Image forming device

Abstract

To increase the vibration rigidity of a scanner unit with a simple configuration.SOLUTION: An image forming apparatus comprises: a scanner frame 51 that forms a space for accommodating therein at least part of a laser scanner 21; a scanner stay 50 that is provided along a rotation axis direction of a photoconductor drum inside the space of the scanner frame 51, and supports the laser scanner 21; a right frame 70 that is fixed to one end of the scanner frame 51 in the rotation axis direction; and a left frame 71 that is fixed to the other end of the scanner frame 51 in the rotation axis direction. The scanner stay 50 is fixed to the right frame 70 at one end and fixed to the left frame 71 at the other end in the rotation axis direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Image forming devices using electrophotographic image formation processes form latent images by scanning a laser beam emitted from a laser scanner along the axial direction of the photosensitive drum onto the surface of the photosensitive drum. While scanning the laser beam in the main scanning direction, the photosensitive drum is rotated, and the laser beam is sequentially scanned in the sub-scanning direction, perpendicular to the main scanning direction, to form an image. If the laser scanner vibrates in the sub-scanning direction, the position of the laser beam irradiated on the surface of the photosensitive drum also shifts in the sub-scanning direction, resulting in the latent image being shifted (shifted) from its original position in the sub-scanning direction. Because the shift in the sub-scanning direction manifests itself in the image as blurring or banding, a scanner unit that is less susceptible to vibration in the sub-scanning direction is required. To address this issue, a configuration has been proposed in which a hollow elastic member and a leaf spring are used at the connection between the main frame and the scanner unit to prevent vibrations generated in the main frame from being transmitted to the scanner unit (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-003329 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional image forming devices require many parts, such as elastic members and leaf springs, which makes the device structure complicated and increases costs. For this reason, there is a need to reduce the number of parts and costs while increasing rigidity against vibrations.

[0005] The present invention has been made under these circumstances, and has as its object to increase the vibration rigidity of a scanner unit with a simple configuration. [Means for solving the problem]

[0006] (1) a photosensitive body; an exposure device that irradiates a surface of the photosensitive body with laser light so that an electrostatic latent image is formed on the photosensitive body; a light source that irradiates the laser light; and an optical deflector that deflects the laser light irradiated by the light source; a lens through which light deflected by the optical deflector passes; The light source The aforementioned Optical deflector and The lens a housing that houses the above-mentioned components, the housing having a first abutment surface and a second abutment surface; and a frame that supports the housing, the frame having: a first support portion that has a first support surface that abuts against the first abutment surface and supports the first abutment surface; and a second support portion that has a second support surface that abuts against the second abutment surface and supports the second abutment surface, the first abutment surface and the second abutment surface are provided on a bottom surface that constitutes an outer surface of the housing, both the first abutment surface and the first support surface are higher than both the second abutment surface and the second support surface, the first abutment surface and the first support surface are approximately parallel, and the second abutment surface and the second support surface are approximately parallel, When viewed in the direction of the rotation axis of the photosensitive member, The first contact surface, the second contact surface, the first support surface, and the second support surface each extend in a direction intersecting an irradiation direction of the laser light from the housing to the photosensitive member. and the photosensitive member is located on an extension of an optical path connecting the optical deflector and the lens. An image forming apparatus characterized by: (2) A photosensitive body, an exposure device that irradiates a surface of the photosensitive body with laser light so that an electrostatic latent image is formed on the photosensitive body, a light source that irradiates the laser light, an optical deflector that deflects the laser light irradiated by the light source, a housing that houses the light source and the optical deflector, the housing having a first abutment surface and a second abutment surface, and a frame that supports the housing, the frame having a first support part that has a first support surface that abuts on the first abutment surface and supports the first abutment surface, and a second support part that abuts on the second abutment surface and supports the second abutment surface, an image forming apparatus, characterized in that: the first abutment surface and the first support surface are provided on a bottom surface constituting an outer surface of a housing; both the first abutment surface and the first support surface are higher than both the second abutment surface and the second support surface; the first abutment surface and the first support surface are approximately parallel; and the second abutment surface and the second support surface are approximately parallel; when viewed in the direction of the rotation axis of the photosensitive body, the first abutment surface, the second abutment surface, the first support surface, and the second support surface each extend in a direction intersecting an irradiation direction of the laser light from the housing to the photosensitive body; and in the direction in which the laser light travels from the housing to the photosensitive body, the first abutment surface is located downstream of the second abutment surface. (3) A photosensitive body, an exposure device that irradiates a laser beam onto a surface of the photosensitive body so as to form an electrostatic latent image on the photosensitive body, a light source that irradiates the laser beam, an optical deflector that deflects the laser beam irradiated by the light source, a housing that houses the light source and the optical deflector, the housing having a first abutment surface and a second abutment surface, and a frame that supports the housing, the frame having: a first support portion that has a first support surface that abuts against the first abutment surface and supports the first abutment surface, and a second support portion that has a second support surface that abuts against the second abutment surface and supports the second abutment surface, the first abutment surface and the second abutment surface are provided on a bottom surface that constitutes an outer surface of the housing, both the first abutment surface and the first support surface are located above both the second abutment surface and the second support surface, and the first abutment surface and the first support surface are approximately parallel to each other. the second abutment surface and the second support surface are approximately parallel to each other, and when viewed in a direction of a rotation axis of the photosensitive member, the first abutment surface, the second abutment surface, the first support surface, and the second support surface each extend in a direction intersecting an irradiation direction of the laser light from the housing toward the photosensitive member, and the image forming apparatus comprises: a cartridge including the photosensitive member; a first cartridge support part to which one end side of the cartridge in the axial direction of the photosensitive member is attached; and a second cartridge support part to which another end side of the cartridge that is opposite to the one end side in the axial direction is attached, the first cartridge support part being attached to one end side of the frame in the axial direction, and the second cartridge support part being attached to the other end side of the frame opposite to the one end side in the axial direction. [Effects of the Invention]

[0007] According to the present invention, it is possible to increase the vibration rigidity of the scanner unit with a simple configuration. [Brief explanation of the drawings]

[0008] [Figure 1] Cross-sectional view of the image forming apparatus according to the first and second embodiments [Figure 2] Cross-sectional view of peripheral parts of the laser scanner of Example 1 [Figure 3]1 is an exploded perspective view of peripheral parts of a laser scanner according to a first embodiment; [Figure 4] 1 is a front perspective view of a laser scanner mounting portion according to a first embodiment of the present invention; [Figure 5] 1 is a rear perspective view of a laser scanner mounting portion according to a first embodiment of the present invention; [Figure 6] Enlarged view of peripheral parts of the laser scanner in Example 1 [Figure 7] Enlarged view of the scanner frame fastening portion of Example 1 [Figure 8] 1A and 1B are a right perspective view and a left perspective view showing the attachment of a laser scanner to a side plate according to a first embodiment of the present invention; [Figure 9] FIG. 1 is a perspective view of a laser scanner according to a modified example of the first embodiment; [Figure 10] 1 is a cross-sectional view of a laser scanner peripheral component according to a modified example of the first embodiment; [Figure 11] FIG. 10 is an exploded perspective view of peripheral parts of a laser scanner according to a modified example of the first embodiment. [Figure 12] FIG. 10 is an exploded perspective view of peripheral parts of a laser scanner according to a second embodiment. [Figure 13] 10 is a rear perspective view of the laser scanner mounting portion of the second embodiment. [Figure 14] FIG. 10 is an external perspective view showing an exterior cover and a main frame of another modified example. [Figure 15] FIG. 10 is a left side cross-sectional view showing the positional relationship between the exterior cover and the main frame of another modified example. [Figure 16] FIG. 10 is a diagram illustrating the positional relationship between the exterior cover and the main frame of another modified example. [Figure 17] FIG. 10 is an external perspective view showing an exterior cover and a main frame of another modified example. [Figure 18] FIG. 10 is a diagram illustrating the positional relationship between the exterior cover and the main frame of another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail by way of examples with reference to the accompanying drawings. [Example]

[0010] [Overall configuration of image forming device] An overview of the overall configuration of an image forming apparatus will be described using Figure 1. Here, image forming apparatuses include, for example, electrophotographic copiers, electrophotographic printers (LED printers, laser beam printers, etc.), electrophotographic facsimile machines, and electrophotographic word processors. Image forming apparatuses also include monochromatic or full-color image forming apparatuses used as output devices such as multifunction peripherals and workstations that also have the function of forming an image on a recording material. Figure 1 is a cross-sectional view showing the schematic configuration of a laser beam printer (hereinafter referred to as printer) 1, which is an example of an image forming apparatus. The recording material is the material on which an image is formed by the electrophotographic image forming apparatus, and includes, for example, paper, overhead projector sheets, etc.

