JP2010276905A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of readily performing a belt unit maintenance work. <P>SOLUTION: The image forming apparatus (color printer 100) includes: a belt unit (paper conveying belt unit 600) disposed facing image forming sections (process cartridges 500); a conveying path unit (both-side conveying path unit 800), disposed on the side opposite to the image forming sections across the belt unit; a sheet storing unit, disposed underneath the conveying path unit, for storing a recording sheet therein; a retracting mechanism 150 for retracting the conveying path unit into a space S1, where the sheet storing unit is disposed; and a holding mechanism 900, which holds the belt unit so that the belt unit can be freely attached/removed to/from the apparatus body 110. The belt unit is displaceable up to the space S1 where the sheet storing unit is disposed via a space S2, where the conveying path unit retracted by the retracting mechanism 150 lies. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a belt unit facing an image forming unit.

  2. Description of the Related Art Conventionally, a plurality of process cartridges (image forming units) having photosensitive drums, a belt unit having a belt which is disposed opposite to each photosensitive drum and conveys paper between the photosensitive drums, and each process cartridge. An image forming apparatus is known that includes a drawer that can be integrally supported and can be pulled out from the apparatus main body (see Patent Document 1). With this technology, when performing maintenance (replacement, cleaning, jamming, etc.) around the belt unit, the belt unit is removed from the apparatus body through the space formed by removing the drawer and then removing the drawer. Yes.

  Each process cartridge and the drive source are connected to each component (for example, a photosensitive drum) provided in each process cartridge via a coupling or the like so as to transmit a drive force from the drive source of the apparatus main body. Therefore, when performing maintenance around the belt unit, the drive source of the apparatus main body and each process cartridge are disconnected, and then the drawer is pulled out.

JP 2007-57953 A

  However, in the conventional technology, when performing maintenance around the belt unit, it is necessary to disconnect the plurality of process cartridges from the drive source of the apparatus main body, which takes time and troubles. It was. Further, there has been a demand that the process cartridge necessary for image formation does not need to be attached and detached as frequently as possible.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can simplify maintenance work of a belt unit.

  The present invention that solves the above-described problem is an image forming apparatus in which an image forming unit and a belt unit are disposed to face each other in the apparatus main body, and is disposed on the opposite side of the image forming unit with the belt unit interposed therebetween. A transport path unit that transports the sheet along the belt surface of the belt unit; a sheet storage section that is disposed below the transport path unit and stores a recording sheet; and a space in which the sheet storage section is disposed. A retracting mechanism for retracting the transport path unit; and a holding mechanism for detachably holding the belt unit to and from the apparatus main body, and the belt unit is retracted by the retracting mechanism when detached from the holding mechanism. It is possible to displace to the space where the sheet storage unit is arranged through the space where the transport path unit is present.

  According to the present invention, for example, after all the recording sheets in the sheet storage unit are pulled out to secure a space in the sheet storage unit, the transport path unit is retracted in this space by the retraction mechanism, so that the transport path unit The sheet can be moved to the space in the sheet storage portion through the existing space. Therefore, in the present invention, the belt unit can be maintained from the sheet storage unit side without removing the image forming unit.

  According to the present invention, since the belt unit can be maintained from the sheet storage unit side without removing the image forming unit, the maintenance work of the belt unit can be simplified.

1 is an explanatory diagram illustrating an overall configuration of a color printer as an example of an image forming apparatus. FIG. FIG. 6 is an explanatory diagram illustrating a structure for attaching and detaching a paper transport belt unit. FIG. 6 is an explanatory diagram illustrating a state where a paper feed tray is pulled out from the apparatus main body. FIG. 6 is an explanatory diagram illustrating a state in which a paper conveyance belt unit and a double-sided conveyance path unit are swung downward. FIG. 10 is an explanatory diagram illustrating an operation of removing the paper transport belt unit from the apparatus main body. 2A and 2B are diagrams illustrating an embodiment in which the present invention is applied to an intermediate transfer type color printer, an explanatory diagram illustrating each configuration in the color printer, and an explanatory diagram illustrating a state in which a paper feed tray is pulled out from the apparatus main body. ). FIG. 6A is an explanatory view showing a state in which the intermediate transfer belt unit and the manual feed path unit in FIG. 6A are swung downward, and FIG. 6B is an explanatory view showing an operation of removing the intermediate transfer belt unit from the apparatus main body. ).

