JP2008049667A - Image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dissolve the color drift by two or more solid scan type optical writing units in which the element pitch differs. <P>SOLUTION: The image formation device comprises solid scan type optical writing units prepared for every color and having a configuration in which each of them has two or more light modulation devices arranged in one direction, and a control part which has a capability which controls the optical writing for every color by each of the solid scan type optical writing units, wherein in the solid scan type optical writing units for every color, the solid scan type optical writing unit having the shortest length in a longitudinal direction of a light modulation device arrangement is arranged making the longitudinal direction of the light modulation device arrangement agree with a main scan direction, and the solid scan type optical writing unit having the length in a longitudinal direction of the light modulation device arrangement longer than others is arranged to lean to a sub scan direction so that the length of a main scan direction may become same as that of other solid scan type optical writing units, and wherein the control part controls so that each light modulation device may perform the light modulation based on an image data in which the light modulation should be carry out essentially responding to the drift in a sub scan direction of each light modulation device of the leaned solid scan type optical writing unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine and a printer, and more particularly to an image forming apparatus having a solid scanning optical writing device that performs exposure for each color by light emission lighting driving or light modulation.

  In an image forming apparatus such as a copying machine or a printer, an electrostatic latent image is formed according to exposure based on image data, the electrostatic latent image is developed to form a toner image, and the toner image is transferred onto a recording sheet. There is something to do.

  In the image forming apparatus that forms an electrostatic latent image / toner image by performing such exposure, the image carrier is irradiated with laser light in the main scanning direction, and the image carrier is in the main scanning direction. There is a type that irradiates light from a solid-state scanning optical writing device having a longitudinal direction of.

Here, the solid-state scanning optical writing device includes both a device that performs light emission lighting driving such as an LED array, and a device that combines a continuous lighting light source with a light modulation element.
Further, in such an image forming apparatus, it is necessary to perform exposure for each color in order to form a color image. Here, if the exposure position for each color is deviated, it will ultimately cause the image to deteriorate as a color deviation. The exposure position shift may be caused by various factors such as an attachment error of the solid-state scanning optical writing apparatus for each color and a shift due to the accuracy of the solid-scanning optical writing apparatus itself.

Note that in an image forming apparatus using a solid scanning optical writing device, a color shift caused by a shift of the solid scanning optical writing device is described in units of one pixel as described in Patent Document 1 below. It is possible to cope by shifting the image data.
Japanese Patent Laying-Open No. 2005-96364 (first page, FIG. 1)

  According to the invention described in Patent Document 1 described above, the storage unit that stores the shift is provided, and the image data in the main scanning direction is shifted in units of one pixel in accordance with the shift, thereby causing the color shift in the main scanning direction. It is possible to eliminate

  By the way, the element pitch of the solid scanning optical writing device having an element density of 600 dpi (600 dots / 25.4 mm) is 42.33 μm, whereas the element density is 1200 dpi (1200 dots / 25.4 mm). The element pitch of the type optical writing device is 21.17 μm.

  That is, one light modulation element of 600 dpi does not coincide with two light modulation elements of 1200 dpi. The error accumulation is small for several elements, but in a solid scanning optical writing device that forms an image on A3 size paper, it is 7679 elements in the case of 600 dpi, and 15358 elements in the light modulation element of 1200 dpi. A shift of 0.077 mm (= 77 μm) occurs due to the difference in element pitch described above.

  As a result, when an image is formed at 600 dpi, a color shift of two pixels occurs, and the image quality is significantly deteriorated. In addition, since errors are gradually accumulated due to the difference in element pitch, there is a problem that cannot be dealt with by the data shift in units of pixels in the cited reference 1 described above.

  The present invention has been made in view of the above problems, and is an image using a solid-state scanning optical writing device for each color, which is an aggregate of light modulation elements that are subjected to light modulation to perform exposure for each color. An object of the present invention is to realize an image forming apparatus capable of eliminating the color misregistration that occurs when a plurality of solid-state scanning optical writing apparatuses having slightly different light modulation element pitches are used in the forming apparatus.

