JP3048996B2 - Sheet separation mechanism and image forming apparatus provided with this sheet separation mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet separating mechanism and an image forming apparatus provided with the sheet separating mechanism, and more particularly, to a sheet separating mechanism used when forming an image on a sheet by using an electrophotographic method, and the sheet separating mechanism. The present invention relates to an image forming apparatus provided with a mechanism.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus using an electrophotographic system is used for a copying machine, a printer, a plotter, a facsimile machine and the like. FIG. 6 shows an example of the sheet separating mechanism used in the image forming apparatus. The transfer roller 45 transfers the toner image formed on the photoconductor, and further transfers the transferred toner image to a sheet. Cleaning roller 47
Cleans the toner remaining on the transfer roller 45 without being transferred to the sheet. The separation claws 48a, 48b and 48c prevent the paper from being wound around the transfer roller 45. Butt roller 5
3a, 53b, 53c are separation claws 48a, 48b, 48
It is used to keep the distance between c and the transfer roller 45 constant. The springs 52a, 52b, 52c
A load is generated for pressing the cleaning rollers 47 a, 48 b, and 48 c against each other.

Generally, when the transfer roller 45 is a metal roller, the separation claws 48a, 48b, and 48c are connected to the transfer roller 45.
Although they are arranged in contact with the surface, if the surface of the transfer roller 45 is made of rubber, the separation claws 48a, 48b, 48
If the contact c is made, the surface of the transfer roller 45 will be scratched. However, it is difficult to keep the interval constant, and if the interval is narrow, the transfer roller 45 may be damaged. If the interval is too wide, the paper cannot be separated satisfactorily. In order to avoid this, abutting rollers 53a, 53b, 53c and the like are arranged between the transfer roller 45 and the separation claws 48a, 48b, 48c.

FIG. 6 illustrates the separation claw of the transfer roller. However, in an electrophotographic image forming apparatus, the separation claw is also used for the fixing roller or the photosensitive member. A configuration similar to the above may be used to keep a constant distance from the body.

[0005]

In the above-mentioned conventional paper separating mechanism, the contact roller is used as a means for keeping the interval between the transfer roller and the separation claw constant, so that the number of parts increases and the mechanism becomes complicated. In addition, there is a problem that the manufacturing process becomes complicated and the manufacturing cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet separating mechanism for reliably positioning a separating claw with a simple mechanism and an image forming apparatus provided with the sheet separating mechanism.

[0007]

According to the present invention, there is provided a paper separating mechanism of an image forming apparatus for printing on paper using an electrophotographic method, wherein a cleaning roller for cleaning the surface of the rubber roller is pressed against a rubber roller. And a separation claw for separating the paper from the rubber roller is arranged so as to be positioned by the cleaning roller, and a gap between the rubber roller and the separation claw is set.
It is characterized by keeping it constant .

The paper separating mechanism according to the present invention includes a transfer roller for transferring an image transferred from a photoreceptor onto a sheet, a cleaning roller pressed against the transfer roller to clean the surface of the transfer roller, and a transfer roller. and a separation claw for preventing the paper to wrap around the rollers, have a row by the cleaning roller positioning with respect to the transfer roller of the separation claw, and said transfer roller and the separation claw
The interval may be kept constant .

The paper separating mechanism of the present invention includes a fixing roller for fixing an image on a sheet to the sheet, a cleaning roller pressed against the fixing roller to clean the surface of the fixing roller, and a sheet for fixing the sheet to the fixing roller. And a separation claw that prevents the separation claw from being wound, and the cleaning roller performs positioning of the separation claw with respect to the fixing roller.
Alternatively, the distance between the fixing roller and the separation claw may be kept constant .

The paper separating mechanism of the present invention includes a photosensitive member for forming an image to be transferred onto a sheet on a surface thereof, a cleaning roller pressed against the photosensitive member to clean the surface of the photosensitive member, and a separation claw for preventing the paper winds around, have rows by the cleaning roller positioning relative to the photosensitive member of the separation claw, the photosensitive
The distance between the body and the separation claw may be kept constant .

