JP2007298826A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an abnormal noise caused by tacking between a belt supporting roll and a belt member. <P>SOLUTION: The image forming apparatus includes: the endless belt member (B); a pair of belt supporting rolls (T2) arranged facing each other across the belt member (B); and a vibration restraining member (1) arranged near on the downstream side of the pair of belt supporting rolls (T2) in the rotating direction of the belt member (B) while coming in contact with the belt member (B). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer, a FAX, a copying machine, or a multifunction machine having all or a plurality of functions, and more particularly to an image forming apparatus having an endless belt member.

Some conventional electrophotographic image forming apparatuses include a belt member such as a photosensitive belt, an intermediate transfer belt, a sheet conveying belt, and a fixing belt. These belt members are sandwiched between a pair of belt support rolls including an inner belt roll disposed inside the belt member and an outer belt support roll disposed opposite to the inner belt support roll. For example, there are a backup roll and a secondary transfer roll that sandwich an intermediate transfer belt, a primary transfer roll and a photosensitive drum that sandwich an intermediate transfer belt, a primary transfer roll and a photoreceptor drum that sandwich a sheet conveying belt, and the like.
The pair of belt support rolls that sandwich the belt member includes a mechanism for moving between a sandwiching position for sandwiching with a predetermined sandwiching pressure (nip pressure) and a separation position for separating the inner belt support roll and the outer belt support roll. Although there are some, the number of always-contact type (always pinching type) belt support roll pairs which do not have such a mechanism is increasing due to cost reduction. However, in these apparatuses, abnormal noise and noise with periodicity may be generated when the apparatus is activated (when the power is turned on or when a job is started).

FIG. 4 is an explanatory view of the prior art, FIG. 4A is an explanatory view of a state in which the belt member is stopped, FIG. 4B is an explanatory view of a state immediately after the belt member starts to rotate, and FIG. It is explanatory drawing of the state separated from the roll.
As a result of the inventor's investigation, it was found that abnormal noise was generated for the following reasons. That is, in FIG. 4A, since the belt member 03 is clamped at a predetermined clamping pressure by the belt support roll pair (01, 02), the surface of the rubber layer of the belt support roll pair (01, 02) constituted by the rubber roll. Then, the compounding agent oozes out (so-called bleed occurs), and the rubber layer of the inner belt support roll 02 and the back surface (inner surface) of the belt member 03 are adsorbed (tucked). When the belt member 03 starts to rotate in this state, the belt member 03 rotates with the tacked portion of the belt member 03 adsorbed to the inner belt support roll 02, and the belt member 03 is pulled (see FIG. 4B). When the belt member 03 is further rotated from this state, the belt member 03 is separated from the inner belt support roll 02 (see FIG. 4C), and the belt member 03 is bounced and vibrates, thereby generating abnormal noise. Since the bleed component remains on the surface of the roll 02 for a while, the abnormal noise is periodically generated every time the bleed portion of the inner belt support roll 02 enters the clamping area 04, and the abnormal noise is stopped after a while for a while. It was.

Although it is not related to the belt member, the problem of abnormal noise due to belt vibration does not occur. However, in the technical field of image forming apparatuses, the following prior art (J01) is known as a technique for dealing with rubber roll bleeding. It is.
(J01) Technology described in Patent Document 1 (Japanese Patent Laid-Open No. 05-027615) Patent Document 1 describes a transfer roll (rubber roll) that transfers a toner image on the surface of a photoreceptor to a recording sheet. Describes a technique for preventing adhesion by interposing a toner in a transfer region opposed to each other.

JP 05-027615 A

(Problems of conventional technology)
Although it is conceivable to apply the conventional technology (J01) to a belt member such as an intermediate transfer belt, even if toner can be supplied to the surface of the intermediate transfer belt, toner is applied to the back surface (inner surface). It cannot be supplied, and tacking between the backup roll (inner belt support roll) and the intermediate transfer belt cannot be prevented. It is conceivable to arrange a device for supplying toner between the inner belt support roll and the intermediate transfer belt, but there is a problem that the number of parts increases, the cost increases, and the configuration becomes complicated. In addition to this, it is conceivable to preliminarily attach the toner to the inner belt support roll, but there is a problem that the effect decreases with time with use.

