JP2016148790A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress idling of an endless belt-like rotating body, while applying voltage to a driving member of the endless belt-like rotating body.SOLUTION: An image forming apparatus (U) comprises: an endless belt-like rotating body (B); a driving member (T2a) that supports and drives the endless belt-like rotating body (B) to rotate the endless belt-like rotating body (B), the driving member (T2a) to which a predetermined voltage is applied; and a cleaning member (11) that cleans the driving member (T2a).SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus.

  Regarding conventional electrophotographic copying machines, image forming apparatuses such as printers, etc., regarding a cleaning device that removes adhering matter such as floating toner, paper powder, and discharge products adhering to a rotating member such as a transfer member and a charging member, The technologies described in Patent Documents 1 and 2 are known.

Japanese Patent Application Laid-Open No. 2008-70532 as Patent Document 1 describes a configuration of a cleaning roller (12) that contacts and cleans a charging roller (10) that charges the photosensitive drum (1). In the configuration of Patent Document 1, a charging voltage is applied to the charging roller (10) to be cleaned by the cleaning roller (12), and the charging roller (10) rotates in contact with the photosensitive drum (1). .
Further, Patent Document 1 describes the configuration of a cleaning roller (9) that contacts and cleans the photosensitive drum (1). The photosensitive drum (1) that is cleaned by the cleaning roller (9) includes: No voltage is applied, and the photosensitive drum (1) is driven.

  Japanese Patent Application Laid-Open No. 2011-145416 as Patent Document 2 describes a configuration of a roller-shaped cleaning member (100) for cleaning the charging member (14). Similar to the configuration of Patent Document 1, a charging voltage is applied to the charging member (14) to be cleaned by the cleaning member (100), and the charging member (14) contacts the photoreceptor (12) and is driven to rotate. To do.

JP 2008-70532 A (“0016” to “0019”, FIGS. 1 to 3) JP 2011-145416 A ("0015" to "0023", "0045", "0046", FIG. 1 to FIG. 6, FIG. 8)

  An object of the present invention is to suppress idling of an endless belt-like rotating body while applying a voltage to a drive member of the endless belt-like rotating body.

In order to solve the technical problem, an image forming apparatus according to claim 1 is provided.
An endless belt-like rotating body,
A driving member that supports and drives the endless belt-like rotating body to rotate the endless belt-like rotating body, and the driving member to which a preset voltage is applied;
A cleaning member for cleaning the drive member;
It is provided with.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect,
The cleaning member which can be driven and rotated in contact with the driving member;
It is provided with.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect,
A deposit disposed on the downstream side of the drive member with respect to the rotation direction of the endless belt-like rotating body and applied with a preset voltage, and detached from the cleaning member and attached to the endless belt-like rotating body. A recovery member for recovering,
It is provided with.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects,
The endless belt-like rotating body constituted by an endless belt-like image holding body that rotates while holding a visible image on the surface;
The drive member constituted by a transfer member to which a transfer voltage for transferring a visible image held on the surface of the endless belt-like image carrier to a medium is applied;
It is provided with.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects,
An image carrier that holds and rotates a visible image on the surface;
The drive member constituted by a transfer member to which a transfer voltage for transferring a visible image held on the surface of the image carrier to a medium is applied;
The endless belt-like rotating body that is sandwiched between the image holding member and the transfer member and is configured by an endless belt-like transport member that transports the medium while holding the medium;
It is provided with.

According to the first aspect of the present invention, as compared with a configuration that does not have a cleaning member that cleans the drive member of the endless belt-like rotating body, the idling of the endless belt-like rotating body is suppressed while applying a voltage to the drive member. can do.
According to the second aspect of the present invention, the difference in surface speed generated between the drive member and the cleaning member is reduced as compared with the configuration without the cleaning member that rotates following the drive member. It is possible to reduce the rubbing of the developer against the toner.
According to the third aspect of the present invention, compared with the configuration without the recovery member, the deposit attached to the endless belt-like rotator can be recovered by the recovery member and separated from the cleaning member. Can be reduced.

According to the fourth aspect of the present invention, it is possible to suppress the idle rotation of the endless belt-shaped image carrier, and it is possible to suppress the deterioration of the image quality due to the rotation failure of the image carrier.
According to the fifth aspect of the present invention, it is possible to suppress idle rotation of the endless belt-shaped transport member, and it is possible to suppress deterioration in image quality due to poor transport of the medium.

FIG. 1 is an overall explanatory view of an image forming apparatus according to a first embodiment. FIG. 2 is an explanatory diagram of a main part of the image forming apparatus according to the first embodiment. FIG. 3 is an enlarged explanatory view of a main part of the intermediate transfer device according to the first embodiment. FIG. 4 is an explanatory diagram of a state in which an endless belt-like rotating body is attached to the intermediate transfer device of the first embodiment. FIG. 5 is an explanatory view of the offset regulating mechanism of the endless belt-like rotating body of the first embodiment. FIG. 6 is an enlarged explanatory view of the cleaning member of the first embodiment. FIG. 7 is an explanatory diagram of a method for measuring the friction coefficient of the backup roll surface in Experimental Example 1. FIG. 8 is a list showing the experimental results of Experimental Example 1, in which the horizontal axis indicates the number of running media and the vertical axis indicates the surface friction coefficient of the driving members of the experimental example and the comparative example.

