JP5444600B2 - Belt-shaped member driving apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a belt-shaped member driving device and an image forming apparatus.

In a conventional image forming apparatus, an endless belt-like member such as a so-called medium transport belt or an intermediate transfer belt is used to transport a medium or to stack and temporarily hold a multicolor image. As such an image forming apparatus, techniques disclosed in Patent Documents 1 and 2 below are known.
In Japanese Patent Laid-Open No. 9-281770 as Patent Document 1, four photoconductors (6Y, 6M, 6C, 6K) are arranged in the horizontal direction, and each photoconductor (6Y, 6M, 6C, 6K) is sequentially recorded. In an image forming apparatus having a conveyance belt (20) for conveying a medium (S) so as to pass therethrough, photoreceptors (6Y, 6M, 6C) of three colors of yellow, magenta, and cyan and developing rollers (9Y, 9M, 9C). ) Or the like as a color image forming unit (A) so as to be integrally close to or separated from the conveyor belt (20). In the case of monochrome printing, the color image forming unit (A) is separated to allow color printing. In this case, a technique is described in which printing is performed by bringing the color image forming unit (A) into contact with the conveying belt (20). That is, in the technique described in Patent Document 1, color image formation is performed using a large and complicated mechanism in order to reduce wear of the photoconductors (6Y, 6M, 6C) of the color image forming unit (A) during monochrome printing. The unit (A) is moved up and down, and a large separation distance is taken to prevent contact between the conveyor belt (20) and the photosensitive members (6Y, 6M, 6C).

  In Japanese Patent Laid-Open No. 2000-352883 as Patent Document 2, four photoconductors (1a, 1b, 1c, 1d) are arranged horizontally, and each photoconductor (1a, 1b, 1c, 1d) is sequentially transferred to a transfer material. In the image forming apparatus having the transfer conveyance belt (9a) that conveys the toner so as to pass through, the outermost surface side of the transfer conveyance belt (9a), between each of the photosensitive members (1a, 1b, 1c, 1d) and the most upstream position The auxiliary transfer rollers (14a, 14b, 14c, 14d) are disposed on the upper side of the transfer auxiliary belt (14a, 14b, 14c, 14d). 9a) is separated from the photoreceptors other than black (1a, 1b, 1c), and the conveyance auxiliary rollers (14a, 14b, 14c, 14d) are separated from the transfer conveyance belt (9a) during color printing. Be to all the photoconductor (1a, 1b, 1c, 1d) is a technique for contacting to the transfer conveyor belt (9a) has been described. In the technique described in Patent Document 2, a strong load is applied by the conveyance auxiliary rollers (14a, 14b, 14c, 14d) to deform and bend the transfer conveyance belt (9a), so that the photoconductors (1a, 1b) other than black are used. 1c) and is transported in a state where the transport path for transporting the recording material is bent.

JP-A-9-281770 (“0035” to “0063”, FIGS. 1 and 4) JP 2000-352883 A (“0032” to “0037”, “0039” to “0049”, FIGS. 1 to 6)

  This invention makes it a technical subject to prevent a contact with a strip | belt-shaped member and the opposing member arrange | positioned facing a strip | belt-shaped member by simple structure.

In order to solve the technical problem, a belt-shaped member driving device according to claim 1 is provided.
An endless belt-like member whose inner surface is rotatably supported by a plurality of support members;
A belt-shaped member moving mechanism that moves the belt-shaped member close to and away from a facing member disposed to face the outer surface of the belt-shaped member;
A pressing member that presses the band-shaped member in contact with the outer surface of the band-shaped member in a state where the band-shaped member is separated from the facing member;
An urging member that urges the pressing member against the belt-shaped member;
With
The opposing member has an opposing member that approaches and separates from the belt-like member by movement of the belt-like member, and an opposing member that continues to contact before and after the movement of the belt-like member,
The band-shaped member moving mechanism is centered on a rotation center disposed on the opposite side with respect to the counter member that is close to and separated from the band-shaped member across the counter member that continues to contact before and after the movement of the band-shaped member. Moving the strip member relative to the opposing member;
The pressing member is disposed on the upstream side in the moving direction of the band-shaped member with respect to the opposing member that continues to contact before and after the movement of the band-shaped member, and outside the cleaning region of the cleaner that cleans the band-shaped member , The belt member is driven to rotate while being urged by the urging member and in contact with the belt-like member, and the belt-like member is contacted with the belt-like member and cleaned before and after the opposing member contacts and separates from the belt-like member. It is characterized by.

According to a second aspect of the present invention, in the belt-shaped member driving device according to the first aspect,
The support member disposed in a state in which the band-shaped member is pushed from the inner surface side toward the outer surface side;
The pressing member that presses the outer surface of the band-shaped member to the inner surface side with a force that is weaker than the force that pushes the band-shaped member to the outer surface side by the support member;
It is provided with.

According to a third aspect of the present invention, in the belt-shaped member driving device according to the first or second aspect,
The pressing member that moves integrally in response to the operation of approaching and separating from the facing member,
It is provided with.

