JPS60125871A - Transfer paper separating device - Google Patents

Abstract

PURPOSE:To take an entire-surface copy of an image and a both-surface copy of high quality by bringing the front end of transfer paper into contact with the projection plate of a separation auxiliary roller where the transfer paper leaves a photosensitive body, and separating the transfer paper from the photosensitive body by the rotation of the roller. CONSTITUTION:The transfer paper 2 contacts the projection plate 11a of the separation auxiliary roller 11 where it moves forth along a photosensitive body belt 1 and its front edge is separated at the curved part of the driven roller 1b of the photosensitive body by the stiffness of the paper, and the transfer paper 2 is attracted to the projection plate 11a by charge, charged electrostatically, thereby separating the transfer paper 2 from the photosensitive body 1 by the rotation of the roller 11. Therefore, a separation charger is unnecessary and the need for a separation pawl, etc., is eliminated, so an entire-surface copy of an image is taken; and the auxiliary roller 11 rotates only during the separating operation, so the problem of toner sticking is solved to eliminate toner staining, thereby taking a both-surface copy of high quality.

Description

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

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

Generally, in an electrophotographic copying apparatus, a photoreceptor formed in the shape of a drum or belt is charged with a charging charger and exposed to light to form an electrostatic latent image. Develop this with toner,
With the transfer paper in contact with the developing surface, a transfer charger performs a corona discharge on the transfer paper with the opposite polarity to the charge held by 1.S- to transfer the developed toner image on the photoreceptor to the transfer paper. let Next, when the transfer paper on which the toner image has been transferred is separated from the photoreceptor surface, an extra charge of the toner (!: is the opposite polarity) is present on the transfer paper due to the corona discharge for the transfer. Because of this electrostatic attraction, the transfer paper is attracted to the photoreceptor. This makes it difficult to separate the transfer paper from the photoreceptor. One device that can easily separate this is a transfer charger. A separation charger is installed separately, and this removes the excess charge applied during transfer.This is a so-called electrostatic separation device that is electrically treated so that the transfer paper naturally separates from the photoreceptor due to its rigidity and weight. It is used.

As described above, in the electrostatic separation device, a separation charger must be provided separately from the transfer charge V-. Furthermore, since the separation charger uses alternating current (AC) corona discharge, it is necessary to provide an AC high voltage power source.

The separation belt device that mechanically handles the separation is as follows: As shown in FIGS.
The toner image formed on the surface of the photoreceptor drum 1 by the image forming means is transferred by the transfer charger 5. At this time, one end of one side of the transfer paper 2 is separated by a belt 3.
A photosensitive drum 1 is sandwiched between a separation roller 4 and a separation roller 4.
The transfer paper 2 moves along the end of the transfer material conveyance path with the end of the transfer paper 2 that is away from the image area barely touching the photoreceptor drum 1. While the portion is in contact with the photoreceptor drum 1, the toner image is transferred by the transfer charger 6 and advances at the same speed as the photoreceptor drum 1, thereby performing one transfer and separation. 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 (portions held by the separation belt) are deleted, and the entire image cannot be copied. Another separation device uses a separation charger and a minute μiI claw. 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 6. It is first separated by a separation charger 7. However, since the force for separating the transfer paper 2 from the photoreceptor drum 1 tends 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 when it 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 undefined toner image held on the front side of the transfer paper 2 is rubbed when it comes into contact with the separating claw 8, and the marks are left behind on the toner image. Furthermore, there is a problem that the separating claw constantly contacts the photoreceptor, causing scratches on the surface of the photoreceptor that it is rubbing against.

A separation charger is used as a device to solve problems such as 1 and 1. A separation device that separates transfer paper from a photoreceptor without using a separation belt or a separation claw is a transfer paper separation device shown in Fig. 4. As shown in FIG. 4, an image is formed on the transfer paper 2 guided by the transfer guide 6 to the belt-like photoreceptor 1 in contact with the photoreceptor driving drum 12L. ．． The transferred toner image is transferred by the transfer charger 5. 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 attempts to move straight due to the rigidity of the paper, but the belt-like sensitive body 1 that is in contact with the leading edge of the transfer paper 2 changes due to the curvature of the photoconductor driven roller 1b, resulting in [7] The belt-shaped photoreceptor 1 in contact with the leading edge and the edge of the transfer paper 2 separates in a very short time.

