JPH0664216A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To provide an image forming apparatus having a means capable of easily supplying toner particles to an aperture electrode by applying the momentum in the direction of the aperture electrode to toner particles in the opening parts of the vibration plate mounted on the aperture electrode in order to prevent the clogging of aperture. CONSTITUTION:A piezoelectric pump 201 consists of a first hole 2012 provided with a first valve 2011, a second hole 2014 provided with a second valve 2013 and a piezoelectric vibration plate 2015 and the first valve 2011 or the second valve 2013 is selectively opened and closed according to the vibration of the piezoelectric vibration plate 2015 to form an air stream to apply momentum to toner particles. The piezoelectric pump 201 is arranged so that the first hole 2012 comes to the position corresponding to the opening part 301 of a vibration plate 30.

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 shown in, for example, US Pat. No. 3,689,935. This image forming apparatus is composed of a toner supply unit, an aperture electrode, and a counter electrode. The toner supply means is means for supplying charged toner to the vicinity of the aperture electrode. The aperture electrode is a control unit that modulates and controls the toner supplied by the toner supply unit, and includes an insulating layer having a large number of apertures, and a first electrode layer provided on one surface of the insulating layer. The second electrode layer is 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 toner supplied by the toner supply means 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. It is formed.

When an image is formed by this image forming apparatus, there is a problem that the aperture of the aperture electrode is clogged with toner. 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, toner particles are deposited on the aperture electrode due to image force and the like, and as a result, the aperture electrode is clogged with the toner particles, and it is difficult to always obtain a stable image output. There was a problem.

Therefore, the present applicant has filed Japanese Patent Application No. 4-14061.
As described in the specification and drawings attached to the application, 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 the diaphragm to form an aperture electrode. We proposed a method to prevent toner particles from depositing on top. 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 such an image forming apparatus, the toner supplied by the toner supply unit is
It is configured so as to pass through an opening provided in the diaphragm and be supplied to the aperture electrode.

In the image forming apparatus of the above-mentioned system, as a toner supplying means, a cloud of charged toner is generated,
A toner supply system for supplying the toner cloud to the vicinity of the aperture electrode is generally used. For example, a system in which toner is carried on a brush roller and the elasticity of the brush forms the toner into a cloud, or a toner carrier and an aperture electrode are used. A method has been proposed in which an alternating electric field is applied between the two to make the charged toner cloud.

[0007]

However, in the case where the diaphragm is attached to the aperture electrode as described above, the thickness of the diaphragm depends on the thickness of the aperture electrode and the diameter of the toner particles due to its constitution. It should be much higher.

Further, when the toner supply system in which the toner is clouded and supplied is adopted as described above, the toner particles are sufficiently supplied in the vicinity of the vibrating plate. However, when the toner is clouded, the direction of the momentum of each toner particle becomes a random direction, so that only the toner having the momentum in the direction of the aperture electrode can approach the aperture electrode near the diaphragm. In this way, the toner that cannot approach the aperture electrode does not reach the electric field for modulation control by the aperture electrode.

As a result, in the image forming apparatus having the above structure, it is impossible to supply a sufficient amount of toner in the vicinity of the aperture electrode to output a clear image in a short time, which is very difficult to output an image. There was a problem that it took a long time.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to prevent toner particles from forming in the opening of a diaphragm attached to an aperture electrode for preventing clogging of the aperture. An object of the present invention is to provide an image forming apparatus having means capable of giving momentum in the direction of the aperture electrode.

[0011]

In order to achieve this object, an image forming apparatus of the present invention has a plurality of apertures,
An aperture electrode for modulating and controlling the flow of toner passing through those apertures; and a diaphragm attached to the aperture electrode and having an opening at a position corresponding to the aperture, further comprising the toner Is provided with an air flow generating means for giving momentum in the direction of the aperture electrode.

[0012]

In the image forming apparatus of the present invention having the above construction, the air flow generating means gives momentum in the direction of the aperture electrode to the toner particles supplied in the vicinity of the diaphragm so that the toner particles are sufficiently close to the aperture electrode. A large amount of toner can be easily supplied.

