JPH10315527A - Image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming system in which temperature rise due to heating of a control circuit means is avoided utilizing a control electrode. SOLUTION: The image forming system comprises a supply means having a carrier 22 carrying at least one color of developer 21, a counter electrode 25 disposed oppositely to the carrier 22, a power supply means 30 supplying a high voltage for generating a potential difference between the carrier 22 and the counter electrode 25, an insulating substrate interposed between the carrier 22 and the counter electrode 25, a plurality of gates for passing the developer 21 provided on the insulating substrate, a control electrode 26 comprising at least one group of electrodes arranged around the plurality of gates 29, and a control means comprising a control circuit means for imparting a plurality of potential states to each electrode 26. Passage of the developer 21 through the gate 29 is controlled by applying a specified potential to a corresponding electrode in the electrode group by the control means and an image is formed on the surface of a recording medium 5 carried to the counter electrode 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to digital copiers and facsimile-equipped printing units, digital printers, plotters, etc., and forms an image on a recording medium by flying a developer. It concerns the device.

[0002]

2. Description of the Related Art In recent years, as an image forming apparatus for outputting an image signal as a visible image on a recording medium such as paper, for example, as described in JP-A-7-266608 and JP-A-6-106767, charged particles are used. An electric field is applied to the recording medium to fly it by electric force, and the potential applied to a control electrode including a plurality of through-holes arranged in the flight path is changed to cause charged particles to adhere to the recording medium. 2. Description of the Related Art There has been proposed an image forming apparatus which directly forms an image on the upper surface.

The above prior art describes the material of the control electrode, but has a different structure from that of the present invention and causes the following problems.

[0004]

In an image forming apparatus of the type typified by the above prior art, control means for controlling the passage of charged particles through a gate is used. An image forming apparatus of the type described in the prior art described above controls whether or not toner can fly by controlling an electric field formed between the gate and the carrier, and uses a strong electric field formed by a counter electrode to form a surface of a sheet as a recording medium. To form an image.

Generally, polyimide is used as a base material for the control electrode, and an epoxy resin is used as a protective layer on the outermost surface. Since the epoxy layer is usually used by being mixed with other organic materials, its thermal conductivity is remarkably reduced.

On the other hand, in order to save the space of the device, a driver including many FETs as a potential switching means for controlling the potential of the control electrode is usually arranged on the control electrode. Since the driver controls a number of channels simultaneously, it generates considerable heat. The heat using the driver as a heat source is conducted to the inside of the control electrode via a copper foil or the like used as an electrode pattern.

However, as described above, the substrate of the control electrode is made of polyimide having a very low thermal conductivity and the thermal conductivity of the protective layer is also low as described above. Heat is not easily dissipated, and is accumulated inside the control electrode, causing an increase in temperature. When the temperature of the control electrode rises, the control electrode itself expands, causing a change in the position of the control electrode, in particular, the distance between the portion where the gate is formed and the toner carrier.

If the distance between the gate and the toner carrier changes, the potential required for toner flight control also changes, making it difficult to control the desired toner flight and causing poor printing. A circuit for adjusting the potential to be applied to the electrodes arranged in the device is required separately, and an increase in the number of components and an increase in the size and cost of the device cannot be avoided.

Further, as described above, since the control electrode has a multilayer structure, it is common, and the temperature and the thermal expansion coefficient of each layer are different. Therefore, when the above-mentioned temperature rise occurs, the control electrode has a difference in the thermal expansion coefficient of each layer. Distortion is likely to occur, and the gate position changes from a desired position, thus causing the above-described problem.

Further, if the above-mentioned heat generation is repeated and the thermal expansion is repeated, the adhesion portions of the respective layers are broken, causing problems such as a reduction in the life of the control electrode. Furthermore, the temperature of the driver, which is a heat source, becomes high, which causes the driver to malfunction.

In order to avoid this inconvenience, it is common to arrange a heat sink or a fan to cool the driver to be used. However, since the number of the drivers is large, there is a problem in terms of space. In addition to the difficulty in arranging the heatsink, an increase in the number of parts and an increase in the size and cost of the device are inevitable.

