JP4807109B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus having a plurality of detachable units, and more particularly to an image forming apparatus having a plurality of detachable units including a user replaceable unit.
In this specification, “removable” means not only the case where it can be detached without requiring any special operation, but is normally used with a lock or screw fixed, and the screw or the like is removed at the time of replacement. And a detachable configuration.

Some conventional electrophotographic image forming apparatuses are configured such that constituent members are unitized and detachable for easy assembly and maintenance work. Such units include, for example, a toner cartridge that is replaced to replenish consumables such as toner, and a belt module or drum unit that replaces consumable parts that wear out over time, such as a belt or drum. is there.
A general detachable unit has a frame body, components are mounted on the frame body of the unit, and a guided portion formed in the frame body is provided in a housing (frame) of the image forming apparatus. It is configured to be attached and detached while being guided by a guide member (guide rail).

The following prior arts (J01) to (J03) are known as techniques relating to a detachable unit having such a configuration.
(J01) Technology described in Patent Document 1 (Japanese Patent Laid-Open No. 6-175547) Patent Document 1 describes an endless photoconductor belt and a plurality of belt support members (drive rollers (supporting rollers)) that rotatably support the photoconductor belt. 11), a driven roller (12), etc.) and a detachable unit (belt module) having a frame (photosensitive belt case (70)) for supporting the belt support member, a guided member (sliding member ( 71)), and a belt module can be attached to and detached from the image forming apparatus by guiding a guided member to a guide rail (61) supported by the image forming apparatus main body.

(J02) Technology described in Patent Document 2 (Japanese Patent Laid-Open No. 2000-187399) In Patent Document 2, a receiving frame (400) is slidable by a guide rail (401) with respect to an image forming apparatus main body (300). The intermediate transfer belt (TU) is detachably supported by the receiving frame (400).
(J03) Technology described in Patent Document 3 (Japanese Patent Application Laid-Open No. 2003-50527) Patent Document 3 describes an upper casing that holds a cleaning blade (51) as a cleaner for an image carrier (photosensitive member or intermediate transfer member). 52) and a lower casing (56) that holds a conveying screw (54) that conveys the collected waste toner, and the lower casing (56) is fixedly supported by the image forming apparatus main body (1), A technique is described in which the upper casing (52) is guided by the guide portion (57) of the lower casing (56) and is detachable from the main body of the image forming apparatus, thereby facilitating replacement of the cleaning blade.
Patent Document 3 also describes a cleaning device (50) having a casing (59) guided by a cleaning device rail (60).

JP-A-6-175547 (FIGS. 1 and 3) JP 2000-187399 A (“0083” to “0154”, FIGS. 2 to 15) JP 2003-50527 A (“0014” to “0015”, “0047” to “0049”, “0054”, FIGS. 2 and 8)

(Problems of conventional technology)
As in the prior arts (J01) to (J03), a guide member (guide rail) that guides a guided portion of the unit is provided for each unit that is attached to and detached from the image forming apparatus main body. That is, in the prior arts (J01) to (J03), it is necessary to install a guide member in the image forming apparatus main body for each unit to be attached and detached.
However, when such a guide member is provided, an extra space (space) for installing the guide member is required and the cost is increased, and it is difficult to reduce the size and cost of the image forming apparatus. There's a problem.

  Further, in order to attach and detach the unit, an opening through which the unit passes is necessary in the frame of the image forming apparatus, so that the strength of the frame becomes a problem. Therefore, in consideration of the strength of the entire image forming apparatus, it is desirable that the opening be as small as possible. In order to attach and detach the unit without damaging the small opening, the guide member may be configured to reliably guide. desirable.

In view of the above circumstances, the present invention has the following contents (O01) and (O02) as technical problems.
(O01) Reduce the number of guide members.
(O02) To reliably guide the detachable unit to a predetermined position.

Next, the present invention that solves the above problems will be described. In order to facilitate correspondence with the constituent elements of the embodiments described later, the constituent elements of the present invention are enclosed in parentheses. I will add that.
The reason why the present invention is described in correspondence with the reference numerals of the embodiments described later is to facilitate the understanding of the present invention, and not to limit the scope of the present invention to the embodiments.

(First invention)
In order to solve the technical problem, the image forming apparatus of the first invention is
A first unit (BM) having a first guided portion (25) guided by the first guide member (18), and a second guided portion guided by the second guide member (16, 17). A detachable unit (BM + CLU) having a second unit (CLU) having (81b, 81c) ;
With
The detachable unit (BM + CLU) is guided by the second guide member (16, 17) when only the second unit (CLU) is detached from the image forming apparatus main body (U1) and is guided by the second unit (16, 17). When only the CLU) is attached / detached and the first unit (BM) is attached / detached to / from the image forming apparatus main body (U1), the first guide member (18) and the second guide member (16, 17). The first guided portion (25) and the second guided portion (81b, 81c) are guided by and attached to and detached from the second unit (CLU).
The first unit (BM) includes the first guided portion (25) and an endless intermediate transfer belt (B) on which an image transferred to the medium (S) is transferred from the image carrier (PR) to the surface. ) And a belt support member (Rd, T1, Rf, Rt, T2a) that rotatably supports the intermediate transfer belt (B), and the belt support member (BM). Rd, T1, Rf, Rt, T2a) are supported detachably along the axial direction of the rotation axis,
The second unit (CLU) includes the second guided portion (81b, 81c) and a cleaning blade (CLB) that cleans the surface of the belt that contacts and rotates with the surface of the intermediate transfer belt (B). It is constituted by a cleaner unit (CLU) and is detachably supported along the axial direction, and has a member (93) for contacting and separating the cleaning blade (CLB) and the intermediate transfer belt (B). ,
In a state where the member (93) for contacting and separating the cleaning blade (CLB) and the intermediate transfer belt (B) is moved to a position where the cleaning blade (CLB) is separated from the intermediate transfer belt (B). The cleaner unit (CLU) and the belt module (BM) can be connected and disconnected, and the cleaning blade (CLU) and the belt module (BM) are connected in the state where the cleaner blade (BM) is connected. CLB) and the intermediate transfer belt (B) can be brought into contact with each other,
The second guide portion (16, 17) is disposed on the opposite side of the cleaner unit (CLU) from the belt module (BM), and the belt module of the second guided portion (81b, 81c). The cleaner unit (CLU) is guided in contact with the (BM) side surface and is restricted from moving to the belt module (BM) side.

(Operation of the first invention)
In the image forming apparatus of the first invention having the above-described constituent elements, the first guide member (18) and the second guide member (16, 17) are supported by the image forming apparatus main body (U1). The detachable unit (BM + PL + CLU) is guided by the first unit (BM) having the first guided portion (25) guided by the first guide member (18) and the second guide member (16, 17). A second unit (CLU) having a second guided portion (81b, 81c). When only the second unit (CLU) is attached / detached from the image forming apparatus main body (U1), only the second unit (CLU) is attached / detached by being guided by the second guide member (16, 17). The When the attachment / detachment unit (BM + PL + CLU) is attached / detached to / from the image forming apparatus main body (U1), the first guide member (18) and the second guide member (16, 17) are used for the first cover. The guide portion (25) and the second guided portion (81b, 81c) are guided and detached.
Therefore, in the image forming apparatus of the first invention, the second guide member (16, 17) and the second guided portion (81b, 81c) serve as a guide and attachment / detachment unit (BM + PL + CLU) when the second unit (CLU) is attached / detached. ) Used as a guide when attaching and detaching the whole. As a result, the guide member and the guided portion can be reduced as compared with the case where the guide member and the guided portion are provided for each unit, and the first unit (BM) and the second unit (CLU) are placed at predetermined positions. Can be securely guided and installed.

