by multiplying the number by the correction coefficient and the developer consumption per dot, and this is repeated for one page, and each developer consumption is sequentially added to obtain one page. A developer remaining amount is obtained by subtracting the developer consumption amount from the initial developer amount and obtaining the remaining developer amount. 2. The apparatus according to claim 1, further comprising: means for converting the input image information into a light emission control signal; and means for irradiating light on the photosensitive member based on the light emission control signal. An image forming apparatus that forms an electrostatic latent image, visualizes the electrostatic latent image with a developer of a developing unit, and then transfers and fixes the electrostatic latent image on a recording material, according to the total number of pixel signal dots based on image information for one page. A plurality of data defining the number of continuous pixel signal dots and the correction coefficient relating to the developer consumption of the number of continuous pixel signal dots are prepared in advance for each total pixel signal dot number, and selected in accordance with the total pixel signal dot number. Multiplying the number of continuous pixel signal dots according to the obtained data by the correction coefficient and the toner consumption per dot to obtain a developer consumption, and repeating this for one page, Are sequentially added Means for calculating the amount of developer consumed for one page, subtracting the amount of developer consumed from the amount of initial developer to obtain the remaining amount of developer, and storing the amount of developer remaining. An image forming apparatus comprising: 3. The means for determining the remaining amount of the developer includes a total dot number detecting means, a continuous image dot number detecting means, a multiplying means, a continuous dot consumption amount storage means, an addition means, and an integrated consumption amount storage. 3. The image forming apparatus according to claim 2, further comprising: a unit; and an initial toner amount storage unit. 4. A device for converting input image information into a light emission control signal, and a device for irradiating light onto a photosensitive member based on the light emission control signal, wherein the irradiated light is applied onto the photosensitive member. A process cartridge detachable from an image forming apparatus for forming an electrostatic latent image, visualizing the electrostatic latent image with a developer of a developing unit, and then transferring and fixing the recording material on a recording material, the image forming apparatus comprising: A plurality of sets of data defining the number of continuous pixel signal dots corresponding to the total number of pixel signal dots based on image information for each minute and a correction coefficient relating to the developer consumption of the number of continuous pixel signal dots are prepared in advance for each of the total pixel signal dot numbers. Multiplying the number of continuous pixel signal dots by the correction coefficient and the amount of developer consumption per dot in accordance with the data selected according to the total number of pixel signal dots to obtain a developer consumption amount; Is repeated for one page, and the amount of developer consumed for one page is obtained by sequentially adding the amount of developer consumed, and the amount of developer consumed is subtracted from the initial amount of developer to obtain the remaining amount of developer. Wherein the process cartridge comprises means for storing the remaining amount of the developer obtained by the means. 5. The process cartridge according to claim 4, further comprising at least a photoconductor and a developing unit.