JPH05185643A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To provide an inexpensive small-sized image forming apparatus not requiring a high voltage power supply or AC power supply and capable of forming a sharp image by mounting a toner feed belt arranged so as to be subjected to friction vibration at the part where a toner supply means is opposed to an aperture. CONSTITUTION:A toner supply device 20 is constituted so that the belt 24 held between drive and supply rollers 22, 23 comes into contact with a rod shaped support 25 under pressure. Toner 26 is rubbed with the belt 24 wound around the drive roller 22 from the supply roller 23 and positively charged to be supported on the belt 24. The supported toner 26 is formed into a thin layer by a layer prescribing blade 27 to be fed to the vicinity of the support 25 by the drive roller 22. Since the belt 24 is in contact with the support 25 under pressure in this process, the belt 24 repeats stop and advance little by little by the stationary friction force of the support 25 and the belt 24 and the elastic recovery force due to the elongation of a belt advance part 28. By repeating the stop and advance of the belt, the surface opposed to an aperture of the belt 24 is vibrated and the toner 26 on the belt is released from the belt to be supplied to the scanning electrode 4 of an aperture electrode 1.

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 obtaining an image on a support by controlling the passage of an aperture of toner particles by applying an image signal to an electrode having an aperture has been disclosed in USP368.
Proposed in 9935. In this proposal, it is composed of a reference electrode that is continuous on one side with a layer of an insulator sandwiched between it and a plurality of control electrodes that are insulated from each other on the other side. An aperture electrode body having at least one row of apertures, means for selectively applying a potential between the control electrode and the reference electrode, and the applied potential modulates the flow of toner particles through the aperture. It is composed of means for projecting electrically charged particles and means for moving the support with respect to the aperture electrode body to position the support in the particle flow path.

In this system, as means for supplying charged toner particles to the vicinity of the aperture, Japanese Patent Laid-Open No. 62-248.
In Japanese Patent No. 662, a method of carrying toner on the surface of a toner carrying roller and carrying the toner to the vicinity of the aperture by the rotation of the roller is disclosed in Japanese Patent Laid-Open No. 58-44457. In order to convey the charged toner in the form of a cloud by applying a voltage, Japanese Unexamined Patent Publication (Kokai) No. 58-114974 has proposed a method in which toner particles are placed on an air stream and conveyed.

[0004]

However, as described above, the one using the carrying roller for supplying the toner particles to the vicinity of the aperture has a force such as a mirror image force or a van der Waals force that the toner adheres to the carrying roller. Is relatively large. Therefore, a strong electric field is required to peel off the toner from the carrying roller and pass through the aperture, and therefore a high voltage power supply is required.

Further, a device utilizing an alternating electric field requires a high-voltage AC power supply therefor, and the alternating electric field disturbs the control electric field for controlling the passage of the toner aperture, so that the apparatus is expensive and the image becomes unclear. There is.

A device utilizing an air flow has a drawback that a device such as a compressor is required to generate the air flow and the image forming apparatus as a whole is complicated and expensive.

The present invention has been made in order to solve the above-mentioned problems, and is inexpensive by using a toner supply means that does not require an expensive device such as a high-voltage AC power supply or a compressor and whose aperture passage control is easy. It is an object to provide a compact image forming apparatus.

[0008]

In order to achieve this object, the image forming apparatus of the present invention is provided with a toner carrying belt which is arranged so that the toner supply means frictionally vibrates at the portion facing the aperture.

[0009]

According to the image forming apparatus of the present invention having the above structure, the toner carried on the toner conveying belt is
In the vicinity of the aperture, frictional vibration of the belt releases the adhesive force such as van der Waals force and supplies it to the aperture.

[0010]

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 back electrode roller 32 is rotatably arranged on an upper side of the aperture electrode body 1 in an enclosure (not shown) so as to rotate and convey the support body 31.
The back electrode roller 32 is connected to a positive DC power source 33. A toner supply device 20 is arranged below the aperture electrode body 1.

