Image formation apparatus comprising optical print head

Abstract

To provide an image formation apparatus that comprises an optical print head movable vertically between an exposure position for exposing a photosensitive drum and a retracted position for being retracted from the exposure position, and that needs positioning the print head at a predetermined position when the optical print head is located at the exposure position.SOLUTION: An image formation apparatus comprises: a first pressing member configured to press an optical print head in a predetermined direction, the optical print head vertically movable between an exposure position and a retracted position; a second pressing member configured to press the optical print head in the predetermined direction; and a regulating portion that regulates movement of the optical print head in the predetermined direction.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus having an optical print head. [Background technology]

[0002] Some image forming devices such as printers and copiers use an optical print head equipped with a plurality of light emitting elements for exposing a photosensitive drum. Some optical print heads use LEDs (Light Emitting Diodes) or organic EL (Electro Luminescence) as examples of the light emitting elements. The light emitting elements are provided on the surface of a long substrate and are held together with the lens array by a resin or metal holder.

[0003] Patent Document 1 discloses an image forming apparatus having a plurality of organic EL light-emitting elements and an optical print head that can move up and down between an exposure position where a photosensitive drum is exposed and a retracted position away from the exposure position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-213541 A Summary of the Invention [Problem to be solved by the invention]

[0005] In an optical print head that can be moved between a retracted position and an exposure position as described in Patent Document 1, the optical print head at the exposure position needs to be set at a predetermined position. If the optical print head at the exposure position is not set at a predetermined position, there is a risk of misalignment of the image formation position.

[0006] In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of defining the position of an optical print head relative to a photosensitive drum. [Means for solving the problem]

[0007] The image forming apparatus of the present invention is an optical print head having a rotating photosensitive member, a substrate on which a plurality of light-emitting elements that emit light to expose the photosensitive member are arranged along the rotational axis direction of the photosensitive member, and a holding member that holds the substrate, and is characterized in that it is equipped with an optical print head that is movable between an exposure position at which the photosensitive member is exposed and a retracted position retracted from the exposure position, a first pressing member that presses the optical print head in a predetermined direction, a second pressing member that presses the optical print head in the predetermined direction, and a regulating unit that regulates movement of the optical print head in the predetermined direction. Effect of the Invention

[0008] According to the present invention, it is possible to provide an image forming apparatus capable of defining the position of an optical print head with respect to a photosensitive drum. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Diagram 2] FIG. 2 is a diagram for explaining the structure around a drum unit and a developing unit in the image forming apparatus. [Diagram 3] FIG. [Figure 4] 3A and 3B are diagrams for explaining the configuration of a substrate and a lens array. [Diagram 5] 3A and 3B are diagrams for explaining the positional relationship between a substrate and a lens array, and between the lens array and a photosensitive drum. [Figure 6] 5A and 5B are diagrams for explaining how an optical print head moves between an exposure position and a retracted position. [Figure 7] FIG. 4 is a diagram for explaining a link mechanism which is an example of a moving mechanism. [Figure 8] 5A and 5B are diagrams for explaining a mechanism by which a first link member and a second link portion rotate. [Figure 9]13A and 13B are diagrams illustrating a cam mechanism which is another example of a moving mechanism. [Figure 10] FIG. 4 is a diagram for explaining a cleaning mechanism. [Figure 11] FIG. 4 is a diagram for explaining a grounding mechanism. [Figure 12] FIG. 13 is a diagram for explaining a leaf spring that grounds a holding member via a pin. [Figure 13] 5A and 5B are diagrams for explaining a leaf spring that presses the optical print head. [Figure 14] 5A and 5B are diagrams for explaining a pressing position of a leaf spring that presses a pin. [Figure 15] 5A and 5B are diagrams for explaining a pressing position of a leaf spring that presses a pin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. Note that the dimensions, materials, shapes, relative positions, and the like of the components described below are not intended to limit the scope of the present invention unless otherwise specified.

[0011] (Image forming device) First, a schematic configuration of the image forming apparatus 1 will be described. Fig. 1(a) is a schematic cross-sectional view of the image forming apparatus 1. The image forming apparatus 1 shown in Fig. 1(a) is a color printer (SFP: Single Function Printer) that does not include a reading device, but the embodiment may be a copier that includes a reading device. Furthermore, the embodiment is not limited to a color image forming apparatus that includes multiple photosensitive drums 103 as shown in Fig. 1(a), and may be a color image forming apparatus that includes one photosensitive drum 103 or an image forming apparatus that forms a monochrome image.

[0012] The image forming apparatus 1 shown in FIG. 1(a) includes four image forming units 102Y, 102M, 102C, and 102K (hereinafter collectively referred to as "image forming units 102") that form toner images of yellow, magenta, cyan, and black, respectively. The image forming units 102Y, 102M, 102C, and 102K include photosensitive drums 103Y, 103M, 103C, and 103K (hereinafter collectively referred to as "photosensitive drum 103" or photosensitive body), respectively. The image forming units 102Y, 102M, 102C, and 102K include chargers 104Y, 104M, 104C, and 104K (hereinafter collectively referred to as "charger 104") that charge the photosensitive drums 103Y, 103M, 103C, and 103K, respectively. The image forming units 102Y, 102M, 102C, and 102K are provided with LED (Light Emitting Diode, hereinafter referred to as LED) exposure units 520Y, 520M, 520C, and 520K (hereinafter collectively referred to as "exposure units 520") as exposure light sources that emit light to expose the photosensitive drums 103Y, 103M, 103C, and 103K. The image forming units 102Y, 102M, 102C, and 102K are provided with developers 106Y, 106M, 106C, and 106K (hereinafter collectively referred to as "developers 106") as developing means that develop the electrostatic latent image on the photosensitive drum 103 with toner and develop toner images 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.

[0013] The image forming apparatus 1 shown in Fig. 1(a) is an image forming apparatus that employs a so-called "bottom exposure method" in which the photosensitive drum 103 is exposed from below. The following description will be given on the premise that the image forming apparatus employs the bottom exposure method, but an embodiment may also be an image forming apparatus that employs an "top exposure method" in which the photosensitive drum 103 is exposed from above, such as the image forming apparatus 2 shown in Fig. 1(b). In Fig. 1(b), the same reference numerals are used to indicate the same configuration as in Fig. 1(a).

