JPH0885644A - Image forming device - Google Patents

Abstract

(57) [Summary] [Object] To provide an image forming apparatus capable of easily avoiding back stain of a transfer material and obtaining a high-definition image while suppressing a complicated structure and an increase in cost. An image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, a developing unit that adheres toner to the electrostatic latent image surface to form a toner image, and the toner image. A plurality of image forming units having transfer means for transferring to a transfer material are continuously arranged, and the toner images formed for each image forming unit are sequentially transferred by the transfer means to the transfer material surface conveyed by the conveying means. In the image forming apparatus, the transporting means for transporting the transfer material is composed of a transfer material transport belt suspended by a positionally fixed driving roller and a driven roller, and the transfer material is transported to a flat portion other than the transfer area. It is characterized in that it is provided with a cleaning member for the transfer material conveying belt which also serves as an urging member for the transfer material conveying belt longer than the belt width, for example, a polyurethane resin plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
The present invention relates to an image forming apparatus such as a color copying machine including a plurality of image forming units that form images of different colors.

[0002]

2. Description of the Related Art In recent years, in response to the color orientation of offices,
Color printers and color copiers have appeared. One of the methods of these image forming apparatuses is an image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, and a toner image is formed by attaching toner to the electrostatic latent image surface. A so-called photosensitive drum four-series tandem system may be used, in which four image forming units each having a developing unit and a transfer unit that transfers the toner image to a transfer material are incorporated. This method is
Four photoconductor drums are arranged in parallel, and a toner image for each toner color is formed on each of the photoconductor drums using yellow, magenta, cyan, or black toner, and the toner images are aligned by a registration roller and transferred. In this method, each toner image is sequentially transferred onto one transfer material surface conveyed by a belt to obtain a color image.

By the way, an image forming apparatus having a plurality of image forming units incorporated therein is provided with a transfer material conveying belt as described above in order to convey a transfer material for sequentially transferring toner images in a layered manner. There is. That is, it can be said that an endless type transfer material conveying belt that is controlled so that the toner image can be transferred onto the transfer material surface by the transfer means in synchronization with the formation of the toner image in each image forming unit. An endless type transfer material conveying belt of this type is suspended between a positionally fixed driving roller and a driven roller and conveys the transfer material in a certain direction, while ensuring reliable transfer and the back surface of the transfer material. In consideration of prevention of contamination of the cleaning roller and the like, a cleaning roller is provided outside the drive roller in a region where the transfer material conveying belt moves in a flat surface.

However, the following problem arises in the structure in which the cleaning roller surface is rubbed against the transfer / transport belt surface at a flat portion other than the curved portion around which the transfer material transport belt is wound around the drive roller. . That is, even if the surface of the transfer material conveying belt is rubbed by the cleaning roller, there is a limit to the degree of cleaning. Especially, at the both ends in the width direction of the transfer material conveying belt, scattered or adhered toner or paper powder, etc. Stains cannot be sufficiently cleaned, and when the toner image is transferred, the transfer medium (paper) is soiled on the back side, and further, the suction mechanism is soiled, and the front side of the transfer medium is often soiled. . Further, in the case of the type in which the driven roller is fixed and the transfer material conveying belt is stretched (suspended) between the driving roller and the driven roller, a separate roller or the like is required as a biasing member.

[0005]

In the full-color image forming apparatus of various systems as well as the four-tandem tandem system, stains on the output transfer material (toner image transfer paper) are
It becomes an even bigger problem. That is, even in an image forming apparatus capable of high-definition printing without misalignment, for example, in order to save transfer material (transfer paper), back stains may occur when transferring and outputting a toner image on both surfaces of the transfer material. As a result, the front side becomes dirty, and as a result, the high-quality image forming function is lost. From this point of view, in transferring the toner image in the image forming apparatus, it is important to clean the transfer material conveying belt in order to prevent the occurrence of back stain on the transfer material.

