Image forming apparatus

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] An image forming apparatus to which an electrophotographic image forming process is applied forms a latent image by scanning a laser beam emitted from a laser scanner on the surface of a photosensitive drum along the axial direction of the photosensitive drum. While scanning the laser beam in the main scanning direction, the photosensitive drum is rotated, and the laser beam is scanned in the main scanning direction in a sub-scanning direction perpendicular to the main scanning direction, so that an image is formed. At this time, if the laser scanner vibrates in the sub-scanning direction, the irradiation position of the laser beam on the surface of the photosensitive drum is also shifted in the sub-scanning direction, and the latent image is moved (shifted) in the sub-scanning direction from its original position. Since the shift in the sub-scanning direction appears in the image as blurring or banding, a configuration that is less likely to vibrate in the sub-scanning direction is required for the scanner unit. Therefore, for example, a configuration has been proposed in which a hollow elastic member and a leaf spring are used in the connection between the main frame and the scanner unit to make it difficult for vibrations generated in the main frame to be transmitted to the scanner unit (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-003329 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional image forming apparatuses require many parts, such as elastic members and leaf springs, which makes the configuration complicated and increases costs. For this reason, there is a demand for reducing the number of parts and costs while increasing rigidity against vibration.

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

[0006] In order to solve the above-mentioned problems, the present invention has the following configuration. (1) An image forming apparatus for forming an image on a recording material, comprising: a photosensitive member; an exposure device for forming a latent image on the photosensitive member; a cylinder forming a space for accommodating at least a portion of the exposure device; a support portion arranged within the space of the cylinder along the direction of a rotational axis of the photosensitive member and supporting the exposure device; a first side plate fixed to one end of the cylinder in the direction of the rotational axis; and a second side plate fixed to the other end of the cylinder in the direction of the rotational axis, wherein the support portion has one end fixed to the first side plate and the other end fixed to the second side plate in the direction of the rotational axis. Effect 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 description of the drawings]

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

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

[0010] [Overall configuration of image forming device] An outline of the overall configuration of an image forming apparatus will be described with reference to FIG. 1. Here, the image forming apparatus includes, for example, an electrophotographic copying machine, an electrophotographic printer (such as an LED printer or a laser beam printer), an electrophotographic facsimile machine, and an electrophotographic word processor. The image forming apparatus also includes a monochromatic or full-color image forming apparatus used as an output device such as a multifunction machine or a workstation that has a function of forming an image on a recording material. FIG. 1 is a cross-sectional view showing a schematic configuration of a laser beam printer (hereinafter, referred to as a printer) 1, which is an example of an image forming apparatus. The recording material is a material on which an image is formed by an electrophotographic image forming apparatus, and includes, for example, paper, an OHP sheet, and the like.

[0011] The printer 1 includes a recording material supplying 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 onto the recording material S, and a recording material discharging section 40 that discharges the recording material S with the image fixed thereon to the outside of the machine. The recording material supplying section 10 is disposed at the bottom of the printer 1 and is configured to accommodate the recording material S. The recording material supplying 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 accommodated recording material S to the image forming section 20.

[0012] The image forming section 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 a 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 section 30 heats and fixes the unfixed toner image by passing the recording material S through a nip section 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 section 40, the recording material S that has been heated and fixed is discharged to the outside of the printer 1 by the conveying force of a pair of discharge rollers 41, and is stacked above a discharge tray 47 and a discharge extension tray 48. Here, the left side in Fig. 1 where the paper feed tray 11 and the discharge extension tray 48 are provided will be referred to as the "front side (FRONT)", and the right side in Fig. 1 where the double-sided transport path is provided will be referred to as the "rear side (REAR)". Additionally, the upper side in Fig. 1 where the discharge 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 be described. First, based on an image signal from a control unit (not shown) provided in the printer 1 that has received a print command, a laser scanner 21 irradiates a laser beam onto the photosensitive drum 22. 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 starts rotating counterclockwise at a predetermined timing. After that, when a command to start paper feeding is received from the control unit, the paper feed arm 16 moves down counterclockwise around the transport roller 13. The paper feed roller 12 comes into contact with the topmost sheet of the stack of recording materials 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 moves up clockwise in the opposite direction to the previous movement, and the paper feed roller 12 moves away from the recording material S. If multiple sheets of recording materials S are sent to the transport roller 13 at the same time, only the topmost 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 section 20 including the photosensitive drum 22 and the transfer roller 24. In the image forming section 20, the toner image formed on the surface of the photosensitive drum 22 is transferred to the surface of the recording material S as described above. Thereafter, the recording material S to which the unfixed toner image has been transferred is conveyed to the image fixing section 30. In the image fixing section 30, the recording material S passes through a fixing nip section formed by a fixing pressure roller 31 rotating clockwise and a fixing heat roller 34 which is driven to rotate counterclockwise by the fixing pressure roller 31. The fixing heat roller 34 includes a fixing heater therein, and presses the recording material S in the fixing nip section and heats 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 that is provided in the recording material discharge section 40 and forms a nip portion 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 on a discharge tray 47 and a discharge extension tray 48, for example, with the image transfer surface facing down. The discharge tray 47 is disposed below the nip portion of the discharge roller pair 41, and the following recording material is sequentially stacked on top of the discharged recording material S.

