JPH0584961A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To easily control the modulation of toner flow without switching a strong electric field at a short cycle by using a vibration plate wherein are excited traveling waves advancing in two directions as a modulation control means of charged toner flow. CONSTITUTION:A waveguide plate 1 being a vibration plate has row waveguides 11, 12 provided in the X-direction, row exciting elements 211, 212 exciting traveling waves in the row waveguides 11, 12, row reflected wave absorbing elements 411, 412 absorbing reflected waves, column waveguides 21, 22... provided in the Z direction and column exciting elements 221, 222 exciting traveling waves in the column waveguides 21, 22.... Metal fixing parts 600 fix and hold many apertures 311, 312, 321, 322... provided at positions where the row reflected wave absorbing elements 421, 422 absorbing reflected waves, the line waveguides 11, 12 and the row waveguides 21, 22... cross each other.

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 which directly controls toner by a modulation control means to form an image on a recording medium. is there.

[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 is composed of a toner supply unit and a toner modulation control unit that controls the toner modulation. The toner supply means is means for supplying charged toner to the vicinity of the toner modulation control means.

Conventionally, in such an image forming apparatus,
The toner modulation control means was composed of an aperture electrode and a counter electrode. The aperture electrode is a control unit that modulates and controls the flow of toner from the toner supply unit, and includes an insulating layer having a large number of apertures or openings, and a first electrode 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 supply unit is
Recording is performed on a recording medium such as paper, which is controlled by an electric signal applied to the aperture electrode and the counter electrode.

[0004]

However, in the image forming apparatus as described above, since the toner flow is modulated and controlled according to the image signal by using the strong electric field formed by the aperture electrode and the counter electrode, It was necessary to switch this strong electric field at a cycle higher than the frequency of the image signal. Therefore, a high voltage power supply to generate a high electric field,
A switching circuit for switching the high-voltage electric signal is required, and as a result, the drive control circuit of the image forming apparatus is large and complicated.

The present invention has been made to solve the above-mentioned problems, and provides an image forming apparatus capable of easily controlling the modulation of toner without switching a strong electric field in a short period. It is an object.

[0006]

In order to achieve this object, the image forming apparatus of the present invention forms an image on a recording medium by allowing charged toner and modulated control of this toner to pass through an aperture electrode. In the image forming apparatus, a combination of an exciter that excites traveling waves propagating in two different directions to the aperture electrode and a vibration phase of the traveling waves propagating in the two directions is applied to the vicinity of the aperture of the diaphragm. A modulation control unit that modulates and controls the charged toner by controlling the vibration acceleration is provided.

[0007]

In the image forming apparatus of the present invention having the above structure, if the vibration phases of the traveling waves propagating from the two directions on the diaphragm are in phase at a predetermined aperture position, the charged toner is If the vibration phase of the traveling wave propagating from the two directions is the opposite phase, it passes through the aperture and is attracted onto the recording medium by the toner suction member to form a dot corresponding to this aperture on the recording medium. Since the toner does not pass through the aperture, the toner is not sucked onto the recording medium.

[0008]

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 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 section 101 comprises a toner supply section 2, a waveguide plate 1 which is a vibrating plate of toner modulation control means, and a counter electrode 112 which is a toner suction means. The toner supply unit 2 includes a toner carrier 202 that carries the charged toner T to the waveguide plate 1, and the toner carrier 20.
2 is a supply roller 104 for supplying the toner T to the toner.
Here, as a specific configuration of the toner transport body 202,
For example, the beat method described in the specification and drawings attached to the application of Japanese Patent Application No. 3-17785 proposed by the present inventors is easily conceivable. However, the toner conveying method adopted in the present embodiment is not limited to this. Any method such as a method using a conveyance roller does not impair the effects of the present invention. Therefore, the toner conveyance body 20 will be described here.
The detailed configuration of 2 is omitted.

Further, a supply blade 111 is provided in contact with the supply roller 104. The toner T is stored on the supply blade 111. And
The toner T is forcibly supplied to the supply roller 104 by the supply blade 111. Supply roller 1
04 and the supply blade 111 are covered by the case K.

The waveguide plate 1 includes the toner transport plate 20.
It is arranged in the vicinity of the end portion of 2 opposite to the supply roller 104.

