JP2002351223A - Image forming device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent an increase in cost and an adverse electrical effect on a transfer operation, and to appropriately maintain holding strength of a sheet peeling member and contact pressure between a sheet peeling member and an image carrier. The present invention provides an image forming apparatus which can be stabilized by using the image forming apparatus. Kind Code: A1 A cleaning device that removes toner remaining on an image carrier after transfer at a downstream side of a transfer unit in a transfer direction of a transfer sheet material from a transfer unit where the toner image on the image carrier is transferred to a transfer sheet material. Below the apparatus 9, there is provided a stripping member 8 formed in a strip shape having a predetermined width, and the stripping member has a triangular stripping projection on the side of the image carrier at intervals in the length direction. A plurality of portions 8a are formed, and a side portion opposite to the image carrier side is adhered to a stationary portion 9 which forms the upper side of the transfer path of the transfer sheet material, and a tip of the peeling projection portion is provided on a peripheral surface of the image carrier. The transfer sheet material adhering to the peripheral surface of the image bearing member is always contacted to be peeled off.

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 using an electrophotographic method, such as a printer or a copying machine.
In particular, the present invention relates to an improvement in an operation of separating a transfer sheet material from an image carrier after the transfer operation.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, a separating charger is provided on the downstream side of a transfer section for separating a transfer sheet material from an image bearing member, and the image bearing member and the transfer sheet are separated by the separating charger. In some cases, a peeling operation is performed by electrically repelling the material.

[0003] However, in the case of using such a separation charger, electric parts and a control circuit for the separation charger are required, resulting in an increase in cost and an electric charge for the transfer operation of the transfer charger adjacent to the separation charger. There is a problem that it may have an adverse effect.

Another conventional example is disclosed in JP-A-9-28.
There was one described in FIG. 1810 as shown in FIGS. In FIG. 5, the photosensitive drum 16
Both ends are supported by a housing 18a of an image forming unit 18 containing a developing device, a cleaning device, and the like, and are driven to rotate in the direction of arrow b by a drive mechanism (not shown). Four separating claws 19 are arranged between the housing 18a and the photosensitive drum 16 at intervals in the length direction of the photosensitive drum 16.

[0005] The separation claw 19 is formed of an elastic plastic sheet material. The separation claw 19 has a front end 19a (a lower end in FIG. 5) formed in a triangular shape and a rear end (an upper end in FIG. 5) formed in a quadrangular shape, and the front end 19a slides on the photosensitive drum 16. , The rear end 19b
Is supported by the housing 18a.

As shown in FIG. 6, a U-shaped notch 19d is formed at the center of the separating claw 19 by pressing or the like, and the inside of the notch 19d is formed with respect to the outside of the notch 19d. Lifted tongue-shaped pressing piece 1
9e are formed. An opening 19c is formed at the mark where the pressing piece 19e inside the cut 19d is lifted.

In FIG. 7, a transfer sheet material (not shown) attached to the photosensitive drum 16 after passing through a contact portion (transfer portion) between the photosensitive drum 16 and the transfer roller 28 is separated.
At 0, it is peeled off from the photosensitive drum 16 by the tip 19a of the separation claw 19, and then is conveyed toward the fixing device on the right side in the figure.

The section of the housing 18a in the vicinity of the separating portion 30 has a substantially Z-shaped cross section, and a claw fitting portion 18b is provided below the Z-shaped portion of the housing 18a.
Are formed to protrude. And this claw fitting portion 18
The opening 19c of the separation claw 19 is fitted to the b. At this time, the pressing piece 19e of the separation claw 19 comes into contact with the slope formed on the claw fitting portion 18b, and the separation claw 19 contacts the photosensitive drum 16. Holds contact pressure.

[0009]

However, in such a conventional example, the transfer sheet material is separated from the peripheral surface of the photosensitive drum 16 by the tip portion 19a of the separation claw 19. Since the opening 19c of the separation claw 19 is fitted to the claw fitting portion 18b projecting downward from the housing 18a, the strength of holding the separation claw 19 in the housing 18a becomes unstable, and Claws 19
Is likely to fall from the housing 18a. Further, if the fitting is made tight to prevent this, there is a high possibility that the cut 19d of the separation claw 19 will be broken.

The contact pressure between the separation claw 19 and the photosensitive drum 16 is given by bending the pressing piece 19e of the separation claw 19 and the portions on both sides thereof, but the holding strength of the separation claw 19 is unstable. Accordingly, the contact pressure becomes unstable, and the transfer sheet material may not be able to be separated from the peripheral surface of the photosensitive drum 16.

