JPS5844472A - Toner transfer method of recording system - Google Patents

Abstract

PURPOSE:To obtain excellent recorded images free of ground staining by placing the circumferential surface of an intermediate transfer medium with an insulating layer close to a donor at an extremely small interval, applying a DC deviated AC voltage and scattering toner, and passing the toner onto the circumferential surface of the intermediate transfer medium and thus performing transfer to a transfer member. CONSTITUTION:An intermediate transfer medium 6 includes a metallic roller 6A with an insulating layer 6B and is provided under a donor 1 at an interval (g). A transfer member 6 includes a metallic roller 6A having an insulating layer 7b around its circumferential surface, and conveys recording paper S by pressing it against the intermediate transfer medium 6. The metallic roller 7A is applied with a DC transfer voltage of, e.g. -450V from a power source 7D. Consequently, the leaking of charge through the recording paper S is prevented during the transfer of a toner image to the recording paper S because of the presence of the electric insulating layer 7B to prevent the disorder of the transferred image caused by the leaking.

Description

[Detailed description of the invention] The present invention relates to a toner transfer method in a recording system.

A multi-needle electrode to which a pattern signal is applied is brought into contact with a highly electrically resistive toner having charge-retaining properties, and a charge distribution of the toner according to the pattern signal is obtained on the donor by utilizing charge injection into the toner, A recording method has been proposed in which this charge distribution is used to form a visible pattern (Japanese Patent Laid-Open No. 55-84
No. 955).

One of the devices for concretely implementing such a recording method
As an example, the one shown in Figure 1 for 1 year has been proposed. First, an outline of the above-mentioned recording system will be explained with reference to FIG. 1, and a problem to be solved by the present invention will also be described.

In Figure 1, code 1 is the donor, code 2 is the hopper,
Reference numeral 3 indicates a doctor, reference numeral 4 a multi-needle electrode, and reference numeral 5 a transfer member.

The donor 1 is formed into a roller shape and is rotatable in the direction of the arrow. The hopper 2 has an opening for toner replenishment, and is disposed above the donor 1 so that the opening is covered by the upper surface of the donor 1. Hopper 2
stores toner T, and this toner T is replenished onto the upper peripheral surface of the donor 1 from the opening of the hopper 2, and moves together with the surface of the donor 1 when the donor 1 rotates in the direction of the arrow. Regarding the movement of donor 10, hopper 2
The side that welcomes the above situation is called the entrance side, and the side that sends out the above situation is called the exit side.

The doctor 3 is installed on the inner wall of the hopper 2 on the exit side, and its edge is suppressed by the suppressing means 34.

It is brought into pressure contact with the surface of the donor 1 in the direction of the rotation axis of the donor. The direction of the rotation axis of the donor is, of course, the direction perpendicular to one drawing.

When the donor 1 rotates in the direction of the arrow, the toner T supplied to the donor surface moves together with the donor 1, but the movement is regulated by the doctor 3, so the action of the doctor 30 causes the toner T to be transferred to the donor 10 surface. A uniform thin layer is formed. The doctor 3 is electrically conductive and is connected to a power source (not shown). When forming a uniform thin layer of toner T on the donor 1, the doctor 3 injects negative charge into the toner T and makes it have a negative polarity. to be charged.

Therefore, the thin layer of toner T formed on the donor 1 by the doctor 3 is uniformly negatively charged.

The multi-needle electrode 4 has a plate shape that is elongated in the direction perpendicular to the drawing, and has one end along its longitudinal direction.

The minute end faces of a large number of buried needle electrodes are exposed in an orderly arrangement. The multi-needle electrode 4 connects the exposed end edge of the needle electrode to the surface of the donor 1 through a uniform thin layer of toner T.

They are pressed together in the longitudinal direction.

When a pattern signal is applied to the multi-needle electrode 4, positive charges are injected from the needle electrode according to the pattern signal. Since the toner injected with positive charges is positively charged, a distribution of positively charged toner and negatively charged toner, that is, a toner charge distribution is obtained on the donor 1. Among these, the distribution of positively charged toner follows the pattern signal and corresponds to the pattern image to be recorded.