[0013]

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 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. As a result, in the recording unit 101, an image or the like is formed on the medium P such as plain paper that has entered through the insertion slot 117. After that, the image and the like on the medium are thermally fixed in the heat fixing unit 102. Further, the medium P is sent to the take-out port 118 via the guide 115.

The recording section 101 comprises an air flow generating means 2, an aperture electrode 1, a counter electrode 112 and a toner conveying means 4. As shown in FIG. 3, the aperture electrode 1 is provided with a large number of apertures 11 opening in the insulating layer 106 and arranged in a row to form an aperture row 12. Further, the reference electrode layer 107 is the insulating layer 1
No. 06 is provided on the air flow generating means 2 side. Further, the control electrode layer 108 is independently provided on the upper surface of the insulating layer 106 around the aperture 11. The reference electrode layer 107 is grounded, and the control electrode layers 108 are many.
Are respectively connected to signal sources (not shown).

Note that, in FIG. 4, each member such as the air flow generating means 2, the aperture electrode 1, the toner conveying means 4 and the like are schematically shown, and only their positional relationship is shown. The detailed configuration of the above is shown in FIGS.

Aperture electrode 1 constructed as described above
An electrode excitation device 3 is attached to this. The structure of the electrode excitation device 3 will be described with reference to FIG. The electrode excitation device 3 includes a diaphragm 30 made of an elastic material such as metal, an exciter 31 attached to one end for exciting the diaphragm 30, and an exciter 31 attached to the other end of the diaphragm 30. And a reflected wave absorber 32. The excitation body 31 is composed of a laminated piezoelectric body and is electrically connected to the drive circuit 33. The reflected wave absorber 32 is made of a laminated piezoelectric material like the excitation body 31, and is electrically connected to the impedance body 34. The impedance body 34 absorbs the vibration energy absorbed by the reflected wave absorber 32. Is consumed to suppress the generation of reflected waves at the reflection end of the diaphragm 30. Vibration following the vibration excited by the diaphragm 30 of the electrode excitation device 3 configured as described above is excited on the aperture electrode 1. Further, the vibration plate 30 is provided with a substantially circular opening 301, and toner particles can be supplied to the aperture 11 of the aperture electrode 1 through the opening 301.

Next, referring to FIG. 1, the air flow generating means 2
The configuration of will be described. The air flow generating means 2 is composed of a piezoelectric pump group 20 composed of a large number of piezoelectric pumps 201, 202, 203, .... Since the piezoelectric pumps 201, 202, 203, ... Have the same structure, the structure of the piezoelectric pump 201 will be described as an example based on FIG. 2A. This piezoelectric pump 201
Comprises a first hole 2012 provided with a first valve 2011, a second hole 2014 provided with a second valve 2013, and a piezoelectric vibrating plate 2015 composed of a piezoelectric bimorph vibrator. , And is electrically connected to the drive circuit 2016.

The first valve 2011 or the second valve 2013 is selectively opened / closed in accordance with the vibration of the piezoelectric vibrating plate 2015 to generate an air flow in the direction of arrow A. Further, the strength of the air flow is such that the toner particles that have moved to the vicinity of the aperture electrode 1 due to the generated air flow do not pass through the aperture 11 due to the electric field formed by the reference electrode 107 and the control electrode 108 of the aperture electrode 1. It is configured to be limited by the amplitude of the piezoelectric diaphragm 2015 so that passage can be selected. In the piezoelectric pump 201 configured as described above, the first hole 2012 is located at a position corresponding to the opening 301 of the vibration plate 30, and the second hole 2014 is located on the toner conveying unit 4 side. It is arranged to come to. The other piezoelectric pumps 202, 203, ... Forming the piezoelectric pump group 20 are also configured and arranged in the same manner as the piezoelectric pump 201.

