JP2003262995A - Image forming device - Google Patents

Abstract

(57) Abstract: An image forming apparatus capable of preventing a recording sheet from winding around a fixing device and forming an image on a recording sheet having heat resistance to the fixing device. An image forming apparatus transfers a toner image formed on a photoconductor to a recording sheet and thermally fixes the toner image carried on the recording sheet by a fixing device having a fixing roller. A recording sheet discriminating unit 4 for discriminating whether or not the recording sheet is wound around the fixing roller due to the thermal fixing of the roller, and a conveyance control device for controlling conveyance of the recording sheet are provided. If it is determined that the recording sheet is stuck, the conveyance control device controls so that the recording sheet is not conveyed to the fixing device in a heated state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile and a printer.

[0002]

2. Description of the Related Art Conventionally, the type of recording sheet, for example,
There is known an image forming apparatus that discriminates between plain paper and OHP sheet, between plain paper and coated paper, and performs various controls based on the discrimination result. As a method of discriminating between plain paper and OHP sheet, a method of discriminating using a transmissive sensor is known. In addition, as a method of distinguishing plain paper from coated paper, a method of detecting regular reflection light and diffuse reflection light to determine the presence or absence of surface gloss of the recording sheet, and irradiating light from multiple directions to reflect the surface of the recording sheet A method of making a distinction by utilizing characteristics
No. 11230), a method of scanning the surface of a recording sheet with a stylus to convert changes in unevenness into an electrical signal for determination, and a method of contacting a heating element on the surface of the recording sheet for determination based on temperature change (special feature (Open 2001-201473 gazette)
Is proposed. Further, based on the determination result of the recording sheet, a method of controlling the fixing temperature of the image for each type of the recording sheet (see Japanese Patent Laid-Open No. 8-146815) and a method of controlling the recording condition of the image (Japanese Patent Laid-Open No. 2001-215103). (See gazette) and the like have been proposed.

[0003]

In recent years, ink jet type image forming apparatuses have been rapidly spread, and accordingly, ink jet recording sheets are used. As this ink jet recording sheet, a coated paper having a surface layer coated with a coating material having a softening point lower than the heat fixing temperature of an electrophotographic system is often used. There is a case where the recording sheet is intentionally set in an electrophotographic image forming apparatus to form an image by mistake or with the idea that high image quality may be obtained. The heat of the fixing device of the electrophotographic image forming apparatus softens the coating material on the surface layer of the recording sheet, and the recording sheet is wound around the fixing roller.

In order to solve this problem, it is conceivable to use a conventional method for discriminating between plain paper and coated paper and control the conveyance of the recording sheet based on the discrimination result. In this case, control is performed so as to stop the conveyance to the fixing device which is in a heated state for all the papers that are determined to be coated papers.

On the other hand, in the electrophotographic image forming apparatus,
In some cases, a coated paper having a surface layer coated with a coating material having a softening point higher than the heat fixing temperature of a fixing device is used to achieve high image quality. However, in the image forming apparatus that performs control using the above-described conventional determination method, such electrophotographic coated paper and inkjet coated paper are controlled to stop conveyance to the fixing device without distinction. It Therefore, if it is attempted to prevent the coated paper for inkjet from winding around the fixing roller, it becomes impossible to form an image using the coated paper for electrophotography. Particularly, in the case of using a coated paper having heat resistance to a fixing device as a dedicated paper such as a wet electrophotographic system, control cannot be performed using the above-mentioned conventional determination method.

The present invention has been made in view of the above background, and an object of the present invention is to prevent the recording sheet from being wound around the fixing device and to form an image on the recording sheet having heat resistance to the fixing device. An object of the present invention is to provide an image forming apparatus that can perform formation.

[0007]

