JPH04332660A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image forming device forming a sharp toner image of a small dot diameter. CONSTITUTION:Since the tip end of a back electrode 11 opposed to a substrate 10 is shaped into a comb form and remarkably small in area, a flying electric field formed by the back electrode 11 converges, and a toner 22 flies toward the tip ends of the back electrode 11. In this manner, a sharp image of a small dot diameter is formed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to copying machines, printers,
The present invention relates to an image forming apparatus that can be used for plotters, facsimile machines, etc.

0002

2. Description of the Related Art Conventionally, an image recording apparatus for controlling the passage of toner particles through an aperture and obtaining an image on a support by applying an image signal to an electrode having an aperture was proposed in US Pat. No. 3,689,935. There is. This proposal consists of a continuous reference electrode on one side with an insulator layer in between, and a plurality of control electrodes insulated from each other on the other side, with each insulated control electrode penetrating through three layers. an aperture electrode body having one row of apertures;
means for selectively applying an electric potential between the control electrode and the reference electrode; means for projecting charged particles such that the flow of toner particles through the aperture is modulated by the applied electric potential; and a support and an aperture electrode assembly. and means for moving the support body relative to each other to position the support body in the particle flow path.

0003

[Problems to be Solved by the Invention] However, in conventional devices, the area of the back electrode facing the aperture is large, and the electric lines of force do not concentrate, and the dot diameter formed by toner is larger than the opening area of the aperture. As a result, the image becomes blurred and a clear image cannot be formed. 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 that forms clear images.

0004

[Means for Solving the Problems] In order to achieve this object, the image forming apparatus of the present invention includes a carrier carrying toner and an insulating layer sandwiched between two electrodes, and an aperture electrode provided with an opening. and a counter electrode provided opposite to the aperture electrode across a support, the charged toner is carried by the carrier up to the vicinity of the aperture electrode,
In an image forming apparatus that forms an image by controlling modulation using the aperture electrode, the image is caused to fly toward the counter electrode through the opening, and is attracted to the support.
It has a counter electrode whose surface area facing the aperture electrode is less than or equal to the area of the opening.

[0005]

[Operation] According to the present invention having the above configuration, the charged toner is carried by the carrier up to the vicinity of the aperture electrode, and by controlling the modulation by the aperture electrode, it passes through the opening and is directed to the aperture electrode of the counter electrode. An image is formed by flying to a very small area and adsorbing it to a support.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an image forming apparatus 100 according to an embodiment of the present invention. As shown in detail in FIG. 2, the aperture electrode body 1 has a reference electrode 3 on the toner supply source side of the insulating layer 2 and a control electrode 4 on the support side.
A large number of apertures 6 penetrating the insulating layer 2 and the control electrode 4 are formed in a line corresponding to the width of the support. In FIG. 1, on the left side of the image forming apparatus 100, there is a cassette 50 that stores the support 10, and a half-moon roller 5 that supplies the support 10 one by one.
1, a support supply roller 52 for feeding out the support 10, and a chute 53 are disposed downstream.

Downstream, on the control electrode side of the aperture electrode body 1, there are a support conveying roller 14, a sensor 57, and
A back electrode 11 is disposed in contact with the back surface of the support 10, and each control electrode 4 is connected to a control voltage drive circuit 8 that generates a voltage based on an image signal. The back electrode 11 is connected to a negative high voltage power source 12.

The back electrode 11 is attached to the support 1 as shown in FIG.
The part facing 0 is comb-shaped.

On the reference electrode side of the aperture electrode body 1, a toner conveyance belt 26 is wound between a drive roller 20 and a backup roller 24, and on the back side of the conveyance belt, which faces the aperture electrode body, a cam roller with an elliptical cross section is arranged. 2
7, a static elimination brush 31 is arranged on the upstream side thereof. These are toner 22 stored near the supply roller 23.
, and in contact with the supply roller 23 and the toner conveying belt 2
The toner case 21 is housed together with a supporting roller 30 having a gap of 0.1 to 0.4 mm with respect to the toner case 21. The surface of the supply roller 23 is made of sponge or the like, and the surface of the support roller 30 is made of resin.

