JP2010152245A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of easily taking out a belt unit even in the case an obstructive structure is disposed around the belt unit. <P>SOLUTION: The image forming apparatus (color printer 1) includes a drawer 8 for supporting a plurality of process cartridges 5 having a photosensitive drum 51 drawably from an apparatus body 10. An extrusion mechanism 9 for pushing up a belt unit 6 is provided in the apparatus body 10. A handle part 64A of the belt unit 6 is revealed by pushing up the belt unit 6 in the space A in the apparatus body 10 formed by drawing out the drawer 8. The belt unit 6 may be taken out from an opening part 10A of the apparatus body 10 by the handle part 64A. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a belt unit facing a plurality of photosensitive drums.

  2. Description of the Related Art Conventionally, a plurality of process cartridges having photosensitive drums, a belt unit having a belt for conveying paper between the photosensitive drums, a paper feeding unit (supply unit) for supplying paper to the belt units, and a process cartridge are provided. An image forming apparatus including a front cover that opens and closes an opening for attaching to and detaching from a main body is known (see Patent Document 1). In this technology, the paper feed unit is arranged between the front cover and the belt unit. However, since the paper feed unit is fixed to the front cover, the paper feed unit is separated from the belt unit when the front cover is opened. The belt unit is exposed to the outside. Thereby, in order to perform maintenance (replacement, cleaning, etc.) of the belt unit, an operator can grasp the belt unit and take it out from the apparatus main body.

JP 2007-57953 A

  However, the conventional technique has a problem in that the paper feed unit is fixed to the front cover, which makes the front cover heavy and difficult to operate. Further, in order to solve this problem, when the paper feeding unit is fixed to the main body, there is a problem that it becomes difficult to take out the belt unit because the paper feeding unit located in front becomes an obstacle.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus in which a belt unit can be easily taken out even when a disturbing structure is disposed around the belt unit.

  The present invention that solves the above problems is an image forming apparatus that includes a plurality of photosensitive drums, an image forming unit that is detachably mounted on the apparatus main body, and a belt unit that has a belt facing each photosensitive drum. And an extrusion mechanism that pushes out the belt unit toward a space in the apparatus main body formed by taking out the image forming unit.

  According to the present invention, when removing the belt unit from the apparatus main body, first, the image forming unit is taken out from the apparatus main body. Thereafter, the belt mechanism is pushed out toward the space (hereinafter also referred to as “image forming portion accommodating space”) formed by taking out the image forming portion by operating the pushing mechanism. Accordingly, even when a disturbing structure is arranged around the belt unit, the belt unit can be pushed out into the image forming unit accommodating space and easily accessed from the outside, so that the belt unit can be easily taken out. Can do.

  According to the present invention, since the extrusion mechanism that pushes out the belt unit toward the image forming unit accommodating space is provided, the belt unit can be easily taken out even when a disturbing structure is arranged around the belt unit. Can do.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a cross-sectional view showing an overall configuration of a color printer as an example of an image forming apparatus, and FIG. 2 is an explanatory view showing a relationship between a side frame of a drawer and a photosensitive drum.

  In the following description, the direction will be described with reference to the user when using the color printer. That is, in FIG. 1, the left side toward the paper surface is “front side (front side)”, the right side toward the paper surface is “rear side (back side)”, and the front side in the direction orthogonal to the paper surface is “right side”. The back side in the direction orthogonal to the “left side” is defined as “left side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, the color printer 1 includes a paper feed tray 2 as an example of a sheet storage unit, a paper feed unit 3 as an example of a supply unit, a scanner unit 4, and a plurality of processes as an image forming unit. A cartridge 5, a belt unit 6, and a fixing device 7 are mainly provided. The scanner unit 4, the plurality of process cartridges 5, the belt unit 6, and the paper feed tray 2 are arranged in an overlapping state from the top to the bottom in that order. The paper feed unit 3 and the fixing device 7 are disposed opposite to each other in the front and rear of the belt unit 6 in a paper conveyance direction, which will be described later. And the apparatus main body 10 which accommodates these has the opening part 10A in the front, and is equipped with the front cover 12 so that opening and closing is possible in the opening part 10A.

