Exposure device and image forming apparatus

Abstract

To provide an exposure device capable of maintaining appropriate image quality.SOLUTION: An image forming apparatus includes a panel member 12a which faces a photoreceptor and has a plurality of light emitting elements 41. The exposure device includes a signal output unit 51 that outputs drive signals having different phases, and a drive unit 52 that causes each of the plurality of light emitting elements 41 to individually emit light based on the drive signal. In the panel member 12a, rows of a plurality of light emitting elements 41 arranged in the main scanning direction S are arranged in a plurality of stages in the sub-scanning direction H. The signal output unit 51 outputs drive signals having a phase difference to the respective element arrays. The distance between the adjacent element arrays in the sub-scanning direction H is set based on a phase correction value obtained by multiplying the peripheral speed of the surface of the photoreceptor drum 3 by the phase difference.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an exposure device and an image forming apparatus that include a panel member having a plurality of light-emitting elements. [Background technology]

[0002] Conventionally, electrophotographic image forming apparatuses have been widely used, which form an electrostatic latent image on a photosensitive member using a laser beam or the like, and then develop, transfer, and fix the electrostatic latent image to form an image on paper. In recent years, linear light sources, in which point light sources such as light-emitting elements are arranged in a line, have been used as the light source for exposing the photosensitive member. Furthermore, by arranging multiple light-emitting elements not only in the main scanning direction but also in the sub-scanning direction, the amount of exposure light is increased and pixel density is increased. It is known that when multiple light-emitting elements are simultaneously made to emit light, the inrush current (change) in the drive circuit becomes large, and a technique for reducing the load of current change has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-100479 Summary of the Invention [Problem to be solved by the invention]

[0004] A conventional image forming device includes a light emitting element row including a plurality of light emitting elements arranged continuously along the main scanning direction, a light emitting control unit that outputs drive signals of different phases based on image data in units of light emitting element groups each consisting of a predetermined number of consecutive light emitting elements included in the plurality of light emitting elements, and a drive unit that causes each of the plurality of light emitting elements to emit light individually based on the drive signal.

[0005] In conventional image forming apparatuses, there is a problem that a step occurs in the sub-scanning direction because there is a phase difference based on the drive signal between light emitting element groups. If the step is not eliminated, it will lead to deterioration of image quality, so there is a problem that the number of light emitting element groups and the phase difference are limited.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an exposure device and an image forming apparatus that can prevent step differences from occurring in an image. [Means for solving the problem]

[0007] The exposure device according to the present disclosure is an exposure device comprising a panel member facing a photosensitive member and having a plurality of light-emitting elements, the exposure device comprising: a signal output unit that outputs drive signals of different phases; and a drive unit that causes each of the plurality of light-emitting elements to emit light individually based on the drive signal; when the direction along the rotation axis of the photosensitive member is defined as the main scanning direction and the direction perpendicular to the main scanning direction is defined as the sub-scanning direction, the panel member is arranged in a plurality of rows in the sub-scanning direction, with element rows in which the plurality of light-emitting elements are aligned in the main scanning direction; the signal output unit outputs the drive signal with a phase difference to each of the element rows; and the distance between adjacent element rows in the sub-scanning direction is set based on a phase correction value obtained by multiplying the circumferential speed of the surface of the photosensitive member by the phase difference.

[0008] In the exposure apparatus according to the present disclosure, the plurality of light-emitting elements in the element array may be divided into a plurality of groups, and the signal output unit may be configured to output the drive signal with a phase difference to each of the groups.

[0009] In the exposure device according to the present disclosure, the signal output section may be configured to adjust the phase of the drive signal so that the phase correction value remains constant when the peripheral speed of the surface of the photosensitive member changes.

[0010] In the exposure apparatus according to the present disclosure, the distance between adjacent element rows in the sub-scanning direction may be a value obtained by adding the phase correction value to an integer multiple of the pixel size in the sub-scanning direction.