Next, the structure of the waveguide plate 1 will be described with reference to FIG. In FIG. 1, a waveguide plate 1 is made of, for example, a polymer film such as polyimide, and has row waveguides 11 and 12 provided in the X direction and the row waveguides 11 and 1.
2 are provided at one end of the row waveguides 11 and 12 in the X direction for exciting a traveling wave, and row exciters 211 and 212 made of, for example, a polymer piezoelectric material such as PVDF, and the row waveguides. Row reflected wave absorbers 411 and 412 provided at the other ends in the X direction of 11 and 12 and configured to absorb a reflected wave made of a polymeric piezoelectric material such as PVDF, and like the row waveguides, are made of, for example, polyimide. Composed of polymer film,
The column waveguides 21, 22, ... Provided in the Z direction, and the Z of the column waveguides 21, 22, ... To excite a traveling wave in the column waveguides 21, 22 ,. The column excitation bodies 221, 222, ... Provided at one end in the direction and made of a polymeric piezoelectric material such as PVDF, and the column waveguide 2
Column reflected wave absorbers 421 and 422 provided at the other ends in the Z direction of the first and the second directions and configured to absorb the reflected waves made of a polymer piezoelectric material such as PVDF, the row waveguides 11 and 12, and the column waveguide A large number of apertures 311, 312, 321, 322, provided at positions where 21, 22, ...
.. and a fixing portion 600 made of metal for fixing and holding them.

The row reflected wave absorbers 411, 412 and the column reflected wave absorbers 421, 422, ... Are electrically connected to an impedance body (not shown) independently of each other. These impedance bodies (not shown) suppress the generation of reflected waves by consuming the vibration energy absorbed by the reflected wave absorber. That is, by adjusting the impedance, the impedance with respect to the vibration of the row and column waveguides 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, and the row waveguides 11 and 12 viewed from the row exciters 211 and 212 and the column exciters 221 and 222 ,. And the column waveguides 21, 22, ...
・ ・ Equivalent to infinite vibrations. Therefore, no reflected wave is generated, and only the traveling wave traveling in the + X direction is excited on the row waveguides 11 and 12, and
Only the traveling wave traveling in the + Z direction is excited on the column waveguides 21, 22, ....

As shown in FIG. 2, the row exciters 211 and 212 include an amplifier 511 and a switch circuit 521 in an oscillator 501 for generating an AC electric signal having a predetermined frequency.
Are electrically connected via. This switch circuit 5
Reference numeral 21 is connected to the CPU 54 and is configured to select the row waveguide for modulating the toner T by switching between the row waveguide 11 and the row waveguide 12 according to an image signal.
In addition, as shown in FIG. 3, the column excitation bodies 221, 222, ... Include an amplifier 512 and a switch circuit 52 in an oscillator 502 that generates an AC electric signal having a predetermined frequency.
It is electrically connected via a 2,180-degree phase shifter 532. The switch circuit 522 is connected to the CPU 54, and by switching the switches 61, 62, ... Of the switch circuit 522 according to an image signal,
It is configured to select whether to apply the output signal of the amplifier 512 as it is to the column excitation bodies 221, 222, ... Or to apply a signal obtained by rotating the vibration phase by 180 degrees through the phase shifter 532. ing.

The counter electrode 112 is provided on the opposite side of the waveguide plate 1 with the medium P on which an image is formed, with a predetermined space from the waveguide plate 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 is connected to the power source E2 (minus (-)). By applying this voltage, the apertures 311, 312, 321, 32 of the waveguide plate 1 are
The toner T that has passed through 2, ... 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 toner carrier 202. At this time, the toner T rubs while contacting the supply roller 104 and the toner transport body 202, and is charged positively (+), for example. The toner T, which is positively (+) charged, is carried by the toner carrier 202 and is carried to the position of the waveguide plate 1.

Here, for example, when it is desired to obtain a recording density of 300 DPI, since the dot size is about 80 μm at the maximum, it is necessary to reduce the inner diameter of the aperture to about 40 μm at the maximum. 10 μm
Since the size of the toner particles is about the same, the toner particles are deposited on the waveguide plate 1 by the image force or the like and cannot pass through the apertures unless a vibration acceleration of a predetermined value or more is applied to the vicinity of the apertures.

Here, the row waveguides 11 of the waveguide plate 1,
12 are excited by the row exciters 211, 212 and the column exciters 221, 222, ... On the column waveguides 21, 22 ,. The modulation of the charged toner T is controlled by selecting the vibration acceleration applied to the vicinity of the aperture by the combination of the vibration phases of the traveling waves propagating in the X direction and the Z direction.

