Exposure device and image formation device

Abstract

To minimize an influence of deflection of a part where light-emitting elements of a substrate are mounted, which is caused by excessive force applied to the substrate.SOLUTION: An exposure device for exposing a photoreceptor with light includes a substrate forming a longitudinal shape stretching in an axial direction of the photoreceptor, a plurality of light-emitting elements which are mounted on one surface of the substrate and are aligned in a longitudinal direction of the substrate, a lens array for condensing light emitted from the light-emitting elements on the photoreceptor, a holding body for holding the substrate and the lens array, and contact points which are provided on a surface opposite to a surface where the light-emitting elements of the substrate are mounted, are electrically connected to the light-emitting elements, and input a signal for controlling light emission of the light-emitting elements through contact terminals that are separably brought into contact therewith, the contact points arranged at positions which do not overlap a region where the light-emitting elements of the substrate are mounted on front and rear surfaces of the substrate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an exposure device that exposes a photoconductor and an image forming apparatus equipped with the exposure device. [Background technology]

[0002] Conventionally, electrophotographic image forming devices have been widely used in which an exposure device equipped with an LED array and a lens array forms an electrostatic latent image on the surface of a photoconductor, and then toner is applied to the electrostatic latent image to develop the toner image (Patent Document 1).

[0003] In a conventional exposure device, a substrate on which an LED array is mounted is attached to a lens holder via an adhesive. An electrical connection between the substrate on which the LED array is mounted and a main body control unit of the image forming apparatus is made using a flexible flat cable (hereinafter also referred to as FFC). A connector is mounted on the substrate on which the LED array is mounted, and the FFC is removably connected to the connector mounted on the substrate, thereby electrically connecting the substrate to the main body control unit of the image forming apparatus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-62853 A Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional exposure devices, the position of the board, the amount of light, etc. are adjusted using a tool before the exposure device is installed in the image forming device. At that time, the position of the board, the amount of light, etc. are adjusted by electrically connecting the board and the tool using an FFC, just like the image forming device.

[0006] However, because the board on which the LED array is mounted is long, the force applied to the board when inserting and removing the FFC could cause the part of the board where the LED array is mounted to bend.In particular, if the connector overlaps the mounting area of ​​the LED array on the front and back of the board, excessive force could be applied to the mounting area of ​​the LED array on the board, causing a greater bending of the part of the board where the LED array is mounted.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to minimize the effect of bending of the portion of the board on which an LED array is mounted, which is caused by excessive force being applied to the board. [Means for solving the problem]

[0008] A typical configuration of the present invention for achieving the above-mentioned object is an exposure device for exposing a photosensitive body, comprising a substrate having a longitudinal shape extending in the axial direction of the photosensitive body, a plurality of light-emitting elements mounted on one side of the substrate and arranged in the longitudinal direction of the substrate, a lens array for focusing light emitted from the light-emitting elements onto the photosensitive body, a holder for holding the substrate and the lens array, and contacts provided on the side of the substrate opposite to the side on which the light-emitting elements are mounted, electrically connected to the light-emitting elements, and for inputting a signal for controlling the light emission of the light-emitting elements through a contact terminal that is in detachable contact with the light-emitting elements, wherein the contacts are positioned on the front and back surfaces of the substrate in positions that do not overlap the areas on the substrate on which the light-emitting elements are mounted. Effect of the Invention

[0009] According to the present invention, it is possible to minimize the influence of bending of the portion of the board on which the light emitting element is mounted, which is caused by application of an excessive force to the board. [Brief description of the drawings]

[0010] [Figure 1] 1A, 1B, and 1C are explanatory diagrams of a substrate according to an embodiment of the present invention. [Diagram 2] Schematic cross-sectional view of an image forming apparatus [Diagram 3]FIG. 1 is a schematic perspective view of an optical print head provided in an image forming apparatus; [Figure 4] (a), (b), and (c) are diagrams showing the substrate, and (d) and (e) are diagrams showing the lens array. [Diagram 5] (a) and (b) Schematic diagram showing warpage of the substrate of the comparative example [Figure 6] (a) and (b) are schematic diagrams showing the warpage of the substrate in the embodiment. [Figure 7] FIG. 2 is an enlarged view of the connector and check pad of the board according to the embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail by way of example with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions, and are not intended to limit the scope of the present invention to those alone.