[0011] The image forming apparatus according to the present disclosure is characterized by including the exposure device according to the present disclosure. [Effects of the Invention]

[0012] According to the present disclosure, among the light-emitting elements, by dividing the group of elements that emit light into stages, appropriately setting the distance between each stage, and controlling the elements to emit light at the appropriate timing, it is possible to obtain the necessary amount of exposure while suppressing inrush current, and to prevent image steps from occurring, thereby avoiding degradation of image quality. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view showing an image forming apparatus according to a first embodiment of the present disclosure. [Figure 2] 1 is a schematic configuration diagram showing an image forming apparatus according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic plan view showing a panel member according to the first embodiment of the present disclosure. [Figure 4] FIG. 4 is a timing chart showing light emission timing of a light emitting element. [Figure 5] FIG. 10 is an explanatory diagram showing an example of an image exposed in a reference example. [Figure 6] FIG. 2 is an explanatory diagram showing an example of an image exposed in the first embodiment of the present disclosure. [Figure 7] FIG. 10 is a schematic plan view showing a panel member according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] (First embodiment) Hereinafter, an image forming apparatus according to a first embodiment of the present disclosure will be described with reference to the drawings.

[0015] FIG. 1 is a schematic cross-sectional view showing an image forming apparatus according to a first embodiment of the present disclosure.

[0016] The image forming device 100 is a multifunction device having a copy function, a scanner function, a facsimile function, and a printer function, and transmits an image of a document read by the image reading device 130 to an external device, and forms an image of a document read by the image reading device 130 or an image received from an external device in color or monochrome on a recording medium such as paper.

[0017] An original transport device 110 that is supported so as to be able to open and close freely is provided above the image reading device 130. The original transport device 110 transports one or more originals one by one. The image reading device 130 scans a scanning optical system 130b to read an original placed on an original placement table 130a, or reads an original transported by the original transport device 110 to generate image data.

[0018] The image forming apparatus 100 is provided with a fixing device 1, a developing device 2, a photosensitive drum 3 (an example of a photosensitive body), a drum cleaning device 4, a charger 5, an intermediate transfer belt device 7, a secondary transfer device 11, an exposure device 12, and a paper feed section 18.

[0019] Image forming apparatus 100 handles image data corresponding to color images using black (K), cyan (C), magenta (M), and yellow (Y), or monochrome images using a single color (e.g., black). Image forming apparatus 100 is provided with four developing devices 2, four photosensitive drums 3, four drum cleaning devices 4, and four chargers 5 for forming four types of toner images, and four image stations Pa, Pb, Pc, and Pd are configured corresponding to black, cyan, magenta, and yellow, respectively.

[0020] The charger 5 uniformly charges the surface of the photosensitive drum 3 to a predetermined potential. The exposure device 12 has a panel member 12a facing the surface of the photosensitive drum 3 and exposes the surface of the photosensitive drum 3 to light to form an electrostatic latent image. The development device 2 develops the electrostatic latent image on the surface of the photosensitive drum 3 to form a toner image on the surface of the photosensitive drum 3. The drum cleaning device 4 removes and collects residual toner from the surface of the photosensitive drum 3. Through the above-described series of operations, a toner image of each color is formed on the surface of each photosensitive drum 3. The distance between the photosensitive drum 3 and the panel member 12a may be set appropriately depending on the resolution of the electrostatic latent image and the light intensity of the panel member 12a. The panel member 12a will be described in detail with reference to FIG. 3, which will be described later.

[0021] The intermediate transfer belt device 7 includes an intermediate transfer roller 6, an endless intermediate transfer belt 71, an intermediate transfer drive roller 72, an intermediate transfer driven roller 73, and a cleaning device 9. Four intermediate transfer rollers 6 are provided inside the intermediate transfer belt 71 so as to form four types of toner images corresponding to each color. The intermediate transfer rollers 6 transfer the toner images of each color formed on the surface of the photosensitive drum 3 onto the intermediate transfer belt 71, which moves around in a circular motion.

[0022] The intermediate transfer belt 71 is stretched over an intermediate transfer drive roller 72 and an intermediate transfer driven roller 73. In the image forming apparatus 100, the toner images of each color formed on the surface of each photosensitive drum 3 are sequentially transferred and superimposed to form a color toner image on the surface of the intermediate transfer belt 71. The cleaning device 9 removes and collects waste toner remaining on the surface of the intermediate transfer belt 71 without being transferred to paper.

[0023] The secondary transfer device 11 sandwiches and transports a sheet of paper transported through the paper transport path 21 in the transfer nip portion TN between the secondary transfer roller 11a and the intermediate transfer belt 71. When the sheet of paper passes through the transfer nip portion TN, the toner image on the surface of the intermediate transfer belt 71 is transferred onto the sheet of paper, and the sheet of paper is transported to the fixing device 1.