In order to solve the technical problem, an image forming apparatus according to a fourth aspect of the present invention provides:
The opposing member composed of an image carrier that holds and rotates an image on the surface;
The endless belt-shaped member configured by a medium conveying member that rotates while holding the medium on the surface;
The support member configured by a transfer member that transfers an image of the surface of the image carrier to the medium;
The pressing member disposed on the outer side in the medium width direction of the medium held on the surface of the image holding body with respect to the medium width direction intersecting the medium moving direction;
It has the strip | belt-shaped member drive device in any one of Claim 1 thru | or 3 characterized by the above-mentioned.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect,
A transport member cleaner for cleaning the surface of the medium transport member in a cleaning region including the width of the image;
The pressing member disposed outside the cleaning region in the medium width direction; and
It is provided with.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect,
A plurality of the image holding bodies having an image holding body that approaches and separates from the belt-like member by movement of the belt-like member by the belt-like member moving mechanism, and an image holding body that continues to contact before and after the movement of the belt-like member;
The pressing member disposed in the vicinity of the image carrier that is close to and away from the belt-shaped member;
It is provided with.

According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect,
The image carrier that continues to contact before and after the movement of the belt-shaped member disposed on the downstream side of the image carrier that is close to and away from the belt-shaped member with respect to the medium transport direction of the medium transport member;
The pressing member disposed on the downstream side in the medium conveying direction of the image holding member that is close to and separated from the belt-shaped member;
It is provided with.

The invention according to claim 8 is the image forming apparatus according to any one of claims 4 to 6,
A plurality of the image holding bodies having an image holding body that approaches and separates from the belt-like member by the movement of the belt-like member by the belt-like member moving mechanism and the image holding body that continues to contact before and after the movement of the belt-like member are vertically moved. Arranged side by side,
The medium conveying direction of the medium conveying member is set in a direction from the lower side to the upper side, and the image holding body that continues to contact before and after the movement of the belt-like member is disposed at the uppermost position that is the most downstream in the medium conveying direction. It is characterized by being.

According to the first aspect of the present invention, it is possible to prevent the contact between the belt-shaped member and the facing member disposed to face the belt-shaped member with a simple configuration as compared with the case where the configuration of the present invention is not provided. it can.
According to invention of Claim 2, compared with the case where the structure of this invention is not provided, it can reduce that the shape of the strip | belt-shaped member pushed by a support member changes.
According to the third aspect of the present invention, compared to the case where the configuration of the present invention is not provided, the belt-shaped member can be reliably pressed before and after the proximity and separation, and contact of the belt-shaped member with the opposing member is prevented. it can.

According to the fourth aspect of the present invention, the contact between the medium carrying member or the medium held on the surface of the medium carrying member and the image holding body can be made with a simple structure as compared with the case where the structure of the present invention is not provided. Can be prevented.
According to invention of Claim 5, a cleaning area | region can be cleaned with a cleaner, and the outer side of a cleaning area | region can be cleaned with a pressing member.
According to the sixth aspect of the present invention, it is possible to reliably prevent the belt-like member from contacting the image carrier that is close to or separated from the belt-like member, as compared with the case where the configuration of the present invention is not provided.

According to the seventh aspect of the present invention, as compared with the case where the configuration of the present invention is not provided, the image carrier that is close to and away from the belt-like member is disposed on the downstream side in the medium conveyance direction, and the separation distance is relatively narrow. Contact between the image carrier and the belt-like member can be reliably prevented.
According to the eighth aspect of the present invention, as compared with the case where the configuration of the present invention is not provided, the contact between the medium conveyed in the vertical direction and the image carrier can be reliably prevented, and the medium can be conveyed stably. .

Next, examples which are specific examples of 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, a printer U as an example of the image forming apparatus according to the first exemplary embodiment of the present invention has a sheet feeding container TR1 in which a recording sheet S as an example of a medium on which an image is recorded is accommodated in a lower portion. A paper discharge section TRh is provided on the upper surface. An operation unit UI is provided at the top of the printer U.
In FIG. 1, the printer U according to the first embodiment includes an image forming apparatus main body U1 and an opening / closing section U2 that can be opened and closed around a rotation center U2a provided at the lower right end of the image forming apparatus main body U1. The opening / closing unit U2 performs an unillustrated open position for opening the interior of the image forming apparatus main body U1 in order to replace a process cartridge described later and to remove a jammed recording sheet S, and an image forming operation shown in FIG. It is configured to be movable between normal positions held at normal times.

  The printer U includes a control unit C that performs various controls of the printer U, an image processing unit GS whose operation is controlled by the control unit C, an image writing device driving circuit DL, a power supply device E, and the like. The power supply device E applies voltages to charging rollers CRy to CRk as an example of a charger described later, developing rollers G1y to G1k as an example of a developer holding member, and transfer rollers T1y to T1k as an example of a transfer device. .

The image processing unit GS converts print information input from an external image information transmission device or the like into latent images corresponding to four color images of K (black), Y (yellow), M (magenta), and C (cyan). The image information is converted into image information for image formation and output to the image writing device driving circuit DL at a predetermined timing. The image writing device driving circuit DL outputs a driving signal to the latent image writing device ROS according to the input image information of each color. The latent image writing device ROS emits laser beams Ly, Lm, Lc, and Lk as an example of image writing light for image writing of each color in accordance with a drive signal.
In FIG. 1, a toner image as an example of a visible image of each color of Y (yellow), M (magenta), C (cyan), and K (black) is formed on the right side of the latent image writing device ROS. Visible image forming apparatuses UY, UM, UC, UK as an example of an image recording unit are arranged.

