JPH09141913A - Electrode body for image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a contact point from being broken by virtue of thermal expansion and contraction between an electrode substrate and a circuit board in terms of an electrode body for an image forming apparatus which is so constituted that the electrode substrate and circuit board that controls a driving signal applied to a control electrode on the substrate are integrally combined with each other to connect the control electrode with a wiring pattern of the circuit board. SOLUTION: An electrode substrate 2 on which a control electrode 4 for controlling the passing of toner is provided and a circuit board 3 for controlling a driving signal applied to the control electrode 4 are combined with each other. The control electrode 4 and a wiring pattern of the circuit board 3 are connected with each other. Coefficients of thermal expansion of both of the base materials of the electrode substrate 2 and circuit board 3 are set approximately equal so that the connected section is not broken even when the electrode substrate 2 or circuit board 3 has the thermal expansion by virtue of heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode body for an image forming apparatus, which can be used in a copying machine, a printer, a facsimile, etc., and controls the passage of charged particles to obtain an image.

[0002]

2. Description of the Related Art Conventionally, as one of image forming apparatuses, a drive signal based on an image signal is applied to an aperture electrode body having a plurality of small charged particle passage portions (referred to as apertures) to prevent toner from passing through the aperture. An image forming apparatus which obtains an image on an image recording medium such as a printing paper by controlling and passing the toner is disclosed as disclosed in JP-A-6-155798.

In such an image forming apparatus, as shown in FIG. 4, a toner carrying roller 102 and an image recording medium 103 are opposed to each other with an aperture electrode body 101 interposed therebetween, and further, a rear surface of the image recording medium 103 is provided on the back surface. Electrode roller 104
Is provided. The aperture electrode body 101 has a plurality of apertures 106 having a small diameter formed in a line in the longitudinal direction of the aperture electrode body 101 on a flexible substrate (FPC) 105 made of a thin sheet-shaped polyimide material or the like. Control electrodes 107 made of copper foil are formed around 106 respectively. The aperture electrode body 101 is fixed to a toner case 111, and a control voltage according to an image signal is applied to a control electrode 107 from a control voltage application circuit 112 to control the flight of the toner 113 carried by the toner carrying roller 102. Image recording medium 103
The image is formed on top.

By the way, the aperture electrode body 1 as described above is used.
In 01, since it is necessary to form a large number of fine apertures 106, an opening is formed by performing excimer laser processing or the like on a thin and flexible substrate 105 made of a polyimide material or the like. As shown in FIG. 5, when the circuit element 115 such as an IC chip that controls the drive signal applied to the control electrode 107 is to be integrally arranged on the flexible substrate 105, a large number of controls are performed on the substrate 105. The wiring of the electrode 107 and the terminal of the circuit element 115 are electrically connected. If a wire bonding method is used for the electrical connection,
Although it is necessary to accurately position the substrate 105, accurate positioning is not easy because the substrate 105 is not rigid and is flexible, and as a result, the manufacturing cost is high.

In order to solve such a manufacturing problem, the present applicant separates a flexible control board having an aperture electrode and a circuit board on which a circuit element is arranged from each other. Proposed a structure in which both substrates are joined and integrated by using a rigid base material, and mutual wiring is electrically connected by a wire bonding method or the like (see, for example, Japanese Utility Model Laid-Open No. 4-128843). .

[0006]

However, the aperture electrode body formed by integrating two substrates as described above is
When it is used for a printer or the like, at least an A4 size length is required, which is relatively long. In such a long structure in which substrates of two different materials are joined and electrically connected, the connection part (contact point) is destroyed due to the difference in thermal expansion / contraction of the material due to the temperature change of the use environment. There is a risk of

The present invention has been made to solve the above-mentioned problems, and an electrode substrate and a circuit substrate for controlling a drive signal applied to a control electrode of the substrate are bonded to each other,
An electrode body for an image forming apparatus, which is an electrode body formed by connecting and integrating a control electrode and a wiring of a circuit board without causing contact destruction due to thermal expansion / contraction of the electrode board and the circuit board. The purpose is to provide.

