JP2000246950A - Method and apparatus for forming image, and recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an image quality by controlling an ink flow rate so that a total discharge volumetric flow rate of a plurality of inks becomes constant at all times. SOLUTION: A piezoelectric element is controlled by a control part 36 to make a total supply amount of a first and a second inks supplied from each ink channel constant at all times. The first and second inks thus controlled on flow rate are discharged as a continuous flow from an ink discharge port where a first and a second channels join and continuously applied to a print paper 12. Since a total flow rate of the plurality of inks discharged from the ink discharge port is maintained constant at all times, a transfer condition for ink liquids after mixed to an image-receiving body is made uniform and, the liquids can be transferred smoothly. For example, in an ink jet system, images of a high quality can be stably formed without affecting liquid drops for adjacent pixels by making a flow rate to be supplied newly to the ink discharge port agree with a volume of flying liquid drops.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generates a fluid having a predetermined density and / or a predetermined color by changing a mixing ratio of a plurality of inks based on an image signal, and guides the fluid to an image receiver. The present invention relates to an image forming method and apparatus for forming an image, and a recording head.

[0002]

2. Description of the Related Art In U.S. Pat. No. 4,109,282 (hereinafter referred to as Prior Art Document 1), a flap is provided in a flow path for guiding two liquids of a clear ink and a black ink to a base for image formation. There is disclosed a printing apparatus in which a valve called a valve is provided, the flow path of each ink is opened and closed by displacing the valve, and two liquids are mixed to a desired concentration and transferred onto a substrate. Thus, an image having the same gray scale information as the image information displayed on the TV screen can be printed out. Here, it is disclosed that a voltage is applied between a valve of a flap valve and an electrode provided on an opposite surface thereof, and the valve is displaced by mechanically deforming the valve itself by the electrostatic attraction. I have. The ink is sucked out by the capillary action between the fibers of the printing paper.

[0003] US Patent No. 4,614,953 (hereinafter referred to as Prior Art Document 2) discloses a printer head device in which inks and solvents of a plurality of different colors are introduced into a third chamber in desired amounts and mixed. Have been. Here, as means for weighing a desired amount of ink, a chamber,
It is disclosed that a diaphragm-shaped piezo effect element unit attached to the chamber is used, and a pressure pulse obtained by driving the piezo element is used.

Japanese Patent Application Laid-Open No. 5-201024 (hereinafter referred to as prior art document 3) discloses a liquid chamber filled with a carrier liquid, an ink jet driving means provided in the liquid chamber, a nozzle communicating with the liquid chamber, And a mixing unit for mixing the ink with the carrier liquid in the nozzle. It also discloses that an adjusting means for adjusting the mixing amount of the ink to a desired value is provided.

Japanese Patent Laid-Open No. 7-125259 (hereinafter referred to as Prior Art Document 4) similarly discloses first and second supply means for supplying inks having first and second densities, and a desired ink density. Thus, an ink jet recording head having a control means for controlling the supply amount of the second ink by the second supply means is disclosed.

Here, as a control means, a means using a micropump having a dedicated heating element and driven by the heat energy is disclosed. As the micropump, there is disclosed an example in which heat energy is generated by a heat generating element, and a piston-like valve or a cantilever-like valve is driven by pressure generated by nucleate boiling. It is also described herein that the use of the valve in combination with an actuator made of a shape memory alloy makes it possible to effectively control the amount of ink inflow particularly in a region where the amount of inflow is small.

Japanese Unexamined Patent Publication No. Hei 3-207664 (hereinafter referred to as Prior Art Document 5) has a structure similar to that of Prior Art Document 2, but does not use a third chamber for mixing a plurality of inks. It is shown.

Japanese Patent Application Laid-Open No. Hei 9-156131 (hereinafter referred to as prior art document 6) includes a plurality of printer heads for forming images of a plurality of colors based on image data, and a method of mixing ink and diluent at a predetermined mixing ratio. An ink jet printer is shown in which a diluted ink is mixed to form a diluted ink, and the diluted ink is ejected from a nozzle to form a recorded image on a recording medium. Here, when, for example, all-white image data in which the amount of mixed ink is small and does not reach a clear print density is input to the plurality of printer heads, the diluting liquid is supplied from at least one of the plurality of printer heads. There is disclosed an ink jet printer for discharging ink. As a result, a rapid change in gradation (tone jump) is prevented, and unnecessary consumption of the diluent is suppressed, and the drying property is improved.

Japanese Patent Application Laid-Open No. 10-264372 (hereinafter referred to as Prior Art Document 7) discloses an apparatus using a plurality of line heads in which ink discharge nozzles are arranged in a straight line. Here, the pixel density is increased by arranging the line heads so as to be shifted in the feed direction of the printing paper and by arranging the nozzle positions of the line heads relatively in the width direction of the printing paper. In addition, a single color ink is ejected from each nozzle, and a predetermined color is expressed on print paper by combining different color ink droplets by ejecting different color inks for each line head. Things.

[0010]

In the prior arts shown in the prior art documents 1 to 6, different inks are mixed in advance and then ejected. However, at least one of a plurality of inks to be mixed is ejected. This controls the supply amount of the seed ink. Therefore, the flow rate of the ink liquid having a desired density or color after being mixed, that is, the volume flow rate per unit time, fluctuates due to a change in density or color. If the volume flow rate of the mixed ink liquid per unit time (hereinafter, also simply referred to as flow rate) fluctuates due to the change in the mixing ratio depending on the density or color, the quality of the finally formed image is significantly reduced. I knew it would happen.

That is, in the above-described image forming technique using the conventional ink jet method, while the volume (discharge volume) of a droplet formed by one discharge operation is substantially constant, the discharge port (jet generation unit) The reason for this is that the liquid flow rate of the newly mixed ink that is successively supplied to ()) fluctuates.
For example, if the supply flow rate of the ink after mixing is large, the amount of liquid droplets that can be ejected in one ejection operation exceeds the amount that can be ejected, and the liquid remaining inside the ejection port mixes with the droplet of the next pixel. Become. If the supply flow rate of the ink after mixing is small, a part of the droplet for the next pixel is taken. For this reason, the image quality is adversely affected.

