JPH09146349A - Charge generator for electrostatic image forming device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a charge generator for an electrostatic image forming device which maintains the higher image quality than heretofore in spite of long-time driving and has high durability by forming protective insulating films consisting of inorg. materials on the surfaces of finger electrodes near finger holes. SOLUTION: After line electrodes 2 are formed, dielectric films 3 are formed of an inorg. material having high electrostatic voltage resistance and thereafter, the finger electrode films are formed. Next, the protective insulating film 11 consisting of the inorg. materials, such as SiO2 , SiOH, SiN, TiO2 , Al2 O3 and other oxides and nitrides, are formed by plasma CVD, atm. pressure CVD, sputtering method, etc., on the finger electrode films after the formation of these films. The surfaces of the finger electrodes 4 are provided with the protective insulating films 11 in such a manner, by which the erosion of the surfaces of the finger electrodes 4 induced by the corona charge groups generated by high-voltage driving and corona discharge is prohibited and the occurrence of electrode foreign matter is prevented.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art An apparatus for forming a latent image by electrostatic charge on a dielectric recording medium by using corona discharge and a method for manufacturing the same are disclosed in Japanese Patent Publication No. 2-62862. By applying the method, a method for forming a high-definition charge generator for an electrostatic image forming apparatus is disclosed in Japanese Patent Application No. 6-268.
No. 145, etc.

FIG. 18 is a diagram showing a cross-sectional structure of a charge generation control element which constitutes a conventional electrostatic image forming apparatus formed by using a semiconductor fine processing technique. Such a charge generation control element is one-dimensionally formed. Or by arranging in a two-dimensional form,
A charge generator for an electrostatic image forming device is configured. In FIG. 18, 1 is an insulating substrate made of quartz or glass, 2 is a line electrode made of a metal, 3 is a dielectric film made of an inorganic insulator, 4 is a finger electrode made of a metal, 5 is a finger hole, 6 is a polyimide, etc. Is a screen electrode made of metal, 8 is a screen hole, and 9 is a space formed in the insulating film 6 below the screen hole.

Next, the operation of the charge generation control element thus constructed will be described. In FIG. 18, an AC voltage is applied between the line electrode 2 and the finger electrode 4 which are arranged with the dielectric film 3 interposed therebetween. As a result, a charge group is generated in the finger holes 5 due to the corona discharge phenomenon.
Of this charge group, negative charges having high mobility are used for latent image formation. When a positive potential higher than the potential applied to the finger electrode 4 is applied to the screen electrode 7 formed facing the finger electrode 4 with the insulating film 6 interposed, the negative charges generated by the corona discharge pass through the space 9. It is extracted from the screen hole 8. The negative charges extracted by the screen holes 8 are discharged toward the drum 10, which is a dielectric recording body, and are deposited to form a latent image. On the contrary, when a negative potential is applied to the screen electrode 7 with respect to the finger electrode 4, extraction of negative charges from the screen hole 8 is blocked, and a latent image is not formed on the drum surface.

Next, a method of manufacturing the charge generator including the charge generation control element shown in FIG. 18 will be described. A line electrode material is deposited on the insulating substrate 1 such as quartz or glass by sputtering, vacuum deposition, plating or the like. The electrode material is a single layer metal such as Ti, TiN, Mo, W, Al or Cu, or a multi-layer metal in which Ti, TiN or the like is formed on Al, and the film thickness is about 0.5 to 2 .mu.m. Thereafter, the line electrode film is patterned by a photolithography method, and a portion not covered with the resist film is wet or R.I. I. E
The line electrode 2 is formed by removing it by dry etching such as (Reactive Ion Etching). After forming the line electrode 2, SiO ₂ , SiON, SiN, TiO ₂ , Al ₂
The dielectric film 3 is made of an inorganic insulating material having a high electrostatic withstand voltage such as O ₃ and plasma CVD (Plasma Chemical Vapor Deposition),
Atmospheric pressure Chemical Vapor De
position), a film is formed by a sputtering method or the like. In order to reduce the step difference of the underlying line electrode 2, an SOG (Spin On Glass) film is actually interposed in the dielectric film by a spin coating method, and the above-mentioned insulating material film is formed on the upper and lower parts of the film. (Not shown). As a result, the breakdown voltage between the line electrode and the finger electrode is improved, and further, the variation in the generated charge amount between the elements is reduced,
A charge generator for an electrostatic image forming apparatus having high definition image quality can be realized. The thickness of the entire dielectric film is about 3 to 10 μm.

