Image forming apparatus including optical print head

Abstract

To solve the problem in which: in an image forming apparatus comprising an optical print head movable to an exposure position where it exposes a photoreceptor and a retreat position where it is retreated from the exposure position, the optical print head may be brought into contact with projections on a moving path and prevented from moving to the exposure position.SOLUTION: In an image forming apparatus comprising an optical print head movable to an exposure position where it exposes a photoreceptor and a retreat position where it is retreated from the exposure position, a guide member guiding the optical print head has a first projection that defines the position of the optical print head at the exposure position and a second projection that is provided below the first projection. The second projection is elastically deformed in a direction orthogonal to an optical axis direction and a rotation axis direction.SELECTED DRAWING: Figure 15

Description

[Technical Field]

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

[0002] 2. Description of the Related Art Conventionally, in electrophotographic image forming apparatuses, a configuration is known in which the surface of a photosensitive member is exposed to light using an optical print head provided with a plurality of light-emitting elements such as LEDs.

[0003] The optical print head described above performs exposure in a position close to the photosensitive member. Therefore, when replacing the photosensitive member, the photosensitive member may come into contact with the optical print head. Patent Document 1 discloses a configuration in which the optical print head can be moved between an exposure position where the photosensitive member is exposed and a retracted position where the optical print head is retracted from the exposure position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-160435 Summary of the Invention [Problem to be solved by the invention]

[0005] In the image forming apparatus described above, there may be protrusions or the like on the path along which the optical print head moves from the retracted position to the exposure position. Due to dimensional errors during component manufacturing or assembly errors, the moving optical print head may come into contact with the protrusions, which may impede the movement of the optical print head.

[0006] In view of the above problems, an object of the present invention is to provide a configuration for reducing the risk of obstruction to the movement of an optical print head in an image forming apparatus equipped with an optical print head that can be moved between an exposure position and a retracted position. [Means for solving the problem]

[0007] The image forming apparatus of the present invention is characterized in that it comprises: a rotating photosensitive body; a plurality of light-emitting elements arranged along the rotational axis of the photosensitive body; and a lens that focuses light emitted by the plurality of light-emitting elements onto the surface of the photosensitive body; an optical print head that is movable between an exposure position where the photosensitive body is exposed to light and a retracted position where it is retracted from the exposure position; and a guide member that guides the optical print head, the guide member having a first protrusion that contacts the optical print head at the exposure position to determine the position of the optical print head at the exposure position, and a second protrusion that is provided upstream of the first protrusion in a first direction in which the optical print head moves from the retracted position to the exposure position, and the second protrusion elastically deforms in a second direction that is perpendicular to the first direction and the rotational axis. [Effects of the Invention]

[0008] According to the present invention, in an image forming apparatus having an optical print head that is movable between an exposure position and a retracted position, it is possible to reduce the risk of the movement of the optical print head being obstructed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an image forming apparatus 1 according to an embodiment. [Figure 2] 2 is a diagram showing an image forming unit 102 according to an embodiment and a frame portion supporting the image forming unit 102. FIG. [Figure 3] FIG. 2 is a diagram showing a drum unit 518 and a developing unit 641 according to the embodiment. [Figure 4] FIG. 2 is a perspective view of the image forming apparatus 1 when the front cover 6 according to the embodiment is in an open state. [Figure 5] FIG. 10 is a perspective view of the image forming apparatus 1 when the cartridge cover 558 according to the embodiment is in an open state. [Figure 6] FIG. 2 is a schematic perspective view of an optical print head 105 provided in the image forming apparatus 1 according to the embodiment. [Figure 7](a) is a diagram showing the configuration of the substrate 502 according to the embodiment, (b1) is a diagram showing the arrangement of the LED chips 639 according to the embodiment, (b2) is a diagram showing the arrangement of the LED chips 639 according to the embodiment, (c1) is a diagram showing the lens array 506 according to the embodiment, and (c2) is a diagram showing the lens array 506 according to the embodiment. [Figure 8] FIG. 1A is a diagram showing the configuration of a cleaning rod 801 according to an embodiment, and FIG. 1B is a diagram showing the configuration of a cleaning rod 801 according to an embodiment. [Figure 9] FIG. 8 is a diagram showing the configuration of a cleaning member 803 according to an embodiment. [Figure 10] FIG. 10 is a diagram showing a guide configuration for a cleaning rod 801 according to an embodiment. [Figure 11] 8A is a diagram showing the configuration of a guide member 808 according to the embodiment, and FIG. 8B is a diagram showing the configuration of a guide member 809 according to the embodiment. [Figure 12] 8A is a diagram showing a state in which a cleaning rod 801 according to the embodiment is inserted into a guide member 808, and FIG. 8B is a diagram showing a state in which a cleaning rod 801 according to the embodiment is inserted into a guide member 808. FIG. [Figure 13] FIG. 8(a) is a diagram showing a cleaning rod 801 and a guide member 809 according to the embodiment, and FIG. 8(b) is a cross-sectional view of the guide member 809 according to the embodiment. [Figure 14] 1A is a diagram showing the configuration of a cleaning member 803 according to an embodiment, and FIG. 1B is a diagram showing the configuration of a cleaning member 803 according to an embodiment. [Figure 15] FIG. 8 is a diagram illustrating a relationship between an optical print head 105 and a guide member 808 according to an example of the embodiment. [Figure 16] 1A is a diagram showing the relationship between the optical print head 105 and the guide member 808 at the retracted position according to an embodiment; FIG. 1B is a diagram showing the relationship between the optical print head 105 and the guide member 808 at the mid-movement position according to an embodiment; and FIG. 1C is a diagram showing the relationship between the optical print head 105 and the guide member 808 at the exposure position according to an embodiment. [Figure 17] FIG. 8 is a diagram showing the relationship between the optical print head 105 and a guide member 808 according to the embodiment. [Figure 18]8A and 8B are diagrams showing the relationship between a cleaning rod 801 and a guide member 808 according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. However, the components described in this description are merely examples, and the present invention is not limited to the embodiments described in this description.

