JP2008052018A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of forming a high-quality image by accurately positioning a tension roller and preventing the meandering of an intermediate transfer body. <P>SOLUTION: The image forming apparatus includes: the intermediate transfer belt 1 wound round a roller group constituted of a drive roller 2 and a support roller 3 rotatably pivotally supported by fixed shafts 5 and 6, and the tension roller 4, successively transferring respective color toner images formed on a photoreceptor so as to form a synthetic toner image and transferring the synthetic toner image to material to be transferred; and an arm 7 rotatably pivotally supporting the tension roller 4 and also rocked centering around the fixed shaft 6. Since the tension roller 4 is pivotally supported and rocked by the arm 7 rocked centering around the fixed shaft 6, a distance between the arm 7 and the tension roller 4 is kept constant regardless of the position of the tension roller 4, and the tension roller 4 is accurately positioned with the fixed shaft 6 that is the center axis of the rocking of the arm 7 as reference. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, a toner image is sequentially formed on a photosensitive member with toners of different colors, and each toner image is transferred onto an intermediate transfer member to form a composite toner image. The composite toner image is transferred from the intermediate transfer member. The present invention relates to an image forming apparatus that performs batch transfer onto a transfer material.

  Conventionally, a toner image is sequentially formed on a photoconductor with toners of different colors, and each color toner image is transferred onto an intermediate transfer belt to form a composite toner image. The composite toner image is transferred from the intermediate transfer belt. A color image forming apparatus that performs batch transfer onto a material has been developed. For example, a color image forming apparatus described in (Patent Document 1) transfers a toner image formed on a photosensitive member by a developing device for each color arranged in a row onto an intermediate transfer belt one color at a time, and is a combined toner image. And a four-pass color image forming apparatus that collectively transfers the composite toner image from the intermediate transfer belt to the transfer material.

  Further, in this type of color image forming apparatus, a toner image formed on the photoreceptor by each color of yellow, magenta, cyan, and black by a rotary developing unit is used while the intermediate transfer belt rotates once. There is a four-pass color image forming apparatus that forms a composite toner image by superimposing each color on an intermediate transfer belt. FIG. 3 is a cross-sectional view of a conventional 4-pass color image forming apparatus.

  As shown in FIG. 3, the color image forming apparatus 100 includes a rotary developing unit 101 having developing units for yellow, magenta, cyan, and black, and the rotary developing unit 101 1 A photosensitive member 102 that forms a toner image for each color, an intermediate transfer belt 103 for forming a combined toner image by transferring each color toner image formed on the photosensitive member 102 one by one, and the like are provided. In this way, in the color image forming apparatus 100 that forms a composite toner image by superimposing and transferring the toner images of the respective colors onto the intermediate transfer belt 103, it is necessary to superimpose the toner images of the respective colors at accurate positions. Tension is applied to the intermediate transfer belt 103 so as not to loosen.

  In the example of FIG. 3, the intermediate transfer belt 103 is wound around a drive roller 104 and an idle roller 105, and tension is applied by a tension roller 106 so as not to loosen. The tension roller 106 is supported at both ends of the shaft so as to move in a direction perpendicular to the surface of the intermediate transfer belt 103 stretched between the driving roller 104 and the idle roller 105, and both ends of the shaft are respectively springs. The intermediate transfer belt 103 is biased from the inner side to the outer side by 106a.

  Further, in this color image forming apparatus 100, the composite toner image formed on the intermediate transfer belt 103 is pressed against the sheet S fed from the sheet feeding cassette 107 and pressed toward the driving roller 104, so that A transfer roller 108 for transferring to S and a cleaning means 109 for removing residual toner on the intermediate transfer belt 103 by contacting the intermediate transfer belt 103 are provided.

  In this color image forming apparatus 100, a toner image is formed on the photosensitive member 102 by the developing unit 101 for each color and transferred onto the intermediate transfer belt 103. This operation is repeated for four colors of yellow, magenta, cyan, and black to form a composite toner image. At this time, since the intermediate transfer belt 103 rotates four times, the transfer roller 108 and the cleaning unit 109 are separated from the intermediate transfer belt 103 when the composite toner image is formed.

In addition, the color image forming apparatus 100 includes independent drive mechanisms 110 and 120 for the contact and separation operations of the transfer roller 108 and the cleaning unit 109. A drive mechanism 110 that contacts and separates the transfer roller 108 is rotatably supported by the rotation center shaft 111, the rotation center shaft 111 is rotatably supported, and the support portion 112 is driven by the drive roller 104. A spring 113 that urges toward the side, a cam 114 that swings the support portion 112, a cam shaft 115, and the like. Similarly, the drive mechanism 120 that contacts and separates the cleaning unit 109 is also supported by the rotation center shaft 121, the support unit 122 that is rotatably supported by the rotation center shaft 121, and the support unit 122. A spring 123 that biases the roller 105, a cam 124 that swings the support portion 122, a cam shaft 125, and the like are included.
JP-A-4-340564

  As described above, in the conventional color image forming apparatus 100, in order to apply tension to the intermediate transfer belt 103, the tension roller 106 is moved in a direction perpendicular to the surface of the intermediate transfer belt 103 stretched between the drive roller 104 and the idle roller 105. At this time, it is necessary to move the tension roller 106 so that the shaft of the tension roller 106 is parallel to the shafts of the driving roller 104 and the idle roller 105 so that the intermediate transfer belt 103 does not meander.