[0011] The printer 1 is equipped with a recording material supply section 10 that supplies a recording material S, an image forming section 20 that forms an image on the supplied recording material S, an image fixing section 30 that fixes the formed image on the recording material S, and a recording material discharge section 40 that discharges the recording material S with the image fixed thereon to the outside of the machine. The recording material supply section 10 is located at the bottom of the printer 1 and is configured to store the recording material S. The recording material supply section 10 mainly comprises a paper feed roller 12, a transport roller 13, a separation roller 14, and a pair of registration rollers (hereinafter referred to as registration rollers) 15, and supplies the stored recording material S to the image forming section 20.

[0012] The image forming unit 20 has a cartridge equipped with a photosensitive drum 22 and a developing sleeve 23 as a photosensitive member, a laser scanner 21 as an exposure device, and a transfer roller 24, and forms an image on the recording material S. The laser scanner 21 has a light source and irradiates the surface of the photosensitive drum 22 with laser light. The transfer roller 24 faces the photosensitive drum 22 and transfers a toner image onto the recording material S. The image fixing unit 30 heats and fixes the unfixed toner image by having the recording material S pass through a nip portion consisting of a fixing pressure roller 31 and a fixing heating roller 34 equipped with a fixing heater (not shown) inside. In the recording material discharge unit 40, the heated and fixed recording material S is discharged to the outside of the printer 1 by the conveying force of the discharge roller pair 41 and is stacked above the discharge tray 47 and discharge extension tray 48. Here, the left side in FIG. 1 where the paper feed tray 11 and the output extension tray 48 are provided will be referred to as the "front side (FRONT)," and the right side in FIG. 1 where the duplex conveying path is provided will be referred to as the "rear side (REAR)." Also, the upper side in FIG. 1 where the output extension tray 48 is provided will be referred to as the "upper side (UP)," and the lower side in FIG. 1 where the paper feed tray 11 is provided will be referred to as the "lower side (DOWN)." Furthermore, the left side when facing the front of the printer 1 will be referred to as the "left side (LEFT)," and the right side will be referred to as the "right side (RIGHT)" (see FIG. 3, etc.).

[0013] [Explanation of the operation of the image forming device] The image forming operation of the printer 1 configured as described above will now be described. First, a laser scanner 21 irradiates a laser beam onto the photosensitive drum 22 based on an image signal from a control unit (not shown) provided in the printer 1 that has received a print command. The photosensitive drum 22 rotates counterclockwise, is cleaned by a cleaning device (not shown), and the laser beam is irradiated onto the uniformly charged surface. The electrostatic latent image formed on the photosensitive drum 22 by the irradiation of the laser beam is developed with toner on the developing sleeve 23, and a toner image is formed on the surface of the photosensitive drum 22.

[0014] Meanwhile, the paper feed roller 12 begins to rotate counterclockwise at a predetermined timing. Thereafter, when a command to start paper feeding is received from the control unit, the paper feed arm 16 descends counterclockwise around the transport roller 13. The paper feed roller 12 comes into contact with the uppermost sheet of recording material S stored in the paper feed tray 11 and transports the recording material S to the transport roller 13 by friction. After the recording material S has been transported to the transport roller 13, the paper feed arm 16 rises clockwise in the opposite direction to before, and the paper feed roller 12 moves away from the recording material S. If multiple sheets of recording material S are sent to the transport roller 13 at the same time, only the uppermost sheet is separated by the action of the separation roller 14 and transported to the pair of registration rollers 15 downstream.

[0015] The recording material S sent from the conveying roller 13 to the pair of registration rollers 15 is conveyed to the image forming unit 20, which includes a photosensitive drum 22 and a transfer roller 24. In the image forming unit 20, the toner image formed on the surface of the photosensitive drum 22 is transferred onto the surface of the recording material S as described above. Thereafter, the recording material S, onto which the unfixed toner image has been transferred, is conveyed to the image fixing unit 30. In the image fixing unit 30, the recording material S passes through a fixing nip formed by a fixing pressure roller 31, which rotates clockwise, and a fixing heat roller 34, which is driven to rotate counterclockwise by the fixing pressure roller 31. The fixing heat roller 34 has a fixing heater inside, and applies pressure to the recording material S at the fixing nip, while heating it with the fixing heater to fix the unfixed toner image on the recording material S.

[0016] Finally, the recording material S is discharged outside the printer 1 by a discharge roller pair 41, which is provided in the recording material discharge section 40 and forms a nip with a discharge drive roller 42 that rotates clockwise and a discharge driven roller 43 that is driven to rotate by the discharge drive roller 42. The discharged recording material S is placed, for example, with the image transfer surface facing downwards on a discharge tray 47 and a discharge extension tray 48. The discharge tray 47 is disposed below the nip of the discharge roller pair 41, and subsequent sheets are sequentially stacked on top of the discharged recording material S.

[0017] When printing on both sides of recording material S, the rotation direction of discharge drive roller 42 is reversed counterclockwise after the trailing edge of recording material S, on which image formation on the first side has been completed, passes the downstream end in the conveying direction of fixing guide 33, which is provided between the fixing nip portion and discharge roller pair 41. Then, recording material S enters a double-sided conveying path consisting of double-sided upper guide 44 and double-sided lower guide 45, and is conveyed to double-sided roller pair 46. When recording material S is no longer in the nip portion of discharge roller pair 41, discharge drive roller 42 begins to rotate clockwise again, preparing for the discharge of the second side of recording material S. Recording material S is conveyed by double-sided roller pair 46 to the nip portion formed by registration roller pair 15, and thereafter, image formation on the second side is performed through the same process as for the first side of recording material S.

[0018] [Frame composition] The frame configuration of the printer 1 will be described using Figure 8. Figure 8(a) is a perspective view of the right side plate 73, the left side plate 74, and the scanner frame 51 as viewed from the right side. Figure 8(b) is a perspective view of the right side plate 73, the left side plate 74, and the scanner frame 51 as viewed from the left side. The frame configuration of the printer 1 is such that the right side plate 73 is provided on the right side of the scanner frame 51 to which the scanner frame 51 is fixed, and the left side plate 74 is provided on the left side. The right side plate 73 and the left side plate 74 are side plates for attaching the image forming unit 20 and the image fixing unit 30 described in Figure 1. The right side plate 73 and the left side plate 74 are provided with attachment portions for each member such as the photosensitive drum 22, and are configured to be fixed to the laser scanner 21 so that each member such as the photosensitive drum 22 is positioned relative to the laser scanner 21.

[0019] [Support structure of laser scanner 21] (Main frame and subframe) The support structure of the laser scanner 21 of the first embodiment will be described with reference to Figs. 2 to 5. Fig. 2 is a cross-sectional view showing peripheral components of the laser scanner 21 of the first embodiment. In a cross section perpendicular to the longitudinal direction (left-right direction), the scanner frame 51 has a main frame 52, which is a first frame that forms two sides of a triangle, and a sub-frame 53, which is a second frame that forms one side of the triangle. The main frame 52 and the sub-frame 53 are fastened at multiple points in the longitudinal direction (left-right direction). The fastening at multiple points will be described later.

[0020] As shown in Fig. 2, the scanner frame 51 is made up of a main frame 52 and a sub-frame 53 fastened together. This forms a cylinder whose cross section perpendicular to the longitudinal direction has a triangular shape, forming a space Sp for accommodating at least a portion of the laser scanner 21 inside. One end of the laser scanner 21 is supported by a scanner stay 50 (supporting portion) provided in the space Sp inside the cylinder formed by the main frame 52 and the sub-frame 53, and the other end is supported from below by the main frame 52. The support structure for the laser scanner 21 will be described in detail later.

[0021] (Scanner Stay) FIG. 3 is an exploded perspective view of peripheral components of the laser scanner 21 of the first embodiment. FIG. 6 is a perspective view of the scanner frame 51 constructed by placing the laser scanner 21 on a main frame 52 supporting a scanner stay 50 and securing it with a spring (described later), and fastening a subframe 53 to the main frame 52. The scanner stay 50 is provided in the space Sp (FIGS. 2 and 6) (inside the space) of the scanner frame 51 and supports the laser scanner 21. As shown in FIGS. 2 and 3, the cross-sectional shape of the scanner stay 50 (hereinafter referred to as the cross-sectional shape) (the shape of the cross section perpendicular to the left-right direction) is approximately Z-shaped. The scanner stay 50 extends in the left-right direction; that is, it is installed so that its longitudinal direction is aligned with the rotational axis direction of the photosensitive drum 22 and the left-right direction of the printer 1, and has a shape that is resistant to vibration and static deformation. The scanner stay 50 includes a fixed portion 50A fixed to the main frame 52, a connecting portion 50B having one end connected to the fixed portion 50A and the other end extending away from the fixed portion 50A, and a scanner positioning portion 50C connected to the other end of the connecting portion 50B. In the first embodiment, the cross-sectional shape of the scanner stay 50, which is perpendicular to the longitudinal direction and is composed of the fixed portion 50A, the connecting portion 50B, and the scanner positioning portion 50C, is substantially Z-shaped. Furthermore, the angle between the fixed portion 50A and the connecting portion 50B and the angle between the connecting portion 50B and the scanner positioning portion 50C are each approximately 90° as shown in FIG. 2 , but are not limited thereto and may be different angles or angles other than approximately 90°. Furthermore, the cross-sectional shape of the scanner stay 50, which is composed of the fixed portion 50A, the connecting portion 50B, and the scanner positioning portion 50C, which is perpendicular to the longitudinal direction, may be a U-shape or other shape.

