JPH09123517A - Charge generator for electrostatic image forming apparatus and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to remove discharge product without using a supply fan and to realize the microminiaturization by providing a screen electrode having a hole for discharging charge via an air gap and a vent hole on the surface of the insulating film on a finger electrode, formed on a dielectric film on the surface of a line electrode. SOLUTION: An air gap 217 is formed at the lower layer of a screen electrode 214 in the charge generator for the electrostatic image forming apparatus. When the entire finger electrode 207 is exposed, corona discharge is generated at the entire finger electrode surface. To prevent it, a silicon oxide film 209 is formed on the surface of the electrode 207. Fine vent holes 216 are formed in a mesh state on the region where a plurality of charge generation control elements are disposed, and the air gap 217 is provided between the electrode 214 and the film 209 in the region A. On the other then A and, a polyimide film 211 is formed at the lower layer of the electrode 214 at the part except the region A.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a charge generator using a corona discharge has been used as a method of forming a latent image by electrostatic charge on a dielectric recording medium based on a principle of transferring and depositing electric charges directly on a dielectric recording medium. The method used is Japanese Patent Publication No. 2-6286.
No. 2 discloses such a charge generator,
The method of forming high definition using semiconductor fine processing technology,
Japanese Patent Application No. 6-268145, Japanese Patent Application No. 6-228475, Japanese Patent Application No. 6-288580, which are related to the applicant's application.
It is proposed in Japanese Patent Application No. 7-119018.

FIG. 18 is a partially cutaway perspective view showing an example of the construction of a charge generator for such an electrostatic image forming apparatus. Figure
In FIG. 18, reference numeral 500 denotes one charge generation control element, and the charge generator is configured by arranging a large number of charge generation control elements 500 one-dimensionally or two-dimensionally. The charge generation control element 500 includes an insulating substrate 501, a line electrode 502 made of metal, a dielectric film 503, a finger electrode 504 made of metal, an insulating film 505, and a screen electrode 506. Finger holes 507 and screen holes 508 are formed in the screen electrode 506, and a channel 509 is formed in the insulating film 505.
Are formed.

The charge generation control element 500 having the above structure
Each of the electrodes 502, 504, and 506 that compose the film 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 by photoetching, and then etching the portion not covered by the resist pattern. It is formed by removing by. Dielectric film 503
PCVD (Plasma-assisted Chemical Vapor Depos
a material having a high electrostatic withstand voltage such as silicon oxide or silicon nitride formed by a method such as ition). A resin having high heat resistance such as polyimide is used for the insulating film 505. The channel 509 formed in the insulating film 505 is
It is formed by selectively removing the insulating film 505 at a desired portion by an etching method.

Next, the operation of the charge generation control element 500 thus constructed will be described. In FIG.
By applying an AC voltage between the line electrode 502 and the finger electrode 504 which are arranged with the dielectric film 503 sandwiched between them, a charge group is generated on the side wall portion of the finger hole 507 and in the vicinity thereof due to a corona discharge phenomenon. Negative charges having a large mobility in the group of charges are used for forming a latent image. When a positive potential higher than the potential applied to the finger electrode 504 is applied to the screen electrode 506 formed facing the finger electrode 504 with the insulating film 505 interposed, the negative charge generated by the corona discharge is applied to the screen electrode 506. It is extracted from the formed screen hole 508. The negative charge extracted from the screen hole 508 is accelerated toward a drum (not shown) which is a dielectric recording body, and is deposited on the drum to form an electrostatic latent image. On the contrary, when a negative potential is applied to the screen electrode 506 with respect to the finger electrode 504, the extraction of the negative charge from the screen hole 508 is blocked and a latent image is not formed on the drum.

In such a type of charge generation control element, various discharge products generated by corona discharge are deposited on the surfaces of the finger electrodes 504 and the dielectric film 503, so that the characteristics change with time. However, regarding the removal of these discharge products, Japanese Patent Laid-Open No. 3-234556 discloses a charge generation control element having a structure as shown in FIG. The basic configuration of this charge generation control element is the same as that shown in FIG. 18 (the same components are denoted by reference numerals in the 600s).
However, a ventilation hole 610 is formed in the insulating film 605, and an air flow is made to flow through the ventilation hole 610 by a blower fan (not shown) so that the discharge product is discharged to the outside.