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
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 right side toward the paper surface is “front side (front side)”, the left side toward the paper surface is “rear side (back side)”, the back side in the direction orthogonal to the paper surface is “right side”, and the paper surface The near side in the orthogonal direction is defined as the “left side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, a color printer 100 includes a paper feed tray 200 as an example of a sheet storage unit, a paper feed unit 300, a scanner unit 400, and a plurality of process cartridges 500 as an example of an image forming unit. I have. Furthermore, the color printer 100 includes a paper conveyance belt unit 600 as an example of a belt unit, a fixing device 700, and a duplex conveyance path unit 800 as an example of a conveyance path unit.

  In the color printer 100, a scanner unit 400, a plurality of process cartridges 500, a paper transport belt unit 600, a duplex transport path unit 800, and a paper feed tray 200 are sequentially arranged from top to bottom. A paper feed unit 300 is arranged in front of the paper conveyance belt unit 600 and the double-sided conveyance path unit 800, and a fixing device 700 is arranged behind the paper conveyance belt unit 600. An opening 111 for attaching / detaching the process cartridge 500 (drawer 520 to be described later) to the front and rear and an outlet 112 for attaching / detaching the paper feed tray 200 to the front and rear are provided on the front surface of the box-shaped apparatus main body 110 that accommodates them. The front cover 120 is provided in the opening 111 so as to be openable and closable.

  The paper feed tray 200 is a tray that stores paper P as an example of a recording sheet, and is detachable by sliding in the front-rear direction with respect to the apparatus main body 110 from the front side of the apparatus main body 110. The paper feed tray 200 is provided with a handle portion 210 that is gripped by the user on the front surface thereof.

  The paper feed unit 300 is a device that supplies the paper P in the paper feed tray 200 and the paper P sent from the duplex conveyance path unit 800 to the paper conveyance belt unit 600. The paper feed unit 300 guides the paper from the paper feed roller 310 in contact with the paper P in the paper feed tray 200, a registration roller 320 for aligning the position of the front end of the paper P, and the paper feed roller 310 to the registration roller 320. The sheet feeding guide members 331 and 332, and the double-sided guide member 333 that guides the paper P sent from the double-sided conveyance path unit 800 to the registration roller 320 are provided.

  The scanner unit 400 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 400 irradiates the surface of a photosensitive drum 510 of each process cartridge 500 (described later) with high-speed scanning.

  Each process cartridge 500 includes a photosensitive drum 510 on which an electrostatic latent image is formed, and a known charger, a toner storage chamber, a supply roller, a developing roller, and the like (not shown). The process cartridges 500 are integrally supported by the drawer 520 in a state where they are arranged in the front-rear direction. The drawer 520 is supported by a known guide rail (not shown) provided on a pair of side frames 114 constituting the left and right walls of the apparatus main body 110 so as to be movable back and forth, and an opening formed by opening the front cover 120. It can be pulled out from 111.

  In this process cartridge 500, first, the photosensitive drum 510 charged by the charger is exposed to the laser light emitted from the scanner unit 400, thereby forming an electrostatic latent image on the surface of the photosensitive drum 510. . Thereafter, toner (developer) in the toner storage chamber is supplied to the electrostatic latent image on the photosensitive drum 510 via a supply roller or the like, and a toner image (developer image) is carried on the photosensitive drum 510.

