JPH08230227A - Charge generating control element for electrostatic image forming apparatus - Google Patents

Abstract

PURPOSE: To prevent a lowering of durability accompanied by making an element fine by constituting a first finger electrode of a high m.p. metal and a second finger electrode of a material having heat conductivity higher than that of the first finger electrode. CONSTITUTION: A first finger electrode 106 is constituted of titanium having a high m.p. because heat is generated on the surface thereof by corona discharge. The second finger electrode 104 formed in a first insulator film 103 is constituted of aluminum high in heat conductivity and both electrodes are connected by the contact hole 105 bored in the first insulator film 103. Since the heat generated in the first finger electrode 106 is transmitted to the second finger electrode 104 to be rapidly discharged to the outside, the temp. rise in the vicinity of the hole part of the first finger electrode 103 is suppressed. As a result, the lowering of durability accompanied by making an element fine can be prevented.

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.

[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. 16 is a perspective view showing a part of the structure of a conventional charge generator for an electrostatic image forming apparatus in a cutaway manner. In FIG. 16, 500 indicates a single charge generation control element,
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 made of quartz or glass, a line electrode 502 made of metal, a first insulator film 503, a finger electrode 504 made of metal, and a second insulator film 505. , Screen electrode 506, and finger hole 507 and screen hole 508 are formed in finger electrode 504 and screen electrode 506, respectively.

The charge generation control element 500 having the above structure
Each of the electrodes constituting the above 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 a photo-etching method, and then removing the portion not covered by the resist pattern by etching. Is formed by. For the first insulator film 503, a material having a high electrostatic withstand voltage such as silicon oxide formed by a method such as plasma CVD (Plasma Chemical Vapor Deposition) or silicon nitride is used. Also the second
For the insulating film 505, a resin having high heat resistance such as polyimide is used.

Next, the operation of the charge generation control element 500 thus constructed will be described. In FIG.
Line electrodes 502 arranged with the first insulator film 503 sandwiched therebetween.
By applying an AC voltage between the finger electrode 504 and the finger electrode 504, a charge group is generated in the side wall portion of the finger hole 507 and in the vicinity thereof by a corona discharge phenomenon. Negative charges having high mobility in this charge group are used for latent image formation. The second insulator film 505 is provided so as to face the finger electrodes 504.
When a positive potential higher than the potential applied to the finger electrodes 504 is applied to the screen electrode 506 formed by interposing, the negative charge generated by the corona discharge is extracted from the screen hole 508 formed in the screen electrode 506. It The negative charges extracted from the screen holes 508 are accelerated toward a drum (not shown), which is a dielectric recording body, and are 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 the latent image is not formed on the drum.

[0006]

By the way, when the charge generation control element shown in FIG. 16 is driven, the heat generated by the corona discharge is released from the finger electrodes 504 to the outside by heat conduction. When the finger electrode 504 is thinned for the purpose of reducing the thickness, the thermal conductivity of the finger electrode 504 is lowered, so that the temperature in the vicinity of the finger hole 507 is significantly increased. Therefore, there is a problem in that the electrostatic withstand voltage of the first insulator film 503 formed under the finger electrode 504 is deteriorated due to the temperature rise, and the durability of the element is significantly lowered. . Although such a problem is ameliorated by using a material having a high thermal conductivity such as aluminum for the finger electrodes, such a material having a high thermal conductivity generally has a relatively low melting point, and the heat generation of corona discharge and I can't stand the shock of plasma.

The present invention has been made to solve the above problems of the conventional charge generation control element, and the invention of claim 1 improves the thermal conductivity of the finger electrodes while maintaining the high melting point characteristics. By doing so, it is an object of the present invention to provide a charge generation control element for an electrostatic image forming apparatus, which makes it possible to prevent deterioration of durability due to miniaturization of the element.
The second and third aspects of the present invention are intended to provide a practical element structure in the first aspect of the invention.

