JP2006151682A - Endless carrier belt device, transfer device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carrier belt device having a constitution capable of preventing dislocation of a moving position of a belt without having influence of vibration from a driving source on a driving part of the belt, having a constitution capable of preventing dislocation of an image forming position by the dislocation of the moving position, and having a constitution capable of improving maintainability. <P>SOLUTION: This carrier belt device has a constitution for driving an endless belt 2 wrapped around a driving roller 2B and a driven roller 2A; and is characterized by setting the driving roller 2B of the endless belt 2 in the relationship of directly receiving driving force from the driving means 27 via a coupling 28 coaxially provided with an output shaft 27A of the driving means 27 and in the mutually attachable-detachable relationship, and using a DC brush motor as a driving means 27. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an endless conveyance belt device, a transfer device, and an image forming apparatus, and more particularly to a drive mechanism for preventing positional deviation between images.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a printing machine, an electrostatic latent image formed on a latent image carrier is subjected to visible image processing by a developing device, and the visible image is recorded on a recording sheet such as transfer paper. After being transferred, the copy is obtained by being carried on a recording sheet or fixing the storage.

  On the other hand, there is a configuration in which an image forming apparatus obtains a full-color image by superimposing not only a single color but also a plurality of colors. As a configuration for this, a photoconductor that is one latent image carrier A plurality of developing devices are arranged around the surface, a visible image for each color is formed on the photosensitive member, and the visible image of each color is transferred and superimposed on a primary transfer device using a transfer drum or a transfer belt. A method of batch-transferring a color image onto a recording sheet, a method of batch-transferring an image for each color on a photosensitive member and transferring it onto a recording sheet, or a plurality of photosensitive members capable of forming a visible image for each color. There is a system including a primary transfer unit that transfers a visible image from a body, and a primary transfer unit or a secondary transfer unit that superimposes and transfers to a recording sheet conveyed by this unit. Primary transfer means, so-called intermediate transfer Means there is a tandem juxtaposed photoreceptor for each color in the expanding direction includes a belt (e.g., Patent Document 1).

On the other hand, when images of a plurality of colors are superimposed, the accuracy of alignment between the images is important for preventing color misregistration.
Therefore, conventionally, the shift amount is determined by comparing the detection timing of each pattern image with the reference timing for the color shift detection pattern image prepared for each color on the belt used for the intermediate transfer unit, and the result There is a configuration in which the writing start time in the main scanning direction and the drive control of the belt are controlled according to the above (for example, Patent Document 2).

JP 2000-112205 A (paragraph “0015” column) JP 2002-182537 A (paragraph “0005” column)

  As disclosed in Patent Document 2, a stepping motor or a vibration wave motor is used as a driving mechanism used for a transfer belt of an intermediate transfer device in these image forming apparatuses including a configuration for detecting a positional shift between colors. Generally, the driving roller of the belt is driven by transmitting a driving force from a driving motor using a belt to a reduction mechanism such as a gear or a pulley by coupling.

  However, in such a drive mechanism, it is difficult not only to drive the belt in a constant and uniform state due to mechanical fluctuations of the speed reduction mechanism, but also when starting and stopping the rotation at the drive source. When the vibration is transmitted to the belt due to the large vibration, there is a possibility that the transfer position shift of each color becomes remarkable due to the speed fluctuation.

  Therefore, a method of directly transmitting the driving force from the driving source to the driving roller of the belt is conceivable. However, if the driving source and the belt driving roller are directly connected, it becomes impossible to attach and detach, thereby improving the maintainability of the machine. The problem that it cannot be made good occurs.

  An object of the present invention is to provide a belt moving position shift by preventing the influence of vibration from a driving source from affecting the belt driving unit in view of the problems in the above-described conventional belt-based conveying device, particularly a belt transfer device. It is an object of the present invention to provide a conveying belt device, a transfer device, and an image forming apparatus having a configuration capable of preventing the image forming position and a configuration capable of preventing a shift in the image forming position due to a shift in the moving position and improving the maintainability.

