JPH07132634A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To obtain an image of high quality without requiring the alteration of complicated wiring patterns to an aperture electrode. CONSTITUTION:Rear electrodes, apertures 18a and a toner carrying roller are arranged on the downstream side with respect to the feed direction of recording paper while rear electrodes, apertures 18b and a toner carrying roller are arranged on the upstream side. Charged toner is carried by two toner carrying rollers to be fed to the opposed surfaces of the apertures 18a, 18b. When voltage is applied to the apertures 18a, 18b, the toner on the toner carrying rollers is flown to form an image on recording paper. At this time, the toner on the toner carrying rollers is always affected only by the voltage applied to the apertures 18a, 18b. Therefore, by feeding toner to two rows of the apertures 18a, 18b by two carrying rollers, the effect due to the voltage of one aperture row is not imparted to the other aperture row.

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.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus,
As shown in the specification of US Pat. No. 3,689,935, an electrode provided with a plurality of openings (hereinafter referred to as an aperture) is provided, and a voltage is applied to the electrode based on image data. In some cases, the toner particles are controlled so that they can pass through the aperture, and an image is formed on the support by the passed toner particles.

In such an image forming apparatus, a flat plate made of an insulating material, a continuous reference electrode formed on one surface of the flat plate, and a plurality of insulated controls formed on the other surface of the flat plate. An electrode, an aperture electrode body in which two rows of apertures are formed through each of the control electrodes for each control electrode, and potential applying means for selectively applying a potential between the reference electrode and the control electrode are applied. A supply means for supplying charged toner particles so that the flow of the toner particles passing through the aperture is modulated by an electric potential, and the support is positioned in the particle flow path so that the support and the aperture electrode body can move relative to each other. It is composed of a transport means.

On the other hand, in Japanese Unexamined Patent Publication No. 2-226261, by disposing the aperture electrode body so that the reference electrode faces the support side and the control electrode faces the toner supplying side, The voltage applied to the control electrode when toner particles are not adhered to, that is, when forming a blank portion of an image can be suppressed to about 1/4 of that of the image forming apparatus of the above-mentioned US patent. Have been described.

Particularly, in the aperture electrode body in which two rows of apertures are formed for each control electrode, a wiring pattern for the control electrode is formed toward both sides of the aperture centering on the aperture, and toner particles are collected. When the carrying roller is used to supply the vicinity of the aperture, the wiring pattern of the aperture electrode body having the two rows of apertures is directed toward the central aperture from the downstream side and the upstream side with respect to the rotation of the carrying roller. It is extended.

[0006]

However, in the above configuration, since the wiring pattern extends from the downstream side and the upstream side toward the center aperture with respect to the rotation of the carrying roller, the potential is applied to the aperture on the downstream side. Is applied,
The influence appears on the toner output from the aperture on the upstream side. Therefore, there is a problem in that the appearance of the toner output from the aperture on the upstream side is different between when the potential is applied to the aperture on the downstream side and when the potential is not applied, and the image quality is deteriorated.

In order to solve this problem, if the wiring patterns of aperture electrode bodies having two rows of apertures are laid in the same direction, the spacing between the wirings will be narrowed, resulting in a reduction in the yield during production and cost. There is a problem that is high.

The present invention has been made in order to solve the above-mentioned problems, and does not require a complicated wiring pattern change to the aperture electrode body and has the same number of toner carriers as the number of aperture rows. It is an object of the present invention to provide an image forming apparatus with high image quality by using.

[0009]

In order to achieve this object, the image forming apparatus of the present invention has at least two apertures.
An aperture electrode having more than one row, and at least two or more toner carriers that carry toner charged in the aperture;
By providing an image signal to the aperture electrode, it is possible to control the passage of the charged toner through the aperture, and a control means for forming an image on the toner carrier and the support provided on the opposite side with the aperture electrode interposed therebetween. ing.

[0010]

The image forming apparatus of the present invention having the above structure is
The charged toner is carried on at least two toner carrying members, respectively, and is carried to each aperture facing surface. That is, the toner carrier, which is the support and is downstream in the transport direction of the recording paper, transports the toner to the aperture that is downstream in the transport direction of the recording paper. When a voltage is applied to the aperture on the downstream side, the toner on the toner carrier on the downstream side flies and forms an image on the recording paper. At this time, the toner on the toner carrier on the downstream side is always affected only by the voltage due to the aperture on the downstream side.

On the other hand, the toner carrier on the upstream side in the conveying direction of the recording paper conveys the toner to the aperture on the upstream side in the conveying direction of the recording paper. When a voltage is applied to the aperture on the upstream side, the toner on the toner carrier on the upstream side flies and forms an image on the recording paper. At this time, the toner on the upstream side toner carrier is always affected only by the voltage due to the upstream side aperture.

Therefore, the toner is conveyed to at least two rows of apertures by at least two carrying rollers, so that the influence of the voltage of one aperture row does not affect other aperture rows.

