JPH1016282A - Fabrication of ion flow electrostatic recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for fabricating an ion flow electrostatic recording head in which an image can be formed precisely by forming an insulator layer having micro surface roughness and uniform thickness. SOLUTION: After forming a first electrode 12 of thin titanium film on an insulating substrate 11, a dielectric layer 13 is formed on the side of the insulating substrate 11 where the first electrode 12 is formed and then a second electrode 14 having an opening 14a is patterned thereon. Subsequently, it is coated with an additive heat resistant polyimide resin insulator paste having viscosity of 20000cps by screen printing and an insulator paste layer 15a is formed. It is then dried using a solvent and pressed by a high rigidity planar die 16 having surface roughness of 0.2μm or below while heating up to a higher temperature region than the setting point. After the insulator paste layer 15a is cured, the planar die 16 is removed and an insulator layer 17 of 50μm thick having an opening 17a is formed by patterning. Finally, a third electrode 18 previously formed with an opening 18a is applied onto the insulator layer 17 thus producing an ion flow electrostatic recording head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an ion flow electrostatic recording head used for electrostatic printing and copying.

[0002]

2. Description of the Related Art Generally, for example, in electrostatic printing and the like,
2. Description of the Related Art There is known an electrostatic recording apparatus that generates ions having a high current density, extracts the ions, selectively applies the ions to a member to be charged, and charges the member to be charged in an image-like manner.

[0003] As an ion flow electrostatic recording head used in this electrostatic recording apparatus, one having a configuration as shown in FIGS. 3A and 3B is known. In the figure, reference numeral 1 denotes an insulating substrate, on which a plurality of first electrodes 2 extending substantially linearly in the same direction and arranged substantially in parallel are provided. These first electrodes 2 are fixed to one surface of the dielectric layer 3. A plurality of second electrodes 4 extending in a direction different from the direction in which the first electrodes 2 extend are fixed to the other surface of the dielectric layer 3 with an adhesive 8. A plurality of first electrodes 2 and a plurality of second electrodes 4 form a matrix. Further, an opening 4a for ion generation is formed at a portion corresponding to the intersection of the matrix of the second electrode 4. A third electrode 6 is disposed on the opposite side of the second electrode 4 from the first electrode 2 with an insulator layer 5 interposed therebetween. In the insulator layer 5 and the third electrode 6, openings 5a and 6 corresponding to the opening 4a of the second electrode 4 are provided.
The openings 5a and 6a form an ion flow passage 7.

In the ion flow electrostatic recording head thus configured, the first electrode 2 and the second electrode 4
By applying a high voltage alternately between the first electrode 2 and the second electrode 4 corresponding to a selected portion of the matrix of the above, the opening 4a of the second electrode 4 opposed to that portion
In the vicinity, positive and negative ions are generated. Also, the second electrode 4
And a third electrode 6, a bias voltage is applied, and only ions determined by the polarity are selectively extracted from the generated ions, pass through the ion flow passage 7, and face the third electrode 6. The member to be charged, which is arranged in a position, can be partially charged. Therefore, by selectively driving the first and second electrodes having a matrix structure, electrostatic recording using dots can be performed.

[0005] The dielectric material forming the dielectric layer 3 of the ion flow electrostatic recording head configured as described above is required not to cause dielectric breakdown even at a high voltage applied for generating ions. Further, the dielectric layer 3 needs to have a thickness enough to efficiently generate ions and withstand dielectric breakdown, so that a material having a high dielectric constant is suitable. For example, Japanese Patent Application Laid-Open No. 2-153760 discloses a dielectric layer made of a mixture of a titanium-modified powder in a silicone-modified polyester alkyd resin. In the above disclosure, the first electrode is made of copper foil, and the second and third electrodes are made of stainless steel sheet, and the second electrode is fixed to the dielectric layer. Silicone-based pressure-sensitive adhesives are used as adhesives to be bonded and adhesives for fixing the third electrode to the insulator layer. Further, a dry film solder mask is used as a material of the insulator layer.