Next, specific examples of embodiments of the present invention (hereinafter referred to as examples) 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 a first embodiment.
FIG. 2 is an explanatory diagram of a main part of the image forming apparatus according to the first embodiment.
In FIG. 1, a copier U as an example of an image forming apparatus according to a first exemplary embodiment of the present invention is an example of a recording unit, and includes a printer unit U1 as an example of an image recording apparatus. A scanner unit U2 as an example of a reading unit and an example of an image reading device is supported on the upper portion of the printer unit U1. An auto feeder U3 as an example of a document transport device is supported on the upper portion of the scanner unit U2. The scanner unit U2 of the first embodiment supports a user interface UI as an example of an input unit. The user interface UI can be operated by the operator by inputting the user interface UI.

  A document tray TG1 as an example of a medium container is disposed on the upper part of the auto feeder U3. A plurality of documents Gi to be copied can be stacked and stored in the document tray TG1. A document discharge tray TG2 as an example of a document discharge unit is formed below the document tray TG1. A document transport roll U3b is disposed between the document tray TG1 and the document discharge tray TG2 along the document transport path U3a.

A platen glass PG as an example of a transparent document table is disposed on the upper surface of the scanner unit U2. In the scanner unit U2 of the first embodiment, a reading optical system A is disposed below the platen glass PG. The optical system A for reading in Example 1 is supported so as to be movable in the left-right direction along the lower surface of the platen glass PG. The reading optical system A is normally stopped at the initial position shown in FIG.
An imaging member CCD as an example of a reading member is disposed on the left side of the reading optical system A. An image processing unit IPS is electrically connected to the imaging member CCD.

The image processing unit IPS is electrically connected to the writing circuit DL of the printer unit U1. The writing circuit DL is an example of a latent image forming apparatus, and is electrically connected to LED heads LHy, LHm, LHc, and LHk as an example of an exposure apparatus.
The LED heads LHy, LHm, LHc, and LHk of Example 1 are arranged corresponding to each color of Y, M, C, and K. Note that the LED heads LHy to LHk of Example 1 are configured by an LED array in which LEDs as an example of light emitting elements are linearly arranged along the width direction of an image. The LED heads LHy to LHk are configured so that the LEDs can emit light in accordance with an input signal. That is, the LED heads LHy to LHk are configured to be able to output writing light according to the input signal.

In FIG. 1, photoconductors PRy, PRm, PRc, and PRk, which are examples of image carriers, are disposed above the LED heads LHy to LHk. The write areas Q1y, Q1m, Q1c, and Q1k are configured by areas where the photoconductors PRy to PRk and the LED heads LHy to LHk face each other.
Charging rolls CRy, CRm, CRc, and CRk as an example of a charger are disposed upstream of the LED heads LHy to LHk with respect to the rotation direction of each of the photoconductors PRy, PRm, PRc, and PRk. The charging rolls CRy to CRk of Example 1 are supported so as to be driven to rotate in contact with the photoreceptors PRy to PRk.
Developing devices Gy, Gm, Gc, and Gk are disposed on the downstream side of the LED heads LHy to LHk with respect to the rotation direction of the photoconductors PRy to PRk. Development regions Q2y, Q2m, Q2c, and Q2k are configured by regions where the photoconductors PRy to PRk and the developing devices Gy to Gk face each other.

Primary transfer rolls T1y, T1m, T1c, and T1k as an example of a primary transfer unit are disposed on the downstream side of the developing devices Gy to Gk with respect to the rotation direction of the photosensitive members PRy to PRk. The primary transfer regions Q3y, Q3m, Q3c, and Q3k are configured by regions where the photoconductors PRy to PRk and the primary transfer rolls T1y to T1k face each other.
Photoreceptor cleaners CLy, CLm, CLc, and CLk as an example of an image carrier cleaner are disposed downstream of the primary transfer rolls T1y to T1k with respect to the rotation direction of the photoreceptors PRy to PRk. .

  The Y color of Example 1 in which a toner image as an example of a visible image is formed by the Y color photoreceptor PRy, the charging roll CRy, the LED head LHy, the developing device Gy, the primary transfer roll T1y, and the photoreceptor cleaner CLy. A Y-color image forming unit Uy as an example of the visible image forming apparatus is configured. Similarly, each photoconductor PRm, PRc, PRk, charging roll CRm, CRc, CRk, LED head LHm, LHc, LHk, developing device Gm, Gc, Gk, primary transfer roll T1m, T1c, T1k, photoconductor cleaner CLm. , CLc, CLk constitute the image forming portions Um, Uc, Uk of the M, C, K colors.