  The paper transport belt unit 600 is configured to rotate an endless belt 610 facing each photosensitive drum 510, a driving roller 620 and a driven roller 630 for rotating the belt 610, and the rollers 620 and 630. And a frame 640 to be supported. The sheet conveying belt unit 600 can be attached to and detached from the apparatus main body 110 through an outlet 112 of a paper feed tray 200 provided on the front surface of the apparatus main body 110. The structure for attaching and detaching the paper transport belt unit 600 will be described in detail later.

  In this paper transport belt unit 600, the paper P is placed on the upper surface of the belt 610 (the surface on the side of each photosensitive drum 510), and the belt 610 and each photosensitive drum 510 rotate while pinching the paper P. The paper P is conveyed. During this conveyance, the toner images on the respective photosensitive drums 510 are transferred onto the paper P by a plurality of transfer rollers 650 arranged inside the belt 610.

  The fixing device 700 is a device that thermally fixes the toner image transferred to the paper P, and includes a heating roller 710, a pressure roller 720, and the like. The paper P thermally fixed by the fixing device 700 is discharged to a paper discharge tray 113 formed on the main body 110 by the paper discharge roller 130.

  The paper discharge roller 130 returns the paper P into the apparatus main body 110 by rotating in reverse before discharging the entire paper P onto the paper discharge tray 113 during double-sided printing. The sheet P returned into the apparatus main body 110 is guided by the upper surface of the flapper 140 that swings downward, and then passes through the rear side of the fixing apparatus 700 and is then sent to the duplex conveyance path unit 800.

  The double-sided conveyance path unit 800 is a conveyance device for double-sided conveyance, and is disposed on the opposite side of each process cartridge 500 with the paper conveyance belt unit 600 interposed therebetween. Here, “double-sided conveyance” refers to returning the paper P to the upstream side in the paper conveyance direction of each process cartridge 500 with the front and back sides reversed in order to print the back surface of the paper P on which the front surface is printed. Refers to the conveyance to be performed.

  The double-sided conveyance path unit 800 has a guide member 810 for switching the direction of the sheet P conveyed downward through the rear side of the fixing device 700 to the front, and the sheet P guided by the guide member 810 facing the front. A plurality of pairs of return rollers 820 arranged in front and rear for conveyance, and a frame 830 on which the guide member 810 is fixed and rotatably supports the return roller 820 are provided.

  In the double-sided conveyance path unit 800, the paper P is aligned in the horizontal direction, specifically, along the belt surface 660 of the paper conveyance belt unit 600 (the surface outside the belt 610 and facing the double-sided conveyance path unit 800). It is transported to. The structure in which the duplex conveying path unit 800 is supported by the apparatus main body 110 will be described in detail later.

<Structure to attach / detach belt unit>
Next, details of the structure for attaching and detaching the paper transport belt unit 600 will be described.
As shown in FIG. 2, the color printer 100 includes a retreat mechanism 150 that retracts the double-sided conveyance path unit 800 in a space S1 (see FIG. 4) in which the paper feed tray 200 is disposed, and a double-sided conveyance path. And a holding mechanism 900 that is detachably held on the apparatus main body 110 via the unit 800.

  The retraction mechanism 150 is provided with a pair of bearing members 151 provided on the left and right side frames 114 of the apparatus main body 110 and a pair of protrusions that protrude outward in the left-right direction on the rear side of the left and right frames 830 of the duplex conveyance path unit 800. The rotation shaft portion 152 is provided.

  Each rotary shaft portion 152 is rotatably supported by each bearing member 151 so that the double-sided conveyance path unit 800 has the front end side as a swing end with the rear end side rotary shaft portion 152 as a swing center. The apparatus main body 110 is swingably supported. In other words, the swing end (front end) of the double-sided conveyance path unit 800 is disposed on the side of the outlet 112 as an example of an opening for taking out the paper P.

  Here, the “opening for taking out the paper P (recording sheet)” means an opening (drawing port 112) for taking out the paper P together with the paper feed tray 200 (sheet storage unit) in this embodiment. When the sheet storage portion is not removable from the apparatus main body, it means an opening formed in the sheet storage section formed as a part of the apparatus main body.