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

[0018] [Frame composition] The frame configuration of the printer 1 will be described with reference to FIG. 8. FIG. 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. FIG. 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 mounting the image forming unit 20 and the image fixing unit 30 described in FIG. 1. The right side plate 73 and the left side plate 74 are provided with mounting 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 forming two sides of a triangle, and a sub-frame 53, which is a second frame forming 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] 2, the scanner frame 51 is formed by fastening a main frame 52 and a sub frame 53 to each other. 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 part 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 parts of the laser scanner 21 of the first embodiment. FIG. 6 is a perspective view of the scanner frame 51 constructed by arranging the laser scanner 21 on the main frame 52 supporting the scanner stay 50, fixing it with a spring described later, and fastening the subframe 53 to the main frame 52. The scanner stay 50 is provided in the space Sp (FIGS. 2 and 6) (within the space) of the scanner frame 51 and supports the laser scanner 21. As shown in FIG. 2 and FIG. 3, the scanner stay 50 has a cross-sectional shape (hereinafter referred to as the cross-sectional shape) (cross-sectional shape perpendicular to the left-right direction) that is approximately Z-shaped. The scanner stay 50 extends in the left-right direction, that is, it is installed so that the longitudinal direction is the same as the rotation 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 has 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 perpendicular to the longitudinal direction of the scanner stay 50, which is composed of the fixed portion 50A, the connecting portion 50B, and the scanner positioning portion 50C, is approximately Z-shaped. Also, 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 may be angles other than approximately 90°. Also, the cross-sectional shape perpendicular to the longitudinal direction of the scanner stay 50, which is composed of the fixed portion 50A, the connecting portion 50B, and the scanner positioning portion 50C, may be other shapes such as a U-shape (approximately U-shape).

[0022] (Laser scanner installation) The main frame 52 has a first surface 52A, which is a first surface forming one of two sides of a triangle in a cross section perpendicular to the longitudinal direction, and a second surface 52B, which is a second surface forming the other side (FIGS. 2 and 3). The main frame 52 has a substantially L-shaped cross section, and the first surface 52A functions as a support part that supports the laser scanner 21 in the vertical direction, and the second surface 52B is substantially perpendicular to the first surface 52A and supports the scanner stay 50. The subframe 53 has an opening 53A through which the laser light passes so that the laser light irradiated from the laser scanner 21 is not obstructed. The subframe 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 first surface 52A and the second surface 52B of the main frame 52 which are perpendicular to each other. In this manner, the space Sp having a triangular cross section described above is formed by the three surfaces, namely, 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 a front enlarged view of the mounting portion of the laser scanner 21 of 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 a lower end extending in the left-right direction, an edge 52A2 which is an upper end extending in the left-right direction, an edge 52A3 which is one end in the left-right direction extending in the up-down direction, and an edge 52A4 which is the other end in the left-right direction extending in the up-down direction. The laser scanner 21 is inserted into the space Sp through the opening 52C from the front side as shown by the arrow A in FIG. 3, and is installed on the scanner stay 50. At this time, the scanner positioning portion 50C of the scanner stay 50 is provided with at least two through holes, and each of the two bosses 21C protruding downwardly and facing the laser scanner 21 is in a state of penetrating the through holes as shown in FIG. 2. As a result, the laser scanner 21 is positioned in the front-rear and left-right directions while being allowed to move in the up-down direction with respect to the scanner positioning portion 50C.