Above the photoconductors PRy to PRk, a belt module BM as an example of an intermediate transfer device is disposed. The belt module BM is an example of an image carrier, and includes an intermediate transfer belt B as an example of an intermediate transfer member. The intermediate transfer belt B is composed of an endless belt-like member.
The intermediate transfer belt B according to the first exemplary embodiment includes a tension roll Rt as an example of a stretching member, a walking roll Rw as an example of a member that corrects a deviation, an idler roll Rf as an example of a driven member, and a secondary roll. It is an example of an opposing member in the transfer region, and is rotatably supported by a backup roll T2a as an example of a drive member and primary transfer rolls T1y, T1m, T1c, and T1k.

A secondary transfer roll T2b as an example of a secondary transfer member is disposed at a position facing the backup roll T2a across the intermediate transfer belt B. In Embodiment 1, a secondary transfer voltage having the same polarity as the toner charging polarity is applied from the power supply circuit E to the backup roll T2a, and the secondary transfer roll T2b is grounded. The backup roll T2a and the secondary transfer roll T2b constitute the secondary transfer device T2 of the first embodiment. Further, the secondary transfer region Q4 is constituted by the region where the secondary transfer roll T2b and the intermediate transfer belt B are in contact with each other.
A belt cleaner CLb is disposed on the downstream side of the secondary transfer region Q4 with respect to the rotation direction of the intermediate transfer belt B as an example of an intermediate transfer member cleaner.
The primary transfer rolls T1y to T1k, the intermediate transfer belt B, the secondary transfer unit T2, and the like constitute a transfer device T1 + T2 + B of the first embodiment. The image recording units Uy to Uk + T1 + T2 + B of the first embodiment are configured by the image forming units Uy to Uk and the transfer device T1 + T2 + B.

In FIG. 1, three pairs of left and right guide rails GR as an example of a guide member are provided below the image forming units Uy to Uk. On each guide rail GR, paper feed trays TR1 to TR3, which are examples of medium accommodating portions, are supported so as to be able to enter and exit in the front-rear direction. Recording sheets S as an example of a medium are accommodated in the paper feed trays TR1 to TR3.
A pickup roll Rp as an example of a take-out member is disposed on the upper right side of the paper feed trays TR1 to TR3. A separating roll Rs as an example of a separating member is disposed downstream of the pickup roll Rp with respect to the conveyance direction of the recording sheet S. As an example of a medium transport path, a paper feed path SH1 extending upward is formed on the downstream side of the separation roll Rs with respect to the transport direction of the recording sheet S. A plurality of transport rolls Ra as an example of a transport member is disposed in the paper feed path SH1.

In the sheet feeding path SH1, a registration roll Rr as an example of a conveyance timing adjusting member is disposed on the upstream side of the secondary transfer region Q4.
A fixing device F is disposed on the downstream side of the secondary transfer region Q4 with respect to the conveyance direction of the sheet S. The fixing device F includes a heating roll Fh as an example of a fixing member for heating and a pressure roll Fp as an example of a fixing member for pressure. A fixing region Q5 is constituted by a contact region between the heating roll Fh and the pressure roll Fp.
Above the fixing device F, a paper discharge path SH2 as an example of a transport path is disposed. A paper discharge tray TRh as an example of a medium discharge unit is formed on the upper surface of the printer unit U1. The paper discharge path SH2 extends toward the paper discharge tray TRh. A paper discharge roll Rh, which is an example of a medium transport member, is disposed at the downstream end of the paper discharge path SH2.

(Description of image forming operation)
In the copying machine U according to the first embodiment having the above-described configuration, when the copying operation is started, the plurality of documents Gi stored in the document tray TG1 sequentially pass through the document reading positions on the platen glass PG, The document is discharged to a paper discharge tray TG2.
When the automatic feeder U3 is used to automatically convey and copy a document, each document that sequentially passes through the reading position on the platen glass PG with the reading optical system A stopped at the initial position. Gi is exposed. When the operator places the document Gi on the platen glass PG by hand, the optical system A for reading moves in the left-right direction, and the document on the platen glass PG is scanned while being exposed.
Reflected light from the original document Gi passes through the optical system A for reading and is condensed on the imaging member CCD. The imaging member CCD converts the reflected light of the document Gi focused on the imaging surface into an electrical signal.

The image processing unit IPS receives an electrical signal output from the imaging member CCD. The image processing unit IPS converts the electrical signals of the R, G, and B color images read by the imaging member CCD into image information of yellow Y, magenta M, cyan C, and black K for forming a latent image. The image processing unit IPS outputs the converted image information to the writing circuit DL of the printer unit U1. Note that the image processing unit IPS outputs image information of only black K to the writing circuit DL when the image is a monochrome image, so-called monochrome.
The writing circuit DL outputs a control signal corresponding to the input image information to the LED heads LHy to LHk. The LED heads LHy to LHk output writing light according to the control signal.

