JPS59150760A - Method and apparatus for preparing electrostatic recording head - Google Patents

Abstract

PURPOSE:To make it possible to automate the formation of an insulating layer, by applying potential having polarity the same as that of a fine powder to the multi-needle electrode of an electrostatic recording head while applying potential having inverse polarity to a control electrode to charge and spray the fine powder prepared by solidifying insulating particles with a heat-meltable binder resin from a nozzle. CONSTITUTION:For example, voltage of +50kV is applied to a nozzle 15 from a power source E3 and a fine powder prepared by solidifying insulating particles with a heat meltable binder resin is sent under pressure from a tank 18 by a pump 17 to inject the charged fine powder to an electrostatic recording head. On the other hand, for example, voltage of +500V is applied to the multi-needle electrode of the electrostatic recording head from a power source E2 while voltage of -500V is applied to a control electrode 12 from a power source E1. Therefore, the charged and injected fine powder is repelled from the multi-needle electrode 10 and attracted and selectively adhered to the control electrode 12 and, thereafter, melted under heating to be integrated therewith. By this method, the local formation of an insulating layer to the electrostatic recording head can be automated and the mass production thereof can be easily performed.

Description

Detailed Description of the Invention (Field of Application) The present invention relates to a method and apparatus for manufacturing an electrostatic recording head used in printers, facsimile machines, etc.
The present invention relates to a method and apparatus for manufacturing an electrostatic recording head that can easily maintain a predetermined constant gap between a multi-needle electrode and a dielectric recording medium in a surface control type transfer electrostatic recording head.

(Prior Art) FIG. 1 is a longitudinal sectional view of a commonly used multi-needle electrode type electrostatic recording head, and FIG. 2 is a sectional view taken along the line A--A. The multi-needle electrodes 1o are arranged in multiple rows and embedded in the epoxy mold 11.

On both sides of the multi-needle electrode 10, control electrodes 12 are arranged in pairs so as to face a group of multiple multi-needle electrodes 10.

As is well known, especially in transfer-type electrostatic recording devices, it is necessary to generate discharge at the tip of a multi-needle electrode in order to form an electrostatic latent image. It is necessary to provide a microgap between the needle electrode and the dielectric recording medium (not shown).

Conventionally, this method involves smoothing the surface of the dielectric recording medium, and as shown in FIGS. A method is known in which the exposed portion is covered with an insulating layer 13 and the thickness of the insulating layer 13 is used to ensure an appropriate air gap.

In this case, as a specific method for forming the insulating layer 13, for example, the tip exposed portion of the multi-needle electrode 10 is
After covering with an extremely narrow masking tape of ~0.5 mnnjLJ, it is necessary to form the insulating layer 13 by a spray method or the like.

Therefore, in this case, the creation of masking tape,
The result of the multi-needle electrode 10 of Day 7 was that it required a lot of work and skill, and was not suitable for automation or mass production of the manufacturing process of electrostatic recording heads.

(Purpose) The present invention has been made to improve the above-mentioned drawbacks, and its purpose is to automate the local formation of an insulating layer on the electrostatic recording surface and facilitate mass production. It is an object of the present invention to provide a method J3 and an apparatus for manufacturing an electrostatic recording head, which can be used to produce an electrostatic recording head.

(Summary) In order to achieve the above-mentioned object, the present invention has J5 (- means
A fine powder made of insulating particles hardened with a heat-melting binder resin is injected from a nozzle to which high pressure is applied, and the fine powder is charged.On the other hand, on the electrostatic recording head side, a multi-needle electrode is charged with the fine powder. A potential of the same polarity is applied, and a potential of opposite polarity to that of the fine powder is applied to the control electrode.

In addition, as a specific means for this purpose, in addition to equipping each potential applying means, if necessary, a "grid" is arranged in front of the insulating layer forming surface of the electrostatic recording head, and the above-mentioned fine powder is placed on this grid. By applying potentials of the same polarity and further covering the grid with an insulating material, the durability and operation rate of the manufacturing process of the electrostatic recording spatula 1- are improved.

(Example) First, the present invention will be explained in detail with reference to the drawings. FIG. 3 is a schematic block diagram showing one embodiment of the present invention. In the figure, the same reference numerals as in FIGS. 1 and 2 refer to the same or equivalent parts.

The nozzle 15 is connected to a power source E3 (for example, a positive 50
KV) is applied. In the tank 18, there is a fine powder made of insulating particles hardened with a heat-melting binder resin (for example, ethylene tetrafluoride hardened with a polynisdel resin binder).
is stored.

The fine powder is ejected from the nozzle 15 toward the front surface of the electrostatic recording head by the pump 17, and at this time, as is well known, the fine powder is charged to the same polarity as the power source E3.

On the other hand, the multi-needle electrode 10 of the electrostatic recording head is supplied with a voltage of the same polarity as the power supply E3 (for example, +500V) by the power supply E2.
V) is applied to the control electrode 12 by the power source E1, and a voltage of opposite polarity to the type 11nE3 (for example, -) is applied to the control electrode 12 by the power source E1.
500V) is applied.

