JPH0655761A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Object] To provide an image forming apparatus capable of obtaining a uniform and stable image by using a diaphragm capable of effectively preventing clogging without affecting the control of toner flow. . [Structure] The electrode excitation device 2 includes a plurality of diaphragms 201, 20.
Each of the diaphragms 201, 2 composed of 2, 203 and divided
The widths of 02 and 203 are set to 1/2 or less of the wavelength of the traveling wave propagating through the diaphragm so that no vibration node is formed in the width direction, and the diaphragms 201, 202 and 203 are
The distance is set so that the distance is equal to or less than half the wavelength of the traveling wave propagating through the aperture electrode 10.

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 specifically to an image forming apparatus for directly controlling the flow of charged toner by an aperture electrode to form an image on a recording medium. It is about.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus of this type is disclosed in, for example, the specification of 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 generates a cloud of charged toner,
It is a means for 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, and is provided on one surface of the insulating layer having a large number of apertures or openings. A first electrode layer,
The second electrode layer is provided on the other surface of the insulating layer and is independently provided for each of the plurality of openings. Further, the counter electrode attracts and holds a recording medium such as paper, and is arranged so as to face the aperture electrode.

The image forming apparatus configured as described above is
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.

When an image is formed by this image forming apparatus, for example, when trying to obtain a recording density of 240 DPI, the maximum dot size is 100 μm, so the inner diameter of the aperture of the aperture electrode is as small as about 50 μm. If the inner diameter of the aperture is reduced in this way, toner particles will be deposited on the aperture electrode due to image force, etc. As a result, the toner particles will clog the aperture of the aperture electrode with the toner and will always be stable. There is a problem that it is difficult to obtain the image output.

[0006] Therefore, the present applicant has filed Japanese Patent Application No. 4-14061.
As stated in the specification and drawings attached to the
A method has been proposed in which a diaphragm provided with an exposure hole through which toner particles can pass is attached to the aperture electrode, and a traveling wave is excited in the diaphragm to prevent the toner particles from accumulating on the aperture electrode. In this method, the toner particles to be deposited on the aperture electrode are subjected to the above-mentioned image force, etc. This is a method in which a larger repulsive force is applied to prevent the accumulation of toner particles.

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. It is necessary to provide the other end 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. there were.

When a traveling wave is excited on the diaphragm as described above, it is generally known that, in such a diaphragm, if the frequency of the traveling wave is fixed, the square root of the width and the square root of the thickness are substantially inversely proportional to each other. ing. Further, the minimum limit of the width of the diaphragm needs to be about the same as the width of the opening region provided on the aperture electrode.

[0009]

However, as a method of driving the aperture electrodes in the conventional image forming apparatus as described above, for example, an aperture electrode adopting a matrix driving method as disclosed in Japanese Patent Publication No. 59-43317. In the above, since the openings are provided in a grid pattern, the width of the region where the openings are provided becomes large.

Therefore, the minimum permissible dimension in the width direction of the diaphragm becomes large, and the width cannot be made too small. 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. For example, when the width of the diaphragm is 5mm, the traveling wave frequency is 25k.
If the frequency is Hz, the thickness of the diaphragm will be about 0.3 mm.
On the other hand, since the aperture electrode is generally 25 to 50 μm thick, the diaphragm is about 10 times thicker than the aperture electrode. Therefore, when adopting a configuration in which the aperture electrode is excited by such a diaphragm, there is a problem that the control of the toner flow by the aperture electrode is adversely affected. Furthermore, if the diaphragm is made as thick as or less than the aperture electrode, a vibration node can be created in the width direction of the diaphragm, so clogging occurs at the opening near this node, and the vibration is uniform and stable. There was a problem that the obtained image could not be obtained.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to use a vibrating plate which can effectively prevent clogging without affecting control of the toner flow. An object of the present invention is to provide an image forming apparatus capable of obtaining a uniform and stable image.

[0012]

In order to achieve this object, an image forming apparatus of the present invention comprises an aperture electrode for modulating and controlling the flow of charged toner, and an excitation device attached to the aperture electrode. Further, the excitation device has a plurality of diaphragms, the plurality of diaphragms,
Each of the widths is ½ or less of the wavelength of the traveling wave propagating on the diaphragm, and is arranged at intervals of ½ or less of the wavelength of the traveling wave propagating on the aperture electrode.