[0012]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a supply unit having a carrier for carrying a developer of at least one color; a counter electrode disposed to face the carrier; A high-voltage power supply for supplying a high voltage that generates a potential difference between the carrier and the counter electrode; an insulating substrate disposed between the carrier and the counter electrode; and a microscope provided on the insulating substrate. A control electrode comprising a plurality of gates serving as a passage portion of the image agent and at least one electrode group provided around the plurality of gates, and a control circuit for providing a plurality of potential states of each electrode of the control electrode Means for controlling the passage of the developer through the gate by applying a predetermined potential to the corresponding electrodes of the electrode group by the control means, and transporting the developer to the counter electrode. Image on the recording medium surface An image forming apparatus for forming,
The control circuit means includes switching means for switching a potential state of the control electrode, and at least the switching means is arranged on the control electrode, wherein the switching using at least the switching means or the control circuit means as a heat source An image forming apparatus characterized in that at least one of the means, the control circuit means, and the control electrode is prevented from increasing in temperature by using the control electrode.

According to a second aspect of the present invention, there is provided the image forming apparatus, wherein the control electrode includes the switching means or the control circuit means, or a high thermal conductivity member in contact with the switching means or the control circuit means.

According to a third aspect of the present invention, in the image forming apparatus, the control electrode has a high thermal conductivity member that contacts a power supply member connected to the switching means.

According to a fourth aspect of the present invention, in the image forming apparatus, the high heat conductive member is a protective layer disposed on the outermost surface of the control electrode.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) A cross section of a printer equipped with an image forming apparatus according to the present embodiment is shown in FIG. 1, and an outline of each element will be described with reference to FIG.

In the following description, an image forming apparatus having a configuration corresponding to a negatively charged toner will be described in detail. However, when a positively charged toner is used, the applied voltage is appropriately adjusted accordingly. What is necessary is just to set a polarity. As shown in FIG. 2, an image forming unit 1 having a toner supply unit 2 and a printing unit 3
It has. The image forming section 1 visualizes an image corresponding to an image signal on a sheet as a recording medium using toner as a developer.

That is, the present image forming apparatus directly forms an image on a sheet of paper by controlling the flying of the toner based on an image signal while causing the toner to fly and adhere to the sheet. A paper feeding device 10 is provided on the side of the paper entering the image forming unit 1. Paper feeder 10
Is composed of a paper cassette 4 for storing paper 5 as a recording medium, a pickup roller 6 for feeding out the paper 5 from the paper cassette 4, and a paper feed guide 7 for guiding the supplied paper 5.

The paper feeder 10 has a paper feed sensor (not shown) for detecting that the paper 5 has been supplied. The pickup roller 6 is driven to rotate by a driving device (not shown). A fixing unit 11 that fixes the toner image formed on the sheet 5 in the image forming unit 1 to the sheet 5 by heating and pressing is provided on the sheet output side of the sheet from the image forming unit 1. I have. Fixing unit 11
Comprises a ripening roller 12, a heater 13, a pressure roller 14, a temperature sensor 15, and a temperature control circuit 80.

The heating roller 12 is made of, for example, an aluminum tube having a thickness of 2 mm. The heater 13 is formed of, for example, a halogen lamp, and is built in the heating roller 12. The pressure roller 14 is made of, for example, a silicone resin.

The heating roller 12 and the pressure roller 14, which are provided opposite to each other, have a spring or the like (not shown) at both ends of each shaft, for example, 2 kg so that the paper 5 can be pressed. Is applied. The temperature sensor 15 measures the temperature of the surface of the heating roller 12. The temperature control circuit 80 is controlled by the main control unit, and controls ON / OFF of the heater 13 based on the measurement result of the temperature sensor 15 to maintain the temperature of the surface of the heating roller 12 at, for example, 150 ° C. .

The fixing unit 11 has a paper discharge sensor (not shown) for detecting that the paper 5 has been discharged.
The materials of the heating roller 12, the heater 13, the pressure roller 14, and the like are not particularly limited. Further, the temperature of the surface of the heating roller 12 is not particularly limited.

Further, the fixing unit 11 may be configured to fix the toner image by heating or pressing the paper 5. Although not shown, the fixing unit 11
A paper discharge roller that discharges the paper 5 processed by the fixing unit 11 onto a paper discharge tray, and a paper discharge tray that receives the discharged paper 5 are provided on the paper output side of the paper.

