JP2009075447A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which vibration of an optical scanning unit is suppressed, workability in attaching/detaching the optical scanning unit is improved and size and cost are reduced. <P>SOLUTION: The image forming apparatus includes: a rear side scanner support member 27 and a front side scanner support member 28, which are disposed on the front side and rear side, respectively, of the main body of the image forming apparatus in the direction of attaching/detaching a laser scanner device 5, and which support the laser scanner device 5; and a guide mechanism (guide rail 29, the projecting rib 5b of the laser scanner device) which is composed by engaging the laser scanner device 5 with the main body of the image forming apparatus in the lateral direction of the laser scanner device 5, i.e., a direction substantially perpendicular to the attached/detached direction, and which guides the movement of the laser scanner device 5 in the attached/detached direction. The guide mechanism is disposed so as to guide only one end of the lateral direction of the laser scanner device 5. When the laser scanner device 5 is attached/detached, the guide mechanism regulates the lateral position of the laser scanner device 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer employing an electrophotographic system.

  In an image forming apparatus that employs a general electrophotographic system, a laser scanner device that uses a laser beam as a means (optical scanning unit) for forming an electrostatic latent image on a photoreceptor as an image carrier is used. This laser scanner device is often unitized and can be attached to and detached from the image forming apparatus main body during cleaning and inspection.

  In addition, the positional relationship between the photosensitive member and the laser scanner device needs to be positioned with high accuracy in order to obtain high image quality.

  Therefore, when the laser scanner device is housed in the image forming apparatus main body, the positioning pin of the laser scanner device (or the positioning hole of the laser scanner device with respect to the positioning pin on the device main body side) is set to the positioning hole on the device main body side. A predetermined positioning is performed by fitting.

  However, in such a case, the pin and the hole on the back side in the insertion direction must be fitted inside the device main body in a limited space, and this positioning operation is usually difficult to visually confirm. There was a problem that the work required time.

  Further, if the laser scanner device vibrates, there is a concern that the image may be striped, and it is necessary to suppress the vibration of the laser scanner device. When the laser scanner device is supported by one large planar support member, there is a concern that the support member vibrates at a low frequency and the laser scanner device is likely to resonate greatly.

  Therefore, the vibration can be suppressed by dividing the support member into two and taking a means for strengthening each support member (for example, making the plate U-shaped). However, since the support member is divided, there is a concern that the laser scanner device may drop into the space between the two support members when the laser scanner device is housed in the image forming apparatus main body.

In order to solve such a problem, a conventional image forming apparatus has guide rails that support the lower surfaces of the left and right ends of the laser scanner device with respect to the insertion direction and guide them while regulating the left and right directions. Yes (see Patent Document 1).
JP 2004-50671 A

  However, in the conventional example as described above, it is necessary to dispose two guide rails at both the left and right ends of the laser scanner device, which requires a space for that purpose, and there is a concern that the size of the image forming apparatus main body becomes large. Is done.

  Moreover, there is a concern that the cost for two guide rails will increase.

  Also, when inserting the laser scanner device into the main body of the image forming apparatus, it is necessary to match both the left and right ends of the laser scanner device with the entrance shape of the guide rail. Especially in the case of a large-sized laser scanner device, the left and right ends are visually checked. There is a concern that it will be difficult.

  The present invention has been made in view of the circumstances as described above, and suppresses vibration of the optical scanning unit, improves detachability of the optical scanning unit, and achieves image size reduction and cost reduction. An object is to provide an apparatus.

In order to achieve the above object, the present invention provides:
At least one image carrier;
An optical scanning unit that forms an electrostatic latent image on the image carrier by irradiating a laser beam in accordance with an image signal and scanning the image carrier;
In the image forming apparatus provided with the optical scanning unit detachably with respect to the image forming apparatus main body,
Two support members which are provided apart from the front side and the back side of the image forming apparatus main body with respect to the mounting direction of the optical scanning unit and support the optical scanning unit;
The optical scanning unit and the image forming apparatus main body are engaged with each other in the left-right direction of the optical scanning unit that is substantially perpendicular to the attaching / detaching direction, and the optical scanning unit moves in the attaching / detaching direction. One guide mechanism for guiding
With
The guide mechanism is provided so as to guide only one end side in the left-right direction of the optical scanning unit, and the optical scanning is performed with the image forming apparatus installed when the optical scanning unit is attached or detached. The position of the unit in the left-right direction is restricted.