In the image forming apparatus of the first invention , the first unit (BM) includes an endless intermediate transfer belt (B ) on which an image transferred to the medium (S) is transferred from the image carrier (PR) to the surface. ) And a belt support member (Rd, T1, Rf, Rt, T2a) that rotatably supports the intermediate transfer belt (B). The second unit (CLU) is constituted by a cleaner unit (CLU) having a cleaner (CLB) that contacts the surface of the intermediate transfer belt (B) and cleans the surface of the rotating belt (B).
The first unit (BM) and the second unit (CLU) are detachably supported along the axial direction of the rotation shaft of the belt support member (Rd, T1, Rf, Rt, T2a).
In addition, the member (93) for contacting and separating the cleaning blade (CLB) and the intermediate transfer belt (B) has moved to a position where the cleaning blade (CLB) is separated from the intermediate transfer belt (B). The cleaner unit (CLU) and the belt module (BM) can be connected and disconnected, and the cleaner unit (CLU) and the belt module (BM) are connected in the state where the cleaning is performed. The blade (CLB) and the intermediate transfer belt (B) can be brought into contact with each other.
Further, the second guide portion (16, 17) is disposed on the opposite side of the cleaner unit (CLU) from the belt module (BM), and the second guided portion (81b, 81c) Guide and contact the belt module (BM) side surface and restrict the cleaner unit (CLU) from moving to the belt module (BM) side.

The above-described present invention has the following effects (E01) and (E02).
(E01) The number of guide members can be reduced.
(E02) The detachable unit can be reliably guided to a predetermined position.

Next, specific examples (examples) of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as the front side, the rear side, the right side, the left side, the upper side, the lower side, or the front side, the rear side, the right side, the left side, the upper side, and the lower side, respectively.
In the figure, “•” in “○” means an arrow heading from the back of the page to the front, and “×” in “○” is the front of the page. It means an arrow pointing from the back to the back.
In the following description using the drawings, illustrations other than members necessary for the description are omitted as appropriate for easy understanding.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention.
In FIG. 1, an image forming apparatus (digital copying machine) U according to the first embodiment includes an image forming apparatus main body U1 and an automatic document feeder U2. The image forming apparatus main body U1 includes an IOT (image output terminal) and an IIT (image input terminal, that is, an image reading unit).
The automatic document feeder U2 is supported on the platen glass PG on the top surface of the IIT.
A sheet discharge tray TRh is provided between the upper surface of the IOT and the upper IIT.

In FIG. 1, the automatic document feeder U2 has a document feed tray TG1 on which a plurality of documents Gi to be copied are stacked. Each of the plurality of documents Gi placed on the document feed tray TG1 is sequentially passed through a copy position on the platen glass PG and discharged to the document discharge tray TG2. The automatic document feeder U2 can be rotated with respect to the upper surface of the platen glass PG by a hinge shaft (not shown) provided in the rear end portion (−X end portion) extending in the left-right direction. When a person puts it on the platen glass PG by hand, it is rotated upward.
The image forming apparatus main body U1 has a UI (user interface) through which a user inputs an operation command signal such as copy start.

An exposure optical system A for reading a document image is disposed below the transparent platen glass PG.
Reflected light from a document conveyed on the upper surface of the platen glass PG by the automatic document feeder U2 or a document (not shown) manually placed on the platen glass PG is passed through the exposure optical system A to a CCD ( It is converted into an electrical signal by a solid-state imaging device).
The IPS (image processing system) converts RGB electrical signals input from the CCD into image data and temporarily stores them, and the image data is used as laser drive circuit DL as image data for forming a latent image at a predetermined timing. Output to.
The laser drive circuit DL outputs a laser drive signal to the ROS (latent image forming apparatus) according to the input image data. The ROS emits a laser beam (image writing light) L for image writing in accordance with a laser drive signal. The operation of the UI (user interface), IPS and laser drive signal output device DL, and a power supply circuit E for applying a bias voltage to the developing roll Ga and transfer roll Rt described later are controlled by a controller C.

The rotationally driven image carrier (photosensitive member) PR disposed above the ROS is uniformly charged by the charging roll CR and then the ROS (latent image forming apparatus) at the latent image writing position Q1. ) Is exposed and scanned by the laser beam L to form an electrostatic latent image. When forming a full-color image, electrostatic latent images corresponding to four color images of K (black), Y (yellow), M (magenta), and C (cyan) are sequentially formed. Only the electrostatic latent image corresponding to the (black) image is formed.
The surface of the image carrier PR on which the electrostatic latent image is formed rotates and moves sequentially through the development area Q2 and the primary transfer area Q3.

A rotary developing device G is arranged above the ROS. The rotary developing device G develops four colors of K (black), Y (yellow), M (magenta), and C (cyan) that sequentially rotate and move to the developing region Q2 as the rotation shaft Ga rotates. The units GK, GY, GM, and GC are included. The developing devices GK, GY, GM, GC of the respective colors have developing rolls GRk, GRy, GRm, GRc that convey the developer to the developing area Q2, and are on the image carrier PR that passes through the developing area Q2. The electrostatic latent image is developed into a toner image.
The developing containers of the developing units GK, GY, GM, and GC are configured to be supplied with toner of each color from toner replenishing cartridges TCk, TCy, TCm, and TCc, respectively. As such a rotary developing device, various configurations conventionally known (see, for example, JP-A-12-131942, JP-A-12-231250, etc.) can be employed.

FIG. 2 is an enlarged explanatory view of a main part of the image carrier and the intermediate transfer belt portion.
1 and 2, an endless intermediate transfer belt B is disposed on the left side of the image carrier PR. The intermediate transfer belt B includes a drive roll Rd for preventing rotation and meandering of the intermediate transfer belt (preventing meandering by a rib guide attached to the drive roll), and a primary transfer roll to which a primary transfer bias is applied. It is supported by T1, a sensor roll Rf facing a sensor (not shown) for detecting the rotation of the intermediate transfer belt B, a tension roll Rt for generating tension on the intermediate transfer belt B, and a backup roll T2a. Each of the rolls Rd, T1, Rf, Rt, T2a constitutes a belt support member (Rd, T1, Rf, Rt, T2a).
The intermediate transfer belt B is rotatably supported by the drive roll Rd, and rotates in the arrow Yb direction during an image forming operation.

When forming a full-color image, an electrostatic latent image of the first color is formed at the latent image writing position Q1, and a toner image of the first color is formed in the development region Q2. This toner image is electrostatically primary transferred onto the intermediate transfer belt B by the primary transfer roll T1 when passing through the primary transfer region Q3. Thereafter, similarly, the second, third, and fourth color toner images are sequentially superimposed and transferred onto the intermediate transfer belt B carrying the first color toner image in order, and finally, full-color multiplexing is performed. A toner image is formed on the intermediate transfer belt B.
In the case of forming a monochromatic monochromatic image, only one developing device is used, and the monochromatic toner image is primarily transferred onto the intermediate transfer belt B.
After the primary transfer, the surface of the image carrier PR is cleaned by an image carrier cleaner CL1. The image carrier PR from which the residual toner adhering to the surface is collected by the cleaner CL1 is recharged by the charging roll CR.

