JP2518552B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus using powder toner.

(Prior Art) For word processors, facsimile machines, computers and the like, an image forming method using an ink jet printer is known.

Ink jet printers are typical of so-called non-impact printers.
By applying pressure while applying ultrasonic vibration by a piezoelectric element or the like, the liquid ink is ejected from an ink nozzle within a predetermined electric field, and the ink particles are controlled by the electric field to adhere to recording paper, thereby forming a recorded image. Is formed on the recording paper. In such an ink jet printer system,
There is an advantage that no noise is generated when forming an image and a clear image can be formed. On the other hand, in order to control the speed at which ink permeates the recording paper, it is necessary to use special paper that has undergone surface treatment, etc., and since ink is supplied from the nozzle, the nozzle has foreign matter inside the ink. There is a problem that it is easily clogged due to factors such as.

In order to solve the problem of such an ink jet printer, an image forming apparatus using powder toner as an image recording medium is disclosed in, for example, Japanese Patent Laid-Open No. 62-263962. This image forming apparatus is provided with toner control means for controlling powder toner particles to pass through a pinhole-shaped toner passage hole by electrostatic attraction generated in response to an image output signal. By the toner control means,
A predetermined recording image is formed on the recording paper by selectively feeding the toner particles onto the recording paper. In such an apparatus, plain paper which has not been subjected to surface treatment or the like can be used as recording paper, and since fine particle powder toner is used, clogging of toner in each toner passage hole is suppressed. .

The toner control means for controlling the powder toner is provided with an insulating substrate provided with a large number of pinhole-shaped toner passage holes, and the insulation substrate interposed so as to form an electric field in each toner passage hole. And a pair of electrodes provided. Each pair of electrodes is provided with a through hole similar to each toner passage hole, and is attached to one surface of the insulating substrate with each through hole aligned with each toner passage hole. ing.

Then, by applying a predetermined voltage between both electrodes to form an electric field in a predetermined direction in the toner passage hole, the toner particles pass through the toner passage hole. To prevent the toner particles from passing through the toner passage holes, a predetermined voltage is applied between the electrodes so that an electric field in the opposite direction to that when toner particles are passed is formed in the toner passage holes. To be done.

(Problems to be Solved by the Invention) However, the lump of toner supplied into the toner passage hole cannot be sufficiently crushed only by forming the electric field in the predetermined direction in the toner passage hole as described above. However, the voltage applied between the pair of electrodes must be set to a large value, so that there is a limit in improving the toner passing efficiency and increasing the image density.

In addition, there is a limit in making the toner drop amount uniform.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide an image forming apparatus that can improve the toner passing efficiency through the toner passage holes and can even out the toner drop amount.

(Means for Solving the Problems) The image forming apparatus of the present invention includes a toner control unit having a pair of electrodes for forming an electric field in the toner passage hole on both surfaces of a substrate having the toner passage hole, and the toner control unit. A supporting member for supporting the control means, and an image information generating means for setting a predetermined potential between the pair of electrodes so as to form an electric field in the toner passing direction in the toner passing hole in accordance with the image information. Mounted between one end of the toner control means and the supporting member at the other end of the toner control means and an ultrasonic vibration generation means for applying ultrasonic vibration to the toner control means. And an elastic member that absorbs the ultrasonic vibration applied to one side of the toner control means by the ultrasonic vibration generating means and propagated to the other end of the toner control means, thereby achieving the above object. To be done.

(Operation) In the above configuration, when an AC voltage is applied to the ultrasonic vibration generating means, the ultrasonic vibration generating means generates ultrasonic vibration, and the generated vibration is transmitted to the toner control means to decompose the toner into particles. In addition, since kinetic energy is applied to the toner particles, the toner can efficiently pass through the toner passage holes due to the cooperation with the electric field.

Further, at this time, the generated vibration propagates on the toner control unit from one side portion to the other side end portion. However, since the elastic member attached to the other side end portion absorbs the vibration, the vibration wave is not reflected. Does not happen. That is, the position of the elastic member is vibrationally at the open end. Therefore, standing waves in a stagnant state in which waves interfere with each other do not occur, and the intensity of ultrasonic vibration does not concentrate at a specific position, resulting in a substantially uniform state. Therefore, the toner drop amount can be made uniform.

(Example) Hereinafter, the Example of this invention is described.

As shown in FIG. 1, the image forming apparatus of the present invention has a toner container 10 in which toner is sequentially replenished from a toner hopper or the like. An opening 11 is provided at the bottom of the toner container 10.
Is provided, and the upper portion of the toner supply roller 12, which is toner supply means, is fitted into the opening 11. As the toner supply roller 12, a sponge roller is used in which a sponge layer 14, which is an elastic insulator, is attached to the outer peripheral surface of the roller portion 13. Below the toner supply roller 12, a toner control means 20 is arranged in a horizontal state in the vicinity of the toner supply roller 12. An image signal is given to the toner control means 20 from the image information generation means 40. The image information generating means 40 operates in response to a signal from a device body such as a word processor, a facsimile, a computer or the like, and generates an electric signal corresponding to the image information. According to this electric signal, the powder toner charged from the toner supply roller 12 to a predetermined polarity is transferred to the recording paper 60 arranged below the toner control means 20 by the toner control means 20. Supply and non-supply are controlled. As a result, a predetermined toner image is formed on the recording paper 60. The toner control means 20 is a toner supply roller.
It may be pressed against 12.

