JP2019061138A - Image forming apparatus - Google Patents

Abstract

To provide a configuration in which a rotatable grip part is attached to a belt unit, and ensure the distance between the grip part and a belt while preventing an increase in size of the belt unit; to provide a belt unit to which a grip part can be attached with a small number of components.SOLUTION: A shaft rotatably supporting a grip part includes a large diameter part and a small diameter part; a through hole provided in the grip part includes a first hole part to which the small diameter part is fitted, and a second hole part communicated with the first hole part in a direction orthogonal to the axial direction and into which the large diameter part can be inserted. A projection part is formed between the first hole part and second hole part, and a gap formed by the projection part is smaller than the outer diameter of the small diameter part. The shaft includes a D-cut part smaller than the gap formed by the projection part, and when the D-cut part faces the gap, the shaft can move between the first hole part and second hole part. When the shaft is at an attachment position, the movement between the first hole part and second hole part of a shank is regulated by the projection part.SELECTED DRAWING: Figure 9

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile machine using an electrophotographic system or an electrostatic recording system.

  The image forming apparatus such as a printer or a copier is required to be small and highly functional, and accordingly, each unit in the apparatus is required to have a space-saving design. Meanwhile, in order to continue providing stable images to users, we regularly perform maintenance and replacement of each unit inside the device. Therefore, from the viewpoint of operability, the unit is provided with a handle member, and a user or a service person supports the handle member to carry the unit, which is easy to operate.

JP 2017-45014 A

  Conventionally, for example, Patent Document 1 proposes a configuration in which a handle member for gripping a belt unit is attached to a shaft member.

  As a structure which assembles a handle member to an axial member, what makes an axial member pass in a cylindrical hole with which a handle member was equipped can be considered. However, in the configuration in which the circumferentially transported belt member and the above-described shaft member are disposed close to each other in order to miniaturize the unit, the handle member provided on the shaft member may be in contact with the belt member. When the handle member and the belt member come in contact with each other, the belt member is scratched, and the toner image transferred at the scratched portion of the belt member is disturbed to cause an image defect. Therefore, it is desirable to separate the handle member and the belt member as much as possible. In order to reduce the distance between the handle member and the belt member, the shaft diameter of the shaft member may be reduced as much as possible while ensuring the minimum thickness of the handle member. However, if the diameter of the entire shaft member is reduced, the strength of the shaft member is reduced and the shaft member is bent. Therefore, it is conceivable to reduce the diameter of only the region where the handle member is attached and attach the handle member to the small diameter portion. Thus, when the structure which inserts the axial member from which an axial diameter differs in the handle member is employ | adopted, the following shapes can be considered as a through-hole which makes a handle member pass an axial member. First, a hole for the large diameter portion for inserting the large diameter portion of the shaft member is provided. Then, after the small diameter portion of the shaft member is inserted into the through hole of the handle member, it is conceivable to provide a hole portion for the small diameter portion to be fitted with the small diameter portion of the shaft member. At this time, a fixing member for fixing the shaft member to the handle member is required so that the small diameter portion of the shaft member is not detached from the hole for the small diameter portion. Therefore, there is a problem that the number of parts increases.

  In view of the foregoing, it is an object of the present invention to provide an image forming apparatus in which a handle can be attached with a small number of parts while suppressing an increase in size in an image forming apparatus in which the handle is attached to a shaft member provided in a belt unit. It is.

  The image forming apparatus according to the present invention comprises: an image carrier for carrying an image; a belt unit detachably mounted on the apparatus main body; and a belt to which a toner image carried by the image carrier is transferred; And a handle portion for gripping the belt unit when taking out the belt unit from the apparatus main body, and the belt unit being inserted into the through hole provided in the handle portion. An image forming apparatus comprising: a shaft rotatably supporting the handle portion, wherein the shaft includes a first shaft portion and a second shaft portion thicker than the first shaft portion. The through hole is provided at a position different from the first hole portion with respect to the first hole portion to which the first shaft portion can be fitted and the direction orthogonal to the axial direction of the shaft; A second hole into which the second shaft can be inserted, and the first hole And a communicating portion for communicating the second hole portion, the handle portion being provided at a position facing the first shaft portion when the handle portion is mounted on the belt unit, and a gap of the communicating portion is provided The projection is provided so as to project from the inner surface of the through hole so as to be narrower than the outer diameter of the first shaft, and the axis has a thickness in a predetermined direction orthogonal to the axial direction of the axis. And the shaft is in communication when the third shaft portion is smaller than the third shaft portion and the axial length of the shaft is longer than the protrusion, and the third shaft portion is at a position facing the protrusion. It is characterized in that it is configured to be able to pass through the unit.

