JPH08169137A - Charge generation control element for electrostatic image-forming apparatus and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a charge generation control element for an electrostatic image forming apparatus in which a step due to a line voltage is flattened and the durability of a first insulating film near the line electrode edge is improved and a method for manufacturing the element. CONSTITUTION: A charge generation control element comprises a line electrode 102 embedded in the surface of a board 101 made of quartz, etc., a first insulating film 103 formed on the surfaces of the electrode 12 and the board 101, a finger electrode 104 formed on the upper part of the film 103 and having a finger hole 107 for generating charge at a center, and a screen electrode 106 formed on the surface of the electrode 104 via a second insulating film 105 having a hole for passing charge at a center and having a screen hole 108 for discharging the charge at the center.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge generation control element for an electrostatic image forming apparatus used for electrostatic printing and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a charge generation control element utilizing corona discharge has been used as a method for forming a latent image by electrostatic charges on a dielectric recording body by the principle of transferring charges directly onto the dielectric recording body and depositing them. Is disclosed in Japanese Patent Publication No. 2-62862, and such a charge generation control element is
A method of forming with high precision using semiconductor microfabrication technology is
It is proposed in Japanese Patent Application No. 6-288580, which is the application of the present applicant.

FIG. 13 is a perspective view showing a part of a configuration example of a conventional charge generator for an electrostatic image forming apparatus in a cutaway manner. FIG.
In the figure, reference numeral 100 denotes one charge generation control element, and the charge generator is configured by arranging a large number of charge generation control elements 100 one-dimensionally or two-dimensionally. The charge generation control element 100 includes a substrate 101 made of quartz or glass, a line electrode 102 made of metal, a first insulating film 103, a finger electrode 104 made of metal, a second insulating film 105, and a screen electrode. 106 and the finger electrode 104 and the screen electrode 106 have finger holes.
107 and a screen hole 108 are formed respectively.

Then, the charge generation control element 100 having the above structure
Each of the electrodes constituting is formed by forming a resist pattern on the metal film formed by a method such as a sputtering method or a vacuum deposition method, and then removing the portion not covered by the resist pattern by etching. Further, the first insulating film 103 is formed by plasma CVD (PlasmaChe
A material having a high electrostatic withstand voltage such as silicon oxide or silicon nitride formed by a method such as mical vapor deposition) is used. A resin having a high heat resistance such as polyimide is used for the second insulating film 105.

Next, the operation of the charge generation control element 100 thus constructed will be described. In FIG.
By applying an AC voltage between the line electrode 102 and the finger electrode 104, which are arranged with the first insulating film 103 sandwiched therebetween, a charge group is generated on the side wall of the finger hole 107 due to a corona discharge phenomenon. Negative charges having high mobility in this charge group are used for latent image formation. Finger electrode
When a positive potential higher than the potential applied to the finger electrode 104 is applied to the screen electrode 106 formed facing the 104 against the second insulating film 105, the negative charge generated by the corona discharge is generated. It is extracted from the screen hole 108 formed in the. The negative charges extracted from the screen holes 108 are accelerated toward a drum (not shown), which is a dielectric recording body, and are deposited on the drum to form a latent charge image. Conversely, when a negative potential is applied to the screen electrode 106 with respect to the finger electrode 104, extraction of negative charges from the screen hole 108 is blocked, and a latent image is not formed on the drum.

[0006]

By the way, when the conventional charge generation control element shown in FIG. 13 is driven, in addition to the fact that an electric field of several MV / cm 2 is generated inside the first insulating film 103, Since the surface of the first insulating film 103 is exposed to the plasma generated by the corona discharge, its temperature rises. Therefore, it is necessary to increase the thickness of the first insulating film 103 from the viewpoint of reliability. In view of time, film stress, discharge starting voltage, etc., the thickness cannot be increased without limit. Especially the line electrode 102
In addition to the generation of a high electric field in the vicinity of the edge 109, the step difference of the line electrode 102 causes the thickness of the first insulating film 103 to be thin, so that there is a problem that the dielectric breakdown is very likely to occur. .

The present invention has been made in order to solve the above problems in the conventional charge generation control element, and each of the inventions described in claims 1 to 3 is the first in the vicinity of the edge of the line electrode.
To provide a charge generation control element for an electrostatic image forming apparatus capable of improving the durability of the insulating film of
It is another object of the present invention to provide a method of manufacturing a charge generation control element for an electrostatic image forming apparatus capable of improving the durability of the first insulating film.