  The holding mechanism 900 includes a lock mechanism 910 provided in the apparatus main body 110 and a pair of support arms 920 as an example of a support unit that supports the paper transport belt unit 600.

  The lock mechanism 910 is a mechanism that holds the double-sided conveyance path unit 800 in the apparatus main body 110, and a pair of hooks 911 that are rotatably provided on the left and right side frames 114 of the apparatus main body 110, and the hooks 911 in a predetermined position. An urging member (not shown) such as a torsion spring for urging is provided. The hook 911 is bent in an L shape, and one end of the hook 911 is rotatably supported by the side frame 114.

  On the front side of the left and right frames 830 of the double-sided conveyance path unit 800, a pair of engagement protrusions 831 that protrude outward in the left-right direction are provided. The engagement protrusion 831 is supported on the other end side of the hook 911.

  The support arm 920 is a substantially T-shaped member and is provided on the upper front side of the left and right frames 830 of the double-sided conveyance path unit 800. On the other hand, the left and right frames 640 of the paper transport belt unit 600 are provided with a pair of front protrusions 642 and a pair of rear protrusions 643 that are spaced apart from each other in the front-rear direction and protrude outward in the left-right direction.

  In the sheet conveying belt unit 600, the protrusion 643 is then supported by a guide groove 160 of a side frame 114, which will be described later, and the front protrusion 642 is supported by a support arm 920. 2 (position at the time of image formation). Further, the front protrusion 642 of the sheet conveying belt unit 600 is arranged so as to be shifted inward in the left-right direction from the guide groove 160 so as not to enter the guide groove 160.

  Therefore, when the double-sided conveyance path unit 800 is swung, the sheet conveying belt unit 600 supported by the support arm 920 is also swung together with the rear protrusion 643 as a rocking center. That is, in the paper transport belt unit 600, the front end (front protrusion 642) as the swing end on the outlet 112 side is supported by the front end (support arm 920) as the swing end of the double-side transport path unit 800. The front end of the paper transport belt unit 600 moves up and down in conjunction with the up and down movement of the front end of the double-sided transport path unit 800 and swings.

  Note that the upper surface 921 of the support arm 920 can maintain the support of the front protrusion 642 of the paper transport belt unit 600 even when the double-sided transport path unit 800 is swung to the lowermost retracted position (see FIG. 4). It is formed with a length. That is, the support arm 920 moves forward between the double-sided conveyance path unit 800 between the holding position where the apparatus main body 110 is held (the position shown in FIG. 2) and the above-described retracted position (the position shown in FIG. 4). 642 is configured to be supported while being in sliding contact.

  The left and right side frames 114 of the apparatus main body 110 support the rear protrusions 643 of the paper conveyance belt unit 600 and guide grooves for guiding the paper conveyance belt unit 600 to the outside of the apparatus main body 110 or inside the apparatus main body 110. 160 is formed. That is, each side frame 114 guides the paper conveyance belt unit 600 to draw out the paper conveyance belt unit 600 out of the apparatus main body 110 or to mount the paper conveyance belt unit 600 from the outside of the apparatus main body 110 to the inside. It has become.

  Specifically, the guide groove 160 has a first groove 161 that supports the rear protrusion 643 when the paper conveyance belt unit 600 is located at the above-described attachment position (position in FIG. 2), and the first groove 161. A second groove 162 formed at a position one step lower than the front groove and a third groove 163 formed one step lower than the second groove 162 are integrally and continuously provided. The third groove 163 is opened from the outlet 112 toward the outside of the apparatus main body 110, so that the sheet conveying belt unit 600 can be attached to and detached from the apparatus main body 110 through the outlet 112.