After forming the dielectric film 3, the pad portion at the end of the line electrode 2 is opened (not shown). The opening method is such that a portion other than the pad portion forming region is covered with a resist film by photolithography, and the dielectric film in the pad portion forming region not covered with the resist film is wet-etched, dry-etched, or a combination of wet and dry is used. Then, the line electrode pad portion is opened.
After opening the line electrode pad portion, the finger electrode 4 is formed by the same manufacturing method as the line electrode 2. The electrode material is preferably a refractory metal such as Ti, TiN, Mo or W. The film thickness is about 0.5 to 3 μm, and the diameter of the finger hole 5 is about 15 μm.

After the finger electrodes 4 are formed, an insulating film 6 made of an organic insulating material such as polyimide is formed by spin coating or screen printing. Its film thickness is 50
μm or more is desirable. After forming the insulating film 6, the screen electrode 7 is formed on the insulating film 6 by the same manufacturing method as the line electrode or the finger electrode. Ti, Ti for electrode material
A refractory metal such as N, Mo or W, or a multi-layer metal covering Al and Cu on the upper part of the refractory metal is preferable. The film thickness is about 1 to 3 μm, and the diameter of the screen hole 8 is about 50 μm or less. After forming the screen electrode, the insulating film 6 other than the lower part of the screen electrode 7 is selectively removed by dry etching using plasma or wet etching in a chemical solution using the screen electrode 7 as a mask,
A space 9 below the screen hole is formed. Through the above steps, the charge generator including the charge generation control element shown in FIG. 18 is completed.

[0008]

By utilizing a semiconductor manufacturing method for manufacturing a charge generator, the above-mentioned Japanese Patent Publication No.
Compared with the conventional printing and pasting manufacturing method disclosed in No. 62862, it is possible to perform a large amount of fine processing, and a high-definition electrostatic image forming apparatus having excellent image quality can be realized. The conventional charge generator has the following problems.

First, in order to generate a charge group by corona discharge in the region of the finger hole 5, the line electrode 2
A high voltage of around 1000 V _pp is required between the finger electrode 4 and the finger electrode 4. Therefore, when driven for a long time, a high voltage is applied or a corona charge group generated in the vicinity of the side wall of the finger electrode erodes the finger electrode surface portion not covered by the insulating film in the vicinity of the finger hole, and the finger electrode 4 of the finger electrode 4 is eroded. Foreign matter is generated, and the foreign matter adheres to the surface of the dielectric film 3 in the finger hole region, the insulating film side wall, and the like. Due to this phenomenon, as the driving time elapses, the amount of electric charge extracted to the drum changes significantly, or the electric charge amount of each electric charge generation control element greatly varies, and the image quality deteriorates. Further, there is a problem that the life of the finger electrode is short and the durability is inferior.

Further, in the conventional manufacturing method, the insulating film 6 is etched by using the screen electrode 7 as a mask. However, since the insulating film 6 is as thick as 50 μm or more, the etching is performed for a considerably long time. become. The surface of the screen electrode serving as a mask is roughened or eroded due to long-time etching, which causes foreign matter on the screen electrode 7 to occur, and the side wall of the insulating film 6 or the dielectric film 3 in the finger hole region. On the surface of
The foreign matter adheres. Due to this phenomenon, the amount of charge extracted to the drum changes significantly, or the variation in the amount of charge of each charge generation control element becomes large, which causes a problem of deterioration in image quality.

The present invention has been made in order to solve the above problems in the conventional charge generator for an electrostatic image forming apparatus, and the surface portion of the finger electrode is not eroded even when driven for a long time. Provided are a charge generator for an electrostatic image forming apparatus capable of maintaining high image quality and high durability, and a method for manufacturing the same, and further a method for manufacturing a charge generator for an electrostatic image forming apparatus free from roughening and erosion of a screen electrode. The purpose is to provide.

