JPH03109585A - Electrostatic latent image forming device - Google Patents

Abstract

PURPOSE:To obtain sufficient withstanding voltage and discharging durability by forming an insulating layer from a ceramic material. CONSTITUTION:The insulating layer 4 formed from the ceramic material is laminated on a substrate 2 where first electrodes 3a, 3b, and so on are formed, and second electrodes 5a, 5b and so on are formed over this insulating layer 4. Thus sufficient withstanding voltage and discharging durability are obtained, the cost is low and the handling is easy, the insulating layer 4 can be manufactured by a manufacturing method appropriate for mass production in forming process and firing process of the ceramic material, and a device of high reliability provided with strength to endure ion impact, stability to endure chemical reaction from activated matter and plasma generated from discharging, and heat durability against the rising of heater temperature can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for forming an electrostatic latent image used in electrostatic recording, and more particularly to an apparatus for forming an electrostatic latent image using ion flow control.

[Conventional technology]

Conventionally, as this type of electrostatic latent image forming apparatus, there are the following types. As shown in FIG. 5, drive electrodes 51, 51... are provided in parallel to each other on an insulating substrate 50, and the drive electrodes 51, 51... are intersected with an insulating layer 52 interposed therebetween. Control electrode 54.54
. . are provided, and a matrix is formed by drive electrodes 51, 51, . . . and control electrodes 54, 54, . In addition, two thin electrodes 55 are included in the control electrodes 54, 54...
．． 55 are arranged parallel to each other to form a spatial region 56 for ion generation between the picture electrodes 55 and 55. Furthermore, a flat screen electrode 58 is provided on the control electrodes 54, 54 through an insulating layer 57, and the screen electrode 58 has a spatial area of the control electrode 54, as shown in FIG. Circular openings 59, 59, . . . for ion extraction are provided only at positions corresponding to 56. In the figure, 60 is the insulating layer 5
The opening provided in 7 is shown.

As shown in FIG. 6, the electrostatic latent image forming device has drive electrodes 51, 51, control electrodes 54, 54, and so on.
A high frequency high voltage is applied between the control electrodes 54, 54, . . . and a DC voltage is applied to the screen electrode 58, respectively.

By doing so, a creeping corona discharge is generated in the spatial region 56 between the drive electrode 51 and the control electrode 54, and ions generated by this creeping corona discharge are accelerated or accelerated by the electric field between the control electrode 54 and the screen electrode 58. It absorbs ions, controls ion release, and forms an electrostatic latent image.

Incidentally, for the insulating layer 52, thinly peeled natural mica (mica) is used, and a thin plate of conductive electrode material such as copper or stainless steel is laminated on the surface of the natural mica, and each conductive thin plate is Drive electrodes 51, 51, . . . and control electrodes 54, 54, . . . are formed by photo-etching.

[Problem to be solved by the invention]

However, the above conventional technology has the following problems. That is, the electrostatic latent image forming device uses thinly peeled natural mica (mica) as the insulating layer 52, laminates a thin plate made of a conductive electrode material on the surface, and forms the drive electrode 51 by photo-etching. 51
... and control electrodes 54, 54... are formed.

Therefore, natural mica that can be used for insulating layers is
There is a problem in that it is limited to the highest quality, which has a predetermined size, has a constant thickness, and is uniform, which limits manpower and makes mass production difficult. Further, if there are scratches or defects in the insulating layer, there is a problem that creeping corona discharge does not occur or dielectric breakdown occurs, making it impossible to obtain stable discharge characteristics. Furthermore, since natural mica is used as the insulating layer, manufacturing the insulating layer requires skilled manual work such as peeling off the natural mica to a certain thickness and cutting it to a predetermined size. From this point of view as well, there was a problem in that mass production was difficult.

In addition, pressure-sensitive adhesives are used to laminate electrode materials on the surface of natural mica;
Due to the lack of heat resistance, discharge resistance, etc., the manufactured electrostatic latent image forming apparatus has a problem of poor stability and reliability.

[Means to solve the problem]

Therefore, this invention was made to solve the problems of the prior art described above, and its purpose is to provide a material that has sufficient voltage resistance and discharge resistance as an insulating material, and is also inexpensive and easily available. An object of the present invention is to provide an electrostatic latent image forming device that can utilize materials. Another object of the present invention is to provide a low-cost electrostatic latent image forming device that can be manufactured using a manufacturing method suitable for mass production. Furthermore, other objects of the present invention are to provide reliability such as strength that can withstand ion bombardment, stability that can withstand chemical reactions caused by active substances and plasma generated by discharge, and heat resistance against temperature rise of the heater. An object of the present invention is to provide an electrostatic latent image forming device with high performance. Another object of the present invention is to provide an electrostatic latent image forming device that can perform uniform discharge and that does not cause image unevenness in the formed electrostatic latent image. There is a particular thing.