[0008]

In order to achieve the above object, an electrode body for an image forming apparatus according to the invention of claim 1 has a plurality of charged particle passage portions and a plurality of charged particle passage portions corresponding to the plurality of charged particle passage portions. It has an electrode substrate on which control electrodes are formed and supplies charged charged particles to the charged particle passage to control the passage of the charged particles, and the charged particles that have passed through the charged particle passage form an image on an image recording medium such as printing paper. In the obtained electrode body for an image forming apparatus, a circuit board for controlling a drive signal applied to the control electrode is provided, the electrode board and the circuit board are joined together, and the control electrode and the wiring of the circuit board are connected to each other, and the electrode board and the circuit are connected. The thermal expansion coefficient of each base material of the substrate is substantially the same. In the above configuration, the electrode substrate provided with the control electrode for controlling the passage of the charged particles and the circuit substrate for controlling the drive signal applied to the control electrode are bonded, and the control electrode and the wiring of the circuit substrate are connected. Even if the electrode substrate and the circuit board are thermally expanded due to the heat generated by energization, the thermal expansion coefficients of the base materials of the electrode substrate and the circuit board are substantially equal to each other. Is prevented. Moreover, since a thin and flexible base material can be used for the electrode substrate on which the charged particle passage portion is formed and a relatively rigid base material can be used for the circuit board, a substrate for wiring or the like during manufacturing can be used. The material can be easily positioned and the manufacturing neck is eliminated.

In the image forming apparatus electrode body according to a second aspect of the present invention, in the structure according to the first aspect, the expansion and contraction of these base materials are absorbed in the vicinity of the joint between the electrode substrate and the circuit board. The absorption means is provided. In the above configuration, even if the electrode substrate and the circuit board are thermally expanded by heat generation and a slight difference in thermal expansion between the base materials of the electrode substrate and the circuit board occurs, the absorbing means absorbs the expansion and contraction of these base materials. Therefore, the above operation can be reliably obtained.

The image forming apparatus electrode body according to a third aspect of the present invention is the one according to the first or second aspect of the invention, in which a slit or a groove formed in the base material is used as the absorbing means. is there. In the above structure, even if a slight difference in thermal expansion between the base materials of the electrode substrate and the circuit board occurs, the slits or grooves formed in the base material absorb the expansion and contraction of these base materials, and the above-mentioned action is achieved. can get.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an image forming apparatus equipped with an electrode body according to the present embodiment, and FIG.
3 is a perspective view of an electrode body and a circuit board used in the device, FIG.
FIG. 4 is a plan view of a joint portion between an electrode body and a circuit board. First, the image forming apparatus shown in FIG. 1 will be described. The image forming apparatus includes a toner supply device 10 for forming a toner image on an image recording medium 20, and an aperture electrode body 1 as an electrode array for controlling a toner flow is provided at one end of the toner supply device 10. It is provided. A back electrode plate 22 is arranged so as to face the aperture electrode body 1 with a distance of about 1 mm from the aperture electrode body 1. The image recording medium 20 is inserted and conveyed in the direction of arrow C by the rotation of the conveying roller 19 in the direction of arrow D in the gap between the aperture electrode body 1 and the back electrode plate 22. Further, a fixing device 26 that fixes an image on the image recording medium 20 is arranged in the conveying direction of the image recording medium 20. The fixing device 26 uses a thermal fixing method including a pressure roller 26a having silicon rubber on the surface layer and a heat roller 26b having a halogen heater inside.