[0012]

In order to solve the above problems, the invention according to claim 1 provides a line electrode formed on an insulating substrate, and a solid dielectric film formed on the surface of the line electrode. A finger electrode having a hole for charge generation at the center formed on the solid dielectric film, and a solid insulating film having a hole at the center for allowing charges to pass through are formed on the surface of the finger electrode. In addition, in the charge generator for an electrostatic image forming apparatus including a charge generation control element including a screen electrode having a hole for discharging charges in the center, in the charge generator for a static image forming device, the solid insulation film is formed on the surface of the finger electrode. And an insulating film made of an organic material such as polyimide formed on the protective insulating film. This prevents erosion of the finger electrode surface portion caused by high voltage driving and generated corona discharge charge groups, and provides a charge generator for an electrostatic image forming apparatus that has higher image quality and higher durability than conventional even for long time driving. Can be realized.

According to a second aspect of the present invention, in the charge generator for an electrostatic image forming apparatus according to the first aspect, the protective insulating film is formed of SiO ₂ , SiON, SiN, TiO ₂ , Al ₂ O ₃ , Ta ₂ O
It is composed of an inorganic insulating film such as ₅ . in this way,
By forming the protective insulating film with an inorganic insulating film such as SiO _2, it is possible to realize a charge generator for an electrostatic image forming apparatus which has higher image quality and higher durability even when driven for a long time.

According to a third aspect of the present invention, in the method of manufacturing the charge generator for an electrostatic image forming apparatus according to the first or second aspect,
After forming the finger electrode film on the solid dielectric film, a step of forming a protective insulating film on the finger dielectric film by plasma CVD, atmospheric pressure CVD, a sputtering method, and the like, and an electrode pad region on the protective insulating film. Except for the step of forming a resist pattern in the area corresponding to the finger electrode formation-scheduled area, and then selectively removing the protective insulating film and the finger electrode film in the area not covered by the resist pattern by wet or dry etching. And a step of forming a finger electrode having a protective insulating film on the surface thereof, and the invention according to claim 4 is the manufacture of the charge generator for an electrostatic image forming apparatus according to claim 1 or 2. In the method
A step of forming a finger electrode on the solid dielectric film, and then forming a protective insulating film made of a material different from that of the solid dielectric film on the finger electrode by plasma CVD, atmospheric pressure CVD, sputtering, or the like; A step of forming a resist pattern on a region corresponding to a finger electrode region excluding an electrode pad region on the protective insulating film, and then selecting the protective insulating film not covered with the resist pattern by wet or dry etching. And then forming a protective insulating film on the surface of the finger electrode. As a result, it is possible to easily manufacture a charge generator for an electrostatic image forming apparatus, which has sharper image quality, higher image quality, and higher durability than conventional ones even when driven for a long time.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a charge generator for an electrostatic image forming apparatus according to the first or second aspect,
After forming a finger electrode on the solid dielectric film and forming a protective insulating film on the surface of the finger electrode, a step of forming an insulating film made of an organic material such as polyimide by screen printing on the entire surface, and then processing the insulating film. A step of laminating a thin metal plate for a screen electrode on the upper part of the film with an adhesive, and then forming a resist pattern on the thin metal plate by a photolithography method, and anisotropically forming a thin metal plate in a region not covered with the resist pattern. And a step of selectively removing by dry etching to form a screen electrode, and the invention according to claim 6 is the method for manufacturing a charge generator for an electrostatic image forming apparatus according to claim 1 or 2. After forming a finger electrode on the solid dielectric film and forming a protective insulating film on the surface of the finger electrode, spin a photosensitive polyimide on the entire surface. Forming the insulating film by baking the film at 150 ° C., baking the film at around 150 ° C., processing the polyimide film by post-exposure development by photolithography, and then baking again at around 350 ° C. Next, a step of adhering a metal thin plate for a screen electrode on the upper part of the insulating film with an adhesive, and then forming a resist pattern on the metal thin plate by a photolithography method to form a metal thin plate in a region not covered with the resist pattern. And a step of selectively removing it by anisotropic dry etching to form a screen electrode. This eliminates the need to use the screen electrode as a mask in the conventional long-time etching process of the insulating film, so that the surface of the screen electrode is not roughened, and the foreign matter of the screen electrode caused by the erosion is not generated on the side wall of the insulating film. Or the phenomenon of sticking to the surface of the solid dielectric film in the finger hole area disappears,
It is possible to easily manufacture a charge generator for an electrostatic image forming apparatus having higher image quality and higher durability than ever before.