FIG. 2 is an explanatory diagram of a visible image forming apparatus which is an example of a detachable body according to the first embodiment of the present invention.
In FIG. 2, a visible image forming apparatus UK for K (black) has a photoconductor Pk as an example of a rotating image carrier. Around the photosensitive member Pk, there are a charging roll CRk as an example of a charger, a developing device Gk that develops an electrostatic latent image on the surface of the photosensitive member into a visible image, a static eliminating member Jk that neutralizes the surface of the photosensitive member Pk, a photosensitive member A photoreceptor cleaner CLk as an example of an image carrier cleaner that removes the developer remaining on the surface of the body Pk is disposed. Further, the developing device Gk includes a developing container V in which a developer is accommodated, and a developing roll G1k as an example of a developer holder that holds and rotates the developer accommodated in the developing container 1. In the developing container V, a layer thickness regulating member Sk that is disposed to face the developing roll G1k and regulates the layer thickness of the developer on the surface of the developing roll G1k is provided. The developer container V includes stirring transport chambers V1 and V2 in which the developer supplied to the developing roll G1k is transported while stirring, and the developer is circulated in the stirring transport chambers V1 and V2. Circulating conveying members R1 and R2 for conveying are arranged. A developer replenishment path H1 for replenishing developer is connected to the left agitating and conveying chamber V2, and the developer replenishment path H1 is a first developer replenishment chamber H2 in which a replenishment developer is accommodated. Is connected. The first developer supply chamber H2 is connected to a second developer supply chamber H4 disposed above via a developer supply connection path H3. The developer is conveyed toward the agitating and conveying chambers V1 and V2 to the developer supply path H1, the first developer supply chamber H2, the developer supply connection path H3, and the second developer supply chamber H4, respectively. Replenishment developer conveying members R3, R4, R5, R6, and R7 are arranged. The developer replenishing containers H1 to H4 + R3 to R7 according to the first embodiment are configured by the members denoted by the reference numerals H1 to H4 and R3 to R7.

The surface of the photoreceptor Pk is uniformly charged by the charging roll CRk in the charging area Q1k facing the charging roll CRk, and then a latent image is written by the laser beam Lk in the latent image forming area Q2k. The written electrostatic latent image is visualized in the developing area Qgk facing the developing device Gk.
The black visible image forming device UK of Example 1 includes a photosensitive member Pk, a charger CRk, a developing device Gk, a static eliminating member Jk, a photosensitive member cleaner CLk, developer supply containers 11, 16 to 18, and the like that are integrally attached and detached. The image forming apparatus main body U1 is configured to be detachable from the image forming apparatus main body U1 in a state where the opening / closing part U2 is moved to the open position.
Other color visible image forming apparatuses UY, UM, UC are also detachable from the image forming apparatus main body U1, similarly to the black visible image forming apparatus UK, so-called process cartridges UY, UM, It is comprised by UC. In the printer U of the first embodiment, the process cartridges UY to UK are arranged side by side in the vertical direction.

  In FIG. 1, a belt module BM as an example of a belt-like member driving device is disposed on the right side of the photoreceptors Py to Pk. The belt module BM has an endless medium conveyance belt B as an example of a medium conveyance member disposed to face the process cartridges UY to UK. The medium conveying belt B is rotatably supported by a belt drive roll Rd as an example of a drive member and a belt support roll Rd + Rj as an example of a belt-like member support member including a driven roll Rj as an example of a driven member. . Further, the belt module BM has transfer rolls T1y, T1m, T1c, T1k as an example of a transfer unit disposed so as to be opposed to the respective photoreceptors Py to Pk as an example of a counter member with the medium transport belt B interposed therebetween. Have

On the downstream side of the medium conveying belt B in the medium conveying direction, that is, on the upper side, a density detection image formed by image density adjusting means (not shown) of the control unit C, that is, a so-called patch image density is detected at a predetermined time. An image density sensor SN1 is disposed as an example of the image density detection member. Note that, based on the image density detected by the image density sensor SN1, the image density adjusting means of the control unit C adjusts the voltage applied to the charging rolls CRy to CRk, the developing devices Gy to Gk, and the transfer rolls T1y to T1k. By adjusting the intensity of the latent image writing lights Ly to Lk, adjustment and correction of image density, so-called process control is performed.
A belt cleaner CLb as an example of a conveying member cleaner is disposed on the downstream side in the medium conveying direction of the medium conveying belt B of the image density sensor SN1. A medium adsorbing roll Rk as an example of a recording medium adsorbing member that adsorbs the recording sheet S to the medium conveying belt B is disposed at a position facing the driven roll Rj with the medium conveying belt B interposed therebetween.

The recording sheets S in the paper supply container TR1 disposed below the medium conveying belt B are taken out by a pick-up roll Rp as an example of a medium taking-out member and separated one by one by a separating roll Rs as an example of a medium separating member. Then, the sheet is conveyed to a recording medium conveyance path SH constituted by a sheet guide SG as an example of a guide member.
The recording sheet S in the recording medium conveyance path SH is sent to a registration roll Rr that adjusts the sheet feeding timing to the medium conveyance belt B as an example of a feeding member. The registration roll Rr feeds the recording sheet S at a predetermined timing to a recording medium suction position Q6 that is a region where the driven roll Rj and the medium suction roll Rk face each other. The recording sheet S conveyed to the recording medium adsorption position Q6 is electrostatically adsorbed to the medium conveyance belt B. In the belt module BM of Example 1, a guide member for guiding the recording sheet S is omitted between the registration roll Rr and the medium transport belt B.