Further, since the housing 18a has a claw fitting portion 18b protruding downward for holding the separation claw 19, the claw is formed while the transfer sheet material is being conveyed toward the right fixing portion in the drawing. There is a possibility of contact with the fitting portion 18b,
In this case, the unfixed toner image on the transfer sheet material may be damaged.

In view of the above problems, the present invention can prevent an increase in cost and an adverse electrical effect on the transfer operation, and can improve the holding strength of the sheet peeling member and the contact pressure between the sheet peeling member and the image carrier. It is an object of the present invention to provide an image forming apparatus capable of stabilizing an image with an appropriate size and preventing an unfixed toner image from being damaged.

[0013]

In order to solve the above-mentioned problems, an image forming apparatus according to the present invention comprises: On the downstream side, below the cleaning device for removing the toner remaining on the image carrier after the transfer, a belt-shaped sheet peeling member having a predetermined width is provided, and the sheet peeling member is provided with the image bearing member. A plurality of triangular peeling protrusions are formed on the body side at intervals in the length direction, and the side opposite to the image carrier side forms a stationary portion forming the upper side of the transfer path of the transfer sheet material. In this configuration, the transfer sheet material adhered to the peripheral surface of the image carrier is peeled off by being always in contact with the distal end portion of the peeling projection and the peripheral surface of the image carrier. .

According to the image forming apparatus having such a configuration,
Since a plurality of triangular peeling protrusions are formed at intervals in the length direction on the side of the sheet peeling member on the image carrier side,
The tip of the peeling projection always contacts the peripheral surface of the image carrier,
The transfer sheet material adhered to the peripheral surface of the image carrier can enter the inside of the transfer sheet material and be peeled off.

The side of the sheet peeling member opposite to the image carrier side can be adhered to the stationary portion with a large area, and since no cutting is required, the holding strength of the sheet peeling member and the sheet peeling strength can be improved. The contact pressure between the peeling projection of the member and the image carrier can be stabilized at an appropriate level. Further, the adjustment of the detachable adhesion position of the sheet peeling member to the stationary portion facilitates fine adjustment of the contact pressure between the peeling protrusion and the image carrier.

Further, since there is no convex portion in the bonding portion of the sheet peeling member, it is possible to prevent the unfixed toner image on the transfer sheet material from being damaged. Further, since an electric component such as a separation charger is not used, it is possible to prevent an increase in cost and an adverse influence on the transfer operation.

[0017]

Embodiments of the present invention will be specifically described below with reference to the drawings. 1 to 4
FIG. 1 is a diagram referred to for describing an embodiment of an image forming apparatus according to the present invention.

In the image forming apparatus shown in FIG.
Denotes a photosensitive member (image carrier), and reference numeral 2 denotes a corona charger. Reference numeral 3 denotes an exposure device that irradiates a laser beam or light of an LED (light emitting diode) to charge the surface of the photoconductor 1 uniformly charged by the corona charger 2 between the positive and negative electrodes. The conversion forms an electrostatic latent image on the surface.

Reference numeral 4 denotes a developing device. The toner is electrostatically attached to an electrostatic latent image formed on the surface of the photoconductor 1 by carrying toner on the surface, and the toner is applied to the surface of the photoconductor 1. An image is formed. Reference numeral 5 denotes a pair of registration rollers. The front end of the transfer sheet A (transfer sheet material) is made to stand by at a predetermined position, and the registration roller 5 starts rotating in accordance with the timing of forming a toner image. The sheet A is transported. Reference numeral 7 denotes a transfer roller, and the toner image formed on the surface of the photoconductor 1 is transferred onto the transfer paper A by the electric operation of the transfer roller 7.

Reference numeral 9 denotes a cleaning device.
A cleaning operation for removing toner remaining on the surface of the photoconductor 1 after transfer by the transfer roller 7 is performed. Reference numeral 9a denotes a cleaning blade, and reference numeral 9b denotes a polishing roller, which is configured to convey toner collected inside the cleaning device 9 to a toner discharge unit (not shown) by a screw conveyor 9c. Reference numeral 10 denotes a fixing roller, and reference numeral 11 denotes a conveyance guide for the transfer sheet A.

As shown in FIG. 2, at the bottom of the cleaning device 9, a sheet peeling member 8 made of a plastic sheet of polyester or the like (other kinds of plastics may be used) is detachably adhered. Have been. The sheet peeling member 8 extends along the axial direction of the photoconductor 1,
As shown in FIG. 3, it is formed in a belt shape having a predetermined width W. On the side of the photoconductor 1 (the right side in the figure), five triangular peeling projections 8a (other numbers may be formed) are formed at intervals in the longitudinal direction. The opening angle α of the tip of the projection 8a is set to 75 ° or more.

