JP2004201445A - High voltage generator and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high voltage generator in which a noise that occurs between a plurality of high voltage cables is reduced. <P>SOLUTION: In the high voltage generator, a high voltage from a high voltage generating part is supplied to a plurality of loads through a plurality of high voltage cables. To prevent electrical interference between the plurality of high voltage cables, an insulating high-voltage cable holding member 1 is provided where through holes 1a are opened to hold the plurality of high voltage cables with constant interval. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high voltage generator and an image forming apparatus such as a copying machine or a laser beam printer provided with the high voltage generator.
[0002]
[Prior art]
An image forming apparatus such as a copying machine or a laser beam printer, as shown in FIG. 7, has a charging device 52 for uniformly charging the outer peripheral surface of a photosensitive drum 51 serving as an image carrier, and a modulation device based on image information. An exposure device 53 that irradiates the photosensitive drum 51 with a laser beam or the like; a developing device 54 that forms a toner image by attaching toner or the like as a developer to the electrostatic latent image formed on the photosensitive drum 51; A transfer device 56 for transferring the toner image formed on the photosensitive drum 1 to a transfer sheet as a transfer material conveyed from a paper feed cassette 55 is provided. The transfer paper on which the toner image has been transferred by the transfer device 6 is conveyed to the fixing device 7, where the visible image on the transfer paper is fixed by heating and pressing, and is discharged to the paper discharge tray 8.
[0003]
In the course of this image formation, a bias by a high voltage of several KV is required to cause the developer to fly from the developing device 7 to the photosensitive drum 1 and be adsorbed. In order to fly the agent, a bias with a higher voltage is required. When the high voltage generator is separated from the location requiring the bias, the voltage is supplied via a high voltage cable. However, when there are a plurality of high-voltage cables, when the distance between the cables is small or they intersect, electric interference may occur, and bias may be deviated, thereby lowering image reproducibility.
[0004]
Therefore, for example, Patent Document 1 discloses that a high-voltage cable is fixed to a board base that fixes a board to an apparatus main body, so that a distance between the board and the high-voltage cable is secured even in a space, and a stable image is obtained even when the high-voltage cable becomes long. It has been proposed to provide a bias to suppress noise generation in signal lines involved in device operation. This prior art also proposes reducing electrical noise by applying a conductive thin film on the entire substrate stand.
[0005]
[Patent Document 1]
JP-A-7-325443
[Problems to be solved by the invention]
However, in the above-mentioned prior art, a board stand or the like must be provided as a condition for reducing the mutual interference of the high-voltage cables, so that there are certain restrictions on the way of installation. Also, electrical noise is reduced by attaching a conductive thin film to the entire substrate base, but such a thin film shows that stray capacitance peculiar to high voltage is not considered. .
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances of the related art, and an object of the present invention is to provide a high-voltage generator that reduces noise generation between high-voltage cables and an image forming apparatus including the generator. It is in.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a first means is a high voltage generator that supplies a high voltage from a high voltage generator to a plurality of loads via a plurality of high voltage cables, wherein the plurality of high voltage cables are held at equal intervals. Insulating high voltage cable holding means for suppressing the occurrence of electrical interference between the high voltage cables is provided between the plurality of high voltage cables.
[0009]
The second means is the first means, wherein the high-voltage cable holding means is formed of a flat plate-like member, and the high-voltage cable insertion through hole penetrating from one end to the other end is provided from the one end of the member to the other end. It is characterized by being formed at an interval in a direction perpendicular to the end.
[0010]
A third means is the first means, wherein the high-voltage cable holding means is formed of a columnar member, and the high-voltage cable insertion through hole penetrating from one end to the other end in the axial direction is provided at an outer peripheral portion of the member. It is characterized by being formed in the vicinity at intervals in the circumferential direction.
[0011]
A fourth means is the first means, wherein the high-voltage cable holding means is formed of a columnar member, and a groove capable of inserting and holding the high-voltage cable is formed on an outer peripheral surface from one end to the other end in the axial direction. It is characterized by being formed at intervals in the circumferential direction.
