JPH09123516A - Charge generation control element for electrostatic imaging forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress aging of characteristics by providing a protective film having high durability against corona discharge on the surface of a dielectric film. SOLUTION: Silicon oxide 103 and silicon nitride 104 are deposited, as a dielectric film, on the surface of a quartz substrate 101 on which a line electrode 102 is formed followed by deposition of titanium. A resist pattern is then formed on the surface and etching is performed to leave the titanium in the vicinity of a region for making a finger hole. Subsequently, the titanium is thermally oxidized to produce titanium oxide 107 for protective film and titanium is deposited thereon. A resist pattern is then formed thereon and etching is performed to form a finger electrode 110 of titanium. Finally, a polyimide 111 is deposited and a screen electrode 112 is formed along with a channel 113 thus completing a charge generation control element.

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. The method of using is 2-6
Japanese Patent Application No. 6-268, filed by the applicant of the present application, discloses a method of forming such a charge generation control element with high precision using a semiconductor fine processing technique.
No. 145, Japanese Patent Application No. 6-282475, Japanese Patent Application No. 6-28
No. 8580, Japanese Patent Application No. 7-119018 and the like.

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 above, reference numeral 300 denotes one charge generation control element, and the charge generator is configured by arranging a large number of charge generation control elements 300 in one dimension or two dimensions. The charge generation control element 300 includes an insulating substrate 301, a line electrode 302 made of metal, a dielectric film 303, a finger electrode 304 made of metal, an insulating film 305, and a screen electrode 306. Finger holes 307 and screen holes 308 are formed in the screen electrode 306, and the channel 30 is formed in the insulating film 305.
9 is formed.

Then, the charge generation control element 300 having the above structure
Each of the electrodes 302, 304, and 306 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 303
PCVD (Plasma-assisted Chemical Vapor Dep
), a material having a high electrostatic withstand voltage such as silicon oxide or silicon nitride is used. The insulating film 305 is made of a resin having high heat resistance such as polyimide. The channel 309 formed in the insulating film 305 is formed by etching the insulating film 30 at a desired position.
It is formed by selectively removing 5.

Next, the operation of the charge generation control element 300 thus constructed will be described. In FIG.
By applying an AC voltage between the line electrode 302 and the finger electrode 304 arranged with the dielectric film 303 interposed therebetween, a charge group is generated by the corona discharge phenomenon in the side wall portion of the finger hole 307 and in the vicinity thereof. 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 304 is applied to the screen electrode 306 formed facing the finger electrode 304 with the insulating film 305 interposed, negative charges generated by corona discharge are applied to the screen electrode 306. It is extracted from the formed screen hole 308. The negative charges extracted from the screen hole 308 are accelerated toward a drum (not shown) which is a dielectric recording body and deposited on the drum to form an electrostatic latent image. On the contrary, when a negative potential with respect to the finger electrode 304 is applied to the screen electrode 306, extraction of negative charges from the screen hole 308 is blocked, and a latent image on the drum is not formed.

[0006]

By the way, in the conventional charge generation control element, as shown in FIG. 13, since the dielectric film 303 is exposed inside the finger hole 307, the surface of the dielectric film 303 is exposed to corona discharge. It is gradually scraped by the impact. Therefore, there has been a problem that the characteristics of the element change with time due to the electric potential distribution near the finger holes changing every moment. The problem is that the dielectric film 303
This can be solved by forming a substance having high durability against corona discharge on the surface of as a protective material. However, since these substances are generally chemically stable, etching processing is often difficult.

The present invention has been made to solve the above problems of the conventional charge generation control element, and the invention according to claim 1 is provided with a protective film having high durability against corona discharge on the surface of the dielectric film. Another object of the present invention is to provide a method of manufacturing a charge generation control element for an electrostatic image forming apparatus, which has a small change over time, and the invention according to claims 2 and 3 forms a protective film on the surface of a dielectric film by thermal oxidation. In this case, it is an object of the present invention to provide a method of manufacturing a charge generation control element for an electrostatic image forming apparatus, which is capable of preventing oxidation of a line electrode that has already been formed. A fourth aspect of the invention is to provide a charge generation control element for an electrostatic image forming apparatus having a simple structure and high durability against corona discharge, and the fifth aspect of the invention is to reduce the number of steps. It is an object of the present invention to provide a method of manufacturing a charge generation control element for an electrostatic image forming apparatus, which simultaneously forms a finger electrode and a protective insulator.

