JPS599907B2 - electrostatic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic recording device in which the surface of an electrostatic recording member is an insulating layer, and an electrostatic image is created by selectively applying a charge to the surface of the insulating layer.

As conventional electrostatic recording devices, devices that form an electrostatic image by sliding a recording electrode onto the surface of an insulating electrostatic recording member to apply an electric signal are widely used.

Other devices that form an electrostatic image by scanning an electron beam on the surface of an insulating electrostatic recording member have also been put into practical use in some places in recent years. Among the electrostatic recording devices described above, those using the former recording electrode must always maintain a constant degree of contact between the electrode and the electrostatic recording member, and therefore require a special mechanism. Furthermore, dielectric breakdown between the electrodes occurs due to deformation of the recording electrodes and adhesion of contaminants such as dust. Therefore, a protection mechanism is required to prevent electrode wear and contaminant adhesion. As described above, those using recording electrodes have many limitations in the mechanism of the apparatus, and have drawbacks such as the difficulty of transferring a visual image on the surface of an electrostatic recording member and then using the recording member again. The latter method that uses an electron beam requires means for creating a vacuum between the electrostatic recording member and the electron beam. Therefore, there are drawbacks such as the device becoming large-scale. An object of the present invention is to eliminate the various drawbacks of the conventional electrostatic recording apparatus as described above, and to provide an electrostatic recording apparatus that is inexpensive and has stable performance.

The apparatus for forming an electrostatic image on an electrostatic recording member according to the present invention first uniformly pre-charges the surface of the insulating layer of the recording member. Next, selective charging or neutralization is performed using a corona discharger that further increases or lowers the surface potential of the insulating layer due to the charging. Note that this charging or discharging is performed via electrodes that control the passage of charges from the discharger according to a signal pattern. Therefore, a potential difference is generated in a portion of the charge on the surface of the insulating layer that has been uniformly charged by the pre-charging, and an electrostatic image is created due to the potential difference. The electrode for controlling the passage of charge has a slit-shaped opening along the corona discharger, and the opening has a group of electrodes facing each other and being shifted by an H pitch.

Next, the present invention will be described in further detail below using examples and drawings as necessary.

The electrostatic image forming process exemplified below is based on a method of obtaining an electrostatic image by removing charges on the surface of the insulating layer due to pre-charging. The diagrams shown in FIGS. 1A to 1D illustrate the process of forming an electrostatic image on an electrostatic recording member and the state of charge on the surface of the member.

Here, a is the pre-charging process, b is the recording process, c is the developing process,
And d shows the process of transferring a visible image by development. Below a
The process from to d will be described in more detail. a in Figure 1
In the pre-charging process shown in , the surface of the insulating layer 2 of the electrostatic recording member C having the conductive support 1 and the insulating layer 2 is uniformly charged, for example, positively (G) by a corona discharger 3 .

In the recording process shown in the following b, the charge on the insulating layer 2 formed by the pre-charging is selectively removed by the negative (c) polarity charge 13 from the AC corona discharger 4, thereby creating an electrostatic image. obtain. That is, a control electrode 5, which will be described later, passes the charge 13 according to a signal pattern, eliminates the charge on the surface of the insulating layer 2, thereby creating a potential difference on the surface, and an electrostatic image is obtained by this potential difference. The above-mentioned electrostatic image is reversely developed and visualized by charged colored particles 6 having the same polarity as the primary charge in the developing process shown in the following c. In the subsequent transfer process, as shown in d, the developed image of the colored particles 6 is
A transfer material 7 such as paper is placed on top of the transfer material 7, and an external voltage 8 such as a corona discharge or a bias potential is applied from the back side to perform the transfer. Regarding the control electrode 5, FIG. 2a is an explanatory diagram showing the configuration of the control electrode 5, and B and c are explanatory diagrams showing the passage and blocking of charges by the control electrode 5. .

