JPH08267815A - Image forming apparatus - Google Patents

Abstract

PURPOSE: To provide an image forming apparatus simple in constitution and capable of cleaning an aperture electrode element to facilitate stable recording. CONSTITUTION: A CPU 48 drives a motor 34 to allow a chasis 23 and a back electrode roller 22 to retreat from the vicinity of an aperture electrode element 1 and also drives a motor 32 to revolve an opening member 30 and the aperture electrode element 1 to open apertures 6 to the outside. The CPU 48 further drives a motor 46 to revolve a cam member 42 to revolve a cleaning member 36 toward the aperture electrode element 1 and also drives a motor 44 to allow the cleaning member 36 to slide to the aperture electrode element 1. The reciprocal movement of the cleaning member 36 is repeated in such a state that a sponge piece 40 is in contact with the apertures 6 to peel the toner 16 bonded to the vicinity of the apertures 6 of the aperture electrode element 1 on the side of a toner carrying roller 14 to perform the cleaning of the aperture electrode 1.

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 which can be used in copying machines, printers, plotters, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, as one of image forming apparatuses, an electrode having a plurality of openings (hereinafter referred to as apertures) is used, and a voltage is applied to the electrode based on image data. U.S. Pat. No. 3,689,935 discloses controlling toner particles so that they can pass through the aperture and forming an image on a sheet by the toner particles that have passed.

This image forming apparatus comprises a flat plate made of an insulating material, a continuous reference electrode formed on one surface of the flat plate, and a plurality of control electrodes insulated from each other formed on the other surface. , An aperture electrode body having at least one row of apertures formed through each of the control electrodes, and a means for selectively applying a potential between the reference electrode and the control electrode. From means for supplying charged toner particles so that the electric potential modulates the flow of toner particles passing through the aperture, and means for positioning the paper in the particle flow path so that the paper and the aperture electrode body can move relative to each other. It is configured.

Also, for example, US Pat. No. 4,743,926.
Nos. 4,755,837, 4,780,733, and 4,847,796 disclose an image forming apparatus in which an aperture electrode body is arranged with a control electrode on the paper side and a reference electrode on the toner supply side. There is.

In contrast, US Pat. No. 4,912,489
In the specification of No. 3, the aperture electrode body is a reference electrode on the paper side,
By arranging the control electrode facing the toner supply side,
It is described that the voltage applied to the control electrode when it is off can be suppressed to about 1/4 of that of the image forming apparatus disclosed in the above-mentioned US patent.

Here, the off state means a time when the toner particles are not adhered to the paper, that is, a time when a blank portion of the image is formed, and conversely, the on time means that the toner is on the paper. It means the time when an image is formed.

[0007]

However, the conventional image forming apparatus as described above has the following problems. That is, a coating layer is provided on the toner supply side surface of the aperture electrode body in order to optimize the sliding state with the toner electrically and mechanically. Conventionally, this coat layer has been prepared by adding a conductive material such as carbon and a slidability-imparting material such as silica using polyimide, which is the same material as the insulating sheet of the aperture electrode body, as a binder. However, even if the additive is added as such a countermeasure, the toner adheres to the coat layer during printing, and it is difficult for the adhered toner to be controlled by the electric field, resulting in deterioration of image quality. Was.

Periodically removing the toner adhering to the aperture electrode body has been a necessary condition for stabilizing printing. To address such a problem, the applicant of the present application proposes in Japanese Patent Application No. 6-251787 that the aperture electrode body is moved from the carrying roller portion and cleaning is performed at the position where the aperture is moved.

When cleaning is performed by such a method, the aperture electrode body has to be largely moved. For this reason, a large-scale mechanism is required, and the apparatus becomes large in size or moves, whereby the positions of the aperture electrode body and the carrying roller are displaced, and good printing cannot be performed.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide an image forming apparatus capable of stable recording.

[0011]

In order to achieve this object, an image forming apparatus according to a first aspect of the present invention comprises a carrier for supporting and supplying charged particles, and the carrier is disposed in the vicinity of the carrier.
In an image forming apparatus having an electric field control means for controlling an electric field around a plurality of openings through which charged particles of a carrier pass, an opening means for opening at least the openings of the electric field control means from the carrier. And cleaning means for cleaning the opening portion of the electric field control means opened by the opening means from the side facing the carrier.

An image forming apparatus according to a second aspect of the invention is provided with an electric field control means for opening the opening portion from the carrier by being rotated about one end as a fulcrum.

The image forming apparatus according to claim 3 is
It has a charged particle removing member at its tip and is provided with cleaning means for cleaning the opening by moving the charged particle removing member to the opened opening.

Further, in the image forming apparatus according to a fourth aspect of the present invention, a counter electrode disposed between the electric field control means and the image receiving body to apply a predetermined potential to the image receiving body, and a retracting means for retracting the counter electrode from the electric field controlling means. And are further equipped.

An image forming apparatus according to a fifth aspect of the invention is provided with an opening means for opening the electric field control means after the counter electrode is retracted by the retracting means.