[0013]

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 diagram showing an aperture electrode body of an image forming apparatus embodying the present invention. Aperture electrode body 10
As shown in detail in FIG. 1A and FIG. 1B, the insulating layer 12 has a control electrode 16 on the recording paper 14 side.
2 and a plurality of apertures 18a and 18b penetrating the control electrode 16 are formed in the width of the recording paper 14 (left and right direction in FIG. 1). The aperture 18a is formed on the downstream side (upper side in FIG. 1) with respect to the recording paper 14 conveyance direction (arrow B direction), and the aperture 18b is formed on the upstream side (FIG. 1) with respect to the recording paper 14 conveyance direction. Below), and the aperture 1
8a and 18b are alternately arranged in a staggered pattern.

Further, FIG. 2 is a schematic view of an image forming apparatus embodying the present invention, in which the control electrode 1 of the aperture electrode body 10 is shown.
On the 6 side, the recording paper 14 is conveyed by a pair of recording paper conveying rollers 20, and rear electrodes 22a and 22b are arranged so as to contact the rear surface of the recording paper 14, and the rear electrode 22a is in the conveying direction of the recording paper 14. Downstream of the back electrode 22
b is provided on the upstream side with respect to the conveyance direction of the recording paper 14. The fixing device 24 is arranged at the destination of the recording paper 14. In addition, each control electrode 16 is connected to a control voltage drive circuit 26 that generates a voltage according to an image signal. Further, the back electrodes 22a and 22b are connected to a positive high voltage power supply 28.

A toner carrying roller 30a and a supply roller 34a for supplying the toner 32 to the toner carrying roller 30a are provided on the side opposite to the control electrode 16 of the aperture electrode body 10 and on the downstream side with respect to the conveying direction of the recording paper 14. , And a toner case 36 for housing the toner 32. The supply roller 34a is made of urethane foam rubber,
The positional relationship is such that it is pressed against the toner carrying roller 30a. Further, on the upstream side with respect to the conveyance direction of the recording paper 14,
The toner carrying roller 30b, the supply roller 34b for supplying the toner 32 to the toner carrying roller 30b, and the toner 32
And a toner case 36 that accommodates the toner. The supply roller 34b is formed of urethane foam rubber and is in a positional relationship of being pressed against the toner carrying roller 30b. The toner carrying surfaces of the carrying rollers 30a and 30b are connected to 0V.

Rotation of the toner carrying roller 30a is transmitted from a motor (not shown) and is rotatable counterclockwise with respect to the toner case 36. The supply roller 34a is rotated by the motor (not shown) against the toner case 36. It can be rotated clockwise. Rotation of the toner carrying roller 30b is transmitted from a motor (not shown) so that the toner carrying roller 30b can rotate clockwise with respect to the toner case 36. The supply roller 34b rotates clockwise with respect to the toner case 36 by a motor (not shown). It is rotatable.

Further, collection boxes 38a and 38b for collecting the toner not used for image formation are provided on the downstream side of the respective rotation directions of the toner carrying rollers 30a and 30b. Further, the toner carrying rollers 30a, 30b
A layer regulation plate 40 for thinning the thickness of the toner 32 carried on the toner carrying rollers 30a and 30b to a constant thickness (around 10 μm) is arranged between them. The toner carrying surfaces of the carrying rollers 30a and 30b are connected to 0V.

Next, the image forming operation in the image forming apparatus having such a configuration will be described.

First, when the power is turned on, the toner carrying roller 30a rotates counterclockwise and the supply roller 34a also rotates counterclockwise. Therefore, the toner carrying roller 30
Since the rotation direction of a and the supply roller 34a is different in the contact portion, the toner 32 carried on the supply roller 34a is rubbed against the toner carrying roller 30a, and is slightly negatively charged and carried on the toner carrying roller 30a. To be done. The carried toner 32 is thinned by the layer regulation plate 40 to a thickness of about 10 μm and sufficiently charged. At this time, the carried toner 32 is conveyed toward the aperture electrode body 10 by the rotation of the toner carrying roller 30a.

At this time, when the control voltage drive circuit 26 applies a positive voltage to the control electrode 16 in accordance with the image signal, the surface of the toner carrying roller 30a is connected to 0V, so that the toner carrying roller 30a is in the vicinity thereof. Then, in the aperture 18a of the applied control electrode 16, an electric force line is formed from the surface of the toner carrying roller 30a on the back surface side of the aperture 18a to the surface of the aperture 18a. Therefore, the negatively charged toner 32 is
The aperture 18a is drawn from the back surface to the front surface, and further, is fly and is held on the recording paper 14 by the flying electric field formed by the back electrode 22a to form the image portion 42.