[0012] (Image forming device) First, a schematic configuration of the image forming apparatus 1 will be described. Fig. 2 is a schematic cross-sectional view of the image forming apparatus 1. The image forming apparatus 1 shown in Fig. 2 is a color printer (MFP: Multi Function Printer) equipped with a reading device, but the embodiment may be a copier that does not have a reading device. Furthermore, the embodiment is not limited to a so-called tandem type color image forming apparatus equipped with multiple photosensitive drums 103 as shown in Fig. 2, but may be a color image forming apparatus equipped with one photosensitive drum 103 or an image forming apparatus that forms a monochrome image.

[0013] The image forming apparatus 1 shown in FIG. 2 includes four image forming units 102Y, 102M, 102C, and 102K (hereinafter, collectively referred to simply as "image forming units 102") that form toner images of yellow, magenta, cyan, and black, respectively.

[0014] The image forming units 102Y, 102M, 102C, and 102K are provided with photosensitive drums 103Y, 103M, 103C, and 103K (hereinafter, also collectively referred to simply as "photosensitive drum 103"). These photosensitive drums are arranged at a distance from each other.

[0015] The image forming units 102Y, 102M, 102C, and 102K are also provided with chargers 104Y, 104M, 104C, and 104K (hereinafter, also collectively referred to simply as "charger 104") that charge the photosensitive drums 103Y, 103M, 103C, and 103K, respectively.

[0016] Further, the image forming units 102Y, 102M, 102C, and 102K are provided with LED (Light Emitting Diode, hereinafter referred to as LED) exposure units 500Y, 500M, 500C, and 500K (hereinafter collectively referred to as "exposure unit 500") as exposure light sources that emit light to expose the photosensitive drums 103Y, 103M, 103C, and 103K. The image forming apparatus 1 shown in FIG. 2 is a so-called "lower surface exposure type" image forming apparatus that exposes the photosensitive drum 103 from below.

[0017] Furthermore, the image forming units 102Y, 102M, 102C, and 102K each include a developing unit 106Y, 106M, 106C, and 106K (hereinafter collectively referred to as "developing unit 106") that develops the electrostatic latent image on the photosensitive drum 103 with toner and develops a toner image of each color on the photosensitive drum 103. The letters Y, M, C, and K attached to the reference characters indicate the colors of the toner.

[0018] The image forming apparatus 1 includes an intermediate transfer belt 107 onto which a toner image formed on a photosensitive drum 103 is transferred, and primary transfer rollers 108 (Y, M, C, K) which sequentially transfer the toner images formed on the photosensitive drum 103 onto the intermediate transfer belt. The image forming apparatus 1 also includes a secondary transfer roller 109 which transfers the toner image on the intermediate transfer belt 107 onto a recording material S conveyed from a paper feed unit 101, and a fixing device 100 which fixes the secondarily transferred image onto the recording material S.

[0019] After the primary transfer, toner remains on the surfaces of the photosensitive drums 103Y, 103M, 103C, and 103K. The remaining toner is removed by drum cleaning devices (first cleaning devices) 8Y, 8M, 8C, and 8K (hereinafter, also collectively referred to as "drum cleaning devices 8") and collected in a collected toner container 5.

[0020] After the secondary transfer, toner remains on the surface of the intermediate transfer belt 107. This residual toner is removed by a belt cleaning device (second cleaning device) 7 and collected in a collected toner container 5.

[0021] (Image formation process) Next, the image forming process of the image forming apparatus will be briefly described. The charger 104Y charges the surface of the photosensitive drum 103Y. The exposure unit 500Y exposes the surface of the photosensitive drum 103Y charged by the charger 104Y. As a result, an electrostatic latent image is formed on the photosensitive drum 103Y. Next, the developer 106Y develops the electrostatic latent image formed on the photosensitive drum 103Y with yellow toner. The yellow toner image developed on the surface of the photosensitive drum 103Y is transferred onto the intermediate transfer belt 107 by the primary transfer roller 108Y. Magenta, cyan, and black toner images are also formed in a similar image forming process and transferred to the intermediate transfer belt 107 so as to be superimposed on each other.