[0012] Further, the applicants are studying a system (hereinafter, referred to as a continuous coating system) in which the ink liquid is continuously transferred to an image receptor without being formed into droplets as an alternative to the ink jet system. However, it has been found that, even in this method, if the ink supply amount after mixing fluctuates as described above, various problems occur. For example, when the liquid supply amount of the mixed ink changes, the flow of the liquid may be disturbed.

That is, it is desirable that the liquid be transferred to the image receptor as a steady flow without any disturbance. However, if the flow is disturbed or eddy occurs, the image quality deteriorates. When the supply amount of the liquid fluctuates, coating films having different thicknesses are formed on the image receptor. However, depending on the structure of the liquid discharge port, such coating films having different thicknesses are stably formed. It is very difficult to do. Even if such a coating film can be formed, the surface of the image will have irregularities, and the image quality will also deteriorate.

In the prior art disclosed in the prior art document 7, a single color ink is ejected from one nozzle. Therefore, one pixel is divided into plural (three or four or more colors).
Of ink droplets. For this reason, there is a problem that it is difficult to increase the pixel density, and there is a limitation in improving the image quality.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an ink liquid having a desired concentration and / or color is obtained by mixing a plurality of inks having different densities and / or colors. It is a first object of the present invention to provide an image forming method capable of improving image quality when an image is formed and transferred to an image receptor to form an image. It is a second object of the present invention to provide an image forming apparatus directly used for carrying out this method. A third object is to provide a recording head used for manufacturing the image forming apparatus.

[0016]

According to the present invention, a first object is to discharge a plurality of inks from an ink discharge port while changing a mixing ratio of the plurality of inks based on an image signal. In an image forming method for forming an image by transferring an image to an image receiver relatively moving, an ink flow rate is controlled such that a total ejection volume flow rate of the plurality of inks is always constant. Formation method.

The image receiver can be used as a printing paper to form an image directly on the printing paper. However, a drum-shaped or belt-shaped intermediate image receptor is interposed between the discharge port and the image receptor, and the ink liquid supplied from the discharge port is placed on the intermediate image receptor, and then the ink liquid is received. It is good also as a method of transferring to a body. The ink ejection ports are preferably provided separately for each pixel arranged in the width direction of the image receptor (the direction orthogonal to the moving direction). However, when the density and / or color is changed only in the moving direction of the image receptor, The ink ejection port may be formed in a slit shape long in the width direction of the image receptor.

If at least one type of ink is an image non-forming ink, that is, an ink that becomes colorless and transparent after drying (hereinafter referred to as an image non-forming ink, a transparent ink), the density is changed by changing the mixing ratio of the image non-forming ink. It is preferable that the supply amount of the non-image forming ink is always added so as not to become zero. In this case, the image non-forming ink may contain an anti-fading agent such as an antioxidant or an ultraviolet absorber or other components to prevent the image from fading or impart other properties.

By transferring a plurality of inks for one pixel from the same common ink ejection port to the image receptor, it is possible to eliminate or minimize the density deviation and the color deviation of the image. However, a plurality of ink ejection ports may be formed separately for one pixel so as to be close to each other.
That is, the inks may be joined and mixed near each ejection port. By controlling the flow rates of the plurality of inks for each pixel, it is possible to form an image whose density and / or color changes in both the moving direction and the width direction of the image receptor.

The plurality of inks discharged from the ink discharge ports can be transferred to the image receptor as ink droplets by an ink jet system, ie, can be made to fly. However, the ink can be transferred to the image receptor as a continuous flow without being formed as droplets and applied. Possible (continuous application method). In the case of this continuous coating method, the liquid flow can be discharged as a continuous flow through a slit connecting the ink discharge ports provided for each pixel in the width direction, and can be transferred to the image receptor.

The flow rates of a plurality of inks (ink flow rates) can be controlled by various methods. For example, it is possible to change the cross-sectional area of each ink flow path by a piezo element while keeping the ink supply pressure to each ink flow path constant. In this case, the diaphragm valve facing the flow path is opened and closed by the piezo element. The piezo element can be driven at its own mechanical natural frequency (resonance frequency). By changing the number of pulses at this frequency, the driving time of the element is changed and the flow rate is controlled. The piezoelectric element can also continuously control the amount of distortion (opening of the diaphragm valve) by an analog signal. In this case, the flow rate is controlled by the voltage of the analog signal.

When the flow rates of a plurality of inks are all controlled by using the piezo elements, the total of the cross-sectional areas of the ink flow paths controlled by these piezo elements is always constant. For example, the total number of drive time pulses of each piezo element is made constant, or the total voltage of analog signals is made constant.

The flow rate supplied to each ink flow path may be controlled by changing the discharge rate of the ink supply pump. For example, the ink supply pump is driven by a pulse motor (stepping motor), and the ink flow rate can be controlled by the number of drive pulses of the pulse motor. The ink supply pump includes at least one check valve provided in the ink flow path, a cavity provided near the check valve, and a movable member that changes a capacity of the cavity. A device that discharges ink by changing the value can be used.

The check valve used here can be constituted by a geometrical shape in which the resistance between the ink flow direction and the opposite direction is small in the former case and large in the latter case. If there is no movable part, it can be manufactured using a method for manufacturing an integrated circuit or a printed wiring board, a method for manufacturing a micromachine, or the like. The ink supply pump may be driven by a pulse motor.

When a plurality of ink flow paths are provided with a pulse motor driven ink supply pump, the total number of drive pulses of the pulse motors for driving the respective ink supply pumps is always kept constant, so that the total amount of the ink liquid is increased. The flow rate can be controlled to be constant. The ink supply pump used here is preferably of a positive displacement type in which the discharge amount is proportional to the rotation amount of the motor.For example, a flexible tube closely attached to the inner surface of a circular case is fixed in a certain direction by an eccentric ring from the inner peripheral side. An intense pump, a vane pump, a gear pump, etc. are suitable.

The ink supply pump provided in each ink flow path can be formed by a piezo element and a check valve. In this case, the piezo element becomes a diaphragm valve driven at a mechanical resonance frequency unique to the element. Ink is controlled by controlling each piezo element so that the total number of pulses (the number of pulses within a fixed time or a unit time) of the driving frequency of each piezo element (the total number of pulses of each piezo element) is always constant. Can be made constant.