As shown in FIG. 4, the side of the sheet peeling member 8 opposite to the photoreceptor 1 (left side in the figure) is detachably adhered to a toner drop prevention sheet 13 via a double-sided adhesive tape 12. The side of the toner fall prevention sheet 13 opposite to the photoconductor 1 is detachably adhered to the bottom of the cleaning device 9 via a double-sided adhesive tape 14.

As described above, the sheet peeling member 8 is adhered to the bottom of the cleaning device 9 via the double-sided adhesive tape 12, the toner drop prevention sheet 13 and the double-sided adhesive tape 14, so that the tip of the peeling projection 8a is formed. It comes into sliding contact with the peripheral surface of the photoconductor 1. And at this time, as shown in FIG.
The angle θ between the tangent line L1 at the transfer portion where the photoconductor 1 contacts the transfer roller 7 and the straight line L2 connecting the contact position between the photoconductor 1 and the tip of the peeling projection 8a and the transfer portion is 3
It is set to 0 ° or more.

In the image forming apparatus having such a configuration, even if the transfer paper A tries to rotate together with the photoreceptor 1 without being separated from the peripheral surface of the photoreceptor 1 after the transfer, the leading end of the transfer paper A is a sheet. The transfer paper A that has been peeled off by the peeling projection 8a of the peeling member 8 and dropped from the peripheral surface of the photoconductor 1 can be guided by the transport guide 11 and transported toward the fixing roller 10.

That is, according to such an image forming apparatus, a plurality of triangular peeling projections 8a are formed on the side of the sheet peeling member 8 on the photoconductor 1 side at intervals in the length direction. The tip of the peeling projection 8a is always in contact with the peripheral surface of the photoreceptor 1, so that it can enter the inside of the transfer paper A adhered to the peripheral surface of the photoreceptor 1 and peel it off.

The side of the sheet peeling member 8 opposite to the photoreceptor 1 can be adhered to the bottom of the cleaning device 9 with a large area, and no cutting or the like is required. The holding strength and the contact pressure between the peeling projection 8a of the sheet peeling member 8 and the photoconductor 1 can be stabilized with an appropriate magnitude. Further, by adjusting the position where the sheet peeling member 8 can be detachably attached to the bottom of the cleaning device 9, fine adjustment of the contact pressure between the peeling projection 8a and the photoconductor 1 becomes easy.

Further, since there is no convex portion in the adhesive portion of the sheet peeling member 8, it is possible to prevent the unfixed toner image on the transfer paper A from being damaged. Further, since an electric component such as a separation charger is not used, it is possible to prevent an increase in cost and an adverse influence on the transfer operation.

Further, since the area of the sheet peeling member 8 can be increased, the discharge of static electricity becomes easy, and
Toner can be reduced. In addition, a tangent line L1 at a transfer portion where the photoconductor 1 and the transfer roller 7 are in contact with each other.
And the angle θ between the contact position between the photosensitive member 1 and the tip of the peeling projection 8a and the straight line L2 connecting the transfer portion is set to 30 ° or more, so that the transfer paper A is transferred to the photosensitive member 1. The transfer paper A is separated from the circumferential surface of the
It is possible to prevent the image forming apparatus from becoming inoperable due to being caught in the apparatus without being separated by a.

The peeling projection 8a of the sheet peeling member 8
Is set at 75 ° or more, so that the punching die of the sheet peeling member 8 is not an expensive separation die assembled separately into the peeling protrusion 8a and the other main body. It can be inexpensive whole integrated type. Further, since there is no convex portion in the bonding portion of the sheet peeling member 8, it is possible to prevent the unfixed toner image on the transfer paper A from being damaged by the convex portion.

In the above-described embodiment, the sheet peeling member 8 is adhered to the bottom of the cleaning device 9 via the double-sided adhesive tape 12, the toner drop prevention sheet 13, and the double-sided adhesive tape 14. Instead of using the sheet 13 and the double-sided adhesive tape 14, only the sheet peeling member 8 may be bonded to the bottom of the cleaning device 9 via the double-sided adhesive tape 12. In this case, the sheet peeling member 8 can be configured to also have the function of the toner drop prevention sheet 13.