In order to achieve the above object, the invention of claim 1 transfers a toner image formed on an image carrier to a recording sheet, and the toner carried on the recording sheet. In an image forming apparatus in which an image is heat-fixed by a fixing device having a fixing roller, a recording sheet determination unit that determines whether or not the recording sheet is wound around the fixing roller by heat fixing of the fixing roller, and a recording sheet determination unit When a conveyance control device for controlling conveyance is provided and it is determined by the recording sheet determination means that the recording sheet is wound around the fixing roller,
The conveyance control device controls the recording sheet not to be conveyed to the heating fixing device. In the image forming apparatus according to the first aspect, it is determined whether or not the recording sheet is wound around the fixing roller by heat fixing of the fixing roller. If it is determined that the recording sheet is wound around the fixing roller, the recording sheet is controlled so as not to be conveyed to the heating fixing device. Therefore, it is possible to prevent the recording sheet from being wrapped around the fixing roller. On the other hand, when it is determined that the recording sheet is not wound around the fixing roller, the recording sheet is conveyed to the heating fixing device and the image forming operation is performed. According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the recording sheet discriminating means softens the heat treatment device for heating a part of the recording sheet and the heating portion heated by the heat treatment device. And a softening determining device for determining whether or not the heating portion of the recording sheet is softened, and determining that the recording sheet is wound around the fixing roller. It is a thing. The invention of claim 3 is the same as claim 2
In the image forming apparatus, the heat treatment device includes a heating unit for heating a part of the recording sheet by bringing a heating element into contact therewith, and the softening determination device detects a surface state detecting device for detecting a surface state of the recording sheet. The heating device heats a part of the recording sheet at a temperature set on the basis of the surface temperature of the fixing roller, and the surface state detection device causes the surface states of the heated portion and the non-heated portion of the recording sheet. Detect
It is characterized by comparing the surface state detection results of the heated portion and the non-heated portion to determine whether or not the heated portion of the recording sheet has softened. According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the coated paper is arranged on the upstream side of the heat treatment device in the recording sheet conveying direction, and the recording sheet has a coating layer on its surface. A coated paper discriminating device for discriminating whether or not the recording sheet is detected by the heat treatment device of the recording sheet discriminating means only when the coated paper discriminating device discriminates that the recording sheet is a coated paper. It is characterized by heating a part. According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, when the recording sheet determination means determines that the recording sheet winds around the fixing roller, the conveyance control device determines that the recording sheet is the recording sheet. The present invention is characterized in that the transportation is stopped or the transportation is stopped after the transportation to a position designated in advance. The invention of claim 6 relates to claims 1 to 5.
In any one of the image forming apparatuses, when the recording sheet determination unit determines that the recording sheet is wound around the fixing roller, the conveyance control unit conveys the recording sheet from the recording sheet determined by the recording sheet determination unit. Control for continuing the image forming operation of the recording sheet on the downstream side in the direction, and stopping the transportation of the recording sheet on the upstream side of the recording sheet in the transport direction of the recording sheet, or for stopping the transportation after transporting to a predetermined position. It is characterized by doing. According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the toner image is transferred to the recording sheet on the downstream side of the recording sheet discriminating unit in the recording sheet conveying direction. When a recording sheet separating / conveying path that separates and conveys the recording sheet is provided on the upstream side of the transfer unit, and the recording control unit determines that the recording sheet is wound around the fixing roller, The recording sheet is conveyed to the recording sheet separation conveyance path, and when it is determined that the recording sheet is not wound around the fixing roller, the recording sheet is controlled to be conveyed to the transfer portion. Is. According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the image forming apparatus further comprises a temporary storage section for temporarily storing the recording sheet conveyed to the recording sheet separating / conveying path, and the conveyance control device is the recording sheet discriminating means. The recording sheet determined to be wound around the fixing roller is conveyed to the recording sheet separating and conveying path and stored in the temporary storing section. According to a ninth aspect of the present invention, in the image forming apparatus according to the seventh aspect, a fixing temperature control device for controlling the temperature of the fixing roller is provided, and when the recording sheet is conveyed to the separation conveyance route by the conveyance control device, After the conveyance of the recording sheet is stopped, the temperature of the fixing roller is lowered by the fixing temperature control device, and the temperature of the fixing roller becomes equal to or lower than a preset temperature. Is controlled to be discharged to the outside of the machine via the fixing device. According to a tenth aspect of the invention, in the image forming apparatus according to any one of the first to tenth aspects, the recording sheet type detection is arranged upstream of the recording sheet discriminating means in the recording sheet conveying direction and discriminates the type of the recording sheet. An apparatus and a storage device that stores the detection result of the recording sheet type determination device and the result of the determination whether the recording sheet is wound around the fixing roller by the recording sheet determination means, and the recording sheet type detection The detection result of detecting the type of the recording sheet by the device and the result of the determination of whether the recording sheet is wound around the fixing roller by the recording sheet determination means are stored in the storage device,
The type of the recording sheet newly conveyed by the recording sheet type detecting device is detected, and when the detection result is compared with the detection result stored in the storage device, the recording sheet discriminating means newly detects The recording sheet newly conveyed by the above-mentioned conveyance control device is regarded as matching the judgment result stored in the storage device without judging whether or not the recording sheet conveyed to the above is wound around the fixing roller. It is characterized in that the conveyance of the sheet is controlled. According to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, the recording sheet type detection device detects a paper thickness of the recording sheet, and a glossy paper that detects whether or not the recording sheet is glossy paper. It is characterized by comprising a detection device and a front / back detection device for determining whether the front and back surfaces are the same. According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the second to eleventh aspects, a size detection device for detecting the size of the recording sheet is provided upstream of the recording sheet determination unit in the recording sheet conveyance direction, The heat treatment device is configured to heat the peripheral portion of the recording sheet based on the size information of the recording sheet detected by the size detection device. The invention of claim 13 is the same as claim 2.
The image forming apparatus according to any one of 1 to 12 includes a fixing temperature detecting unit that detects the surface temperature of the fixing roller,
The heating temperature of the recording sheet by the heat treatment device is set based on the surface temperature of the fixing roller detected by the fixing temperature detecting means. Claim 1
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the second to thirteenth aspects, the heating time for heating the recording sheet by the heat treatment device is set based on the linear velocity of the recording sheet. Is. According to a fifteenth aspect of the invention, in the image forming apparatus according to any one of the first to fourteenth aspects, there is provided display means for displaying the determination result when the recording sheet determination means determines that the recording sheet winds around the fixing roller. It is characterized by having.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to an image forming apparatus such as a copying machine, a facsimile and a printer will be described below. FIG. 1 is a schematic configuration diagram of an image forming apparatus according to this embodiment. In this image forming apparatus, a charging device 11, an exposure device 12, a developing device 13, a transfer device 14, and a cleaning device 15 are sequentially arranged around a photoconductor 7 as an image carrier. Further, a paper feeding device 16 for feeding the recording sheet T on the transfer body from the paper feeding tray 1.
And a conveying device 17 for feeding the recording sheet T toward the facing portion of the photoconductor 7 and the transfer device 14. Also,
After the recording sheet T on which the toner image formed on the photoconductor 7 is transferred is separated from the photoconductor 7, the toner is transferred to the recording sheet T.
A fixing device having a fixing roller 8 for fixing to

In the image forming apparatus constructed as above,
The image forming apparatus rotationally drives the photoconductor 1 in response to an image formation start signal. The surface of the rotating photoconductor 7 is uniformly charged by the charging device 11, and then the exposure device 12 is charged based on the image information.
And a latent image is formed on the photoconductor 7. A toner image is formed by attaching toner charged by the developing device 13 to the electrostatic latent image formed on the photoconductor 7. On the other hand, in response to an image formation start signal, the recording sheet T is fed from the paper feeding tray 1 by the paper feeding device 16, and then is conveyed by the conveying device 17 to the transfer section where the photoconductor 7 and the transfer device face each other. Then, the transfer device 14 transfers the toner image formed on the photoconductor 7 to the recording sheet T by applying an electric charge having a polarity opposite to that of the toner image on the photoconductor 7 to the recording sheet T. Then, the recording sheet T
Is separated from the photoconductor 7 and is sent to a fixing device having a fixing roller 8 in a heated state, and the toner is heat-fixed to the recording sheet T to obtain an image.