  The paper feed tray 2 is a tray that stores paper P as an example of a recording sheet, and is detachable from the front side of the apparatus main body 10 in the front-rear direction with respect to the apparatus main body 10.

  The paper feed unit 3 is a device that supplies the paper P in the paper feed tray 2 to the belt unit 6. The paper feed roller 31, the separation roller 32, the paper dust removing roller 33, the transport roller 34, A guide 3A that reverses the sheet P into a substantially U shape and guides the sheet P onto the belt 61 is provided.

  When the paper feed tray 2 is in the mounting position in the apparatus main body 10, the paper feed roller 31 contacts the paper P in the paper feed tray 2 and sends out the paper P. The separation roller 32 separates the fed paper P one by one from a separation pad (reference numeral omitted) provided on the paper feed tray 2 side.

  The transport roller 34 feeds the paper P upward from the upper surface of the transport belt 61, hits a lower end inclined surface 83 </ b> A of the front frame 83 of the drawer 8, which will be described later, It is guided to the upper surface of the conveyor belt 61 through a gap between the upper ends of the sections. The transport roller 34 also functions as a registration roller (tip alignment member) that feeds the belt P toward the belt unit 6 at a predetermined timing after the leading end of the paper P is stopped at the nip portion of the roller and aligned. There may be.

  The paper feeding unit 3 is arranged at a position overlapping the belt unit 6 when viewed from the front-rear direction (direction in which the paper P is conveyed by the belt unit 6) when the paper P is supplied to the belt unit 6. ing.

  Specifically, the paper feeding unit 3 is disposed at a position between the front cover 12 and the belt unit 6 that are rotatably provided on the front side of the apparatus main body 10. Therefore, when the front cover 12 is simply opened, the belt unit 6 is hidden behind the paper feeding unit 3 as viewed from the direction in which the belt unit 6 transports the paper P and cannot be taken out.

  The sheet feeding unit 3 arranged in this way is fixed to a pair of side frames 11 constituting the left and right walls of the apparatus main body 10. Accordingly, the pair of side frames 11 are reinforced by the paper feed unit 3.

  In the paper feeding unit 3, the paper P in the paper feeding tray 2 is sent out to the separation roller 32 by the paper feeding roller 31, and is separated into one sheet between the separation roller 32 and a separation pad (not shown). Thereafter, after the paper dust is removed by the paper dust removing roller 33, the leading end of the paper P is aligned with the photosensitive drum 51 by the transport roller 34 and is supplied to the belt unit 6.

  The scanner unit 4 has a known structure mainly including a laser light emitting unit, a polygon mirror, a lens, and a reflecting mirror (not shown). The scanner unit 4 irradiates the surface of a photosensitive drum 51 of each process cartridge 5 to be described later with high-speed scanning.

  Each process cartridge 5 includes a rotatable photosensitive drum 51 on which an electrostatic latent image is formed, as well as a known charger, a toner storage chamber, a supply roller, a developing roller, and the like that are not shown. In the process cartridge 5, first, the photosensitive drum 51 charged by the charger is exposed to the laser light emitted from the scanner unit 4, whereby an electrostatic latent image is formed on the surface of the photosensitive drum 51. Thereafter, the toner (developer) in the toner storage chamber is supplied to the electrostatic latent image on the photosensitive drum 51 via a supply roller or the like, and the toner image (developer image) is carried on the photosensitive drum 51.

  The process cartridges 5 are detachably supported by a drawer 8 as an example of an image forming unit holding member in a state where the process cartridges 5 are arranged in the front-rear direction. The drawer 8 is supported by a pair of side frames 11 so as to be movable in the front-rear direction by a known rail member (not shown), and can be pulled out from the opening 10A on the front surface of the apparatus main body 10 and removed. ing.

