JPS60121475A - Transfer paper separating device - Google Patents

Abstract

PURPOSE:To separate a transfer paper from a photosensitive body without a separating charger, a separating pawl, or the like by arranging a separation aiding belt in the position where the front end of the transfer paper is detached from the photosensitive body by electrification of the transfer paper itself after transfer and rigidity of the transfer paper. CONSTITUTION:A transfer paper 2 is guided to a photosensitive body 1 from a transfer guide 6 by a pair of carrying rolls 16 and is brought closely into contact with the photosensitive body 1 electrostatically, and a toner image is transferred by a charger 10 for electrification and transfer. The front end of the transfer paper 2 goes straightly by rigidity of the paper itself; and when it is detached naturally from the photosensitive body 1 in a curve part of a photosensitive body following-up roll 1b, the front end of the transfer paper 2 is brought into contact with a separation aiding belt 11, and the transfer paper is attracted electrostatically to the separation aiding belt 11 by the electric charge on the transfer paper 2 due to transfer. When the transfer paper 2 advances in the same speed as the photosensitive body 1 in this state, the transfer paper 2 reaches a fixing guide 12, and thus, the transfer paper 2 is separated from the photosensitive body 1.

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 charge 2/layer, those based on mechanical processing using a separation belt, and those using the above-mentioned separation charger and separation claw. Some use a combination of electrical and mechanical processing.

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 of the devices to easily separate this, a separation charger is provided separately from the transfer charger, and this removes the excess charge applied during transfer.
Page 3: A so-called electrostatic separation device is used, which is electrically treated so that the 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 AC (10) corona discharge, it is necessary to provide an AC high voltage power source.

On the other hand, in a separation belt device that processes separation mechanically, as shown in FIGS. 1 and 2, a transfer paper 2 guided to a photoreceptor drum 1 by a transfer guide 6 is exposed to light by an image forming means. The toner image formed on the surface of the body drum 1 is transferred by a transfer charger 5. 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, progressing at the same speed as the photoreceptor drum 1, and the transfer and separation are completed. It is done. 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 image is deleted from the edges of the copied image (the part held by the separation belt), and there is a drawback that the entire image cannot be copied.

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 a transfer paper 2 guided to a photoreceptor drum 1 by a transfer charger 5. and then separated by a separation charger 7. However, the force that separates the transfer paper 2 from the photoreceptor drum 1 tends to change depending on the surrounding environmental conditions such as humidity.
There are times when the transfer paper 2 is not separated from the photoreceptor drum 1 to a sufficient degree, or when it is not separated at all.

At these times, the transfer paper 2 is separated from the photosensitive six-page drum 1 by the separation 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.

As a device to solve the above problems, a belt-shaped photoconductor 1 is provided with a fourth separation device that separates the transfer paper from the photoconductor without using a separation charger, a separation belt, or a separation claw.
A toner image formed on the surface of the belt paper photoreceptor 1 by the image forming means is transferred to the transfer paper 2 guided by the transfer charger 6 . The leading edge of the transferred transfer paper advances to the photoconductor driven roller 1b. At this time, transfer paper 2
The leading edge of the paper 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 of the 6th page, the leading edge of the transfer paper 2 and The belt-shaped photoreceptors 1 that are 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 attracted to the belt-shaped photoreceptor 1 again.

A device that cleverly utilizes the phenomenon described above is an electrostatic adsorption separation device. The separation aid 9'lf: is placed at the position where the transfer paper 2 separates from the photoconductor 1, and the leading edge of the transfer paper 2 is brought into contact with the separation aid 9, so that the transfer paper 2 is electrostatically attracted by its own charge after transfer. There is a device that uses force to adsorb the separation aid material 9 and separate it. 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. This toner stain causes toner stains on the back side of the transfer paper when the transfer paper is separated, so there is a problem that double-sided copying cannot be performed using the front and back sides of the transfer paper.

OBJECTS OF THE INVENTION An object of the present invention is to provide a transfer paper separation device that separates transfer paper from a photoreceptor without using a separation charger, a separation belt, or a separation claw, and that realizes full-scale copying of images and high-quality double-sided copying. This is what we provide.