Another object of the present invention is to provide an electrostatic latent image forming device that generates less ozone and discharge products and has a long life.

That is, the invention described in claim 1 of the present invention includes a plurality of first electrodes, a plurality of second electrodes, and an insulating layer, and the first electrode and the second electrode are The second electrode is provided in a matrix with the insulating layer in between, and the second electrode has a spatial region in which creeping corona discharge is caused by applying a voltage between the first electrode and the second electrode. In the electrostatic latent image forming device, the insulating layer is formed of a ceramic material.

Further, the invention described in claim 2 of the present invention provides a plurality of first electrodes, a plurality of second electrodes, a third electrode, and a first electrode.
an insulating layer and a second insulating layer, the first electrode and the second electrode are provided in a matrix with the first insulating layer in between, and the second electrode is The third electrode has a spatial region in which creeping corona discharge is caused by applying a voltage between the first electrode and the second electrode, and the third electrode
The third electrode is provided with the second insulating layer interposed between the electrostatic latent image and the second electrode, and the third electrode has an ion extraction region that extracts ions generated by the creeping corona discharge. The forming apparatus is configured to form the first and second insulating layers from a ceramic material.

Further, in the invention described in claim 3 of the present invention, the electrode and the insulating layer are integrally manufactured by sintering.

For example, alumina, zirconia, or the like is used as the ceramic material forming the insulating layer, and electrodes are formed using these ceramic materials in a so-called green sheet state before firing.

As the green sheet material, for example, alumina (A
l 20 +) powder with sintering aids (SiO,, Mgo,
CaO, etc.), and further added with organic binders, plasticizers, dispersants, etc. necessary for molding are used.

Further, as the first electrode and the second electrode, for example, tungsten (W) or molybdenum (Mo) is used.

A sintered metal conductor such as tungsten manganese (W-Mn) or molybdenum manganese (Mo.Mn) is used.

The electrostatic latent image forming device is manufactured by a method called a printing lamination method or a sheet lamination method.

Here, the printing lamination method refers to forming a first electrode by screen printing or the like on a relatively thick green sheet that serves as a substrate, and then forming an insulating layer on the substrate on which the first electrode is formed. After all, it is laminated by screen printing etc., and furthermore,
This refers to a manufacturing method in which a second electrode is formed on this insulating layer by screen printing or the like. Also, what is the sheet lamination method?
This is a manufacturing method in which electrodes are formed on a relatively thin green sheet as a substrate by screen printing or the like and dried, and then a plurality of sheets are laminated and pressed to form a multilayer.

In both the printing lamination method and the sheet lamination method, an electrostatic latent image forming device is finally obtained by firing the substrate formed as described above at a high temperature in a reducing atmosphere. At that time, the green sheets on which electrodes are formed and stacked will shrink by about 12 to 20% when fired, so the dimensions before firing will be the desired dimensions after firing, taking into account the shrinkage rate in advance. It is set as follows.

[Effect]

In the invention described in claim 1 of the present invention, since the insulating layer is formed of a ceramic material, the insulating layer has sufficient voltage resistance and discharge resistance, and is inexpensive and easily available. is good. In addition, since the insulating layer is made of a ceramic material, it can be manufactured using a manufacturing method suitable for mass production, such as a ceramic material molding process or a firing process, resulting in low-cost electrostatic latent image formation. equipment can be provided. Furthermore, since the insulating layer is made of ceramic material, it has the strength to withstand ion bombardment, the stability to withstand chemical reactions caused by active substances and plasma generated by discharge, and the heat resistance to heater temperature increases. A highly reliable electrostatic latent image forming device can be provided. Further, since the insulating layer is formed of a ceramic material, the insulating layer can be manufactured according to a predetermined shape and characteristics, and uniform discharge can be performed.

Further, since the insulating layer is formed of a ceramic material, sufficient dielectric strength can be obtained even if the insulating layer has a thickness of 10 to 50 μm. As a result, stable discharge can be obtained at a low voltage, so that it is possible to provide an electrostatic latent image forming device that generates less unnecessary ozone and discharge products and has a long life.

In addition, in the invention described in item 3 of this invention, both the insulating layer and the electrode are fired at high temperature and produced as an integrated sintered body, so not only is the insulating layer strong, but the electrode is also insulated. It has the same strength, stability, and heat resistance as the insulating layer, and also has an extremely strong bond between the insulating layer and the electrode.

