JPH0655762A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Purpose] Image formation that can always obtain a perfect print result in the entire print width regardless of the non-uniformity of vibration at the end of the area where the aperture electrode opening is provided. Providing equipment. The aperture electrode 1 includes a large number of openings 11, an insulating layer 106, a reference electrode layer 107, and a large number of control electrode layers 10.
A diaphragm 20, an exciting body 21 for exciting the diaphragm 20, and an electrode exciting device 2 including a reflected wave absorber 22 are attached to the aperture electrode 1. The diaphragm 20 is provided with an exposure hole 201, and toner particles can be supplied to the opening 11 of the aperture electrode 1 through the exposure hole 201. The exposure hole 201 is a printing range 2 which is a range in which the opening 11 used for the printing operation is provided on the aperture electrode 1.
It is provided on the diaphragm 20 over a range 203 wider than 02.

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, 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 multiple 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.

[0008]

However, in the vibrating plate having the above-mentioned exposed holes, the mechanical vibration of the vibrating plate is in the boundary region between the region where the exposed portion is formed and the region where the exposed portion is not formed on the vibrating plate. Characteristics change greatly. In such regions where the mechanical properties are greatly different, the propagating vibration energy is reflected and standing waves are generated, which causes the vibration of the diaphragm to become non-uniform and unstable. As a result, in this boundary region, that is, in the vicinity of the end of the exposed hole, the vibration acceleration applied to the aperture electrode greatly changes depending on the place and time, and the image formed by the opening provided near this end is , Uneven due to, for example, hole clogging,
There was also the problem of becoming unstable.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to form an image in which a uniform and stable image can be formed over the entire width of the aperture electrode, that is, over the entire width of the printing range. To provide a device.

[0010]

In order to achieve this object, an image forming apparatus of the present invention has an aperture and an aperture electrode for modulating and controlling the flow of toner passing through the aperture, and the aperture electrode. And a diaphragm having an exposure hole capable of exposing the opening, and a region where the exposure hole is formed on the diaphragm is larger than a region where the opening is formed on the aperture electrode. It is getting wider.

[0011]

In the image forming apparatus of the present invention having the above-mentioned structure, since the exposure hole of the diaphragm is formed in a wider area than the area where the opening is formed on the aperture electrode, the exposure hole is formed on the diaphragm. The non-uniformity or instability of the vibration of the diaphragm in the boundary region between the region where the mark is formed and the region where the mark is not formed has no influence on the image formed on the recording medium.

[0012]

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 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 put in, and the image on the medium is thermally fixed in the heat fixing unit 102. After that, the medium P is sent to the take-out 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 forced by the supply blade 111 by the supply roller 104.
To be supplied to. The supply roller 104 and the supply blade 111 are covered with a case K. The aperture electrode unit 1 is the brush roller 103.
Is provided above.

Next, referring to FIGS. 1 and 2, 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. This aperture electrode 10 has a large number of openings 1
1, an insulating layer 106, a reference electrode layer 107, and a large number of control electrode layers 108. This aperture electrode 1
An electrode excitation device 2 is attached to the electrode 0, and the electrode excitation device 2 includes a diaphragm 20 made of an elastic body such as metal.
It is composed of an exciter body 21 attached to one end for exciting the diaphragm 20, and a reflected wave absorber 22 attached to the other end of the diaphragm 20. The excitation body 21 is composed of a laminated piezoelectric body, and is electrically connected to a drive circuit 31 that outputs an electric signal of a frequency fr [kHz].

The reflected wave absorber 22 is the excitation body 21.
The impedance body 32 is made of a laminated piezoelectric material in the same manner as
Is electrically connected to the impedance body 32, the impedance body 32 consumes the vibration energy absorbed by the reflected wave absorber 22 to suppress the generation of a reflected wave at the reflection end of the diaphragm 20. With the above configuration, the vibration following the vibration excited by the diaphragm 20 of the electrode excitation device 2 is excited on the aperture electrode 10.

As shown in FIG. 2, the vibration plate 20 is provided with a substantially circular exposure hole 201, and toner particles can be supplied to the opening 11 of the aperture electrode 1 through the exposure hole 201. Has been done. The exposure hole 20
The diameter of 1 is determined to be sufficiently shorter than the wavelength of the traveling wave propagating through the diaphragm 20. For example, the diaphragm 20
When using a stainless steel plate with a thickness of 0.3 mm,
The diameter may be about 0.3 mm. In the diaphragm 20 having such a configuration, since the aperture electrode 10 vibrates following the vibration of the diaphragm 20, there is no problem such as noise. Furthermore, this exposed hole 201
Is a print range 202, which is a range in which the opening 11 used for the print operation is provided on the aperture electrode 10,
It is provided on the diaphragm 20 over a sufficiently wide range 203 in the width direction.

Next, the opening 11 is provided in the insulating layer 106 near the center of the aperture electrode 10.
The aperture rows 12 are arranged in a row. The reference electrode layer 107 is provided on the brush roller 103 side of the insulating layer 106. Further, the control electrode layer 108 is independently provided on the upper surface of the insulating layer 106 around each opening 11. The reference electrode layer 107 is grounded, and the plurality of control electrode layers 108 are
Each is connected to a signal source (not shown).