  As shown in FIG. 2, the side frame 81 of the drawer 8 protrudes downward from the photosensitive drum 51, and the lower end of the side frame 81 is connected to the sheet feeding unit 3 when the drawer 8 is pulled out from the apparatus main body 10. Opposing portions 82 that oppose in the vertical direction are formed. For this reason, when the drawer 8 is pulled out from the apparatus main body 10, the photosensitive drum 51 does not come into contact with the paper feeding unit 3, so that the photosensitive drum 51 can be prevented from being damaged.

  As shown in FIG. 1, the belt unit 6 includes an endless conveyance belt 61 facing each photosensitive drum 51, a driving roller 62 and a driven roller 63 for rotating the conveyance belt 61 while tensioning them. It mainly includes a frame 64 that rotatably supports the rollers 62 and 63. As is well known, the frame 64 has a pair of side walls (not shown) extending in the front-rear direction (the direction in which the paper P is transported by the transport belt 61) on both left and right sides of the transport belt 61, and the front end (opening 10A side). ) And a lower frame portion 64B that covers the front end of the conveyance belt 61 and a lower frame portion 64B that covers the lower surface of the conveyance belt 61 on the same side are bridged between a pair of side walls. Further, the front frame portion is formed with a handle portion 64 </ b> A that is formed in a hook shape that allows a user's finger, jig, or the like to be caught from below. The lower frame portion 64B is formed with a width larger than the width (length in the left-right direction) of the conveyor belt 61.

  The belt unit 6 is detachably supported by the pair of side frames 11. Specifically, the pair of side walls of the frame 64 is placed on each support portion (not shown) protruding in the opposing direction from the pair of side frames 11. As will be described later, when the front end of the belt unit 6 is lifted, the support portion is formed in a long rail shape in the front-rear direction so that the rear ends of the pair of side walls can be slid forward along the support portion. It is preferable to do.

  Then, the belt unit 6 is directed toward an upper image forming unit accommodation space A (a space in the apparatus main body 10 formed by removing the drawer 8; see FIG. 7) by an extrusion mechanism 9 provided in the paper feeding unit 3. When pushed up (pushed out), it is displaced from the position where it overlaps with the paper feed unit 3. The structure of the extrusion mechanism 9 will be described in detail later.

  In the belt unit 6, the paper P can be transported between the transport belt 61 and each photosensitive drum 51. During the conveyance, the toner images on the photosensitive drums 51 are transferred onto the paper P by a plurality of transfer rollers 65 arranged inside the conveyance belt 61.

  The fixing device 7 is a device that heat-fixes the toner image transferred onto the paper P, and includes a known heating roller 71, pressure roller 72, and the like. Then, the paper P heat-fixed by the fixing device 7 is discharged to the outside of the apparatus main body 10 by a conveyance roller that is not shown in the reference numerals.

<Structure of extrusion mechanism>
Next, the structure of the extrusion mechanism 9 will be described in detail. In the drawings to be referred to, FIG. 3 is an enlarged perspective view showing an extrusion mechanism in an initial state, and FIG. 4 is an enlarged perspective view showing the extrusion mechanism in a state operated by an operator. FIG. 5 is a side view (a) showing the relationship between the extrusion mechanism and the belt unit in the initial state, and a side view (b) showing the relationship between the extrusion mechanism and the belt unit operated by the operator. . FIG. 6 is an explanatory view showing the position of the pressing member.

  As shown in FIG. 3, the extrusion mechanism 9 mainly includes an operation member 91, a pressing member 92, and a link mechanism 93, and is integrally assembled to the right side portion of the casing 35 of the paper feed unit 3.