That is, the present invention for solving the above problems is as described below.
(1) The invention according to claim 1 is provided for each color, each of which has a configuration in which a plurality of light modulation elements are arranged in one direction, and each of the solid scanning types A control unit having a function of controlling optical writing for each color by the optical writing device, and among the solid scanning optical writing devices for each color, the length in the longitudinal direction of the light modulation element array is the first. Regarding a short solid scanning optical writing device, a solid scanning optical writing device in which the longitudinal direction of the light modulation element array is aligned with the main scanning direction and the length of the light modulation element array longitudinal direction is longer than the others. The main scanning direction is tilted in the sub-scanning direction so that the length in the main scanning direction is the same as that of the other solid-scanning optical writing apparatus, and the control unit controls each light of the tilted solid-scanning optical writing apparatus Depending on the deviation of the modulation element in the sub-scanning direction, each light modulation element changes to the image data that should be originally light modulated. Controls to perform Zui light modulation, it is an image forming apparatus according to claim.

  (2) The invention according to claim 2 is that, among the solid-state scanning optical writing devices for each color, the solid-state scanning optical writing device having a longer length in the longitudinal direction of the optical modulation element array than the others is an optical modulation device. The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed so as to be inclined in the sub-scanning direction with respect to an end in the arrangement longitudinal direction.

  (3) The invention according to claim 3 is that the solid scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array than the others among the solid scanning optical writing devices for the respective colors. The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed so as to be inclined in the sub-scanning direction with respect to a center position in the arrangement longitudinal direction.

According to each of the above inventions, it is possible to obtain the effects listed below.
(1) In the first aspect of the invention, a solid-state scanning optical writing device having a configuration in which a plurality of light modulation elements are arranged in one direction, and a function of controlling optical writing for each color When the image forming is performed using the control unit, the solid-state scanning optical writing apparatus having the shortest length in the longitudinal direction of the light modulation element array is made to match the longitudinal direction of the light modulation element array in the main scanning direction. For the solid scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array than the others, the length in the main scanning direction is the same as that of the other solid scanning optical writing devices. Based on the image data that each light modulation element should originally light modulate according to the displacement of each light modulation element in the tilted solid-state scanning optical writing device in the sub-scanning direction. Control to perform light modulation.

  As described above, the solid scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array than the other by the tilted arrangement in the sub-scanning direction has a different length in the main scanning direction. It becomes the same as the apparatus, and the deviation in the main scanning direction is eliminated.

  In addition, regarding the deviation in the sub-scanning direction newly generated in the tilted solid scanning optical writing apparatus at this time, by performing control to perform optical modulation with image data that should be originally optically modulated in accordance with the deviation, Deviations in the sub-scanning direction are also eliminated.

  Thereby, it is possible to realize an image forming apparatus capable of eliminating color misregistration that occurs in the case of color image formation using a plurality of solid scanning optical writing apparatuses having slightly different light modulation element pitches.

  (2) In the invention according to claim 2, among the solid scanning optical writing devices for each color, the solid scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array than the others is arranged in the main scanning direction. The optical modulators are arranged so as to be inclined in the sub-scanning direction with respect to the end in the longitudinal direction of the light modulation element array so that the length is the same as that of other solid scanning optical writing devices.

  As described above, the arrangement in which the light modulation element array is tilted in the sub-scanning direction with respect to the longitudinal end portion of the light modulation element array makes it possible for the solid scanning optical writing device having a longer length in the main scanning direction than the other solid scanning light. It becomes the same as the writing device, and the end in the main scanning direction (terminal side) comes to be aligned with other solid scanning optical writing devices, and the deviation in the main scanning direction is eliminated.

  In addition, regarding the deviation in the sub-scanning direction newly generated in the tilted solid scanning optical writing apparatus at this time, by performing control to perform optical modulation with image data that should be originally optically modulated in accordance with the deviation, Deviations in the sub-scanning direction are also eliminated.

  Thereby, it is possible to realize an image forming apparatus capable of eliminating color misregistration that occurs in the case of color image formation using a plurality of solid scanning optical writing apparatuses having slightly different light modulation element pitches.