According to the present invention, the second object is to cause a plurality of inks to be ejected from an ink ejection port while changing a mixing ratio thereof based on an image signal, and to move relative to the ink ejection port. In an image forming apparatus that forms an image by transferring to an image receiver, an ink flow rate control unit that independently controls ink flow rates of the plurality of inks, and a mixing ratio of each ink corresponding to the image signal and A calculation unit for calculating the ink flow rate of each ink so that the total of the ink flow rates of the inks becomes a constant ejection volume flow rate; and a driver for driving the ink flow rate control unit based on the calculation result of the calculation unit. This is achieved by an image forming apparatus according to the present invention.

In order to control the ink flow rate, a diaphragm type flow rate control valve driven by, for example, a piezo element may be provided in the ink flow path. Instead of a diaphragm valve driven by a piezo element, a diaphragm valve using a heat-pressure effect or a diaphragm valve using electrostatic attraction or electrostatic repulsion may be used. In this case, it goes without saying that the ink supply pressure to the ink flow path is always kept constant. Instead of the flow control valve, the discharge amount of an ink supply pump that supplies ink to the ink flow path may be controlled. This pump is preferably a positive displacement pump driven by a pulse motor.

The ink flow control means includes a check valve provided in the ink flow path, a cavity provided near the check valve,
A movable member for changing the capacity of the cavity may be provided, and the ink may be ejected by changing the capacity of the cavity. Here, the check valve may be of a geometrical shape such that the ink flow resistance in the ink flow direction and the reverse direction is smaller in the former and larger in the latter. The movable member can be constituted by a diaphragm driven by a piezo element (or formed by the piezo element itself). The movable member is heat-
Diaphragm driven by pressure effect, electrostatic attraction or repulsion, magnetostriction effect, interfacial tension effect between ink and another fluid, or diaphragm driven by bubbles by electrolysis of fluid other than ink Can also be configured.

The ink discharge ports are arranged for each pixel arranged in the width direction of the image receptor, and these can be independently opposed to the image receptor. In this case, ink droplets can be transferred by an ink jet method. In this case, the coating may be performed by a continuous coating method instead of the ink jet method. When the continuous coating method is used, the fluid discharged from each ink discharge port can be guided to the image receptor through a slit that is long in the width direction of the image receptor. By passing through the slits as described above, the ink liquid flow can be further stabilized as a steady flow and guided to the image receptor.

In the case of the continuous coating method, the liquid discharged from the ink discharge port is transferred to the intermediate image receptor, and the ink liquid can be transferred from the intermediate image receptor to the image receptor. In this way, the transfer of the ink liquid ejected from the ink ejection port is smoothly performed by passing through the intermediate image receptor, and it is possible to prevent the occurrence of poor image quality due to uneven quality of the image receptor such as print paper. it can.

According to a third aspect of the present invention, there is provided a recording head for use in the image forming apparatus according to any one of claims 20 to 39, wherein the ink discharge ports are arranged in a direction relative to the relative movement direction of the image receptor. The recording head is characterized by being arranged along a straight line that is orthogonal or almost orthogonal.

The pixel density can be increased by allocating adjacent ink ejection ports to a plurality of parallel straight lines perpendicular or substantially perpendicular to the direction of relative movement of the image receptor.

[0034]

Since the total flow rate (volume flow rate per unit time) of the plurality of inks discharged from the ink discharge ports is always kept constant, the conditions for transferring the mixed ink liquid to the image receptor are uniform. A smooth transfer is performed. For example, according to the ink-jet method, a high-quality image can be formed stably without affecting the droplets for adjacent pixels by matching the flow rate newly supplied to the ink discharge ports to the volume of the flying droplets. can do.

According to the continuous coating method, the flow of the ink liquid flowing out of the ink discharge ports or slits does not fluctuate, and a high-quality image can be stably formed without generating disturbance or eddy in the flow. it can.

[0036]

FIG. 1 is a conceptual view of a continuous coating type image forming apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of an image forming section used here. In FIG. 1, reference numeral 10 denotes a platen, and reference numeral 12 denotes a print sheet wound around the platen 10 as an image receptor. This print paper 1
2 is sent in the direction of the arrow at a constant speed by rotating the platen 10 clockwise in the figure.

Reference numeral 14 denotes an undercoating section, which applies a transparent undercoating liquid to the print paper 12 in order to improve ink adhesion and improve image quality. Reference numeral 16 denotes an image forming unit serving as a recording head, which mixes the first ink and the second ink and guides the mixture to the print paper 12 to print the print paper 1.
2 to form an image. Reference numeral 18 denotes a heater for heating the print paper 12 on which an image is formed by the image forming unit 16 and drying the ink.

As shown in FIG. 2, the image forming section 16
, An ink flow path 20, a second ink flow path 22, and flow rate control valves 24 and 26 as ink flow rate control means for changing a flow path cross-sectional area of each of the flow paths 20 and 22.
The first ink is a non-image forming ink, that is, an ink that becomes colorless and transparent when dried, and contains a discoloration preventing agent such as an antioxidant or an ultraviolet absorber. The second ink is, for example, black ink.

The first and second inks are accommodated in ink tanks 28 and 30, respectively, and the first and second ink flow paths 20 and 22 are supplied from these ink tanks 28 and 30 by ink supply pumps 32 and 34, respectively. At a constant pressure. As the pumps 32 and 34 used here, for example, those having a pressure regulating valve on the ink ejection side and maintaining a constant ejection pressure are suitable.

The flow control valves 24, 26 have, for example, piezo elements 24A, 26A, and diaphragms 24B, 26B which advance and retreat into the ink flow paths 20, 22 due to distortion of the elements 24A, 26A. These piezo elements 24
A, 26A is a control unit 36 (FIG. 1), always controlled to a constant total feed amount S ₀ of the first and second ink supplied from the ink passage 20, 22.

The control unit 36 includes an arithmetic unit 38 and drivers 40 and 42 as shown in FIG. The calculation unit 38
The mixing ratio (S ₁ / S ₂ ) of the first and second inks is calculated based on the density signal (image signal). Here, the supply amounts S ₁ and S ₂ of the first and second inks are the sum (S ₁ +
S ₂ ) is determined to be a fixed amount S ₀ . Driver 40,
Reference numeral 42 drives the piezo elements 24A and 26A so that the supply amounts of the flow paths 20 and 22 become S ₁ and S ₂ .

