JPH04238050A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To provide an inexpensive image forming apparatus using a toner supply means easy to control aperture passage and to prevent the abrasion and damage of the toner feed belt constituting the toner supply means. CONSTITUTION:A gap is provided between a toner feed belt 26 having toner supported thereon and an ultrasonic vibrator 27 and the toner feed belt 26 is vibrated through air.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to copying machines, printers,
The present invention relates to an image forming apparatus that can be used for plotters, facsimile machines, etc.

0002

2. Description of the Related Art Conventionally, an image recording apparatus which controls the passage of toner particles through an aperture by applying an image signal to an electrode having an aperture and obtains an image on a support is US Pat.
689935.

This proposal consists of a reference electrode made of a continuous conductor on one side with an insulator layer in between, and a control electrode made of a plurality of conductors insulated from each other on the other side. an aperture electrode body having at least one row of apertures extending through the three layers for each control electrode; means for selectively applying a potential between the control electrode and a reference electrode; and means for moving the support and the aperture electrode relative to each other to position the support in the particle flow path.

As a means for supplying charged toner particles to the vicinity of the aperture in this method, Japanese Patent Laid-Open No. 62-24
No. 8662 discloses a method in which toner is carried on the surface of a toner carrying roller and the toner is conveyed to the vicinity of an aperture by rotation of the roller, and JP-A-58-44457 discloses a method in which an alternating electric field is applied between a toner conveying member and an aperture electrode. Japanese Patent Application Laid-Open No. 114974/1983 proposed a method in which toner particles are conveyed in an air stream by applying a charged toner in the form of a cloud.

[0005]

[Problems to be Solved by the Invention] However, in the case where a carrier roller is used to supply toner particles near the aperture as described above, forces such as mirror image force and van der Waals force that cause the toner to adhere to the carrier roller are difficult to overcome. is relatively large. Therefore, a strong electric field is required to peel the toner from the carrier roller and pass it through the aperture, and therefore a high voltage power source is required.

Furthermore, devices that require an alternating electric field require a high-voltage AC power supply, and the alternating electric field disturbs the control electric field that controls the passage of toner through the aperture, resulting in unclear images and expensive equipment. There are drawbacks. Those that utilize airflow require a device such as a compressor to generate the airflow, and have the disadvantage that the entire image forming apparatus is complicated and expensive.

The present invention has been made to solve the above-mentioned problems, and its first purpose is to eliminate the need for expensive equipment such as a high-voltage AC power supply or compressor, and to
It is an object of the present invention to provide an inexpensive image forming apparatus by using a toner supply means that can easily control passage through an aperture.

A second purpose is to prevent wear and damage of the toner conveying belt constituting the toner supply means.

[0009]

[Means for Solving the Problems] In order to achieve this object, an image forming apparatus of the present invention includes a toner conveying belt disposed to face an aperture, and a surface of the toner conveying belt that opposes the aperture. and a means for causing ultrasonic vibration, and a gap is provided between the toner conveying belt and the means for causing ultrasonic vibration.

0010

According to the present invention having the above structure, the charged toner is carried on the toner conveying belt and conveyed to the surface facing the aperture. Since the surface of the belt located at the surface facing the aperture is vibrated by the ultrasonic vibration means through the air, the toner carried on the belt surface is subjected to force due to the vibration acceleration of the belt surface.

[0011] Therefore, the toner conveying belt does not suffer from wear or damage, and the toner has a mirror image force with the belt.
Freed from adhesion forces such as van der Waals forces and electrostatic forces, it moves dynamically on the belt, and the passage of toner through the aperture can be controlled by a relatively small electric field.

0012

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

FIG. 1 is a sectional view of a printing device embodying the present invention. As shown in detail in FIG. 2, the aperture electrode body 1 has a reference electrode 3 on the toner supply source side of the insulating layer 2 and a control electrode 4 on the support 10 side. A large number of apertures 6 penetrating through the support body 10 are formed in a line corresponding to the width of the support body 10.

In FIG. 1, a support 10 is conveyed by a support conveyance roller 14 on the control electrode 4 side of the aperture electrode body 1, and a back electrode 11 is disposed in contact with the back surface of the support 10. A fixing device 13 is installed at the conveyance destination 10.
is located. Each control electrode 4 is connected to a control voltage drive circuit 8 that generates a voltage based on an image signal. The back electrode 11 is connected to a negative high voltage power source 12.

On the reference electrode side of the aperture electrode body 1, a toner conveyance belt 26 is wound between the drive roller 20 and the backup roller 24, and on the back side of the toner conveyance belt 26 opposite to the aperture electrode body 1. , the gap between the ultrasonic vibrator 27 and the toner conveying belt 26 is 0.
．． It is placed at a distance of 1 to 10 mm. This gap is set larger than the amplitude range of the ultrasonic vibrator 27, and the ultrasonic vibrator 27 is connected to the toner conveying belt 2.
It will be in a position where it does not touch 6. An electrostatic brush 31 is arranged upstream of the ultrasonic vibrator 27.

