JPH05193183A - Image forming apparatus - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide an image forming apparatus capable of forming a clear color image without disturbance. [Structure] The yellow toner 13 that has been negatively charged in the previous step has already adhered to the support 17, but the magenta toner 14 has the opposite charging polarity, so the yellow toner 1
It is held by the support 17 according to the flying electric field generated by the back electrode 9 to which a negative high voltage is applied, without being disturbed by the negative charges of No. 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a printer,
The present invention relates to an image forming apparatus that can be used for plotters, facsimiles, and the like.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus for controlling the passage of toner particles through an aperture by applying an image signal to an electrode having an aperture to obtain a color image on a support is disclosed in Japanese Patent Application No. 3-30213. Has been proposed in. This image forming apparatus is provided with a plurality of pixel forming devices corresponding to a plurality of colors, and when the support is transported, in the pixel forming device having the toner of the first color, the charged toner changes the aperture electrode body. Is supplied in the vicinity of the reference electrode aperture.
At this time, when a voltage having a polarity opposite to the charge polarity of the toner is applied to the control electrode according to the image signal, an electric field that applies a force to the charged toner in the direction from the reference electrode to the control electrode is applied to the aperture of the applied control electrode. Is formed. Toner is drawn from the reference electrode side of the aperture to the control electrode side,
It flies and is held on a support to form an image portion. By applying a voltage having the same polarity as the charging polarity of the toner to the control electrode of the aperture corresponding to the non-image portion, the electric field formed in the aperture suppresses the toner from passing through the aperture.

Next, while forming the image of the first color as described above, the same process as that of the pixel forming device having the toner of the first color is performed, and the pixel forming device of the next different color is used. Color pixels are formed overlying the first color image.

In this way, the required number of color pixel forming devices can be used to form images of the required colors in an overlapping manner, resulting in a color image.

[0005]

However, since the toners of the plurality of pixel forming devices have the same charge polarity, when the pixels of the second color which are different from each other are formed in a superimposed manner on the image of the first color, they are supported. There is a problem that the flying toner electric field is disturbed by the first toner on the body, the second toner does not fly to an intended position on the support, and the image is disturbed.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus capable of forming a clear color image without disturbance.

[0007]

In order to achieve this object, the image forming apparatus of the present invention is provided with a means for conveying a support and a conveying path of the support, and sandwiches a layer of an insulator. An aperture electrode having a reference electrode on one surface side and one or more control electrodes insulated from each other on the other side, and having two or more apertures penetrating three layers for each insulated control electrode. Image forming apparatus comprising a plurality of pixel forming devices each including a body, a means for selectively applying a potential between the control electrode of the aperture electrode body and the reference electrode, and a supplying means for supplying the charged toner to the vicinity of the aperture of the reference electrode. In the apparatus, a plurality of pixel forming devices are arranged so that the charging polarities of the charged toner are alternated.

[0008]

According to the present invention having the above-mentioned structure, in the pixel forming apparatus for the second color toner, the toner having the polarity opposite to the polarity of the toner of the pixel forming apparatus in the previous stage is used to form the image on the support. Form and output a color image.

[0009]

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 embodiment embodying the present invention. In FIG. 1, a transport roller 18 is arranged to transport the support 17 in the arrow direction. Support 17
Three pixel forming devices 10, 11 and 12 are provided side by side so as to face the lower surface of the support member in the conveyance path of No. 3, and yellow toner 13, magenta toner 14 and cyan toner 15 are housed in the toner case 16, respectively. Has been done. The yellow toner 13 and the cyan toner 15 are negatively charged toner,
The magenta toner 14 is a positively charged toner.

An aperture electrode body 1 is provided on the top of each pixel forming device. A toner case 16 is provided on the lower surface side of the aperture electrode body 1. In the toner case 16, a brush roller 20 and a supply roller 23 arranged in parallel with the brush roller 20 are arranged. The brush of the brush roller 20 and the supply roller 23 are in contact with each other. A brush scraping blade 24 is in contact with the brush roller 20 at a position before rotating on the aperture surface.

The reference electrode 3 is grounded as shown in FIG. Yellow and cyan color pixel forming apparatus 1
The control electrodes 4 of 0 and 12 are control voltage drive circuits 8S that generate a positive voltage in accordance with image signals of yellow and cyan colors,
The control electrode 4 of the magenta pixel forming device is connected to a control voltage drive circuit 8H that generates a negative voltage according to the magenta image signal.

Each pixel forming device 10 with the support 17 interposed therebetween.
A back electrode 19 is provided on the opposite side of 11 and 12. The back electrodes 19 of the yellow and cyan pixel forming devices 10 and 12 are connected to a positive DC power supply 30S, and the back electrodes 19 of the magenta pixel forming device 11 are connected to a negative DC power supply 30H.

As shown in detail in FIG. 2, the aperture electrode body 1 has a continuous reference electrode 3 on one surface of the insulating layer 2 and a control electrode 4 divided on the other surface. A large number of apertures 6 penetrating the layer 2 and the control electrode 4 are formed in a row in the width of the support 17.

The operation of the above structure will be described in detail below.

The support 17 is transported by the transport roller 18 in the direction of the arrow so as to face the aperture electrode body 1 of the pixel forming device of three colors in order.

First, the yellow pixel forming apparatus 1
0, the brush roller 20 and the supply roller 23
The toner 13 is rotated by the rotation in the direction of the arrow to move the toner 13 to the brush roller 2.
It is carried by 0 brushes. At this time, the toner 13 rubs against the brush or the supply roller 23 and is negatively charged. The charged toner 13 is conveyed toward the vicinity of the brush scraping blade 24 by the rotation of the brush roller 20. The brush near the brush scraping blade 24 repels the negatively charged toner 13 by its elasticity when scratched by the brush scraping blade 24, and the toner 13 becomes a cloud shape and is supplied to the vicinity of the reference electrode aperture 6 of the aperture electrode body 1. To be done.

