JP5349262B2 - Intermediate transfer belt conveying device, image forming apparatus and image forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer belt conveying device, providing a high-quality image free from image shift by stably giving a tension to an intermediate transfer belt, and preventing meandering with simple constitution, in conveying the intermediate transfer belt, and also to provide an image forming apparatus using the same, and an image forming method. <P>SOLUTION: An intermediate transfer belt unit 6 is equipped with: the intermediate transfer belt 61 to which a toner image formed on a photoreceptor drum 3 is temporarily transferred; an intermediate transfer belt driving roller 62; an intermediate transfer belt driven roller 63; and an intermediate transfer belt tension roller 64, wherein the intermediate transfer belt tension roller 64 is provided to be displaceable in an up-and-down direction, an intermediate transfer belt conveying direction and an intermediate transfer belt width direction between the intermediate transfer belt driving roller 62 and the intermediate transfer belt driven roller 63, to thereby give a tension to the intermediate transfer belt 61 by gravity of the intermediate transfer belt tension roller 64. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an intermediate transfer belt conveying apparatus, an image forming apparatus using the same, and an image forming method, and more particularly, to image forming such as an electrostatic copying machine, a laser printer, and a facsimile machine that forms an image using toner by an electrophotographic method. The present invention relates to an intermediate transfer belt conveying device employed in the apparatus, an image forming apparatus using the same, and an image forming method.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer using an electrophotographic system, a photosensitive drum is disposed on a conveyance path that conveys a sheet while holding the sheet on a transfer belt, and a sheet on which a toner image formed on the photosensitive drum is conveyed. The image was transferred directly to the image forming apparatus using a so-called direct transfer method, and the toner image formed on the photosensitive drum was transferred to an endless intermediate transfer belt and transferred to the intermediate transfer belt. An image forming apparatus is known by a so-called indirect transfer method in which a toner image is transferred onto a sheet to create an image.

  In the case of the indirect transfer method, the toner image transferred from the photosensitive drum to the intermediate transfer belt is transferred again to the paper, so that the toner image on the photosensitive drum is transferred especially when transferring multiple color toner images in a superimposed manner. It is important to control the positional relationship between the toner image and the toner image on the intermediate transfer belt. For this purpose, it is necessary to apply an appropriate tension to the intermediate transfer belt so that the intermediate transfer belt is conveyed in a stable state without meandering.

  Specifically, in the full-color image forming apparatus, the intermediate transfer belt superimposes four color images of C, M, Y, and K in the plane, and therefore, the tension on the intermediate transfer belt is increased in the intermediate transfer belt conveying apparatus. If the hooking is unstable, there arises a problem that the intermediate transfer belt meanders and expands and contracts during conveyance of the intermediate transfer belt, resulting in image color misregistration. For example, if a misregistration of about 120 μ occurs, a color shift that can be recognized even by visual observation is obtained.

  Further, when the meandering of the transport roller for transporting the intermediate transfer belt frequently occurs, the end of the intermediate transfer belt may be damaged.

In order to solve the above conventional problems, various countermeasures have been proposed.
As a general measure for preventing meandering of the intermediate transfer belt, for example, groove portions are provided along the circumference at both ends of the conveyance roller of the intermediate transfer belt conveyance device, and the groove portion is provided on the back surface of the intermediate transfer belt. A technique is known in which an engaging rib (urethane rubber or the like is generally provided) is provided to prevent meandering in the width direction of the intermediate transfer belt (the axial direction of the conveying roller).

  In the above configuration, in order to ensure that the rib on the back surface of the intermediate transfer belt is engaged with the groove portion of the conveyance roller, it is necessary to always apply a tension of a certain value or more to the intermediate transfer belt by an elastic member or the like in the intermediate transfer belt conveyance device. there were.

However, in the above-described method, when the image forming apparatus is used for a long period of time, the ribs are worn and scraped ribs (urethane material or the like) enter the intermediate transfer belt conveyance device, thereby hindering the rotational movement of the intermediate transfer belt. There was a risk of image deterioration.
In addition, since the tension is continuously suspended from the intermediate transfer belt for a long period of time, there is a risk of causing permanent deformation and cracking of the intermediate transfer belt.

  As another measure to prevent meandering, the tension transfer to the intermediate transfer belt by the tension roller is made variable, and the idle transfer is made permanent when the image forming apparatus is idle (during operation standby). On the other hand, during image formation (intermediate transfer belt transport), the meandering state of the intermediate transfer belt is detected using an optical sensor or the like, and the tension roller is moved to adjust the alignment of the intermediate transfer belt. This is known.