  According to the present invention, it is possible to provide an image forming apparatus that suppresses vibration of the optical scanning unit, improves attachment / detachment workability of the optical scanning unit, and realizes downsizing and cost reduction.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

  Hereinafter, an image forming apparatus according to Embodiment 1 of the present invention will be described in detail with reference to the drawings.

  FIG. 9 is a schematic configuration diagram of the image forming apparatus according to the present embodiment as viewed from the front.

  In FIG. 9, reference numerals 1Y, 1M, 1C, and 1K denote photosensitive drums as image carriers. The photosensitive drums 1Y, 1M, 1C, and 1K are process cartridges 2Y, 2M, and 2C that include developers (toners) of yellow (Y), magenta (M), cyan (C), and black (K), respectively. , 2K is provided so that both ends thereof are supported rotatably. The photosensitive drums 1Y, 1M, 1C, and 1K are driven and transmitted from one end by a drive motor and drive transmission means (not shown), and are driven to rotate clockwise in FIG.

  An organic photoconductor layer is applied to the surface of each of the photosensitive drums 1Y, 1M, 1C, and 1K.

The image forming operation will be described below. Here, the photosensitive drums 1Y, 1M, 1C, 1
In K, it may be simply referred to as the photosensitive drum 1.

  The surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K are uniformly charged by applying a charging bias to the charging rollers 3Y, 3M, 3C, and 3K. Then, the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K are selectively exposed by laser light emitted from a laser scanner device 5 as an optical scanning unit (optical scanning device, exposure means), and an electrostatic latent image is obtained. Is formed. Here, the laser scanner device 5 forms an electrostatic latent image on the photosensitive drum 1 by irradiating a laser beam in accordance with an image signal while scanning.

  This electrostatic latent image is developed as a toner image by attaching toner of each color by developing means 4Y, 4M, 4C, and 4K.

  The intermediate transfer belt 6 is stretched around a driving roller 7 and a driven roller 8. Then, the intermediate transfer belt 6 is urged by the primary transfer rollers 9Y, 9M, 9C, and 9K to come into contact with the photosensitive drums 1Y, 1M, 1C, and 1K and the rotation of the driving roller 7 in FIG. It is driven to rotate counterclockwise. Here, the drive roller 7 is driven to rotate by a drive motor and drive transmission means (not shown).

  A predetermined transfer bias is applied to the primary transfer rollers 9Y, 9M, 9C, and 9K, and the color toner images on the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K are sequentially superimposed on the intermediate transfer belt 6. Transferred to form a four-color toner image.

  A recording material 11 is loaded on the feeding cassette 10. The recording material 11 is fed by a feed roller 12 driven at a predetermined timing by a drive motor and drive transmission means (not shown), and then passes through a pair of conveying rollers 13 and a pair of registration rollers 14 to transfer the intermediate transfer belts 6 and 2. It is conveyed to a secondary transfer position where the next transfer roller 15 comes into contact.

  At the secondary transfer position, the four color toner images on the intermediate transfer belt 6 are transferred to the recording material 11 by the secondary transfer roller 15 to which a predetermined bias is applied.

  The recording material 11 to which the four color toner images have been transferred is conveyed to the fixing roller pair 16 and the toner image is melted and fixed on the recording material 11 by heat and pressure, whereby a color image is obtained. The recording material 11 conveyed by the fixing roller pair 16 passes through the discharge roller pair 17 and is discharged and stacked on the discharge tray 18.

  The laser scanner device 5 is detachably provided in an arrow A direction from an opening formed by removing the left exterior of the image forming apparatus.

  Next, a guide mechanism for inserting the laser scanner device 5 into the image forming apparatus main body (hereinafter referred to as the apparatus main body), which is a characteristic configuration of the present embodiment, will be described with reference to FIGS.

  FIG. 1 shows an opening on the left side of the apparatus main body, an apparatus main body frame, and internal parts of the apparatus main body.