[0016]

Next, an embodiment will be described. FIG. 1 is a sectional view showing a first embodiment of a charge generator for an electrostatic image forming apparatus according to the present invention. The same components as those of the conventional example shown in FIG. The description is omitted. In the present invention, the protective insulating film 11 is newly formed on the surface of the finger electrode 4 near the finger hole 5. By providing the protective insulating film 11 on the surface of the finger electrode 4 in this way, the erosion of the surface of the finger electrode 4 caused by the corona charge group generated by high voltage driving or corona discharge is prevented, and the generation of electrode foreign matter is prevented. As a result, a charge generator for an electrostatic image forming apparatus, which has high image quality and high durability for a long time, can be obtained.

Next, a method of manufacturing the charge generator for an electrostatic image forming apparatus according to the first embodiment having such a structure will be described with reference to the manufacturing process diagrams shown in FIGS. First, as shown in FIG. 2, similarly to the conventional example, a line electrode material is formed on an insulating substrate 1 such as quartz or glass, and the line electrode film is patterned by a photolithography method and is not covered with a resist film. The line electrode 2 is formed by removing the portion by dry etching. After forming the line electrode 2, the dielectric film 3 is formed of an inorganic material having a high electrostatic breakdown voltage. After forming the dielectric film 3, the finger electrode film 4a is formed. The parameters such as the material and film thickness of each component are the same as the conventional ones, and thus the description thereof is omitted.

Next, after forming a finger electrode film 4a, as shown in FIG. 3, further SiO _2, SiO thereon
The protective insulating film 11 made of an inorganic material such as N, SiN, TiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ , and other oxides and nitrides is formed by the same method as the dielectric film 3, that is, plasma CVD, atmospheric pressure CVD,
A film is formed by a sputtering method or the like. The thickness of the protective insulating film 11 is
About 0.1 to 2 μm is desirable. Subsequently, as shown in FIG. 4, a resist film 12 is formed on the protective insulating film 11 by photolithography in a region corresponding to the finger electrode formation planned region excluding the electrode pad portion. Next, as shown in FIG. 5, the protective insulating film 11 in a region not covered with the resist film 12 is wet or R.V. I. E (Reactive Ion Etchi
ng) etc. to remove by dry etching. After that, using the resist film 12 or the protective insulating film 11 as a mask, the structure shown in FIG.
, The finger electrode film 4a other than the lower part of the protective insulating film 11 is formed by the same method as the etching of the line electrode film, that is, wet or R.I. I. E is removed by dry etching to form finger electrodes 4 having finger holes 5. After removing the finger electrode film by etching,
The resist film 12 may be peeled off or may be left as it is. Through the above steps, the protective insulating film 11 made of an inorganic material can be formed on the finger electrodes 4. After that, the insulating film 6 is formed, the screen electrode 7 is formed and processed, and the insulating film 6 is etched in the same manufacturing process as that of the conventional example, so that the charge generator of the first embodiment shown in FIG. To complete. The reason why the protective insulating film 11 is made of an inorganic material is that if an organic material is used, the protective insulating film is also etched in the last etching step of the insulating film 6.

Next, a second embodiment will be described with reference to the manufacturing process drawings shown in FIGS. The final structure of this embodiment is the same as that of the first embodiment, but the manufacturing process is different from that of the first embodiment. First, the finger electrode film 4
The process up to the film formation of a is the same as in the first embodiment. Next, as shown in FIG. 7, a resist film 12 is formed in the finger electrode formation planned region by photolithography. Subsequently, as shown in FIG. 8, the finger electrode film 4a not covered with the resist film 12 is removed by the same method as the etching of the line electrode to form the finger electrode 4. Next, as shown in FIG. 9, after removing the resist film 12, a protective insulating film 11 is formed by the same method as in the first embodiment. However, if the material of the protective insulating film 11 is the same as the material of the dielectric film 3, the dielectric film 3 is also removed when the protective insulating film 11 is removed by etching. It is necessary to use different materials. Next, as shown in FIG. 10, a resist film 12 is formed on the protective insulating film 11 in the same region as the finger electrodes 4 excluding the electrode pad portion by photolithography. Then, as shown in FIG. 11, a resist film
The protective insulating film 11 which is not covered with the dielectric film 3 is wet-etched with a large selection ratio to the dielectric film 3 or R. I. Remove with E. After that, the first manufacturing process shown in FIG.
A charge generator having the same structure as that of the above embodiment is completed.