[0014] 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 as a transfer means which transfers the toner image on the intermediate transfer belt 107 onto a recording paper P conveyed from a paper feed unit 101, and a fixing device 100 which fixes the secondarily transferred image onto the recording paper P.

[0015] (Image formation process) The exposure unit 520Y 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. The magenta, cyan, and black toner images are also transferred to the intermediate transfer belt 107 in a similar image formation process.

[0016] The toner images of each color transferred onto the intermediate transfer belt 107 are transported to a secondary transfer section T2 by the intermediate transfer belt 107. A transfer bias is applied to a secondary transfer roller 109 disposed at the secondary transfer section T2 to transfer the toner image onto the recording paper P. The toner image transported to the secondary transfer section T2 is transferred onto the recording paper P transported from the paper feed section 101 by the transfer bias of the secondary transfer roller 109. The recording paper P onto which the toner image has been transferred is transported to a fixing device 100. The fixing device 100 fixes the toner image onto the recording paper P by heat and pressure. The recording paper P that has been fixed by the fixing device 100 is discharged to a paper discharge section 111.

[0017] (Drum unit and developing unit) Drum units 518Y, 518M, 518C, and 518K (hereinafter collectively referred to as "drum unit 518") each having a photosensitive drum 103 are attached to the image forming apparatus 1. The drum unit 518 is a cartridge that is replaced by an operator such as a user or a maintenance technician. The drum unit 518 rotatably supports the photosensitive drum 103. Here, the drum unit 518 also functions as a drum support member that rotatably supports the photosensitive drum 103. That is, the drum unit 518 corresponds to a rotation support member. In this embodiment, the drum support member is also referred to as the drum unit 518. Specifically, the photosensitive drum 103 is rotatably supported by a frame of the drum unit 518. The drum unit 518 may not include the charger 104 or the cleaning device.

[0018] In addition, the image forming apparatus 1 of this embodiment is provided with developing units 641Y, 641M, 641C, and 641K (hereinafter, collectively referred to simply as "developing units 641") that are separate from the drum unit 518. The developing unit 641 of this embodiment is a cartridge in which the developing device 106 shown in FIG. 1(a) and a toner storage unit are integrated. The developing device 106 includes a developing sleeve (not shown) that carries a developer. The developing unit 641 is provided with a plurality of gears for rotating a screw that stirs the toner and carrier. When these gears deteriorate over time, an operator removes the developing unit 641 from the main body of the image forming apparatus 1 and replaces it. The embodiment of the drum unit 518 and the developing unit 641 may be a process cartridge in which the drum unit 518 and the developing unit 641 are integrated.

[0019] Fig. 2(a) is a perspective view showing a schematic structure around drum unit 518 (Y, M, C, K) and developing unit 641 (Y, M, C, K) provided in image forming apparatus 1. Fig. 2(b) is a view showing a state in which drum unit 518 is inserted into image forming apparatus 1 from the outside of the apparatus main body.

[0020] As shown in FIG. 2(a), the image forming apparatus 1 includes a front plate 642 made of sheet metal and a rear plate 643 made of sheet metal. The front plate 642 is a side wall provided on the front side of the image forming apparatus 1. The front plate 642 forms a part of the housing of the apparatus body on the front side of the image forming apparatus 1 body. The rear plate 643 is a side wall provided on the rear side of the image forming apparatus 1. The rear plate 643 forms a part of the housing of the apparatus body on the back side of the image forming apparatus 1 body. As shown in FIG. 2(a), the front plate 642 and the rear plate 643 are disposed facing each other, and a metal beam (not shown) is provided between them. The front plate 642, the rear plate 643, and the beam (not shown) each form a part of the frame of the image forming apparatus 1. Here, with respect to the image forming apparatus 1 or its components in this embodiment, the front side or the front side is the side where the drum unit 518 is inserted and removed (inserted and removed) from the apparatus body.

[0021] An opening is formed in the front side plate 642 so that the drum unit 518 and the developing unit 641 can be inserted and removed from the front side of the image forming apparatus 1. The drum unit 518 and the developing unit 641 are attached to a predetermined position of the image forming apparatus 1 main body through the opening (attached position). The image forming apparatus 1 also includes covers 558Y, 558M, 558C, and 558K (hereinafter collectively referred to as "cover 558") that cover the front side of both the drum unit 518 and the developing unit 641 attached to the attached position. One end of the cover 558 is fixed to the image forming apparatus 1 main body by a hinge, and the cover 558 is rotatable relative to the image forming apparatus 1 main body by the hinge. The replacement work is completed when an operator opens the cover 558, removes the drum unit 518 or the developing unit 641 from the main body, inserts a new drum unit 518 or the developing unit 641, and closes the cover 558.

[0022] Here, as shown in FIG. 2(a) and FIG. 2(b), in the following description, the front plate 642 side with respect to the device main body is defined as the front side (near side or front side), and the rear plate 643 side is defined as the rear side (rear side or back side). In addition, when the photosensitive drum 103K on which the electrostatic latent image of the black toner image is formed is taken as a reference, the side on which the photosensitive drum 103Y on which the electrostatic latent image of the yellow toner image is formed is disposed is defined as the right side. When the photosensitive drum 103Y on which the electrostatic latent image of the yellow toner image is formed is taken as a reference, the side on which the photosensitive drum 103K on which the electrostatic latent image of the black toner image is formed is defined as the left side. Furthermore, the direction perpendicular to the front-rear direction and the left-right direction defined here and vertically upward is defined as the up direction, and the direction perpendicular to the front-rear direction and the left-right direction defined here and vertically downward is defined as the down direction. The defined front direction, rear direction, right direction, left direction, up direction, and down direction are shown in FIG. 2. Moreover, the rotation axis direction of the photosensitive drum 103 described below is a direction that coincides with the front-rear direction shown in Fig. 2. Moreover, the longitudinal direction of the optical print head 105 also coincides with the front-rear direction shown in Fig. 2. In other words, the rotation axis direction of the photosensitive drum 103 and the longitudinal direction of the optical print head 105 coincide with each other.

[0023] (Exposure unit) Next, an exposure unit 520 including the optical print head 105 will be described. The optical print head 105 has a longitudinal shape extending in the direction of the rotation axis of the photosensitive drum 103. The optical print head 105 also includes a holding member 505, a lens array 506, and a substrate (not shown). The lens array 506 and the substrate (not shown) are held by the holding member 505. The holding member 505 is a metal member formed by bending a plate material, such as a zinc-plated steel plate or a cold-rolled steel plate, that has been plated. The holding member 505 is a magnetic material that is magnetized when placed in a magnetic field. 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.