[0022] The toner images of each color transferred onto the intermediate transfer belt 107 are transported to a secondary transfer portion T2 by the intermediate transfer belt 107. A transfer bias is applied to a secondary transfer roller 109 disposed at the secondary transfer portion T2 to transfer the toner images onto a recording material S. The toner images transported to the secondary transfer portion T2 are transferred onto the recording material S transported from a paper feed portion (paper feed cassette) 101 by the transfer bias of the secondary transfer roller 109.

[0023] The recording material S is stored in a stacked form in the paper feed unit 101, and is fed to the conveying path 20 in accordance with the image formation timing. The paper feed method is as follows: first, the leading edge of the recording material S is flipped up by the friction of the paper feed roller 80, and only one sheet of the recording material S is conveyed to the conveying path 20 by a pair of paper separating conveying rollers 9a, 9b for preventing double feeding of the recording material S. Thereafter, the recording material S is pulled out by the pair of conveying rollers 10a, 10b, and conveyed through the conveying path 20 to the pair of registration rollers 11a, 11b, where it is stopped temporarily. Incidentally, the pair of registration rollers 11a, 11b performs skew correction and timing correction, and then conveys the recording material to the secondary transfer unit T2.

[0024] The recording material S onto which the toner image has been transferred at the secondary transfer portion T2 is conveyed to the fixing device 100. The fixing device 100 fixes the toner image onto the recording material S by heat and pressure. The recording material S which has been subjected to the fixing process by the fixing device 100 is discharged to a paper discharge portion 111.

[0025] 2, the image forming apparatus 1 includes toner containers 4Y, 4M, 4C, and 4K (hereinafter, collectively referred to simply as "toner containers 4"). When an image is formed, the amount of toner in the developing device 106 decreases. At that time, the toner is supplied to the developing device 106 from the toner containers 4Y, 4M, 4C, and 4K provided corresponding to the image forming units 102Y, 102M, 102C, and 102K through pipes (not shown).

[0026] (Basic structure of optical print head) Next, the optical print head (exposure head, exposure device) 105 provided in the exposure unit 500 will be described. Here, as an example of an exposure method adopted in an electrophotographic image forming apparatus, there is a laser beam scanning exposure method in which a semiconductor laser irradiation beam is scanned by a rotating polygon mirror or the like and a photosensitive drum is exposed via an f-θ lens or the like. The "optical print head 105" described in this embodiment is used in an LED exposure method in which the photosensitive drum 103 is exposed to light using light emitting elements such as LEDs arranged along the rotation axis direction of the photosensitive drum 103, and is not used in the laser beam scanning exposure method mentioned above.

[0027] The optical print head 105 described in this embodiment is provided vertically below the rotation axis of the photosensitive drum 103, and an LED 503 included in the optical print head 105 exposes the photosensitive drum 103 from below. Fig. 3 is a schematic perspective view of the optical print head 105 provided in the image forming apparatus 1 of this embodiment.

[0028] The optical print head (exposure head) 105 has an elongated shape (longitudinal shape) extending in the direction of the rotation axis of the photosensitive drum 103. The optical print head 105 includes a substrate 502, a light-emitting element mounted on the substrate 502, a lens array 506, and a holder 505 that holds the substrate 502 and the lens array 506. Here, the optical print head 105 includes an LED 503 (Light Emitting Diode) as a light-emitting element that emits light (see FIG. 4(c)). The substrate 502 is installed inside the holder 505. The holder 505 is provided with a lens attachment portion 701 for attaching the lens array 506.

[0029] The holder 505 is a thin metal plate having a thickness of about 1 mm, and is a part processed by pressing an electrolytic galvanized steel sheet.

[0030] The lens attachment portion 701 of the holder 505 is an opening slightly larger than the lens array 506, and the lens array 506 is fixed to the holder 505 with an adhesive 507. The substrate 502 is formed slightly smaller than the holder 505, and the position of the substrate 502 is adjusted so that the optical axis of the LEDs 503 is aligned with the center of the lens array 506. After that, the substrate 502 is fixed to the holder 505 with an adhesive (not shown) between the wall surfaces on both sides of the substrate 502 in the short direction (direction perpendicular to the long direction) of the holder 505. This adhesive is, for example, an ultraviolet-curing adhesive, and is applied to the bonding location in a liquid or gel state and then cured by irradiation with ultraviolet light.

