JPS6090371A - Transfer paper separating device - Google Patents

Abstract

PURPOSE:To separate exactly a transfer paper without using a separating pawl by constituting so that a charge whose polarity is opposite to the transfer paper is induced in a separating subsidiary material in the vicinity of a photosensitive body, and the transfer paper is attracted electrostatically. CONSTITUTION:As for a separating subsidiary material 10 on a production of a contact (a) of a transfer paper 2 and a photosensitive roll 1b, when the transfer paper 2 approaches, a positive charge whose polarity is opposite to the paper 2 is induced in the subsidiary material 10 by a charge of the transfer paper itself, and the paper 2 is attructed electrostatically and separated from a photosensitive body 1. The photosensitive body side of the subsidiary material 10 is bent in a chevron shape, the opposite side is made long enough, and a gap (h) to the roll 1b in a point (e) is set to <=1mm.. Accordingly, the transfer paper can be separated stably by a simple constitution without using a separating pawl, etc.

Description

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

Structures of conventional examples and their problems Conventional transfer paper separation devices include one based on electrical processing using a separation charger, one based on mechanical processing using a separation belt, and one based on electrical processing using the above-mentioned separation charger and splitting claw. There are also those that use mechanical treatment.

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, the transfer paper has an extra charge of opposite polarity to the toner due to the corona discharge for the transfer. , 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.
A so-called electrostatic separation device is used, which is electrically treated 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 AC (alternating current fi) 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, the transfer paper 2 guided to the photoreceptor drum 1 by the transfer guide 6 is moved by the image forming means. The toner image formed on the surface of the photosensitive drum 10 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 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 edge of the transfer paper held by the separation belt exists separately from the image area. The disadvantage is that the image has been deleted from the area (part) and cannot be copied in its entirety.

In addition, there is another separation device that uses a separation charger and a separation claw in combination. This device uses a transfer guide 6 as shown in Fig. 3.
The toner image formed on the surface of the photoreceptor drum 10 by the image forming means is transferred to the transfer paper 2 guided by the photoreceptor drum 1 by transfer charges . -7. However, the force that separates the transfer paper 2 from the photoreceptor drum 1 tends to change depending on ambient environmental conditions such as humidity.If the degree of separation of the transfer paper 2 from the photoreceptor drum 1 is not sufficient, there are times when the transfer paper 2 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.

However, in this case, the unfixed toner image held on the surface of the transfer paper 20 is rubbed when it comes into contact with the separation claw 8,
There is a drawback that traces are 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 charger, separation belt, or separation claw.

Structure of the Invention In the transfer paper separation device of the present invention, a separation auxiliary material is disposed near the photoreceptor roll portion, and when the transfer paper after transfer approaches the separation auxiliary phase, the transfer paper is separated by its own electric charge. A charge having a polarity opposite to that of the charge is induced in the separation auxiliary material, and the transfer paper is electrostatically attracted to the separation auxiliary material, thereby separating the transfer paper from the photoreceptor. Further, the separation auxiliary material includes at least the straight line with a limit on the straight line connecting the contact point between the photoreceptor roll part and the transfer paper after transfer,
By arranging it so as to be located on the rotational direction side of the photoreceptor roll, it is possible to stably separate the transfer paper with a simple structure, and it is also 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 photoreceptor (hereinafter referred to as photoreceptor) using an organic photoconductor, 1a is a photoreceptor driving drum, and 1b is a photoreceptor driven roll (hereinafter referred to as photoreceptor roll). , 2 is a transfer paper, 6 is a transfer guide, 9 is a charger for both charging and transfer, 10
11 (lJ) is a cassette containing the transfer paper 2; 12 is a feed roller; 13 is a pair of transport rollers; 14 is a developing device; 16 is an optical fiber lens 15a and a lamp. 15b is an exposure device, 16 is a photoconductor cleaning device, 17 is a photoconductor discharge lamp, 1B 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. 5 is sent to the transfer guide 6 by a pair of transport rollers (not shown). Next, the transfer paper 2 is guided to the photoreceptor 1 , is brought into close contact with the photoreceptor 1 electrostatically, and the toner image formed on the photoreceptor 1 is transferred by charging with negative polarity corona discharge and a transfer charger 9 .