Next, the discrimination processing section of the recording sheet T will be described. A coated paper discriminating device 2, a size detecting device 3, and a recording sheet discriminating unit means 4 are sequentially arranged in the conveying path of the conveying device 17 for the recording sheet T. The coated paper discriminating apparatus 2 discriminates whether or not the recording sheet T is a coated paper, and uses a known coated paper discriminating method.
Specifically, it detects specular reflection light, specular reflection light, and diffuse reflection light to determine the presence or absence of surface gloss of the recording sheet, and irradiates light from multiple directions to utilize the reflection characteristics of the recording sheet surface. Use the one that determines. It is also possible to use one that scans the surface of the recording sheet T with a stylus and converts the change in the unevenness into an electrical signal for determination. As the size detecting device 3, a known device is used which is provided with a large number of optical sensors and detects the size based on the presence or absence of the paper at the detection position of each optical sensor. The recording sheet discriminating means 4 includes a heat treatment device 41 for heat-treating a part of the recording sheet T,
The heat treatment device 41 includes a softening determination device 42 that determines whether or not the heating portion is softened. The heat treatment device 41 includes a heating unit that moves so as to come into contact with the surface of the recording sheet T and heat-treats a part of the surface of the recording sheet T. The softening determination device 42 includes a surface state detection device having a reflective optical sensor that detects the surface states of the heated portion and the non-heated portion of the recording sheet T. Further, in the conveyance direction of the recording sheet T, the separation conveyance path 5 is provided on the downstream side of the recording sheet determination means 4 and on the upstream side of the portion facing the transfer device 14. Further, a temporary storage tray 6 that can store a plurality of recording sheets T is provided as a temporary storage unit that temporarily stores the recording sheets conveyed to the separation conveyance path 5.

The recording sheet T is fed from the paper feed tray 1 by the paper feeding device 16 and conveyed to the coated paper discriminating device 2, and the coated paper discriminating device 2 discriminates whether or not it is coated paper. When the coated paper discriminating device 2 discriminates that the coated paper is not the coated paper, it is discriminated that it is not wound around the fixing roller. At this point, it is determined that the fixing roller should not be wound, so the sheet is conveyed to the transfer portion without the size detection by the size detection device 3 and the determination processing by the recording sheet determination means 4. Then, after the toner image is transferred at the transfer portion, the toner image is conveyed to a fixing device and heat fixing is performed.

On the other hand, the recording sheet T discriminated as coated paper by the coated paper discriminating device 2 is conveyed to the size detecting device 3 and its size is detected. Next, the recording sheet T is conveyed by the heat treatment device 41 of the recording sheet discrimination means 4. The heat treatment device 41 moves the heating unit to the right peripheral portion set in advance with respect to the conveyance direction of the recording sheet according to the size detected by the size detection device 3, and abuts against the recording sheet T. The surface is heated. The heating temperature by the heating unit is set to be the same as or slightly higher than the surface setting temperature of the fixing roller 8. Next, the surface state detection device of the softening determination device 42 detects the surface states of the heated portion and the non-heated portion of the recording sheet T. Then, the detection results of both are compared to determine whether the surface state has changed due to heating. When the detection results of both are regarded as the amount of unevenness on the surface, it is considered that if the unevenness of the heated portion is larger than the unevenness of the non-heated portion by a preset threshold value or more, the surface shape is softened or melted by heating and changed. It is determined that the surface layer of the recording sheet, which is considered to have changed in surface state, is softened or melted by the heating of the fixing roller and wound around the fixing roller. Therefore, in order not to convey to the fixing roller 8 in the heated state, the conveyance control device stops the conveying roller on the conveying path or conveys to the separation conveying path 5. The recording sheet T conveyed to the separation conveyance path 5 is stored in the temporary storage tray 6. It should be noted that the heating temperature of the recording sheet T is the same as the fixing temperature or higher than a preset fixing temperature by detecting the fixing roller surface temperature by the surface temperature detecting means 9 in the vicinity of the fixing roller surface and feeding it back. You may control to.

Further, in the recording sheet whose surface state has not been changed from the detection result of the surface state detecting device, the surface layer is not softened or melted by the heating of the fixing roller and is wound around the fixing roller 8. It is determined that there is no. Therefore, it is conveyed to the transfer unit through the normal conveyance path. After the toner image is transferred on the recording sheet T at the transfer portion, the recording sheet T is conveyed to a fixing device and heat-fixed.

Since the recording sheet heat-treated by the heat treatment device 41 is coated paper, its surface is smoother than plain paper. Therefore, when heat treatment is performed by the heat treatment device 41, the surface of the recording sheet is softened into the shape of the heating portion, and the surface becomes uneven. In order to improve the detection accuracy of this change in the surface state, the surface shape of the heating portion is formed into a lattice shape or a halftone dot shape, and when the surface of the recording sheet is softened, the surface shape is likely to be uneven. Further, by disposing rollers that are movable in the recording sheet conveying direction on both sides of the heating unit, the structure is such that the recording sheet can be smoothly conveyed even when the recording sheet is stuck to the heating unit and a conveyance load is generated.

Hereinafter, the present invention will be described in more detail with reference to examples. (Example 1) The first sheet of the sheet feed tray 1 was plain paper, and the second sheet of inkjet paper was set to form an image. The softening temperature of the coating material applied to the surface layer of the inkjet paper is lower than the set temperature of the fixing roller. FIG. 2 shows a flowchart of the first embodiment. When image formation is started, the first sheet of the set recording sheet is picked up and conveyed to the coated paper discriminating apparatus 2. The coated paper discriminating apparatus 2 discriminates that the recording sheet T is not a coated paper. Therefore, the recording sheet T is conveyed to the fixing section via the transfer section in the normal conveyance path. In this way, normal image recording is performed on the first plain paper. For the first recording sheet, the size detection device 3 does not detect the size, and the recording sheet determination unit 4 does not heat or detect the surface state.

