JPH08310036A - Image forming device - Google Patents

Abstract

PURPOSE: To realize an image forming device superior in a running cost capable of stably printing. CONSTITUTION: A cleaning brush 23 is provided to a rear face electrode roller 22. The rear face electrode roller 22 is rotated in the non-printing condition and the cleaning brush 23 is reciprocated at a portion of an aperture 6 so that a toner stuck to the aperture 6 is collected. Then, the rear face electrode roller 22 is rotated to covey the cleaning brush to a collection box 27 and the toner held by the cleaning brush 23 is collected into the collection box 27. The toner collected in the collection box 27 is conveyed to a toner case 11 of a record unit by being passed through a toner collection path 25 by virtue of rotation of a screw in the collection box 27. The toner returned to the record unit is used again in the printing by an aperture electrode body 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, toner particles pass through an aperture by applying a drive signal based on an image signal to an aperture electrode body having a plurality of small holes (hereinafter referred to as apertures). An image forming apparatus which obtains an image on an image recording medium such as a printing paper by controlling and passing the toner particles is disclosed in JP-A-6-155798.

In such an image forming apparatus, as shown in FIG. 5, the toner carrying roller 114 and the paper 120 are opposed to each other with the aperture electrode body 101 interposed therebetween, and the paper 12 is also used.
0 is provided with a back electrode roller 122 on the back surface. Further, in the image forming apparatus 100, as shown in FIG. 3, the aperture electrode body 101 includes a plurality of apertures 106 having a diameter of 100 μm on the insulating sheet 102 made of polyimide having a thickness of 25 μ, arranged in a line in the longitudinal direction of the aperture electrode body 101. And a thickness of 1 μm around the aperture 106,
Control electrodes 104 made of a copper foil having a width of 20 μm are formed. As shown in FIG. 5, the aperture electrode body 101 has a surface on which the control electrode 104 is provided on the paper 120.
Are located opposite to. In this image forming apparatus 100, the control voltage application circuit 108 applies a control voltage according to an image signal to the control electrode 104, and a DC power supply 124 applies a flying voltage to the back electrode roller 114 so that the toner carrying roller 114 carries the toner. By controlling the flying of the toner 116, the image is formed on the paper 120.

Further, in the conventional device, the aperture 1
A device disclosed in Japanese Patent Laid-Open No. 4-269563 is known to prevent the toner from accumulating around 06 and clogging of the aperture 106. This device cleans the aperture electrode body by vibrating the aperture and generating a cleaning electric field with the toner carrying roller.

However, in this apparatus, when the vibration and the cleaning electric field are generated, the toner deposited on the surface and the side surface of the aperture facing the toner carrying roller can be cleaned, but the toner deposited on the surface of the aperture facing the paper is surely cleaned. I couldn't do that. Further, there is a drawback that toner is scattered to stain other members because vibration is applied to the aperture.

Therefore, as shown in the specification and drawings of Japanese Patent Application No. 6-251787 by the applicant of the present application, the applicant can move the aperture electrode body into the toner collecting box and rotate it in the collecting box. We have developed a device that physically cleans the toner that has accumulated around the aperture by a brush-shaped collection roller provided in the.

[0007]

However, in the conventional image forming apparatus as described above, the toner cleaned from the aperture electrode body is collected in the collection box, but is discarded as it is. Therefore, there is a drawback that the toner consumption amount as a whole increases and the running cost of the entire apparatus increases.

Further, since a driving mechanism for moving the aperture electrode body is required, there is a drawback that the size of the entire apparatus becomes large.

The present invention has been made to solve the above-mentioned problems, and a first object thereof is to provide an image forming apparatus capable of achieving a low running cost. A second object is to provide an image forming apparatus capable of cleaning the electrode array with a simple structure and downsizing the apparatus.