[0016]

In the image forming apparatus having the above-mentioned structure according to the present invention, the opening means opens at least the opening of the electric field control means from the carrier, and the cleaning means opens the electric field by the opening means. The opening of the control means is cleaned from the side facing the carrier.

Further, in the image forming apparatus according to the second aspect, the opening portion is opened from the carrier by rotating the electric field control means with one end as a fulcrum.

In the image forming apparatus according to the third aspect, the cleaning means has a charged particle removing member at its tip, and the charged particle removing member moves to the opened opening portion to clean the opening portion. To do.

Further, in the image forming apparatus according to the present invention, the counter electrode is arranged so as to sandwich the electric field control means and the image receptor, and gives a predetermined potential to the image receptor, and the retracting means moves the counter electrode from the electric field control means. Evacuate.

Further, in the image forming apparatus according to the fifth aspect, the opening means opens the electric field control means after the retraction means retracts the counter electrode.

[0021]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an outline of an image forming apparatus of the present invention, in which a columnar column serving as a counter electrode has a gap of 1 mm below an aperture electrode body 1 serving as an electric field control means. The rear electrode roller 22 is rotatably arranged on the chassis 23, and is configured to be able to convey the sheet 20 as an image receiving body inserted in the gap. In addition, the aperture electrode body 1 is provided above the aperture electrode body 1.
A toner supply device 10 is provided along the longitudinal direction of the sheet, and a fixing device 26 is provided at the destination of the sheet 20 conveyed by the back electrode roller 22.

Next, the respective components will be described in detail. The toner supply device 10 includes a toner case 11 which also serves as a housing of the entire device, and a toner 16 as charged particles contained in the toner case 11. A supply roller 12, a toner carrying roller 14 as a carrying member, and a toner layer regulating blade 18 are provided. Here, the toner carrying roller 14 carries the toner 16 and conveys it toward the aperture electrode body 1.
The supply roller 12 supplies the toner 16 to the toner carrying roller 14.

The supply roller 12 and the toner carrying roller 14 are rotatably supported by the toner case 11 in the direction of the arrow shown in FIG. Further, the toner layer regulating blade 18
Is for adjusting the amount of the toner 16 carried on the toner carrying roller 14 to be uniform on the roller surface and for uniformly charging the toner 16, and is pressed against the toner carrying roller 14. .

As shown in FIG. 2, the aperture electrode body 1 has a 25 μm thick insulating sheet 2 made of polyimide and a diameter of 1 μm.
Apertures 6 having a plurality of openings each having a size of 00 μm are formed in one row, and a control electrode 4 having a thickness of 1 μm is formed on each upper surface of each aperture 6. As shown in FIG. 1, the aperture electrode body 1 is pressed against the toner carrying roller 14 at the aperture position of the insulating sheet 2 with the control electrode 4 facing the sheet 20 side.

A control voltage applying circuit 8 is connected between the control electrode 4 and the toner carrying roller 14.
The control voltage application circuit 8 is configured to apply a voltage of 0 V or +50 V to the control electrode 4 based on the image signal.

Further, a DC power source 24 is connected between the back electrode roller 22 and the toner carrying roller 14, and this DC power source is + with respect to the back electrode roller 22.
A voltage of 1 kV can be applied.

Next, a mechanism for cleaning the aperture electrode body 1 will be described.

The aperture electrode body 1 is a toner carrying roller 1
An opening member 30 is attached to the surface on the 4 side, and is configured to be rotatable at one end thereof according to the rotation of the opening member 30,
When the aperture electrode body 1 is rotated, the aperture 6 is opened outward. The opening member 30 is connected to the motor 32 and is driven according to the rotation of the motor 32. Therefore, the opening member 30 and the motor 32 form an opening means.

A motor 34 is connected to the chassis 23, and is driven in the direction of the arrow by driving the motor 34,
The back electrode roller 22 is configured to be retracted from the aperture electrode body 1. Therefore, the chassis 23 and the motor 3
4 and 4 constitute the evacuation means.

The cleaning member 36 is rotatably and slidably provided on a fixed shaft 38, and a sponge piece 40 as a charged particle removing member is attached to the tip thereof. The sponge piece 40 is formed laterally long so as to be able to contact all of the plurality of apertures 6, and peels off the toner 16 adhering to the surface of the aperture electrode body 1 on the toner carrying roller 14 side, in particular, in the vicinity of the aperture 6 to remove the aperture electrode. It is configured to clean the body 1. A brush, rubber, or the like may be used instead of the sponge piece 40.

Further, the cam member 42 is provided so as to contact the cleaning member 36, and the cleaning member 36 is rotated by its rotation. A motor 44 is connected to slide the cleaning member 36, and a motor 46 is connected to rotate the cam member 42 to rotate the cleaning member 36. Therefore, the cleaning member 3
6 and the cam member 42 and the motors 44 and 46 constitute a cleaning means. Further, each motor 32, 34, 44, 46
A CPU 48 for controlling the rotation is connected to the.