[0024] Further, 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. On the other hand, 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, 4, etc., they may be provided at one location or at three or more locations.

[0025] 5 is a rear side enlarged view of the mounting portion of the laser scanner 21 of the first embodiment. As shown in FIG. 5, the laser scanner 21 is provided with a second abutment 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 abutment portion 21B on the tip side in the direction of insertion into the opening 52C. On the other hand, the scanner stay 50 is provided with a stay-side abutment portion 55, which is a second abutment portion, at a predetermined position in the longitudinal direction (left-right direction) so as to abut against the second abutment portion 21B of the laser scanner 21. The stay-side abutment portion 55 is formed so as to partially protrude in the extension direction of the connection portion 50B from the other end opposite to the one end connected to the fixing portion 50A of the connection portion 50B of the scanner stay 50, without being bent from the connection portion 50B to become the scanner positioning portion 50C. The laser scanner 21 is inserted into the space Sp, and 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 vertical 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 at one location in Figs. 3, 5, etc., they may be provided at 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 of them 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 by the restoring force of the elastic deformation of the frame-side spring 56, which is a fixing means. A hole 54D and a spring retaining portion 54E are provided in the vicinity of the frame-side contact portion 54 of the first surface 52A of the main frame 52. The first contact portion 21A of the laser scanner 21 is provided with a spring receiving portion 21A1 for hooking the frame-side spring 56. The frame-side spring 56 is a wire spring in which an engagement portion (hooking portion 56A) with the spring receiving portion 21A1 is provided between an engagement portion with the hole 54D and an engagement portion with the spring retaining portion 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 top side on the spring retaining portion 54E. A hook portion 56A is provided at the middle portion of the frame-side spring 56 so as to be hooked on 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 the top to the bottom toward the frame-side contact portion 54, restricting the movement of the laser scanner 21 in the up-down direction. For example, the worker inserts one end of the frame-side spring 56 into the hole 54D and hooks the hook portion 56A from the top of the spring receiving portion 21A1 of the laser scanner 21. Then, the worker pushes the frame-side spring 56 downward and hooks the other end of the frame-side spring 56 from the bottom to the spring fastener portion 54E, thereby fixing the laser scanner 21 to the first surface 52A of the main frame 52.

[0027] The second contact portion 21B also fixes the laser scanner 21 by biasing the laser scanner 21 downward by the restoring force of the elastic deformation of the stay-side spring 57, which is a fixing means. 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. The second contact portion 21B of the laser scanner 21 is provided with a spring receiving portion 21B1 for hooking the stay-side spring 57. The stay-side spring 57 is a wire spring in which an engagement portion (hooking portion 57A) with the spring receiving portion 21B1 is provided between an engagement portion with the hole 55A and an engagement 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 back 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 on the spring receiving portion 21B1 of the second contact portion 21B. The stay-side spring 57 biases the spring receiving portion 21B1 of the laser scanner 21, and therefore the second contact portion 21B, from the top to the bottom toward the stay-side contact portion 55, restricting the movement of the laser scanner 21 in the up-down direction. For example, the worker inserts one end of the stay-side spring 57 into the hole 55A and hooks the hook portion 57A from the top of 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 from the bottom to the spring fastener portion 55B, 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, 5, etc. Therefore, the method 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 also not limited to the mode shown in Figure 4. Furthermore, the method 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 also not limited to the mode shown in Figure 5. The fixing means may also be, for example, a screw instead of a spring.

[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. In addition to main frame 52, which is a first frame, and sub-frame 53, which is a second frame, scanner frame 51 according to the first embodiment has a right frame 70 provided on the right and a left frame 71 provided on the left of main frame 52 and sub-frame 53. 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 of printer 1 main body.