  As a conventional technique, for example, in an image forming apparatus, a tension roller, a drive roller, and a secondary transfer counter roller are provided on an intermediate transfer belt, and a tension is applied to the tension roller only during image formation. Is disclosed. With this configuration, it is possible to prevent the intermediate transfer belt from being permanently deformed and to extend its life (see Patent Document 1).

  As another example, in an image forming apparatus, a conveyance belt formed in an endless shape is used to prevent the meandering control of the conveyance belt from being disabled due to a mounting error when the conveyance belt (intermediate transfer belt) is mounted. And a drive roll that is disposed at a fixed position in the axial direction and a drive roll that is tiltably disposed to adjust the meandering of the transport belt, and a movable roll that is movable in the axial direction. And a slide roll that is driven and rotated by the conveyor belt. The slide roll is provided with an elastic member that is restricted from moving in the axial direction, and the position of the conveyor belt is detected by a sensor as meandering control means. An arrangement in which the alignment of the steering roll is adjusted is disclosed (see Patent Document 2).

JP 2001-22188 A JP 2006-106194 A

  However, in the belt conveyance device of Patent Document 1, it is necessary to provide an elastic member that restricts the movement of the slide roller in the axial direction, and a tilting mechanism that tilts the steering roll, which makes the device configuration and operation control complicated. was there.

  In the image forming apparatus of Patent Document 2, it is necessary to provide a driving unit that drives an adjusting unit that adjusts the tension of the intermediate transfer belt, and a control unit that detects the tension of the intermediate transfer belt and controls the tension. There is a problem that the apparatus configuration and operation control become complicated.

  As described above, the conventional technology described above has been difficult to mount on all multifunction devices and printers from the low end to the high end in terms of mechanism design and cost.

  The present invention has been made in view of the above-described conventional problems, and in the intermediate transfer belt conveyance in the image forming apparatus, a stable tension is applied to the intermediate transfer belt with a simple configuration and the meandering is prevented. It is an object of the present invention to provide an intermediate transfer belt conveying apparatus capable of realizing a high-quality image without deviation, an image forming apparatus using the same, and an image forming method.

  In order to solve the above-described problems, an intermediate transfer belt conveying apparatus according to the present invention, an image forming apparatus using the same, and an image forming method are as follows.

The present invention provides an endless intermediate transfer belt that temporarily transfers a toner image formed on an image carrier provided in an image forming apparatus, a driving roller that conveys the intermediate transfer belt, and the intermediate roller together with the driving roller. In an intermediate transfer belt conveyance device comprising a plurality of roller members including a driven roller for suspending a transfer belt and a tension roller for applying tension to the intermediate transfer belt, the drive roller and the driven roller , An intermediate transfer belt tension roller shaft support member that supports the shaft portion of the intermediate transfer belt tension roller, a shaft support member guide that guides the movement of the intermediate transfer belt tension roller shaft support member, and the intermediate transfer belt tension roller upward. An intermediate transfer belt tension roller stopper that pushes up and holds the The chromatography la, wherein the intermediate transfer belt tension roller shaft support member and the shaft support member guide, in provided vertically displaceable in the intermediate transfer belt conveyance direction and the intermediate transfer belt width direction, the intermediate transfer belt tension roller When the conveyance of the intermediate transfer belt is stopped by the stopper, the intermediate transfer belt tension roller is temporarily held so that no tension is applied to the intermediate transfer belt, and when the intermediate transfer belt is conveyed, The holding state of the intermediate transfer belt tension roller is released, and tension is applied to the intermediate transfer belt by the weight of the tension roller.

Further, the present invention provides an image carrier on which an electrostatic latent image is formed on a surface, a charging device that charges the surface of the image carrier, an exposure device that forms an electrostatic latent image on the surface of the image carrier, An intermediate transfer belt comprising a developing device for supplying toner to the electrostatic latent image on the surface of the image carrier to form a toner image, and an intermediate transfer belt for temporarily transferring the toner image formed on the image carrier. and a conveying device, wherein in the intermediate toner image transferred to the transfer belt is transferred to a recording medium an image forming apparatus for image output, as the intermediate transfer belt conveying apparatus, the intermediate transfer belt conveyor according to claim 1 An apparatus is used.

