JPH06238943A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device which can obtain an image output without any fog at high speed. CONSTITUTION:A toner layer comes to have a charge distribution wherein a toner layer borne on a toner carrier increases in a charged quantity from a lower layer toward a front layer by giving vibration to a layer thickness- controlling blade 133 with an ultrasonic vibrator 134. A cloud which is high in the charged quantity and free from reversed polarity-charged toner can be generated.

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 applied to a copying machine, a printer or the like.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus, there has been proposed an image forming apparatus comprising a toner supply means and a toner flow control means. The toner carrier is a means for carrying charged toner and supplying the charged toner in the vicinity of the toner flow control means. The toner flow control unit is a unit that modulates the flow of the charged toner by applying an image signal to the toner flow control unit. With the above structure, the modulated toner can be copied onto a support such as plain paper to form an image or the like.

However, in the image forming apparatus having the above-mentioned structure, it is difficult to obtain a practical printing speed with a low-voltage image signal, and in order to solve this, a method of supplying cloud-shaped toner to the aperture is actually used. It is proposed in the specification and the drawings attached to Japanese Patent Application No. 3-38903. The outline will be described below with reference to FIG. 7.

In the toner supply device 20, the toner 26 is accommodated in a toner case 21 whose upper end is opened, and a nylon roller 22 having an annular nylon body mounted on the surface of a metal core and a small-diameter supply roller 23 are provided. , Are arranged so that they are in contact with each other and the rotation axes are parallel to each other. Further, at the top of the surface of the nylon roller 22, a metal contact member 24 having a rectangular cross section has a side surface 24a on which the roller 2 is attached.
It is arranged so as to be substantially perpendicular to the toner carrying surface of No. 2 and the corners of the lower end thereof are in contact with each other. Furthermore, a guide plate 25 that guides the flow of the toner 26 from immediately below the aperture 6 of the aperture electrode body 1 to the vicinity of the contact member 24.
Has been extended. The metal core of the nylon roller 22 and the contact member 24 are grounded.

In the feeding device configured as described above,
The rotation of the nylon roller 22 and the supply roller 23 in the direction of the arrow causes the toner 26 in the toner case 21 to be negatively charged by friction with the nylon roller 22, and is carried on the surface of the nylon roller 22. The toner 26 carried on the contact member 2 is rotated by the rotation of the nylon roller 22.
4 is conveyed. Here, the toner 26 on the nylon roller 22 collides with the side surface 24 a of the contact member 24,
It is flipped back by this reaction force to form a cloud, and the guide plate 25
Is supplied to the lower side of the aperture 6 of the aperture electrode body 1 from one end of the.

[0006]

However, although the above-mentioned image forming apparatus has been considerably improved in controllability of the printing speed and the toner flow, the fog of the printed image is still large, and the printing speed of the practical level is not achieved. I couldn't get it. The reason is that the influence of the charge distribution in the toner layer carried on the toner carrier is large.

Specifically, in the conventional apparatus, the toner charge is mainly the frictional charge between the toner carrier and the toner. Therefore, in the toner layer, from the lower layer in contact with the toner carrier to the upper layer, the broken line in FIG. The problem was that the charge amount distribution was such that the charge amount decreased as shown in FIG. Incidentally, FIG.
The horizontal axis represents the position in the toner carrier layer in the normal direction of the carrier with the surface of the carrier as the origin, and the vertical axis represents the charge amount of the carried toner per unit weight. for that reason,
In the contact member, not all of the toner layer formed on the carrier is formed into a cloud, but the toner present on the surface layer, having a low charge amount, and the toner having the opposite polarity is likely to be present, is supplied to the aperture. It was mainly supplying unsuitable toner. When such a toner with a low charge amount is supplied to the aperture, the controllability due to the control electric field formed in the aperture deteriorates, and not only the print speed does not increase, but also the momentum of the cloud easily passes through the aperture. It also causes image fogging. Further, when a toner charged to the opposite polarity is used, the toner behaves in exactly the opposite manner to the correctly charged toner, causing image fog and significantly deteriorating the image quality.

To be precise, the abutting member is formed by applying a thin nylon coat to a metal cored bar, and is positively (+) charged by rubbing the negatively charged toner. However, in this state, the amount of charge of the nylon coat is saturated and the charging ability for the toner is reduced, so the surface of the nylon coat is rubbed with an antistatic brush. Although there was no problem, the surface potential of nylon was quite positive (+). Therefore, the toner of the lower layer, which has a high charge amount, is electrostatically strongly attached to the nylon coat, which makes it more difficult to form a cloud.