Further, in the above-described embodiment, when the transfer protrusion A is pressed by the transfer paper A when the transfer paper A is separated from the photoreceptor 1 by the peel protrusion 8a, the peel protrusion 8a is deformed. In this case, the deformed portion comes into contact with the portion facing the peeling protrusion 8a on the photosensitive member 1 side of the toner fall prevention sheet 13, and the toner fall prevention sheet 13 receives the deformed portion of the peeling protrusion 8a, thereby separating the toner. Extreme deformation of the projection 8a can be avoided, and the transfer paper A can be moved in the direction in which the transfer paper A is separated from the photoconductor 1 by receiving the pressure from the transfer paper A.
Even when the toner drop prevention sheet 13 is not used,
A similar effect can be obtained by arranging the deformed portion of the peeling projection 8a as described above so as to be received at the bottom of the cleaning device 9.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various other modifications are possible based on the technical idea of the present invention. Can be changed.

[0033]

As described above, according to the image forming apparatus of the present invention, a plurality of triangular peeling projections are formed on the side of the sheet peeling member on the image carrier side at intervals in the length direction. Therefore, the tip of the peeling projection is always in contact with the peripheral surface of the image carrier, so that it can enter the inside of the transfer sheet material adhered to the peripheral surface of the image carrier and peel it.

The side of the sheet peeling member opposite to the image carrier side can be adhered to the stationary portion with a large area, and since no cutting or the like is required, the holding strength of the sheet peeling member and the sheet peeling strength can be improved. The contact pressure between the peeling projection of the member and the image carrier can be stabilized at an appropriate level. Further, by adjusting the attachment position where the sheet peeling member can be detachably attached to the stationary portion, fine adjustment of the contact pressure between the peeling protrusion and the image carrier becomes easy.

Further, since there is no projection at the bonding portion of the sheet peeling member, it is possible to prevent the unfixed toner image on the transfer sheet material from being damaged. Further, since an electric component such as a separation charger is not used, it is possible to prevent an increase in cost and an adverse influence on the transfer operation.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the image forming apparatus of FIG.

FIG. 3 is a bottom view of the sheet peeling member 8 of FIGS.

FIG. 4 is an exploded cross-sectional view of the sheet peeling member 8 taken along line CC of FIG.

FIG. 5 shows a separation claw 1 between a housing 18a of an image forming unit 18 and a photosensitive drum 16 of a conventional image forming apparatus.
FIG. 9 is a perspective view showing 9.

FIG. 6 is an enlarged perspective view showing the separation claw 19 of FIG.

FIG. 7 is a sectional view taken along line AA in the image forming apparatus of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 Corona charger 3 Exposure device 4 Developing device 5 Registration roller 7 Transfer roller 8 Sheet peeling member 8a Peeling protrusion 9 Cleaning device 9a Cleaning blade 9b Polishing roller 9c Screw conveyor 10 Fixing roller 11 Transport guide 12 Double-sided adhesive tape 13 Toner drop prevention sheet 14 Double-sided adhesive tape 16 Photoreceptor drum 18 Image forming unit 18a Housing 18b Claw fitting portion 19 Separating claw 19a Tip portion 19b Rear end portion 19c Opening 19d Cut 19e Pressing piece 28 Transfer roller 30 Separating portion A Transfer paper

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H134 GA01 GB02 HD00 KF01 KF06 KG04 KH07 KH10 2H200 FA06 GA23 GA33 GA34 GB12 HB03 JA02 JB12 KA02 KA14 KA25 MA02 3F053 AA20 AA21 AA22 LA02 LA07 LB03

Claims (6)

[Claims] A cleaning device that removes toner remaining on the image carrier after the transfer at a position downstream of a transfer section where the toner image on the image carrier is transferred to the transfer sheet material in a conveying direction of the transfer sheet material. Below, a stripping member formed in a strip shape having a predetermined width is provided, and the stripping member has a triangular stripping protrusion at a side portion on the image carrier side in a length direction. A plurality of side portions opposite to the image carrier side are adhered to a stationary portion forming an upper side of a transfer path of the transfer sheet material, and a tip portion of the peeling protrusion is always on a peripheral surface of the image carrier. An image forming apparatus, wherein the transfer sheet material adhered to the peripheral surface of the image carrier is peeled off by contact. 2. An opening angle of a leading end of the peeling projection is 75 °.
The image forming apparatus according to claim 1, wherein: 3. An angle between a tangent line of the image carrier at the transfer portion and a straight line connecting the contact position between the image carrier and the tip of the peeling protrusion and the transfer portion is 30 ° or more. The image forming apparatus according to claim 1. 4. The image forming apparatus according to claim 1, wherein the sheet peeling member is detachably adhered to a bottom of the cleaning device by a double-sided adhesive tape. 5. The image forming apparatus according to claim 1, wherein the sheet peeling member also functions as a toner fall prevention sheet that receives toner leaking and falling from the cleaning device. 6. The image forming apparatus according to claim 1, wherein the sheet peeling member is formed of a plastic sheet.