  According to the present invention, it is possible to provide an image forming apparatus capable of attaching a handle member with a small number of parts while suppressing an increase in size, in an image forming apparatus for attaching a handle member to a shaft member provided in a belt unit. it can.

Schematic cross-sectional view of the image forming apparatus Schematic cross-sectional view of the intermediate transfer belt unit at the time of image formation Schematic cross-sectional view of the intermediate transfer belt unit in the first state Schematic cross-sectional view of the intermediate transfer belt unit in the second state Schematic perspective view of the state when carrying the intermediate transfer belt unit Schematic perspective view around the handle member of the intermediate transfer belt unit Schematic perspective view of the handle member Schematic cross-sectional view of the D-cut area A schematic perspective view and a schematic cross-sectional view in the vicinity of the shaft member and the handle member Schematic perspective view and schematic cross-sectional view at the time of handle member assembly Schematic perspective view of the handle member (Example 2) A schematic perspective view and a schematic sectional view at the time of assembling the handle member (Example 2) Schematic perspective view of the handle member (conventional configuration) A schematic perspective view and a schematic cross-sectional view in the vicinity of the shaft member and the handle member (conventional structure) A schematic perspective view and a schematic sectional view at the time of assembling a handle member (conventional example)

Example 1
Hereinafter, preferred embodiments of the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified. .

<Overall Configuration and Operation of Image Forming Apparatus>
FIG. 1 is a schematic cross-sectional view of an intermediate transfer type tandem color digital printer having four image forming sections as an image forming apparatus 100 to which the present invention is applied, viewed from the front. First, an outline of the image forming apparatus 100 will be described.

  The image forming apparatus 100 is provided with an intermediate transfer belt unit 10 in which the intermediate transfer belt 17 is stretched and supported at the middle position. Further, under the intermediate transfer belt unit 10, image forming portions 106a to 106d for forming yellow, magenta, cyan and black toner images on the intermediate transfer belt 17 are provided. The image forming units 106a to 106d are provided with photosensitive drums 101a to 101d as image bearing members, and the surfaces thereof are uniformly charged by the charging rollers 102a to 102d. Image signals of yellow, magenta, cyan, and black are input to the laser scanners 103a to 103d, respectively, and the surfaces of the photosensitive drums 101a to 101d are irradiated with laser light according to the image signals to neutralize charges and to electrostatic Form a latent image. The electrostatic latent images are manifested as toner images of respective colors by the developing devices 104a to 104d, respectively, and then primary-transferred to the intermediate transfer belt 17 in order to form a full-color toner image on the intermediate transfer belt 17. The toner agents remaining on the photosensitive drums 101a to 101d are collected by the drum cleaners 105a to 105d.

  On the other hand, a transfer material P such as paper fed from any of the feeding units 111 and 112 or the manual feeding unit 113 is registered one by one via the feed roller 110, the feed roller 114 and the retard roller 115. It is sent to the pair 116. When the front end of the transfer material P abuts against the stopped registration roller, a loop is formed, and the registration roller starts to rotate in synchronization with the toner image on the intermediate transfer belt 17.

  The toner image on the intermediate transfer belt 17 is transferred to a transfer material P by a secondary transfer portion 107 formed by a secondary transfer outer roller 108 and the intermediate transfer belt 17, and fixed by heat and pressure in a fixing device 109. Thereafter, the transfer material P is discharged from the paper discharge unit 117a or 117b to the paper discharge trays 118a and 118b outside the apparatus. Further, the toner agent which is not transferred at the secondary transfer portion 107 and remains on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaner 50.

<Intermediate transfer belt unit>
Next, the intermediate transfer belt unit 10 will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view of the intermediate transfer belt unit 10 at the time of full color image formation. FIG. 3 is a schematic cross-sectional view of the intermediate transfer belt unit 10 at the time of monochrome image formation (first state). FIG. 4 is a schematic cross-sectional view of the intermediate transfer belt unit 10 in the second state, which is positioned during maintenance such as belt replacement. FIG. 5 is a schematic perspective view showing a state when carrying the intermediate transfer belt unit 10, and FIG. 6 is a schematic perspective view showing the configuration around the handle member of the intermediate transfer belt unit 10. As shown in FIG.

  As shown in FIGS. 2 to 4, the intermediate transfer belt 17 made of polyimide or the like is stretched by five rollers of the secondary transfer inner roller 11, the steering roller 12, the tension roller 13, the auxiliary roller 14 and the idler roller 15. It is done. The rollers 11 to 15 are rotatably supported at both ends by bearings (not shown). In the present embodiment, the steering roller 12 also has a function as a drive roller, and the same reference numerals are given and described. However, the steering roller 12 does not necessarily have to be a drive roller, and it is also effective when, for example, the idler roller 15 or the secondary transfer inner roller 11 is a drive roller in FIG.