Therefore, the fine powder is repelled from the multi-needle electrode 10 and attracted from the control electrode 12, and selectively adheres only to the control electrode 12.

Excess fine powder that has not adhered is collected by one tray and returned to the tank 18.

In experiments conducted by the inventor, E1=-500V.

E2=+500V.

E 3 = + 50 K V.

Opening diameter of nozzle 15 = 0, 5 nun.

Distance between nozzle 15 and head recording surface - 300 mm.

Multi-rainbow electrode 10 = 12 N'i wires with a diameter of 50 μm 7
Control type 8!12 = made of phosphor bronze, fine powder particles 16 = fine powder made of 4-ethylene fluoride hardened with a polyester resin binder. Then, while moving the nozzle 15 and the head at a relative speed of 15 mm/sec, the fine powder was deposited on the control electrode 12 by electrostatic spraying.

After that, the adhered fine powder binder was heated and melted using a flash lamp to be integrated, and then dried and hardened at room temperature.

Through the above steps, the surface of the control electrode 12 has (8±1)
An insulating layer 13 consisting of a coating film with a thickness of μm was formed, and no coating film was attached to the surface of the multi-needle electrode 10.

In this case, the higher the absolute value of the voltage applied to the square boxy mold 11 and the control electrode 12, the better, but the value (500 V) of the above-mentioned experimental example was the limit of the withstand voltage of both.

Further, the thickness of the insulating layer 13 can be appropriately controlled by changing the adhesion time of the fine powder, but it is preferably set to a thickness of 2 to 15 μm.

Furthermore, it is desirable that the insulating layer 13 contains a fluorine-based material,
In this case, the Mazza coefficient becomes small, the amount of toner (J'i'=) on the tip surface of the multi-needle electrode 10 decreases, and it is possible to guarantee good image quality for a long period of time.

As described above, in this embodiment, the fine powder is selectively attached to the surface of the control electrode 12, and the control I electrode 1
The insulating layer 13 can be formed only on the surface of 2.

However, if the particle size of the fine powder itself has large variations, and/or the amount of charge is small, or if the jet speed of the fine powder particles 16 is not uniform, the thickness of the insulating layer 13 may become uneven. Inconveniences such as fine powder adhering to the multi-needle electrode 10 may occur.

A second embodiment of the present invention improves the inconvenience of (e) above, and the schematic configuration of the device is shown in FIG.

In this figure, the same reference numerals as in FIG. 3 represent the same or equivalent parts.

As is clear from the comparison in FIG.
'j; In absolute terms, grid wires 20 are arranged on the recording surface side of the electrostatic recording head, and on this grid wire 20,
An intermediate potential (for example, +300 V) between the potential of the multilayer electrode 10 and the potential of the control electrode 12 is supplied by the power source F5.

By arranging the grid wires 20 in this way and applying a potential thereto, the multi-needle electrode 10 and the control electrode 1
2, an electrostatic lens is formed in front of each.

Therefore, the charged fine powder particles 16 are transferred to the control electrode 12
At the front surface of the multi-sensor electrode 10, the light is focused by the accelerating electric field formed there, and at the front surface of the multi-sensor electrode 10, the light is repelled by a repulsive force due to the decelerating electric field formed there.

Therefore, adhesion of the fine powder particles 16 to the multi-needle electrode 1o is reliably prevented, and selective adhesion on the surface of the control electrode 12 is ensured.

As described above, according to the second embodiment, the fine powder can be selectively deposited only on the control electrode 12 even if the fine powder itself is uneven in terms of particle size, chargeability, and acceleration. Can be done. The subsequent processing is the same as in the first embodiment.

In the inventor's experiment, a tungsten wire with a diameter of 200 μm was used as the grid wire 20.
Head 1) 2m from the 0th surface
The grid wires 20 are arranged at the position m, and the power source E
5 to +300V was applied.

Other conditions were the same as in the first example. As a result, the surface of the control electrode 12 is coated with 8±1) μ
A coating film with a thickness of m was formed, and no coating film was formed on the multi-needle electrode 16.

A3, if the grid voltage is too high, the fine powder will fall on the control electrode 1.
If the temperature is too low, the adhesion to the control electrode 12 tends to decrease. Also, it is better to bring the grid wire 20 closer to the head because it has more needles and 4 wires! Although it has the effect of preventing adhesion to the control electrode 12, if it is too thick, the thickness of the coating film on the control electrode 12 will become uneven.

Therefore, the voltage applied to the crit wire 20 and the distance between the head and the glyph wire 20 need to be experimentally selected to the optimum position.

However, in the second embodiment, even when various dimensions, voltages, etc. are set optimally, if the work of forming an insulating layer on the surface of the control electrode 12 is continued for a long time, grit wire A7
As fine powder adheres to the control electrode 12, the thickness of the insulating layer formed on the control electrode 12 may become uneven, or the insulating layer may become too thick.
It may also become attached to the surface of the electrode. The third embodiment c' of the present invention eliminates this tendency.
be.