[0013]

The exciter in the image forming apparatus of the present invention having the above-described structure has a plurality of diaphragms, and each of the plurality of diaphragms has a width of 1 of the wavelength of the traveling wave propagating on the diaphragm. / 2 or less, and they are arranged at intervals of 1/2 or less of the wavelength of the traveling wave propagating on the aperture electrode.

[0014]

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

In FIG. 4, 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. 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 heat fixed. After that, the medium P is sent to the ejection port 118 via the guide 115.

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 rotating direction of the brush roller 103 are provided in contact with the brush roller 103. 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. The supply roller 104 and the supply blade 111 are covered with a case K. The aperture electrode portion 1 is provided above the brush roller 103.

Next, with reference to FIGS. 1 to 3, 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. An electrode excitation device 2 is attached to the aperture electrode 10. The electrode excitation device 2 includes a plurality of diaphragms 201, 202, 203 made of an elastic material such as metal, and the diaphragms 201, 202, 203. An exciter body 21 attached to one end of the vibrating plate 201, 202, 202,
It is composed of a reflected wave absorber 22 attached to the other end of 203.

The vibrating plates 201, 202 and 203 have
A large number of exposure holes 30 are provided, and the aperture electrode 1
It is attached by means such as adhesion so as to come to a position corresponding to the opening portion 0 of 0, and toner is supplied to the opening portion 11 through these exposure holes 30.

The diaphragms 201, 20 having the above-mentioned structure
2 and 203, the vibration plates 201 and 202,
The width of 203 is determined according to the following equation so that a vibration node cannot be formed in the width direction for each of them.

W <λ 1/2 In this equation, w is the width of the diaphragms 201, 202 and 203, and λ1 is the wavelength of the traveling wave propagating on the diaphragms 201, 202 and 203. For example, as a diaphragm,
When a stainless steel plate having a thickness of 0.05 mm is used and the frequency of the traveling wave is 25 kHz, the width w may be about 2 mm or less. Therefore, it is possible to use a diaphragm having a thickness substantially the same as the thickness of the aperture electrode 10.

Further, the diaphragms 201, 202 and 203 whose dimensions are determined as described above are attached to the aperture electrode 10 so that the distance b satisfies the condition of b <λ2 / 2. If the aperture electrode 10 is attached so as to satisfy this condition, the aperture electrode 10 completely follows the vibration of the diaphragms 201, 202, and 203. Here, λ2 is the aperture electrode 10
It is the wavelength of the traveling wave propagating above. For example, when a polyimide film having a thickness of 0.025 mm is used as the aperture electrode, the distance b may be about 0.8 mm or less.

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
The generation of reflected waves at the reflection ends of 1, 202, 203 is suppressed, and only the traveling wave propagating in one direction on the diaphragms 201, 202, 203 is excited. The diaphragms 201, 202, 203 of the electrode excitation device 2 configured as described above
Vibration that follows the traveling wave excited by the aperture electrode 1
Excited above zero.

Next, as shown in FIG.
As shown in FIG. 3 and FIG. 3, the column electrodes 107 provided on the upper surface of the insulating layer 106 and the row electrodes 108 provided on the lower surface of the insulating layer 106 are formed in an oblique lattice shape, and the column electrodes 107 and the row electrodes 108 are formed. The opening 11 is formed on the intersection.
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. However, its specific structure and action are general ones, and the effect of the present invention. Since it has nothing to do with that, its explanation is omitted here.

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. Then, the medium P that has entered from the insertion opening 117 and is sent via the guide 115 and the pair of auxiliary rollers 116 passes through this space. This counter electrode 112
Is connected to a power source E2 (minus (-)). By applying this voltage, the toner T that has passed through the opening 11 of the aperture electrode 10 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 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.
It is pressed against and is carried. Then, the toner T is supplied to the brush roller 10 by the supply roller 104.
3 is supplied. At this time, the toner T is supplied to the supply roller 10
While being in contact with the brush roller 4 and the brush roller 103, they are rubbed and charged to, for example, plus (+). The positively charged toner T is carried on the brush roller 103.