[0030] As described later, the main frame 52 and the sub-frame 53 are connected by being swaged at a plurality of locations. At the left and right ends of the scanner frame 51, the right frame 70 and the left frame 71 are fastened to one end and the other end of the main frame 52 and the sub-frame 53, respectively, by fastening screws 75 (FIG. 8). In this manner, the scanner frame 51 is configured to have a box shape, and a space Sp is located 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 configured to 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] As shown in Fig. 3, the scanner stay 50 extends left and right so as to connect between the right frame 70 and the left frame 71 arranged on the left and right sides of the main body of the printer 1. At the left and right ends of the scanner stay 50, screws 78 (Fig. 8) are fastened to stay fastening parts 72 (left side not shown) via through holes provided in the right frame 70 and the left frame 71, respectively. In this manner, one end of the scanner stay 50 in the longitudinal direction is fixed to the right frame 70, and the other end of the scanner stay 50 in the longitudinal direction is fixed to the left frame 71. In particular, the screws 78 are provided in the parts of the right frame 70 and the left frame 71 that overlap with the triangular end face areas 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 shape 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 plate, for example, made of resin, as long as the rigidity of the scanner stay 50 itself is ensured and the scanner stay 50 itself is not easily bent. 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 and the connecting portion 50B.

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

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

[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. Also, a connection portion of the second surface 52B of the main frame 52 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 protruding from one connection portion adjacent to the first surface 52A of the main frame 52 and 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 crimping portion 58 is arranged so that the crimping shaft 58B of the main frame 52 penetrates 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 of the second surface 52B of the main frame 52. The crimping shaft 58B is crimped and plastically deformed, so that the subframe 53 is sandwiched between the deformed portion of the crimping 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 of 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 of the second surface 52B of the main frame 52 at the crimping 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 connected to the first surface 52A of the main frame 52 so as to be adjacent to each other, 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 to each other by burring crimping, but the fastening means is not limited to this and may be, for example, other crimping means, screw fastening, welding, or the like.

[0038] (effect) In the first embodiment, the scanner frame 51 is formed in a box shape such that the main frame 52 and the sub frame 53 connect between the right frame 70 and the left frame 71 arranged on the left and right sides of the printer 1 body. In other words, the main frame 52 and the sub frame 53 are configured to have a triangular cross section perpendicular to the longitudinal direction. This can increase the rigidity against torsion around the axis extending in the longitudinal direction. In addition, 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 can increase the rigidity against torsion around the axis extending in the longitudinal direction, and can suppress deformation of the first surface 52A and the second surface 52B of the main frame 52, which are the sides of the triangle in the cross section perpendicular to the longitudinal direction, and the sub frame 53, which are deflected inward and outward in the space Sp. Here, in the first embodiment, the scanner stay 50 is fixed to the right frame 70 and the left frame 71, respectively, and is configured to connect between the right frame 70 and the left frame 71. With this configuration, even if the second surface 52B of the main frame 52 is deflected, the scanner stay 50 and the laser scanner 21 can be prevented from being displaced. Furthermore, the screw 78 is provided in the right frame 70 and the left frame 71 that overlap the triangular end surface area 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 the right frame 70 and the left frame 71 that are less likely to deform when an external force is applied, and the scanner stay 50 can be prevented from being displaced. With this configuration that suppresses the twisting of the scanner frame 51 and the deflection of the members that constitute the scanner frame 51, the vibration that displaces the laser scanner 21 in the sub-scanning direction is suppressed, and the vibration rigidity of the scanner frame 51 can be increased.

[0039] In particular, in the first embodiment, at least at the ends of the main frame 52 and the subframe 53 in the longitudinal direction, no notches or holes are formed, and the cross section perpendicular to the longitudinal direction surrounding the space Sp is configured to be a continuous ring shape. In other words, 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 subframe 53, which form a triangular ring shape, so that the scanner frame 51 is configured. Specifically, when a cross section is taken at the longitudinal center of the scanner frame 51, the first surface 52A of the main frame 52 has an opening 52C, and the subframe 53 has an opening 53A, so that the cross section is not a triangular ring shape, but a state in which the sides of the triangle are interrupted. However, at least at one end and the other end of the scanner frame 51, there are no such openings, and the cross section is a triangular ring shape with continuous sides. This allows the right frame 70 and the left frame 71 to be firmly fixed to the main frame 52 and the subframe 53, respectively, and increases the rigidity against sudden external forces and deformation in the torsional direction. By fixing the scanner stay 50 to the scanner frame 51 with high rigidity, it is possible to suppress vibration propagation to the laser scanner 21 and suppress 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 side plate 73 and the left side plate 74. In addition, if the rigidity of the scanner frame 51 can be ensured, for example, the plate thickness of the subframe 53 may be made thinner than that of the main frame 52, or the main frame 52 and the subframe 53 may be integrated, thereby reducing material costs and the number of parts. In addition, the scanner frame 51 may be configured using three frames having the crimping parts 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 at least the stay fastening portions 72 (FIG. 3) at both ends in the longitudinal direction 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 deflected, the scanner stay 50 will not be affected.