At a position facing the backup roll T2a, the secondary transfer roll T2b is disposed so as to be movable between a position separated from the backup roll T2a and a position in contact with the backup roll T2a. The backup roll T2a and the secondary transfer roll T2b constitute a secondary transfer device T2. A secondary transfer region Q4 is formed by a contact region between the backup roll T2a and the secondary transfer roll T2b.
A secondary transfer voltage having a polarity opposite to the charging polarity of the toner used in the developing device G is supplied from the power supply circuit E to the secondary transfer roll T2b, and the power supply circuit E is controlled by the controller C.

In FIG. 1, a paper feed tray TR1 (see FIG. 1) accommodates a recording sheet S to be transported to the secondary transfer region Q4, and extends in the front-rear direction on both the left and right sides (Y-axis direction both sides). Are supported so as to be movable along a pair of rails (not shown).
A paper feeding device K is supported on the paper feeding side upper portion of the paper feeding tray TR1. The pickup roll Rp of the paper feeder K takes out the recording sheets S stacked on the paper feed tray TR1 in accordance with the paper feed timing. The recording sheets S are separated one by one in a pressure contact area (separation area) of a separation roll Rs having a feed roll and a retard roll, and conveyed to the sheet conveyance path SH. The recording sheet S in the sheet conveyance path SH is conveyed to the registration roll Rr by a plurality of sheet conveyance rolls (takeaway rolls) Ra arranged along the sheet conveyance path SH. The registration roll Rr (see FIG. 1) conveys the recording sheet S to the secondary transfer area Q4 at a predetermined timing.
Further, the recording sheet S fed from the manual feed tray TR0 is also transported through the manual sheet transport path SH5, and the secondary transfer region Q4 by the sheet transport roll Ra and the registration roll Rr disposed along the sheet transport path SH. It is conveyed to.

The toner image on the intermediate transfer belt B is secondarily transferred onto the recording sheet S that passes through the secondary transfer region Q4. The toner remaining on the surface of the intermediate transfer belt B after the secondary transfer is collected and cleaned by the belt cleaner CLB.
The recording sheet S on which the unfixed toner image is transferred in the secondary transfer area Q4 is conveyed to the fixing area Q5 in a state where the toner image is not fixed, and a pair of fixing devices F of the fixing device F disposed in the fixing area Q5. The toner image is fixed by the rolls Fh and Fp. The recording sheet S on which the fixing toner image has been formed is guided by the sheet guide, conveyed to the sheet discharge roll R1, and discharged from the sheet discharge port Ha to the sheet discharge tray TRh.

A main body sheet reversing path SH2 connected to the sheet discharge port Ha is provided inside the printer U. A sheet reversing device U3 is mounted on the manual feed tray TR0. An optional sheet reversing path SH4 connected to the main body sheet reversing path SH2 is formed inside the sheet reversing device U3. Therefore, during double-sided printing, the sheet S on which the toner image is fixed in the fixing region Q2 passes through the main body sheet reversing path SH2 and the option sheet reversing path SH4, and is conveyed to the registration roll Rr. In the inverted state, the image is retransmitted to the secondary transfer area Q4.
The main sheet reversing path SH2 and the option sheet reversing path SH4 constitute a sheet reversing path (SH2 + SH4).
The pickup roll Rp, the separating roll Rs, the sheet conveying roll Ra, and the discharge roll R1 constitute a sheet conveying member (Rp, Rs, Ra, R1).

(Description of frame)
FIG. 3 is a front view of the frame of the image forming apparatus according to the first exemplary embodiment.
FIG. 4 is an enlarged view of a main part of an attaching / detaching portion of the intermediate transfer belt module and the photosensitive unit of the frame of FIG.
FIG. 5 is an explanatory perspective view of the frame shown in FIGS. 3 and 4 with the intermediate transfer belt module, the cleaner unit, and the positioning plate attached thereto.
3 to 5, the frame F of the image forming apparatus U according to the first exemplary embodiment includes column frames F <b> 1 that extend in the vertical direction and are arranged at four corners. A plate-like front frame (one-end-side frame) F2 is supported between the front columns F1a and F1b, and a rear disposed between the rear columns F1c and F1d so as to face the front frame F2. A frame (other end side frame) F3 is supported. A pair of opposed manual feed tray support frames F4 are supported on the left column F1, and IIT support members F6a to F6c that support IIT are supported on the left front, left rear, and right rear columns F1a, F1c, and F1d. Has been.
The front frame F2 and the rear frame F3 are connected by a plurality of tie plates F7 extending in the front-rear direction.
In addition, the front frame F2 of Example 1 is comprised with the sheet metal of plate | board thickness 1.2mm.

FIG. 6 is an explanatory diagram of a state in which the positioning plate is omitted from the state of FIG.
3 and 4, the front frame F2 includes a unit attachment / detachment opening 1 to which an intermediate transfer belt module, an image carrier unit, and a belt cleaner unit, which will be described later, formed in the upper left portion are attached and a toner supply cartridge TCy. A cartridge attaching / detaching port 2 for attaching / detaching TCk and an opening 3 for attaching a unit or member are formed.
In FIG. 4, plate fixing screw holes (positioning member fixing portions) 6, 7, 8, 9 are formed at four positions on the upper left, upper right, lower left, and lower right of the unit attachment / detachment opening 1 of the front frame F2. Yes. A plate positioning round hole 11 is formed at the lower right of the lower left plate fixing screw hole 8, and a plate positioning elongated hole 12 is formed at the right side of the lower right plate fixing screw hole 9. .
2, 3, and 6, a pair of upper and lower cleaner unit guide members (second guide members) 16 and 17 (see FIG. 6) are supported on the upper right portion inside the unit attachment / detachment opening 1. A belt unit guide member (first guide member) 18 is supported on the lower left portion of the unit attaching / detaching port 1.

3 and 4, the rear frame F3 includes a plurality of openings F3a in which a drive motor, a gear train, and the like are arranged, a module positioning hole (other end unit positioning portion) F3b, a module positioning slot (the other end). Side unit positioning portion F3c is formed.
5 and 6, an intermediate transfer belt module (belt unit, first unit) BM having an intermediate transfer belt B and belt support members (Rd, T1, Rf, Rt, T2a) through the unit attaching / detaching port 1; A cleaner unit (second unit) CLU in which the belt cleaner CLB is unitized, an image carrier (photoconductor) PR, a charging roll CR, and an image carrier unit (process unit) PU in which the image carrier cleaner CL1 is unitized. Are attached and detached.

(Description of intermediate transfer belt module)
FIG. 7 is a perspective explanatory view of the intermediate transfer belt module and the positioning plate.
FIG. 8 is an explanatory view showing a state in which the intermediate transfer belt module and the cleaner unit are pulled out from the state shown in FIG.
FIG. 9 is an explanatory view showing a state in which only the cleaner unit is pulled out from the state shown in FIG.
FIG. 10 is an explanatory perspective view of the intermediate transfer belt module and the cleaner unit as viewed obliquely from the front.
FIG. 11 is a perspective explanatory view of the intermediate transfer belt module and the cleaner unit as viewed obliquely from the rear.
12A and 12B are explanatory views of the intermediate transfer belt module and the cleaner unit. FIG. 12A is a perspective explanatory view of the cleaner unit as viewed obliquely from the rear. FIG. 12B is a perspective view of the intermediate transfer belt module as viewed from the oblique rear.