Next, details of each section of the image forming apparatus will be described. As shown in FIG. 1, the toner supply device 10 includes a toner case 11 serving as a frame that also serves as a housing. In the toner case 11, toner 16 as charged particles is stored, and the toner 16 is carried. Then, a toner carrying roller 14 as a cylindrical charged particle supply means for carrying to the aperture electrode body 1 is rotatably supported in the toner case 11 in the direction of arrow B. Further, in the vicinity of the toner carrying roller 14, a cylindrical supply roller 12 for supplying the toner 16 stored in the toner case 11 to the toner carrying roller 14 is provided, and the supply roller 12 and the toner carrying roller 14 are provided. Are arranged in parallel with each other and contact the generatrix of their cylindrical surfaces. Also, the toner case 11
Above the toner carrying roller 14, the amount of the toner 16 carried by the toner carrying roller 14 is adjusted to be uniform on the roller surface of the toner carrying roller 14, and the toner 16 is evenly charged. A toner layer regulating blade 18 for the above is provided.

Next, details of the aperture electrode body 1 will be described. As shown in FIGS. 2 and 3, the aperture electrode body 1 uses an insulating sheet 2 made of polyimide having a thickness of 25 μm as an electrode substrate, and the insulating sheet 2 has apertures 6 ( The aperture array is shown in Fig. 2 because it is minute.
Are shown in a chain line) are formed in a line in the longitudinal direction of the aperture electrode body 1. Further, around the aperture 6, a control electrode 4 made of a copper foil having a thickness of 8 μm (the control electrode is shown in broken lines as a group in FIG. 2 because it is fine) is formed for each aperture 6. Note that in FIG. 1, the aperture 6 is schematically drawn larger than it actually is.

Further, the aperture electrode body 1 is provided with a circuit board 5 on which an IC 3 for controlling a drive signal applied to the control electrode 4 is mounted, and the lower surface of one end of the insulating sheet 2 and one end of this circuit board 5 are provided. The upper surface is joined with an adhesive or the like, and the control electrode 4 and the wiring of the circuit board 5 are connected. Further, the materials are selected so that the thermal expansion coefficients of the base materials of the insulating sheet 2 and the circuit board 5 are substantially equal to each other, and the circuit board 5 has slits at appropriate positions for absorbing the thermal expansion / contraction of the base material. 5b is included. The insulating sheet 2 is
It can be made of thin and highly rigid material such as polyimide or other resin material or ceramic. in this way,
Select the material so that the coefficient of thermal expansion of each substrate is almost the same,
Alternatively, the slit 5b for absorbing the thermal expansion / contraction of the base material is provided so that the strain can be released even if the expansion difference between the insulating sheet 2 and the circuit board 5 is caused by the thermal expansion. This is to prevent the connection portion from being destroyed.

Further, as shown in FIG. 3, the wiring 4c of the control electrode 4 of the insulating sheet 2 and the wiring 5c of the circuit board 5 are connected by a wire bonding method, an anisotropic conductive film, or another method. You can In addition, as shown in FIG. 1, the insulating sheet 2 and the circuit board 5 of the aperture electrode body 1.
Is joined to an attaching member with an adhesive or the like, and is attached to the toner case 11 via this member.

Next, the positional relationship between the apertures 6 of the aperture electrode body 1 and the toner carrying rollers 14 will be described. The center lines of the respective apertures 6 and the toner carrying roller 14 are at the center of the peripheral surface of the toner carrying roller 14. It is arranged so as to pass through the central axis of the roller 14. According to this, each aperture 6
Are evenly arranged in the toner conveying direction with reference to the front end of the peripheral surface of the toner carrying roller 14, so that the distribution of the toner 16 passing through each aperture 6 can be made uniform throughout the aperture. it can. Further, since the wall surface of the aperture 6 and the flying direction of the toner 16 are parallel to each other, it is possible to stably fly the toner. Aperture electrode body 1
It itself is pressed against the toner carrying roller 14 so as to bend about the aperture 6 in the toner conveying direction by the same angle. As a result, the contact area between the aperture electrode body 1 and the toner carrying roller 14 can be increased, and the lower periphery of the aperture 6 can be pressed uniformly in the toner conveying direction, resulting in uneven toner density. This can be suppressed as much as possible.

