JPH0655763A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Purpose] An electric field is formed in the opening of the diaphragm of the electrode excitation device, and a flying force is applied to the toner in the opening of the diaphragm by this electric field, so that the toner in the opening is removed. To prevent stagnation and obtain a clear image. [Structure] The aperture electrode unit 1 includes an aperture electrode 10
And the aperture electrode excitation device 2. The aperture electrode excitation device 2 includes metal plates 201, 202, 203.
A diaphragm 20 in which insulating plates 204, 205 and 206 are alternately laminated, an exciter 21 attached to one end to excite the diaphragm 20, and an exciter 21 attached to the other end of the diaphragm 20. The reflected wave absorber 22 is formed. The metal plate 201,
Reference numerals 202 and 203 are connected to power sources 331, 332, and 333, respectively, and an arrow A is drawn in the opening 30 of the diaphragm 20.
An electric field is formed as indicated by.

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 Conventionally, an image forming apparatus of this type is disclosed in, for example, US Pat. No. 3,689,935.
This image forming apparatus 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.

This aperture electrode is a control means for modulating and controlling the flow of toner from the toner cloud.
It is composed of an insulating layer having a large number of apertures, a first electrode layer provided on one surface of the insulating layer, and a second electrode layer provided on the other surface of the insulating layer. 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 constructed as described above, the flow of the toner supplied by the toner crowder is controlled by an electric signal applied to the aperture electrode and the counter electrode, so that it is recorded on a recording medium such as paper. An image 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, the toner particles are deposited on the aperture electrode due to the image force, etc. As a result, the aperture is clogged with the toner particles, and it is difficult to always obtain a stable image output. There was a problem.

[0006] Therefore, the present applicant has filed Japanese Patent Application No. 4-14061.
As described in the description and drawings attached to the application of No. No. of the publication, a diaphragm provided with an opening through which toner particles can pass is attached to the aperture electrode, and a traveling wave is excited in this diaphragm to form an aperture. We proposed a method to prevent toner particles from accumulating on the electrodes. In this method, the toner particles to be deposited on the aperture electrode are subjected to the above-mentioned image force, etc., which causes the toner particles to be deposited on the aperture electrode by imparting to the toner particles a vibration acceleration generated on the aperture electrode by the traveling wave excited by the diaphragm. This is a method for preventing the accumulation of toner particles by applying a larger repulsive force.

In the image forming apparatus as described above, since the shape of the diaphragm is generally a rectangular flat plate, in order to excite the traveling wave on the diaphragm, an exciter is provided at one end of the diaphragm. The other end is provided with a reflected wave absorber that absorbs and consumes the energy of the vibration of the traveling wave propagating on the diaphragm to prevent the generation of the reflected wave, and excites only the traveling wave on the diaphragm.

[0008]

However, in the case where a traveling wave is excited in the diaphragm as described above, if the frequency of the traveling wave is fixed in such a diaphragm, generally,
It is known that the square root of the width and the thickness is almost inversely proportional. Further, the minimum limit of the width of the diaphragm needs to be approximately the same as the width of the aperture region provided on the aperture electrode.

However, as an aperture electrode driving method, for example, in the aperture electrode adopting the matrix driving method as shown in Japanese Patent Publication No. 59-43317, the aperture is provided on the grid point, and therefore the aperture is provided. The width of the area to be covered becomes large. Therefore, since it is necessary to increase the width of the region where the opening of the diaphragm is provided, the minimum allowable dimension in the width direction of the diaphragm becomes large, and the width cannot be reduced so much. As a result, if the diaphragm is composed of one plate, the thickness of the diaphragm, which is determined by the width of the diaphragm and the frequency of the traveling wave, increases. Further, in general, since the diaphragm is made of metal, when the diaphragm becomes thick, an electric field is not formed inside the opening of the diaphragm, and as a result, the flying force is not given to the toner inside the opening, There is a problem that the toner cannot fly to the recording medium and a clear image cannot be obtained.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to give a flying force to the toner in the opening of the diaphragm so that the toner stays in the opening. It is an object of the present invention to provide an image forming apparatus that prevents the occurrence of the above-mentioned problem and can easily obtain a clear image.

[0011]

To achieve this object, an image forming apparatus of the present invention comprises an aperture electrode for modulating and controlling charged toner, and an exciting device for vibrating the aperture electrode. In addition, the exciter further includes a diaphragm including a plurality of stacked plate members.

[0012]

In the image forming apparatus of the present invention having the above-mentioned structure, the openings provided in the vibrating plate are formed by applying a predetermined voltage to each layer of the vibrating plate composed of a plurality of laminated plate members. An electric field is formed in the part, and the electric field gives a flying force to the toner.

[0013]

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
Reference numeral 00 includes a recording unit 101 and a heat fixing unit 102. An insertion opening 117 and an ejection opening 118 are provided on the side of the toner jet recording apparatus 100. Then, in the recording unit 101, the insertion opening 117
An image or the like is recorded on a medium P such as plain paper that has been inserted. After that, the image and the like on the medium are thermally fixed in the heat fixing unit 102. Further, the medium P is a guide 115.
And is sent to the outlet 118.