The recording sheet S adsorbed on the medium conveying belt B sequentially passes through the transfer areas Q3y, Q3m, Q3c, and Q3k that are in contact with the photoreceptors Py to Pk.
To the transfer rolls T1y, T1m, T1c, and T1k disposed on the back side of the medium conveying belt B in the transfer areas Q3y, Q3m, Q3c, and Q3k, toner is supplied at a predetermined timing from the power supply circuit E controlled by the control unit C. A transfer voltage having a polarity opposite to the charging polarity is applied.
In the case of a multicolor image, the toner images on the respective photoreceptors Py to Pk are transferred onto the recording sheet S on the medium conveying belt B by the transfer rolls T1y, T1m, T1c, and T1k. Further, in the case of a monochromatic image, so-called monochrome image, only a K (black) toner image is formed on the photoreceptor Pk, and only this K (black) toner image is transferred to the recording sheet S by the transfer device T1k. .
After the toner images are transferred, the photoreceptors Py to Pk are neutralized by the neutralization members Jy to Jk in the neutralization areas Qjy to Qjk, and then the toner remaining on the surface is collected by the photoreceptor cleaners CLy to CLk in the cleaning areas Q4y to Q4k. And then charged again by the charging rolls CRy to CRk.

The recording sheet S on which the toner image is transferred is formed by fixing a heating roll Fh as an example of a heating fixing member of the fixing device F and a pressure roll Fp as an example of a pressure fixing member. It is fixed at Q5. The recording sheet S on which the image is fixed is guided by a guide roller Rgk as an example of a discharge guide member, and discharged from a discharge roller Rh as an example of a medium discharge member to the medium discharge portion TRh.
The medium conveying belt B after the recording sheet S is separated is cleaned by the belt cleaner CLb.

(Belt module BM)
FIG. 3 is an enlarged view of a main part of the image forming apparatus according to the first exemplary embodiment, illustrating a state in which the belt module is held at the use position.
FIG. 4 is an enlarged view of a main part of the image forming apparatus according to the first exemplary embodiment, illustrating a state where the belt module is moved to the maintenance work position.
FIG. 5 is a perspective view of the belt module according to the first exemplary embodiment, and illustrates a positional relationship between the image carrier and the transfer roll of the belt module.
FIG. 6 is an explanatory diagram of the belt module according to the first exemplary embodiment, FIG. 6A is a perspective view of the belt module in a state where the front plate of the belt support frame and the medium transport belt are removed from the belt module, and FIG. FIG. 6C is an explanatory diagram of the pin pressing device.
FIG. 7 is a side view of the belt module of Example 1, and shows a state in which the transfer frame is held at the pressing position.
FIG. 8 is a side view of the belt module according to the first exemplary embodiment, showing a state where the transfer frame has moved to the separation position.
FIG. 9 is a perspective view of the belt module according to the first exemplary embodiment, illustrating a state where the medium transport belt is removed from the belt module.

  3 to 6 and 9, the belt module BM has a pair of front and rear outer frames Fb as an example of a belt-like member support frame. The outer frame body Fb includes a front belt support plate Fb1 as an example of a front outer frame member and a rear belt support plate Fb2 as an example of a rear outer frame member. 5 and 9, the front belt support plate Fb1 and the rear belt support plate Fb2 are connected by a tie bar Fb3 as an example of a connection frame. 5 and 6, a drive shaft Rda that rotates integrally with the drive roll Rd is rotatably supported by bearings Br and Br at the upper ends of the front belt support plate Fb1 and the rear belt support plate Fb2. Yes. A rotational force transmission gear 11 is supported at the rear end of the drive shaft Rda, and a rotational force from a medium transport member drive source (not shown) is transmitted.

5 and 6, elongated holes 12 and 12 extending in the left-right direction are formed in the lower part of the front belt support plate Fb1 and the rear belt support plate Fb2.
In the front belt support plate Fb1 and the rear belt support plate Fb2, a driven roll Rj is rotatably supported below the long hole 12. The driven roll Rj is supported in a state in which the bearing 13 supporting the driven shaft Rja is pushed downward by an elastic member (not shown) so as to stretch the medium conveying belt B. It also has a function as a tension member that stretches.

3 to 5 and 9, concave grooves 14 and 14 are formed in the lower end portions of the front belt support plate Fb1 and the rear belt support plate Fb2. 3 and 4, the concave grooves 14 and 14 are rotatably supported by a frame support shaft 17 supported by the image forming apparatus main body U1. The belt module BM can rotate around the frame support shaft 17 between a normal use position shown in FIG. 3 and a maintenance work position shown in FIG.
In FIG. 3, in a state where the belt module BM is moved to the normal use position, the bearings Br and Br that support both ends of the drive shaft Rda come into contact with the positioning unit 18 provided in the image forming apparatus main body U1 and The belt module BM is positioned.
In FIG. 4, when performing maintenance work such as clearing a paper jam or replacing the visible image forming apparatuses UY to UK, the opening / closing unit U2 is opened, and the belt module BM is moved to the maintenance work position. It is opened and maintenance work is possible.

