JPH0428643A - Sheet carrying guide for electrophotographic device - Google Patents

Abstract

PURPOSE:To intend a lighter weight, prevent bad transfer and stably carry paper to a fixing device by forming at least part of the paper guide face of a guide mainframe of semiconductive material. CONSTITUTION:A guide mainframe 21 which has a paper guide face 22 thereon is set up between a transfer device 10 and a fixing device 30. At least part of the paper guide face 22 of the guide mainframe 21 is formed of semiconductive material. In this way, no excessive accumulation of charges occurs under a low humidity circumstance to prevent the floatation of sheets. Also, bad transfer which results in a great amount of discharged electrons given out of the back of paper on the paper carrying guide face 22 is prevented under a high humidity circumstance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper conveyance guide for an electrophotographic apparatus. More specifically, the present invention relates to a paper conveyance guide for guiding a paper onto which a toner image has been transferred by a transfer device to a fixing device.

[Conventional technology 1 FIG. 6 shows the general configuration of a conventional electrophotographic apparatus.

In the figure, 1 is the main body of the apparatus, and inside the main body 1 there are photosensitive drums 2. Charging device 3. Optical system 4. Developing device5. Transfer device 10. A paper conveyance guide 20, a fixing device 30, and the like are provided.

When printing using this electrophotographic apparatus, the peripheral surface of the photosensitive drum 2 is charged by the charging device 3 (for example, -650V), and the charged photosensitive drum 2
A laser beam 4a is irradiated from the optical system 4 onto the circumferential surface of the print head 4 based on the print data. Toner 9 in the developing device 5 is electrostatically adhered to the laser beam irradiated area. Here, a bias voltage (for example, -650V) is applied to the developing device 5, and the toner 9 is charged (-650V).

Then, as shown in FIG. 4, in the transfer device 10, the back side of the paper P fed via the paper feed roller 7 etc. is charged with an electric charge of opposite polarity to the polarity of the toner 9.
The toner image attached to the laser beam irradiated area is transferred from the photosensitive drum 2 to the surface of the paper P. The paper P onto which the toner image has been transferred is guided by the paper conveyance guide 20 and sent to the fixing device W30. The toner image is then fixed onto the paper P by the fixing device M, 30.

Here, as shown in FIGS. 4 and 5, the paper conveyance guide 20 includes a guide body 21 and the like, which is located between the transfer device 10 and the fixing device rIt30 and has a paper guide surface 22 formed thereon. This guide body 21 is made of an insulating material such as plastic. Further, the paper guide surface 22 of the guide body 21 has a flat part 23 and a flat part 23 so that the paper P can be conveyed smoothly with a small contact area.
3 and a plurality of ribs 24 formed to protrude from the ribs 3.

Incidentally, during the printing operation, charges having the same polarity as the discharge charges supplied to the back surface of the paper P in the transfer device 10 are accumulated in the guide main body 21 due to friction with the paper P or the like. Therefore, an electrostatic repulsive force acts on the paper P and the guide body 21, and the paper P may be lifted off the paper guide surface 22 of the guide body 21, resulting in a paper jam or the like. Such a phenomenon is particularly likely to occur in a low humidity environment.

As a measure to prevent such sheet lifting, it is possible to form the guide body 21 from a conductive material such as metal. When the guide body 21 is formed in this way,
Since a kind of mirror image force (gravitational force) acts between the electric charge on the band on the paper PJj surface and the paper guide surface 22 of the guide body 21, the paper P is stably transported to the fixing device 30 while preventing it from floating up. You will be able to do it. However, if the paper P absorbs moisture in a high-temperature environment, the discharge charge supplied to the back surface of the paper P by the transfer device 10 may leak through the guide body 21 in large quantities, so that the amount of charge necessary and sufficient for transfer is insufficient. It may not be possible to apply this to the back side of the paper P, which may result in transfer failure.

Therefore, conventionally, in order to prevent the occurrence of paper lifting and transfer defects and to stably convey the paper P from the transfer device 10 to the fixing device 30, a part of the paper guide surface 22 of the guide body 21 has been removed. Leave a ground plate made of conductive material 2
5 to form the paper conveyance guide 20. Specifically, the earth plate 25 is formed with a trough 26 through which the rib 24 of the guide body 21 passes. This earth plate 25
is mounted so that the rib 24 of the guide main body 21 is exposed from the eraser 26. Note that the ground plate 25 is used during printing.
It is formed so as not to come into contact with the paper P.

[Problem U to be Solved by the Invention] By the way, the paper conveyance guide 20 having the above configuration has the following problems.