The above-mentioned heating roller 12, pressure roller 14,
The paper discharge roller is driven to rotate by a driving device (not shown). The toner supply unit 2 of the image forming unit 1 includes a toner storage tank 2 in which a toner 21 as a developer is stored.
A toner carrier 22 as a cylindrical carrier (sleeve) for carrying the toner 21 by magnetic force, and a toner storage tank 20 are provided inside the toner carrier 22 to charge the toner 21 and to provide an outer periphery of the toner carrier 22. The doctor blade 23 regulates the thickness of the toner layer carried on the surface.

The doctor blade 23 holds the toner carrier 2
2 is provided on the upstream side in the rotation direction such that the distance from the outer peripheral surface of the toner carrier 22 is, for example, 60 μm. The toner 21 is, for example, a magnetic toner having an average particle diameter of 6 μm, and is charged by the doctor blade 23 so that the charge amount is, for example, −4 μC / g to −5 μC / g. The distance between the doctor blade 23 and the toner carrier 22 is not particularly limited. Further, the average particle size, the charge amount, and the like of the toner 21 are not particularly limited.

The toner carrier 22 is driven by a driving device (not shown), and rotates in a direction indicated by an arrow A in FIG. Further, the toner carrier 22 is grounded, and a position facing the doctor blade 23 inside the toner carrier 22;
A magnet (not shown) is arranged at a position facing the control electrode 26 (described later).

As a result, the toner carrier 22 can carry the toner 21 on its outer peripheral surface. Further, the toner 21 carried on the outer peripheral surface of the toner carrier 22 forms ears at positions corresponding to the above positions on the outer peripheral surface. The rotation speed of the toner carrier 22 is not particularly limited.

Further, instead of carrying the toner 21 by a magnetic force, the toner carrier 22 may be configured to carry the toner 21 by an electric force or an electric force and a magnetic force. The printing unit 3 of the image forming unit 1 is made of, for example, an aluminum plate having a thickness of 1 mm, and includes a counter electrode 25 facing the outer peripheral surface of the toner carrier 22, a high-voltage power supply 30 for supplying a high voltage to the counter electrode 25, A control electrode 26 provided between the toner carrier 22 and the charge removing brush 28 and the charge removing brush 2
A charging brush 8 for charging the paper 5; a charging power supply 18 for charging the charging brush 8; a dielectric belt 24; and a supporting member for supporting the dielectric belt 24. 16a and 16b and a cleaner blade 19 are provided.

The counter electrode 25 is connected to the toner carrier 22.
Is provided so that the distance from the outer peripheral surface thereof is, for example, 1.1 mm. The dielectric belt 24 is made of PVDF and has a volume resistivity of 1010 Ω · cm and a thickness of 75 μm. The dielectric belt 24 is driven by a driving device (not shown), and rotates at a speed of, for example, 30 mm / sec on its surface in the direction of the arrow in the figure.

A high voltage of, for example, 2.3 kV is applied to the counter electrode 25 by a high voltage power supply (control means) 30. That is, the toner 21 carried on the toner carrier 22 is applied between the counter electrode 25 and the toner carrier 22 by the high voltage applied from the high voltage power supply unit 30.
The electric field required to fly in the direction is provided.

The neutralization brush 28 is provided on the downstream side of the control electrode 26 in the rotation direction of the dielectric belt 24 so as to be in pressure contact with the dielectric belt 24. The neutralizing brush 28 is applied with a neutralizing potential of 2.5 kV by the neutralizing power source 17 to neutralize unnecessary charges existing on the surface of the dielectric belt 24. The cleaning blade 19 removes the toner 21 when an unexpected situation such as a paper jam (paper jam) occurs and the toner 21 adheres to the surface of the dielectric belt 24, and removes the toner 21 from the toner back surface. 21 to prevent contamination.

The material of the counter electrode 25 is not particularly limited. Further, the counter electrode 25 and the toner carrier 2
The distance to 2 is not particularly limited. further,
The rotation speed of the counter electrode 25 and the applied voltage are not particularly limited.

Although not shown, the present image forming apparatus comprises:
As a control circuit, a main control unit that controls the entire image forming apparatus, an image processing unit that converts the obtained surface image data into a format of image data to be printed, and an image memory that stores the converted image data. And an image forming control unit for converting image data obtained from the image processing section into image data to be given to the control electrode 26.