5 and 6, a transfer frame Ft as an example of a transfer member support frame is disposed inside the outer frame Fb. The transfer frame Ft has a pair of front and rear front transfer member supports and a front transfer roll support plate Ft1 and a rear transfer roll support plate Ft2 as an example of a rear transfer member support. The front and rear end portions of the drive shaft Rda pass through the upper end portions of the front transfer roll support plate Ft1 and the rear transfer roll support plate Ft2 in a rotatable state. That is, the upper end portion (Z direction end portion) of the transfer frame Ft is rotatably supported by the shaft Rda of the drive roll Rd.
Lower portions of the front transfer roll support plate Ft1 and the rear transfer roll support plate Ft2 are connected by a plate connecting member Ft3 as an example of a transfer member support connecting member. Both ends of the plate connecting member Ft3 pass through the long holes 13 and 13 of the front belt support plate Fb1 and the rear belt support plate Fb2, and protrude outward from the outer frame body Fb. Therefore, the plate connecting member Ft3 is supported in a freely movable state along the long holes 13 and 13.

  The front-side transfer roll support plate Ft1 and the rear-side transfer roll support plate Ft2 are formed with axial position adjusting elongated holes Fty, Ftm, Ftc, and Ftk corresponding to the positions of the transfer rolls T1y to T1k, respectively. Has been. In FIG. 6, the front-side transfer roll support plate Ft1 and the rear-side transfer roll support plate Ft2 are provided between a magenta axis position adjusting slot Ftc and a cyan axis position adjusting slot Ftc. A holding member support 19 that protrudes from the image carrier Py to Pk, that is, from the inside to the outside of the medium transport belt B, is formed. In FIG. 6B, the pressing member support portion 19 is formed with a pressing member position adjusting long hole 19a extending in the left-right direction. A belt pressing pin 20 as an example of a pressing member passes through the pressing member position adjusting long hole 19a and is supported so as to be movable along the pressing member position adjusting long hole 19a.

6A, an outer end portion of the belt pressing pin 20 is supported by a pin pressing device 21 as an example of a pressing member urging mechanism supported by the front transfer roll support plate Ft1 and the rear transfer roll support plate Ft2. Has been. In FIG. 6C, the pin pressing device 21 has a bearing member 21 a that rotatably supports the outer end portion of the belt pressing pin 20. The bearing member 21a is constantly pressed toward the medium conveying belt B by one end of an elastic spring 21b as an example of a pressing force generating member. The other end of the elastic spring 21b is supported by a spring support container 21c.
Further, as shown in FIG. 5, the pair of front and rear belt pressing pins 20 of the first embodiment are disposed outside the cleaning region L1 where the surface of the image carrier belt B is cleaned by the belt cleaner CLb. In Example 1, the cleaning area L1 is set wider than the maximum width of the usable recording sheet S, and the maximum width of the image forming area, which is an area of an image formed on the photoreceptors Py to Pk. Is set narrower than the maximum width of the recording sheet S.

5 and 6A, the shafts 22y, 22m, 22c, and 22k of the transfer rolls T1y, T1m, T1c, and T1k are movable to the left and right by a predetermined distance along the shaft position adjusting long holes Fty, Ftm, Ftc, and Ftk. It is supported. The shafts 22y to 22k of the transfer rolls T1y to T1k are supported by a shaft urging mechanism (not shown) configured similarly to the pin pressing device 21. That is, in FIGS. 7 and 8, each of the transfer rolls T1y to T1k is schematically shown by a transfer shaft biasing spring 23y, 23m, 23c, 23k corresponding to the elastic spring 21b. B is urged so as to push B toward the outer surface, that is, the photoreceptors Py to Pk.
In the first embodiment, the force pushed by the transfer shaft urging springs 23y to 23k is set to be larger than the force pushed by the elastic spring 21b. Further, the force with which the elastic spring 21b pushes the medium conveying belt B is slightly larger than the tension of the medium conveying belt B, so that the belt pressing pin 20 contacts the medium conveying belt B and hardly deforms the shape of the medium conveying belt B. Is set.

7 and 8, a support member urging member that applies a force that constantly pushes the plate connecting member Ft3 toward the photoreceptors Py to Pk between the plate connecting member Ft3 and the lower end portion of the outer frame body Fb. As an example, a transfer frame pressing spring SP is arranged. An eccentric cam HC as an example of a strip-shaped member contacting / separating member supported by the image forming apparatus main body U1 is disposed on the plate connecting member Ft3 so as to face the transfer frame pressing spring SP.
Therefore, when the eccentric cam HC moves to the belt-shaped member contact position shown in FIG. 7, the transfer frame push spring SP pushes the transfer frame Ft toward the photoconductors Py to Pk, and the medium transport belt B is all of the photoconductors Py. Contact ~ Pk. Therefore, a multicolor image is formed and transferred in this state. When the eccentric cam HC moves to the strip member separation position shown in FIG. 8, the transfer frame Ft rotates against the elastic force of the transfer frame pressing spring SP, and the medium conveying belt B is a photosensitive member Py, other than black. Separated from Pm and Pc. Therefore, a monochromatic image is formed and transferred in this state. That is, in Example 1, the black photosensitive member Pk is always in contact with the medium conveyance belt B, and the other color photosensitive members Py, Pm, and Pc are in contact with and separated from the medium conveyance belt B.