[0006]

By the way, when the ion flow electrostatic recording head is driven, electric discharge between the first electrode 2 and the second electrode 4 under a high voltage causes peripheral members,
In particular, an insulator layer 5 existing between the second electrode 4 and the third electrode 6
Is exposed to activated large amounts of ions. JP-A-2-
As disclosed in JP-A-153760, when a dry film solder mask is used for the insulator layer 5, since the material of the solder mask is an acrylic resin,
In a relatively short time, the acrylic resin forming the insulator layer is attacked by active ions, the polymer chains are cut apart, and the powder gradually blows from the surface of the opening 5a of the insulator layer 5. Can be seen. This powder adheres to the periphery of the opening 6a of the third electrode 6 with time and gradually closes the opening 6a. Also, the second electrode 4 is not provided and the first electrode 2
In the non-ion generating portion where the third electrode 6 and the third electrode 6 face each other with the dielectric layer 3 and the insulator layer 5 interposed therebetween, the interface between the dielectric layer 3 and the insulator layer 5 and the end face of the third electrode 6 Discharge is likely to occur even on the surface of the insulator layer 5 in the vicinity, and when a dry film solder mask as disclosed in JP-A-2-153760 is used as the insulator layer, the material becomes The acrylic resin cannot withstand the high voltage between the first electrode 2 and the third electrode 6 and gradually discharges and erodes,
Eventually, a phenomenon leading to dielectric breakdown is observed.

Therefore, the opening diameter of the opening 6a of the third electrode 6 is reduced with time, making it difficult to control the generated ions. The electrical characteristics in each opening 4a of the second electrode 4 change, and there is a portion where ions cannot be generated uniformly, or a leakage and short-circuit phenomenon occurs, thereby deteriorating the image quality of an electrostatically recorded image. However, there is a problem that a high-definition image cannot be obtained.

Further, as a result of our intensive studies, it has been found that the insulator layer 5
Was found to be the most important factor that causes the variation in the amount of ions generated from each opening.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems in the conventional ion flow electrostatic recording head. The objects of the invention described in each claim are as follows. According to the first aspect of the present invention, there is provided a method of manufacturing an ion flow electrostatic recording head capable of forming a high-definition image by minimizing the roughness of the surface of an insulator layer and removing unevenness in the thickness of the insulator layer. The purpose is to provide. According to a second aspect of the present invention, in the method for manufacturing an ion flow electrostatic recording head according to the first aspect, the insulator layer is not deteriorated even under a long-time discharge, and the discharge in a portion other than the ion generating portion. It is an object of the present invention to provide a method for manufacturing an ion flow electrostatic recording head capable of forming a high-definition and high-definition image without causing a short circuit or a short circuit phenomenon due to the above. A third object of the present invention is to enable the method for manufacturing an ion flow electrostatic recording head according to the second embodiment to be performed with a small number of man-hours. According to a fourth aspect of the present invention, there is provided the method of manufacturing an ion flow electrostatic recording head according to the second or third aspect, further comprising a step of shrinking at the time of high-temperature curing to cause deformation or damage to another resin material. It is an object of the present invention to provide a method of manufacturing an ion flow electrostatic recording head having an insulator layer which can be cured and formed in a low temperature range and has a high corona discharge resistance. According to a fifth aspect of the present invention, in the method for manufacturing an ion flow electrostatic recording head according to the first aspect, the insulator layer does not deteriorate even under a long-time discharge, and a leakage due to discharge in a portion other than the ion generating portion. It is an object of the present invention to provide a method of manufacturing an ion flow electrostatic recording head capable of forming a high-definition and high-definition image without causing a short circuit phenomenon.

[0010]

According to a first aspect of the present invention, a plurality of first electrodes extending in one direction and in parallel on an insulating substrate are provided. A plurality of second electrodes extending in a direction intersecting with the first electrode and forming a matrix with the first electrode, and an opening formed in a portion corresponding to the intersection of the matrix; A third electrode disposed on a side opposite to the first electrode and having an opening formed at a portion corresponding to an intersection of the matrix, and a dielectric provided between the first electrode and the second electrode; Production of an ion flow electrostatic recording head comprising a layer and an insulator layer provided between the second electrode and the third electrode and having an opening at a portion corresponding to an intersection of the matrix. In the method, a thickness of at least 30 μm and a thickness of 150 μm An uncured insulator paste is applied below to form an insulator paste layer, and before the curing is completed, the insulator paste layer is pressed under heating by a flat mold having a surface roughness of 0.2 μm or less, and The method is characterized by comprising a step of forming the insulator layer having a thickness variation of 0.2 μm or less by terminating curing after releasing the mold.

In this way, the insulating paste layer is formed by pressing the insulating paste layer with a smooth planar type under heating in a flowable and deformable state before being formed and cured by the insulating paste. An insulator layer having a small surface roughness and no thickness unevenness such as surface undulation can be formed,
As a result, an ion flow electrostatic recording head capable of forming a high-definition image can be obtained.

