JPH07285235A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image forming device which is free from the occurrence of a color shear and forms a high-quality image by forming recording units consisting of a carrier which carries and supplies electrically charged particles and an electric field control means which directly controls the flow of the electrically charged particles by the electric field, into an integrally formed single body. CONSTITUTION:An image forming device consists of recording units each being composed of a carrier 23 which carries and supplies electrically charged particles and an electric field control means which is arranged separately from the carrier 23 through the electrically charged particles and directly controls the flow of the particles by an electric field. In this case, the recording units are formed in a single piece. That is, the shafts of toner-carrying rollers 23 are correctly positioned using an integral formation member 37. Consequently, no positional misalignment occurs, if various colors are lapped over the other and printing data at a controlled position is possible. Thus, it is possible to obtain a output of high-quality image free from a color shear.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus which can be used in copying machines, printers, plotters, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, as one of image forming apparatuses, an electrode having a plurality of openings (hereinafter referred to as apertures) is used, and a voltage is applied to the electrode based on image data. U.S. Pat. No. 3,689,935 discloses controlling toner particles so that they can pass through the aperture and forming an image on a support by the toner particles that have passed.

This image forming apparatus comprises a flat plate made of an insulating material, a continuous reference electrode formed on one surface of the flat plate, and a plurality of control electrodes insulated from each other formed on the other surface. , An aperture electrode body having at least one row of apertures formed through each of the control electrodes, and a means for selectively applying a potential between the reference electrode and the control electrode. A means for supplying the charged toner particles so that the flow of the toner particles passing through the aperture is modulated by the electric potential, and a means for relatively moving the support and the aperture electrode body to position the support in the particle flow path. It consists of and.

Also, for example, US Pat. No. 4,743,926.
Nos. 4,755,837, 4,780,733, and 4,847,796 disclose an image forming apparatus in which an aperture electrode body is arranged with a control electrode on the support side and a reference electrode on the toner supply side. There is.

In contrast, US Pat. No. 4,912,489
In the specification of the above U.S. Pat. It is described that it can be suppressed to about 1/4 as compared with the image forming apparatus.

Here, the "off" means a time when the toner particles are not attached to the support, that is, a time when a blank portion of an image is formed, and conversely, "on" means that the support is on the support. It means a time point when a toner image is formed on.

Such a printing method can form a simple printing unit which is high speed, high resolution and compatible with plain paper.
Further, since excellent gradation can be obtained, it has excellent characteristics as an image forming apparatus for color output.

[0008]

However, in the conventional image forming apparatus as described above, a plurality of recording units including the aperture electrode body are individually mounted in the apparatus, and the positional deviation of the dots of each color occurs. It was a big problem. That is, since the positions of the dots formed by the respective apertures are slightly different from each other, there is a problem that the colors appear blurred even on the output.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus having excellent image quality in which color misregistration does not occur.

[0010]

In order to achieve this object, an image forming apparatus of the present invention comprises a carrier for supporting and supplying charged particles, the carrier is arranged via charged particles, and is charged by an electric field. An image forming apparatus having a plurality of recording units configured with an electric field control means for directly controlling the flow of particles, wherein the plurality of recording units are integrally formed.

[0011]

In the image forming apparatus of the present invention having the above-mentioned structure, it is possible to print at a controlled position without causing a positional shift when the respective colors are overlapped. As a result, it is possible to perform output that is excellent in image quality without color shift.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an image recording apparatus to which the present invention is applied. The image recording apparatus 10 is roughly composed of a process unit 20, a fixing unit 40, and a paper transport unit 5.
0, the counter electrode 60, and the power supply unit 70. In this apparatus, after a full-color toner image is formed on the sheet 51 as an image receiving body in the process unit 20, heat fixing is performed in the fixing unit 40 and then discharged to the outside of the apparatus. On the left side of the exterior 11 of the image recording apparatus, there are a discharge port 12 for the paper 51 and a tray 1.
3 is provided.

A process unit 2 installed in the center of the machine
0 has the following configuration. That is, the process unit 20 includes a recording unit 21 and a toner supply unit 22, and the recording unit 21
Is a mechanism for recording the toner 16 of each color of yellow, magenta, cyan, and black, and is configured integrally. The recording unit will now be described in more detail with reference to FIGS. 2 and 3. The recording unit 21 includes a body 38 integrally formed of synthetic resin or the like that also serves as a housing of the entire apparatus, toner 16 as charged particles stored in the body 38, four supply rollers 24, and a carrier. Four toner carrying rollers 23 and a toner layer regulating blade 2 arranged corresponding to each toner carrying roller 23
5 and an aperture electrode body 30 as an electric field control means, which is arranged at the bottom of the body 38. Here, the toner carrying roller 23 carries the toner 16 and conveys it toward the aperture electrode body 30, and the supply roller 24 supplies the toner 16 to the toner carrying roller 23.