  The operation member 91 is a member operated by an operator (such as a user or a repair shop), and is in an upright state as shown in FIG. When it is brought down, it becomes a recumbent state as shown in FIG. The operation member 91 includes a shaft portion 91A that is rotatably supported by the casing 35 of the sheet feeding unit 3, a plate-like portion 91B that extends radially outward from the shaft portion 91A, and a diameter from the plate-like portion 91B. An operation portion 91C that protrudes outward in the direction is mainly provided.

  The plate-like portion 91B is formed in a fan-like plate shape with the shaft portion 91A as a center, and an engagement shaft B1 is formed at an appropriate position on the rear side thereof so as to be pivotably engaged with the link mechanism 93. Ribs B2 and B3 surrounding the engagement shaft B1 are formed above and in front of the engagement shaft B1. Thereby, since it can prevent by an rib B2, B3 that an operator touches engagement shaft B1, it is suppressed that the link mechanism 93 is accidentally removed from engagement shaft B1 by the operator.

  The operation portion 91C is a portion for hooking the operator's finger, is disposed on the front side of the upper rib B2 of the plate-like portion 91B, and is exposed to the outside from the opening on the front surface of the housing 35. More specifically, the operation unit 91 </ b> C is disposed closer to the front side (front cover 12 side) than the conveyance roller 34 in an initial state where the operation unit 91 is not operated by an operator.

  As shown in FIGS. 5A and 5B, the pressing member 92 is a member that presses the lower frame portion 64 </ b> B of the belt unit 6 upward. Then, the lower frame portion 64B is pressed by the pressing member 92 in this manner, so that the handle portion 64A of the belt unit 6 is pushed out from the opening 10A (see FIG. 1) of the apparatus main body 10 to an accessible position. It has become. That is, when the lower frame portion 64B is pressed by the pressing member 92, a gap that allows the operator's finger to enter is formed between the handle portion 64A and the upper surface 35A of the housing 35.

  Specifically, as shown in FIG. 3, the pressing member 92 includes a base portion 92A that rotates about a link shaft 93C (shaft portion) that extends in the left-right direction (the width direction of the transport belt 61), and a base portion 92A. It is formed in an L shape by an extending portion 92B extending inward in the left-right direction. The base 92A is fixed to the link shaft 93C, so that the pressing member 92 rotates together with the link shaft 93C.

  Further, as shown in FIG. 6, the pressing member 92 is disposed at a position where a portion (range X) corresponding to the width of the conveyor belt 61 in the lower frame portion 64B can be pressed. Specifically, a sheet feeding roller 31 formed with a width smaller than the width of the conveyor belt 61 is disposed below the lower frame portion 64B. The sheet feeding roller 31 and the pressing member 92 are arranged in the left-right direction ( They are shifted from each other in the width direction of the conveyor belt 61. In other words, the pressing member 92 is a portion (X range) corresponding to the width of the conveyance belt 61 in the lower frame portion 64B, and other than a portion corresponding to the width of the paper feed roller 31 (Y range). It is arranged at the position to press the part.

  As shown in FIG. 3, the link mechanism 93 is a mechanism that transmits the force applied to the operation member 91 to the pressing member 92, and includes a link arm 93A, a swinging member 93B, and a link shaft 93C. ing.

  The link arm 93A is a long member, and its front end is rotatably supported by the engagement shaft B1 of the operation member 91, and its rear end is rotatable by the engagement shaft B11 of the swinging member 93B. It is supported by. The link arm 93 </ b> A is moved by being pulled forward by the operation member 91 when the operation member 91 is tilted forward.

  As shown in FIG. 5A, the swing member 93B is an egg-shaped member in a side view that tapers toward the outer side in the radial direction of the link shaft 93C, and a base portion that has a large diameter portion on the link shaft 93C. It is fixed and can rotate integrally with the link shaft 93C. Further, an engaging shaft B11 that supports the above-described link arm 93A so as to be rotatable is formed at the tip of the swing member 93B.