Toner 22 is stored in the toner case 21 , and the toner 22 is carried on a carrying roller 30 by a supply roller 23 . The carrying roller 30 and the toner conveying belt 26 are provided at a position where a gap a of 0.1 to 0.4 mm is created.

The operation of the above-described configuration will be explained in detail below.

As the drive roller 20 rotates in the direction of the arrow, the toner conveying belt 26 rotates between the backup roller 24 and the drive roller 20, and as the supply roller 23 rotates in the direction of the arrow, the toner 22 is rubbed against the carrier roller 30.
After being positively charged by friction, it is carried on a conveyor belt by electrostatic coating using a high-voltage power source.

Since the toner 22 carried on the toner conveying belt 26 is electrostatically applied, it is only positively charged toner 22, so it is easy to control with electrodes, and there is no space between the toner 22 and the toner conveying belt 26. Since no pressure is generated, there is no adhesion.

The supported toner 22 is conveyed toward the opposite surface of the aperture electrode body 1, and the conveyor belt 26 is neutralized by a neutralizing brush 31 from the back side of the conveyor belt 26 on the upstream side of this position. The surface of the conveyor belt 26 is vibrated through the air by the ultrasonic vibrator 27 at a position facing the aperture electrode body 1 . Therefore, the conveyor belt 26
The toner 22 supported on the conveyor belt 26 receives a force due to the vibration acceleration of the conveyor belt 26 and is released from adhesion forces such as mirror image force, van der Waals force, and electrostatic force with the conveyor belt 26 .

At this time, since the surface of the toner conveying belt 26 is vibrated by the ultrasonic vibrator 27 through the air, the toner conveying belt 26 is not worn or damaged by the ultrasonic vibrator 27.

On the other hand, at this time, the control electrode 4
When a negative voltage is applied to the aperture 6 of the applied control electrode 4, lines of electric force are formed from the back surface of the aperture 6 to the front surface, and the positively charged toner 22 is directed to the back surface of the aperture 6. The light is pulled out from the surface to the front surface, and is further flown onto the support 10 by the flying electric field formed by the back electrode 11, where it is held and forms an image area.

By applying the same potential as the reference electrode 3 or a positive voltage to the control electrode 4 of the aperture 6 corresponding to the non-image area, the flying electric field caused by the back electrode 11 can be shielded or the electric field inside the aperture 6 can be shielded. By forming electric lines of force from the top surface toward the reference electrode 3 on the back surface, the toner
Suppresses passage through aperture 6. This process is carried out on support 1
By repeating this while conveying 0, a toner image is formed on the entire surface of the support 10. The support 10 on which the toner image is formed passes through a fixing device 13, and the image is fixed on the support 10.

In the above embodiment, the gap between the toner conveying belt 26 and the ultrasonic vibrator 27 is made of air, but as shown in FIG. By coating the back surface of the toner conveying belt 26 upstream of the toner conveying belt 26 and collecting the fluid 103 by the collector 104 downstream of the ultrasonic vibrator 27, the gap between the toner conveying belt 26 and the ultrasonic vibrator 27 is filled with the fluid. The vibration transmission efficiency may be increased.

[0025]

[Effect of the invention] As is clear from the detailed explanation above,
According to the present invention, an inexpensive image forming apparatus can be provided by using a toner supply means that does not require expensive equipment such as a high-voltage AC power supply or a compressor and can easily control passage through an aperture.

Further, since the surface of the toner conveying belt is vibrated by the ultrasonic vibrator through the air, the toner conveying belt is not worn or damaged by the ultrasonic vibrator.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a printing device embodying the present invention.

FIG. 2 is a perspective view showing details of an aperture electrode body.

FIG. 3 is a diagram showing another embodiment.

[Explanation of symbols]

1 Aperture electrode body 2 Insulating layer 3 Reference electrode 4 Control electrode 6 Aperture 8 Control voltage drive circuit 10 Support 11　Back electrode 12 High voltage power supply 20 Drive roller 22 Toner 24 Backup roller 26 Toner conveyance belt 27 Ultrasonic transducer

Claims (1)

[Claims] [Claim 1] Controlling the passage of charged toner through the aperture by applying an image signal to an electrode with an aperture, and printing an image on a support provided on the opposite side of the toner supply source and the electrode with an aperture. The image forming apparatus includes: a toner transport belt disposed to face an aperture; and means for ultrasonically vibrating a surface of the toner transport belt that faces the aperture; An image forming apparatus characterized in that a gap is formed between the image forming apparatus and the means.