[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 first finger electrode formed on the first insulator film and having a hole for charge generation in the central portion, and the first finger electrode electrically and thermally A second finger electrode connected to the first finger electrode, and a second insulator film having a hole at the center for allowing charges to pass through are formed on the surface of the first finger electrode. In the charge generation control element including a screen electrode having a hole portion, the first finger electrode is made of a refractory metal, and the second finger electrode is made of a material higher than that of the refractory metal constituting the first finger electrode. Constructed of highly conductive material It is intended to.

As described above, since the first finger electrode formed of the high melting point metal is connected to the second finger electrode formed of the high thermal conductivity material, the thermal conductivity of the finger electrode is improved and the first finger electrode is improved. Since the heat generated in the hole portion of the finger electrode is quickly released to the outside through the first and second finger electrodes, the temperature increase in the vicinity of the hole portion of the first finger electrode is suppressed. Therefore, deterioration of the electrostatic withstand voltage of the first insulator film due to a temperature rise in the vicinity of the hole portion of the finger electrode, which is a problem when the element is miniaturized, is prevented, and the charge for the electrostatic image forming apparatus having high durability is prevented. A generation control element can be realized.

According to a second aspect of the invention, the second finger electrode of the charge generation control element according to the first aspect is formed inside the first insulator film. Thus, the first finger electrode and the second finger electrode are
When the first finger electrode is formed by etching by separating the second finger electrode by the insulating film, even if the material forming the second finger electrode is attacked, the second finger electrode can be made of the same material. Can be formed.

According to a third aspect of the present invention, the second finger electrode of the charge generation control element according to the first aspect is formed on the surface of the insulator substrate. This makes the second
Since it is possible to form the finger electrodes and the line electrodes at the same time, it is possible to significantly reduce the number of steps.

[0012]

EXAMPLES Next, examples will be described. FIG. 1 is a partially cutaway perspective view showing a first embodiment of a charge generation control element for an electrostatic image forming apparatus according to the present invention. In the figure, 101
Is a quartz (glass) substrate, and 102 is a line electrode made of aluminum. 103 is the first insulator film,
It is composed of silicon oxide having a thickness of several microns formed by plasma CVD. Reference numeral 106 denotes a first finger electrode, which is made of titanium having a high melting point because heat is generated by corona discharge on its surface. Reference numeral 104 denotes a second finger electrode formed in the first insulator film 103, which is made of aluminum having high thermal conductivity. The first finger electrode 106 and the second finger electrode 104 have Contact hole 105 opened in the insulator film 103 of
Are connected to each other. 107 is a second insulator film, which is made of a highly heat-resistant resin such as polyimide. Reference numeral 108 denotes a screen electrode, which is formed using a single-layer metal film of titanium, molybdenum, aluminum, titanium nitride, or the like, or a multi-layer metal film made of these materials. 109 and 110 are finger holes and screen holes, respectively.

Next, the manufacturing process of the charge generation control element of this embodiment will be described. 2 to 9 are views showing the cross-sectional structure of the element of this example in the order of manufacturing steps. First, as shown in FIG. 2, an aluminum film 202 and a titanium film 203 are sequentially formed on a quartz (glass) substrate 201 by a method such as sputtering or vacuum deposition, and then a resist pattern 204 is formed on the surface of the titanium film 203. Here, the titanium film 203 functions as a hillock prevention film for the aluminum film 202. Next, as shown in FIG. 3, a portion of the aluminum film 202 and the titanium film 203 which is not covered with the resist pattern 204 is removed by etching to form a line electrode 205. Next, as shown in FIG. 4, after removing the resist pattern 204, a silicon oxide film 206 is formed by a method such as plasma CVD. Further, an aluminum film 207 to be the second finger electrode is formed on the surface by a method such as sputtering or vacuum evaporation.