[0008]

In order to solve the above problems, the invention according to claim 1 provides a line electrode formed on the surface of an insulating substrate and a first line electrode formed on the surface of the line electrode. Of the insulator film, a finger electrode formed on the first insulator film and having a hole portion for charge generation in the central portion, and a hole portion for allowing charges to pass through to the central portion on the surface of the finger electrode. In a charge generation control element comprising a screen electrode having a hole for discharging charges in the central portion, which is formed via a second insulating film, which has the line electrode embedded in the insulating substrate. And
According to a second aspect of the present invention, the line electrode of the charge generation control element according to the first aspect is composed of a conductive film having a resistivity of 1 × 10 ⁻⁵ Ωcm or less, and the third aspect is According to the invention, the conductive film forming the line electrode of the charge generation control element according to claim 2 is made of aluminum, titanium,
It is formed of a metal film of copper, molybdenum, or tungsten.

By thus arranging the line electrode so as to be embedded inside the insulator substrate, a step does not occur near the edge of the line electrode, and as a result, the film thickness of the first insulating film at the edge of the electrode can be reduced. The decrease can be completely eliminated and the durability of the first insulating film can be significantly improved. Further, by constructing the line electrode using a conductive film having a low resistivity such as aluminum, the impedance of the line electrode can be reduced, and an electrostatic image forming apparatus for forming an image with excellent image quality without print unevenness is provided. A charge generation control element can be realized.

Further, the invention according to claim 4 is based on claims 1 to 3.
The method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to any one of claims 1 to 5, wherein a step of covering a region other than a planned line electrode formation portion on the surface of the insulating substrate with a photoresist, A step of forming a recess having the same depth as the thickness of the line electrode by etching in a portion of the substrate surface not covered with the photoresist, and removing the photoresist to form a metal film on the entire surface of the insulating substrate. Forming a line electrode by etching a portion of the surface of the metal film where a line electrode is to be formed with a photoresist, and removing a portion of the metal film not covered with the photoresist by etching. It is characterized by including a process. By forming the line electrode in such a process, the underlayer of the first insulating film is completely flattened without a significant change in the manufacturing process of adding one mask, and a static electrode having excellent durability is obtained. A charge generation control element for an image forming apparatus can be manufactured.

Further, the invention according to claim 5 adds a step of forming the line electrode by the method for manufacturing the charge generation control element according to claim 4 and then melting the line electrode at high temperature and cooling to room temperature. To produce a charge generation control element. By adding such a step, the sidewall of the recess formed on the insulator substrate and the line electrode embedded in the recess are brought into close contact with each other, and the first insulating layer formed on the insulator substrate and the line electrode is formed. The film structure of the film can be simplified and the number of steps required for forming the first insulating film can be reduced.

[0012]

EXAMPLES Next, examples will be described. FIG. 1 is a partially cutaway perspective view showing an embodiment of a charge generation control element for an electrostatic image forming apparatus according to the present invention. The same or corresponding members as those of the conventional example shown in FIG. Is attached.
The difference between this embodiment and the conventional example is that the line electrode 102
The other structure is the same as that of the conventional example in that it is embedded in the insulating substrate 101 and arranged. Thus, the line electrode 102
Since the insulating layer 101 is embedded in the insulator substrate 101, a step is not generated in the vicinity 109 of the edge of the line electrode 102, and the reduction of the film thickness of the first insulating film 103 at the edge portion of the line electrode 102 is completed. Therefore, the durability of the first insulating film can be significantly improved.

Next, a first embodiment of the method of manufacturing the charge generation control element according to the present invention will be described with reference to the manufacturing process diagrams shown in FIGS. First, as shown in FIG. 2, after forming a resist pattern 202 on a region other than a line electrode forming portion on a quartz (glass) substrate 201, the substrate 201 is isotropically or anisotropically etched to form the resist pattern 202. A recess 203 having the same depth as the thickness of the line electrode is formed on the substrate portion not covered with the resist pattern 202. It is sufficient for the depth t of the depression 203 to be in the range of 0.5 to 5.0 μm. Next, as shown in FIG. 3, after removing the resist pattern 202, an aluminum film 204 and a titanium film 205 are sequentially formed by a method such as sputtering or vacuum deposition, and then the aluminum film 204 formed in the recess 203.
A resist pattern 206 is formed on the titanium film 205. The titanium film 205 acts as an anti-hillock film for the aluminum film 204. Next, as shown in FIG. 4, of the aluminum film 204 and the titanium film 205, the resist pattern 20
By removing the part not covered by 6 by isotropic or anisotropic etching, the line electrode
Form 207.