The invention according to claim 1 is a belt conveying device having a configuration for driving an endless belt wound around a driving roller and a driven roller.
The driving roller of the belt is set in a relationship of directly receiving a driving force from the driving unit via a coupling provided coaxially with the output shaft of the driving unit and a detachable relationship with each other, and the DC as the driving unit It is characterized by using a brush motor.

  According to a second aspect of the present invention, the belt conveying device according to the first aspect is used for a transfer device.

  According to a third aspect of the present invention, in the transfer device according to the second aspect, the belt is used as a transfer body capable of carrying an image or a recording sheet.

  The invention described in claim 4 is characterized in that the transfer device described in claim 2 or 3 is used in an image forming apparatus.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the transfer device is configured to be capable of superimposing and transferring a plurality of color images.

  According to the first aspect of the present invention, the driving roller of the endless belt is directly related to the driving force from the driving means. Specifically, the driving means generally has a low rotational speed, so that the durability is generally low. Since it is possible to use a DC brush motor that does not meet the lifetime level of the OA equipment, the driving means can be reduced in cost and increased in energy efficiency. In addition, it is possible to prevent unevenness in the speed of the endless belt by suppressing mechanical fluctuations that occur when a speed reduction mechanism or the like is interposed. Furthermore, since it is connected via a coupling between the drive roller and the output shaft of the drive means, it can be detached even if it is connected on the same axis, facilitating handling during maintenance and improving maintainability. It becomes possible to improve.

  According to the second to fifth aspects of the present invention, since the endless belt driving roller and the driving means for the endless belt are connected coaxially, the endless belt is transferred to the endless belt when used as a transfer belt. Accordingly, it is possible to eliminate the transfer position shift of the plurality of color images, and thus it is possible to obtain an image having no color shift. In addition, when performing maintenance such as belt replacement, the drive roller that is connected on the same axis and directly receives the driving force can be easily attached to and detached from the output shaft of the driving means, thereby improving maintainability. It becomes possible.

  Hereinafter, the best mode for carrying out the invention will be described with reference to embodiments shown in the drawings.

FIG. 1 shows an image forming apparatus to which a belt conveying apparatus according to an embodiment of the present invention and a transfer apparatus using the same are applied.
An image forming apparatus 1 shown in FIG. 1 has a tandem configuration in which a plurality of photoreceptors as latent image carriers capable of forming a color image corresponding to color separation are juxtaposed, and toner formed on each photoreceptor. The color printer is capable of forming a multicolor image by superimposing and transferring an image onto an intermediate transfer member and then transferring the superimposed image onto a sheet such as recording paper. In the present invention, the image forming apparatus is not limited to a color printer, but of course includes a color copying machine, a facsimile machine, and a printing machine.

In FIG. 1, in a color printer 1, an image forming unit 1A is positioned at a central portion in the vertical direction, a document feeding unit 1B is provided below the image forming unit 1A, and an original document table 1C1 is provided above the image forming unit 1A. Each of the scanning units 1C is arranged.
In the image forming unit 1A, a transfer unit 20 composed of an intermediate transfer belt 2 having a horizontally extending surface is disposed. Above the intermediate transfer belt 2, a color having a complementary color relationship with the color separation color is disposed. A configuration for forming an image is provided.

In the image forming unit 1A, photoreceptors 3B, 3Y, 3C, and 3M capable of carrying images of toners of complementary colors (yellow, magenta, cyan, and black) are juxtaposed along the extended surface of the intermediate transfer member 2. Has been. In the following description, in the case of contents common to all the photoconductors, the photoconductor is denoted by reference numeral 3.
Each of the photoconductors 3B, 3Y, 3C, and 3M is composed of a drum that can rotate in the same direction (counterclockwise in FIG. 1). A device 4, a writing device 5, a developing device 6, a primary transfer device 7 which is one of transfer bias applying means, and a cleaning device 8 are arranged (for the sake of convenience, the reference numerals of the respective devices are used for the photosensitive member 3B). B is shown).