For example, the piezo elements 24A and 26A are driven by pulses having a mechanical resonance frequency inherent to the elements, and the diaphragms 24B and 26B are driven by the number of pulses.
The number of times of opening and closing can be controlled, and as a result, the flow rates S ₁ and S ₂ can be controlled. In this case, if the flow path resistance of the ink flow paths 20, 22 and the ink supply pressure, the opening and closing conditions of the diaphragms 24B, 26B, and the like are uniform, the total number of drive pulses of the piezo elements 24A, 26A becomes constant. By controlling the total flow rate S ₀
= S ₁ + S ₂ can be maintained constant.

The first and second inks whose flow rates are controlled as described above are discharged as a continuous flow from the ink discharge port 44 where the first and second flow paths 20 and 22 merge. Print paper 1 facing and facing the exit 44
2 is continuously applied. In this case, the first and second inks are applied as a non-disturbed laminar flow without mixing with each other as shown in FIG. Here, the laminar flow includes a mixed flow only near the boundary between the first and second inks. The first and second inks may be mixed uniformly, but by forming a laminar flow in this way, the image surface formed on the print paper 12 is covered with any of the inks (here, the first ink). be able to. In addition, the image quality can be improved by using any of the inks (here, the second ink) as inks that are familiar with the undercoat layer of the print paper 12.

A large number of first and second ink flow paths 20, 22 and flow control valves 24, 26 are arranged in parallel in the width direction of the printing paper 12 (direction perpendicular to the moving direction), and may be provided for each pixel, for example. For example, the flow control valves 24, 2 corresponding to each pixel
6 can be formed by controlling the density signals (image signals). In this case, the ink ejection ports 44 can be independently opposed to the print paper 12 for each pixel. In addition, these ink discharge ports 44 can be opened in slits communicating with the print paper 12 in the width direction, and the ink liquid can be transferred from the slits to the print paper 12 and applied to the print paper 12.

[0045]

FIG. 3 is a perspective view showing an embodiment of such an image forming section (recording head) 16A, and FIG. 4 is an enlarged sectional view showing the applied state. This image forming unit 16A
Is provided with an ink discharge port 44 independent for each pixel and a slit 44A parallel to the ink discharge port 44 of each pixel, and ink liquid continuously discharged from each ink discharge port 44 has a laminar flow in the slit 44A. And are gathered in a belt shape, and are discharged onto the print paper 12.

The image forming section 16A has an undercoating section 14A.
Are integrated. The undercoat portion 14A is provided in the undercoat liquid flow path 1 parallel to the first and second ink flow paths 20 and 22.
4B and a slit 14C parallel to the slit 44A. Since the undercoat liquid L is colorless and transparent and is subjected to a pretreatment so that the ink is stably attached to the surface of the print paper 12, the undercoat liquid L is located upstream of the slit 44 </ b> A of the image forming unit 16 </ b> A with respect to the moving direction of the print paper 12. To position.

[0047] The undercoating liquid L has to prevent the disturbance or vortex is generated in the flow of the ink liquid I _NK during continuous coating of ink liquid I _NK, also functions to improve image quality. That is, as shown in FIG. 4, in the gap G formed between the image forming section 16A and the print paper 12, a part of the undercoat liquid L immediately after coming out of the slit 14C flows to the upstream side of the slit 14C and becomes liquid. A pool L1 is formed. The undercoat liquid L may be swirled in the liquid pool L1, but the undercoat liquid L is transparent and does not affect the coated surface.

[0048] Since the undercoating liquid L comes in front of the slit 44A becomes stable laminar flow of constant thickness with the movement of the print paper 12, the ink liquid I _NK ejected from the slit 44A has this stable subbed It is applied on the laminar flow of the liquid L. Disturbance or vortex is not generated in the flow of the for the ink liquid I _NK, it is capable of improving the image quality.

The third ink flow path 2 is provided in the image forming portion 16A.
3 may be provided. The third ink supplied from the third ink flow 23 is guided to an ink discharge port 44 via a flow control valve (not shown), and is transferred to the print paper 12 together with the first ink and the second ink. When the third ink flow path 23 is provided, yellow, magenta, and cyan color inks are supplied to the first, second, and third ink flow paths 20, 22, and 23, and the mixing ratio thereof is changed. By doing so, a color image can be formed.

[0050]

FIG. 5 is a sectional view showing an image forming section (recording head) 116 according to another embodiment. The image forming unit 116 is provided with the flow control valve 2 described with reference to FIGS.
4 and 26, the first and second ink flow paths 20,
The flow rate of the ink supplied to the ink supply pump 13
The control is carried out by changing the discharge amount of 2,134.

The pumps 132 and 134 are of a positive displacement type in which the discharge amount is proportional to the number of rotations. For example, the flexible tubes closely contacted with the inner surface of the circular case are pressed by the eccentric ring from the inner peripheral side. A stiff pump with a fixed tube orientation is suitable. The pumps 132 and 134 are driven by a pulse motor (stepping motor). The rotation amount of this motor can be controlled by the number of drive pulses, and as a result, the discharge amount of the pumps 132 and 134 can be controlled.

The control unit 136 is formed by an arithmetic unit 138 and drivers 140 and 142. The calculation unit 138 determines a mixing ratio of the first and second inks based on the density signal (image signal), and corresponds to each of the pumps 13 according to the mixing ratio.
The number of pulses n ₁ and n ₂ to be sent to 2,134 motors are obtained.
The drivers 140 and 142 send drive pulses of the pulse numbers n ₁ and n ₂ to the respective motors to drive the pumps 132 and 134, respectively. As a result, the first and second ink passages 20, 22
Are supplied with a predetermined amount of the first ink and the second ink, and these are turned into a fixed flow rate of ink liquid and transferred from the ink discharge port 44 to the print paper 12. In this case, n ₁ + n ₂ is set to a fixed number n ₀ so that the total amount of ejected ink is always constant.

[0053]

FIG. 6 is a sectional view showing an image forming unit (recording head) 216 according to another embodiment. In this embodiment, the ink supply pumps 232 and 234 for supplying the first and second inks are formed by cylinder pumps. Since the pumps 232 and 234 have the same structure, only one pump 232 will be described.