  Each of the photoconductors PRy to PRk is driven to rotate when image formation is started. A charging voltage is applied from the power supply circuit E to the charging rolls CRy to CRk. Therefore, the surfaces of the photoconductors PRy to PRk are charged by the charging rolls CRy to CRk. Electrostatic latent images are formed on the surfaces of the charged photoconductors PRy to PRk by writing light from the LED heads LHy to LHk in the writing areas Q1y to Q1k. The electrostatic latent images on the photoconductors PRy to PRk are developed into toner images as an example of visible images by the developing devices Gy, Gm, Gc, and Gk in the development areas Q2y to Q2k.

The developed toner image is conveyed to primary transfer regions Q3y, Q3m, Q3c, and Q3k that are in contact with the intermediate transfer belt B. In the primary transfer regions Q3y, Q3m, Q3c, and Q3k, a primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied from the power supply circuit E to the primary transfer rolls T1y to T1k. Accordingly, the toner images on the photoconductors PRy to PRk are transferred to the intermediate transfer belt B by the primary transfer rolls T1y to T1k. In the case of a multi-color toner image, the downstream toner image is transferred so as to overlap the toner image transferred to the intermediate transfer belt B in the upstream primary transfer region.
Residues and deposits on the photoconductors PRy to PRk after the primary transfer are cleaned by the photoconductor cleaners CLy to CLk. The cleaned surfaces of the photoconductors PRy to PRk are recharged by the charging rolls CRy to CRk.
The single-color or multicolor toner images transferred onto the intermediate transfer belt B by the primary transfer rolls T1y to T1k in the primary transfer areas Q3y to Q3k are conveyed to the secondary transfer area Q4.

The sheet S on which an image is recorded is taken out by the pickup rolls Rp of the paper feed trays TR1 to TR3 to be used. The sheets S picked up by the pick-up roll Rp are separated one by one by the rolls Rs when a plurality of sheets S are picked up. The sheet S separated by the separating roll Rs is conveyed through the sheet feeding path SH1 by the conveying roll Ra. The sheet S conveyed through the sheet feeding path SH1 is sent to the registration roll Rr.
The registration roll Rr conveys the sheet S to the secondary transfer area Q4 at the same time when the toner image formed on the intermediate transfer belt B is conveyed to the secondary transfer area Q4. A secondary transfer voltage having the same polarity as the toner charging polarity is applied to the backup roll T2a by the power supply circuit E. Therefore, the toner image on the intermediate transfer belt B is transferred from the intermediate transfer belt B to the sheet S.

The intermediate transfer belt B after the secondary transfer is cleaned of deposits and the like adhering to the surface by the belt cleaner CLb.
The recording sheet S on which the toner image has been secondarily transferred is heated and fixed when passing through the fixing region Q5.
The recording sheet S on which the image is fixed is conveyed through the paper discharge path SH2. The sheet S conveyed through the paper discharge path SH2 is discharged to the paper discharge tray TRh by the paper discharge roll Rh.

(Description of intermediate transfer device)
FIG. 3 is an enlarged explanatory view of a main part of the intermediate transfer device according to the first embodiment.
FIG. 4 is an explanatory diagram of a state in which an endless belt-like rotating body is attached to the intermediate transfer device of the first embodiment.
1 to 4, a backup roll T2a as an example of a drive member has a rotation shaft 1 that extends in the front-rear direction, which is the width direction of an intermediate transfer belt B as an example of an endless belt-like rotator. A roll body 2 is supported on the rotary shaft 1. The roll body 2 according to the first exemplary embodiment is formed in a columnar shape extending in the front-rear direction according to the width direction of the intermediate transfer belt B.
Further, the backup roll T2a according to the first embodiment is driven by a motor M1 as an example of a drive source.

FIG. 5 is an explanatory view of the offset regulating mechanism of the endless belt-like rotating body of the first embodiment.
3 to 5, a rib guide 3 as an example of a offset regulating member is supported on the rotating shaft 1 on the outer side in the front-rear direction of the main body 2 of the roll. The rib guide 3 according to the first embodiment is supported so as to be freely rotatable with respect to the rotating shaft 1. Further, each rib guide 3 of the first embodiment is formed with a cylindrical large-diameter portion 3a extending outward from the inner end in the front-rear direction along the rotation axis 1. The outer diameter of the large diameter portion 3a is formed to be the same as the outer diameter of the main body 2 of the roll. At the outer end of the large-diameter portion 3a, a truncated cone-shaped tapered portion 3b whose diameter decreases as going outward is continuously formed.
A small-diameter portion 3c extending outward along the rotation shaft 1 is continuously formed at the outer end of the tapered portion 3b. The outer diameter of the small diameter portion 3c is smaller than the outer diameter of the large diameter portion 3a.

In FIG. 5, a rib 6 as an example of a one-sided restricting portion is supported on the inner surface of the intermediate transfer belt B at the outer end portion in the width direction. The rib 6 according to the first exemplary embodiment protrudes inward along the inner periphery of the intermediate transfer belt B. Moreover, the rib 6 of Example 1 is arrange | positioned corresponding to the small diameter part 3c.
FIG. 6 is an enlarged explanatory view of the cleaning member of the first embodiment.
A cleaning member 11 as an example of a cleaning member is disposed on the right side of the backup roll T2a. 2 to 4, the cleaning member 11 includes a cleaning shaft 12 as an example of a shaft of the cleaning member. On the outer peripheral surface of the cleaning shaft 12, a roll portion 13 as an example of a main body of the cleaning member is supported. The roll part 13 of Example 1 is formed in the column shape extended in the front-back direction.