From this point of view, conventionally, FIG.
The urging means and the cleaning means as shown in the different examples in (f) are adopted. That is, in the transfer material conveying system constituted by the transfer material conveying belt 3 suspended by the position-fixed driving roller 1 and driven roller 2, the biasing means 4 and the cleaning means 5 are provided separately or in the driven roller 2. It is known to have a dual-use configuration. 10A to 10C, the biasing means (biasing member) 4 and the cleaning means 5 are arranged along the transfer material conveying belt 3.
And the transfer material transport belt 3 is stretched, and the transfer material transport belt 3 is cleaned. In addition, in FIGS. 10D to 10F, while the cleaning means 5 is arranged along the transfer material conveying belt 3, the driven roller 2 also serves as the urging means 4, so that the transfer material conveying belt 3 is moved. While being stretched, the transfer material transport belt 3 is cleaned.

However, the above conventional method has the following problems. First, in the structure of the biasing means 4, for example, the combination of the roller and the spring, the number of parts is increased, the structure is complicated, and the cost is increased to adjust the transfer material conveying belt 3. . Secondly,
As shown schematically in FIGS. 11 (a) and 11 (b), since a cleaning blade 5 having a length shorter than the width of the transfer material conveying belt 3 is generally used, the cleaning blade 5 stretches the transfer material conveying belt 3. If an attempt is made to install the transfer material transport belt 3, both ends are pressed and bent by the tension of the transfer material transport belt 3 and a uniform load cannot be applied to the transfer material transport belt 3. Had poor cleaning. For this reason, the toner remains on the transfer material transport belt 3 and stains the back of the paper during the next printing. Figure 11
In FIG. 11B, the cleaning blade 5 is in the cleaning possible state when the edge of the cleaning blade 5 comes into contact with the transfer material conveying belt 3 by the MM line, but in FIG. 11B, the cleaning blade 5 is attached to the transfer material conveying belt 3 by the NN line. Indicates a poor cleaning condition.

The present invention has been made in consideration of such circumstances, and it is possible to easily avoid back stain on the transfer material and obtain a high-definition image while suppressing the complexity of the structure and the cost increase. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0009]

A first image forming apparatus according to the present invention comprises an image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the image carrier, and the electrostatic latent image surface. A plurality of image forming units, each having a developing unit for forming a toner image by adhering toner to the sheet and a transfer unit for transferring the toner image onto a transfer material, are continuously arranged, and a toner image formed for each image forming unit. An image forming apparatus for sequentially transferring the transfer material onto the surface of the transfer material that is transferred by the transfer means, wherein the transfer means that transfers the transfer material is suspended by a position-fixed driving roller and a driven roller. A cleaning member for a transfer material conveying belt, which is composed of a material conveying belt and also serves as an urging member for the transfer material conveying belt longer than the width of the transfer conveying belt, on a flat portion other than the transfer area, for example, a polyurethane resin. Characterized in that it comprises a manufacturing plate.

A second image forming apparatus according to the present invention comprises an image bearing member, an electrostatic latent image forming means for forming an electrostatic latent image on the image bearing member, and toner attached to the electrostatic latent image surface. A plurality of image forming units each having a developing unit for forming a toner image and a transfer unit for transferring the toner image onto a transfer material are continuously arranged, and the toner image formed for each of the image forming units is conveyed by the conveying unit. In the image forming apparatus for sequentially transferring to the incoming transfer material surface by the transfer means, the transfer means for transferring the transfer material includes a transfer material transfer belt suspended by a positionally fixed driving roller and a driven roller, In addition, a cleaning member for a transfer material conveying belt is provided in a flat portion other than the transfer area, the central portion of which also functions as a biasing member for the transfer material conveying belt is concaved in an arc shape.

Here, the length of the cleaning member is generally H≤L≤W, where L is L, width of the toner image (printing area) to be transferred is H, and transfer conveyance belt width is W. Shown in a relationship. The length of the cleaning member is preferably longer than the width of the transfer material conveying belt.

A third image forming apparatus according to the present invention comprises an image bearing member, an electrostatic latent image forming means for forming an electrostatic latent image on the image bearing member, and toner attached to the electrostatic latent image surface. A plurality of image forming units each having a developing unit for forming a toner image and a transfer unit for transferring the toner image onto a transfer material are continuously arranged, and the toner image formed for each of the image forming units is conveyed by the conveying unit. In the image forming apparatus for sequentially transferring to the incoming transfer material surface by the transfer means, the transfer means for transferring the transfer material includes a transfer material transfer belt suspended by a positionally fixed driving roller and a driven roller, Further, a cleaning member for the transfer material conveying belt, which also functions as an urging member for the transfer material conveying belt, is disposed in a flat portion other than the transfer area and is obliquely arranged with respect to the traveling direction of the transfer conveying belt. And butterflies.

