JPH0584962A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To facilitate the matching of the mechanical impedances of an aperture electrode and polymeric piezoelectric elements by directly bonding the polymeric piezoelectric elements near to the aperture electrodes in mechanical properties to the aperture electrode to form an exciting means exciting traveling waves goint along an aperture row direction in order to prevent the adhesion of toner to the aperture electrode. CONSTITUTION:An exciting device constituted of polymeric piezoelectric elements 21, 22 composed of polyvinylidene chloride is bonded to an aperture electrode 1 constituted of a polymeric membrane composed of polyimide or the like. As a result, the mechanical impedance of the exciting device can be easily matched with that of the aperture electrode 1 and the vibration excited by the aperture electrode 1 can be directly controlled and the clogging of the aperture electrode due to vibration can be efficiently prevented.

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,
More specifically, the present invention relates to an image forming apparatus that directly controls modulation of toner by an aperture electrode to form an image on a recording medium.

[0002]

2. Description of the Related Art An image recording apparatus of this type is reported in, for example, US Pat. No. 3,689,935. It is composed of a toner crowder, an aperture electrode and 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 unit that modulates and controls the flow of toner from the toner cloud, and includes an insulating layer having a large number of apertures or openings, and a first electrode layer provided on one surface of the insulating layer. And a plurality of second electrodes provided on the other surface of the insulating layer and independently provided for each of the plurality of apertures. 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 record on a recording medium such as paper.

However, when recording is performed by this image forming apparatus, there is a problem that the aperture portion of the aperture electrode is clogged with toner. That is, for example, when it is desired to obtain a recording density of 240 DPI, since the dot size is 100 μm at the maximum, it is necessary to reduce the inner diameter of the aperture of the aperture electrode to about 50 μm at the maximum, and the toner particles are made to have an image force due to an image force or the like. There is a problem that the aperture electrode is clogged with the toner particles as a result of being deposited on the electrode, and it is difficult to always obtain a stable image output continuously.

The Applicant has therefore proposed to excite a traveling wave on the aperture electrode to prevent the accumulation of toner particles. This method applies a repulsive force larger than the image force or the like that causes the accumulation to the toner particles to be deposited on the aperture electrode due to the vibration acceleration generated by the traveling wave excited on the aperture electrode, thereby This is a method to prevent the accumulation of particles.

However, conventionally, in the image forming apparatus having the above-mentioned structure, the exciting device is generally composed of the vibrating body made of piezoelectric ceramic and the resonator made of metal, and the aperture electrode is soft and Since it was made of a polymer material whose thickness was very thin, it was difficult to directly excite a traveling wave to this aperture electrode. Therefore, a method has been adopted in which the aperture electrode is attached to a resonator made of metal or the like, and a traveling wave is excited in the resonator to indirectly give a vibration acceleration to the aperture electrode.

[0006]

However, since the polymer constituting the aperture electrode and the metal constituting the exciter have very different mechanical properties, the mechanical impedances of the two are matched and the excitation is performed. It was very difficult to efficiently apply vibration acceleration to the aperture electrode due to the vibration excited by the device. Also, since the vibration excited on the aperture electrode cannot be controlled directly,
Various vibrations are excited on the aperture electrode, and as a result, problems such as noise are generated due to the beats of these various film vibrations.

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 in which the aperture electrode can be excited efficiently and directly.

[0008]

To achieve this object, an image forming apparatus of the present invention is provided with an image including an aperture electrode that modulates and controls charged toner, and an exciter that excites vibration on the aperture electrode. In the forming apparatus, the aperture electrode is made of a polymer material, and the excitation body is made of a polymer piezoelectric material having substantially the same mechanical properties as the aperture electrode.

[0009]

In the image forming apparatus of the present invention having the above-mentioned structure, since the exciter for exciting the aperture electrode is made of the polymeric piezoelectric material, it is easy to match the aperture electrode with its mechanical impedance. , Because the vibration excited to the aperture electrode can be controlled directly,
It is possible to efficiently prevent clogging of the aperture electrode due to vibration.

[0010]

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

In FIG. 3, the image forming apparatus 100 comprises a recording section 101 and a heat fixing section 102. An insertion opening 117 and an ejection opening 118 are provided on the side of the image forming apparatus 100. In the recording unit 101, a medium P such as plain paper that has entered through the insertion slot 117.
Then, an image or the like is formed. 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 FIGS. In FIG. 1, the aperture electrode 1 includes a large number of apertures 11, an insulating layer 106,
The reference electrode layer 107, a large number of control electrode layers 108, and an excitation device 2 that excites a traveling wave on the aperture electrode 1. The aperture electrode 1 generally includes an insulating layer 106 made of a polymer material such as polyimide having a thickness of about several tens [μm] and a reference electrode layer 107 and a control electrode layer 108 made of a metal such as copper. 1-2 [μm]
It is formed by a method such as vapor deposition with a certain thickness. In the aperture electrode 1 configured in this way, the reference electrode layer 107 and the control electrode layer 108 are much thinner than the insulating layer 106. Very close to the mechanical properties of layer 106.

The excitation device 2 includes an exciter body 21 joined to one end of the aperture electrode 1 in the X direction in order to excite the aperture electrode 1, and an X of the aperture electrode 1.
The reflected wave absorber 22 is joined to the other end of the direction. The excitation body 21 and the reflected wave absorber 22 are made of, for example, a polymeric piezoelectric material such as polyvinylidene fluoride (hereinafter abbreviated as PVDF). Here, this PVDF is a polarized polymer that is polarized under a strong electric field and imparts stable polarization to the film, and since the chain in the molecular form contains atoms having a dipole moment, it is in the electric field. It is a polymer material that exhibits large piezoelectricity and pyroelectricity, and in addition to the advantages unique to polymer materials such as impact resistance, flexibility, and low acoustic impedance, there is a change in performance due to drive voltage and changes over time. Inorganic piezoelectric materials, that is, piezoelectric ceramics, have various characteristics such as few.