The toner control means 20 is supported by a support member 70, and an ultrasonic vibration generating means 30 for applying ultrasonic vibration is provided on a portion of the upper surface of the toner control means 20 on the right side in the drawing. On the other hand, the ultrasonic vibration generating means of the toner control means 20
An elastic member 31 made of rubber or the like is mounted between the support member 70 and an end position on the side opposite to the arrangement position of 30. A base electrode 50 is provided below the toner control unit 20 so as to face the toner control unit 20.

A recording paper 60 on which a toner image is formed is placed on the base electrode 50. The base electrode 50 may be moved in the direction indicated by the arrow A together with the recording paper 60 to be placed, or the base electrode 50 may be fixed and only the recording paper 60 may be moved by a predetermined recording paper conveying means. You may allow it.
When the toner control unit 20 forms a predetermined toner image on the recording paper 60, the recording paper 60 is conveyed to a predetermined fixing device (not shown), and the toner image is recorded by the fixing device.
It is fixed at 60.

As shown in FIG. 2, the toner control means 20 to which, for example, negatively charged toner is supplied by the toner supply roller 12, is a horizontal conductive substrate 21 having a pinhole-shaped toner passage hole 22 formed therein, and the horizontal conductive substrate 21. It has a conductive upper mesh electrode 23 provided on the upper surface of the conductive substrate 21. Conductive substrate 21
A lower mesh electrode 25 is provided on the lower surface of each of the toner passage holes 22 via an insulating member 24. The upper mesh electrode 23 is in a state of covering the upper opening of the toner passage hole 22, and is in a state of being close to the toner supply roller 12 or in pressure contact therewith. The ultrasonic wave generation means 30 provided in the toner control means 20 is attached to the conductive substrate 21 so as to apply ultrasonic vibration to at least the upper mesh electrode 23. If possible, the ultrasonic vibration generating means 30 is adapted to apply ultrasonic vibration only to the upper mesh electrode 23.

The ultrasonic vibration generating means 30 is preferably one that generates a sine wave, a square wave, a triangular wave or the like at a resonance frequency in the range of 20 KHz to 1 MHz, and a piezoelectric element such as PZT is used.

The conductive substrate 21 is grounded, and the conductive upper mesh electrode 23 is grounded through the conductive substrate.

An electric signal from the image information generating means 40 is applied to the lower mesh electrode 25. The image information generating means 40,
An electric signal is generated based on the image information, and for example, a voltage of + 100V is applied to the lower mesh electrode 25 as an image forming signal to form an image, and a voltage of -100V is applied to the lower mesh electrode as an image non-forming signal that does not form an image. The electrode 25. Therefore, when a voltage of + 100V is applied to the lower mesh electrode 25 by the image forming signal from the image information generating means 40, an electric field from the lower mesh electrode 25 to the grounded upper mesh electrode 23 is transferred to the toner passage hole. Formed within 22. On the contrary, when a voltage of -100V is applied to the lower mesh electrode 25 by the image non-forming signal from the image information generating means 30, the upper mesh electrode 23 to the lower mesh electrode
An electric field toward 25 is formed in the toner passage hole.

 The operation of the image forming apparatus having such a configuration will be described.

By rotating the toner supply roller 12, the toner container 10
The negatively charged toner in the inside is supplied onto the upper mesh electrode 23 in the toner control means 20. Upper mesh electrode
Since the ultrasonic vibration generating means 30 applies vibration of a constant amplitude to the 23, the lumps of toner supplied onto the upper mesh electrode 23 are appropriately crushed and the upper mesh electrode 25 Pass through.

The toner that has passed through the upper mesh electrode 23 is controlled according to the image signal given to the lower mesh electrode 25,
Drop onto recording paper 60 or upper mesh electrode 23
Return to top.

For example, when a voltage of + 100V is applied to the lower mesh electrode 25 by the image signal generating means 40, an electric field from the lower mesh electrode 25 on the lower side to the upper mesh electrode 23 on the upper side is generated in the toner passage hole 22. Occurs. Due to this electric field, the toner particles that have been negatively charged in advance are attracted to the lower mesh electrode 25, pass through the lower mesh electrode 25, and fall onto the recording paper 60 on the base electrode 50. Since a positive bias voltage is applied to the base electrode 50 with respect to the upper mesh electrode 23, the toner passing through the toner passage hole 22 is attracted to the base electrode 50,
The fall is promoted. The bias voltage applied to the base electrode 50 is sufficiently larger than the electric signal applied to the lower mesh electrode 25, and is 30 in the case of negatively charged toner.
The range is from 0 to 1000V. If the bias voltage is less than 300V, the toner drop position may vary and the image may be disturbed. On the other hand, if the bias voltage is higher than 1000V, discharge may occur.

