JP2006098583A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary transfer device, capable of removing paper powder on a secondary transfer object, before the paper powder reaches a cleaning member and preventing nonconformities caused by the insertion of the paper powder into the cleaning member. <P>SOLUTION: In this image forming apparatus, a paper powder removing brush roller 70 contacts a secondary transfer roller on the upstream of a cleaning blade 71 by a penetrating amount (a), and insertion of the paper powder in the blade 71 is prevented. The image forming apparatus is constituted so that the paper powder brush roller 70 is installed at a position (only at the center part), corresponding to a position of a paper feed roller 50, and the paper powder removing brush roller 70 becomes slightly longer, as shown in Fig. 3. Thus, rotation torque of the brush roller becomes a quarter or smaller, load torque of a driving motor is reduced, and thereby power saving is attained. In addition, further paper powder removal effect and toner removal effect are obtained, by constituting the image forming apparatus to apply bias to the brush roller 70. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to cleaning of a secondary transfer member.

Conventionally, it has been described that paper dust can be removed by installing a brush member upstream of the cleaning blade in the cleaning blade. However, in the present invention, the effect of removing paper dust can be obtained with low torque. Power saving can also be obtained.
By making the amount of biting into the transfer member of the brush member 1 mm or more, a further paper dust removing effect can be obtained.

Since the secondary transfer member is in contact with the intermediate transfer member, the background stain toner and the process pattern on the intermediate transfer member are transferred between the portions where the transfer material such as transfer paper is not placed or between the papers. Dirty body. For this reason, the secondary transfer roller is provided with a cleaning blade for cleaning the toner, and the cleaning blade is pressed against the surface of the transfer roller to scrape off the toner. As described above, the toner is usually removed by the blade, and no trouble occurs in the transfer and separation processes.

However, as a defect in the cleaning blade, a toner cleaning failure due to paper dust swallowing into the blade is raised. Conventionally, the sheets are loaded in a sheet feeding cassette and are sent out one by one by a sheet feeding roller. At that time, the sheets are rubbed, the sheets are crumpled, and paper dust is generated. This flaking or generated paper dust adheres to a paper transport roller provided in the paper transport path, a transfer roller as a transfer means, or an intermediate transfer member. In particular, a large amount of paper dust is generated in the portion corresponding to the paper feed roller position as compared with other portions.
In addition, since there are many types of transfer paper and recycled paper has increased recently, paper with a large amount of paper dust is also on the market. The paper dust remains on the transfer roller and should be scraped off by the blade in the same manner as the toner. However, since it is fibrous, it is trapped between the transfer belt and the blade. The collected paper dust creates a gap between the transfer roller and the blade and causes the toner to slip through. In addition, there is a situation in which the toner is stopped when the paper dust is collected and cleaning is not performed.

In such a state, first, since toner remains on the transfer belt, the toner is transferred to the back of the transfer paper in the next transfer process, causing back stain. Second, since the toner remains on the secondary transfer body, the toner is interposed between the secondary transfer body and the transfer paper, so that the adsorbing force between the two is reduced and the transfer paper from the intermediate transfer body is transferred. Cause poor separation. Further, when the state where the paper dust is stagnated continues, the transfer roller is rubbed with toner, and the toner adheres to the transfer roller and causes filming. In this state, the toner cannot be cleaned even if the paper dust is removed, resulting in backside dirt and poor separation, and the transfer roller must be replaced, which is wasted.

In addition, as described in Patent Document 1, as a method for removing paper dust, there is a method in which the transfer roller is reversed at regular intervals and the paper dust is shifted and dropped (removal of paper dust by reverse rotation). In the case of a machine, there is no time for reversing operation during continuous copying, and paper dust accumulates. Also, continuous copying raises the temperature in the machine and easily causes toner filming.
JP-A-10-333455

The present invention has been made in view of the above circumstances, and is generated by removing paper dust before the paper dust on the secondary transfer body reaches the cleaning member and swallowing the paper dust into the cleaning member. It is an object of the present invention to provide a secondary transfer apparatus that can prevent such a problem.

As means for solving the above problems, the present invention has the following features.
In the image forming apparatus according to claim 1, an endless intermediate transfer belt that is stretched and rotated by several rollers, and an image forming unit and a secondary transfer member disposed along the intermediate transfer belt are provided. An image forming apparatus for transferring a toner image formed on an image carrier of the image forming unit to an intermediate transfer belt, transferring the toner image onto a transfer material on a secondary transfer body, and transporting the transferred toner image. In the image forming apparatus, the secondary transfer member has a cleaning unit, and the cleaning unit is a rubber blade that is always in contact with the secondary transfer member. The image forming apparatus rotates on the upstream side of the cleaning unit in the rotation direction of the secondary transfer member. A possible roller-shaped brush member is provided, and the brush member is attached only to the position of the paper feeding and conveying roller.