  (3) In the invention described in claim 3, among the solid scanning optical writing devices for each color, the solid scanning optical writing device whose length in the longitudinal direction of the light modulation element array is longer than the others is In order to have the same length as other solid scanning optical writing devices, the optical modulators are arranged so as to be inclined in the sub-scanning direction with reference to the center position in the longitudinal direction of the light modulation element array.

  As described above, with the tilted arrangement in the sub-scanning direction with respect to the main scanning center position, the solid scanning optical writing device having a longer length in the main scanning direction than the other solid scanning optical writing devices. The difference in the main scanning direction is eliminated.

  In addition, regarding the deviation in the sub-scanning direction newly generated in the tilted solid scanning optical writing apparatus at this time, by performing control to perform optical modulation with image data that should be originally optically modulated in accordance with the deviation, Deviations in the sub-scanning direction are also eliminated.

  Thereby, it is possible to realize an image forming apparatus capable of eliminating color misregistration that occurs in the case of color image formation using a plurality of solid scanning optical writing apparatuses having slightly different light modulation element pitches.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below in detail with reference to the drawings.
It should be noted that even if the image forming apparatus (copying apparatus) has a function of reading and copying the contents of a copy object as image information by a document reading section (scanner), the image forming apparatus does not have a document reading section (scanner). Even so, the present invention can be applied. The present invention can also be applied to an image forming apparatus such as a multifunction machine having a facsimile function.

<First Embodiment>
First, the basic components of the present embodiment will be described with reference to FIG. 1, and then the mechanical configuration of the overall configuration of the apparatus to which the image forming apparatus of the embodiment is applied will be described with reference to FIGS.

<Electrical configuration of image forming apparatus>
First, the electrical configuration of the image forming apparatus will be described by function with reference to FIG. Here, the image of the original is read in color (R, G, B) to generate image data, the image processing unit performs image processing on the image data, and the image forming unit forms an image based on the image data. An image forming apparatus that executes is used as a specific example of this embodiment. Here, an image forming apparatus that forms an image with four colors (Y, M, C, K) of an electrophotographic system is used as a specific example.

  The image forming apparatus 100 according to this embodiment includes a control unit 101 configured by a CPU or the like as a control unit that controls color misregistration in addition to control of the entire image forming apparatus, and image reading that reads an original and generates image data. 110, a scanner processing unit 120 that performs necessary processing such as color conversion on the image data obtained by the image reading unit 110, and various image processing necessary for image formation on the image data generated by the scanner processing unit 120. An image processing unit 130 to be executed, a memory 140 used for image processing in the image processing unit 130, and an LPH control unit 150 that performs light emission lighting driving or light modulation control of an LED print head (LPH) that performs exposure for each color. And the memory 160 for each color used in the control by the LPH control unit 150 for each color and the LPH control unit 150 It comprises an LED print head (LPH) 170 as a light-emitting element array (LED light-emitting element array) for each color, which is an aggregate of LED light-emitting elements that are exposed for each color by being driven or light-modulated. Yes.

  In the specific example shown in this embodiment, the image reading unit 110 generates RGB image data by reading RGB, and the scanner processing unit 120 converts the RGB image data into YMCK image data according to the color of image formation. Converted.

  Further, in this embodiment, as a specific example of a light emitting element that performs exposure for each color, an LED is used, and light emission lighting driving or light modulation is performed for each element by on / off control such as light emission / non-light emission. What we do is used as a specific example.

  In this embodiment, the LPH 170 is an example of the solid scanning optical writing device in the claims, and is provided for each color, and each has a configuration in which a plurality of light modulation elements are arranged in one direction. It is. In addition, as the solid-state scanning optical writing device, it is possible to use a continuous lighting light source combined with a light modulation element.

  Further, in this embodiment, the control unit 101 and the LPH control unit 150 constitute a control unit in the claims, and has a function of controlling optical writing by each solid-state scanning optical writing device. A function of controlling each light modulation element to perform light modulation based on image data that should be originally light modulated in accordance with the displacement of each light modulation element of the tilted solid-state scanning optical writing device in the sub-scanning direction. Have.