As shown in FIG. 6, the roll portion 13 of the first embodiment is formed by spirally winding a belt-shaped cleaning material 14 that can be elastically deformed on the peripheral surface of the cleaning shaft 12. In addition, the foaming member made from a polyurethane is used for the cleaning material 14 of Example 1. FIG.
In the configuration of the first embodiment, the roll portion 13 is formed such that the position of the outer end in the axial direction of the roll portion 13 is inside the outer end in the axial direction of the main body 2 of the roll. Further, both ends of the cleaning member 11 in the axial direction are pressed against the backup roll T2a by springs as an example of a biasing member (not shown). Therefore, the cleaning member 11 is driven to rotate as the backup roll T2a rotates.

  With respect to the rotation direction of the intermediate transfer belt B, on the downstream side of the backup roll T2a, from the upstream side, a tension roll Rt, an idler roll Rf, primary transfer rolls T1y to T1k as examples of a recovery member, and a walking roll Rw Are arranged in the order of. In the configuration of the first embodiment, the intermediate transfer belt B is stretched around the backup roll T2a, the tension roll Rt, the idler roll Rf, the primary transfer rolls T1y to T1k, and the walking roll Rw.

(Operation of Example 1)
In the copying machine U of Example 1 having the above-described configuration, the negatively charged toner is transferred from the surface of the photoreceptors PRy to PRk to the surface of the intermediate transfer belt B with a positive primary transfer voltage. Then, the toner image on the intermediate transfer belt B is transferred to the recording sheet S passing through the secondary transfer region Q4 applied to the backup roll T2a with a negative secondary transfer voltage.
Here, in the copying machine U of the first embodiment, the toner deteriorates due to a load such as agitation in the developing devices Gy to Gk and a discharge in the developing regions Q2y to Q2k and the transfer regions Q3y to Q3k, Q4. . The deteriorated toner may change from a normal negative polarity to a positive polarity having a reverse polarity.

  The toner may float due to the movement of the developer in the development areas Q2y to Q2k, the movement or vibration of the intermediate transfer belt B, the recording sheet S, or the like in each of the transfer areas Q3y to Q3k, Q4. The floating charged toner may be attracted electrostatically to the primary transfer rolls T1y to T1k to which a voltage is applied or the backup roll T2a. When the toner adheres to the surface of the backup roll T2a, the frictional force of the backup roll T2a is reduced, and the intermediate transfer belt B may be easily slipped.

Here, if the intermediate transfer belt B slides with respect to the backup roll T2a that drives the intermediate transfer belt B, the behavior of the intermediate transfer belt B during rotation becomes unstable. Therefore, there is a problem that image quality deterioration such as misalignment or color misregistration of the image transferred on the intermediate transfer belt B, streak image defects accompanying so-called speed fluctuation of the intermediate transfer belt B, so-called banding, and the like occurs. .
In Patent Documents 1 and 2, a charging voltage is applied to the charging member, but the charging member is driven to rotate with respect to the photoreceptor, and the belt is not driven.

In Patent Document 1, the photoconductor is driven, but the photoconductor does not drive the belt. Further, the photoconductor is usually grounded in many cases, and no voltage is often applied. Therefore, in the conventional configuration, the toner is not electrostatically attracted to the member that drives the belt, and the problem that the drive member and the belt slide relative to each other hardly occurs.
On the other hand, in Example 1, a voltage is applied to the backup roll T2a, and the backup roll T2a drives the intermediate transfer belt B. Therefore, the toner is easily attracted electrostatically to the backup roll T2a, but the toner attracted to the backup roll T2a is removed by the cleaning member 11.

  Therefore, compared with the conventional structure which does not have the cleaning member which cleans backup roll T2a, in the structure of Example 1, the frictional force fall of the surface of backup roll T2a is reduced. Therefore, the relative slip generated between the backup roll T2a and the intermediate transfer belt B is reduced. Therefore, in the configuration of the first exemplary embodiment, it is possible to stabilize the behavior of the intermediate transfer belt B when rotating, and image quality such as positional deviation, color deviation, and banding of an image transferred onto the intermediate transfer belt B is reduced. Generation can be reduced.

  In the first embodiment, the cleaning member 11 is pressed against the backup roll T2a, and the cleaning member 11 is driven to rotate as the backup roll T2a is driven. Here, when the cleaning member rotates independently with respect to driving of the driving member, or when the cleaning member 11 is in contact with the backup roll T2a with a weak force, between the driving member and the cleaning member. There may be differences in the speed of the surface.