[0011] (Image forming device) First, a schematic configuration of the image forming apparatus 1 will be described. FIG. 1 is a schematic cross-sectional view of the image forming apparatus 1. The image forming apparatus 1 shown in FIG. 1 is a color printer (MFP: Multi Function Peripheral) equipped with a reading device, but the embodiment may also be a copier that does not have a reading device. Furthermore, the embodiment is not limited to a so-called tandem color image forming apparatus equipped with multiple photosensitive drums 103 as shown in FIG. 1, but may also be a color image forming apparatus equipped with a single photosensitive drum 103 or an image forming apparatus that forms monochrome images.

[0012] The image forming apparatus 1 shown in FIG. 1 includes four image forming units 102Y, 102M, 102C, and 102K (hereinafter collectively referred to as "image forming unit 102") that form toner images of yellow, magenta, cyan, and black, respectively. The image forming units 102Y, 102M, 102C, and 102K also include photosensitive drums 103Y, 103M, 103C, and 103K (hereinafter collectively referred to as "photosensitive drum 103"). These photosensitive drums are spaced apart from one another. The image forming units 102Y, 102M, 102C, and 102K also 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. In addition, the image forming units 102Y, 102M, 102C, and 102K are equipped with LED (Light Emitting Diode, hereinafter referred to as LED) exposure units 500Y, 500M, 500C, and 500K (hereinafter collectively referred to as "exposure units 500") as exposure light sources that emit light to expose the photosensitive drums 103Y, 103M, 103C, and 103K.

[0013] The image forming units 102Y, 102M, 102C, and 102K are equipped with developing units 106Y, 106M, 106C, and 106K (hereinafter collectively referred to as "developing units 106") that develop the electrostatic latent image on the photosensitive drum 103 with toner and develop toner images of the respective colors on the photosensitive drum 103. The letters Y, M, C, and K attached to the reference numerals indicate the colors of the toner.

[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) that 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 that 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 that fixes the secondarily transferred image onto the recording material S.

[0015] After the primary transfer, toner that was not transferred to the intermediate transfer belt remains on the surfaces of the photosensitive drums 103Y, 103M, 103C, and 103K. This residual toner is removed by drum cleaning devices (first cleaning devices) 8Y, 8M, 8C, and 8K (hereinafter collectively referred to as "drum cleaning devices 8") and collected in the collected toner container 5.

[0016] Furthermore, toner that has not been transferred to the recording material S remains on the surface of the intermediate transfer belt 107 after the secondary transfer. This residual toner is removed by a belt cleaning device (second cleaning device) 7 and collected in a collected toner container 5.

[0017] (Image formation process) The exposure unit 500Y exposes the surface of the photosensitive drum 103Y, which has been charged by the charger 104Y. As a result, an electrostatic latent image is formed on the photosensitive drum 103Y. Next, the developing unit 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 transferred to the intermediate transfer belt 107 in a similar image formation process.

[0018] 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 images onto the recording material S. The toner images transported to the secondary transfer section T2 are transferred onto the recording material S transported from a paper feed section (paper feed cassette) 101 by the transfer bias of the secondary transfer roller 109.

