JPS5993480A - Destaticization device - Google Patents

Abstract

PURPOSE:To separate a transfer material securely by using either or both of destaticization electrodes on both sides of a dielectric mesh screen according to a specific process. CONSTITUTION:The transfer material is gripped by a grip body 12 on the surface of a transfer material support drum 3 surrounded by the dielectric mesh screen and rotated on the surface of the drum 3. A toner image on a drum 1 is transferred to the transfer material at a transfer electrode 11 and the transfer material is attracted electrostatically to the screen by the potential difference between the screen and transfer material and then rotated while held in a semifixed state in several transfer processes for colors. Destaticization electrodes 8a and 8b are operated in the final transfer process to eliminate the attracting force between the screen and transfer material and the transfer material is separated by a separation pawl 9 extremely easily. In other transfer processes, only an outside electrode 8a operates to reduce or neutralize charges on its surface and the surface potential for the next transfer is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a static eliminator suitable for use in color image forming apparatuses such as color copying machines and printers, and particularly in transfer material supporting parts thereof.

An image forming method in which, for example, a color image is formed by transferring multiple types of developers (toners) of different colors onto a transfer material in a superimposed manner is to irradiate a document with white light and then use the reflected light to Images are sequentially formed on the surface of a traveling photoreceptor through multiple types of color separation filters, and synchronized with multiple developing units containing multiple types of toner of different colors and the photoreceptor placed near the photoreceptor. Usually, a moving transfer material is used to sequentially develop and transfer latent images corresponding to each color and then fix the images to obtain a color copy.

FIG. 1 is a schematic explanatory diagram showing such a means applied to a color copying machine, in which a cylindrical photoreceptor 1 is rotatably supported within a copying machine main body 10. As shown in FIG.

A document M is placed on the top surface of the copying machine, and a rung L that illuminates the bottom surface of the document and a first mirror M1 that receives reflected light are integrally arranged below the document M in the main body. These lamps L and first mirror M1 travel in the direction of arrow X to scan the document surface.

The reflected light that has reached the first mirror M1 forms an image on the surface of the photoreceptor 1 through the second mirror M2, the lens system C%6 mirror M3, and the 'fJ4 mirror M4, and is hidden on the previously charged surface. An image is formed, but a color separation filter F with ji number of filters is placed at a suitable location in this optical path to separate the reflected light into colors, so a color separation image corresponding to each filter is formed on the surface of the photoreceptor. will form an image.

1. Yellow, magenta, and yellow color toners are collected near the photoreceptor 1. The developing units 2Y, 2M, and 20 are used as cooperators, and furthermore, a cylindrical transfer material support drum 6 equipped with an anti-transfer screen is disposed on the downstream steel 1 in the rotational direction of the photoreceptor 1. and the transfer material in cassette 5 is 1-
The drum 3 is supported by the drum 3 via the wide feeding path 6, and rotates in synchronization with the photoreceptor 1.

The first color separation formed on the photosensitive material by one of the color separation filters is visualized by the image developer 2Y, and this image is developed on the transfer material supported by the drum 3. transcribed. Next, the color separated images formed on the surface of the photoreceptor 1 by the second and sixth filters are superimposed and transferred onto the permanent transfer material by the magenta developer 2M and the cyan developer 1#2C, respectively, from the drum 6. The image is released, passed through the conveyor belt 4, fixed by the fixing device 7, and then discharged outside the machine.

In fact, when making a color copy, the developer uses yellow, magenta, and
In addition to the cyan toner, it is common to add a toner containing black toner, and also have an endless belt-like transfer material support section with photoreceptors arranged in a series and close to this. This has been said before, but in any case, each transfer material has yellow, magenta, and cyan (and black) on the surface! ! This method is different from the conventional method in that it obtains a color image by transferring and fixing an L image onto a V-tatami mat.

In the case where multiple types of color separated images are formed in a superimposed manner, since the toner still has an electric charge even after the transfer of the first color is completed, when transferring the second color, the toner of the first color is The problem of insufficient transfer of the second color image due to the presence of charge on the toner has not been avoided. It goes without saying that the same problem exists in the transfer of the 5th and 4th color of 'ffJ.

In order to eliminate these drawbacks, the transfer potential for the second color image transfer is gradually increased from that for the first color image transfer, so that the transfer efficiency for all hues is kept constant. Some methods have been proposed to do so.

However, when such a method is used, the potential during final transfer is extremely high, and abnormal discharge from the transfer charger accelerates deterioration of the photoconductive layer and causes oxidation of the toner and air.
The durability of the photoreceptor may deteriorate due to 1m1 deposits of nitride, etc., white spots may appear on the transferred image, resulting in deterioration of copy image quality, or noise caused by leakage may adversely affect the control section of the device. I wasn't blinded.