Further, even if the nylon coat of the carrier is stopped and it is considered as a metal roller, only the toner having a large charge amount in the lower layer strongly adheres due to the image force acting.

However, if the contact member is strongly pressed against the carrier, even the toner in the lower layer can be clouded, but this time, the wear of the contact member and the carrier is too severe. It becomes completely lacking in durability. Therefore, in order to obtain practical durability, the toner layer on the carrier is not entirely clouded by the abutting member, but is sheared in the toner layer and left on the carrier as much as possible. It was necessary to make a contact with a stable contact pressure.

If a layer regulation blade is used instead of the supply roller to regulate the toner carrying thickness to about twice the toner particle size, only highly charged toner can be carried, but it has a strong adhesive force and a carrying layer. Since it is thin, a strong contact pressure is required, and it is difficult to maintain the durability of the contact member and the carrier. Therefore, we tried to suppress the contact pressure of the contact member and increase the peripheral speed of the toner carrier to secure the cloud amount. However, the vibration of the contact member becomes severe and the cloud is efficiently and stably generated. I couldn't do that.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus capable of obtaining an image output without fog at high speed.

[0013]

In order to achieve this object, an image forming apparatus of the present invention includes a toner flow control means for controlling the flow of charged toner flying based on image data and the toner. And a toner supply unit that carries the toner and supplies the toner to the toner flow control unit, and a regulation unit that is in pressure contact with the toner supply unit and regulates the amount of the toner that is carried. A vibration applying unit that applies vibration to the restricting unit is provided.

[0014]

In the image forming apparatus of the present invention having the above structure, the vibration applying means applies the vibration to the regulating means.

[0015]

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

In FIG. 1, a toner jet recording apparatus 1
Reference numeral 00 includes a recording unit 101 and a heat fixing unit 102. An insertion port 117 and an ejection port 118 are provided on the side of the toner jet recording apparatus 100. Then, in the recording unit 101, the insertion port 11
An image or the like is recorded on a support P such as plain paper that has entered from 7. An image or the like is fixed on the support P in the heat fixing section 102. Further, the support P is sent to the take-out port 118.

The recording unit 101 includes an aperture electrode body 1
And a toner supply unit 103 arranged below the counter electrode 112 and a counter electrode 112 arranged above the aperture electrode body 1. In FIG. 2, the aperture electrode body 1 sandwiches an insulating layer 106 in which aperture rows 12 are arranged at equal intervals in a row and sandwiches an insulating layer 106, and a lower layer electrode 107 entirely laminated on the lower layer and an aperture layer on an upper layer. Has a three-layer structure including the upper electrode 108 that is independently laminated.
Further, the large number of upper layer electrodes 108 are connected to the large number of signal sources L shown in FIG.

In FIG. 2, the excitation device 2 for exciting the aperture electrode body 1 is composed of an excitation body 21 and a reflection absorber 22 which are attached to both ends of the aperture electrode body 1 in the X direction. The excitation body 21 has a resonance frequency of fr [kHz].
Frequency range fr
It is electrically connected to a drive circuit 31 that outputs an electric signal of [kHz].

The reflected wave absorber 22 is the excitation body 21.
A Langevin oscillator and is electrically connected to the impedance body 32.
Is to suppress the generation of reflected waves by consuming the vibration energy absorbed by the reflected wave absorber 22. That is, the impedance with respect to the vibration of the aperture electrode body 1 on the reflected wave absorber side is made variable by adjusting the impedance body. Therefore, the impedance (resistance value,
By appropriately adjusting the reactance value), impedance matching is performed, and the aperture electrode viewed from the side of the exciter body 21 becomes equivalent to one that continues infinitely with respect to vibration. Therefore, the reflected wave is not generated, but only the traveling wave. Therefore, the generation of standing waves can be suppressed.

In FIG. 1, the toner supply means 103 located below the aperture electrode body 1 includes a rotatable metallic gap roller 105 disposed below the aperture array 12 with a gap of about 1 mm. There is a foaming sponge roller 111 of silicon rubber, which is arranged on the right side and is rotatable clockwise, and both rollers have a carrying sleeve 104.
Is hung. The material of the carrying sleeve 104 is
For example, it is made of nickel with a thickness of about 50 μm and has a surface roughness R
It is processed to a maximum of 1 to 5 μm.

