JPH11301012A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To well hold an image forming state of a color image or the like by accurately controlling the relative positional relation of the toner flown from a plurality of toner carriers on a recording medium. SOLUTION: The same number of passing holes 22 are formed to the respective flight control parts 2a, 2b opposed to separate toner carriers and the passing holes 22 of the flight control part 2a and those of the flight control part 2b are alternately arranged in the direction crossing the feed direction of a recording medium at a right angle and deflection electrodes 26a-26c to which deflection voltages are applied mutually independently are provided to the edge parts of the respective passing holes 22. By controlling the relation of the applied states of deflection voltages to the deflection electrodes 26a-26c contained in the flight control parts 2a, 2b, the relative relation of the toner flight directions in the passing holes 22 contained in the respective flight control parts 2a, 2b is adjusted and the toner passed through all of the passing holes 22 is positioned at an equal interval in the direction crossing the feed direction of the recording medium at a right angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which toner carried on a plurality of toner carriers arranged in parallel in the transport direction of a recording medium is caused to fly onto the recording medium via a through hole in which a flying electric field is formed. The present invention relates to an image forming apparatus for forming an image.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a digital copying machine, a method of forming a visible image on a recording medium based on an image signal, a method of flying ink, a method of melt-transferring ink, and a method of transferring ink are used. A sublimation method and an electrophotographic method using toner are known. Of these, the so-called ink jet method of flying ink has a simple device configuration and meets the demands for high speed, high image quality, and low price, but the use of liquid ink tends to cause bleeding on the recording medium. In addition, there is a difficulty in storing the ink due to the problem of solidification, and it is not suitable for an environment in which a large amount of images are formed. For this reason, in the case of forming a large amount of images or color images, an electrophotographic method using toner is generally adopted.

However, in electrophotographic image formation,
Powder toner is easy to store, does not cause bleeding on the recording medium, and the color mixture during color image formation is performed in the heating and pressing fixing process, so that the mixture color can be easily controlled. On the other hand, there is a problem that a structure for performing a number of steps is complicated and the apparatus is enlarged.

In view of the above, a large number of image forming apparatuses of the direct recording type using the toner flying in which an ink jet type process is performed using toner have been proposed. For example, Japanese Patent Publication No. 1-503221 discloses that a charge image is formed near a wire by selectively applying a voltage to a plurality of wires arranged in a matrix, and toner is applied to the charge image. A method for forming a toner image is disclosed. In Japanese Patent Application Laid-Open No. Hei 6-305178, an opening is formed in parallel with the transport direction of a recording medium.
A plurality of pairs of control electrodes are arranged in the longitudinal direction with the opening interposed therebetween, and a voltage is independently applied to each of the plurality of pairs of control electrodes to control the toner flow passing through the opening in a plurality of stages. There is disclosed a configuration for improving the resolution of an image.

Further, Japanese Patent Application Laid-Open No. 6-234233 discloses that a plurality of developing devices containing toners of respective colors are arranged in the direction of conveyance of a recording medium, and a plurality of developing devices are provided on a substrate facing the plurality of developing devices. There is disclosed a configuration in which a toner passage hole is formed and the passage of toner in each toner passage hole is controlled according to an image signal. In addition, JP-A-8-13
Japanese Patent No. 2663 discloses a common substrate having a toner passage hole having a control electrode corresponding to each of a plurality of toner tanks accommodating toner of each color in a conveying direction of a recording medium, and a back electrode corresponding to each toner tank. To control the voltage application state to the control electrode and the back electrode to selectively form a flying electric field for causing the toner from the toner tank to fly on the recording medium conveyed between the control electrode and the back electrode. An arrangement is disclosed.

[0006]

However, when a color image is formed by mixing a plurality of color toners in an image forming apparatus of the direct recording type, the toner of each color is transferred from a toner carrier for each color through a passage hole. And accurately fly to the same position on the surface of the recording medium, and control the relative flying position of the toner of each color flying from each of the plurality of toner carriers on the surface of the recording medium with high precision. There is a need. Further, when forming a monochromatic image, a plurality of toner carriers are arranged in parallel in the transport direction of the recording medium, and the through holes facing each of the plurality of toner carriers are arranged in a direction orthogonal to the transport direction of the recording medium. In some cases, the resolution may be increased by displacing the positions. In this case, it is necessary to control the relative positional relationship of the toner flying from each of the plurality of toner carriers on the surface of the recording medium with high accuracy. is there.

In this respect, the configuration disclosed in Japanese Patent Application Laid-Open No. 6-35274 can deflect the ion flow in the opening range in the transport direction of the recording medium for each pixel, but the toner particles having a constant mass. The flying direction of the toner cannot be sufficiently deflected due to the kinetic energy for flying the toner or the adhesion of the toner to the electrodes. Further, in the configuration disclosed in JP-A-6-316101, since both control electrodes are arranged on the same plane, the electrode that deflects the toner flying direction is shielded by the electrode that generates the toner flow, There is a problem that the flying direction of the toner cannot be sufficiently deflected.