Next, as shown in FIG. 5, a resist pattern
After removing 206, remove the silicon oxide film 208 by plasma CV
SOG (Spin On Gla
ss) The film 209 is formed to flatten the gap between the edge of the line electrode 207 and the recess 203. Further, a silicon oxide film 210 is formed on them by a method such as plasma CVD. Then, these silicon oxide films 208
, SOG film 209, and silicon oxide film 210 form a first insulating film. Next, as shown in FIG. 6, a finger electrode 211, a second insulating film 212 and a screen electrode 213 are sequentially formed on the silicon oxide film 210 to complete the charge generation control element.

The width of the resist pattern 206 is set to be 20 in order to stabilize the shape of the edge of the line electrode 207.
It is better to set the width narrower than 1 by about 1 to 2 μm. A titanium film for hillock prevention is formed on the surface of the aluminum film 204.
Instead of forming 205, part or all of the silicon oxide film 208 may be formed at a temperature of 200 ° C. or lower. In this embodiment, aluminum is used as the electrode material of the line electrode 207, but other materials such as copper, molybdenum and tungsten can also be used. However, in that case, it is desirable to use a material having a resistivity of 1 × 10 ⁻⁵ Ωcm or less. Although titanium is used as the aluminum hillock prevention film, other materials such as titanium nitride, molybdenum, and tungsten can be used as long as the material has the hardness required to prevent aluminum hillocks. Further, a composite film of a silicon oxide film and an SOG film is used as the first insulating film, but if the material has a high electrostatic withstand voltage, silicon nitride, TE is used.
Other materials such as a composite film of an OS (tetraethoxysilane) single layer film and an SOG film, or a composite film of a composite film of silicon oxide, silicon nitride, TEOS and an SOG film can be used. The thickness of the line electrode 207 is as shown in FIG.
By setting the value to be substantially equal to the depth t of 203, the flattening process can be optimized.

In the charge generation control element manufactured according to this embodiment, since the line electrode 207 is embedded in the insulating substrate 201, the first insulating film composed of the silicon oxide films 208 and 210 and the SOG film 209 is formed. In this case, the base can be completely flattened. Therefore, no step is formed near the edge of the line electrode 207. Therefore, the durability of the first insulating film is significantly improved.

Next, a second embodiment of the method of manufacturing the charge generation control element according to the present invention will be described with reference to the manufacturing process diagrams shown in FIGS. First, as shown in FIG. 7, a recess 302 is formed in a portion of the surface of a quartz (glass) substrate 301 where a line electrode is to be formed, and then an aluminum film 303 is formed on the entire surface of the substrate by the same method as in the first embodiment. . Next, FIG.
As shown in, the resist pattern 30 is
After forming 4, the line electrode 305 is formed by removing the portion not covered by the resist pattern 304 by etching. Next, as shown in FIG. 9, after removing the resist pattern 304, the line electrode 305 is melted by heating at a temperature near the melting point of aluminum, and then cooled to room temperature. Line electrode by this process
305 and depression 302 are in complete contact

Next, as shown in FIG. 10, a silicon oxide film 306 is formed as a first insulating film by a technique such as plasma CVD. The film formation temperature of the silicon oxide film 306 is set to prevent the generation of aluminum hillocks on the line electrode 305.
Set below 200 ℃. Next, as shown in FIG. 11, a charge generation control element is completed by sequentially forming a finger electrode 307, a second insulating film 308 and a screen electrode 309 on the silicon oxide film 306. The width of the resist pattern 304 is the same as in the first embodiment.
In order to stabilize the shape of the edge of No. 5, it is better to set the width of the recess 302 to be narrower by about 1 to 2 μm. Although a silicon oxide film is used as the first insulating film in this embodiment, a composite film of a silicon oxide film and an SOG film may be used as in the first embodiment, and a silicon nitride film, T
Other materials such as a composite film of a single layer film of EOS and an SOG film or a composite film of silicon oxide, silicon nitride, a composite film of TEOS and an SOG film can be used. Further, the thickness of the line electrode 305 is the same as that of the first embodiment, and the depression 302
It is desirable to set the value approximately equal to the depth of the.

Further, in this embodiment, after the step shown in FIG. 9, a metal film 310 of high hardness such as titanium is formed on the entire surface of the substrate as shown in FIG. 12, and a line electrode is formed by using a resist pattern 311. The metal film 310 can be patterned by etching so as to cover the aluminum surface of 305, and in this case, the silicon oxide film 30 serving as the first insulating film is formed.
6 does not necessarily need to be formed at a low temperature of 200 ° C. or lower, and the first insulating film can be formed under normal conditions. In addition, in this embodiment, the same effect as that of the first embodiment can be obtained, and further, since the structures of the first insulating film and the line electrode are simple, the number of steps required for manufacturing the element can be significantly reduced. Also has.

