JPH0531943A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To provide an image forming apparatus forming a sharp image without being affected by the kind of support. CONSTITUTION:A control means not shown in a drawing controls the voltage of a high voltage power supply 12 on the basis of the data of the kind of a support from a sensor 57 and the applied voltage of an opposed electrode 11 is altered. For example, in the case of a thick support 10, slightly low voltage is applied and, in the case of a thin support 10, slightly high voltage is applied. Therefore, the flight electric field formed by the opposed electrode 11 becomes constant regardless of the kind of the support 10.

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 recording apparatus for controlling the passage of toner particles through an aperture to obtain an image on a support by applying an image signal to an electrode having an aperture has been proposed in US Pat. No. 3,689,935. ing. In this proposal, a reference electrode that is continuous on one side across an insulator layer,
An aperture electrode body having a plurality of control electrodes insulated from each other on the other surface, and having at least one row of apertures penetrating three layers for each of the insulated control electrodes, and a control electrode. Means for selectively applying a potential to the reference electrode, means for projecting charged particles so as to modulate the flow of toner particles through the aperture by the applied potential, and the support and the aperture electrode body To position the support in the particle flow path.

[0003]

However, in the conventional device, when outputting to a cardboard, for example, as a support, the support has a higher relative permittivity than air, but the voltage applied to the counter electrode is constant. Therefore, the electric field becomes strong, and the toner excessively flies to the support. As a result, it becomes dark and a clear image cannot be formed.

The present invention has been made to solve the above-mentioned problems, and is not affected by the type of support.
An object of the present invention is to provide an image forming apparatus that forms a clear image.

[0005]

To achieve this object, the image forming apparatus of the present invention is an aperture electrode having an opening provided with a carrier carrying toner and an insulating layer sandwiched between two electrodes. And a counter electrode provided so as to face the aperture electrode across a support, and carry charged toner to the vicinity of the aperture electrode by a carrier,
An image forming apparatus that forms an image by passing through the opening and flying toward the counter electrode and adsorbing to the support by modulating the aperture electrode to detect the type of the support. It has a detection means and a control means for controlling the voltage of the counter electrode based on the information from the detection means.

[0006]

According to the present invention having the above construction, the type of the support is detected by the detection means, and the voltage of the counter electrode is controlled by the control means based on this information to form an image on the support.

[0007]

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 image forming apparatus 100 according to an embodiment of the present invention. Aperture electrode body 1
2 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, and an aperture 6 penetrating the reference electrode 3, the insulating layer 2 and the control electrode 4, as shown in FIG. A large number of rows are formed in the same width as the support. In FIG. 1, on the left side of the image forming apparatus 100, a cassette 50 that accommodates the supports 10, a half-moon roller 51 that supplies the supports 10 one by one, and a support supply roller that sends the supports 10 to a downstream portion. 52 and chute 53 are arranged.

On the downstream side, on the control electrode side of the aperture electrode body 1, the support carrier roller 14, the sensor 57, and
A counter electrode 11 is disposed in contact with the back surface of the support body 10, and each control electrode 4 is connected to a control voltage drive circuit 8 that generates a voltage according to an image signal. The counter electrode 11 is connected to a negative high voltage power supply 12.

The sensor 57 is a transmissive photosensor. The photodiode 57 receives the amount of light emitted from the LED 57a that passes through the support 10, and the photodiode 5
By detecting the voltage generated by 7b, the support 1
The type of 0 thickness and material is detected.

On the reference electrode side of the aperture electrode body 1, a toner carrying belt 26 is wound between the driving roller 20 and the backup roller 24, and the carrying belt has an elliptical cross section on the back side of the surface facing the aperture electrode body. The cam roller 27 is provided with the static elimination brush 31 on the upstream side thereof. These are stored in the toner case 21 together with the toner 22 accumulated in the vicinity of the supply roller 23, and a carrying roller 30 that is in contact with the supply roller 23 and has a clearance of 0.1 to 0.4 mm with respect to the toner transport belt 26. Has been. The supply roller 23 has a sponge or the like, and the supporting roller 30 has a resin surface.

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

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

The support 10 housed in the cassette 50 is
Half moon roller 51 feeds out one by one and shoots 5
3 is guided by the supporting member feeding roller 52 and is conveyed to the supporting member conveying roller 14. When the sensor 57 detects the tip and type of the support 10, the drive roller 20
The toner transport belt 26 rotates between the backup roller 24 and the drive roller 20 by the rotation in the direction of the arrow, and the toner 22 is rubbed by the carrying roller 30 and positively charged by the toner by the rotation of the supply roller 23 in the direction of the arrow. The carrier belt 26 is carried by electrostatic coating using a high voltage power source.

The carried toner is conveyed toward the surface facing the aperture electrode, and on the upstream side of this position, the conveying belt 26 is removed from the back side of the conveying belt 26 by the static elimination brush 31.
Is discharged. Since the cam roller 27 is rotating at the position of the surface 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 vibration acceleration of the conveyor belt 26, and is released from the image force, the van der Waals force, and the adhesion force such as the electrostatic force with the conveyor belt 26.

On the other hand, at this time, if a negative voltage is applied to the control electrode 4 in accordance with an image signal from a storage means (not shown),
Electric force lines from the back surface of the aperture 6 to the front surface are formed in the aperture 6 of the applied control electrode 4, and the positively charged toner 22 is extracted from the back surface of the aperture 6 to the front surface. Flies on the support by the flying electric field formed by the counter electrode 11 and is held, thereby forming an image portion.

At this time, the control means (not shown) controls the voltage of the high-voltage power source 12 and changes the voltage applied to the counter electrode 11 based on the information of the type of the support from the sensor 57. For example, a lower voltage is applied to the thick support 10 and a higher voltage is applied to the thin support 10. Therefore, the flying electric field formed by the counter electrode 11 is constant regardless of the type of the support 10, and a clear image can always be output.

The flying electric field by the counter electrode 11 is shielded 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, or the inside of the aperture 6 is shielded. The toner 2 is formed by forming a line of electric force from the front surface to the reference electrode 3 on the back surface.
Suppress the passage of the aperture 6 of 2. By repeating this process while transporting the support 10, a toner image is formed on the entire surface of the support 10.

The support on which the toner image is formed is the fixing device 1.
After passing through 3, the image is fixed on the support 10. Further, it is guided by the chute 54 and discharged onto the tray 56 by the discharge roller 55.

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

[0021]

As is clear from the above description,
According to the present invention, the flying electric field formed by the counter electrode is constant regardless of the type of the support, and a clear image can always be output.

[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 body 2 Insulating layer 3 Reference electrode 4 Control electrode 6 Aperture 8 Control voltage drive circuit 10 Support 11 Counter electrode 12 High voltage power supply 22 Toner 23 Supply roller 24 Backup roller 26 Toner transport belt 57 Sensor

Claims (1)

Claim: What is claimed is: 1. A carrier carrying toner, an insulating layer sandwiched between two electrodes, an aperture electrode having an opening, and a support sandwiched between the carrier and the aperture electrode. The charged toner is carried by the carrier up to the vicinity of the aperture electrode, and modulation is controlled by the aperture electrode to let the toner fly toward the counter electrode through the opening. An image forming apparatus for forming an image by adsorbing onto a support has a detection means for detecting the type of the support, and a control means for controlling the voltage of the counter electrode based on information from the detection means. An image forming apparatus characterized by the above.