The brush roller 103 is scratched by the scraping member 110 in the vicinity of the aperture electrode 10. When the brush returns to its original position due to elasticity, 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 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 that time, from the drive circuit 31 to the exciter 21,
When an electric signal of frequency fr is applied, the excitation body 21 expands and contracts, and due to this expansion and contraction, the vibration plates 201, 202, 2
03 includes the diaphragms 201, 202, 20 as described above.
A traveling wave propagating in the length direction of 3 is excited. At this time,
The charged toner particles are transferred to the aperture array 12 by a mirror image force or the like.
Even if it tries to adhere to the vicinity, at the position of the opening row 12,
Since a large vibration acceleration is generated by the traveling wave, it cannot be attached. In addition, the aperture electrode 10 is the diaphragm 2
Since the vibrations of 01, 202, and 203 are completely followed, the aperture electrode 10 does not cause film vibration and generate noise. As a result, the toner flow is modulated by the column electrode driving element or the row electrode driving element (not shown),
It is recorded on the medium P.

The toner T modulated and positively (+) charged by the negative (-) power source E2 connected to the counter electrode.
Flies toward the counter electrode. Then, the toner T is attracted to 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 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. Then, finally, the image-formed medium P is conveyed to the take-out 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. 1 to 3. When an electric signal of a predetermined frequency fr is applied from the drive circuit 31 to the excitation body 21 during image formation, the excitation body 21
It expands and contracts at the frequency fr. This vibration causes the diaphragm 201,
202 and 203 are excited, and this vibration is applied to each diaphragm 2.
When the other ends of 01, 202, and 203 are reached, as described above, the reflected wave absorber 22 absorbs the vibration energy, and the absorbed energy absorbs the vibration energy.
Consumed in. Therefore, the vibration plates 201, 202,
At the reflection end of 203, no reflected wave is generated. as a result,
Only the traveling wave propagating in the length direction is excited on each of the diaphragms 201, 202 and 203. Moreover, since the width w of each of the vibration plates 201, 202, and 203 is set so as to satisfy the condition of w <λ1 / 2, use a thin vibration plate that does not adversely affect the control of the toner flow. However, no node occurs in the width direction, that is, in the direction orthogonal to the traveling direction of the traveling wave. As a result, each diaphragm 20
Even if the opening 11 is provided at any position of 1, 202 and 203, sufficient vibration acceleration can be applied, so that toner does not adhere to the vicinity of the opening 11 of the aperture electrode 1. Furthermore, each diaphragm 201,
Interval b for attaching 202 and 203 to the aperture electrode 10
Is determined under the condition expressed by b <λ2 / 2.
Aperture electrodes 10 attached to 01, 202 and 203
Is a diaphragm 201, 202, 2 without causing membrane vibration.
Since it vibrates following the vibration of No. 03, it is possible to prevent the generation of noise due to the film vibration. As a result, there is no noise and there is no influence on the control of the toner flow, and the opening 1
No. 1 clogging can be prevented.

In this embodiment, the number of vibrating plates is three, but the number of vibrating plates may be three or more or less than that of the present invention. Similar effects can be achieved.

Further, 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 electric energy into mechanical energy can be used. Alternatively, an electrostrictive element, a magnetostrictive element, or the like may be directly used, or a resonator may 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. However, 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.

[0038]

As is apparent from the above description, the excitation device in the image forming apparatus of the present invention has a plurality of diaphragms, and the plurality of diaphragms have respective widths propagating on the diaphragm. The wavelength of the traveling wave is equal to or less than 1/2 and the distance of the traveling wave propagating on the aperture electrode is equal to or less than 1/2. Therefore, the control of the toner flow is not affected. A diaphragm that is thin and can effectively prevent toner from adhering to the aperture electrode can be used for the aperture electrode excitation device, and a uniform and stable image can be easily obtained.

[Brief description of drawings]

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

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

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

FIG. 4 is a configuration diagram showing an embodiment of an image forming apparatus of the present invention.

[Explanation of symbols]

 2 Excitation device 10 Aperture electrode 201 Vibrating plate 202 Vibrating plate 203 Vibrating plate

Claims (1)

[Claims] 1. An image forming apparatus comprising: an aperture electrode for modulating and controlling the flow of charged toner; and an excitation device attached to the aperture electrode, wherein the excitation device has a plurality of diaphragms. The plurality of diaphragms are arranged at intervals such that the width of each of the plurality of diaphragms is ½ or less of the wavelength of the traveling wave propagating on the diaphragm, and ½ or less of the wavelength of the traveling wave propagating on the aperture electrode. An image forming apparatus characterized by the above.