  The surface of the drive roller 12 is formed of a rubber layer having a high coefficient of friction in order to transport the intermediate transfer belt 17 without slipping. Further, the intermediate transfer belt 17 is applied with a tension by being pressed from the inner surface of the belt by the tension roller 13. The intermediate transfer belt 17 is circularly conveyed counterclockwise (see an arrow 200 in FIG. 2) by the steering roller 12 also serving as a driving roller being rotationally driven.

  The primary transfer rollers 16a to 16d are disposed between the idler roller 15 for supporting the intermediate transfer belt 17 and the auxiliary roller 14 at positions facing the photosensitive drums 101a to 101d of the respective colors. The primary transfer rollers 16a to 16d are rotatably supported at their respective ends by bearings (not shown), and press the intermediate transfer belt 22 from the inner surface by elastic members (not shown). Thus, the intermediate transfer belt 17 is nipped by the primary transfer rollers 16a to 16d and the photosensitive drums 101a to 101d (see FIG. 2).

<Separation mechanism of photosensitive drum>
The intermediate transfer belt unit 10 is configured to be switchable between a first state in which the intermediate transfer belt 17 contacts at least one photosensitive drum and a second state in which the intermediate transfer belt 17 and all the photosensitive drums are separated. Be done. The switching between the first state and the second state is performed by rotation of a shaft member 20 rotatably provided to the intermediate transfer belt unit 10. That is, when the shaft member 20 rotates, the intermediate transfer belt 17 and the photosensitive drum can be brought into contact with and separated from each other. In the present embodiment, the rotation of the shaft member 20 is configured such that switching of the first state to the second state is performed when the operator turns the lever fixed to the shaft member 20. In addition, although the case where it switches from a 1st state to a 2nd state was demonstrated in this embodiment, it is not limited to this. For example, as shown in FIG. 2, the shaft member 20 can be used to switch the state in which the photosensitive drums 101 of each color are in contact with the intermediate transfer belt 17 (all contact state) to the second state. The operation of switching between the first state and the second state of the intermediate transfer belt unit 10 will be described in more detail below. The intermediate transfer belt unit 10 is provided with a support shaft 27 substantially parallel to the axial direction of the stretching roller on the left outer side of the yellow primary transfer roller 16a disposed at the left end when viewed from the front of the image forming apparatus. The storage shaft 28 of the support member 28 provided in the frame unit 18 is engaged with the support shaft 27, and the frame unit 18 can be pivoted about the support shaft 27 via the support member 28. Further, in the intermediate transfer belt unit 10, the shaft member 20 is rotatably supported in the vicinity of both end portions substantially parallel to the axial direction of the stretching roller, and the moving member 25 is further adjacent to the both end portions. It is fixed. The moving member 25 is provided with a guide groove 25a, and the guide groove 25a has a curved surface shape, and is a cam whose distance from the shaft member 20 gradually changes according to the rotation angle of the moving member 25. On the other hand, on both sides of the front and back sides of the belt frame unit 18 when viewed from the front of the image forming apparatus, guide shafts 26 projecting outward are provided, and the guide shafts 26 engage with the guide grooves 25a. (See Figure 3). In the first state of the intermediate transfer belt unit 10, when the shaft member 20 is turned counterclockwise as viewed from the front of the image forming apparatus, the moving member 25 and the guide groove 25a rotate the shaft member 20 in conjunction therewith. It turns counterclockwise around the movement center. At this time, the guide shaft 26 of the frame unit 18 is engaged with the guide groove 25a, and the guide shaft 26 moves upward substantially in the direction of gravity while contacting the curved surface of the guide groove 25a by rotation of the shaft member 20. As a result, the frame unit 18 pivots counterclockwise about the support shaft 27 via the movement of the guide shaft 26. When the pivoting operation of the shaft member 20 is completed, the intermediate transfer belt 17 provided in the frame unit 18 and all the photosensitive drums 101a to 101d are separated, and the intermediate transfer belt unit 10 is in the second state (see FIG. 4). ).

  The intermediate transfer belt unit 10 is configured to be removable from the apparatus main body when in a second state in which the intermediate transfer belt 17 and all the photosensitive drums are separated. When the intermediate transfer belt unit 10 is in the second state, the distance between the intermediate transfer belt 17 and the components provided below the photosensitive drums 101a to 101d and in the direction of gravity of the intermediate transfer belt unit 10 is secured. For this reason, workability is good when attaching and detaching the intermediate transfer belt unit 10 from the main body of the image forming apparatus. The mounting and demounting direction of the intermediate transfer unit 10 with respect to the main body portion of the image forming apparatus in the present embodiment is the drawing direction toward the front side when viewed from the front of the image forming apparatus. That is, the intermediate transfer belt unit 10 is removable through an opening provided on the side surface orthogonal to the axial direction of the photosensitive drums 101a to 101d. After the intermediate transfer belt unit 10 is pulled out of the main body of the image forming apparatus, the handle member 21 and the handle 19 provided on the intermediate transfer belt unit 10 are supported to facilitate carrying of the intermediate transfer belt unit 10 See Figure 5).