[0019] The recording material S is stored in a stack in the paper feed unit 101 and is fed to the conveying path 20 in accordance with the image formation timing. The paper feeding method involves first flipping up the leading edge of the recording material S due to friction of the paper feed roller 80, and then conveying only one sheet of recording material S to the conveying path 20 by a pair of paper separating conveying rollers 9a and 9b to prevent double feeding of the recording material S. The recording material S is then pulled out by a pair of conveying rollers 10a and 10b, passes through the conveying path 20, and is conveyed to a pair of registration rollers 11a and 11b, where it is stopped temporarily. Note that the pair of registration rollers 11a and 11b perform skew correction and timing correction before conveying to the secondary transfer unit T2.

[0020] The recording material S onto which the toner image has been transferred at the secondary transfer unit T2 is conveyed to the fixing unit 100. The fixing unit 100 fixes the toner image onto the recording material S by heat and pressure. The recording material S that has been subjected to the fixing process by the fixing unit 100 is discharged to the paper discharge unit 111.

[0021] As shown in FIG. 1 , the image forming apparatus 1 also includes toner containers 4Y, 4M, 4C, and 4K (hereinafter, also collectively referred to as "toner container 4"). When image formation is performed, the amount of toner in a developing unit 641 (described later) decreases. When this occurs, toner is supplied to the developing unit 641 (described later) from toner containers 4Y, 4M, 4C, and 4K provided corresponding to the image forming sections 102Y, 102M, 102C, and 102K via pipes (not shown). That is, the developing unit 641 (described later) included in the image forming apparatus 1 described in this embodiment replenishes new toner from the toner container 4, while transporting a portion of the excess toner to a collected toner container 5 as residual toner.

[0022] (Drum unit and developing unit) A drum unit 518, which is an example of a replaceable replacement unit, is attached to the image forming apparatus 1 of this embodiment. 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 (Y, M, C, K) of this embodiment includes photosensitive drums 103 (Y, M, C, K) rotatably supported on a frame of the drum unit 518.

[0023] The image forming apparatus 1 of this embodiment is also equipped with a developing unit 641 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 and a toner storage unit are integrated. The developing device 106 includes a developing sleeve, which is a developer carrier that carries developer. The developing unit 641 is provided with multiple gears for rotating a screw that mixes 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. A certain amount of toner is removed from the developing unit 641 as residual toner and transported to the recovered toner container 5. The drum unit 518 and the developing unit 641 may be implemented as a process cartridge in which the drum unit 518 and the developing unit 641 are integrated.

[0024] FIG. 2 is a perspective view of the image forming apparatus 1, showing only peripheral components of the image forming unit 102 and a frame portion that supports the components.

[0025] 3 is a further enlarged perspective view of the image forming section 102 in FIG. 2. In FIG. 3, a drum unit 518 and a developing unit 641 that the image forming apparatus 1 includes are shown.

[0026] As shown in Fig. 3, the image forming apparatus 1 includes a front plate 642 made of sheet metal and a rear plate 643 also made of sheet metal. The front plate 642 is a side wall provided on the front side of the image forming apparatus 1. The rear plate 643 is a side wall provided on the rear side of the image forming apparatus 1. As shown in Fig. 3, the front plate 642 and the rear plate 643 are disposed facing each other, with a metal beam (not shown) serving as a bridge between them. The front plate 642, the rear plate 643, and the beam (not shown) each form part of the frame of the image forming apparatus 1.

[0027] An opening is formed in front side plate 642 so that drum unit 518 and developing unit 641 can be inserted and removed from the front side of image forming apparatus 1. Drum unit 518 and developing unit 641 are attached to predetermined positions in the main body of image forming apparatus 1 through the opening.

[0028] Next, a more detailed description will be given of how to insert and remove drum unit 518 and developing unit 641, which are parts that need to be replaced periodically, from image forming apparatus 1.

[0029] 4 is a perspective view of the image forming apparatus 1 when the front cover 6 is in an open state. The front cover 6 is provided on the front side of the main body of the image forming apparatus 1. When performing maintenance, a user or an operator such as a service technician opens the front cover 6 to begin work.

[0030] 5 is a perspective view of the image forming apparatus 1 with the cartridge cover 558 in an open state. The cartridge covers 558 (Y, M, C, K) are covers that cover the front sides of both the drum unit 518 and the developing unit 641 that are installed in the installation position. One end of the cartridge cover 558 is fixed to the image forming apparatus 1 main body by a hinge, and the cartridge cover 558 is rotatable relative to the image forming apparatus 1 main body by the hinge. A worker performing maintenance opens the cartridge cover 558 and removes the drum unit 518 or the developing unit 641 from the main body.