When a difference in surface speed occurs between the driving member and the cleaning member, the toner adhering to the driving member is rubbed and fixed to the surface of the driving member as the cleaning member is driven, and the driving member There was a risk that the surface frictional force would be reduced.
On the other hand, in Example 1, the cleaning member 11 is driven to rotate as the backup roll T2a is driven, and the difference in surface speed between the backup roll T2a and the cleaning member 11 hardly occurs. Therefore, compared with the case where a difference occurs in the surface speed, in the configuration of the first embodiment, the rubbing of the toner of the cleaning member 11 against the backup roll T2a is reduced. Therefore, it is possible to reduce a decrease in frictional force on the surface of the backup roll T2a.

  Moreover, in Example 1, the cleaning material 14 which comprises the roll part 13 uses the foaming member made from a polyurethane which can be elastically deformed. Therefore, when the cleaning member 11 comes into contact with the backup roll T2a with a preset bite amount, the main body 2 of the roll of the backup roll T2a bites into the roll part 13 at the contact portion between the backup roll T2a and the roll part 13. Deform. Therefore, the contact area between the roll main body 2 and the roll part 13 is expanded. Therefore, compared with the case where the amount of biting of the cleaning member 11 with respect to the backup roll T2a is small, in the configuration of the first embodiment, the cleaning member 11 is easily driven and rotated, and the rubbing is reduced. It is possible to increase the cleaning capability by increasing the area to be removed.

  In the first embodiment, the toner removed from the backup roll T2a is accumulated in the roll unit 13 over time. When the toner capacity that can be collected by the cleaning member 11 is exceeded, some of the collected toner is separated from the cleaning member 11 by centrifugal force as the cleaning member 11 rotates, and the inner surface of the intermediate transfer belt B is separated. Reattach to. The toner reattached to the intermediate transfer belt B is conveyed downstream in the rotation direction of the intermediate transfer belt B as the intermediate transfer belt B rotates. When the toner adhering to the inner surface of the intermediate transfer belt B increases, the frictional force decreases, and the intermediate transfer belt B and the backup roll T2a may become relatively slippery.

On the other hand, in Example 1, voltage is applied to the primary transfer rolls T1y to T1k, and the toner attached to the inner surface of the intermediate transfer belt B is electrostatically transferred to the primary transfer rolls T1y to T1k. To be removed by adsorption.
Therefore, in the configuration of the first exemplary embodiment, the inner surface of the intermediate transfer belt B is reduced from being contaminated with toner, and the relative slip generated between the inner surface of the intermediate transfer belt B and the backup roll T2a is reduced. The

  In Example 1, even if toner adheres to the primary transfer rolls T1y to T1k, the primary transfer rolls T1y to T1k do not drive the intermediate transfer belt B, and slip between the primary transfer rolls T1y to T1k. It doesn't matter if it happens. Further, even if the electrical resistance values of the primary transfer rolls T1y to T1k and the intermediate transfer belt B vary, it is possible to cope with voltage control. Further, compared to the primary transfer rolls T1y to T1k to which a voltage is applied, the toner hardly adheres to the tension roll Rt or the like to which no voltage is applied. If the toner is attached, the tension roll Rt and the like are driven to rotate by the intermediate transfer belt B, and the drive of the intermediate transfer belt B is hardly adversely affected.

  In the first exemplary embodiment, ribs 6 for preventing falling off are supported at both ends in the width direction of the inner peripheral surface of the intermediate transfer belt B. Moreover, in Example 1, the rib guide 3 is rotatably supported by the rotating shaft 1 of the backup roll T2a corresponding to the rib 6. The rotation radius from the center of the rotary shaft 1 is smaller on the outer surface of the small diameter portion 3c than on the outer surface of the main body 2 of the roll.

Here, if the backup roll and the guide rotate integrally, the peripheral speed of the small diameter portion is slower than the peripheral speed of the backup roll. When the intermediate transfer belt B and the rib 6 are rotated at the peripheral speed of the backup roll and the rib 6 comes into contact with the small diameter portion, the rib 6 is braked. Therefore, in the intermediate transfer belt B, a load is applied between the portion of the rib 6 and a portion other than the rib 6, and the intermediate transfer belt B may be damaged.
On the other hand, in Example 1, the rib guide 3 rotates independently with respect to the main body 2 of the roll. Therefore, when the small diameter portion 3 c comes into contact with the rib 6, the small diameter portion 3 c rotates at the same speed as the rib 6. Therefore, a load is hardly generated on the intermediate transfer belt B, and the intermediate transfer belt B is prevented from being damaged.

In the first embodiment, the front and rear ends of the roll portion 13 of the cleaning member 11 are disposed on the inner side in the front and rear direction than the front and rear ends of the roll body 2. Therefore, the rib guide 3 is not in contact with the roll portion 13.
Here, in the cleaning member, if the length of the roll portion in the axial direction is long and comes into contact with the rib guide 3, the rib guide is in contact with the cleaning member as the cleaning member rotates following the rotation of the main body 2 of the roll. 3 also rotates following. As a result, the roll body 2 and the rib guide 3 rotate integrally. Therefore, in this case, the intermediate transfer belt B may be destroyed.
On the other hand, in the first embodiment, when the backup roll T2a is driven, the roll body 2 and the rib guide 3 do not rotate integrally via the cleaning member 11, and the rib guide 3 is attached to the roll body 2. It can rotate independently. Therefore, the rib 6 is not braked and the intermediate transfer belt B is prevented from being damaged.