The toner supply device 20 is constructed as follows. Along with the toner 26 in the toner case 21, the drive roller 22 and the zinc-plated diameter 3 mm
Steel rod-shaped supports 25 are arranged in parallel with each other, and a 200 μm-thick silicon rubber belt 24 is wound around the belt-shaped supports 25 under tension, so that the belt 24 is pressed against the rod-shaped supports 25.

The belt 24 is sandwiched by a supply roller 23 arranged in parallel with the driving roller 22. The toner regulating blade 27 is arranged so as to come into pressure contact with the belt on the drive roller 22.

As shown in detail in FIG. 2, the aperture electrode body 1 includes a plurality of data electrodes 3 on the upper side of an insulating sheet 2 made of polyimide, and eight scan electrodes 4 extending in the width direction on the lower side. The apertures 6 are arranged in a grid pattern and penetrate the three layers at the positions where the data electrodes 3 and the scan electrodes 4 intersect. The data electrode 3 and the scan electrode 4 are connected to a control voltage drive circuit 8 that generates an electric field in the aperture according to an image signal.

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

By the rotation of the drive roller 22 and the supply roller 23 in the direction of the arrow, the toner 26 is rubbed from the supply roller 23 to the belt 24 wound around the drive roller 22, is negatively charged, and is carried on the belt 24. It The carried toner 26 is thinned by the layer regulation blade 27, and is supported by the rotation of the driving roller 22.
It is transported toward the neighborhood. In this process, the belt 24 is pressed against the support 25, so that the frictional force of the belt 24 causes the belt 24 to stop and advance in small increments. That is, at first, the belt stopped on the support against the driving force of the driving roller 22 due to the static frictional force between the support and the back surface of the belt.
It grows at 8. When the elastic restoring force of the belt advancing portion 28 exceeds the static frictional force, the belt advances. When the extension of the belt advancing portion 28 is restored, the belt on the support stops again due to friction. By repeating this, the surface facing the aperture vibrates and the toner carried on the surface is released from the adhesive force with the belt and is supplied to the scan electrode side of the aperture electrode body 1.

Here, + 50V is applied to one scan electrode by the electrode drive circuit 8 and 250V is applied to the other scan electrode.
+ 200V or 0V is applied to each data electrode 3 in accordance with the image signal in the state of being kept at.

Among the apertures in which + 50V is applied to the scan electrode, those in which a voltage of 200V is applied to the data electrode are negatively charged because an electric force line extending from the data electrode surface to the scan electrode surface is formed. The toner is extracted from the scan electrode surface to the data electrode surface, and further, the toner flies and is held on the support 31 by the flying electric field formed by the back electrode roller 32 to form an image portion. Electric lines of force from the scan electrode surface to the data electrode surface are formed in the aperture where the voltage of 0V is applied to the data electrode, and the passage of the negatively charged toner through the aperture is suppressed.

The scan electrodes are sequentially activated by the electrode drive circuit 8, that is, +50 V is applied, and +2 is applied to the data electrode of the aperture on the scan electrode in accordance with the image signal.
An image is formed line by line by applying 00V or 0V.

When the scan of the scan electrode has completed one cycle, the support is moved by the dot interval and the above process is repeated. A toner image is formed on the entire surface of the support by the time the support is completely conveyed.

[0021]

As is apparent from the above description, according to the image forming apparatus of the present invention, since a high electric field is not used in the toner supplying means, a high voltage power source is not necessary. Since the AC electric field is not used, the control electric field is not disturbed and an unclear image is not formed. Further, there is no need for a power source for generating an AC electric field. Therefore, it is possible to provide an inexpensive, small-sized image forming apparatus having a clear formed image.

[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 Sheet 3 Data Electrode 4 Scan Electrode 6 Aperture 24 Belt 25 Support 26 Toner 31 Support 32 Back Electrode Roller

Claims (1)

[Claims] 1. An image signal is applied to an electrode having an aperture to control the passage of charged toner through the aperture, and an image is formed on a support provided on the opposite side of the electrode with an aperture from the toner supply source. In the image forming apparatus for forming the image forming apparatus, the toner supplying unit includes a toner conveying belt arranged so as to frictionally vibrate at a portion facing the aperture.