[0012]
According to a fifth aspect, in the first to fourth aspects, the high-voltage cable holding means is made of an insulating synthetic resin.
[0013]
Sixth means is a high voltage generator for supplying a high voltage from a high voltage generator to a plurality of loads via a plurality of high voltage cables, wherein the high voltage generation cycle variable means for changing the frequency of the high voltage; Selecting means for setting a frequency of the voltage, wherein the selecting means transmits a high voltage having a different frequency for each load to the high-voltage cable.
[0014]
A seventh means is the sixth means, wherein the high-voltage cable is held by high-voltage cable holding means according to the first to fifth means.
[0015]
Eighth means for developing and developing the electrostatic latent image formed on the image carrier, and supplying a high voltage to the image carrier for transferring the visualized image to a transfer material. In the image forming apparatus provided with a plurality of high voltage cables, the high voltage cables are held by high voltage cable holding means in the first to fifth means.
[0016]
The ninth means develops the electrostatic latent image formed on the image carrier into a visible image, and transfers a high voltage from a high voltage generator to a plurality of high voltage In the image forming apparatus for supplying the image carrier with a cave, the high-voltage generating device is configured by a sixth or seventh unit.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a perspective view showing a high-voltage cable holding member according to the first embodiment, FIG. 2 is a front view showing a high-voltage cable holding member according to the second embodiment, and FIG. 3 is a high-voltage cable according to the third embodiment. It is a front view which shows a holding member.
[0019]
In FIG. 1, a high-voltage cable holding member 1 is configured to hold a part of a high-voltage cable (not shown) in a planar shape at equal intervals. That is, the high-voltage cable holding member 1 in the form of a flat plate is made of an insulating material made of a hard resin such as plastic, and a plurality of through holes 1a for passing the high-voltage cable from one end to the other end are formed at equal intervals. ing. The number of through holes 1a is determined according to the number of high-voltage cables used. In the first to third embodiments described here, six high-voltage cables are used. These are mounted at equal intervals (for example, at intervals of 20 cm) at the time of turning from a high-voltage power supply (not shown) to the photosensitive drum 51 as a photosensitive member. Thereby, the plurality of high-voltage cables are held at predetermined intervals, and mutual interference between the high-voltage cables can be reduced.
[0020]
In the above-described first embodiment, the shape of the high-voltage cable holding member 1 tends to spread laterally as the number of high-voltage cables increases, and the installation location is restricted as the number of high-voltage cables increases. I will. In order to solve this drawback, in the second embodiment shown in FIG. 2, the high-voltage cable holding member is formed in a cylindrical shape. That is, the high-voltage cable holding member 2 has a columnar shape with a circular cross section, and the through-holes 2a through which the high-voltage cable is inserted are provided at equal intervals near the outer peripheral portion.
[0021]
The second embodiment is suitable for a case where a plurality of high-voltage power supply outputs are connected to respective loads, such as a color image forming apparatus. That is, when a plurality of high-voltage power supply outputs such as a charging output and a development output are connected to respective loads (loads on an image forming process, for example, a tandem type photosensitive drum) when a high-voltage cable of a color image forming apparatus is turned on, A high-voltage cable on the high-voltage power supply side has a strong tendency to bundle all outputs (for example, K: black / C: cyan / M: magenta / Y: yellow). In the second embodiment, since the high-voltage cable holding member 2 has a columnar shape, a plurality of high-voltage cables can be held in a form following this tendency.
[0022]
As shown in FIG. 4, the high-voltage cable is configured so that the core wire 4 is coated with a double coating composed of a first coating 5 and a second coating 6, and is made of a conductive material and an insulating material. It can be said that there is. If a housing frame (not shown) is made of a conductive material such as steel in this state, an insulating material is interposed between the core wire 4 and the housing frame, which may be equivalent to a capacitor. In this state, a stray capacitance peculiar to high voltage is generated, which may cause noise. To alleviate this, the high voltage cables can be turned around at a constant distance at equal intervals regardless of the length of the high voltage cables.