  Then, when the operating member 91 is tilted forward and the link arm 93A moves forward, the swinging member 93B is pulled by the link arm 93A and swings forward. That is, the rocking member 93B is also rocked in conjunction with the rocking of the operation member 91, the pressing member 92 is erected, and the front end of the belt unit 6 is lifted. The swing amount of the operation member 91 and the swing amount of the swing member 93B can be set to appropriate values by changing the length relationship and arrangement of the swing member 91, the link arm 93A, and the swing member 93B. .

  Further, the swinging member 93B is always urged rearward by a torsion spring 94 as an example of an urging member, whereby the swinging member 93B rotates together with the oscillating member 93B and the link shaft 93C. The moving pressing member 92 is always urged to the initial position (the recumbent state shown in FIG. 5A). The torsion spring 94 is disposed coaxially with the center of rotation of the swing member 93 </ b> B, and has one end engaged with the swing member 93 </ b> B and the other end engaged with the casing 35 of the paper feed unit 3. is doing.

<Removal method of belt unit>
Next, a method for attaching and detaching the belt unit 6 will be described. In the drawings to be referred to, FIGS. 7A to 7C are explanatory views showing a method for attaching and detaching the belt unit.

  As shown in FIGS. 7A and 7B, when removing the belt unit 6 from the apparatus main body 10, the operator first opens the front cover 12 and removes the drawer 8 from the opening 10 </ b> A of the apparatus main body 10. Remove through. At this time, since the operator only has to open the light front cover 12 to which the paper feeding unit 3 is not fixed integrally, it is possible to easily perform the work without feeling a burden. In this state, the process cartridge 5 or the toner container in the process cartridge can be exchanged for the drawer 8.

  Thereafter, as shown in FIGS. 5 (a) and 5 (b), the operator tilts the operation member 91 of the push-out mechanism 9 toward the front, thereby pressing the push member of the push-out mechanism 9 as shown in FIG. 7 (c). At 92, the belt unit 6 is pushed up into the image forming unit accommodating space A. As a result, the handle portion 64 </ b> A of the belt unit 6 moves above the paper feed unit 3, and a gap is formed between the lower end surface of the handle portion 64 </ b> A and the upper surface of the paper feed unit 3.

  Then, the operator puts the other hand into the gap formed between the lower end surface of the handle portion 64A and the upper surface of the paper feed unit 3 while keeping the operation member 91 in a state of being tilted with one hand, Hook on the handle 64A. Thereafter, the belt unit 6 is removed through the opening 10A of the apparatus main body 10 by pulling the handle 64A forward.

  When one hand is released from the operation member 91 after the belt unit 6 is removed from the apparatus main body 10, the pressing member 92 returns to the initial position (recumbent state) by the urging force of the torsion spring 94 (see FIG. 5). Thereby, when a new belt unit 6 or a belt unit 6 after cleaning is attached to the apparatus main body 10, the belt unit 6 can be smoothly moved without being disturbed by the standing pressing member 92. Mounted on the apparatus main body 10.

According to the above, the following effects can be obtained in the present embodiment.
Since the push-out mechanism 9 that pushes the belt unit 6 toward the image forming unit accommodating space A is provided, even if a disturbing structure such as the paper feed unit 3 is arranged around the belt unit 6, the belt unit 6 can be easily taken out. In particular, in the direct tandem type color printer 1 in which the belt unit 6 and the paper feeding unit 3 are arranged so as to overlap each other when viewed from the front and rear as in the above-described embodiment, the belt unit 6 is located above the paper feeding unit 3. Thus, the belt unit 6 can be satisfactorily taken out substantially in the front-rear direction of the apparatus main body 10.

  The push-out mechanism 9 pushes up the handle 64A of the belt unit 6 to a position accessible from the opening 10A, so that both the drawer 8 and the belt unit 6 can be attached and detached from the same opening 10A, and the operability is improved. be able to. In particular, in the embodiment, since the opening 10A is formed on the front side of the apparatus body 10, the operator can easily attach and detach both the drawer 8 and the belt unit 6 from the front side.