  In FIG. 1, 20 is a front side plate, 21 is a rear side plate, 22, 23, 24, 25, and 26 are device body support members, and these members are fastened together with screws to form a device body frame that becomes a skeleton. ing.

Reference numeral 27 is a back scanner support member as a back support member, 28 is a front scanner support member as a front support member, and the laser scanner device 5 is constituted by these two support members separated from each other in the attaching / detaching direction. Supported. Here, when the direction in which the laser scanner device 5 is inserted into the apparatus main body is the insertion direction, the upstream side in the insertion direction is the front side, and the downstream side in the insertion direction is the back side. Further, the attaching / detaching direction of the laser scanner device 5 is the arrow A direction shown in FIG. 10 as described above, and among these, the right direction (the direction toward the inside of the device main body) in FIG.

  The scanner support members 27 and 28 are made of a strong sheet metal having a substantially U-shaped cross section in order to suppress the vibration of the laser scanner device 5, and both end portions thereof are screwed to the front side plate 20 and the rear side plate 21, respectively. It is concluded by.

  Reference numeral 29 denotes a guide rail that serves as a guide when the laser scanner device 5 is inserted into the apparatus main body. The guide rail 29 has a substantially U-shaped groove 29a for restricting the horizontal direction (the horizontal direction that is substantially perpendicular to the attachment / detachment direction (insertion direction)) and the downward direction of the laser scanner device 5 at the time of insertion. The entrance has a substantially tapered shape with a wider front side. Here, in the description of the present embodiment, it is assumed that the apparatus main body is installed in the vertical and horizontal directions. Further, a guide rail 29 provided in the apparatus main body and a protruding rib 5b which is a protruding rib provided in the laser scanner device 5 and is regulated (engaged) and guided by the guide rail 29 as described later, A guide mechanism is configured. In this embodiment, only one guide mechanism is provided.

  The laser scanner device 5 is attached to and detached from the device body through the opening 30. Reference numeral 31 denotes a low-voltage power supply device, which is disposed on the lower side of the laser scanner device 5, and is similarly attached to and detached from the opening 30 through the apparatus body.

  FIG. 2 shows the laser scanner device 5.

  In the laser scanner device 5, a laser substrate 5a on which a laser light source (not shown) and its circuit are formed is disposed on one side surface of the box, and a groove portion 29a of the guide rail 29 is formed on the opposite side surface (one end side in the left-right direction). A protruding rib 5b that fits in is formed. Reference numeral 5 c denotes a window through which laser light is emitted toward the photosensitive drum 1. Reference numerals 5 d and 5 e denote back side support protrusions as convex portions supported by the back side scanner support member 27. The back side support protrusions 5d and 5e are provided so as to protrude from the main body of the laser scanner device 5 in the attaching / detaching direction.

  FIG. 3 is a view showing a state in which the laser scanner device 5 is inserted partway into the apparatus main body. FIG. 8 is a cross-sectional view showing a schematic configuration of the guide rail 29 and the protruding rib 5b constituting the guide mechanism.

  When the protruding rib 5b enters (fits or engages) the groove 29a of the guide rail 29, the left-right direction, which is a direction substantially orthogonal to the insertion (detachment) direction of the laser scanner device 5, is restricted. More specifically, the lateral direction of the laser scanner device 5 is restricted by fitting (engaging) the side surface 29a1 of the groove 29a and the side surface 5b1 of the protruding rib 5b. The side surface 29a1 and the side surface 5b1 are surfaces (surfaces provided along the attaching / detaching direction) substantially orthogonal to the left-right direction.

  Moreover, the groove part 29a and the protruding rib 5b constitute a vertical direction lower position restricting part. More specifically, when the protruding rib 5b enters the groove 29a, the lower end 5b2 of the protruding rib 5b contacts the bottom surface 29a2 of the groove 29a of the guide rail 29. Accordingly, the downward movement of the laser scanner device 5 is restricted, and the position of the laser scanner device 5 in the downward direction (vertical downward direction) is restricted.