Further, as disclosed in JP-A-6-305178, in a configuration in which a plurality of pairs of control electrodes are arranged at the edge of an opening formed long in the recording medium conveyance direction, the length of the opening is reduced. There is a problem that the toner tends to leak in the direction and the electrodes are complicated. Also, JP-A-6-2
As disclosed in Japanese Patent Application Laid-Open No. 34233/34, the configuration in which the accuracy of the flying position of the toner of each color is improved by integrating the electrode portions of the toner tanks of a plurality of colors is disclosed. In the configuration in which the passage hole diameter and the control voltage are determined so that the optimal amount of toner is obtained for each color, a control electrode is formed at an appropriate position on a substrate, and the substrate is It is necessary to attach the toner tank to a proper position with respect to the toner tank, and there has been a problem that the operation of manufacturing parts and the operation of assembling the apparatus become extremely complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a direct recording type image forming method in which toner is ejected from a plurality of toner carriers, and the relative positional relationship of the toner ejected from the plurality of toner carriers on a recording medium. It is an object of the present invention to provide an image forming apparatus which can easily and accurately control the color image and high-resolution image forming state.

[0010]

According to the first aspect of the present invention, a flying electric field is selectively formed in a plurality of through holes facing each of a plurality of toner carriers arranged in parallel in a moving direction of a recording medium. In an image forming apparatus that forms an image by flying toner carried by each toner carrier onto a recording medium via a passage hole in which a flying electric field is formed, a plurality of areas are provided at each edge of the plurality of passage holes. A voltage for controlling a voltage application state to each of the plurality of ranges of the control electrode according to a relative positional relationship of the toner flying from each of the plurality of toner carriers on the recording medium is arranged. A control means is provided.

According to the first aspect of the present invention, the control electrode divided into a plurality of ranges is arranged at each edge of the passage hole facing each of the plurality of toner carriers.
The voltage application state to each of the control electrodes divided into a plurality of ranges is controlled according to the relative positional relationship of the toner flying from each of the plurality of toner carriers on the recording medium. By changing the voltage value applied to each of a plurality of ranges of the control electrode arranged at the edge of each passing hole, the direction of the flying electric field formed in the passing hole changes, and the flying via the passing hole The flying direction of the falling toner is deflected. Accordingly, each of the plurality of ranges of the control electrode has a voltage for deflecting the flying direction of the toner so that the toner flying from each of the plurality of toner carriers achieves a predetermined relative positional relationship on the recording medium. Is applied, and the relative positional relationship of the toner flying from each of the plurality of toner carriers on the recording medium is maintained in a predetermined state.

According to a second aspect of the present invention, a first control electrode divided into a plurality of ranges is disposed at an edge of each of the plurality of passage holes on the side of the recording medium and an edge of the toner carrier on the side of the toner carrier. A second control electrode is disposed, and a voltage application state to each of the plurality of ranges of the first control electrode is controlled according to a relative positional relationship of the toner flying from each of the plurality of toner carriers on the recording medium. And a voltage control means for controlling a voltage application state to the second control electrode according to the image signal.

According to the second aspect of the present invention, the first control electrode divided into a plurality of ranges is disposed at the edge of the through hole on the recording medium side, and at the edge of the through hole on the toner carrier side. A second control electrode is disposed, and the toner flying from each of the plurality of toner carriers in each of the plurality of ranges of the first control electrode is arranged such that the toner has a predetermined relative positional relationship on the recording medium. A voltage for deflecting the flight direction is applied, and a voltage corresponding to the image signal is applied to the second control electrode. Therefore, the toner selectively flying from each toner carrier in accordance with the image signal due to the flying electric field formed by the second control electrode causes the other toner carrier to fly due to the flying electric field formed by the first control electrode. It flies in a direction that achieves a predetermined relative positional relationship between the toner that flies from the body and the recording medium.

According to a third aspect of the present invention, the voltage control means applies a common voltage to each of a plurality of ranges of the first control electrode with respect to a plurality of passage holes facing a single toner carrier. It is characterized by the following.

According to the third aspect of the present invention, a common voltage is applied to each of the plurality of through holes arranged opposite to the single toner carrier with respect to each range of the first control electrode. Applied. Therefore, the flying direction of the toner is deflected in a fixed direction in all the passage holes facing the single toner carrier, and the toner is controlled by a single voltage control means for all the passage holes facing the single toner carrier. The flight direction is controlled.

According to a fourth aspect of the present invention, the voltage control means includes an image reading means for reading an image formed on a recording medium via each of a plurality of toner carriers, and the read result of the image reading means is provided. The voltage application state to the control electrode is controlled based on the control signal.