[Example] The present invention will be explained below based on illustrated embodiments.

1 to 4 show an embodiment of an electrostatic latent image forming apparatus according to the present invention. In the figure, ■ is a recording head as an electrostatic latent image forming device, and this recording head 1
is equipped with an insulating substrate 2 made of a ceramic substrate such as alumina and having a rectangular planar shape. On the surface of this insulating substrate 2, a plurality of drive electrodes 3a, 3b, 3c... are provided in parallel with each other along the longitudinal direction, and the drive electrodes 3a
, 3b, 3c, . . . are bent toward both ends in the width direction of the insulating substrate 2. The drive electrodes 3a, 3b, 3c.
... are formed by pattern printing a metal such as tungsten on the insulating substrate 2 by screen printing or the like. The thickness of the drive electrodes 3a, 3b, 3c... is set to 5 to 40 μm, more preferably 10 to 20 μm.
It is set to μm. Further, drive electrodes 3a, 3b, 3c,
...The distance between them is set to 100 to 500 μm,
Preferably it is set to 200 to 400 μm. In the diagram, 3
a'3b'3c' ... are drive electrodes 3a, 3
3b, 3c, . . . show power feeding units provided at the ends.

An insulating layer 4 made of a green sheet, which is a ceramic sheet such as alumina, is laminated on the drive electrodes 3a, 3b, 3c, etc., and the thickness of the insulating layer 4 is 10 to 50 μm.
1 is preferably set to 20 to 30 μm. This insulating layer 4 has a width equal to that of the insulating substrate 2, as shown in FIG.
The length of the insulating layer 4 is shorter than that of the insulating substrate 2, and both longitudinal ends 4a and 4b of the insulating layer 4 are connected to the drive electrode 3.
Power supply parts 3a'3b' of a, 3b, 3c...
Drive electrodes 3a, 3b, 3c, leaving 3c'...
It is formed in a convex shape so as to cover the entire surface of...

On the insulating layer 4, drive electrodes 3a, 3b, 3C...
Control electrodes 5a, 5b, 5c, . . . are provided so as to intersect with each other at a predetermined angle to form a matrix. In this way, since the drive electrodes 3a, 3b, 3c... and the control electrodes 5a, 5b, 5c... are provided so as to constitute a matrix, the drive electrodes 3a, 3b...
, 3c-= and control electrodes 5a, 5b.

The discharge generation positions, which are the intersections with 5c..., are set so that they are arranged at a predetermined density, for example, 240 dat per inch, along the longitudinal direction of the recording head l.

These control electrodes 5a, 5b, 5c, . . . are formed by pattern printing a metal such as tungsten using a screen printing method or the like. Control electrodes 5a, 5b
, 5c... are the drive electrodes 3a, 3b, 3c...
・Similarly to 5 to 40 μm, more preferably 1
It is set to 0 to 20 μm.

The control electrodes 5a, 5b, 5c... are constructed by arranging two thin electrodes 6.6 parallel to each other and forming a spatial region 7 for ion generation between the picture electrodes 6.6. At the same time, one end portion 8 of the picture electrode 6.6 is connected to each other in a U-shape to form a planar substantially tuning fork shape. In addition, the control electrode 5
a, 5b, 5c, . . . are formed such that their U-shaped connection portions 8, 8, . In the figure, 5a'
5b' 5c... are drive electrodes 5a, 5b, 5c
. . . shows a power feeding section provided at the end of the...

As shown in FIG. 2, an insulating layer 9 made of green sheets made of ceramic sheets such as alumina is laminated on the control electrodes 5a, 5b, 5c, and so on. The insulating layer 9 is formed with a width and length shorter than that of the insulating substrate 2 by a screen printing method or the like.
In the control electrodes 5 a 15 b s 5 c . . ., spatial regions 7.7, .
7... Elongated oval shaped opening 10.10.
... is formed. The thickness of the insulating layer 9.9 is set to 10 to 50 μm, preferably 20 to 30 μm.
The thickness is set to μm.

Furthermore, as shown in FIG. 2, a screen electrode 11 as a third electrode is provided on the surface of the insulating layers 9,9, . . . with a spacer member 30 interposed therebetween. As shown in FIGS. 1 and 2, this screen electrode 11 includes drive electrodes 3a, 3b, 3c... and control electrodes 5a, 5b, 5
Circular openings 12, 12, . . . for ion extraction are provided only at positions corresponding to the intersections with c.