An image forming apparatus according to the present invention is an image forming apparatus for printing on paper using an electrophotographic method, wherein a cleaning roller for cleaning the surface of the rubber roller is pressed against a rubber roller, and the paper is transferred from the rubber roller to the paper. A separating claw for separating the rubber roller is positioned so as to be positioned by the cleaning roller.
A paper separating mechanism for maintaining a constant distance from the separating claw is provided.

An image forming apparatus according to the present invention includes a transfer roller for transferring an image transferred from a photoreceptor to a sheet, a cleaning roller pressed against the transfer roller to clean the surface of the transfer roller, and a transfer roller. and a separation claw for preventing the paper to wrap around the rollers, have a row by the cleaning roller positioning with respect to the transfer roller of the separation claw, and said transfer roller and the separation claw
A paper separating mechanism for keeping the interval constant may be provided.

An image forming apparatus according to the present invention includes: a fixing roller for fixing an image on a sheet to the sheet; a cleaning roller for pressing the fixing roller to clean the surface of the fixing roller; And a separation claw for preventing winding of the separation claw, and positioning of the separation claw with respect to the fixing roller is performed by the cleaning roller.
Alternatively, a paper separation mechanism may be provided to keep the distance between the fixing roller and the separation claw constant .

An image forming apparatus according to the present invention comprises: a photosensitive member for forming an image to be transferred onto a sheet on a surface; a cleaning roller pressed against the photosensitive member to clean the surface of the photosensitive member; and a separation claw for preventing the paper winds around, have rows by the cleaning roller positioning relative to the photosensitive member of the separation claw, the photosensitive
A paper separating mechanism for maintaining a constant distance between the body and the separation claw may be provided.

[0015]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing the configuration of the first embodiment of the present invention. The first embodiment is a color electrophotographic image forming apparatus.

The photosensitive drum 1 is charged to a predetermined potential by a charging means 2 and an electrostatic latent image is formed by an exposure means 3 comprising a laser beam or an LED, and a developing means 4 containing a plurality of color toners therein. As a result, a toner image is formed. The transfer roller 5 transfers the toner image on the photosensitive drum 1. The above process is repeated a plurality of times to form a color image on the transfer roller 5, and when a predetermined image is formed on the transfer roller 5, the paper 9 is transported between the transfer roller 5 and the transport roller 6, and Is transferred to the sheet 9. The fixing unit 14 fixes the toner image on the paper 9. When the paper 9 passes between the transfer roller 5 and the transport roller 6, there is a toner image on the transfer roller 5. Therefore, when the paper 9 is thin, the paper tends to wind around the transfer roller 5. The separation claw 8 is arranged to prevent this winding. The cleaning roller 7 is pressed against the transfer roller 5 with a predetermined pressure, and collects residual toner that has not been transferred to the sheet 9 on the transfer roller 5. As the transfer roller 5, a rubber roller whose outer periphery is covered with a rubber material is used. Silicon or urethane is suitable as the rubber material.

FIG. 2 is an enlarged sectional view of the sheet separating mechanism.
Below the cleaning roller 7 pressed against the transfer roller 5, a cleaning blade 10 for scraping off residual toner and the like collected by the cleaning roller 7 and a collection box 11 are arranged. The spring 12 generates a load for pressing the separation claw 8 against the cleaning roller 7.

FIG. 3 is a perspective view of the sheet separating mechanism. A plurality of separation claws 8a, 8b and 8c are arranged in the longitudinal direction of the transfer roller 5, and are pressed against the cleaning roller 7 by springs 12a, 12b and 12c, respectively.