[0031] In the following description, the side of the front plate 642 is defined as the front side, and the side of the rear plate 643 is defined as the rear side. Furthermore, when the photosensitive drum 103K on which the electrostatic latent image for the black toner image is formed is used as a reference, the side on which the photosensitive drum 103Y on which the electrostatic latent image for the yellow toner image is formed is defined as the left side. When the photosensitive drum 103Y on which the electrostatic latent image for the yellow toner image is formed is used as a reference, the side on which the photosensitive drum 103K on which the electrostatic latent image for the black toner image is formed is defined as the right side. Furthermore, the direction perpendicular to the front-rear and left-right directions defined here and pointing vertically upward is defined as the up direction, and the direction perpendicular to the front-rear and left-right directions defined here and pointing vertically downward is defined as the down direction.

[0032] In the following description, one end of the photosensitive drum 103 in the direction of its rotation axis means the front side as defined herein, and the other end means the rear side as defined herein. The one end and the other end in the front-rear direction also correspond to the front side and the rear side as defined herein. The one end in the left-right direction means the right side as defined herein, and the other end means the left side as defined herein.

[0033] In this embodiment, the toner (developer) contained in the toner container (developing container) is a two-component developer made by mixing a negatively charged non-magnetic toner and a magnetic carrier. The non-magnetic toner is a resin such as polyester or styrene that contains colorants, wax components, etc., and is then pulverized or polymerized to form a powder. In this embodiment, a toner with an average particle size of 5 μm is used. The magnetic carrier is a core made of resin particles kneaded with ferrite particles or magnetic powder, with a resin coating on the surface.

[0034] (Basic optical print head configuration) 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. Figure 6 is a schematic perspective view of the optical print head 105 included in the image forming apparatus 1 of this embodiment.

[0035] As shown in FIG. 6, the optical print head 105 includes a lens array 506 , a lens mounting portion 701 , and a holder 505 that holds a substrate 502 .

[0036] Next, the substrate 502 held by the holder 505 will be described. Fig. 7(a) is a schematic perspective view of the substrate 502. Fig. 7(b1) shows the arrangement of a plurality of LEDs 503 provided on the substrate 502. Fig. 7(b2) is an enlarged view of Fig. 7(b1).

[0037] An LED chip 639 is mounted on the substrate 502. As shown in FIG. 7(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. Wiring is provided on the substrate 502 for supplying signals to each LED chip 639. One end of a flexible flat cable (FFC) 160 (not shown), which is an example of a cable, is connected to the connector 504.

[0038] The main body of the image forming apparatus 1 is provided with a substrate having a control unit and a connector. The other end of the FFC 160 is connected to the connector. That is, the FFC 160 electrically connects the control unit and the substrate 502. A control signal (drive signal) is input to the substrate 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 substrate 502.

[0039] The LED chip 639 mounted on the substrate 502 will be described in more detail. As shown in FIGS. 7(b1) and 7(b2), 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 along its longitudinal direction. The center-to-center distance k2 between adjacent LEDs 503 along 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 503 of the LED chips 639-1 to 639-29 are arranged in a row along the longitudinal direction of the LED chip 639 such that the center-to-center distance between adjacent LEDs 503 is 21.16 μm. Therefore, the exposure range of the optical print head 105 of this embodiment is approximately 314 mm. The photosensitive layer of the photosensitive drum 103 is formed with a width of 314 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 that allows images to be formed on A4 size recording paper and A3 size recording paper.

[0040] The LED chips 639-1 to 639-29 are alternately arranged in two rows along the rotational axis direction of the photosensitive drum 103. That is, as shown in FIG. 7(b1), the odd-numbered LED chips 639-1, 639-3, ..., 639-29 counting from the left 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. 7(b2), the center-to-center distance k1 between the LEDs arranged between one end of one LED chip 639 and the other end of the other LED chip 639 in adjacent different LED chips 639 in the longitudinal direction of the LED chips 639 can be made equal to the center-to-center distance k2 between adjacent LEDs 503 on one LED chip 639. Although the present embodiment illustrates a configuration in which the LED 503 is used as the exposure light source, an organic EL (Organic Electro Luminescence) may also be used as the exposure light source.

[0041] Next, the lens array 506 will be described. Fig. 7(c1) is a schematic diagram of the lens array 506 when viewed from the photosensitive drum 103 side. Fig. 7(c2) is a schematic perspective view of the lens array 506. As shown in Fig. 7(c1), a plurality of 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 contact both of the adjacent lenses in the arrangement direction of the lenses in the other row. Each lens is a cylindrical glass rod lens. Note that the material of the lenses is not limited to glass and may be plastic. The shape of the lenses is also not limited to cylindrical and may be a polygonal prism, for example, a hexagonal prism.