According to a second aspect of the present invention, the amount of biting of the brush member with respect to the secondary transfer member is 1 mm or more.
The image forming apparatus according to a third aspect is further characterized in that a flicker member is brought into contact with the brush member.
According to a fourth aspect of the present invention, the material of the brush member is a polyester resin.
The image forming apparatus according to claim 5 is further characterized in that a bias is applied to the brush member.

As described above, in the image forming apparatus of the present invention, the brush member is rotated at a low torque by attaching the brush member only to the sheet feeding / conveying roller position to the secondary transfer member by the means for solving the above. In addition, it is possible to efficiently remove the paper dust generated in the paper feed roller. This is a problem that occurs when paper dust is squeezed into the cleaning blade, which has been a problem with conventional devices (toner filming). Generation, transfer paper back stains and separation failures, secondary transfer body life reduction, and the like.

In the image forming apparatus of the present invention, the effect of removing paper dust can be extended by setting the amount of biting of the brush member to the secondary transfer body to 1 mm or more.
Further, in the image forming apparatus of the present invention, when the paper dust removed from the transfer roller by the brush member accumulates on the brush member, it returns to the secondary transfer member and is sandwiched between the cleaning blades as in the case where there is no brush member. However, by bringing the flicker member into contact with the brush member, the paper dust on the brush member scraped off from the transfer member can be removed.
In the image forming apparatus of the present invention, the amount of change in the outer diameter of the brush member over time can be reduced by using a polyester resin as the material of the brush member. (Conventional acrylic resin was used as a brush member in the machine, but the outer diameter of the brush becomes smaller over time. Therefore, the amount of biting into the contacted object of the brush is reduced, and the paper dust removal effect is reduced. Paper dust is sandwiched between the two)
In the image forming apparatus of the present invention, paper dust can be attracted mechanically and electrostatically, and the effect of collecting paper dust can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a tandem indirect transfer type electrophotographic apparatus according to an embodiment of the present invention. In the figure, reference numeral 100 is a copying apparatus main body, 200 is a paper feed table on which the copying apparatus main body 100 is placed, 300 is a scanner mounted on the copying apparatus main body 100, and 400 is an automatic document feeder mounted on the scanner 300. (ADF).
The copying machine main body 100 is provided with an endless belt-like intermediate transfer member 10 at the center. The intermediate transfer member 10 is wound around three support rollers 14, 15, 16 and can be rotated and conveyed clockwise in the figure.

In the present embodiment, of the three rollers 14, 15, and 16, an intermediate transfer body cleaning device (cleaning means) that removes residual toner remaining on the intermediate transfer body 10 after image transfer is provided on the left side of the roller 16 in the drawing. ) 17 is provided. Further, four image formations of black, yellow, magenta, and cyan are formed on the intermediate transfer member 10 stretched between the first support roller 14 and the second support roller 15 along the conveyance direction. Means 18 are arranged side by side, and these image forming means (image forming units) 18 constitute a tandem image forming apparatus 20. An exposure device 21 is further provided on the tandem image forming apparatus 20.

On the other hand, a secondary transfer device (secondary transfer unit) 22 is provided on the side opposite to the tandem image forming apparatus 20 with the intermediate transfer body 10 interposed therebetween. The secondary transfer device 22 is configured by spanning a secondary transfer belt 24, which is an endless belt, between two rollers 23, and is pressed against the third support roller 16 via the intermediate transfer body 10. The image on the intermediate transfer body 10 is transferred to a sheet. A fixing device 25 for fixing the transferred image on the sheet is provided beside the secondary transfer device 22. The fixing device 25 is configured by pressing a pressure roller 27 against a fixing belt 26 that is an endless belt.

The secondary transfer device 22 described above also has a sheet transport function for transporting the image-transferred sheet to the fixing device 25. Of course, a transfer roller may be disposed as the secondary transfer device 22. However, in that case, it is difficult to provide this sheet conveying function together.
In the present embodiment, sheet inversion is performed below the secondary transfer device 22 and the fixing device 25 to invert the sheet so as to record images on both sides of the sheet in parallel with the tandem image forming apparatus 20 described above. A device 28 is provided.