Next, as with the first recording sheet, the second recording sheet is picked up and the recording sheet T is conveyed to the coated paper discriminating apparatus 2. The coated paper discriminating apparatus 2 discriminates that the recording sheet T is coated paper and conveys it to the size detecting apparatus 3. Then, the size detection device 3 detects the size of the second recording sheet T. Next, the recording sheet T is conveyed to the heat treatment device 41 of the recording sheet discrimination means 4. The heat treatment device 41, based on the size information detected above,
The heating unit is moved to the right peripheral portion set in advance with respect to the conveyance direction of the recording sheet T. Then, the heating unit heats the right peripheral surface of the recording sheet T. The heating temperature at this time is set by the temperature information detected by the surface temperature detecting means 9 of the fixing roller. Specifically, the heating temperature should be the same as the surface detection temperature of the fixing roller +
The temperature is controlled to be 5 ° C higher. Also, the heating time is
It is set by the linear velocity of the recording sheet. The heat-treated recording sheet T is conveyed to the softening determination device 42. In the softening determination device 42, the surface state detection device detects the surface states of the heated portion and the non-heated portion of the recording sheet T. When the detection results of both are compared and the difference is determined, it is considered that the surface layer of the second recording sheet T is softened or melted by heating. From this, it is determined that when the recording sheet T is conveyed to the heating fixing device, the surface of the recording sheet is softened and is wound around the fixing roller 8. Therefore, the conveyance control device immediately stops the recording sheet T on the conveyance path so as not to convey the recording sheet T to the heating fixing roller 8. Therefore, the recording sheet T stops on the transport path after passing through the recording sheet determination means 4. Then, after the conveyance of the recording sheet is stopped,
The display on the operation unit informs the user and requests that the stopped recording sheet be taken out.

The second recording sheet is the fixing roller 8
When it is determined that the first recording sheet is wrapped around, the image recording of the first recording sheet is still being performed, and the sheet has not been discharged from the apparatus. Therefore, the first recording sheet T, which is a recording sheet in the downstream process from the second recording sheet, continues image recording and is discharged after the recording is completed.

(Embodiment 2) An embodiment will be described in which, when an inkjet paper is mixed and set between plain papers, the conveyance is controlled by using the separation / conveyance path 5. Similar to Example 1, this inkjet paper is a coated paper having a surface layer coated with a coating material having a softening temperature lower than the set temperature of the fixing roller. An image was recorded by setting plain paper as the first sheet of the paper feed tray 1, inkjet paper as the second sheet, plain paper as the third sheet, inkjet paper as the fourth sheet, inkjet paper as the fifth sheet, and inkjet paper as the fifth sheet. Further, in this embodiment, the recording sheets T are stored in the temporary storage tray 6 of the separation / conveyance path 5.
It is possible to store one.

FIG. 3 shows a row chart of the second embodiment. When image formation is started, the first sheet of the set recording sheet is picked up and conveyed to the coated paper discriminating apparatus 2. As in the first embodiment, the coated paper discriminating apparatus 2 discriminates that the first recording sheet T is not a coated paper. Therefore, the recording sheet T
Is conveyed to the fixing unit via the transfer unit in a normal conveyance path, and normal image recording is performed. At this time, the size detection by the size detection device 3 in the transport path, and
The recording sheet discrimination means 4 does not heat or detect the surface condition.

Next, the second recording sheet is picked up and conveyed to the coated paper discriminating apparatus 2. Coated paper discriminating device 2
In the same manner as in Example 1, the recording sheet T is determined to be coated paper and is conveyed to the size detection device 3. Then, the size detection device 3 detects the size of the second recording sheet T. Next, the recording sheet T is conveyed to the recording sheet determination means 4. The recording sheet discriminating unit 4 discriminates that the recording sheet discriminating unit 4 winds around the fixing roller 8 as in the first embodiment. Therefore, the conveyance control device controls the recording sheet T so that the recording sheet T is not conveyed to the heating fixing roller 8.
Are transported to the separation transport path 5 and stored in the temporary storage tray 6.

Similarly, the third recording sheet is conveyed to the coated paper discriminating apparatus 2 and discriminated as plain paper. Therefore,
Similar to the first sheet, a normal image is recorded and then ejected.

Then, the fourth recording sheet is conveyed,
Similar to the second recording sheet, it is determined that the fixing roller 8 is wound around. Therefore, the conveyance control means stores the fourth recording sheet T in the temporary storage tray 6 of the separation conveyance path 5 in the same manner as the second sheet so as not to convey it to the fixing roller 8 in the heated state.

Then, the fifth recording sheet is conveyed,
Similar to the second and fourth sheets, it is determined to be wound around the fixing roller. Here, the temporary storage tray 6 of the separation conveyance path 5
Is full, the conveyance of the fifth recording sheet is immediately stopped.

Here, a fixing temperature control device (not shown) controls to lower the temperature of the fixing roller. Then, when the temperature becomes equal to or lower than the specified temperature, the recording sheet stored in the temporary storage tray 6 of the separation conveyance path 5 is discharged. Then, the stopped recording sheet is discharged onto the separation conveyance path 5. After the three recording sheets have passed the fixing roller, the fixing temperature control device returns the temperature of the fixing roller to the original fixing temperature.

(Embodiment 3) When an inkjet paper is mixed and set between plain papers, the conveyance of the recording sheet is controlled using a device for detecting the kind of the recording sheet and storing / comparing the recording sheet detection information. An example of such a case will be described.
Similar to Embodiments 1 and 2, this inkjet paper is a coated paper in which the surface layer is coated with a coating material having a softening temperature lower than the set temperature of the fixing roller. As in the second embodiment, the first sheet of the sheet feeding tray 1 is a plain sheet, and the first sheet of the sheet feeding tray 1 is a plain sheet.
An inkjet paper was set on the third sheet, plain paper was set on the third sheet, inkjet paper was set on the fourth sheet, inkjet paper was set on the fifth sheet, and an image was recorded. Further, in this embodiment, two recording sheets T can be stored in the temporary storage tray 6 of the separation conveyance path 5.

In the image forming apparatus of the third embodiment, in the downstream of the size detecting device 3 in the conveying direction of the recording sheet T,
A recording sheet type detecting device 3 is provided upstream of the recording sheet discriminating means 4. Recording sheet type detection device 11
Includes a paper thickness detection device that detects the paper thickness of the recording sheet T, a glossy paper detection device that detects whether the recording sheet T is glossy paper, and a front and back surface detection device that determines whether the front and back surfaces are the same. (Neither is shown). As a paper thickness detection device, LE
A light emitting element such as D that projects irradiation light onto the recording sheet T, the reflected light is received by a light receiving element that uses a position detection element, and the paper thickness is detected from the output thereof. Further, it is also possible to use a roller guide that is provided with a reflecting surface that changes according to the thickness of the recording sheet T conveyed by the conveying roller of the conveying device 16 and that detects the positional variation amount of the reflecting surface with a reflection type sensor. . It is also possible to use a mechanism in which a reflecting surface is provided on a mechanism that swings in a seesaw shape in accordance with the thickness of the recording sheet T to be conveyed, and a position variation amount of the reflecting surface is detected by a reflection type position sensor. Further, it is also possible to use one in which two sets of optical sensors are arranged at different angles at the same point on the paper transport path and the paper thickness is detected from the detection time difference of the recording sheet T. Further, the glossy paper detecting device is a recording sheet T
A light-emitting element that makes the light incident at a predetermined angle and a light-receiving element that receives the reflected light that is the light projected from this light-emitting element reflected on the surface of the paper are used to detect the amount of diffuse reflected light and specular reflected light. To use.