[0042] The dotted line Z in Figure 7(c2) indicates the optical axis of the lens. The optical print head 105 can be moved in a direction (up and down) generally along the optical axis of the lens indicated by the dotted line Z by a movement mechanism (not shown). The optical axis of the lens here refers to the line connecting the center of the light exit surface of the lens and the focal point of the lens. The light emitted from the LED 503 is incident on the lens provided in the lens array 506. The lens has the function of focusing the incident light on the surface of the photosensitive drum 103. When assembling the optical print head 105, the attachment position of the lens array 506 with respect to the lens attachment part 701 (see Figure 6) is adjusted so that the distance between the light-emitting surface of the LED 503 and the light entrance surface of the lens is approximately equal to the distance between the light exit surface of the lens and the surface of the photosensitive drum 103.

[0043] (Cleaning rod configuration) Next, the configuration of cleaning rod 801 will be described.

[0044] In the image forming apparatus 1, an exposure unit such as the optical print head 105 is provided between the charger 104 and the developer 106. Therefore, the light exit surface of the lens array 506 included in the optical print head 105 may become contaminated by toner that has fallen from the photosensitive drum 103 or the developer 106. Contamination on the light exit surface of the lens array 506 may partially block light emitted from the light-emitting elements, which is one cause of deterioration in the quality of the output image. For this reason, it is desirable to periodically clean the light exit surface of the optical print head 105.

[0045] 8(a) is a schematic perspective view of the cleaning rod 801. Here, the direction (short-side direction, X direction) perpendicular to the longitudinal direction (Y direction) of the optical print head 105 and perpendicular to the optical axis direction (Z direction) is defined as the second direction, and the optical axis direction (Z direction) is defined as the first direction. The cleaning rod 801 has a gripping portion 802 at one end (rear end) in the longitudinal direction (Y direction) of the cleaning rod 801 that is gripped by an operator during cleaning work. The cleaning rod 801 has a function of removing foreign matter adhering to the surface of the lens array 506. The cleaning rod 801 has a cleaning member 803 that rubs against the surface of the lens array 506.

[0046] FIG. 8(b) is an enlarged view of one end of cleaning rod 801 in the longitudinal direction. FIG. 9 is a view of the tip end of cleaning rod 801 as viewed from below. Cleaning members 803a and 803b are provided on the underside of cleaning rod 801. Cleaning members 803a and 803b have the function of rubbing against and cleaning the surface of lens array 506. Two cleaning members 803a and 803b are arranged at different positions along the longitudinal direction of cleaning rod 801. The number of cleaning members 803 is not limited to two, and three or more may be arranged.

[0047] Pressing member 804 is a member for fixing cleaning member 803 and is provided on the tip side of cleaning rod 801. Furthermore, cleaning rod 801 is provided with elastic portion 805. Elastic portion 805 has the function of adjusting the force with which cleaning member 803 is pressed against lens 506 when cleaning rod 801 is inserted into image forming apparatus 1 by elastically deforming. It has the function of engaging with guide member 809 to regulate the position of cleaning rod 801. In other words, elastic portion 805 corresponds to the first elastic portion. Elastic portion 805 has different rigidity in the second direction and the first direction, and is lower in rigidity in the second direction than in the first direction. Specifically, when viewed in the longitudinal direction of elastic portion 805, the cross section of elastic portion 805 is rectangular, and the thickness in the second direction is thinner than the thickness in the first direction.

[0048] Furthermore, cleaning rod 801 is provided with protrusion 806 that protrudes in a second direction. Protrusion 806 has the function of engaging with guide member 809 to regulate the position of cleaning rod 801. In other words, protrusion 806 corresponds to the first protrusion. Protrusion 806 is provided on elastic portion 805. Furthermore, cleaning rod 801 is provided with guide member 807. Guide member 807 has the function of reinforcing cleaning rod 801 to reduce the risk of damage to cleaning rod 801 if an unexpected force is applied to cleaning rod 801. Guide member 807 is, for example, a metal plate made of a metallic material.

[0049] (Cleaning rod guide configuration) Next, we will explain the guide structure for cleaning rod 801. Cleaning rod 801 is inserted from the outside of image forming apparatus 1 and moved by the user along the longitudinal direction of lens array 506. At this time, cleaning member 803 rubs against the surface of lens array 506, removing foreign matter adhering to the surface of lens array 506.