In the figure, the control electrode 5 has electrodes A and B formed on both sides of an insulating plate 9, and a passage hole 12 through which the charge 13 passes is provided in a direction perpendicular to the insulating plate 9. If the charge 13 has a negative (C) polarity, when a negative (C) voltage is applied to the electrode A and a positive (A) voltage is applied to the electrode B as shown in b, the charge in the passage hole 12 is An electric field is generated in the direction of accelerating 13. Conversely, as shown in c, when a positive (-F) voltage is applied to electrode A and a negative (c) voltage is applied to electrode B, the passage hole 1
2 creates an electric field that blocks the charge 13. As a result, the negative (C) charges are accelerated and pass through the passage hole 12 in the state b, but are blocked from passing in the state c. As described above, the control electrode controls the arrival of the charge that neutralizes the charged portion of the insulating layer. Note that the arrows in c are lines of electric force indicating the state of the electric field. Further, the voltage applied to the electrodes A and B can take various values depending on the mutual relationship with the static eliminating corona discharger, the control electrode, and the electrostatic recording member. The control electrode actually used in the electrostatic recording device according to the present invention has one or more control electrodes based on the above principle.
FIG. 3 shows a control electrode 14 that is a combination of control electrodes having a single passage hole as described above.

The electrode 14 controls the passage of charges for static elimination through the six passage holes 12 by one electrode Al, A2 of the insulating layer 9 and the other electrode Bl, B, , β3. It is something. FIG. 4 shows the electrode 14 in FIG.
The cross section when cut along the plane is shown. The control electrode 15 shown in FIG.
is made into a slit shape. The electrode 15 is connected to one electrode Al, A2 of the insulating layer 9, and the other electrode Bl,
B2 and B3 are used to control the passage of charges for static elimination through the slit portion. Note that FIG. 6 shows a cross section of the control electrode 15 in FIG. 5 taken along the - plane. Next, an example of a process for forming an electrostatic image on an electrostatic recording member according to the present invention will be described below.

An electrostatic recording member on which an electrostatic image is formed can be obtained by forming an insulating material on a support made of a conductive material.

This insulating material may be a polyester film with a thickness of 10 to 200 microns, but a polyester film with a thickness of 25 to 50 microns is particularly suitable. Furthermore, a seamless electrostatic recording member can be obtained by forming a thin film of polyurethane-polyester copolymer, which is an insulating material, on an endless conductive support by monomer coating and ultraviolet polymerization. Further, the charge polarity of the pre-charging performed on the electrostatic recording member may be either positive or negative, and the applied voltage may be selected according to the thickness of the insulating layer to a level that does not destroy the insulating layer. In the next recording process, the charge on the electrostatic recording member due to the pre-charging is selectively removed from the charge from the corona discharger via the control electrode. This charge removal may be performed using a direct current corona having a polarity opposite to that of the pre-charging, but if an alternating current corona is used, the insulator constituting the control electrode will not be charged. That is, as a result, when the discharge charge passes through the control electrode when necessary, it is not blocked by the electric field caused by the charge, so that a continuous electrostatic image can be obtained. For the above reasons, when an AC corona is used for static elimination, it is effective to increase the AC frequency in accordance with the moving speed of the electrostatic recording member. For example, the moving speed of the electrostatic recording member is 1001
A good electrostatic image can be obtained by using an alternating current corona discharge of 400 to 800 Hz at 1/sec or a pulsed voltage corresponding thereto. In this example, the electrostatic recording member which undergoes the pre-charging process is prepared by adhering a 25 micron thick polyester film to an aluminum alloy conductive support using an epoxy adhesive.

The pre-charging is + on the surface of the insulating layer on the surface of the electrostatic recording member.
A 7.0 KV corona discharge was applied. Due to this corona discharge, the surface of the insulating layer obtained a surface potential of +2000V. Next, we will discuss the arrangement position of the AC corona discharger and the control electrode for removing charges caused by pre-charging during the recording process. The control electrode was placed at a position of 1.5WIL from the surface of the insulating layer, and the AC corona discharger was placed at a position of 10ml from this electrode. Incidentally, corona discharge by the AC corona discharger was performed at 6KV and 1400 Hz. Next, regarding the control electrode, first, a 35 micron copper layer was provided on both sides of a 150 micron thick polyester base, and the copper layer on one side was photoetched to form a group of four electrodes/dragon. The material of the control electrode formed as above is
The electrode group was cut into two pieces using a sharp cutter in a direction perpendicular to the longitudinal direction of the electrode group. Then, as shown in FIG.
．． 3111! The electrodes were placed opposite each other and took the form of staggered electrodes.
By configuring as described above, the pitch does not shift due to production errors, and it is possible to form control electrodes with a pitch shift of %. Note that FIG. 8 shows a cross section of the control electrode 16 in FIG. 7 taken along the - plane. Further, the electrode group B was arranged to face the insulating layer side of the electrostatic recording member, and the copper plate electrode A on the opposite side was arranged to face the AC corona discharger side. The copper plate electrode A of the control electrode 16 arranged as described above was set to O, and a voltage of ±500 V was applied to the electrode group B according to the signal pattern. Then, when +500 is applied, the negative charge from the AC corona discharger is accelerated, reaches the insulating layer, and eliminates the positive charge on the insulating layer. Further, when -500V is applied, the negative (C) charges are blocked from passing and the positive (E) charges are not eliminated. That is, an electrostatic image due to the potential difference could be obtained on the surface of the insulating layer as described above. As shown in Figure 7 above, by shifting the electrode groups by a percentage pitch to form staggered electrodes, the charge emitted from the corona discharge electrodes is controlled continuously in the longitudinal direction by each electrode group, resulting in images with high resolution. It becomes possible to form.

