JPH052993B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to, for example, a paper separation device for separating a transfer material from the photoreceptor after transferring a toner image formed on the photoreceptor.

<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, an electrostatic transfer method is widely used when transferring a toner image formed on a photoreceptor through a development process to a transfer material, which is paper. This electrostatic transfer is
For example, a transfer material that is sent as appropriate is brought into close contact with a photoreceptor, and a corona discharge having a polarity opposite to that of the toner is generated from the back side of the transfer material to electrostatically transfer the toner to the transfer material. 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 step, 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, reference numeral 1 indicates a separation roller that is provided at a post-transfer position and rotates at the same peripheral speed as a photoreceptor (not shown); 2 is a separation auxiliary roller that is in pressure contact with the separation roller and is rotatably provided; and 3 A separation guide belt is brought into close contact with one side edge of the photoreceptor in the transfer area and guides one side edge of the transfer material 4 to between the rollers 1 and 2 while separating it from the photoreceptor. According to the separation mechanism configured as described above, one end of the transfer material 4 is separated from the photoreceptor by the belt 3, and is guided between the rollers 1 and 2, and the photoreceptor held between the rollers 1 and 2 is separated from the photoreceptor by the belt 3. more separated. Such a separation mechanism has advantages such as a simple structure, low cost, and reliable separation. However, as shown in FIG. 1, if the rollers 1 and 2 are pressed against each other to sandwich the transfer material 4, the rollers 1 and 2 can only sandwich the transfer material 4 with an area that is equivalent to a line contact. Since most of the transfer material 4 is in close contact with the photoreceptor, it sometimes deviates obliquely from a predetermined transport direction when it tries to be transported along the rotation of the photoreceptor. In other words, rollers 1 and 2
Although it is possible to obtain the force necessary for separating the transfer material by holding the transfer material between them, it is not possible to obtain the force necessary to prevent the transfer material from being deviated from the predetermined conveyance direction.

Therefore, in order to prevent transfer defects and paper jams caused by diagonal feeding of the transfer material 4, air is blown between the transfer material 4 that has begun to separate and the separation roller 1 to increase the separation force. Measures were taken to strengthen the situation.

Furthermore, even when the transfer material 4 is being conveyed after the separation has been reliably performed, the transfer material 4 may be lifted off the fixed path due to its own stiffness or the like. Therefore, it also causes skewed feeding and misalignment of the transfer material 4 after fixing.
Further, due to the lifting of the transfer material 4, the transfer material 4 may be lifted from the transfer process or shifted, resulting in a transfer defect. As a countermeasure to this problem, the separated transfer material 4 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, large-scale equipment such as air blowing means and air suction means is required, and the structure and control are difficult. This method has the disadvantage that it becomes complicated and the separation device itself becomes expensive.

<Object of the Invention> In view of the conventional drawbacks, the present invention provides a device for separating sheets that is equipped with a separation roller and an auxiliary means for separation, and has a simple structure without using means such as air suction. The purpose of this invention is to cause the separation roller to attract the paper to perform reliable and stable separation.

<Example> The transfer material separating device of the present invention has a configuration as shown in FIG. In the figure, 5 is a photoconductor that is rotated in the direction of the arrow, and 6 is an electrostatic transfer of the toner image on the photoconductor 5 onto paper 9, which is a transfer material, which is guided along a guide 8 through a conveyance roller 7. 10 is a separation roller provided at the rear of the transfer process; 11 is a separation roller 10 with a separation guide section 1;
A separation guide lever 13 is a separation guide tape for guiding the paper 9 to the separation roller 10, which is brought into close contact with the photoreceptor 5 during the transfer process.
The separation guide section 12 is formed to match the circumferential surface of the separation roller 10 and is configured to hold one side end of the paper 9 guided by the separation guide tape 13 in pressure contact with the separation roller 10. However, in the present invention, a pressure roller may be provided as shown in FIG. 1 without providing the separation guide section 12, and the separation guide tape 13 is further pressed against the separation roller 10 to separate the paper 9 between the tape 13 and the roller 10. It is also possible to have a structure in which the parts are separated by being held between them. The present invention can be applied to a configuration in which the separation roller 10 and other separation auxiliary means such as the separation guide section 12 or separation guide tape 13 are provided and the paper 9 is separated by the cooperation of these devices.

As shown in FIG. 2, the separation guide 12 that comes into pressure contact with the separation roller 10 is attached to the tip of the separation guide lever 11, and is formed in a curved shape along a part of the outer circumference of the roller 10. . The separation guide 12 is preferably formed of a material with a low coefficient of friction because it repeatedly experiences friction when the paper 9 is transported or when it comes into contact with the separation roller 10. Further, the separation guide 12 is preferably 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 roller 10 repeatedly rubs against the separation guide 12. Therefore, the separation guide 12 is made of a material with a low coefficient of friction, and is more likely to wear than the separation roller 10 (usually a rubber roller).The separation guide lever 11 can be made thicker to a certain extent in consideration of minute wear, and the curvature of the sliding surface can be easily obtained. From the fact that it is easy to process integrally with
Fluororesin etc. are suitable. This separation guide 12
In order to press the separation roller 10, lever 1 is pressed.
1 is rotatably provided around a shaft 14,
It is biased clockwise in the figure by a spring Y15. Therefore, the separation guide 12 is connected to the separation roller 1.
Pressed to 0.