[0041] As described above, according to the first embodiment, the vibration stiffness of the scanner unit can be increased with a simple configuration. In this case, since the stiffness can be increased only in the places where high vibration stiffness is required, unnecessary increase in cost due to excessive stiffness can be eliminated. In addition, since the torsional stiffness around the scanner unit can be secured, a configuration that is more resistant to plastic deformation due to shock during transportation can be realized.

[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 to the laser scanner 21 after each member such as the photosensitive drum 22 is positioned based on the laser scanner 21. Therefore, by configuring the scanner frame 51 of the scanner unit to have an increased rigidity, the positioning accuracy of each member such as the photosensitive drum 22 relative to the laser scanner 21 can be improved.

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

[0044] [Laser scanner configuration] Fig. 9(a) is a top perspective view of the laser scanner 21, which is a scanning optical 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 by a resin or metal optical cover (not shown), and the inside of the laser scanner 21 is sealed.

[0045] An optical deflector 211 for deflecting the laser light and various optical members are arranged inside the housing 203 of the laser scanner 21. The optical deflector 211 has a rotary polygon mirror 213 for deflecting the optical path of the incident laser light, a scanner motor 212 for rotating the rotary polygon mirror 213, a control IC for controlling the rotation of the scanner motor 212, and the like. The optical deflector 211 for deflecting the laser light L may use a resonant 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 direction of rotation of the photosensitive drum 22) is referred to as the sub-scanning direction.

[0046] The laser light L emitted from the laser diode 201, which is a light source, in response to image information is converted by the composite anamorphic collimator lens 202 into substantially parallel light or convergent light in the main scanning direction and into convergent light in the sub-scanning direction. The laser light L that has passed through the composite anamorphic collimator lens 202 is limited to a predetermined beam diameter by an optical diaphragm 204 formed in a housing 203. The laser light L that has passed 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 a reflecting surface of the rotary polygon mirror 213. The deflected laser light L proceeds to an fθ lens 205, and after passing through the fθ lens 205, is collected on the photosensitive drum 22 from an opening (emission port) provided in the housing 203 through which the laser light L passes, and forms an electrostatic latent image on the photosensitive drum 22. In FIG. 9(a), the dashed line indicates the range in the main scanning direction in which the laser light L deflected by the rotating polygon mirror 213 is emitted.

[0047] Next, the two first abutment parts 21A and the second abutment part 21B, which are the mounting seating surfaces, will be described. FIG. 9(b) is a perspective view showing the bottom surface of the laser scanner 21, in which the upper left side is the bottom surface of the front side of the housing 203 where the opening (emission port) from which the laser light is emitted is provided, and the lower right side is the bottom surface of the front side of the housing 203 where the optical deflector 211 is installed. A total of three abutment parts, two first abutment parts 21A and one second abutment part 21B, are provided on the bottom surface of the laser scanner 21. The mounting reference surface is a seating 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, and in this modified example, it has a square shape of about 5 mm x 5 mm, and the surface is 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 exit port of the laser light L. 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 side of the exit port of the laser light of the laser scanner 21. In this modification, one mounting reference surface is provided on the side of the exit port of the laser light L on the bottom surface of the housing 203, and two on the side where the optical deflector 211 is installed, but two may be provided on the side of the exit port of the laser light L and one on the side where the optical deflector 211 is installed.

[0048] As described later, the two first contact portions 21A and the two second contact portions 21B are inclined surfaces having 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 contact portions 21A and the second contact portions 21B are in contact with the scanner stay 50 and the main frame 52. Furthermore, two spring receiving portions 21A1 and 21B1 protruding from the housing 203 are provided on the outer periphery of the housing 203 at positions facing the two first contact portions 21A and the two second contact portions 21B in the longitudinal direction (also the main scanning direction) of the housing 203. As described later, the two spring receiving portions 21A1 and 21B1 are provided to bias the laser scanner 21 against the scanner stay 50 and the main frame 52 by the stay side spring 57 and the frame side spring 56 (see FIGS. 10 and 11). 9B is a boss hole for supporting the rotation shaft of the scanner motor 212 of the optical deflector 211. As shown in FIG.