[0031] The substrate 502 held by the holder 505 will now be described. Fig. 4(a) is a schematic perspective view of the substrate 502. Fig. 4(b) shows an arrangement of a plurality of LEDs 503 provided on the substrate 502, on the substrate 502. Fig. 4(c) is an enlarged view of Fig. 4(b).

[0032] An LED chip 639 is mounted on the substrate 502. As shown in Fig. 4(a), the LED chip 639 is provided on one surface of the substrate 502, and a long FFC connector 504 is provided on the other surface (the surface opposite to the side on which the light emitting elements are arranged). The FFC connector 504 is attached to the lower surface of the substrate 502 so that its longitudinal direction is along the longitudinal direction of the substrate 502. The substrate 502 is provided with wiring for supplying signals to each LED chip 639. One end of a flexible flat cable (hereinafter also referred to as FFC) 160, as an example of a cable, is removably connected to the connector 504.

[0033] The main body of the image forming apparatus 1 is provided with a control board (not shown) having a control unit and a connector. The other end of the FFC 160 is connected to the connector of the control board. That is, the FFC 160 electrically connects the control board (control unit) of the main body of the image forming apparatus 1 and the board 502 of the optical print head 105. A control signal (drive signal) is input to the board 502 from the control unit of the main body of the image forming apparatus 1 via the FFC 160 and the connector 504. The LED chip 639 is driven by the control signal input to the board 502.

[0034] The LED chip 639 mounted on the substrate 502 will now be described. As shown in Fig. 4(b) and Fig. 4(c), a plurality of LED chips 639-1 to 639-29 (29 chips) each having a plurality of LEDs 503 (an example of a light-emitting element) arranged thereon are arranged on one surface of the substrate 502. Each of the LED chips 639-1 to 639-29 has 516 LEDs 503 arranged in a row in its longitudinal direction. In the longitudinal direction of the LED chip 639, a center-to-center distance k2 between adjacent LEDs 503 corresponds to the resolution of the image forming apparatus 1.

[0035] The LED chips 639-1 to 639-29 are alternately arranged in two rows along the rotation axis direction of the photosensitive drum 103. That is, as shown in FIG. 4(b), the odd-numbered LED chips 639-1, 639-3, . . . 639-29 counting from the left side are mounted in a row in the longitudinal direction of the substrate 502, and the even-numbered LED chips 639-2, 639-4, . . . 639-28 are mounted in a row in the longitudinal direction of the substrate 502. By arranging the LED chips 639 in this manner, as shown in FIG. 4(c), the center-to-center distance k1 between the LEDs arranged at one end of one LED chip 639 and the other end of the other LED chip 639 in different adjacent LED chips 639 in the longitudinal direction of the LED chips 639 can be made equal to the center-to-center distance k2 between the adjacent LEDs 503 on one LED chip 639.

[0036] In this embodiment, the light-emitting element (exposure light source) is a semiconductor LED, which is a light-emitting diode, but it may be, for example, an OLED (Organic Light Emitting Diode). This OLED is also called organic EL (Organic Electro-Luminescence), and is a current-driven light-emitting element. For example, the OLEDs are arranged in a line along the main scanning direction (the axial direction of the photosensitive drum 2) on a TFT (Thin Film Transistor) substrate, and are electrically connected in parallel by power supply wiring also provided along the main scanning direction.

[0037] Next, the lens array 506, which is a lens assembly, will be described. FIG. 4(d) is a schematic diagram of the lens array 506 when viewed from the photosensitive drum 103 side. FIG. 4(e) is a schematic perspective view of the lens array 506. As shown in FIG. 4(d), the lens array 506 focuses light emitted from the light emitting element onto the photosensitive drum 103. The lens array 506 is a lens assembly having a plurality of lenses. These lenses are arranged in two rows along the arrangement direction of the plurality of LEDs 503. The lenses are arranged alternately such that one lens in one row is arranged so as to be in contact with both of the lenses adjacent to each other in the arrangement direction of the lenses in the other row. Each lens is a cylindrical glass rod lens. The material of the lens is not limited to glass, and may be plastic. The shape of the lens is not limited to cylindrical, and may be a polygonal column such as a hexagonal column.