As described above, in the manufacturing methods of the first and second embodiments, the insulating film is formed and processed in the same manner as the conventional manufacturing process, that is, the screen electrode is processed and formed after the insulating film is formed. After that, a method of etching the insulating film using the screen electrode as a mask is used. However, in the third and fourth embodiments described below, a manufacturing process of processing and forming the screen electrode after forming the insulating film is performed. It is used.

Next, the manufacturing method of the third embodiment will be described with reference to FIG.
~ It demonstrates using the manufacturing process drawing shown in FIG. After forming the protective insulating film 11 in the same manufacturing process as that of the first or second embodiment, as shown in FIG. 12, the insulating film 6 made of polyimide or the like is formed and processed by the screen printing method. Next figure
As shown in Fig. 13, Ti and Ti used as screen electrode materials
A thin metal plate 7a such as N, Mo, W, or SUS is attached to the upper portion of the insulating film 6 with an adhesive. Then, as shown in FIG. 14, by patterning a resist film corresponding to the screen electrode by a photolithography method and removing the metal thin plate 7a in a region not covered with the resist film by an anisotropic dry etching method, The screen electrode 7 having the screen hole 8 is processed and formed. What must be anisotropically etched here is that the film thickness of the metal thin plate 7a for the screen electrode is several tens of μm, which is considerably thicker than the screen electrode film formed by the sputtering method or the like. Therefore, an etching method that avoids side etching is desirable.

The above is the manufacturing process of the charge generator for the electrostatic image forming apparatus according to the third embodiment. By forming and processing the insulating film before forming the screen electrode in this way, By etching the insulating film for such a long time, it is possible to prevent the generation of foreign matter due to the surface of the screen electrode used as the mask being roughened or scraped. Therefore, it is possible to easily realize a charge generator for an electrostatic image forming apparatus having higher image quality than conventional ones.

Next, the manufacturing method of the fourth embodiment will be described with reference to FIG.
~ It demonstrates based on the manufacturing process drawing shown in FIG. As shown in FIG. 15, after forming the protective insulating film 11 by the manufacturing process of the first or second embodiment, the insulating film 6 is formed by spin coating with a material such as photosensitive polyimide. To do. At this time, the baking temperature after spin coating is 150 °
By setting the temperature around C, the insulating film 6 becomes a polyamide state. Next, the resist film 12 corresponding to the shape of the insulating film 6 is patterned by a photolithography method. In the developing process after exposure, the resist film 12 is formed by a developing solution.
The underlying insulating film 6 in the polyamide state is also etched. Then, as shown in FIG. 16, after the resist film 12 is peeled off, the insulating film 6 becomes a polyimide state by baking again at around 350 ° C. After that, Figure 17
As shown in, the screen electrode 7 having the screen hole 8 is formed by the same manufacturing method as that of the third embodiment. Through the above steps, a charge generator for an electrostatic image forming apparatus having the same effect as that of the third embodiment can be manufactured.

[0024]

As described above based on the embodiments, according to the inventions of claims 1 and 2, the protective insulating film made of an inorganic material is formed on the finger electrode surface in the vicinity of the finger holes. It is possible to realize a charge generator for an electrostatic image forming apparatus, in which erosion of the finger electrode surface caused by high voltage driving or corona discharge charge group is prevented, and which has higher image quality and higher durability than conventional even in long time driving. it can. According to the third and fourth aspects of the invention, the surface of the finger electrodes is not eroded even when driven for a long time, and the charge generator for an electrostatic image forming apparatus capable of maintaining high image quality and high durability is easily provided. It can be manufactured. According to the fifth and sixth aspects of the present invention, the surface of the finger electrode is not eroded even when it is driven for a long time, and the screen electrode can be prevented from being roughened or eroded, resulting in high image quality and high durability. It is possible to easily manufacture a charge generator for an electrostatic image forming apparatus capable of maintaining the above.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a part of a first embodiment of a charge generator for an electrostatic image forming apparatus according to the present invention.

FIG. 2 is a view showing a manufacturing process for describing the manufacturing method of the first embodiment shown in FIG. 1;

FIG. 3 is a view showing a manufacturing process following the manufacturing process shown in FIG. 2;

FIG. 4 is a view showing a manufacturing process following the manufacturing process shown in FIG. 3;

FIG. 5 is a view showing a manufacturing process subsequent to the manufacturing process shown in FIG. 4;

FIG. 6 is a view showing a manufacturing process subsequent to the manufacturing process shown in FIG. 5;

FIG. 7 is a diagram showing a manufacturing process for explaining a manufacturing method according to a second embodiment of the present invention.