In FIG. 9, on the right side of the outer frame body Fb, there is a collection device KS that incorporates a belt cleaner CLb that removes paper dust, developer, and the like attached to the medium conveyance belt B when the recording sheet S is conveyed. It is supported. The collection device KS is formed with a grip portion KSa that is gripped by a user when the belt module BM is rotated from the normal use position shown in FIG. 3 to the maintenance work position shown in FIG.
The outer frame body Fb, the transfer frame Ft, the transfer frame pressing spring SP, the eccentric cam HC, and the like constitute a belt moving mechanism Fb + Ft + SP + HC as an example of the belt-like member moving mechanism of the first embodiment. The outer frame body Fb, the belt support roll Rd + Rj, the medium transport belt B, the transfer frame Ft, the transfer rolls T1y to T1k, the recovery device KS, and the like constitute a belt module BM of the first embodiment.

(Operation of Example 1)
FIG. 10 is a diagram showing the movement of the transfer frame and the arrangement state of the transfer rolls with the belt module moved to the normal use position, and FIG. 10A is the arrangement of the transfer rolls when the transfer frame is moved to the belt-like member contact position. FIG. 10B is a diagram showing the state of arrangement of the transfer rolls when the transfer frame is moved to the strip member separation position.
In the printer U as an example of the image forming apparatus according to the first embodiment having the above-described configuration requirements, when a multicolor image is printed, as shown in FIG. 10A, the medium is formed by the eccentric cam HC and the transfer frame pressing spring SP. The conveyance belt B moves to the multicolor image forming position, and all the photoconductors Py to Pk come into contact with the medium conveyance belt B. Accordingly, the respective photoreceptors Py to Pk are sequentially transferred to the recording sheet S that is attracted and conveyed by the medium conveying belt B, and is fixed by the fixing device S, so that a multicolor image is formed on the recording sheet S. At this time, in Example 1, the belt pressing pin 20 comes into contact with the medium conveying belt B, and the belt pressing pin 20 suppresses the fluttering of the medium conveying belt B.

  On the other hand, when a monochrome image is printed, as shown in FIG. 10B, the medium belt B is moved to the monochrome image forming position by the eccentric cam HC and the transfer frame pressing spring SP, and the black photosensitive member Pk has a transfer shaft. Only the black photosensitive member Pk comes into contact with the medium conveying belt B by the force spring 23k, and the other photosensitive members Py to Pk and the medium conveying belt B are separated. Therefore, the black image on the photoreceptor Pk is transferred to the recording sheet S that is attracted and conveyed by the medium conveying belt B, and a single-color image is formed on the recording sheet S. At this time, the driving of the visible image forming apparatuses UY, UM, UC other than black is stopped, so that the visible image forming apparatuses UY, UM, UC are deteriorated with time, for example, the photoconductors Py, Pm. Pc wear and the like are suppressed. At this time, in Example 1, the belt pressing pin 20 is brought into contact with the medium conveying belt B by the elastic spring 21b at both the multicolor image forming position and the monochromatic image forming position, and fluttering of the medium conveying belt B is suppressed.

That is, when the recording sheet S enters the medium conveyance belt B or when the recording sheet S enters the transfer area Q3k, the fluctuation of the medium conveyance belt B is reduced, and stable conveyance is possible. This reduces the contact of the recording sheet S with the non-black photoconductors Py to Pc when flapping occurs, and prevents the recording sheet S from being soiled. In particular, in the first exemplary embodiment, the belt pressing pin 20 is disposed in the vicinity of the cyan photosensitive member Pc having the smallest separation distance and on the upstream side in the medium conveyance direction, and the fluttering in the vicinity of the cyan photosensitive member Pc occurs. Thus, the contact between the cyan photosensitive member Pc and the recording sheet S is reduced.
In the first embodiment, the pressing force of the elastic spring 21b is set to be smaller than the elastic force of the transfer shaft biasing springs 23y to 23c, and the shape of the medium conveying belt B hardly changes, and the recording sheet S is conveyed. Performance is ensured. Further, since the shape of the medium conveyance belt B is maintained, the difference in the angle of the recording sheet S entering the transfer area Q3k is reduced during the formation of the single color image and the multicolor image, and the shape of the medium conveyance belt is reduced. Setting transfer conditions, that is, discharge conditions, is easier than in the case of being deformed and separated from the photoreceptor. That is, as the angle of entering the transfer region Q3k from the transfer roll T1k side is larger, abnormal discharge, so-called gap discharge, is more likely to occur between the photoreceptor Pk and the recording sheet S, and image defects associated with abnormal discharge occur. Although it becomes easy, in Example 1, generation | occurrence | production of abnormal discharge and an image defect is reduced compared with these cases.

  In the printer U according to the first exemplary embodiment, the positional relationship between the registration roll Rr and the upstream end of the medium conveyance belt B is a single color image or a multicolor image due to a change in the shape of the medium conveyance belt B due to the movement of the transfer frame Ft. And does not change. For this reason, the recording sheet S fed out from the registration roll Rr is stably sent out to the medium transport belt B, and is sucked and transported. That is, in the image forming apparatus in which the medium is conveyed in the vertical direction, when the positional relationship between the registration roll Rr and the medium conveyance belt B changes, when the recording sheet S is sent to the medium conveyance belt B, the gravity of As a result, the position of the recording medium may not be stabilized. However, in the first embodiment, since the positional relationship between the registration roll Rr and the medium conveying belt B does not change, it can be stably adsorbed and conveyed. . That is, the recording sheet S is stably conveyed because the medium is unlikely to come into contact with the photoreceptors Py to Pc that are separated due to poor adsorption during monochrome printing.