The recording section 101 comprises a rotatable brush roller 103, an aperture electrode section 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 rotation 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
Are 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
Are covered by a case K.

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

Next, referring to FIGS. 1 to 4, the structure of the aperture electrode and the excitation device for the aperture electrode will be described. In FIG. 1, the aperture electrode section 1 is composed of an aperture electrode 10 and an aperture electrode excitation device 2. 2 and FIG.
As shown in FIG. 5, the column electrode 107 provided on the upper surface of the insulating layer 106 and the row electrode 10 provided on the lower surface of the insulating layer 106.
8 are formed in a diagonal grid pattern, and the column electrodes 107 and the row electrodes 10 are provided.
An aperture 11 is formed on the intersection of eight. Also,
The column electrode 107 is connected to a column electrode driving element (not shown), and the row electrode 108 is also connected to a row electrode driving element (not shown). Such a matrix driving type aperture electrode has a structure as shown in the above-mentioned Japanese Patent Publication No. 59-43317, for example, but its specific structure and operation are general, and the effects of the present invention are as follows. Has nothing to do with it, so its details are omitted here.

Next, as shown in FIG. 1 or 4, the electrode excitation device 2 attached to the aperture electrode 10 includes metal plates 201, 202 and 203 and insulating plates 204 and 205, respectively.
A diaphragm 20 in which 206 are alternately stacked, and this diaphragm 2
It is composed of an exciter body 21 attached to one end for exciting 0, and a reflected wave absorber 22 attached to the other end of the diaphragm 20. The metal plates 201, 202, 203
Is a power source 33 that outputs predetermined voltages V1, V2, and V3, respectively.
1, 332, 333 are connected. Here, these voltages V1, V2, and V3 are set so as to satisfy the relationship represented by V11>V10>V1>V2>V3> V12. In the above equation, V10 is the voltage applied to the row electrode 108 during recording, V11 is the voltage applied to the column electrode 107 during recording,
V12 represents the voltage applied to the counter electrode 112.

The vibrating plate 20 has a large number of openings 3.
0 is provided on the aperture electrode 10 by means such as adhesion so that the large number of openings 30 are located at positions corresponding to the apertures 11, and the toner passes through these openings 30 and the aperture 30 is formed. 11 is configured to be supplied. The opening 30 has a substantially circular shape, and its diameter is such that the aperture electrode 10 oscillates completely following the vibration of the diaphragm 20.
It is set so as to be smaller than 1/2 of the wavelength of the elastic wave propagating over 0.

The excitation body 21 is composed of a laminated piezoelectric body, and is electrically connected to a drive circuit 31 which outputs an electric signal having a frequency fr [kHz]. The reflected wave absorber 22 is made of a laminated piezoelectric material like the excitation body 21 and is electrically connected to the impedance body 32. The impedance body 32 absorbs the vibration energy absorbed by the reflected wave absorber 22. The diaphragm 20 by consuming
It suppresses the generation of reflected waves at the reflection end of, and excites only the traveling waves propagating in one direction on the diaphragm 20. Vibration following the traveling wave excited on the diaphragm 20 of the electrode excitation device 2 configured as described above is excited on the aperture electrode 10.

The aperture electrode 1 is provided on the opposite side of the brush roller 103 with the aperture electrode 1 interposed therebetween.
The counter electrode 112 is provided with 0 and a predetermined space. Enter this space from the insertion slot 117,
The medium P sent through the guide 115 and the pair of auxiliary rollers 116 passes through. The counter electrode 112 is connected to the power source E2 (minus (-)). By applying this voltage, the aperture 11 of the aperture electrode 10 is
The toner T that has passed through is 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 1
The medium 14 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. The medium P inserted from the insertion port 117 is
It is conveyed to the recording unit 101. In the recording unit 101, the toner T is supplied by the supply blade 111 to the supply roller 104.
Is pressed against and is supported. Then, the toner T is supplied to the brush roller 103 by the supply roller 104. At this time, the toner T is in contact with the supply roller 104 and the brush roller 103,
It rubs and becomes positively charged, for example.
The toner T charged positively (+) is transferred to the brush roller 10
3 is supported.

The brush roller 103 is scratched by the scraping member 110 in the vicinity of the aperture electrode 10. 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 becomes a cloud and is supplied to the aperture electrode unit 1.

The flow of the toner T is modulated by the voltage applied to the column electrode 107 or the row electrode 108 of the aperture electrode 10 from the column electrode driving element (not shown) or the row electrode driving element (not shown).

At this time, when an electric signal of frequency fr is applied to the excitation body 21 from the drive circuit 31, the excitation body 21 expands and contracts, and the expansion and contraction causes the vibration plate 20 to move in the longitudinal direction of the vibration plate 20 as described above. The traveling wave propagating to is excited.
At this time, even if the charged toner particles try to adhere to the vicinity of the aperture 11 due to an image force or the like, the aperture 11
Since a large vibration acceleration due to the traveling wave is generated at the position of, it cannot be attached. Also, the aperture electrode 1
Since 0 completely follows the vibration of the diaphragm 20, the aperture electrode 10 does not cause film vibration and generate noise.

