JPS60126678A - Transfer paper separating device - Google Patents

Abstract

PURPOSE:To improve a picture quality of a both face copying by making a separation auxiliary material approach a photosensitive roll before the tip of a transfer paper after a transfer reaches the photosensitive roll, and enlarging a distance between the photosensitive roll and the separation auxiliary material after the tip of the transfer paper contacted to the separation auxiliary material. CONSTITUTION:As soon as a transfer paper 2 is started to be transferred by a charger 10, a voltage of an electromagnetic switch 12 is cut off and a separation auxiliary material 11 is made to approach a photosensitive body driven roller 1b, and the transfer paper 2 advances and it is attracted to the separation auxiliary material 11. Subsequently, when electric conduction is executed to the electromagnetic switch 12 in a prescribed time after starting of the transfer, the transfer paper 2 recedes from the photosensitive body driven roller 1b in a state that it remains attracted to the separation auxiliary material 11, and it is separated from the photosensitive body 1. The transfer paper 2 advances further and reaches a fixing guide 13, and the separation is executed exactly. In this way, by making the separation auxiliary material recede from the photosensitive body except the time when it is required for separating the transfer paper, a toner adhesion from the photosensitive body is removed, and a picture quality in case of executing a both face copying is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for separating a photoreceptor and a transfer paper in an electrophotographic copying apparatus.

Structure of conventional examples and their problems Conventional transfer paper separation devices include those based on electrical processing using a separation charger, those based on mechanical processing using a separation belt, and those based on mechanical processing using the above-mentioned separation charger and separation claws. Some use a combination of physical and mechanical treatments.

Generally, an electrophotographic copying apparatus forms an electrostatic latent image by charging a photoreceptor formed in the shape of a drum or belt with a charging charger and exposing it to light. Develop this with toner,
With the transfer paper in contact with the developing surface, a transfer charger applies corona discharge to the transfer paper with a polarity opposite to the charge held by the toner, thereby transferring the developed toner image on the photoreceptor to the transfer paper. Next, when the transfer paper on which the toner image has been transferred is separated from the surface of the photoreceptor, because the transfer paper has an extra charge of the opposite polarity to the toner due to the corona discharge of the transfer stop, The transfer paper is attracted to the photoreceptor by this electrostatic attraction. This makes it difficult to separate the transfer paper from the photoreceptor. As one device for easily separating this, a separation charger is provided separately from the transfer charger, and this removes the excess charge applied during transfer.
A so-called electrostatic separation device is used in which the transfer paper is subjected to hypostatic treatment so that the transfer paper naturally separates from the photoreceptor due to its rigidity and weight.

As described above, the electrostatic separation device must include a separation charger in addition to the transfer charger. Furthermore, since the separation charger uses alternating current (AC) corona discharge, it is necessary to provide an AC high voltage power source.

On the other hand, a separation belt device that processes the separation method mechanically has a transfer guide 6 as shown in FIGS. 1 and 2.
The transfer paper 2 guided by the photoreceptor drum 1 is
The toner image formed on the surface of the photosensitive drum 1 by the image forming means is transferred by the transfer charger 6.

At this time, one end A of the transfer paper 2 is held between the separation belt 3 and the separation roller 4, and the end of the transfer paper 2 away from the image area is moved along the end of the transfer material conveyance path of the photoreceptor drum 1. It advances without contacting the photoreceptor drum 1.

On the other hand, the portion of the image area near the center other than the above-mentioned end portion is in contact with the photoreceptor drum 1-, and the toner image is transferred by the transfer charger 5 and advances at the same speed as the photoreceptor drum 1, and is transferred and separated. will be carried out. As is clear from the above, the end portion of the transfer paper held by the separation belt exists separately from the image area. Therefore the edges of the copied image (minutes).

The image (the part held by the release belt) has been deleted, and there is a drawback that it is not possible to make a full copy.

