JPH05229170A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent effectively accumulation of toner particles onto an aperture electrode, by a method wherein frequency of an oscillation incident into an aperture electrode is modulated, through which a standing wave by synthesization of an incident wave and reflecting wave is prevented from exciting. CONSTITUTION:An exciting body 2 exciting a vibration to an aperture electrode is joined electrically to a driving circuit 3 and the driving circuit 3 is constituted of a modulation control signal oscillator and a voltage control oscillator applying oscillated frequency to the exciting body 2 by modulating the same in accordance with a control signal to be put out from this modulation control signal oscillator. Hereupon, when an oscillation obtained by modulating oscillation frequency by an electric signal to be applied from a voltage control oscillator is excited onto the aperture electrode 1 from the exciting body 2, since an incident wave from the exciting body 2 and a reflected wave which is reflected by a reflector 20 do not interfere with each other, a standing wave by overlapping both of them is prevented from generating on the aperture electrode 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus for forming an image on a recording medium by directly controlling the modulation of toner by an aperture electrode. ..

[0002]

2. Description of the Related Art An image forming apparatus of this type has been reported in, for example, US Pat. No. 3,689,935. This image forming apparatus includes a toner crowder, an aperture electrode,
It is composed of a counter electrode. The toner clouder is a means for generating a cloud of charged toner and supplying the toner cloud to the vicinity of the aperture electrode.

The aperture electrode is a control means for modulating and controlling the flow of toner from the toner cloud.
An insulating layer having a large number of apertures or openings, a first electrode layer provided on one surface of the insulating layer, and a first electrode layer provided on the other surface of the insulating layer, independent of each of the plurality of apertures. And a large number of second electrode layers provided in. Further, the counter electrode attracts and holds a recording medium such as paper, and is arranged so as to face the aperture electrode.

In the image forming apparatus configured as described above, the toner flow supplied by the toner crowder is controlled by an electric signal applied to the aperture electrode and the counter electrode to form an image on a recording medium such as paper. Is formed.

When an image is formed by this image forming apparatus, there is a problem that holes are clogged with toner in the aperture portion of the aperture electrode. That is, for example, in order to obtain a recording density of 240 DPI, the dot size is 100 μm at the maximum, so it is necessary to reduce the inner diameter of the aperture of the aperture electrode to about 50 μm at the maximum. When the inner diameter of the aperture is reduced in this way, toner particles are deposited on the aperture electrode due to image force and the like, and as a result, the aperture electrode is clogged with the toner particles, and it is difficult to always obtain a stable image output. There was a problem.

Therefore, the present applicant has filed Japanese Patent Application No. 2-29111.
As described in the specification and drawings attached to the application of No. 6, it was proposed to excite a traveling wave on the aperture electrode to prevent the deposition of toner particles. In this method, a vibration acceleration generated by a traveling wave excited on the aperture electrode is applied to the toner particles, so that the toner particles to be deposited on the aperture electrode have a repulsive force larger than the image force or the like that causes the deposition. Is a method for preventing the deposition of toner particles.

In the image forming apparatus as described above, the shape of the aperture electrode is generally a rectangular flat plate. Therefore, in order to excite a traveling wave on this aperture electrode, the aperture electrode is arranged in the aperture row direction. An exciter is provided at one end, and a reflected wave absorber is installed at the other end to absorb and consume the energy of the vibration of the traveling wave propagating on the aperture electrode to prevent the generation of the reflected wave. Only had to excite.

[0008]

However, when the traveling wave is excited by the above-mentioned method, in order to make the amplitude distribution of the traveling wave in the traveling direction substantially constant, the vibration input from the exciter is The energy had to be completely consumed by the reflected wave absorber, but it is very difficult to completely eliminate the reflected wave. Therefore, by superimposing the incident wave incident from the exciter and the reflected wave from the reflected wave absorber,
A standing wave is excited on the aperture electrode, and sufficient vibration acceleration cannot be applied to the toner particles in the vicinity of the node of the standing wave, resulting in the problem that the toner particles are deposited in the vicinity of the node.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent excitation of a standing wave due to superposition of an incident wave and a reflected wave so that the standing wave can be formed on the aperture electrode. An object of the present invention is to provide an image forming apparatus that can effectively prevent the accumulation of toner particles.

[0010]

In order to achieve this object, an image forming apparatus of the present invention comprises an aperture electrode for modulating and controlling charged toner, and an exciter for exciting vibration in the aperture electrode. The vibration excited by the exciter on the aperture electrode is a vibration whose frequency is modulated.

[0011]

In the image forming apparatus of the present invention having the above construction, the value of the vibration frequency of the incident wave and the reflected wave, the difference between them, and the phase difference between the two change with time, so that the incident wave and the reflected wave Wave interference does not occur, and as a result, standing wave excitation due to superposition of the two can be prevented.