(Experimental example 1)
Next, an experiment was conducted to confirm the effect of the configuration of Example 1 of the present invention.
In Example 1, a member having a diameter of 14.9 [mm] made of EPDM rubber was used as the backup roll T2a.
As the cleaning member 11, a polyurethane foam member having a width of 11 [mm] and a thickness of 2.3 [mm] on the surface of the rotating shaft 1 made of SUS with an inclination of 26 [deg.] With respect to the axial direction of the cleaning shaft 12 is used. Was used in which the roll part 13 was formed by being wound twice in a spiral.
As the primary transfer rolls T1y to T1k, SUS members were used.

  In Experimental Example 1, the image density was set to 5% image, the recording sheet S was set to A4LEF, and the process speed as the printing speed was set to 308 [mm / s]. As transfer conditions, primary transfer rolls T1y to T1k were applied with a constant current control of +10 to +30 [μA], and a voltage of −1000 to −4000 [V] was applied to the backup roll T2a.

(Experimental Example 1-1)
In Experimental Example 1-1, the friction coefficient of the surface of the backup roll T2a was obtained by driving the backup roll T2a with the amount of biting of the cleaning member 11 into the backup roll T2a set to 0.8 [mm].
(Experimental example 1-2)
In Experimental Example 1-2, the friction coefficient of the surface of the backup roll T2a is obtained by driving the backup roll T2a in a state where the amount of biting corresponding to the backup roll T2a is set to 0.5 [mm]. It was.

(Experimental Example 1-3)
In Experimental Example 1-3, in a state where the amount of biting corresponding to the backup roll T2a by the cleaning member 11 is set to 0.3 [mm], the backup roll T2a is driven to obtain the friction coefficient of the surface of the backup roll T2a. It was.
(Comparative Example 1-1)
In Comparative Example 1-1, the friction coefficient of the surface of the backup roll T2a was obtained by driving the backup roll T2a with the cleaning member 11 separated from the backup roll T2a and without the cleaning member 11 disposed.

FIG. 7 is an explanatory diagram of a method for measuring the friction coefficient of the backup roll surface in Experimental Example 1.
In Experimental Example 1, a weight 102 having a mass m was attached to one end of the string 101 as shown in FIG. Then, the backup roll T2a in a fixed state, in contacting the cord 101 at a contact angle theta (wound) state was measured by a push-pull gauge was connected to a force F ₁ at the other end of the strap 101 to the other end . Then, using the following Euler belt equation (1), the friction coefficient of the surface of the backup roll T2a was measured.
μ = {ln (F ₁ / m)} / θ (1)

FIG. 8 is a list showing the experimental results of Experimental Example 1, in which the horizontal axis represents the number of running media and the vertical axis represents the friction coefficient of the surface of the driving member in the experimental example and the comparative example.
In FIG. 8, when the number of running media is 100 [kpv], in Experimental Example 1-1 and Experimental Example 1-2, the friction coefficient did not decrease with respect to the initial friction coefficient. Moreover, in Experimental example 1-3, it was about 50%, and in Comparative example 1-1, it became about 30%.

That is, as shown in Comparative Example 1-1, as compared to the conventional configuration in which the cleaning member 11 is not disposed, as shown in Experimental Example 1-1 and Experimental Example 1-2, the cleaning member 11 is applied to the backup roll T2a. It was confirmed that the friction coefficient does not decrease in a configuration in which the set value of the bite amount is sufficiently large. This is because the contact area between the backup roll T2a and the cleaning member 11, that is, the so-called nip amount is increased, the cleaning ability is improved, the toner attached to the backup roll T2a is removed, and the cleaning member 11 and the backup roll T2a are unlikely to generate a peripheral speed difference, and the toner does not easily adhere to the surface of the backup roll T2a.
In contrast to the conventional configuration in which the cleaning member 11 is not disposed as shown in Comparative Example 1-1, the set value of the amount of biting into the backup roll T2a of the cleaning member 11 is set as shown in Experimental Example 1-3. Even in a small configuration, it was confirmed that the decrease in the friction coefficient was reduced as compared with the conventional configuration in which the cleaning member 11 is not disposed as shown in Comparative Example 1-1.

(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 made in the range of the summary of this invention described in the claim. Is possible. Modification examples (H01) to (H011) of the present invention are exemplified below.
(H01) In the above-described embodiment, the copying machine U as an example of the image forming apparatus is illustrated. However, the present invention is not limited to this, and can be applied to a printer, a FAX, or a multifunction machine having a plurality of these functions. Further, although a configuration capable of forming images of four colors Y, M, C, and K has been presented, the present invention is not limited to this. The present invention can be applied to an image forming apparatus having three colors or less, a single color, or five colors or more.