The rotatable tension roller 110, which is disposed below the gap roller 105 and inside the carrying sleeve 104, presses the bearing portion of the tension roller 110 by a coil spring 122 to give the carrying sleeve 104 an appropriate tension. ing. A counter blade 131 is attached to the right of the sponge roller 111 so as to be rotatable around a support shaft 136 as a fulcrum. Counter blade 1
A stainless plate having a thickness of, for example, about 0.1 mm is attached to the tip of the gap roller 31.
5 and the sponge roller 111, the carrying sleeve 1
The surface of 04 is pressed by a torsion coil spring 132 with a constant pressure.

An agitator 130 rotatable counterclockwise is arranged on the right side of the sponge roller 111 so that the toner can be supplied to the carrying sleeve 104 mounted on the sponge roller 111 while preventing aggregation of the toner. It has become. Further, below the sponge roller 111, a layer thickness regulating blade 133 is arranged in contact with the carrying sleeve 104. FIG. 3 shows a perspective view of the layer thickness regulating blade 133, and the bent portion on the right side of the layer thickness regulating blade 133 is
Its lower end is rotatably fixed to the case K,
On the other hand, an ultrasonic vibrator 134 fixed to the case K is attached to the left bent portion, and the layer thickness regulating blade 13
3 can be vibrated in the longitudinal direction of the sponge roller 111. As the vibration condition, for example, frequency 1 to
The amplitude is about 20 to 30 μm (pp) at 5 kHz.
The layer thickness regulating blade 133 is brought into contact with the carrying sleeve 104 in a state where the vicinity of the front side bent portion is bent downward, and the contact pressure uses elasticity due to the bending, and the linear pressure is 50 to 1
It is about 00 gf / cm.

All of these are grounded and covered with a case K. In the right part of the case K where the agitator 130 is arranged, for example, a styrene-acrylic nonmagnetic insulator having a particle size of 6 to 12 μm is used. Negatively charged toner T
Is stored.

Above the aperture electrode body 1, there is a predetermined space with the aperture electrode body 1 and the counter electrode 11 is provided.
Two are provided. The support P that has entered the space through the insertion opening 117 and has been sent through the guide 13 and the pair of auxiliary rollers 119 passes through this space. A paper pressing spring 113 presses the lower surface of the counter electrode 112 with a constant pressure,
The support P passing therethrough is conveyed in close contact with the counter electrode 112. The counter electrode 112 is connected to the power source E (plus (+)). By applying this voltage, the toner T having passed through the aperture 11 of the aperture electrode body 1 is moved and adsorbed on the medium P.

The heat fixing section 102 has a heat roller 115 having a halogen heater 114 which is a heat source fixed inside.
And a press roller 116. And
The medium P is the heat roller 115 and the press roller 116.
It is arranged so that it can pass between.

Next, the operation of the toner jet recording apparatus will be described with reference to FIG. The medium P inserted from the insertion port 117 is conveyed to the recording unit 101. In the recording unit 101, the toner T stored near the agitator 130 is
While being agitated by the rotation of the agitator 130, the agitator 130 is supplied to the vicinity of the carrying sleeve 104 that rotates along with the sponge roller 111 that rotates clockwise. The supplied toner T adheres to the carrying sleeve 104 and is conveyed. However, when reaching the layer thickness regulating blade 133, the carried toner T is regulated in its layer thickness and at the same time charged with friction. In a thin layer charging mechanism using a general layer thickness regulating blade, the toner and the carrier are mainly triboelectrically charged to exchange charges. However, the layer thickness regulating blade 133 of the present embodiment uses the ultrasonic vibration. Since the vibration is imparted by the child 134, the toner T is absorbed by the layer thickness regulating blade 133.
Friction charging with is the main.

Therefore, the toner layer, which has passed through the layer thickness regulating blade 133 and is regulated to about 5 layers, has a distribution in which the surface layer has a higher charge amount than the lower layer as shown by the solid line in FIG. 4, and is further conveyed. Then, it reaches the gap roller 105, further passes under the aperture electrode body 1 , and reaches the contact portion of the counter blade 131. The counter blade 131 internally shears the toner carrying layer to generate a cloud around the toner T having a high charge amount and no reverse polarity on the surface layer thereof. At this time, since the counter blade 131 does not come into direct contact with the carrying sleeve 104, the durability of both is high. The generated cloud flies toward the space between the aperture electrode body 1 and the gap roller 105 with its force. Since the distance between the electrode body 1 and the carrying sleeve 104 is narrowed toward the left, the flight range of the cloud flying there is gradually narrowed, and the aperture array 12
Most of the clouds that have reached the vicinity are supplied only as a motion vector in the left direction parallel to the aperture electrode body 1.