[0007]

By the way, as shown in FIG. 19, by providing a mechanism for discharging discharge products to the outside, it is possible to reduce the change in characteristics over time which has been a problem in the past. However, in that case, since it is necessary to install a blower fan for sending the air flow to the ventilation hole 610, the number of parts is increased. Furthermore,
Since it is very difficult to form the minute ventilation holes 610 in the insulating film 605 having a thickness of several 10 μm, an increase in manufacturing cost is inevitable. When the element is miniaturized to improve the resolution of the printed image, the side wall 611 of the insulating film 605 has finger holes.
There is a concern that the vent hole 610 may be exposed to the electric discharge and blocked if the air hole 610 is approached. However, Figure 19
The prior art shown in (1) does not consider those viewpoints, that is, the measures for increasing the number of parts, increasing the manufacturing cost, and damaging the ventilation hole due to the miniaturization of the element.

The present invention solves the above problems of the conventional charge generator for an electrostatic image forming apparatus, and suppresses an increase in manufacturing cost, while at the same time, provides a discharge product discharge mechanism capable of responding to miniaturization of elements. The present invention has been made in order to provide a charge generator for an electrostatic image forming apparatus and a method of manufacturing the same, and the invention according to claims 1 and 2 does not require external parts such as a blower fan and miniaturizes the element. It is an object of the present invention to provide a charge generator for an electrostatic image forming apparatus having a discharge product discharge function that can also be applied to the above. It is another object of the present invention to provide a structure capable of preventing crosstalk between adjacent elements, which is a problem when the dimensions of the elements are miniaturized in the charge generator according to claim 2. To do. Further, the invention according to claims 4 and 5 does not require external parts such as a blower fan, and the number of charge generators for an electrostatic image forming apparatus having a discharge product discharge function capable of coping with miniaturization of elements is small. It is an object of the present invention to provide a manufacturing method for forming in the number of steps.

[0009]

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, a dielectric film formed on the surface of the line electrode, A finger electrode formed on the surface of the dielectric film and having a hole for charge generation in the center, an insulating film having a hole formed on the surface of the finger electrode for allowing charges to pass through, and the insulating film Charge generation for an electrostatic image forming apparatus using a charge generation control element consisting of a screen electrode formed on the surface through an air gap and having a hole for discharging charges in the center and a ventilation hole for removing discharge products According to a second aspect of the present invention, in the charge generator for an electrostatic image forming apparatus according to the first aspect, a plurality of charge generation control elements having the above configuration are arranged on the same plane. Charge generation for electrostatic image forming devices It constitutes a.

As described above, by providing the screen electrode having the hole portion for discharging charges and the ventilation hole through the air gap on the surface of the insulating film formed on the finger electrode,
Since the atmosphere in the air gap is easily replaced with the outside air by heat convection, it is possible to remove the discharge products without using a blower fan, etc. It is possible to realize a charge generator for an electrostatic image forming apparatus that is also suitable for the above.

According to a third aspect of the invention, in the charge generator for an electrostatic image forming apparatus according to the second aspect, an insulating partition is provided in the air gap between the adjacent charge generation control elements. This makes it possible to prevent crosstalk between adjacent elements, which is a problem when the size of the charge generation control element is reduced.

According to a fourth aspect of the invention, a step of forming a finger electrode having a hole for charge generation on the surface of the insulating substrate on which the line electrode is formed via a dielectric film, and a first step on the surface of the finger electrode. A step of forming an insulating film and the first step
Removing a portion of the insulating film near the hole for charge generation of the finger electrode, and forming a second insulating film made of a material different from that of the first insulating film on the surface of the first insulating film. Forming a conductive film on the surface of the second insulating film, and forming a hole for discharging a charge and a vent for removing a discharge product on the surface of the conductive film to form a screen electrode. Forming an air gap between the first insulating film and the screen electrode by removing the second insulating film by isotropic etching using the screen electrode as a mask; A charge generator for a forming device is manufactured, and the invention according to claim 5 is a step of forming a finger electrode having a hole for charge generation through a dielectric film on the surface of an insulating substrate on which a line electrode is formed. And the finger A step of forming a first insulating film on the surface of the electrode, a step of patterning a second insulating film on the surface of the first insulating film by a screen printing method in a portion other than an area where an air gap is to be formed, and 2 is a step of adhering a conductive film to the surface of the insulating film, and a step of forming a screen electrode by forming holes for discharging charges and ventilation holes for removing discharge products on the surface of the conductive film. A charge generator for a forming apparatus is manufactured.