<Handle member of belt unit>
As shown in FIG. 5, the handle portion 19 is disposed above the intermediate transfer belt 17 in the vertical direction. The handle portion 19 is provided at a position overlapping the intermediate transfer belt 17 when viewed in a direction orthogonal to the axial direction of the shaft member 20. The handle member 21 is provided on the shaft member 20 so as to be rotatable about the shaft member 20 as a rotation center. The shaft member 20 is provided with a first shaft portion 20a at a position where the shaft member 20 and the handle member 21 engage, and a second shaft portion 20b at other positions. That is, the shaft member 20 has the first shaft portion 20 a positioned inside the through hole when the handle member 21 is attached to the intermediate transfer belt unit 10. The shaft member 20 also has a second shaft portion 20b positioned outside the through hole when the handle member 21 is attached to the intermediate transfer belt unit 10. The outer diameter of the first shaft portion 20a is smaller than that of the second shaft portion 20b. Therefore, the outer shape of the handle member 21 engaged with the first shaft portion 20a can be miniaturized. The detailed configuration of the radial positioning of the handle member 21 with respect to the first shaft portion 20a will be described later. Further, the intermediate transfer belt unit 10 is provided with a frame member 23 for rotatably supporting both end portions of the shaft member 20, and the frame member 23 is provided with a storage portion 23a capable of storing the handle member 21. The position of the handle member 21 in the axial direction of the shaft member 20 is regulated by contact between the position regulating portions 23 b and 23 c provided in the storage portion 23 a and the side portions 21 d and 21 e of the handle member 21. The elastic member 24 is engaged with the shaft member 20, and the handle member 21 is elastically urged by the elastic member 24 in the direction (the circumferential direction of the shaft member 20) stored in the storage portion 23a (see FIG. 6). Thus, when carrying the intermediate transfer belt unit 10, the handle member 21 is lifted against the elastic force of the elastic member 24 with the shaft member 20 as the rotation center. Otherwise, the handle member 21 is always stored in the storage portion 23a, so the intermediate transfer belt unit 10 can be miniaturized.

<Assembly and positioning of handle members>
Next, the assembly of the handle member 21 with respect to the shaft member 20 and the positioning in the radial direction in the configuration of the present embodiment will be described using FIGS. FIG. 7 is a schematic perspective view of the handle member. FIG. 8 is a schematic perspective view of the periphery of the D-cut portion 20 d of the shaft member 20.

  FIG. 9A is a schematic perspective view of a state in which the handle member 21 is assembled to the shaft member 20. FIG. FIG.9 (b) is a schematic sectional drawing showing the cross section of the surface parallel to the plane part 20c in the state of Fig.9 (a). FIG.9 (c) is a schematic sectional drawing of the handle member 21 engaging part in the state of Fig.9 (a).

  Fig.10 (a-1) is a schematic perspective view showing a mode that the 2nd axial part 20b passes in the 2nd through-hole 21b in the assembly in this embodiment. Fig.10 (a-2) is a schematic sectional drawing showing the cross section of the surface parallel to the plane part 20c in the state of Fig.10 (a-1).

  FIG. 10 (b-1) is a schematic perspective view of a state in which the D-cut portion 20d (see FIG. 8) of the first shaft portion 20a and the protrusion 21c face each other. FIG.10 (b-2) is a schematic sectional drawing showing the cross section of the surface parallel to the plane part 20c in the state of FIG.10 (b-1).

  FIG. 10C-1 is a schematic perspective view showing a state in which the first shaft portion 20a is moved to the first through hole 21a. FIG.10 (c-2) is a schematic sectional drawing showing the cross section of the surface parallel to the plane part 20c in the state of FIG.10 (c-1). FIG.10 (c-3) is a schematic sectional drawing of the handle member 21 engaging part in the state of FIG.10 (c-1).