[0024] The exposure unit 520 described in this embodiment is provided vertically below the rotation axis of the photosensitive drum 103. LEDs are provided as light-emitting elements on a substrate (not shown) of the holding member 505, and these light-emitting elements expose the photosensitive drum 103 from below. However, the exposure unit 520 may be provided vertically above the rotation axis of the photosensitive drum 103 and expose the photosensitive drum 103 from above (see FIG. 1(b)). FIG. 3 is a schematic perspective view of the exposure unit 520 provided in the image forming apparatus 1 of this embodiment.

[0025] 3, the exposure unit 520 includes the optical print head 105, a support member 526 (an example of a support frame), a first link mechanism 530, and a second link mechanism 540.

[0026] As shown in FIG. 3, a holding member 505 of the optical print head 105 is provided with an abutment pin 514 (first abutment pin) and an abutment pin 515. Both the abutment pin 514 and the abutment pin 515 are examples of metal pins. For example, the abutment pin 515 is provided on the holding member 505 on one side (the rear side) of the lens array 506 in the direction of the rotation axis of the photosensitive drum 103, and protrudes from both sides of the holding member 505 in the direction of the optical axis of the lens array 506. The abutment pin 514 is similar. When the abutment pin 514 and the abutment pin 515 abut against the drum unit 518, a gap is formed between the light exit surface of the lens array 506 and the photosensitive drum 103. In this way, the optical print head 105 is in contact with the photosensitive drum 103 in the emission direction of the light emitted from the light exit surface. The position of the contact head 105 is determined. In this embodiment, the contact pins 514 and 515 are both straight pins made of metal. In addition, the contact pins 514 and 515 are fixed to the metal holding member 505 by welding. Therefore, it can be said that the contact pins 514 and 515 are electrically connected to the holding member 505. In this manner, in this embodiment, the contact pins 514 and 515 are integrated with the holding member 505. The fixing of the contact pins 514 and 515 to the holding member 505 is not limited to welding, and may be fixed by an adhesive. In addition, the contact pins 514 and 515 may be threaded and fastened to the holding member 505 by being screwed into the holding member 505.

[0027] The first link mechanism 530 includes a link member 535 and a link member 536. The second link mechanism 540 includes a link member 537 and a link member 538. Although details will be described later, the link member 535 is attached to the rear side of the center of the holding member 505 in the direction of the rotation axis of the photosensitive drum 103, and the link member 537 is attached to the front side of the center of the holding member 505 in the direction of the rotation axis of the photosensitive drum 103.

[0028] A slide member 525, which will be described later, slides forward and backward in response to the opening and closing of a cover 558 provided on the front side of the image forming apparatus 1. Link members 535-538 rotate in conjunction with the sliding movement of slide member 525, and optical print head 105 moves up and down.

[0029] In this embodiment, the optical print head 105 is provided vertically below the photosensitive drum 103. That is, in the image forming apparatus 1 in this embodiment, the optical print head 105 exposes the photosensitive drum 103 from vertically below.

[0030] As shown in FIG. 3, the exposure unit 520 includes a support member 526. The support member 526 supports the optical print head 105 via a first link mechanism 530 and a second link mechanism 540. Specifically, a link member 535 of the first link mechanism 530 supports the holding member 505, and a link member 537 of the second link mechanism 540 supports the holding member 505. The part of the link member 535 that supports the holding member 505 is a first support part made of resin. The part of the link member 537 that supports the holding member 505 is a second support part made of resin. The first support part and the second support part directly or indirectly support the holding member 505. As will be described in detail later, since the first support part and the second support part are made of resin, the holding member 505 is not grounded, that is, is in an electrically floating state.

[0031] The support member 526 is formed by bending a metal plate into a U-shape. The support member 526 is a longitudinal member extending in the direction of the rotation axis of the photosensitive drum 103. One end side (near side) of the support member 526 in the longitudinal direction of the support member 526 is fixed to the front side plate 642, and the other end side (far side) of the support member 526 in the longitudinal direction of the support member 526 is fixed to the rear side plate 643. In this way, the position of the support member 526 is fixed with respect to the photosensitive drum 103 on the opposite side to the side where the photosensitive drum 103 is disposed with respect to the holding member 505 in the optical axis direction of the lens array 506. The support member 526 is grounded via one or both of the front side plate 642 and the rear side plate 643.

[0032] The support member 526 includes a slide member 525 that is movable in the longitudinal direction of the support member 526. As the slide member 525 moves relative to the support member 526, the link members 535-538 rotate and the optical print head 105 moves relative to the support member 526.

[0033] Further, an insertion portion 550 into which a cleaning member 600, which will be described later, is inserted is fixed to the support member 526. Since the support member 526 is fixed to the main body of the image forming apparatus 1, the insertion portion 550 is also fixed to the main body of the image forming apparatus 1.

[0034] Next, the substrate 502 and the lens array 506 held by the holding member 505 of the optical print head 105 will be described with reference to Fig. 4. First, the substrate 502 will be described. Fig. 4(a) is a schematic perspective view of the substrate 502. Fig. 4(b1) shows an arrangement of a plurality of LEDs 503 provided on the substrate 502, and Fig. 4(b2) shows an enlarged view of Fig. 4(b1).

[0035] 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 connector 504 is provided on the back surface side. The substrate 502 is provided with wiring for supplying signals to each LED chip 639. One end of a flexible flat cable (FFC) (not shown) is connected to the connector 504. A substrate is provided in the main body of the image forming apparatus 1. The substrate 502 includes a control unit and a connector. The other end of the FFC is connected to the connector. A control signal is input to the substrate 502 from the control unit of the main body of the image forming apparatus 1 via the FFC and the connector 504. The LED chip 639 is driven by the control signal input to the substrate 502.