  Since the sheet feeding unit 3 includes the conveyance roller 34, the conveyance roller 34 can be disposed near the belt unit 6 adjacent to the rear of the sheet feeding unit 3, so that the leading end position of the sheet P with respect to the image on the photosensitive drum 51. The sheet P can be transported with accurate regulation.

  Since the lower frame portion 64B that covers the lower side of the conveyance belt 61 is provided and the lower frame portion 64B is pressed by the extrusion mechanism 9, it is possible to prevent the conveyance belt 61 from being damaged by the extrusion mechanism 9. . Further, since the portion corresponding to the width of the conveyor belt 61 in the lower frame portion 64B is pushed by the pushing mechanism 9, the belt unit 6 is prevented from being tilted to the left and right as compared with the structure in which the left and right ends of the lower frame portion 64B are pushed. be able to.

  Since the sheet feeding roller 31 and the pressing member 92 are arranged so as to be shifted from each other in the belt width direction, the sheet feeding roller 31 and the pressing member 92 can be brought closer to the vertical direction than in the above embodiment, and the entire apparatus is Can be reduced in size.

  Since the operation member 91 and the pressing member 92 are connected by the link mechanism 93, the operation member 91 can be set at an arbitrary position, and the degree of freedom in design can be increased.

  Since the operation portion 91C of the operation member 91 is disposed on the front cover 12 side with respect to the conveyance roller 34, the operation portion 91C can be easily operated as compared with the structure in which the operation portion is disposed behind the conveyance roller 34. .

  Since the extrusion mechanism 9 is provided integrally with the paper feed unit 3, the extrusion mechanism 9 can be assembled to the apparatus main body 10 together with the paper feed unit 3.

  By constantly urging the pressing member 92 to the initial position by the torsion spring 94, after the belt unit 6 is removed and the operation member 91 is released, the pressing member 92 automatically returns to the initial position. 6 can be mounted smoothly without hindering the mounting of the belt unit 6 by the pressing member 92.

  Since the extending portion 92B extending inward in the left-right direction from the base portion 92A of the pressing member 92 is provided, even if the entire base portion 92A cannot be extended inward in the left-right direction, the extension portion 92B pushes the vicinity of the center of the belt unit 6. The belt unit 6 can be pushed up stably.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above-described embodiment, the conveyance belt 61 is used as the belt. However, the present invention is not limited to this. For example, as illustrated in FIG. 8A, a toner image carried on each photosensitive drum 51 includes a plurality of toner images. An intermediate transfer belt MB transferred by the next transfer roller FR (primary transfer member) may be employed.

  Specifically, in the form of FIG. 8, the secondary transfer roller SR (secondary transfer member) that transfers the toner image carried on the intermediate transfer belt MB onto the paper P transfers the toner image onto the paper P. The belt unit BU overlaps with the belt unit BU as viewed from the front-rear direction (direction in which the photosensitive drums 51 are arranged). Further, an extrusion mechanism PM having a piston PS that moves up and down is provided below the front side of the belt unit BU.

  In this embodiment, as shown in FIG. 8B, after the front cover 12 is opened and the drawer 8 is taken out, the belt unit BU is pushed out to the upper image forming unit accommodating space A by the push-out mechanism PM. Is displaced from the position where it overlaps the secondary transfer roller SR. Therefore, even in such an intermediate transfer tandem form, the belt unit BU can be easily displaced from the secondary transfer roller SR by the extrusion mechanism PM.