In the following description of the embodiments, the light emission lighting driving of the light emitting element or the light modulation of the light modulation element is generically called light modulation.
<Mechanical configuration of image forming apparatus>
Here, the mechanical configuration of the image forming apparatus will be described with reference to FIGS. 2 and 3. Here, an image forming apparatus that performs image formation based on image data with the image processing unit and the image forming unit as the center is used as a specific example of this embodiment. In addition, here, an image forming apparatus that forms an image with four colors of an electrophotographic system is used as a specific example.

  In FIG. 2, the image reading unit 110 generates RGB image data by reading RGB, and the scanner processing unit 120 converts the RGB image data into YMCK image data in accordance with the image formation color. The image processing unit 130 executes various types of image processing such as scaling and density setting necessary for image formation on the image data given from the scanner processing unit 120, and the LPH control units 150Y, 150M, 150C, and the like for each color. Image data of each color that has undergone image processing is supplied to 150K.

  The LPH control units 150Y to 150K convert the image data of each color from the image processing unit 130 into exposure data for exposure using the memories 160Y to 160K, and light of the LED print heads (LPH) 170Y to 170K for each color. Modulation control is performed. In this case, the LPH control units 150Y to 150K execute a shift process for shifting exposure data in the sub-scanning direction by an amount corresponding to a shift in the sub-scanning direction, which will be described later, as necessary.

  Then, as shown in FIG. 3, each color LED print head (LPH) 170 </ b> Y to 170 </ b> K exposes the moving photosensitive belt 190 to form an electrostatic latent image of each color. Here, the moving direction of the photosensitive belt 190 is the sub-scanning direction. The main scanning direction is a direction orthogonal to the sub-scanning direction and in which exposure or light modulation is performed for each color line by the LPH 170Y to LPH 170K for each color. However, as will be described later, in this embodiment, in the solid scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array than the others, the longitudinal direction is slightly inclined from the main scanning direction to the sub scanning direction. Be placed.

  This electrostatic latent image is developed by a developing device for each color (not shown) to become a toner image for each color. Since the toner images of the respective colors on the photosensitive belt 190 are formed while being aligned, they become four color toner images. Then, the color toner image on the photosensitive belt 190 is transferred to a recording sheet.

  As for the sub-scanning, the LED print head 170 and the photosensitive belt 190 need only move relatively in the sub-scanning direction. Therefore, it is possible to execute the sub-scanning using other methods or other photoconductors. It is. In addition, the apparatus may be a device in which the LED print head 170 and the photosensitive photosensitive paper on the plane move relatively in the sub-scanning direction and perform recording.

<Description of operation of this embodiment>
In the image forming apparatus as described above, for example, an element density is 1200 dpi (1200 dots / 25.4 mm), an element pitch is 21.17 μm, and a solid scanning optical writing apparatus (see FIG. a)) and an element density of 600 dpi (600 dots / 25.4 mm), an element pitch of 42.33 μm, and a solid scanning optical writing device (FIG. 4B) composed of 7679 elements, The element pitch is not completely 1: 2.

For this reason, there is a deviation of 0.077 mm between the full length (length in the longitudinal direction of the light modulation element array) L ′ and the full length (length in the longitudinal direction of the light modulation element array) L ′.
If the element pitch is completely 1: 2, the element density is 2: 1, so that there is no deviation in the overall length. FIG. 4 schematically shows only the light modulation element portion of the solid-state scanning optical writing device.

  Here, in this embodiment, in the image forming apparatus that forms an image with four colors of YMCK, the solid-state optical writing device shown in FIG. 4A is used for YMC, and FIG. 4B is used for K. The case where the solid scanning optical writing device shown is used is used as a specific example.

  In this case, the total length L ′ of the LPH 170K for K is longer than the others, and the total length L of the LPHs 170Y to LPH170C of other colors is short. Therefore, LPH 170Y to LPH 170C shorter than LPH 170K are arranged in the image forming apparatus in a state in which the longitudinal direction of the light modulation element array coincides with the main scanning direction.

  On the other hand, for the LPH 170K having a longer length in the light modulation element array longitudinal direction than the others, the light modulation element array longitudinal direction is set to the main scanning direction so that the length L ″ in the main scanning direction is the same as the other LPH 170Y to LPH 170C. They are arranged slightly tilted in the sub-scanning direction without matching.