[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, a dielectric film formed on the surface of the line electrode, A protective film formed on the surface of the dielectric film, a finger electrode formed on the surface of the protective film and having a hole portion for charge generation in the center, and a hole for allowing the charge to pass through to the center of the finger electrode surface. In a method of manufacturing a charge generation control element for an electrostatic image forming apparatus, which comprises a screen electrode having a hole for discharging charges in a central portion formed through an insulating film having a portion, the protective film is formed in advance. It also includes a step of forming by thermally oxidizing a metal film of titanium, magnesium, zinc, zirconium or the like.
By forming the protective film with a thermal oxide film of a metal film in this way, a charge generating device for an electrostatic image forming apparatus, which has a protective film with high durability against corona discharge and which can suppress changes in characteristics over time, is provided. The control element can be easily manufactured.

According to a second aspect of the present invention, in the method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to the first aspect, part or all of the dielectric film is an insulator film having a high oxygen shielding effect. According to a third aspect of the present invention, in the method of manufacturing the charge generation control element for an electrostatic image forming apparatus according to the second aspect, the insulator film having a high oxygen blocking effect is formed of silicon nitride. Is. This prevents oxidation of the already formed line electrode,
A protective film can be formed on the surface of the dielectric film by thermal oxidation.

According to a fourth aspect of the present invention, a line electrode formed on the surface of the insulating substrate, a dielectric film formed on the surface of the line electrode, and a dielectric film formed on the surface of the dielectric film for charge generation in the central portion. A finger electrode having a hole portion, and a screen electrode having a hole portion for discharging a charge in the center portion, which is formed on the surface of the finger electrode through an insulating film having a hole portion for allowing a charge to pass therethrough. In the charge generation control element for an electrostatic image forming apparatus, alumina, titanium oxide, magnesium oxide, in the holes formed in the finger electrodes,
It is constructed by embedding a protective insulator such as zinc oxide or zirconium oxide, which has high durability against corona discharge. This makes it possible to realize a charge generation control element for an electrostatic image forming apparatus, which has a protective insulator having a high durability against corona discharge with a simple configuration.

According to a fifth aspect of the present invention, in the method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to the fourth aspect, titanium, magnesium, zinc,
A step of forming a metal film of zirconium or the like, and a portion of the metal film where the hole portion of the finger electrode is formed is selectively oxidized to a boundary portion with the dielectric film using a film having a high oxygen shielding effect as a mask. Then, a step of simultaneously forming a protective insulator having high durability against corona discharge and a finger electrode is provided. This makes it possible to simultaneously form the finger electrodes and the protective insulator in one thermal oxidation step.

[0012]

Next, an embodiment of the present invention will be described. 1 to 8 are views showing a sectional structure for explaining a first embodiment of a charge generation control element and a manufacturing method thereof according to the present invention in the order of manufacturing steps. First, as shown in FIG. 1, a silicon oxide film 10 as a dielectric film is formed on the surface of a quartz (or glass) substrate 101 on which a line electrode 102 is formed.
3 and silicon nitride film 104 by sputtering or PCVD
After the titanium film 105 is sequentially formed by such a method as described above, the titanium film 105 is formed by a method such as sputtering, vacuum deposition, and plating.
Next, as shown in FIG. 2, after forming a resist pattern 106 on the surface of the titanium film 105, the titanium film 105 in a portion not covered by the resist pattern 106 is removed by etching to form a finger hole formation region. The titanium film 105 is left in the vicinity. Next, as shown in FIG.
After removing the resist pattern 106, the titanium film 105 is thermally oxidized to form a titanium oxide 107. At this time, when oxygen atoms diffuse into the dielectric film and reach the line electrode 102, there is a problem that the line electrode 102 is oxidized and electric resistance increases, but a silicon nitride film 104 is previously formed as an oxygen shielding film. By doing so, oxidation of the line electrode 102 is prevented. Note that a silicon oxide film
If 103 is sufficiently thicker than the diffusion length of oxygen determined by the temperature and time required for converting titanium film 105 into titanium oxide, silicon nitride film 104 may not be formed.