In this structure, the length of the cleaning member (cleaning means) does not necessarily have to be longer than the width of the transfer / transport belt, but it is more effective to set it to be longer than the width of the transfer / transport belt.

[0014]

According to the image forming apparatus having the above-mentioned structure, the transfer material conveying belt can easily secure a required tension state, while the toner and paper dust on the transfer material conveying belt can be easily and surely cleaned and removed. To be done. Therefore, the transfer material (output paper) carried by the transfer material carrying belt is carried in a uniform flat surface over the entire surface, and back stains are eliminated.
It is possible to obtain a high-quality output image. Moreover, this image forming apparatus is economical because the configuration and operation are simple and the cost is suppressed or reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

First, the structure of a color copying machine as an image forming apparatus will be schematically described with reference to FIGS. 1 and 2.

FIG. 1 shows the overall construction of the apparatus, and FIG. 2 shows a transfer material conveying belt portion which constitutes a main part. Inside the main unit A, yellow (Y), magenta (M), cyan (C), black (BK)
Image forming units 7Y, 7M, 7C, which form the toner images of
7BK is mounted and arranged in a certain direction. The image forming unit 7Y includes a photosensitive drum 8Y as an image carrier, an electrostatic latent image forming means (exposure means, etc.) 9Y for forming an electrostatic latent image on the image carrier 8Y, and the electrostatic latent image surface. A developing means 10Y for forming a toner image by adhering toner to the toner and a transfer means 11Y for transferring the toner image onto a transfer material are employed. 12Y is a cleaning device for the image carrier 8Y, 1
3Y is a charge removing device for the image bearing member 8Y, and 14Y is a charging device for the image bearing member 8Y, which is a part of the electrostatic latent image forming means 9Y. Since the image forming units 7M, 7C, 7BK also have the same configuration as that of the image forming unit 7Y, the same portions are denoted by the same reference numerals and the same color, and detailed description thereof will be omitted.

Below the image forming units 7Y, 7M, 7C and 7BK which are continuously arranged, a transfer conveyer belt 15 as a transfer material conveyer is stretched, and the photosensitive drum 8Y, The transfer material 16 such as paper is intermittently conveyed to 8M, 8C, and 8BK. Further, transfer devices 11Y, 1Y serving as transfer means sandwiching the transfer material conveying belt 15 are provided at positions facing the photoconductor drums 8Y, 8M, 8C, 8BK.
1M, 11C, 11BK are arranged, and the photoconductor drums 8Y, 8
The toner images of the corresponding colors formed on M, 8C, and 8BK are transferred onto the surface of the transfer material 16 conveyed by the transfer material conveying belt 15. The transfer material 16 is a paper feed system.
By means of 17, the sheet is supplied onto the transfer material conveying belt 15 at a proper timing.

Here, the paper feed system 17 is, as shown in FIG.
A pickup roller 19 that takes out the transfer material 16 from the paper feed cassette 18, a feed roller pair 20 that conveys the transfer material 16 that is taken out by the pickup roller 19, and a tip alignment of the transfer material 16 that is conveyed by the feed roller pair 20. Registration roller pair 21
Etc. The pair of registration rollers 21
The transfer speed of the transfer material 16 by the transfer material transport belt 15 is set to be equal to the peripheral speed of the photoconductor drums 8Y, 8M, 8C and 8BK.

Further, the transfer material 16 by the transfer material conveying belt 15
The fixing device 22, the pair of paper discharge rollers 23, and the paper discharge tray 24 are sequentially provided in the conveyance direction (left direction in the drawing) of the image forming units 7Y, 7M, 7C, and 7BK,
Control unit that controls the operation of the paper feed system 17 and other devices
25 are installed.