[0050] 10 is a diagram showing the positional relationship between guide member 808, guide member 809, and cleaning rod 801. Guide member 808 functions as a guide that regulates the position of inserted cleaning rod 801. Guide member 809 functions as a guide member that guides inserted cleaning rod 801 along the longitudinal direction of optical print head 105. In other words, guide member 808 corresponds to the first guide member, and guide member 809 corresponds to the second guide member.

[0051] The guide members 808 and 809 are respectively provided on the frame of the image forming apparatus 1, which is the housing.

[0052] Guide member 808 and guide member 809 are provided at different positions in the insertion direction of cleaning rod 801. Specifically, guide member 808 is provided on the upstream side in the insertion direction of cleaning rod 801, and guide member 809 is arranged on the downstream side.

[0053] FIG. 11(a) is a detailed view of guide member 808. Guide member 808 includes restricting portion 810, restricting portion 813, and restricting portion 814. Restricting portion 810 has a function of restricting the position of inserted cleaning rod 801 in the second direction, and restricting portion 813 and restricting portion 814 have a function of restricting the position of inserted cleaning rod 801 in the first direction. Note that restricting portion 814 is provided upstream of restricting portion 813 in the insertion direction in which cleaning rod 801 is inserted. That is, restricting portion 810 corresponds to the first restricting portion, restricting portion 813 corresponds to the third restricting portion, and restricting portion 814 corresponds to the fourth restricting portion. In the second direction, the width of cleaning rod 801 including protruding portion 806 is greater than the width of restricting portion 810. Guide member 808 also includes a contact portion 815. When cleaning rod 801 is inserted, contact portion 815 contacts wall 822 provided on cleaning rod 801, thereby restricting the position of cleaning rod 801 in the insertion direction.

[0054] 11(b), guide member 809 has restricting portion 811 that restricts cleaning rod 801 in a first direction that is perpendicular to the second direction. Guide member 809 has inclined portion 812 that guides cleaning rod 801. Inclined portion 812 is provided at the end of guide member 809 on the guide member 808 side.

[0055] (Cleaning operation) 9, cleaning member 803 is provided on the lower side of cleaning rod 801 at the tip end side (the other end side in the rotational axis direction of photosensitive drum 103). Cleaning member 803 functions as a cleaning member that scrapes off and cleans toner and other contaminants that have fallen on the light-emitting surface of lens array 506. Cleaning member 803 is an elastically deformable member made of rubber such as sponge or elastomer. Furthermore, cleaning member 803 only needs to be able to wipe off toner and other contaminants that have fallen on the light-emitting surface of lens array 506, and may be a nonwoven fabric made of fibers such as cotton, nylon, or polyester.

[0056] FIG. 12(a) is a diagram showing a state in which cleaning rod 801 has been inserted into guide member 808 provided in image forming apparatus 1. FIG. 12(b) is a top view of cleaning rod 801 inserted into guide member 808. When an operator inserts cleaning rod 801 into guide member 808, protrusion 806 abuts against restricting portion 810. The width of cleaning rod 801, including protrusion 806, is wider than that of first restricting portion 810. Therefore, when protrusion 806 abuts against restricting portion 810, protrusion 806 elastically deforms in the second direction of first elastic portion 805, and cleaning rod 801 is inserted while abutting against restricting portion 810. This allows the operator to insert cleaning rod 801 while restricting the position of cleaning rod 801 in the second direction. When the tip of cleaning rod 801 passes through guide member 808, protrusion 806 returns to its position before elastic deformation. Thereafter, the cleaning member 803 comes into contact with the light emitting surface of the lens array 506 and starts cleaning the surface of the lens array 506 .

[0057] 13(a) is a diagram showing the state immediately before cleaning rod 801 is inserted into guide member 809 provided in image forming apparatus 1. FIG. 13(b) is a top view showing the state immediately before cleaning rod 801 is inserted into guide member 809 provided in image forming apparatus 1. Guide member 809 is provided further back than guide member 808. Guide member 809 is also arranged along the longitudinal direction of optical print head 105.

[0058] As shown in FIG. 13( a), guide member 809 has an inclined portion 812 at its end facing guide member 808. Inclined portion 812 is shaped to slope downward as it approaches the insertion direction of cleaning rod 801, and protruding portion 806 engages with it as cleaning rod 801 is inserted. As a result, when an operator inserts cleaning rod 801 into guide member 809, protruding portion 806 engages with inclined portion 812, and protruding portion 806 is guided and led into guide member 809. This allows the operator to easily insert cleaning rod 801 into guide member 809.