According to the present invention, together with an endless intermediate transfer belt that temporarily transfers a toner image formed on an image carrier provided in an image forming apparatus, a drive roller that conveys the intermediate transfer belt, and the drive roller a driven roller for suspending the intermediate transfer belt, the intermediate transfer belt conveyance apparatus provided with a plurality of roller members and a tension roller that applies tension to the intermediate transfer belt, between the driving roller and the driven roller An intermediate transfer belt tension roller shaft support member that supports the shaft portion of the intermediate transfer belt tension roller, a shaft support member guide that guides the movement of the intermediate transfer belt tension roller shaft support member, and the intermediate transfer belt tension roller. An intermediate transfer belt tension roller stopper that pushes upward and holds the belt is disposed. The Yonrora, by said intermediate transfer belt tension roller shaft support member and the shaft support member guide, in the vertical direction, displacement of the intermediate transfer belt conveyance direction and the intermediate transfer belt width direction can be provided, the intermediate transfer belt tension roller stopper Thus, when the conveyance of the intermediate transfer belt is stopped, the intermediate transfer belt tension roller is temporarily held so that no tension is applied to the intermediate transfer belt, and when the intermediate transfer belt is conveyed, By releasing the holding state of the transfer belt tension roller and applying tension to the intermediate transfer belt by the weight of the tension roller, the optimum tension roller for the intermediate transfer belt according to variations in the configuration of each image forming apparatus Move by its own weight to a position where proper alignment can be maintained In, with a simple configuration stably the intermediate transfer belt can give tension, it is possible to prevent the meandering of the intermediate transfer belt. Thereby, it is possible to realize a high-quality image without image displacement.
In addition, according to the present invention, it is possible to eliminate a conventional intermediate transfer belt position detection sensor for controlling the tension of the intermediate transfer belt, a complicated tension application control mechanism, and the like, and a simple apparatus configuration can be realized. .

Further, according to the present invention, by the intermediate transfer belt tension roller stopper, when the conveyance of the pre-Symbol intermediate transfer belt is in the stopped state, so the tension is not applied to the intermediate transfer belt to temporarily hold the tension roller When the intermediate transfer belt is conveyed, the holding state of the tension roller is released and tension is applied to the intermediate transfer belt by the weight of the tension roller. Permanent distortion of the intermediate transfer belt caused by use can be suppressed. As a result, it is possible to prevent image color misregistration and prolong the life of the intermediate transfer belt.

Furthermore, according to the present invention, an image carrier on which an electrostatic latent image is formed on the surface, a charging device that charges the surface of the image carrier, and an exposure device that forms an electrostatic latent image on the surface of the image carrier. A developing device that supplies toner to the electrostatic latent image on the surface of the image carrier to form a toner image, and an intermediate transfer belt that temporarily transfers the toner image formed on the image carrier. and a transfer belt conveying device, wherein in the intermediate toner image transferred to the transfer belt is transferred to a recording medium an image forming apparatus for image output, as the intermediate transfer belt conveying device, an intermediate transfer according to claim 1 By using the belt conveyance device, it is possible to stably apply tension to the intermediate transfer belt according to variations in the configuration of individual image forming apparatuses with a simple configuration, and to prevent meandering of the intermediate transfer belt. Can. Thereby, it is possible to realize a high-quality image without image displacement.

1 is an explanatory diagram showing an overall configuration of an image forming apparatus according to an embodiment of the present invention. (A) is explanatory drawing which shows the structure of the intermediate transfer belt unit which concerns on this embodiment, (b) is AA sectional arrow directional view of (a). FIG. 4 is an explanatory diagram illustrating a state in which the intermediate transfer belt tension roller of the intermediate transfer belt unit is released. FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus. 4 is a flowchart showing an image forming process in the image forming apparatus.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is an explanatory diagram showing an overall configuration of an image forming apparatus according to an embodiment of the present invention, which is an example of an embodiment of the present invention.

  In the present embodiment, as shown in FIG. 1, a photosensitive drum (image carrier) 3 on which an electrostatic latent image is formed on a surface, a charger (charging device) 5 for charging the photosensitive drum 3, a photosensitive drum An exposure unit (exposure device) 1 that forms an electrostatic latent image on the surface of the photosensitive drum 3; and a developing device (developing device) 2 that supplies toner to the electrostatic latent image on the surface of the photosensitive drum 3 to form a toner image. And an intermediate transfer belt unit (intermediate transfer belt conveyance device) 6 provided with an intermediate transfer belt 61 for temporarily transferring the toner image formed on the photosensitive drum 3, and the toner transferred to the intermediate transfer belt 61. In the image forming apparatus 100 that transfers an image to a recording medium and outputs an image, the characteristic structure of the intermediate transfer belt conveyance device according to the present invention is adopted as the intermediate transfer belt unit 6.

First, the overall configuration of the image forming apparatus 100 according to the first embodiment will be described.
As shown in FIG. 1, the image forming apparatus 100 forms multicolor and single color images on a predetermined sheet (recording medium) in accordance with image data transmitted from the outside. The automatic document processing apparatus 120 is configured.