[0010]

To achieve this object, in an image forming apparatus according to claim 1 of the present invention, a plurality of charged particle passing portions for passing charged particles are formed and each charged particle is charged. An electrode array having a plurality of control electrodes corresponding to the particle passage portion and a charged particle supply means for supplying charged particles to the charged particle passage portion of the electrode array are provided, and the passage of the charged particles to the charged particle passage portion is controlled. In the image forming apparatus for forming an image on the image recording medium by doing so, a collecting means for collecting the charged particles accumulated in the charged particle passage part of the electrode array, and the charged particles supplied by the collecting means. And a conveying means for conveying to the means.

An image forming apparatus according to a second aspect of the invention is provided with a collecting unit that moves relative to the charged particle passage portion of the electrode array and collects the charged particles accumulated in the charged particle passage portion.

The image forming apparatus according to claim 3 is
The charged particles are arranged so as to sandwich the charged particle supply means and the electrode array, and the charged particles that have passed through the charged particle passage portion are caused to fly. And a collecting means provided on the back electrode.

Further, in the image forming apparatus according to a fourth aspect of the present invention, a plurality of charged particle passage portions for passing charged particles are formed, and an electrode array having a plurality of control electrodes corresponding to the respective charged particle passage portions is provided. A charged particle supply means for supplying charged particles to the charged particle passage portion of the electrode array, and a charged particle supply means arranged to sandwich the charged particle supply means and the electrode array and flying the charged particles passing through the charged particle passage portion. An image forming apparatus that includes a back electrode and forms an image on an image recording medium by controlling the passage of charged particles to the charged particle passage portion, is provided on the back electrode, and is deposited on the charged particle passage portion of the electrode array. Collecting means for collecting charged particles, and always separating the collecting means from the electrode array,
And a driving means for driving the back electrode so that the collecting means is engaged with the electrode array when cleaning the electrode array.

Further, in the image forming apparatus according to the fifth aspect, when the collecting means is engaged with the electrode array, the collecting means applies an adhesion voltage so that the charged particles adhere, and the collecting means causes the charged particles to adhere. The power source means applies an emission voltage so that the collecting means releases the charged particles when the collecting means collects the charged particles, and the collecting means collects the charged particles collected by the collecting means.

[0015]

In the image forming apparatus according to claim 1 of the present invention having the above-mentioned structure, when the charged particle supplying means supplies the charged particles to the charged particle passing portion of the electrode array, the electrode array moves from the charged particle passing portion. An image is formed on the image recording medium by passing the charged particles, the collecting means collects the charged particles deposited in the charged particle passage portion of the electrode array, and the conveying means transfers the collected charged particles to the charged particle supply means. Transport.

Further, in the image forming apparatus according to the second aspect, the collecting means moves relative to the charged particle passage portion of the electrode array and collects the charged particles accumulated in the charged particle passage portion.

According to another aspect of the image forming apparatus of the present invention, the back electrode is arranged so as to sandwich the charged particle supply means and the electrode array, and the charged particles passing through the charged particle passing portion are caused to fly so that the collecting operation is always performed. The means is disengaged from the electrode array and is driven to engage the electrode array during cleaning of the electrode array, the collecting means being provided on the back electrode.

Further, in the image forming apparatus according to the present invention, when the charged particle supplying means supplies the charged particles to the charged particle passing portion of the electrode array, the electrode array controls the passage of the charged particles to the charged particle passing portion. Then, the back electrode flies the charged particles that have passed through the charged particle passing portion, the collecting means provided on the back electrode collects the charged particles accumulated in the charged particle passing portion of the electrode array, and the driving means always collects the charged particles. Is removed from the electrode array and the back electrode is driven so that the collector is engaged with the electrode array during cleaning of the electrode array.

Further, in the image forming apparatus according to the present invention, the power supply means applies an adhesion voltage so that the collecting means adheres the charged particles when the collecting means is engaged with the electrode array. When the collecting means collects the charged particles by the collecting means, the collecting means applies an emission voltage so as to discharge the charged particles, and the collecting means collects the charged particles collected by the collecting means.

[0020]

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

First, the image forming apparatus 50 will be described with reference to FIG.

