JP5452010B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile machine.

  In an image forming apparatus that forms a desired image on a sheet or the like, for example, a toner image is primarily transferred from a photoreceptor to a transfer surface of a transfer belt, and then the toner image that has been primarily transferred is secondarily transferred to a sheet or the like to form an image. I do. In general, the image forming apparatus includes a cleaning device having a cleaning member to which a bias is applied, and the toner remaining on the transfer surface after the secondary transfer is mechanically and mechanically prevented from causing image formation defects in the next transfer. It is configured to be electrically removed.

As an image forming apparatus provided with such a cleaning device, for example, the one described in Patent Document 1 is known. Japanese Patent Application Laid-Open No. H10-228561 discloses a technique in which a pretreatment member such as a blade or a roll is provided on the upstream side of the cleaning device so as to improve the cleaning performance of the cleaning device, and the toner is pretreated.
JP 2005-250411 A

  However, if the pretreatment member is provided so as to be in sliding contact with the transfer surface in order to improve the cleaning performance of the cleaning device as in Patent Document 1, the toner remaining on the transfer surface is scattered, and more particularly than the position of the pretreatment member. There is a problem that toner is scattered on the upstream side. The scattered toner may contaminate the photoconductor disposed in the apparatus, the optical system, the charger, and the like, and cause various image formation defects.

  The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus capable of improving cleaning properties and suppressing image formation defects.

In order to solve the above problems, the present invention provides a transfer belt on which a toner image is transferred to a transfer surface and runs endlessly, and a cleaning device that electrically adsorbs and removes toner remaining on the transfer surface. An image forming apparatus including: a pre-cleaning device that is in sliding contact with the transfer surface upstream of a position where the cleaning device is provided and performs pre-processing for the adsorption to the toner; and the pre-cleaning device. Adopting a structure having an anti-scattering member provided on the upstream side from the provided position and having a width larger than the width of the transfer belt and preventing the toner from scattering to the upstream side by the sliding contact. To do.
By adopting such a configuration, in the present invention, it is possible to suppress the toner from being scattered upstream from the position where the pre-cleaning device is provided.

Further, in the present invention, a configuration is adopted in which the scattering prevention member is provided so as to shield the space above the transfer surface on the upstream side.
By adopting such a configuration, in the present invention, since the upper space on the upstream side of the pre-cleaning device is shielded, the scattering of the toner on the upstream side is suppressed.

In the present invention, a configuration is adopted in which the scattering prevention member is provided so as to be in sliding contact with the transfer surface.
By adopting such a configuration, in the present invention, the toner is prevented from scattering into the apparatus from the gap between the scattering prevention member and the transfer surface, and the toner is more reliably suppressed from scattering upstream. The

Moreover, in this invention, the structure that the said scattering prevention member has electroconductivity is employ | adopted.
By adopting such a configuration, in the present invention, since the scattering prevention member has conductivity, the accumulation of electric charges is suppressed, and the toner is attracted by frictional charging by sliding contact with the transfer surface. Thus, the scattering of toner is suppressed.

Moreover, in this invention, the structure that the said scattering prevention member is electrically grounded is employ | adopted.
By adopting such a configuration, in the present invention, it is possible to maintain the sliding contact state with the transfer surface without accumulating charges in the scattering prevention member, and the toner is frictionally charged by sliding contact with the transfer surface. The toner is more reliably suppressed from being scattered at the sliding contact position.

Moreover, in this invention, the structure that the said scattering prevention member is electrically grounded and is supported by the holder member which has electroconductivity is employ | adopted.
By adopting such a configuration, in the present invention, the scattering prevention member is electrically grounded via the holder member.

In the present invention, the pre-cleaning device employs a configuration having a brush member that is in sliding contact with the transfer surface.
By adopting such a configuration, in the present invention, the toner remaining on the transfer surface is disturbed by the brush, whereby the suction processing of the downstream cleaning device can be effectively performed.

Moreover, in this invention, the structure that the said scattering prevention member consists of a flexible sheet | seat member is employ | adopted.
By adopting such a configuration, in the present invention, it is possible to suppress the toner from being scattered to the upstream side by the sheet member, and since it has flexibility, it can be freely deformed to be in close contact with the transfer surface. It becomes.