  The apparatus main body 110 includes an exposure unit 1, a developing device 2, a photosensitive drum 3, a cleaner unit 4, a charger 5, an intermediate transfer belt unit 6, a fixing unit 7, a paper feed cassette 81, a paper discharge tray 91, and the like. It is configured.

A document placing table 92 made of transparent glass on which a document is placed is provided on the upper portion of the apparatus main body 110, and an automatic document processing device 120 is attached to the upper side of the document placing table 92.
The automatic document processing device 120 automatically conveys the document on the document placing table 92.

Image data handled in the image forming apparatus 100 corresponds to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y).
Accordingly, four developing devices 2, photosensitive drums 3, charging devices 5, and cleaner units 4 are provided to form four types of latent images corresponding to the respective colors, and are respectively provided in black, cyan, magenta, and yellow. These are set to form four image stations.

  The charger 5 is a charging means for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential. In addition to the charger type as shown in FIG. 1, a contact type roller type or brush type charger is used. Sometimes used.

  The exposure unit 1 exposes the charged photosensitive drum 3 in accordance with image data input from the outside or image data obtained by reading from a document, thereby generating an electrostatic latent image corresponding to the image data on the photosensitive body. This is an image writing device formed on the surface of the drum 3.

  The exposure unit 1 is configured as a laser scanning unit (LSU) provided with a laser emitting portion, a reflection mirror, and the like. The exposure unit 1 includes a polygon mirror that scans the laser beam and optical elements such as a lens and a mirror for guiding the laser beam reflected by the polygon mirror to the photosensitive drum 3.

  Further, as the exposure unit 1, in addition to the above-described configuration, for example, a method using an EL or LED writing head in which light emitting elements are arranged in an array can be employed.

  The exposure unit 1 configured in this manner has a function of forming an electrostatic latent image on the surface of the photosensitive drum 3 according to the image data by exposing the charged photosensitive drum 3 according to the input image data. Have.

  The developing unit 2 visualizes the electrostatic latent images formed on the respective photosensitive drums 3 with toners of four colors (Y, M, C, K).

  The photosensitive drum 3 has a cylindrical shape, is disposed above the exposure unit 1, the surface thereof is cleaned by the cleaner unit 4, and the cleaned surface is uniformly charged by the charger 5.

  The cleaner unit 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

  The intermediate transfer belt unit 6 according to this embodiment includes an endless intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer belt tension roller 64, an intermediate transfer roller 65, and an intermediate transfer belt cleaning. A unit 66 is provided. Four intermediate transfer rollers 65 are provided corresponding to the respective colors for Y, M, C, and K.

  The intermediate transfer belt drive roller 62, the intermediate transfer belt driven roller 63, the intermediate transfer belt tension roller 64, and the intermediate transfer roller 65 are configured so as to rotate around the intermediate transfer belt 61.

  Each intermediate transfer roller 65 provides a transfer bias for transferring the toner image on the photosensitive drum 3 onto the intermediate transfer belt 61.

  The intermediate transfer belt 61 is formed in an endless shape using a film having a thickness of about 100 μm to 150 μm, and is provided so as to contact each photosensitive drum 3. A function of forming a color toner image (multicolor toner image) on the intermediate transfer belt 61 by sequentially superimposing and transferring the toner images of the respective colors formed on the photosensitive drum 3 onto the intermediate transfer belt 61. have.

  The transfer of the toner image from the photosensitive drum 3 to the intermediate transfer belt 61 is performed by an intermediate transfer roller 65 that is in contact with the back side of the intermediate transfer belt 61.

  Each intermediate transfer roller 65 applies a transfer bias for transferring the toner image on the photosensitive drum 3 onto the intermediate transfer belt 61 with respect to the intermediate transfer belt 61. Specifically, a high-voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 65 in order to transfer the toner image.

  The intermediate transfer roller 65 is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). With this conductive elastic material, a high voltage can be uniformly applied to the intermediate transfer belt 61. In this embodiment, the roller-shaped intermediate transfer roller 65 is used as the transfer electrode, but a brush or the like can also be used.

  As described above, the toner images visualized according to the hues on the photosensitive drums 3 are stacked on the intermediate transfer belt 61. The toner images as the stacked image information are conveyed together with the intermediate transfer belt 61 and transferred onto the sheet by the transfer roller 10 disposed at the contact position between the conveyed sheet and the intermediate transfer belt 61.