The above-mentioned control electrode 26 is two-dimensionally spread in parallel with the counter electrode 25 and opposed to the counter electrode 25, and has a structure capable of passing toner from the toner carrier 22 toward the counter electrode 25. It has become.

The electric field applied to the surface of the toner carrier 22 changes depending on the potential supplied to the control electrode 26, and the toner 2 from the toner carrier 22 to the counter electrode 25
1 is controlled. The control electrode 26 is provided so that the distance from the outer peripheral surface of the toner carrier 22 is, for example, 100 μm, and is fixed by a support member (not shown).

As shown in FIG. 3, the control electrode 26 includes an insulating substrate 26a, a high-voltage driver (not shown), and independent ring-shaped conductors, that is, ring-shaped electrodes 27. . The substrate 26a is made of, for example, a polyimide resin and has a thickness of 25 μm.

The substrate 26a has a gate 2 to be described later.
9 are formed. Ring-shaped electrode 27
Are made of, for example, a copper foil having a thickness of 18 μm, are provided around the holes, and are arranged according to a predetermined arrangement. The opening of each hole has a diameter of, for example, 160 μm, and serves as a passage for the toner 21 flying from the toner carrier 22 to the counter electrode 25.

Hereinafter, this passing portion is referred to as a gate 29.

The distance between the control electrode 26 and the toner carrier 22 is not particularly limited. Each ring-shaped electrode 27 is provided with an opening having an opening diameter of 200 μm. Also, the size of the gates 29 and the substrate 26a
The material and thickness of the ring-shaped electrodes 27 are not particularly limited. For example, 2560 holes are formed in the gates 29, that is, in the ring-shaped electrodes 27. Each of the ring-shaped electrodes 27 is connected to a control power supply via a power supply line 41 and a high-voltage driver (not shown). It is electrically connected to the unit 31.

The number of ring electrodes 27 is not particularly limited. The surface of the ring-shaped electrode 27 and the surface of the feeder line 41 are covered with a 30 μm thick
c (described later), thereby insulating the ring-shaped electrodes 27 from each other, insulating the power supply lines 41 from each other, and connecting the ring-shaped electrodes 27 and the power supply lines 41 that are not connected to each other. And the insulation between the toner carrier 22 and the counter electrode 25 are ensured. The control power supply unit (control means) 31 is provided on the ring-shaped electrodes 27 of the control electrode 26.
, A pulse corresponding to the image signal, that is, a voltage is applied.

That is, the control power supply section 31 applies the toner 2 carried on the toner carrier 22 to the ring-shaped electrodes 27.
When 1 is passed in the direction of the counter electrode 25 (hereinafter referred to as ON potential), for example, 150 V is applied, and when not passed (hereinafter referred to as OFF potential), for example, -200 V is applied.

As described above, when the potential applied to the control electrode 26 is controlled in accordance with the image signal, and the paper 5 is disposed on the surface of the counter electrode 25 facing the toner carrier 22, the image signal is applied to the surface of the paper 5. Is formed in accordance with.

The control power supply 31 is controlled by a control electrode control signal sent from an image forming control unit (not shown). The image forming apparatus described above can be used not only as a printer for outputting from a computer or a word processor, but also for a printing portion of a digital copy.The following describes an image forming operation when used as a printing portion of a digital copy. This is performed using FIG.

First, for example, when a document to be copied is placed on the image reading unit and a copy start button (not shown) is operated, the main control unit receiving this input starts an image forming operation. That is, a document image is read by the image reading unit, the image data is processed by the image processing unit, and the image data stored in the image memory stored in the image memory is transferred to the image forming control unit. The image forming control unit starts converting the input image data into a control electrode control signal to be applied to the control electrode 26 (S40).
To S44).

When a predetermined amount of the control electrode control signal is obtained, the image forming control unit operates a drive unit (not shown), and the sheet cassette is driven by the pickup roller 6 shown in FIG. The sheet 5 in the sheet feeding unit 4 is sent out toward the image forming unit 1, and the sheet feeding sensor detects that the sheet is in a normal sheet feeding state. The paper 5 sent out by the pickup roller 6 is charged by a charging brush 8
And between the support member 16. The same potential as the counter electrode 25 is applied to the support member 16a by the high voltage power supply 30.