The cylinder pump includes a cylinder 232a,
It has a piston 232b, a feed screw 232c for moving the piston 232b forward and backward, and a pulse motor 232d for rotating the feed screw 232c. Motor 23
The piston 232b is moved to the cylinder 23 by the forward / reverse rotation of 2d.
2a moves forward and backward. As the piston 232b retreats, the first ink is sucked into the cylinder 232a from the ink tank 28 via the one-way valve 232e.
This ink is sent to the first ink flow path 20 via the one-way valve 232f with the approaching movement of the ink 32b.

Here, the amount of movement of the piston 232b is proportional to the amount of rotation of the motor 232d. Therefore, before forming one image, the piston 232b is sufficiently moved in the retreating direction to sufficiently suck the first ink into the cylinder 232a, and then the motor 232d is rotated by a rotation amount corresponding to the density signal. As a result, the piston 232b can be sent in the approach direction by a predetermined movement amount, and a predetermined amount of the first ink can be sent to the ink flow path 20. Motor 23 for pumps 232 and 234
2d (only one shown) can be driven by a control unit 136 similar to the embodiment shown in FIG.

[0056]

FIG. 7 is a sectional view showing an image forming section (recording head) 316 according to another embodiment. This embodiment is different from the ink supply pumps 132 and 13 shown in FIGS.
Instead of 4 and 232 and 234, ink supply pumps 332 and 334 using piezo elements are used.
The pumps 332 and 334 include piezo elements 332a and 3
34a and these piezo elements 332a and 334a
Cavities 332b, 334b, which are two wall surfaces, and inlets 332c, 334c, and outlet 332 which have a shape in which conductance (reciprocal of resistance) changes with respect to the cavities 332b, 334b depending on the direction of ink flow.
d and 334d. Here, the piezo element 332a,
It is desirable that the surface of the 334a that is in contact with the cavity portions 332b and 334b be subjected to some surface treatment or provided with a protective layer.

When the piezo elements 332a and 334a are driven and deformed, the cavities 332b and 334b
And the ink flows from the inlets 332c, 334c to the outlets 332d, 334d. Piezo element 3
32a and 334a are driven by the pulse voltage of the mechanical resonance frequency of each element. Therefore, each piezo element 332a, 33
By controlling the number of drive pulses 4a, the supply amounts of the first and second inks can be controlled. In this case, a control unit similar to the control unit 36 shown in FIG. 2 can be used.

[0058]

[Other Embodiments] FIGS. 8 to 12 show an image forming section (recording head) having an ink transfer means according to another embodiment.
8 is a piezo inkjet system, FIG. 9 is a thermal inkjet system, FIG. 10 is a continuous inkjet system, FIG. 11 is an electrostatic suction inkjet system, and FIG.
Reference numeral 2 denotes an ultrasonic ink jet system.

In these embodiments, flow control valves 24, 26 using piezo elements 24A, 26A similar to those in FIG.
The first and second inks controlled by
It is led to 4. In the ink transfer means A shown in FIG. 8, ink is ejected as droplets 402 using an ejection piezo element 400 provided near the ink ejection port 44, and the printing paper 1 is printed.
It leads to 2.

In the ink transfer means B of FIG. 9, the ink liquid is heated by a heater 404 provided near the ink discharge port 44 to generate a bubble 406 and discharge the ink droplet 402. In the method of FIG. 10, the electrodes 408 (408a, 408b) provided in front of the ink discharge ports 44 are provided.
In the meantime, the oscillator 410 applies a high voltage according to the image signal. As a result, the ink droplet 402 drawn from the ink discharge port 44 is provided with a charge according to the image signal. This is deflected by the deflection electrodes 409 (409a, 409b), and only unnecessary droplets 402a are guided to the printing paper 12 while unnecessary droplets 402b are removed by the baffle plate 412.

In the ink transfer means D shown in FIG. 11, the diameter of the ink ejection port 44 is reduced to a small diameter, and a high voltage corresponding to an image signal is applied between the ink ejection port 44 and the printing paper 12 by the oscillator 414. Ink ejection port 44 by high voltage
The ink droplet 402 is drawn out from the printer and sucked onto the print paper 12. In the ink transfer means E of FIG. 12, an ultrasonic transducer 416 is provided on the outer wall of the ink discharge port 44, and the ultrasonic wave emitted by the ultrasonic transducer 416 is focused on the ink liquid by the Fresnel lens 418 provided on the inner wall of the ink discharge port 44. This causes the ink liquid to vibrate and generate droplets 402.

In the embodiment described above with reference to FIGS.
Since one type of ink is a mixture of colorless and transparent inks, an image can be formed by changing the density. However, the present invention may simultaneously change the color and density by mixing two or more types of inks, for example, yellow, magenta, cyan, and black inks, or by mixing these with colorless and transparent inks. .
The image forming section 16 forms an image on an intermediate image receptor such as an intermediate drum instead of directly forming an image on an image receptor such as the print paper 12, and outputs the final image such as print paper from the intermediate image receptor. The image may be transferred to an image receptor.

[0063]

Another Embodiment FIG. 13 is a sectional view showing an image forming section (recording head) 516 according to another embodiment of the continuous coating method. This embodiment corresponds to the image forming unit 21 shown in FIG.
6, an ink supply pump 534 is used instead of the ink supply pump 234.

This ink supply pump 534 is configured similarly to the ink supply pump 334 shown in FIG. That is, the cavity 53 is formed in the second ink flow path 22.
4b and check valves 534c, 534d located before and after
And the volume of the cavity 534b is changed by a diaphragm driven by the piezo element 534a or a diaphragm integrated with the piezo element 534a.

[0065]

Another Embodiment FIG. 14 is a cross-sectional view showing an image forming section (recording head) 616 according to another embodiment of the present invention, which also employs a continuous coating method. This embodiment uses an ink supply pump 634 instead of the flow control valve 26 in the image forming section 16 shown in FIG.