Structure of the Invention The transfer paper separation device of the present invention has a separation assisting belt disposed at a position where the leading edge of the transfer paper separates from the photoconductor due to the charging of the transfer paper itself after transfer and the rigidity of the transfer paper in the photoconductor roll portion. The transfer paper is separated from the belt-shaped photoreceptor by bringing the leading edge of the transfer paper into contact with the separation auxiliary belt, and the separation belt is equipped with a cleaning mechanism to remove adhered toner stains. This enables stable separation of the transfer paper, making it possible to copy the entire image, and to prevent toner stains on the back side of the transfer paper, making it possible to perform high-quality double-sided copying. It is something that

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

FIG. 5 shows a schematic diagram of the main parts of a copying machine to which the transfer paper separating device of the present invention is applied. In Figure 5, 1 is OP
Belt-shaped photoreceptor (hereinafter referred to as
14 is a 120 mπφ photoconductor driving drum, 1b is a 30 mm φ photoconductor driven roller, 2 is a transfer paper,
6 is a transfer guide, 1o is a charging and transfer charger,
11 is a separation auxiliary belt having a width of 270 mm and is made of a polyester film with a thickness of 70 pm and has aluminum vapor-deposited with a thickness of 1 μm on the surface; 12 is a fixing guide; 13 is a cleaning brush for removing toner adhesion stains from the separation auxiliary belt; 14 is the cassette containing transfer paper 2, 1
5 is a feed roller, 16 is a pair of transport rollers, 17 is a fixing device, 18 is a developing device, 19 is an exposure device including an optical fiber lens 192L and a lamp 19b, 2o is a photoconductor cleaning device, and 21 is a photoconductor static eliminator. lamp, 22
is a 9-page 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 .

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. The separation auxiliary belt 11 is placed at this location and rotated in synchronization with the photoreceptor drive drum 11. Said transfer paper 2
The leading edge of the paper 2 contacts the separation auxiliary belt 11 and is electrostatically attracted to the separation auxiliary belt 11 due to the charge that is generated on the transfer paper 2 by the transfer. In this state, when the transfer paper 2 advances at the same speed as the photoreceptor 1, it reaches the fixing guide and is separated from the photoreceptor 1. Further, the separation auxiliary belt 11 rotates by 10 degrees while the photoreceptor driving drum 1a is being driven, and the cleaning brush 13, which is disposed in contact with the separation auxiliary belt 11, is driven by the photoreceptor driving drum 1a. The separation auxiliary belt 11 is rotated during this time to remove toner attached to the separation auxiliary belt 11. In the above embodiment, the material of the separation auxiliary belt was based on a polyester film, and aluminum was used on its surface, but the material is not limited to aluminum, and the material is electrostatically attracted to the transfer paper by the electric charge. Any material can be used as long as it has this function, and for example, copper, nickel, gold, etc. can be used alone or in combination.

Effects of the Invention As is clear from the invention described above, the present invention is a device for separating a transfer paper from a photoreceptor. Since the separation auxiliary belt roller is arranged at the position where the leading edge of the paper comes off, and the leading edge of the transfer paper is brought into contact with the separation auxiliary belt, there is no need for a conventional separation charger, AC power supply, etc. In addition, since there is no need for a mechanically forced separation device such as a separation belt 11 or separation claws, it is possible to copy the entire image, and there is no problem of separation claw marks. Furthermore, if the separation auxiliary belt of the present invention has a cleaning mechanism for removing adhered toner stains, toner stains will not occur on the back side of the transfer paper after separation, making double-sided copying possible using the front and back sides of the transfer paper. can do.

[Brief explanation of drawings]

Figure 1 is a perspective view of the main parts of the conventional device, Figure 2 is its side view,
3 and 4 are side views of another conventional device, and FIG. 6 is a schematic diagram of main parts of a copying machine to which an embodiment of the present invention is applied.
7 and 7 are side views of one embodiment of the present invention. 1... Belt-shaped photoreceptor, 1b... Photoreceptor driven roller, 11... Separation auxiliary belt, 1
3...Cleaning brush. Name of agent: Patent attorney Toshio Nakao and 1 other person @1
Figure A Figure 2 Figure 3 ( Figure 4 Figure 5

Claims (2)

[Claims] (1) A separation auxiliary belt is placed at a position where the leading edge of the transfer paper separates from the photoconductor due to the charging of the transfer paper itself after transfer and the rigidity of the transfer paper in the photoconductor roll portion, and the leading edge of the transfer paper is separated. A transfer paper separation device characterized in that the transfer paper separation device is configured to separate the transfer paper from the belt-shaped photoreceptor by bringing the transfer paper into contact with an auxiliary belt. (2) Claim No. 1 states that the separation auxiliary belt has a cleaning mechanism for removing attached toner stains.
Transfer paper separation device described in ).