  The first groove 161, the second groove 162, and the third groove 163 extend in parallel with each other along the front-rear direction, and are continuously formed via connecting grooves 164, 165 extending obliquely. The rear end portion of the rear connecting groove 164 (the portion where the connecting groove 164 starts to drop from the first groove 161) is positioned rearward of the rearmost photosensitive drum 510, so that it is guided by the guide groove 160. Interference between a portion around the rear protrusion 643 of the paper conveyance belt unit 600 and the rearmost photosensitive drum 510 is suppressed. Further, the guide groove 160 is formed at a position away from the double-sided conveyance path unit 800 positioned at the retracted position by a predetermined distance, and thereby, the portion around the rear protrusion 643 of the paper conveyance belt unit 600 and the double-sided conveyance path. Interference with the unit 800 is suppressed.

  In addition, a handle portion 641 is provided at the front portion of the frame 640 of the paper transport belt unit 600 to be gripped by a user, a repairer, or the like. Furthermore, a handle portion 832 that is gripped by a user or the like is also provided at the front portion of the frame 830 of the duplex conveyance path unit 800.

<Attaching / detaching the paper transport belt unit>
Next, a method for attaching and detaching the paper conveyance belt unit 600 will be described.
When removing the paper transport belt unit 600 from the apparatus main body 110, first, the user or the like pulls the paper feed tray 200 into the apparatus by placing a finger on the handle 210 of the paper feed tray 200 as shown in FIG. Remove from the main body 110.

  Thereafter, when the user or the like holds the handle portion 832 of the duplex conveyance path unit 800 and removes the hook 911 from the engagement protrusion 831 of the duplex conveyance path unit 800 and swings the duplex conveyance path unit 800 downward, FIG. As shown in FIG. 5, the sheet conveying belt unit 600 swings downward together with the duplex conveying path unit 800. As a result, since the paper conveyance belt unit 600 is separated from each photosensitive drum 510, when the paper P is jammed between the paper conveyance belt unit 600 and each photosensitive drum 510, the jammed paper P is transferred to the paper conveyance belt unit. The sheet is placed on 600 or slides on the upper surface of the inclined sheet conveying belt unit 600 and falls to the outlet 112 side. Therefore, a user or the like can easily perform a process (hereinafter, also referred to as “jam process”) for taking out the jammed paper P by putting his hand through the outlet 112.

  Further, when the sheet conveying belt unit 600 swings downward together with the duplex conveying path unit 800, the handle portion 641 of the sheet conveying belt unit 600 faces the outside from the outlet 112. This makes it easy for the user or the like to grip the handle portion 641.

  Thereafter, when the user or the like grasps the handle portion 641 facing the outside and lifts and pulls it slightly, the rear protrusion 643 is guided by the guide groove 160 as shown in FIG. Without interfering with the photosensitive drum 510 and the double-sided conveyance path unit 800, it is pulled out from the outlet 112 and maintained (replacement, cleaning, etc.). In other words, the paper transport belt unit 600 is moved (displaced) to the space S1 where the paper feed tray 200 was present via the space S2 where the double-sided transport path unit 800 was present, and then removed from the apparatus main body 110. Maintenance.

  When the paper transport belt unit 600 is mounted on the apparatus main body 110, the user or the like inserts the rear protrusion 643 of the paper transport belt unit 600 to the rear end in the guide groove 160, as shown in FIG. Then, the front protrusion 642 is placed on the support arm 920 of the duplex conveyance path unit 800. Thereafter, the user or the like grips and lifts the handle portion 832 of the double-sided conveyance path unit 800 to swing the front end of the double-sided conveyance path unit 800 and the front end of the paper conveyance belt unit 600 together as shown in FIG. Move.

  When the front end of the duplex conveyance path unit 800 is raised to a predetermined position, the hook 911 is pushed backward by the engagement protrusion 831 of the duplex conveyance path unit 800, and then the hook 911 is engaged by the urging force of the urging member. 831 is engaged. As a result, the duplex conveyance path unit 800 and the sheet conveyance belt unit 600 are attached to the apparatus main body 110.

According to the above, the following effects can be obtained in the present embodiment.
By attaching and detaching the paper transport belt unit 600 from the outlet 112 of the paper feed tray 200, work for disconnecting the connection between each process cartridge 500 and the drive source on the apparatus main body 110 side and work for removing the heavy drawer 520 from the apparatus main body 110 are performed. Since it becomes unnecessary, the maintenance work of the paper transport belt unit 600 can be simplified.