The first ink is supplied to the first ink flow path 20 at a constant pressure by a pump (not shown), and the flow rate is controlled by a flow control valve 624 provided in the first ink flow path 20. In this flow control valve 624, the ink flow path area is controlled by the displacement of a diaphragm 624B driven by a piezo element 624A. The ink supply pump 634 provided in the second ink flow path 22 includes a piezo element 634a, a cavity 634b, and check valves 634c and 634c.
34d.

[0067]

Another Embodiment FIG. 15 is a cross-sectional view showing an image forming section (recording head) 716 according to another embodiment of the present invention, which also employs a continuous coating method. In this embodiment, an ink supply pump 734 is used instead of the ink supply pump 234 in the image forming section 216 shown in FIG.

The ink supply pump 734 is provided with a piezo element 734a facing the second ink flow path 22, and wedge-shaped projections 734b opposing each other are formed on the piezo element 734a and the inner wall of the ink flow path 22 facing the piezo element 734a. , 734
c is provided. Here projections 734b, 734c
Have slopes that spread toward each other in the ink flow direction. The protrusion 734b moves forward and backward in the ink flow path 22 by the vibration of the piezo element 734a. As a result, these projections 7
The ink sandwiched between the slopes 34b and 734c is pushed out toward the ink ejection port 44. Therefore, the piezo element 734
The ejection amount of the second ink is controlled by the frequency and amplitude of a.

[0069]

Other Embodiments FIGS. 16, 17, and 18 are perspective views showing different structures of a check valve, and FIG. 19 is a detailed explanatory view of the structure. Check valves 800, 802, 80 shown here
Reference numeral 4 denotes the ink supply pump 3 shown in FIGS.
34 (FIG. 7), 534 (FIG. 13), and 634 (FIG. 14). These check valves 800, 802, 8
Reference numeral 04 denotes a diaphragm having a geometric shape such that the resistance in the ink flow direction is greater than the resistance in the opposite direction. Therefore, it has no movable parts and can be easily manufactured by a micromachine manufacturing method.

The check valve 800 shown in FIG.
A has a slope 800b in which the area of the ink flow path increases almost continuously from the right side to the left side, and a plane 800c in which the area of the ink flow path rapidly increases in the opposite direction.

If there is a cavity whose volume varies near the check valve 800, the ink reciprocates through the check valve 800 due to the volume variation of the cavity. At this time, the resistance of the ink flow decreases in the leftward direction in FIG. 16 and increases in the opposite direction (rightward direction).
For this reason, due to the continuous volume change of the cavity portion, the ink flows in the direction of lower resistance, and functions as a check valve.

The check valve 802 shown in FIG.
A quadrangular pyramid-shaped diaphragm formed in a is used. FIG.
The check valve 804 shown in FIG. 8 uses a conical throttle formed on the substrate 804a. These check valves 802,
804 also functions similarly to the check valve 800 shown in FIG.

These check valves 800, 802, 804
Has a detailed structure shown in FIG. That is, in (A) of FIG. 19, the inclination θ of the slope 800b of the check valve 800, the pyramid and the conical face 80 of the check valves 802, 804
2b and 804b are inclined at the slope 800 of the substrate 800a.
It should be appropriately determined in relation to the length (hereinafter simply referred to as thickness) t of the component b with respect to the ink flow direction and the thickness t of 802 and 804a.

According to the experiment, in the range of 2 ° <θ <15 °, the flow resistance in the upward direction in FIG. 19 is smaller than the flow resistance in the downward direction, and the fluid flows upward. Also, 20 ° <θ
At <70 °, on the contrary, the upward flow resistance was larger than the downward flow resistance, indicating that the fluid flowed downward. In the case where the flow direction changes depending on the angle θ of the aperture, it is necessary to appropriately determine the angle θ.

FIG. 19B shows another structure of the check valve 800A. This check valve 800A has two conical surfaces 800
B and 800C are continuous with each other,
The angles that B and 800C make with the center line are θ ₁ and θ _{2, respectively.}
And the range of the angle θ ₂ is at least 800B
There than the angle theta ₁ formed by the center line to the large (θ _2> θ _1), and desirably at least 80 °, has been found to be approximately 90 ° is most preferable.

If the angle θ ₂ is significantly larger than 90 °, air bubbles tend to adhere to and collect on the conical surface 800C when flowing downward from above in FIG. 19B, which is not desirable. When the angle θ ₂ is less than 60 °, the function as a check valve is remarkably reduced. 800
It is more desirable that the connecting portion between B and 800C has an appropriate curved surface as shown by R in FIG.

[0077]

[Other Embodiments] FIGS. 20 and 21 are views showing examples of arrangement of recording heads in an image forming section. Image forming unit 8 shown in FIG.
Reference numeral 10 includes a large number of ink ejection ports 44 arranged on a straight line A in a range longer than the width of the image receptor. This image forming unit 8
Reference numeral 10 is arranged such that the angle わ る at which the arrangement straight line A of the ink discharge ports 44 intersects the transfer direction B of the printing paper 12 is 90 ° or almost 90 °. The image forming unit 810 shown in FIG. 21 is inclined so that the angle わ る at which the straight line A and the transport direction B intersect does not become 90 °.

According to FIG. 20, the image forming unit 810
Need to be provided at the same intervals as the pixels. According to the configuration shown in FIG. 21, the interval between the ink discharge ports 44 can be increased as compared with the configuration shown in FIG. Therefore, the image forming unit 810 can be easily manufactured.

[0079]

FIG. 22 is an enlarged view of an image forming unit 810.
FIG. 23 is an enlarged view showing another embodiment of the image forming unit. The image forming section 810 has a large number of ink discharge ports 44 arranged on the straight line A as described above. On the other hand, in the image forming unit 810A shown in FIG. 23, the adjacent ink discharge ports 44 are distributed on two parallel straight lines A1 and A2.

According to the image forming section 810A shown in FIG. 23, the ink discharge ports 44 adjacent to each other on the straight lines A1 and A2
Can be doubled as compared with that shown in FIG. Therefore, the production of the image forming unit 810A is facilitated. Note that the ink discharge ports 44 may be distributed to three or more straight lines instead of the two straight lines A1 and A2, and in this case, the production of the image forming unit is further facilitated. When the ink discharge ports 44 are allocated to the different straight lines A1 and A2 in this manner, the image forming section in which the ink discharge ports 44 are arranged on one straight line corresponds to the pixel pitch in the width direction of the print paper 12. It can be configured by shifting and overlapping a plurality of them.