[0024] The fixing device 1 includes a fixing belt 31 that rotates around an axis and a pressure roller 32. The fixing device 1 sandwiches a sheet of paper onto which a toner image has been transferred in a nip portion N between the fixing belt 31 and the pressure roller 32, and applies heat and pressure to fix the toner image to the sheet. Although not shown in FIG. 1, the fixing device 1 may include components other than the fixing belt 31 and the pressure roller 32.

[0025] The paper feed unit 18 includes a paper feed cassette that holds recording media (paper) used for image formation, and is provided below the exposure device 12. The paper is pulled out of the paper feed unit 18 by a pickup roller 16 and transported to a paper transport path 21. The paper transported to the paper transport path 21 passes through the secondary transfer device 11 and the fixing device 1, and is then discharged to a paper output tray 19 by a discharge roller 17.

[0026] Conveyance rollers 13, registration rollers 14, and discharge rollers 17 are arranged on paper conveyance path 21. Conveyance rollers 13 facilitate the conveyance of paper. Registration rollers 14 convey paper at a speed equal to the process speed at which an image is formed on the paper. Registration rollers 14 are provided between paper feed unit 18 and secondary transfer device 11, and adjust the timing of paper conveyance so that the toner image is transferred to the paper by secondary transfer device 11. For example, registration rollers 14 wait (temporarily stop) while clamping paper conveyed from paper feed unit 18, and then start conveying the paper at a constant speed in synchronization with secondary transfer device 11.

[0027] When an image is to be formed on the back side of the paper in addition to the front side, the conveying direction of the paper is changed by discharge rollers 17, and the paper is conveyed to reversing conveying path 22. In reversing conveying path 22, the paper is guided up to registration rollers 14 in a reversed state by reversing conveying rollers 15. Image forming apparatus 100 forms an image on the back side of the paper guided to registration rollers 14 in the same manner as on the front side, and discharges the paper to discharge tray 19.

[0028] Fig. 2 is a schematic configuration diagram showing an image forming apparatus according to the first embodiment of the present disclosure. Note that Fig. 2 shows only a portion of the image forming apparatus 100, and other members not shown in Fig. 2 may be included as appropriate.

[0029] The panel member 12a has a plurality of light-emitting elements 41. The light-emitting elements 41 are, for example, organic light-emitting diodes (OLEDs) or LEDs. The signal output unit 51 outputs a plurality of drive signals that are out of phase with each other. The drive unit 52 is, for example, a drive circuit, and causes each of the plurality of light-emitting elements 41 to emit light individually based on the drive signals. The image forming apparatus 100 may be equipped with a CPU that controls the operation of each unit.

[0030] FIG. 3 is a schematic configuration diagram showing a panel member according to the first embodiment of the present disclosure.

[0031] The exposure device 12 is provided with four panel members 12a facing the four photosensitive drums 3, respectively. An exposure device 12 may be provided independently for each photosensitive drum 3, as long as a panel member 12a is provided corresponding to each of the four photosensitive drums 3. The four panel members 12a have substantially the same configuration, and therefore FIG. 3 shows only one panel member 12a. Although not shown, an optical member such as a lens may be disposed between the photosensitive drum 3 and the panel member 12a, so that light emitted from the light-emitting element 41 forms an image on the surface of the photosensitive drum 3. A spacer or the like may be provided to maintain a constant distance between the photosensitive drum 3 and the panel member 12a.

[0032] In the image forming apparatus 100, the axial direction of the rotation axis of the photosensitive drum 3 is parallel to the width direction of the paper on which an image is formed, and the photosensitive drum 3 is configured to rotate around the axis of the rotation axis. The panel member 12a is a rectangular flat plate, and its longitudinal direction (main scanning direction S) corresponds to the axial direction, and its lateral direction (sub-scanning direction H) corresponds to the rotation direction of the photosensitive drum 3.

[0033] In the panel member 12a, element rows (first group Gr1 to fourth group Gr4) in which a plurality of light-emitting elements 41 are arranged in the main scanning direction S are arranged in a plurality of stages arranged in the sub-scanning direction H. In the following, in order to distinguish between the plurality of light-emitting elements 41, the light-emitting elements 41 may be referred to by being numbered d1, d2, ..., d16 in order from one end side (the left end side in FIG. 3) to the other end side (the right end side in FIG. 3) in the main scanning direction S.