Further downstream, a fixing device 13 and a chute 5 are installed.
4, a discharge roller 55, and a tray 56 are provided.

The operation of the above-described configuration will be explained in detail below.

The support body 10 housed in the cassette 50 is
The sheets are fed out one by one by the half-moon roller 51 and placed in the chute 5.
3, and is conveyed to the support conveyance roller 14 by the support supply roller 52. When the tip of the support 10 is detected by the sensor 57, the toner conveying belt 26 rotates between the backup roller 24 and the drive roller 20 due to the rotation of the drive roller 20 in the direction of the arrow, and the toner 22 is rotated by the rotation of the supply roller 23 in the direction of the arrow. After being rubbed by the carrier roller 30 and positively charged by friction, the toner is carried on the toner conveying belt 26 by electrostatic coating using a high-voltage power source.

The supported toner is conveyed toward the surface facing the aperture electrode, and at the upstream side of this position, the static eliminating brush 31 is used to remove the static electricity from the conveyor belt 26 from the back side of the conveyor belt 26.
is removed. Since the cam roller is rotating at the position facing the aperture electrode, the surface of the conveyor belt 26 vibrates. Therefore, the toner carried on the conveyor belt 26 receives a force due to the vibrational acceleration of the conveyor belt 26 and is released from adhesion forces such as mirror image force, van der Waals force, and electrostatic force with the conveyor belt 26 .

On the other hand, at this time, when a negative voltage is applied to the control electrode 4 in accordance with an image signal from a storage means (not shown), the aperture 6 of the control electrode 4 to which the voltage is applied is directed from the back surface of the aperture 6 to the front surface. The toner 22, which is positively charged with electric lines of force formed therein, is pulled out from the back surface of the aperture 6 to the front surface, and is further blown onto the support by the flying electric field formed by the back electrode 11. is held to form an image portion.

By applying the same potential as the reference electrode 3 or a positive voltage to the control electrode 4 of the aperture 6 corresponding to the non-image area, the flying electric field caused by the back electrode 11 can be shielded, or the electric field can be placed inside the aperture 6. The toner 22 is prevented from passing through the aperture 6 by forming electric lines of force from the front side toward the reference electrode 3 on the back side. This process is performed on the support 10
By repeating this while being conveyed, a toner image is formed on the entire surface of the support 10.

At this time, since the tip of the back electrode 11 facing the support 10 has a skewer shape and the area of the tip is extremely small, the flying electric field formed by the back electrode 11 is concentrated and the toner is 22 flies toward the tip of the back electrode 11, forming a clear image with a small dot diameter.

The support on which the toner image is formed is fixed to the fixing device 1.
3, the image is fixed on the support 10. Furthermore, the tray 5 is guided by the chute 54 and is driven by the ejection roller 55.
It is discharged at 6.

Furthermore, the present invention is not limited to the above-described embodiments, and can be modified within the scope of the invention.

For example, if the tip of the back electrode is made flat,
It may be made into a spherical shape.

[0021]

[Effect of the invention] As is clear from the detailed description above,
According to the present invention, the flying electric field formed by the back electrode is concentrated and the toner flies toward the tip of the back electrode, so that a clear image with a small dot diameter can be formed.

[Brief explanation 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.

FIG. 3 is a perspective view showing details of a back electrode.

[Explanation of symbols]

1 Aperture electrode body 2 Insulating layer 3 Reference electrode 4 Control electrode 6 Aperture 8 Control voltage drive circuit 10 Support 11　Back electrode 12 High voltage power supply 22 Toner 23 Supply roller 24 Backup roller 26 Toner conveyance belt

Claims (1)

[Claims] 1. A carrier carrying toner, an aperture electrode in which an insulating layer is sandwiched between two electrodes and an opening is provided, and a counter electrode provided opposite to the aperture electrode with a support in between. The charged toner is carried by a carrier up to the vicinity of the aperture electrode, and the aperture electrode modulates and controls the toner so that it passes through the opening and flies toward the counter electrode and is adsorbed to the support. An image forming apparatus for forming an image, characterized in that the area of opposing surfaces of the counter electrode is set to be less than or equal to the area of the opening.