A charging potential of 1.2 kV is applied to the charging brush 8 by a charging power supply 18. The paper 5 is supplied with the electric charge due to the potential difference between the charging brush 8 and the support member 16a, and is conveyed to the surface of the printing unit 3 of the image forming unit 1 facing the control electrode 26 of the dielectric belt 24 while being electrostatically attracted. .

The predetermined amount of the control electrode control signal differs depending on the configuration of the image forming apparatus. Thereafter, the image forming control unit supplies the control electrode control signal to the control power supply unit 31. The supply of the control electrode control signal is performed at a timing synchronized with the supply of the paper 5 to the printing unit 3 by the charging brush 8 described above. The control power supply unit 31 controls a high voltage applied to each ring-shaped electrode 27 of the control electrode 26 based on the control electrode control signal.

That is, a potential of 150 V or -200 V is applied to the predetermined ring-shaped electrode 27 from the control power supply 31 as appropriate, and the electric field near the control electrode 26 is controlled. That is, at the gate 29 of the control electrode 26, the toner 2 is transferred from the toner carrier 22 to the counter electrode 25 in accordance with the image data.
Blocking of the flight 1 and its release are appropriately performed.

As a result, the movement of the dielectric belt 24 on the surface of the counter electrode 25 causes a distance of 30 mm / s toward the paper output side.
A toner image corresponding to the image signal is formed on the paper 5 moving at the speed of ec. Paper 5 on which toner image is formed
Is separated from the dielectric belt 24 at the porosity of the support member 16b, and is conveyed to the fixing unit 11;
At 1, the toner image is fixed on the sheet 5. The paper 5 on which the toner image has been fixed is discharged onto a paper tray by a paper discharge roller, and a normal discharge is detected by a paper discharge sensor. Based on this detection operation, the main control unit determines that the printing operation has ended normally (S46 to S52).

By the above image forming operation, a good image is formed on the paper 5. In the present image forming apparatus, an image is formed directly on the paper 5, so that a visual object such as a photoconductor or a dielectric drum used in a conventional image forming apparatus is not required. Therefore, the transfer operation of transferring the image from the visualized object to the sheet 5 is omitted, so that the image does not deteriorate. For this reason, the reliability of the device is improved.

Further, the configuration of the apparatus is simplified, and
Since the number of parts is reduced, the size and cost can be reduced.

Whether the image forming apparatus of the above embodiment is used as a print portion of an output terminal of a computer or a digital copy,
Although there is a difference in the image signal to be processed and the exchange, the image forming operation method itself has no difference. As described above, the toner carrier 22 is grounded, while the opposing electrode 25 and the support member 16a are 2.3 k
V, a high voltage of 1.2 kV is applied to the charging brush 8.

Therefore, a negative charge is supplied to the surface of the sheet 5 conveyed between the charging brush 8 and the dielectric belt 24 due to the potential difference between the charging brush 8 and the support member 16a. When a negative charge is supplied, the paper 5 is moved directly below the gate 29 by the movement of the dielectric belt 24 while being attracted to the dielectric belt 24 by the electrostatic force of the charge. The electric charge on the surface of the dielectric belt 24 is attenuated with time until it reaches just below the gate 29, and the surface potential becomes 2 kV due to the electric potential of the counter electrode 25.

In this state, the control power supply unit 31 controls the ring-shaped electrode 27 of the control electrode 26 so that the toner 21 carried on the toner carrier 22 passes in the direction of the counter electrode 25.
Are applied, and if the toner 21 does not pass through the gate 29, a potential of -200V is applied.

As described above, an image is directly formed on the surface of the sheet 5 while the sheet 5 is attracted to the dielectric belt 24. In the above description, the potential applied to the ring electrodes 27 of the control electrode 26 to allow the toner 21 to pass therethrough is 15
Although the case of 0 V has been described as an example, the potential is not particularly limited as long as the desired flight control of the toner 21 can be performed. Similarly, the potential applied to the counter electrode 25 and the charging brush 8
And the surface potential of the sheet 5 immediately below the gate 29 are not particularly limited as long as the desired flight control of the toner 21 can be performed.

The potential applied to the ring electrodes 27 of the control electrode 26 to prevent the passage of the toner 21 is not particularly limited as long as it does not deviate from the scope of the present invention.

Control electrode 26 used in the above embodiment
An explanation will be added on the configuration and the like.