According to the present invention, there is provided an image forming apparatus having a transfer belt on which a toner image is transferred to a transfer surface and running endlessly, and a cleaning device that electrically adsorbs and removes toner remaining on the transfer surface. A pre-cleaning device that is in sliding contact with the transfer surface upstream of the position where the cleaning device is provided and pre-treats the toner for the adsorption, and upstream of the position where the pre-cleaning device is provided. And a scattering prevention member that prevents the toner from scattering to the upstream side due to the sliding contact, and the toner is scattered upstream from the position where the pre-cleaning device is provided. Is suppressed.
Therefore, according to the present invention, there is an effect that it is possible to provide an image forming apparatus that improves cleaning properties and suppresses image formation defects.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description, an example in which the present invention is applied to a printer (image forming apparatus) will be described. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

First, the configuration of the printer P in the present embodiment will be described with reference to FIG.
FIG. 1 is a schematic diagram illustrating a configuration of a printer P according to an embodiment of the present invention.
As shown in FIG. 1, the printer P includes an image forming unit 2 that forms an image, a paper feed cassette 3 that stores paper, and a secondary transfer unit that transfers an image formed by the image forming unit 2 to paper. 4, a fixing unit 5 that fixes the transferred image on the paper, a paper discharge tray 6 that receives the discharged paper after the fixing is completed, and a conveyance path that conveys the paper from the paper feed cassette 3 to the paper discharge tray 6. 7.

  The image forming unit 2 forms an endlessly running intermediate transfer belt (transfer belt) 21 and toner images corresponding to yellow (Y), magenta (M), cyan (C), and black (BK), respectively. In addition, an image forming unit F (FY, FM, FC, FK) for transferring the formed toner image to the transfer surface 21a of the intermediate transfer belt 21, and a cleaning device for removing the toner remaining on the transfer surface 21a of the intermediate transfer belt 21. 30, a pre-brush (pre-cleaning device) 100 provided on the upstream side of the cleaning device 30, and a toner scattering prevention sheet (scattering prevention member) 110 provided on the upstream side of the pre-brush 100.

The intermediate transfer belt 21 is stretched around a driving roller 22 and a driven roller 23, and is configured to endlessly rotate counterclockwise in FIG.
The drive roller 22 is connected to a drive unit having a drive source such as a motor, and rotates while applying a grip force to the intermediate transfer belt 21. The driven roller 23 is driven to rotate following the rotational drive of the drive roller 22.

The image forming unit F includes a photoreceptor 10, a charger 11, an exposure device 12, a developing device 13, and a primary transfer roller 14, and further includes a cleaning device, a charge removal device, and the like (not shown).
The photoconductor 10 is formed in a cylindrical shape, and an electrostatic latent image and a toner image based on the electrostatic latent image are formed on the peripheral surface thereof. The charger 11 is disposed so as to face the photoconductor 10 and charges the peripheral surface of the photoconductor 10. The exposure device 12 scans the peripheral surface of the charged photoconductor 10 with laser light emitted based on image data in the print format. The developing device 13 develops a toner image based on the electrostatic latent image on the peripheral surface of the photoconductor 10 by supplying toner to the peripheral surface of the photoconductor 10. The primary transfer roller 14 is disposed to face the photoconductor 10 with the intermediate transfer belt 21 interposed therebetween, and primarily transfers the toner image developed on the photoconductor 10 to the intermediate transfer belt 21.

The paper feed cassette 3 can be pulled out with respect to the apparatus main body, and is configured to store paper.
The secondary transfer unit 4 performs secondary transfer of an image formed on the intermediate transfer belt 21 onto a sheet. The secondary transfer unit 4 drives the intermediate transfer belt 21 with the driving roller 22 and the intermediate transfer belt 21 interposed therebetween. A secondary transfer roller 41 disposed opposite to the roller 22 is provided.
The fixing unit 5 fixes the image secondarily transferred onto the sheet, and includes a heating roller 51 that fixes the toner by applying pressure and heating.
The conveyance path 7 includes a pickup roller 71 that carries out the paper from the paper feed cassette 3, a paper feed roller 72 that carries the paper, a paper discharge roller 73 that discharges the paper to the paper discharge tray 6, and the like.