The supply roller 24 and the toner carrying roller 23 are rotatably supported by the body 38 in the direction of the arrow shown in the figure, and they are arranged in parallel while being in contact with each other. Further, the toner layer regulating blade 25 is for adjusting the amount of the toner 16 carried by the toner carrying roller 23 to be uniform on the toner carrying roller 23 and for uniformly charging the toner 16. , Are pressed against the toner carrying roller 23.

Further, a shaft 36, which is a rotating shaft formed at both ends of the toner carrying roller 23, is positioned by a bearing 36 arranged in an integral member 37 as a supporting member provided outside the body 38. There is. The integrated member is a so-called high-precision frame component, and it is possible to accurately determine the position between the shafts. The integrated member 37 is provided on each side of the body 38. It is arranged.

The toner supply unit 22 is filled with the above-described four color toners 16 separately, and is installed when the user supplies toner. Toner supply unit 2
2 may be formed separately for each color or may be integrated. The toner 16 is preferably a so-called small particle size toner having a particle size of about 7 μm in terms of image quality, and both pulverized toner and polymerized toner can be used. When installed on this machine, toner 16
Are released to the recording unit 21.

Now, the aperture electrode body 30 of the recording unit 21 will be described in detail. The aperture electrode body 30 is
It is composed of four recording electrodes 34 provided corresponding to each color. Here, one of the four recording electrodes 34 will be described with reference to FIG. As shown in FIG. 4, the recording electrode 34 includes a 25 μm thick insulating sheet 31 made of polyimide, and a plurality of apertures 32 each having a diameter of 100 μm as a toner flow control section formed in a line and controlled above each aperture 32. Electrode 33 is 1μ
It is formed with a thickness of m. The recording electrode 34 is fixed to the bottom of the body 38 so that the control electrode 33 faces the sheet 51 side and the insulating sheet 31 contacts the toner 16 on the toner carrying roller 23 at the aperture position.

In this embodiment, four recording electrodes 3 are used.
Although each of the insulating sheets 31 of 4 is integrally formed of one sheet, it may be formed separately for each recording electrode 34 and fixed to the bottom of the body 38 for each recording electrode 34. Four
When the insulating sheets 31 of the individual recording electrodes 34 are integrated and configured as one sheet, color misregistration due to a positioning error can be eliminated and better image quality can be obtained than when configured separately. .

A control voltage application circuit 26 as a control voltage application means is connected between the control electrode 33 and the toner carrying roller 23. This control voltage application circuit 2
6 is 0 V with respect to the control electrode 32 based on the image signal,
Alternatively, it is configured to apply a voltage of + 40V.

Aperture electrode body 3 of process unit 20
A counter electrode 60 is provided so as to sandwich 0 and the paper 51. The counter electrode 60 is composed of an electrode portion 62 to which a voltage of 1 kilovolt is applied and a support portion 61 for holding and insulating the electrode portion. In this embodiment, four recording electrodes 3 are used.
Although the electrode portion 62 is integrally formed in correspondence with No. 4, it may be formed in four pieces corresponding to each recording electrode 34.

Further, a paper transport unit 50 is provided below the apparatus. The paper transport unit 50 includes a paper cassette 52 that stores paper 51 and an eject roller 5.
3, a sheet reversing roller 54, a conveyance guide 55, a delivery roller 56, and a conveyance roller 57. Each roller can rotate in the direction of the arrow in the figure and can convey a sheet.

Further, the fixing unit 4 is provided downstream in the paper conveying direction.
0 is arranged. The fixing unit 40 includes the heater 4
It is composed of a heat roller 43 containing 2 and a pressure roller 41.

Above the apparatus, a controller section 71 for performing data processing required for recording and a power source section 70 for controlling driving and voltage control are provided.

Next, the operation of this embodiment will be described.

When data is sent from an external computer, the device starts operating. In the process unit 20, the stored toner 16 is given a negative charging property, is placed on the toner carrying roller 23, and is carried to a position in contact with the aperture electrode body 30.