[0022] (Laser scanner installation) In a cross section perpendicular to the longitudinal direction, the main frame 52 has a first surface 52A, which is a first surface that forms one of the two sides of a triangle, and a second surface 52B, which is a second surface that forms the other side (FIGS. 2 and 3). The main frame 52 has a substantially L-shaped cross section, with the first surface 52A functioning as a support that supports the laser scanner 21 in the vertical direction, and the second surface 52B, which is substantially perpendicular to the first surface 52A, supporting the scanner stay 50. The sub-frame 53 has an opening 53A through which the laser light emitted from the laser scanner 21 passes so as not to be obstructed. The sub-frame 53 forms one side of the triangle. That is, the main frame 52 has a first surface 52A extending in the up-down and left-right directions and a second surface 52B extending in the left-right and front-rear directions, and one end and the other end of the sub-frame 53 are fixed to the orthogonal first surface 52A and second surface 52B of the main frame 52. In this way, the space Sp having a triangular cross section described above is formed by the three surfaces: the first surface 52A of the main frame 52, the second surface 52B of the main frame 52, and the sub-frame 53.

[0023] FIG. 4 is an enlarged front view of the mounting portion of the laser scanner 21 according to the first embodiment. As shown in FIG. 4, an opening 52C is formed in the first surface 52A of the main frame 52. The opening 52C has an edge 52A1, which is the lower end extending in the left-right direction, an edge 52A2, which is the upper end extending in the left-right direction, an edge 52A3, which is one end extending in the left-right direction, and an edge 52A4, which is the other end extending in the left-right direction. As indicated by arrow A in FIG. 3, the laser scanner 21 is inserted from the front side through the opening 52C into the space Sp and installed on the scanner stay 50. At this time, the scanner positioning portion 50C of the scanner stay 50 has at least two through-holes, and two bosses 21C protruding downward and facing the laser scanner 21 are respectively inserted through these through-holes as shown in FIG. 2. This allows the laser scanner 21 to be positioned in the front-rear and left-right directions while allowing it to move up and down relative to the scanner positioning portion 50C.

[0024] Furthermore, a frame-side abutment portion 54, which is a first abutment portion, is provided on an edge portion 52A1 of the first surface 52A of the main frame 52. That is, the frame-side abutment portion 54 is provided on the rear end side in the direction in which the laser scanner 21 is inserted into the opening 52C. Meanwhile, the laser scanner 21 is provided with a first abutment portion 21A, which is a first abutted portion, on the front side, which is one end in the front-rear direction. In the first embodiment, the frame-side abutment portion 54 of the first surface 52A of the main frame 52 is configured to abut against the first abutment portion 21A of the laser scanner 21. More specifically, an upper portion of the frame-side abutment portion 54 abuts against a lower portion of the first abutment portion 21A. This allows the laser scanner 21 to be positioned in the up-down direction at the front end portion. Although the frame-side contact portion 54 and the first contact portion 21A are provided at two locations in FIGS. 3 and 4, they may be provided at one location or at three or more locations.

[0025] FIG. 5 is an enlarged rear view of the mounting portion of the laser scanner 21 of the first embodiment. As shown in FIG. 5, the laser scanner 21 has a second abutting portion 21B, which is a second abutted portion, on the rear side, which is the other end in the front-rear direction. In other words, the laser scanner 21 has the second abutting portion 21B on the tip side in the direction of insertion into the opening 52C. Meanwhile, the scanner stay 50 has a stay-side abutting portion 55, which is a second abutting portion, at a predetermined position in the longitudinal direction (left-right direction) so as to abut against the second abutting portion 21B of the laser scanner 21. The stay-side abutting portion 55 is formed so as to partially protrude in the extension direction of the connecting portion 50B from the other end opposite to the one end connected to the fixing portion 50A of the connecting portion 50B of the scanner stay 50, without being bent from the connecting portion 50B to form the scanner positioning portion 50C. When the laser scanner 21 is inserted into the space Sp, the second contact portion 21B of the laser scanner 21 comes into contact with the stay-side contact portion 55 of the scanner stay 50, thereby positioning the laser scanner 21 in the up-down direction at the rear end portion. More specifically, the upper portion (end portion) of the stay-side contact portion 55 comes into contact with the lower portion of the second contact portion 21B. Although the stay-side contact portion 55 and the second contact portion 21B are provided in one location in FIGS. 3, 5, etc., they may be provided in two or more locations. As described above, the frame-side contact portion 54 is formed on the first surface 52A of the main frame 52, and the stay-side contact portion 55 is formed at an open end (edge) on the scanner stay 50, and each comes into contact with the first contact portion 21A and the second contact portion 21B of the laser scanner 21 approximately perpendicularly.

[0026] (Laser scanner fixing) As shown in FIG. 4, the first contact portion 21A fixes the laser scanner 21 by biasing the laser scanner 21 downward using the restoring force of elastic deformation of a frame-side spring 56, which serves as a fixing means. A hole 54D and a spring retainer 54E are provided near the frame-side contact portion 54 on the first surface 52A of the main frame 52. A spring receiving portion 21A1 for hooking the frame-side spring 56 is provided on the first contact portion 21A of the laser scanner 21. The frame-side spring 56 is a wire spring having an engaging portion (hooking portion 56A) with the spring receiving portion 21A1 between an engaging portion with the hole 54D and an engaging portion with the spring retainer 54E, as shown in FIG. 4, for example. Specifically, one end of the frame-side spring 56 penetrates the hole 54D from the front side to the rear side, and the other end is hooked from the bottom side to the spring retainer 54E. A hook portion 56A is provided at the middle portion of the frame-side spring 56 so as to be hooked onto the spring receiving portion 21A1 of the first contact portion 21A. The frame-side spring 56 biases the spring receiving portion 21A1 of the laser scanner 21, and therefore the first contact portion 21A, from above toward the frame-side contact portion 54, restricting vertical movement of the laser scanner 21. For example, the worker inserts one end of the frame-side spring 56 into the hole 54D and hooks the hook portion 56A from above the spring receiving portion 21A1 of the laser scanner 21. The worker then pushes the frame-side spring 56 downward and hooks the other end of the frame-side spring 56 onto the spring retainer 54E from below, thereby fixing the laser scanner 21 to the first surface 52A of the main frame 52.

[0027] The second contact portion 21B also urges the laser scanner 21 downward by the restoring force of the elastic deformation of the stay-side spring 57, which serves as a fixing means, thereby fixing the laser scanner 21. As shown in FIG. 5, a hole 55A and a spring retaining portion 55B are provided near the stay-side contact portion 55 of the scanner stay 50. A spring receiving portion 21B1 for hooking the stay-side spring 57 is provided on the second contact portion 21B of the laser scanner 21. The stay-side spring 57 is a wire spring in which an engaging portion (hooking portion 57A) for engaging with the spring receiving portion 21B1 is provided between an engaging portion with the hole 55A and an engaging portion with the spring retaining portion 55B, as shown in FIG. 5, for example. Specifically, one end of the stay-side spring 57 penetrates the hole 55A from the rear side to the front side, and the other end is hooked on the spring retaining portion 55B from the bottom side to the top side. A hook portion 57A is provided at the middle portion of the stay-side spring 57 so as to be hooked onto the spring receiving portion 21B1 of the second abutment portion 21B. The stay-side spring 57 biases the spring receiving portion 21B1 of the laser scanner 21, and therefore the second abutment portion 21B, from above toward the stay-side abutment portion 55, restricting vertical movement of the laser scanner 21. For example, the worker inserts one end of the stay-side spring 57 into the hole 55A and hooks the hook portion 57A from above the spring receiving portion 21B1 of the laser scanner 21. The worker then pushes the stay-side spring 57 downward and hooks the other end of the stay-side spring 57 onto the spring fastening portion 55B from below, thereby fixing the laser scanner 21 to the scanner stay 50.