  The shaft member 20 is provided with a first shaft portion 20a at a position where the handle member 21 is engaged in the axial direction of the shaft member 20, and a second shaft portion 20b at another position outside the engaged position. The outer diameter of the first shaft portion 20a is smaller than the outer diameter of the second shaft portion 20b. Further, the first shaft portion 20a is provided with a D-cut portion 20d including the flat portion 20c. The D-cut portion 20d has a thickness in a predetermined direction smaller than the diameter of the first shaft portion 20a. The D-cut portion 20 d has an arc portion centering on the axis of the shaft member 20 and a flat portion 20 c parallel to the axis of the shaft member 20. The handle member 21 is provided with a through hole in the axial direction of the shaft member 20, and the shaft member 20 is configured to be insertable. In the through hole, a first through hole 21a (first hole) that can be fitted to the first shaft 20a of the shaft member 20 when the handle member 21 is mounted, and a second shaft 20b are provided. It has a second through hole 21b (second hole) which can pass through. The first through hole 21 a and the second through hole 21 b communicate with each other in the direction orthogonal to the axial direction of the shaft member 20. That is, the communication part is formed between the first through hole 21a and the second through hole 21b. A protrusion 21 c is provided between the first through hole 21 a and the second through hole 21 b. The through hole surrounded by the first through hole 21 a and the projection 21 c has a size in which the first shaft 20 a fits.

  That is, in the present embodiment, between the first through hole 21a and the second through hole 21b, the inner surface of the through hole has a protrusion 21c projecting from the inner surface of the through hole so that the gap between the through holes is narrow. It is formed.

  The protrusion 21c has a width smaller in the axial direction of the shaft member 20 than the groove width of the D-cut portion 20d (the axial length of the flat surface 20c). The distance of the gap H1 formed by the first through hole 21a and the projection 21c is larger than the thickness H2 of the flat portion 20c and the outer diameter portion of the first shaft portion 20a (FIGS. 7 to 7). 9).

  Further, the distance of the gap H1 formed by the first through hole 21a and the projection 21c is smaller than the outer diameter of the first shaft 20a. Here, if the distance of the gap H1 is too wide, after the handle member 21 is attached to the shaft member 20, the shaft member 20 is detached to the second through hole 21b side. On the other hand, if the distance of the gap H1 is too narrow, the thickness H2 of the D-cut portion 20d becomes too small. Therefore, in the present embodiment, the distance of the gap H1 is between the outer diameter of 1 mm of the first shaft portion 20a and the outer diameter x 60% of the first shaft portion 20a. Preferably, the distance of the gap H1 is between the outer diameter -1.5 mm of the first shaft portion 20a and the outer diameter -2.5 mm of the first shaft portion 20a. In other words, the difference between the distance of the gap H1 and the outer diameter of the first shaft portion 20a is preferably greater than 1 mm and less than 40 of the outer diameter of the first shaft portion 20a. Further, the difference between the distance of the gap H1 and the outer diameter of the first shaft portion 20a is more than 1.5 mm, and more preferably less than 2.5 mm.

  Next, assembly of the shaft member 20 and the handle member 21 will be described. First, the second shaft portion 20 b of the shaft member 20 is axially passed through the second through hole 21 b of the handle member 21. The direction of passage of the shaft member 20 in the present embodiment is a direction from the back to the front as viewed from the front of the image forming apparatus (see FIG. 10A). When the second shaft 20b is axially passed through the second through hole 21b, the D-cut 20d of the first shaft 20a and the projection 21c face each other (see FIG. 10B). From this state, in the first shaft portion 20a, the thickness H2 of the flat surface portion 20c and the outer diameter portion of the first shaft portion 20a passes through the gap H1 formed by the first through hole 21a and the projection portion 21c. , And moves from the second through hole 21b to the first through hole 21a (see FIG. 10 (c)). After the first shaft portion 20a is moved into the first through hole 21a, the first shaft portion 20a is further passed through the first through hole 21a in the axial direction of the shaft member 20. The direction of the passage is a direction from the back to the front as viewed from the front of the image forming apparatus. When the first shaft portion 20a is passed through the first through hole 21a in the axial direction of the shaft member 20 and the D cut portion 20c and the protrusion 21c are not at the opposite position, the first shaft portion 20a is It will be in the state fitted to the through hole enclosed by the through hole 21a and the projection part 20c. Thereby, the handle member 21 is positioned in the radial direction with respect to the shaft member 20, and it becomes possible to turn the shaft member 20 about the rotation center (see FIG. 9).

  Further, in the present embodiment, the direction in which the second shaft portion 20b passes through in the second through hole 21b and the direction in which the first shaft portion 20a passes through in the first through hole 21a are the same. If the above passing directions are not the same, the amount of movement for causing the second shaft portion 20b to pass through in the second through hole 21b is larger than when it is the same. When the amount of movement of the shaft member 20 increases, the arrangement of other components assembled to the intermediate transfer belt unit 10 is restricted, resulting in a complicated and large-sized apparatus. In the present embodiment, by making the above passing method the same, the complication and the enlargement of the device are suppressed.