[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 for explaining 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 shaft of the scanner motor 212 of the optical deflector 211 of the laser scanner 21. Note that Fig. 10 omits the display of the main frame 52 that is located 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 a state in which 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, so that the laser scanner 21 is supported by the scanner stay 50 and the main frame 52. The stay-side abutment portion 55 refers to the abutment surface of the end portion that abuts 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 portion that abuts against the two first abutment portions 21A of the main frame 52. Also, in FIG. 10, one of the first abutment portions 21A is not shown. The dashed lines indicate the optical path of laser light L that is emitted from a laser diode 201 (not shown in FIG. 10) and deflected by a rotating polygon mirror 213 driven by a scanner motor 212 of an optical deflector 211, and scans 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 (X-axis direction in the drawing) with respect to the photosensitive drum 22. As shown in FIG. 10, the angle θ is an angle with respect to a rotating polygon mirror 213 (or the bottom surface of the housing 203 of the laser scanner 21) that 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 to have 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 contact portion 21A and the second contact portion 21B contact the frame side contact portion 54 of the main frame 52 and the stay side contact portion 55 of the scanner stay 50, the entire mounting reference surface comes into contact (surface contact). Note that, although one of the first contact portions 21A is not shown in Fig. 10, it contacts the frame side contact portion 54 (not shown) of the main frame 52 with a configuration similar to that of the first contact portion 21A shown in Fig. 10.

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

[0053] [Main frame configuration] Here, the configurations of the scanner stay 50 and main frame 52 shown in Fig. 10 and the method of supporting the laser scanner 21 by the wire spring will be described. Fig. 11(a) is a perspective view showing the main frame 52, sub-frame 53, and the scanner stay 50 attached to the scanner frame 51, which are members constituting the scanner frame 51, disassembled into individual members.

[0054] The subframe 53 has four faces 53c, 53d, 53e, and 53f adjacent to the face 53b, with the face 53b at the center. The face 53b has an opening 53A in the center to allow the laser light emitted from the laser scanner 21 to pass through. The faces 53c and 53d on both sides of the face 53b in the left-right direction in the figure are provided for connecting to a side panel frame (not shown) provided on the side of the printer 1, and the round holes in the figure are screw holes for connecting to the side panel frame. The face 53e adjacent to the upper side of the face 53b in the figure has a screw hole for connecting to the face 52C of the main frame 52. The face 53f adjacent to the face 53b has a screw hole (not shown) for fixing the subframe 53 to the bottom surface of the housing of the printer 1, and the scanner frame 51 is fixed to the printer 1 by fixing the face 53f to the printer 1, thereby increasing 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 a hole for connecting the scanner stay 50 to the main frame 52 with a screw 103 (see FIG. 10). FIG. 10 shows a state in which the scanner stay 50 is screwed to the main frame 52. On the other hand, 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 connection portion 50B at an equal distance from the spring receiving portion 21A1 of the housing 203, and bending the cut portions perpendicular to the connection portion 50B.

[0056] The main frame 52 is formed by bending a sheet metal into an L-shape and by 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 a surface provided for connecting to the surface 53e of the subframe 53, and is provided with a screw hole for screwing to the surface 53e of the subframe 53. The first surface 52A is provided with a screw hole for connecting to the scanner stay 50, as well as a screw hole 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 the laser scanner 21 is attached and detached. Moreover, 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] In addition, three spring retaining portions 54E protruding from the second surface 52B are provided near the edge 52B1 of the opening in order to bias the spring receiving portion 21A1 and the spring receiving portion 21B1 of the housing 203 with the frame side spring 56. The three spring retaining portions 54E are formed by cutting portions near the edge 52B1 of the second surface 52B equidistant from the spring receiving portion 21A1 and the spring receiving portion 21B1 of the housing 203 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 direction opposite to the side where the opening from which the laser light L is emitted is provided, and it can be seen that the spring receiving portions 21A1 of the two first abutting portions 21A biased by the frame side spring 56 are provided on the end side 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 the edge portion 52B1 of the main frame 52. In FIG. 11(b), two spring receiving 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 the 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 (surfaces facing downward in the figure) of the respective claw portions. On the other hand, for the two spring receiving 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 (surfaces facing upward in the figure) of the respective claw portions. Furthermore, the frame-side spring 56 is bent into a crank shape between a claw portion provided on the housing 203 of the laser scanner 21 and a claw portion provided on the main frame 52 according to the height of each claw portion. Although not shown in Fig. 11(b), the spring receiving 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 abutment portion 55 of the scanner stay 50 and the edge portion 52B1 of the main frame 52 via the two first abutment portions 21A and the second abutment portion 21B. The vibration of the laser scanner 21 caused by the scanner motor 212 of the optical deflector 211 is not easily transmitted in a direction perpendicular to the plane of the scanner stay 50 and the main frame 52. Therefore, it is possible to reduce the bending of the connection portions 50B and 52B (see FIG. 11(a)) configured in the vertical direction (Y-axis direction in FIG. 10) of the scanner stay 50 and the main frame 52. As a result, it is possible to reduce the vibration of the laser scanner 21 in the sub-scanning direction (Y-axis direction in FIG. 10) without adding a reinforcing member. Furthermore, it is possible to suppress the deterioration of image quality, such as pitch unevenness, caused by the irradiation position on the photosensitive drum 22 of the laser light L emitted from the laser scanner 21 periodically shifting in the sub-scanning direction (rotation direction of the photosensitive drum 22).