[0038] The dotted line Z in FIG. 4(e) indicates the optical axis of the lens. The optical print head 105 can be moved in a direction generally along the optical axis of the lens indicated by the dotted line Z (hereinafter also referred to as the optical axis direction) by a moving mechanism (not shown). The optical axis of the lens here means a line connecting the center of the light emission surface of the lens and the focal point of the lens. The lens array 506 is a lens assembly having a plurality of lenses, and the above-mentioned "optical axis" is the optical axis of any of the plurality of lenses. Strictly speaking, the lenses in the lens array 506 may be slightly inclined relative to each other. This is due to the tolerance at the time of assembly. However, the deviation of the tolerance level here is not taken into consideration when defining the direction of the optical axis. Therefore, it is considered that the optical axes of the plurality of lenses are all in the same direction. The lens array 506 has a role of concentrating the light emitted from the LED 503 on the surface of the photosensitive drum 103. That is, the radiated light emitted from the LED 503 is incident on the lens of the lens array 506. The lens has a function of converging the incident radiation onto the surface of the photosensitive drum 103 .

[0039] The attachment position of the lens array 506 relative to the lens attachment portion 701 (see FIG. 3) is adjusted when assembling the optical print head 105. Specifically, the attachment position of the lens array 506 relative to the lens attachment portion 701 (see FIG. 3) is adjusted so that the distance between the light emitting surface of the LED 503 and the light incident surface of the lens and the distance between the light exit surface of the lens and the surface of the photosensitive drum 103 are approximately equal.

[0040] (Board contacts) Next, the configuration of the substrate 502 will be described in more detail with reference to FIGS. 1(a), 1(b), 1(c), 5, 6, and 7. FIG.

[0041] Fig. 1(a) is a view of the substrate 502 seen from the connector 504 side. Fig. 1(b) is a view of the substrate 502 seen from the LED chip 639 side. Fig. 1(c) is a view of the substrate 502 seen from the thickness direction. Fig. 7 is an enlarged view of the connector 504 and check pad 601 of the substrate 502.

[0042] The substrate 502 has a longitudinal shape extending in the axial direction of the photosensitive drum 103, as shown in FIGS.

[0043] 1(a), the substrate 502 includes an IC 600 that controls the light emission of the LED chip 639. The IC 600 is mounted on the surface of the substrate 502 opposite to the surface on which the LED chip 639 is mounted. The IC 600 is electrically connected to the LED chip 639.

[0044] As described above, wiring (not shown) for supplying signals to the LED chips 639 is provided on the substrate 502. Among the wirings of the substrate 502, a plurality of wirings (not shown) for supplying control signals for controlling the light emission of each LED chip 639 is connected to the IC 600. The plurality of wirings connected to the IC 600 are connected to each LED chip 639. In this manner, the IC 600 is electrically connected to the LED chips 639 by the wirings of the substrate 502.

[0045] 1(a) and 1(c), the substrate 502 includes an FFC connector 504 to which the FFC 160 is removably connected. The FFC connector 504 is mounted on the surface of the substrate 502 opposite to the surface on which the LED chip 639 is mounted. The FFC connector 504 is electrically connected to the LED chip 639.

[0046] Among the wirings of the above-mentioned substrate 502, a wiring (not shown) for supplying a control signal for controlling light emission of the LED chip 639 is connected to the FFC connector 504. The wiring for supplying the control signal, which is connected to the FFC connector 504, is connected to the IC 600. That is, the FFC connector 504 is electrically connected to the LED chip 639 via the IC 600.

[0047] Among the wirings of the above-mentioned substrate 502, wirings (not shown) for supplying power to control the light emission of the LED chips 639 are connected to the FFC connector 504. The wirings for supplying power connected to the FFC connector 504 are connected in parallel to the LED chips 639. The wirings for supplying power connected to the FFC connector 504 are connected directly to the LED chips 639 without going through the IC 600.

[0048] 1(a), the substrate 502 further includes a check pad 601 as a contact point in addition to the FFC connector 504. A plurality of check pads 601 are provided. The check pads 601 are provided on the surface of the substrate 502 opposite to the surface on which the LED chip 639 is mounted. The check pad 601 is a copper foil portion provided on the substrate 502, and is a contact point with which a contact probe (not shown) as a contact terminal connected to an adjustment tool described later can be detachably contacted. A signal for controlling light emission of the LED chip 639 is input to the check pad 601 through the contact probe (not shown) as a contact terminal detachably contacted.