[0012]

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

In FIG. 5, the toner jet recording apparatus 1
00 is composed of a recording unit 101 and a heat fixing unit 102. On the side of the toner jet recording apparatus 100,
An insertion port 117 and an ejection port 118 are provided. In the recording unit 101, an image or the like is recorded on the medium P such as plain paper that has entered through the insertion slot 117. Then, in the heat fixing unit 102, the image or the like on this medium is fixed. Further, the medium P is sent to the ejection port 118 via the guide 115.

The recording unit 101 comprises a rotatable brush roller 103, an aperture electrode 1 and a counter electrode 112.

Around the brush roller 103, a supply roller 104 and a scraping member 110, which are rotatable according to the rotating direction of the brush roller 103, are provided in contact with the brush roller 103, respectively. A supply blade 111 is provided in contact with the supply roller 104. On the supply blade 111, the toner T
Is stored. Then, the toner T is forcibly supplied to the supply roller 104 by the supply blade 111. Supply roller 104 and supply blade 111
Is covered by the case K.

The aperture electrode 1 is provided above the brush roller 103.

Next, the structure of the aperture electrode will be described with reference to FIG. In FIG. 1, the aperture electrode 1
Is composed of a large number of apertures 11, an insulating layer 106, a reference electrode layer 107, and a large number of control electrode layers 108. Then, one end of the aperture electrode 1 is provided with an exciter 2 that excites vibrations in the aperture electrode 1, and the other end is attached with a reflector 20 that reflects the vibration incident from the exciter 2. It is set up. Further, the excitation body 2 is formed of a laminated piezoelectric body, and its shape and dimension are such that the resonance frequency of the lowest Y-direction stretching vibration of the excitation body 2 is greater than the frequency of the vibration excited on the aperture electrode 1. It is adjusted to be sufficiently high.

A method of frequency-modulating a signal applied to the excitation body 2 formed of a laminated piezoelectric material will be described with reference to FIGS. 2 to 4. The exciter 2 is electrically connected to the drive circuit 3 and the drive circuit 3
As shown in FIG. 2, a voltage-controlled oscillator 31 that generates an AC electric signal, a modulation control signal oscillator 32 that modulates and controls the frequency of the electric signal output from the voltage-controlled oscillator 31, and the voltage-controlled oscillator 31. It is composed of an amplifier 33 that amplifies the electric signal output from.

The voltage-controlled oscillator 31 is an oscillator in which the frequency of the output AC signal is modulated and controlled by the voltage of the control signal applied from the modulation control signal oscillator 32. Therefore, when the control signal applied from the modulation control signal oscillator 32 to the voltage controlled oscillator 31 is a sinusoidal signal as shown in FIG. 3, the drive signal applied from the drive circuit 3 to the exciter 2 is shown in FIG. As shown in, the signal becomes a so-called frequency-modulated signal whose frequency changes with time.

The resonance frequency of the lowest Y-direction stretching vibration of the exciter 2 in such a way that it expands and contracts following the electric signal applied from the drive circuit 3 is greater than the frequency of the vibration excited on the aperture electrode 1. Since the shape and size are adjusted so as to be sufficiently high, when a frequency-modulated signal as shown in FIG. 4 is applied to the exciter 2, the frequency difference between the incident wave and the reflected wave excited in the aperture electrode 1 and Since the phase difference constantly changes, the two do not interfere.

Further, the apertures 11 are provided in the vicinity of the central portion of the aperture electrode 1 in the Z direction so as to open in the insulating layer 106, and are arranged in a row to form the aperture row 12. In addition, the reference electrode layer 107 is the insulating layer 1
06 is provided on the brush roller 103 side. Furthermore,
The control electrode layer 108 is formed on the upper surface of the insulating layer 106,
Independently provided around the aperture 11. The reference electrode layer 107 is connected to the ground, and a large number of the control electrode layers 1
08 are respectively connected to a large number of signal sources S not shown.

The counter electrode 112 is provided on the opposite side of the brush roller 103 with the aperture electrode 1 in between and with a predetermined space from the aperture electrode 1. The medium P that has entered the space through the insertion opening 117 and has been sent via the guide 115 and the pair of auxiliary rollers 116 passes through this space. The counter electrode 112 has a power source E2.
(Minus (-)). By applying this voltage, the toner T that has passed through the aperture 11 of the aperture electrode 1 is moved and adsorbed on the medium P.

The heat fixing section 102 is composed of a heat roller 113 having a heat source and a press roller 114.
Then, the heat roller 113 and the press roller 11
4 is arranged so that the medium P can pass therethrough.

Next, the operation of the toner jet recording apparatus will be described with reference to FIG. The medium P inserted from the insertion port 117 is conveyed to the recording unit 101. Recording unit 101
In the above, the toner T is
It is pressed against the supply roller 104 and carried. Then, the toner T is supplied to the brush roller 103 by the supply roller 104. At this time, the toner T is supplied to the supply roller 104 and the brush roller 103.
While contacting, rubbing, and being, for example, positively (+) charged. Toner T charged positively (+)
Are carried by the brush roller 103.