■In order to eliminate paper lifting and transfer defects, it is necessary to delicately adjust the positional relationship and covering area of the ground plate 25 with respect to the guide body 21, but it is extremely difficult to perform such adjustment work perfectly. be. Therefore, the paper transport guide 20 has the properties of a paper transport guide made of a conductive material, and sometimes has the properties of a paper transport guide made of an insulating material, thereby eliminating paper lifting, transfer defects, etc. Can not do it.

■ Also, the rib 24 of the paper conveyance guide 20 is connected to the ground plate 2.
5, the rib 24 is charged with charges of the same polarity as the discharge charges supplied to the surface of the paper P'M in the transfer bag 'f110 due to friction with the paper P. Therefore, the charged rib 24 causes the paper P to
Discharge or the like may be caused on the back surface of the paper P, and the toner image transferred onto the paper P may be disturbed. The phenomenon of peeling is particularly likely to occur in low humidity environments.

(2) Moreover, since most of the paper guide surface 23 of the guide body 21 is covered with the ground plate 25, the paper conveyance guide 20 becomes large and cannot meet the current demands for miniaturization of electrophotographic devices. It has its drawbacks.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a paper conveyance guide for an electrophotographic apparatus that is downsized and capable of stably conveying paper while preventing transfer defects and the like.

[Means for Solving the Problems] The invention as set forth in claim 1 provides a paper transport device for an electrophotographic apparatus having a guide body disposed between a transfer device and a fixing device and on which a paper guide surface is formed. The invention as set forth in claim 2 is characterized in that at least a part of the paper guide surface of the guide body is formed of a semiconductive material. is 108Ω・■〜1014Ω・
The invention according to claim 3 is characterized in that the guide body is made of a semiconductive material having a surface resistivity of 10 8 Ω to 1.
It is characterized by being formed from a semiconductive material with a resistance of 0.014Ω.

[Function] In the invention described in claim 1, at least a part of the paper guide surface of the guide body is formed of a semiconductive material. Therefore, even in a low-humidity environment, there is no accumulation of excessive charge, and paper lifting etc. are prevented.

In addition, even in a high temperature environment, the paper conveyance guide does not release a large amount of charge from the back surface of the paper, thereby preventing transfer defects from occurring.

Furthermore, since the paper conveyance guide can be formed without using a ground plate, miniaturization can be easily achieved.

Therefore, it is possible to reduce the size and to stably transport the paper to the fixing device while preventing transfer defects and the like.

In the invention set forth in claim 2, in particular, at least a part of the paper guide surface of the guide body has a volume resistivity value of 108Ω.
- Since it is formed from a semiconductive material of C11 to 1014 Ω·cm, it is possible to reduce the size, and to effectively prevent transfer defects and the like, and to stably transport the paper.

Similarly, in the invention described in claim 3, at least a part of the paper guide surface of the guide body has a surface resistivity of 108Ω.
Since it is made of a semiconductive material with a resistance of ~10I4Ω, it is possible to achieve miniaturization, and to effectively prevent transfer defects and the like, and to stably transport the paper.

[Example] An embodiment of the present invention will be described based on the drawings.

As shown in FIGS. 1 and 2, the paper conveyance guide of the electrophotographic apparatus according to this embodiment is provided between the transfer device 10 and the fixing device 30, and has a paper guide surface 22, etc. formed thereon. It is composed of a guide body 21 and the like.

Components that are the same as those shown in FIGS. 4 and 5 are designated by the same reference numerals, and their explanations will be omitted or simplified.

Here, at least the paper guide surface 22 of the guide body 21
A part of the paper is made of a semiconductive material to prevent paper lifting and transfer defects.

In this embodiment, the entire guide body 21 is made of a semiconductive material in order to more effectively prevent sheet lifting, transfer defects, and the like. As the semiconductive material, ABS I)j resin containing conductive carbon is selected.

FIG. 3(a) shows the results of an experiment in which the volume resistivity of the paper conveyance guide was variously changed by changing the carbon content of the guide body 21. In the figure, 23℃ and 35℃ indicate room temperature, and 20%RH, 8℃
0% RH indicates the amount of relative humidity, O indicates that the transfer result is good, and X indicates that poor transfer occurred.

As shown in the figure, the guide body 21 has a volume resistivity of 1.
Good results were obtained in low-humidity environments (23°C, 20% RH) and high-humidity environments (35°C, 80% RH) when formed with semiconductive materials of 06Ω·■ to 1014Ω·cm. When setting the volume resistivity value to 106Ω・α, some transfer force scratches may occur in a high humidity environment, so in order to optimize Conductive materials are preferred.