[0049] 7, the multiple check pads 601 are electrically connected to the LED chip 639. As shown in FIG. 7, the multiple check pads 601 are each electrically connected to the FFC connector 504 by wiring 603 provided on the substrate 502. The multiple wiring 603 connecting the check pads 601 and the FFC connector 504 includes wiring for supplying a control signal that controls the light emission of the LED chip 639, and wiring for supplying a power source that controls the light emission of the LED chip 639.

[0050] In other words, the multiple check pads 601 include contacts connected to wiring that is connected to the FFC connector 504 and that supplies a control signal for controlling light emission of the LED chip 639. The multiple check pads 601 also include contacts connected to wiring that is connected to the FFC connector 504 and that supplies a power source for controlling light emission of the LED chip 639.

[0051] As described above, the FFC connector 504 is electrically connected to the IC 600 by wiring that supplies a control signal, and is electrically connected to the LED chip 639 by wiring that supplies power. The IC 600 is further electrically connected to the LED chip 639 by wiring that supplies a control signal. In this way, the check pad 601 is electrically connected to the LED chip via the FFC connector 504 by wiring provided on the substrate 502.

[0052] As shown in FIGS. 1( b ) and 1 ( c ), the substrate 502 includes a plurality of LED chips 639 in which a plurality of LEDs 503 are arranged, and the LED chips 639 are mounted on one surface of the substrate 502 .

[0053] As shown in FIG. 1(a), the check pad 601 is disposed at one end of the substrate 502 in the longitudinal direction.

[0054] 1(b), the check pad 601 is disposed at a position on the front and back surfaces of the substrate 502 that does not overlap the area where the LED chip 639 of the substrate 502 is mounted. In other words, the check pad 601 is disposed outside the area where the LED chip 639 of the substrate 502 is mounted in the longitudinal direction of the substrate 502.

[0055] At this time, the check pad 601 is arranged in a position in the longitudinal direction of the substrate 502 such that the distance L1 between the check pad 601 and the end of the substrate 502 on which the check pad 601 is provided is narrower than the distance L3 between the check pad 601 and the area on the substrate 502 on which the LED chip 639 is mounted (L3>L1).

[0056] 1(a), the FFC connector 504 is disposed offset toward one end from the center in the longitudinal direction of the substrate 502. The check pad 601 is disposed closer to the end than the FFC connector 504 in the longitudinal direction of the substrate 502.

[0057] Specifically, the check pad 601 is arranged in a position in the longitudinal direction of the board 502 such that the distance L1 between the check pad 601 and the end of the board 502 on which the check pad 601 is provided is narrower than the distance L2 between the check pad 601 and the FFC connector 504 (L2>L1).

[0058] In addition, since the board 502 shown in FIG. 1(a) is configured such that the FFC connector 504 is positioned closer to the end of the board 502 in the longitudinal direction than the IC 600, it can also be said that the check pad 601 is positioned closer to the end of the board 502 in the longitudinal direction than the IC 600.

[0059] (Adjusting the position of the board and the amount of light) Before assembling the optical print head 105 to the image forming apparatus 1, the substrate 502 is electrically connected to a tool (not shown) to adjust the position of the substrate 502, the amount of light, etc. The check pad 601 provided on the substrate 502 is used when adjusting the position of the substrate 502, the amount of light, etc.

[0060] As described above, in the substrate 502 according to this embodiment, the check pad 601 is disposed at one end in the longitudinal direction of the substrate 502. Also, the check pad 601 is disposed at a position on the front and back surfaces of the substrate 502 that does not overlap the region on which the LED chip 639 of the substrate 502 is mounted.

[0061] Here, the present embodiment will be described using a comparative example. Figures 5(a) and 5(b) are diagrams showing a substrate of the comparative example. Figures 6(a) and 6(b) are diagrams showing a substrate of the present embodiment.

[0062] 5(a) and 5(b), the check pad 601 is disposed at approximately the center in the longitudinal direction of the substrate 502. The check pad 601 is also disposed at a position on the front and back surfaces of the substrate 502 that overlaps with an area on the substrate 502 where an LED chip 639 is mounted.

[0063] During the above-mentioned adjustment, first, multiple points in the longitudinal direction of the substrate 502 are sucked by suction pads 602 to correct any warping or bending of the substrate 502 that occurs during assembly of the optical print head 105. Then, a contact probe (not shown) electrically connected to a tool is brought into contact with a check pad 601 provided on the substrate 502. Then, a signal for controlling the emission of light from the LED chip is input to the substrate 502 through the contact probe, and the position of the substrate 502 is adjusted while the LED chip 639 of the substrate 502 is being emitted. Then, once the position has been determined, the substrate 502 is adhesively fixed to the holder 505.