[0036] The LED chip 639 mounted on the substrate 502 will be described in more detail. As shown in FIG. 4(b1) and FIG. 4(b2), a plurality of LED chips 639-1 to 639-29 (29 chips) on which a plurality of LEDs 503 are arranged are arranged on one surface of the substrate 502. Each of the LED chips 639-1 to 639-29 has 516 LEDs (light-emitting elements) arranged in a row in its longitudinal direction. The center-to-center distance k2 between adjacent LEDs in the longitudinal direction of the LED chip 639 corresponds to the resolution of the image forming apparatus 1. Since the resolution of the image forming apparatus 1 of this embodiment is 1200 dpi, the LEDs are arranged in a row in the longitudinal direction of the LED chips 639-1 to 639-29 such that the center-to-center distance between adjacent LEDs is 21.16 μm. Therefore, the exposure range of the optical print head 105 of this embodiment is about 316 mm. The photosensitive layer of the photosensitive drum 103 is formed with a width of 316 mm or more. Since the length of the long side of A4 size recording paper and the length of the short side of A3 size recording paper are 297 mm, the optical print head 105 of this embodiment has an exposure range capable of forming images on A4 size recording paper and A3 size recording paper.

[0037] 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(b1), 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(b2), 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 on one LED chip 639.

[0038] In this embodiment, the light-emitting element is a semiconductor LED, which is a light-emitting diode, but 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. The OLEDs are arranged in a line along the main scanning direction (the direction of the rotation axis of the photosensitive drum 103) on a TFT (Thin Film Transistor) substrate, for example, and are electrically connected in parallel by power supply wiring also provided along the main scanning direction. In other words, the light-emitting element corresponds to a light-emitting unit.

[0039] Next, the lens array 506 will be described. FIG. 4(c1) is a schematic diagram of the lens array 506 when viewed from the photosensitive drum 103 side. FIG. 4(c2) is a schematic perspective view of the lens array 506. As shown in FIG. 4(c1), these lenses are arranged in two rows along the arrangement direction of the 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, and has an entrance surface on which the light emitted from the LEDs 503 is incident and an exit surface from which the light incident from the entrance surface exits. 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 prism such as a hexagonal prism.

[0040] The dotted line Z in Fig. 4(c2) indicates the optical axis of the lens. The optical print head 105 is moved by the above-mentioned movement mechanism 640 in a direction generally along the optical axis of the lens indicated by the dotted line Z. 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 has the role of focusing the light emitted from the LED 503 on the surface of the photosensitive drum 103.

[0041] 5 is a cross-sectional view of optical print head 105 cut perpendicularly to the longitudinal direction of optical print head 105. As shown in FIG. 5, substrate 502 and lens array 506 are held by holding member 505 so as to face each other. Holding member 505 is, for example, a plate material obtained by plating a galvanized steel plate or a cold-rolled steel plate. In this embodiment, holding member 505 is formed by bending a plate material into a U-shape. By using a metal plate material, costs can be suppressed, while strength can be achieved by performing bending processing.

[0042] However, the configuration of the holding member 505 is not limited to a configuration in which a metal plate material is bent, and may be, for example, so-called die casting. Die casting refers to a product manufactured by cooling and solidifying molten metal poured into a mold (cavity) or a manufacturing method thereof. When die casting is used as a manufacturing method, it is possible to handle complex shapes depending on the original mold. On the other hand, there is a disadvantage that there is no cost advantage when there is no need to mass-produce the same product because of the cost of making the mold. In this embodiment, the holding member 505 may be manufactured by bending a metal plate or may be manufactured by adopting die casting.

[0043] The lens array 506 forms a life-size erect image of the light beam emitted from the LED 503 on the photosensitive drum 103. At this time, the distance from the LED 503 to the light entrance surface 506b of the lens array 506 and the distance from the light exit surface 506a of the lens array 506 to the surface of the photosensitive drum 103 are substantially equal.

[0044] (Moving mechanism) Next, a mechanism for moving the optical print head 105 in conjunction with the sliding movement of the slide member 525 will be described with reference to FIG. 6. FIG. 6 is a view of the exposure unit 520 as seen from the left side. For ease of explanation, the support member 526 is not shown. FIG. 6(a) shows a state in which the optical print head 105 is located at an exposure position, which is a position when exposing the photosensitive drum 103. On the other hand, FIG. 6(b) shows a state in which the optical print head 105 is located at a retracted position retracted from the photosensitive drum 103 to the exposure position. Here, in this embodiment, the distance between the photosensitive drum 103 and the light emission surface of the lens array 506 when the optical print head 105 is located at the exposure position is about 3 mm.

[0045] As shown in FIG. 6, a link member 535 is rotatably connected to one end of the slide member 525 in the longitudinal direction of the slide member 525, and a link member 537 is rotatably connected to the other end of the slide member 525 in the longitudinal direction of the slide member 525. The slide member 525 slides from the front side to the back side in response to the rotation of a cover 558 (not shown) from a closed state to an open state. When the slide member 525 slides from the front side to the back side, the link member 535 and the link member 537 rotate counterclockwise as shown in FIG. 6. In addition, the link member 535 and the link member 536 are rotatably connected to each other. The link member 537 and the link member 538 are also rotatably connected to each other.

[0046] Since one end of the link member 536 is rotatably connected to the support member 526 (not shown), the link member 536 also rotates relative to the support member 526 in conjunction with the rotation of the link member 535. Furthermore, since one end of the link member 538 is rotatably connected to the support member 526 (not shown), the link member 538 also rotates relative to the support member 526 in conjunction with the rotation of the link member 537. When the slide member 525 moves from the front side to the back side, both the link member 536 and the link member 538 rotate clockwise relative to the support member 526. Here, the other end of the link member 535 is rotatably connected to the holding member 505, and the other end of the link member 537 is rotatably connected to the holding member 505. Therefore, in conjunction with the sliding movement of slide member 525 from the front side to the back side, link members 535 and 537 rotate counterclockwise, causing the other end side of link member 535 and the other end side of link member 537 to move in a direction away from photosensitive drum 103. In this way, optical print head 105 moves from the exposure position to the retracted position.

[0047] Next, the manner in which the optical print head 105 moves from the state shown in FIG. 6(b) to the state shown in FIG. 6(a), that is, from the retracted position to the exposure position in conjunction with the sliding movement of the sliding member 525, will be described.