  Further, the laser scanner device 5 is supported at three points, B, C, and D shown in FIG. Here, in the portion B, the lower end 5b2 of the protruding rib 5b and the bottom surface 29a2 of the groove portion 29a of the guide rail 29 are in contact with each other. Further, in the part C (opening 30, front side of the apparatus main body), the upper part (upper part in the vertical direction) of the laser scanner device 5 and the support member 22 as an upper regulating member are in contact. Further, in the portion D, the bottom portion (lower portion in the vertical direction) of the laser scanner device 5 and the front scanner support member 28 are in contact with each other.

  For this reason, the vertical inclination of the laser scanner device 5 is restricted, and when the laser scanner device 5 is inserted (detached), it contacts each electric element of the low-voltage power supply device 31 positioned below the mounting portion of the laser scanner device 5. It is prevented. Reference numeral 5f denotes a positioning pin that fits into a positioning hole (described later) of the front scanner support member 28, and reference numeral 5g denotes a front support protrusion that is supported by abutting portions (described later) of the front scanner support member 28. . Reference numeral 5h denotes a gripping portion for an operator to grip when the laser scanner device 5 is attached to or detached from the apparatus main body.

  FIG. 4 is a view showing a state of the back side during the insertion of the laser scanner device 5.

  A support hole 27a serving as a recess is formed in the back scanner support member 27, and the spring hooking portions 33, 34, and the back biasing spring 32 serving as the first biasing means close the upper portion of the support hole 27a. 35, 36.

  The distal end of the back support protrusion 5d is tapered, and the backlash in the left-right direction for fitting the groove 29a and the protruding rib 5b is defined so that the tapered portion does not come off from the support hole 27a. In this figure, for the sake of convenience of explanation, only the back support protrusion 5d side is shown, but the same applies to the back support protrusion 5e side.

  FIG. 5 is a view showing a state of the back side when the laser scanner device 5 is mounted on the device main body (at a predetermined position).

  The back side support protrusions 5d and 5e are inserted into the support hole 27a by pushing up the back side biasing spring 32 when the laser scanner device 5 is inserted. At this time, the lower end of the rear support projections 5d and 5e is abutted against the lower end of the support hole 27a by the bias of the rear bias spring 32, and the vertical position of the rear side of the laser scanner device 5 is determined. Yes. Further, the back-side support protrusion 5e and the support hole 27a are fitted in the left-right direction with respect to the insertion direction, and are positioned in the left-right direction with respect to the back-side insertion direction of the laser scanner device 5.

  Here, the back side support protrusions 5d and 5e as the convex part, the support hole 27a as the concave part, and the back side biasing spring 32 as the first biasing means constitute a first positioning mechanism.

  FIG. 6 is a view for explaining the shape of the front scanner support member 28.

  28a is a positioning hole, 28b is an abutting portion as a first abutting portion, and 28c and 28d are spring engaging portions for applying a front side urging spring 37 as a second urging means described later.

  FIG. 7 is a diagram showing a state of the near side when the laser scanner device 5 is mounted on the apparatus main body (at a predetermined position).

When the laser scanner device 5 is inserted, the front side of the laser scanner device 5 is lifted slightly and then dropped to fit the positioning pin 5f into the positioning hole 28a. Thereby, positioning in the insertion direction of the laser scanner device 5 and positioning in the left-right direction with respect to the insertion direction on the front side of the laser scanner device 5 are performed. Here, the positioning pin 5f and the positioning hole 28a constitute a near-side positioning means.

  Further, the front side urging spring 37 is hooked on the upper surfaces of the spring hooking portions 28c and 28d and the front side support projection 5g as shown in the figure, so that the lower end portion of the front side support projection 5g is abutted against the second contact portion. The portion 28 b comes into contact with the urging force of the front urging spring 37. Thus, the front side of the laser scanner device 5 is positioned in the vertical direction.

  Here, the abutting portion 28b as the first abutting portion, the lower end portion of the near side support projection 5g as the second abutting portion, the near side biasing spring 37 as the second biasing means, and the near side positioning The positioning pins 5f and the positioning holes 28a as means constitute a second positioning mechanism.

  As described above, in this embodiment, the support members 27 and 28 are provided on the back side and the near side with respect to the insertion direction, and the laser scanner device 5 can be moved in the attachment / detachment direction while restricting the position in the left / right direction with respect to the insertion direction. One guide mechanism (guide rail 29 and protruding rib 5b) for guiding is provided. This guide mechanism guides the laser scanner device 5 to the back scanner support member 27 when the laser scanner device 5 is inserted.