FIG. 4 shows a flowchart of the third embodiment.
When image formation is started, the first sheet of the set recording sheet is picked up and conveyed to the coated paper discriminating apparatus 2.
Similar to the first embodiment, the coated paper discriminating apparatus 2 discriminates that the first recording sheet T is not the coated paper, and conveys the recording sheet T to the fixing section via the transfer section through the normal conveyance path. And perform normal image recording.

Next, the second recording sheet is picked up and conveyed to the coated paper discriminating apparatus 2. Coated paper discriminating device 2
In the same manner as in Example 1, the recording sheet T is determined to be coated paper and is conveyed to the recording sheet type detection device 11.
Next, the recording sheet type detection device 3 detects the size, paper thickness, whether or not the second recording sheet T is glossy paper, and whether or not the front and back surfaces are the same. Next, the recording sheet T is conveyed to the recording sheet discriminating means 4 and is discriminated to be wound around the fixing roller by the recording sheet discriminating means 4, as in the first embodiment. Therefore, the conveyance control device conveys the recording sheet T to the separation conveyance path 5 and stores it in the temporary storage tray 6 so as not to convey the recording sheet T to the heating fixing roller.

Similarly, the third recording sheet is conveyed to the coated paper discriminating apparatus 2 and discriminated as plain paper. Therefore,
Similar to the first sheet, a normal image is recorded and then ejected.

Then, the fourth recording sheet is conveyed,
For example, as a method of detecting the paper thickness of the recording sheet, a reflective photo interrupter is used, and from the detection output,
The paper thickness information and the transparent sheet / non-transparent sheet can be discriminated. The detection information is, for example, a paper thickness of 105 μ.
It is determined that m, glossy paper, and front and back are different. Then, these pieces of detection information are stored in the recording sheet detection information storage device. Next, the recording sheet T is heat-treated by the heat treatment device 41, and the softening determination device 42 detects the surface states of the heating portion and the sadly heating portion of the recording sheet, as in the second embodiment. It is determined that it will wind up. Therefore, the conveyance control unit conveys the recording sheet T to the separation conveyance path 5 and stores it in the temporary storage tray 6 so that the recording sheet T is not conveyed to the fixing roller T in the heated state.
Further, the detection information recording apparatus stores the surface state detection data of the recording sheet T and the fact that it is determined that the recording sheet is a recording sheet wound around the fixing roller.

Similarly, the third recording sheet is conveyed, and the recording sheet type discriminating means 3 discriminates it as plain paper. Therefore, as in the case of the first sheet, the normal image is recorded, and then the sheet is ejected.

Next, the fourth recording sheet is conveyed,
Like the second sheet, it is determined to be coated paper. Further, the recording sheet type discrimination means 3 detects the recording sheet information such as the size of the second recording sheet T, the thickness of the recording sheet, whether it is glossy paper, and whether the front and back surfaces are the same. . Here, the detection information stored in the fourth recording sheet T, which is determined to be coated paper, and the detection information stored in the previously conveyed second coating paper are compared by the detection information comparing means, and both are detected. When the information is the same, it is determined that the recording sheets are the same type. And
Based on the information stored in the detection information recording device that the second recording sheet is determined to be the recording sheet that winds around the fixing roller, the fourth recording sheet is also transferred to the fixing roller when the fourth recording sheet is conveyed to the fixing roller. It is determined to be wrapped. Therefore, the conveyance control means causes the recording sheet T to
The recording sheet T is conveyed to the separation conveyance path 5 and stored in the temporary temporary storage tray 6. It should be noted that by obtaining a larger amount of information detected by the recording sheet information detecting means, it is possible to improve the comparison accuracy of the recording sheets.

Next, like the fourth recording sheet, the fifth recording sheet is also discriminated as coated paper. In addition, the recording sheet type determining unit 3 provides the recording sheet information indicating the size of the second recording sheet T, the thickness of the recording sheet, whether it is glossy paper, and whether the front and back surfaces are the same. To detect. Here, the information stored in the recording sheet information detecting means and the detection information of the fifth recording sheet T are compared, and it is determined that they are the same type of recording sheet. Further, when the fifth recording sheet is also conveyed to the fixing roller 8, it is determined that the fifth recording sheet is wound around the fixing roller 8. Therefore, the conveyance control unit separates the recording sheet T from the conveyance path 5 without performing the surface heating process.
Transport to. Since the two recording sheets have already been stored in the temporary storage tray 6 of the separation conveyance path 5, the fifth recording sheet stops on the conveyance path.

Here, as in the second embodiment, the fixing temperature control device controls to lower the temperature of the fixing roller. Then, when the temperature becomes equal to or lower than the specified temperature, the recording sheet stored in the temporary storage tray 6 of the separation / conveyance path is discharged. Then, the stopped recording sheet is discharged onto the transport path 5. After the three recording sheets have passed the fixing roller, the fixing temperature control device returns the temperature of the fixing roller to the original fixing temperature.

(Embodiment 4) An embodiment in which the electrophotographic coated paper and the inkjet paper are mixed and set will be described. The first sheet of the sheet feed tray 1 was coated with electrophotographic coated paper, and the second sheet was set with inkjet paper to form an image.
Here, the electrophotographic coated paper is a coated paper having a surface layer coated with a coating material having a softening point higher than the heat fixing temperature of the fixing device. The softening temperature of the coating material applied to the surface layer of the inkjet paper is lower than the set temperature of the fixing roller.