[0048] The slide member 525 moves from the back side to the front side in conjunction with the rotation of the cover 558 (not shown) from an open state to a closed state. When the slide member slides from the back side to the front side, the link member 535 and the link member 537 rotate clockwise as shown in FIG. 6. At the same time, the link member 536 and the link member 538 rotate counterclockwise. When the slide member 525 slides from the back side to the front side, the link member 535 and the link member 537 rotate clockwise, so that the other end side of the link member 535 and the other end side of the link member 537 move in a direction approaching the photosensitive drum 103. In this way, the optical print head 105 moves from the retracted position to the exposure position. In this embodiment, the moving direction of the optical print head 105 moving between the retracted position and the exposure position is substantially the same as the optical axis direction of the lens array 506.

[0049] When holding member 505 of optical print head 105 moves from the retracted position toward the exposure position in conjunction with the sliding movement of slide member 525, abutment pin 514 provided on one end of holding member 505 in the longitudinal direction of holding member 505 and abutment pin 515 provided on the other end of holding member 505 abut against drum unit 518. In this way, the position of holding member 505 relative to drum unit 518, i.e., the position of optical print head 105, is determined.

[0050] When the position of the holding member 505 relative to the drum unit 518 is determined in this manner, the distance between the photosensitive drum 103 and the light exit surface of the lens array 506 is also determined, and the movement of the optical print head 105 to the exposure position is completed.

[0051] The mechanisms of the link mechanism 530 and the link mechanism 540 will be described in more detail with reference to Figures 7 and 8. Figure 7(a) is a schematic perspective view of the front side of the support member 526 as seen from the left side. Also, Figure 7(b) is a schematic perspective view of the front side of the support member 526 as seen from the right side. Below, the link mechanism 530 provided on the front side of the support member 526 will be described. The configuration of the link mechanism 540 is substantially the same as that of the link mechanism 530, and therefore a description thereof will be omitted.

[0052] 7, support member 526 includes support shaft 531 and E-type retaining ring 533. Holes through which support shaft 531 is inserted are formed in the right and left side wall surfaces of support member 526, which is machined into a U-shape. With support shaft 531 inserted through these holes, support shaft 531 is fixed to support member 526 by E-type retaining ring 533.

[0053] The sliding member 525 is a plate-like member made of metal. As shown in FIG. 7(a), a long hole 691 extending in the front-rear direction is formed in the sliding member 525. A support shaft 531 is inserted into this long hole 691. In this embodiment, the support shaft 531 is loosely fitted into the long hole 691 with a gap of about 0.1 to 0.5 mm in the up-down direction. The diameter of the long hole 691 in the longitudinal direction is about 350 mm. This allows the sliding member 525 to slide about 350 mm in the front-rear direction relative to the support member 526.

[0054] Further, an auxiliary member 539 is attached to one end side of the slide member 525 in the longitudinal direction of the slide member (the front side of the slide member 525). An accommodation space 562 is formed in the auxiliary member 539. A protrusion provided on the cover 558 is accommodated in the accommodation space 562. When the cover 558 rotates, the protrusion moving together with the rotating cover 558 hits the front side wall or the rear side wall of the accommodation space 562. The protrusion pushes the front side wall of the accommodation space 562, so that the slide member 525 moves to the front side. On the other hand, the protrusion pushes the rear side wall of the accommodation space 562, so that the slide member 525 moves to the rear side. In this way, the slide member 525 also moves in the front-rear direction in conjunction with the rotation of the cover 558.

[0055] The link mechanism 530 includes a link member 535 and a link member 536. Both the link member 535 and the link member 536 are longitudinal resin plates. A protrusion 655 (one example of a resin support portion and a resin first support portion) is formed on one end side (upper side in FIG. 7(a)) of the link member 535 in the longitudinal direction of the link member 535. Meanwhile, a tube portion 610 is formed on the other end side (lower side in FIG. 7(a)) of the link member 535 in the longitudinal direction of the link member 535. The protrusion 655 fits into an opening formed on the front side of the holding member 505. This allows the link member 536 to rotate relative to the holding member 505 with the protrusion 655 as the rotation center. The tube portion 610 is a hollow cylinder. In FIG. 7, a protrusion protruding from the slide member 525 fits into the tube portion 610. This allows the link member 536 to rotate relative to the slide member 525 as well.

[0056] Moreover, one end side in the longitudinal direction of link member 536 (the upper side in FIG. 7(b)) is rotatably attached to link member 535. That is, link member 535 and link member 536 are rotatable relative to each other. Meanwhile, the other end side in the longitudinal direction of link member 536 (the lower side in FIG. 7(b)) is rotatably attached to support member 526. Specifically, holes are formed in the lower side of link member 536 and in the left side wall surface of support member 526, and insertion pin 532 is inserted through this hole. In this way, link member 536 is rotatably fixed to support member 526.

[0057] FIG. 8 is a diagram for explaining the rotation of each of the link member 535 and the link member 536 of the link mechanism 530. As described above, the tube portion 610 formed in the link member 535 is fitted into the protrusion 534 formed in the support member 526. Therefore, when the slide member 525 slides from the front side to the back side, the link member 535 rotates clockwise as shown in FIG. 8 around the protrusion 534 as the rotation center. Since the link member 535 and the link member 536 are connected to each other so as to be rotatable, the link member 536 rotates counterclockwise relative to the slide member 525 in conjunction with the clockwise rotation of the link member 535. At this time, the link member 536 rotates relative to the support member 526 around the insertion pin 532 as the rotation center. The link member 535 rotates while being rotatably supported by the link member 536, so that the protrusion 655 of the link member 535 moves downward.

[0058] Here, if the distance between the rotation center axis of the link member 535 relative to the slide member 525 and the connection center axis of the link member 535 and the link member 536 is L1, the distance between the rotation center axis of the link member 536 relative to the support member 526 and the connection center axis of the link member 535 and the link member 536 is L2, and the distance between the rotation center axis of the link member 535 relative to the holding member 505 and the connection center axis of the link member 535 and the link member 536 is L3, L1 to L3 are equal to each other. In general, such a link mechanism is also called a Scott-Russell mechanism. By making the distances L1 to L3 equal, the movement direction of the protrusion 655 linked to the sliding movement of the slide member 525 becomes vertical. Specifically, the protrusion 655 moves on the dotted line A in FIG. 8(b). This allows the holding member 505 to move up and down in conjunction with the sliding movement of the slide member 525.