In each of the recording electrodes 34 constituting the aperture electrode body 30, the signal from the control voltage applying circuit 26 is transmitted to the control electrode 33 through the conductor portion. As a result, the control voltage application circuit 26 selectively applies 0 volt and 40 volt to the control electrode 33. At this time, an electric field is generated between the toner carrying roller 23 and the control electrode 33, which are grounded, and the toner sandwiched between the aperture electrode body 30 and the toner carrying roller 23 receives an electrostatic force to perform recording control. it can. That is, when 0 volt is applied, the toner remains stationary without moving to the aperture 32, but when 40 volt is applied, the negatively charged toner passes through the aperture 32 and then fly by the electric field formed by the counter electrode 60.

At the same time when the apparatus is started, the paper transport unit 50
From, the paper 51 is sent out. That is, the semi-circular kicking-out roller 53 causes the sheet cassette 52 to move the sheet 5
1 is sent out, the carrying direction is changed by the paper reversing roller 54, and then held and sent by the carrying guide 55 and the carrying roller 57. When the paper 51 comes directly under the aperture 32 of the recording electrode 34, the toner 16 flies and adheres.

Through the printing process as described above, the paper 51
The four colors of yellow, magenta, cyan, and black are overlaid on top of each other. At this time, the toner carrying rollers 23 are accurately positioned by the integrated member 37, so that the aperture 32 of the aperture electrode body 30 is also positioned. Since they are arranged accurately, it is possible to accurately overlay each color.
That is, the aperture 32 accurately positioned with respect to each toner carrying roller 23 has its discharge position set without displacement or distortion with respect to the support due to the strict arrangement of the toner carrying rollers 23 by the integrated member 37. It as a result,
Conventionally, color misregistration due to a positioning error, which has been a problem between apertures of respective colors, can be eliminated, and good image quality can be obtained.

After that, the sheet 51 on which the toner image is formed is conveyed to the fixing unit 40. And
Here, the image on the sheet is fixed by being brought into pressure contact with the heat roller 43 and the pressure roller 41. Since this fixing method is a general method, detailed description is omitted. The image-formed sheet is conveyed to the discharge port 12 via the conveyance guide 55 and output.

The present invention is not limited to the embodiments described in detail above, and various modifications can be made without departing from the spirit of the invention.

For example, in the above embodiment, the control voltage of the aperture corresponding to the non-image portion is set to 0V, but this may be a negative voltage. In this case, an image with less fogging can be obtained. Further, in the above embodiment, the aperture electrode body is used as the toner flow control means, but it is also possible to use, for example, a knitted electrode body as described in the specification of US Pat. No. 5,036,341.

Further, although the present embodiment uses the aperture electrode body divided for each color, an aperture electrode body integrated with each color as shown in Japanese Patent Application No. 3-289922 may be applied.

Further, in this embodiment, a high-rigidity integrated member is arranged and used as the integration means, but if the body of the recording unit itself has high rigidity and can function as an integrated member, It may be used without adding any member.

[0035]

As is apparent from the above description, according to the image forming apparatus of the present invention, it is possible to print at a controlled position without causing a positional shift when overlapping each color. become. As a result, it is possible to perform output that is excellent in image quality without color shift.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment embodying the configuration of an image forming apparatus of the present invention.

FIG. 2 is a cross-sectional view showing a recording unit.

FIG. 3 is a perspective view showing a supported state of a toner carrying roller.

FIG. 4 is a perspective view showing a configuration of an aperture electrode body used in the image forming apparatus of the present invention.

[Explanation of symbols]

 16 Toner 20 Process Unit 21 Recording Unit 22 Toner Supply Unit 30 Aperture Electrode Body 32 Aperture 33 Control Electrode 34 Recording Electrode 37 Integrated Member

Claims (5)

[Claims] 1. A plurality of recording units, each of which comprises a carrier for supporting and supplying charged particles, and an electric field control means for arranging the carrier via the charged particles and directly controlling the flow of the charged particles by an electric field. An image forming apparatus having the above-mentioned: wherein the plurality of recording units are integrally formed. 2. Each carrier of the plurality of recording units,
The image forming apparatus according to claim 1, wherein the image forming apparatus is supported by a common supporting member. 3. The image forming apparatus according to claim 1, wherein the plurality of recording units are linearly arranged along a conveying direction of the image receiving body. 4. The carrier of each of the plurality of recording units,
The image forming apparatus according to claim 2, wherein the image forming apparatus comprises a toner carrying roller, and each end of the toner carrying roller is supported by a single common supporting member. 5. The image forming apparatus according to claim 1, wherein the electric field control means of the plurality of recording units are integrally formed.