[0028] The shapes of the frame-side spring 56 and the stay-side spring 57 are not limited to the modes shown in Figures 4 and 5. Therefore, the methods of engagement between the frame-side spring 56 and the main frame 52, and between the frame-side spring 56 and the laser scanner 21, etc. are not limited to the mode shown in Figure 4. Furthermore, the methods of engagement between the stay-side spring 57 and the scanner stay 50, and between the stay-side spring 57 and the laser scanner 21, etc. are not limited to the mode shown in Figure 5. The fixing means may also be, for example, screws instead of springs.

[0029] [Scanner Frame 51] The configuration of scanner frame 51 according to the first embodiment will be described below with reference to Fig. 3 etc. Scanner frame 51 according to the first embodiment has main frame 52, which is a first frame, and sub-frame 53, which is a second frame, as well as a right frame 70 provided on the right side of main frame 52 and sub-frame 53, and a left frame 71 provided on the left side. In other words, scanner frame 51 has a shape that extends left and right so that main frame 52 and sub-frame 53 connect right frame 70 and left frame 71, which are arranged on the left and right sides of the printer 1 main body.

[0030] As will be described later, the main frame 52 and the sub-frame 53 are connected by crimping at multiple locations. At the left and right ends of the scanner frame 51, a right frame 70 and a left frame 71 are fastened to one end and the other end of the main frame 52 and the sub-frame 53 with fastening screws 75 (FIG. 8), respectively. In this way, the scanner frame 51 is box-shaped, and a space Sp is formed between the right frame 70 and the left frame 71. In the first embodiment, the right frame 70 and the left frame 71 are fixed to the first surface 52A, the second surface 52B, and the sub-frame 53 of the main frame 52, respectively. However, the right frame 70 and the left frame 71 may be fixed to at least two of the first surface 52A, the second surface 52B, and the sub-frame 53 of the main frame 52, respectively.

[0031] 3, the scanner stay 50 extends laterally to connect the right and left frames 70 and 71, which are arranged on the left and right sides of the printer 1 body. At the left and right ends of the scanner stay 50, screws 78 (FIG. 8) are fastened to stay fastening portions 72 (left side not shown) via through-holes provided in the right and left frames 70 and 71, respectively. In this manner, one longitudinal end of the scanner stay 50 is fixed to the right frame 70, and the other longitudinal end is fixed to the left frame 71. In particular, the screws 78 are provided in the portions of the right and left frames 70 and 71 that overlap with the triangular end face regions formed by the main frame 52 and the sub-frame 53 in the longitudinal direction.

[0032] The cross-sectional shape of the scanner stay 50 is not limited to that of the first embodiment, and may be, for example, a square or an L-shape with increased plate thickness. The scanner stay 50 of the first embodiment may be made of a bent metal plate or a rod-shaped material, for example, made of resin, as long as the rigidity is ensured and the scanner stay 50 itself is not easily bent. Furthermore, the scanner stay 50 may be configured to fix the laser scanner 21 and to be fixed to the right frame 70 and the left frame 71, and may not have the fixing portion 50A or the connecting portion 50B.

[0033] (crimped part) 7, which shows an enlarged view of a portion of scanner frame 51, the configuration for integrating main frame 52 and sub-frame 53 by crimping will be described in detail. Scanner frame 51 has a plurality of crimping portions 58, and these crimping portions 58 connect sub-frame 53, which is the component to be fastened, to main frame 52, which is the component to be fastened.

[0034] The subframe 53 has a plurality of fastening holes 58A arranged at predetermined intervals in the longitudinal direction (left-right direction) at one connection portion that is connected adjacent to the first surface 52A of the main frame 52 and at the other connection portion that is connected to the second surface 52B of the main frame 52.

[0035] Meanwhile, one connection portion of the main frame 52 has a crimping shaft 58B at a portion connected to one end of the subframe 53 and at a position corresponding to the fastening hole 58A of the subframe 53. Similarly, a connection portion of the second surface 52B of the main frame 52 also has a crimping shaft 58B (not shown in FIG. 7) at a portion connected to the other end of the subframe 53 and at a position corresponding to the fastening hole 58A of the subframe 53. The crimping shaft 58B has a cylindrical shape that protrudes from one connection portion adjacent to the first surface 52A of the main frame 52 and from the connection portion of the second surface 52B so as to form a flange on the edge of the through hole by burring or the like.

[0036] The crimped portion 58 is arranged so that the crimped shaft 58B of the main frame 52 passes through the fastening hole 58A of the subframe 53. In this way, one end and the other end of the subframe 53 are arranged to overlap the connection portion connected to the first surface 52A of the main frame 52 so as to be adjacent to each other, and the connection portion connected to the second surface 52B of the main frame 52. The crimped shaft 58B is crimped and plastically deformed, so that the subframe 53 is sandwiched between the deformed portion of the crimped shaft 58B and the connection portion connected to the first surface 52A of the main frame 52 so as to be adjacent to each other, and the connection portion connected to the second surface 52B of the main frame 52. As a result, the subframe 53 is fixed to the connection portion connected to the first surface 52A of the main frame 52 so as to be adjacent to each other, and the connection portion connected to the second surface 52B of the main frame 52, respectively, at the crimped portion 58. That is, the crimping portion 58 is constituted by a fastening hole 58A and a crimping shaft 58B, and is provided at a connection portion that is adjacent to and connected to the first surface 52A of the main frame 52, and at a connection portion of the second surface 52B.

[0037] All of the crimped portions 58 have substantially the same shape as in Fig. 7. In the first embodiment, the main frame 52 and the sub-frame 53 are fastened together by burring crimping, but the fastening means is not limited to this and may be other crimping means, screw fastening, welding, or the like.

[0038] (effect) In the first embodiment, the scanner frame 51 is box-shaped, connecting the right frame 70 and the left frame 71, which are arranged on the left and right sides of the printer 1 body, with the main frame 52 and the sub-frame 53. In other words, the main frame 52 and the sub-frame 53 are configured so that the cross section perpendicular to the longitudinal direction forms a triangle. This configuration increases rigidity against torsional force around the longitudinal axis. Furthermore, the right frame 70 and the left frame 71 are provided at the longitudinal ends of the main frame 52 and the sub-frame 53. This configuration increases rigidity against torsional force around the longitudinal axis and also suppresses deformation of the first surface 52A and the second surface 52B of the main frame 52 and the sub-frame 53, which correspond to the sides of the triangle in the cross section perpendicular to the longitudinal direction, inward and outward bending of the space Sp. In the first embodiment, the scanner stay 50 is fixed to the right frame 70 and the left frame 71, respectively, and connects the right frame 70 and the left frame 71. With this configuration, even if deflection occurs in the second surface 52B of the main frame 52, displacement of the scanner stay 50, and therefore the laser scanner 21, can be suppressed. Furthermore, the screws 78 are provided in the portions of the right frame 70 and the left frame 71 that overlap with the triangular end face regions formed by the main frame 52 and the sub-frame 53 in the longitudinal direction. With this configuration, the scanner stay 50 can be provided in portions of the right frame 70 and the left frame 71 that are less likely to deform when an external force is applied, thereby better suppressing displacement of the scanner stay 50. By suppressing twisting of the scanner frame 51 and deflection of the members that make up the scanner frame 51 in this way, vibrations that displace the laser scanner 21 in the sub-scanning direction are suppressed, and the vibration rigidity of the scanner frame 51 can be increased.

[0039] In particular, in the first embodiment, at least the longitudinal ends of the main frame 52 and the sub-frame 53 are configured without any notches or holes, and the cross section perpendicular to the longitudinal direction surrounding the space Sp is configured as a continuous ring. That is, the right frame 70 and the left frame 71 are configured to be fixed to the end faces of a cylindrical body formed by the main frame 52 and the sub-frame 53, which forms a triangular ring. Specifically, when a cross section of the scanner frame 51 is taken at the longitudinal center, the first surface 52A of the main frame 52 has an opening 52C, and the sub-frame 53 has an opening 53A, so the cross section is not a triangular ring, but rather has broken triangle edges. However, at least one end and the other end of the scanner frame 51 do not have such openings, and the cross section is a triangular ring with continuous edges. This allows the right frame 70 and the left frame 71 to be firmly fixed to the main frame 52 and the sub-frame 53, respectively, increasing rigidity against sudden external forces and torsional deformation. Fixing the scanner stay 50 to this highly rigid scanner frame 51 suppresses vibration propagation to the laser scanner 21, thereby reducing image defects such as blurring and banding. The right frame 70 and the left frame 71 may be made of not only sheet metal but also resin, and may be integrated with the right and left plates 73 and 74. Furthermore, as long as the rigidity of the scanner frame 51 can be ensured, for example, the sub-frame 53 may be thinner than the main frame 52 or the main frame 52 and the sub-frame 53 may be integrated, thereby reducing material costs and the number of parts. The scanner frame 51 may also be constructed using three frames having crimping portions 58 at both ends, as described in FIG. 7 . In this case, two frames may be crimped at each of the three corners of the triangular cross section of the scanner frame 51.