  However, since the tension roller 106 moves linearly in this way, it is necessary to provide a gap between the tension roller 106 and its support member (not shown), and thus parallel to the drive roller 104 and the idle roller 105. It is difficult to move while maintaining.

  Therefore, in the present invention, an image forming apparatus capable of accurately positioning the tension roller and preventing high-quality image formation by preventing meandering of an intermediate transfer body such as an intermediate transfer belt. The purpose is to provide.

  In order to solve the above-described problems, an image forming apparatus according to the present invention is wound around a roller group including a driving roller and a supporting roller rotatably supported on a fixed shaft, and a tension roller. The formed color toner images are sequentially transferred to form a composite toner image, and an intermediate transfer body for transferring the composite toner image to a transfer material and a tension roller are rotatably supported, and a predetermined axis And an arm that swings around the center.

  According to the present invention, since the tension roller is pivotally supported by the arm that swings about a predetermined axis, the swing center axis of the arm and the rotation center of the tension roller are controlled regardless of the position of the tension roller. The distance from the shaft can be kept constant, and the tension roller can be accurately positioned with reference to the swing center axis of the arm. Thereby, meandering of the intermediate transfer member can be prevented and high-quality image formation can be performed. Further, since the meandering of the intermediate transfer member is prevented, the life of the intermediate transfer member can be extended. Furthermore, since the tension roller can be supported and functioned with a simple structure, the cost can be reduced.

  In the first invention of the present application, each color toner image formed on a photoreceptor is wound around a roller group composed of a driving roller and a supporting roller rotatably supported on a fixed shaft, and a tension roller. An intermediate transfer member for sequentially transferring to form a composite toner image and transferring the composite toner image to a transfer material, and an arm that rotatably supports a tension roller and swings about a predetermined axis And an image forming apparatus. According to the present invention, since the tension roller is pivotally supported by the arm that swings about a predetermined axis, the swing center axis of the arm and the rotation center of the tension roller are controlled regardless of the position of the tension roller. The distance from the shaft can be kept constant, and the tension roller can be accurately positioned with reference to the swing center axis of the arm. Thereby, meandering of the intermediate transfer member can be prevented and high-quality image formation can be performed. Further, since the meandering of the intermediate transfer member is prevented, the life of the intermediate transfer member can be extended. Furthermore, since the tension roller can be supported and functioned with a simple structure, the cost can be reduced.

  The second invention of the present application is an image forming apparatus in which the arm swings around the axis of the support roller. According to the present invention, since the swing center axis of the arm and the axis of the support roller can be shared, the number of parts can be reduced and the cost can be reduced.

  A third invention of the present application is an image forming apparatus having a cleaning unit that is pivotally supported by an arm and removes residual toner on the intermediate transfer member by contacting a tension roller via the intermediate transfer member. Is. According to the present invention, since the relative position between the cleaning means and the tension roller does not change regardless of the position of the tension roller, the cleaning performance is maintained.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus having a screw member that collects residual toner removed by the cleaning unit by being supported coaxially with the shaft on which the cleaning unit is supported and rotating. According to the present invention, the remaining toner can be collected with a small number of parts by the screw member that rotates around the shaft that is shared with the shaft on which the cleaning means is supported, and the cost can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a partially cutaway perspective view showing a main part of a color image forming apparatus according to an embodiment of the present invention, FIG. 2 is a view taken along arrow A in FIG. 1, and FIG. FIG. 8B is a diagram illustrating a state in which the cleaning blade is in contact with each other.

  As shown in FIGS. 1 and 2, the color image forming apparatus according to the embodiment of the present invention sequentially transfers each color toner image formed on the photoreceptor 102 to form a composite toner image, and this composite toner image From an intermediate transfer belt 1 as an intermediate transfer body for transferring the toner onto a sheet S as a transfer material, a driving roller 2, a support roller (idle roller) 3 and a tension roller 4 around which the intermediate transfer belt 1 is wound. And a group of rollers configured. The configuration other than the portion shown in FIG. 1 is the same as that of the conventional color image forming apparatus shown in FIG. 3, and will not be described below.

  The drive roller 2 and the support roller 3 are rotatably supported by fixed shafts 5 and 6, respectively. A T-shaped arm 7 that rotatably supports the tension roller 4 is provided on the fixed shaft 6 of the support roller 3 so as to swing around the fixed shaft 6. The tension roller 4 rotates about the rotation shaft 8 with respect to the arm 7. The arm 7 is provided at both ends of the fixed shaft 6 and supports the rotating shaft 8 and a rotating shaft 12 described later at both ends.