  In the above-described embodiment, when the belt unit 6 is removed, the operation member 91 is held while being tilted by hand. However, the present invention is not limited to this, and the belt unit is held at a position where it is pushed out by the extrusion mechanism. A holding unit may be provided in the apparatus main body. For example, as shown in FIGS. 9A to 9C, hemispherical engagement portions 66 that protrude outward in the left-right direction are provided on the left and right side surfaces of the belt unit 6, and the apparatus body 10 protrudes inward in the left-right direction. A cylindrical holding portion 13 may be provided.

  According to this, when the belt unit 6 is pushed up by the pressing member 92, the engaging portion 66 gets over the holding portion 13 and is held by the holding portion 13 as shown in FIGS. 9B and 9C. The Therefore, the operator does not need to keep the operation member 91 pressed by hand, and the belt unit 6 can be removed more easily.

  Note that the push-out mechanism is not limited to one in which the pressing member rotates, but can be one that moves up and down. In addition to operating the pressing member via the link mechanism from the operating member, it is also possible to directly operate the pressing member.

In the above embodiment, the drawer 8 that integrally supports the plurality of process cartridges 5 is provided. However, the present invention is not limited to this, and the present invention is not limited to this. The invention can be applied.
In the above embodiment, the process cartridge 5 is detachably supported by the drawer 8, but the photosensitive drum may be directly supported by the drawer, and the toner storage unit may be detachably attached to the drawer 8.

  In the above-described embodiment, the torsion spring 94 is employed as the urging member. However, the present invention is not limited to this, and for example, a coil spring or a leaf spring can be employed. In the above embodiment, the urging member is engaged with the link mechanism. However, the present invention is not limited to this, and the urging member is engaged with the operation member or the pressing member to attach the pressing member to the initial position. You may make it rush.

  In the above-described embodiment, the structure in which the drawer 8 (each process cartridge 5) and the belt unit 6 are attached and detached through the opening 10A that is opened and closed by the front cover 12 is adopted, but the present invention is not limited to this. For example, the present invention may be applied to a structure in which a belt unit or the like is attached and detached through an opening that is opened and closed by a top cover provided on the upper part of the apparatus main body.

In the above embodiment, the present invention is applied to the color printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.
In the above-described embodiment, paper P such as thick paper, postcard, and thin paper is used as an example of the recording sheet. However, the present invention is not limited to this, and may be, for example, an OHP sheet.

  In the above-described embodiment, the conveyance roller 34 is used as the leading edge aligning member. However, the present invention is not limited to this. For example, the conveying roller 34 is in contact with a plurality of positions at the leading end of the recording sheet and the leading end position is aligned. You may employ | adopt the several board | plate material etc. which evacuate from a conveyance path | route.

1 is a cross-sectional view illustrating an overall configuration of a color printer as an example of an image forming apparatus. It is explanatory drawing which shows the relationship between the side frame of a drawer, and a photosensitive drum. It is an expansion perspective view which shows the extrusion mechanism of an initial state. It is an expansion perspective view which shows the extrusion mechanism of the state operated by the operator. FIG. 4 is a side view (a) showing a relationship between an extrusion mechanism and a belt unit in an initial state, and a side view (b) showing a relationship between the extrusion mechanism and a belt unit operated by an operator. It is explanatory drawing which shows the position of a press member. (A)-(c) is explanatory drawing which shows the attachment or detachment method of a belt unit. FIG. 2 is an explanatory view showing a form in which the present invention is applied to an intermediate transfer tandem, an explanatory view (a) showing a state where an intermediate transfer belt or the like is mounted on the apparatus main body, and a space after the drawer is taken out from the apparatus main body. It is explanatory drawing (b) which shows the state which pushed up the belt unit. It is a figure which shows the modification which provided the holding | maintenance part in the apparatus main body, the side view (a) which shows the state which is not hold | maintaining the belt unit with a holding | maintenance part, the side view (b) which shows the state hold | maintained, and sectional drawing ( c).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color printer 3 Paper feed unit 5 Process cartridge 6 Belt unit 8 Drawer 9 Extrusion mechanism 10 Apparatus main body 10A Opening part 12 Front cover 31 Paper feed roller 34 Conveyance roller 51 Photosensitive drum 61 Conveyance belt 64A Handle part 64B Lower frame part 91 Operation member 92 Pressing member 92A Base portion 92B Extension portion 93 Link mechanism 94 Torsion spring A Image forming portion accommodation space P Paper