When an image non-forming signal is given by the image information generating means 50 and a voltage of -100V is applied to the lower mesh electrode 25, the upper mesh electrode on the upper side is provided in the toner passage hole 22.
An electric field is formed from 23 toward the lower lower mesh electrode 25, and the negatively charged toner is returned to the upper mesh electrode 23.

In this way, a predetermined toner image is formed on the recording paper 60.

In addition, as described above, when the elastic member 31 is attached to the end portion of the toner control unit 20 opposite to the position where the ultrasonic vibration generation unit 30 is arranged, the toner control unit 20 is placed above the ultrasonic vibration generation unit 30. Since the vibration propagating from the arranged position to the position of the elastic member 31 is absorbed at the position of the elastic member 31, a reflected wave heading to the position of the ultrasonic vibration generating means 30 is not generated. Therefore, stagnant standing waves in which the waves interfere with each other do not occur on the toner control unit 20. Therefore, the intensity of ultrasonic vibrations can be made substantially uniform without being concentrated at a specific position, so that the toner drop amount can be eventually made uniform.

Although the upper mesh electrode 23 is grounded in the above embodiment, a voltage having a polarity opposite to that of the voltage applied to the lower mesh electrode 25 is set based on the signal emitted from the image information generating means 40. You may make it apply.

In the present invention, it is desirable to use a toner having a relatively small average particle diameter of 5 to 20 μm, and an image with excellent resolution can be formed by the small diameter toner.

The conductive substrate 21 has a thickness of 0.01 to 1 mm, and the toner passage hole 22 provided in the conductive substrate 21 has a thickness of 0.1 to 1 mm.
It is said. The mesh size of the upper mesh electrode 23 is 50-300μ
The mesh size of the lower mesh electrode 25 is preferably larger than that of the upper mesh electrode 23.

Upper mesh electrode 23 and lower mesh electrode 25
Is usually nickel, stainless steel, aluminum, copper,
A Tyler mesh, an etching mesh or the like formed of a metal such as silver or a conductive resin is adopted.

The distance between the toner control means 20 and the recording paper 60 varies depending on the magnitude of the applied voltage applied from the image information generating means 40, but is usually in the range of 0.3 to 2.5 mm.

In this embodiment, a sponge roller is used as the toner supply roller 12. The sponge roller effectively crushes the aggregated toner in the toner container 10 as the sponge roller rotates,
Since the toner is held in the joints on the surface in a substantially uniform state, the toner control unit 20 is always supplied with a constant amount of toner.

Although the upper mesh electrode 23 on the toner supply side is grounded and the image signal is given to the lower mesh electrode 25 in the above embodiment, the upper mesh electrode 23 on the toner supply side is made conductive. An image signal may be given to the upper mesh electrode 23 by disposing the lower mesh electrode 25 grounded on the upper surface of the conductive substrate 21 via an insulating member and directly attached to the conductive substrate 21. .

(Effects of the Invention) According to the present invention described above, since the toner is decomposed into particles by ultrasonic vibration, the lump of toner is reliably crushed at the entrance of the toner passage hole.

Further, at this time, the generated vibration propagates on the toner control unit from one side portion to the other side end portion, but since the elastic body attached to the other side end portion absorbs the vibration, the vibration wave is not reflected. Does not happen. Therefore, standing waves in a stagnant state in which waves interfere with each other do not occur, and the intensity of ultrasonic vibration does not concentrate at a specific position, resulting in a substantially uniform state. Therefore, the toner drop amount can be made uniform, and the image accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a drawing showing an embodiment of an image forming apparatus of the present invention, and FIG. 2 is a sectional view of the main part thereof. 20 ... Toner control means, 21 ... Conductive substrate, 22 ... Toner passage hole, 23 ... Upper mesh electrode, 25 ... Lower mesh electrode, 30 ... Ultrasonic vibration generating means, 31 ... Elasticity Material, 70 ... Support material.

Claims (1)

(57) [Claims] 1. A substrate having a toner communication hole formed on both sides thereof,
A toner control unit having a pair of electrodes forming an electric field in the toner passage hole, a support member supporting the toner control unit, and an electric field in a direction in which the toner passes through the toner passage hole according to image information. Image information generating means for setting a predetermined potential between the pair of electrodes so as to form, and ultrasonic vibration generating means provided on one side of the toner control means for applying ultrasonic vibration to the toner control means. At the other end of the toner control means, it is mounted between the supporting member and the ultrasonic vibration generating means and applied to one side of the toner control means and propagated to the other end. An image forming apparatus comprising: an elastic member that absorbs ultrasonic vibrations.