In the present invention, the state of voltage application to the control electrode is controlled based on the result of reading an image formed on the recording medium via each of the plurality of toner carriers. Therefore, the voltage application state to the control electrode is controlled so that the relative positional relationship of the image formed by each of the plurality of toner carriers on the recording medium is proper.

According to a fifth aspect of the present invention, the voltage control means controls a voltage value to be applied to the control electrode and a voltage application timing based on a reading result of the position detection pattern image. It is characterized by the following.

According to the fifth aspect of the present invention, a voltage value to be applied to the control voltage and a voltage application to the control voltage based on a result of reading an image formed on the recording medium via each of the plurality of toner carriers. Timing is controlled. By controlling the voltage applied to each of the divided control electrodes, the flying direction of the toner is deflected, and the flying position of the toner in the transport direction of the recording medium and in the direction perpendicular to the transport direction changes. Further, by controlling the timing of applying the voltage to the control electrode, the flying position of the toner in the transport direction of the recording medium changes. Therefore, the flying direction of the toner in the recording medium transport direction and the direction perpendicular to the transport direction is controlled so that the relative positional relationship of the image formed by each of the plurality of toner carriers on the recording medium is appropriate. You.

[0020]

FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a configuration near a printing unit of the image forming apparatus. FIG. 3 is a plan view and a partially cutaway perspective view of a flight control unit constituting the printing unit, and FIG. 4 is a diagram showing a configuration of a control unit of the image forming apparatus. The image forming apparatus 10 is an image forming apparatus that forms a high-resolution monochromatic image, and includes a printing unit 1, a paper feeding unit 4, a fixing unit 6, and a control unit 7. The paper feed unit 4 includes a paper feed cassette 41 mounted on the upper surface of the main body of the image forming apparatus 10, a pickup roller 42 for feeding out the recording media P stored in the paper feed cassette 41 one by one, and A registration roller 42 for guiding the medium P into the printing unit 1 at a predetermined timing is provided. Pickup roller 41 and registration roller 42
Is driven via a drive mechanism (not shown) based on a drive signal output from the control unit 7.

The fixing unit 6 detects a temperature of the cylindrical heat roller 62 containing a heater 61 such as a halogen lamp therein, a pressure roller 63 which comes into contact with the heat roller 62 at a predetermined pressure, and a temperature of the heat roller 62. Temperature sensor 64
The on / off control of the heater 61 based on the detection signal of the temperature sensor 64 maintains the surface temperature of the heat roller 62 at a temperature at which the toner can be melted. The recording medium P that has passed through the printing unit 1 is guided between the heat roller 62 and the pressure roller 63 in the fixing unit 6,
Subject to heat and pressure. Thus, the toner attached to the surface of the recording medium P is melted and fixed on the surface of the recording medium P.

As shown in FIG. 2, the printing unit 1 includes a toner charger 3 for supplying a predetermined amount of toner T charged to a predetermined polarity and a predetermined value, and the flying of the toner supplied by the toner charger 3. The flight control units 2a and 2b for controlling, the counter electrodes 11a and 11b opposed to the flight control units 2a and 2b with a certain gap therebetween, and the fan 1 for sucking the recording medium P
3a and 13b are arranged in this order from below to above. The counter electrodes 11a and 11b are arranged with a gap of, for example, 1 mm with respect to the peripheral surfaces of the toner carriers 31a and 31b.
A voltage of 5 to 2 kV is applied.

The toner charger 3 for storing the toner T is
Book toner carriers 31a, 31b, two blades 32
a, 32b and two supply rollers 33a, 33b. The toner carriers 31a and 31b are driven via a driving mechanism (not shown), and rotate at a peripheral speed of, for example, 60 mm / sec in a direction indicated by an arrow in FIG. Toner carrier 31
a and 31b form a flying electric field for causing the toner T to fly between the later-described counter electrodes 11a and 11b and the flight controllers 2a and 2b.

On the surfaces of the toner carriers 31a and 31b,
Irregularities of about several μm are formed, and the blades 32a,
The end of 32b is pressed. These blades 32a, 32b
, The toner T is carried on the surfaces of the toner carrying members 31a and 31b. The supply rollers 33a and 33b are driven via a driving mechanism (not shown), rotate in the direction indicated by the arrow in FIG. 2, and agitate the toner T stored in the toner charger 3 to agitate the toner carriers 31a and 33b. 31b. The toner T has, for example, a particle size of 10 mainly composed of styrene acrylic.
It is a powder of about μm, and is charged with a predetermined electric charge by being stirred by the supply rollers 33a and 33b. In this embodiment, as an example, a toner T that charges a negative charge is used.

The recording medium P guided from the paper feed unit 4 to the printing unit 1 by the rotation of the registration roller 43 is supplied to the fan 13a,
With the suction force of 13b, it is conveyed between the opposing electrodes 11a, 11b and the flight controllers 2a, 2b while being attracted to the lower surfaces of the opposing electrodes 11a, 11b. During this time, the toner T selectively flying from the toner carriers 31a and 31b adheres to the lower surface of the recording medium P. The recording medium P having the toner T adhered to the lower surface thereof is heated by a heat roller 62 and a pressure roller 63.
The toner T is melted and fixed on the lower surface of the recording medium P.