At this time, the aperture 1 for generating the toner flow
In No. 1, a positive (+) voltage is applied to the upper layer electrode 108 by the signal source L to internally form an electric field toward the upper layer electrode. Then, the negative (-) charged toner T
Generates a toner flow through the aperture 11 by Coulomb force. Also, by controlling this voltage,
The toner flow is modulated.

On the other hand, in the aperture that does not generate the toner flow, the signal source L applies a minus (-) voltage to the upper layer electrode 108 to form an electric field inside toward the lower layer electrode. Therefore, the negative (-) charged toner T
Receives Coulomb force that keeps him away from aperture 11. As described above, since the motion vector in the aperture penetrating direction of the cloud supplied to the aperture is almost killed, the momentum of the flight is excessive and the aperture 1 is irrelevant regardless of the control electric field.
The image fogging does not occur because the image does not pass through 1.

However, in reality, the toner T easily adheres to the aperture electrode body 1 and often clogs the aperture 11. First, the toner T is applied to the lower electrode 107 around the aperture.
The toner adheres to the toner, and then the toner adheres to the adhered toner, and eventually a bridge of toner covering the aperture is formed to block the aperture, so that the toner flow cannot be generated. Therefore, the exciting device 2 may apply a traveling wave to the aperture electrode body 1 to shake off the adhered toner so that a toner bridge is not formed.

The minus (−) charged toner T that has passed through the aperture 11 is directed toward the counter electrode 112 to which a voltage larger than the voltage applied to the upper layer electrode 108 in the plus (+) direction is applied by the power source E. To fly. The toner T is guided by the guide 13 and the pair of auxiliary rollers 1
19 is sucked by the support P.

After that, the support P is conveyed to the heat fixing section 102. Then, at this place, the image on the support P is fixed by being pressed by the heat roller 115 and the press roller 116 while being heated. Since this fixing method is a general method, detailed description is omitted. Then, finally, the image-formed support P is conveyed to the take-out port 118 and taken out.

In this embodiment, the nickel sleeve is used as the toner carrying means, but a roller-shaped carrying body may be used, and various modifications can be made without departing from the scope of the present invention. .

A second embodiment for supplying a toner carrying carrier by directly contacting the aperture will be described with reference to the drawings.

FIG. 5 is a diagram showing an outline of the image forming apparatus of the second embodiment, which has a cylindrical shape with a gap of 1 mm above the aperture electrode body 1 as the toner flow control means. A back electrode roller 222 is rotatably arranged on a chassis (not shown), and is configured to be able to convey the support P inserted into the gap. Further, a toner supply device 103 is disposed below the aperture electrode body 1 along the longitudinal direction of the aperture electrode body 1, and further, a support body conveyed by the back electrode roller 222. The fixing device 102 is disposed at the destination of P.

Next, the respective components will be described in detail. In the toner supply device 103, the toner case 211 which also serves as a housing of the entire device, and the toner case 21 thereof.
1, the toner T accommodated in the first unit, the supply roller 212, the toner carrying roller 214, and the toner layer thickness regulating blade 13
3 and an ultrasonic transducer 134. Here, the toner carrying roller 214 carries the toner T,
The feeding roller 212 feeds the toner T to the toner carrying roller 214.

In the aperture electrode body 1, as shown in FIG. 6, a plurality of apertures 11 having a diameter of 100 μm are formed in a row on a 25 μm-thick polyimide insulating sheet 106, and the control electrodes 108 are provided above each aperture 11. Is formed with a thickness of 1 μm. Then, the aperture electrode body 1
As shown in FIG. 5, the control electrode 108 is opposed to the support P side, and the insulating sheet 106 is arranged so as to contact the toner on the toner carrying roller at the aperture position.

A control voltage applying circuit L is connected between the control electrode 108 and the toner carrying roller 214. The control voltage application circuit L is configured to apply a voltage of 0 V or +50 V to the control electrode 108 based on the image signal.

Further, a DC power source E is connected between the back electrode roller 222 and the toner carrying roller 214, and this DC power source can apply a voltage of +1 kV to the back electrode roller 222. It has become.

Next, the operation of the image forming apparatus configured as described above will be described.

