JPS59113469A - Paper stripping device - Google Patents

Abstract

PURPOSE:To avoid floating of paper by making a stripping roller with a conductive member to earth it to the device main body and covering the surface of the stripping roller with an insulating layer together with a roller part having a diameter larger than the outer diameter of the device main body with a space secured in the axial direction. CONSTITUTION:A stripping roller 10 of a paper stripping device is made of a conductive member, and the surface of the roller 10 is covered with an insulating layer 16. The roller 10 is earthed to the main body of a copying machine and furthermore contains plural roller parts 17a having diameters larger than the outer diameter of the main body provided equidistantly in the axial direction. The part 17a is made of a member having a large frictional coefficient such as rubber, etc., and the outer diameter of the part 17a is slightly larger than that of the roller 10. In such a constitution, the paper is attracted toward the roller 10 after stripping. This prevents floating of the paper and ensures good copying.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a paper separating device for separating a sheet of paper from a photoreceptor after transferring a toner image formed on a photoreceptor onto a sheet of paper, for example.

<Prior art> An electrophotographic copying machine forms an image corresponding to a document on paper by arranging charging, exposure, development, transfer, neutralization, and cleaning processes around a drum-shaped photoreceptor. are doing. In this apparatus, when transferring a toner image formed on a photoreceptor through a development process to a transfer material, which is paper, an electrostatic transfer method is widely used. In this electrostatic transfer, for example, a transfer material that is sent as appropriate is brought into close contact with a photoreceptor,
A corona discharge having a polarity opposite to that of the toner is generated from the back side of the transfer material, and the toner is electrostatically transferred to the transfer material side. In this case, a Coulomb force acts on the transfer material charged by the corona discharge so that it is attracted to the photoreceptor. Therefore, since the transfer material is attracted to the photoreceptor and carried to a charge removal and cleaning process, a means is provided to separate the transfer material from the photoreceptor after transfer.

An example of a transfer material separating means is shown in FIG. In the figure, / is provided at the post-transfer position and the photoreceptor (
3 is a separation roller rotated at the same circumferential speed as the separation roller (not shown); 3 is a separation auxiliary roller rotatably provided in pressure contact with the separation roller; 3 is a transfer material that is in close contact with one side edge of the photoreceptor in the transfer area Separate one end of the roller from the photoreceptor and
, - is a separation guide belt that guides between. According to the separating mechanism configured as described above, one end of the transfer material is separated from the photoreceptor by the belt 3, and is guided between the rollers/1 and 2.
It is held between rollers/1.2 and separated from the photoreceptor. Such a separation mechanism has advantages such as a simple structure, low cost, and reliable separation. However, as shown in FIG.

If the roller/1.2 is used to clamp the transfer material by pressing it against the photoreceptor, the roller/1.2 can only clamp the transfer material with an area that is equivalent to a line contact, and most of the transfer material is in close contact with the photoreceptor. Therefore, when the photoreceptor is being conveyed along the rotation of the photoreceptor, it may deviate diagonally from the predetermined conveyance direction. In other words, if the transfer material is held between rollers /2.2, the force necessary for separation can be obtained, but it is not possible to obtain the force to prevent deviation from the predetermined conveyance direction.

Therefore, in order to prevent transfer defects and paper jams caused by diagonal feeding of the transfer material, air is blown between the separation roller and the transfer material that has begun to separate to strengthen the separation force. Measures such as these were taken.

Furthermore, even when the transfer material is being conveyed after the separation has been reliably performed, the transfer material may be lifted off the fixed path due to its own stiffness or the like. This also causes skew feeding and wrinkles of the transfer material after fixing. Furthermore, due to the lifting of the transfer material, the transfer material may rise or slip off the transfer process, resulting in transfer defects. As a countermeasure to this problem, the separated transfer material is sucked into the conveyance path using means such as air suction to prevent the transfer material from lifting up.

As mentioned above, in order to reliably separate the transfer material and transport it stably without shifting the transport direction, a large amount of equipment such as air blowing means and air suction means is required, and the structure and control are complicated. Therefore, the separation device itself had the disadvantage of being expensive.

<Object of the Invention> In view of the conventional drawbacks, the present invention provides an apparatus for separating sheets, which includes a separating roller and an auxiliary means for separating.
It is an object of the present invention to perform reliable and stable separation by causing the separation roller to suck the paper with a simple configuration without using means such as air suction.

<Example> An example of the transfer material separating device of the present invention is shown in FIG. On the right side of the figure, reference numeral 5 denotes a photoreceptor that is rotated in the direction of the arrow, and O is an electrostatic charge that transfers the toner image on the photoreceptor j to a paper sheet, which is a transfer material, that is guided along a guide via a conveyance roller 7. A corona discharger for transferring, 10 a separation roller provided at the rear of the transfer process, // a separation roller / θ a separation guide part /-
? A separation guide tape /3 is used to guide the paper sheet to the separation roller 10, which is brought into close contact with the photoreceptor j during the transfer process. The separation guide section 7
．． 2 is formed to match the circumferential surface of the separation roller 10, and is configured to press and hold one side end of the paper 2 guided by the separation guide tape/3 with the separation roller 10. However, in the present invention, a pressure roller may be provided as shown in FIG. 7 without providing the separation guide portions /, 2, and the separation guide tape /3 is pressed against the separation roller /θ, and the paper sheet is attached to the tape. It is also possible to have a structure in which they are separated by being sandwiched between /3 and rollers 10. That is, the separation roller 10 and the separation guide section 7
．． The present invention can be applied to a configuration in which other separation auxiliary means such as 2 or a separation guide tape 73 are provided and the sheets 2 are separated by the cooperation of these means.