Next, the exciter body 21 is electrically connected to a drive circuit 31 which outputs an electric signal of a predetermined frequency,
Further, the reflected wave absorber 22 has an impedance body 32.
Is electrically connected to the impedance body 32, and the impedance body 32 suppresses the generation of the reflected wave by consuming the vibration energy absorbed by the reflected wave absorber 22. That is, by adjusting the impedance body, the impedance with respect to the vibration of the aperture electrode 11 on the reflected wave absorber side is changed. Therefore, impedance matching is performed by appropriately adjusting the impedance (resistance value, reactance value) of the impedance body,
The aperture electrode 1 viewed from the side of the exciter 21 is equivalent to one that continues infinitely in terms of vibration. Therefore, the reflected wave is not generated, but only the traveling wave. Therefore, the generation of standing waves can be suppressed.

Further, the apertures 11 are provided in the vicinity of the Z direction central portion of the aperture electrode 1 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 (not shown).

The counter electrode 112 is provided on the opposite side of the brush roller 103 with the aperture electrode 1 interposed therebetween 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 image forming apparatus will be described with reference to FIG. Medium P inserted from the insertion slot 117
Are conveyed to the recording unit 101. In the recording unit 101, the toner T is pressed against the supply roller 104 by the supply blade 111 and carried. Then, the toner T is supplied by the supply roller 104.
Are supplied to the brush roller 103. At this time, the toner T rubs while contacting the supply roller 104 and the brush roller 103, and is, for example, positively (+) charged. The positively charged toner T is 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.

The flow of the toner T is modulated by the voltage applied from the signal source to the control electrode layer 108 of the aperture electrode 1 corresponding to the image to be formed.

At that time, from the drive circuit 31 to the exciter 21,
When an electric signal of a predetermined frequency is applied, a traveling wave propagating in the X direction is excited in the aperture electrode 1 as described above. Therefore, even if the charged toner particles try to adhere to the vicinity of the aperture array 12 due to the image force or the like,
Since a large vibration acceleration is generated at the position of the aperture array 12 due to the vibration, it cannot be attached. As a result, the toner flow is always stably modulated by the signal source and recorded on the medium P.

The toner T, which is positively (+) charged and 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. The drive circuit 3 is attached to the exciter 21 during image formation.
When an electric signal having a predetermined frequency is applied from No. 1, bending vibration having a displacement in the Z direction is excited on the aperture electrode 1. This vibration propagates in the X direction, and when the propagated vibration reaches the other end of the aperture electrode 1, the reflected wave absorber 2
The vibration energy is absorbed by 2, and the absorbed energy is consumed by the impedance body 32. Therefore, no reflected wave is generated, and a traveling wave traveling along the X direction, that is, along the direction of the aperture array 12 is generated on the aperture electrode 1.

At this time, as described in detail above, the aperture electrode and the exciter that excites the vibration to the aperture electrode are made of a polymer material having mechanical properties close to or substantially equal to each other, and both are directly bonded. Therefore, impedance matching between the two is facilitated, and as a result, the vibration energy of the exciter is efficiently supplied to the aperture electrode, and the traveling wave can be excited on the aperture electrode with high efficiency. Further, since the vibration excited on the aperture electrode can be directly controlled, it becomes possible to excite only the desired vibration on the aperture electrode.

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 clogging, the amplitude and frequency of vibration may be increased. Generally when trying to excite high frequencies,
Its amplitude becomes smaller. Therefore, it is necessary to appropriately determine the excitation frequency according to the material of the aperture electrode.

In this embodiment, the vibration excited on the aperture electrode in order to prevent clogging is changed to Z
Although a traveling wave having a vibration displacement in the X direction and propagating in the X direction has been described as an example, the present invention is not limited to this vibration and any vibration having a maximum point of the vibration amplitude in the vicinity of the aperture array of the aperture electrode may be used. The same effect can be obtained not only with traveling waves but also with standing waves.

Further, as the method for exciting the traveling wave, the method using the vibrating body and the reflected wave absorbing body has been described as an example.
The method is not limited to this method, and any other method that can excite a traveling wave does not impair the effects of the present invention.

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

[0033]

As is apparent from the above description, in the image forming apparatus of the present invention, the aperture electrode and the exciter for exciting the aperture electrode are made of a polymer material. The electrodes can be excited efficiently and directly by the exciter. As a result, it is possible to easily prevent toner from adhering to the aperture electrode without causing a problem such as noise.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing an electrical connection method of the excitation device of the aperture electrode.

FIG. 3 is an explanatory diagram showing a schematic configuration of an image forming apparatus using the aperture electrode and the excitation device shown in FIGS. 1 and 2.

[Explanation of symbols]

 1 Aperture Electrode 2 Excitation Device 21, 22 Polymer Piezoelectric Body 100 Image Forming Device

Claims (1)

[Claims] 1. An image forming apparatus comprising: an aperture electrode for controlling the modulation of charged toner; and an exciter for exciting the aperture electrode to vibrate, wherein the aperture electrode is made of a polymer material, and the exciter is An image forming apparatus comprising a piezoelectric polymer having substantially the same mechanical properties as the aperture electrode.