Next, as shown in FIG.
After forming the resist pattern 209 on the surface of 7, the second finger electrode 208 is formed by removing the aluminum film portion not covered by the resist pattern 209 by etching. Next, as shown in FIG. 6, after removing the resist pattern 209, the silicon oxide film 210 is removed.
To form. The silicon oxide films 206 and 210 form a first insulator film. Next, as shown in FIG. 7, after forming the resist pattern 211, the contact hole 212 is formed by removing the portion not covered with the resist pattern 211 by etching. Next, as shown in FIG. 8, after removing the resist pattern 211, a titanium film 213 to be the first finger electrodes is formed.
Are formed by a technique such as sputtering or vacuum deposition. Next, as shown in FIG. 9, after forming a resist pattern 214 on the surface of the titanium film 213, a portion not covered with the resist pattern 214 is removed by etching to form a first finger electrode 215. Then, a second insulating film and a screen electrode are sequentially formed on these upper layers to complete the charge generation control element as shown in FIG.

In FIG. 2, the aluminum film 202
Instead of forming the hillock-preventing titanium film 203 on the surface of, the silicon oxide film 206 shown in FIG. 4 may be partially or entirely formed at a temperature of 200 ° C. or lower. In addition, although aluminum is used as the electrode material of the line electrode in this embodiment, a single layer film of titanium, molybdenum, tungsten, copper, titanium nitride, or the like, or a composite film made of these materials is used. The above materials can also be used. In addition, although the one in which titanium is used as the aluminum hillock prevention film is shown, titanium nitride,
Other materials such as molybdenum and tungsten can also be used. Furthermore, although the one using silicon oxide as the first insulator film is shown, if it is a material having a high electrostatic withstand voltage,
Other materials such as a single layer film of silicon nitride or alumina or a composite film made of silicon oxide, silicon nitride, or alumina can be used. Furthermore, in order to flatten the underlayer of the finger electrodes, SOG (Spin On) is formed in the first insulator film.
A Glass) layer may be formed.

In the present embodiment, the heat conductivity of the finger electrodes is improved so that the heat generated by the corona discharge is rapidly released to the outside, so that the temperature rise near the finger holes is suppressed. This makes it possible to prevent the electrostatic breakdown voltage of the first insulator film from deteriorating due to the temperature rise in the vicinity of the finger holes, so that charge generation control for an electrostatic image forming apparatus becomes a problem when the element is miniaturized. The durability of the element is greatly improved.

Next, a second embodiment will be described. FIG. 10 is a perspective view showing the structure of the charge generation control element of the second embodiment. The basic structure is the same as that of the first embodiment, but the second finger electrode 304 is formed on the boundary between the quartz (glass) substrate 301 and the first insulator film 303, that is, on the quartz substrate 301. The points are different.

11 to 15 are views showing the sectional structure of the element of the second embodiment in the order of manufacturing steps, and the manufacturing method of the second embodiment will be described based on these manufacturing step drawings. First, Fig. 11
As shown in FIG. 1, after the aluminum film 402 and the titanium film 403 are sequentially formed on the quartz (glass) substrate 401 by a method such as sputtering or vacuum deposition, the line electrode 404 and the second finger are formed in the same manner as in the first embodiment. The electrode 405 is formed. Next, as shown in FIG. 12, a silicon oxide film 406 is formed by a technique such as plasma CVD. Next, as shown in FIG. 13, after forming a resist pattern 407 on the surface of the silicon oxide film 406, a portion not covered with the resist pattern 407 is removed by etching to form a contact hole 408.

Next, as shown in FIG. 14, a resist pattern
After removing 407, a titanium film 409 to be the first finger electrodes is formed by a method such as sputtering. Next, as shown in FIG. 15, after forming a resist pattern 410 on the surface of the titanium film 409, the resist pattern 410 is formed.
The first finger electrode 411 is formed by removing the portion not covered by the etching by etching. Then, by sequentially forming the second insulating film and the screen electrode on these layers, the charge generation control element as shown in FIG. 10 is completed.