On the other hand, the toner carrying roller 30b rotates clockwise, and the supply roller 34b also rotates clockwise. Therefore, since the toner carrying roller 30b and the supplying roller 34b have different rotation directions at the contact portions, the toner 32 carried on the supplying roller 34b is rubbed against the toner carrying roller 30b and is slightly negatively charged to carry the toner. It is carried on the roller 30b. The carried toner 32 is thinned by the layer regulation plate 40 to a thickness of about 10 μm and sufficiently charged. At this time, the carried toner 32 is conveyed toward the aperture electrode body 10 by the rotation of the toner carrying roller 30b.

At this time, when the control voltage drive circuit 26 applies a positive voltage to the control electrode 16 according to the image signal,
Since the toner carrying roller 30b is grounded and its surface is at 0V, the aperture 18 formed on the applied control electrode 16 is near the toner carrying roller 30b.
Lines of electric force are formed in b from the surface of the toner carrying roller 30b on the back side of the aperture 18b to the surface of the aperture 18b. Then, the negatively charged toner 32 is extracted from the back surface of the aperture 18b to the front surface thereof, and further, is jumped onto the recording paper 14 by the flying electric field formed by the back electrode 22b, and is held, whereby the image portion is formed. 42 is formed.

The aperture 18a corresponding to the non-image part
To the control electrode 16 of the toner carrying roller 30a by applying the same potential or a negative potential to the surface of the toner carrying roller 30a to shield the flying electric field from the back electrode 22a, or from the control electrode 16 to the toner carrying roller 30a in the aperture 18a. Lines of electric force directed to the surface of the toner are formed, and the passage of the toner 32 through the aperture 18a is suppressed.

On the other hand, the aperture 18b corresponding to the non-image part
As described above, the same electric potential as the surface of the toner carrying roller 30b or a negative electric potential is applied to the control electrode 16 of the rear electrode 22b to shield the flying electric field by the back electrode 22b or to control the electric field in the aperture 18b. Electric lines of force are formed from the electrode 16 toward the surface of the toner carrying roller 30b to suppress passage of the toner 32 through the aperture 18b.

In the toner 32 on the toner carrying roller 30a, the distance between the toner carrying roller 30a and the aperture 18a is determined by the distance between the toner carrying roller 30a and the aperture 18b.
Is sufficiently shorter than the distance between
An image is formed only by the potential of the control electrode of the aperture 18a without being affected by the control electrode 16 of. On the other hand, the toner 32 on the toner carrying roller 30b also controls the aperture 18a because the distance between the toner carrying roller 30b and the aperture 18b is sufficiently shorter than the distance between the toner carrying roller 30b and the aperture 18a. An image is formed only by the potential of the control electrode of the aperture 18b without being affected by the electrode 16.

By repeating such a process while conveying the recording paper 14, a toner image is formed on the entire surface of the recording paper 14. Then, the recording paper 1 on which the toner image is formed
4 passes through the fixing device 24 to form an image on the recording paper 14
Fixed on top.

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, the toner 32 described in the above embodiment is an example of a one-component non-magnetic toner that is usually used in electrophotographic copying machines and the like, but this method is used only for this toner. However, a process using a one-component magnetic toner or the like is also possible.

In the above embodiment, the toner carrying roller 3 is used.
The rotation directions of 0a and 30b are opposite to each other, but this method is not limited to this rotation direction, and the two may have the same rotation direction or the rotation direction opposite to that of the embodiment.

[0031]

As is apparent from the above description,
According to the image forming apparatus of the present invention, a high-quality image can be obtained by using the same number of toner carriers as the number of aperture rows without the need to change a complicated wiring pattern to the aperture electrode body. You can

[Brief description of drawings]

1 (a) is a plan view of an aperture electrode body of the present invention, and FIG. 1 (b) is a sectional view taken along the line AA of FIG. 1 (a).

FIG. 2 is a schematic view showing an image forming apparatus embodying the present invention.

[Explanation of symbols]

 10 Aperture Electrode Body 12 Insulating Layer 14 Recording Paper 16 Control Electrode 18a Aperture 18b Aperture 20 Recording Paper Conveying Roller 22a Rear Electrode 22b Rear Electrode 24 Fixing Device 26 Control Voltage Driving Circuit 28 High Voltage Power Supply 32 Toner 30a Toner Carrying Roller 30b Toner Carrying Roller 34a Supply roller 34b Supply roller 36 Toner case 38a Collection box 38b Collection box

Claims (4)

[Claims] 1. An aperture electrode having at least two rows of apertures, at least two or more toner carriers carrying toner charged in the aperture, and being charged by applying an image signal to the aperture electrode. An image forming apparatus comprising: a control unit that controls the passage of toner through the aperture and forms an image on a support provided on the opposite side of the toner carrier and the aperture electrode. 2. The image forming apparatus according to claim 1, wherein the number of aperture rows is equal to the number of toner carriers. 3. The image forming apparatus according to claim 1, wherein the number of regulating plates for keeping the thickness of the toner on the toner carrier constant is ½ of the number of toner carriers. 4. The image forming apparatus according to claim 1, wherein the number of toner cases for accommodating the toner is 1/2 of the number of the toner carrying members.