  Here, the positional relationship among the first through hole 21a, the second through hole 21b, and the intermediate transfer belt 17 provided in the handle member 21 in the present embodiment will be described. In the present embodiment, when the handle member 21 and the shaft member 20 are fitted and supported by the first through hole 21 a, the distance between the handle member 21 and the intermediate transfer belt 17 is set to a first distance. The first distance is larger than the second distance between the handle member 21 and the intermediate transfer belt 17 when the handle member 21 and the shaft member 20 (second shaft portion 20b) are fitted in the second through hole 21b. It is a relationship. Therefore, by fitting the first shaft portion 20a and the first through hole 21a, the distance between the handle member 21 and the intermediate transfer belt 17 can be increased, and the enlargement of the apparatus can be suppressed.

  Specifically, in the present embodiment, when the handle member 21 is stored in the storage portion 23a, the positional relationship between the first through hole 21a and the second through hole 21b with respect to the intermediate transfer belt 17 is set as follows. ing. That is, the intermediate transfer belt 17 is disposed below the shaft member 20 in the vertical direction. Further, the lowermost position of the first through hole 21a when the handle member 21 is stored in the storage portion 23a and the lowermost position of the second through hole 21b are set at substantially the same height. Thus, the distance between the handle 21 and the intermediate transfer belt 17 when the handle 21 is attached can be increased by the difference between the diameters of the first shaft 20a and the second shaft 20b. In the present embodiment, the height of the lowest point of the first through hole 21a when the handle member 21 is stored in the storage portion 23a is the same as the height of the lowest point of the second through hole 21b. However, it is not limited to this. If the intermediate transfer belt is positioned downward as in this embodiment, the lowermost position of the first through hole 21a is lower or upper than the lowermost position of the second through hole 21b. May be When the lowest point position of the first through hole 21a is located above the lowest point position of the second through hole 21b, the height difference between the lowest point positions is the first shaft portion 20a and the second shaft portion 20a The difference is set equal to or less than the difference in shaft diameter of the shaft portion 20b. In this way, the effect of increasing the distance between the handle member 21 and the intermediate transfer belt 17 can be obtained. Further, in the present embodiment, although the case where the intermediate transfer belt 17 is disposed below the shaft member 20 has been described as an example, the present invention is not limited to this. The closest distance between the first through hole 21a and the intermediate transfer belt 17 when the handle member 21 is stored in the storage portion 23a is L1. The closest distance between the second through hole 21b and the intermediate transfer belt 17 is L2. Further, the difference between the shaft diameters of the first shaft portion 20a and the second shaft portion 20b is L3. At this time, if L1 <L2 + L3 is satisfied, the distance between the handle member 21 and the intermediate transfer belt 17 can be increased.

  Further, in the present embodiment, when carrying the intermediate transfer belt unit 10, the shaft member 20 has a rotational phase in which the flat portion 20c is substantially parallel to the gravity direction. That is, when the phase of the shaft member 20 is a phase corresponding to the second state (the state in which the intermediate transfer belt 17 and all the photosensitive drums are separated), the angle between the plane portion 20c and the gravity direction is within 20 °. It is set to. That is, when the phase of the shaft member 20 is the phase when the intermediate transfer belt unit 10 can be detached from the apparatus main body, the angle between the plane portion 20c and the direction of gravity is set within 20 °. More preferably, when the phase of the shaft member 20 is the phase when the intermediate transfer belt unit 10 can be detached from the apparatus main body, the angle between the plane portion 20c and the direction of gravity is set within 10 °. . The load due to the weight of the intermediate transfer unit 10 applied to the shaft member 20 via the handle member 21 is substantially upward in the direction of gravity. As a result, the second moment of area to bending of the portion where load is applied to the shaft member 20 becomes relatively large, and the decrease in the allowance for deformation and breakage is suppressed.

  According to the present embodiment, the shaft member 20 and the handle member are disposed at positions where the protrusions 21c provided in the through holes of the handle member 21 and the D cut portions 20d provided on the shaft member 20 are shifted in the axial direction. 21 is assembled. By doing this, it is possible to suppress that the shaft member 20 is detached from the first through hole 21a and moved to the second through hole 21b after the handle member 21 is attached. In addition, in order to prevent the shaft member 20 from moving out of the first through hole 21a to the second through hole 21b, no additional parts are required, and thus an increase in the number of parts can be suppressed. it can.

<Reference example>
Here, as a reference example, a fixing member is separately provided so that the fitting between the first shaft portion 20a and the first through hole 21a is not removed, and the configuration for performing the thrust positioning of the handle member is shown in FIGS. Use and explain. FIG. 13 is a schematic perspective view of the handle member 221. As shown in FIG. FIG. 14A is a schematic perspective view of a state in which the handle member 221 is attached to the shaft member 220. FIG. FIG. 8 (b) is a schematic cross-sectional view of the engaging portion of the handle member 221 in the state of FIG. 14 (a). FIG. 15A is a schematic perspective view showing a state in which the second shaft portion 220 b passes through the second through hole 221 b in assembly. FIG. 15B is a schematic perspective view showing a state in which the first shaft portion 220a passes through the second through hole 221b. FIG. 15C is a schematic perspective view showing a state in which the first shaft portion 220a is moved to the first through hole 221a and the fixing member 222 is assembled.