  Since the sheet feeding tray 200 that is slidable and detachable with respect to the apparatus main body 110 is adopted as the sheet storage unit, the sheet P is simply removed together with the sheet feeding tray 200 without removing the sheet P from the sheet feeding tray 200. Thus, the maintenance space S1 can be easily formed. In other words, in the form in which the sheet storage unit is integrally formed as a part of the apparatus main body, it is necessary to remove all the sheets from the sheet storage unit, and therefore the number of sheets is too large to hold all the sheets together. However, in this embodiment, such work is not necessary, so that the maintenance space S1 can be easily formed.

  Since the paper conveyance belt unit 600 is supported by the support arm 920 of the double-sided conveyance path unit 800, the double-sided conveyance path unit 800 and the paper conveyance belt unit 600 can be operated together, and the maintenance of the paper conveyance belt unit 600 can be further improved. It can be done easily.

  Since the double-sided conveyance path unit 800 and the paper conveyance belt unit 600 can be held together by a single locking mechanism 910, the number of parts is reduced compared to the case where a locking mechanism is provided for each of the double-sided conveyance path unit and the paper conveyance belt unit. can do.

  Since the swing end (front end) of the double-sided conveyance path unit 800 is disposed on the outlet 112 side, the upper side of the double-sided conveyance path unit 800 inclined obliquely after the paper conveyance belt unit 600 is removed from the apparatus main body 110. Faces the outlet 112. Therefore, if the upper portion of the frame 830 of the duplex conveyance path unit 800 is open, for example, even if the paper P is clogged between the internal return rollers 820, the duplex conveyance path unit 800 is pulled from the apparatus main body 110 without being removed. Jam processing can be easily performed by putting a hand through the outlet 112. Further, for example, when dust or the like adheres to the return roller 820 (especially the return roller 820 disposed on the front side), the return roller 820 can be easily cleaned by inserting a cleaning tool from the outlet 112. It can be carried out.

  Contrary to the present embodiment, when the front end (end portion on the outlet 112 side) of the double-sided conveyance path unit 800 is used as the swing center of the double-sided conveyance path unit 800, the rear side (drawer outlet) of the apparatus main body 110 is used. However, according to the structure of this embodiment, since the outlet 112 of the paper feed tray 200 can be used as the maintenance opening, the structure can be simplified. be able to.

  Since the swing end (front end) of the paper transport belt unit 600 is disposed on the outlet 112 side, when the paper transport belt unit 600 is tilted downward together with the duplex transport path unit 800, the upper surface of the paper transport belt unit 600 is pulled. It faces the exit 112 side. Accordingly, it is possible to easily perform jam processing between the sheet conveyance belt unit 600 and each photosensitive drum 510, cleaning of the belt 610, and the like without having to bother to remove the sheet conveyance belt unit 600 from the apparatus main body 110.

  Contrary to the present embodiment, when the front end (end portion on the outlet 112 side) of the paper transport belt unit 600 is the swing center of the paper transport belt unit 600, the rear side (drawer port) of the apparatus main body 110 is used. However, according to the structure of this embodiment, since the outlet 112 of the paper feed tray 200 can be used as the maintenance opening, the structure can be simplified. be able to.

  Since the paper transport belt unit 600 can be attached to and detached from the apparatus main body 110 while being guided by the guide groove 160, interference between the paper transport belt unit 600 and other members (such as the photosensitive drum 510 and the double-sided transport path unit 800) is suppressed. Can do.

  Since the rear protrusion 643 which is the swing center portion of the paper transport belt unit 600 is supported and guided by the guide groove 160, a guide for guiding the paper transport belt unit 600 and a member that supports the paper transport belt unit 600 so as to be swingable. The structure can be simplified as compared with the structure in which the members are provided separately.