[0059] Furthermore, the configuration for moving the optical print head 105 to the exposure position and the retracted position is not limited to the configuration using the first link mechanism 530 and the second link mechanism 540, but may be the configuration using the moving mechanism 940 shown in Fig. 9. The moving mechanism 940 will be described below with reference to Fig. 9. Note that members having substantially the same functions as those constituting the moving mechanism 940 are denoted by the same reference numerals and may not be described repeatedly.

[0060] 9, a first cam portion 112 and a second cam portion 113 are provided on the front and rear sides of the slide member 525. In addition, a movement support portion 114 and a movement support portion 115 are provided on the front and rear sides of a holding member 505 of the optical print head 105. The first cam portion 112 and the second cam portion 113 have an inclined surface on the holding member 505 side that is inclined downward from the rear side to the front side.

[0061] 9A is a schematic diagram of the holding member 505 and the moving mechanism 940 located at the exposure position, as viewed from the right side. When the holding member 505 of the optical print head 105 is located at the exposure position, the slide member 525 slides from the front side to the rear side relative to the support member 526, and the first cam portion 112 and the second cam portion 113 provided on the slide member 525 move from the front side to the rear side relative to the support member 526 together with the slide member 525. As a result, the lower ends of the moving support portion 114 and the moving support portion 115 provided on the holding member 505 come into contact with the first cam portion 112 and the second cam portion 113, and the moving support portion 114 and the moving support portion 115 move along the first cam portion 112 and the second cam portion 113 in a direction from the exposure position to the retracted position.

[0062] 9B is a schematic diagram of the holding member 505 and the moving mechanism 940 in the retracted position, as viewed from the right side. When the holding member 505 of the optical print head 105 is in the retracted position, and the slide member 525 slides from the rear side to the front side relative to the support member 526, the first cam portion 112 and the second cam portion 113 provided on the slide member 525 slide from the rear side to the front side relative to the support member 526 together with the slide member 525. As a result, the lower ends of the moving support portion 114 and the moving support portion 115 provided on the holding member 505 are pushed up and moved along the first cam portion 112 and the second cam portion 113 in the direction from the retracted position to the exposure position.

[0063] (cleaning mechanism) The optical print head 105 is located near the photosensitive drum 103 and the developing unit 106. Therefore, toner may adhere to the light exit surface of the lens array 506. If dust such as toner adheres to the light exit surface of the lens array 506, part of the light traveling from the LED 503 toward the photosensitive drum 103 may be blocked, which may result in poor image formation. Therefore, it is necessary to periodically remove dirt adhering to the light exit surface of the lens array 506.

[0064] Therefore, a mechanism is known in which a rod-shaped cleaning rod is inserted and removed from the outside of the image forming apparatus 1 to clean the light exit surface of the lens array 506. FIG. 10 is a diagram showing a state in which a cleaning member 600 is inserted from the outside of the main body of the image forming apparatus 1. A plate-shaped blade is provided at the tip of the cleaning member 600, and when an operator inserts and removes the cleaning member 600 from the image forming apparatus 1, the blade rubs against the surface of the lens array 506. As shown in FIG. 10, an insertion portion 550 into which the cleaning member 600 is inserted is integrally provided with a support member 526 provided in the exposure unit 520. Here, the support member 526 is fixed to the main body of the image forming apparatus 1. Therefore, the support member 526 is also fixed to the main body of the image forming apparatus 1. The insertion portion 550 does not need to be provided in the support member 526, and may be formed in a member fixed to the main body of the image forming apparatus 1, for example, or may be formed in the drum unit 518.

[0065] As shown in FIG. 10, the insertion portion 550 has walls facing the right and left sides of the inserted cleaning member 600 in order to restrict the cleaning member 600 inserted into the insertion portion 550 from moving in the left-right direction. The upper parts of these walls are bent in an L-shape to include the cleaning member 600. This restricts the cleaning member 600 inserted into the insertion portion 550 from moving upward. In other words, the cleaning member 600 inserted into the insertion portion 550 is restricted by the insertion portion 550 from moving in a direction perpendicular to the direction in which the cleaning member 600 is inserted into and removed from the insertion portion 550 (the direction of the arrow in FIG. 10). In other words, the insertion portion 550 guides the movement of the cleaning member 600 in the direction indicated by the arrow in FIG. 10.

[0066] Here, when the cleaning member 600 is inserted into the insertion portion 550, there is a slight gap between the cleaning member 600 and the insertion portion 550. In this embodiment, the gap between the cleaning member 600 inserted into the insertion portion 550 and the insertion portion 550 in the left-right direction is about 2 mm. Also, in the up-down direction, there is a gap between the cleaning member 600 inserted into the insertion portion 550 and in contact with the bottom surface of the insertion portion 550 and the upper portion of the insertion portion 550 in the up-down direction, and the cleaning member 600 inserted into the insertion portion 550 and in contact with the bottom surface of the insertion portion 550, and the upper portion of the insertion portion 550. In this way, when the cleaning member 600 is inserted into the insertion portion 550, there is a slight gap between the cleaning member 600 and the insertion portion 550. This allows the operator to smoothly insert and remove the cleaning member 600 into and from the insertion portion 550.

[0067] However, if there is a slight gap between the cleaning member 600 and the insertion portion 550 in the vertical direction when the cleaning member 600 is inserted into the insertion portion 550, when an operator applies a downward force to the grip portion 603, the tip side of the cleaning member 600 may move upward with the insertion portion 550 as a fulcrum, and the cleaning portion 604 may move away from the light emission surface of the lens array 506. If an operator inserts or removes the cleaning member 600 into or from the insertion portion 550 in this state, there is a risk that the blade provided at the tip of the cleaning member 600 will not rub against the light emission surface of the lens array 506.

[0068] On the other hand, when the cleaning member 600 is inserted into the insertion portion 550, the narrower the gap between the cleaning member 600 and the insertion portion 550, the lower the operability when inserting the cleaning member 600 from the outside of the device body into the insertion portion 550. Specifically, by ensuring a certain degree of clearance between the cleaning member 600 and the insertion portion 550 when the cleaning member 600 is inserted into the insertion portion 550, the operator can easily insert the cleaning member 600 into the insertion portion 550.

[0069] (Earth mechanism) Since the holding member 505 is made of metal, it may become charged by, for example, the cleaning member 600 rubbing against the holding member 505. Since the holding member 505 holds the substrate 502, if the holding member 505 becomes charged, there is a risk that the electric charge will be discharged from the holding member 505 to the substrate 502. Therefore, the holding member 505 needs to be earthed.