The transfer member 5 is a metal roller, and its rotation axis is parallel to the rotation axis of the donor 10, and the rotation axis is applied from below the donor 1 to the peripheral surface of the donor 1 They are brought into contact in all directions.

The recording paper S is conveyed in the direction of the arrow and passes through the transfer section, that is, the contact section between the donor 1 and the transfer member 5.

A voltage of negative polarity is applied to the transfer member 5 from the power supply 5A as an insulating pressure for transfer, and due to the action of this insulating pressure, positively charged toner is transferred.

The toner is transferred onto recording paper S as a recording medium according to the charge distribution.

The transferred toner image corresponds to the pattern image,
The image is fixed onto the recording paper S by a fixing device (not shown). The above is an overview of the recording method.

In such a recording system, problems that must be solved arise in connection with the transfer member 5.

That is, since the donor 1 and the transfer member 5 are in pressure contact with each other through the recording paper S during recording, toner adhesion to the recording paper occurs even when there is no charge due to the pattern signal.
So-called background stains are likely to occur in recorded images.

An object of the present invention is to provide a toner transfer method that can effectively solve such a time delay.

The present invention will be explained below.

The features of the present invention are as follows.

The toner to be transferred on the donor is first transferred from the donor onto an intermediate transfer medium according to its charge distribution, and then transferred from the intermediate transfer medium onto a recording medium such as recording paper by a transfer member.

The intermediate transfer medium is constructed by providing an electrically insulating layer on the circumferential surface of a conductive belt or a conductive roller, and the transfer member is constructed in the shape of a belt or a roller.

The intermediate transfer medium has its surface closely opposed, with a small gap, to the toner on the donor. The above minute gap is 20
Approximately 300 μm is suitable.

An alternating current voltage biased to direct current is applied as a transfer voltage to the intermediate transfer medium. Of course, the DC component has a polarity opposite to that of the toner to be transferred. The toner to be transferred flies through the minute gap and is transferred onto the circumferential surface of the intermediate transfer medium by the action of the transfer voltage. In order to transfer the toner by flying it through a minute gap, it is extremely effective to use a transfer voltage biased to direct current.

This became clear through experiments conducted by the present inventors.

In this way, the toner image obtained on the intermediate transfer medium is transferred onto the recording medium by the action of the transfer member. Of course, a transfer voltage having a polarity opposite to that of the toner image is applied to the transfer member.

If the recording medium is recording paper and the toner image is transferred to its surface, the toner image obtained on the intermediate transfer medium must be a mirror image of the recorded image...□.

Therefore, the toner must be on the donor.

It is necessary to form a charge distribution corresponding to the normal image of the recorded image. However, if a transparent sheet such as Mylar film is used as the recording medium and is placed on the intermediate transfer medium, the toner image on the intermediate transfer medium may be a normal image, and the charge distribution formed on the donor will be different.

As in the case shown in Figure 1, a recorded image can be made into a bronze statue.

As a method of applying a DC-biased transfer voltage to the intermediate transfer medium, an alternating current superimposed on a direct current may be directly applied to the conductive portion of the intermediate transfer medium.

In order to uniformly charge the circumferential surface of the intermediate transfer medium and apply an alternating voltage that should be superimposed on the direct current voltage due to the charged charges, the alternating current voltage may be directly applied to the conductive portion.

The absolute value of the DC component in this DC biased AC 1′ pressure is 100 to 100 OV, and the effective value of the AC component is 50 to 2
00v and a frequency of 20 to 1000 Hz are appropriate.

A specific example will be described below with reference to one drawing.

FIG. 2 schematically shows only the parts necessary for explanation of an example of a toner image transfer device to which the present invention is applied. In the figure, code 1 is
As in Figure 1, the donor is shown.