  At this time, the intermediate transfer belt 61 and the transfer roller 10 are pressed against each other at a predetermined nip, and a voltage (secondary transfer bias) for transferring the toner to the sheet is applied to the transfer roller 10. This voltage is a high voltage having a polarity (+) opposite to the charging polarity (−) of the toner.

  Furthermore, in order to obtain the above nip constantly, the transfer roller 10 uses either the transfer roller 10 or the intermediate transfer belt drive roller 62 as a hard material (metal or the like) and the other as a soft material such as an elastic roller (an elastic rubber roller). Or a foaming resin roller, etc.).

  In the transfer process described above, the toner attached to the intermediate transfer belt 61 by contacting the photosensitive drum 3 or the toner remaining on the intermediate transfer belt 61 without being transferred onto the sheet by the transfer roller 10 is the next process. Therefore, the toner image is removed and collected by the intermediate transfer belt cleaning unit 66.

  The intermediate transfer belt cleaning unit 66 is provided on the downstream side of the transfer roller 10 and upstream of the photosensitive drum 3 in the intermediate transfer belt conveyance direction on the path along which the intermediate transfer belt 61 is conveyed.

  The intermediate transfer belt cleaning unit 66 includes a cleaning blade 66a as a cleaning member that contacts the intermediate transfer belt 61 and cleans the surface of the intermediate transfer belt 61, and the intermediate transfer belt 61 that contacts the cleaning blade 66a includes: It is supported by an intermediate transfer belt drive roller 62 from the back side.

  The paper feed cassette 81 is a tray for storing sheets used for image formation, and is provided below the exposure unit 1 of the apparatus main body 110. A manual paper feed cassette 82 capable of supplying sheets from the outside is provided on the outer side of the apparatus main body 110. A plurality of sheets used for image formation can be stacked on the manual sheet feeding cassette 82. A paper discharge tray 91 for stacking printed sheets face down is provided above the apparatus main body 110.

  Further, the apparatus main body 110 has a substantially vertical sheet conveyance path (sheet) for feeding the sheets of the sheet feeding cassette 81 and the manual sheet feeding cassette 82 to the sheet discharge tray 91 via the transfer roller 10 and the fixing unit 7. A conveyance path) S is provided. In the vicinity of the paper transport path S from the paper feed cassette 81 or the manual paper feed cassette 82 to the paper discharge tray 91, pickup rollers 11a and 11b, a plurality of transport rollers 12a to 12d, a registration roller 13, a transfer roller 10, and a fixing roller. Unit 7 etc. are arranged.

  The conveyance rollers 12 a to 12 d are small rollers for promoting and assisting conveyance of the sheet, and a plurality of conveyance rollers 12 a to 12 d are provided along the sheet conveyance path S. The conveyance roller 12b functions as a discharge roller that discharges the sheet to the discharge tray 91, and is therefore referred to as a discharge roller.

The pickup roller 11 a is provided near the end of the paper feed cassette 81, picks up sheets one by one from the paper feed cassette 81, and supplies them to the paper transport path S.
The pickup roller 11 b is provided near the end of the manual paper feed cassette 82, picks up sheets one by one from the manual paper feed cassette 82, and supplies them to the paper transport path S.

  The registration roller 13 temporarily holds the sheet being conveyed on the sheet conveyance path S. The sheet has a function of conveying the sheet to the transfer roller 10 at the timing when the leading edge of the toner image on the photosensitive drum 3 and the leading edge of the sheet are aligned. That is, the registration roller 13 aligns the toner image on the intermediate transfer belt 61 at a predetermined position on the conveyed sheet.

  The fixing unit 7 includes a heat roller 71 and a pressure roller 72, and the heat roller 71 and the pressure roller 72 are configured to rotate and convey the sheet therebetween.

  The heat roller 71 and the pressure roller 72 are disposed to face each other, and a fixing nip portion is formed at a pressure contact portion between the heat roller 71 and the pressure roller 72.

  The heat roller 71 is set by the control unit to reach a predetermined fixing temperature based on a signal from a temperature detector (not shown). The heat roller 71 has a function of fusing, mixing, and pressing the multicolor toner image transferred to the sheet and thermally fixing the sheet to the sheet by thermocompression bonding the toner to the sheet together with the pressure roller 72. ing. An external heating belt 73 for heating the heat roller 71 from the outside is provided.

Next, a sheet conveying operation by the sheet conveying path S in the image forming apparatus 100 will be described.
As shown in FIG. 1, the image forming apparatus 100 is provided with a paper feed cassette 81 that stores sheets in advance and a manual paper feed cassette 82 as described above. Pickup rollers 11a and 11b are arranged in the paper feed cassettes 81 and 82, respectively, and the pickup rollers 11a and 11b guide sheets one by one from the paper feed cassettes 81 and 82 to the paper transport path S.