Next, as shown in FIG. 4, a titanium film 108 is formed on the surfaces of the titanium oxide 107 and the silicon nitride film 104. Next, as shown in FIG. 5, after forming a resist pattern 109 on the surface of the titanium film 108, the resist pattern 109 is formed.
The finger electrode 110 is formed by etching away the portion not covered by. Next, FIG.
After removing the resist pattern 109, the polyimide film 111, the screen electrode 112, and the channel 113 in the polyimide film are formed to complete the charge generation control element as shown in FIG.

In this embodiment, the dielectric film is composed of the silicon oxide film 103 and the silicon nitride film 104 formed on the surface thereof. As shown in FIG. 2, the structure in which the silicon nitride film 115 is sandwiched between the silicon oxide films 114 and 116, and the silicon nitride film 11
A structure in which a silicon oxide film 118 is formed on the surface of 7 may be adopted. If a low-stress silicon nitride film can be formed, the entire dielectric film may be composed of a silicon nitride film. If the insulator has a high oxygen shielding effect, a silicon nitride film
Instead of 104, other materials such as carbon nitride, alumina film, etc. may be used. Further, if the material has a high electrostatic withstand voltage, other material such as polyimide can be used instead of the silicon oxide film 103. Furthermore, in order to flatten the surface of the finger electrode base, SOG (Spin On
A Glass) layer may be formed.

Further, as the protective film of the dielectric film, the one using titanium oxide 107 obtained by thermally oxidizing the titanium film is shown, but if the material has excellent durability against corona discharge, magnesium is used. A thermal oxide film of a metal such as zinc, zirconium or zirconium can also be used. Further, in the steps shown in FIGS. 4 and 5, the surface resistance of the titanium oxide 107 for a protective film may be reduced by forming the finger electrode 110 made of a titanium film on the surface of the titanium oxide 107 which is a protective film. . In this case, the problem can be solved by forming a silicon oxide film, a silicon nitride film, or the like so as to be interposed between the titanium oxide 107 for protective film and the finger electrode 110. In the present embodiment, by forming a protective film having high durability against corona discharge on the surface of the dielectric film, it is possible to suppress the change over time of the charge generation control element for the electrostatic image forming apparatus.

FIGS. 9 to 12 are sectional views showing a charge generation control element for an electrostatic image forming apparatus and a manufacturing method thereof according to a second embodiment of the present invention in the order of manufacturing steps. Is. First, as shown in FIG. 9, a silicon oxide film 203 and a silicon nitride film 204 as dielectric films are formed on the surface of a quartz (or glass) substrate 201 on which a line electrode 202 is formed.
After sequentially forming by a method such as sputtering or PCVD, a titanium film 205 is formed by a method such as sputtering, vacuum deposition, plating, etc., and a silicon nitride film 206 is formed on the surface of the titanium film 205. Next, as shown in FIG. 10, after forming a resist pattern 207 on the surface of the silicon nitride film 206, a portion of the silicon nitride film that is not covered by the resist pattern 207 is removed by etching to form a finger electrode formation region. Silicon nitride film 206
Leave.

Next, as shown in FIG. 11, a resist pattern
After removing 207, the titanium film 205 is thermally oxidized. Here, only the portion not covered with the silicon nitride film 206 is selectively oxidized to form titanium oxide 209, and the other portions become finger electrodes 208 made of a titanium film.
Next, as shown in FIG. 12, after removing the silicon nitride film 206, a polyimide film 210, a screen electrode 211 and a channel 212 are formed to complete the charge generation control element.