Therefore, attempts have been made to reduce the transfer efficiency by eliminating static electricity from the transfer material and the dielectric mesh screen that mechanically and electrostatically supports it during the transfer process before the final transfer. Then, the electrostatic attractive force between the transfer material and the dielectric mesh screen weakens, and the transfer material is only mechanically supported by the gripper on the surface of the support drum. Since the support drum and the transfer material can be moved relative to each other, problems such as misalignment of the transfer position of each color toner may occur, and the transfer material may come into contact with other parts of the machine, causing blurred images. There was a risk that

The present invention has been made in view of the above-mentioned current situation, and in the portion where the dielectric mesh screen and the transfer material gripped and attracted by the screen are run together, the transfer material and the transfer material are attached to both sides of the screen. A pair of opposing static eliminating electrodes is arranged, and when the transfer process is in progress, the electrodes are output only on the side that carries the toner image to neutralize the charge on the core and prevent any hindrance to the next transfer. In addition to ensuring that
To provide a static eliminator capable of reliably separating a transfer material by outputting both electrodes after the final transfer process and reducing the electrostatic adhesion force between the transfer material and a mesh screen. This is the purpose.

FIG. 2 is a schematic explanatory diagram showing an embodiment of the present invention, which corresponds to the transfer section 6-1 of a color copying machine as shown in FIG.

When the transfer material taken out from the cassette 5 via the conveyance path 6 reaches the surface of the transfer material support drum 60 surrounded by a dielectric mesh screen, its tip is held by the gripper 12, and as the drum 6 rotates, it is The transfer moon is placed on the surface of the drum 60 and rotates.

Next, when the transfer material passes through a transfer site where the photoreceptor 1 and the drum 6 are close to each other and the transfer electrode 11 is provided, the toner image on the photoreceptor 1 is transferred to the transfer material, and the screen and the transfer material The transfer material is electrostatically attracted to the screen due to the potential difference between the transfer material and the screen, and the transfer material is maintained in a semi-fixed state and rotated during a plurality of subsequent transfer steps.

In such a transfer mechanism, as shown in Figure 2,
In the direction of rotation of the drum 30, on the downstream side of the transfer electrode, two static eliminating electrodes 8a and 3b are disposed facing each other so as to sandwich the dielectric mesh screen.
AC voltage is applied with the phase shifted. In order to carry out multiple transfers while carrying the transfer material, when the transfer material is passed through the transfer electrode a number of times, when the transfer process prior to the final transfer process is completed, the static electricity is removed as described above. polar 8a, f3
Only the electrode 8a facing the outer side of b, that is, the surface carrying the toner image, is output to reduce or neutralize the charge in the core portion and adjust its surface potential in preparation for the next transfer.

At this time, since the electrode 8b remains deenergized, the surface charge of the screen remains, and thereby the adsorption effect of the transfer material to the screen is also maintained.

When the transfer material reaches the positions of the electrodes 3a and 8b after the final transfer step, both the electrodes 13a and 8b are outputted together, thereby losing the adhesion force between the screen and the transfer material, so the gripper 12 is released. The transfer material can be separated very easily by the separation claw 9 and supplied to the conveyor belt 4.

The static eliminator according to the present invention has been described above with respect to a device in which a transfer material is attached to a drum-shaped or other transfer material support member and the transfer material is passed through the transfer site multiple times. It is easy to understand that it can be applied to a device that is held on a shaped support material and performs a plurality of transfers while moving in a straight line.

Since the present invention has the configuration as described above,
When performing multiple transfer operations such as in a color image forming apparatus, the potential of the toner image surface is adjusted by the static eliminating electrode for each transfer, so there is no need to increase the transfer potential in the subsequent transfer process. Since the above-mentioned drawbacks due to the presence of a high potential can be eliminated, images without color shift can be obtained electrokinetically. Furthermore, since the attraction force between the transfer material and the dielectric mesh screen is released after the transfer is completed, the transfer material can be easily and reliably separated.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a color copying machine equipped with a static eliminator according to the present invention, and FIG. 2 is a side view of essential parts showing the configuration of the static eliminator according to the present invention. 1...Photoreceptor, 2Y, 2M, 2C...Developer, 3...Transfer material support drum, 5...Cassette, 7, 9- Constant stagnation, (3a, 8bs-Static charge removal electrode-10-

Claims (1)

[Scope of Claims] In an image forming apparatus in which a transfer material supporting member holding a transfer material is run and the transfer material passes through a transfer site multiple times, the transfer material supporting member is located downstream of the transfer site. 1 on both sides of the skinned member so that the transfer material passes through each transfer.
A pair of opposing static eliminators is arranged, and each time the transfer material passes, the static eliminator on the same side as the transfer material passes, and the static eliminator on the opposite side is removed. At least at the time of final transfer, the static electricity removal device performs FI.