Further, as described in detail above, the diaphragm 20
Power sources 331, 33 on the metal plates 201, 202, 203 of
An electric field is formed inside the opening 30 by the voltage applied by the electrodes 2 and 333.
The toner T supplied to the counter electrode 11 is generated by this electric field.
Flyed to 2. As a result, the flow of toner is modulated by the column electrode driving element or the row electrode driving element (not shown) without being affected by the vibration plate 20, and is further modulated by the minus (-) power source E2 connected to the counter electrode. The positively (+) charged toner T thus ejected flies toward the counter electrode. Then, the toner T is transferred to the guide 115.
Then, the medium P is attracted to the pair of auxiliary rollers 116, and an image corresponding to the image signal is recorded on the medium P.

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 brought into pressure contact with each other to be heat-fixed. This fixing method is
Since this is a general method, detailed description is omitted. Finally, the image-formed medium P is conveyed to the ejection port 118 via the guide 115, and
Taken out.

Next, the operation of the aperture electrode section 1 configured as described above will be described with reference to FIGS. When an electric signal having a predetermined frequency fr is applied from the drive circuit 31 to the excitation body 21 during image formation, the excitation body 21 expands and contracts at the frequency fr. This vibration excites the vibration plate 20, and when this vibration reaches the other end of the vibration plate 20, as described above, the reflected wave absorber 22 absorbs the vibration energy, and the absorbed energy absorbs the vibration energy. Consumed in. Therefore, no reflected wave is generated at the reflecting end of the diaphragm 20. As a result, only the traveling wave propagating in the length direction is excited on the diaphragm 20.
In the aperture electrode portion 1 configured in this way,
Since the traveling wave excited by the exciter 2 can obtain sufficient vibration acceleration in the vicinity of the aperture array 12, it is possible to obtain sufficient vibration acceleration with the aperture 11 provided at any position on the aperture electrode 10. As a result, the maximum vibration acceleration can be obtained at all the positions of the apertures 11. For this reason, the toner does not adhere to the vicinity of the aperture 11 of the aperture electrode 10, and as a result, the clogging of the aperture 11 can be prevented.

Further, the metal plate 20 constituting the vibrating plate 20.
1, 202, and 203 have power supplies 331, 332, 333.
Thus, the voltages V1, V2 and V3 are applied. As described above, these voltages V1, V2, and V3 have the relationship of V11>V10>V1>V2>V3> V12, so that the opening 30 of the diaphragm 20
As shown by an arrow A in FIG.
An electric field is formed from the side toward the counter electrode 112. Therefore, the positively charged toner T in the opening 30 receives a force proportional to the electric field strength of the electric field A, the toner T, and the charge amount in the same direction as the electric field A. By this force,
Since the toner T can receive the flying force even when flying through the opening 30, the toner T does not stay in the opening 30 during recording and the aperture of the aperture electrode 10 is prevented by the column electrode 107 and the row electrode 108. Modulation is controlled by the electric field formed at 11, and the recording medium is supplied and recorded toward the medium P. As a result, a clear image is always and stably formed on the medium P.

In this embodiment, the number of metal plates which are laminated to form the diaphragm is three, but
Whether the number of metal plates is 3 or more or less, the same effect as the present invention can be obtained regardless of the number of metal plates.

In the present embodiment, the method of using the laminated piezoelectric element is exemplified as the method of exciting the diaphragm, but the method is not limited to this, and any element capable of converting electrical energy into mechanical energy can be used. Alternatively, an electrostrictive element, a magnetostrictive element, or the like can be used directly, or a resonator can be used.

Further, the method of exciting the traveling wave has been described by taking the method of using the exciter and the reflected wave absorber as an example, but the method is not limited to this method, and any method capable of exciting the traveling wave can be used. However, other methods do not impair the effects of the present invention. 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, the vibrating plate is formed by laminating a plurality of plate-shaped members, and a voltage is applied to each plate-shaped member. By doing so, since an electric field can be formed in the opening of the diaphragm, it is possible to give a flying force to the toner by this electric field, and as a result, the toner does not stay in the opening and a clear image is obtained. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an aperture electrode excitation device used in an image forming apparatus of the present invention.

FIG. 2 is a top view showing a configuration of an aperture electrode used in the image forming apparatus of the present invention.

3 is a bottom view of the aperture electrode shown in FIG. 2. FIG.

4 is a cross-sectional view of an opening of a diaphragm of the aperture electrode excitation device shown in FIG.

FIG. 5 is a diagram showing a schematic configuration of an image forming apparatus of the present invention.

[Explanation of symbols]

 2 electrode excitation device 10 aperture electrode 20 diaphragm

Claims (1)

[Claims] 1. An image forming apparatus comprising: an aperture electrode for modulating and controlling charged toner; and an exciting device for giving vibration to the aperture electrode, wherein the exciting device is a vibration composed of a plurality of laminated plate-like members. An image forming apparatus having a plate.