[0060] 10, the laser light L from the laser scanner 21 is irradiated obliquely onto the photosensitive drum 22, so that 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 contact portions 21A and the second contact portion 21B and the 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 abutment parts 21A and the second abutment parts 21B are substantially parallel to the stay-side abutment part 55 and the edge part 52A1, so that the two first abutment parts 21A and the second abutment parts 21B are in surface contact with the stay-side abutment part 55 and the edge part 52B1, and the laser scanner 21 can be stably installed. In particular, in this modified example, as shown in FIG. 11(a), the connection part 50B of the scanner stay 50 is bent perpendicularly to the fixed part 50A. Similarly, the second surface 52B of the main frame 52 is bent perpendicularly to the first surface 52A. As a result, the two first abutment parts 21A and the second abutment parts 21B provided on the housing 203 of the scanning optical device are in surface contact with the stay-side abutment part 55 of the scanner stay 50 and the edge part 52B1 of the main frame 52 on a horizontal surface. 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 receive 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 abutment parts 21A and the second abutment part 21B provided on the housing 203 of the laser scanner 21 come into surface contact with the stay-side abutment part 55 of the scanner stay 50 and the edge part 52B1 of the main frame 52. Therefore, the two first abutment parts 21A and the second abutment part 21B do not come into contact with the stay-side abutment part 55 of the scanner stay 50 and the corners of the edge part 52B1 of the main frame 52, so that it is possible to prevent the two first abutment parts 21A and the second abutment part 21B from being scraped off due to contact with the stay-side abutment part 55 and the corners of the edge part 52B1. This prevents the scraps of the two first abutment parts 21A and the second abutment part 21B from scattering inside the printer 1, and also prevents the support accuracy of the laser scanner 21 from being reduced due to the scraping of the two first abutment parts 21A and the second abutment part 21B.

[0062] In addition, in this modification, the laser scanner 21 itself is tilted to set an angle to the laser light L irradiated to 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, the space required for arranging the folding mirror and the like inside the laser scanner 21 can be reduced, and the laser scanner 21 can be made smaller and less expensive.

[0063] Furthermore, in this modified example, the laser scanner 21 is installed at an angle so that the laser light L can be irradiated obliquely downward onto the photosensitive drum 22. Therefore, the installation position of the laser scanner 21 can be arranged at a lower position than the position in which the laser light L is irradiated onto the photosensitive drum 22 horizontally. This makes it possible to reduce the height of the printer 1, for example, by lowering the 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 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 ends of the scanner stay 50 and the main frame 52 in the longitudinal direction (main scanning direction) are in contact with a side plate frame (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, so that no additional support member is required, and the cost increase of the printer 1 can be suppressed. As a result, the degree of freedom in arranging the laser scanner 21 in the printer 1 is improved, and a small and low-cost printer 1 can be provided.

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

[0066] FIG. 12 is an exploded view of peripheral parts of the laser scanner 21 of the second embodiment. FIG. 13 is an enlarged rear view of the mounting portion of the laser scanner 21 of the second embodiment. With reference to FIGS. 12 and 13, the second embodiment, which has a different support configuration for the laser scanner 21, will be described. The main change from the first embodiment 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 the second embodiment, the changes from the first embodiment will be mentioned, and the other configurations are the same as those of the first embodiment, so the description will be omitted.