Next, the operation will be described. When a color image is formed by an electrophotographic image forming apparatus, the photosensitive drum 1 is charged by a charging unit 2 at a potential of several hundred volts, and is exposed by an exposure unit 3 in accordance with an image to be formed. Since the potential of the exposed portion on the photosensitive drum 1 decreases, the toner charged by the developing unit 4 adheres to the portion of the photosensitive drum 1 where the potential has decreased and appears as a toner image. The toner image on the photosensitive drum 1 is transferred onto the transfer roller 5 by electrostatic force or adhesive force. The developing unit 4 contains yellow, magenta, cyan, and black toners, and a full-color image is formed on the transfer roller 5 by repeating the above-described developing process four times. When the image formation on the transfer roller 5 is completed, the paper 9 is conveyed and conveyed between the transfer roller 5 and the conveyance roller 6. When the paper 9 passes between the transfer roller 5 and the transport roller 6, the toner image on the transfer roller 5
The toner image is transferred to the paper 9 by the fixing unit 14.
Is established. The transfer efficiency when the toner image on the transfer roller 5 is transferred to the paper 9 is preferably 100%.
If it is not 0%, the toner image remains on the transfer roller 5. A cleaning roller 7 made of a material that easily absorbs the toner image is pressed against the transfer roller 5.
Adsorbs residual toner on the transfer roller. Further, the remaining toner adsorbed on the cleaning roller 7 is scraped off by the cleaning blade 10 and collected in the collection box 11.

Next, a second embodiment of the present invention will be described. FIG. 4 is a sectional view showing the configuration of the second embodiment. In the second embodiment, the first embodiment is applied to a fixing unit. The fixing unit 14 includes a fixing roller 15, a backup roller 16, a cleaning roller 17, a separating claw 18, and a spring 22. The fixing roller 15 has a heat source inside, and conveys the sheet 9 to and from the backup roller 16 to fix the toner image 19 on the sheet 9. As the fixing roller 15, a rubber roller whose outer periphery is covered with a rubber material such as silicon is used. The cleaning roller 17 cleans toner adhered to the fixing roller 15.
The separation claw 18 is arranged to prevent the paper 9 from being caught in the fixing roller 15. Here, the separation claw 18 is, like the separation claw 8 of the first embodiment, a spring 22.
As a result, the cleaning roller 17 is brought into pressure contact with the fixing roller 15 to keep a constant distance from the fixing roller 15.

In FIG. 4, the cleaning roller 17 and the separation claw 18 are arranged on the fixing roller 15 side.
Cleaning and prevention of winding of the sheet 9 around the backup roller 16 can also be performed.

Next, a third embodiment of the present invention will be described. FIG. 5 is a sectional view showing the configuration of the third embodiment. The third embodiment is an example in which the first embodiment is applied to a photoconductor, and is an example in which intermediate transfer is not performed and transfer is performed directly from the photoconductor to paper.

The photosensitive drum 1 is a drum-shaped photosensitive member. A toner image is formed on the surface of the photosensitive drum 1 by a charging unit 2, an exposing unit 3, and a developing unit 24. Photosensitive drum 1 and transfer device 2
6, the toner image on the photosensitive drum 1 is transferred to the paper 9. The cleaning roller 27 cleans toner remaining on the photosensitive drum 1 without being transferred onto the sheet 9. The separation claw 28 is arranged to prevent the paper 9 from being caught in the photosensitive drum 1. Here, separation claw 2
Like the separation claw 8 in the first embodiment, the spring 8 is pressed against the cleaning roller 27 by a spring 32 to keep a constant distance from the photosensitive drum 1.

With the above structure, when the surface of the photosensitive member is made of a soft material, the surface of the photosensitive member is prevented from being damaged,
In addition, the separation claw can be accurately arranged with a simple mechanism. Since the separation claw does not come into contact with the photoreceptor, even when the surface of the photoreceptor is hard, an effect of preventing an adverse effect on the image due to the contact of the separation claw with the surface of the photoreceptor is also provided.

[0025]

As described above, according to the present invention, the cleaning roller is disposed between the transfer roller and the separation claw, and the separation claw is pressed against the cleaning roller, whereby the separation between the separation claw and the transfer roller is reduced. Since the control can be performed with the dimensional accuracy of the roller, there is an effect that the distance between the separation claw and the transfer roller can be accurately maintained. The same effect can be obtained with the fixing roller and the separation claw of the photoconductor.

Conventionally, in order to accurately arrange a separating claw such as a rubber roller including a transfer roller, a contact roller is pressed between the rubber roller and the separation claw. By substituting the cleaning roller, there is an effect that the number of parts is reduced, the mechanism is simplified, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a sectional view of a sheet separating mechanism.

FIG. 3 is a perspective view of a sheet separating mechanism.

FIG. 4 is a sectional view showing a configuration of a second exemplary embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of a third exemplary embodiment of the present invention.

