JPS60159866A - Preventing device of image blurring - Google Patents

Abstract

PURPOSE:To obtain a stable copy image of high quality by providing an isolating plate consisting of a fixing guide into two at least so that the potential generated in a pressuring roller of a fixer and heat of a fixing device have no influences upon a transfer paper after transfering. CONSTITUTION:A toner image on a photosensitive body is transferred to a transfer paper 2 indicated by a dash line, and the transfer paper 2 reaches a roller 1b following up the photosensitive body and is separated from the photosensitive body forcibly with a separating claw 5 by a mechanical method and is guided by fixing guide and reaches an isolating plate 8. At this time, a heating roller 6a and a pressuring roller 6b of a fixer 6 are pressed to each other and rotated, and >=-2kV potential is generated on the surface of a silicone rubber of the pressuring roller 1b by frictional charging; however, the transfer paper 2 is guide by the isolating plate 8 and is fixed and ejected because the isolating plate 8 is arranged near the part where the heating roller 6a and the pressuring roll 6b are pressed to each other, and thus, copy images without image blurring are always obtained stably. Since the fixing guide and the isolating plate are divided into two, heat of the fixing device is not directly conduct to the photosensitive body, and the photosensitive body is not damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a prevention device for preventing distortion of copied images in an electrophotographic copying apparatus.Constitution of a conventional example and its problemsGenerally, electrophotographic copying apparatuses A drum-shaped or belt-shaped photoreceptor is charged with a charger and exposed to light to completely form an electrostatic latent image. This is developed with toner, and with the transfer paper in contact with the developing surface, a transfer charger applies a corona discharge of opposite polarity to the charge held by the toner to the transfer paper, and the developed toner image on the photoreceptor is Transfer it to transfer paper. Next, a separating claw is used to separate the transferred transfer paper from the photoreceptor.

This transfer paper is guided to a fixing device by a fixing guide, and the toner image is fixed on the transfer paper. However, if the fixing continues as it is, the potential generated by frictional charging between the heating roller and the pressure roller of the fixing device will cause the transfer paper on which the toner image has been transferred to be disorganized just before it enters the fixing device, causing the quality of the toner image to deteriorate. There was a problem in that the resulting copied image had a low quality. This phenomenon in which the toner image is disturbed and proper copying cannot be performed is likely to occur in a thermocompression type fixing device. A thermocompression type fixing device generally rotates a heating roller whose surface is coated with Teflon and a pressure roller made of silicone rubber while pressing them together with a constant pressure.

The transferred toner image is passed through the transfer paper between the heating roller and the pressure roller, and the toner image is fixed onto the transfer paper by heat and pressure. However, as described above, in this fixing device, due to contact rotation between Teflon and silicone rubber, each is rubbed and frictional electrification occurs, and in particular, a surface potential of 12 KV or more is generated as a surface potential of the silicone rubber roller. This potential has an electrostatic effect on the toner on the transfer paper before it is fixed, causing a disturbance in the copied image that disturbs the toner image on the transfer paper. Conventionally, measures such as installing a silicone rubber roller static elimination brush have been taken to solve this problem, but they do not remove static electricity sufficiently and have problems with reliability such as a short lifespan due to friction of the static elimination brush. Ta.

FIG. 1 is a partially omitted diagram showing an example of a conventional copying machine.

In FIG. 1, 1 is an OPC belt-shaped photoreceptor, 1a
1b is a driving drum for the photoreceptor, and 1b is a driven roller for the photoreceptor, which causes the belt-shaped photoreceptor 1 to travel. A transfer paper 2 is guided by a transfer guide 3 onto the belt-shaped photoreceptor 1 on which a toner image has been developed by a developing device (not shown) and is brought into close contact with the belt-shaped photoreceptor 1. The toner image is transferred to the transfer paper 2 by the transfer charger 4, and the transfer paper 2 is transferred to the belt-shaped photoreceptor 1 by the separation claw 6.
The toner image is separated from the transfer paper 2 and guided by the fixing guide 7, and the toner image is fixed on the transfer paper 2 by the fixing device 6. In a copying machine having such a conventional configuration, a fixing guide 7 located between the fixing device 6 and the driven roller 1b of the photoconductor transfers the heat of the fixing device 6 to the belt-shaped photoconductor 1 via the fixing guide 7. This may cause the belt-shaped photoreceptor 1 to be deformed by the heat, or in extreme cases, the base film of the belt-shaped photoreceptor may be deformed, causing cracks to occur in the photosensitive layer on the surface, resulting in damage to the copied image. The disadvantage was that only low-quality copies could be made due to the influence of

OBJECTS OF THE INVENTION An object of the present invention is to provide a highly reliable image disturbance prevention device.