First, the toner T sent from the supply roller 212 is rubbed against the toner support roller 214 by the rotation of the toner support roller 214 and the supply roller 212 in the direction of the arrow shown in FIG.
Carried on top. The carried toner T is thinned and charged by the layer thickness regulating blade 133 and the ultrasonic vibrator 134, and then is conveyed toward the aperture electrode body 1 by the rotation of the toner carrying roller 214. The operations of the layer thickness regulating blade 133 and the ultrasonic transducer 134 are the same as those described in the first embodiment.

The toner on the toner carrying roller 214 is rubbed by the insulating sheet 106 of the aperture electrode body 1 and supplied below the aperture 11.

Here, in accordance with the image signal, a voltage of +50 V is applied from the control voltage applying circuit 8 to the control electrode 108 corresponding to the image portion. As a result, in the vicinity of the aperture 11 corresponding to the image portion, due to the potential difference between the control electrode 108 and the toner carrying roller 214, the control electrode 1
A line of electric force is formed from 08 toward the toner carrying roller 214. As a result, the negatively charged toner receives an electrostatic force in the direction of higher potential, and the toner carrying roller 21
4 passes through the aperture 11 and is drawn out to the control electrode 108 side. The toner T pulled out further flies toward the support P due to the electric field formed between the support P and the aperture electrode body 1 by the voltage applied to the back electrode 222, and on the support P. To form pixels.

Further, the control electrode 10 corresponding to the non-image part
A voltage of 0V is applied to 8 from the control voltage applying circuit L. As a result, the toner carrying roller 214 and the control electrode 10
Since an electric field is not formed between the toner carrying rollers 8, the toner T on the toner carrying roller 214 does not receive the electrostatic force, and therefore does not pass through the aperture 11.

Further, the support P has toner T on its surface.
Thus, while one row of pixels is being formed, one pixel is fed in the direction perpendicular to the aperture row. Then, by repeating the above process, a toner image is formed on the entire surface of the support P. After that, the formed toner image is fixed on the fixing device 102.
It is fixed on the support P by.

In the image forming apparatus constructed as described above, if the insulating toner is used, the toner carrying roller 21
4 and the control electrode 108 are kept insulative, and the aperture 1
1 does not cause dielectric breakdown.

The present invention is not limited to the embodiments described in detail above, and various changes can be made without departing from the spirit of the invention.

For example, although the control voltage of the aperture corresponding to the non-image portion is set to 0V in the above embodiment, this may be a negative voltage. In this case, an image with less fogging can be obtained. Further, in the above embodiment, the aperture electrode body is used as the toner flow control means, but it is also possible to use, for example, a stitched electrode body as described in JP-A-1-503221.

[0049]

As is clear from the above description,
The image forming apparatus of the present invention is pressed against the toner supply unit,
Since the regulation means for regulating the amount of toner to be carried and the vibration giving means for giving vibration to the regulation means are provided, whether the toner layer carried on the toner carrier is closer to the surface layer than the lower layer The charge distribution is increased, the amount of charge is high, and the toner cloud in which the toner charged to the opposite polarity is not mixed is generated, and the image output can be performed at high speed and without fogging.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment embodying the configuration of an image forming apparatus of the present invention.

FIG. 2 is a perspective view showing a configuration of a toner flow control unit mounted in the image forming apparatus of the present invention.

FIG. 3 is a perspective view showing a configuration of a regulation unit mounted on the image forming apparatus of the present invention.

FIG. 4 is a graph showing a charge amount distribution in a toner layer formed on a carrier of the present invention and a conventional image forming apparatus.

FIG. 5 is a diagram showing a configuration of a second embodiment of the image forming apparatus of the present invention.

FIG. 6 is a perspective view showing a configuration of an aperture electrode body used in a second embodiment of the image forming apparatus of the invention.

FIG. 7 is a diagram showing a configuration of a conventional image forming apparatus.

[Explanation of symbols]

 1 Aperture Electrode Body 11 Aperture 103 Toner Supply Means 104 Carrying Sleeve 133 Layer Thickness Control Blade 134 Ultrasonic Transducer T Toner

Claims (1)

[Claims] 1. A toner flow control means for controlling a flow of flying charged toner based on image data, and a toner supply means for carrying the toner and supplying the toner to the toner flow control means. An image forming apparatus comprising: a regulating unit that regulates the amount of toner carried by being pressed against the toner supply unit; and an image forming apparatus that includes a vibration imparting unit that imparts vibration to the regulating unit. apparatus.