JPS6090372A - Transfer paper separating device - Google Patents

Abstract

PURPOSE:To separate exactly a transfer paper without a separating pawl, etc. by constituting so that the tip of a transfer paper is made to contact to a separating subsidiary material and separated from a photosensitive body, by an electrostatic charge and a rigidity of the transfer paper itself. CONSTITUTION:The tip of a carried transfer paper 2 is separated a little from a photosensitive body 1 in a curved part of a driven roller 1b of the photosensitive body, and when it contacts to a rod-like separating subsidiary material 10, it is attracted electrostatically to the subsidiary material 10 by a charge electrostatically charged to the transfer paper 2. The transfer paper 2 reaches a fixing guide 11, also adheres tightly electrostatically, and it is separated exactly from the photosensitive body 1. A diameter of the driven roller 1b is within a range of 20-40mm., and there is an effect for separating the transfer paper from the curved part of the roller by a rigidity of the paper. Accordingly, since an electrostatic charge and a rigidity of the transfer paper itself are utilized, an AC high voltage power source, etc. become unnecessary, and since no separating pawl is used, the whole surface copying of an image can be executed, the photosensitive body is not damaged, and the transfer paper 2 can be separated exactly by a simple constitution.

Description

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

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 using electrical processing using the above-mentioned separation charger and separation claws. Some use mechanical processing in combination.

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 a corona discharge to the transfer paper with a polarity opposite to the charge held by the toner, thereby transferring the toner image on the photoreceptor onto the transfer paper. Next, when the transfer paper on which the toner image has been transferred is separated from the surface of the photoreceptor, there is an extra charge on the transfer paper with the opposite polarity to that of the toner due to the corona discharge in the transfer chamber. 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, and the stiffness t1' of the transfer paper and its own weight naturally cause the photoreceptor to move. A so-called electrostatic separation device is used, which is electrically processed to separate the particles from the particles. 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 (alternating current) 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. The toner image formed on the surface of the photoreceptor drum 1 is transferred by the transfer charger 6 ◇At this time, one end A on one side of the transfer paper 2 is held between the separation belt 3 and the separation roller 4 to prevent the transfer of the photoreceptor drum 1. The transfer paper 2 advances along the end of the conveyance path in a state where the end of the transfer paper 2 that is outside the image area does not come into contact with 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 located on the photosensitive drum 1.
While in contact with the photosensitive drum 1, the toner image is transferred by the transfer charger 5 and advances at the same speed as the photosensitive drum 1,
Transfer and separation takes place.

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 photoreceptor drum 1 by the separating claw 8 in the direction of the arrow as shown by the dashed line. but,
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.

OBJECTS OF THE INVENTION An object of the present invention is to provide a transfer paper separation device that reliably separates transfer paper from a photoreceptor without using a separation charge-1 separation belt or a separation claw.

Structure of the Invention The transfer paper separation device of the present invention includes a separation aid that is arranged 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 configured to be separated from the belt-shaped photoreceptor by bringing the leading edge of the transfer paper into contact with the separation auxiliary material, thereby enabling stable transfer paper separation and simplifying the copying machine mechanism. This makes it possible to copy the entire image.

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

FIG. 4 shows a schematic diagram of a copying machine to which the transfer paper separating device of the present invention is applied. In Fig. 4, 1 is an endless belt-shaped photoconductor using an organic photoconductor, and 1a is a diameter of 12 mm.
0-φ photoreceptor drive drum, 1b has a diameter of 20 tanφ
2 is a transfer machine, 6 is a transfer guide,
9 is a charging and transfer charger, 1o is a separation aid, 11 is a fixing guide, 12 is a cassette containing the transfer paper 2, 13 is a feed roller, 14 is a pair of transport rollers, 16 is a developer, and 16 is an optical An exposure device includes a fiber lens 16a and a lamp 16b, 17 is a cleaning device, 18 is a photoreceptor static elimination lamp, 19 is a fixing device, and 2o 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 14.

Next, the transfer paper 2 is guided to the belt-shaped photoreceptor 1 and is electrostatically brought into close contact with the belt-shaped photoreceptor 1, and the toner image formed on the belt-shaped photoreceptor 1 is transferred by a charging and transfer charger 9. The leading edge of the transfer paper 2, indicated by a broken line in FIG. 6, naturally separates slightly from the belt-shaped photoreceptor 1 at the curved portion of the photoreceptor driven roller 1b due to the rigidity of the paper. By placing the rod-shaped separation auxiliary phase 10 at this location, the tip of the transfer paper 2 comes into contact with the separation auxiliary material 10 at point A, and the transfer paper 2 is electrostatically connected to the separation auxiliary material 10 due to the electrical charge. adsorbs to. In this state, when the transfer paper 2 advances at the same speed as the photoconductor 1, it reaches the fixing guide 11 as shown by the dashed-dotted arrow, and is further electrostatically adhered to it, causing the transfer paper 2 to separate from the photoconductor 1. This makes it possible to achieve stable transfer paper separation.