When color image formation is designated from the operation input unit (not shown), yellow (Y), magenta
The image forming units 7Y, 7M, 7C and 7BK corresponding to (M), cyan (C) and black (BK) are on the surfaces of the photoconductor drums 8Y, 8M, 8C and 8BK operating at a predetermined timing. The toner images of the colors corresponding to are formed. For example, regarding the image forming unit 7Y, the photoconductor drum 8Y rotates in the clockwise direction (the direction of arrow A) in the figure and the charging device
It is uniformly charged by 8Y. Next, an exposure operation is performed by the exposure device 9Y on the uniformly charged surface of the photoconductor drum 8Y to form a latent image corresponding to a yellow image. By facing the developing device 10Y, this latent image is developed and a yellow toner image is formed on the surface of the photoconductor drum 8Y. Note that toner images of corresponding colors are similarly formed in the image forming units 7M, 7C, 7BK of other colors.

On the other hand, in synchronism with the toner image forming operation, the transfer material 16 is taken out from the paper feed cassette 18 and the front end of the transfer material 16 is aligned by a pair of registration rollers 21. Sent to. Transfer material conveyor belt 15
The transfer material 16 sent to the upper side is conveyed along with the traveling of the transfer material conveying belt 15 in a state of being electrostatically adsorbed to the transfer material conveying belt 15 by the suction roller 26, and first, the yellow toner image transfer position, that is, , Photoconductor drum 8Y and transfer device 11Y
Are sent to opposite positions with the transfer material transport belt 15 interposed therebetween. Then, at this yellow toner image transfer position, the transfer material 16 comes into contact with the yellow toner image on the photoconductor drum 8Y, and the yellow toner image on the photoconductor drum 8Y is transferred by the transfer device 11Y. Transcribed on 16. That is, the transfer device 11Y is composed of a transfer roller having semiconductivity, and has a polarity opposite to the potential of the yellow toner image electrostatically attached to the photoconductor drum 8Y from the back side of the transfer material transport belt 15. Supply an electric field having. This electric field is generated by the transfer material conveying belt 15 and the transfer material 16
Acts on the yellow toner image on the photoconductor drum 8Y through the through, and as a result, the yellow toner image is transferred from the photoconductor drum 8Y to the transfer material 16.

The transfer material 16 on which the yellow toner image has been transferred in this manner is then transferred to the magenta image forming unit 7M,
Cyan image forming unit 7C, black image forming unit
The toner image is sequentially transferred to the 7BK toner image transfer position, and the magenta toner image, the cyan toner image, and the black toner image are sequentially transferred to form a color image. The transfer material 16 on which the color toner image is formed is separated from the transfer material conveying belt 15 and sent to the fixing device 22, and after the color toner images with color superposition are permanently fixed, the transfer roller pair 23 is removed. It is carried out to the paper discharge tray 24 via. On the other hand, the transfer material transport belt 15 from which the transfer material has been peeled off is driven to rotate as it is, and the belt cleaning means 27 cleans the residual toner and paper dust,
Next, the surface potential is made constant by the discharging roller 28 for the transfer material transport belt.

Further, the photosensitive drums 8Y, 8M, 8C and 8BK after the toner image is transferred are rotationally driven as they are, and residual toner and paper dust are cleaned by the cleaning devices 12Y, 12M, 12C and 12BK. Next, the static eliminator 13Y,
13M, 13C, 13BK static elimination lamps keep the surface potential constant, and if necessary, charge device 14Y, 14M, 14C, 14BK again.
It will enter a series of processes from.

In the image forming apparatus having the image forming function as described above, in the present invention, the transfer material conveying belt 3 suspended between the driving roller 1 and the driven roller 2 which are fixed in position.
By also installing the cleaning blade 5a longer than the width of the transfer material conveying belt, also as the tensioning urging member,
Insufficient cleaning, complicated structure, etc., which have been regarded as problems in the past, are solved.