The flowchart of the fourth embodiment is the same as the flowchart of the first embodiment. When image formation is started,
The first set recording sheet is picked up and conveyed to the coated paper discriminating apparatus 2. The coated paper discriminating apparatus 2 discriminates that the recording sheet T is coated paper and conveys it to the size detecting apparatus 3. Next, the size detection device 3 detects the size of the second recording sheet T. Next, the recording sheet T
Is conveyed to the heat treatment device 41 of the recording sheet discrimination means 4. The heat treatment device 41 heat-treats the right peripheral surface of the recording sheet T in the same manner as in the first embodiment.
The heated recording sheet T is conveyed to the softening determination device 42. In the softening determination device 42, the surface state detection device detects the surface states of the heated portion and the non-heated portion of the recording sheet T.
When the detection results of both are compared and the difference is discriminated, it is considered that the surface layer of the first recording sheet T is not softened or melted by heating. Therefore, the recording sheet T is transported to the fixing unit via the transfer unit in a normal transport system path. In this way, normal image recording is performed on the first electrophotographic coated paper.

Then, as with the first recording sheet, the second recording sheet is picked up and the recording sheet T is conveyed to the coated paper discriminating apparatus 2. The coated paper discriminating apparatus 2 discriminates that the recording sheet T is coated paper and conveys it to the size detecting apparatus 3. Then, the size detection device 3 detects the size of the second recording sheet T. Next, the recording sheet T is conveyed to the heat treatment device 41 of the recording sheet discrimination means 4. The heat treatment device 41, based on the size information detected above,
The right peripheral surface of the recording sheet T is heat-treated. The heat-treated recording sheet T is conveyed to the softening determination device 42. In the softening determination device 42, the surface state detection device detects the surface states of the heated portion and the non-heated portion of the recording sheet T.
When the detection results of both are compared and the difference is determined, it is considered that the surface layer of the second recording sheet T is softened or melted by heating. From this, it is determined that when the recording sheet T is conveyed to the heating fixing device, the surface of the recording sheet is softened and is wound around the fixing roller 8. Therefore, the conveyance control device immediately stops the recording sheet T on the conveyance path so as not to convey the recording sheet T to the heating fixing roller 8. Therefore, the recording sheet T stops on the transport path after passing through the recording sheet determination means 4. Then, after the conveyance of the recording sheet is stopped, the user is informed by the display of the operation unit and a request for taking out the stopped recording sheet is requested.

The second recording sheet is the fixing roller 8.
When it is determined that the first recording sheet is wrapped around, the image recording of the first recording sheet is still being performed, and the sheet has not been discharged from the apparatus. Therefore, the first recording sheet T, which is a recording sheet in the downstream process from the second recording sheet, continues image recording and is discharged after the recording is completed.