An image reading sensor 81 is provided on the sheet discharging side of the fixing unit 6 so as to face the lower surface of the recording medium P passing between the heat roller 62 and the pressure roller 63.
The image reading sensor 81 is connected to a recording medium P as described later.
The pattern image for position detection formed on the image is read.

As shown in FIG. 3, the flight controllers 2a, 2
b denotes a plurality of through holes 22 and power supply electrodes 24 in a base substrate 25 made of, for example, a polyimide resin having a thickness of 25 μm.
And a control electrode 26 are formed. The base substrate 25 is formed by laminating a cover layer 28 on the upper surface and a shield electrode 27 on the lower surface. Cover layer 28
Protects the power supply electrode 24 and the control electrode 26 formed on the upper surface of the base substrate. The shield electrode 27 is connected to the power supply electrode 24 and the counter electrodes 11 a and 11 via the base substrate 25.
The effect of the electric field b on the toner T carried on the toner carrying members 31a and 31b is prevented. The base substrate 25 is parallel to the counter electrodes 11a and 11b,
For example, a gap of 100 μm is provided between the mounting table 21 and the mounting table 21.

The diameter of the control electrode 26 is about 200 μm, and the diameter of the passage hole 22 is about 160 μm. As an example, in the flight control unit 2a in the base substrate 25, four through holes 22 are provided in the direction inclined at a predetermined angle with respect to the conveying direction of the recording medium P, and 640 in the direction orthogonal to the conveying direction of the recording medium P. The through holes 22a-1 to 22a-2560 are formed in total. That is, in this example, the A4 size recording medium P conveyed in the longitudinal direction is
On the other hand, the number of the passing holes 22 corresponding to the resolution of 300 DPI is formed, and the interval between the passing holes 22 in the direction orthogonal to the conveying direction of the recording medium P is 1/300 inch (85 μm). I have.

In the flight control unit 2b, the flight control unit 2
a total of 2560 through holes 22b-
1 to 22b-2560 are formed. However, the passage holes 22a-1 to 22a-2560 of the flight control unit 2a and the passage holes 22b-1 to 22b-2560 of the flight control unit 2b are 1/600 in the direction orthogonal to the conveyance direction of the recording medium P.
It is displaced by an inch (42 μm). Therefore, the passage holes 22 face the lower surface of the recording medium P at an interval of 1/600 inch in the direction orthogonal to the conveyance direction while the recording medium P is conveyed in order to face the flight control unit 2b and the flight control unit 2a. That is, an image is formed at a resolution of 600 DPI.

In each of the flight controllers 2a and 2b, the control electrode 26 is formed at a position surrounding each edge of the 2560 passage holes 22. Each control electrode 26
Are constituted by deflection electrodes 26a to 26c in a range that divides the periphery of the edge of the passage hole 22 into three. In addition, the power supply electrode 24 includes deflection electrodes 26 a to 26
26c and deflection electrode power supplies 76a to 76 to be described later.
and c.

The distance between the toner carrying members 31a, 31b and the flying electrode portions 2a, 2b and the opposing electrodes 11a, 1b,
The opening diameter of the passage hole 22, the electrode diameter of the control electrode 26, the voltage applied to the counter electrodes 11a and 11b, and the base substrate 2
The configuration of No. 5 can be appropriately determined depending on the composition of the toner T, the type of the recording medium P, and the like.

As shown in FIG. 4, the control unit 7 is divided into control units 7a and 7b corresponding to the flight control units 2a and 2b, respectively. The control unit 7a and the control unit 7b
Have the same configuration, and the control unit 7a will be described here. The control unit 7a includes a CPU 71, a shift register 72, a deflection electrode driver 74, a counter electrode power supply 75, and deflection electrode power supplies 76a to 76c. CPU 71
Are the counter electrode power supply 75 and the deflection electrode power supplies 76a to 76c.
Output a control signal to the controller. The shift register 72
An operation signal is output to the deflection electrode driver 74 at a timing corresponding to the image signal.

The counter electrode power supply 75 is connected to the counter electrode 11 during a printing operation based on a control signal output from the CPU 71.
A voltage of 2 kV is applied to a and 11b. Deflection electrode power supply 7
6a to 76c are the power supply electrode 24 and the deflection electrode driver 7;
4 are connected to the deflection electrodes 26a to 26c, respectively, and are supplied from the CPU 71 to deflection electrode power supplies 76a to 76c.
And outputs a deflection voltage set by a control signal individually output to each of the above. The deflection driver 74 supplies the deflection voltage output from the deflection electrode power supplies 76a to 76c to each of the deflection electrodes 26a to 26c based on the operation signal output from the shift register 72.