Also in this embodiment, other materials as mentioned in the first embodiment can be used as the aluminum hillock prevention film, the line electrode and the first insulator film. Also, a titanium film for hillock prevention is formed on the surface of the aluminum film 402.
Instead of forming 403, part or all of the silicon oxide film 406 may be formed at a temperature of 200 ° C. or lower. Further, in order to flatten the base of the first finger electrode 411, an SOG layer may be formed in the silicon oxide film forming the first insulator film.

Also in this embodiment, the same effect as that of the first embodiment can be obtained. Further, since the second finger electrode and the line electrode can be formed at the same time, the number of steps can be reduced.

[0022]

As described above on the basis of the embodiments,
According to the first aspect of the present invention, it is possible to suppress the temperature rise in the vicinity of the hole of the finger electrode, so that the durability is superior to the conventional charge generation control element for an electrostatic image forming apparatus. And a charge generation control element for an electrostatic image forming apparatus. According to the invention of claim 2, the first
Even if the material forming the second finger electrode is attacked when the finger electrode is formed by etching, the second finger electrode can be formed with the material. Further, according to the invention of claim 3, the second finger electrodes and the line electrodes can be formed at the same time, so that the number of steps can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a first 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 manufacturing method of the first embodiment shown in FIG.

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 that follows the manufacturing process shown in FIG. 6;

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 perspective view showing a second embodiment of the present invention with a part thereof broken away.

FIG. 11 is a diagram showing a manufacturing process for explaining the manufacturing method of the second embodiment shown in FIG.

FIG. 12 is a diagram showing a manufacturing process that follows the manufacturing process shown in FIG. 11.

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.

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

FIG. 16 is a partially cutaway perspective view showing a configuration example of a charge generation control element for a conventional electrostatic image forming apparatus.

[Explanation of symbols]

 101 quartz (glass) substrate 102 line electrode 103 first insulator film 104 second finger electrode 105 contact hole 106 first finger electrode 107 second insulator film 108 screen electrode 109 finger hole 110 screen hole 201 quartz ( Glass) Substrate 202 Aluminum film 203 Titanium film 204 Resist pattern 205 Line electrode 206 Silicon oxide film 207 Aluminum film 208 Second finger electrode 209 Resist pattern 210 Silicon oxide film 211 Resist pattern 212 Contact hole 213 Titanium film 214 Resist pattern 215 1st Finger electrode 301 Quartz (glass) substrate 302 Line electrode 303 First insulator film 304 Second finger electrode 305 Contact hole 306 First finger electrode 307 Second insulator film 308 Screen electrode 309 Finger hole 310 Screen hole 401 Quartz (glass) substrate 402 Aluminum Nium film 403 titanium film 404 line electrode 405 second finger electrode 406 silicon oxide film 407 resist pattern 408 contact hole 409 titanium film 410 resist pattern 411 first finger electrode 500 charge generation control element 501 insulating substrate 502 line electrode 503 first Insulator film 504 Finger electrode 505 Second insulator film 506 Screen electrode 507 Finger hole 508 Screen hole

Claims (3)

[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 first finger electrode having holes for charge generation;
Second electrically and thermally connected to the finger electrodes of the
And a screen having a hole for discharging electric charges in the central portion formed on the surface of the first finger electrode through a second insulator film having a hole for allowing electric charges to pass through in the central portion. In the charge generation control element including electrodes, the first finger electrode is made of a refractory metal, and the second finger electrode is made of a material having a higher thermal conductivity than that of the refractory metal constituting the first finger electrode. A charge generation control element for an electrostatic image forming apparatus, which is configured by: 2. The second finger electrode is the first finger electrode.
The charge generation control element for an electrostatic image forming apparatus according to claim 1, wherein the charge generation control element is formed inside the insulating film. 3. The second finger electrode is formed on the surface of the insulator substrate.
A charge generation control element for an electrostatic image forming apparatus according to claim 1.