As shown in FIG. 1, the separation guide 7.2 that comes into pressure contact with the separation roller 10 is attached to the tip of the separation guide lever //, and is formed in a curved shape along a part of the outer circumference of the roller 10. has been done. Since the separation guide/-2 repeatedly experiences friction when the paper 2 is conveyed or comes into contact with the separation roller 10, it is preferable to form it from a material with a low coefficient of friction. Further, the separation guide 7.2 is suitably made of a material that is more easily worn than the material of the separation roller 10, since the contact surface becomes more comfortable as the separation guide 7.2 repeatedly rubs against the separation roller 10.

Therefore, the separation guide 7.2 is made of a material with a low coefficient of friction, which is more likely to wear than the separation roller/θ (usually a rubber roller), which allows for a certain amount of wall thickness in consideration of minute wear, and which makes it easy to obtain the curvature of the sliding surface. Fluororesin or the like is suitable because it is easy to process integrally with the lever. In order to bring the separation guide 7.2 into pressure contact with the separation roller 10, a lever // is rotatably provided around a shaft /, and is biased clockwise in the figure by a spring /, s. .

Therefore, the separating guide 7.2 is pressed against the separating roller lθ.

The present invention provides a paper 2 separated and guided by the separation roller 10.
In order to adsorb the
is formed of a conductive material, and the surface of this roller is covered with an insulating layer/
Covered by Z. The separation roller 10 is electrically grounded to the main body of the copying machine. Furthermore, the seventh separation roller 10
As shown in the perspective view of the figure, the roller part /7a formed of the same material as the roller part /7 of the part where one side end of the paper 2 is held between the separation guide guide /2, and the roller part /7a are arranged equally in the axial direction. Multiple pieces are provided at intervals. The roller portion/7a is made of a member having a large friction coefficient, such as rubber.

The outer diameter of this roller portion/7a is slightly larger than the outer diameter of the roller body provided with the insulating layer/Z, and is stepped.

In addition, the code /♂ in the figure is the guide plate /♂ for paper after separation.
2 to the next fixing process.
0 is a conveyance auxiliary roller that is pressed against the roller/dot.

In the separation mechanism having the above-described structure, in an actual example of use, the photoreceptor 5 is configured to be relatively separable from the separation mechanism and the corona discharger Z. In other words, by separating photoreceptor j,
It becomes convenient to remove jams in the paper 2, and the separation mechanism can be easily assembled.

The operation of the separation mechanism configured as described above will be explained below. The paper sheet is conveyed via a conveyance roller 7 along a guide ♂ to a transfer process where it faces a photoreceptor 5 . This paper 2 is first guided at one end by a separation guide tape/3 before the transfer process, and then guided to the transfer process opposite to the corona discharger 2. The guided paper 2 is separated from the photoreceptor j by the separation guide tape 3 at its negative end, and the rest of the paper 2 is in close contact with the photoreceptor j, and the toner on the photoreceptor is transferred by the action of corona discharge. Ru.

The toner image is transferred onto the paper 2 as described above, and the paper after the transfer tries to be conveyed along the rotational direction of the photoreceptor j, but the negative end of the paper is not exposed to light by the separation guide tape /3. It is guided away from the body 5 and gradually separated from the - side end. Then, the paper 2 guided by the separation guide tape /3 is guided to the vicinity of the press-contact part between the separation roller /θ and the separation guide 7.2, and the tip thereof is connected to the roller 10.
and the guide/2. By sandwiching the paper 2 between the separation roller 10 and the separation guide 7.2,
This paper 2 obtains the force necessary to resist the adhesion force between the photoreceptor j and the paper 2, that is, the force necessary for separation and to prevent the paper from shifting from the predetermined conveyance direction.

At the same time, as shown in FIG. 3, the back side of the paper 2 is charged with, for example, ■ by the corona discharger O during the transfer process, and this charge causes the insulating layer/B to be sandwiched on the separation roller 10 side. θ charge is induced.

After the paper is separated by this induced e-charge, it is attracted toward the separation roller 10 by electrostatic force. Therefore, after the paper is separated, it is attracted to the separation roller 10, and the separation roller 10
Separation progresses as the material rotates, and is stably separated without being deviated from the predetermined conveyance direction, and lifting is also prevented. In this case, even if the separation roller 10 and the paper 2 are in close contact with each other, since the insulating layer/B is provided, the charges are not likely to be neutralized, and the adhesion force continues for a certain period of time, so that stable separation can be expected. Furthermore, the paper 2 is charged with the opposite polarity to the charge held by the toner 2/ on the photoreceptor 5, so that the toner is attracted to the paper 2 side and transfer is performed, but as a result, the charge on the paper 2 is completely neutralized. There is sufficient charge to induce a charge on roller 10 rather than adding up.