In the present invention, in order to adsorb the paper 9 separated and guided by the separation roller 10, the separation roller 10 is formed of a conductive material as shown in FIG. 3, and the surface of this roller is covered with an insulating layer 16. It's on. The separation roller 10 is electrically grounded to the main body of the copying machine.

Further, reference numeral 17 in the figure is a conveyance roller that conveys the separated paper 9 along a guide plate 18 to the next fixing process, and 19 is a conveyance auxiliary roller that is in pressure contact with the roller 17.

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 6. That is, by separating the photoreceptor 5, it becomes convenient to remove jams in the paper 9, and the separation mechanism can be easily assembled.

The operation of the separation mechanism configured as described above will be explained below. The paper 9 is transported by the conveyance roller 7
The photoreceptor is then conveyed along a guide 8 to a transfer process where it faces the photoreceptor 5 . This paper 9 is first guided at one end by a separation guide tape 13 before the transfer process, and then guided to the transfer process opposite to the corona discharger 6. One end of the guided paper 9 is separated from the photoreceptor 5 by a separation guide tape 13, and the other part is in close contact with the photoreceptor 5, and the toner on the photoreceptor is transferred by the action of corona discharge. .

The toner image is transferred to the paper 9 as described above,
After the transfer, the paper 9 tries to be conveyed along the rotational direction of the photoreceptor 5, but one end of the paper 9 is guided away from the photoreceptor 5 by the separation guide tape 13, and the sheet 9 gradually moves away from the one end. It is separated into Then, the paper 9 guided by the separation guide tape 13
is guided to the vicinity of the pressure contact portion between the separation roller 10 and the separation guide 12, and its tip is held between the roller 10 and the guide 12. Separation roller 10
By sandwiching the paper 9 between the paper 9 and the separation guide 12, the paper 9 is moved in a direction necessary to resist the adhesion force between the photoreceptor 5 and the paper 9, that is, necessary for separation, and in a predetermined transport direction. Gain the strength to stay in place.

At the same time, as shown in FIG. 3, the back surface of the paper 9 is charged with a corona discharger 6 during the transfer process, and this charge induces an electric charge on the separating roller 10 side with the insulating layer 16 sandwiched therebetween. be done. After the paper 9 is separated by this induced charge, it is attracted toward the separation roller 10 by electrostatic force. Therefore, after the paper 9 is separated, the separation roller 10
Separation proceeds by rotation of the separation roller 10, 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 9 are in close contact with each other, since the insulating layer 16 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. In addition, the paper 9 is charged with a polarity opposite to that of the toner on the photoreceptor 5, so that the toner is attracted to the paper 9 side and transfer is performed.
This does not completely neutralize the charge on paper 9, but there is sufficient charge to induce charge on roller 10.

As described above, since the paper 9 is sucked toward the separation roller 10 after being separated, there is no lifting or oblique feeding of the paper, and the toner image is transferred in good condition without any transfer defects.

Further, as shown in FIG. 3, if an insulating layer 20 is also provided on the surface of the conductive guide plate 18, the separated sheets 9 can be more stably transported after being attracted by the guide plate 18. The separated paper 9 is guided along the guide plate 18 and led to fixing rollers 21 and 22, where the toner on the upper surface is fixed.

Here, the separation roller 10 is rotated at approximately the same speed as the conveyance speed of the paper 9, and the paper 9 is transferred to the roller 1.
There is no need to slide it on the surface of the paper. However, since the paper 9 needs to be conveyed while sliding on the guide plate 18, ribs 23 provided on the guide plate 18 in the conveyance direction of the paper 9
If the shape of the material is designed, it can be transported smoothly. Further, a structure may be adopted in which a smooth tape having a small coefficient of friction, such as a fluororesin, is attached or coated on the insulating layer 20 provided on the guide plate 18 to make the paper 9 easier to slide.

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 transfer material separation device of the present invention, in a device configured to sandwich a paper between a separation roller and a separation auxiliary means that presses against the roller, and to separate the transfer material by cooperation, the separation roller is made of a conductive material and grounded to the main body of the device, and the surface of this roller is covered with an insulating layer, and the charge of the charged transfer material induces charges of opposite polarity to the separation roller side. Since the transfer material after separation is sucked toward the roller side, the separation of the transfer material becomes more reliable, and even during transportation after separation, the transfer material is attracted to the roller, so stable transportation is possible without deviation from the predetermined transportation direction. can be expected.

[Brief explanation of the drawing]

Figure 1 is a side view showing an example of a conventional separation mechanism;
FIG. 2 is a perspective view showing an example of a separating device according to the present invention, and FIG. 3 is a sectional view showing the structure of a separating roller according to the present invention. 5: Photoreceptor, 6: Corona discharger, 9: Paper, 1
0: Separation roller, 11: Separation guide lever, 1
2: Separation guide, 13: Separation guide tape, 16:
insulation layer.

Claims (1)

[Claims] 1. In a separating device having a structure in which a charged paper is held between a separating roller and a separating auxiliary means to separate the paper from a member that is in close contact with the paper, the separating roller is formed of a conductive member and is grounded to the main body of the device. A paper separation device comprising a separation roller whose surface is covered with an insulating layer.