An image forming apparatus 50 which is an embodiment of the present invention.
A toner supply device 10 as a charged particle supply means is provided below the toner supply device 10, and an aperture electrode body 1 as an electrode array for controlling the toner flow is provided above the toner supply device 10. A back electrode roller 22 as a back electrode is arranged above the aperture electrode body 1 with a distance of 1 mm from the aperture electrode body 1.
In the gap between the aperture electrode 1 and the back electrode roller 22,
A sheet 20 as an image recording medium on which an image is formed by toner is inserted and conveyed in the arrow direction. A fixing device 26 that fixes an image on the paper 20 is provided in the conveying direction of the paper 20.

Next, details of each part of the image forming apparatus 50 will be described with reference to the drawings.

As shown in FIG. 1, the toner supply device 10 is provided with a toner case 11 which also serves as a housing of the entire toner supply device 10. In the toner case 11, toner 16 as charged particles is stored. Further, a cylindrical toner carrying roller 14 carrying the toner 16 and carrying it to the aperture electrode body 1 is supported in the toner case 11 so as to be rotatable in the arrow direction. In FIG. 2, a cylindrical supply roller 12 for supplying the toner 16 stored in the toner case 11 to the toner carrying roller 14 is provided at a diagonally lower left portion of the toner carrying roller 14, and the supply roller 12 and the toner are provided. The carrying roller 14 is arranged in parallel with each other and is in contact with the generatrix of its cylindrical surface.

In the toner case 11, above the supply roller 12, the amount of the toner 16 carried by the toner carrying roller 14 is adjusted so as to be uniform on the roller surface of the toner carrying roller 14. A toner layer regulating blade 18 for uniformly charging the toner 16 is provided, and one end of the toner layer regulating blade 18 is pressed against the toner carrying roller 14.

Next, the aperture electrode body 1 will be described with reference to the drawings.

As shown in FIG. 3, the aperture electrode body 1 is composed of an insulating sheet 2 made of polyimide having a thickness of 25 μm. The insulating sheet 2 serves as a circular charged particle passage portion having a diameter of 60 μm. A plurality of apertures 6 are formed in a line in the longitudinal direction of the aperture electrode body 1. Also,
Around the aperture 6, a control electrode 4 made of copper foil having a thickness of 8 μm is formed for each aperture 6.

Here, the aperture 6 is not necessarily limited to the circular shape as shown in FIG.
It may have a shape such as a parallelogram.

The back electrode roller 22 as a back electrode, which is installed so as to face the aperture electrode body 2, will be described. The back electrode roller 22 is a substantially cylindrical metal rod, and a cleaning brush 23 as a collecting means extending in the longitudinal direction of the metal rod is provided in a part of the back electrode roller 22.

Further, a motor 30 as a driving means is connected to the back electrode roller 22, so that the back electrode roller 22 is rotationally driven in the arrow direction.
Due to the rotation of the back electrode roller 22, the cleaning brush 23 is normally arranged on the opposite side of the sheet conveying path as shown in FIG. 2, and when the printing is completed,
The aperture electrode 1 is rotated to collect excess toner adhering to the vicinity of the aperture 6 and clean the aperture electrode body 1. A collection box 27 as a collection unit is provided on the side of the back electrode roller 22, and is configured to collect the excess toner collected by the cleaning brush 23.

Next, the toner recovery path 25 as the conveying means of the present invention will be described with reference to FIG.

FIG. 1 is a perspective view of the main part of the image forming apparatus of this embodiment. A substantially U-shaped toner recovery path 25 is provided so as to avoid the transportation path of the sheet 20 formed between the carrying roller 14 and the back electrode 22. The toner collection path 25 includes a collection box 27 and the recording unit 10.
And the toner case 11 of FIG.
There is no problem on either the right side or left side of the
If the paper transportation route is not obstructed, it may be arranged in the center of the apparatus so as to make a large round trip of the transportation route.