Next, the configuration of the cleaning device 30, the pre-brush 100, and the toner scattering prevention sheet 110 will be described in detail with reference to FIGS.
FIG. 2 is an enlarged view of a portion where the intermediate transfer belt 21 is provided in the embodiment of the present invention.
FIG. 3 is an enlarged view of a main part of a portion where the cleaning device 30, the pre-brush 100, and the toner scattering prevention sheet 110 are provided in the embodiment of the present invention.
FIG. 4 is a perspective view illustrating configurations of the pre-brush 100 and the toner scattering prevention sheet 110 according to the embodiment of the present invention.

  The cleaning device 30, the pre-brush 100, and the toner scattering prevention sheet 110 are provided downstream of the position where the secondary transfer unit 4 is provided and upstream of the position where the photoconductor 10 of the image forming unit F is provided. Yes. Further, as shown in FIG. 2, the toner scattering prevention sheet 110, the pre-brush 100, and the cleaning device 30 are provided in this order from the upstream side.

As shown in FIG. 3, the cleaning device 30 schematically includes a brush roller 31, a metal roller 32, and a screw 33.
The brush roller 31 is provided with a brush on its peripheral surface, and the brush is in contact with the transfer surface 21a. The brush roller 31 is configured to rotate in the direction opposite to the running direction of the transfer surface 21a (counterclockwise in FIG. 3). Further, the brush roller 31 is configured to be electrically attracted with charged toner by applying a bias from a bias power source (not shown).

The metal roller 32 rotates clockwise in FIG. 3 and is disposed so as to contact the brush roller 31. The metal roller 32 is configured to receive toner from the brush roller 31 and convey the received toner to the collection chamber 30A side where the screw 33 is provided. A blade 30A1 formed of an elastic member such as rubber is provided on the collection chamber 30A side, and the toner on the peripheral surface of the metal roller 32 is scraped off by the blade 30A1. In the collection chamber 30A, a PET film 30A2 is installed so that the scraped toner does not return to the metal roller 32 side.
The screw 33 is configured to convey the toner scraped off from the metal roller 32 by being rotationally driven to, for example, a disposal unit outside the cleaning device 30.

The pre-brush 100 is a fixed brush that is raised vertically downward, and is arranged so that a tip portion thereof is in contact with the transfer surface 21a. The prebrush 100 is fixed to a holder member 120 installed above the transfer surface 21a (see FIG. 4).
The pre-brush 100 floats the toner on the transfer surface 21a by physically disturbing the toner that is electrically adsorbed on the transfer surface 21a by slidingly contacting the transfer surface 21a on the upstream side of the cleaning device 30 ( By doing so, the cleaning performance by the brush roller 31 on the downstream side is improved.

  As shown in FIG. 3, the toner scattering prevention sheet 110 is located upstream of the position where the prebrush 100 is provided so as to prevent the toner scattering at the upstream sliding position between the prebrush 100 and the transfer surface 21 a. Arranged on the side. The toner scattering prevention sheet 110 is composed of a conductive sheet member having flexibility such as a conductive urethane sheet or a conductive PET film. The toner scattering prevention sheet 110 has a width larger than the width of the intermediate transfer belt 21, and is disposed so that the base end portion 111 is supported by the holder member 120 and the front end portion 112 is in sliding contact with the transfer surface 21a. The toner scattering prevention sheet 110 is provided on the upstream side of the pre-brush 100 so as to shield the upper space X of the transfer surface 21a.

  The holder member 120 is provided with a prebrush 100 on the downstream side and a toner scattering prevention sheet 110 on the upstream side, and is fixed to an intermediate transfer unit casing 21A that supports the intermediate transfer belt 21 via a screw member 121 (see FIG. 3 and FIG. 4). The holder member 120 is fixed so that the pre-brush 100 and the toner scattering prevention sheet 110 are in proper contact with the transfer surface 21a. The holder member 120 has a width larger than that of the intermediate transfer belt 21 and is formed of a sheet metal that is electrically grounded and has conductivity.