FIG. 8 is a view showing a manufacturing process subsequent to 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 manufacturing process for explaining the manufacturing method according to the third embodiment of the present invention.

FIG. 13 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 12.

14 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 13.

FIG. 15 is a diagram showing a manufacturing step for explaining the manufacturing method according to the fourth embodiment of the present invention.

16 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 15.

FIG. 17 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 16.

FIG. 18 is a cross-sectional view showing a configuration example of a conventional charge generator for an electrostatic image forming apparatus.

[Explanation of symbols]

 1 Insulating substrate 2 Line electrode 3 Dielectric film 4 Finger electrode 4a Finger electrode film 5 Finger hole 6 Insulating film 7 Screen electrode 8 Screen hole 9 Space 10 Drum 11 Protective insulating film 12 Resist film

Claims (6)

[Claims] A line electrode formed on an insulating substrate;
A solid dielectric film formed on the surface of the line electrode, a finger electrode formed in the upper portion of the solid dielectric film, having a hole portion for charge generation in the center, and a surface of the finger electrode,
A charge generator for an electrostatic image forming apparatus having a charge generation control element formed of a screen electrode having a hole for discharging charges formed in the center through a solid insulating film having a hole for allowing charges to pass therethrough. In the above, the solid insulating film is formed by a protective insulating film formed on the surface of the finger electrode, and an insulating film formed on the protective insulating film and made of an organic material such as polyimide. A charge generator for an image forming device. 2. The protective insulating film is made of SiO ₂ , SiON, Si
The charge generator for an electrostatic image forming apparatus according to claim 1, wherein the charge generator is composed of an inorganic insulating film such as N, TiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ . 3. The method of manufacturing a charge generator for an electrostatic image forming apparatus according to claim 1, wherein a finger electrode film is formed on the solid dielectric film, and then a protective insulating film is formed on the solid dielectric film by plasma CVD. A step of forming a film by atmospheric pressure CVD, a sputtering method, etc., a step of forming a resist pattern in a region corresponding to a finger electrode formation planned region other than the electrode pad region on the protective insulating film, and then the resist pattern Selectively removing the protective insulating film and the finger electrode film in the uncovered region by wet or dry etching to form a finger electrode having a protective insulating film on the surface thereof. A method of manufacturing a charge generator for an electrostatic image forming apparatus. 4. The method of manufacturing a charge generator for an electrostatic image forming apparatus according to claim 1, wherein a finger electrode is processed and formed on the solid dielectric film, and then the solid dielectric film is formed on the finger electrode. Is a step of forming a protective insulating film made of a different material by plasma CVD, atmospheric pressure CVD, sputtering, etc., and a resist pattern is formed on the protective insulating film in a region corresponding to the finger electrode region excluding the electrode pad region. And a step of selectively removing the protective insulating film not covered with the resist pattern by wet or dry etching to form a protective insulating film on the surface of the finger electrode. A method of manufacturing a charge generator for an electrostatic image forming apparatus. 5. The method of manufacturing a charge generator for an electrostatic image forming apparatus according to claim 1, wherein a finger electrode is formed on the solid dielectric film, and a protective insulating film is formed on the surface of the finger electrode. , A step of forming and processing an insulating film made of an organic material such as polyimide by screen printing on the entire surface, then a step of adhering a metal thin plate for a screen electrode on the upper part of the insulating film with an adhesive, and then on the metal thin plate Forming a screen electrode by forming a resist pattern by a photolithography method and selectively removing a thin metal plate in a region not covered by the resist pattern by anisotropic dry etching. A method of manufacturing a charge generator for an image forming apparatus. 6. The method of manufacturing a charge generator for an electrostatic image forming apparatus according to claim 1, wherein a finger electrode is formed on the solid dielectric film, and a protective insulating film is formed on the surface of the finger electrode. After forming a photosensitive polyimide film on the entire surface by spin coating and baking at around 150 ° C, the polyimide film is processed by development after exposure by photolithography method, and then baked at around 350 ° C again. A step of forming an insulating film, a step of laminating a thin metal plate for a screen electrode on the upper part of the insulating film with an adhesive, and then forming a resist pattern on the thin metal plate by a photolithography method, and covering with the resist pattern. Forming a screen electrode by selectively removing a thin metal plate in an unetched region by anisotropic dry etching. Method for manufacturing a charge generator for a device.