Note that when the volume resistivity value was increased to 1016 Ω·■, disturbances (for example, vertical image streaks) occurred in the transferred image in a low humidity environment. For reference, we also experimented with a paper conveyance guide made of conductive material, but it resulted in poor transfer in a high-humidity environment.

According to this embodiment, the guide main body 21 of the paper conveyance guide is formed of a semiconductive material, so that there is no accumulation of excessive charge and it is possible to prevent the paper from floating or the like. Further, since the guide main body 21 does not allow discharged charges to escape from the back surface of the paper P, transfer defects and the like are prevented from occurring.

Furthermore, since the paper conveyance guide can be formed without using a ground plate, it is possible to easily achieve miniaturization. Therefore, it is possible to reduce the size and to stably transport the paper while preventing transfer defects and the like.

In the above embodiment, the guide body 21 of the paper conveyance guide is made of A B containing conductive carbon.
It was formed from S 1fil fat, but A B S t! )I
It may be formed by subjecting at least a portion of the paper guide surface 22 (for example, the ribs 24) of the guide body 21 made of oil to a surface treatment such as applying a conductive paint.

FIG. 3(b) shows the results of an experiment in which the surface resistivity of the paper guide surface 22 of the paper conveyance guide was varied in various ways by changing the conductive properties of the conductive paint.

As shown in the figure, when the surface resistivity of the paper guide 22 of the paper conveyance guide is set to 106Ω to 1Q14Ω, under a low humidity environment (23°C 20%RH) and a high temperature environment (35°C
Good results were obtained with C80%RH), but if the surface resistivity is 106Ω, some transfer force scratches may occur in a highly humid environment, so to optimize the surface resistivity, set the surface resistivity to 108Ω or more. It is desirable that the surface resistivity be 1014 Ω.6 Note that when the surface resistivity was increased to 10'6 Ω, disturbances (for example, vertical image streaks) occurred in the transferred image in a low humidity environment.

[Effects of the Invention] According to the invention described in claim 1, at least a part of the paper guide surface of the guide body is formed of a semiconductive material, so that it is possible to reduce the size and prevent transfer defects. Paper can be stably transported to the fixing device.

According to the invention set forth in claim 2, at least a part of the paper guide surface of the guide body has a volume resistivity value of 10
Since it is made of a semi-conductive material with a resistance of 8Ω・■~io'-'Ω・cm, it is possible to achieve miniaturization, and to effectively prevent transfer defects and the like, and to stably transport the paper to the fixing device. can.

According to the third aspect of the invention, at least a part of the paper guide surface of the guide body has a surface resistivity of 108Ω.
Since it is made of a semiconductive material with a resistance of ~1014 ohms, it is possible to reduce the size and to effectively prevent transfer defects and the like, and to stably feed the paper to the fixing device.

[Brief explanation of the drawing]

1 to 3 are diagrams showing one embodiment of the present invention, in which FIG. 1 is an external perspective view, FIG. 2 is a diagram for explaining the positional relationship with a transfer device and a fixing device, and FIG. 3 is a diagram showing an embodiment of the present invention. FIG. 3 is a diagram for explaining the experimental results of wiping to optimize the paper conveyance guide resistance value. FIGS. 4 and 5 are diagrams showing a conventional transfer device.
The figure is a diagram for explaining the positional relationship between the transfer device and the fixing device, and FIG. 5 is an exploded perspective view for explaining the structure. FIG. 6 is a sectional view showing a schematic configuration of an electrophotographic apparatus to which a conventional transfer device is applied. DESCRIPTION OF SYMBOLS 10... Transfer device, 21... Guide main body, 22... Paper guide surface of guide main body, 30... Fixing device. Fig. 3 Paper conveyance guide resistance value optimization test (b) Fig.

Claims (3)

[Claims] (1) In a paper conveyance guide for an electrophotographic device having a guide body located between a transfer device and a fixing device and on which a paper guide surface is formed, at least a part of the paper guide surface of the guide body is formed of a semiconductive material. A paper conveyance guide for an electrophotographic device, characterized in that: (2) At least a part of the paper guide surface of the guide body has a volume resistivity of 10^8 Ω·cm to 10^1^4
2. The paper conveyance guide for an electrophotographic apparatus according to claim 1, wherein the paper conveyance guide is made of a semiconductive material having a resistance of Ω·cm. (3) At least a part of the paper guide surface of the guide body is formed from a semiconductive material having a surface resistivity of 10^8Ω to 10^1^4Ω.
Paper transport guide for the electrophotographic device described in Section 1.