[0040] In the first embodiment, the scanner stay 50 and the second surface 52B of the main frame 52 are in contact with each other, specifically, are fixed to each other. However, the scanner stay 50 does not necessarily have to be in contact with the second surface 52B of the main frame 52 as long as the stay fastening portions 72 (FIG. 3) at least at both longitudinal ends of the scanner stay 50 are fixed to the right frame 70 and the left frame 71. As a result, even if the second surface 52B of the main frame 52 is bent, the scanner stay 50 will not be affected.

[0041] As described above, according to the first embodiment, it is possible to increase the vibration rigidity of the scanner unit with a simple configuration. In this case, since it is possible to increase the rigidity only in areas where high vibration rigidity is required, it is possible to eliminate unnecessary increases in costs due to excessive rigidity. Furthermore, since it is possible to ensure torsional rigidity around the scanner unit, it is possible to realize a configuration that is more resistant to plastic deformation due to impacts during transportation, etc.

[0042] In the first embodiment, the frame of the printer 1 body is formed by attaching the right side plate 73 to the right frame 70 and the left side plate 74 to the left frame 71. In other words, the right side plate 73 and the left side plate 74 are attached with the photosensitive drum 22 and other components positioned relative to the laser scanner 21. Therefore, by configuring the scanner frame 51 of the scanner unit with increased rigidity, the positioning accuracy of the photosensitive drum 22 and other components relative to the laser scanner 21 can be improved.

[0043] [Modification of Example 1] The method for fixing the laser scanner 21 is not limited to the configuration described in Example 1. Therefore, the following describes a modified example of the support configuration for the laser scanner 21. In this modified example, the configuration of the laser scanner 21 that was not described in detail in Example 1 will be described first, and then the support configuration for the laser scanner 21 will be described.

[0044] [Laser scanner configuration] 9(a) is a top perspective view of the laser scanner 21, which is an optical scanning device, as viewed from above, and FIG. 9(b) is a bottom perspective view of the laser scanner 21 as viewed from the bottom. Note that FIG. 9(a) shows a state in which a cover covering an opening of the laser scanner 21 has been removed in order to explain the internal configuration. When the laser scanner 21 is installed in the printer 1, the opening of the laser scanner 21 is covered with an optical cover (not shown) made of resin or metal, and the inside of the laser scanner 21 is sealed.

[0045] An optical deflector 211 that deflects the laser light and various optical components are arranged inside a housing 203 of the laser scanner 21. The optical deflector 211 includes a rotary polygon mirror 213 that deflects the optical path of the incident laser light, a scanner motor 212 that rotates and drives the rotary polygon mirror 213, and a control IC that controls the rotation of the scanner motor 212. The optical deflector 211 that deflects the laser light L may use a resonance-type optical scanning element such as a so-called MEMS. The housing 203 of this modified example is made of resin. In the following, the direction in which the laser light L deflected and scanned by the optical deflector 211 scans the surface of the photosensitive drum 22 (which is also the direction of the rotation axis of the photosensitive drum 22) is referred to as the main scanning direction, and the direction perpendicular to the main scanning direction (which is also the rotation direction of the photosensitive drum 22) is referred to as the sub-scanning direction.

[0046] Laser light L emitted from a laser diode 201, which serves as a light source, in accordance with image information is converted by a composite anamorphic collimator lens 202 into substantially parallel or convergent light in the main scanning direction and into convergent light in the sub-scanning direction. The laser light L passing through the composite anamorphic collimator lens 202 is then limited to a predetermined beam diameter by an optical diaphragm 204 formed in a housing 203. The laser light L passing through the optical diaphragm 204 proceeds to a rotary polygon mirror 213 driven by a scanner motor 212, and is deflected by being reflected by the reflecting surfaces of the rotary polygon mirror 213. The deflected laser light L proceeds to an fθ lens 205, passes through the fθ lens 205, and is then focused onto a photosensitive drum 22 through an opening (emission port) provided in the housing 203 through which the laser light L passes, forming an electrostatic latent image on the photosensitive drum 22. 9(a), the broken line indicates the range in the main scanning direction in which the laser light L deflected by the rotary polygon mirror 213 is emitted.

[0047] Next, the two mounting bearing surfaces, the first contact portion 21A and the second contact portion 21B, will be described. Fig. 9(b) is a perspective view showing the bottom surface of the laser scanner 21. In the figure, the upper left side is the bottom surface on the front side of the housing 203 where an opening (emission port) through which laser light is emitted is provided, and the lower right side is the bottom surface on the front side of the housing 203 where the optical deflector 211 is installed. A total of three contact portions, two first contact portions 21A and one second contact portion 21B, are provided on the bottom surface of the laser scanner 21. The mounting reference surface is a bearing surface that abuts against the scanner stay 50 and the main frame 52 when the laser scanner 21 is supported by the scanner stay 50 and the main frame 52. In this modified example, the mounting reference surface has a square shape of approximately 5 mm x 5 mm and a smooth flat surface. In this modification, the second contact portion 21B is provided near the center of the end portion of the housing 203 of the laser scanner 21 on the side of the laser light L emission port. On the other hand, the two first contact portions 21A are provided at positions equidistant in the main scanning direction (longitudinal direction in the drawing) across a position facing the second contact portion 21B, near the end portion of the housing 203 on the side where the optical deflector 211 is installed, opposite the laser light emission port side of the laser scanner 21. In this modification, one mounting reference surface is provided on the bottom surface of the housing 203 on the side of the laser light L emission port and two on the side where the optical deflector 211 is installed, but two mounting reference surfaces may be provided on the side of the laser light L emission port and one on the side where the optical deflector 211 is installed.

[0048] As will be described later, the two first and second contact portions 21A and 21B have inclined surfaces that have the same angle with respect to the bottom surface of the housing 203 so that the housing 203 of the laser scanner 21 is inclined at the same angle with respect to the photosensitive drum 22 when the first and second contact portions 21A and 21B contact the scanner stay 50 and the main frame 52. Furthermore, two spring bearing portions 21A1 and 21B1 that protrude from the housing 203 are provided on the outer periphery of the housing 203 at positions facing the two first and second contact portions 21A and 21B in the longitudinal direction (also the main scanning direction) of the housing 203. As will be described later, the two spring bearing portions 21A1 and 21B1 are provided to bias the laser scanner 21 against the scanner stay 50 and the main frame 52 by a stay-side spring 57 and a frame-side spring 56 (see FIGS. 10 and 11). 9(b) is a boss hole for supporting the rotation shaft of the scanner motor 212 of the optical deflector 211.

[0049] [Configuration supporting laser scanner] Next, a method of supporting the laser scanner 21 by the scanner stay 50 and main frame 52 in this modified example will be described. Fig. 10 is a schematic cross-sectional view illustrating the configuration of the scanner stay 50 and main frame 52 that support the laser scanner 21 in the printer 1, and shows a cross-sectional view taken at the center of the rotation axis of the scanner motor 212 of the optical deflector 211 of the laser scanner 21. Note that Fig. 10 does not show the main frame 52 that is positioned higher than the laser scanner 21. In Fig. 10, the X-axis indicates the horizontal direction, and the Y-axis indicates the vertical direction.

[0050] FIG. 10 is a cross-sectional view showing how the laser scanner 21 is supported by the scanner stay 50 and the main frame 52. Specifically, in FIG. 10, the second abutment portion 21B provided on the bottom surface of the housing 203 of the laser scanner 21 abuts against the stay-side abutment portion 55 of the scanner stay 50, and the two first abutment portions 21A abut against the corresponding frame-side abutment portions 54 of the main frame 52, thereby supporting the laser scanner 21 on the scanner stay 50 and the main frame 52. The stay-side abutment portion 55 refers to the abutment surface of the end abutting against the second abutment portion 21B of the scanner stay 50. Similarly, the frame-side abutment portion 54 refers to the abutment surface of the end abutting against the two first abutment portions 21A of the main frame 52. One of the first abutment portions 21A is not shown in FIG. 10. The dashed line indicates the optical path of laser light L emitted from a laser diode 201 (not shown in Figure 10) and deflected by a rotating polygonal mirror 213 driven by a scanner motor 212 of an optical deflector 211, scanning the surface of the photosensitive drum 22.