As described above, according to the image forming apparatus of the present embodiment, it is possible to determine the heat resistance of the recording sheet to the fixing device and prevent the recording sheet from winding around the fixing roller. Further, the recording sheet discriminating means 4 includes a heat treatment device 41 for heating a part of the recording sheet T, and a softening discriminating device 42 for discriminating whether or not the heating portion heated by the heat treatment device 41 has been softened. Softening discrimination device 42
When it is determined that the heating portion of the recording sheet T has softened, the recording sheet T is determined to wind around the fixing roller 8. As described above, it is determined whether or not the heating portion heated by the heat treatment device 41 is softened. When the heating portion is softened, the coating material that is softened by the heat of the fixing roller 8 is applied, and the recording is performed. It is determined that the sheet T is wound around the fixing roller. Then, by controlling the recording sheet T so as not to be conveyed to the heating fixing device, it is possible to prevent the recording sheet coated with the coating material that is softened by the heat of the fixing roller 8 from winding around the fixing roller. . Further, the heat treatment device 41 includes a heating unit that heats a part of the recording sheet T by bringing a heating element into contact therewith, and the softening determination device 42 includes a surface state detection device that detects the surface state of the recording sheet T. The device 41 heats a part of the recording sheet T at a temperature set based on the surface temperature of the fixing roller 8, and the surface state detection device detects the surface states of the heated portion and the non-heated portion of the recording sheet T and heats them. It is determined whether or not the heating portion of the recording sheet T is softened by comparing the surface state detection results of the heating portion and the non-heating portion. As described above, from the change in the surface condition of the portion heated above the surface temperature of the fixing roller 8, it is determined whether or not the coating material having the softening temperature lower than the surface temperature of the fixing roller 8 is applied, and the fixing roller is determined. It is possible to determine whether or not it is wound around 8. In addition, the coated paper discriminating device 2 is disposed upstream of the heat treatment device 41 in the transport direction of the recording sheet T and discriminates whether or not the recording sheet T has a coating layer on the surface thereof. Only when the engineering paper discriminating apparatus 2 discriminates that the recording sheet T is coated paper, a part of the recording sheet T is heated by the heat treatment device of the recording sheet discriminating means 4. Whether or not the recording sheet is coated paper is detected, and if it is not coated paper, the heating process is not performed, so the process is simplified. Further, it is possible to prevent the deterioration of the recorded image due to the influence of the change in the water content on the surface of the recording sheet due to the partial heating. Further, when the recording sheet determination means 4 determines that the recording sheet T is wound around the fixing roller 8, the conveyance control device stops the conveyance of the recording sheet T, or stops the conveyance after conveying the recording sheet T to a predetermined position. Control. As a result, the recording sheet which is determined to be wound around the fixing roller 8 is not conveyed to the heating fixing device. When the recording sheet determination means 4 determines that the recording sheet T is wound around the fixing roller 8, the conveyance control device determines that the recording sheet located downstream of the recording sheet determined by the recording sheet determination means is in the recording sheet conveyance direction. The image forming operation is continued, and the recording sheet on the upstream side of the recording sheet in the conveying direction of the recording sheet is controlled to be stopped or stopped after being conveyed to a position designated in advance. As described above, since the image recording of the recording sheet conveyed to the downstream process from the recording sheet is continuously performed, the image recording of the recording sheet can be normally performed, and the waste of the recording sheet can be suppressed. A recording sheet separating / conveying path 5 that separates and conveys the recording sheet is provided downstream of the recording sheet discriminating unit 4 in the recording sheet conveying direction and upstream of a transfer portion where the toner image is transferred to the recording sheet T. And the conveyance control device causes the recording sheet determination means 4 to perform recording sheet T
When it is determined that the recording sheet T is wound around the fixing roller 8, the recording sheet T is conveyed to the recording sheet separation conveyance path 5, and when it is determined that the recording sheet is not wound around the fixing roller 8, the recording sheet T is transferred to the transfer unit. Control to transport to. In this way, the separation / conveyance path 5 is provided to store the recording sheet which is determined to be wound around the fixing roller. Therefore, when the user takes out the recording sheet determined to be wound around the fixing roller 8 from the inside of the machine, the recording sheet is stored in the same place, so that the operability is good. Further, the recording sheet T is provided with a temporary storage tray 6 for temporarily storing the recording sheets conveyed to the recording sheet separating / conveying path 5, and the recording sheet discriminating means 4 determines that the recording sheet T is wound around the fixing roller 8 by the conveying control device. Is conveyed to the recording sheet separating and conveying path 5 and stored in the temporary storage tray 6. By thus providing the separation / conveyance path 5, the recording sheet is temporarily stored. Therefore, the processing on the recording sheet on the upstream side in the recording sheet conveying direction can be continuously performed without stopping the apparatus. Further, when the user takes out the recording sheets which are determined to be wound around the fixing roller from the inside of the machine, they are collectively stored in the same place, so that the operability is good. Further, a fixing temperature control device for controlling the temperature of the fixing roller is provided, and when the conveyance control device conveys the recording sheet to the separation conveyance path, the conveyance of the next recording sheet is stopped and the fixing temperature control device causes the fixing roller to rotate. After the temperature of the fixing roller 8 becomes lower than the preset temperature, the conveyance control device controls to discharge the recording sheet T from the separation conveyance path 5 to the outside of the machine via the fixing device. When the recording sheet is temporarily stored in the separation conveyance path, it is determined that the temperature of the fixing roller 8 is lowered and the sheet is discharged after the fixing temperature is lowered, so that the recording sheet is automatically wound around the fixing roller. The recording sheet can be discharged. Further, the recording sheet type detecting device 11 arranged upstream of the recording sheet discriminating means and discriminating the type of the recording sheet, the detection result of the recording sheet type discriminating device 11 and the recording sheet discriminating means fixes the recording sheet T. A recording device that stores a result of determination whether or not the roller 8 is wound, and a detection result of detecting the type of the recording sheet T by the recording sheet type detection device 11 and the recording sheet by the recording sheet determination means 4 is a fixing roller. The result of determining whether or not the sheet is wound around is stored in the storage device, the type of the recording sheet newly conveyed by the recording sheet type detection device 11 is detected, and the detection result is stored as the detection result stored in the storage device. If they match with each other, the recording sheet discriminating means 4 does not discriminate whether or not the newly conveyed recording sheet is wound around the fixing roller. As consistent with the determination result stored in the device, to control the conveyance of the recording sheet which has been newly conveyed by the transfer control device. The detection information of the recording sheet type of the recording sheet that is determined to be wound around the fixing roller and the determination result are stored and compared with the detection information of the recording sheet type of the newly conveyed recording sheet to perform recording. When the sheet type detection information matches, the determination result is also stored. As a result, it is possible to determine whether or not the recording sheet is wound around the fixing roller based on the detection information without performing the heating process on the surface of the recording sheet. Further, the recording sheet type detection device 11 includes a paper thickness detection device for detecting the paper thickness of the recording sheet,
It is provided with a glossy paper detection device for detecting whether or not it is glossy paper and a front and back detection device for determining whether or not the front and back surfaces are the same. As a result, it is possible to determine whether the recording sheet types match. Further, a size detecting device 3 for detecting the size of the recording sheet is provided on the upstream side of the recording sheet discriminating means 4, and the heat processing means 41 causes the peripheral portion of the recording sheet based on the size information of the recording sheet detected by the size detecting means 3. Is configured to be heated. in this way,
Since the peripheral portion of the recording sheet is heated, it is possible to minimize the deterioration of the recorded image due to the influence of the change in the amount of water on the surface of the recording sheet. Further, a fixing temperature detecting means 9 for detecting the surface temperature of the fixing roller is provided, and the heating temperature of the recording sheet by the heat treatment device 41 is set based on the surface temperature of the fixing roller 8 detected by the fixing temperature detecting means 9. By constantly detecting the surface temperature of the fixing roller and feeding back the detection information, the heating temperature of the recording sheet heating device can be adjusted accurately. Therefore, it is possible to accurately determine whether or not the fixing roller is wound around.
Further, the heating time for the recording sheet by the heat treatment device 41 is set based on the linear velocity of the recording sheet. By setting the heating time for the recording sheet T for each linear velocity, the heating process can be performed under the same conditions as the time when the recording sheet T is nipped by the fixing roller 8. Therefore, it is possible to accurately determine whether or not the fixing roller is wound around. Further, when the recording sheet discriminating means 4 discriminates that the recording sheet T is wound around the fixing roller 8, it is provided with a display means for displaying the discrimination result. When it is determined that the conveyed recording sheet is wound around the fixing roller, it is possible to inform the user that the recording sheet that cannot be used is set and provide information for preventing the recurrence.

[0040]

According to the invention of claims 1 to 15, the recording sheet is prevented from being wound around the fixing device, and
There is an excellent effect that an image can be formed on a recording sheet having heat resistance to the fixing device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to this embodiment.

FIG. 2 is a flowchart of the first embodiment.

FIG. 3 is a flowchart of the second embodiment.

FIG. 4 is a flowchart of a third embodiment.

[Explanation of symbols]

1 Paper tray 2 Coated paper discrimination device 3 size detector 4 Recording sheet discrimination means 5 separation conveyance route 6 Temporary storage tray 7 photoconductor 8 fixing roller 9 Surface temperature detection means 10 Recording sheet type detection device 11 Charging device 12 Exposure equipment 13 Development device 14 Transfer device 15 Cleaning device 16 Paper feeder 17 Conveyor 41 Heat treatment equipment 42 Softening discriminating device

Continued front page    F term (reference) 2H027 DA12 DC02 DC10 DE02 DE07                       EA11 ED16 EE05 EE08 GA30                       GB10                 2H033 AA47 BB00 CA07 CA16 CA17                       CA27 CA38                 2H072 AA09 AA16 AA23 AB20 AB21

Claims (15)

