JPH0423761A - Sheet separating system - Google Patents

Abstract

PURPOSE:To easily and certainly peel and separate a sheet wound on a drum with high reliability by providing a suction/separation means which sucks a sheet by suction when it is pressed into contact with the sheet, and separates the sheet from the drum when it is separated from the drum. CONSTITUTION:In the state where a suction/separation means 17 is pressed into contact with the carrying directional top end p-d side of a sheet P wound on a drum 12 to attract the sheet P by suction, the means 17 is separated from the drum 12, and thereby the sheet P is separated from the drum 12. As the sheet P thus can be separated without using the stiffness of the sheet P and the dead weight of the paper itself, the sheet P can be easily and certainly peeled and separated from the drum 12 even if the drum 12 has a large outer diameter, or the sheet P is carried on the drum 12. When the suction/separation means 17 is a roller consisting of an elastic member having a plurality of sucker-like recessed parts formed on the outer circumference, the air pressure in the recessed parts in reduced when the means 17 is pressed into contact with the sheet P, and the sheet P is sucked by the atmospheric difference with the outside air.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a paper separation mechanism for separating paper wrapped around a drum disposed in an image forming section of an image forming apparatus such as a copying machine or a printer. In particular, the present invention relates to a paper separation mechanism suitable for separating paper from a drum having a large outer diameter.

[Conventional technology]

As a conventional paper separation mechanism from a drum, for example, a fourth
A highly reliable separation mechanism that uses AC static elimination separation and separation claws as shown in the figure is known.

That is, in an electrophotographic copying machine or printer, this paper separation mechanism transfers an image onto a paper P using a transfer corotron 1, and then removes static electricity using an alternating current corona using a separation corotron 2, and transfers the paper P to a photoreceptor drum 3. The electrostatic adsorption force is reduced, the paper is separated using its stiffness and its own weight, and the sharp tip 4a of the separating claw 4 is slid into contact with the photosensitive drum 3 rotating in the direction of the arrow in FIG. Then, the leading edge of the paper P is forcibly peeled off from the photoreceptor tram 3 and separated.

[Problem to be solved by the invention]

However, in the case of such a paper separation mechanism that uses AC static electricity removal separation and a separation claw in combination, the paper is separated from the photoreceptor drum by utilizing the stiffness of the paper and the paper's own weight. For example, when the outer diameter of the photosensitive drum is large, the outer circumferential surface of the drum approaches a flat state, so the method of separating the sheets based on the stiffness of the sheets becomes less reliable.

In addition, in the case of a separation method that uses the paper's own weight,
The downward conveyance shown in Figure 4 (conveying the paper to the bottom of the photoconductor drum 3) is fine, but in the case of the downward conveyance type that conveys the paper to the top of the photoconductor drum, the separation side of the paper is fine. This causes inconvenience because the weight is applied in the opposite direction.

In recent years, the demand for color copiers, color printers, etc. has been increasing, and when a drum color overlapping one-shot transfer method is used with such equipment, the drum manager has to adjust the transport direction of the largest size paper to be used. The minimum length is required.

Therefore, since the photoreceptor drum has a large outer diameter, in the case of a separation mechanism that uses both AC static electricity removal and separation and separation claws, the reliability in separation of sheets decreases for the reasons described above.

Therefore, although there are other types of paper 1I11 mechanisms, such as an electrostatic adsorption induction separation method and a separation method using air pressure, the durability of the guide member is a problem in the former case.

In the latter case, there are problems such as noise caused by the vacuum suction and an increase in the size of the device, and both problems result in high costs.

This invention was made in view of the above problems,
Paper wrapped around a drum such as a photosensitive drum with a large outer diameter can be easily and reliably peeled off and separated even if the paper is transported on top of the drum. The purpose is to do so.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a paper separation mechanism that separates paper wrapped around a drum, which is provided so as to be able to press against and separate from the leading edge of the paper wrapped around the drum in the conveyance direction. The apparatus is provided with an adsorption/separation means that adsorbs the paper by adsorption force when the paper is removed from the drum, and separates the adsorbed paper from the drum when the paper is separated from the drum.

As the adsorption/separation means, a roller made of an elastic member having a plurality of suction cup-like depressions formed on the outer circumferential surface, a roller or a film material having an adhesive surface capable of adsorbing the paper on the surface can be used. .