[0067] In the second embodiment, the stay-side abutment portion 55 and the stay fastening portion 72 are formed on the second surface 52B of the main frame 52. In addition, the hole 55A and the spring retaining portion 55B are also provided on the second surface 52B of the main frame 52. In the second embodiment, the number of parts can be further reduced, and a simpler configuration can be achieved. The shape of the portion corresponding to the scanner stay 50 is a substantially U-shaped cross section perpendicular to the longitudinal direction with an opening at the bottom. Furthermore, the left and right ends, which are both ends in the longitudinal direction of the portion corresponding to the scanner stay 50, are provided with convex portions 77 protruding toward the outside. On the other hand, the right frame 70 and the left frame 71 are provided with openings 76 at positions corresponding to the convex portions 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 state where the frames are positioned by inserting the protrusions 77 provided on both the left and right ends into the openings 76 provided in the right frame 70 and the left frame 71, respectively. By positioning in this manner, the rigidity of the scanner frame 51 is ensured.

[0070] 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 makes it easy to position the scanner stay 50 relative to the right frame 70 and the left frame 71 in the first embodiment as well, and makes it possible to increase the rigidity of the scanner frame 51. Furthermore, in the case of 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 relative to the right frame 70 and the left frame 71.

[0071] As described above, according to the second embodiment, it is possible to increase the vibration stiffness of the scanner unit 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 be used as long as the necessary rigidity is satisfied. For example, in the above embodiment, the laser scanner 21 is fixed by being biased by a spring, but it may be fixed using other fixing means such as a screw. 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 shape does not impair the second moment of area. For example, in the above 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 a plurality of 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 stiffness of the scanner unit can be increased with a simple configuration.

[0073] <Other Modifications> 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, an exterior cover 101 constituting a part of the exterior in this modified example is provided with a pressing 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 with respect to the main frame 52 such that positioning portions 104a and 104b of the exterior cover 101 are inserted into openings provided in the main frame 52. In this state, the exterior cover 101 is attached to the main frame 52 such that the fastening hooks 105a and 105b engage with the main frame 52. In this manner, it is desirable to dispose the pressing portion 102 above the center of gravity of the laser scanner 21.

[0075] With the above configuration, when the printer 1 vibrates due to the operation of the printer 1, the laser scanner 21 is prevented from being largely separated from the main frame 52. For example, when the laser scanner 21 receives a strong impact such as a drop in a physical object, the laser scanner 21 may float in a direction away from the main frame 52 with respect to the direction of the force applied by the stay-side spring 57. However, by disposing the holding portion 102 with a gap between the holding portion 102 and the laser scanner 21 as shown in FIG. 16, the elastic force of the stay-side spring 57 can be utilized to cushion the impact against a certain level of impact, and the laser scanner 21 is supported by the holding portion 102 to cushion the applied impact against an impact exceeding the certain level. Note that the holding portion 102 may be configured to be interposed between the laser scanner 21 and another component, and the laser scanner 21 may be supported by another member via the holding 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, the gap is preferably 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, even if the opening of the main frame 52 cannot be narrowed, it is possible to prevent the laser scanner 21 from coming off the main frame 52. For example, this is also effective in cases where there is a large gap between the laser scanner 21 and the opening of the main frame 52, such as a configuration in which the laser scanner 21 has a protrusion 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 can also improve service workability.

[0078] In this modified example, exterior cover 101 is configured to be constantly fixed to main frame 52. However, as shown in Fig. 17 and Fig. 18, exterior cover 101 that can be opened and closed about rotation fulcrum 106 may have pressing portion 102. Here, Fig. 17 is an external perspective view showing the exterior cover and main frame of the modified example, and Fig. 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 photoconductor; an exposure device that irradiates a surface of the photoconductor with a laser beam so that an electrostatic latent image is formed on the photoconductor; 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 constituting 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 contact 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, 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; 1. An image forming apparatus comprising:

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

2. The image forming apparatus according to claim 1,

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

2. The image forming apparatus according to claim 1,

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,

5. A cartridge including the photoconductor; a first cartridge support portion to which one end side of the cartridge in an axial direction of the photosensitive member is attached, and a second cartridge support portion to which the other end side of the cartridge, which is opposite to the one end side 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,

Images