As the transfer paper 2 further advances, the electrostatic adsorption force on the photoreceptor 1 due to the electric charges charged on the transfer paper 2 at 1 o'clock becomes relatively electrostatic adsorption, partly because the force due to the rigidity of the transfer paper 2 weakens. The power is strong.

The transfer paper 2 is adsorbed onto the belt-shaped photoreceptor 1 again. 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 separates from the belt-like photoreceptor 1 in a short period of time depending on the curvature of the photoreceptor and the rigidity of the transfer paper 2, and the leading edge of the transfer paper 2 is attached to the separation aid 9. There is a device in which the transfer paper 2 is brought into contact with the transfer paper 2 after one transfer, and the transfer paper 2 is attracted to and separated from the first parting auxiliary layer 9 by the electrostatic adhesion force generated by the belt mechanism. However, with this device, the separation auxiliary material 9 adheres to the surface of the separation auxiliary phase as dirt due to toner scattering within the copying machine. This 1.Stain causes toner stains on the back side of the transfer paper when the transfer paper is separated, so there is a problem in that double-sided copying using the front and back sides of the transfer paper is not possible. Furthermore, in order to solve this problem, it is necessary to rotate the separation auxiliary material and also provide cleaning means such as not allowing the cleaning brush to come into contact with the separation auxiliary material, resulting in a complex configuration of the copying machine. There are problems such as.

OBJECTS OF THE INVENTION The object of the present invention is to provide a transfer paper separation device which separates transfer paper from a photoreceptor without using a separation charger, separation belt, or separation claw, and which realizes full-scale copying of one image and high-quality double-sided copying. It provides:

Structure of the Invention The transfer paper separation device of the present invention has a protruding plate at a position where the transfer paper is separated from the photoconductor due to the charging of the transfer material after one transfer and the bulge of the transfer paper at the photoconductor roll portion. An auxiliary roller is arranged, and the protruding base is located in the same direction as the traveling direction of the transfer paper, so that the leading edge of the transfer paper after transfer reaches the photoreceptor roll, and the protrusion plate is placed before the photoreceptor roll. After the leading edge of the transfer paper contacts the protruding plate after one transfer, the transfer paper is separated from the photoconductor by rotating the separation auxiliary roller for one time.This allows stable separation of the transfer paper. It is possible to make a full-page copy of one image, and high-quality double-sided copying is possible because the back side of the transfer paper does not get stained with toner. This will be explained with reference to.

FIG. 5 is a schematic diagram of an example of a copying machine to which the transfer paper separator # of the present invention is applied. In Figure 5, 1 is OP
Belt-shaped photoreceptor (hereinafter referred to as
It is traveling at a speed of 160 mm/sec. 1a is a 120 mm x 1φ photoconductor driving drum, 1b is a 30 mmφ photoconductor driven roller 2, transfer paper 6 is a transfer guide, 10 is a charging and transfer charger (hereinafter referred to as
Charger)-11 has a diameter of 10 nm and a width of 270 mm, and is accompanied by a protruding plate 11a made of aluminum with a thickness of 0.2 mm, a height of 2 mm, and a width of 270 ff1 m.
The rotatable shaft 12 of the aluminum bar separation auxiliary roller 11b drives the separation auxiliary roller 11.The electromagnetic switch 12 and the spring 13 with a built-in electromagnetic switch connect the separation auxiliary roller 11 and the electromagnetic switch. A shaft directly connected to the drive unit, 14 a fixing guide, 16 a cassette 16 storing the transfer paper 2, a feeding roller 17 a pair of transport rollers, 18 a fixing product.
19 is the developed product - 20 is the optical system optical fiber lens 20 &
and a lamp 20b, 21 is a photoconductor cleaning device, 22 is a photoconductor static elimination lamp, and 23 is a paper discharge tray.

The operation of the transfer paper separating device of this embodiment constructed 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 charger 10 for charging and aging.

At this time, the charger starts discharging (charger 1
0) At the same time, apply full voltage to the electromagnetic switch 12 and rotate the 1-separation auxiliary roller 11.
The tip of the roller 2L was placed at an angle of 32 degrees -1 in the direction of movement of the transfer paper 2 from the center perpendicular to the photoreceptor driven roller 1b. Photoreceptor 1 and projection plate 11? The gap between the tip of L and the tip is set close to each other by 0.7 mm. Due to the rigidity of the paper, the leading edge of the transfer paper 2, which is also indicated by a broken line in FIG.
At the curved portion, the transfer paper 2 naturally separates from the photoreceptor for an instant. Since the protrusion plate 11a of the separation auxiliary roller 11 is arranged at this location, the tip of the transfer paper 2 contacts the protrusion plate 112L and is electrostatically connected to the protrusion plate 11a due to the electric charge charged on the transfer paper 2 by one transfer. Adsorb.