FIG. 9 shows one embodiment of an electrostatic recording device embodying the electrostatic recording method according to the present invention.

In the figure, C indicates an electrostatic recording member having an insulating layer 2 around a grounded conductive support 1, which rotates in the direction of the arrow.
The electrostatic recording member C is first uniformly pre-charged by the pre-charging corona discharger 3. Next, by controlling the arrival of charge for static elimination from the AC corona discharger 4 using the control electrode 17, an electrostatic image is formed on the surface of the insulating layer. Here, 10 is a device that generates a signal pattern to be sent to the control electrode 17. The electrostatic image is developed in a developing device 18 using a developer 23 containing a carrier liquid and charged colored particles. In addition to liquid development, dry development is also possible. During this development, excess developer on the electrostatic recording member C is squeezed out by the aperture charger 19 without disturbing the developed image. The visible image on the recording member C moves in contact with a transfer material 7 such as paper that is fed by a conveyance roller 20, and is transferred by applying a corona discharge from the back side of the recording member C with a corona discharge having a polarity opposite to that of the charged colored particles by a corona discharger 8. After the transfer, the transfer material 7 is peeled off from the electrostatic recording member C by a peeling means such as a peeling pawl 21, and then fixed by a fixing device 11. On the other hand, the insulating layer 2 is cleaned by a cleaning means such as a cleaning blade 22 in preparation for the next electrostatic recording process. As described above, the present invention is an apparatus for recording an electrostatic image on an electrostatic recording member without using a recording electrode that is brought into close contact with or in close contact with the recording member or an electron beam that requires a vacuum device.

According to the present invention, there is no need for the recording means to be brought into close contact with the electrostatic recording member unlike when recording electrodes are used. Therefore, no dust or the like is accumulated between the electrostatic recording member and the special mechanism or recording means for keeping the density uniform. Furthermore, since there is no need for a vacuum device unlike when using an electron beam, it has become possible to downsize the device. Furthermore, since the recording member and the recording means are not in close contact with each other, dielectric breakdown due to wear or dust on the recording means does not occur. That is, the present invention has made it possible to eliminate the various drawbacks of the conventional electrostatic recording apparatus as described above, and to provide an electrostatic recording apparatus that is inexpensive and has stable performance. Further, by shifting the control electrodes by a percentage pitch to form staggered electrodes, continuous control is possible with the control width of the electrodes.

Furthermore, by cutting the material and constructing the electrodes by shifting the pitch by a percentage, it is possible to easily construct control electrodes in which each electrode is completely shifted by a pitch by a percentage.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 is a diagram explaining the principle of the control electrode according to the present invention, FIG. 3 is a plan view of the control electrode, and FIG.
The figure is a cross-sectional view taken along line I-1 of the electrode shown in Figure 3, Figure 5 is a plan view of the control electrode, Figure 6 is a cross-sectional view taken along the - line of the electrode shown in Figure 5, Figure 7 is a plan view of the control electrode, and Figure 8 is a plan view of the electrode shown in Figure 5. FIG. 7 shows a sectional view taken along the line 7 of the electrode, and FIG. 9 shows a side view of an electrostatic recording device embodying the present invention.

Claims (1)

[Claims] 1. In an electrostatic recording device that controls the passage of corona ions from a corona ion generation source using a control electrode having a slit opening, and selectively applies corona ions onto an electrostatic recording member to form an electrostatic image. The control electrode has an electrode on the corona ion generation source side and an electrode on the electrostatic recording member side with an insulating layer interposed therebetween, and the electrode on the electrostatic recording member side located through the insulating layer has the slit opening An electrostatic recording device characterized in that it has a group of electrically independent electrodes that are equally spaced along the slit, and the electrode groups are arranged with a 1/2 pitch offset from each other through a slit opening. .