[0034] In this embodiment, a plurality of light-emitting elements 41 arranged diagonally with respect to the main scanning direction S constitute one set, and these sets are periodically and repeatedly arranged. Specifically, the plurality of light-emitting elements 41 constituting one set are arranged such that their positions in the sub-scanning direction H are shifted from one end (the upper end in FIG. 3 ) to the other end (the lower end in FIG. 3 ) of the light-emitting elements 41 adjacent to each other in the main scanning direction S as they move toward one side of the main scanning direction S. Then, the plurality of light-emitting elements 41 constituting the next set are again arranged in order from one end to the other in the sub-scanning direction H. The dashed lines H1 to H4 (first to fourth lines) shown in FIG. 3 are parallel to the main scanning direction S, are aligned at regular intervals in the sub-scanning direction H, and indicate their positions in the sub-scanning direction H. In other words, the light-emitting elements 41 arranged on the same line overlap in the sub-scanning direction H.

[0035] In the panel member 12a shown in Fig. 3, the light-emitting element 41 at d1 is arranged on the first line (H1) located at the uppermost end in Fig. 3, the light-emitting element 41 at d2 is arranged on the second line (H2) shifted downward from the first line, the light-emitting element 41 at d3 is arranged on the third line (H3) shifted downward from the second line, and the light-emitting element 41 at d4 is arranged on the fourth line (H4) shifted downward from the third line. The light-emitting elements 41 from d3 onwards are also arranged shifted downward in the same manner, and the light-emitting element 41 at d8 is arranged on the fourth line (H4) located at the lowermost end in Fig. 3.

[0036] The light emitting elements 41 at d5 to d8 are arranged in the same manner as the light emitting elements 41 at d1 to d4, with the light emitting element 41 at d5 being arranged on the first line. The light emitting elements 41 at d6 and onwards are arranged in order shifted downward, with the light emitting element 41 at d8 being arranged on the fourth line. The light emitting elements 41 at d9 to d12 and the light emitting elements 41 at d13 to d16 are also arranged in the same manner as the light emitting elements 41 at d1 to d4.

[0037] That is, the light-emitting elements 41 of d1, d5, d9, and d13 are grouped in a first group Gr1 arranged on the same first line, the light-emitting elements 41 of d2, d6, d10, and d14 are grouped in a second group Gr2 arranged on the same second line, the light-emitting elements 41 of d3, d7, d11, and d15 are grouped in a third group Gr3 arranged on the same third line, and the light-emitting elements 41 of d4, d8, d12, and d16 are grouped in a fourth group Gr4 arranged on the same fourth line. The interval between adjacent lines (step pitch L) corresponds to the distance between adjacent element rows in the sub-scanning direction H. The step pitch L will be described later with reference to FIGS. 4 and 5.

[0038] As shown in FIG. 3, a driver 52 is provided corresponding to each light-emitting element 41, and signal output units 51 are provided corresponding to the plurality of driver units 52. In the configuration shown in FIG. 3, 16 driver units 52 and four signal output units 51 are provided. Specifically, one signal output unit 51 is provided for the four driver units 52 corresponding to the light-emitting elements 41 d1 to d4. Similarly, a signal output unit 51 is provided for each of the four driver units 52 corresponding to the light-emitting elements 41 d5 to d8, the four driver units 52 corresponding to the light-emitting elements 41 d9 to d12, and the four driver units 52 corresponding to the light-emitting elements 41 d13 to d16. Note that the configuration shown in FIG. 3 is an example of the panel member 12a, and the number of signal output units 51 and driver units 52 provided and the manner in which they are connected to the light-emitting elements 41 may be changed as appropriate.

[0039] Although not shown, a switch or the like for switching on / off may be connected to the light emitting element 41, and signal lines or the like for transmitting control signals may be connected to each section. Furthermore, the light emitting element 41 may not only be switched on / off, but also the light intensity or light emission time may be changed by changing the voltage or current, and may be appropriately controlled by a signal input to the drive section 52.

[0040] As described above, in this embodiment, each element column is organized into a group, with first group Gr1 to fourth group Gr4. The signal output unit 51 outputs drive signals with a phase difference to each element column. Next, the relationship between the drive signals output to each group and the operation of each group will be described with reference to FIG. 4.

[0041] FIG. 4 is a timing chart showing the light emission timing of the light emitting elements.

[0042] In Figure 4, the drive signals for the first group Gr1 to the fourth group Gr4 are shown in order from top to bottom. The light-emitting time Ton indicates the time during which the light-emitting elements 41 of each group are emitting light (ON), and each drive signal is set to be ON for a time corresponding to one pixel and then switched OFF. The line period Th is the line period of the horizontal synchronization signal and corresponds to the time for one line, and is equivalent to the time from when the light-emitting elements 41 are turned ON to when they are switched OFF and then turned ON again. The phase difference ΔT indicates the phase shift of the drive signals between adjacent groups.