  6 to 12, the intermediate transfer belt module BM includes a plate-shaped front plate 21 and a rear plate 22. 11 and 12, a pair of upper and lower cleaner unit positioning convex portions 21a (only the upper side is shown in FIG. 12B) projecting forward is formed at the right end portion of the front plate, and the right end portion of the rear plate 22 is formed. A pair of upper and lower cleaner unit positioning holes 22a and 22b is formed in the upper portion. 6 to 10, a front cover member 23 is supported at the front central portion of the front plate 21, and a rear cover member 24 is supported at the rear central portion of the rear plate 22. Plate fixing portions 23a and 23b are formed at the left end portion and the right lower end portion of the front cover 23, and plate fixing screw holes (unit fixed portions) 23c and 23d are formed in the plate fixing portions 23a and 23b. ing.

11 and 12B, a guided portion (first guided portion) 25 that extends in the front-rear direction and protrudes downward is supported on the lower left ends of the front plate 21 and the rear plate 22.
The intermediate transfer belt module BM has a pair of positioning through shafts 26 and 27 that penetrate the members 21 to 24 in the front-rear direction. Positioning engagement portions (unit positioned portions) 26a, 26b, 27a, 27b are formed at the front end portion and the rear end portion of the positioning through shafts 26, 27, respectively. The positioning engagement portions 26b and 27b on the rear end side are supported in a state in which they are positioned by engaging (penetrating) with the module positioning holes F3b and the module positioning long holes F3c (see FIGS. 3 and 4) of the rear frame F3. The
Between the front plate 21 and the rear plate 22, the drive roll Rd, the sensor roll Rf, and the backup roll T2a extending in the front-rear direction are rotatably supported. 11 and 12, a belt drive coupling Rd1 is supported at the rear end of the drive roll Rd, and meshes with a coupling (not shown) of the image forming apparatus body U1 when the intermediate transfer belt module BM is mounted. Driving force is transmitted.

(Explanation of belt separation mechanism)
FIG. 13 is an explanatory diagram of the main part of the belt tensioning / releasing mechanism of the intermediate transfer belt module, and is an explanatory diagram at the belt tensioning position.
FIG. 14 is an explanatory view of the main part of the photosensitive member portion in FIG.
FIG. 15 is an explanatory view of a main part of the cam and the primary transfer roll portion of FIG.
FIG. 16 is an explanatory perspective view of FIG.
FIG. 17 is an explanatory view of the main part of the belt tensioning / releasing mechanism of the intermediate transfer belt module, and is an explanatory view at the belt tension releasing position.
FIG. 18 is an explanatory view of the main part of the photoconductor portion in FIG.
FIG. 19 is an explanatory view of a main part of the cam and the primary transfer roll portion of FIG.
FIG. 20 is a perspective explanatory view of FIG.

6 to 10, a handle shaft 31 that extends forward through the front cover member 23 is rotatably supported by the front plate 21 and the rear plate 22. 13 to 20, a tension release handle 32 for operation by a user is supported on the front end portion of the handle shaft 31.
13 to 20, a belt tension second cam 33 supported by the handle shaft 31 and rotatable integrally with the handle shaft 31 is disposed inside the front plate 21. The belt tension second cam 33 is formed at a position shifted in phase toward the belt eccentric cam portion 33a and the image carrier PR side (counterclockwise in FIG. 15) relative to the belt eccentric cam portion 33a. A cylindrical primary transfer roll eccentric cam portion 33b protruding forward.

A belt tension first cam 34 is supported on the left side of the belt tension second cam 33 of the front plate 21 so as to be rotatable about a rotation center 34a. The belt tension first cam 34 is constituted by an eccentric cam, and has a right side surface 34b that engages with the belt tension second cam 33 and a stud engagement surface 34c that is concavely curved on the upper right side. A tension spring support portion 34d is formed at the upper left end portion of the belt tension first cam 34.
A substantially L-shaped tension roll support arm 36 is supported on the left side of the belt tension first cam 34 so as to be rotatable about a rotation fulcrum 36a. The tension roll Rt is rotatably supported at one end of the tension roll support arm 36 opposite to the rotation fulcrum 36a. A tension spring support portion 36 b is formed at the L-shaped connecting portion of the tension roll support arm 36, and the tension spring support portion 34 d of the first belt tension cam 34 and the tension roll support arm 36. A tension spring 37 is mounted between the tension spring support portion 36b.

On the same axis as the rotation fulcrum 36a of the tension roll support arm 36, a primary transfer roll support arm 38 that rotatably supports the primary transfer roll T1 is supported rotatably about the rotation fulcrum 36a. . A spring connection portion 38a is formed on the upper left side of the primary transfer roll support arm 38, and the primary transfer roll support arm 38 carries an image between the spring connection pin 21a supported by the front plate 21. A primary transfer roll abutment spring 39 is attached to urge the body PR.
A cam formed on the right end portion of the primary transfer roll support arm 38 in a substantially triangular shape and engageable with the eccentric cam portion 33b for the primary transfer roll of the second cam 33 for belt tension. An engaging portion 38b is formed.
A belt separation shaft support portion 38c extending below the intermediate transfer belt B is formed at the lower right end portion of the primary transfer roll support arm 38. The belt separation shaft support portion 38c includes a belt separation shaft extending in the front-rear direction. A shaft 41 is supported.

At a position corresponding to the belt tension first cam 34 on the right side of the primary transfer roll support arm 38, a stud 38 d that engages with the stud engagement surface 34 c is located on the inner side (the belt tension first cam 34 side). ) Protruding and supported.
The members having the reference numerals 33 to 41 are arranged in a pair on the front and rear of the intermediate transfer belt module BM, and the members having the reference numerals 31 to 41 contact and separate the intermediate transfer belt B from the image carrier PR. The belt separation mechanism (31 to 41) of the first embodiment is configured.

  In the belt separation mechanism (31 to 41) of the first embodiment having the above-described configuration, the tension release handle 32 is normally held at the belt tension position shown in FIGS. At the belt tension position, the belt eccentric first cam 34 is pressed to the left by the belt eccentric cam 33a of the belt tension second cam 33, and the tension roll Rt is moved to the intermediate transfer belt B by the spring force of the tension spring 37. Apply tension to the tension. At this time, the primary transfer roll support arm 38 is held by pressing the lower surface of the cam engaging portion 38b downward by the primary transfer roll eccentric cam portion 33b. The primary transfer roll T1 is pressed against the image carrier PR with a predetermined pressing force via the intermediate transfer belt B by the spring force.

  When the image carrier unit PU is inserted / removed in the front-rear direction in order to replace the image carrier unit PU, the user rotates the tension release handle 32 and moves to the belt tension release position shown in FIGS. Let At the belt tension release position, the pressing of the belt tension first cam 34 by the belt eccentric cam portion 33a of the belt tension second cam 33 is released, and the tension on the intermediate transfer belt B by the tension roll Rt is released ( become weak). At this time, the belt tension second cam 33 rotates and the primary transfer roll eccentric cam portion 33b engages with the upper surface of the cam engagement portion 38b of the primary transfer roll support arm 38 to support the primary transfer roll. The right end of the arm 38 is rotated upward. When the right end portion of the primary transfer roll support arm 38 rotates upward, the primary transfer roll T1 is separated from the image carrier PR against the urging force of the primary transfer roll abutting spring 39, and 1 The belt separation shaft 41 supported by the next transfer roll support arm 38 contacts the surface of the intermediate transfer belt B to separate the intermediate transfer belt B from the image carrier PR. At this time, the stud engagement surface 34c of the belt tension first cam 34 is engaged with the stud 38d of the primary transfer roll support arm 38 and is held at the position shown in FIGS. Rt is held at the tension release position.