  As a result, the laser scanner device 5 can be guided to a positioning mechanism on the back side of the apparatus main body that cannot be seen with a simple configuration, and a small and inexpensive image forming apparatus can be provided.

  Further, since the guide rail 29 is disposed at one end (one place) of the laser scanner device 5, the fitting portion of the laser scanner device 5 can be inserted into the entrance (insertion portion) of the guide rail 29. Visual observation can be ensured, and workability can be further improved.

  Further, in this embodiment, when the laser scanner device 5 is attached / detached, the position of the laser scanner device 5 in the vertical direction can be regulated, so that the laser scanner device 5 is dropped during the attaching / detaching operation of the laser scanner device 5. It is possible to prevent a situation such as turning or tilting. Thereby, it is possible to prevent the laser scanner device 5 from coming into contact with surrounding internal components during the attaching / detaching operation of the laser scanner device 5.

  In the present embodiment, the back side support protrusions 5d and 5e as the convex portions are provided in the laser scanner device 5 and the support hole 27a as the concave portion is provided in the back side scanner support member 27. However, the present invention is not limited thereto. It is not a thing. Any one of the laser scanner device 5 and the back scanner support member 27 may be provided with a convex portion and any of the other may be provided with a concave portion that fits into the convex portion.

  In this embodiment, the color image forming apparatus having the photosensitive drums 1Y, 1M, 1C, and 1K has been described. However, the present invention is not limited to this. That is, the present invention can be suitably applied to any image forming apparatus having at least one photosensitive drum.

  Hereinafter, the image forming apparatus of Example 2 will be described in detail with reference to FIGS. The schematic configuration of the image forming apparatus is the same as that of the first embodiment described above, and the same components are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 10 is a diagram illustrating an opening on the left side of the apparatus main body, an apparatus main body frame, and internal components of the apparatus main body. FIG. 11 is a diagram showing a state in which the laser scanner device 5 is inserted partway into the device main body.

  A feature of the present embodiment is that, in addition to the configuration of the first embodiment, an auxiliary receiving base 40 as an auxiliary receiving portion shown in FIGS.

  The auxiliary cradle 40 is disposed on the side opposite to the side where the guide rail 29 is provided with respect to the laser scanner device 5. Further, the auxiliary cradle 40 is provided at a position where the distance in the attaching / detaching direction from the near-side scanner support member 28 is at least half (L / 2) of the attaching / detaching length L of the laser scanner device 5.

  By providing the auxiliary cradle 40 in this way, when the laser scanner device 5 is inserted, when the center of gravity of the laser scanner device 5 passes through the front scanner support member 28, the side opposite to the guide rail 29 of the laser scanner device 5 is provided. You can catch the lower side of the lowering.

  With such a configuration, the backlash in the vertical direction of the laser scanner device 5 becomes smaller, and contact with each electric element of the low-voltage power supply device 31 can be avoided more reliably.

  In the present embodiment, the auxiliary cradle 40 is provided at a position where the distance from the front scanner support member 28 is at least half (L / 2 or more) of the insertion direction length L of the laser scanner device 5. This is not a limitation. If the auxiliary cradle 40 is provided on the side opposite to the side where the guide rail 29 is provided with respect to the laser scanner device 5, the vertical position of the laser scanner device 5 is effectively regulated. can do.

  In the first and second embodiments, the shape of the guide rail 29 and the laser scanner device 5 regulates the position in the left-right direction with respect to the insertion (removal) direction. A shape to be regulated may be added. For this, for example, the guide rail 29 as shown in FIG. 8 may be configured to further include an abutting portion that abuts on the upper end surface 5 b 3 of the protruding rib 5 b of the laser scanner device 5.