By the way, the recording head 1 configured as described above is manufactured as follows. That is, as the green sheet constituting the insulating substrate 2, for example, a green sheet made of 96% pure alumina and having a width of 4On+n+, a length of 200 mm, and a thickness of 1 mm is used. This green sheet consists of alumina (AA203) powder and a sintering aid (S).
iOx, MgO, CaO, etc.), and an organic binder, plasticizer, dispersant, etc. necessary for molding are also added.

The green sheet constituting the insulating substrate 2 is
A press method in which the green sheet material is press-formed using a press machine, a roll method in which the green sheet material is formed by passing it between a pair of rolls, a blade method in which the green sheet material is formed into a predetermined shape using a blade, etc. As described above, it is formed into a predetermined sheet shape.

Thereafter, a conductive paste made of tungsten or the like is printed in a predetermined shape by a screen printing method on the green sheet constituting the relatively thick insulating substrate 2 formed as described above. ,3C
... to form. These drive electrodes 3a, 3b, 3c...
* is formed to have a width of 200 μm and a thickness of 20 μm, for example.

Then, on the green sheet on which the drive electrodes 3a, 3b, 3C, etc. are formed, alumina paste, which is an insulator made of the same material as the green sheet constituting the insulating substrate 2 and whose viscosity is controlled, is applied by screen printing. By printing in a predetermined shape, the insulating layer 4 is laminated to a thickness of, for example, 30 μm.

Furthermore, control electrodes 5a, 5b, 5C, etc. are formed by printing a conductive paste made of tungsten or the like into a predetermined shape by screen printing on the alumina paste forming the insulating layer 4 formed as described above. Form. These control electrodes 5a, 5b, 5c... have, for example, an interval between the spatial regions 7.7... of 200 μm and a thickness of 20 μm.
The control electrodes 5a, 5b, 5c, .

Next, on the green sheet on which the control electrodes 5a, 5b, 5c, etc. are formed, alumina paste, which is an insulator made of the same material as the green sheet constituting the insulating substrate 2 and whose viscosity is controlled, is applied by screen printing. By printing in a predetermined shape, the insulating layer 9 can be formed to a thickness of, for example, 20 mm.
Form a layer in μm.

The multi-layered green sheets stacked in this manner are bonded by pressing with a predetermined pressure, and then fired at a temperature of 1500 to 1600°C in a reducing atmosphere furnace to form the insulating substrate 2 and the drive electrode. 3a, 3b, 3c
..., insulating layer 4, control electrodes 5a, 5b, 5c...,
An insulating layer 9 is integrally formed into a predetermined shape.

At that time, the green sheet forming the insulating substrate 2, etc.
By firing, it shrinks by about 20% from the above dimensions, and finally reaches the desired dimensions.

The alumina ceramic multilayer plate fired as described above has drive electrodes 3a, 3b, 3c, and 3c made of tungsten.
In order to prevent oxidation of the drive electrodes 3a, 3b, 3c... and the control electrodes 5a, 5b, 5c... and the control electrodes 5a, 5b, 5C..., nickel plating or the like is applied to the exposed parts of the drive electrodes 3a, 3b, 3c... and the control electrodes 5a, 5b, 5c... You can do it like this.

Finally, the recording head 1 is manufactured by stacking the screen electrode 11 at a predetermined position on the insulating layer 9 of the alumina ceramic multilayer plate fired as described above. This screen electrode 11 is formed by photo-etching a stainless steel plate with a thickness of 30 μm, for example, to form a plurality of openings 12 with a diameter of 150 μm.
12... is formed by opening it. Above screen electrode 1
1, as shown in FIG. 2, control electrodes 5a, 5b, 5c
It is attached to the alumina ceramic multilayer plate by means of adhesion or the like via an appropriate spacer member so that the distance from... is constant.

As shown in FIG. 2, the recording head 1 applies a high frequency high voltage between the drive electrodes 3a, 3b, 3c, . . . , 5b, 5c, . . . by a power source 21, and a DC voltage by a DC power source 22 to the screen electrode 11. By doing this, the drive electrodes 3a, 3 to which a voltage is selectively applied
A creeping corona discharge is generated in the space region 7 between the control electrodes 5a, 5b, 5c, . . . , and the control electrodes 5a, 5b, 5c, . ... and the screen electrode 11 to accelerate or absorb the ions, control ion emission, and form an electrostatic latent image.

In FIG. 2, numeral 23 indicates a dielectric drum on which an electrostatic latent image is formed. Note that the distance between the screen electrode 11 and the dielectric drum 23 is 100 to 400 μm, preferably 2 μm.
It is set to 00 to 300 μm.