First, in the transfer material conveying system of the image forming apparatus according to the first aspect of the present invention, as shown in FIGS. 3 (a) and 3 (b), the cleaning blade 5a is attached and arranged. That is, by eliminating the tensioning mechanism that has been conventionally performed by using a roller or the like and pushing the edge of the cleaning blade 5a for tensioning, the configuration can be simplified and the cost can be reduced. Here, by setting the length of the cleaning blade 5a longer than the width of the transfer material conveying belt 15, a uniform load is applied to the transfer material conveying belt 15. More specifically, as shown in FIG. 11 (b), in the conventional method, both ends of the cleaning blade 5 are most deformed by the load received from the transfer material conveying belt 3, and the cleaning blade 5 does not hit the abdomen. This is because the toner and paper dust on the transfer material transport belt 3 are not scraped off cleanly and the transfer material (printing paper) is soiled. On the contrary, the cleaning blade 5 does not evenly apply the load to the transfer material transport belt 3 and adversely affects the running of the transfer material transport belt 3, for example, meandering, and affects the formed image.

Here, by using the cleaning blade 5a longer than the width of the transfer material conveying belt 3 so that the end of the cleaning blade 5a does not abut against the inside of the width of the transfer material conveying belt 3, the cleaning blade 5a shown in FIG. As shown in the side view, the transfer material conveying belt 15 and the cleaning blade 5a maintain a uniform contact state. That is, the cleaning blade 5a serves as an urging member for stretching the transfer material transport belt 15, and there is no factor that adversely affects the running of the transfer material transport belt 15. In addition, the transfer material transport belt 15
The edge of the cleaning blade 5a also scrapes off foreign matter such as toner adhering to the top of the cleaning blade 5a for cleaning. Further, even if the cleaning blade 5a of the present invention is installed so that the contact direction of the cleaning blade 5a is opposite to the traveling direction of the transfer material conveying belt 16 as shown in FIG. 3 (a), as shown in FIG. The same effect was confirmed in both cases, even if they were attached in a direction that was in conformity with the traveling direction. Next, in the image forming apparatus according to the second aspect of the invention, the cleaning blade having the structure illustrated in FIG.
5b is installed and placed. That is, as shown in FIG. 5, by adopting a configuration in which the cleaning blade 5b having a circular shape in which both ends of the ridge line portion are high and the central portion is low in plan view is installed along the transfer material transport belt 15. The uniform tension is secured over the entire width of the transfer material transport belt 15 while sufficient cleaning is possible.

More specifically, in this respect, as described above, in the conventional plate-shaped cleaning blade 5b,
Both ends thereof are deformed by the force received from the transfer material conveying belt 3 (the force of the blade pushing the belt), and the cleaning failure is caused. It has the required strength so that it will not occur. However, at this time, the cleaning blade needs to have a length that satisfies the relationship of H ≦ L ≦ W. Here, H is an image print area, or an area such as the width of the developing device where toner may be attached to the belt, L is the length of the cleaning blade, and W is the width of the transfer material conveying belt. 6A is a perspective view showing a state in which the arc portion 5b 'of the cleaning blade 5b is pressed against the transfer material conveying belt 15 in the image forming apparatus according to the present invention.
(b) is a cross-sectional view schematically showing an aspect in which the arcuate portion 5b 'side of the cleaning blade 5b is in contact with the transfer material conveying belt 15 at the aa line and the bb line at that time. Here, since the strength of both ends of the cleaning blade 5b is increased, the transfer material conveying belt 15 is applied with a uniform load, and the cleaning blade 5b serves as a biasing member for tensioning the transfer material conveying belt 15. It will be. However, the main purpose of the cleaning blade 5b is to clean the transfer material transport belt 15, and therefore, this point will be explained. For example, in the experiment of the transfer material transport belt cleaning characteristic of the present inventor, the cleaning blade was used for the transfer material transport belt 15.
The result that good cleaning is possible was obtained by setting the bite amount of 5b to about 0.5 mm to 2 mm (however, the rubber hardness is JIS-A Hs65 ° urethane rubber cleaning Kinkink blade 5b, Transfer material conveyor belt 15
The mounting angle was 15 degrees). That is, FIG.
The relation between the height H ₂ of the blade end and the height H _{1 of the} central portion shown in is 0 ≦ H ₂ −H ₁ ≦ 1.5 mm (however, the biting amount in the central portion H ₁ is 0.5 to 2 mm). If so, the cleaning blade functions as a biasing member for the transfer material transport belt 15, and the biasing member can be omitted, and the number of parts and cost can be reduced accordingly. Further, in the cleaning blade 5b, as shown in a perspective view in FIG. 7, for example, even if the cleaning blade 5b is mounted so as to oppose the traveling direction of the transfer material transport belt 15, the cleaning blade 5b is mounted in the same order as in the case of FIG. The effects of the above invention can be obtained.