It should be noted that only one set of deflection electrode power supplies 76a to 76c can be provided for all control electrodes 26 formed in 2560 passage holes 22 formed in the flight control section 2a. As a result, the same deflection voltage application state is set for all of the control electrodes 26 formed in each of the 2560 through holes 22 included in the flight control unit 2a. On the other hand, the deflection electrode driver 74
The deflection voltage is provided for each of the through holes 22 included in the control electrode 26, and a deflection voltage is selectively applied to the control electrodes 26 formed in each of the through holes 22a-1 to 22a-2560 according to the image signal.

FIG. 5 is a diagram showing an image forming state in the image forming apparatus. In the image forming apparatus 10 configured as described above, a predetermined voltage is applied to the opposing electrodes 11a and 11b from the opposing electrode power supply 75 of the control units 7a and 7b, and the passing holes 2 selected by the deflection electrode driver 74 are applied.
When a deflection voltage set by the deflection electrode power supplies 76a to 76c is applied to the deflection electrodes 26a to 26c formed in the second electrode 2, the toner carriers 31a, 31b are transferred from the toner carrying members 31a, 31b to the counter electrodes 11a, 11b in the through holes 22 to which the deflection voltage is applied. Is formed, and the toner T carried on the surfaces of the toner carrying members 31a and 31b flies in the direction of the counter electrodes 11a and 11b via the passage holes 22 in the flight controllers 2a and 2b. 11b and the flight controllers 2a and 2b
, The toner T adheres to the surface of the recording medium P existing between them.

As a result, the toner T flying from the toner carrier 31a via the flight controller 2a and the toner T flying from the toner carrier 31b via the flight controller 2b
And an image having a resolution of 600 DPI is recorded on the recording medium P.
Formed. Therefore, in order to accurately form an image at a predetermined resolution on the recording medium P, the toner T flying from the toner carrier 31a and the toner T flying from the toner carrier 31b are separated by a predetermined resolution corresponding to the set resolution. It is necessary to alternately position the recording medium P in the direction orthogonal to the conveying direction of the recording medium P at intervals of.

Therefore, in the image forming apparatus 10, the position detecting pattern image formed on the recording medium P is read by the image reading sensor 81, and the control units 7a and 7b output control signals from the CPU 71 based on the read result. By changing the voltage value of the deflection voltage set in the deflection electrode power supplies 76a to 76c via the signal, the toner T flying from the toner carrier 31a and the toner T flying from the toner carrier 31b are set to the set resolution. The relative positional relationship between the recording media P and the recording medium P is adjusted so that the recording media P are alternately positioned at predetermined intervals in the direction orthogonal to the conveying direction.

That is, the direction of the flying electric field that determines the flying direction of the toner T from the toner carriers 31a, 31b to the opposing electrodes 11a, 11b depends on the value of the deflection voltage applied to each of the deflection voltages 26a to 26c. Change.
Therefore, by changing the application state of the deflection voltage to the deflection voltages 26a to 26c in the flight control unit 2a and the flight control unit 2b, recording of the toner T flying from the toner carrier 31a and the toner T flying from the toner carrier 31b is performed. The relative positional relationship on the surface of the medium P can be adjusted.

For example, the flight controller 2a is controlled by the controller 7a.
Electrodes 26a-26 formed in the passage holes 22a-1
A bias voltage of +250 V is applied to the recording medium P, and 380 μm from the passage hole 22a-1 in the conveying direction of the recording medium P.
m of the flight control unit 2b which should be at a distance of m
By applying a deflection voltage of +250 V from the control unit 7b to the deflection electrodes 26a to 26c formed on the recording medium P, a pattern image for position detection composed of two line images L1 and L2 is formed on the surface of the recording medium P. Then, the pattern image is read by the image reading sensor 81. When the interval between the line images L1 and L2 read by the image reading sensor 81 is 400 μm, the CPU 71 of the control unit 7b
As a result, for example, +230 is applied to the deflection electrode power supplies 76a and 76c.
V deflection voltage is set, and for example, +
A deflection voltage of 300 V is set. As a result, the deflection electrodes 26a and 26c formed in the passage hole 22b-5 have +
A deflection voltage of 230 V is applied, and +30 is applied to the deflection electrode 26b.
By performing image formation by applying a deflection voltage of 0 V,
The interval between the line images L1 and L2 formed on the surface of the recording medium P is set to an appropriate value of 380 μm.

The pattern image for position detection is formed outside the printing area of the recording medium P to form a pattern image for position detection for adjusting the deflection voltage simultaneously with the normal image printing process. be able to. In this case, the formation position and the shape of the pattern image for position detection may be, for example, a mark that can be used as a mark of a midpoint position or a ruled line position in the transport direction of the recording medium P or a direction orthogonal to the transport direction.