[0023]
In the above-described first and second embodiments, the high-voltage cable holding member 1 or the high-voltage cable holding member 1 is connected before the high-voltage power supply side, such as between the high-voltage generator and the photosensitive drum, is connected to the additional side. Although a high-voltage cable must be inserted through the through-holes 1a or 2a of the second cable, it may be configured to be attachable to the high-voltage cable even after being connected between the high-voltage power supply side and the additional side. This example is shown in FIG. 4 as a third embodiment. That is, the high-voltage cable holding member 3 according to the third embodiment is a developed form of the second embodiment, and is inserted by pushing the high-voltage cable into the outer periphery of a columnar member having a circular cross section. Possible holding grooves 3a are provided at predetermined intervals. Generally, it is good to provide at equal intervals. Since the holding portion of the high-voltage cable is groove-shaped in this manner, the high-voltage cables are fitted together after a fixed distance from the high-voltage power supply side to the load side as a mounting procedure. Can be turned. In the above-described first embodiment, a groove whose upper part (one surface side) is open may be used instead of the through hole.
[0024]
A case where a plurality of high-voltage cables are held by the above-described high-voltage cable holding member will be described with reference to FIG.
[0025]
FIG. 5 is a diagram illustrating a state where a plurality of high-voltage cables are held by a plurality of high-voltage cable holding members. That is, the high-voltage cable holding members 8 of the present invention are attached to the plurality of high-voltage cables 9 at equal intervals. Since the high-voltage cable holding members 8 have the structure described in the second or third embodiment described above, the plurality of high-voltage cables 9 have a rounded shape and do not take up space. By attaching the high-voltage cable holding members 8 at equal intervals, a constant distance can be maintained between the high-voltage cables 9.
[0026]
Next, a fourth embodiment shown in FIG. 6 will be described.
[0027]
FIG. 6 is a block diagram showing the fourth embodiment. That is, in the fourth embodiment, noise is electrically reduced. That is, in the fourth embodiment, a control board unit (in the present embodiment, only a control signal unit of a high-voltage power supply is described) 10 which includes a CPU 11 and controls the entire system of the image forming apparatus, and a selection unit 14 , A high-voltage power supply unit 12 on which a driving unit 15 and a high-voltage output unit 13 are mounted. The driving unit 15 is a high-voltage generation cycle variable circuit, and includes three driving units, a first driving unit, a second driving unit, and a third driving unit, each having a different output frequency.
[0028]
The selection unit 14 is configured by, for example, a demultiplexer, and selects one of various data according to one input data. The signal to be handled is a digital signal composed of binary values of a high level and a low level. For example, when the signal is defined as valid (high active) at the H level using an NPN transistor in the preceding stage of the driving unit, the signal is processed in the subsequent stage of the driving unit. A certain drive circuit (for example, an oscillation circuit and an amplifier circuit using an operational amplifier) is driven, and the voltage is output after being transformed by a high-voltage output unit 13 composed of, for example, a transformer. Details of how to switch the selection unit 14, that is, the demultiplexer in these series of flows will be described.
[0029]
For example, it is assumed that the output frequency of the charging output circuit is 1 kHz when an output circuit such as a development output circuit and a charging output circuit is driven. On the other hand, if the frequency of the development output is 2 kHz when the development output circuit is driven, the relationship between the charging output and the frequency of the development output becomes an integral multiple. Thus, when the frequency is an integral multiple, mutual interference occurs, and the waveform on the low frequency side is affected by the high frequency component. In the above case, the charging output circuit is on the low frequency side, and the high frequency component of the development output circuit affects the charging output circuit. In order to avoid this, the high-voltage power supply unit 12 of FIG. 6 is provided on the development output circuit side, the frequency of the first drive unit is 1.2 kHz in this embodiment, the frequency of the second drive unit is 2.2 kHz, and the third The frequency of the drive unit is set to 3.2 kHz. Then, for example, in the development output circuit, the selection unit 14 is set so that the third drive unit is enabled. The operation of the demultiplexer is omitted because it is an existing technology. Note that the variable range of the development output frequency differs depending on each specification, and it is necessary to ensure a wide range since accuracy is required. Therefore, in the fourth embodiment, the variable range is 1.2, 2.2. Although the description has been made assuming that the frequency can be changed at three kinds of frequencies of 3.2 kHz, it is sufficient that a frequency that does not become an integral multiple can be selected.