Next, the control device for each electrode will be described. As shown in FIG. 1, a control voltage applying circuit 8 is connected between the control electrode 4 and the toner carrying roller 14.
The control voltage applying circuit 8 is configured to apply a voltage of -30V or + 30V to the control electrode 4 based on an image signal sent from an image signal receiving means (not shown). The image signal receiving means (not shown) is connected to an external computer, an image reading device, an image communication device, or the like. Further, a backside voltage applying circuit 24 is connected between the backside electrode plate 22 and the toner carrying roller 14, and the backside voltage applying circuit 24 can apply a voltage of +1 kV to the backside electrode roller 22. Has become.

Next, the operation of the image forming apparatus configured as described above will be described with reference to FIG. Supply roller 12
The toner 16 stored in the toner case 11 is conveyed toward the toner carrying roller 14 by the rotation in the direction of arrow A. The conveyed toner 16 is rubbed against the toner carrying roller 14 and is negatively charged and carried on the toner carrying roller 14. Toner carrying roller 14
The toner 16 carried on the toner carrying roller 14 is conveyed while being carried on the cylindrical roller surface of the toner carrying roller 16 as the toner carrying roller 14 rotates in the direction of arrow B, and is thinned by the toner layer regulating blade 18. At the same time, the charging is made uniform, and the toner carrying roller 14 is conveyed toward the aperture electrode body 1 by the rotation in the arrow B direction. The toner on the toner carrying roller 14 is the insulating sheet 2 of the aperture electrode body 1.
It is fed under the aperture 6 while being rubbed by the.

Next, the image forming operation will be described. The control voltage applying circuit 8 applies a voltage of +30 V to the control electrode 4 corresponding to the image portion in accordance with the image signal sent from the image signal receiving means (not shown). as a result,
Due to the potential difference between the control electrode 4 and the toner carrying roller 14, an electric force line from the control electrode 4 toward the toner carrying roller 14 is formed in the aperture 6 in the control electrode 4 to which the voltage is applied. As a result, the negatively charged toner receives an electrostatic force in the direction of higher potential, and the toner carrying roller 1
It passes through the aperture 6 from above and is drawn out to the control electrode 4 side. The toner 16 that has been pulled out corresponds to the backside voltage application circuit 2
4 flies toward the image recording medium 20 due to the electric field formed between the image recording medium 20 and the aperture electrode body 1 by the voltage of +1 kV applied to the back electrode plate 22, and then the image is transferred onto the image recording medium 20. Deposit to form pixels.

Since a voltage of -30 V is applied from the control voltage applying circuit 8 to the control electrode 4 corresponding to the non-image portion, an electric field is formed between the toner carrying roller 14 and the control electrode 4. No toner 16 on the toner carrying roller 14
Does not receive the electrostatic force, so that the toner does not pass through the aperture 6. Therefore, no pixel is formed on the portion of the image recording medium 20 facing the control electrode 4. In this way, one row of pixels is formed on the surface of the image recording medium 20 by the toner 16, and then the carrying means carries one pixel in the direction perpendicular to the six rows of apertures. By repeating the above image forming process, a toner image is formed on the entire surface of the image recording medium 20. After that, the formed toner image is conveyed to the fixing device 26 by the conveying device, and the fixing device 26
The image is fixed on the image recording medium 20.

