JPH07117263A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To form an image of a high image quality at a low cost as a result of lowering a drive voltage by providing means for forming different electric fields of alternately different directions at an upstream side of a toner supplying direction of a toner carrier in an image forming apparatus. CONSTITUTION:A plurality of alternate electric field electrodes 5 each having a width of 30mum are formed at an interval of 130mum along apertures 6 before apertures 6 of an opposite side surface to a control electrode forming surface. Since voltages of +100V and -100V are alternately applied to the plurality of the electrodes 5, electric fields of alternating directions are formed between the electrodes 5 and a toner carrier roller 14. Toner on the roller 14 is alternately effected and fluctuated by forces of directions of the electrode 1 and the roller 14 by the alternate electric fields fed under the electrodes 5. Since a circumferential speed of the roller 14 is about 130mm/sec, toner 16 on the roller 14 is conveyed under the electric field varied at 500Hz to be released from adhering force to the roller 14 and supplied under the apertures 6. A toner flow control unit controls a toner flow by a low control electrode.

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, 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.

However, according to this apparatus, the toner particles clog the apertures to deteriorate the recording quality, and the recording speed cannot be increased so much.

The applicant further studied, and as described in the application of Japanese Patent Application No. 4-254494, recording was carried out by arranging the carrier holding the toner and the recording electrode in contact with each other. An image recording apparatus that can greatly improve the characteristics is also proposed. According to this device,
Since the recording electrodes are not clogged, the image quality is remarkably improved, and it has become possible to reduce the size and cost of the image recording apparatus.

[0006]

However, in this conventional image forming apparatus, since the toner is attached to the carrier by the image force, van der Waals force, etc., the toner is supplied from the carrier at the time of recording. A high drive voltage is required to peel off and fly toward the support,
As a result, the driving element becomes expensive, and as a result, the entire device becomes expensive.

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 high-quality image at low cost by lowering the driving voltage. I am trying.

[0008]

In order to achieve this object, an image forming apparatus of the present invention comprises a toner flow control means provided with a toner flow control section, and a toner for supplying a charged toner to the toner flow control means. The toner carrier is composed of a carrier and a back electrode provided on the opposite side of the toner carrier to sandwich the toner flow control means, and controls the passage of the toner supplied by the toner carrier through the toner flow control unit to control the toner. An image forming apparatus for forming an image on a support arranged on the opposite side of a toner carrier from a flow control means, the direction of which is alternately different on the upstream side of the toner carrier in the toner supply direction. It is characterized in that it comprises means for forming an electric field.

[0009]

According to the image forming apparatus of the present invention having the above-mentioned structure, the toner is carried on the toner carrier and conveyed under the toner flow control means. Therefore, a voltage is applied to the toner flow controller according to the image signal. Before being conveyed under the electric field formed by the toner flow controller, the toner on the toner carrier is subjected to the force alternately on the toner flow control means side or the toner carrier side by the electric fields of different directions in advance. . Therefore, the toner on the toner carrier is
Since the toner flow is shaken and the adhesive force with the toner carrier is weakened, the toner flow control unit can control the toner flow with a relatively low control voltage.

[0010]

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

FIG. 1 is a diagram showing an outline of an image forming apparatus embodying the present invention, in which a rear electrode is provided with a gap of 0.5 mm above the aperture electrode body 1 as a toner flow control means. A cylindrical back electrode roller 22 is rotatably arranged on a casing (not shown) so that the support 20 inserted into the gap can be conveyed.

Below the aperture electrode body 1, along the longitudinal direction of the aperture electrode body 1, the toner supply device 1 is provided.
0 is disposed, and a transport roller 29 for transporting the support 20 between the aperture electrode body 1 and the back electrode roller 22 is rotatably arranged on the carry-in side of the aperture electrode body 1. Further, the fixing device 26 is installed at the destination of the support 20 conveyed by the back electrode roller 22.
Is provided.

Next, the respective components will be described in detail. In the toner supply device 10, the toner case 11 also serving as a housing of the entire device, the toner 16 stored in the toner case 11, and the supply roller 12 are provided. And a toner carrying roller 14 as a toner carrying member and a toner layer regulating blade 18. Here, the toner carrying roller 14 carries the toner 16 in layers.
The feeding roller 12 feeds the toner 16 to the toner carrying roller 14.

The supply roller 12 and the toner carrying roller 14 are rotatably supported in the toner case 11 in the direction of the arrow shown in FIG. Further, the toner layer regulating blade 18
Is for adjusting the amount of the toner 16 carried on the toner carrying roller 14 to be uniform on the roller surface and for uniformly charging the toner 16, and is pressed against the toner carrying roller 14.

As shown in FIG. 2, the aperture electrode body 1 comprises a polyimide insulating sheet 2 having a thickness of 25 μm, and a plurality of apertures 6 having a diameter of 100 μm penetrating the insulating sheet 2 arranged in a row at equal intervals. In addition, the control electrode 4 as a toner flow control unit is formed with a thickness of 1 μm on the peripheral edge of the opening of each aperture 6 on the upper surface side of the insulating sheet 2. Further, a plurality of alternating electric field electrodes 5 having a width of 30 μm are formed along the aperture 6 on the front side of the aperture 6 on the side opposite to the control electrode formation surface at intervals of 130 μm.

As shown in FIG. 3 in which the vicinity of the aperture shown in FIG. 1 is enlarged between each of the alternating electric field electrodes 5 and the toner carrying roller 14, +100 V and −10 are alternately provided.
A 0V DC power supply is connected.