Also in this embodiment, as the dielectric film (silicon oxide film 203 and silicon nitride film 204) and the protective film (titanium oxide 209) for the dielectric film, other than those mentioned in the first embodiment. The above materials can also be used. Further, an SOG layer may be formed in the dielectric film for flattening the base of the finger electrodes. Further, as long as the silicon nitride film 206 used as a mask for selective oxidation is a material having a high oxygen shielding effect, other materials can be used regardless of whether or not it has conductivity, but a conductive material such as titanium nitride can be used. When using a flexible material,
The removal process after the selective oxidation becomes unnecessary.

Also in the present embodiment, the same effect as that of the first embodiment can be obtained. Further, since the titanium oxide to be the protective film and the finger electrodes can be formed at once, there is an effect that the number of steps can be reduced.

[0020]

As described in detail above, according to the invention described in claim 1, an electrostatic image having a protective film having high durability against corona discharge and capable of suppressing change in characteristics with time is provided. The charge generation control element for the forming apparatus can be easily manufactured. According to the inventions of claims 2 and 3,
A protective film by thermal oxidation can be formed on the surface of the dielectric film while preventing the oxidation of the already formed line electrode. According to the invention described in claim 4, it is possible to realize a charge generation control element for an electrostatic image forming apparatus, which has a simple structure and is provided with a protective insulator having high durability against corona discharge. According to the invention of claim 5, the finger electrodes and the protective insulator can be simultaneously formed in one thermal oxidation step.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing process for explaining a first embodiment of a charge generation control element for an electrostatic image forming apparatus and a manufacturing method thereof according to the present invention.

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

FIG. 3 is a 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 corresponding to FIG. 1 showing a modified example of the first embodiment.

FIG. 8 is a diagram corresponding to FIG. 1 showing another modification of the first embodiment.

FIG. 9 is a diagram showing a manufacturing process for explaining the second embodiment of the charge generation control element for the electrostatic image forming apparatus and the manufacturing method thereof according to the present invention.

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 that follows the manufacturing process shown in FIG. 11.

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

[Explanation of symbols]

 101,201 Quartz (or glass) substrate 102,202 Line electrode 103,114,116,118,203 Silicon oxide film 104,115,117,204,206 Silicon nitride film 105,108,205 Titanium film 106,109,207 Resist pattern 107,209 Titanium oxide 110,208 Finger electrode 111,210 Polyimide film 112,211 Screen electrode 113,212 Channel

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, a protective film formed on the surface of the dielectric film, and a protective film formed on the surface of the protective film. A hole for discharging electric charges in the central portion formed through an insulating film having a finger electrode having a hole portion for generating electric charges in the central portion and a hole portion for allowing electric charges to pass through in the central portion on the surface of the finger electrode. In a method of manufacturing a charge generation control element for an electrostatic image forming apparatus, which comprises a screen electrode having a section,
A method of manufacturing a charge generation control element for an electrostatic image forming apparatus, comprising the step of forming the protective film by thermally oxidizing a metal film of titanium, magnesium, zinc, zirconium or the like formed in advance. 2. The method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to claim 1, wherein a part or all of the dielectric film is made of an insulating film having a high oxygen shielding effect. 3. The method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to claim 2, wherein silicon nitride is used as the insulator film having a high oxygen shielding effect. 4. A line electrode formed on the surface of an insulating substrate, a dielectric film formed on the surface of the line electrode, and a finger formed on the surface of the dielectric film and having a hole for charge generation in the center thereof. For an electrostatic image forming device comprising an electrode and a screen electrode formed on the surface of the finger electrode through an insulating film having a hole for allowing charges to pass through at the center, and having a hole for discharging charges at the center. In the charge generation control device, a protective insulator having high durability against corona discharge such as alumina, titanium oxide, magnesium oxide, zinc oxide, zirconium oxide is embedded in the hole formed in the finger electrode. A charge generation control element for an electrostatic image forming apparatus. 5. The method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to claim 4, wherein a step of forming a metal film of titanium, magnesium, zinc, zirconium or the like on the surface of the dielectric film, and the metal A portion of the film where the hole of the finger electrode is formed is selectively oxidized to a boundary with the dielectric film by using a film having a high oxygen shielding effect as a mask, and a protective insulator having high durability against corona discharge. A method of manufacturing a charge generation control element for an electrostatic image forming apparatus, comprising the step of simultaneously forming finger electrodes.