Next, a cleaning operation by the printer P having the above configuration will be described.
The printer P transfers the toner image formed by the image forming unit F to the sheet by the secondary transfer unit 4 shown in FIG. The untransferred toner that has passed through the secondary transfer portion 4 is conveyed downstream while adhering to the transfer surface 21a.

As shown in FIG. 3, a toner scattering prevention sheet 110 is disposed on the downstream side so as to be in sliding contact with the transfer surface 21a. The toner attached to the transfer surface 21a bends the toner scattering prevention sheet 110 and passes through a position where the toner scattering prevention sheet 110 is provided.
Here, since the toner scattering prevention sheet 110 is electrically grounded via the holder member 120, frictional charging due to sliding contact with the transfer surface 21a is suppressed. That is, by using the toner scattering prevention sheet 110 as a conductive sheet member, it is possible to maintain a sliding contact state with the transfer surface 21a without accumulating static electricity. The toner is prevented from scattering at the sliding contact position.

A pre-brush 100 is disposed on the downstream side of the toner scattering prevention sheet 110 so as to be in sliding contact with the transfer surface 21a. The toner adhering to the transfer surface 21a passes through a position where the toner scattering prevention sheet 110 is provided, and is then preprocessed by the pre-brush 100.
Specifically, the pre-brush 100 physically disturbs the toner that is electrically adsorbed on the transfer surface 21a by being in sliding contact with the transfer surface 21a on the upstream side of the cleaning device 30, thereby causing the pre-brush 100 on the transfer surface 21a. The toner is floated (displaced) to improve the adsorption efficiency of the brush roller 31 on the downstream side.

  At this time, although the toner may be scattered upstream from the sliding contact position of the pre-brush 100, the toner scattering prevention sheet 110 and the holder member 120 cooperate to shield the upper space X of the transfer surface 21a. The toner is prevented from scattering upstream from the toner scattering prevention sheet 110. Further, since the toner scattering prevention sheet 110 is flexible and freely deforms so as to be in close contact with the transfer surface 21a, the toner is scattered in the apparatus from the gap between the toner scattering prevention sheet 110 and the transfer surface 21a. Is prevented.

The toner that has passed through the pre-brush 100 is removed from the transfer surface 21a by the cleaning device 30 provided on the downstream side.
Specifically, the toner is attracted to the brush roller 31 from the transfer surface 21a by a physical action in which the brush roller 31 rotates while being in contact with the transfer surface 21a and an electrical action by applying a bias. The toner adsorbed on the brush roller 31 is conveyed to the collection chamber 30A side by the metal roller 32 and scraped off by the blade 30A1. Then, the scraped toner is conveyed outside the cleaning device 30 by the screw 33.

Therefore, according to the above-described embodiment, the toner image is transferred to the transfer surface 21a, and the intermediate transfer belt 21 that runs endlessly, and the cleaning device that electrically adsorbs and removes the toner remaining on the transfer surface 21a. 30, a pre-brush 100 that is in sliding contact with the transfer surface 21 a upstream of the position where the cleaning device 30 is provided and performs pre-processing for the above-described adsorption of the toner, and the pre-brush 100 are provided. By adopting a configuration provided with a toner scattering prevention sheet 110 that is provided on the upstream side of the position and prevents the scattering of the toner to the upstream side by the sliding contact, the upstream side from the position where the prebrush 100 is provided. Therefore, the scattered toner is charged such as the photosensitive member 10 disposed in the apparatus. Contaminating 11 or the like is prevented to cause various image formation failure or the like.
Therefore, in this embodiment, there is an effect that it is possible to provide the printer P that improves the cleaning property and suppresses image formation defects.

  In the present embodiment, the toner scattering prevention sheet 110 is provided on the upstream side so as to shield the upper space X of the transfer surface 21a. By shielding the upper space X, the toner is prevented from scattering to the upstream side.

  In the present embodiment, the toner scattering prevention sheet 110 is provided so as to be in sliding contact with the transfer surface 21a, so that the toner is discharged from the gap between the toner scattering prevention sheet 110 and the transfer surface 21a. It is prevented that the toner scatters in the apparatus, and the toner is more reliably prevented from scattering to the upstream side.