The deflection voltage applied to the deflection electrodes 26a to 26c constituting each control electrode 26 affects not only the flight direction of the toner T passing through the passage hole 22 but also the flight amount of the toner T. give. Accordingly, the image reading sensor 81 simultaneously detects not only the pattern image forming position but also the image density of the pattern image, and based on the detected image density of the pattern image, the deflection electrode power supplies 76a to 76c of the control units 2a and 2b. The density of the image to be formed may be adjusted by increasing or decreasing the set value of the deflection voltage in.

Further, in the above embodiment, each control electrode 26 is constituted by three deflection electrodes 26a to 26c. However, each control electrode 26 may be constituted by two or four or more deflection electrodes. However, when the control electrode 26 is configured by two deflection electrodes, if the two deflection electrodes are arranged in the transport direction of the recording medium P, the flying direction of the toner T will be perpendicular to the transport direction of the recording medium P. It must be taken into account that it cannot be adjusted.

In addition, in the detection of the toner flying position based on the pattern image read by the image reading sensor 81, the pattern image for position detection, as indicated by a broken line in FIG. Also, the pattern image G1 may be formed on the recording medium P based on the image data of the reference pattern image Ga including a boundary line that is perpendicular to and a boundary line that makes a predetermined angle θ with the conveyance direction of the recording medium P. Good. In this case, the reference pattern image G by the image reading sensor 81
The read signal S1 of FIG. 6A is compared with the reference signal Sa shown in FIG. In this comparison, the rising and falling timings of the read signal S1 of the pattern image G1 are t1 and t3, the rising and falling timings of the reference signal Sa are t0 and t2, the transport speed of the recording medium P is V, and the reference pattern is V. The error ΔX in the direction orthogonal to the transport direction of the recording medium P of the pattern image G1 with respect to the image Ga and the error ΔY in the transport direction of the recording medium P are ΔX = {(t1−t0) − (t3−t2)} × V / ta
nθ ΔY = (t3−t2) × V By storing the error calculated in this way or the deflection voltage value determined corresponding to the error in a nonvolatile memory (not shown) provided in the control unit 7, the nonvolatile memory Is read out, and the application timing of the voltage to the control electrode 26 and the deflection voltage value can be properly determined.

In the conveyance direction of the recording medium P, an error of one pixel can be corrected by controlling the output timing of signals from the CPU 71 and the shift register 72 of the control section 7 to the counter electrode 11 and the deflection electrode driver 74. The error of less than one pixel can be corrected by controlling the voltage value of the deflection voltage set to the deflection electrodes 26a to 26c from the CPU 71.

FIG. 7 is a diagram showing a configuration of an image forming apparatus according to a second embodiment of the present invention, and FIG. 8 is a diagram showing a configuration of a printing unit of the image forming device. The image forming apparatus 10 according to this embodiment includes the print control unit 1 having the flight control units 2a to 2a.
d, toner chargers 3a to 3d, counter electrodes 11a to 11d
And a transfer belt 12. Each of the toner chargers 3a to 33d stores toner of each color of yellow, magenta, cyan, and black. As shown in FIG. 8, each of the toner chargers 3a to 3d includes a toner carrier 31, Blade 32, supply roller 33
And a stirring member 34. Counter electrodes 11a to 11
d are arranged at positions facing the peripheral surface of the toner carrier 31 provided in each of the toner chargers 3a to 3d at a predetermined interval, and are provided at the flight control units 2a to 2d.
The base substrate (not shown) constituting each of the electrodes d is formed on the lower surfaces of the counter electrodes 11a to 11d.
Are arranged in parallel with each other. Transfer belt 12
Are stretched so as to pass between the opposing electrodes 11a to 11d and the flight controllers 2a to 2d.
Is also used as a pressure roller in the fixing unit 6.

With the above configuration, the toner chargers 3a to 3a
d flying from the toner carrier 31 of each of
The color toner T adheres to the surface of the transfer belt 12, and a color image is formed by mixing the four color toners. Recording medium P stored in paper feed cassette 41 in paper feed unit 4
Are fed one by one by the rotation of the pickup roller 42, and are guided into the fixing unit 6 at a timing synchronized with the color image formed on the surface of the transfer belt 12 by the rotation of the registration roller 43. As a result, the four color toners constituting the color image on the transfer belt 12 are transferred to the surface of the recording medium P, and are also melted by being heated and pressed in the fixing unit 6 and fixed on the surface of the recording medium P. After passing the fixing unit 6, the recording medium P is discharged to the upper surface of the apparatus by rotating the discharge roller 65 after the surface on which the toner constituting the color image is fixed faces the image reading sensor 81.

As described above, the image forming apparatus 10
A color image is formed by mixing four color toners stored in each of the three toner chargers 3a to 3d. To obtain faithful reproducibility in the formed color image, For each pixel, the toner carrier 3 provided in each of the toner chargers 3a to 3d
It is necessary that the toner T flying from the position 1 adheres to the same position on the transfer belt 12 accurately.