FIG. 3 shows the gate portion of the control electrode 26. A high-voltage driver for switching and controlling the ON potential and the OFF potential is disposed on the control electrode 26.

FIG. 5 shows this situation.

FIG. 5 shows one of the gates 29 and one channel of the driver.

FIG. 6 shows a section taken along the line A-AA in the figure.

As shown in FIG. 6, a power supply line 41 and a protective layer 26c are arranged on a polyimide substrate 26a by an adhesive layer 26b. In this embodiment, an epoxy resin mixed with glass fiber is used as the protective layer 26c. As in this embodiment, a material having high thermal conductivity may be mixed in, but a resin having high thermal conductivity capable of forming a thin layer may be used alone. In the configuration of this embodiment, a member having good thermal conductivity is used as the protective layer 26c as described above. As a result, heat generated from the driver 118 is transmitted to the entire surface of the control electrode 26 by the protective layer 26c, and is radiated from the entire surface of the control electrode 26 into the air.

Since the area of the control electrode 26 that contacts the outside air is very large, the temperature rise of the driver 118 and the control electrode 26 due to the heat generated by the driver 118 can be easily avoided, and all the above-mentioned problems can be avoided.

FIG. 7 shows another embodiment of the control electrode 6.

In FIG. 7, a portion that contacts the power supply line 41 is configured to penetrate through the adhesive layer 26b to form a protective layer 26c that can conduct heat with the power supply line 41. Driver 11
Since the heat generated from 8 is conducted by the power supply line 41, it can be configured as shown in FIG.

In the configuration as shown in FIG. 7, since the heat inside the control electrode 26 can be reliably radiated, the temperature rise of the control electrode 26 can be easily avoided. Although the protective layer 26c and the driver 118 are not in direct contact in FIG. 7, the protective layer 26c and the driver 118 may be in direct contact as shown in FIG.

FIGS. 6 to 8 show the case where the protective layer 26c itself has no adhesive ability and it is difficult to form a layer directly on the power supply line 41 or the like.
In the case where the protective layer 26c can be formed directly on, for example, the structure shown in FIG. In the configuration of FIG. 9, since the protective layer 26c is in contact with both the power supply line 41 and the driver 118, the heat generated from the driver 118 can be more efficiently radiated, and the control electrode 26 does not stay inside the control electrode 26. No temperature rise of 26 occurs. Further, in this embodiment, the control electrode 26 is formed integrally with the toner supply unit 2.

In this embodiment, the housing of the toner supply unit 2 is made of aluminum. With this configuration, heat generated from the driver 118 is transmitted to the toner supply unit 2 via the protective layer 26c, so that the area capable of dissipating heat is increased and the heat dissipating effect is further improved.

In the above embodiment, the flying control of the toner 21 of the gate 29 has been described in the case of the control electrode 26 by the single drive in which each gate 29 is controlled by one electrode, but the control electrode 26 by the matrix control as shown in FIG. The present invention can be similarly applied to the case where is used, and good image formation becomes possible.

In FIG. 10, band electrodes 27a and 27b are arranged in place of the ring electrodes 27. A band electrode 27b is disposed on the toner carrier 22 side of the control electrode 26, and a band electrode 27a is disposed on the counter electrode 25 side.

The control layer 26 shown in FIG. 10 may be provided with the protective layer 26c having the structure shown in FIGS. 6 to 9, that is, the protective layer 26c may be provided on one of the two electrode layers. The heat dissipation effect cannot be expected so much for the other electrode layer, and heat may be accumulated in the other electrode layer to cause a temperature rise. In this case, thermal expansion occurs only in the electrode layer, and the above-mentioned problem easily occurs. Therefore, it is preferable to dispose the protective layer 26c on both of the two electrode layers as shown in FIGS.

The above problem has been described by taking the case of a black and white image forming apparatus as an example, but it becomes more pronounced in the case of a color image forming apparatus. The color image forming apparatus includes a plurality of toner supply units 2a, 2b, 2c, 2d,.
, an image forming unit 1 provided with a, 3b, 3c, 3d,.
a, 1b, 1c, 1d,..., and color toners, for example, yellow, magenta, cyan, and black as shown in FIG. A color image forming apparatus may be formed.