  Further, a housing 10 that supports a cleaning blade 9 that removes residual toner on the intermediate transfer belt 1 by contacting the tension roller 4 via the intermediate transfer belt 1 is pivotally supported on the arm 7 so as to be swingable. Yes. The arm 7 also rotatably supports a rotating shaft 12 of a screw member 11 that collects residual toner removed by the cleaning blade 9. The housing 10 is supported coaxially with the rotating shaft 12 of the screw member 11 with respect to the arm 7.

  The screw member 11 is a member in which a belt-like plate is spirally provided around the rotary shaft 12, receives the remaining toner that is removed by the cleaning blade 9 and falls, and conveys it to the outer waste toner conveying belt 13. It is. In addition, the color image forming apparatus includes a waste toner container 14 that stores waste toner transported by the waste toner transport belt 13.

  In the color image forming apparatus having this configuration, the arm 7 is urged counterclockwise in FIG. 2 about the fixed shaft 6 in order to apply tension to the intermediate transfer belt 1. As a result, the tension roller 4 swings according to the degree of bending of the intermediate transfer belt 1. At this time, the tension roller 4 is pivotally supported by the arm 7 and swings around the fixed shaft 6 together with the arm 7. Therefore, regardless of the position, the fixed shaft 6 and the tension roller which are the swing central shaft of the arm 7 are supported. The distance between the rotation axis 8 and the rotation axis 8 is kept constant.

  Therefore, in this color image forming apparatus, it is possible to accurately position the tension roller 4 with reference to the fixed shaft 6 that is the swinging central axis of the arm 7, and it is wound around the tension roller 4 and the rotating shaft 8. Further, meandering of the intermediate transfer belt 1 is prevented. Therefore, this color image forming apparatus can form a high quality image. Further, since the meandering of the intermediate transfer belt 1 is prevented, the life of the intermediate transfer belt 1 is extended. Further, since the tension roller 4 is supported by the arm 7 having a simple structure, the cost can be easily reduced.

  In the color image forming apparatus according to the present embodiment, the cleaning blade 9 is pivotally supported by the arm 7 through the housing 10 so as to be swingable, and is brought into contact with the tension roller 4 through the intermediate transfer belt 1. Since the remaining toner on the transfer belt 1 is removed, the relative position between the cleaning blade 9 and the tension roller 4 does not change and does not depend on the position of the tension roller 4. It can be removed and the cleaning property is maintained.

  Further, in the color image forming apparatus according to the present embodiment, the residual toner is collected by the screw member 11 and is transported to the waste toner container 14 by the waste toner transport belt 13 and removed. Since the rotating shaft 12 of the screw member 11 is shared with the shaft on which the cleaning blade 9 is supported, the remaining toner can be collected with a small number of parts. Further, in the color image forming apparatus according to the present embodiment, the number of parts can be reduced because the swing center axis of the arm 7 and the axis of the support roller 3 are shared.

  In the present invention, a toner image is sequentially formed on a photosensitive member with toners of different colors, and each toner image is transferred onto an intermediate transfer member to form a composite toner image. The composite toner image is transferred from the intermediate transfer member. It is useful as an image forming apparatus that performs batch transfer onto a transfer material. In particular, the present invention is suitable as an image forming apparatus capable of accurately positioning a tension roller and capable of forming a high-quality image by preventing meandering of an intermediate transfer member.

1 is a partially cutaway perspective view showing a main part of a color image forming apparatus according to an embodiment of the present invention. (A) A view of FIG. 1 showing a state where the cleaning blade is separated, (b) A view of FIG. 1 showing a state where the cleaning blade is in contact Sectional view of a conventional 4-pass color image forming apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intermediate transfer belt 2 Drive roller 3 Support roller 4 Tension roller 5, 6 Fixed shaft 7 Arm 8, 12 Rotating shaft 9 Cleaning blade 10 Housing 11 Screw member 13 Waste toner transport belt 14 Waste toner container

Claims (4)

A combined toner image is formed by sequentially transferring each color toner image formed on a photoreceptor, wound around a roller group composed of a drive roller and a support roller rotatably supported on a fixed shaft, and a tension roller. An intermediate transfer member for forming and transferring the synthetic toner image to a transfer material;
An image forming apparatus comprising: an arm that pivotally supports the tension roller and swings about a predetermined axis. The image forming apparatus according to claim 1, wherein the arm swings about an axis of the support roller. 2. The cleaning device according to claim 1, further comprising a cleaning unit that is pivotally supported by the arm and removes residual toner on the intermediate transfer member by contacting the tension roller via the intermediate transfer member. The image forming apparatus according to 2. 4. The image forming apparatus according to claim 3, further comprising a screw member that is supported coaxially with a shaft on which the cleaning unit is supported and rotates to collect residual toner removed by the cleaning unit.

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