As shown in FIG. 1 or 4, the toner conveying means 4 includes a conveying belt 41, a belt driving roller 42, a peeling means 5 for peeling toner from the conveying belt 41, and a conveying belt 41. And a supply roller 104 for supplying toner.
The supply blade 111 is provided in contact with. The toner T is stored on the supply blade 111. 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. Then, the toner T supplied from the supply roller 104 is transported to the vicinity of the piezoelectric pump group 20 by the toner transporting unit 4 configured as described above. The peeling means 5 comprises a vibrating body 51 and an exciting means 52 for exciting a traveling wave in the vibrating body 51. The detailed structure of the peeling means 5 is described in, for example, the specification and the drawing of Japanese Patent Application No. 3-241507, but any peeling means may be adopted in this embodiment. Since the effect of the present invention is not impaired at all, its details are omitted here.

As shown in FIG. 4, the aperture electrode 1 is provided above the air flow generating means 2, and the aperture electrode 1 is provided on the opposite side of the air flow generating means 2 with the aperture electrode 1 interposed therebetween. The counter electrode 112 is provided with a predetermined space therebetween. This space
The medium P that has entered through the insertion port 117 and has been sent via the guide 115 and the pair of auxiliary rollers 116 passes.
The counter electrode 112 is connected to the 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.

The operation of the image forming apparatus constructed as described above will be described with reference to FIG. Insertion slot 117
The medium P inserted from is conveyed to the recording unit 101.
In the recording unit 101, the toner T is supplied by the supply blade 111.
Is pressed against the supply roller 104 and carried. Then, the toner T is supplied onto the conveyor belt 41 by the supply roller 104. At this time, the toner T is in contact with the supply roller 104, rubs, and is, for example, positively (+) charged. The toner T, which is positively (+) charged, is conveyed by the conveyor belt 4
1 is supported. Then, by the rotation of the belt driving roller 42, the toner T carried on the conveyor belt 41 is conveyed to the vicinity of the piezoelectric pump group 20. At this time, a traveling wave is excited in the vibrating body 51 of the peeling means 5 by the function of the exciting means 52. Therefore, the conveyor belt 4
The toner T carried on the vicinity of the piezoelectric pump group 20 while being carried by No. 1 is separated from the carrying belt 41 by the traveling wave excited by the vibrating body 51.

At this time, for example, when a predetermined electric signal is applied from the drive circuit 2016 to the piezoelectric vibrating plate 2015 of the piezoelectric pump 201, the piezoelectric vibrating plate 2015 is deformed to the left in a convex shape. At this time, a flow of air from the outside to the inside of the piezoelectric pump 201 is generated. Next, the piezoelectric diaphragm 2
When an electric signal having a polarity opposite to the predetermined electric signal is applied to 015, the piezoelectric vibrating plate 2015 is deformed into a convex shape to the right, and an air flow from the inside of the piezoelectric pump 201 to the outside is generated. If this operation is continuously performed, an air flow is generated from the second hole 2014 of the piezoelectric pump 201 toward the first hole 2012, and this air flow causes the toner T to flow from the opening 301 of the diaphragm 30 to the aperture electrode 1. The toner T is given a momentum in the moving direction, and as a result, the toner T moves near the aperture electrode 1. Other piezoelectric pumps 202, 20
The operations of 3, ... Are the same as above.

Since the amount of momentum given to the toner T is limited by the piezoelectric vibrating plate 2015, the control electrode layer 10 of the aperture electrode 1 from a signal source (not shown).
The voltage applied to 8 can modulate the flow of toner T.

At this time, when an electric signal having a predetermined frequency fr is applied to the exciter 31 from the drive circuit 33, the exciter 31 expands and contracts at the frequency fr. The vibration plate 30 is excited by this vibration, and when this vibration reaches the other end of the vibration plate 30, as described above, the reflected wave absorber 32 absorbs the vibration energy, and the absorbed energy absorbs the vibration energy. Consumed in. Therefore, the diaphragm 30
At the reflection end of, no reflected wave is generated. As a result, only the traveling wave propagating in the length direction is excited on the diaphragm 30. At this time, even if the charged toner particles try to adhere to the vicinity of the aperture array 12 of the aperture electrode 1 due to image force or the like, a large vibration acceleration due to the traveling wave is generated at the position of the aperture array 12, Cannot be attached.