[0051] In this modification, the position of the stay-side contact portion 55 of the scanner stay 50, with which the second contact portion 21B of the laser scanner 21 abuts, from the bottom surface inside the printer 1 is higher than the position of the frame-side contact portion 54 of the main frame 52, with which the first contact portion 21A abuts. Therefore, the laser scanner 21 is installed on the scanner stay 50 and the main frame 52 at an elevation angle θ from the horizontal direction (the X-axis direction in the drawing) with respect to the photosensitive drum 22. As shown in FIG. 10 , the angle θ is the angle with respect to the rotating polygon mirror 213 (or the bottom surface of the housing 203 of the laser scanner 21), which is perpendicular to the rotation axis of the scanner motor 212 of the optical deflector 211. The planes (reference planes) of the two first and second abutment portions 21A and 21B, which abut against the stay-side abutment portion 55 of the scanner stay 50 and the frame-side abutment portion 54 of the main frame 52, are also formed so as to form an angle θ with respect to the bottom surface of the housing 203 of the laser scanner 21. Furthermore, the positions of the frame-side abutment portion 54 and the stay-side abutment portion 55 are set so that the angle of the line segment connecting the frame-side abutment portion 54 of the main frame 52 and the stay-side abutment portion 55 of the scanner stay 50 with respect to the horizontal direction is angle θ. Therefore, the entire surfaces of the first and second abutment portions 21A and 21B are parallel to the frame-side abutment portion 54 of the main frame 52 and the stay-side abutment portion 55 of the scanner stay 50. As a result, when the first abutment portion 21A and the second abutment portion 21B abut against the frame-side abutment portion 54 of the main frame 52 and the stay-side abutment portion 55 of the scanner stay 50, the entire mounting reference surface abuts (is in surface contact). Note that, although one of the first abutment portions 21A is not shown in Fig. 10, it abuts against the frame-side abutment portion 54 (not shown) of the main frame 52 with a configuration similar to that of the first abutment portion 21A shown in Fig. 10.

[0052] Further, stay-side spring 57 is stretched across the upper side of spring receiving portion 21B1 provided on housing 203 of laser scanner 21 and the lower side of spring retainer 55B provided on scanner stay 50. Meanwhile, frame-side spring 56 is stretched across the upper side of spring receiving portion 21A1 provided on housing 203 of laser scanner 21 and the lower side of middle spring retainer 54E provided on main frame 52. By stay-side spring 57 and frame-side spring 56 arranged in this manner, laser scanner 21 is biased in the directions of scanner stay 50 and main frame 52.

[0053] [Main frame configuration] Here, we will explain the configuration of the scanner stay 50 and main frame 52 shown in Fig. 10 and the method of supporting the laser scanner 21 with a wire spring. Fig. 11(a) is a perspective view showing the main frame 52 and sub-frame 53, which are members that make up the scanner frame 51, as well as the scanner stay 50 attached to the scanner frame 51, disassembled into individual members.

[0054] The subframe 53 has four surfaces 53c, 53d, 53e, and 53f adjacent to surface 53b, with surface 53b at the center. Surface 53b has an opening 53A in the center to allow laser light emitted from the laser scanner 21 to pass through. Surfaces 53c and 53d on both sides of surface 53b in the left-right direction in the figure are provided for connection to side panel frames (not shown) provided on the sides of the printer 1, and the circular holes in the figure are screw holes for connection to the side panel frames. Surface 53e, adjacent to the upper side of surface 53b in the figure, has a screw hole for connection to surface 52C of the mainframe 52. Surface 53f adjacent to surface 53b has a screw hole (not shown) for fixing the subframe 53 to the bottom surface of the housing of the printer 1. Fixing surface 53f to the printer 1 fixes the scanner frame 51 to the printer 1 and increases the rigidity of the scanner frame 51.

[0055] The scanner stay 50 is formed by bending a single sheet metal into an L-shape. The scanner stay 50 has a fixed portion 50A (first surface) and a connecting portion 50B (second surface) bent perpendicularly or vertically to the fixed portion 50A. The fixed portion 50A has holes for connecting the scanner stay 50 to the main frame 52 with screws 103 (see FIG. 10). FIG. 10 shows the scanner stay 50 screwed to the main frame 52. Meanwhile, the connecting portion 50B has a stay-side abutment portion 55 (support seat surface) with which the second abutment portion 21B of the housing 203 of the laser scanner 21 abuts, and two spring retaining portions 55B protruding from the connecting portion 50B for biasing the spring receiving portion 21A1 of the housing 203 with a stay-side spring 57. The two spring retaining portions 55B are formed by cutting portions near the stay-side abutment portion 55 of the connecting portion 50B at equal distances from the spring receiving portion 21A1 of the housing 203, and bending the cut portions so that they are perpendicular to the connecting portion 50B.

[0056] The main frame 52 is formed by bending a single sheet metal into an L-shape and forming an opening. The main frame 52 has a first surface 52A (third surface), a second surface 52B (fourth surface) bent perpendicularly or vertically to the first surface 52A, and a surface 52C bent perpendicularly to the second surface 52B. As described above, the surface 52C is provided for connection to the surface 53e of the subframe 53, and is provided with screw holes for screwing to the surface 53e of the subframe 53. The first surface 52A is provided with screw holes for connecting to the scanner stay 50 and for fixing the main frame 52 to the bottom surface of the housing of the printer 1. The second surface 52B is provided with an opening that serves as an entrance and exit for the laser scanner 21 when attaching or detaching the laser scanner 21. The edge 52B1 of the opening is a flat surface (support seat surface) with which the two first contact portions 21A of the housing 203 of the laser scanner 21 come into contact.

[0057] Further, three spring retainers 54E protruding from the second surface 52B are provided near the edge 52B1 of the opening so that the frame-side spring 56 can bias the spring retainer 21A1 of the housing 203, the spring retainer 21B1. The three spring retainers 54E are formed by cutting portions of the second surface 52B near the edge 52B1 at equal distances from the spring retainer 21A1 of the housing 203, the spring retainer 21B1, and bending the cut portions so that they are perpendicular to the second surface 52B. The laser scanner 21 shown in FIG. 11(a) is a perspective view seen from the opposite side to the side where the opening from which the laser light L is emitted is provided, and it can be seen that the spring retainers 21A1 of the two first abutment portions 21A, which are biased by the frame-side spring 56, are provided on the end sides of the outer periphery of the housing 203.

[0058] [Scanning optical device biased by wire spring] FIG. 11(b) is a perspective view showing a state in which two first contact portions 21A of the housing 203 of the laser scanner 21 are installed on an edge portion 52B1 of the main frame 52. In FIG. 11(b), two spring bearing portions 21A1 provided on the housing 203 of the laser scanner 21 and three spring retaining portions 54E provided on the main frame 52 are biased by frame-side springs 56. Specifically, the frame-side springs 56 are installed as follows. That is, for the three spring retaining portions 54E provided on the main frame 52, the frame-side springs 56 are installed so as to contact the back surfaces of the respective claw portions (surfaces facing downward in the figure). On the other hand, for the two spring bearing portions 21A1 provided on the housing 203 of the laser scanner 21, the frame-side springs 56 are installed so as to contact the front surfaces of the respective claw portions (surfaces facing upward in the figure). Furthermore, the frame-side spring 56 is bent into a crank shape between the claws provided on the housing 203 of the laser scanner 21 and the claws provided on the main frame 52 in accordance with the height of each claw. Although not shown in FIG. 11(b), the spring bearing portion 21B1 provided on the housing 203 of the laser scanner 21 and the two spring retaining portions 55B provided on the scanner stay 50 are biased by the stay-side spring 57 in a manner similar to that described above. In order to make the laser scanner 21 detachable, the stay-side spring 57 and the frame-side spring 56 are installed so as to be detachable.

[0059] As described above, in this modification, the laser scanner 21 is supported by the stay-side contact portion 55 of the scanner stay 50 and the edge portion 52B1 of the main frame 52 via the two first and second contact portions 21A and 21B. Vibrations of the laser scanner 21 caused by the scanner motor 212 of the optical deflector 211 are unlikely to be transmitted in a direction perpendicular to the planes of the scanner stay 50 and the main frame 52. This reduces deflections of the connection portions 50B and 52B (see FIG. 11(a)) formed in the vertical direction (the Y-axis direction in FIG. 10) of the scanner stay 50 and the main frame 52. As a result, vibrations of the laser scanner 21 in the sub-scanning direction (the Y-axis direction in FIG. 10) can be reduced without adding a reinforcing member. Furthermore, degradation of image quality, such as pitch unevenness, caused by periodic shifts in the sub-scanning direction (the rotation direction of the photosensitive drum 22) of the irradiation position of the laser light L emitted from the laser scanner 21 on the photosensitive drum 22 can be suppressed.