[0043] In this embodiment, the first group Gr1, the second group Gr2, the third group Gr3, and the fourth group Gr4 are set to emit light in this order with a time difference. That is, after the first group Gr1 is turned on, the second group Gr2 is turned on when a time corresponding to the phase difference ΔT has elapsed. Thereafter, the third group Gr3 and the fourth group Gr4 are turned on in the same manner as above, successively turning on as the time corresponding to the phase difference ΔT has elapsed. In this way, by providing a time difference (phase difference ΔT) between the timing at which the light emitting elements 41 included in each group start and stop emitting light, it is possible to suppress momentary increases in current fluctuation.

[0044] In the exposure device 12, it is preferable that the product of the phase difference ΔT and the number of groups n (4 in this embodiment) is set to satisfy the relationship "Th>ΔT×n" so that the emission start timing of the light-emitting elements 41 of all groups falls within the time of the line period Th.

[0045] However, when a phase difference ΔT is provided to stagger the light emission timing for each group, there is a problem that steps occur in the exposed image. Next, steps in the image will be described with reference to FIG.

[0046] FIG. 5 is an explanatory diagram showing an example of an image exposed in a reference example.

[0047] In the image forming apparatus 100, vertical and horizontal coordinates are set for each pixel GS of the image to be formed. The horizontal direction X is the width direction of the paper and corresponds to the axial direction (main scanning direction S) of the photosensitive drum 3. The vertical direction Y is the length direction of the paper and corresponds to the rotation direction (sub-scanning direction H) of the photosensitive drum 3.

[0048] For ease of explanation, below, a coordinate in the horizontal direction X may be abbreviated as Xn (n is a natural number), and a coordinate in the vertical direction Y may be abbreviated as Ym (m is a natural number). For example, X1 is the coordinate corresponding to the light-emitting element 41 of d1, and X2 is the coordinate corresponding to the light-emitting element 41 of d2. Furthermore, Y1 is the coordinate corresponding to the pixel GS located at the top in the vertical direction Y, and Y2 is the coordinate corresponding to the pixel GS located one pixel below Y1. FIG. 5 shows an extracted portion of an image (first image GZ1) formed according to a reference example, and the coordinate P of each pixel GS may be abbreviated as "P(Xn, Ym)."

[0049] In the reference example, the step pitch L is an integer multiple of the pixel size (D) in the sub-scanning direction H. When the photosensitive drum 3 rotates at a peripheral speed V in the sub-scanning direction H, the product of the line period Th and the peripheral speed V is equal to the pixel size in the sub-scanning direction H, and is set to satisfy the relationship "Th × V = D." In this case, adjacent pixels GS in the horizontal direction X have a phase difference ΔT in their light emission timing. For example, a step α occurs in the vertical direction Y between P(1,1) and P(2,1). Here, the step α is based on the peripheral speed V and the phase difference ΔT and corresponds to the value of "ΔT × V." The step increases with increasing shift in the horizontal direction X. When comparing pixels GS with the largest phase difference ΔT, for example, P(4,1) and P(5,1), the step is "3 × α."

[0050] In contrast to this, in this embodiment, steps are prevented from occurring in the exposed image by appropriately setting the step pitch L. Next, an image in which the occurrence of steps has been eliminated will be described with reference to FIG.

[0051] FIG. 6 is an explanatory diagram showing an example of an image exposed in the first embodiment of the present disclosure.

[0052] 6, like FIG. 5, shows an extracted portion of an image (second image GZ2) formed by this embodiment. In this embodiment, the step pitch L is corrected based on a phase correction value obtained by multiplying the peripheral speed V by the phase difference ΔT. Specifically, the step pitch L is a value obtained by adding the phase correction value to an integer multiple of the pixel size in the sub-scanning direction H. The phase correction value is set to the same value (ΔT × V) as the step difference α generated in the reference example, and the step pitch L is expressed by the formula "L = D + α".

[0053] By correcting the value of the step pitch L based on the phase correction value, the step α is eliminated. As a result, in the second image GZ2, the pixels GS are neatly arranged in a grid pattern. In this way, by dividing the light-emitting elements 41 into groups that emit light, appropriately setting the distance between each group, and controlling the light emission at appropriate timing, it is possible to suppress inrush current, obtain the necessary exposure amount, prevent image stepping, and avoid image quality degradation. Furthermore, by using the size of the pixels GS exposed by the light-emitting elements 41 as a reference and correcting it based on the phase correction value, it is possible to appropriately set the distance between the element rows.