Claims (13)

An image forming unit having a plurality of photosensitive drums and detachably mounted on the apparatus main body;
An image forming apparatus including a belt unit having a belt facing each photosensitive drum,
An image forming apparatus, further comprising an extrusion mechanism that pushes out the belt unit toward a space in the apparatus main body formed by taking out the image forming unit. The belt is a conveyance belt that conveys a recording sheet to and from each photosensitive drum,
The supply unit that supplies the recording sheet to the belt unit overlaps the belt unit when viewed from the direction in which the recording sheet is conveyed by the belt unit when the recording sheet is supplied to the belt unit. The image forming apparatus according to claim 1, wherein: The belt is an intermediate transfer belt on which a developer image carried on each photosensitive drum is transferred by a plurality of primary transfer members,
When the secondary transfer member that transfers the developer image carried on the intermediate transfer belt to the recording sheet is in a state of transferring the developer image to the recording sheet, the photosensitive drums are viewed from the direction in which they are aligned. It overlaps with the belt unit,
The image forming apparatus according to claim 1, wherein when the belt unit is pushed out by the extrusion mechanism, the belt unit is displaced from a position where the belt unit overlaps the secondary transfer member. An image forming unit holding member that holds the image forming unit and can be pulled out from the apparatus main body;
An opening formed in the apparatus main body for pulling out the image forming unit holding member from the apparatus main body,
A handle is formed on the opening side of the belt unit,
The image forming apparatus according to claim 1, wherein the push-out mechanism is configured to push out a handle portion of the belt unit to a position accessible from the opening. An image forming unit holding member that holds the image forming unit and can be pulled out from the apparatus main body;
An opening formed in the apparatus main body for pulling out the image forming unit holding member from the apparatus main body;
A front cover that opens and closes the opening,
The supply unit is disposed between the front cover and the belt unit;
A handle is formed on the opening side of the belt unit,
The image forming apparatus according to claim 2, wherein the push-out mechanism is configured to push the handle portion of the belt unit to a position accessible from the opening.   The image forming apparatus according to claim 2, wherein the supply unit includes a leading edge aligning member for aligning a leading end position of the recording sheet with respect to the photosensitive drum. The belt unit has a lower frame that covers a lower side of the belt,
The image forming apparatus according to claim 1, wherein the pushing mechanism is configured to push a portion of the lower frame corresponding to a width of the belt. The belt unit has a lower frame that covers a lower side of the belt,
A supply roller that feeds out a recording sheet from a sheet storage portion that stores the recording sheet is formed smaller than the width of the belt, and is disposed below the lower frame,
The image forming apparatus according to claim 1, wherein the extrusion mechanism and the supply roller are arranged so as to be shifted from each other in the width direction of the belt. The extrusion mechanism is
An operation member operated by an operator;
A pressing member that presses the lower frame;
The image forming apparatus according to claim 7, further comprising: a link mechanism that transmits a force applied to the operation member to the pressing member.   The image forming apparatus according to claim 9, wherein the operation portion of the operation member is disposed closer to the front cover than the tip alignment member.   The image forming apparatus according to claim 9, wherein the push-out mechanism is provided integrally with the supply unit.   The urging member for urging the pressing member to an initial position by engaging with any one of the operating member, the pressing member, and the link mechanism is further provided. 2. The image forming apparatus according to item 1. The pressing member is
A base that rotates about a shaft that extends in the width direction of the belt;
The image forming apparatus according to claim 9, wherein the image forming apparatus is formed in an L shape by an extending portion extending inward in the width direction from the base portion.

Images