A screw 32 is built in the recovery box 27 and the toner recovery path 25, and the recovery box 27 is rotated by a motor 34.
The toner 16 collected in 1 is conveyed to the toner case 11. A coil spring may be used instead of the screw 32.

Further, the toner collecting path 25 may be provided with a waste toner classifying mechanism such as a mesh filter or a paper dust removing mechanism (not shown). In this case, the more suitable toner can be sent to the toner case 11.

Next, the control device for each electrode will be described. As shown in FIG. 2, a control voltage application circuit 8 is connected between the control electrode 4 and the toner carrying roller 14. The control voltage applying circuit 8 is -30 V with respect to the control electrode 4 based on the image signal sent from the CPU 36.
Alternatively, it is configured to apply a voltage of + 30V. The carrying roller 14 is grounded. Incidentally, CPU3
Reference numeral 6 is connected to an external computer, an image reading device, an image communication device, or the like, and is configured to operate according to a flowchart described later.

Further, a backside voltage applying circuit 24 as a power supply means is connected between the backside electrode roller 22 and the toner carrying roller 14, and the backside voltage applying circuit 2 is provided.
4 is configured to be able to apply a voltage of +1 kV or -1 kV to the back electrode roller 22 and the cleaning brush 23 in accordance with a command from the CPU 36.

Next, the operation of the image forming apparatus configured as described above will be described with reference to the flowchart of FIG.

First, when a print request is issued from an external device, the CPU 36 determines in step S1 (hereinafter referred to as S1 and other steps are the same) that the print operation is started, and in step S2, the print operation is started. I do.

This printing operation will be described. When the supply roller 12 rotates in the direction of the arrow, the toner case 11 is rotated.
The toner 16 stored inside is the toner carrying roller 14
Be transported to. Then, the toner 1 that has been conveyed
6 is rubbed against the toner carrying roller 14 and is negatively charged and carried on the toner carrying roller 14. The toner 16 carried on the toner carrying roller 14 is conveyed while being carried on the cylindrical roller surface of the toner carrying roller 16 as the toner carrying roller 14 rotates in the direction of the arrow, and is conveyed by the toner layer regulating blade 18 to a thin layer. After being made uniform and the charging is made uniform, the toner carrying roller 14 is conveyed toward the aperture electrode body 1 by rotating in the direction of arrow B. Then, the toner on the toner carrying roller 14 is supplied under the aperture 6 while being rubbed by the insulating sheet 2 of the aperture electrode body 1.

Then, according to the image signal sent from the CPU 36, the control voltage applying circuit 8 applies a voltage of +30 V to the control electrode 4 corresponding to the image portion. As a result, an electric force line from the control electrode 4 toward the toner carrying roller 14 is formed in the aperture 6 in the control electrode 4 to which the voltage is applied due to the potential difference between the control electrode 4 and the reference electrode 3. 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 is transferred to the backside voltage application circuit 24.
Is applied to the rear electrode roller 22 by an electric field formed between the paper 20 and the aperture electrode body 1 by the voltage of +1 kV, and the light beam flies toward the paper 20 and is deposited on the paper 20 to form pixels. . At this point, the back electrode roller 22 is stopped at the position shown in FIG.

A voltage of -30 V is applied from the control voltage applying circuit 8 to the control electrode 4 corresponding to the non-image part. As a result, an electric field is not formed between the reference electrode 3, the toner carrying roller 14, and the control electrode 4, so that the toner 16 on the toner carrying roller 14 does not receive an electrostatic force and thus does not pass through the aperture 6. Therefore, no pixel is formed on the portion of the paper 20 facing the control electrode 4.

Here, the paper 20 has toner 1 on its surface.
When one row of pixels is formed by 6, then, by one carrying means (not shown), one pixel is carried in the direction perpendicular to the six rows of apertures. Then, the toner image is formed on the entire surface of the paper 20 by repeating the above-described image forming process. Then, the formed toner image is conveyed to the fixing device 26 by a not-shown conveying device, and is fixed on the paper 20 by the fixing device 26. The fixing device 26 may be either a heat fixing type or a pressure fixing type.