  The transfer device 20 including the intermediate transfer belt 2 corresponds to a primary transfer portion to which a visible image from an image forming unit including each photoconductor is sequentially transferred, and is wound around a plurality of rollers 2A to 2C. The roller 2C, which is configured so as to be movable in the same direction at the position facing the photoconductor, and which is different from the rollers 2A and 2B constituting the stretched surface, faces the secondary transfer device 9 across the intermediate transfer belt 2. is doing. In this embodiment, the roller indicated by reference numeral 2A is used as a driven roller, and the roller indicated by reference numeral 2B is used as a driving roller. Further, in FIG. 1, reference numeral 10 denotes a cleaning device for the intermediate transfer belt 2.

  The secondary transfer device 9 includes a transfer belt 9C that is wound around the charging drive roller 9A and the driven roller 9B and is movable in the same direction as the intermediate transfer belt 2 at the secondary transfer position where the secondary transfer device 9 is located. The multi-color image superimposed on the intermediate transfer belt 2 in the process of transporting the recording sheet while electrostatically attracting it by charging the transfer belt 9C with the charging drive roller 9A can be transferred by single transfer or carried by a single color. Each image can be transferred to a recording sheet.

A recording sheet is fed from the paper feeding unit 1B to the secondary transfer position.
The paper feed unit 1B includes a plurality of paper feed cassettes 1B1, a plurality of transport rollers 1B2 arranged in a transport path for recording sheets fed from the paper feed cassette 1B1, and a registration roller 1B3 positioned in front of the secondary transfer position. I have. In this embodiment, in addition to the conveyance path of the recording sheet fed out from the sheet feeding tray 1B1, a recording sheet of a type not stored in the sheet feeding cassette 1B1 is fed to the sheet feeding unit 1B toward the secondary transfer position. This configuration includes a manual feed tray 1A1 and a feeding roller 1A2 provided with a part of the wall surface of the image forming unit 1A that can be turned up and down.
In the middle of the conveyance path of the recording sheet from the sheet feeding cassette 1B1 to the registration roller 1B3, the conveyance path of the recording sheet fed out from the manual feed tray 1A1 joins, and the recording sheet fed from any conveyance path is also a registration roller. Registration timing is set by 1B3.

  The writing device 5 (indicated by reference numeral 5B in FIG. 1 for convenience) has image information obtained by scanning a document on the document table 1C1 included in the document scanning unit 1C or an image output from a computer (not shown). The writing light is controlled by the information, and an electrostatic latent image corresponding to the image information is formed on the photoreceptors 3B, 3Y, 3C, and 3M.

  The document scanning unit 1C is provided with a scanner 1C2 that exposes and scans the document on the document table 1C1, and an automatic document feeder 1C3 is disposed on the upper surface of the document table 1C1. The automatic document feeder 1C3 has a configuration capable of reversing the document fed on the document table 1C1, and can perform scanning on both sides of the document.

  An electrostatic latent image formed on the photoconductor 3 (members indicated by reference numerals 3B, 3Y, 3C, and 3M in FIG. 1) formed by the writing device 5 is indicated by reference numeral 6B in FIG. 1 for convenience. ) To be subjected to a visible image processing and primary transfer to the intermediate transfer belt 2. When the toner images for the respective colors are superimposed and transferred onto the intermediate transfer belt 2, the secondary transfer device 9 performs secondary transfer on the recording sheet at once.