According to a second aspect of the present invention, in the method for manufacturing an ion flow electrostatic recording head according to the first aspect, a paste containing a polyimide resin as a main component is used as the insulating paste. By forming the insulator layer using a paste containing a polyimide resin as a main component in this manner, the insulator layer has a small surface roughness and is not uneven in thickness, and is further subjected to a long-time discharge. It is possible to form an insulator layer that does not deteriorate, does not change the opening diameter of the opening of the third electrode, and does not cause an electric leakage or a short circuit phenomenon due to discharge in a portion other than the ion generating portion. Thus, an ion flow electrostatic recording head capable of forming a high-definition image with high durability can be obtained.

According to a third aspect of the present invention, there is provided a method of manufacturing an ion flow electrostatic recording head according to the second aspect, wherein the paste mainly composed of a polyimide resin used as the insulating paste has a viscosity of 5,000 cps to 150,000 cps. Is used. By using a polyimide resin paste having such a viscosity, several hundreds of
Compared to a thick film uniform film formation method in which a low viscosity solution of about cps is repeatedly applied, dried, and cured several tens of times by spin coating, dipping, etc., it is smoother in a thick film area with less man-hours, An insulator layer made of a polyimide resin having almost no variation in film thickness can be easily formed.

According to a fourth aspect of the present invention, in the method of manufacturing an ion flow electrostatic recording head according to the second or third aspect,
A solvent-soluble polyimide resin is used as the polyimide resin for forming the insulator layer. As a result, curing and film formation can be performed in a low temperature range, so that shrinkage and deformation that occur during high temperature curing do not occur, and other resin materials are not damaged, and a highly durable insulator film. Can be formed.

According to a fifth aspect of the present invention, in the method of manufacturing an ion flow electrostatic recording head according to the first aspect, a paste containing a ceramic material as a main component is used as the insulating paste. . By forming the insulator layer using a paste containing a ceramic material as a main component, the insulator layer is not deteriorated even under a longer-time discharge, and the ion generation is less than when a polyimide resin paste is used. It is possible to form a highly durable insulator layer that does not cause a short circuit or a short circuit due to discharge in a part other than the part.

[0016]

Next, an embodiment will be described. 1 and 2 are cross-sectional views showing manufacturing steps for explaining a first embodiment of a method for manufacturing an ion flow electrostatic recording head according to the present invention. First, as shown in FIG. 1A, a quartz substrate having a thickness of 0.6 mm and a polished surface is prepared as an insulating substrate 11, and the surface of the insulating substrate 11 is
After the surface is cleaned, a titanium film having a thickness of 1 μm is formed on the entire surface by sputtering. Subsequently, the first electrode 12 is formed on the insulating substrate 11 by subjecting the titanium thin film layer on the insulating substrate 11 to photoetching. next,
As shown in FIG. 1B, a 4 μm-thick silicon nitride film is formed on the insulating substrate 11 on the pattern forming side of the first electrode 12 by a plasma CVD method to form a dielectric layer 13. Further, a molybdenum film having a thickness of 1 μm is formed on the formed dielectric layer 13 by sputtering, and as shown in FIG. Two electrodes 14 are formed by lamination. In the second electrode 14, a pattern of openings 14a of the plurality of second electrodes 14 is formed.

Subsequently, as shown in FIG. 1D, the surfaces of the insulating substrate 11, the dielectric layer 13 and the second electrode 14
An insulation paste made of an additional heat-resistant polyimide resin of 00 cps is applied by screen printing to form an insulation paste layer 15a before curing. Next, the insulator paste layer 15a
After drying the solvent, in parallel with the insulating substrate 11 and the dielectric layer 13,
The surface of the insulating paste layer 15a is dried while being heated to a temperature higher than the softening point of the insulating paste layer 15a by a high-rigidity flat mold 16 having a surface roughness of 0.2 μm or less and a release treatment of the surface. Press. As a result, as shown in FIG. 2A, a smooth and dried insulator paste layer 15 having a thickness variation of 0.2 μm or less is formed, and then cured under predetermined curing conditions, and then gradually cooled. After the flat mold 16 is removed, patterning is performed by photoetching to form an opening 17 having a thickness of 50 μm as shown in FIG.
An insulator layer 17 having a is formed. When a condensation type polyimide resin is used as a material of the polyimide resin insulating paste, a by-product is generated during the curing reaction, and a defect is easily generated in the formed insulating layer. 16 is removed.