  In the case of the single-sided printing request, the sheet conveyed from each of the sheet feeding cassettes 81 and 82 is conveyed to the registration roller 13 by the conveying roller 12a in the sheet conveying path S. The registration roller 13 conveys the leading edge of the sheet and the leading edge of the image information on the intermediate transfer belt 61 to the transfer roller 10 at a timing to align the image information (toner image) on the intermediate transfer belt 61 onto the sheet. The

  The sheet on which the toner image is transferred passes through the fixing unit 7 so that the unfixed toner on the sheet is melted and fixed by heat. Then, the paper is discharged onto a paper discharge tray 91 through a conveyance roller 12b disposed on the downstream side of the fixing unit 7.

  On the other hand, in the case of the double-sided printing request, the trailing edge of the sheet that has finished the single-sided printing and has passed through the fixing unit 7 as described above is held by the final conveying roller 12b. Next, the sheet is guided to the transport rollers 12c and 12d by the reverse rotation of the transport roller 12b. Then, after printing is performed again on the back side of the sheet through the registration roller 13, the sheet is discharged to the discharge tray 91.

Next, the structure of the characteristic intermediate transfer belt unit 6 of this embodiment will be described in detail with reference to the drawings.
2A is an explanatory view showing the configuration of the intermediate transfer belt unit according to the present embodiment, FIG. 2B is a sectional view taken along the line AA of FIG. 3A, and FIG. 3 is an intermediate transfer belt of the intermediate transfer belt unit. It is explanatory drawing which shows the state which cancel | released holding | maintenance of the tension roller.

  As shown in FIG. 2A, the intermediate transfer belt unit 6 includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer belt tension roller 64, an intermediate transfer roller 65, an intermediate transfer roller. In addition to the belt cleaning unit 66, an intermediate transfer belt tension roller shaft support member 67, a shaft support member guide 68, and an intermediate transfer belt tension roller stopper 69 are provided.

  In order to prevent the intermediate transfer belt 61 from meandering in the width direction of the intermediate transfer belt 61 (the axial direction of the intermediate transfer belt roller) in the intermediate transfer belt unit 6, for example, as shown in FIG. Further, urethane guide ribs 61a may be provided on the back surface of the intermediate transfer belt 61 in the width direction.

  In the present embodiment, four intermediate transfer rollers 65 are provided corresponding to the respective colors for Y, M, C, and K.

  The intermediate transfer belt drive roller 62, the intermediate transfer belt driven roller 63, the intermediate transfer belt tension roller 64, and the intermediate transfer roller 65 are driven to rotate with the intermediate transfer belt 61 stretched.

  The intermediate transfer belt tension roller 64 is disposed so as to apply tension from the inside of the intermediate transfer belt 61 between the intermediate transfer belt driving roller 62 and the intermediate transfer belt driven roller 63.

  Further, since the intermediate transfer belt tension roller 64 adjusts the tension and alignment of the intermediate transfer belt 61 by its own weight, a weight is added to the roller so that its own weight is at least 1 kg or more. The intermediate transfer belt tension roller 64 is preferably heavier than the intermediate transfer belt driving roller 62 and the intermediate transfer belt driven roller 63.

  The shaft portion 64 a of the intermediate transfer belt tension roller 64 is disposed in an intermediate transfer belt tension roller shaft support member 67 that does not restrict the movement of the intermediate transfer belt tension roller 64 in the vertical direction, the horizontal direction, and the front-rear direction.

  The intermediate transfer belt tension roller shaft support member 67 is formed so that its shaft attachment portion is about 1 mm larger than the outer periphery of the shaft portion 64 a of the intermediate transfer belt tension roller 64. The intermediate transfer belt tension roller shaft support member 67 is guided by a shaft support member guide 68 so as to be movable in the vertical direction.

  When the image forming apparatus 100 is turned off, the intermediate transfer belt tension roller stopper 69 pushes up and holds the intermediate transfer belt tension roller 64 upward as shown in FIG. It does not hang.

  Further, the intermediate transfer belt tension roller stopper 69 keeps the intermediate transfer belt tension roller 64 held when the power of the image forming apparatus 100 is turned on and the intermediate transfer belt drive roller 62 is driven as shown in FIG. The intermediate transfer belt tension roller 64 is released so that tension is applied to the intermediate transfer belt 61 by its own weight.

  At this time, the intermediate transfer belt tension roller 64 naturally moves in the vertical direction, the intermediate transfer belt conveyance direction, and the intermediate transfer belt width direction so as to be aligned in an optimum state in accordance with the rotational drive of the intermediate transfer belt 61. To do.