There is also another separation device that uses a separation charger and separation claws together. As shown in FIG. 3, this device uses a transfer guide 6 to transfer a toner image formed on the surface of the photoreceptor drum 1 by an image forming means to the transfer paper 2 guided to the photoreceptor drum 1 by a transfer charger 6. The image is transferred and then separated by a separation charger 7. However, since the force that separates the transfer paper 2 from the photoreceptor drum 1 is likely to change depending on ambient environmental conditions such as humidity, there are times when the transfer paper 2 is not separated sufficiently from the photoreceptor drum 1 or is not separated at all. be.

At these times, the transfer paper 2 is separated from the photoreceptor drum 1 by the separating claw 8 in the direction of the arrow as shown by the dashed line. However, in this case, there is a drawback that the unfixed toner image held on the surface of the transfer paper 2 is rubbed when it comes into contact with the separation claw 8, and a mark is formed on the toner image. Furthermore, since the separating claw constantly contacts and rubs the photoreceptor, there are problems such as scratches on the surface of the photoreceptor.

A transfer paper separation apparatus shown in FIG. 4 is a separation apparatus that separates the transfer paper from the photoreceptor without using a separation charger, separation belt, or separation claw as a device that solves the above-mentioned problems. As shown in FIG. 4, the transfer paper 2 guided by the transfer guide 6 to the belt-like photoreceptor 1 in contact with the photoreceptor driving drum 1a transfers the toner image formed on the surface of the belt-like photoreceptor 1 by the image forming means. The image is transferred by a transfer charger 6. The leading edge of the transferred transfer paper advances to the photoconductor driven roller 1b. At this time, the leading edge of the transfer paper 2 tries to move straight due to the rigidity of the paper, but the belt-shaped photoreceptor 1 that is in contact with the leading edge of the transfer paper 2 changes due to the curvature of the photoreceptor driven roller 1b, and as a result, the transfer paper 2 The tip of the photoreceptor 1 and the belt-shaped photoreceptor 1 in contact with it separate from each other in a very short time. As the transfer paper 2 further advances, the electrostatic adsorption force on the photoconductor 1 due to the electric charges charged on the transfer paper 2 during transfer becomes relatively stronger, partly because the force due to the rigidity of the transfer paper 2 weakens. , the transfer paper 2 is again attracted to the belt-shaped photoreceptor 1. A device that skillfully utilizes the phenomenon described above is an electrostatic adsorption separation device. A separation aid 9 is placed at a position where the transfer paper 2 is separated from the body 1, and the leading edge of the transfer paper 2 is brought into contact with the separation aid 9.
There is a device in which the transfer paper 2 after transfer is attracted to the separation auxiliary material 9 and separated by the electrostatic adsorption force of the band'. However, with this device, dirt adheres to the separation auxiliary material 9 on the surface of the separation auxiliary material 9 due to toner scattering within the copying machine. Due to this toner stain, the back side of the transfer paper becomes stained with toner when the transfer paper is separated, making it impossible to perform double-sided copying using the front and back sides of the transfer paper. Furthermore, in order to solve this problem, it is necessary to rotate the separation auxiliary material and apply a cleaning method such as bringing a cleaning brush into contact with the separation auxiliary material, resulting in a complicated configuration as a copying machine. There is.

Purpose of the invention.

An object of the present invention is to provide a transfer paper separation device that separates transfer paper from a photoconductor without using a separation charger, a separation belt, or a separation claw, and which realizes full-scale copying of images and high-quality double-sided copying. It is.