The unfixed image carried on the surface of the recording sheet that has been secondarily transferred is fixed by the fixing device 11. Although not shown in detail, the fixing device 11 includes a belt fixing structure including a fixing belt heated by a heating roller and a pressure roller facing and abutting the fixing belt, and the contact between the fixing belt and the pressure roller. By providing the area, that is, the nip area, the heating area for the recording sheet can be expanded as compared with the fixing structure of another roller type.
The recording sheet that has passed through the fixing device 11 is switched in the transport direction by a transport path switching claw 12 disposed behind the fixing device 11, and is transported toward the paper discharge tray 13 and reversely transported. A transport direction is selected for the path RP.

  In the color printer 1 having the above-described configuration, the document placed on the document table 1C1 is exposed and scanned, or the image of the image information from the computer is used for statically charging the photosensitive member 3. After the electrostatic latent image is formed and the electrostatic latent image is subjected to visible image processing by the developing device 6, the toner image is primarily transferred to the intermediate transfer belt 2.

  The toner image transferred to the intermediate transfer belt 2 is transferred as it is to the recording sheet fed from the paper feeding unit 1B in the case of a single color image, and the primary transfer is repeated in the case of a multicolor image. And then secondarily transferred to the recording sheet at once. The recording sheet after the secondary transfer is fixed with an unfixed image by the fixing device 11 and then fed to the paper discharge tray 13 or reversed and fed again toward the registration roller 1B3.

  In FIG. 1, although not shown in detail, the intermediate transfer belt 2 includes a base layer composed of a base portion made of a material that hardly stretches, such as a fluorine-based resin with a small elongation or a rubber material with a large elongation, and a canvas, and the like. And an elastic layer made of fluorine-based rubber or acrylonitrile-butadiene copolymer rubber provided on the upper surface. The surface of the elastic layer is provided with a coat layer that is coated with a fluororesin to improve smoothness.

The intermediate transfer belt 2 is wound around at least a pair of support rollers 2A and 2B and a roller 2C having a backup function, and is driven by the counterclockwise rotation of the drive roller 2A.
A surface extended between the support rollers 2A and 2B, that is, a plane having no curvature, faces the photoreceptors 3B, 3Y, 3C, and 3M of each image forming unit. A transfer roller 2D for electrostatically transferring a visible image on the photoconductor is disposed at a position facing each photoconductor with the intermediate transfer belt 2 interposed therebetween.

FIG. 2 is a plan view showing a main part for explaining the configuration of the transfer device 20. In FIG. 2, the transfer device 20 is installed in the casing of the color printer 1 and is on the front side of the color printer 1 (FIG. 2). Are arranged in a space constituted by a main body front frame 21 located on the lower side and a main body rear frame 22 located on the back side (upper side in FIG. 2) of the color printer 1.
That is, in the space formed by the main body front frame 21 and the main body rear frame 22, the front side plate 24 </ b> A is supported by the face plate 23 that can be attached to and detached from the positioning pins 21 </ b> A fixed to the main body front frame 21. A frame 24 in which a side plate 24B is supported by a main body rear frame 22 is disposed. The frame 24 includes a driven roller 2A, a driving roller 2B, and a backup roller 2C (not shown) around which the intermediate transfer belt 2 is wound. Each is supported rotatably.

  2, the frame 24 is supported on one side in the longitudinal direction by support pins 25 and 26 partially inserted into the main body rear frame 22 and the face plate 23, and the other side in the longitudinal direction is the rotation of the driving roller 2B of the intermediate transfer belt 2. Each end in the axial direction of the shaft 2B1 is supported by being inserted through the main body rear frame 22 and the face plate 23.

  The rotation shaft 2B1 of the driving roller 2B is positioned coaxially with the output shaft 27A of the DC brush motor 27 attached to the rear frame 22 of the main body, and directly outputs the output shaft 27A via a coupling 28 provided in a part thereof. It is supposed to be connected to

FIG. 3 is a view for explaining the configuration of the coupling 28. In FIG. 3, the coupling 28 includes a male coupling 28A and a driving roller 2B integrated with the output shaft 27A of the DC brush motor 27. It is comprised by the female side coupling 28B integrated with rotating shaft 2B1.
The male coupling 28A is formed by forming serrations on the conical cone-shaped outer diameter portion, and the female coupling 28B is serrated on the inner surface of the concave hole into which the male coupling 28A can be fitted. Serrations that can mesh with each other are formed.