(Description of secondary transfer roll separation mechanism)
FIG. 21 is an enlarged explanatory view of a main part of a mechanism for bringing the secondary transfer device into contact with the intermediate transfer belt and a mechanism for bringing the cleaning blade of the cleaner unit into contact with and separated from the intermediate transfer belt module. In FIG. 21, the cleaner container and the like of the cleaner unit are not shown.
6, 10, and 21, a secondary transfer roll separation shaft 51 that passes through the front plate 21 and the rear plate 22 is supported on the left side of the intermediate transfer belt module BM. 11 and 12, a secondary transfer roll separation coupling 51a is supported on the rear end portion of the secondary transfer roll separation shaft 51, and the image forming apparatus main body U1 is mounted when the intermediate transfer belt module BM is mounted. The rotation is transmitted by meshing with a coupling (not shown).
In FIG. 21, an eccentric cam 52 for separating the secondary transfer roll is supported on the outside (front side) of the front plate 21 so as to be rotatable integrally with the shaft 51 for separating the secondary transfer roll.

  On the left side of the eccentric cam 52 for separating the secondary transfer roll, a substantially L-shaped first arm 53 for secondary contact of the secondary transfer roll rotates around a rotation fulcrum 53a (shared with the positioning through shaft 26 in the first embodiment). Supported as possible. A spring support portion 53b is formed at the lower right end portion of the first arm 53 for separating and contacting the secondary transfer roll, and between the spring support portion 53b and the spring support portion 54 supported by the front plate 21. A secondary transfer roll pressing spring 56 is mounted. A cam engagement member 57 that engages with the eccentric cam 52 for separating the secondary transfer roll is supported between the rotation fulcrum 53a and the spring support portion 53b. A second arm engagement member 58 is supported at the lower left end of the secondary transfer roll separating first contact arm 53.

On the lower left side of the secondary transfer roll separating / contacting first arm 53, a secondary transfer roll separating / contacting second arm 61 is supported so as to be rotatable about a rotation fulcrum 61a. A first arm engaging member 62 that engages with the second arm engaging member 58 is supported on the upper right end portion of the second arm 61 for separating and attaching the secondary transfer roll. A secondary transfer roll shaft engaging arm 63 that engages with the roll shaft of the secondary transfer roll T2b is supported on the upper left part of the second arm 61 for separating and attaching the secondary transfer roll.
The members denoted by reference numerals 52 to 63 are arranged in a pair on the front plate 21 and the rear plate 22 in the front-rear direction. The pair of front and rear members 52 to 63, the secondary transfer roll separating shaft 51, etc. The secondary transfer roll separation / contact mechanism (51-63) is configured.

In the image forming apparatus U according to the first exemplary embodiment, when the secondary transfer is performed in the image forming operation, the secondary transfer roll T2b is pressed against the backup roll T2a with a predetermined pressing force with the intermediate transfer belt B interposed therebetween. In the case of forming an image, while the four color images are stacked on the intermediate transfer belt B, the toner images of the first to third colors are stacked on the surface of the intermediate transfer belt B. The secondary transfer roll T2b is separated from the intermediate transfer belt B so that the toner image is not disturbed.
In the secondary transfer roll separating / contacting mechanism (51 to 63) of the first embodiment, when secondary transfer is performed, the secondary transfer roll pressing spring 56 is held at the roll pressing position shown in FIG. Thus, the second arm engaging member 58 of each secondary transfer roll attaching / detaching first arm 53 presses the first arm engaging member 62 of the secondary transfer roll attaching / detaching second arm 61 in the lower right direction. As a result, the secondary transfer roll shaft engaging arm 63 of the second arm 61 for separating / attaching the secondary transfer roll presses the roll shaft of the secondary transfer roll T2b toward the backup roll T2a with a predetermined pressing force. The transfer roll T2b is pressed against the backup roll T2a with a predetermined pressing force across the intermediate transfer belt B.

When forming the color image, when rotating the toner images of the first to third colors, the rotation is transmitted through the secondary transfer roll separation coupling 51a of the secondary transfer roll separation shaft 51, and the secondary transfer roll. The separation eccentric cam 52 rotates about 180 degrees from the state shown in FIG. Accordingly, the secondary transfer roll separating / contacting first arm 53 is rotated against the spring force of the secondary transfer roll pressing / contacting spring 56, and the secondary transfer roll separating / contacting by the second arm engaging member 58 is performed. The pressing of the second arm 61 is released. Accordingly, the pressure contact force of the secondary transfer roll T2b with respect to the intermediate transfer belt B is released. As a result, the secondary transfer roll T2b can be separated by a device for separating the secondary transfer roll T2b (not shown) provided on the secondary transfer roll T2b.
The secondary transfer roll shaft engaging arm 63 is disposed outside the unit attachment / detachment opening 1 of the front frame F2 in a no-load state, and is disposed at a position that interferes with the front frame F2 when the unit is attached / detached (FIG. 5) is the same direction as the direction in which the secondary transfer roll pressing spring 56 is urged, so that the operator can rotate inward (side approaching the intermediate transfer belt B) with a weak force. Therefore, the secondary transfer roll shaft engagement arm 63 can be easily moved to a position where it does not interfere with the front frame F2 (see FIG. 6), and the burden during the attaching / detaching operation can be reduced.

(Description of cleaning blade automatic separation mechanism)
In FIG. 21, a cleaning blade separation shaft 71 that penetrates the front plate 21 and the rear plate 22 is supported on the right side of the intermediate transfer belt module BM. A blade separation coupling 71a is supported at the rear end portion of the cleaning blade separation shaft 71. When the intermediate transfer belt module BM is mounted, the rotation is transmitted by meshing with a coupling (not shown) of the image forming apparatus main body U1. Is done.
On the outer side (front side) of the front plate 21, a blade separation eccentric cam 72 is supported so as to be integrally rotatable with the blade separation shaft 71.

On the left side of the blade separation eccentric cam 72, a substantially V-shaped blade separation contact arm 73 is supported so as to be rotatable about a rotation fulcrum 73a.
A cam engaging portion member 74 with which the blade separating eccentric cam 72 is engaged is supported on the upper left end portion of the blade separating arm 73. A blade separation pressing member 76 is supported on the upper right end portion of the blade separation arm 73.
The member denoted by reference numerals 71 to 76 constitutes the cleaning blade automatic separation mechanism of the first embodiment.

(Description of cleaner unit)
FIG. 22 is a perspective view of a main part of the front end portion of the cleaner unit.
FIG. 23 is an explanatory diagram of a main part of the front end portion of the cleaner unit, and is an explanatory diagram in a state where illustration of the cleaner front cover and the like is omitted.
5, 6, 8 to 12, and 21 to 23, the cleaner unit CLU according to the first embodiment includes a cleaner container 81 that stores waste toner collected from the intermediate transfer belt B. The cleaner container 81 has an opening 81a on the intermediate transfer belt B side. 8, 9, 11, 12, and 22, a pair of upper and lower cleaner unit guided portions extending in the front-rear direction guided by the cleaner unit guide members 16 and 17 are provided at the right end of the cleaner container 81. (Second guided portion) 81b and 81c are formed. Further, a positioning protrusion 81d (see FIG. 12A) that protrudes rearward is formed at the rear upper end of the opening 81a of the cleaner container 81, and positioning holes 81e, 81f (FIG. 12A, FIG. 22) is formed.