  The shaft member 220 includes a first shaft portion 220a at a position where the handle member 221 engages in the axial direction of the shaft member 220, and a second shaft portion 220b at other positions, and the outer diameter of the first shaft portion 220a Is smaller than the outer diameter of the second shaft portion 220b. The handle member 221 is provided with a through hole through which the shaft member 220 passes, and the through hole has a first through hole 221 a and a second shaft portion 220 b having a width fitted to the first shaft portion 220 a of the shaft member 220. Is provided with a second through hole 221 b through which The first through hole 221a and the second through hole 221b are connected such that the first shaft 220a can move between them. Furthermore, the handle member 221 is provided with fixing member engaging portions 221c and 221d with which the fixing member 222 is engaged. In a state in which the fixing member 222 is engaged with the handle member 221, the first through hole 221a and the second through hole 221b are partitioned by the fixing member 222 and surrounded by the first through hole 221a and the fixing member 222. The through hole has a size in which the first shaft 220a is fitted (see FIGS. 13 and 14).

  Next, assembly of the shaft member 220 and the handle member 221 will be described. First, the second shaft portion 220b of the shaft member 220 is axially passed through the second through hole 221b of the handle member 221 (see FIG. 15A). When the second shaft portion 220b is axially passed through the second through hole 221b, the first shaft portion 220a passes through the second through hole 221b (see FIG. 15B). In a state where the first shaft portion 220a passes through the second through hole 221b, the first shaft portion 220a moves from the second through hole 221b to the first through hole 221a. Here, when the fixing member 222 is assembled to the fixing member engaging portions 221c and 221d of the handle member 221, the first shaft portion 220a is fitted in the through hole surrounded by the first through hole 221a and the fixing member 222. It will be in the state to match (refer FIG. 14, FIG.15 (c)). Thereby, the handle member 221 is positioned in the radial direction with respect to the shaft member 220, and it becomes possible to turn the shaft member 220 about the rotation center. In addition, the outer diameter of the handle member 221 can be reduced by the difference in outer diameter between the first shaft portion 220a and the second shaft portion 220b, and the handle member 221 can be separated from the belt member. And operability can be combined.

  However, in the above-described configuration, in addition to the shaft member 220 and the handle member 221, the fixing member 222 for positioning is required, and there is a problem that the number of parts is increased and the cost is increased.

Example 2
The shape of the through hole of the handle member 21 is different from that of the first embodiment. The present embodiment improves the assemblability of the handle member 21 with respect to the shaft member 20 in the first embodiment. The configuration of the present embodiment will be described in detail using FIGS.

  FIG. 11 is a schematic perspective view of the handle member 21 in the present embodiment. FIG. 12 (a) is a schematic perspective view showing a state in which the first shaft portion 20a is moved to the first through hole 21a, and FIG. 12 (b) is an engagement of the handle member 21 in the state of FIG. It is a schematic sectional view of a part.

  The handle member 21 is provided with a through hole in the axial direction of the shaft member 20, and the through hole has a first through hole 21a (first through hole) with a width fitted to the first shaft portion 20a of the shaft member 20. It has a second through hole 21b (second shape portion) through which the second shaft portion 20b can pass. A protrusion 21 c is provided between the first through hole 21 a and the second through hole 21 b. The through hole surrounded by the first through hole 21 a and the projection 21 c has a size in which the first shaft 20 a fits.

  The protrusion 21 c has a width smaller in the axial direction of the shaft member 20 than the groove width of the D-cut portion 20 d. The protrusion 21f is provided on the opposite surface side of the protrusion 21c, and the distance between the protrusion 21c and the gap H3 formed by the protrusion 21f is the thickness of the flat portion 20c and the outer diameter portion of the first shaft portion 20a. The relationship is smaller than H2 (see FIG. 11).

  In assembling the handle member 21 to the shaft member 20, when the first shaft portion 20a is moved from the second through hole 21b to the first through hole 21a, the D cut portion 20d is formed by the projection 21c and the projection 21f. It passes through the formed gap H3. Therefore, the first shaft portion 20a is temporarily fixed by the projection 21f in the first through hole 21a. Thereby, it is suppressed that the 1st axial part 20a moves in the direction which returns to the 2nd penetration hole 21b from the 1st penetration hole 21a. Therefore, when passing the first shaft portion 20a with respect to the first through hole 21a which is the next assembling operation, the side surface portion formed orthogonal to the flat portion 21c of the D cut portion 21d is the protrusion 21c. It can be abutted against the side surface of the body to be an obstacle to work. This improves the workability (see FIG. 12).

