JPS60159862A - Preventing device of image blurring - Google Patents

Abstract

PURPOSE:To obtain copies of high quality without image blurring by constituting a device so that a transfer paper after transfer goes down perpendicularly and goes straightly in the intermediate are between the point, where the transfer paper is separated from a photosensitive body, and fixation start point without contacting members except air by rigidity of the transfer paper and is fixed thereafter. CONSTITUTION:A transfer paper 2 indicated by a dash line is sent to a transfer guide 3 by a pair of carrying rollers 9. The transfer paper 2 is led to a photosensitive body 1 and is brought into closely contact with it electrostatically, and a toner image formed on the surface of the photosensitive body 1 is transferred by a charger 4. The transfer paper 2 and the photosensitive body 1 advance in the same speed, and the front end of the transfer paper 2 reaches a roller 1b following up the photosensitive body; and if the radius of curvature of the photosensitive body 1 is set to <=10R, the transfer paper 2 cannot follow up variation of the photosensitive body 1 in a part of this curvature and has the front end separated from the photosensitive body 1 and goes straightly by its rigidity. Since the transfer paper 2 goes down perpendicularly, it is carried directly to a fixing device 6 and is fixed through fixing guides are not provided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a prevention device for preventing distortion of a copied image in an electronic reproduction apparatus.

Conventional Structures and Problems Generally, in an electronic copying apparatus, a drum-shaped or belt-shaped photoreceptor is charged with a charger and exposed to light to form an electrostatic latent image. This is developed with toner, transferred to a transfer charger while the transfer paper is in contact with the developing surface of the photoconductor, and a corona discharge of opposite polarity to the charge held by the toner is applied to the transfer paper, and the developed toner is transferred to the transfer paper. Transfer the image to transfer paper. Next, in order to separate the transferred transfer paper from the photoconductor, a separation charger is used to apply an AC corona discharge to remove the electric charge of the transfer paper and toner itself, which has been charged due to transfer. This increases the rigidity and weight of the transfer paper. naturally separates 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.

The configuration described above is a common electrophotographic copying device, but there is an increasing trend to simplify the configuration of copiers and commercialize smaller, cheaper products. A copying machine has been invented in which charging and transfer are performed using a single charger, the separate charger is removed, and the AC high voltage power source is also removed. FIG. 1 shows one conventional example of these. Transfer guide 3 as shown in Figure 1! The transfer paper 2 guided by the belt-shaped photoconductor 1 attached to the photoconductor material drum 1a and the photoconductor driven roller 1b is transferred to the belt-shaped photoconductor 1 by the image forming means.
The toner image formed on the surface of the toner image is transferred by a charging and transfer charger 4. Next, the transfer paper 2 and the belt-shaped photoreceptor 1 advance at the same speed, and when the leading edge of the transfer paper 2 reaches the photoreceptor driven roller 1b, the transfer path 2 Due to this curvature, the transfer paper 2 moves straight due to its rigidity, and the transfer paper 2 separates from the belt-shaped photoreceptor at this curvature. When the transfer paper 2 and the belt-shaped photoreceptor 1 further advance, the leading edge of the transfer paper 2 advances downward due to its own weight, and the fixing guide 6
The toner image contacts the transfer paper 2, advances further, is guided to the fixing device 6, and the toner image is fixed on the transfer paper 2. However,
When a so-called double-sided copy is performed in which the transfer paper that has been copied once is turned over and copied again, the toner image on the belt-shaped photoreceptor 1 is transferred to the transfer paper 2 at the moment the transferred transfer paper 2 contacts the fixing guide in FIG. 1. There is a problem in that so-called image disturbance occurs in which unfixed toner images are scattered. Therefore, at present, double-sided copying is not possible. This development does not occur in the conventional copying machine configuration in which a separate charger eliminates the charge on the transfer paper and toner after transfer.

In addition, the copying machine configurations in which these image disturbances occur are common in that they separate the transfer paper from the photoreceptor without using a separation charger, such as separation belts, separation claws, and the devices described above in the conventional example. There is a method of increasing the curvature of a part of the photoreceptor and naturally separating the transfer paper at that part. The common point between these two methods is that the transfer paper itself is charged with electricity due to transfer because the transfer paper is separated from the photoreceptor without static electricity removal. When the paper comes into contact with the fixing guide, the unfixed toner image on the transfer paper scatters, resulting in image disturbance, which has the disadvantage that high-quality screen copying cannot be achieved.

The reason why image disturbance occurs when double-sided copying is performed is because the heat from the first fixing removes moisture from the transfer paper after transfer, and the resistance value of the transfer paper itself is high, resulting in an increase in the amount of charge.