For this reason, each of the flight controllers 2a to 2d facing the peripheral surface of the toner carrier 31 provided in each of the toner chargers 3a to 3d is, for example, as shown in FIG.
Is configured in the same manner as the flight control unit 2a, and the positions of the passage holes 22 included in each of them are made to coincide in the direction orthogonal to the rotation direction of the transfer belt 12. At the same time, the timing of forming a flying electric field between the toner carrier 31 of each of the toner chargers 3a to 3d and the opposing electrodes 11a to 11d is such that the surface of the transfer belt 12 faces each of the toner chargers 3a to 3d. The timing is matched. Thus, ideally, the surface of the recording medium P is 3
A color image having a resolution of 00 DPI is formed.

However, errors in the mounting positions of the base substrates constituting the flight controllers 2a to 2d and the counter electrodes 11a to 11d
Due to an error in the application timing of the counter voltage to the toner charging device 3a, the adhesion positions of the toner T of each color flying from the toner carrier 31 of each of the toner chargers 3a to 3d on the surface of the transfer belt 12 may not match. If left unattended, the four color toners cannot be mixed accurately in each pixel of the color image, and the color image cannot be faithfully reproduced.

Therefore, a pattern image for position detection is formed on the recording medium P via the transfer belt 12 by each of the four color toners T stored in each of the toner chargers 3a to 3d. The deflection voltage to be applied to the deflection electrodes 26a to 26c included in each of the flight control units 2a to 2d is adjusted based on the reading result of the pattern image read by the image reading sensor 81.
Thereby, the relative positional relationship of the adhesion positions of the toner T flying from the respective toner carriers 3 of the toner chargers 3a to 3d on the surface of the transfer belt 12 is controlled.
By accurately adhering the color toners T to the same position on the surface of the transfer belt 12, it is possible to accurately reproduce the color image by accurately mixing the four color toners in each pixel of the color image. it can.

FIG. 9 is an enlarged cutaway perspective view showing a configuration of a flight control section of an image forming apparatus according to another embodiment of the present invention, and FIG. 10 is a view showing a configuration of a control section of the image forming apparatus. . Flight control unit 2 of the image forming apparatus according to this embodiment
Is a base substrate 2 having a cover layer 28 formed on upper and lower surfaces.
In each of the plurality of through holes 22 formed in 5,
A first control electrode 26 composed of deflecting electrodes 26a to 26c is formed on an edge on the upper surface side of the base substrate 25, which is a counter electrode side, and is formed on an edge on a lower surface side of the base substrate 25 on the toner carrier side. The second control electrode 23 is formed integrally over the entire circumference. Each of the second control electrode 23 and the deflection electrodes 26a to 26d includes:
A voltage is applied independently of the control unit 7.

To the flight controller 2 configured as described above, the controller 7 applies a voltage to the second control electrode 23 for selecting whether or not to fly the toner T, and controls the flying direction of the toner T. The deflection voltage for adjustment is adjusted by the deflection electrodes 26a-26.
c. For example, in the flight control units 2a and 2b in which the passage holes 22 are arranged in the state shown in FIG. 3A, the passage holes 22a-1 and the flight control units 2 included in the flight control unit 2a are included.
b at the passage hole 22b-5 included in the deflection electrode 2
When a voltage of 0 V is applied to 6a to 26c and a voltage of +250 V is applied to the second control electrode 23, and the interval between two line images formed is 410 μm, the passage hole 22
By applying a deflection voltage of +30 V to the deflection electrode 26b of b-5, the distance between the two line images could be made an appropriate value of 380 μm.

As described above, the first control electrode 26 constituted by the deflecting electrodes 26a to 26c is formed at the edge of the passage hole 22 included in the flight control section 2 on the counter electrode side, and the edge on the toner carrier side is formed. By forming the second control electrode 23 in the section, an electric field which deflects the flying direction of the toner for a relatively long distance from the lower surface of the base substrate constituting the flight control section 2 to the surface of the recording medium P acts. Therefore, the flying direction of the toner can be controlled by a relatively low deflection voltage. Further, by controlling the voltage applied to the second control electrode 23, the flying amount of the toner can be reliably controlled.

[0054]

According to the first aspect of the present invention, the control electrode divided into a plurality of ranges is arranged at each edge of the passage hole facing each of the plurality of toner carriers, and the control electrodes are divided into the plurality of ranges. By controlling the voltage application state to each of the divided control electrodes according to the relative positional relationship of the toner flying from each of the plurality of toner carriers on the recording medium, each of the plurality of ranges of the control electrodes is controlled. A voltage for deflecting the flying direction of the toner so that the toner flying from each of the plurality of toner carriers achieves a predetermined relative positional relationship on the recording medium. By properly adjusting the relative positional relationship of the toner flying from each of the bodies on the recording medium, the image forming state of a color image or a high-resolution image is maintained well. Door can be.