[For production]

According to the paper separation mechanism configured in this way, if the suction separation means is brought into pressure contact with the leading end side of the paper wrapped around the drum in the conveyance direction and the paper is attracted by suction force and then separated from the drum, the paper can be separated from the drum. Since the paper can be separated without using the stiffness of the paper or the weight of the paper white body, it is possible to separate the paper without using the stiffness of the paper or the weight of the paper white body. Even so,
It can be easily and reliably peeled off and separated from the drum.

If the adsorption/separation means is a roller made of an elastic member with a plurality of suction cup-like depressions formed on its outer circumferential surface, when it is brought into pressure contact with the paper, the air pressure in the depressions decreases and the outside air The paper is attracted by the pressure difference between the paper and the paper.

Further, when the suction separation means is a roller or a film material having an adhesive surface capable of adsorbing the paper, when the adhesive surface is brought into pressure contact with the paper, the paper can be adsorbed by its adhesiveness.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example in which a paper separation mechanism according to the present invention is provided close to a photosensitive drum of a copying machine, and FIG. 2 is a schematic diagram showing an example in which a paper separation mechanism according to the present invention is provided in close proximity to a photosensitive drum of a copying machine, and FIG. FIG. 3 is a perspective view showing an example of a separation roller.

The paper separation mechanism 10 shown in FIG. 1 is a mechanism for separating the paper P wrapped around the photoreceptor drum 12 from the drum, and the paper separation mechanism 10 shown in FIG. ) is provided so that it can be pressed against and separated from the position shown by the solid line and the position shown by the imaginary line on the front end Pa side of the paper P. A separation roller 17 is provided as an adsorption/separation means for separating the adsorbed paper P from the photosensitive drum 12 when the paper P is separated.

The photosensitive drum 12 rotates in the direction of arrow B in FIG. 1, and the transfer corotron 13 is on the left side of the surrounding separation roller 17 in FIG. 1, and the photosensitive drum 12 is on the right side. Cleaners 14 for cleaning the surface are arranged, and fur brushes 15 of the cleaners 14 touch the photosensitive drum 12.
rotates in the direction of arrow C while in contact with the surface of

As shown in FIG. 2, the separation roller 17 is a roller made of an elastic member, such as rubber, and has a plurality of sucker-shaped depressions 20 formed on its outer peripheral surface. The swing lever 1 is rotatably attached to one end.
A return spring 21 is attached to the other end of the solenoid 16 to apply a biasing force in a direction opposite to the movable shaft of the solenoid 16 and the operating direction of the solenoid 16 (the rightward suction direction in FIG. 1), and the solenoid 16 is turned on. When in the off state, the separation roller 17 is in pressure contact with the surface of the photosensitive drum 12 as shown by the solid line in FIG. 1, and when it is in the off state, it is separated to the position shown by the imaginary line.

Further, a separation claw 19 is provided close to the separation roller 17,
The paper P adsorbed to the surface of the separation roller 17 by the separation claw 19 is brought into contact with the separation roller 17 from the tip Pa side.
This makes it possible to peel it off.

In this copying machine, when a sheet of paper P is conveyed in the direction of arrow A in FIG. When the tip Pa reaches the position of the separation roller 17 after being conveyed in the direction indicated by B, the photoreceptor drum 12
The separation roller 17 that has been away from the paper P
When it comes into contact with the top a, it descends and makes pressure contact.

Therefore, the separation roller 17 rotates along with the photoreceptor drum 12 due to frictional force, and the outer periphery of the separation roller 17 has a suction cup-like depression 20 that attracts the paper as described above.
(Fig. 2), the air pressure in the recess 20 becomes low during pressure contact, and the paper P is sucked due to the pressure difference with the outside air, causing the paper P to separate from the photoreceptor drum 12. It wraps around the separation roller 17 side.

Then, the separation roller 17 continues to rotate counterclockwise in FIG. As is clear from the above, since it is formed to have a much smaller diameter than the outer diameter of the photoreceptor drum 12, the leading edge Pa is separated from the outer peripheral surface of the roller due to the stiffness of the paper itself, and the leading edge Pa is When the sheet comes into contact with the separating claw 17, the stiffness of the sheet itself acts further on the peeling side, so that the image surface is easily peeled off without being rubbed, and the sheet is conveyed toward the fixing section.