The thickness of the insulating layer 17 is preferably 30 μm or more and 150 μm or less in view of the electrical specifications for ion generation and control of the ion flow electrostatic recording head. That is, if the thickness is less than 30 μm, the generated ions easily leak and cannot be controlled. If the thickness exceeds 150 μm, the electric field in each of the openings 14 a and 17 a and the opening of the third electrode described below is weakened, and the generated ions are generated. It is difficult to control the discharge and stop of ions from the opening of the third electrode. The insulating paste made of polyimide resin used when forming the insulating layer 17 preferably has a viscosity of 5000 cps or more and 150,000 cps or less. This is because if it is less than 5000 cps, it becomes difficult to form a thick film of 30 μm or more, while if it exceeds 150,000 cps, it depends on the degree of thixotropic property imparted.
This is because the smoothing operation by the above makes it difficult to achieve smoothing.

Next, as shown in FIG. 2C, the openings 18a corresponding to the openings 14a of the second electrodes 14 are formed.
.. the third electrode 18 previously formed with the opening of the insulator layer 17
The ion flow electrostatic recording head is completed by overlapping the insulating layer 17 with the opening 17a of the third electrode 18 aligned with the opening 17a. The third electrode 18 is formed by electroforming nickel foil, and the insulator layer 17 and the third electrode 18 are formed.
And the third electrode 18
May be superimposed on the insulator layer 17 and then a single-sided tape may be attached over the third electrode 18 and the insulator layer 17 to fix them together. Further, the third electrode 18 is directly on the insulator layer 17,
It may be formed and patterned by a thin film technique such as sputtering.

The following effects can be obtained by manufacturing the ion flow electrostatic recording head as described above. That is, the insulator layer of the ion flow electrostatic recording head
At the time of manufacturing 17, the dielectric layer 13 and the second electrode 14
A polyimide resin insulating paste of 5000 cps or more and 150,000 cps or less is applied, and after drying with a solvent, is pressed under heating with a smooth flat mold 16 and then cured, thereby forming an insulating layer 17. It is easy to form a thick insulating layer of 30 μm or more and 150 μm or less with a thickness of not more than μm, and it has high corona discharge resistance.
a is hardly deteriorated by the activated ions, and is hardly deteriorated by the discharge in the non-ion generating portion, so that the initial electric characteristics can be maintained for a long time. As a result, a highly durable ion flow electrostatic recording head that can maintain the initial high image quality for a long time can be realized.

In the present embodiment, the addition type polyimide resin is used as the material for forming the insulator layer. However, in order to make the patterning by photo-etching in a later step easier, Is a negative photosensitive polyimide resin that is firm but very resistant to corona discharge, for example, “TBb-1150N (s)” (trade name,
An insulating layer with improved durability can also be formed by adding a polyimide resin filler to Nitto Denko Corporation and increasing the viscosity to tens of thousands cps.

Next, a second embodiment will be described. In this embodiment, a solvent-soluble polyimide resin is used instead of the additional polyimide resin as a material for forming the insulator layer in the first embodiment. As the solvent-soluble polyimide resin used in the present embodiment, for example, “CRI-100” (trade name, manufactured by Shin Nippon Steel) is available, and 35 wt% in m-cresol.
The melted paste having a viscosity of about 50,000 cps is applied as an insulating paste by screen printing in the same manner as in the manufacturing method of the first embodiment, and the solvent is volatilized off to form a dry insulating paste layer. Then, similarly to the manufacturing method of the first embodiment, the insulating layer having a thickness variation of 0.2 μm or less and a thickness of 50 μm is formed by pressing with a smooth flat mold under heating at 200 ° C. or more.

According to the present embodiment, similarly to the first embodiment, a thick insulator layer having small thickness variation and a high corona discharge resistance can be formed. The parts are hardly deteriorated by activated ions, and the non-ion generating parts are hardly deteriorated by electric discharge, so that the initial electrical properties can be maintained for a long time, and as a result, the initial high image quality can be maintained for a long time. An ion flow electrostatic recording head is obtained.

Further, since the insulator layer can be formed at a relatively low temperature, the film can be formed in a short time, and there is no thermal damage to a layer below the insulator layer, and the material must be cured at a high temperature. In the case of ordinary polyimide resin which is not to be used, it is possible to avoid problems such as distortion and deformation of the insulator layer, which are caused by cooling a high-temperature cured resin to around room temperature. Further, restrictions on other constituent materials around the insulator layer are reduced, and a less expensive material and manufacturing process can be adopted.

Next, a third embodiment will be described. This embodiment is different from the first embodiment in that a heat-resistant inorganic binder such as “Redproof MR- 10
A ceramic insulating film is formed using "0" (manufactured by Hotken Co., Ltd.) as an insulating paste, and this is photoetched and patterned to form an insulating layer having a thickness of 50 μm.