Here, the configuration of the image forming apparatus 100 will be described with reference to a block diagram.
FIG. 4 is a block diagram illustrating a configuration of the image forming apparatus according to the present exemplary embodiment.

  As shown in FIG. 4, the image forming apparatus 100 includes a control unit 501, a storage unit 502, a display unit 503, an input unit 504, a LAN connection unit 505, a calculation unit 506, and image processing that control the operation of the image forming apparatus 100. An image processing unit 508 that performs image formation, an image formation unit 509 that performs image formation, a fixing unit 510 that performs toner image fixing processing, a reading unit 507 that reads an image in a scanner, a control unit 511 that controls operations of peripheral devices, and the like. ing.

  Next, image formation by the image forming apparatus 100 of the present embodiment will be described based on a flowchart. FIG. 5 is a flowchart showing image forming processing steps in the image forming apparatus of this embodiment.

  When the image forming apparatus 100 is powered off or in a standby state, as shown in FIG. 2A, in the intermediate transfer belt unit 6, the intermediate transfer belt tension roller 64 is moved by an intermediate transfer belt tension roller stopper 69. 61 is held without tension.

Image formation by the image forming apparatus 100 is performed as shown in FIG.
When the power of the image forming apparatus 100 is turned on (step S1), the control unit 501 starts the operation of the intermediate transfer belt unit 6, and the intermediate transfer belt drive roller 62 rotates (step S2). A cam (not shown) rotates with the rotation of the intermediate transfer belt driving roller 62 (step S3), and the intermediate transfer belt tension roller stopper 69 is rotated downward by the rotation of the cam, so that the intermediate transfer belt tension roller 64 is held. Is released (step S4).

At the same time as the holding state by the intermediate transfer belt tension roller stopper 69 is released, the intermediate transfer belt tension roller 64 falls downward due to its own weight (step S5).
At this time, since the intermediate transfer belt tension roller 64 is held by another holding member or the like, it can be displaced in the vertical direction, the intermediate transfer belt conveyance direction, and the intermediate transfer belt width direction.

  Then, the intermediate transfer belt 61 is stretched by the intermediate transfer belt tension roller 64, and the image forming apparatus 100 enters the ready state (step S6).

  Next, when a copy or print job is input via the input unit 504, the reading unit 507, etc. (step S7), tension control automatic alignment adjustment by the intermediate transfer belt tension roller 64 is started (step S8). That is, the intermediate transfer belt tension roller 64 is automatically moved by its own weight to the optimum position where the running balance of the intermediate transfer belt 61 is most uniform in the intermediate transfer belt unit 6 as the intermediate transfer belt 61 moves.

Then, the control unit 501 starts a printing operation, and an image is formed on the sheet by the image processing unit 508, the image forming unit 509, and the fixing unit 510 (step S9).
In this way, image formation by the image forming apparatus 100 is performed.

  Then, the energization state of the image forming apparatus 100 is confirmed (step S10). If it is determined in step S10 that the power is ON, the process returns to step S5 and image formation is continued.

On the other hand, if it is determined in step S10 that the power has been turned off, a cam (not shown) is rotated (step S11), the intermediate transfer belt tension roller stopper 69 is rotated upward (step S12), and the intermediate transfer belt. The tension roller 64 is returned to the standby position and is held away from the intermediate transfer belt 61 (step S13).
In this way, the image forming process by the image forming apparatus 100 ends.

  As described above, according to the present embodiment, the intermediate transfer belt unit 6 in the image forming apparatus 100 includes the intermediate transfer belt tension roller shaft support member 67, the shaft support member guide 68, and the intermediate transfer belt tension roller. A stopper 69 is provided, and the intermediate transfer belt tension roller 64 is disposed between the intermediate transfer belt driving roller 62 and the intermediate transfer belt driven roller 63 so as to be displaced in the vertical direction, the intermediate transfer belt conveyance direction, and the intermediate transfer belt width direction. Then, by applying tension to the intermediate transfer belt 61 by the own weight of the intermediate transfer belt tension roller 64, the intermediate transfer belt 61 moves to the position where the optimum alignment of the intermediate transfer belt tension roller 64 can be maintained with respect to the intermediate transfer belt 61. , Can give stable tension. As a result, meandering of the intermediate transfer belt 61 can be prevented, and a high-quality image without image displacement can be realized.