In Example 1, it is the schematic which shows the opening part of an apparatus main body left side, an apparatus main body frame, and an apparatus main body internal component. 1 is a schematic diagram illustrating a laser scanner device according to a first embodiment. In Example 1, it is the schematic which shows the state in which the laser scanner apparatus was inserted in the apparatus main body to the middle. In Example 1, it is the schematic which shows the mode of the back side in the middle of insertion of the laser scanner apparatus. In Example 1, it is the schematic which shows the mode of the back side when the laser scanner apparatus is mounted | worn in the predetermined position. In Example 1, it is the schematic explaining the shape of the near side scanner support member. In Example 1, it is the schematic which shows the mode of the near side when the laser scanner apparatus is mounted | worn in the predetermined position. In Example 1, it is a figure for demonstrating a guide mechanism. 1 is a schematic cross-sectional view showing an image forming apparatus to which the present invention can be applied. In Example 2, it is the schematic which shows the opening part of an apparatus main body left side, an apparatus main body frame, and an apparatus main body internal component. In Example 2, it is the schematic which shows the state in which the laser scanner apparatus was inserted in the apparatus main body to the middle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 5 Laser scanner apparatus 5b Projection rib 27 Back side scanner support member 28 Front side scanner support member 29 Guide rail 29a Groove part

Claims (7)

At least one image carrier;
An optical scanning unit that forms an electrostatic latent image on the image carrier by irradiating a laser beam in accordance with an image signal and scanning the image carrier;
In the image forming apparatus provided with the optical scanning unit detachably with respect to the image forming apparatus main body,
Two support members which are provided apart from the front side and the back side of the image forming apparatus main body with respect to the mounting direction of the optical scanning unit and support the optical scanning unit;
The optical scanning unit and the image forming apparatus main body are engaged with each other in the left-right direction of the optical scanning unit that is substantially perpendicular to the attaching / detaching direction, and the optical scanning unit moves in the attaching / detaching direction. One guide mechanism for guiding
With
The guide mechanism is provided so as to guide only one end side in the left-right direction of the optical scanning unit, and the optical scanning is performed with the image forming apparatus installed when the optical scanning unit is attached or detached. An image forming apparatus that restricts the position of the unit in the left-right direction. The support member on the near side is provided so as to regulate the position of the lower portion in the vertical direction of the optical scanning unit when the optical scanning unit is attached and detached.
Furthermore, an upper restricting member for restricting an upper part in the vertical direction of the optical scanning unit is provided on the front side of the image forming apparatus main body with respect to the attaching / detaching direction,
The guide mechanism has a vertical lower position restricting portion that restricts a position of a lower vertical direction of the optical scanning unit,
During the attaching / detaching operation of the optical scanning unit, the position of the optical scanning unit in the vertical direction is restricted by the lower position restricting portion of the guide mechanism, the support member on the near side, and the upper restricting member. The image forming apparatus according to claim 1.   A first positioning mechanism configured by engaging the back-side support member and the optical scanning unit to position the optical scanning unit with respect to the image forming apparatus main body, the front-side support member, and the optical The image forming apparatus according to claim 1, further comprising: a second positioning mechanism configured by engaging with a scanning unit and positioning the optical scanning unit with respect to the main body of the image forming apparatus. apparatus. The first positioning mechanism includes:
A convex portion provided in any one of the back-side support member and the optical scanning unit and protruding in the attaching / detaching direction;
A recess provided on the other of the support member on the back side and the optical scanning unit, and fitted into the projection;
A first biasing means for biasing the convex portion toward the concave portion when the convex portion and the concave portion are fitted;
The image forming apparatus according to claim 3, further comprising: In the second positioning mechanism,
A first contact portion provided on the front support member;
A second abutting portion provided in the optical scanning unit and abutting on the first abutting portion when the optical scanning unit is mounted on the image forming apparatus main body;
Second urging means for urging the second abutting portion against the first abutting portion so that the first abutting portion and the second abutting portion abut on each other;
A near-side positioning means for positioning in the attaching / detaching direction and the left-right direction when the optical scanning unit is mounted on the image forming apparatus main body;
The image forming apparatus according to claim 3, wherein the image forming apparatus includes:   The optical scanning unit includes an auxiliary receiving portion that is provided on the opposite side of the left-right direction from the side on which the guide mechanism is provided, and that receives a lower portion in the vertical direction of the optical scanning unit. Item 6. The image forming apparatus according to Item 5.   The length in the attachment / detachment direction from the support member on the near side to the auxiliary receiving portion is provided to be at least half the length in the attachment / detachment direction of the optical scanning unit. The image forming apparatus according to claim 6.

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