(H02) In the above-described embodiment, the configuration in which the primary transfer rolls T1y to T1k are also used as the recovery member has been illustrated, but is not limited thereto. For example, separately from the primary transfer rolls T1y to T1k, it is also possible to apply a voltage to the rolls Rt, Rf, and Rw that are driven to rotate and also to be used as a collection member. In addition, a configuration in which the recovery member is disposed on the downstream side of the backup roll T2a with respect to the rotation direction of the intermediate transfer belt B is also possible.

(H03) In the above embodiment, as an example of the main body of the cleaning member, the cleaning member 11 as an example of the cleaning member having the columnar roll portion 13 extending in the front-rear direction is illustrated, but is not limited thereto, for example, Depending on the design and specifications, cleaning members such as brushes and blades can also be used.
(H04) In the above-described embodiment, the cleaning member 11 that rotates following the backup roll T2a is desirable as an example of the cleaning member, but a driving cleaning member can also be used.

(H05) In the embodiment, the cleaning member 11 as an example of the cleaning member is provided for the backup roll T2a as an example of the driving member to which the intermediate transfer belt B is driven and the secondary transfer voltage is applied. Although the configuration is exemplified, the configuration is not limited to this. For example, in a configuration in which a medium transfer belt is stretched around the secondary transfer roll, it is possible to apply a voltage to the secondary transfer roll and drive it, and to provide a cleaning member on the secondary transfer roll. In this case, it is also possible to apply a voltage to both the secondary transfer roll and the backup roll. In addition, in a monochromatic image forming apparatus, the transfer roll facing the photosensitive drum can be applied to a configuration for driving a transfer conveyance belt as an example of an endless belt-shaped conveyance member that conveys the medium while holding the medium on the surface. is there. The present invention can also be applied to a configuration in which a primary transfer voltage is applied and driven by a roller that supports the photosensitive belt and faces the primary transfer roll.

(H06) In the above embodiment, the number and position of the rolls T2b, Rt, Rf, T1y to T1k, Rw for stretching the intermediate transfer belt B can be arbitrarily changed according to the design and specifications.
(H07) In the above embodiment, it is desirable that the setting value of the amount of biting of the cleaning member 11 with respect to the backup roll T2a is sufficiently large, but depending on the design and specifications such as product life and acceptable image quality, A configuration in which the set value of the amount of biting is small is also possible.

(H08) In the above embodiment, the polarity of the secondary transfer voltage applied to the backup roll T2a as an example of the driving member can be changed as appropriate according to the design and specifications. For example, in the embodiment, a negatively charged toner is used and a negative secondary transfer voltage is applied to the backup roll T2a. However, a positively charged toner is used and a positive polarity is used for the backup roll T2a. It is also possible to apply a secondary transfer voltage.
(H09) In the above embodiment, it is desirable that the backup roll T2a and the rib guide 3 rotate independently. However, the backup roll T2a and the rib guide 3 can also rotate integrally. is there.

(H010) In the above embodiment, it is desirable that the cleaning member 11 and the rib guide 3 rotate independently. However, the cleaning member 11 and the rib guide 3 are made longer by increasing the axial length of the cleaning member 11. It is also possible to adopt a configuration in which the rotation and the rotation are integrally performed.
(H011) In the above-described embodiment, specific numerical values and constituent materials of each member can be arbitrarily changed according to design, specifications, and the like.

11 ... cleaning member,
B: Endless belt-like rotating body,
PR: Image carrier,
S ... medium,
T1y to T1k ... recovery member,
T2a: drive member, transfer member,
U: Image forming apparatus.

Claims (5)

An endless belt-like rotating body,
A driving member that supports and drives the endless belt-like rotating body to rotate the endless belt-like rotating body, and the driving member to which a preset voltage is applied;
A cleaning member for cleaning the drive member;
An image forming apparatus comprising: The cleaning member which can be driven and rotated in contact with the driving member;
The image forming apparatus according to claim 1, further comprising: A deposit disposed on the downstream side of the drive member with respect to the rotation direction of the endless belt-like rotating body and applied with a preset voltage, and detached from the cleaning member and attached to the endless belt-like rotating body. A recovery member for recovering,
The image forming apparatus according to claim 1, further comprising: The endless belt-like rotating body constituted by an endless belt-like image holding body that rotates while holding a visible image on the surface;
The drive member constituted by a transfer member to which a transfer voltage for transferring a visible image held on the surface of the endless belt-like image carrier to a medium is applied;
The image forming apparatus according to claim 1, further comprising: An image carrier that holds and rotates a visible image on the surface;
The drive member constituted by a transfer member to which a transfer voltage for transferring a visible image held on the surface of the image carrier to a medium is applied;
The endless belt-like rotating body that is sandwiched between the image holding member and the transfer member and is configured by an endless belt-like transport member that transports the medium while holding the medium;
The image forming apparatus according to claim 1, further comprising:

Images