  For this reason, for the LPH 170K having a longer length in the longitudinal direction of the light modulation element array, for example, as shown in FIG. 5, a fixing hole 174 is provided in the pedestal portion 173a on one end of the longitudinal direction of the light modulation element array. In addition, an adjustable hole 175 that can be tilted in the sub-scanning direction is provided in the pedestal portion 173b on the other side of the longitudinal end portion of the light modulation element array. It is assumed that screw holes are also provided on the device side (not shown) so as to match the fixing hole 174 and the adjustable hole 175.

Then, the fixing hole 174 side is fixed to the apparatus side via an attachment screw, and the adjustable hole 175 side is inclined with respect to the sub-scanning direction as schematically shown in FIG.
In this case, if the length in the longitudinal direction of the light modulation element array of the solid scanning optical writing device longer than the other is L ′, the solid scanning optical writing device arranged in the sub scanning direction is inclined in the main scanning direction. The length L ″ is L ″ = L ′ · cos θ. That is, by adjusting θ, L ″ is adjusted to be equal to the length L of the other solid scanning optical writing device.

  In the case of the specific example of the solid scanning optical writing device due to the difference in the element pitch as described above, by setting θ to 1.25 °, the above-described deviation of 0.077 mm is eliminated, and L ′ matches L. (See FIG. 7).

  In this case, the length L ″ of the LPH 170K in the main scanning direction is equal to the length L of the other LPH 170Y to LPH 170C in the longitudinal direction of the light modulation element array. The element pitch of the LPH 170K in the main scanning direction is also adjusted. Means that.

  Note that, here, the light modulation element array longitudinal direction is fixed at one end (main scanning direction leading side) and the other end (main scanning direction rear end side) is moved in the sub-scanning direction and tilted. The same adjustment is possible even if the center position in the longitudinal direction of the modulation element array is fixed and both ends in the longitudinal direction of the light modulation element array are moved to the opposite sides of the sub-scanning direction.

  In the above embodiment, the LPH 170K is attached in a state of being tilted in the sub-scanning direction with a screw. However, even if the sub-board on which the LPH 170K is attached is tilted in the sub-scanning direction with respect to the main board. Good. In addition to determining the inclination angle when mounting and fixing, a drive source such as an actuator or a motor and various drive mechanisms may be used so that electrical adjustment is possible.

  By tilting the LPH 170K in the 1.25 ° sub-scanning direction, the difference in the main scanning direction length due to the difference in the element pitch can be absorbed as described above, but a new shift in the sub-scanning direction occurs. become. In the case of the above specific example, if the shift in the sub-scanning direction is H, H = 325 × sin (1.25 °) = 7.0 mm.

  That is, when the LPH 170K is tilted by 1.25 °, the length in the main scanning direction matches that of the other colors, but a shift in the sub-scanning direction occurs, and a main scanning line that is inclined obliquely with respect to K is formed. Will be.

  Therefore, the LPH control unit 150K performs optical modulation according to the exposure data based on the image data that should be originally exposed at the exposure position corresponding to the deviation in accordance with the deviation of the tilted solid scanning optical writing device in the sub-scanning direction. Control is performed.

In this specific example, if the deviation in the sub-scanning direction is 7.0 mm and the element pitch is 21.17 μm, a deviation of 330 dots occurs in the sub-scanning direction.
Since 330/15538 = 46.5, the LPH control unit 150K has N line image data, N-1 line image data, N-2 line for every 46 dots or 47 dots in the main scanning direction. Exposure data is generated from image data shifted line by line, such as line image data.

  In other words, the LPH control unit 150K stores several lines of image data from the image processing unit 130 in the memory 160, and based on the image data that should be originally exposed at the exposure position corresponding to the shift according to the inclination described above. Exposure data is generated.

  FIG. 8 schematically shows how exposure data (FIG. 8B) for the tilted LPH 170K (FIG. 8A) is generated from image data of different lines in this way. Thereby, according to the shift of the tilted light emitting element array in the sub-scanning direction, the light modulation is executed by the exposure data based on the image data to be originally exposed at the exposure position corresponding to the shift.