  In this embodiment, the distance of the gap H1 formed by the first through hole 21a and the projection 21c is larger than the thickness H2 of the flat portion 20c and the outer diameter portion of the first shaft portion 20a. In the example described above, the present invention is not limited to this. Even if the gap H1 is smaller than the thickness H2, the D cut portion 21d may be in a range in which the gap H1 can be moved. For example, if the difference between the gap H1 and the thickness H2 is 1 mm or less, the D-cut portion 21d can move the gap H1.

  In the present embodiment, although the cross sections of the first shaft portion 20a and the second shaft portion are both described as an example of a circle, it is not necessarily limited to this. For example, the cross section orthogonal to the axis may be elliptical.

10 Intermediate Transfer Belt Unit 11 Secondary Transfer Inner Roller 12 Steering Roller (Drive Roller)
13 tension roller 14 auxiliary roller 15 idler roller 16a to 16d primary transfer roller 17 intermediate transfer belt 20 shaft member 20a first shaft portion 20b second shaft portion 20c flat portion 20d D cut portion 21 grip member 21a first penetration Hole 21b Second through hole 21c Protrusion 21d, 21e Side surface 21f Projection 100 Image forming apparatus 200 Belt circumferential direction 220 Shaft member 220a First shaft 220b Second shaft 221 Handle member 221a First through hole 221b Second through hole 221c Fixing member engaging portion 221d Fixing member engaging portion 222 Fixing member H1 Clearance H2 between the first through hole and the protrusion 21c H2 Thickness between the flat portion and the outer diameter portion of the first shaft portion H3 A gap formed by the protrusion 21c and the protrusion 21f

Claims (8)

An image carrier for carrying an image;
A belt unit provided detachably on the apparatus main body and including a belt to which a toner image carried by the image carrier is transferred;
A handle portion provided rotatably on the belt unit and for gripping the belt unit when removing the belt unit from the apparatus main body;
An image forming apparatus comprising: a shaft provided in the belt unit and inserted into a through hole provided in the handle to rotatably support the handle;
The shaft comprises a first shaft portion and a second shaft portion thicker than the first shaft portion,
The through hole is provided at a position different from the first hole portion with respect to a direction perpendicular to the axial direction of the axis, with the first hole portion to which the first shaft portion can be fitted, and the second axis A second hole portion into which the portion can be inserted, and a communication portion connecting the first hole portion and the second hole portion,
The handle portion is provided at a position facing the first shaft portion when mounted on the belt unit, and the gap of the communication portion is narrower than the outer diameter of the first shaft portion. A projection which protrudes from the inner surface of the through hole;
The shaft has a third shaft portion whose thickness in a predetermined direction orthogonal to the axial direction of the shaft is smaller than that of the first shaft portion, and the axial length of the shaft is longer than the protrusion. The shaft is configured to be able to pass through the communication portion when the third shaft portion is at a position facing the protrusion.
An image forming apparatus characterized by   The difference between the clearance formed in the communication portion by the projection and the shaft diameter of the first shaft portion is larger than 1.5 mm and smaller than 2.5 mm. Image forming apparatus as described.   The image forming apparatus according to claim 1, wherein a gap H <b> 1 formed in the communication portion by the protrusion is larger than a thickness H <b> 2 of the third shaft portion in the predetermined direction.   The belt and the image carrier are configured to be in contact with and separated from each other by the rotation of the shaft, and the third shaft portion is a flat portion parallel to the axial direction of the shaft, and the axis of the shaft. When the phase of the shaft is such that the belt unit can be detached from the apparatus main body, the angle between the plane portion and the direction of gravity is within 20 °. The image forming apparatus according to any one of claims 1 to 3, wherein   5. The image forming apparatus according to claim 1, further comprising an opening provided on a side surface orthogonal to the axial direction of the image carrier, wherein the belt unit is detachably attached to the apparatus main body through the opening. An image forming apparatus according to any one of the above.   6. The grip according to any one of claims 1 to 5, wherein the handle portion is provided at a position overlapping the belt when viewed vertically from the belt and in a direction perpendicular to the axial direction of the shaft. The image forming apparatus according to claim 1.   In the cross section orthogonal to the axial direction, the closest distance between the first hole and the belt is L1, the closest distance between the second hole and the belt is L2, and the first shaft and The image forming apparatus according to any one of claims 1 to 6, wherein L1 <L2 + L3 is satisfied, where L3 is a difference between the outer diameters of the second shaft portions.   The first shaft portion and the third shaft portion are provided at positions sandwiched by the second shaft portions in the axial direction of the shaft. The image forming apparatus according to claim 1.

Images