The aperture electrode body 1 is arranged so that the alternating electric field electrode 5 is located upstream of the aperture 6 in the toner supply direction with the control electrode 4 facing the support body 20 as shown in FIG. It is arranged.

A control voltage application circuit 8 is connected between the control electrode 4 and the toner carrying roller 14.
The control voltage application circuit 8 is configured to apply a voltage of 0 V or +50 V to the control electrode 4 based on the image signal.

Further, a DC power source 24 is connected between the back electrode roller 22 and the toner carrying roller 14, and this DC power source applies a voltage of +1 kV to the back electrode roller 22. I'm supposed to get it.

Next, the operation of the image forming apparatus configured as described above will be described.

First, the toner 16 sent from the supply roller 12 is rubbed against the toner support roller 14 by the rotation of the toner support roller 14 and the supply roller 12 in the direction of the arrow shown in FIG. The toner is carried on the outer peripheral portion of the toner carrying roller 14. The carried toner 16 is thinned by the layer regulation blade 18 and then conveyed toward the aperture electrode body 1 by the rotation of the toner carrying roller 14.

The plurality of alternating electric field electrodes 5 are alternately +10.
Since voltages of 0 V and -100 V are applied, electric fields whose directions alternate with each other are formed between the alternating electric field electrode 5 and the toner carrying roller 14. Toner carrying roller 1
When the toner on 4 is located under the alternating electric field electrode 5, the toner is shaken by the alternating electric field in the direction of the aperture electrode body 1 and the direction of the toner carrying roller 14 by alternating force.
Since the peripheral speed of the toner carrying roller 14 is about 130 mm / s, the toner 16 on the toner carrying roller 14 is 5
By being transported under an electric field changing at 00 Hz, the adhesion force with the toner carrying roller 14 is released and the aperture 6 is released.
Supplied below.

On the other hand, the supporting body 20 is conveyed by the conveying roller 29 between the aperture electrode body 1 and the back electrode roller 22.

Here, in accordance with the image signal, the control voltage applying circuit 8 adds + to the control electrode 4 corresponding to the image portion.
A voltage of 50V is applied. As a result, lines of electric force are formed from the control electrode through the aperture and onto the toner carrying roller 14. The toner released from the adhesive force with the toner carrying roller 14 receives an electrostatic force from the electric field formed by the control electrode 4, passes through the aperture 6, and is drawn to the control electrode 4 side. The extracted toner 16 further flies toward the support 20 due to the electric field formed between the support 20 and the aperture electrode body 1 by the voltage applied to the back electrode 22, and the toner 16 on the support 20 rises. To form pixels.

A voltage of 0V is applied from the control voltage applying circuit 8 to the control electrode 4 corresponding to the non-image portion.
As a result, since no electric field is formed between the toner carrying roller 14 and the control electrode 4, the toner 16 on the toner carrying roller 14 does not receive the electrostatic force and therefore does not pass through the aperture 6.

Further, the support 20 is fed by one pixel in the direction perpendicular to the aperture row while the toner 16 forms one row of pixels on the surface thereof. Then, the toner image is formed on the entire surface of the support 20 by repeating the above process. Then, the formed toner image is fixed on the support 20 by the fixing device 26.

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 alternating electric field electrode 5 is arranged on the surface of the insulating sheet 2 on the toner supply side, but it may be arranged on the surface of the insulating sheet 2 facing the support 20 or the aperture. An insulating plate different from the insulating sheet 2 of the electrode body 1 may be provided, and the alternating electric field electrode 5 may be arranged there.

Although the control voltage of the aperture corresponding to the non-image portion is set to 0V in the above embodiment, it may be a negative voltage. In this case, an image with less fogging can be obtained. Further, although the control electrode is arranged on the side of the insulating sheet facing the support in the above embodiment, it may be on the toner supply side.

[0030]

As is apparent from the above description, according to the image forming apparatus of the present invention, the toner on the toner carrier is conveyed before being conveyed under the electric field formed by the toner flow control section. An electric field previously formed by the alternating electric field electrodes causes the toner flow control means side or the toner carrier side to be subjected to a force and shaken. Therefore, the toner flow control unit can control the toner flow with a relatively low control electrode. As a result, the driving voltage can be lowered, and as a result, it is possible to provide an image forming apparatus that is inexpensive and can form high-quality images.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing the main parts of an embodiment embodying the configuration of the image forming apparatus of the present invention.

FIG. 3 is a perspective view of an aperture electrode body used in the image forming apparatus of the present invention.

[Explanation of symbols]

 1 Aperture electrode body 2 Insulating sheet 4 Control electrode 5 Alternate electric field electrode 6 Aperture 8 Control voltage application circuit 14 Toner carrier roller 22 Back electrode roller

Claims (2)

[Claims] 1. A toner flow control means having a toner flow control section, a toner carrier for supplying the toner charged to the toner flow control means, and the toner carrier on the opposite side of the toner flow control means. It consists of a back electrode provided in
In an image forming apparatus for controlling the passage of toner supplied by a toner carrier through a toner flow controller to form an image on a support arranged on the opposite side of the toner carrier from the toner flow control means. An image forming apparatus comprising means for forming electric fields of different directions alternately on the upstream side of the toner carrier in the toner supply direction. 2. The image forming apparatus according to claim 1, wherein the toner flow control unit includes alternating electric field electrodes capable of forming electric fields of different directions alternately with the toner carrier.