The brush roller 103 is scratched by the scraping member 110 in the vicinity of the aperture electrode 1. Then, due to elasticity, when the brush returns to its original position, the toner T carried by the brush in an appropriate amount jumps up. As a result,
The toner T forms a cloud and is supplied to the aperture electrode 1.

Then, the flow of the toner T is modulated by the voltage applied from the signal source S to the control electrode layer 108 of the aperture electrode 1.

At this time, from the drive circuit 3 to the exciter body 2, as shown in FIG.
If a frequency-modulated signal as shown in (1) is applied, as described above, the incident wave on the aperture electrode 1 and the reflected wave do not interfere with each other, and the standing wave is not excited. Therefore, even if the charged toner particles try to adhere to the vicinity of the aperture array 12 due to an image force or the like, a large vibration acceleration is generated at the position of the aperture array 12 due to the incident wave or the reflected wave. Can not. As a result, always stable,
The toner stream is modulated by the signal source and recorded on the medium P.

The positive (+) charged toner T modulated by the negative (-) power source E2 connected to the counter electrode flies toward the counter electrode. And this toner T
Is sucked by the medium P guided by the guide 115 and the pair of auxiliary rollers 116.

Thereafter, the medium P is conveyed to the heat fixing section 102. Then, at this place, the image on the medium P is
The heat roller 113 and the press roller 114 are pressed against each other to be fixed. Since this fixing method is a general method, detailed description thereof will be omitted. Finally, the image-formed medium P is conveyed to the take-out port 118 via the guide 115, and
Taken out.

Next, the function of preventing clogging of the aperture electrode 1 configured as described above will be described with reference to FIGS. When the sine wave signal shown in FIG. 3 is applied from the modulation control signal oscillator 32 to the voltage controlled oscillator 31, as described above, the voltage controlled oscillator 31 outputs the AC electric signal whose frequency is modulated as shown in FIG. To be done. The amplitude of the frequency-modulated electric signal is amplified by the amplifier 33 and applied to the exciter 2. Then, a vibration whose vibration frequency is modulated as shown in FIG. 4 is excited from the exciter 2 onto the aperture electrode 1. Therefore, since the incident wave incident from the exciter 2 and the reflected wave reflected by the reflector 20 do not interfere with each other, it is possible to prevent a standing wave from being generated on the aperture electrode 1 due to the superposition of the two. ..

Aperture electrode 1 constructed as described above
In this case, since a sufficient vibration amplitude can be obtained in the vicinity of the aperture array 12, it is possible to obtain a sufficient vibration amplitude with the aperture 11 provided at any position on the aperture electrode 1, and as a result, all the apertures can be obtained. At position 11, the maximum vibration acceleration can be obtained. For this reason, toner does not adhere to the vicinity of the aperture 11 of the aperture electrode 1, and as a result, it is possible to prevent clogging of the aperture 11. The effect of preventing clogging increases as the acceleration of vibration increases. Therefore, in order to effectively prevent the clogging, the amplitude and frequency of the vibration excited on the aperture electrode may be increased. Generally, when trying to excite a high frequency, its amplitude becomes small.
Therefore, it is necessary to appropriately determine the excitation frequency according to the material of the aperture electrode.

In this embodiment, the voltage controlled oscillator is exemplified as the vibration frequency modulating means of the exciter body.
The method is not limited to this method, and any other method can be used as long as it can modulate the vibration frequency of the exciter, and the effect of the present method is not impaired.

Although the resonator made of a laminated piezoelectric material has been taken as an example of the exciter, any other method such as a method utilizing magnetic force can be used as long as it can excite vibrations in the aperture electrode. Even with the method, the same effect as that of the present invention can be obtained.

Other various modifications are possible without departing from the spirit of the present invention.

[0035]

As is apparent from the above description, according to the image forming apparatus of the present invention, since the standing wave is not excited on the aperture electrode, it is sufficiently close to all the aperture positions on this aperture electrode. It is easy to obtain a large vibration amplitude, and it is possible to easily and effectively prevent the charged toner from depositing on the aperture electrode.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an aperture electrode.

FIG. 2 is an explanatory diagram showing an electrical connection method of a means for generating an excitation signal of an aperture electrode.

FIG. 3 is an explanatory diagram of a control signal input from a modulation control signal oscillator to a voltage control oscillator.

FIG. 4 is an explanatory diagram of a frequency-modulated electric signal applied from a drive circuit to an exciter body.

FIG. 5 is a configuration explanatory view of an image forming apparatus using the aperture electrode shown in FIGS. 1 and 2.

[Explanation of symbols]

 1 Aperture electrode 2 Exciter

Claims (1)

[Claims] 1. An image forming apparatus comprising: an aperture electrode for modulating and controlling charged toner; and an exciter body for exciting the aperture electrode with vibration, wherein the vibration body excites vibration on the aperture electrode. An image forming apparatus, characterized in that the vibration frequency is modulated vibration.