According to the electrode body for an image forming apparatus of the above-mentioned embodiment, during the operation of the electrode body composed of the insulating sheet 2 and the circuit board 5 bonded together, the ambient atmosphere, the environmental temperature change, and the heat generation of the electrode body itself. Even if thermal expansion / contraction occurs due to
Since the thermal expansion coefficients of the insulating sheet 2 and the base materials of the circuit board 5 are substantially equal to each other, there is little difference in expansion and contraction between the base material and the base material. Even if it is a simple one, it is possible to prevent the connection portion of the wirings of both substrates from breaking the contact. Furthermore, the circuit board 3
Since the slit 5b for absorbing the thermal expansion / contraction of the base material is provided at an appropriate position, even if there is a difference in the expansion due to the thermal expansion of both substrates, the strain can be released and the contact destruction. Is prevented. In addition, since a thin flexible base material can be used for the insulating sheet 2 which is the electrode substrate on which the aperture 6 through which the toner passes and a relatively rigid base material can be used for the circuit board 5, in terms of manufacturing. The base material for wiring and the like can be easily positioned, and work such as wiring can be easily performed.

The present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible. For example, in the above embodiment, the thermal expansion coefficients of the base materials of both substrates are made substantially equal, and
Although the slits are provided, even if the thermal expansion coefficients of the base materials of both substrates are made substantially equal to each other, there is little difference in elongation due to thermal expansion, and there is an effect of preventing contact breakage. Although the slits are provided on the circuit board 5 in the above description, the slits may be provided on the insulating sheet 2 side, or instead of the slits, the base material may be partially divided. Further, as the image forming apparatus, particles other than toner,
For example, an image may be formed using microcapsules containing a dye inside. Furthermore, in the above description, an image is formed by controlling the passage of toner through the aperture, but, for example, JP-A-6-255163 is used.
Instead of the aperture electrode, the control electrode may be formed only on one side with respect to the toner flow, as disclosed in Japanese Patent Laid-Open Publication No. 2003-242242.

[0023]

As described above, according to the electrode body for an image forming apparatus of the first aspect of the present invention, the electrode substrate provided with the control electrode and the circuit substrate for controlling the drive signal applied to the control electrode are provided. Are bonded to each other, and the coefficient of thermal expansion of each of the base materials of the electrode substrate and the circuit board is substantially equal, so even if the electrode substrate or the circuit board thermally expands, the connection part between the control electrode and the wiring of the circuit board will be destroyed. This is prevented. Further, according to the electrode body for an image forming apparatus of the second or third aspect of the invention, even if a slight difference in thermal expansion between the base material of the electrode substrate and the base material of the circuit board occurs, the absorbing means is provided with these base materials. Since the expansion and contraction are absorbed, the above-mentioned effects can be reliably obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an image forming apparatus equipped with an electrode body according to an embodiment of the present invention.

FIG. 2 is a perspective view of an electrode body and a circuit board used in the device.

FIG. 3 is a plan view of a wire connection portion of an electrode body used in the device.

FIG. 4 is a schematic sectional view of a conventional image forming apparatus.

FIG. 5 is a plan view of a conventional aperture electrode body.

[Explanation of symbols]

 1 Aperture electrode body 2 Insulating sheet (electrode substrate) 4 Control electrode 5 Circuit board 5b Slit 6 Aperture 10 Toner supply device 16 Toner 20 Image recording medium

Claims (3)

[Claims] 1. A plurality of charged particle passage portions and an electrode substrate on which a plurality of control electrodes are formed corresponding to the respective charged particle passage portions, and the charged particle passage portion is supplied with charged charged particles. In the electrode body for an image forming apparatus, which controls the passage of the charged particles and obtains an image on an image recording medium such as printing paper by the passed charged particles, a circuit board for controlling a drive signal applied to the control electrode. The invention is characterized in that the electrode substrate and the circuit board are joined and the control electrode and the wiring of the circuit board are connected to each other, and the thermal expansion coefficients of the respective base materials of the electrode substrate and the circuit board are substantially equal to each other. An electrode assembly for an image forming apparatus. 2. An electrode body for an image forming apparatus according to claim 1, wherein an absorbing means for absorbing expansion and contraction of these base materials is provided in the vicinity of a joint between the electrode substrate and the circuit board. . 3. The electrode body for an image forming apparatus according to claim 1, wherein the absorbing means is a slit or a groove formed in the base material.