  In the female side coupling 28B, the length of the insertion part of the rotating shaft 2B1 formed in the boss part is such that the output shaft 27A of the DC brush motor 27 located on the male side coupling 28A side can be inserted. Yes. For this reason, the male side coupling 28A and the female side coupling 28B are in such a relationship that the output shaft 27A can be inserted into and removed from the insertion portion 28B1 of the female side coupling 28B.

  The male and female couplings 28A and 28B are urged in a direction (thrust direction) in which they are integrated with each other by an elastic body such as a spring denoted by reference numeral 29 in FIG. A centering function when the male coupling 28A is inserted into 28B is obtained. Due to the aligning function, the output shaft 27A of the DC brush motor 27 can be easily inserted into the insertion portion 28B1 on the female coupling 28B side. The axial center position with the rotation shaft 2B1 is aligned.

Since the present embodiment has the above-described configuration, the driving roller 2B of the intermediate transfer belt 2 is directly connected to the output shaft 27A of the DC brush motor 27 without the intermediary of a reduction mechanism or the like. It is assumed that As a result, the number of rotations of the motor itself can be reduced without decelerating, so that a low cost can be achieved by using a DC brush motor whose durability is generally not suitable for this kind of OA equipment. And high energy efficiency can be ensured.
In particular, when the output shaft 27A is inserted into the female-side coupling 28B, the axial center positions of the output shaft 27A and the rotation shaft 2B1 of the drive roller 2B are made coincident and directly connected. As a result, no mechanical fluctuation occurs as in the case of using the speed reduction mechanism. In addition, by using the DC brush motor 27 as the driving means, it is possible to transmit the driving force in a state where the vibration is reduced, and the speed unevenness in the driving roller 2B is suppressed. In this case, the unevenness of the image transfer position of each color, that is, the occurrence of the color misregistration can be suppressed.

  On the other hand, since the rotary shaft 2B1 of the drive roller 2B and the output shaft 27A of the DC brush motor 27 are connected via a coupling 28 that can be attached and detached from each other, for example, the face plate 23 is removed for maintenance. In this case, the connection with the output shaft 27A can be easily released, and maintenance work can be deducted and retained. Moreover, when attaching the face plate 23 to the front frame 21 again, the output shaft 27A and the rotating shaft 2B1 of the drive roller 2B are directly connected by simply inserting the output shaft 27A on the female coupling 28B side. can do.

1 is a schematic diagram of an image forming apparatus to which a belt conveyance device according to an embodiment of the present invention and a transfer device using the same are applied. It is a figure for demonstrating the structure of the transfer apparatus using the belt conveying apparatus by the Example of this invention. FIG. 3 is a diagram for explaining a configuration of a coupling used in a belt conveyance device in the transfer device shown in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Intermediate transfer belt 2B Drive roller 2B1 Rotating shaft 3 Photoconductor 20 Transfer device 27 DC brush motor 27A Output shaft 28 Coupling 28A Male side coupling 28B Female side coupling

Claims (5)

In a belt conveying apparatus having a configuration for driving an endless belt wound around a driving roller and a driven roller,
The driving roller of the belt is set in a relationship of directly receiving a driving force from the driving unit via a coupling provided coaxially with the output shaft of the driving unit and a detachable relationship with each other, and the DC as the driving unit A belt conveying device using a brush motor.   A transfer device using the belt conveying device according to claim 1. The transfer apparatus according to claim 2, wherein the belt is used as a transfer body capable of carrying an image or a recording sheet.   An image forming apparatus using the transfer device according to claim 2. The image forming apparatus according to claim 4.
The image forming apparatus, wherein the transfer device is configured to be able to superimpose and transfer a plurality of color images.

Images