The material of the separation auxiliary material 1o of the present invention is not particularly limited as long as it can be electrostatically attracted to the transfer paper 2. In this example, an aluminum rod with a diameter of 10n+mφ was used. By the way, when the separation auxiliary material 1o is not arranged, there is a probability that the leading edge of the transfer paper 2 will be slightly separated from the photoconductor 1 and then be attracted to the photoconductor 1 again due to electrostatic force, resulting in defective transfer paper separation. It increases. This development is particularly noticeable on thin transfer paper. As can be seen from this, the apparatus of the present invention is particularly effective when using thin transfer paper. Furthermore, the most suitable condition for the present invention is that the smaller the diameter of the photoreceptor driven roller, the more force due to the rigidity of the transfer paper is generated in the photoreceptor driven roller portion than the force caused by the transfer paper being in close contact with the photoreceptor. If it is relatively strong, the transfer paper will easily separate from the photoreceptor. However, if the diameter of the photoreceptor driven roller is too small, the photoreceptor itself may crack or be permanently deformed, which may affect the copied image. In experiments in the present invention, the lower limit of the diameter of the photoreceptor driven roller, which poses no practical problem, was 20 rrmφ. On the other hand, the upper limit of the diameter of the photoconductor driven roller is 40mmφ.
When the diameter is made larger than IIφ, the force due to the rigidity of the transfer paper is inferior to the adsorption force between the photoreceptor and the transfer paper. In other words, since the leading edge of the transfer paper follows changes in the curvature of the photoreceptor roller portion, separation of the photoreceptor and the transfer paper becomes difficult to occur, and the separation performance deteriorates depending on the surrounding environment. Therefore, the diameter of the photoreceptor driven roller portion that can be used in the transfer paper separation device of the present invention without causing any practical problems is 20 to 40 cylinders φ.

Next, other embodiments of the present invention will be described with reference to the drawings.

FIG. 7 is a side view of a transfer paper separating device in another embodiment of the present invention. In FIG. 7, the toner image formed on the belt-shaped photoreceptor 1 is transferred to the transfer paper 2, and the leading edge of the transfer paper 2, indicated by a broken line, is moved to the photoreceptor driven roller 1 due to the rigidity of the paper.
In b, it is naturally separated from the belt-shaped photoreceptor 1, albeit slightly. A plate-shaped separation auxiliary side 10 made of stainless steel is placed at this location. This arrangement position is, in FIG. 7, the center of the driven roller part is below the perpendicular line 2; ~, on the extension line in the traveling direction of the transfer paper after transfer -c1 is a point W1 = 6 m from the point E that is orthogonal to this perpendicular line. is the point A. Connect this point A and the roller center C to a straight line, and draw a parallel line parallel to the tangent line Q at the intersection of this line and the roller outer circumference, passing through point A, and separate it on a parallel line υ. Arrange the auxiliary material 1o.

In addition, the size of this separation aid 1o on the parallel line υ is sufficiently larger than the width of Wl and W2, respectively, centered on point A, which greatly contributes to separation of the transfer paper, as shown in FIG. put. In addition, the dots parallel to the other end of the separation aid 1'10, that is, the dots between the two ends, have the function of the fixing guide 11 shown in FIG. 6 in the above embodiment. The separation aid 10 and the fixing guide 11 are integrated. Therefore, by arranging the separation auxiliary material 10 in FIG. 7, the leading edge of the transfer paper 2 comes into contact with the separation auxiliary side 10 at point A, as in the previous embodiment, and the transfer paper 2 is electrically charged. It electrostatically adsorbs to the separation auxiliary material 10. In this state, when the transfer paper 2 advances at the same speed as the photoreceptor 1, as shown by the dashed-dotted arrow, the transfer paper 2 is moved further and electrostatically attracted to the transfer paper 2, thereby achieving a more stable separation of the transfer paper. Similar to the above embodiment, the present invention has a photoreceptor driven roller diameter of 20ttanφ to 40ranφ,
This makes it possible to separate the transfer paper without causing any practical problems.

Effects of the Invention As is clear from the above explanation, the present invention is a device for separating transfer paper from a photoconductor, which utilizes the charging of the transfer paper itself after transfer and the rigidity of the transfer paper in the photoconductor roll portion, and separates the transfer paper from the photoconductor. A separation auxiliary material is placed at a position where the leading edge of the transfer paper is separated from the auxiliary material, and when the leading edge of the transfer paper comes into contact with this auxiliary material, it is electrostatically attracted and separated. This eliminates the need for an AC high-voltage power supply, making the copying machine structure simpler and more compact than a VC. Furthermore, since no separation belt or separation claw is required, the entire image can be copied, and a high-quality image without separation claw marks can be obtained. Further, the problem of scratching the photoreceptor with the separation claw and damaging the photoreceptor is also eliminated.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional transfer paper separation device, FIG. 2 is a side view thereof, FIG. 3 is a side view of another example of the conventional transfer paper separation device, and FIG. 4 is an embodiment of the present invention. FIG. 5 is a side view of the main parts thereof, and FIGS. 6 and 7 are side views of the main parts of an embodiment of the present invention. 1... Belt-shaped photoconductor, 1b... Photoconductor driven roller, 10... Separation auxiliary material, 11 Fixing guide 0 Name of agent: Patent attorney Toshio Nakao and 1 other person 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 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 separation aid A transfer paper separating device configured to separate a transfer paper from a belt-shaped photoreceptor by bringing it into contact with the belt-shaped photoreceptor. (2) The diameter of the photoconductor driven roller in the photoconductor roll section is 2
The transfer paper separation device according to claim (1), characterized in that o■φ to 40++II+Iφ.