At this time, the pixel forming apparatus 10 applies a voltage to the control electrode 4 by the control electrode drive circuit 8S according to the yellow image signal corresponding to the position of the support 17 facing the aperture electrode body 1.

When a positive voltage is applied, an electric force line from the control electrode 4 to the reference electrode 3 is formed in the aperture 6 of the applied control electrode 4, and the toner 13 charged negatively has an aperture. An image is ejected from the side of the reference electrode 3 to the side of the control electrode 4, and further, is jetted and held on the support body 17 by the flying electric field formed by the back electrode 19 to which a positive high voltage is applied by the positive DC power source 30S To form a part.

By applying the same potential or a negative voltage as the reference electrode 3 to the control electrode 4 of the aperture 6 corresponding to the non-image portion, the flying electric field by the back electrode 19 is shielded or the reference electrode is provided in the aperture 6. By forming an electric force line from 3 to the control electrode 4, the toner 13 is prevented from passing through the aperture.

In this way, a yellow image is formed on the support 17.

Next, in the magenta pixel forming apparatus 10, the toner 14 is carried on the brush of the brush roller 20 by the rotation of the brush roller 20 and the supply roller 23 in the direction of the arrow. At this time, the toner 14 rubs against the brush or the supply roller 23 and is positively charged. The charged toner 14 is conveyed toward the vicinity of the brush scraping blade 24 by the rotation of the brush roller 20. The brush near the brush scraping blade 24 is the brush scraping blade 2
When the toner 14 is scratched by 4, the toner 14 positively charged is repelled by its elasticity, and the toner 14 is supplied in the vicinity of the reference electrode aperture 6 of the aperture electrode body 1 in a cloud shape.

At this time, the pixel forming apparatus 10 applies a voltage to the control electrode 4 by the control electrode drive circuit 8H according to the magenta image signal corresponding to the position of the support 17 facing the aperture electrode body 1.

When a negative voltage is applied, an electric force line from the reference electrode 3 to the control electrode 4 is formed in the aperture 6 of the applied control electrode 4, and the toner 14 charged positively has an aperture. An image is ejected from the side of the reference electrode 3 to the side of the control electrode 4, and further, is jetted and held on the support body 17 by the flying electric field formed by the back electrode 19 to which a negative high voltage is applied by the negative DC power source 30H. To form a part.

At this time, the yellow toner 13 which has been negatively charged in the previous step has already adhered to the support 17, but the magenta toner 14 has the opposite charging polarity, so that the negative toner 13 of the yellow toner 13 is negative. It is held on the support 17 according to the flying electric field by the back electrode 9 to which a negative high voltage is applied, without being disturbed by electric charges.

By applying the same potential or a positive voltage as the reference electrode 3 to the control electrode 4 of the aperture 6 corresponding to the non-image portion, the flying electric field by the back electrode 19 is shielded or the control electrode is provided in the aperture 6. By forming an electric force line from 4 toward the reference electrode 3, the toner 14 is prevented from passing through the aperture.

In this manner, a magenta image is formed on the yellow image on the support 17 in a superimposed manner.

Finally, the cyan pixel forming device 12 performs the same operation as the yellow pixel forming device 10 to form a cyan image by superposing it on the yellow and magenta images. At this time, the yellow toner 13 that was already negatively charged and the magenta toner 1 that was positively charged in the previous stage
3 is attached to the support 17, but the cyan toner 15
Has a polarity opposite to that of the magenta toner 14,
The positive charge of the magenta toner 14 on the outermost layer is not disturbed, and the influence of the negative charge of the yellow toner 13 is offset by the passage of time and the positive charge of the magenta toner 14. Therefore, it is held on the support 17 in accordance with the flying electric field generated by the back electrode 9 to which a positive high voltage is applied.

In this way, while the support 17 passes over the three-color pixel forming device, the three-color images are superimposed and formed to obtain a color image.

Further, the present invention is not limited to the above-mentioned embodiment and can be modified within the scope not departing from the gist thereof.

[0031]

As is apparent from the above description, according to the present invention, the toner charged in the pixel forming device in the previous stage and the toner in the pixel forming device in the next stage have opposite charge polarities. Therefore, the toner is retained on the support according to the flying electric field by the back electrode to which the high voltage is applied, without being disturbed by the electric charge of the toner at the previous stage already attached to the support.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment embodying the present invention.

FIG. 2 is a perspective view showing details of an aperture electrode body.

[Explanation of symbols]

 1 Aperture Electrode 2 Insulation Layer 3 Reference Electrode 4 Control Electrode 6 Aperture 8 Control Electrode Driving Circuit 10 Yellow Color Pixel Forming Device 11 Magenta Color Pixel Forming Device 12 Cyan Color Pixel Forming Device 13 Yellow Color Toner 14 Magenta Color Toner 15 Cyan Color Toner 18 transport roller 20 brush roller 23 supply roller 24 brush scraping blade

Claims (1)

[Claims] 1. A means for transporting a support, and one or more controls which are arranged in a transport path of the support and are insulated from each other by a reference electrode on one side and an opposite side with an insulator layer interposed therebetween. An aperture electrode body having an electrode and having two or more apertures penetrating three layers for each insulated control electrode, and a potential is selectively applied between the control electrode and the reference electrode of the aperture electrode body. In the image forming apparatus having a plurality of pixel forming devices each including a charging unit and a supplying unit that supplies the charged toner to the vicinity of the aperture of the reference electrode, a plurality of pixel forming units are provided so that the charging polarities of the charged toner are alternated. An image forming apparatus characterized by being arranged.