1, 2, and 23, a waste toner transport member 82 that transports waste toner in the cleaner container 81 to a waste toner collection container (not shown) is supported inside the cleaner container 81. A waste toner driving coupling 82a (see FIGS. 11 and 12A) is supported at the rear end of the waste toner conveying member 82, and meshes with a coupling (not shown) of the image forming apparatus main body U1 when the cleaner unit CLU is mounted. The rotation is transmitted.
21 to 23, a rotatable blade attaching / detaching shaft 83 is rotatably supported on the lower left end portion of the cleaner container 81. A positioning projection 83 a is formed at the rear end of the blade separating shaft 83. Accordingly, when the cleaner unit CLU is mounted on the belt module BM, the positioning protrusions 81d and 83a of the cleaner unit CLU are fitted into the cleaner unit positioning holes 22a and 22b of the belt module BM, and the cleaner unit CLU is positioned. The holes 81e and 81f are positioned by being fitted to the positioning protrusions 21a of the belt module.

  In FIG. 22, a substantially L-shaped blade support member 84 extending in the front-rear direction is fixedly supported on the blade attachment / detachment shaft 83. The blade support member 84 supports a cleaning blade 86 that contacts the intermediate transfer belt B and scrapes residual toner on the surface of the intermediate transfer belt B into the cleaner container 81. Spring connecting member support portions 84a extending obliquely upward are formed at both front and rear end portions of the blade support member 84, and a T-shaped spring connecting member 87 is supported by the spring connecting member support portion 84a. . The spring connecting portion 87 has a spring connecting portion 87 a that extends downward to the right. A blade pressure contact spring 88 is mounted between the spring connecting portion 87 a and the top wall of the cleaner container 81. Therefore, the cleaning blade 86 is pressed against the intermediate transfer belt B with a predetermined pressing force by the spring force of the blade pressing spring 88.

In FIG. 22, a pressed member 91 that can rotate integrally with the blade attaching / detaching shaft 83 is supported at the front end portion of the blade attaching / detaching shaft 83. On the upper left surface of the pressed member 91, a pressed surface 91 a is formed on which the blade separation pressing member 76 of the blade separation arm 73 contacts. At the upper right end portion of the pressed member 91, a manual separation engaged portion 91b protruding forward is formed.
A cleaner front cover 92 is supported on the front end side of the cleaner container 81. A blade separation handle 93 is supported on the cleaner front cover 92 so as to be rotatable about a rotation fulcrum 93a. The blade separation handle 93 has an arm portion 93b extending in the radial direction from the rotation fulcrum 93a and a semicircular arc-shaped gripping portion 93c formed at the tip of the arm portion 93b.

A snap-fit engagement recess 93d is formed at the right end of the arm portion 93b, and is snap-fitted by engaging with a snap-fit engagement protrusion 94 protruding forward from the front end surface of the cleaner front cover 92. .
The grip portion 93c is formed with a slit portion 93e extending in the circumferential direction. Further, a manual separation engaging portion 93f (see FIG. 23) protruding rearward is formed at the rear end of the blade separation handle 93, and the manual separation engaging portion 93f is the blade separation handle 93f. When 93 is moved from the normal position to the cleaner unit take-out position, it engages with the engaged portion 91b during manual separation.

A manual screw 96 for screwing the cleaner unit CLU to a positioning plate (described later) is supported at the front end of the cleaner front cover 92. The hand screw 96 has a hand grip portion 96 a that is gripped when the user manually rotates the hand screw 96. The hand gripping portion 96a is fitted into the slit portion 93e of the blade separation handle 93 in a completely screwed state, and closes a cover (not shown) of the image forming apparatus main body U1 if not in the fitted state. It is configured not to be able to.
The members denoted by reference numerals 91 to 96 constitute the cleaning blade manual separation mechanism (91 to 96) of the first embodiment.

Therefore, when the surface of the intermediate transfer belt B that has been subjected to the secondary transfer during the image forming operation is cleaned by the belt cleaner CLB configured as described above, the cleaning blade 86 that is pressed against the intermediate transfer belt B by the blade pressing spring 88 is used. Residual toner on the surface of the intermediate transfer belt B is scraped off.
On the other hand, in the state where the first to third color toner images are carried on the intermediate transfer belt B during the image forming operation, the cleaning blade 86 is used to prevent the toner images in the middle of forming the color image from being collected. Separate from. That is, the cleaning blade separation shaft 71 is rotated by the rotation transmitted through the blade separation coupling 71 a of the intermediate transfer belt module BM, and the blade separation eccentric cam 72 rotates the blade separation arm 73. As a result, the blade separation pressing member 76 presses the pressed surface 91a of the cleaner unit CLU, the blade separation contact shaft 83 rotates, and the cleaning blade 86 is intermediately transferred against the spring force of the blade pressure contact spring 88. Separate from belt B.

  When only the cleaner unit CLU is removed from the image forming apparatus main body U1, when the blade separation handle 93 is rotated, the manual separation engagement portion 93f is engaged with the manual separation engagement portion 91b and the blade separation handle is used. The shaft 83 is rotated and the cleaning blade 86 is separated from the intermediate transfer belt B. At this time, a force for returning the blade separation handle 93 is exerted by the spring force of the blade pressure contact spring 88. However, the cleaning blade 86 is locked by the handle lock by the snap-fit engagement concave portion 93d and the snap-fit engagement convex portion 94. Is held away from the intermediate transfer belt B. As a result, it is possible to prevent the cleaner unit CLU from being pulled out while the cleaning blade 86 is pressed against the intermediate transfer belt B, and it is possible to prevent the intermediate transfer belt B from being worn or scratched.

(Description of positioning plate)
FIG. 24 is an explanatory perspective view of the positioning plate of the first embodiment.
5, 7, and 24, a plate-like positioning plate (positioning member) PL is disposed between the front surface of the intermediate transfer belt module BM and the rear surface of the cleaner front cover 92 of the cleaner unit CLU. In addition, the positioning plate PL of Example 1 is configured by a sheet metal plate having a plate thickness of 1.6 mm that is higher in rigidity than the front frame F2.
In FIG. 24, a cleaner unit attaching / detaching port 101 for attaching / detaching the cleaner unit CLU is formed at the upper right portion of the positioning plate PL, and a process unit attaching / detaching port 102 for attaching / detaching the process unit PU at the lower left portion. Is formed.

A frame fixing first round hole 103 (positioning member fixed portion) is formed at the upper left end portion of the positioning plate PL. A frame fixing second round hole (positioning member fixed portion) 104 is formed in the upper right of the cleaner unit attaching / detaching port 101, and a frame fixing third round hole (positioning member covering portion) is formed in the lower left end of the positioning plate PL. (Fixed portion) 106 is formed. In addition, a fourth round hole for frame fixation (positioning member fixed portion) 107 is formed at the lower left of the cleaner unit attaching / detaching port 101.
A belt module fixing first round hole (unit fixing portion) 108 is formed in the upper left of the process unit attaching / detaching port 102, and a belt module fixing second round hole (unit fixing portion) is formed in the lower left of the cleaner unit attaching / detaching port 101. 109 is formed.

A module positioning hole (unit positioning portion) 111 through which the left positioning through shaft 26 of the intermediate transfer belt module BM passes and positions is formed above the first round hole 108 for fixing the belt module. A module positioning elongated hole (unit positioning portion) 112 through which the right positioning through shaft 27 of the intermediate transfer belt module BM passes is formed above the second round hole 109 for fixing the belt module.
On the right side of the module positioning long hole 112, the screw hole 113 for manual operation is formed in which the manual screw 96 of the cleaner unit CLU is screwed.
A frame positioning pin 114 protruding rearward is supported below the third round hole 106 for fixing the frame, and a frame positioning pin 115 protruding rearward is supported to the right of the fourth round hole 107 for fixing the frame. Has been.
Each of the round holes 103 to 109 is constituted by a through hole (so-called fool hole).