In view of the above circumstances, the present invention has the following contents (O01) and (O02) as technical problems.
(O01) Suppressing noise caused by tucking between the belt support roll and the belt member.
(O02) To prevent the generation of abnormal noise with a structure that can maintain the effect over time with a low-cost and simple structure.

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

(First invention)
In order to solve the technical problem, the image forming apparatus of the first invention is
An endless belt member (B);
A pair of belt support rolls (T2) disposed opposite to each other across the belt member (B);
A vibration suppression member (1) disposed in contact with the belt member (B) in the vicinity of the belt member (B) in the rotation direction downstream side of the belt support roll pair (T2);
It is provided with.

(Operation of the first invention)
In the image forming apparatus of the first invention having the above-described configuration requirements, the pair of belt support rolls (T2) sandwich the endless belt member (B). The vibration suppressing member (1) disposed near the downstream side in the rotation direction of the belt member (B) of the belt support roll pair (T2) is in contact with the belt member (B).
Therefore, in the image forming apparatus of the first invention, since the vibration suppressing member (1) is in contact with the belt member (B), the belt is supported when the belt member (B) is rotated by the bleed in the belt support roll pair (T2). Even if the belt member (B) is attracted to the roll pair (T2) (after being tucked) and bounced and vibrated, the vibration is suppressed. Therefore, abnormal noise due to vibration can be reduced. Further, since vibration can be prevented by the vibration suppressing member (1) disposed on the downstream side of the belt support roll pair (T2), the cost is increased due to waste of toner by supplying toner as in the prior art and the configuration. Can be prevented, and the effect of preventing vibration and noise due to tack can be maintained for a long time.

(First Embodiment 1)
An image forming apparatus according to a first aspect of the present invention is the first aspect of the first aspect of the present invention.
The belt vibration suppressing member (1) disposed inside the belt member (B) and biasing the belt member (B) from the inside to the outside;
It is provided with.
(Operation of Form 1 of the First Invention)
In the image forming apparatus according to the first aspect of the present invention having the above-described structural requirements, the belt vibration suppressing member (1) disposed inside the belt member (B) has the belt member (B) outside from the inside. Energize to. Therefore, since the belt vibration suppressing member (1) urges the belt member (B) from the inside to the outside, the belt member (B) tacked so as to be wound around the belt support roll pair (T2) is used as the belt support roll pair. (T2) can be quickly separated, and vibration can be reduced.

(First Embodiment 2)
An image forming apparatus according to a second aspect of the present invention is the first aspect of the first aspect of the present invention.
The belt vibration suppressing member (1) constituted by a cleaning member (1) for cleaning the inside of the belt member (B);
It is provided with.
(Operation of the second aspect of the first invention)
In the image forming apparatus according to the second aspect of the first invention having the above-described structural requirements, the belt vibration suppressing member (1) is constituted by a cleaning member (1) for cleaning the inside of the belt member (B). The inside of the belt member (B) can be cleaned.

The above-described present invention has the following effects (E01) and (E02).
(E01) Abnormal noise due to the tuck between the belt support roll and the belt member can be suppressed.
(E02) Generation of abnormal noise can be prevented with a structure that can maintain the effect over time with a low-cost and simple structure.

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

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention.
In FIG. 1, the image forming apparatus U includes an automatic document feeder U1 and an image forming apparatus main body (copier) U2 which supports the automatic document feeder U1 and has a platen glass PG at the upper end.
The automatic document feeder U1 sets a document feed tray TG1 on which a plurality of documents Gi to be copied are stacked and a copy position (document reading position) on the platen glass PG from the document feed tray TG1. And a document discharge tray TG2 from which the document Gi transported and conveyed is discharged.
The image forming apparatus main body U2 includes a UI (user interface) through which a user inputs an operation command signal such as a copy start, an exposure optical system A, and the like.