[0030]
【The invention's effect】
As described above, according to the present invention, noise generated between high-voltage cables can be reduced with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a high-voltage cable holding member according to a first embodiment of the present invention.
FIG. 2 is a front view showing a high-voltage cable holding member according to a second embodiment of the present invention.
FIG. 3 is a front view showing a high-voltage cable holding member according to a third embodiment of the present invention.
FIG. 4 is a diagram illustrating an example of the structure of a high-voltage cable.
FIG. 5 is a diagram showing a state where a plurality of high-voltage cables are held by a plurality of high-voltage cable holding members.
FIG. 6 is a block diagram showing a fourth embodiment of the present invention.
FIG. 7 is a diagram illustrating a schematic configuration of a conventional image forming apparatus.
[Explanation of symbols]
1, 2, 3, 8 High voltage cable holding members 1a, 2a Through hole 3a Holding groove 9 High voltage cable 10 Control board unit 11 CPU
12 High voltage power supply unit 13 High voltage output unit 14 Selection unit 15 Drive unit 15a First drive circuit 15b Second drive circuit 15c Third drive circuit

Claims (9)

In a high voltage generator that supplies a high voltage from a high voltage generator to a plurality of loads through a plurality of high voltage cables,
Insulating high-voltage cable holding means for holding the plurality of high-voltage cables at equal intervals and suppressing occurrence of electrical interference between the high-voltage cables is provided between the plurality of high-voltage cables. Voltage generator. The high-voltage cable holding means is formed of a plate-shaped member, and the high-voltage cable insertion through holes penetrating from one end to the other end thereof are spaced from each other in a direction orthogonal to the one end to the other end of the member. The high voltage generator according to claim 1, wherein the high voltage generator is formed. The high-voltage cable holding means is formed of a columnar member, and the high-voltage cable insertion through holes penetrating from one end to the other end in the axial direction are formed at intervals in the circumferential direction near the outer peripheral portion of the member. 2. The high voltage generator according to claim 1, wherein: The high-voltage cable holding means is formed of a columnar member, and grooves for inserting and holding the high-voltage cable are formed on the outer peripheral surface from one end to the other end in the axial direction at circumferential intervals. The high-voltage generator according to claim 1, wherein: The high-voltage generator according to any one of claims 1 to 4, wherein the high-voltage cable holding means is made of an insulating synthetic resin. In a high voltage generator that supplies a high voltage from a high voltage generator to a plurality of loads through a plurality of high voltage cables,
High voltage generation cycle variable means for varying the frequency of the high voltage,
Selecting means for setting the frequency of the high voltage,
A high-voltage generator that transmits a high voltage having a different frequency for each load to the high-voltage cable by the selection unit. The high-voltage generator according to claim 6, wherein the high-voltage cable is held by the high-voltage cable holding unit according to claim 1. A plurality of high-voltage cables for developing and developing the electrostatic latent image formed on the image carrier and supplying a high voltage to the image carrier for transferring the visualized image to a transfer material In the image forming apparatus provided with
An image forming apparatus, wherein the high-voltage cable is held by the high-voltage cable holding unit according to claim 1. The electrostatic latent image formed on the image carrier is developed and visualized, and a high voltage from a high voltage generator is applied to the image carrier by a plurality of high voltage cables to transfer the visualized image to a transfer material. In the image forming apparatus to be supplied to
An image forming apparatus comprising: the high voltage generator according to claim 6.

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