FIG. 6 is a perspective view showing a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 charging means 3 exposure means 4 developing means 5 transfer roller 6 transport roller 7 cleaning roller 8, 8a, 8b, 8c separation claw 10 cleaning blade 11 collection box 12, 12a, 12b, 12c spring 14 fixing means 15 fixing roller Reference Signs List 16 backup roller 17 cleaning roller 18 separation claw 19 toner image 22 spring 24 developing means 26 transfer unit 27 cleaning roller 28 separation claw 32 spring

Claims (10)

(57) [Claims] In a paper separating mechanism of an image forming apparatus for printing on paper using an electrophotographic method, a cleaning roller for cleaning a surface of the rubber roller is pressed against a rubber roller, and the paper is separated from the rubber roller. The rubber roller and the separation claw are arranged so as to be positioned by the cleaning roller.
The paper separation mechanism is characterized in that the interval between the paper and the paper is kept constant . 2. A transfer roller for transferring an image transferred from a photoreceptor onto a sheet, a cleaning roller pressed against the transfer roller to clean a surface of the transfer roller, and the sheet being wound around the transfer roller. and a separation claw to prevent the stick, have rows by the cleaning roller positioning with respect to the transfer roller of the separation claw, before
A sheet separating mechanism for maintaining a constant distance between the transfer roller and the separation claw . 3. The paper separating mechanism according to claim 2, wherein the transfer roller is a roller whose surface is made of a rubber material. 4. The sheet separating mechanism according to claim 2, wherein a plurality of the separating claws are arranged in a longitudinal direction of the transfer roller, and are pressed against the cleaning roller by a spring. 5. A fixing roller for fixing an image on a sheet to the sheet, a cleaning roller pressed against the fixing roller to clean the surface of the fixing roller, and preventing the sheet from wrapping around the fixing roller. and a separation pawl, have rows by the cleaning roller positioning with respect to the fixing roller of the separation claw, and the fixing roller
A sheet separating mechanism, wherein a distance between the sheet and the separating claw is kept constant . 6. A photoreceptor for forming an image to be transferred onto a sheet on the surface, a cleaning roller pressed against the photoreceptor to clean the surface of the photoreceptor, and the sheet being wound around the photoreceptor. and a separation claw for preventing, have rows by the cleaning roller positioning relative to the photosensitive member of the separation claw, the distance between the photosensitive member and the separating claw
Paper separation mechanism, characterized in that the paper is kept constant . 7. An image forming apparatus for printing on paper using an electrophotographic method, wherein a cleaning roller for cleaning the surface of the rubber roller is disposed in pressure contact with the rubber roller,
A separation claw for separating the paper from the rubber roller is disposed so as to be positioned by the cleaning roller, and a gap between the rubber roller and the separation claw is set to one.
An image forming apparatus, comprising: a paper separating mechanism for keeping the paper constant . 8. A transfer roller for transferring an image transferred from a photoreceptor onto a sheet, a cleaning roller pressed against the transfer roller to clean a surface of the transfer roller, and the sheet being wound around the transfer roller. and a separation claw to prevent the stick, have rows by the cleaning roller positioning with respect to the transfer roller of the separation claw, before
An image forming apparatus, comprising: a sheet separating mechanism for maintaining a constant distance between the transfer roller and the separation claw . 9. A fixing roller for fixing an image on a sheet to the sheet, a cleaning roller pressed against the fixing roller to clean the surface of the fixing roller, and preventing the sheet from wrapping around the fixing roller. and a separation pawl, have rows by the cleaning roller positioning with respect to the fixing roller of the separation claw, and the fixing roller
An image forming apparatus comprising a sheet separating mechanism for keeping a constant distance from the separation claw . 10. A photoreceptor for forming an image to be transferred onto a sheet on a surface thereof, a cleaning roller pressed against the photoreceptor to clean the surface of the photoreceptor, and the sheet being wound around the photoreceptor. and a separation claw for preventing, have rows by the cleaning roller positioning relative to the photosensitive member of the separation claw, between the photosensitive member and the separating claw
An image forming apparatus comprising a sheet separating mechanism for keeping a constant gap .