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 embodiment, the paper conveyance belt unit 600 that conveys the paper P is used as the belt unit, and the double-sided conveyance path unit 800 for double-sided conveyance is adopted as the conveyance path unit. However, the present invention is limited to this. is not. For example, as shown in FIG. 6A, an intermediate transfer belt unit 601 on which an image is formed by each process cartridge 500 (image forming unit) is adopted as a belt unit, and the paper P inserted manually is conveyed. Therefore, the manual feed path unit 801 may be adopted as the transport path unit. Here, in FIG. 6 and FIG. 7, those having substantially the same structure / function as those of the above embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 6A, the intermediate transfer belt unit 601 is arranged to face the lower side of each process cartridge 500, and the manual feed path unit 801 includes the intermediate transfer belt unit 601 and the paper feed tray 201. It is arranged between. Here, the paper feed tray 201 is different from the above embodiment only in that the position of the handle portion 210 is provided on the side opposite to the paper feed roller 310 and the like, and other structures are substantially the same as those of the above embodiment. ing.

  The intermediate transfer belt unit 601 has substantially the same structure as the above embodiment, but differs from the above embodiment in that each transfer roller 650 functions as a primary transfer roller that transfers a toner image from each photosensitive drum 510 to the belt 610. Is different. The toner image transferred to the belt 610 is transferred onto the paper P by a secondary transfer roller 670 disposed adjacent to the rear of the belt 610.

  Further, the manual feed path unit 801 has been transported by a plurality of pairs of transport rollers 821 that transport the paper P inserted from the manual feed port 171 formed on the front wall of the apparatus main body 170 backward, and the transport rollers 821. A guide member 811 for guiding the paper P between the secondary transfer roller 670 and the belt 610 is provided.

  As shown in FIG. 6B, the intermediate transfer belt unit 601, the manual feed path unit 801, and the apparatus main body 170 include a front protrusion 642, a rear protrusion 643, an engagement protrusion 831, and the like, as shown in FIG. A holding mechanism 900 (lock mechanism 910 and support arm 920), a retraction mechanism 150, a guide groove 160, and the like are provided.

  Also in this embodiment, as shown in FIG. 6B, after removing the paper feed tray 201 from the apparatus main body 170, the manual feed path unit 801 is swung downward as shown in FIG. 7A. Accordingly, the upper surface of the intermediate transfer belt unit 601 faces the outlet 112, and jam processing or the like can be performed. Furthermore, from this state, as shown in FIG. 7B, the intermediate transfer belt unit 601 is taken out from the outlet 112, so that the intermediate transfer belt unit 601 can be replaced, jammed in the manual feed path unit 801, or the like. It can be performed.

  In the above-described embodiment, a structure in which the belt unit can be completely removed from the apparatus main body is employed. However, the present invention is not limited to this, and the belt unit may be configured to simply tilt. Even in this case, it is possible to perform jam processing between the belt unit and each photosensitive drum.

  In the above-described embodiment, a paper feed tray that can be attached to and detached from the apparatus main body is used as the sheet storage portion. However, the present invention is not limited to this, and the sheet storage portion may be formed so as not to be removable as a part of the apparatus main body. . Even in this case, if the recording sheet is taken out from the sheet storage portion, the belt unit can be retracted into the taken-out space for maintenance.

  In the above embodiment, a mechanism for retracting the conveyance path unit while rotating the conveyance path unit is employed as the retraction mechanism. However, the present invention is not limited to this, and for example, a mechanism for sliding the conveyance path unit downward is employed as the retraction mechanism. Also good.

  In the above-described embodiment, the mechanism that indirectly holds the belt unit via the transport path unit is the holding mechanism (the lock mechanism 910 and the support arm 920). However, the present invention is not limited to this, and for example, the belt unit is directly attached. The holding mechanism may be a holding mechanism.

  In the above embodiment, the lock mechanism 910 having the hook 911 is adopted. However, the present invention is not limited to this. For example, a pin that moves forward and backward with respect to the transport path unit and the transport path unit are formed, and the pin is fitted. You may employ | adopt as a locking mechanism.