[0064] Although not shown, for example, contact probes are used in which the same number of probes as the number of check pads 601 are fixed to a support member in accordance with the positions of check pads 601. Each probe has a contact rod (plunger) that contacts the check pad supported slidably in a hollow cylindrical member (barrel, pipe), and is biased in the moving direction by a biasing member (spring) provided inside the cylindrical member. With this configuration, even if substrate 502 is moved for position adjustment, the contact rod of the probe strokes following the movement of substrate 502, so that the probe and check pad 601 do not separate and the contact state is maintained.

[0065] In order to maintain this contact state, a pressing force F of the probe acts on the substrate 502. In the comparative example, as shown in FIG. 5(a), the check pad 601 is disposed in the center of the substrate 502 in the longitudinal direction. Therefore, the pressing force F of the probe occurs in the center of the substrate 502 in the longitudinal direction where the check pad 601 is disposed, and the substrate 502 is affected by the pressing force of the probe over the entire longitudinal area. In contrast, in this embodiment, as shown in FIG. 6(a), the check pad 601 is disposed at one end of the substrate 502 in the longitudinal direction. Therefore, the pressing force F of the probe occurs at the end of the substrate 502 in the longitudinal direction where the check pad 601 is disposed, and the substrate 502 is less affected by the pressing force of the probe than in the comparative example. As a result, according to this embodiment, the effect of bending of the portion of the substrate 502 on which the LED chip 639 is mounted, which is caused by the pressing force F being applied to the substrate 502, can be suppressed.

[0066] Furthermore, in the comparative example, the check pad 601 is disposed within the mounting area of ​​the LED chip 639 of the substrate 502, whereas in this embodiment, the check pad 601 is disposed outside the mounting area of ​​the LED chip 639 of the substrate 502. Therefore, it is possible to minimize the influence of bending of the portion of the substrate 502 on which the LED chip 639 is mounted, which is caused by the application of the pressing force F to the substrate 502.

[0067] During the above-mentioned adjustment, it is also possible to use the FFC 160 instead of the check pad 601. However, when the FFC 160 is used during the adjustment, the FFC 160 needs to be inserted into the FFC connector 504 and removed from the FFC connector 504. Since the board 502 on which the LED chip 639 is mounted is long, the force applied to the board 502 when inserting and removing the FFC 160 may cause bending in the portion of the board 502 on which the LED chip 639 is mounted. In particular, if the FFC connector 504 overlaps the mounting area of ​​the LED chip 639 on the front and back sides of the board 502, excessive force may be applied to the mounting area of ​​the LED chip 639 on the board 502, and a larger bending may occur in the portion of the board on which the LED array is mounted.

[0068] The board 502 according to this embodiment is provided with a check pad 601 in addition to the FFC connector 504. The pressing force of the contact probe (not shown) acting on the board 502 is within a range that maintains a contact state when adjusting the position of the board, and is therefore much smaller than the force of inserting and removing the FFC 160 from the FFC connector 504, which has the force to hold the FFC 160. That is, the pressing force of the contact probe (not shown) acting on the board 502 is much smaller than the force applied to the board 502 when the FFC connector 504 is inserted and removed. Moreover, in the configuration in which the contact probe (not shown) is separated from the check pad 601 as in this embodiment, no force is applied to the board 502 when the FFC 160 is pulled out. Therefore, it is possible to minimize the effect of bending of the part of the board on which the LED chip is mounted, which is caused by excessive force being applied to the board.

[0069] In the above embodiment, the check pad 601 is disposed at one end of the substrate 502 in the longitudinal direction, but the present invention is not limited to this. The check pad 601 may be disposed at both ends of the substrate in the longitudinal direction.

[0070] In the above-described embodiment, the configuration is exemplified as including the FFC connector 504 to which the cable is removably connected, but the present invention is not limited to this. For example, the above-described check pad 601 may be provided as a substitute for the connector 504. In this case, the check pad 601 may be arranged at a position that does not overlap the mounting area of ​​the LED chip 639 on the substrate 502.