In FIG. 15, yellow, magenta, cyan,
The image forming units 1a, 1b, 1c, and 1d according to the present invention are arranged corresponding to black, respectively, and color images are formed based on color image data. Other components may have the same configuration as in FIG. According to the present invention, the above-mentioned problems do not occur at all, so that desired color reproduction and good color image formation can be obtained.

In this embodiment, the case where the developer is a toner has been described as an example, but the developer may be an ink or the like. Further, the configuration of the toner supply unit 2 may be a configuration to which an ion flow method is applied.

That is, the image forming section may be provided with an ion source such as a corona charger. Also in this case, the same operation and effect as described above can be obtained. In the present embodiment, the case where the developer is toner is described as an example, but the developer may be ink or the like.

The image forming apparatus according to the present invention
The printing unit of digital copiers and facsimile machines,
It can be suitably applied to digital printers, plotters and the like.

[0077]

According to the first aspect of the present invention, the temperature rise due to heat generation of the control circuit means disposed on the control electrode is avoided by using the control electrode as described above, so that the temperature can be reduced without using a separate cooling means. Problems due to ascent can be avoided.

According to the second aspect of the present invention, as described above, heat is released by bringing the member having high thermal conductivity into direct contact with the switching means and / or the control circuit means, so that more efficient heat release can be obtained.

According to the third aspect of the present invention, as described above, the high-thermal-conductivity member is brought into contact with the power supply line for transmitting the potential applied to the electrode disposed on the gate, so that the heat generated from the control circuit via the power supply line is generated. Is not conducted without the control electrode, and the heat inside the control electrode can be radiated through the power supply line.

According to the structure of the fourth aspect, since the high thermal conductivity member is used for the protective layer of the control electrode as described above, the control electrode can be configured more simply, the number of parts can be reduced, and the device can be reduced. It is possible to reduce the size and cost of the device.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a cross section of a printer having a printing unit according to an embodiment.

FIG. 2 is a diagram illustrating a concept of a main part of an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating control electrodes of the image forming apparatus.

FIG. 4 is a diagram illustrating a flow of a printing operation.

FIG. 5 is an enlarged view of one channel of a control electrode.

FIG. 6 is a cross-sectional view illustrating a configuration of a control electrode.

FIG. 7 is a diagram (part 1) illustrating another embodiment of the present invention.

FIG. 8 is a diagram (part 2) illustrating another embodiment of the present invention.

FIG. 9 is a diagram (part 3) illustrating another embodiment of the present invention.

FIG. 10 is a diagram illustrating another form of the control electrode.

FIG. 11 is a diagram illustrating a configuration of a control electrode in another embodiment of the control electrode.

FIG. 12 is a diagram (part 4) explaining another embodiment of the present invention.

FIG. 13 is a view (No. 5) explaining another embodiment of the present invention.

FIG. 14 is a view (No. 6) explaining another embodiment of the present invention.

FIG. 15 is an explanatory diagram illustrating a color image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming part 2 Toner supply part 10 Paper feeder 11 Fixing part

Claims (4)

[Claims] 1. A supply unit having a carrier for carrying a developer of at least one color, a counter electrode arranged opposite to the carrier, and a high electrode for generating a potential difference between the carrier and the counter electrode. A high-voltage power supply for supplying a voltage; an insulating substrate disposed between the carrier and the counter electrode; a plurality of gates provided on the insulating substrate as passage portions for a developer; A control electrode comprising at least one or more electrode groups provided around the gate of the control electrode and control means comprising control circuit means for providing a plurality of potential states of each electrode of the control electrode, Means for controlling the passage of the developer through the gate by applying a predetermined potential to the corresponding electrodes of the electrode group by means, and forming an image on the surface of the recording medium conveyed to the counter electrode. The above control circuit The stage includes switching means for switching the potential state of the control electrode, and at least the switching means is disposed on the control electrode, wherein the switching means or the switching means using at least the switching means or the control circuit means as a heat source. An image forming apparatus, wherein temperature rise of at least one of control circuit means or control electrodes is avoided by using the control electrodes. 2. The image forming apparatus according to claim 1, wherein said control electrode has a high thermal conductivity member that contacts said switching means or control circuit means or both. 3. The image forming apparatus according to claim 1, wherein the control electrode has a high thermal conductivity member that contacts a power supply member connected to the switching unit. 4. An image forming apparatus according to claim 1, wherein said high thermal conductive member is a protective layer disposed on the outermost surface of said control electrode.