According to the second aspect of the present invention, the first control electrode divided into a plurality of ranges is arranged at the edge of the through hole on the recording medium side, and the first control electrode is divided at the edge of the through hole on the toner carrier side. A second control electrode is disposed, and the toner flying from each of the plurality of toner carriers is provided in each of the plurality of ranges of the first control electrode so as to achieve a predetermined relative positional relationship on the recording medium. A voltage for deflecting the flight direction is applied, and a voltage corresponding to the image signal is applied to the second control electrode. A method of realizing a predetermined relative positional relationship in a recording medium between a toner selectively flying from a body and a toner flying from another toner carrier by a flying electric field formed in a first control electrode. It is possible to properly maintain the relative positional relationship of the toner flying from each of the plurality of toner carriers on the recording medium and maintain a good image forming state of a color image or a high-resolution image. it can.

According to the third aspect of the present invention, a common voltage is applied to each range of the first control electrode with respect to each of the plurality of passage holes arranged to face the single toner carrier. By doing so, the flying direction of the toner can be controlled by a single voltage control unit for each toner carrier, and the configuration and control contents of the voltage control unit can be simplified to reduce costs.

According to the fourth aspect of the invention, the state of voltage application to the control electrode is controlled based on the result of reading an image formed on a recording medium via each of the plurality of toner carriers. In addition, it is possible to accurately control the voltage application state to the control electrode for making the relative positional relationship of the image formed by each of the plurality of toner carriers on the recording medium proper.

According to the fifth aspect of the present invention, the voltage value to be applied to the control voltage and the voltage value to be applied to the control voltage are determined based on the result of reading the image formed on the recording medium via each of the plurality of toner carriers. By controlling the application timing, the toner in the transport direction of the recording medium and the direction perpendicular to the transport direction is adjusted so that the relative positional relationship of the images formed by each of the plurality of toner carriers on the recording medium becomes appropriate. Can be accurately controlled.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration near a printing unit of the image forming apparatus.

FIG. 3 is a plan view and a partially cutaway perspective view of a flight control unit constituting the printing unit, showing a configuration of a toner charger constituting a printing unit of the image forming apparatus;

FIG. 4 is a diagram illustrating a configuration of a control unit of the image forming apparatus.

FIG. 5 is a diagram illustrating an image forming state in the image forming apparatus.

FIG. 6 shows another image forming state in the image forming apparatus,
FIG. 4 is a diagram illustrating an image reading state.

FIG. 7 is a diagram illustrating a configuration of an image forming apparatus according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a configuration of a printing unit of the image forming apparatus.

FIG. 9 is an enlarged cutaway perspective view showing a configuration of a flight control unit of an image forming apparatus according to another embodiment of the present invention.

FIG. 10 is a diagram illustrating a configuration of a control unit of the image forming apparatus.

[Description of Signs] 1-Printing section 2a, 2b-Flying control section 3-Toner charger 4-Paper feeding section 7-Control section 10-Image forming apparatus 11a, 11b-Counter electrode 22-Transmission hole 26-Control electrode 26a 26c-deflection electrode 31a, 31b-toner carrier 75-counter electrode power supply 76a-76c-deflection electrode power supply

Claims (5)

[Claims] A flying electric field is selectively formed in a plurality of passage holes facing each of a plurality of toner carriers arranged in parallel in a moving direction of a recording medium, and the flying electric field is applied to the toner carried by each toner carrier. In an image forming apparatus that forms an image by flying onto a recording medium via a formed passage hole, a control electrode divided into a plurality of ranges is arranged at each edge of the plurality of passage holes, and a plurality of toner carrying members are arranged. An image forming apparatus, comprising: voltage control means for controlling a voltage application state to each of a plurality of ranges of a control electrode according to a relative positional relationship of toner flying from each of the bodies on a recording medium. . 2. A first control electrode, which is divided into a plurality of ranges, is disposed at an edge of each of the plurality of passage holes on a recording medium side, and a second control electrode is disposed on an edge of the toner carrier side. The state of voltage application to each of the plurality of ranges of the first control electrode is controlled in accordance with the relative positional relationship of the toner flying from each of the plurality of toner carriers on the recording medium, and in accordance with the image signal. 2. The image forming apparatus according to claim 1, further comprising: a voltage control unit configured to control a voltage application state to the second control electrode. 3. The image according to claim 2, wherein said voltage control means applies a common voltage to each of a plurality of ranges of the first control electrode for a plurality of passage holes facing a single toner carrier. Forming equipment. 4. The voltage control means includes image reading means for reading an image formed on a recording medium via each of a plurality of toner carriers, and the voltage control means controls a voltage applied to a control electrode based on a reading result of the image reading means. The image forming apparatus according to claim 1, wherein the application state is controlled. 5. The image according to claim 4, wherein the voltage control means controls a voltage value to be applied to the control electrode or a voltage application timing based on a reading result of the pattern image for position detection. Forming equipment.