Composition of the Invention The transfer paper separation device of the present invention disposes a separation aid at a position where the transfer paper separates from the photoreceptor due to the charging of the transfer paper itself after transfer and the rigidity of the transfer paper at the photoreceptor roll portion, and separates the transfer paper after transfer. The separation aid is brought close to the photoreceptor roll before the leading edge of the transfer paper reaches the photoreceptor roll, and after the leading edge of the transferred paper comes into contact with the separation aid, the separation aid is separated from the photoreceptor roll. The transfer paper is separated from the photoreceptor by increasing the distance between the transfer paper and the photoreceptor. In addition, the tip of the separation auxiliary material is configured to have an inclined surface parallel to the tangent to the photoreceptor roll, which allows stable separation of the transfer paper and enables full-scale copying of the image. The back side of the printer is free from toner stains, and high-quality double-sided copying is possible.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 5 shows a schematic diagram of an example of a copying machine to which the transfer paper separating device of the present invention is applied. In Figure 5, 1 is 0P
Belt-shaped photoreceptor (hereinafter referred to as
(referred to as a photoreceptor) is running at a speed of 1sovan/lJy. 1a is a 120 mm diameter photoreceptor sales drum, 1b
1 is a photoconductor driven roller with a diameter of 30 mm, 2 is a transfer paper, 6 is a transfer guide, 10 is a charging and transfer charger, 11 is a separation aid made of aluminum material, 12 is an electromagnetic switch that drives the separation aid, 12a is a A spring built into the electromagnetic switch, 13 a fixing guide, 14 a cassette containing the transfer paper 2, 16 a feed roller, 16
17 is a pair of conveying rollers, 17 is a fixing device, 18 is a developing device, 19
The optical system includes an optical fiber lens 19a and a lamp 19b.
2o is a photoreceptor cleaning device; 2o is a photoreceptor cleaning device;
1 is a photoreceptor static elimination lamp, and 22 is a paper discharge tray.

The operation of the transfer paper separation device of this embodiment configured as described above will be described below.

The transfer paper 2 indicated by a broken line in FIG. 6 is sent to the transfer guide 6 by a pair of transport rollers 16.

Next, the transfer paper 2 is guided to the photoreceptor 1 and is brought into close contact with the photoreceptor 1 electrostatically, and the toner image formed on the photoreceptor 1 is transferred by a charging and transfer charger 10 (hereinafter referred to as a charger). At this time, at the same time as the charger starts discharging (DC high voltage is applied to the charger 10), the electromagnetic switch 1
2 is cut off, and the electromagnetic switch 12
The spring 12a inside the spring 12a moves the separation auxiliary material 11 from the center perpendicular of the photoconductor driven roller 1b to the traveling direction of the transfer paper 2 at an angle of 320 degrees parallel to the tangent to the photoconductor 1 at a distance of 0.7 degrees. Bring it closer. The leading edge of the transfer paper 2 indicated by a broken line in FIG. 7 moves straight due to the rigidity of the paper, and the transfer paper 2 is automatically separated from the photoreceptor for an instant at the curved portion of the photoreceptor driven roller 1b. Since the separation auxiliary material is placed at this location, the leading edge of the transfer paper 2 comes into contact with the separation auxiliary material 11, and is electrostatically attracted to the separation auxiliary material 11 by the electric charge charged to the transfer paper 2 by the transfer.

On the other hand, the photoreceptor 1 is running at a speed of 1 soam/sec, and the distance between the charger 10 and the center of the photoreceptor driven roller 1b is set to 160 degrees.

Further, the distance from the center of the photoreceptor driven roller 1b to the end of the fixing guide 13 is set to 15u+.

Therefore, the distance from the charger 10 to the fixing guide 13 is 1661II, and the time it takes for the transfer paper 2 to travel this distance is 1.1 seconds.

At the same time as the transfer paper 2 begins to be transferred by the charger 10, the voltage of the electromagnetic switch is cut off, and the separation aid 11 is brought close to the photoreceptor driven roller 1bVc, and the transfer paper 2 advances and adsorbs to the separation aid 11. Next, when the electromagnetic switch is energized 1.1 seconds after the start of transfer, the transfer paper 2 moves away from the photoconductor driven roller 1b while being attracted to the separation aid 11, and is separated from the photoconductor. The transfer paper 2 further advances and reaches the fixing guide 13 as shown by the dashed line A in FIG. 7, thereby ensuring separation. Although aluminum was used as the material for the separation aid in the above embodiments, it is not limited to aluminum; any material may be used as long as it has the function of electrostatically adsorbing the transfer paper due to the electric charge. For example, stainless steel, brass, etc. can be used. Although the shape of the tip of the separation auxiliary material is an inclined surface parallel to the tangent line of the photoreceptor roll portion, it is most suitable because it has many advantages in processing and assembling the product.