Further, in the transfer material conveying system of the image forming apparatus according to the third aspect of the present invention, as illustrated in FIG. 8, the cleaning blade 5c is arranged with respect to the running direction of the transfer material conveying belt 15.
It is installed and arranged in a diagonal pattern. That is, by mounting the flat plate-shaped cleaning blade 5c obliquely with respect to the traveling direction of the transfer material transport belt 15, while cleaning and stretching the transfer material transport belt 15,
The meandering of the transfer material transport belt 15 which has been a problem in the past is suppressed.

In the configuration example shown in a perspective view in FIG. 8, the front side is inclined with respect to the driving roller 1 and the rear side is inclined with respect to the driven roller 2 side. Here, if the length of the cleaning blade 5c is set in such a manner that the cleaning blade 5c is obliquely arranged, and both ends are projected from the width of the transfer material transport belt 15, a more sufficient cleaning action and biasing action can be obtained. can get. Further, as shown in a perspective view in FIG. 9, as the cleaning blade 5c is obliquely attached to and arranged on the transfer material conveying belt 15, a force for advancing in a direction orthogonal (vertical) to the cleaning blade 5c. Fx is generated on the transfer material transport belt 15. Then, when this force Fx is decomposed into a force in the conveying direction of the transfer material conveying belt 15 and a force in a direction perpendicular thereto, a force Fh in the conveying direction of the transfer material conveying belt 15 and a force Fv in the perpendicular direction are obtained. That is, this Fv suppresses the meandering of the transfer material conveying belt 15 and causes the transfer material conveying belt 15 to move toward one side. In other words, in the conventional configuration, the driven roller 2 has a tapered (conical) shape to suppress the meandering of the transfer material conveying belt 15 to obtain a high-quality image, but in the present invention, the cleaning blade 5c is used. If the side surface of the transfer material transport belt 15 is slid by using a frame or block (not shown) that is mounted diagonally and supports the driving roller 1 and the driven roller 2 of the transfer material transport belt 15, the transfer is performed. The meandering of the material conveying belt 15 is prevented, and the material travels a certain amount. Then, the driven roller 2 is tapered (conical).
For a significant increase in cost due to the shape,
In the case of the present invention, the same function is easily obtained at a low cost. Further, also in the case of the image forming apparatus according to this embodiment, the same function can be obtained whether the mounting direction of the cleaning blade with respect to the transfer material transport belt 15 is opposite to the running direction of the transfer material transport belt or in the following direction. .

It should be noted that the present invention is not limited to the above-exemplified configuration, and various modifications can be made without departing from the spirit of the present invention. For example, a combination type may be adopted in which the driven roller functions as an urging member in addition to the cleaning blade for the transfer material conveying belt stretched between the position-fixed driving roller and the driven roller.

[0032]

As described above, according to the present invention,
In a multicolor color image forming apparatus that uses a transfer belt suspended on a fixed drive and driven roller, a cleaning member that also has a function of stretching the transfer material transport belt is installed to extend the transfer material transport belt. It is possible to perform good cleaning and form a high-quality image while reducing the number of parts, simplifying the configuration, and reducing the cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing the outline of the configuration of an image forming apparatus that is a first embodiment according to the present invention.

FIG. 2 is a sectional view showing a part of FIG. 1 in an enlarged manner.

3A and 3B show an installation state of a cleaning member having a belt tensioning function on a transfer material conveying belt in the image forming apparatus shown in FIG. 1, (a) is a perspective view, and (b) is a side view.

FIG. 4 is a perspective view showing another installation state of the cleaning member that also has a belt tensioning function on the transfer material transport belt in the image forming apparatus shown in FIG.

FIG. 5 is a plan view showing another configuration example of a cleaning member which also has a belt tensioning function on the transfer material transport belt arranged in the image forming apparatus shown in FIG.

6A and 6B show a state in which the cleaning member shown in FIG. 5 is installed on a transfer material conveyance belt. FIG. 6A is a perspective view and FIG.
Side view.