In the printer U according to the first exemplary embodiment, the positional relationship between the registration roll Rr and the medium conveyance belt B does not change. Therefore, a special timing such as changing the timing of feeding from the registration roll Rr between the single-color image formation position and the multicolor image formation position. There is no need to control, and the recording sheet S is fed out at a stable time. In other words, since the position of the recording sheet S attracted to the medium conveying belt B is stabilized, it is possible to prevent the position of the image from being varied due to the positional deviation of the recording sheet S and to obtain a good image quality.
Furthermore, in the printer U according to the first embodiment, the belt pressing pin 20 is disposed outside the cleaning region L1, and the region where the belt pressing pin 20 of the medium transport belt B contacts is cleaned by the belt pressing pin 20. In particular, in the first embodiment, the belt pressing pin 20 rotates following the rotation of the medium conveying belt B, and wear of the belt pressing pin 20 and the medium conveying belt B is reduced as compared with the case where the belt pressing pin 20 does not rotate.

(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. Modification examples (H01) to (H010) of the present invention are exemplified below.
(H01) In the above-described embodiment, the printer as the image forming apparatus has been exemplified. However, the present invention is not limited to this, and a FAX, a copying machine, or a multifunction machine having all or a plurality of functions may be used. Further, the present invention is not limited to an electrophotographic image forming apparatus, and the configuration described in the embodiments can also be applied to a medium transport member in a so-called inkjet recording image forming apparatus.

(H02) In the above embodiment, the movement of the medium conveying belt B is controlled by the action of the eccentric cam HC and the transfer frame pressing spring SP. However, the present invention is not limited to this, and an arbitrary configuration capable of moving the medium conveying belt B is adopted. Is possible. For example, a so-called solenoid can be used instead of the eccentric cam HC, or the weight of the transfer frame Ft can be used by adjusting the position of the center of gravity of the transfer frame Ft instead of the transfer frame pressing spring SP.
(H03) In the above-described embodiment, the case of an image forming apparatus having four colors Y, M, C, and K is exemplified. However, the present invention is not limited to four colors, and is applicable to image forming apparatuses having three colors or less or five colors or more. Is possible.

(H04) In the above embodiment, a configuration in which the belt pressing pin 20 is pressed against the medium transport belt B by the pin pressing device 21 is illustrated. Although the configuration is desirable, the configuration is not limited to this configuration, and any configuration can be adopted. For example, if the medium conveying belt B is set and designed so as to ensure contact with the medium conveying belt B in a state where the medium conveying belt B is separated from the photoconductors Py to Pc, the pin pressing device 21 is omitted and the belt is omitted. The pressing pin 20 can be rotatably supported by the pressing member support portion 19 or can be fixedly supported. It is also possible to form the belt pressing pin 20 integrally with the pressing member support portion 19.
(H05) In the above-described embodiment, the belt pressing pin 20 is disposed on the upstream side of the cyan photoconductor Pc in the medium conveyance direction, and this position is desirable. However, the position is not limited to this, and the position to be disposed is designed or specified. It can be arbitrarily changed according to the above.

(H06) In the above embodiment, the medium conveying belt is exemplified as an example of the belt-shaped member. However, the present invention is not limited to this. For example, an endless belt such as an intermediate transfer belt in which a belt cleaner or a secondary transfer member contacts and separates is used. It can be applied to a band-shaped member.
(H07) In the above-described embodiment, the configuration in which the black photosensitive member Pk is arranged at the upper end is illustrated, but the configuration is not limited to this configuration, and the arrangement position can be arbitrarily changed according to the configuration, the design, and the like.
(H08) In the above-described embodiment, the configuration in which the medium conveying belt is cleaned by the belt pressing pin 20 is illustrated. However, the configuration is not limited to this configuration, and a configuration in which cleaning is not performed is also possible. Moreover, in order to perform cleaning efficiently, a porous body such as a so-called sponge can be provided on the outer peripheral surface of the belt pressing pin 20, or brush-like hair can be implanted.

(H09) In the above-described embodiment, the belt pressing pin 20 is exemplified as the pressing member. However, the shape is not limited to the pin shape, and the pressing member is pressed in contact with a belt such as a cylindrical body, a prismatic body, or a brush-like body. It is possible to make it an arbitrary shape.
(H010) In the above-described embodiment, the belt pressing pin 20 and the pin pressing device 21 are provided in the belt module BM as an example of the belt-shaped member driving device, and are configured to be movable along with the movement of the medium conveying belt B. For example, the belt pressing pin and the pin pressing device 21 are arranged on the image forming apparatus main body U1 side by adjusting the moving range of the belt pressing pin and the elastic force of the elastic spring 21b, or the outer frame body Fb. It is also possible to arrange them.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is an explanatory diagram of a visible image forming apparatus which is an example of a detachable body according to the first embodiment of the present invention. FIG. 3 is an enlarged view of a main part of the image forming apparatus according to the first exemplary embodiment, illustrating a state in which the belt module is held at the use position. FIG. 4 is an enlarged view of a main part of the image forming apparatus according to the first exemplary embodiment, illustrating a state where the belt module is moved to the maintenance work position. FIG. 5 is a perspective view of the belt module according to the first exemplary embodiment, and illustrates a positional relationship between the image carrier and the transfer roll of the belt module. FIG. 6 is an explanatory diagram of the belt module according to the first exemplary embodiment, FIG. 6A is a perspective view of the belt module in a state where the front plate of the belt support frame and the medium transport belt are removed from the belt module, and FIG. FIG. 6C is an explanatory diagram of the pin pressing device. FIG. 7 is a side view of the belt module of Example 1, and shows a state in which the transfer frame is held at the pressing position. FIG. 8 is a side view of the belt module according to the first exemplary embodiment, showing a state where the transfer frame has moved to the separation position. FIG. 9 is a perspective view of the belt module according to the first exemplary embodiment, illustrating a state where the medium transport belt is removed from the belt module. FIG. 10 is a diagram showing the movement of the transfer frame and the arrangement state of the transfer rolls with the belt module moved to the normal use position, and FIG. 10A is the arrangement of the transfer rolls when the transfer frame is moved to the belt-like member contact position. FIG. 10B is a diagram showing the state of arrangement of the transfer rolls when the transfer frame is moved to the strip member separation position.