Structure of the Invention The image distortion prevention device of the present invention is located between the photoreceptor and the fixing device, and serves as a fixing guide for the transfer paper after transfer, and the potential generated in the pressure roller of the fixing device and the heat of the fixing device are A blocking plate consisting of at least two divided fixing guides is provided so as not to affect the transfer paper after transfer, and thereby a highly reliable and high quality copy image can be obtained.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows the configuration of a copying machine to which the image disturbance prevention device of the present invention is applied. In FIG. 2, 1 is a belt-shaped photoreceptor, 1a is a photoreceptor driving drum, 1b is a photoreceptor driven roller, 2 is a transfer paper, 3 is a transfer guide, 4 is a charging and transfer charger, 5 is a separating claw, and e is a heating roller 6a
7 is a fixing guide (hereinafter referred to as the fixing guide) located on the photoreceptor side, and 8 is a stainless steel material that functions as heat dissipation and static elimination for the pressure roller 6b. a shielding plate (hereinafter referred to as a shielding plate), which is also effective as a guide plate for guiding the transfer paper after transfer to the fixing device;
10 is a feeding roller, 11 is a pair of conveying rollers, 12 is a developing device, and 13 is a glass fiber lens 131L and a lamp 13 of the optical system.
an exposure device including b; 14 a photoreceptor cleaning device;
16 is a photoreceptor static elimination lamp, and 16 is a paper discharge tray.

With the above configuration, its operation will be explained below.

In FIG. 3, the toner image on the photoreceptor is transferred to the transfer paper 2 shown by the broken line, which reaches the photoreceptor driven roller 1b, is forcibly separated by a separating claw 6 by a mechanical method, and is transferred to the fixing guide. It is guided and reaches the blocking plate 8. At this time, the heating roller 6a and the pressure roller 6b of the fixing device 6 are in pressure contact with each other and rotate, and the pressure roller 6a is rotated by frictional electrification.
A potential of 12 KV or more is generated on the surface of the silicone rubber in b, but as shown in FIG. The transfer paper 2 is not affected by the potential of the transfer paper 6b.
is guided by the blocking plate 8, fixed, and ejected.
Copy images without image disturbance can always be stably obtained. Furthermore, by dividing the fixing guide and the shielding plate into two parts, the heat of the fixing amount does not directly reach the photoreceptor, thereby preventing damage to the photoreceptor. In the embodiments of the present invention, the shielding plate is made of stainless steel, but the material is not limited to stainless steel, and any material may be used as long as it has the function of eliminating static electricity, such as a copper plate. Further, if the fixing device has high heat resistance so that the heat of the fixing device does not affect the photoconductor, there is no need to separate the fixing guide and the blocking plate on the photoconductor side as in the present invention, and the blocking plate and the fixing guide can be separated. An integrated blocking plate may also be used.

Effects of the Invention As is clear from the above explanation, the present invention is located between a photoreceptor and a fixing device as a device for preventing disturbances in a copied image,
This serves as a fixing guide for the transfer paper after transfer, and applies pressure from at least a two-part fixing guide so that the potential generated in the pressure roller of the fixing device and the heat of the fixing device do not affect the transfer paper after transfer. By adding a blocking plate, stable and high-quality copied images can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted view showing a conventional copying machine, FIG. 2 is a side view of a copying machine to which an embodiment of the present invention is applied, and FIG. 3 is a partially enlarged side view of the same. 1...Photoreceptor, 2...Transfer paper, 6...
...Fuser, 6a...Heating roller, 6b
. . . Pressure roller, 7 . . . Fixing guide, 8 . . . Blocking plate. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure n @2 Figure 3 Figure 3

Claims (1)

[Claims] Located between the photoreceptor and the fixing device, it serves as a fixing guide for the transfer paper after transfer, and at least prevents the electric potential generated in the pressure roller of the fixing device and the heat of the fixing device from affecting the transfer paper after transfer. An image disturbance prevention device characterized by being provided with a blocking plate consisting of a two-divided fixing guide.