FIG. 3 is a schematic diagram showing an example of a different paper separation mechanism using a film material with an adhesive surface for the suction separation means, and parts corresponding to those in FIG. 1 are given the same reference numerals.

This paper separation mechanism 30 has a surface 31 as an adsorption separation means.
A film material 31 with an adhesive surface capable of adsorbing paper P to a
The film material 31 is disposed between the photosensitive drum 12 and the separation roller 17.

In this paper separation mechanism 30, when the paper P is conveyed in the direction of arrow A in FIG. 3 and its leading edge Pa reaches below the separation roller 17, the separation roller 17
moves downward from the position shown by the imaginary line to the position shown by the solid line, and the separating roller 17 comes into pressure contact with the paper P on the photosensitive drum 12 via the film material 31.

At this time, since the surface 31a of the film material 31 on the side (lower surface side) facing the photoreceptor drum 12 is an adhesive surface,
The paper P is attracted to the adhesive surface and separated from the photoreceptor drum 12.

Therefore, when the separating roller 17 is raised to the raised position shown by the imaginary line in FIG. 3 and released from the photosensitive drum 12 again, the paper P adsorbed to the surface (adhesive surface) 31a of the separating roller 17 is removed from the embodiment shown in FIG. Similarly, the film material 3 is separated as shown in FIG.
It is peeled off from the surface 31a of 1.

In this embodiment, both ends of the film material 31 are wound up by the winding drums 32 and 33, respectively, so that the film material 31 can be moved in the direction of arrow E in FIG. Before the second sheet of paper reaches the separation roller 17, the adhesive surface of the film material 31 used to attract P is moved by winding the film material 31 in the direction of arrow E, and becomes an unused portion again. and prepare for the next adsorption.

Note that the adsorption/separation means may be a roller having an adhesive surface capable of adsorbing the paper on one surface.

An embodiment in which the present invention is applied to a paper separation mechanism that separates paper wrapped around a photoreceptor drum of a copying machine has been described above. The present invention can be similarly applied to a paper separation mechanism of a drum or a paper separation mechanism of a drum of a printer other than a copying machine.

〔Effect of the invention〕

As explained above, according to the present invention, even if the outer diameter of the drum is large or the paper is transported on top of the drum, the paper wrapped around the drum can be easily and reliably removed. It can be peeled off and separated.

Further, when a roller made of an elastic member having a plurality of suction cup-like depressions formed on the outer circumferential surface is used as the suction separation means, a separation mechanism with a simple structure and high durability can be obtained.

Further, when a roller or a film material having an adhesive surface capable of adsorbing paper on one surface is used as the suction/separation means, it is possible to provide a separation mechanism that can easily separate the paper at low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example in which a paper separation mechanism according to the present invention is provided close to a photoreceptor drum of a copying machine, and FIG. A perspective view showing an example of a separation roller, Fig. 3 is a schematic diagram showing an example of a different paper separation mechanism using a film material with an adhesive surface for the adsorption/separation means, and Fig. 4 shows a conventional AC static elimination separation and separation claw. FIG. 2 is a schematic diagram illustrating an example of a paper separation mechanism that uses the paper separation mechanism. 10.30...Paper separation mechanism 12...Photoconductor tram 13...Transfer corotron 14...Cleaner 17...Separation roller (adsorption separation means) 2o...Indentation 31...Film material ( Adsorption separation means) 31a...
・Surface P...Paper Pa...Top phrase Miomi Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A paper separating mechanism for separating paper wrapped around a drum, which is provided so as to be able to press against and separate from the leading edge of the paper wrapped around the drum in the conveying direction, and when pressed against the paper, 1. A paper separation mechanism comprising an adsorption/separation means that adsorbs a paper by suction force and separates the adsorbed paper from the drum when the paper is separated from the drum. 2. The paper separation mechanism according to claim 1, wherein the suction separation means is a roller made of an elastic member having a plurality of suction cup-like depressions formed on its outer peripheral surface. 3. The paper separation mechanism according to claim 1, wherein the adsorption/separation means is a roller or a film material having an adhesive surface capable of adsorbing the paper.