When the positioning plate PL is attached to the intermediate transfer belt module BM, the positioning through shafts 26 and 27 of the intermediate transfer belt module BM are passed through the module positioning hole 111 and the module positioning long hole 112 for positioning. In this state, belt fixing screws (unit fixing members) 116, 117 that pass through the belt module fixing round holes 108, 109 and are screwed into the plate fixing screw holes 23c, 23d of the intermediate transfer belt module BM (see FIG. 5). Thus, the positioning plate PL is fixed to the intermediate transfer belt module BM.
When the positioning plate PL is attached to the front frame F2, the frame positioning pins 114 and 115 are positioned through the plate positioning round holes 11 and the plate positioning long holes 12 of the front frame F2. In this state, frame fixing screws (positioning member fixing members) 121 to 124 that pass through the frame fixing round holes 103 to 107 and screw into the plate fixing screw holes 6, 7, 8, and 9 (see FIG. 5). Thus, the positioning plate PL is fixed to the front frame F2.
When the cleaner unit CLU is fixed to the image forming apparatus main body U1, after inserting the cleaner unit CLU, the hand screw 96 is manually rotated and the hand screw 96 is screwed into the hand screw hole 113, and the cleaner unit CLU is fixed. Is fixed to the positioning plate PL.

  That is, in the image forming apparatus U of Embodiment 1, the cleaner unit CLU is attached with the positioning plate PL attached to the front surface of the intermediate transfer belt module BM, and the screwing is released by rotating the hand screw 96. By doing so, only the cleaner unit CLU can be attached and detached. On the other hand, if the frame fixing screws 121 to 124 are removed while the cleaner unit CLU is fixed to the positioning plate PL with the hand screw 96, a detachable unit (BM + PL + CLU) comprising the intermediate transfer belt module BM, the positioning plate PL and the cleaner unit CLU. Can be attached and detached integrally.

(Operation of Example 1)
In the image forming apparatus U of Embodiment 1 having the above-described configuration, when the intermediate transfer belt module BM is mounted on the image forming apparatus main body U1, the rear end portions of the two positioning through shafts 26 and 27 are the image forming apparatus main body. It is supported in a state of being positioned at U1, and the front end portion is positioned by the positioning plate PL. In this state, the positioning plate PL passes through the belt module fixing round holes 108 and 109 and is fixed to the intermediate transfer belt module BM by screws screwed into the plate fixing screw holes 23c and 23d. The positioning plate PL is assembled as a reinforcing member of the image forming apparatus U because it passes through 103 to 107 and is fixed to the front frame F2 by screws screwed into the plate fixing screw holes 6, 7, 8, and 9. As a result, the belt module BM and the positioning plate PL can be used as a reinforcing member yesterday, and the strength of the frame of the image forming apparatus U can be increased. Therefore, the alignment (relative between the roll axes) of the belt support members (Rd, T1, Rf, Rt, T2a) that support the intermediate transfer belt B by the unevenness, flatness, etc. of the floor surface on which the image forming apparatus U is installed (Inclination) can be minimized. Therefore, it is possible to minimize the misalignment of the intermediate transfer belt B, which is a problem in the case of a low-cost frame.

Further, since the intermediate transfer belt module BM is positioned with respect to the front frame F2 via the positioning plate PL, other constituent members (image carrier unit PU and fixing device F, sheet conveying members (Rp, Rs, Ra, It is possible to keep the positional relationship with R1)) constant. That is, even if the image forming apparatus U is deformed (distorted) due to unevenness on the floor surface, the intermediate transfer belt B is positioned and the positioning plate PL fixed to the frame F2 follows the deformation. Compared with the case where B and the other members are individually deformed, it is possible to easily maintain the positional relationship between the members in a fixed relationship.
In particular, in the image forming apparatus U according to the first exemplary embodiment, the positioning plate PL is configured by a relatively high-rigidity sheet metal, so that the rigidity of the detachable unit (BM + PL + CLU) that can be integrally attached and detached can be increased. Distortion of the detachable unit (BM + PL + CLU) can be reduced. Accordingly, when the detachable unit (BM + PL + CLU) is attached to the front frame F2, the positioning and fixing can be surely performed, and the rigidity (strength) of the image forming apparatus U as a whole can be increased (reinforcement). it can). Further, in the belt module BM of the first embodiment, the through shafts 26 and 27 that penetrate the module BM are used. Therefore, compared to the case where a member that does not penetrate is used, the belt module BM is less likely to be distorted and the strength can be increased.

  In the image forming apparatus U according to the first embodiment having the above-described configuration, when the image carrier unit PU is replaced, the tension release handle 32 is rotated to rotate the intermediate transfer belt B and the primary from the image carrier PR. The transfer roll T1 can be separated, and the image carrier unit PU can be inserted and removed. Accordingly, it is possible to prevent the image carrier PR and the intermediate transfer belt B from being scratched. Further, since the tension release handle 32 is arranged at a position that prevents the movement of the image carrier unit PU in the axial direction (insertion / removal direction) at the normal belt tension position, the tension release handle 32 is rotated to rotate the image. The image carrier unit PU cannot be attached or detached unless the intermediate transfer belt B and the primary transfer roll T1 are separated from the carrier PR. Therefore, it is possible to reliably prevent the image carrier unit PU from being attached and detached without separating the intermediate transfer belt B and the primary transfer roll T1 from the image carrier PR, and it is possible to reliably prevent the scratches.

  Further, in the image forming apparatus U of Embodiment 1, when only the cleaner unit CLU is attached and detached, the blade separating handle 93 is rotated to separate the cleaning blade 86 from the intermediate transfer belt B. In this state, the hand screw 96 can be rotated to release the fixing with the positioning plate PL and to be detached. At this time, the cleaner unit CLU can be securely attached and detached at a predetermined position by the cleaner unit guided portions 81b and 81c being guided by the cleaner unit guide members 16 and 17, and can be attached and detached only by the cleaner unit CLU. can do. The cleaner unit CLU according to the first embodiment is configured so that the hand screw 96 cannot be rotated unless the blade separation handle 93 is rotated to release the contact between the cleaning blade 86 and the intermediate transfer belt B. Therefore, it is possible to prevent the cleaner unit CLU from being attached or detached while the cleaning blade 86 is in pressure contact with the intermediate transfer belt B. Further, in the cleaner unit CLU according to the first embodiment, since the hand grip portion 96a of the hand screw 96 is fitted to the slit portion 93e of the blade separation handle 93, it is determined whether the screwing is insufficient. The user can easily confirm whether or not the cleaner unit CLU is sufficiently fixed to the positioning plate PL.

  In the image forming apparatus U according to the first embodiment, the frame fixing screws 121 to 124 are removed while the tension release handle 32 is rotated to the tension release position and the cleaner unit CLU is fixed to the positioning plate PL by the hand screw 96. Thus, the detachable unit (BM + PL + CLU) having the intermediate transfer belt module BM, the positioning plate PL, and the cleaner unit CLU can be integrally detached. At this time, in the detachable unit (BM + PL + CLU), the guided portion 25 of the intermediate transfer belt module BM is guided by the belt unit guide member 18 and the guided portions 81b and 81c of the cleaner unit CLU are the cleaner unit guide members 16 and 17. By being guided by, it can be reliably guided and detached. As a result, it is possible to prevent the intermediate transfer belt B from being contacted with an internal member to form a scratch or the like. In particular, since the detachable unit (BM + PL + CLU) of the first embodiment is positioned and fixed by the positioning plate PL, the units BM and CLU can be mounted and detached while being positioned and reinforced.