[0060] 10, since the laser beam L from the laser scanner 21 is irradiated onto the photosensitive drum 22 from a diagonally downward direction, the position of the stay-side contact portion 55 of the scanner stay 50 in the vertical direction (Y-axis direction) is higher than the position of the edge portion 52B1 of the main frame 52 in the vertical direction. Therefore, the laser scanner 21 can be disposed tilted upward in the figure with respect to the horizontal direction (X-axis direction). Furthermore, the angle between the two first and second contact portions 21A and 21B and a direction perpendicular to the rotation shaft of the scanner motor 212 and the angle between the line segment connecting the stay-side contact portion 55 of the scanner stay 50 and the edge portion 52B1 of the main frame 52 and the horizontal direction (X-axis direction) are both the same angle θ. Therefore, when the laser scanner 21 is installed, the two first and second contact portions 21A and 21B are substantially parallel to the stay-side contact portion 55 and the edge portion 52A1, so that the two first and second contact portions 21A and 21B are in surface contact with the stay-side contact portion 55 and the edge portion 52B1, allowing the laser scanner 21 to be stably installed. In particular, in this modification, as shown in FIG. 11( a), the connection portion 50B of the scanner stay 50 is bent perpendicular to the fixing portion 50A. Similarly, the second surface 52B of the main frame 52 is bent perpendicular to the first surface 52A. As a result, the two first and second contact portions 21A and 21B provided on the housing 203 of the scanning optical device are in surface contact with the stay-side contact portion 55 of the scanner stay 50 and the edge portion 52B1 of the main frame 52 on a horizontal plane. Therefore, the connection portion 50B having the stay side abutment portion 55 of the scanner stay 50 and the second surface 52B having the edge portion 52B1 of the main frame 52 can bear the load of the laser scanner 21 in an approximately vertical direction, allowing the laser scanner 21 to be installed more stably.

[0061] Furthermore, the two first and second contact portions 21A and 21B provided on the housing 203 of the laser scanner 21 come into surface contact with the stay-side contact portion 55 of the scanner stay 50 and the edge portion 52B1 of the main frame 52. Therefore, the two first and second contact portions 21A and 21B do not come into contact with the corners of the stay-side contact portion 55 of the scanner stay 50 and the edge portion 52B1 of the main frame 52, thereby preventing the two first and second contact portions 21A and 21B from being scraped off due to contact with the stay-side contact portion 55 and the corners of the edge portion 52B1. This prevents scraps of the two first and second contact portions 21A and 21B from scattering inside the printer 1 and prevents a decrease in the support accuracy of the laser scanner 21 caused by scraping off the two first and second contact portions 21A and 21B.

[0062] Furthermore, in this modification, the laser scanner 21 itself is tilted to set an angle to the laser light L that is irradiated onto the photosensitive drum 22. This eliminates the need to install a separate member such as a folding mirror inside the laser scanner 21 in order to set the emission angle of the laser light L emitted from the laser scanner 21. As a result, it is possible to reduce the space required for arranging the folding mirror, etc., inside the laser scanner 21, thereby realizing a smaller and less expensive laser scanner 21.

[0063] Furthermore, in this modified example, the laser scanner 21 is installed at an angle so that the laser light L can be irradiated onto the photosensitive drum 22 from a diagonally downward direction. Therefore, the installation position of the laser scanner 21 can be arranged at a lower position than when the laser light L is irradiated onto the photosensitive drum 22 from a horizontal direction. This makes it possible to reduce the height of the printer 1 by the amount of the lower installation position of the laser scanner 21. Furthermore, by installing the laser scanner 21 at an angle, the horizontal length of the printer 1 can also be reduced, making the printer 1 even more compact.

[0064] As described above, the first and second contact portions 21A and 21B provided on the housing 203 of the scanning optical device are supported by the stay-side contact portion 55 of the scanner stay 50 and the edge portion 52B1 of the main frame 52. In this modification, both longitudinal (main scanning direction) ends of the scanner stay 50 and the main frame 52 are in contact with side plate frames (not shown) provided inside the printer 1. Therefore, even if the laser scanner 21 is made smaller and the longitudinal length of the housing 203 is shortened, the laser scanner 21 can be supported by the scanner stay 50, the stay-side contact portion 55 of the main frame 52, and the edge portion 52A1, eliminating the need for additional support members and preventing an increase in the cost of the printer 1. As a result, the laser scanner 21 can be positioned more flexibly within the printer 1, making it possible to provide a compact, low-cost printer 1.

[0065] As described above, according to this modification, the scanning optical device can be stably supported by the sheet metal frame. [Example]

[0066] FIG. 12 is an exploded view of peripheral components of the laser scanner 21 of Example 2. FIG. 13 is an enlarged view of the rear side of the mounting portion of the laser scanner 21 of Example 2. Example 2, which has a different support configuration for the laser scanner 21, will be described using FIGS. 12 and 13. The main change from Example 1 is that the scanner stay 50 is integrated with the main frame 52. In other words, the scanner stay 50 is formed by a part of the scanner frame 51. In the description of Example 2, only the changes from Example 1 will be mentioned, and the other configurations are the same as Example 1, so description thereof will be omitted.

[0067] In the second embodiment, the stay-side contact portion 55 and the stay fastening portion 72 are formed on the second surface 52B of the main frame 52. The second surface 52B of the main frame 52 also has a hole 55A and a spring retaining portion 55B. In the second embodiment, the number of parts can be further reduced, resulting in a simpler configuration. The shape of the portion corresponding to the scanner stay 50 is generally U-shaped, with an open bottom and a cross section perpendicular to the longitudinal direction. Furthermore, protrusions 77 that protrude outward are provided on both the left and right ends of the portion corresponding to the scanner stay 50 in the longitudinal direction. Meanwhile, openings 76 are provided on the right frame 70 and the left frame 71 at positions corresponding to the protrusions 77.

[0068] Specifically, the scanner stay 50 has a first protrusion 77R provided at one end in the longitudinal direction and a second protrusion 77L provided at the other end in the longitudinal direction. The right frame 70 has an opening 76R into which the protrusion 77R is inserted, and the left frame 71 has an opening 76L into which the protrusion 77L is inserted.

[0069] When fixing the right frame 70 and the left frame 71 to the scanner frame 51, the screws can be fastened in a positioned state by inserting the protrusions 77 on both the left and right ends into the openings 76 on the right frame 70 and the left frame 71. Positioning in this manner ensures the rigidity of the scanner frame 51.

[0070] Note that a configuration having a convex portion 77 may be applied to the configuration having the scanner stay 50 separate from the second surface 52B of the main frame 52 in the first embodiment. In this case, the right frame 70 and the left frame 71 in the first embodiment each have an opening 76 into which the convex portion 77 is inserted. This facilitates positioning of the scanner stay 50 with the right frame 70 and the left frame 71 in the first embodiment as well, making it possible to increase the rigidity of the scanner frame 51. Furthermore, in a configuration in which the separate scanner stay 50 does not contact the second surface 52B of the main frame 52, it becomes easy to position both ends of the scanner stay 50 with the right frame 70 and the left frame 71.

[0071] As described above, according to the second embodiment, the vibration stiffness of the scanner unit can be increased with a simple configuration.

[0072] <Other Examples> The above example is one embodiment of the image forming apparatus of the present invention, and the present invention is not limited to the above-mentioned form. For example, in the above-described embodiment, the scanner stay 50 is assumed to be made of a metal plate, but a resin material may also be used as long as it can satisfy the required rigidity. For example, in the above-described embodiment, the laser scanner 21 is fixed by being biased by a spring, but it may be fixed using other fixing means such as screws. For example, in the above-described embodiment, the cross-sectional shape of the scanner frame 51 is approximately triangular, but the cross-sectional shape may be circular, elliptical, or even other polygonal shapes as long as the cross-sectional shape does not impair the second moment of area. For example, in the above-described embodiment, a monochrome printer 1 having one photosensitive drum 22 has been described. However, the present invention is not limited to this, and can also be applied to a color image forming apparatus such as a tandem type having multiple photosensitive drums 22. The present invention can also be applied to an image forming apparatus that uses a transfer material carrying belt that carries and transports a transfer material. As described above, in the other embodiments as well, the vibration rigidity of the scanner unit can be increased with a simple configuration.

[0073] <Other variations> Alternatively, the movement of the laser scanner 21 may be restricted by the exterior cover of the printer 1. For example, the configuration according to this modified example may be such that a pressing portion is provided on the exterior cover of the image forming apparatus.