After separation, the paper is attracted to the separation roller 10, so that
The back surface thereof is pressed against a roller portion/7a made of rubber or the like which protrudes from the roller body provided with the insulating layer/B. At this time, paper 7
The adsorption force to the roller 10 is determined by the strength of the roller part/
It acts as a pressing force of the paper 2 against the paper 7a. This pressing force of the paper 2 against the roller portion/7a is transmitted to the paper 2 by the rotation of the separation roller 10, and is useful for improving the conveyance force after separation. In this way, the paper 2 is attracted to the separation roller side after separation, thereby preventing transfer defects due to lifting.
In addition, a pressure force applied to the roller m/7a due to suction acts, and a more reliable conveyance force is applied, so that skew feeding and conveyance defects do not occur.

Also, as shown in Figure 3, there is an insulating layer on the surface of the conductive guide plate/2! If - is provided, the separated paper 2
The particles are further attracted to the guide plate, making transportation after separation more stable. The separated paper sheet is guided along the guide plate /2, and the fixing roller 23. The toner is guided to J41 and the toner on the upper surface is fixed.

FIG. 5 is a diagram showing another embodiment of the present invention.

In this example, instead of forming an insulating layer on the rotating separation roller itself and adsorbing the paper 2, the paper 2 after separation is adsorbed by the guide plate/2. As shown in the figure, the roller parts /7 and /7a of the separation roller 100 are provided at equal intervals in the direction of the axis 10/, and the roller parts /7 and /7a are provided at equal intervals in the direction of the axis 10/.
Extend guide plate/2 between 7a and attach suction part-7
5 will be provided. This suction part 26 is a roller part/7 in FIG.
It is formed to have the same outer peripheral shape as the roller body between them, and is integrated with the guide plate/2. Adsorption part-7,5
The surfaces of the guide plate/2 are both covered with an insulating layer and are formed smaller than the outer diameter of the roller portion/7a.

Further, like the guide plate 72, the suction portion 26 is electrically conductive and is grounded to the main body of the apparatus.

Also in the configuration shown in FIG. 5, the paper 2 after separation is attracted to the suction section -7j, and the separation roller/θ0 roller section/
7a. Therefore, the paper is separated by the separation roller 10.
Conveying force is applied at the roller part/7a due to the rotation of 0,
A fixing roller, 23. ．． It is transported to the 2nd station.

Here, the paper tray is attached to the suction unit, 2j and the guide plate/
Since it is necessary to convey the paper by sliding it, a smooth tape with a low coefficient of friction, such as a fluororesin tape, may be attached or coated on the insulating layer to improve the sliding of the paper. Further, the guide plate/2 has ribs 21. It is suitable if this occurs.

According to this embodiment, separation of transfer material in a copying machine has been described, but this is not limited to copying machines, but applies to any device that separates charged paper by cooperation with a separation roller and a separation auxiliary means. It is clear that the invention can be put into practice.

<Effects of the Invention> According to the paper separation device of the present invention, in a device configured to sandwich a paper between a separation roller and a separation auxiliary means that is in pressure contact with the roller, and to separate the paper by the cooperation of these rollers, the separation roller is made of a conductive material and grounded to the device body,
The surface of the roller is covered with an insulating layer, and since the roller portion, which is larger than the outer diameter of the roller body, is spaced apart in the axial direction, the electric charge of the charged paper can cause the paper to move backward toward the separating roller. By inducing polar charges, the paper after separation is attracted to the roller side, which prevents the paper from lifting up, resulting in good transfer, and provides conveying force to the paper while it is attracted to the rollers. Therefore, stable and reliable transport can be expected without deviation from the predetermined transport direction even during transport after separation.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of a conventional separation mechanism, FIG. 1 is a perspective view showing an example of a separating device according to the present invention, FIG. This figure is a perspective view of a separation roller of the present invention, and FIG. 5 is a perspective view showing another embodiment of the present invention. , 5: Photoreceptor, 2: Corona discharger, 2: Paper, 10
(100): Separation roller, //: Separation guide lever, /-7=Separation guide, /3: Separation guide tape, /z: Insulating layer, /7. /7a: roller part,
/2 guide plate, roller: suction part.

Claims (1)

[Claims] 1. In a separating device having a structure in which a charged paper is held between a separation roller and a separation auxiliary means, and the paper is separated from a member that is in close contact with the paper, the separation roller is formed of a conductive member and is grounded to the main body of the device. At the same time, a separation roller whose surface is covered with an insulating layer is provided, and a roller section for applying a conveying force to the paper having a diameter larger than the outer diameter of the separation roller main body.
A paper separation device characterized in that a plurality of separation rollers are provided at intervals in the axial direction.