By these manufacturing methods, external parts such as a blower fan are not required, and a charge generator for an electrostatic image forming apparatus having a discharge product discharge function capable of coping with miniaturization of elements can be manufactured in a small number of steps. It can be easily manufactured in number.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Next, an embodiment of the present invention will be described. FIG. 1 is a plan view of a first embodiment of a charge generator for an electrostatic image forming apparatus according to the present invention as seen from a screen electrode side, and FIG. FIG. As shown in FIG. 2, the basic structure is the same as that of the conventional example, but the polyimide film under the screen electrode 214 is entirely removed to form an air gap 217. In the conventional example, since the finger electrodes are covered with a polyimide film, corona discharge does not occur in the portions other than the finger holes, but in the charge generator of the present invention, the entire finger electrodes are exposed, so the finger electrodes are not exposed. Corona discharge occurs on the entire surface. For this reason, the quality of the electrostatic image may be impaired by the leakage of charges to the adjacent dots or air holes, but in order to prevent such a phenomenon, a silicon oxide film 209 is formed on the surface of the finger electrode 207. ing. In a region indicated by A in FIG. 1 (a region where a plurality of charge generation control elements are arranged), a minute vent hole 216 is formed in the screen electrode 214.
Are formed in a mesh shape, and further, in this region A, an air gap 217 is formed between the screen electrode 214 and the silicon oxide film 209. On the other hand, in portions other than the region A, a polyimide film 211 is formed below the screen electrode 214 and supports the screen electrode 214.

Next, the first embodiment and the manufacturing method thereof will be described in more detail along the manufacturing process. 3 to 10 are views showing a sectional structure of the charge generation control element for the electrostatic image forming apparatus according to the first embodiment of the present invention in the order of manufacturing steps. First, as shown in FIG. 3, a resist pattern 20 is formed on the surface of a quartz (or glass) substrate 201 on which a titanium film is formed by a method such as sputtering, vacuum deposition, or plating.
After forming 2 by photo-etching method, resist pattern
Wet etching or RIE (Reactive-ion Etching) of the part of titanium film not covered by 202 with hydrofluoric nitric acid
The line electrode 203 is removed by a method such as
To form Next, after removing the resist pattern 202,
As shown in FIG. 4, a silicon oxide film 204 is formed as a dielectric film on the surface of the quartz (glass) substrate 201 on which the line electrode 203 is formed by a method such as sputtering or PCVD. Further, a titanium film 205 is formed on the surface by a method such as sputtering, vacuum deposition, plating or the like. Next, as shown in FIG. 5, a resist pattern 206 is formed on the surface of the titanium film 205 by a photo-etching method, and then the titanium film 205 in a portion not covered by the resist pattern 206 is wet-etched by fluorinated nitric acid or RIE. Then, the finger electrode 207 having the finger hole 208 is formed by removing the finger electrode 207.

Next, after removing the resist pattern 206,
As shown in FIG. 6, a silicon oxide film 209 is formed as a first insulating film on the surface of the finger electrode 207 by sputtering or P.
It is formed by a technique such as CVD. Next, as shown in FIG. 7, a resist pattern 210 is formed on the surface of the silicon oxide film 209.
After forming by photolithography, finger holes 20
The silicon oxide film 209 near 8 is removed by a method such as Wet etching with ammonium fluoride or RIE. Next, after removing the resist pattern 210, a polyimide film 211 is formed as a second insulating film on these surfaces, as shown in FIG. Further, a titanium film 212 is formed on the surface by a technique such as sputtering, vacuum deposition, plating or the like. Next, as shown in FIG. 9, a resist pattern 213 is formed on the surface of the titanium film 212 by a photo-etching method, and then the titanium film of a portion not covered with the resist pattern 213 is formed.
By removing 212 by wet etching using hydrofluoric nitric acid or a method such as RIE, the screen hole 215
And a screen electrode 214 having a vent hole 216 is formed.
Next, as shown in FIG. 10, by removing the polyimide film 211 in the charge generation control element formation region by isotropic etching, the charge generation control element shown in FIG. 10 is completed. At this time, the side etching proceeds not only from the screen hole 215 but also from the ventilation hole 216, so that the polyimide film 21 formed between the silicon oxide film 209 and the screen electrode 214 is etched.
All 1's are removed and an air gap 217 is formed.