[0020]

As described above on the basis of the embodiments, according to the invention of claim 1, the base of the first insulating film formed between the line electrode and the finger electrode is completely planarized. In addition, it is possible to realize a charge generation control element for an electrostatic image forming apparatus having excellent durability, and it is possible to increase the thickness of the line electrode. It is possible to realize a charge generation control element for an electrostatic image forming apparatus in which unevenness is reduced and which can form an image with excellent image quality. According to the second and third aspects of the present invention, by using a material having high conductivity for the line electrode, the impedance of the line electrode can be reduced and an image of excellent image quality without print unevenness can be formed. A charge generation control element for an image forming apparatus can be realized. Further, according to the invention described in claim 4, the base of the first insulating film can be completely planarized by adding only one photomask and without significantly changing the manufacturing process. Further, according to the invention of claim 5, the film of the first insulating film formed on the sidewall of the recess formed on the insulating substrate and the line electrode buried in the recess are brought into close contact with each other. Since the structure can be simplified, there is an effect that the number of steps required for forming the first insulating film can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a charge generation control element for an electrostatic image forming apparatus according to the present invention.

FIG. 2 is a diagram showing a manufacturing process for explaining the first embodiment of the method for manufacturing the charge generation control element for the electrostatic image forming apparatus according to the present invention.

FIG. 3 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 2;

FIG. 4 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 3;

FIG. 5 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 4;

FIG. 6 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 5;

FIG. 7 is a diagram showing a manufacturing process for explaining the second embodiment of the method for manufacturing the charge generation control element for the electrostatic image forming apparatus according to the present invention.

FIG. 8 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 7.

9 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 8. FIG.

FIG. 10 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 9.

FIG. 11 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 10.

FIG. 12 is a diagram showing a process of a modification of the second embodiment of the manufacturing method shown in FIGS. 7 to 11.

FIG. 13 is a perspective view showing a part of a configuration example of a conventional charge generation control element for an electrostatic image forming apparatus in a cutaway manner.

[Explanation of symbols]

 100 Charge Generation Control Element 101 Substrate 102 Line Electrode 103 First Insulating Film 104 Finger Electrode 105 Second Insulating Film 106 Screen Electrode 107 Finger Hole 108 Screen Hole 109 Edge 201 Quartz (Glass) Substrate 202 Resist Pattern 203 Recess 204 Aluminum Film 205 Titanium film 206 Resist pattern 207 Line electrode 208 Silicon oxide film 209 SOG film 210 Silicon oxide film 211 Finger electrode 212 Second insulating film 213 Screen electrode 301 Quartz (glass) substrate 302 Dimple 303 Aluminum film 304 Resist pattern 305 Line electrode 306 First insulating film 307 Finger electrode 308 Second insulating film 309 Screen electrode 310 High hardness metal film 311 Resist pattern

Claims (5)

[Claims] 1. A line electrode formed on the surface of an insulator substrate, a first insulator film formed on the surface of the line electrode, and a first electrode film formed on the first insulator film at the center. A finger electrode having a hole for charge generation, and a hole for charge outflow in the center formed on the surface of the finger electrode through a second insulating film having a hole for allowing the charge to pass through in the center. A charge generation control element comprising a screen electrode having a portion, wherein the line electrode is embedded and arranged inside the insulator substrate. 2. The charge generation control element for an electrostatic image forming apparatus according to claim 1, wherein the line electrode is formed of a conductive film having a resistivity of 1 × 10 ⁻⁵ Ωcm or less. 3. The conductive film is aluminum, titanium,
The charge generation control element for an electrostatic image forming apparatus according to claim 2, wherein the charge generation control element is formed of a metal film of copper, molybdenum, or tungsten. 4. The method for manufacturing a charge generation control element for an electrostatic image forming apparatus according to claim 1, wherein a region other than a line electrode formation planned portion on the surface of the insulator substrate is photoed. A step of covering with a resist, a step of forming a recess having the same depth as the thickness of the line electrode by etching in a portion of the surface of the insulator substrate which is not covered with the photoresist, and removing the photoresist, A step of forming a metal film on the entire surface of the insulator substrate, a step of covering a line electrode formation planned region of the metal film surface with a photoresist, and a part of the metal film not covered with the photoresist are etched. And a step of forming a line electrode by removing the charge generation control element for an electrostatic image forming apparatus. Build method. 5. The charge generation control element for an electrostatic image forming apparatus according to claim 4, further comprising a step of melting the line electrode at a high temperature after forming the line electrode and then cooling the line electrode to room temperature. Production method.