[0071] In the above-described embodiment, the check pad is electrically connected to the light-emitting element via a connector, but the present invention is not limited to this. The check pad may have another configuration as long as it is electrically connected to the light-emitting element. [Explanation of symbols]

[0072] 1. Image forming device 102 ... Image forming section 103 ... Photosensitive drum (photoconductor) 105 ... Optical print head (exposure head, exposure device) 160...FFC (flexible flat cable) 500 ... exposure unit 502 ... Substrate 503 ... LED (light emitting element) 504...FFC connector 505...Holding body 506 ... Lens array 600...IC 601 ... Check pad (contact point) 602 ... Suction pad 603 ... Wiring 639 ... LED chip

Claims

1. An exposure device for exposing a photoconductor, comprising: A substrate having a longitudinal shape extending in the axial direction of the photoreceptor; A plurality of light emitting elements mounted on one surface of the substrate and arranged in a longitudinal direction of the substrate; a lens array that focuses the light emitted from the light-emitting element onto a photoconductor; a holder for holding the substrate and the lens array; a contact provided on a surface of the substrate opposite to a surface on which the light emitting element is mounted, electrically connected to the light emitting element, and for inputting a signal for controlling light emission of the light emitting element through a contact terminal that is in detachable contact with the light emitting element; The exposure apparatus according to claim 1, wherein the contacts are arranged on the front and back surfaces of the substrate at positions that do not overlap with regions of the substrate on which the light emitting elements are mounted.

2. a connector mounted on a surface of the board opposite to a surface on which the light emitting element is mounted, electrically connected to the light emitting element, and to which a cable is removably connected; 2. The exposure apparatus according to claim 1, wherein the contacts are arranged closer to an end of the substrate than the connector is in the longitudinal direction of the substrate.

3. 3. The exposure apparatus according to claim 2, wherein the connector is disposed offset toward one end of the substrate from the center in the longitudinal direction of the substrate.

4. 3. The exposure apparatus according to claim 2, wherein the contacts are arranged at positions in the longitudinal direction of the board such that the distance between the contacts and the end of the board on which the contacts are provided is shorter than the distance between the contacts and the connector.

5. 3. The exposure apparatus according to claim 2, wherein the contacts are electrically connected to the light emitting element via the connector.

6. the substrate has wiring for supplying signals to the light-emitting elements, 6. The exposure apparatus according to claim 5, wherein the contacts include contacts connected to wiring that is connected to the connector and that supplies a control signal that controls light emission of the light-emitting element.

7. the substrate has wiring for supplying signals to the light-emitting elements, 6. The exposure apparatus according to claim 5, wherein the contacts include contacts connected to wiring that is connected to the connector and that supplies power to control light emission of the light-emitting element.

8. an IC mounted on a surface of the substrate opposite to a surface on which the light emitting element is mounted, electrically connected to the light emitting element, and controlling light emission of the light emitting element; 3. The exposure apparatus according to claim 2, wherein the contacts are arranged closer to an end of the substrate than the IC is in the longitudinal direction of the substrate.

9. the connector is electrically connected to the light emitting element via the IC, 9. The exposure apparatus according to claim 8, wherein the contacts are electrically connected to the light emitting element via the connector.

10. 2. The exposure apparatus according to claim 1, wherein the contact is disposed at one end in a longitudinal direction of the substrate.

11. An exposure device for exposing a photoconductor, comprising: A substrate having a longitudinal shape extending in the axial direction of the photoreceptor; A plurality of light emitting elements mounted on one surface of the substrate and arranged in a longitudinal direction of the substrate; a lens array that focuses the light emitted from the light-emitting element onto a photoconductor; a holder for holding the substrate and the lens array; a connector mounted on a surface of the board opposite to a surface on which the light emitting element is mounted, electrically connected to the light emitting element, and configured to hold a cable in a removable manner; a contact provided on a surface of the board opposite to the surface on which the light emitting element is mounted, separate from the connector, electrically connected to the light emitting element, and for inputting a signal for controlling light emission of the light emitting element through a contact terminal that is in detachable contact with the light emitting element; The exposure apparatus according to claim 1, wherein the contacts are arranged on the front and back surfaces of the substrate at positions that do not overlap with regions of the substrate on which the light emitting elements are mounted.

12. An image forming apparatus comprising: a photoconductor; and an exposure device according to claim 1 .

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