[0081]

Other Embodiments In the above embodiment, the flow control valve (2
4, 26, 624) change the ink flow path area by driving a diaphragm valve by a piezo element, and are movable by an ink flow control means using a check valve, a cavity, and a movable member. The one in which the member is driven by the piezo element has been described. However, the flow control valve and the movable member may use a driving force based on a principle other than the piezo element. For example, those utilizing the heat-pressure effect, electrostatic quote or electrostatic repulsion can be used. Here, the heat-pressure effect uses a fluid (the ink itself may be used) whose flow resistance changes greatly with temperature,
The diaphragm is driven by using a pressure change of the fluid generated by changing the fluid temperature by a heater at one location in the fluid flow path.

For driving the diaphragm valve and the movable member, the magnetostrictive effect, the effect of the interfacial tension of a fluid different from a plurality of fluids used for image formation, or the heat of a fluid different from the fluid used for image formation is used. And / or the pressure of the bubbles generated by the electrolysis can be used. further,
Instead of changing the flow path resistance by heat by the heat-pressure effect, by changing other physical and chemical properties such as an electric field and a magnetic field, a fluid different from a plurality of fluids used for image formation is changed. By changing the flow path resistance, a change in the pressure of the fluid may be generated, and the change in the pressure may be used to drive the diaphragm or the movable member.

In the case of a diaphragm valve that opens and closes the ink flow path, a structure in which a valve plate that closes the ink flow path is held by a double-supported beam or a cantilever can be used. That is, the opening of the ink flow path is substantially perpendicularly opposed to the valve plate,
When the valve plate is configured to be pressed by an actuator such as a piezo element from a surface opposite to the opening of the ink flow path,
This valve plate is a double-supported beam or a cantilever.

In the embodiment shown in FIG. 2, the pump 3
2, 34 discharge ink at a constant pressure, and the flow control valve 24,
26 controls the ejection amount of each ink separately. In the embodiments shown in FIGS. 5 and 6, the pumps 132, 334 and 232, 234 each have a variable ink ejection amount. Further, the embodiment shown in FIG.
Thus, the ejection amount of each ink was made variable.

According to the present invention, both inks are supplied at a constant pressure and the discharge amount is controlled by a flow control valve (the embodiment of FIG. 2), and the discharge amount of each ink is made variable by a pump (FIG. 5). , 6, and 7), but it is also possible to supply a part of the ink at a constant pressure and make the ejection amount of the other ink variable. For example, ink that becomes colorless and transparent after drying is continuously supplied at a constant pressure without using a flow control valve, and another colored ink is supplied using a flow control valve (shown in FIG. 2) or a pump with a variable discharge amount (FIG. 5). , 6)
Alternatively, the discharge amount may be made variable by an ink supply pump (shown in FIG. 7).

In this case, since the area of the ink flow path through which all the inks collectively pass is always constant, the flow rate of one ink supplied at a constant pressure controls the discharge amount of the other ink. It changes naturally by changing the ink ejection amount. In addition, colorless and transparent ink supplied at a constant pressure without using a flow control valve can be uniformly guided from one ink pump to each ink ejection port by branching the ink flow path formed in the print head into an array. And the configuration of the recording head can be simplified.

The above embodiment has been described as forming an image. That is, the description has been made assuming that an image is drawn two-dimensionally on paper or film. However, the present invention can be used for manufacturing a mosaic filter used for an image display such as a liquid crystal color display, that is, a color filter in which yellow, magenta, and cyan color mosaics are repeatedly arranged. The present invention is also applicable to the manufacture of industrial products that form a spatially repeatable pattern.

[0088]

According to the first aspect of the present invention, as described above, the flow rate of the ink is controlled so that the total discharge volume flow rate of the plurality of inks is always constant. The transfer conditions of the ink liquid composed of ink are uniform, and smooth and high-precision transfer becomes possible. When at least one of the plurality of inks used here is non-image forming ink and the mixing ratio of the plurality of inks is controlled so as to always include the non-image forming ink, the mixing ratio of the non-image forming ink is changed. By doing so, the concentration can be changed. A plurality of inks can be used as yellow, magenta, and cyan inks to form a color image by changing the mixing ratio of these inks. When an image non-forming ink is used, the image non-forming ink may contain an anti-fading agent or the like to prevent the image from fading or to impart other special properties. ).

When a plurality of inks are ejected from a common ink ejection port, the image quality can be improved by eliminating or extremely minimizing the color misregistration and the density misregistration of the image. If the flow rates of the plurality of inks are controlled for each different pixel in the width direction (the direction orthogonal or substantially orthogonal to the moving direction) of the image receptor, an image whose density or color changes two-dimensionally is formed. (Claim 4).

In this case, the ink discharge ports corresponding to each pixel can be independently formed (claim 5). From the independently formed ink discharge ports, ink droplets can be received by an ink-jet method. It can be transferred to the body (claim 6). The inkjet method used here includes a piezo inkjet method, a thermal inkjet method, a continuous inkjet method,
An electrostatic suction ink jet system, an ultrasonic ink jet system, or the like can be used (claim 7).

The ink liquid discharged from the ink discharge port may be transferred to the image receptor as a continuous fluid flow, that is, an image may be formed by a continuous coating method (claim 8). In this case, the ink may be discharged as a continuous fluid flow from the ink discharge port provided for each pixel and applied to the image receptor, or may be discharged through a slit connecting each ink discharge port. In this case, any of the plurality of inks constituting the ink liquid is not mixed with each other, and any of the inks can always be applied to the image receptor side or the surface side as a non-disturbed laminar flow, thereby further improving the image quality. It can be improved (claim 9).

The ink flow rate can be controlled by changing the cross-sectional area of a plurality of ink flow paths (claim 10). To this end, a flow path control valve using a piezo element is provided in the ink flow path (claim 10). Item 11), each piezo element is controlled such that the total of the cross-sectional areas of the ink channels is always constant (Claim 12). The piezo element is driven at a mechanical resonance frequency unique to the element, and the ink flow rate may be controlled by the number of pulses at this frequency.