In this way, the insulating substrate 2 and the insulating layer 4 of the recording head 1.
Since the insulating substrate 2 and the insulating layer 4.9 made of a ceramic material have sufficient withstand voltage and discharge resistance, and are inexpensive and easily available. Further, since the insulating substrate 2 and the insulating layer 4.9 are formed of a ceramic material, the recording head 1 can be manufactured by a manufacturing method suitable for mass production such as a molding process or a firing process of ceramic materials. A low-cost electrostatic latent image forming device can be provided.

Furthermore, since the insulating substrate 2 and the insulating layer 4.9 are made of ceramic material, they have strength that can withstand ion bombardment, stability that can withstand chemical reactions caused by active substances and plasma generated by discharge, and temperature rise of the heater. It is possible to provide a highly reliable electrostatic latent image forming device having heat resistance against heat and the like. Further, since the insulating substrate 2 and the insulating layer 4.9 are formed of a ceramic material, the insulating substrate 2 and the like can be manufactured according to predetermined shapes and characteristics, and uniform discharge can be performed.

Further, the drive electrode 3a%3bN3c・
... and control electrodes 5a, 5b, 5c... are connected to the insulating substrate 2.
Since the structure is such that a conductive paste made of tungsten or the like is printed by screen printing or the like on a ceramic green sheet that constitutes the insulating layer 4, etc., immediately after printing on the ceramic green sheet, Tungsten paste electrodes 3a, 3b, 3c...
5a, 5b, 5c, etc., the binder of the paste is appropriately absorbed by the ceramic sheet and does not flow, so that the edges of the electrodes are formed sharply. Therefore, occurrence of abnormal discharge at local protrusions of the electrodes and non-uniformity of discharge due to differences in the shape of the electrodes are eliminated, and an even electrostatic latent image can be formed.

〔Effect of the invention〕

The present invention has the above configuration and operation, and the electrostatic latent image forming apparatus according to claims 1 and 2 has the above configuration and operation, and the insulating layer is formed of a ceramic material. Therefore, it is possible to provide an electrostatic latent image forming apparatus that has sufficient voltage resistance and discharge resistance, and can use inexpensive and easily available materials. Further, since the insulating layer and the electrodes can be formed by screen printing, it is possible to provide an inexpensive electrostatic latent image forming device that can be manufactured using a manufacturing method suitable for mass production. Furthermore, since the insulating layer and electrode are integrally manufactured by sintering, they have the strength to withstand ion bombardment, the stability to withstand chemical reactions caused by active substances and plasma generated by discharge, and the heat resistance to rise in temperature of the heater. Therefore, it is possible to provide a highly reliable electrostatic latent image forming device with excellent properties and the like. In addition, since the insulating layer is made of a ceramic material, a sharp electrode pattern can be formed on it, which allows for uniform discharge and eliminates image unevenness in the electrostatic latent image that is formed. It is possible to provide an electrostatic latent image forming device that does not cause seeding.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view showing an embodiment of the electrostatic latent image forming device according to the present invention, FIG. 4 is a partially cutaway plan view of FIG. 3, FIG. 5 is a partially cutaway plan view of the conventional device, and FIG. 6 is the same. FIG. 2 is a cross-sectional view of the main parts of the device. [Explanation of symbols] 1... Recording head 2... Insulating substrate 3... Drive electrode 4... Insulating layer 5... Control electrode 7... Spatial region for ion generation 9... Insulating layer 11...Screen electrode 12...Opening part 5 diagram 4 Figure 1 Figure 7: Ion generation electrode diagram 6 Figure 11: lSb

Claims (3)

[Claims] (1) comprising a plurality of first electrodes, a plurality of second electrodes, and an insulating layer, the first electrodes and the second electrodes are provided in a matrix with the insulating layer sandwiched therebetween; The second electrode is configured to cover the insulating layer in an electrostatic latent image forming apparatus having a spatial region in which creeping corona discharge is caused by applying a voltage between the first electrode and the second electrode. An electrostatic latent image forming device characterized in that it is formed of a ceramic material. (2) A plurality of first electrodes, a plurality of second electrodes, and a third
an electrode, a first insulating layer, and a second insulating layer,
The first electrode and the second electrode are provided in a matrix with the first insulating layer in between, and the second electrode applies a voltage between the first electrode and the second electrode. The third electrode is provided with the second insulating layer interposed between the third electrode and the second electrode, and the third electrode is provided with the second insulating layer interposed between the third electrode and the second electrode. The electrode is an electrostatic latent image forming device comprising an ion extraction area for extracting ions generated by the creeping corona discharge, wherein the first and second insulating layers are formed of a ceramic material. Latent image forming device. (3) An electrostatic latent image forming device according to claim 1 or 2, wherein the electrode and the insulating layer are integrally manufactured by sintering.