Therefore, in the image forming apparatus U according to the first embodiment, the guided portions 81b and 81c of the cleaner unit CLU are used both as a guide for attaching / detaching the cleaner unit CLU alone and a guide for attaching / detaching the attach / detach unit (BM + PL + CLU). . As a result, space saving and cost reduction can be achieved as compared with the case where a guide member and a guided portion are provided for each unit, and the unit can be easily replaced and sufficient maintainability can be secured.
As a result, the intermediate transfer belt module BM can be attached / detached / replaced while the user can easily attach / detach / replace only the cleaner unit CLU with a space-saving and low-cost configuration.

(Example of change)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Examples of modifications of the present invention are illustrated below.
(H01) In the above-described embodiment, the copying machine as the image forming apparatus has been illustrated. However, the present invention is not limited to this, and a FAX, a printer, or a multifunction machine having all or a plurality of functions may be used. Further, the image forming apparatus is not limited to a color image forming apparatus, and may be configured by a monochrome image forming apparatus. The present invention is not limited to a so-called rotary image forming apparatus, and can be applied to an image forming apparatus such as a tandem type. is there.

(H02) In the above embodiment, the present invention is not limited to the detachable unit having the intermediate transfer belt module as the first unit and the cleaner unit as the second unit, and is applicable to the detachable unit having two detachable units. is there. For example, a process unit (attachment / detachment) having an image carrier cleaner unit (second unit) and an image carrier unit (first unit) when the image carrier cleaner can be individually attached to and detached from the image carrier. Unit) or a detachable unit having an image carrier unit (first unit) and a developing unit (second unit). In other words, the first unit is not limited to the belt module, and may be any detachable unit.

(H03) In the above-described embodiment, the intermediate transfer belt module is exemplified as the belt module. However, the belt transfer module is not limited to this, and can be applied to a conventionally known belt module such as a photoreceptor belt module, a paper transport belt module, and a transfer belt module. .
(H04) In the above-described embodiment, the positioning of the belt module BM and the rear frame F3 and the positioning of the belt module BM and the positioning plate PL are performed by providing unit positioned portions 26a, 26b, 27a, 27b that protrude toward the module BM. Although the hole (unit positioning portion) is provided on the rear frame F3 or the positioning plate PL side, it is also possible to provide a hole on the module side and a protrusion on the frame or plate side.
(H05) In the embodiment described above, it is desirable to use the through shafts 26 and 27 in order to increase the strength of the belt module BM. However, the present invention is not limited to this, and the unit positioned portion that protrudes outward from the plates 21 and 22 is used. It is also possible.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is an enlarged explanatory view of a main part of the image carrier and the intermediate transfer belt portion. FIG. 3 is a front view of the frame of the image forming apparatus according to the first exemplary embodiment. FIG. 4 is an enlarged view of a main part of an attaching / detaching portion of the intermediate transfer belt module and the photosensitive unit of the frame of FIG. FIG. 5 is an explanatory perspective view of the frame shown in FIGS. 3 and 4 with the intermediate transfer belt module, the cleaner unit, and the positioning plate attached thereto. FIG. 6 is an explanatory diagram of a state in which the positioning plate is omitted from the state of FIG. FIG. 7 is a perspective explanatory view of the intermediate transfer belt module and the positioning plate. FIG. 8 is an explanatory view showing a state in which the intermediate transfer belt module and the cleaner unit are pulled out from the state shown in FIG. FIG. 9 is an explanatory view showing a state in which only the cleaner unit is pulled out from the state shown in FIG. FIG. 10 is an explanatory perspective view of the intermediate transfer belt module and the cleaner unit as viewed obliquely from the front. FIG. 11 is a perspective explanatory view of the intermediate transfer belt module and the cleaner unit as viewed obliquely from the rear. 12A and 12B are explanatory views of the intermediate transfer belt module and the cleaner unit. FIG. 12A is a perspective explanatory view of the cleaner unit as viewed obliquely from the rear. FIG. 12B is a perspective view of the intermediate transfer belt module as viewed from the oblique rear. FIG. 13 is an explanatory diagram of the main part of the belt tensioning / releasing mechanism of the intermediate transfer belt module, and is an explanatory diagram at the belt tensioning position. FIG. 14 is an explanatory view of the main part of the photosensitive member portion in FIG. FIG. 15 is an explanatory view of a main part of the cam and the primary transfer roll portion of FIG. FIG. 16 is an explanatory perspective view of FIG. FIG. 17 is an explanatory view of the main part of the belt tensioning / releasing mechanism of the intermediate transfer belt module, and is an explanatory view at the belt tension releasing position. FIG. 18 is an explanatory view of the main part of the photoconductor portion in FIG. FIG. 19 is an explanatory view of a main part of the cam and the primary transfer roll portion of FIG. FIG. 20 is a perspective explanatory view of FIG. FIG. 21 is an enlarged explanatory view of a main part of a mechanism for bringing the secondary transfer device into contact with the intermediate transfer belt and a mechanism for bringing the cleaning blade of the cleaner unit into contact with and separated from the intermediate transfer belt module. FIG. 22 is a perspective view of a main part of the front end portion of the cleaner unit. FIG. 23 is an explanatory diagram of a main part of the front end portion of the cleaner unit, and is an explanatory diagram in a state where illustration of the cleaner front cover and the like is omitted. FIG. 24 is an explanatory perspective view of the positioning plate of the first embodiment.

Explanation of symbols

16, 17 ... second guide member,
18 ... 1st guide member,
25 ... 1st guided part,
81b, 81c ... second guided portion,
B ... Belt,
BM ... 1st unit, belt module,
BM + PL + CLU ... Detachable unit,
CLB ... Cleaner,
CLU ... 2nd unit, cleaner unit,
Rd, T1, Rf, Rt, T2a ... belt support member,
U1. Image forming apparatus main body.

Claims (1)

A first guide member and a second guide member supported by the image forming apparatus main body;
A detachable unit having a second unit having a first unit having a first guided portion which is guided by the first guide member, a second guided portion to be guided by the second guide member,
With
When only the second unit is attached to or detached from the image forming apparatus main body, the attachment / detachment unit is guided by the second guide member, and only the second unit is attached / detached, and the first unit is formed by the image formation. When attaching to and detaching from the apparatus main body, the first guided portion and the second guided portion are guided by the first guide member and the second guide member, and are integrally attached to and detached from the second unit.
The first unit includes the first guided portion , an endless intermediate transfer belt on which an image transferred to a medium is transferred from an image carrier to the surface, and a belt support that rotatably supports the intermediate transfer belt. And a belt module having a member, and is detachably supported along the axial direction of the rotation shaft of the belt support member,
The second unit is constituted by a cleaner unit including the second guided portion and a cleaning blade that contacts and rotates the surface of the intermediate transfer belt and rotates along the axial direction. Removably supported,
A member for contacting and separating the cleaning blade and the intermediate transfer belt;
The cleaner unit and the belt module can be connected to and disconnected from each other when the member that contacts and separates the cleaning blade and the intermediate transfer belt moves to a position where the cleaning blade moves away from the intermediate transfer belt. And in the state where the cleaner unit and the belt module are connected, the cleaning blade and the intermediate transfer belt can be brought into contact with each other.
The second guide portion is disposed on the opposite side of the cleaner unit from the belt module, and guides the second guided portion in contact with the surface of the second guided portion on the belt module side. An image forming apparatus characterized by restricting movement to a module side.

Images