In this way, the positively (+) charged toner T which has been modulated according to the image signal and passed through the aperture is
By the minus (-) power source E2 connected to the counter electrode 112, it 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 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 operation of the waveguide plate 1 will be described with reference to FIG. As described in detail above, the row exciter 211,
Reference numeral 212 is connected to the switch circuit 521. By switching the switch circuit 521 in accordance with an instruction from the CPU 54, progressive waves are sequentially excited in the row waveguides 11 and 12.

First, a traveling wave is excited in the row waveguide 11,
When the distribution of the vibration amplitude is in the state indicated by a1 in FIG. 4, the switch 61 is switched so that an electric signal not passing through the phase shifter 532 is applied to the column excitation bodies 221 and 222, and the column waveguide 21 and When a traveling wave having an initial amplitude distribution indicated by b1 in FIG.
At 1, the vibration phases of the traveling waves propagating in the X direction and the Z direction are opposite phases, so that the vibration amplitude becomes 0 near the aperture 311. At that time, since the vibration phases of the traveling waves propagating in the X direction and the Z direction are in the vicinity of the aperture 321, the vibration amplitude becomes maximum near the aperture 321. In such a state, the toner T
Cannot pass through aperture 311 while it can pass through aperture 321. As a result, the dots corresponding to the aperture 311 are not formed, and only the dots corresponding to the aperture 321 are formed on the medium P. On the contrary, when only the dots corresponding to the aperture 311 are formed without forming the dots corresponding to the aperture 321, the CP
Change the switch 61 by the command from U54,
When the row waveguide 11 has an amplitude distribution of a1, a signal via the phase shifter 532 is applied to the column excitation bodies 221 and 222, and the traveling waves having the amplitude distribution indicated by b2 are applied to the column waveguides 21 and 22. Should be excited. Thus, when the traveling wave is excited in the row waveguide 11,
By switching the switching circuit 522 for the vibration phase of the traveling wave excited in the column waveguides 21, 22, ... And selecting the phase difference from the vibration phase of the traveling wave on the row waveguide 11, the toner T is removed. The modulation is controlled by the apertures 311, 321, ... Provided on the row waveguide 11.

Next, the above operation is repeated when the traveling wave is excited in the row waveguide 12 by switching the switch 521, so that the toner T has the apertures 312, 322 provided on the row waveguide 12, and the toner T. Modulation is controlled by.

In this embodiment, as a method of exciting a traveling wave in the waveguide plate, a method of using an exciter made of a polymeric piezoelectric material and a reflected wave absorber has been described as an example, but the method is not limited to this. However, the method of the present invention does not impair the effect of the present invention even if it is a method capable of exciting a traveling wave.

Although a polymer material such as polyimide has been exemplified as a material for forming the waveguide plate, a material other than the polymer material can be used as long as it is an elastic body capable of exciting ultrasonic vibration.

Furthermore, in the present embodiment, the method of using an electric force as the means for attracting the toner onto the recording medium is illustrated, but a magnetic means using an electromagnet, for example, may be adopted. The effects of the present invention are not impaired.

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

[0030]

As is apparent from the above description, in the image forming apparatus of the present invention, since the traveling wave is used for the toner modulation control, the strong electric field is turned on and off in a short period.
An image can be formed on the recording medium by easily controlling the modulation of the toner without causing F. Moreover, since a high-voltage power supply that generates a high voltage is not required, it is easy to downsize the device.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a waveguide plate that is toner modulation control means.

FIG. 2 is an explanatory diagram schematically showing a drive circuit for exciting a traveling wave in a row waveguide.

FIG. 3 is an explanatory view schematically showing a drive circuit for exciting a traveling wave in a column waveguide.

FIG. 4 is an explanatory diagram schematically showing an amplitude distribution of a traveling wave excited in the waveguide plate shown in FIG.

5 is a configuration diagram showing a schematic configuration of an image forming apparatus using the toner modulation control means shown in FIGS.

[Explanation of symbols]

T toner 1 waveguide plate 311, 312, 321, 322, 331, 332, which is a vibration plate,
..Aperture 100 image forming apparatus

Claims (1)

[Claims] 1. In an image forming apparatus for forming an image on a recording medium by modulating and controlling charged toner to pass through an aperture, an exciting body for exciting traveling waves propagating in two different directions on a vibrating plate. And modulation control means for modulating and controlling the charged toner by controlling the vibration acceleration applied to the vicinity of the aperture of the diaphragm by the combination of the vibration phases of the traveling waves propagating in the two directions. Image forming apparatus.