  Further, in the present embodiment, the toner scattering prevention sheet 110 is configured to have conductivity so that accumulation of electric charges is suppressed, and the toner is attracted by frictional charging by sliding contact with the transfer surface 21a. The toner can be passed without being scattered at the sliding contact position.

  Further, in the present embodiment, the toner scattering prevention sheet 110 is electrically grounded, so that the toner scattering prevention sheet 110 does not accumulate charges and is in sliding contact with the transfer surface 21a. Therefore, it is possible to more reliably suppress toner scattering at the sliding contact position.

  In the present embodiment, the toner scattering prevention sheet 110 is electrically grounded and supported by a conductive holder member 120, thereby preventing toner scattering via the holder member 120. The sheet 110 is electrically grounded.

  Further, in the present embodiment, by adopting a configuration in which the pre-brush 100 is in sliding contact with the transfer surface 21a, the toner remaining on the transfer surface 21a is disturbed by the brush, so that the suction of the downstream cleaning device 30 is effective. Can be performed automatically.

  In the present embodiment, the toner scattering prevention sheet 110 is configured by a flexible sheet member, so that the toner is prevented from scattering upstream by the sheet member, and the flexible sheet member is flexible. Therefore, it can be freely deformed to come into close contact with the transfer surface 21a.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above-described embodiment, it has been described that the pre-cleaning device includes the pre-brush 100. However, the present invention is not limited to the above-described configuration, and may be a member such as a blade or a sponge. Also good. However, if the pre-brush 100 is configured as in the present embodiment, the toner can pass through the raised gap without stagnation at the sliding contact position and go to the cleaning device 30 to improve the cleaning performance. Moreover, the prebrush 100 may be comprised from the member which has electroconductivity. According to this configuration, since the prebrush 100 is electrically grounded via the holder member 120, the toner can be directed to the cleaning device 30 without being electrically adsorbed to the prebrush 100, and the cleaning performance is improved. Is done.

Further, for example, in the present embodiment described above, the toner scattering prevention sheet 110 may be provided in a non-contact manner with the transfer surface 21a.
Further, in the above-described embodiment, the scattering prevention member is described as being configured from the toner scattering prevention sheet 110. However, the present invention is not limited to the above configuration. For example, the blade or the holder member 120 is provided. The upper space X may be bent to shield the upper space X.

1 is a schematic diagram illustrating a configuration of a printer according to an embodiment of the present invention. FIG. 3 is an enlarged view of a portion where an intermediate transfer belt is provided in an embodiment of the present invention. It is a principal part enlarged view of the site | part in which the cleaning apparatus, pre-brush, and toner scattering prevention sheet in embodiment of this invention are provided. It is a perspective view which shows the structure of the prebrush and toner scattering prevention sheet in embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Intermediate transfer belt (transfer belt), 21a ... Transfer surface, 30 ... Cleaning device, 100 ... Pre-brush (pre-cleaning device, brush member), 110 ... Toner scattering prevention sheet (scattering prevention member, sheet member), 120 ... Holder Member, P ... Printer (image forming apparatus), X ... Upper space

Claims (5)

An image forming apparatus comprising: a transfer belt on which a toner image is transferred to a transfer surface and running endlessly; and a cleaning device that electrically adsorbs and removes toner remaining on the transfer surface.
A pre-cleaning device that includes a brush member that is in sliding contact with the transfer surface upstream of a position where the cleaning device is provided, and that pre-treats the toner for the adsorption;
The sheet member is provided on the upstream side of the position where the brush member is provided and has a width and flexibility greater than the width of the transfer belt, and the toner is scattered to the upstream side by the sliding contact. possess a scattering prevention member for preventing,
The image forming apparatus , wherein the scattering prevention member is supported by a holder member provided with the brush member and is slidably contacted with the transfer surface together with the brush member .   The image forming apparatus according to claim 1, wherein the scattering prevention member is provided so as to shield an upper space of the transfer surface on the upstream side. The image forming apparatus according to claim 1 , wherein the scattering prevention member has conductivity. The image forming apparatus according to claim 3 , wherein the scattering prevention member is electrically grounded. The image forming apparatus according to claim 4 , wherein the holder member has conductivity and is electrically grounded .

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