In the third embodiment, although not shown, as the grid wire 20 shown in FIG. 4, an insulated hair 1, which is a fine metal wire coated with an insulating material, is used.

This prevents fine powder from adhering to the grid wire 20, and even if it does, there is little deterioration in selective adhesion performance of the fine powder to the control electrode 12, and the fine powder is prevented from adhering to the multi-side electrode 10. It has been experimentally confirmed that body adhesion is prevented.

The apparatus used in the experiment by the present inventor is the same as that shown in FIG. 4, and the grid wire 20 is 200 μm thick.
A thin wire made of a tungsten wire with a diameter of 5 μm and a glass coating of 1. m... Those arranged at a pitch were used. , the other conditions are exactly the same as in the second embodiment.

Therefore, according to the third embodiment, in addition to the effects obtained by the first and second embodiments, the selective removal of the insulating layer 13 to the control electrode 12, the maintenance and replacement of the grid wire 2° Since it can be carried out for a long period of time without needing to operate, it has the special effect of increasing work efficiency and improving the efficiency of using the equipment.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a multi-needle electrode type electrostatic recording device commonly used in the past, FIG. 2 is a Vji plane view taken along line A-A, and FIG. FIG. 4 is a schematic block diagram of a second embodiment of the present invention. 10...Multi-needle electrode, 11...Cohoxy mold,
12... Control electrode, 13... Insulating layer, 15... Nozzle, 16... Fine powder particles, 17... Pump, 18
...Tank, 20...Gridwire agent Michito Hiraki and 1 other person

Claims (5)

[Claims] (1) - Multi-needle electrodes arranged in a row and embedded in an insulating substrate, one end of which is exposed; and both sides of the row of multi-needle electrodes in the same plane as the exposed surface of the multi-needle electrodes. - and with these plurality of electrodes as one group, a plurality of sets of control electrodes arranged oppositely in pairs sandwiching the plurality of control electrodes, and an insulating layer formed on at least the exposed surface of the control electrodes. In a method for manufacturing an electrostatic recording head, fine powder particles made of insulating particles hardened with a heat-melting binder are charged by being injected from a nozzle to which high pressure of negative polarity is applied, and all of the multi-needle electrodes of the electrostatic recording head are charged. A voltage with the same polarity as the nozzle voltage is applied to the control electrode, and a lightning J1 with the opposite polarity to the nozzle voltage is applied to all of the control electrodes. 1. A method for manufacturing an electrostatic recording head, characterized in that fine powder particles are attached to the surface of the material, then heated and melted to integrate, and then dried and assimilated to form an insulating layer. (2) The method for manufacturing an electrostatic recording head according to claim 1, wherein the insulating layer contains a fluorine-based material. (3) - Multi-needle electrodes arranged in a row and embedded in an insulating substrate, one end of which is exposed; and a plurality of sets of control electrodes arranged opposite to each other in pairs sandwiching the plurality of control electrodes as one group, and an insulating layer formed at least on the exposed surface of the control electrode. In a head manufacturing device, nozzles are arranged opposite to each other in front of an electrostatic recording head on which multi-needle electrodes and control electrodes are formed, and fine powder particles made of insulating particles hardened with a heat-melting binder are fed under pressure to the nozzles. , a pump for scattering the fine powder particles toward the □ front surface of the electrostatic recording head; a means for applying a unipolar high voltage to the nozzle to charge the scattered fine powder particles to the negative polarity; An apparatus for manufacturing an electrostatic recording head, comprising means for applying a voltage of the negative polarity to the needle electrode, and means for applying a voltage of the other polarity to the control electrode. (4) - multi-needle electrodes arranged in a row and embedded in an insulating substrate, one end of which is exposed; and both sides of the row of multi-needle electrodes in the same plane as the exposed surface of the multi-needle electrodes and a plurality of sets of control electrodes arranged opposite to each other in pairs sandwiching the plurality of control electrodes as one group, and an insulating layer formed at least on the exposed surface of the control electrode. In a recording head manufacturing device, fine powder particles made of insulating particles hardened with a heat-melting binder are fed under pressure to a nozzle, such as a nozzle placed opposite to the front surface of an electrostatic recording head on which a multi-needle electrode and a control electrode are formed. a pump for scattering the fine powder particles toward the front surface of the electrostatic recording head; a means for applying a unipolar high voltage to the nozzle to charge the scattered fine powder particles to the -polarity; means for applying a voltage of the negative polarity to the needle electrode; means for applying a voltage of the other polarity to the control electrode; An electrostatic recording head comprising: a grid wire; and means for applying a voltage intermediate between the voltage applied to the multi-needle electrode and the voltage applied to the control electrode to the grid wire. Manufacturing equipment. (5) The electrostatic recording device according to claim 4, wherein the grid wire A7 is made of a thin metal wire coated with an insulating layer.