Reflected light from an original conveyed on the platen glass PG by the automatic original conveying apparatus U2 or an original (not shown) manually placed on the platen glass PG is passed through the exposure optical system A to a CCD ( It is converted into electrical signals of R (red), G (green), and B (blue) by a solid-state imaging device.
The IPS (Image Processing System) converts the RGB electrical signals input from the CCD into K (black), Y (yellow), M (magenta), and C (cyan) image data and temporarily stores them. The image data is output to the laser drive circuit DL as image data for forming a latent image at a predetermined timing.
When the original image is monochrome, only K (black) image data is input to the laser drive circuit DL.
The laser driving circuit DL has laser driving circuits (not shown) for the respective colors Y, M, C, and K, and a laser driving signal corresponding to the input image data is transmitted at a predetermined timing to latent image forming optics. Output to a latent image writing laser diode (not shown) of each color of the system ROS.

The toner image forming apparatuses Uy, Um, Uc, Uk arranged above the ROS form toner images of respective colors of Y (yellow), M (magenta), C (cyan), and K (black), respectively. Device.
The Y, M, C, and K laser beams Ly, Lm, Lc, and Lk emitted from the laser diodes (not shown) of the latent image forming optical system ROS are respectively transferred to the rotating image carriers PRy, PRm, PRc, and PRk. Incident.
The Y toner image forming apparatus Uy includes a rotating image carrier PRy, a charging roll CRy, a developing apparatus Gy, a transfer roll T1y, and a cleaner CLy. The configuration is the same as that of the Y toner image forming apparatus Uy.

FIG. 2 is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment.
1 and 2, the image carriers PRy, PRm, PRc, and PRk are uniformly charged by the respective charging rolls CRy, CRm, CRc, and CRk, and then the image writing positions Q1y, Q1m, Q1c, At Q1k, an electrostatic latent image is formed on the surface of the laser beam Ly, Lm, Lc, Lk. The electrostatic latent images on the surfaces of the image carriers PRy, PRm, PRc, and PRk are developed into toner images by developing units Gy, Gm, Gc, and Gk in the development areas Q2y, Q2m, Q2c, and 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. Primary transfer rolls T1y, T1m, T1c, and T1k arranged on the back side of the intermediate transfer belt B in the primary transfer regions Q3y, Q3m, Q3c, and Q3k are supplied with a predetermined value from a power supply circuit E controlled by a controller C A primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied at the timing.
The toner images on the image carriers PRy to PRk are primarily transferred to the intermediate transfer belt B by the primary transfer rolls T1y, T1m, T1c, and T1k. Residual toner on the surface of the image carrier PRy, PRm, PRc, PRk after the primary transfer is cleaned by the image carrier cleaners CLy, CLm, CLc, CLk.

  Above the image carriers PRy to PRk, a belt module BM that can move up and down and can be pulled out forward is disposed. The belt module BM includes a belt support roll (Rd, Rt, Rw, Rf) including the intermediate transfer belt B, a belt drive roll Rd, a tension roll Rt, a walking roll Rw, an idler roll (free roll) Rf, and a backup roll T2a. , T2a) and the primary transfer rolls T1y, T1m, T1c, T1k. The intermediate transfer belt B is rotatably supported by the belt support rolls (Rd, Rt, Rw, Rf, T2a). Therefore, an intermediate transfer belt driving device, that is, a transfer material that conveys an intermediate transfer material (intermediate transfer belt) by the drive device that rotationally drives the drive roll Rd and the belt support rolls (Rd, Rt, Rw, Rf, T2a) and the like. Conveying devices (Rd, Rt, Rw, Rf, T2a) are configured.

  In FIG. 2, on the inner side of the intermediate transfer belt B, the vibration suppressing member 1 is rotatably supported in the vicinity of the downstream side of the backup roll T2a in the belt rotation direction. The vibration suppressing member 1 is constituted by a tension roll that urges the intermediate transfer belt B from the inside to the outside. The vibration suppressing member 1 of Example 1 is disposed at a position 20 mm downstream of the backup roll T2a in the belt rotation direction, and is configured by a urethane foam roll (Asker C hardness is 20 degrees). In addition, the vibration suppressing member 1 according to the first exemplary embodiment also has a function as a cleaning roll that cleans the inside of the intermediate transfer belt B.