The heat-resistant inorganic binder used in the present embodiment is obtained by dissolving a silicon compound as a main component in water, and mixing various kinds of ceramic fillers such as alumina, zirconia, fused silica, mullite, and mica. After the application, the coating is dried at room temperature for 30 minutes, and then pressed in a flat mold under heating at 100 ° C. to smooth it, as in the first embodiment. Thereafter, the substrate is allowed to cool to room temperature and then left for two days to complete curing and form an insulator layer. Since the method of forming the insulator layer is performed at around room temperature, a thick film can be formed without a large residual stress in the film or a thermal load on peripheral constituent materials.

As described above, according to the present embodiment, similarly to the first embodiment, the thick-film insulator layer can be formed without deformation such as warpage and the like. Higher resistance to heat and corona discharge and higher corona discharge resistance than polyimide resin, which makes it difficult for the openings in the insulator layer to deteriorate due to activated ions. Therefore, it is possible to maintain an initial electrical characteristic for a long time, and as a result, obtain a highly durable ion flow electrostatic recording head capable of maintaining an initial high image quality for a long time.

Further, since the insulator layer can be formed at a relatively low temperature near normal temperature, there is no thermal damage and the coefficient of thermal expansion is close to that of the material of the insulating substrate and the dielectric layer. For this reason, with a normal polyimide resin that must be cured at high temperatures, it is possible to avoid problems such as distortion and deformation of the insulating layer surface layer and the insulating layer caused by cooling the high-temperature cured resin to around room temperature. Restrictions on other constituent materials around the layer are reduced, and less expensive materials and manufacturing processes can be adopted.

[0029]

As described above with reference to the embodiment, according to the first aspect of the present invention, an insulator layer having a small surface roughness and having no unevenness in thickness such as undulation of the surface is formed. As a result, an ion flow electrostatic recording head capable of forming a high-definition image can be obtained. According to the second aspect of the present invention, since the insulating layer is formed using the polyimide resin insulating paste, it is not deteriorated under a long-time discharge, and has high durability and high definition image formation. Is obtained. According to the third aspect of the present invention, since the insulating layer is formed using a polyimide resin insulating paste having a viscosity of 5,000 to 150,000 cps, the polyimide resin is smooth with little man-hour and has almost no variation in film thickness. Made of an insulator layer. According to the invention described in claim 4, curing and curing in a low temperature range.
Since the film can be formed, shrinkage or deformation that occurs during high-temperature curing does not occur, and another resin material is not damaged, so that a highly durable insulator layer can be formed.
According to the fifth aspect of the present invention, a highly durable insulator layer can be formed without deterioration even under long-time discharge.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing process for describing a first embodiment of a method for manufacturing an ion flow electrostatic recording head according to the present invention.

FIG. 2 is a view showing a manufacturing process subsequent to the manufacturing process shown in FIG. 1;

FIG. 3 is a diagram showing a configuration example of a conventional ion flow electrostatic recording head.

[Explanation of symbols]

 11 Insulating substrate 12 First electrode 13 Dielectric layer 14 Second electrode 14a Opening 15 Smooth insulator paste layer 15a Insulator paste layer 16 Planar type 17 Insulator layer 17a Opening 18 Third electrode 18a Opening

Claims (5)

[Claims] A plurality of first electrodes extending in one direction and in parallel on the insulating substrate; and a plurality of first electrodes extending in a direction intersecting the first electrodes, forming a matrix with the first electrodes. A plurality of second electrodes having openings formed at portions corresponding to intersections of the matrix;
A third electrode disposed on the opposite side to the electrode and having an opening formed in a portion corresponding to the intersection of the matrix;
An opening is formed at a portion corresponding to an intersection of the matrix and a dielectric layer provided between the first electrode and the second electrode and provided between the second electrode and the third electrode; Forming an insulator paste layer on the second electrode by applying an uncured insulator paste having a thickness of 30 μm or more and 150 μm or less on the second electrode. Surface roughness of 0.2 before
forming the insulator layer having a thickness variation of 0.2 μm or less by pressing the insulator paste layer under heating with a flat mold having a thickness of 0.2 μm or less, and releasing the flat mold after completion of curing. A method for manufacturing an ion flow electrostatic recording head, comprising: 2. The method according to claim 1, wherein a paste containing a polyimide resin as a main component is used as the insulating paste. 3. The method according to claim 2, wherein the insulating paste containing the polyimide resin as a main component has a viscosity of 5000 cps or more and 150,000 cps or less. 4. The method according to claim 2, wherein the polyimide resin is a solvent-soluble polyimide resin. 5. The method according to claim 1, wherein a paste containing a ceramic material as a main component is used as the insulating paste.