[0059] FIG. 13(b) is a diagram showing the cross-sectional shape of guide member 809. As shown in FIG. 13(b), guide member 809 has a U-shaped cross section and includes restricting portion 811. Restricting portion 811 is a wall provided on the upper side in the first direction, and has the function of restricting upward movement of cleaning rod 801 by engaging with protruding portion 806. This allows cleaning rod 801 to be inserted without cleaning member 803 separating from the light exit surface of lens array 506, and the entire light exit surface of lens array 506 can be reliably cleaned in the longitudinal direction.

[0060] Therefore, by using guide members 808 and 809 to regulate the position of cleaning rod 801 during insertion and cleaning, cleaning member 803 will not come off the lens surface even if the worker applies force, and cleaning can be performed reliably.

[0061] Furthermore, by making the opening of the regulating portion 810 smaller, space can be saved, and even if the distance between the photosensitive drums 103 of each color becomes narrow, the guide member 808 can be arranged for each color. Furthermore, when an operator inserts the cleaning rod 801, it is possible to regulate vibration in the second direction.

[0062] As described above, guide member 809 is provided further back than guide member 808, and the position of cleaning rod 801 in the first direction is restricted by restricting portion 813 provided on guide member 808. As cleaning rod 801 is inserted further back, protrusion 806 comes into contact with restricting portion 811 provided on guide member 809 arranged along optical print head 105, thereby preventing cleaning rod 801 from floating up at the back.

[0063] 14(a) is a cross-sectional view of cleaning member 803 near the tip of cleaning rod 801 just before protrusion 806 abuts against restriction portion 811 provided on guide member 809. Cleaning rod 801 has two cleaning members 803 arranged at different positions in the optical axis direction of the light exit surface of optical print head 105.

[0064] 14(b) shows a state in which the tip of cleaning rod 801 is slightly raised. At this time, cleaning member 803, which is positioned close to the light emission surface of optical print head 105, can clean the lens surface without coming off.

[0065] (Cleaning and lifting operations) Next, the relationship between the guide member 808 and the optical print head 105 in this embodiment will be described with reference to Figures 15 and 16(a), 16(b), and 16(c). Figure 15 is an enlarged perspective view of the guide member 808 and the optical print head 105 when it has moved to the retracted position. Figures 16(a), 16(b), and 16(c) are cross-sectional views of the guide member 808 and the optical print head 105 when it has moved to the retracted position, mid-movement position, and exposure position, respectively, as seen from the rear of the apparatus main body.

[0066] Guide member 808 has elastic portion 816, which elastically deforms in the second direction, below restricting portion 813. Elastic portion 816 has protruding portion 817 at its tip, which protrudes toward cleaning rod 801 in the second direction. Elastic portion 816 extends in the longitudinal direction of optical print head 105, but may also extend in the optical axis direction. Protruding portion 817 has inclined portions 818 and 819 in the longitudinal and optical axis directions of cleaning rod 801, respectively. Guide member 808 also has urethane sheet member 823 attached with double-sided tape (not shown) to seal the space between elastically deformable elastic portion 816 and restricting portion 813. This prevents toner carried by airflow from entering through gaps in guide member 808 due to the provision of second elastic portion 816 and adhering to lens array 506 of optical print head 105. The material of sheet member 823 is not limited to urethane; any stretchable material that does not inhibit the elastic deformation of the second elastic portion may be used.

[0067] When the optical print head 105 moves from the retracted position to the exposure position, the holding portion 505 abuts against the regulating portion 813, restricting movement to the exposure position, which may prevent the optical print head 105 from moving to the exposure position.

[0068] On the other hand, consider a case where elastic portion 816 is provided on the movement path of optical print head 105. As optical print head 105 moves from the retracted position to the exposure position, optical print head 105 comes into contact with elastic portion 816, causing elastic portion 816 to elastically deform in the second direction. Optical print head 105 then comes into contact with the tip of protrusion 817 provided on elastic portion 816. The position of optical print head 105 in the second direction is restricted by the restoring force of elastic portion 816 that has elastically deformed. As a result, optical print head 105 can move to the exposure position without being hindered by restriction portion 813. In other words, protrusion 817 corresponds to the second protrusion.

[0069] Furthermore, when the optical print head 105 moves from the retracted position to the exposure position, if the optical print head 105 passes through the restricting portion 813, the side surface of the holding portion 505 comes into contact with the restricting portion 813. As a result, the position of the optical print head 105 in the second direction is regulated, that is, the restricting portion 813 corresponds to the first protrusion.