The aperture electrode 10 is provided on the opposite side of the brush roller 103 with the aperture electrode portion 1 interposed therebetween.
The counter electrode 112 is provided with 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 toner T passing 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 slot 117 is conveyed to the recording section 101. In the recording unit 101, the toner T is supplied to the supply roller 10 by the supply blade 111.
Pressed against 4 and loaded. 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 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. 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 cloud-shaped, passes through the exposure hole 201 of the diaphragm 20, and is supplied to the aperture electrode 10.

The flow of the toner T is modulated by the voltage applied to the control electrode layer 108 of the aperture electrode 10 from a signal source (not shown).

At this time, the drive circuit 31 is applied to the excitation body 21,
When an electric signal having a frequency fr is applied, the excitation body 21 expands and contracts, and the expansion and contraction causes the diaphragm 20 to excite a traveling wave propagating in the aperture array direction as described above. At this time, 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, the aperture array 12
Since a large vibration acceleration due to the traveling wave is generated at the position of, it cannot be attached. As a result, the toner flow is
The signal is modulated by the signal source (not shown) 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 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, referring to FIGS. 1 and 2, the operation of the aperture electrode section 1 constructed as described above will be described.

When the image is formed, the drive circuit 3 is attached to the excitation body 21.
When an electric signal having a predetermined frequency fr is applied from 1, the excitation body 21 expands and contracts at the frequency fr. The vibration excites the diaphragm 20, and when the vibration reaches the other end of the diaphragm 20, the reflected wave absorber 22 absorbs the vibration energy, and the impedance body 32 consumes the absorbed energy. Therefore, no reflected wave is generated at the reflecting end of the diaphragm 20. On the other hand, on the vibration plate 20, the boundary region 204 between the region where the exposure hole 201 is provided and the region where the exposure hole 201 is not provided is a so-called discontinuous region where the mechanical properties of the vibration plate 20 largely change. Therefore, the vibration energy incident from the exciter 21 is reflected to generate a standing wave.
The vibration excited above 0 becomes a vibration having an unstable and non-uniform amplitude distribution as schematically shown in FIG.

However, the exposed hole 201 of the diaphragm 20 has a printing area 2 in which the opening 11 of the aperture electrode 10 is provided.
02 is provided in a range 203 that is sufficiently wider than 02, and as described above, the size of the exposure hole 201 is sufficiently shorter than the wavelength of the traveling wave on the diaphragm 20, so that in the printing range 202. Is the exposure hole 201 or the boundary area 2
A uniform vibration is always excited without being affected by 04. Therefore, in the aperture electrode section 1,
Due to the traveling wave excited by the exciting device 2, sufficient vibration acceleration can be obtained in the vicinity of the aperture array 12, and as a result, it is provided on the aperture electrode 10 at any position within the printing range indicated by 202 in FIG. Since it is possible to obtain sufficient vibration acceleration even in the openings 11, the maximum vibration acceleration can be obtained at all the positions of the openings 11. Therefore, the toner does not adhere to the vicinity of the opening 11 of the aperture electrode 1, and as a result, it is possible to prevent the opening 11 from being clogged.

At this time, as described above in detail, since the opening is provided in a range sufficiently wider than the printing range, the nonuniformity or instability of the vibration in the boundary area has no influence on the printing result. Absent.

Further, the exposure hole 201 is formed in the diaphragm 2
If it is provided over the entire length of 0, the discontinuous area 204 due to the presence or absence of the exposure hole 201 does not exist on the diaphragm 20,
Further, it is obvious that the effect of the present invention can be improved.

In this embodiment, the shape of the exposed hole has been described by taking a circular shape as an example, but the same effect can be obtained even if the slit shape shown in FIG. 5 is adopted as the shape of the exposed hole. It is possible.

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 clear from the above description, according to the image forming apparatus of the present invention, the area where the exposed hole is formed on the diaphragm is the area where the opening is formed on the aperture electrode. By making the width wider, it is possible to always obtain a stable and uniform image regardless of unevenness or instability of vibration in the boundary region between the region where the exposed holes of the diaphragm are formed and the region where the exposed holes are not formed.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a configuration of a diaphragm of an electrode excitation device used in the image forming apparatus of the present invention.

FIG. 3 is a configuration diagram showing an embodiment of an image forming apparatus of the present invention.

4 is an explanatory diagram schematically showing a side surface of an aperture electrode portion and a vibration amplitude distribution on a diaphragm shown in FIG.

5 is a perspective view showing another configuration example of the diaphragm shown in FIG.

[Explanation of symbols]

 10 Aperture electrode 11 Opening 20 Vibration plate 201 Exposure hole

Claims (1)

[Claims] 1. An aperture electrode having an opening for modulating and controlling the flow of toner passing through the opening, and a diaphragm having an exposure hole attached to the aperture electrode and capable of exposing the opening. An image forming apparatus comprising: an image forming apparatus, wherein an area where an exposed hole is formed on the diaphragm is wider than an area where an opening is formed on the aperture electrode.