Explanation of symbols

20: holding member,
B ... Band-shaped member, medium conveying member,
BM ... belt-shaped member driving device,
CLb ... Conveying member cleaner
Fb + Ft + SP + HC ... strip member moving mechanism,
L1 ... cleaning area,
Py, Pm, Pc, Pk ... opposing member, image carrier,
Rd + Rj, T1y, T1m, T1c, T1k ... support member,
S ... medium,
T1y, T1m, T1c, T1k ... transfer member,
U: Image forming apparatus.

Claims (8)

An endless belt-like member whose inner surface is rotatably supported by a plurality of support members;
A belt-shaped member moving mechanism that moves the belt-shaped member close to and away from a facing member disposed to face the outer surface of the belt-shaped member;
A pressing member that presses the band-shaped member in contact with the outer surface of the band-shaped member in a state where the band-shaped member is separated from the facing member;
An urging member that urges the pressing member against the belt-shaped member;
With
The opposing member has an opposing member that approaches and separates from the belt-like member by movement of the belt-like member, and an opposing member that continues to contact before and after the movement of the belt-like member,
The band-shaped member moving mechanism is centered on a rotation center disposed on the opposite side with respect to the counter member that is close to and separated from the band-shaped member across the counter member that continues to contact before and after the movement of the band-shaped member. Moving the strip member relative to the opposing member;
The pressing member is disposed on the upstream side in the moving direction of the band-shaped member with respect to the opposing member that continues to contact before and after the movement of the band-shaped member, and outside the cleaning region of the cleaner that cleans the band-shaped member , The belt member is driven to rotate while being urged by the urging member and in contact with the belt-like member, and the belt-like member is contacted with the belt-like member and cleaned before and after the opposing member contacts and separates from the belt-like member. A belt-like member driving device characterized by the above. The support member disposed in a state in which the band-shaped member is pushed from the inner surface side toward the outer surface side;
The pressing member that presses the outer surface of the band-shaped member to the inner surface side with a force that is weaker than the force that pushes the band-shaped member to the outer surface side by the support member;
The belt-shaped member driving device according to claim 1, comprising: The pressing member that moves integrally in response to the operation of approaching and separating from the facing member,
The belt-shaped member driving device according to claim 1, wherein the belt-shaped member driving device is provided. The opposing member composed of an image carrier that holds and rotates an image on the surface;
The endless belt-shaped member configured by a medium conveying member that rotates while holding the medium on the surface;
The support member configured by a transfer member that transfers an image of the surface of the image carrier to the medium;
The pressing member disposed on the outer side in the medium width direction of the medium held on the surface of the image holding body with respect to the medium width direction intersecting the medium moving direction;
An image forming apparatus comprising the belt-shaped member driving device according to claim 1. A transport member cleaner for cleaning the surface of the medium transport member in a cleaning region including the width of the image;
The pressing member disposed outside the cleaning region in the medium width direction; and
The image forming apparatus according to claim 4, further comprising: A plurality of the image holding bodies having an image holding body that approaches and separates from the belt-like member by movement of the belt-like member by the belt-like member moving mechanism, and an image holding body that continues to contact before and after the movement of the belt-like member;
The pressing member disposed in the vicinity of the image carrier that is close to and away from the belt-shaped member;
The image forming apparatus according to claim 4, further comprising: The image carrier that continues to contact before and after the movement of the belt-shaped member disposed on the downstream side of the image carrier that is close to and away from the belt-shaped member with respect to the medium transport direction of the medium transport member;
The pressing member disposed on the downstream side in the medium conveying direction of the image holding member that is close to and separated from the belt-shaped member;
The image forming apparatus according to claim 6, further comprising: A plurality of the image holding bodies having an image holding body that approaches and separates from the belt-like member by the movement of the belt-like member by the belt-like member moving mechanism and the image holding body that continues to contact before and after the movement of the belt-like member are vertically moved. Arranged side by side,
The medium conveying direction of the medium conveying member is set in a direction from the lower side to the upper side, and the image holding body that continues to contact before and after the movement of the belt-like member is disposed at the uppermost position that is the most downstream in the medium conveying direction. The image forming apparatus according to claim 4, wherein the image forming apparatus is an image forming apparatus.

Images