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 pressed against each other to be fixed. Since this fixing method 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 air flow generating means 2 configured as described above will be described with reference to FIGS. 1 and 2. As described above, the large number of piezoelectric pumps 201, 202, 203, ... Forming the piezoelectric pump group 20 all have the same structure and operate in the same manner.
01 will be exemplified to explain the operation. Piezoelectric pump 201
When a predetermined electric signal is applied to the piezoelectric vibrating plate 2015 from the drive circuit 2016, the piezoelectric vibrating plate 2015 is deformed into a convex shape to the left as shown in FIG. 2B. At this time,
The first valve 2011 provided in the first hole 2012 is closed and the second valve 2013 provided in the second hole 2014 is opened. As a result, the arrow B pointing from the outside to the inside of the piezoelectric pump 201
A directional air flow is generated, and the toner flows on the air flow and is conveyed immediately below it by the conveyor belt 41. The toner T separated from the conveyor belt 41 by the separating device 5 is sucked into the piezoelectric pump 201.

Next, when an electric signal having a polarity opposite to the predetermined electric signal is applied to the piezoelectric vibrating plate 2015, as shown in FIG.
As shown in, the piezoelectric vibrating plate 2015 is deformed into a convex shape to the right. At this time, contrary to the above, the first valve 2011 provided in the first hole 2012 is opened and the second valve 2013 provided in the second hole 2014 is closed, so that the arrow from the inside of the piezoelectric pump 201 to the outside is shown. A flow of air in the C direction is generated, and the toner T sucked in the piezoelectric pump 201 is discharged from the first hole 2012 by riding on this flow of air.

If the above operation is continuously performed, the piezoelectric pump 201 continuously gives the toner T a momentum in the direction of the arrow A from the toner conveying means 4 shown in FIG. Can be done. Here, the magnitude of the momentum is limited so that the toner that has moved to the vicinity of the aperture electrode 1 can be modulation-controlled by the electric field formed by the aperture electrode 1, as described above. As a result, the toner T transported by the toner transporting means 4 to the position immediately below the air flow generating means 2 becomes the aperture electrode 1.
Since it moves to the vicinity of,
A sufficient amount of toner is always stably supplied.

In this embodiment, a piezoelectric pump is used as an example of the air flow generating means. However, as long as the air flow can be generated in the vicinity of the diaphragm in the direction of the aperture electrode, for example, a method using a fan, The same effect as that of the present invention can be obtained even with other air flow generating means.

Further, as the structure of the piezoelectric pump, the structure having two valves and the piezoelectric vibrating plate has been exemplified, but the structure is not limited to the structure of the present embodiment, and it is possible to generate an air flow. Therefore, the effect of the present invention is not impaired regardless of the configuration.

Further, the electrode exciting device, the aperture electrode, the toner conveying means, and the peeling means for peeling the toner from the conveying belt are not limited to the method described in detail in this embodiment, and the same effect can be obtained. Any other structure may be used as long as the structure has

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

[0036]

As is apparent from the above description, the image forming apparatus of the present invention is provided with the air flow generating means for giving the charged toner a momentum in the direction of the aperture electrode. Not affected by the diaphragm,
Since a sufficient amount of toner can always be moved to the very vicinity of the aperture electrode, it is possible to easily obtain a clear image stably for a long time.

[Brief description of drawings]

FIG. 1 is a diagram showing an arrangement configuration of an air flow generating unit and a toner conveying unit used in an image forming apparatus of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of a piezoelectric pump used in the image forming apparatus of the present invention.

FIG. 3 is a perspective view showing a configuration of an electrode excitation device used in the image forming apparatus of the present invention.

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

[Explanation of symbols]

 1 Aperture Electrode 2 Air Flow Generation Means 11 Aperture 30 Vibration Plate 301 Opening

Claims (1)

[Claims] 1. An aperture electrode having a plurality of apertures, which controls modulation of a toner flow passing through the apertures, and an aperture electrode attached to the aperture electrode and provided at a position corresponding to the aperture. An image forming apparatus comprising a vibrating plate, wherein the image forming apparatus is provided with an air flow generating unit that gives momentum to the toner in the direction of the aperture electrode.