The intermediate transfer medium 6 designated by the reference numeral 6 is roller-shaped, and has an electrically insulating layer 6B on the curved surface of the metal roller 6A.
It is configured with the following. During the experiment, this electrical insulating layer had a mechanical strength of 1! It is made of Teflon, which has been heat-treated to increase its mechanical strength, taking into consideration its mechanical properties.

This intermediate transfer medium 6 is placed below the donor 1.

Its rotation axis was made parallel to the rotation axis of the donor 1, and the upper curved surface was closely opposed to the thin toner layer on the peripheral surface of the donor 1 with a minute gap g interposed therebetween in the direction of the rotation axis.

In order to maintain this minute gap g, spacers with a diameter slightly larger than the diameter of the intermediate transfer medium 6 are provided at both ends of the rotation axis of the intermediate transfer medium 60, and these spacers are connected to both ends of the rotation axis of the donor l. The intermediate transfer medium 6 and the peripheral surface of the donor 1 are brought into contact with the peripheral surface end of the donor 1, and the minute gap between the intermediate transfer medium 6 and the peripheral surface of the donor 1 is 10.
It was controlled to maintain 0 μm. Further, a DC power source 6D is connected to the metal roller 6A of the intermediate transfer medium 6.
The AC power source 6C was configured to apply a DC-biased transfer voltage. This transfer voltage is a DC component of -300V.
.

The AC component was 50 V and the frequency was 200 Hz. Further, a cleaning blade 8 is provided to clean the intermediate transfer medium after the toner image is transferred, and the toner removed by the cleaning blade 8 is collected by a collection member 9.

The transfer member 7 was constructed by covering the circumferential portion of a metal roller 78 with an electrically insulating layer 7B. This electrical insulating layer 7B
Teflon, whose mechanical strength has been strengthened through heat treatment, was used as the material.

The transfer member 7 is arranged so as to be able to pinch and convey the recording paper S as a recording medium together with the intermediate transfer medium 6, and the metal roller 7A IC receives a DC generous voltage from a power source 7D.
450v was applied. Electrical insulation layer 7B
Due to the presence of the toner image, it is possible to prevent charge from leaking through the recording paper S when the toner image is transferred to the recording paper S, and it is possible to prevent disturbance of the transferred image due to the leakage.

A single layer of negatively charged uniformly charged toner is formed on the donor 1, and positive charges are injected using a multi-needle electrode, and the charge distribution of the toner is adjusted so that the distribution of the positively charged toner corresponds to the positive image of the recorded image. Form the positively charged toner with the transfer device shown in Figure 2, according to the charge distribution.

When the image was transferred onto recording paper S and fixed, a good recorded image without background stains could be obtained.

In addition, donor 1. Intermediate transfer medium6. The peripheral speed of the transfer member 7 was 50 mm/8ee.

[Brief explanation of the drawing]

Figure A.1 is a diagram for explaining the recording method to which the present invention is applied, and Figure A.2 is a diagram for explaining the recording method to which the present invention is applied.
It is a front view showing an example.

Claims (1)

[Claims] A multi-needle electrode to which a pattern signal is applied is brought into contact with a highly electrically resistive toner having charge retention properties. By utilizing the charge injection into the toner, a charge distribution of the toner according to the pattern signal is obtained on the donor. In the recording method in which the charge distribution of the toner is used to form a visible pattern. A method of transferring toner on a donor onto a recording medium according to the charge distribution, the intermediate transfer medium having an electrically insulating layer provided on the circumferential surface of a conductive belt or a conductive roller is A DC-biased AC voltage is applied as a transfer voltage to the intermediate transfer medium, and the toner on the donor is caused to fly through the minute gap to the intermediate transfer medium. The toner image is transferred onto the circumferential surface of the intermediate transfer medium to obtain a toner image corresponding to the image to be recorded on the circumferential surface of the intermediate transfer medium. A toner transfer method characterized in that this toner image is transferred onto a recording medium by a transfer member formed in a roller or bell shape and to which a transfer voltage is applied.