By repeating the above process,
Although an image is recorded on the paper 20, most of the paper is a non-printing portion, or in the space between the conveyed papers, the non-control toner happens to pass through the aperture and the back surface of the aperture electrode body 1. It may fly and accumulate on the electrode facing surface.

Then, the operation for cleaning the periphery of the aperture 6 of the aperture electrode body 1 will be described.

When the CPU 36 determines in S3 that the printing is completed and is in the non-printing state, the CPU 36 drives the motor 30 to rotate the back electrode roller 22 in the arrow direction in S4, and in S5, the cleaning brush 23. When it is determined that has reached the position of the aperture 6, the operation of cleaning the periphery of the aperture 6 of the aperture electrode body 1 is performed in S6.

That is, the CPU 36 controls the back voltage application circuit 24 and the motor 30 to control the back electrode roller 22.
The toner 16 is attracted to the cleaning brush 23 by applying a voltage of +1 kV via the cleaning brush 23, and the back electrode roller 22 is repeatedly rotated normally and reversely to move the cleaning brush 23 back and forth at the aperture 6. Therefore, the toner 16 attached to the aperture 6 can be collected.

When it is determined in S7 that the above operation has been performed for the predetermined time, the CPU 36 rotates the back electrode roller 22 again in the arrow direction in S8.
Even during this rotation, the voltage of +1 kV is applied to the cleaning brush 23, so that the collected toner 16 is reliably held by the cleaning brush 23 and carried. Therefore, the toner 16 collected by the cleaning brush 23 does not scatter and stain other members.

When the cleaning brush 23 moves to the collection box 27 by the rotation of the back electrode roller 22, the CPU 36 at S9, the cleaning brush 2
3 is determined to have moved to the collection box 27, S1
At 0, a voltage of -1 kV is applied to the back electrode roller 22 while rotating the back electrode roller 22. Therefore, the toner 16 collected and held by the cleaning brush 23 is positively separated from the cleaning brush 23, scraped off by the side wall of the collection box 27, and collected in the collection box 27. Therefore, this + 1kV and -1kV
Voltage corresponds to the adhesion voltage and the emission voltage of the present invention.
The emission voltage does not have to be -1 kV and may be 0 V, for example.
The voltage of may be.

The toner 16 collected in the collecting box 27 is carried to the toner case 11 of the recording unit 10 through the toner collecting path 25 by the rotation of the screw 32 in the collecting box 27. The toner 16 returned to the recording unit 10 can be printed again by the aperture electrode body 1. Therefore, the cleaned toner can be reused without being discarded as excess toner, and thus the running cost can be significantly reduced.

Further, since the rear electrode roller 22 is provided with the cleaning brush 23 and the rear electrode roller 22 is rotated to clean the periphery of the aperture 6 of the aperture electrode body 1, the structure of the cleaning device is simplified. The size of the entire device can be greatly reduced.

In the present embodiment, the non-printing for cleaning means not only the time when printing is not performed on one sheet of paper by the image data, but also the gap between the continuously conveyed sheets is the aperture electrode. Cleaning brush 2 including time to pass under, time to start machine and start printing, time to finish printing and stop machine, etc.
3 indicates all the time when there is no problem even if it exists near the aperture 6.

Further, in the image forming apparatus 50 of this embodiment,
Since the insulating sheet 2 of the aperture electrode body 1 is directed to the toner carrying roller 14 side, even if the toner 16 is not present on the toner carrying roller 14 due to a malfunction of the toner supply system, the control electrode 4 and the toner carrying roller 14 are not present. Does not damage the control voltage application circuit 8 due to contact with each other and electrical short circuit.

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

For example, in the above embodiment, the cleaning brush 23 is used as the collecting means, but the sponge or cloth may be used instead of the brush.