In the unlikely event that the photoreceptor is traveling at a speed of 160 mm/sec,
The distance between the charger 1o and the photoreceptor driven roller 1b at the center part is set to a1esomm. I cut it. The distance from the center of the photoconductor driven roller 1b to the end of the fixing guide 14 (set to 4 ismm).Therefore, - the distance from the charger 10 to the fixing guide 14 [
It is 165mm.

The time it takes for the transfer paper 2 to travel this distance is 1.1 seconds.

The transfer paper 2 is transferred by the charger 10; at the same time as the transfer starts, voltage is applied to the electromagnetic switch and the separation auxiliary roller 1 is transferred.
1 and rotate the protruding plate 11B to the photoconductor driven roller 1b.
The transfer paper 2 moves forward and comes into contact with the protrusions 1fy and 11a and is attracted to them.

Next, when the voltage applied to the electromagnetic switch is cut off 1.1 seconds after the start of transfer, the separation auxiliary roller 11 rotates while the transfer paper 2 is attracted to the protrusion plate 111L, and the tip of the transfer paper 2 and the protrusion plate are rotated. iia moves away from the photoreceptor and the transfer paper is separated. The transfer paper 2 further advances and reaches the fixing guide 14 as shown by the dashed line A in FIG. 7, thereby ensuring separation.

Although aluminum was used for the protrusion plate in the two examples, it is not limited to aluminum; any material may be used as long as it has the function of electrostatically adhering to the transfer paper by the electric charge. For example, stainless steel, brass, etc. can be used.

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. A separation auxiliary roller having a protruding plate is disposed at a position where the transfer paper leaves the transfer paper, and one is located on the protrusion plate in the same direction as the traveling direction of the transfer paper, and the leading edge of the transfer paper after transfer is placed on the photoreceptor roll portion. Before reaching the photoreceptor, the projection plate is rotated toward the photoreceptor roll portion, and after the leading edge of the transfer paper after one transfer comes into contact with the projection plate, the transfer paper is separated from the photoreceptor by rotating a separation auxiliary roller. This eliminates the need for a separate charger and AC power supply, which are required for conventional models.

In addition, since the one-separation belt and separation claws are not used for safety, one image can be completely copied, and the problem of one-separation claw marks is eliminated. Further, since the separation auxiliary roller is brought close to the photoconductor only when necessary for separation and kept away from the photoconductor at other times, toner adhesion from the surface of the photoconductor can be removed. This toner adhesion occurs when the copying machine forms a toner image on the photoconductor and there is a paper jam before or during the process of transferring the toner image to the transfer paper. Finally, turn on the power and enter the warm-up mode to make it ready to start copying.During this warming-up, the 1st image on the photoreceptor during the 1-sheet gym is cleaned. When the toner image approaches the separation aid 11, as in the conventional method, if the gap between the photoreceptor and the separation aid (O) remains close, the separation aid 11 will surely
-ner adhesion occurs. In the present invention, the separation auxiliary roller rotates only when separating the transfer paper to bring the protruding plate closer to the photoreceptor, thus solving the toner adhesion problem. 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 one transfer paper can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional device, FIG. 2 is a side view thereof, and FIGS. 3 and 4 are side views of other conventional devices. -dy 4 Jr.
/7; II inini * 1) 1 Ishi Hakori i' -
a a) - Schematic representation of an example; FIGS. 6 and 7 are side views of an embodiment of the invention; FIG. 1... Belt-shaped photoreceptor -1b... Photoreceptor driven roller, 11... Separation auxiliary roller -11&-
・・Protrusion plate, 12・・・Electromagnetic switch, 13・−・
-N￥ft0 Agent's name: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 @ 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] A separation auxiliary roller having a protruding plate is disposed 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.
is positioned in the same direction as the transfer paper traveling direction, and before the leading edge of the transfer paper after transfer reaches the photoreceptor roll, the protrusion plate rotates toward the photoreceptor roll, and the transfer paper after transfer is rotated toward the photoreceptor roll. A transfer paper separation device characterized in that the transfer paper is separated from the photoreceptor by rotating a separation auxiliary roller one minute after the tip contacts the protrusion plate.