  Further, according to the present embodiment, the intermediate transfer belt unit 6 includes the intermediate transfer belt tension roller shaft support member 67, the shaft support member guide 68, and the intermediate transfer belt tension roller stopper 69. The intermediate transfer belt tension roller 64 can be held in a state of being separated from the intermediate transfer belt 61, and the intermediate transfer belt tension roller 64 can be easily moved on the intermediate transfer belt 61 in the vertical direction, the intermediate transfer belt conveyance direction, and the intermediate transfer. Displacement in the belt width direction can be arranged.

  Further, by configuring the intermediate transfer belt unit 6 as described above, it is possible to eliminate a conventional intermediate transfer belt position detection sensor for controlling the tension of the intermediate transfer belt, a complicated tension application control mechanism, and the like. Thus, the device configuration can be simplified.

  According to this embodiment, when the conveyance of the intermediate transfer belt 61 is stopped, the intermediate transfer belt tension roller 64 is temporarily held so that the intermediate transfer belt 61 is not tensioned, and the intermediate transfer belt 61 is When transported, the holding state of the intermediate transfer belt tension roller 64 is released and tension is applied to the intermediate transfer belt 61 by the weight of the intermediate transfer belt tension roller 64, so that the intermediate transfer belt 61 is used for a long time in the same state. It is possible to suppress permanent distortion of the intermediate transfer belt 61 caused by doing so. Thereby, it is possible to prevent the color shift of the image and to extend the life of the intermediate transfer belt 61.

  In the above-described embodiment, an example in which the characteristic configuration of the intermediate transfer belt unit 6 according to the present invention is applied to the image forming apparatus 100 as shown in FIG. 1 has been described. However, an intermediate transfer belt tension roller 64 is used. As long as the image forming apparatus uses an intermediate transfer belt conveying device in which tension is applied to the intermediate transfer belt 61, the image forming apparatus and the copying machine having the above-described configuration are not limited to the above, and other images may be used. It can be developed on a forming apparatus or the like.

  As described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope not departing from the gist of the present invention are also included in the technical scope of the present invention.

1 Exposure unit (exposure equipment)
2 Developer (Developer)
3 Photosensitive drum (image carrier)
4 Cleaner unit 5 Charger (charging device)
6 Intermediate transfer belt unit (Intermediate transfer belt conveyor)
7 Fixing Unit 61 Intermediate Transfer Belt 61a Guide Rib 62 Intermediate Transfer Belt Drive Roller (Drive Roller)
63 Intermediate transfer belt driven roller (driven roller)
64 Intermediate transfer belt tension roller (tension roller)
64a Shaft portion 65 Intermediate transfer roller 67 Intermediate transfer belt tension roller shaft support member 68 Shaft support member guide 69 Intermediate transfer belt tension roller stopper 100 Image forming apparatus 501 Control portion

Claims (2)

An endless intermediate transfer belt that temporarily transfers a toner image formed on an image carrier provided in the image forming apparatus, a driving roller that conveys the intermediate transfer belt, and the intermediate transfer belt together with the driving roller. An intermediate transfer belt conveying device comprising a plurality of roller members including a driven roller that performs tensioning and a tension roller that applies tension to the intermediate transfer belt,
An intermediate transfer belt tension roller shaft support member that supports the shaft portion of the intermediate transfer belt tension roller and a shaft support that guides the movement of the intermediate transfer belt tension roller shaft support member between the drive roller and the driven roller. A member guide and an intermediate transfer belt tension roller stopper that pushes the intermediate transfer belt tension roller upward to hold it; and
The tension roller is provided by the intermediate transfer belt tension roller shaft support member and the shaft support member guide so as to be displaced in the vertical direction, the intermediate transfer belt conveyance direction, and the intermediate transfer belt width direction,
The intermediate transfer belt tension roller stopper temporarily holds the intermediate transfer belt tension roller so that tension is not applied to the intermediate transfer belt when conveyance of the intermediate transfer belt is stopped, and the intermediate transfer belt An intermediate transfer belt conveying apparatus characterized in that when being conveyed, the intermediate transfer belt tension roller is released from a holding state and tension is applied to the intermediate transfer belt by its own weight. An image carrier on which an electrostatic latent image is formed; a charging device for charging the surface of the image carrier; an exposure device for forming an electrostatic latent image on the surface of the image carrier; A developing device for supplying toner to the electrostatic latent image to form a toner image; and an intermediate transfer belt conveying device provided with an intermediate transfer belt for temporarily transferring the toner image formed on the image carrier. In the image forming apparatus for transferring the toner image transferred to the intermediate transfer belt to a recording medium and outputting the image,
An image forming apparatus using the intermediate transfer belt conveyance device according to claim 1 as the intermediate transfer belt conveyance device.

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