In this embodiment, titanium is used for the line electrodes, finger electrodes and screen electrodes, but conductive materials such as aluminum, molybdenum, tungsten, titanium nitride, copper, gold, platinum and silver are used. film,
Alternatively, other materials such as a composite film composed of those conductive films can be used. However, since the surface of the finger electrode 207 is exposed to corona discharge, it is desirable to use a refractory metal. Further, although the example in which the dielectric film is composed of the silicon oxide film 204 is shown, other materials such as alumina and silicon nitride can be used as long as they have a high electrostatic withstand voltage. Further, an SOG (Spin On Glass) layer may be formed in the dielectric film in order to flatten the surface of the base of the finger electrode 207. Furthermore, magnesium oxide, zinc oxide, zirconium oxide, on the surface of the silicon oxide film 204 constituting the dielectric film,
A material having excellent durability against corona discharge such as alumina or titanium oxide may be formed as the protective film. Further, the example in which the first insulating film is composed of the silicon oxide film 209 is shown, but other materials such as alumina and silicon nitride can be used as long as they have a high electrostatic withstand voltage. Further, although the one using the polyimide film 211 as the second insulating film is shown, it is possible to form it with a film thickness of several tens of μm or more.
In addition, other materials such as resist can be used as long as the material can be finely processed on the order of several μm.

Further, regarding the vent holes 216, an example in which minute holes are formed in a mesh shape in the entire area A as shown in FIG. 1 is shown. However, as shown in FIG. 11, a portion apart from the screen hole 215 by several tens of μm. However, it is also possible to form the vent holes 216 in a mesh shape. In this case the air gap 21
In order to form 7 efficiently, the size (r in FIG. 11) of the portion where the vent hole 216 is not formed is preferably equal to or smaller than the film thickness of the polyimide film 211. Further, instead of forming the ventilation hole in a mesh shape, a ventilation hole 216 may be formed at a portion apart from the screen hole 215 by several tens of μm as shown in FIG.
Also in this case, the distance between the vent hole 216 and the finger hole 215 (r 'in FIG. 11) is preferably equal to or less than the film thickness of the polyimide film 211.

In this embodiment, the atmosphere in the air gap 217 is changed by the rotation of the drum and the air gap 21.
The heat convection of the air existing inside 7 easily replaces the outside air, so that the discharge products can be removed without using a blower fan or the like. Moreover, since the structure is very simple, it is suitable for miniaturization of elements. Further, since only the step of forming the silicon oxide film 209 is added to the conventional manufacturing process, the manufacturing cost is not significantly increased.

(Second Embodiment) FIG. 13 is a plan view of a charge generator for an electrostatic image forming apparatus according to a second embodiment as seen from the screen electrode side, and FIG. 14 is a plan view of FIG. It is an expanded perspective view which fractures | ruptures and shows the part shown by (beta). The basic configuration of this embodiment is the same as that of the first embodiment,
Same finger electrode (finger electrode commonly formed in charge generation control elements arranged in the same column direction)
The polyimide barrier ribs 305 are formed on the finger holes (eg, F1 and F2 in FIG. 14) formed in the adjacent holes 302.
Is different from that of the first embodiment. In FIGS. 13 and 14, 301 and 303 are silicon oxide films, 306 is a screen electrode, 307 is a screen hole, and 308 is a vent hole.