[0070] 11 is a diagram for explaining the grounding mechanism in this embodiment. Metallic support member 526 is supported by front plate 642 provided on the front side of image forming apparatus 1 and rear plate 643 provided on the back side of image forming apparatus 1. Therefore, holding member 526 is grounded by either or both of front plate 642 and rear plate 643.

[0071] A metal leaf spring 701 is attached to the rear side of the holding member 526 by a screw 710. As shown in FIG. 11, the tip of the leaf spring 701 is in contact with the pin 515. The leaf spring 701 is elastically deformed, and the leaf spring 701 presses the pin 515 in the direction of the rotation axis of the photosensitive drum 103 by its restoring force. Specifically, the leaf spring 701 presses the pin 515 in the direction from the front side to the rear side of the image forming apparatus 1. Since the leaf spring 701 is always pressed against the pin 515 by its elastic force, the holding member 505 can be reliably grounded through the pin 515. In this embodiment, the spring 701 is used as a member for grounding the holding member 505, but a wire spring or the like may be used. That is, the leaf spring 701 corresponds to the first pressing member, and the pin 515 corresponds to the first pin. The leaf spring 703 corresponds to the second pressing member, and the pin 514 corresponds to the second pin.

[0072] FIG. 12 is a diagram for explaining the positional relationship between the pin 515 and the leaf spring 701 when the holding member 505 is located at the exposure position and the positional relationship between the pin 515 and the leaf spring 701 when the holding member 505 is located at the separation position. FIG. 12(a) is a diagram for explaining the positional relationship between the pin 515 and the leaf spring 701 when the holding member 505 is located at the exposure position, and FIG. 12(b) is a diagram for explaining the positional relationship between the pin 515 and the leaf spring 701 when the holding member 505 is located at the separation position. In both figures, the holding member 505 is not shown in order to simplify the explanation. As can be seen from these figures, even if the pin 515 moves together with the holding member 505 that moves between the exposure position and the separation position, the leaf spring 701 is always in contact with the pin 515. In other words, the pin 515 moves together with the holding member 505 while being in contact with the leaf spring 701. Therefore, the holding member 505 is always grounded via the pin 515.

[0073] When the holding member 505 is an elongated member as in this embodiment, it is desirable to ground it through multiple paths in order to stabilize the potential in the longitudinal direction. For this reason, in this embodiment, in addition to the pin 515, the pin 514 is also grounded using a similar configuration to ensure that the holding member 505 is grounded.

[0074] FIG. 13 is a diagram showing a configuration in which both pins 514 and 515 are grounded. As shown in FIG. 13, the leaf spring 703 is elastically deformed, and the leaf spring 703 presses the pin 514 in the direction of the rotation axis of the photosensitive drum 103 by its restoring force. That is, the leaf spring 703 corresponds to the first pressing member, and the leaf spring 701 corresponds to the second pressing member. The tip of the leaf spring 703 contacts the pin 514 in the same manner as the leaf spring 701. Since the leaf spring 703 presses the pin 514 by its restoring force due to elastic deformation, the leaf spring 703 always contacts the pin 514 even when the pin 515 moves together with the holding member 505 that moves between the exposure position and the separated position. In other words, the pin 514 moves together with the holding member 505 while always contacting the leaf spring 703. Therefore, the holding member 505 is always grounded via the pin 515.

[0075] (Optical print head positioning configuration) 14 shows leaf spring 703 pressing positioning pin 514 in the direction from back to front, and leaf spring 701 pressing positioning pin 515 in the direction from back to front. Optical print head 105 pressed by leaf springs 701 and 703 comes into contact with regulating member 550, thereby regulating its position in the direction of the rotation axis. Regulating member 550 is removable, and by removing it when installing or replacing optical print head 105, it does not interfere with the movement of optical print head 105. By regulating the position of optical print head 105, the position of optical print head 105 relative to drum unit 518 is also determined, making it possible to form a latent image at a predetermined position.

[0076] In this embodiment, the leaf spring 703 and the leaf spring 701 press toward the front side in the front-rear direction. That is, a plurality of pressing members press the optical print head 105 in the same direction, and the regulating member 550 regulates the movement in the pressing direction, thereby regulating the position of the optical print head 105 relative to the drum unit 518. In this case, when a plurality of pressing members press the optical print head 105 in different directions, the following problem occurs. First, when the leaf spring 701 and the leaf spring 703 press the optical print head 105 in different directions in the same direction, the optical print head 105 may not come into contact with the regulating member 550 due to the difference in the biasing force between the leaf spring 701 and the leaf spring 703, and the position of the optical print head 105 relative to the drum unit 518 may not be determined. Furthermore, consider the case where the leaf spring 701 and the leaf spring 703 press the optical print head 105 in different directions. For example, consider a case where leaf spring 701 presses pin 515 toward the front in the rotation axis direction, and leaf spring 703 presses pin 514 toward the right in the short side direction (left-right direction) perpendicular to the optical axis direction and rotation axis direction of optical print head 105. In this case, there is a risk that optical print head 105 will rotate in a plane defined by the rotation axis direction and the short side direction, and its position relative to drum unit 518 will not be determined to be a predetermined position.

[0077] In this embodiment, the leaf springs 701 and 703 press the optical print head 105 toward the front side in the front-rear direction, and the regulating member 550 regulates the movement of the optical print head 105 toward the front side in the front-rear direction, but the pressing direction of the pressing member is not limited to this. That is, the leaf springs 701 and 703 may press the optical print head 105 toward the rear side in the front-rear direction, or may press the optical print head 105 in the left-right direction, and it is sufficient that the leaf springs 701 and 703 press the optical print head 105 in the same direction.

[0078] In this embodiment, the regulating portion 550 regulates the position of the optical print head 105 in the front-rear direction by abutting against the positioning pin 514, but the abutment position is not limited to this and may be other positions as long as it can regulate the position of the optical print head 105 in the pressing direction of the leaf springs 701 and 703. In other words, the regulating member 550 may abut against the positioning pin 515 or the holding member 505, etc.