A secondary transfer roll T2b is disposed facing the surface of the intermediate transfer belt B in contact with the backup roll T2a, and a secondary transfer device (belt support roll pair, transfer roll pair) T2 is formed by the rolls T2a and T2b. It is configured. Further, a secondary transfer region Q4 is formed in a region where the secondary transfer roll T2b and the intermediate transfer belt B are opposed to each other.
The secondary transfer roll T2b of Example 1 is configured by a urethane foam single-layer roll (Asker C hardness is 35 degrees) and does not have a mechanism for separating from the intermediate transfer belt B. Further, the backup roll T2a of Example 1 is made of epichlorohydrin.
The color toner images sequentially transferred onto the intermediate transfer belt B by the transfer devices T1y, T1m, T1c, and T1k in the primary transfer areas Q3y, Q3m, Q3c, and Q3k are conveyed to the secondary transfer area Q4. .

  Below the ROS, a pair of left and right guide rails GR and GR for supporting the paper feed trays TR1 to TR3 so as to be able to enter and exit in the front-rear direction (X-axis direction) are provided in three stages. The recording sheets (final transfer material) S in the paper feed trays TR1 to TR3 are taken out by the pickup roll Rp, separated one by one by the separating roll Rs, and then sent to the registration roll Rr by a plurality of transport rolls Ra. A plurality of the sheet conveying rolls Ra are provided along a sheet conveying path SH formed by a sheet guide, and a registration roll Rr is disposed upstream of the secondary transfer region Q4 in the sheet conveying direction. A sheet conveying device (SH + Ra + Rr) is configured by the sheet conveying path SH, the sheet conveying roll Ra, the registration roll Rr, and the like.

The registration roll Rr conveys the recording sheet S to the secondary transfer area Q4 in time with the timing when the color toner image formed on the intermediate transfer belt B is conveyed to the secondary transfer area Q4. When the recording sheet S passes through the secondary transfer region Q4, the backup roll T2a is grounded, and the secondary transfer roll T2b is charged with the toner charging polarity at a predetermined timing from the power supply circuit E controlled by the controller C. A secondary transfer voltage having a reverse polarity is applied. At this time, the color toner image on the intermediate transfer belt B is transferred to the recording sheet S by the secondary transfer device T2.
The intermediate transfer belt B after the secondary transfer is cleaned by a belt cleaner CLb.

The recording sheet S on which the toner image is secondarily transferred is conveyed to a fixing area Q5 which is a pressure contact area of the heating roll Fh and the pressure roll Fp of the fixing device F, and is heated and fixed when passing through the fixed area. Thereafter, the sheet is discharged from the discharge roller Rh to the discharge tray TRh.
Note that a release agent for improving the releasability of the recording sheet S from the heating roll is applied to the surface of the heating roll Fh by a release agent application device Fa.

  Above the belt module BM, developer cassettes Ky, Km, Kc, and Kk for storing Y (yellow), M (magenta), C (cyan), and K (black) developers are arranged. The developers contained in the developer cassettes Ky, Km, Kc, and Kk are supplied from the developer replenishment path (not shown) to the developer units Gy according to consumption of the developer in the developer units Gy, Gm, Gc, and Gk. , Gm, Gc, Gk.

In FIG. 1, the image forming apparatus U has an upper frame UF and a lower frame LF, and members (image carriers PRy, PRm arranged above the ROS and ROS) are disposed on the upper frame UF. , PRc, PRk, developing devices Gy, Gm, Gc, Gk, belt module BM, etc.).
The lower frame LF includes a guide rail GR that supports the paper feed trays TR1 to TR3, and the paper feed members (pickup roll Rp, separation roll Rs, and sheet transport roll) that feed paper from the trays TR1 to TR3. Ra, etc.) are supported.