FIG. 7 is a perspective view showing another installation state of the cleaning member shown in FIG. 5 with respect to the transfer material transport belt.

8 is a perspective view showing a state in which a cleaning member also having a belt tensioning function is installed on the transfer material transport belt in the image forming apparatus shown in FIG.

FIG. 9 is a schematic diagram showing directions of forces applied to a cleaning member due to a transfer operation of a transfer material transfer belt in the state shown in FIG.

10 (a), (b), (c), (d), (e), and (f) respectively show a belt tensioning means and a cleaning member on a transfer material conveying belt in a conventional image forming apparatus. The side view which shows each different installation state.

FIG. 11 is a cross-sectional view showing a state where a cleaning member is installed on the transfer material transport belt in the conventional image forming apparatus.

[Explanation of symbols]

1 …… Drive roller 2 …… Driven roller 3,15 ……
Transfer material conveying belt 4 ...... biasing member (means) 5, 5a, 5b, 5c …… cleaning member (means) 6 …… image forming apparatus main body 7Y, 7M, 7C, 7BK …… image forming unit 8Y, 8M, 8C, 8BK ... Image carrier (photosensitive drum) 9Y, 9M, 9C, 9BK ... Electrostatic latent image forming means
10Y, 10M, 10C, 10BK ... Developing means 11Y, 1
1M, 11C, 11BK …… Transfer means (transfer device) 12Y, 1
2M, 12C, 12BK ... Image carrier cleaning device 13
Y, 13M, 13C, 13BK ... Static eliminator 14Y, 14M, 14
C, 14BK …… Charging device 16 …… Transfer material (recording paper) 1
7 ... Paper feed system 18 ... Paper feed cassette 19 ... Pickup roller 20 ... Feed roller 21 ... Registration roller pair 22 ... Fixing device 23 ... Paper ejection roller
24 …… Paper ejection tray 25 …… Control unit 26 …… Adsorption roller 27 …… Transfer material transport belt cleaning means 28 …… Transfer material transport belt neutralization roller 35 ………… Biasing member 40 for tensioning the transfer belt 40 …… …
... Control unit

Claims (3)

[Claims] 1. An image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, a developing unit that adheres toner to the electrostatic latent image surface to form a toner image, and the toner. A plurality of image forming units having transfer means for transferring an image to a transfer material are continuously arranged, and the toner image formed for each of the image forming units is transferred by the transfer means to the transfer material surface conveyed by the transfer means. An image forming apparatus for sequentially transferring, wherein a conveying unit that conveys the transfer material includes a transfer material conveying belt that is suspended by a position-fixed driving roller and a driven roller, and a flat portion other than the transfer area, An image forming apparatus comprising: a cleaning member for a transfer material conveying belt, which also functions as an urging member for the transfer material conveying belt longer than the width of the transfer conveying belt. 2. An image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the image carrier, a developing unit for adhering toner to the electrostatic latent image surface to form a toner image, and the toner. A plurality of image forming units having transfer means for transferring an image to a transfer material are continuously arranged, and the toner image formed for each of the image forming units is transferred by the transfer means to the transfer material surface conveyed by the transfer means. An image forming apparatus for sequentially transferring, wherein a transporting device for transporting the transfer material is composed of a transfer material transport belt suspended by a positionally fixed driving roller and a driven roller, and on a flat portion other than the transfer area, An image forming apparatus comprising: a cleaning member for a transfer material conveying belt, the central portion of which doubles as a biasing member for the transfer material conveying belt, and which has a concave arc shape. 3. An image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the image carrier, a developing unit for forming a toner image by adhering toner to the electrostatic latent image surface, and the toner. A plurality of image forming units having transfer means for transferring an image to a transfer material are continuously arranged, and the toner image formed for each of the image forming units is transferred by the transfer means to the transfer material surface conveyed by the transfer means. An image forming apparatus for sequentially transferring, wherein a transporting device for transporting the transfer material is composed of a transfer material transport belt suspended by a positionally fixed driving roller and a driven roller, and on a flat portion other than the transfer area, An image forming apparatus comprising: a cleaning member for a transfer material conveying belt, which also functions as an urging member for the transfer material conveying belt, which is obliquely crossed with respect to the traveling direction of the transfer conveying belt.