  When exposure is repeated in the sub-scanning direction with the exposure data generated in this way, finally, an image formation without any deviation in the main scanning direction and no deviation in the sub-scanning direction was made. It becomes a state.

<Other embodiment (1)>
In the above embodiment, the solid-state scanning optical writing device having an element density of 600 dpi (600 dots / 25.4 mm) and an element pitch of 42.33 μm, and an element density of 1200 dpi (1200 dots / 25.4 mm). However, the present invention is not limited to these numerical values and ratios.

  For example, a solid-state scanning optical writing device having an element density of 1200 dpi (1200 dots / 25.4 mm) and an element pitch of 21.17 μm and an element density of 1200 dpi (1200 dots / 25.4 mm) and an element pitch of 21.17 μm. Even when the element density is the same and the element pitches are different, as in the case of mixing a 16 μm solid-state scanning optical writing device, the above embodiment can obtain good results.

<Other embodiment (2)>
In this case, the solid scanning optical writing device is tilted with the color of K with reference to Y to C, and the exposure data is shifted. However, any color is more modulated than the others. What is necessary is just to incline the solid scanning optical writing device whose length in the element array longitudinal direction becomes longer in the sub scanning direction. Due to the element pitch, not only K but also the solid scanning optical writing device of any color between Y and C may be elongated in the longitudinal direction of the light modulation element array.

  In other words, the solid scanning optical writing device having the shortest length in the longitudinal direction of the light modulation element array is disposed in the main scanning direction, and other lengths are set to match the length in the longitudinal direction of the light modulation element array. The solid scanning optical writing device may be tilted according to the difference in length.

  In addition, specific numerical values such as the resolution, element pitch, tilt angle, and numerical value of processing when shifting image data are examples, and the solid scanning optical writing device of other resolutions. It is also possible to configure.

1 is a functional block diagram illustrating an electrical configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a configuration diagram illustrating a mechanical configuration of an image forming apparatus according to an exemplary embodiment of the present invention. 1 is a configuration diagram illustrating a mechanical configuration of an image forming apparatus according to an exemplary embodiment of the present invention. It is explanatory drawing which shows the mode of the element pitch of the image forming apparatus of embodiment of this invention. It is explanatory drawing which shows the mode of the solid scanning optical writing apparatus used with the image forming apparatus of embodiment of this invention. It is explanatory drawing which shows the mode of the element pitch of the image forming apparatus of embodiment of this invention. It is explanatory drawing which shows operation | movement in the image forming apparatus of embodiment of this invention. It is explanatory drawing which shows operation | movement in the image forming apparatus of embodiment of this invention.

Explanation of symbols

101 Control Unit 110 Image Reading Unit 120 Scanner Processing Unit 130 Image Processing Unit 140 Memory 150 LPH Control Unit 160 Memory 170 LPH
190 Photosensitive belt

Claims (3)

A solid-state scanning optical writing device provided for each color, each having a configuration in which a plurality of light modulation elements are arranged in one direction;
A control unit having a function of controlling optical writing for each color by each of the solid scanning optical writing devices,
Of the solid-state scanning optical writing devices for each color, for the solid scanning optical writing device having the shortest length in the longitudinal direction of the light modulation element array, the longitudinal direction of the light modulation element array is made to coincide with the main scanning direction. For the solid scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array than the others, the length in the main scanning direction is the same as that of the other solid scanning optical writing devices. Place it tilted in the scanning direction,
The control unit performs light modulation based on image data that each light modulation element should originally light-modulate according to a shift in the sub-scanning direction of each light modulation element of the tilted solid scanning optical writing device. To control,
An image forming apparatus. Among the solid-state scanning optical writing devices for each color, the solid-scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array is a sub-scan with respect to the end in the longitudinal direction of the light modulation element array. Arranged at an angle in the scanning direction,
The image forming apparatus according to claim 1. Among the solid-state scanning optical writing devices for the respective colors, the solid scanning optical writing device having a longer length in the longitudinal direction of the light modulation element array is a sub-scan with respect to the center position in the longitudinal direction of the light modulation element array. Arranged at an angle in the scanning direction,
The image forming apparatus according to claim 1.

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