Next, a method of forming the partition wall 305 will be described. 3 to FIG.
9 is exactly the same as the first embodiment shown in FIG.
In forming the screen hole 215 and the vent hole 216 in the screen electrode 214 in the first embodiment, the vent hole 216 is formed over the entire surface of the screen electrode (excluding the screen electrode support portion) in the first embodiment. In the embodiment, in order to form the partition wall 305, the ventilation hole 308 is arranged in a portion other than the region where the partition wall 305 is to be formed, as shown in FIG. Next, as shown in FIG. 10, the polyimide film corresponding to the polyimide film 211 is removed by isotropic etching to form an air gap corresponding to the air gap 217. At this time, by side etching, the polyimide film is removed over the area distant from each screen hole 307 and the vent hole 308 by the distance indicated by s in FIG. 14, but the polyimide film is not etched in other areas. , The partition wall 305 is left. Here, if the etching time of the polyimide film is too long, the side wall 305 is gradually thinned by the side etching and eventually disappears. Therefore, the etching time must be adjusted so that the etching of the polyimide film is completed when the air gap is formed in the portion other than the region where the partition wall 305 is to be formed.

Also in this embodiment, the materials mentioned in the first embodiment can be used as the electrodes, the dielectric film, the first insulating film, and the second insulating film. Further, an SOG layer may be formed in the silicon oxide film 301 serving as a dielectric film in order to flatten the base of the finger electrodes. Furthermore,
A material having excellent durability against corona discharge, such as magnesium oxide, zinc oxide, zirconium oxide, alumina, or titanium oxide, may be formed on the surface of the silicon oxide film 301 as a protective film. In the present embodiment, the insulating partition walls are provided between the adjacent elements to prevent crosstalk between the adjacent elements, which is a concern when the discharge product removing mechanism as in the first embodiment is provided. Have the effect of

(Third Embodiment) FIGS. 15 to 17 are views showing a sectional structure of a charge generator for an electrostatic image forming apparatus according to a third embodiment in the order of manufacturing steps. First, as shown in FIG. 15, quartz (or glass) is used as in the first embodiment.
After a line electrode 402, a dielectric film 403, a finger electrode 404 having a finger hole 405, and a first insulating film 406 are sequentially formed on the surface of a substrate 401, a polyimide film 407 is patterned by a screen printing method as a second insulating film. Form. At this time, the polyimide film 407 is formed only in a portion other than the region (corresponding to the region A in FIG. 1) where the charge generation control element is arranged. A member denoted by reference numeral 408 in FIG. 15 is an alignment mark. The alignment mark 408 is used for aligning the resist pattern with the line electrode pattern 402 when a resist pattern is formed by a photolithography method in a later step. For use in
The description is omitted in the first and second embodiments.

Next, as shown in FIG. 16, a polyimide film 407 is formed.
A titanium thin film 409 is adhered to the surface of the. Next, as shown in FIG. 17, a resist pattern 410 is formed on the surface of the titanium thin film 409.
Are formed by a photo-etching method. At this time, since the alignment mark 408 is used for alignment of the resist pattern, the portion of the titanium thin film 409 located above the mark 408 must be removed in advance before bonding. Next, the titanium film in the portion not covered with the resist pattern 410 is removed by anisotropic etching such as RIE, so that the screen hole 412 and the vent hole 413 are formed.
By forming the screen electrode 411 provided with the above, a charge generator provided with the air gap 414 having the same structure as shown in FIG. 2 is completed.

Also in this embodiment, the materials mentioned in the first embodiment can be used as the electrodes, the dielectric film, the first insulating film, and the second insulating film. In addition, in order to flatten the base of the finger electrodes, S is added in the dielectric film 403.
An OG layer may be formed. Furthermore, a material having excellent durability against corona discharge such as magnesium oxide, zinc oxide, zirconium oxide, alumina and titanium oxide may be formed on the surface of the dielectric film 403 made of a silicon oxide film as a protective film. Further, regarding the shape of the vent holes 413, as in the first embodiment, in addition to the arrangement shown in FIG.
The arrangement shown in 12 is also applicable. Also in this embodiment, the same effect as that of the first embodiment can be obtained.

[0026]

As described above based on the embodiments, according to the inventions of claims 1 and 2, by providing an air gap and forming a vent hole for removing discharge products in the screen electrode. It is possible to realize a charge generator for an electrostatic image forming apparatus that does not require an external component such as a blower fan and has a discharge product discharge mechanism that is compatible with miniaturization of elements. According to the invention of claim 3, claim 2
In the charge generator described above, it is possible to prevent crosstalk between adjacent elements, which is a concern when the dimensions of the elements are miniaturized. Further, according to the inventions of claims 4 and 5, a charge generator for an electrostatic image forming apparatus, which does not require an external component such as a blower fan and has a discharge product discharge mechanism that can cope with miniaturization of elements. Can be easily manufactured with a small number of steps.