[0054] In this embodiment, the distance between the element rows is set to a distance of about one pixel, but the present invention is not limited to this and the distance may be set to a distance of several pixels. In this case, the step pitch L may be set to satisfy the relationship "L = D × k + α" (k is a natural number).

[0055] Furthermore, the signal output unit 51 may adjust the phase of the drive signal so that the phase correction value remains constant when the circumferential speed of the photosensitive drum 3 changes. By adjusting the phase correction value so that it does not change, it is possible to prevent stepping in the image even when the circumferential speed of the photosensitive drum 3 changes.

[0056] (Second embodiment) Next, an image forming apparatus according to a second embodiment of the present disclosure will be described with reference to the drawings. The second embodiment differs from the first embodiment in the group configuration. Note that the second embodiment has substantially the same configuration as the first embodiment shown in FIGS. 1 to 6, so a description thereof will be omitted and only the differences will be described.

[0057] FIG. 7 is a schematic plan view showing a panel member according to the second embodiment of the present disclosure.

[0058] 7, similar to FIG. 6, a single panel member 12a is illustrated. The second embodiment has the same arrangement of light-emitting elements 41 as the first embodiment, but the grouping is different. Specifically, the light-emitting elements 41 designated by d1 and d5 are grouped in a first group Gr1 on the first line, the light-emitting elements 41 designated by d2 and d6 are grouped in a second group Gr2 on the second line, the light-emitting elements 41 designated by d3 and d7 are grouped in a third group Gr3 on the third line, and the light-emitting elements 41 designated by d4 and d8 are grouped in a fourth group Gr4 on the fourth line. The light-emitting elements 41 designated by d9 and d13 are grouped in a fifth group Gr5 on the first line, the light-emitting elements 41 designated by d10 and d14 are grouped in a sixth group Gr6 on the second line, the light-emitting elements 41 designated by d11 and d15 are grouped in a seventh group Gr7 on the third line, and the light-emitting elements 41 designated by d12 and d16 are grouped in an eighth group Gr8 on the fourth line.

[0059] That is, the light emitting elements included in the element column arranged on the same line are also divided into multiple groups, such as the first group Gr1 and the fifth group Gr5. In this way, by dividing the element groups to be lit not only by stages but also within the element column, the divided lighting groups can be set more precisely, and the inrush current can be further reduced.

[0060] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0061] 3 Photoconductor drum (an example of a photoconductor) 12 Exposure equipment 12a Panel member 41 Light-emitting element 51 Signal output section 52 Drive unit 100 Image forming device S Main scanning direction H Sub-scanning direction

Claims

1. An exposure device including a panel member facing a photosensitive member and having a plurality of light-emitting elements, a signal output unit that outputs drive signals having different phases; a drive unit that causes each of the plurality of light-emitting elements to emit light individually based on the drive signal, When the direction along the rotation axis of the photosensitive member is defined as the main scanning direction and the direction perpendicular to the main scanning direction is defined as the sub-scanning direction, The panel member has element rows in which the plurality of light-emitting elements are arranged in the main scanning direction, and the element rows are arranged in a plurality of stages in the sub-scanning direction, the signal output unit outputs the drive signals with a phase difference to each of the element arrays; The distance between adjacent element rows in the sub-scanning direction is set based on a phase correction value obtained by multiplying the peripheral speed of the photosensitive member surface by the phase difference. An exposure apparatus characterized by:

2. 2. The exposure apparatus according to claim 1, the plurality of light emitting elements in the element row are divided into a plurality of groups, The signal output unit outputs the drive signals with a phase difference to each of the groups. An exposure apparatus characterized by:

3. 2. The exposure apparatus according to claim 1, The signal output unit adjusts the phase of the drive signal so that the phase correction value is kept constant when the peripheral speed of the surface of the photosensitive member changes. An exposure apparatus characterized by:

4. 2. The exposure apparatus according to claim 1, The distance between adjacent element rows in the sub-scanning direction is a value obtained by adding the phase correction value to an integer multiple of a pixel size in the sub-scanning direction. An exposure apparatus characterized by:

5. An image forming apparatus comprising the exposure device according to claim 1.

Images