(Operation of Example 1)
FIG. 3 is a diagram for explaining the operation of the first embodiment.
In the image forming apparatus U of Example 1 having the above-described configuration, bleeding may occur in the backup roll T2b due to the clamping pressure between the secondary transfer roll T2b and the backup roll T2a. However, since the vibration suppressing member 1 is disposed in the vicinity of the backup roll T2b on the downstream side in the belt rotation direction, the intermediate transfer belt B adsorbed (tucked) to the backup roll T2a immediately after the start of rotation of the belt B (FIG. 3). Are separated by the urging force of the vibration suppressing member 1 (see the solid line in FIG. 3). Accordingly, the amount of the intermediate transfer belt B that has been tucked into the backup roll T2a is reduced, so that the vibration is reduced and the generated abnormal noise can be reduced.

Further, since the vibration suppressing member 1 is constituted by a tension roll, even if the intermediate transfer belt B vibrates, the vibration suppressing member 1 can contact the intermediate transfer belt B due to the tension. Accordingly, the generated vibration of the intermediate transfer belt B is also damped by the vibration suppressing member 1 that contacts the intermediate transfer belt B, so that the vibration is quickly settled and abnormal noise can be quickly contained.
Furthermore, in the image forming apparatus according to the first embodiment, the vibration suppressing member 1 is also used as a cleaning roll. Therefore, the primary transfer rolls T1y to T1k are soiled by the dirt on the back surface of the intermediate transfer belt B, and the primary transfer is normal. Therefore, it is possible to suppress image quality deterioration (defect) such as density reduction.

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

(H02) In the above-described embodiment, the roll-shaped vibration suppressing member 1 has been exemplified. However, the present invention is not limited to this, and any pad-shaped vibration suppressing member, brush-shaped (preferably high-density brush) vibration suppressing member, or the like can be used. The shape can be adopted. Moreover, although it is desirable to comprise a tension roll, it can also be a fixed roll.
(H03) In the above embodiment, the intermediate transfer belt B is exemplified as the belt member, and the secondary transfer device T2 is exemplified as the belt support roll pair. However, the present invention is not limited thereto, and the photosensitive belt (toner image carrying belt), the transfer belt, The present invention can be applied to an image forming apparatus having an arbitrary belt member such as a fixing belt and a sheet conveying belt, and a pair of rolls that clamp the belt member.
(H04) In the above-described embodiment, the vibration suppressing member 1 is disposed on the back surface (inner surface) side of the intermediate transfer belt B. However, the present invention is not limited to this, and may be provided on the front surface side.

(H05) In the above-described embodiment, the size, constituent materials, and the like of the illustrated vibration suppressing member are not limited to those illustrated, and can be arbitrarily changed according to the design and the like.
(H06) In the above embodiment, the vibration suppressing member is also used as a cleaning roll, but it is also possible to provide a cleaning member separately.
(H07) In the above-described embodiment, it is desirable to use a vibration suppressing member that biases the intermediate transfer belt, but it is also possible to use a vibration suppressing member that only contacts the intermediate transfer belt.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment. FIG. 3 is a diagram for explaining the operation of the first embodiment. FIG. 4 is an explanatory view of the prior art, FIG. 4A is an explanatory view of a state in which the belt member is stopped, FIG. 4B is an explanatory view of a state immediately after the belt member starts to rotate, and FIG. It is explanatory drawing of the state separated from the roll.

Explanation of symbols

1 ... vibration suppressing member,
1 ... cleaning member,
B ... Belt member,
T2: Belt support roll pair.

Claims (3)

An endless belt member;
A pair of belt support rolls arranged opposite to each other with the belt member interposed therebetween;
A vibration suppressing member disposed in contact with the belt member in the vicinity of the belt member rotating direction downstream side of the belt support roll pair;
An image forming apparatus comprising: The vibration suppressing member disposed inside the belt member and biasing the belt member from the inside to the outside;
The image forming apparatus according to claim 1, further comprising: The vibration suppressing member constituted by a cleaning member for cleaning the inside of the belt member;
The image forming apparatus according to claim 2, further comprising:

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