Further, in the above embodiment, the cleaning brush 23 is provided on the back electrode roller 22 and the aperture electrode body 1 is cleaned by rotating the back electrode roller 22. -25
The cleaning device described in the specification of 1787 and the drawings may be adopted. That is, in this apparatus, the recovery box and the toner case may be connected through the toner recovery path to return the recovered toner to the toner case.

Further, in the above embodiment, the control voltage of the aperture corresponding to the non-image portion is set to -30V, but it may be zero voltage. In this case, lower voltage driving is possible.

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 the specification of US Pat. No. 5,036,341. Is.

[0058]

As is apparent from the above description,
In the image forming apparatus of the present invention, the collecting means collects the charged particles deposited in the charged particle passage portion of the electrode array, and the conveying means conveys the collected charged particles to the charged particle supplying means, Since it is used again, low running cost can be achieved.

Further, according to the image forming apparatus of the present invention, the back electrode is provided with the collecting means, and the back electrode is driven so that the collecting means collects the charged particles deposited in the charged particle passage portion of the electrode array. The electrode array can be cleaned with a simple structure, and the device can be downsized.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a configuration of a main part of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a front view showing the configuration of the image forming apparatus.

FIG. 3 is a perspective view showing a configuration of an aperture electrode body used in the image forming apparatus and a conventional image forming apparatus.

FIG. 4 is a flowchart for explaining the operation of the image forming apparatus.

FIG. 5 is a front view showing a configuration of a conventional image forming apparatus.

[Explanation of symbols]

 1 Aperture Electrode 2 Insulating Sheet 4 Control Electrode 6 Aperture 11 Toner Case 14 Toner Carrying Roller 16 Toner 20 Paper 22 Back Electrode Roller 23 Cleaning Brush 24 Back Voltage Application Circuit 25 Toner Collection Path 27 Collection Box 30 Motor 32 Screw 36 CPU

Claims (5)

[Claims] 1. An electrode array having a plurality of charged particle passages through which charged particles pass and a plurality of control electrodes corresponding to the respective charged particle passages, and a charged particle passage portion of the electrode array. An image forming apparatus, comprising: a charged particle supply unit for supplying charged particles, wherein an image is formed on an image recording medium by controlling the passage of the charged particles to the charged particle passage unit. An image forming apparatus comprising: a collecting unit for collecting the accumulated charged particles, and a conveying unit for conveying the charged particles collected by the collecting unit to the charged particle supplying unit. 2. The collecting means moves relative to a charged particle passage portion of the electrode array and collects the charged particles accumulated in the charged particle passage portion. Image forming apparatus. 3. A back electrode arranged to sandwich the charged particle supply means and the electrode array and flying the charged particles passing through the charged particle passage, the collecting means being provided on the back electrode. 3. The back electrode is driven so as to always disengage the collecting means from the electrode array and engage the collecting means with the electrode array when cleaning the electrode array. Image forming apparatus. 4. An electrode array having a plurality of charged particle passages through which charged particles pass and a plurality of control electrodes corresponding to the respective charged particle passages, and a charged particle passage portion of the electrode array. Charged particles are provided with a charged particle supply means for supplying charged particles, and a back electrode for sandwiching the charged particle supply means and the electrode array and for flying the charged particles passing through the charged particle passage. In an image forming apparatus for forming an image on an image recording medium by controlling passage to a particle passage portion, a collection for collecting charged particles provided in the back electrode and accumulated in a charged particle passage portion of the electrode array. Means for disengaging the collecting means from the electrode array at all times and driving the back electrode to engage the collecting means with the electrode array during cleaning of the electrode array. An image forming apparatus characterized by comprising a dynamic means. 5. A power source means for applying a voltage to the collecting means via the back electrode, and a collecting means for collecting the charged particles collected by the collecting means, wherein the power source means has the collecting means. When engaged with the electrode array, the collecting means applies an attachment voltage so as to adhere the charged particles, and when the collecting means causes the collecting means to collect the charged particles, the collecting means emits the charged particles. The image forming apparatus according to claim 4, wherein an emission voltage is applied.