The surface of the separation aid 10 made of a stainless steel plate having a thickness o and swL is placed so that the surface thereof is located above the extension line of the tangent to the contact point A between the transfer paper 2 and the photoreceptor roll 16, which is indicated by a broken line in FIG. The transfer paper 2 after transfer advances at the same speed as the photoreceptor 1, and the leading edge of the transfer paper 2 approaches the separation auxiliary phase 10.
By the way, the toner image on the photoreceptor 1 is transferred to the transfer paper 2 in 11I by a negative transfer charger (not shown), and as a result, the transfer paper 2 is negatively charged with an excess of negative charge. As the transfer paper 2 approaches the separation auxiliary phase 1o, a positive charge with the opposite polarity to that of the transfer paper 2 is induced in the separation auxiliary material 1o, which attracts each other electrostatically, and as a result, the transfer paper 2 becomes the separation auxiliary phase 1o. Adsorbed to phase 10.

Separation of the transfer paper 2 from the photoreceptor 1 is started, and the transfer paper 2 further advances and is guided to the fixing device 18, where it is fixed and the separation is completed. Furthermore, the sixth most suitable condition for the present invention is
As shown in the figure, the tip shape of the separation auxiliary phase 10 on the side of the photoreceptor roll is bent into a dogleg shape to connect the photoreceptor roll 1b and the transfer paper 2.
The extension line of the tangent of contact point A should be sufficiently long from the opening to the side opposite to the rotational direction of the photoreceptor roll 1b, and be longer than the point A. If this treatment is not performed, there is a risk that the transfer paper 2 will plunge into the underside of the separation auxiliary phase 10 during separation. In addition, the practical gap between the point E, which contributes to the separation of the separation aid 1o, and the intersection point G between the photoreceptor 1 and the line connecting the center I and gold of the photoreceptor roll 1b is less than 1 mm. be.

By setting the shape of the separation auxiliary material 10 and the gap from the photoreceptor to the optimum conditions as described above, even in other embodiments, the photoreceptor 1 can be attached to the photoreceptor roll 1b as shown in FIG.
Apply the separation aid 1o at least one place or continuously to the extended line and the area of the contact points C and 2, respectively, and apply the separation aid 10 to the photoreceptor with a gap of 1 inch or less, and then transfer the transfer paper. 2 is guided to the fixing device 1B, it is possible to separate the transfer paper in the same way as in the embodiment of the invention shown in FIGS. 6 and 6. In the examples of the present invention, a plate made of stainless steel was used as the separation auxiliary material, but the material is not limited to a plate, and similar results can be obtained even if a round bar is used. Also, it is not limited to stainless steel materials.

Any conductive material may be used, such as aluminum, copper, etc.

Effects of the Invention As is clear from the above explanation, in the present invention, a separation aid is arranged near the photoreceptor roll portion, and when the transfer paper after transfer comes close to the separation aid, the charge of the transfer paper itself causes A charge having a polarity opposite to that of the transfer paper is induced in the separation auxiliary material, and the transfer paper is electrostatically attracted to the separation auxiliary material to separate the transfer paper from the photoreceptor, and
The separation auxiliary material is stabilized by being placed on the straight line connecting the contact point between the photoreceptor roll and the transfer paper after transfer, including at least the straight line, and positioned on the rotational direction side of the photoreceptor roll. Separation of the transfer paper can be realized, which simplifies the configuration of the copying machine and allows full copying of images.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional transfer paper separation device, FIG. 2 is a side view thereof, and FIG. 3 is a side view of another example of a conventional transfer paper separation device.
FIG. 4 is a schematic diagram of a copying machine to which an embodiment of the present invention is applied;
FIG. 5 is a side view of essential parts of an example of the transfer paper separation device of the present invention;
FIG. 6 is an enlarged side view of the main part thereof, and FIG. 7 is a side view of the main part of another embodiment of the transfer paper separating device of the present invention. 1...Photoconductor, 1b...Photoconductor roll,
10...Separation auxiliary material, 18...Fixing device. Name of agent: Patent attorney Toshio Nakao and 1 other person! i
l1Figure 2Figure 3Figure 4Figure 5Figure 6

Claims (1)

[Claims] (1) A separation aid is placed near the photoreceptor roll, and as the transfer paper approaches the separation aid after transfer, the charge of the transfer paper itself causes the charge of opposite polarity to the charge of the transfer paper to rise above. A transfer paper separation device configured to electrostatically attract the transfer paper to the separation aid material and separate the transfer paper from the photoreceptor. (No. The separation auxiliary material is disposed so as to include at least the straight line connecting the contact point between the photoreceptor roll and the transfer paper after transfer, and to be located on the rotational direction side of the photoreceptor roll. Claim No. (1) characterized in that
Transfer paper separation device described in Section 1.