[0074] As shown in FIGS. 14 to 16, in this modified example, an exterior cover 101 that constitutes part of the exterior is provided with a retaining portion 102. The exterior cover 101 is fixed to a main frame 52 of the printer 1. Specifically, the position of the exterior cover 101 is restricted relative to the main frame 52 by having positioning portions 104a and 104b provided on the exterior cover 101 inserted into openings provided in the main frame 52. In this state, the exterior cover 101 is attached to the main frame 52 by engaging hooks 105a and 105b with the main frame 52. In this manner, it is desirable to position the retaining portion 102 above the center of gravity of the laser scanner 21.

[0075] With the above configuration, when the printer 1 vibrates as the printer 1 operates, the laser scanner 21 is prevented from moving too far away from the main frame 52. For example, when the laser scanner 21 receives a strong impact, such as when it is dropped due to logistics, the laser scanner 21 may float in a direction away from the main frame 52, relative to the direction of the force applied by the stay-side spring 57. However, as shown in FIG. 16 , by disposing the retaining portion 102 with a gap between it and the laser scanner 21, the elastic force of the stay-side spring 57 can be utilized to buffer a certain level of impact, and when the impact exceeds a certain level, the laser scanner 21 is supported by the retaining portion 102, thereby mitigating the applied impact. Note that the retaining portion 102 may be configured to be interposed between the laser scanner 21 and a separate component, and the laser scanner 21 may be supported by a separate component via the retaining portion 102. In addition, in order to prevent the laser scanner 21 from coming off the main frame 52 due to a strong impact such as being dropped during transportation, it is preferable that the gap be made smaller than the insertion amount of the boss 21C of the laser scanner 21 inserted into the through hole provided in the scanner positioning portion 50C of the scanner stay 50.

[0076] Furthermore, by providing the retaining portion 102 on the exterior cover 101, it is possible to prevent the laser scanner 21 from coming off the main frame 52 even when the opening of the main frame 52 cannot be narrowed. For example, this is also effective when there is a large gap between the laser scanner 21 and the opening of the main frame 52, such as when the laser scanner 21 has a convex portion on its upper surface.

[0077] Furthermore, widening the opening of the main frame 52 can improve assembly, and when maintenance of the laser scanner 21 is required, it can be easily removed by simply removing one of the exterior covers 101, which also improves service workability.

[0078] In this modified example, exterior cover 101 is configured to be constantly fixed to main frame 52. However, as shown in Figures 17 and 18, exterior cover 101 may be configured to be openable and closable around rotation fulcrum 106 and have retaining portion 102. Here, Figure 17 is an external perspective view showing the exterior cover and main frame of the modified example, and Figure 18 is a diagram explaining the positional relationship between the exterior cover and main frame of the modified example. In this way, appropriate modifications are possible within the scope of the present invention. [Explanation of symbols]

[0079] 21 Laser scanner 22 Photosensitive drum 50 Scanner Stay 51 Scanner Frame 70 Right Frame 71 Left Frame

Claims

1. A photoreceptor; an exposure device that irradiates a surface of the photosensitive member with laser light so that an electrostatic latent image is formed on the photosensitive member; a light source that irradiates laser light, an optical deflector that deflects the laser light irradiated by the light source, a lens through which the light deflected by the optical deflector passes, and a housing that houses the light source, the optical deflector, and the lens, the housing having a first contact surface and a second contact surface; a frame supporting the housing, the frame including: a first support portion having a first support surface that abuts against the first abutment surface and supports the first abutment surface; and a second support portion having a second support surface that abuts against the second abutment surface and supports the second abutment surface; Equipped with the first abutment surface and the second abutment surface are provided on a bottom surface that constitutes an outer surface of the housing, both the first abutment surface and the first support surface are above both the second abutment surface and the second support surface; the first abutment surface and the first support surface are substantially parallel to each other, the second abutment surface and the second support surface are substantially parallel to each other, When viewed in a rotational axis direction of the photosensitive member, the first contact surface, the second contact surface, the first support surface, and the second support surface each extend in a direction intersecting an irradiation direction of the laser light directed from the housing toward the photosensitive member, the photosensitive member is located on an extension of an optical path connecting the optical deflector and the lens; An image forming apparatus characterized by:

2. The first support portion and the second support portion are separate bodies.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. the first contact surface is located downstream of the second contact surface in a direction in which the laser light travels from the housing to the photosensitive member; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. The first abutment surface, the second abutment surface, the first support surface, and the second support surface extend in a substantially horizontal direction.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. a cartridge including the photoreceptor; a first cartridge support portion to which one end of the cartridge in the axial direction of the photosensitive member is attached, and a second cartridge support portion to which the other end of the cartridge, which is opposite to the one end in the axial direction, is attached, the first cartridge support portion is attached to one end side of the frame in the axial direction, the second cartridge support portion is attached to the other end side of the frame opposite to the one end side in the axial direction; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

6. A photoreceptor; an exposure device that irradiates a surface of the photosensitive member with laser light so that an electrostatic latent image is formed on the photosensitive member; a light source that irradiates a laser beam, an optical deflector that deflects the laser beam irradiated by the light source, and a housing that houses the light source and the optical deflector, the housing having a first contact surface and a second contact surface; a frame supporting the housing, the frame including: a first support portion having a first support surface that abuts against the first abutment surface and supports the first abutment surface; and a second support portion having a second support surface that abuts against the second abutment surface and supports the second abutment surface; Equipped with the first abutment surface and the second abutment surface are provided on a bottom surface that constitutes an outer surface of the housing, both the first abutment surface and the first support surface are above both the second abutment surface and the second support surface; the first abutment surface and the first support surface are substantially parallel to each other, the second abutment surface and the second support surface are substantially parallel to each other, When viewed in a rotational axis direction of the photosensitive member, the first contact surface, the second contact surface, the first support surface, and the second support surface each extend in a direction intersecting an irradiation direction of the laser light directed from the housing toward the photosensitive member, the first contact surface is located downstream of the second contact surface in a direction in which the laser light travels from the housing to the photosensitive member; An image forming apparatus characterized by:

7. The first support portion and the second support portion are separate bodies.

7. The image forming apparatus according to claim 6, wherein the image forming apparatus is a recording medium.

8. The first abutment surface, the second abutment surface, the first support surface, and the second support surface extend in a substantially horizontal direction.

7. The image forming apparatus according to claim 6, wherein the image forming apparatus is a recording medium.

9. A cartridge including the photosensitive member; a first cartridge support portion to which one end of the cartridge in the axial direction of the photosensitive member is attached, and a second cartridge support portion to which the other end of the cartridge, which is opposite to the one end in the axial direction, is attached, the first cartridge support portion is attached to one end side of the frame in the axial direction, the second cartridge support portion is attached to the other end side of the frame opposite to the one end side in the axial direction; 7. The image forming apparatus according to claim 6, wherein the image forming apparatus is a recording medium.

10. A photoreceptor; an exposure device that irradiates a surface of the photosensitive member with laser light so that an electrostatic latent image is formed on the photosensitive member; a light source that irradiates a laser beam, an optical deflector that deflects the laser beam irradiated by the light source, and a housing that houses the light source and the optical deflector, the housing having a first contact surface and a second contact surface; a frame supporting the housing, the frame including: a first support portion having a first support surface that abuts against the first abutment surface and supports the first abutment surface; and a second support portion having a second support surface that abuts against the second abutment surface and supports the second abutment surface; Equipped with the first abutment surface and the second abutment surface are provided on a bottom surface that constitutes an outer surface of the housing, both the first abutment surface and the first support surface are above both the second abutment surface and the second support surface; the first abutment surface and the first support surface are substantially parallel to each other, the second abutment surface and the second support surface are substantially parallel to each other, When viewed in a rotational axis direction of the photosensitive member, the first contact surface, the second contact surface, the first support surface, and the second support surface each extend in a direction intersecting an irradiation direction of the laser light directed from the housing toward the photosensitive member, a cartridge including the photoreceptor; a first cartridge support portion to which one end of the cartridge in the axial direction of the photosensitive member is attached, and a second cartridge support portion to which the other end of the cartridge, which is opposite to the one end in the axial direction, is attached, the first cartridge support portion is attached to one end side of the frame in the axial direction, the second cartridge support portion is attached to the other end side of the frame opposite to the one end side in the axial direction; An image forming apparatus characterized by:

11. The first support portion and the second support portion are separate.

11. The image forming apparatus according to claim 10.

12. In a direction in which the laser light travels from the housing to the photosensitive body, the first contact surface is located downstream of the second contact surface.

11. The image forming apparatus according to claim 10.

13. The first abutment surface, the second abutment surface, the first support surface, and the second support surface extend in a substantially horizontal direction.

11. The image forming apparatus according to claim 10.

Images