[0070] Next, the positional relationship between restricting portion 813 and protruding portion 817 in the optical axis direction will be described in detail using Figure 17. Figure 17 is an enlarged cross-sectional view of the state in Figure 16(b). The separation distance h1 between restricting portion 813 and protruding portion 817 in the optical axis direction must be shorter than the distance obtained by subtracting the curved surface R of the bent portion from the height h2 of holder 505, and the relationship h2-R>h1 must be satisfied.

[0071] Next, the positional relationship between the restricting portion 813 and the protruding portion 817 in the step direction will be described in detail using Figure 17. Figure 17 is an enlarged cross-sectional view of the state in Figure 16(b). The positional relationship between the protruding height d1 of the restricting portion 813 and the protruding height d2 of the protruding portion 817 in the step direction must be d1 > d2, so that the protruding portion 817 does not protrude beyond the restricting portion 813 within a tolerance. This prevents the edge of the holder 505 from hitting the upper part of the protruding portion 817 when the optical print head 105 is retracted from the exposure position to the retracted position, which would hinder the movement of the optical print head 105 to the retracted position.

[0072] Next, the operation of the protrusion 817 during cleaning will be described with reference to FIGS. 18(a) and 18(b). FIG. 18(a) is a diagram showing the state in which the cleaning rod 801 is inserted into the guide member 808 and before the cleaning rod 801 comes into contact with the protrusion 817. FIG. 18(b) is a diagram and cross-sectional view of the cleaning rod 801 in contact with the protrusion 817. The cleaning rod 801 comes into contact with the inclined portion 818 provided on the protrusion 817, causing the elastic portion 816 to elastically deform, and the protrusion 817 retracts. The same applies to the shape of the support portion 824 protruding from the cleaning rod 801. At this time, the sheet member 823 provided on the back surface of the protrusion 817 also deforms simultaneously with the protrusion 817. Therefore, the cleaning rod 801 can clean the light exit surface of the lens array 506 without the protrusion 817 blocking the path of the cleaning rod 801.

[0073] As described above, in this embodiment, guide member 808 is provided with elastic member 816 that elastically deforms in the second direction. The restoring force of elastic member 816 after elastic deformation makes it possible to restrict the position of optical print head 105 in the second direction as it moves from the retracted position to the exposure position. As a result, it is possible to reduce the risk that optical print head 105 will come into contact with restricting portion 813 and be prevented from moving from the retracted position to the exposure position. [Explanation of symbols]

[0074] 105 Optical print head 105 505 Holding body 505 506 Lens Array 506 800 cabinets 801 Cleaning rod 802 Gripping part 803 Cleaning materials 804 Holding member 805 First elastic part 806 First protrusion 807 Guide member 808 First guide member 809 Second guide member 810 First Regulatory Department 811 Second Regulatory Department 812 First inclined section 813 Third Regulatory Department 814 Fourth Regulatory Department 815 Contact part 816 Second elastic part 817 Second protrusion 818 Second Slope 819 Third Slope 823 Sheet material 824 Support part

Claims

1. A rotating photoreceptor; an optical print head having a plurality of light-emitting units arranged along the rotation axis direction of the photosensitive member and a lens that focuses light emitted by the plurality of light-emitting units onto the surface of the photosensitive member, the optical print head being movable between an exposure position where the photosensitive member is exposed to light and a retracted position where the retracted position is retracted from the exposure position; a guide member for guiding the optical print head, the guide member having a first protrusion that contacts the optical print head at the exposure position to define the position of the optical print head at the exposure position, and a second protrusion that is provided upstream of the first protrusion in a first direction in which the optical print head moves from the retracted position to the exposure position; Equipped with The image forming apparatus according to claim 1, wherein the second protrusion is elastically deformed in a second direction perpendicular to the first direction and the direction of the rotation axis.

2. 2. The image forming apparatus according to claim 1, wherein the first protrusion and the optical print head come into contact with each other when the optical print head is located at the exposure position.

3. 3. The image forming apparatus according to claim 2, wherein the second protrusion and the optical print head come into contact with each other when the optical print head is located at the exposure position.

4. The image forming apparatus according to claim 1 , further comprising a cleaning rod that is inserted from the outside of the image forming apparatus and moves along the rotation axis direction to rub the surface of the lens.

5. When the cleaning rod is inserted into the image forming apparatus, the first protrusion and the cleaning rod come into contact with each other, the first protrusion contacts the cleaning rod to restrict the position of the cleaning rod in the first direction; 5. The image forming apparatus according to claim 4.

6. 6. The image forming apparatus according to claim 5, wherein when the cleaning rod is inserted into the image forming apparatus, the second protrusion comes into contact with the cleaning rod and elastically deforms in the second direction.

7. 2. The image forming apparatus according to claim 1, wherein the plurality of light emitting units are organic EL units.

Images