Next, image formation by the color electrophotographic apparatus having the above configuration will be described. When making a copy using the color electrophotographic apparatus having the above-described configuration, first, a document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it.
Next, when a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is conveyed by the automatic document feeder 400 and moved onto the contact glass 32, and then the scanner 300 is driven. The first traveling body 33 and the second traveling body 34 travel. On the other hand, when the document is set on the contact glass 32, the scanner 300 is immediately driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34. The reflected light is further reflected by the mirror of the second traveling body 34 and enters the reading sensor 36 through the imaging lens 35. Thereby, the content of the original is read.

When the start switch is pressed as described above, one of the support rollers 14, 15, and 16 is rotationally driven by a drive motor (not shown), and the other two support rollers are driven to rotate, so that the intermediate transfer member 10 is rotated. It is rotated and conveyed. At the same time, the photoreceptor (image carrier) 40 is rotated by the individual image forming means 18, and black, yellow, magenta, and cyan monochrome images are formed on the photoreceptors 40. Then, along with the conveyance of the intermediate transfer member 10, these single color images are sequentially transferred to the intermediate transfer member 10, and a composite color image is formed on the intermediate transfer member 10.

Further, when the start switch is pressed as described above, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and a sheet is fed from one of the paper feed cassettes 44 provided in the paper bank 43 in multiple stages. It is paid out. (A rubber material or the like having a high frictional resistance is used because the paper supply roller needs to generate a sufficient frictional resistance with the paper surface when transporting the paper.) At that time, the paper supply roller 42 and the paper Rubs and the paper becomes garbled or paper dust is generated. The paper is separated one by one by the paper dust separation roller 45 generated by the flaking and introduced into the paper feed path 46, conveyed by the conveyance roller 47, and guided to the paper feed path 48 in the copying machine main body 100. The roller is abutted against the registration roller 49 and stopped. (The sheet feeding roller 42 is often installed at the center in the sheet conveying direction, and is also installed at the center in this embodiment.) When the manual feed tray 51 is used, the sheet feeding roller 50 is rotated, The sheets on the manual feed tray 51 are fed out, and the fed-out sheets are separated one by one by the separation roller 52 and then introduced into the manual feed path 53 and similarly abutted against the registration roller 49 and stopped. It is done.

Thereafter, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer member 10, and the sheet is fed between the intermediate transfer member 10 and the secondary transfer device 22. A color image is recorded on the sheet by the transfer by the secondary transfer device 22.
The sheet after the image transfer is conveyed by the secondary transfer device 22 and sent to the fixing device 25. After the transfer image is fixed by applying heat and pressure by the fixing device 25, the switching claw 55 is switched. The paper is discharged by a discharge roller 56 and stacked on a paper discharge tray 57. On the other hand, in the case of double-sided copying, a sheet with an image transferred on one side is introduced into the sheet reversing device 28 by the switching of the switching claw 55 and reversed, and then guided again to the transfer position, and the image is recorded on the back side. Thereafter, the paper is discharged onto a paper discharge tray 57 by a discharge roller 56.

On the other hand, the intermediate transfer body 10 after the image transfer is prepared by the intermediate transfer body cleaning device 17 to remove the residual toner remaining on the intermediate transfer body 10 after the image transfer, so that the tandem image forming apparatus 20 can prepare the image again.
In addition, since the secondary transfer device 22 is in contact with the intermediate transfer member, the background stain toner and the process pattern on the intermediate transfer member are transferred between the portions where the transfer material such as transfer paper is not placed or between the sheets. Since the secondary transfer belt 24 is soiled, the toner on the secondary transfer belt 24 is removed by the secondary transfer cleaning blade 71.

Further, upstream of the secondary transfer cleaning blade 71, there is provided a paper dust removing brush roller 70 that rotates only at a location that coincides with the position of the paper feed roller (in this embodiment, the central portion). The paper dust generated when the paper is fed is prevented from being caught in the secondary transfer cleaning blade 71. Further, the flicker member 72 is in contact with the paper dust removing brush roller 70, and the paper dust scraped by the brush roller 70 is removed from the brush roller 70. (Since the paper dust removal brush is in contact with the secondary transfer belt and the flicker member 72, the rotational torque increases. However, in the present invention, since there is a brush only at the position of the paper feed roller, the torque can be reduced and energy can be saved. Necessary functions can be obtained.)

FIG. 2 is an enlarged view of the secondary transfer device 22 when the secondary transfer roller 73 is used in the secondary transfer device 22.
FIG. 3 is a top view thereof.
The secondary transfer roller is configured by coating elastic rubber with a surface layer material of fluororesin. (Coating to reduce toner adhesion to the transfer roller surface and weaken friction with the cleaning blade)
As in the secondary transfer apparatus of FIG. 1, the toner is in contact with the intermediate transfer member 10, and therefore, the toner on the belt on the intermediate transfer member 10 on the belt between the portions where the transfer material s such as transfer paper does not come or between the sheets. Since the process pattern is transferred, the cleaning blade 71 is provided to remove the toner on the secondary transfer roller 73.