  In the above embodiment, the side frame 114 in which the guide groove 160 is formed is used as the guide member. However, the present invention is not limited to this, and for example, a rib-shaped guide rail fixed to the inner surface of the side frame is used as the guide member. May be. Further, the guide member may be configured to support and guide a portion other than the swing center portion instead of supporting the swing center portion of the belt unit as in the embodiment.

  The drawer 520 may have a structure that can be detached from the apparatus main body 110, or a part of the drawer 520 that is pulled out and held while being engaged with the apparatus main body 110 can be removed from the apparatus main body 110. It may be configured such that it cannot be completely removed, that is, cannot be separated. The present invention is particularly effective when the drawer 520 has a structure that cannot be separated from the apparatus main body 110.

In the above-described embodiment, the present invention is applied to the color printer 100. 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 process cartridge 500 including the photosensitive drum 510 is used as the image forming unit. However, the present invention is not limited to this, and for example, an image forming unit including a belt-like photoconductor is used as the image forming unit. Also good.

DESCRIPTION OF SYMBOLS 100 Color printer 110 Apparatus main body 112 Outlet 150 Retraction | saving mechanism 200 Paper feed tray 500 Process cartridge 600 Paper conveyance belt unit 620 Drive roller 630 Followed roller 640 Frame 641 Handle part 642 Front protrusion 643 Rear protrusion 660 Belt surface 800 Both sides conveyance path unit 810 Guide member 820 Return roller 830 Frame 831 Engagement protrusion 832 Handle portion 900 Holding mechanism 910 Lock mechanism 911 Hook 920 Support arm P Paper S1 space S2 space

Claims (10)

An image forming apparatus in which an image forming unit and a belt unit are disposed opposite to each other in the apparatus main body,
A conveyance path unit that is disposed on the opposite side of the image forming unit across the belt unit and conveys the recording sheet along the belt surface of the belt unit;
A sheet storage unit disposed below the transport path unit and configured to store a recording sheet;
A retracting mechanism for retracting the transport path unit in a space in which the sheet storage unit is disposed;
A holding mechanism for detachably holding the belt unit to the apparatus main body,
The image forming apparatus, wherein the belt unit is displaceable to a space in which the sheet storage unit is disposed through a space in which the conveyance path unit retracted by the retracting mechanism exists.   The image forming apparatus according to claim 1, wherein the sheet accommodating portion is slidable with respect to the apparatus main body to be detachable.   The image forming apparatus according to claim 1, wherein the transport path unit includes a support portion that supports the belt unit. The holding mechanism is
The image forming apparatus according to claim 3, further comprising a lock mechanism that holds the transport path unit in the apparatus main body, and configured to hold the belt unit via the transport path unit.   The transport path unit is swingably supported by the apparatus main body so that one end side is a swing center and the other end is a swing end, and the other end is disposed on an opening side for taking out a recording sheet. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The belt unit is swingably supported by the apparatus main body so that one end side is a swing center and the other end is a swing end, and the other end is disposed on an opening side for taking out a recording sheet. The image forming apparatus according to claim 5. The belt unit is configured to be detachable from the apparatus main body through the opening,
The apparatus main body is provided with a guide member for guiding the belt unit to pull out the belt unit to the outside of the apparatus main body or to mount the belt unit from the outside of the apparatus main body to the inside. The image forming apparatus according to claim 6.   The image forming apparatus according to claim 7, wherein the guide member is configured to support and guide a swing center portion of the belt unit. The belt unit is a paper conveyance belt unit that conveys a recording sheet placed on the image forming unit side,
The image forming apparatus according to claim 1, wherein the conveyance path unit is a double-sided conveyance path unit for double-sided conveyance. The belt unit is an intermediate transfer belt unit on which an image is formed by the image forming unit,
The image forming apparatus according to claim 1, wherein the transport path unit is a manual transport path unit for transporting a manually inserted recording sheet.

Images