[Brief description of the drawings]

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

FIG. 2 is an enlarged perspective view showing a part of the first embodiment shown in FIG. 1 by breaking it.

FIG. 3 is a diagram showing a manufacturing process for explaining the manufacturing method of the first embodiment shown in FIGS. 1 and 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 that follows the manufacturing process shown in FIG. 6;

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 plan view showing a modification of the first embodiment shown in FIG. 1.

FIG. 12 is a plan view showing another modification of the first embodiment shown in FIG. 1.

FIG. 13 is a plan view showing a second embodiment of the present invention.

FIG. 14 is an enlarged perspective view showing a part of the second embodiment shown in FIG. 13 in a cutaway manner.

FIG. 15 is a diagram showing a manufacturing process for explaining the third 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 partially cutaway perspective view showing a configuration example of a conventional charge generator for an electrostatic image forming apparatus.

FIG. 19 is a cross-sectional view showing a configuration example of a conventional charge generator for an electrostatic image forming apparatus including a discharge product discharge mechanism.

[Explanation of symbols]

 201 Quartz (or glass) substrate 202,206,210,213 Resist pattern 203 Line electrode 204,209 Silicon oxide film 205,212 Titanium film 207 Finger electrode 208 Finger hole 211 Polyimide film 214 Screen electrode 215 Screen hole 216 Vent hole 217 Air gap 301,303 Silicon oxide film 302 Finger electrode 305 Partition wall 306 Screen electrode 307 Screen hole 308 Vent hole 401 Quartz (or glass) substrate 402 Line electrode 403 Dielectric film 404 Finger electrode 405 Finger hole 406 First insulating film 407 Polyimide film 408 Alignment mark 409 Titanium thin film 410 Resist pattern 411 Screen electrode 412 Screen hole 413 Vent hole 414 Air gap

Claims (5)

[Claims] 1. A line electrode formed on the surface of an insulating substrate, a dielectric film formed on the surface of the line electrode, and a hole portion for charge generation in the center portion formed on the surface of the dielectric film. A finger electrode, an insulating film formed on the surface of the finger electrode and having a hole for allowing charges to pass through in the center, and a hole for discharging charges in the center formed in the insulating film surface through an air gap A charge generator for an electrostatic image forming apparatus, which is configured by using a charge generation control element including a screen electrode having a ventilation hole for removing a discharge product. 2. The charge generator for an electrostatic image forming apparatus according to claim 1, wherein a plurality of the charge generation control elements are arranged on the same plane. 3. The charge generator for an electrostatic image forming apparatus according to claim 2, wherein an insulating partition is provided in an air gap between adjacent charge generation control elements. 4. A step of forming a finger electrode having a hole for charge generation on a surface of an insulating substrate on which a line electrode is formed through a dielectric film, and a step of forming a first insulating film on the surface of the finger electrode. A step of removing a portion of the first insulating film in the vicinity of the hole for charge generation of the finger electrode, and a step of forming a material different from the first insulating film on the surface of the first insulating film. Forming an insulating film, forming a conductive film on the surface of the second insulating film, and forming holes for discharging charges and vents for removing discharge products on the surface of the conductive film. And forming a screen electrode by using the screen electrode as a mask, and removing the second insulating film by isotropic etching to form an air gap between the first insulating film and the screen electrode. Specially to have A method of manufacturing a charge generator for an electrostatic image forming apparatus. 5. A step of forming a finger electrode having a hole for charge generation on a surface of an insulating substrate on which a line electrode is formed through a dielectric film, and a step of forming a first insulating film on the surface of the finger electrode. A step of patterning a second insulating film on the surface of the first insulating film by a screen printing method in a portion other than a region where an air gap is to be formed, and a step of adhering a conductive film to the surface of the second insulating film. A step of forming a screen electrode by forming a hole for discharging a charge and a vent hole for removing a discharge product on the surface of the conductive film. Production method.