The brush roller 70 is in contact with the secondary transfer roller with an amount of biting “a” upstream of the cleaning blade to prevent paper dust from being caught in the blade 71.
As shown in FIG. 3, a paper dust removing brush roller 70 is installed at a position corresponding to the position of the paper feeding roller 50 (only in the central portion). It is configured to be long.
Here, the paper dust removing brush roller is not disposed on the entire surface, and only the position corresponding to the paper feeding roller position is set, so that the rotational torque of the brush roller becomes ¼ or less, and the motor (not suitable for rotating the brush roller) The power saving can be obtained by reducing the load torque (shown).
In this embodiment, the brush roller 70 is biased to further improve the paper dust removal effect and toner removal effect.

Further, it is made of a polyester resin material so that the outer diameter of the brush roller 70 hardly changes (the outer diameter of the brush roller hardly changes with time). Transfer with Φ16mm, acrylic carbon, 6.25D / F, 50,000 / inch ² , E + 7Ω, rotating in the same rotation direction (counter direction) as the transfer roller, and scraped by the brush roller 70 Paper dust and toner on the roller 73 are blown off by the brush roller 70 coming into contact with a resin-made flicker member 72, transported to the back side of the machine by a recovery coil 74, and transported to a waste toner bottle (not shown). ing.

Here, FIG. 4 shows a result of passing 50,000 sheets of recycled paper in which the transfer device 22 of FIG. 2 is put in the image forming apparatus of FIG. This is a result of passing the paper while shaking the amount A of the secondary transfer roller biting the brush roller 70.
Conventionally, when the amount A of biting into the secondary transfer roller of the brush roller is 1 mm or less, a cleaning failure has occurred due to paper dust being caught in the blade, but the amount of biting A into the secondary transfer roller is 1 mm or more. Then, even if 50,000 sheets were passed, no cleaning failure occurred and the secondary transfer blade had almost no paper dust, and the paper dust removal effect by the brush roller 70 was obtained.

1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention. 1 is a schematic configuration diagram of a secondary transfer apparatus showing an embodiment of the present invention. It is said top view. FIG. 3 is a diagram illustrating a result of passing 50,000 sheets of recycled paper in which paper dust is easily generated using the secondary transfer apparatus of FIG. 2 in the image forming apparatus of FIG.

Explanation of symbols

10 Intermediate transfer member 14, 15, 16 Support roller 17 Intermediate transfer member cleaning device (cleaning means)
18 Image forming means 20 Tandem image forming apparatus 21 Exposure apparatus 22 Secondary transfer apparatus (secondary transfer section)
23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 30 Document table 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Photosensitive member (image carrier) body)
42 Paper feed roller 43 Paper bank 44 Paper cassette 45 Paper dust separation roller 46 Paper feed path 47 Transport roller 48 Paper feed path 49 Registration roller 50 Paper feed roller 51 Manual tray 52 Separation roller 53 Manual paper feed path 55 Switching claw 56 Ejection Roller 57 Paper discharge tray 70 Paper dust removing brush roller 71 Secondary transfer cleaning blade 72 Flicker member 73 Secondary transfer roller 74 Collection coil 100 Copying device main body 200 Paper feed table,
300 scanner,
400 Automatic Document Feeder (ADF)

Claims (5)

An endless intermediate transfer belt that is stretched and rotated by several rollers, and an image forming unit and a secondary transfer body disposed along the intermediate transfer belt, and an image carrier of the image forming unit An image forming apparatus that transfers a toner image formed thereon onto an intermediate transfer belt, and transfers and transports the toner image onto a transfer material on a secondary transfer body. The secondary transfer body includes a cleaning unit, and includes a cleaning unit. In the image forming apparatus comprising a rubber blade that is in constant contact with the secondary transfer member,
An image is characterized in that a rotatable roller-like brush member is provided on the upstream side of the cleaning means in the rotation direction of the secondary transfer member, and the brush member is attached only to a paper feeding and conveying roller position. Forming equipment. The image forming apparatus according to claim 1.
An image forming apparatus, wherein an amount of biting of the brush member with respect to the secondary transfer member is 1 mm or more. The image forming apparatus according to claim 1, wherein
An image forming apparatus, wherein a flicker member is brought into contact with the brush member. The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus, wherein the brush member is made of polyester resin. The image forming apparatus according to claim 1,
An image forming apparatus, wherein a bias is applied to the brush member.

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