Therefore, if this transfer paper is used as double-sided copying paper, the amount of charge accumulated on the transfer paper due to the second transfer will be significantly increased compared to the first transfer, so this transfer paper will be removed from the photoreceptor. When the transfer paper is separated and comes into contact with the fixing guide, the charge on the transfer paper is rapidly removed, and at that moment unfixed toner on the transfer paper scatters, causing image disturbance. Therefore, image disturbance does not occur in the first copy, but image disturbance occurs in the second copy (double-sided copying) due to the amount of charge that the transfer paper has after being separated from the photoconductor, in other words, the transfer paper is attached to the fixing guide. This is because the amount of change in charge that is removed when the two contacts contact each other is large. In addition, although image disturbance occurs under normal conditions during double-sided copying, when a polyester sheet with a high resistance value is used as the transfer paper, image disturbance occurs during the first copying. Therefore, conventional copying machines have the disadvantage that the types of transfer paper that can be used are severely limited.

OBJECTS OF THE INVENTION An object of the present invention is to provide an image disturbance prevention device for preventing disturbance of unfixed toner images in a copying machine configured to separate a transfer paper from a photoreceptor without using a separation charger.

Structure of the Invention The image disturbance prevention device of the present invention makes the traveling direction of the transfer paper after transfer vertically downward, and prevents the transfer from occurring in an intermediate area between the point where the transfer paper separates from the photoreceptor and the fixing start point by the fixing device. Due to the rigidity of the paper, it travels in a straight line without contacting anything other than the atmosphere, and then is fixed by the above fixing device, which eliminates image distortion and enables high-quality double-sided copying, with no restrictions on the material of the transfer paper. There is no such thing.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

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 an OPC belt-shaped photoreceptor (hereinafter referred to as 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. . - (hereinafter referred to as a charger), 6 is a fixing device, 7 is a transfer paper 2
8 is a feed roller, 9 is a pair of transport rollers 1o is a developing device, 11 is an exposure device including an optical system including a glass fiber lens 11a and a lamp 11b,
12 is a cleaning device, 13 is a photoreceptor static elimination lamp, 1
4 is a paper discharge tray.

It has the above configuration, and its operation will be explained below.

The transfer paper 2 indicated by a broken line in FIG. 3 is sent to the transfer guide 3 by a pair of transport rollers 9.

Next, the transfer paper 2 is guided to the photoreceptor 1, and the toner image formed on the surface of the photoreceptor 1 is electrostatically attached to the charger 4.
Transcribed by. When the transfer paper 2 and the photoreceptor 1 advance at the same speed, the leading edge of the transfer paper 2 reaches the photoreceptor driven roller 1b, and the curvature of the photoreceptor 1 is below the radius of 1oR.
At this curvature, the transfer paper 2 is unable to follow the change in the photoreceptor 1, and the leading edge of the transfer paper 2 separates from the photoreceptor 1, and moves straight due to the rigidity of the transfer paper 2. Furthermore, since the transfer paper 2 is oriented vertically downward, it is directly conveyed to the fixing device 6 and fixed thereon without the need for a conventional fixing guide. In this way, even if the photoreceptor driven roller 1b and the fixing device 6 are provided at a sufficient distance, the traveling direction of the transfer paper 2 is vertically downward, so that the transfer paper 2 can be prevented from coming into contact with any member other than the atmosphere. Since it is possible to stably reach the fixing start point of the fixing device 6 and fix the image, it is possible to make high-quality copies without image distortion without limiting the material of the transfer paper.

In the embodiments of the present invention, the description is limited to a copying machine that uses an OPC belt-shaped photoreceptor, but the same effect is achieved not only in an OPC belt-shaped copying machine but also in a copying machine that uses a selenium photoreceptor drum. It is something. '=Also, as a method for splitting the transfer paper after transfer, the curvature of the photoconductor driven roller is increased, and this method is limited to copying machines that use a natural separation method that utilizes the straightness due to this curvature and the rigidity of the transfer paper. Although the method described above is not limited to this method, for example, in a method using a separating claw or in a copying machine using a separating belt, the image can be fixed by directly fixing the image with a fixing device without letting the separated transfer paper come into contact with any member other than the atmosphere. It is possible to obtain the effect that no disturbance occurs.

Effects of the Invention As is clear from the above description, the present invention provides a device for preventing disturbances in a copied image, in which the traveling direction of the transfer paper after transfer is vertically downward, and the point at which the transfer paper separates from the photoreceptor is After the transfer paper moves straight without contacting any member other than the atmosphere due to the rigidity of the transfer paper in the intermediate region between the fixing start point and the fixing start point by the fixing device,
By configuring the image to be fixed by the fixing device described above, high-quality copies without image distortion can be obtained without limiting the material of the transfer paper.

[Brief explanation of the drawing]

FIG. 1 is a side view of a conventional example, FIG. 2 is a side view of an embodiment of a copying machine to which the present invention is applied, and FIG. 3 is a partially enlarged view of FIG. 2. 1...Photoreceptor, 2...Transfer paper, 6...
...Fixing device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 1 (1゜Figure 2

Claims (1)

[Claims] The direction of movement of the transfer paper after transfer is vertically downward, and the rigidity of the transfer paper causes it to come into contact with a member other than the atmosphere in an intermediate region between the point where the transfer paper separates from the photoreceptor and the start point of fixing by the fixing device. An image disturbance prevention device configured to move straight without any problem and then be fixed by the fixing device.