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

First, by rotating the toner carrying roller 14 and the supplying roller 12 in the direction of the arrow shown in FIG. 1, the toner 16 sent from the supplying roller 12 is rubbed against the toner carrying roller 14 to be negatively charged. The toner is carried on the toner carrying roller 14. Toner 1 carried
The layer 6 is thinned by the layer regulating blade 18 and charged, and then is conveyed toward the aperture electrode body 1 by the rotation of the toner carrying roller 14. Then, the toner on the toner carrying roller 14 is supplied onto the aperture 6 while being rubbed by the insulating sheet 2 of the aperture electrode body 1.

Here, in accordance with the image signal, the control voltage applying circuit 8 adds + to the control electrode 4 corresponding to the image portion.
A voltage of 50V is applied. As a result, electric lines of force from the control electrode 4 toward the toner carrying roller 14 are formed in the vicinity of the aperture 6 corresponding to the image portion due to the potential difference between the control electrode 4 and the toner carrying roller 14. As a result, the negatively charged toner receives an electrostatic force in the direction of higher electric potential, passes through the aperture 6 from the toner carrying roller 14, and is drawn out to the control electrode 4 side. The extracted toner 16 further flies toward the paper 20 due to the electric field formed between the paper 20 and the aperture electrode body 1 by the voltage applied to the back electrode roller 22, and is deposited on the paper 20. To form pixels.

A voltage of 0V is applied from the control voltage applying circuit 8 to the control electrode 4 corresponding to the non-image portion.
As a result, since no electric field is formed between the toner carrying roller 14 and the control electrode 4, the toner carrying roller 1
The toner 16 on 4 does not pass through the aperture 6 because it is not subjected to electrostatic force.

Further, the paper 20 has toner 1 on its surface.
While one column of pixels is formed by 6, one pixel is sent in the direction perpendicular to the aperture column. Then, by repeating the above process, a toner image is formed on the entire surface of the paper 20. After that, the formed toner image is transferred to the fixing device 26.
It is fixed on the sheet 20 by.

Next, the cleaning operation of the aperture electrode body 1 will be described. When the above-mentioned image formation is repeated, the toner 16 adheres to the vicinity of the aperture 6 on the toner carrying roller 14 side of the aperture electrode body 1 and the aperture 6 is clogged. Therefore, when the total time of image formation exceeds a predetermined time or the operator gives a cleaning instruction,
Start cleaning work.

First, the CPU 48 drives the motor 34 to retract the chassis 23 and the back electrode roller 22 from the vicinity of the aperture electrode body 1. Then, the CPU 48 drives the motor 32 to rotate the opening member 30 and the aperture electrode body 1 to open the aperture 6 to the outside. Next, CPU4
8 drives the motor 46 to rotate the cam member 42, and the rotation of the cam member 42 causes the cleaning member 36 to rotate toward the aperture electrode body 1. And CPU
48 drives the motor 44 to slide the cleaning member 36 toward the aperture electrode body 1. Then, the sponge piece 40 repeats the reciprocating movement in a state of being in contact with the aperture 6, so that the toner 16 adhering to the vicinity of the aperture 6 of the aperture electrode body 1 on the toner carrying roller 14 side is peeled off and cleaned. Then, after the cleaning is completed, the CPU 48
Drives each motor to return it to its original state.

As described above in detail, according to this embodiment, the surface of the aperture electrode body 1 on the toner carrying roller 14 side can be cleaned with a simple structure.

[0041]

As described above in detail, in the image forming apparatus of the present invention, the surface of the aperture electrode facing the carrier can be cleaned by a simple mechanism without unnecessarily increasing the size of the apparatus. Therefore, it is possible to avoid deterioration of image quality caused by the toner adhering to the aperture electrode during printing, and it is possible to perform good recording.

[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 details of an aperture electrode body mounted on the image forming apparatus shown in FIG.

FIG. 3 is a diagram showing a cleaning state of the image forming apparatus of the present invention.

[Explanation of symbols]

 1 Aperture Electrode Body 4 Control Electrode 6 Aperture 14 Toner Bearing Roller 22 Back Electrode Roller 23 Chassis 30 Opening Member 32 Motor 34 Motor 36 Cleaning Member 40 Sponge Piece 42 Cam Member 44 Motor 46 Motor

Claims (5)

[Claims] 1. A carrier for supporting and supplying charged particles, and an electric field control means arranged in the vicinity of the carrier for controlling an electric field around a plurality of openings of the carrier for passing charged particles. In the image forming apparatus, the opening means for opening at least the opening portion of the electric field control means from the carrier, and the opening portion of the electric field control means opened by the opening means from the side facing the carrier body. An image forming apparatus comprising: a cleaning unit for cleaning. 2. The image forming apparatus according to claim 1, wherein the electric field control unit is rotated about one end thereof as a fulcrum to open the opening portion from the carrier. 3. The cleaning means has a charged particle removing member at its tip, and moves the charged particle removing member to the opened opening portion to clean the opening portion. The image forming apparatus according to claim 1 or 2. 4. An electric field control means and an opposed electrode arranged to sandwich the image receptor to apply a predetermined potential to the image receptor, and an evacuation means to evacuate the opposed electrode from the electric field control means. The image forming apparatus according to any one of claims 1 to 3. 5. The image forming apparatus according to claim 4, wherein the opening unit opens the electric field control unit after the retraction unit retracts the counter electrode.