[0079] When the optical print head 105 pressed by the leaf springs 701 and 703 comes into contact with the regulating member 550, a rotational moment may be generated with respect to the optical print head 105, with the position regulating portion 705, which is the position of the regulating member 550 where the optical print head 105 comes into contact, as a fulcrum. The rotational moment is generated due to a difference in the vertical position between the position regulating portion 705 and the position where the leaf spring 703 presses the positioning pin 514. In this embodiment, the pressing position of the leaf springs 701 and 703 is defined as follows in order to reduce the positional deviation of the optical print head 105 caused by the rotational moment. In FIG. 14, the position of the position regulating portion 705 in the vertical direction is indicated by a dotted line A. At this time, the vertical direction corresponds to the moving direction of the optical print head 105. The leaf spring 703 presses the positioning pin 514 on the opposite side of the drum unit 518 to the position regulating portion 705 in the vertical direction. Furthermore, the leaf spring 701 presses the positioning pin 515 on the side where the drum unit 518 is provided with respect to the position restricting portion 705 in the vertical direction. By thus defining the pressing positions of the leaf springs 701 and 703 in the vertical direction, the rotation moment caused by the pressing of the leaf spring 701 with the position restricting portion 705 as the fulcrum and the rotation moment caused by the pressing of the leaf spring 703 with the position restricting portion 705 as the fulcrum are opposite in direction. In other words, it is possible to reduce the positional deviation of the optical print head 105 caused by the rotation moment caused by the pressing of the leaf spring. Note that in this embodiment, the leaf spring 703 presses the positioning pin 514 below the position restricting portion 705 and the leaf spring 701 presses the positioning pin 515 above the position restricting portion 705 in the vertical direction, but the opposite sides may be used. 15, the leaf spring 703 may press the positioning pin 514 above the position restricting portion 705, and the leaf spring 701 may press the positioning pin 515 below the position restricting portion 705. Alternatively, the leaf spring 701 and the leaf spring 703 may press either the upper side or the lower side of the position restricting portion 705 in the vertical direction.

[0080] In this embodiment, the leaf springs 701 and 703 press the optical print head 105 in the same direction, but the pressing directions are not limited to this and do not have to be completely the same. That is, it is sufficient that the leaf spring 703 has a force component pressing the optical print head 105 in the direction in which the leaf spring 701 presses the optical print head 105. Also, the leaf spring 701 may have a force component pressing the optical print head 105 in the direction in which the leaf spring 703 presses the optical print head 105. The direction in which the leaf springs 701 and 703 press the optical print head 105 corresponds to a predetermined direction.

[0081] In addition, in this embodiment, the leaf spring 701 contacts the pin 515 in a direction perpendicular to the optical axis of the lens array 506 (the direction of the rotation axis of the photosensitive drum 103). On the other hand, a configuration in which the holding member 505 is pressed in a direction along the optical axis can also be considered. However, in this configuration, if dust such as toner gets caught between the leaf spring 701 and the holding member 505, there is a risk that sufficient grounding cannot be achieved. On the other hand, if the leaf spring 701 presses the holding member 505 in a direction perpendicular to the optical axis direction of the lens array 506 as in this embodiment, the possibility that dust such as toner gets caught between the leaf spring 701 and the holding member 505 is low due to the action of gravity. Therefore, the direction in which the leaf spring 701 presses the pin 515 is preferably a direction perpendicular to the optical axis direction of the lens array 506.

[0082] Furthermore, since earthing is performed using the abutment pin 515 protruding from the holding member 505 toward the side opposite to the side where the photosensitive drum 103 is disposed with respect to the holding member 505 in the optical axis direction of the lens array 506, the length of the leaf spring 701 can be shortened. If the length of the leaf spring 701 is long, it becomes difficult to adjust the elastic force, and there is a risk of unnecessarily pressing the holding member 505. Furthermore, since earthing is performed using the abutment pin 515, the distance between the holding member 505 and the support member 526 does not increase significantly even if the amount of movement of the holding member 505 by the movement mechanism increases, so that the possibility of the earth path being interrupted can be reduced.

[0083] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0084] 1. Image forming device 103 Photosensitive drum 105 Optical print head 505 Retaining member 506 Lens Array 514 Abutment pin 515 Contact pin 550 Insertion part 600 Cleaning materials 701 Leaf spring 703 Leaf Spring

Claims

1. A rotating photoconductor; an optical print head having a substrate on which a plurality of light emitting units that emit light to expose the photosensitive member are arranged along a rotation axis direction of the photosensitive member, and a holding member that holds the substrate, the optical print head being movable between an exposure position where the photosensitive member is exposed and a retracted position retracted from the exposure position; a first pressing member that presses the optical print head in a predetermined direction; a second pressing member that presses the optical print head in the predetermined direction; a restricting portion that restricts movement of the optical print head in the predetermined direction; An image forming apparatus comprising:

2. the image forming apparatus has a rotation support member that rotatably supports the photoconductor, the optical print head has a first pin that contacts the rotary support member to determine a distance between the optical print head and the photosensitive member in the emission direction of light emitted by the light-emitting unit, and a second pin that contacts the rotary support member to determine a distance between the optical print head and the photosensitive member in the emission direction, the first pressing member presses the first pin, the second pressing member presses the second pin; 2. The image forming apparatus according to claim 1,

3. the first pin is made of metal, and the first pin and the holding member are electrically connected to each other; the second pin is made of metal, and the second pin and the holding member are electrically connected to each other; the first pressing member and the second pressing member are connected to ground; 3. The image forming apparatus according to claim 2,

4. the restricting portion restricts the movement of the optical print head in the predetermined direction by contacting the first pin; 3. The image forming apparatus according to claim 2,

5. the first pressing portion presses the first pin on a side opposite to the photoconductor with respect to the regulating portion in the emission direction; the second pressing portion presses the second pin on a side where the photoconductor is located with respect to the regulating portion in the emission direction; 5. The image forming apparatus according to claim 4.

6. the first pressing member has a force component for pressing the optical print head in the predetermined direction, and the second pressing member has a force component for pressing the optical print head in the predetermined direction; 2. The image forming apparatus according to claim 1,

7. The predetermined direction is along the longitudinal direction of the substrate.

2. The image forming apparatus according to claim 1,

8. the image forming apparatus has a housing that houses the photoconductor, the first pressing member, and the second pressing member; The optical print head is accommodated in the housing through an opening formed in the housing.

2. The image forming apparatus according to claim 1,

9. The plurality of light-emitting units are organic electroluminescent (EL).

2. The image forming apparatus according to claim 1,

Images