[Claims] 1. An image forming apparatus in which a toner image formed on an image carrier is transferred to a recording sheet, and the toner image carried on the recording sheet is thermally fixed by a fixing device having a fixing roller. A recording sheet discriminating means for discriminating whether or not the recording sheet is wound around the fixing roller by heat fixing of the fixing roller, and a conveyance control device for controlling conveyance of the recording sheet are provided, and the recording sheet discriminating means performs the recording sheet. When it is determined that the recording sheet is wound around the fixing roller, the image forming apparatus is controlled by the conveyance control device so that the recording sheet is not conveyed to the heating fixing device. 2. The image forming apparatus according to claim 1, wherein the recording sheet discriminating means softens the heat treatment device for heating a part of the recording sheet and the heating portion heated by the heat treatment device. An image forming apparatus comprising: a softening determination device that determines whether the recording sheet is wound around the fixing roller when the softening determination device determines that the heating portion of the recording sheet has softened. apparatus. 3. The image forming apparatus according to claim 2, wherein the heat treatment device includes a heating section for heating a part of the recording sheet by bringing a heating element into contact therewith, and the softening discriminating device has a surface state of the recording sheet. And a heating unit for heating a part of the recording sheet at a temperature set based on the surface temperature of the fixing roller, and the heating unit for the recording sheet by the surface condition detecting unit. And an unheated surface state of the recording sheet are detected, and the surface state detection results of the heated portion and the unheated portion are compared to determine whether or not the heated portion of the recording sheet is softened. apparatus. 4. The image forming apparatus according to claim 2, wherein the recording sheet is arranged on the upstream side of the heat treatment apparatus in the conveying direction of the recording sheet, and the recording sheet is a coated paper having a coating layer on its surface. A part of the recording sheet by the heat treatment device of the recording sheet discriminating means only when the coated paper discriminating device discriminates that the recording sheet is the coated paper. An image forming apparatus, wherein the image forming apparatus is characterized by heating. 5. The image forming apparatus according to any one of claims 1 to 4, wherein when the recording sheet determination means determines that the recording sheet winds around a fixing roller, the conveyance control device conveys the recording sheet. An image forming apparatus, which is controlled to stop or to stop the conveyance after conveying to a predetermined position. 6. The image forming apparatus according to claim 1, wherein when the recording sheet discriminating means discriminates that the recording sheet winds around a fixing roller, the conveyance control device discriminates by the recording sheet discriminating means. The recording sheet on the downstream side of the determined recording sheet in the recording sheet conveyance direction continues the image forming operation, and stops the conveyance of the recording sheet on the upstream side of the recording sheet in the recording sheet conveyance direction, or
An image forming apparatus that controls to stop the conveyance after the conveyance to a position designated in advance. 7. The image forming apparatus according to claim 1, wherein the toner image is transferred to the recording sheet on the downstream side of the recording sheet discriminating means in the recording sheet conveying direction. Upstream of the section,
A recording sheet separating / conveying path for separating and conveying the recording sheet is provided, and when the conveying control device determines that the recording sheet is wound around the fixing roller by the recording sheet discriminating means, the recording sheet is separated and conveyed. An image forming apparatus characterized in that, when the recording sheet is conveyed to a path and it is determined that the recording sheet is not wound around a fixing roller, the recording sheet is controlled to be conveyed to the transfer section. 8. The image forming apparatus according to claim 7, further comprising a temporary storage section for temporarily storing the recording sheet conveyed to the recording sheet separating / conveying path, wherein the conveyance control device fixes the recording sheet by the recording sheet discriminating means. An image forming apparatus characterized in that a recording sheet determined to be wound around a roller is conveyed to a recording sheet separating / conveying path and stored in the temporary storing section. 9. The image forming apparatus according to claim 7, further comprising a fixing temperature control device for controlling the temperature of the fixing roller, and when a recording sheet is conveyed to the separation conveyance path by the conveyance control device, the next recording sheet is conveyed. And the temperature of the fixing roller is lowered by the fixing temperature control device so that the temperature of the fixing roller becomes equal to or lower than a preset temperature, the feeding control device removes the recording sheet from the separating and feeding path. An image forming apparatus characterized in that control is performed so that the sheet is discharged to the outside of the apparatus via a fixing device. 10. An image forming apparatus according to claim 1, further comprising a recording sheet type detecting device arranged upstream of the recording sheet discriminating means in the recording sheet conveying direction and discriminating the type of the recording sheet. A recording device for storing the detection result of the recording sheet type determination device and the result of determination of whether the recording sheet is wound around the fixing roller by the recording sheet determination means. The detection result of detecting the type of the recording sheet and the result of the determination of whether or not the recording sheet is wound around the fixing roller by the recording sheet determination means are stored in the storage device,
When the type of the recording sheet newly conveyed by the recording sheet type detecting device is detected and the detection result is compared with the detection result stored in the storage device, the recording sheet discriminating means newly detects It is determined that the recording sheet that has been conveyed to the recording sheet does not wrap around the fixing roller and that the recording sheet is newly conveyed by the above-mentioned conveyance control device, assuming that it matches the determination result stored in the storage device. An image forming apparatus that controls conveyance of a sheet. 11. The image forming apparatus according to claim 10, wherein the recording sheet type detecting device detects a paper thickness of the recording sheet and a glossy paper detecting device detects whether the recording sheet is glossy or not. An image forming apparatus, comprising: a front and back detection device that determines whether the front and back surfaces are the same. 12. The image forming apparatus according to claim 2, further comprising a size detection device for detecting the size of the recording sheet upstream of the recording sheet discriminating means in the recording sheet conveying direction. An image forming apparatus, wherein the heat treatment device is configured to heat a peripheral portion of the recording sheet based on size information of the recording sheet detected by the device. 13. The image forming apparatus according to claim 2, further comprising fixing temperature detecting means for detecting the surface temperature of the fixing roller, and based on the surface temperature of the fixing roller detected by the fixing temperature detecting means. An image forming apparatus, wherein a heating temperature of the recording sheet by the heat treatment apparatus is set. 14. The image forming apparatus according to claim 2, wherein the heating time for heating the recording sheet by the heat treatment apparatus is set based on the linear velocity of the recording sheet. Forming equipment. 15. The image forming apparatus according to claim 1, further comprising display means for displaying the discrimination result when the recording sheet discrimination means discriminates that the recording sheet winds around a fixing roller. An image forming apparatus characterized by the above.