In particular, it is easy to adjust the gap between the separation auxiliary material and the photoreceptor, and there is an advantage that the adjustment can be done smoothly with respect to the advance of the transfer paper.

Effects of the Invention As is clear from the invention described above, the present invention is a device for separating transfer paper from a photoconductor, and uses the charging of the transfer paper itself after transfer and the rigidity of the transfer paper in the photoconductor whirl portion to separate the transfer paper from the photoconductor. A separation aid is placed at the separation position, and the separation aid is brought close to the photoconductor roll before the leading edge of the transfer paper after transfer reaches the photoconductor roll, so that the leading edge of the transfer paper after transfer reaches the separation aid The transfer paper is separated from the photoreceptor by increasing the distance between the photoreceptor roll and the separation aid after contact with the photoreceptor, eliminating the need for a conventional separation charger and AC power source. , also separate bell]
・Since no separation claws are required, it is possible to copy the entire image, and the problem of separation claw marks is eliminated. Furthermore, since the separation auxiliary phase is brought close to the photoreceptor only when necessary for separation and kept away from the photoreceptor at other times, toner adhesion from the photoreceptor can be removed. This toner adhesion occurs when a paper jam occurs before or during the copying machine forms a toner image on the photoconductor and transfers it to the transfer paper.Generally, the copying machine is turned off and the jammed paper is removed. Finally, turn on the power, let it warm up, and make it ready to start copying. During this warming up, the toner image on the photoreceptor during paper jam is cleaned.
At this time, when the toner image approaches the separation auxiliary material, if the gap between the photoreceptor and the separation auxiliary material remains close as in the conventional method, toner agglomeration will certainly occur on the separation auxiliary material.

In the present invention, since the separation auxiliary material is brought close to the photoreceptor only when the transfer paper is separated, the problem of toner staining on the separation auxiliary material is solved. Therefore, since toner stains on the back side of the transfer paper after separation do not occur, high-quality double-sided copying using the front and back sides of the transfer paper can be obtained. Furthermore, in the present invention, by making the tip of the separation auxiliary material have an inclined surface parallel to the tangent to the photoreceptor roll, the gap with the photoreceptor can be easily adjusted, and the transfer paper can advance smoothly. This enables more stable transfer paper separation.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the conventional device, Figure 2 is its side view, and Figure 3 is a perspective view of the conventional device.
4 and 4 are side views of other conventional devices, FIG. 6 is a schematic diagram of an example of a copying machine to which an embodiment of the present invention is applied, and FIGS. 6 and 7 are side views of an embodiment of the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1-... Belt-shaped photoreceptor, 1b... Photoreceptor driven roller, 11... Separation auxiliary material, 12 Electromagnetic switch, 12a... Spring. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 5 Figure 6. Figure 7

Claims (2)

[Claims] (1) A separation aid is placed at a position where the transfer paper separates from the photoreceptor due to the charging of the transfer paper itself after transfer and the rigidity of the transfer paper at the photoreceptor roll part, and the leading edge of the transfer paper after transfer is placed at the photoreceptor roll part. The separation auxiliary material is brought close to the photoreceptor roll before reaching the separation auxiliary material, and after the leading edge of the transfer paper after transfer comes into contact with the separation auxiliary material, the distance between the photoreceptor roll and the separation auxiliary material is increased and the transfer paper is removed. 1. A transfer paper separating device characterized in that the transfer paper separating device is configured to separate the paper from the photoreceptor. (2) The transfer paper separation device according to claim (1), wherein the tip of the separation auxiliary material has an inclined surface parallel to a tangent to the photoreceptor roll portion.