Instead of controlling the cross-sectional area of the ink flow path, the ink flow rate may be controlled by changing the discharge amount of the ink supply pump. The ink supply pump used here includes at least one check valve provided in the ink flow path, a cavity provided near the check valve, and a movable member that changes the capacity of the cavity. (Claim 1
5). The check valve used here may have a geometric shape in which the flow resistance in the ink flow direction is small and the flow resistance in the reverse direction is large, for example, a throttle (claim 16).

As the ink supply pump, a pump using a pulse motor capable of controlling the ejection amount by the number of pulses can be used. In this case, separate ink supply pumps for ejecting each ink are driven by a pulse motor, and control is performed so that the total number of drive pulses of a plurality of motors that drive the pumps for each ink is constant. Claim 1
8).

The ink supply pump may be formed by a piezo element and a check valve in place of the pulse motor.
9). In this case, the piezo element is driven at a mechanical resonance frequency specific to the element, and control is performed so that the total number of pulses of the driving frequency (for example, the number of pulses per unit time) for each piezo element is always constant. By doing so, the ink ejection volume flow rate can be controlled to be constant.

According to the twentieth aspect of the present invention, there is provided an image forming apparatus directly used for performing the above method. When the flow rate of each ink is controlled by a flow control valve provided in each ink flow path (claim 21), the flow control valve can be constituted by a diaphragm valve driven by a piezo element (claim). 22). The flow control valve is heat-
A diaphragm valve driven by a pressure effect (Claim 23) or a diaphragm valve driven by electrostatic attraction or electrostatic repulsion (Claim 2).
4).

The discharge amount of the ink supply pump may be controlled in place of the flow control valve. The ink supply pump can be composed of a check valve, a cavity provided near the check valve, and a movable member. Here, the check valve may be of a geometric shape in which the flow resistance in the ink flow direction is smaller than the flow resistance in the reverse direction (claim 27).

The movable member used here is a diaphragm driven by a piezo element (claim 28), a diaphragm driven by a heat-pressure effect (claim 29), a diaphragm driven by electrostatic attraction or electrostatic repulsion (claim 29). Claim 30), a diaphragm driven by the magnetostrictive effect (claim 31), a diaphragm driven by the interfacial tension effect of a fluid different from ink (claim 32), bubbles generated by electrolysis of a fluid different from ink. A driven diaphragm (claim 33) can be used.

When the ink supply pump is formed by a check valve and a piezo element provided in each ink flow path, control is performed so that the total number of pulses of the driving frequency of each piezo element is always constant. Item 34). The ink ejection port can be independently opposed to the image receptor for each pixel (Claim 35), and the ink liquid can be guided to the image receptor by an ink-jet type ink transfer means (Claim 39).

The ink discharge port is opposed to the image receptor in close proximity, and the ink liquid can be transferred from the ink discharge port to the image receptor as a continuous fluid flow.
Continuous application method). In this case, if each ink ejection port is opened in a common slit, and the ink liquid is ejected through this slit, a plurality of inks can be applied in a laminar flow without being mixed with each other. The image quality can be improved by imparting special properties to the ink exposed to the ink (claim 37). The image receptor includes not only a final image receptor such as printing paper but also an intermediate image receptor such as a drum.
8).

The recording head used in the image forming apparatus may have ink discharge ports arranged along a straight line perpendicular or substantially perpendicular to the direction of relative movement of the image receptor. However, if the straight line in which the ink ejection ports are arranged is inclined with respect to the direction of relative movement of the image receptor, the interval between the ink ejection ports can be increased.

The recording head sets adjacent ink ejection ports to:
The image may be distributed on a plurality of straight lines perpendicular or substantially perpendicular to the direction of relative movement of the image receptor.
1). In this case, the interval between the ink ejection ports arranged on each straight line is increased, so that the production of the coating head is further facilitated.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the image forming unit.

FIG. 3 is a perspective view illustrating an embodiment of an image forming unit.

FIG. 4 is an enlarged cross-sectional view showing a state of application.

FIG. 5 is a cross-sectional view illustrating an image forming unit according to another embodiment.

FIG. 6 is a cross-sectional view illustrating an image forming unit according to another embodiment.

FIG. 7 is a cross-sectional view illustrating an image forming unit according to another embodiment.

FIG. 8 is a diagram illustrating an image forming unit including an ink transfer unit according to another embodiment.

FIG. 9 is a diagram illustrating an image forming unit including an ink transfer unit according to another embodiment.

FIG. 10 is a diagram illustrating an image forming unit including an ink transfer unit according to another embodiment.

FIG. 11 is a diagram illustrating an image forming unit including an ink transfer unit according to another embodiment.

FIG. 12 is a diagram illustrating an image forming unit including an ink transfer unit according to another embodiment.

FIG. 13 is a cross-sectional view illustrating an image forming unit according to another embodiment.

FIG. 14 is a cross-sectional view illustrating an image forming unit according to another embodiment.

FIG. 15 is a cross-sectional view illustrating an image forming unit according to another embodiment.

FIG. 16 is a perspective view showing the structure of a check valve.

FIG. 17 is a perspective view showing the structure of a check valve.

FIG. 18 is a perspective view showing the structure of a check valve.

FIG. 19 is a detailed explanatory view of a check valve.

FIG. 20 is a diagram illustrating an example of the arrangement of image forming units.

FIG. 21 is a diagram illustrating an example of an arrangement of an image forming unit.

FIG. 22 is an enlarged view of an image forming unit.

FIG. 23 is an enlarged view showing another embodiment of the image forming unit.

[Explanation of symbols]

12 Print paper as image receptor 16, 16A, 116, 216, 316, 516, 616
6, 716 Image forming unit (recording head) 20 First ink flow path 22 Second ink flow path 24, 26, 624 Flow control valve 24A, 26A, 332a, 334a, 534a, 62
4a, 634a, 734a Piezo element 24B, 26B, 624b Diaphragm valve 28, 30 Ink tank 32, 34, 132, 134, 232, 234, 53
4, 634, 734 Ink supply pump 36 Control unit 38 Calculation unit 40, 42 Driver 44 Ink ejection port 334c, 334d, 534c, 534d, 634c,
634d, 800, 802, 804, 800A Check valve 810, 810A Image forming unit (recording head) A to E Ink transfer unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideo Ishizaka 798, Miyadai, Kaisei-cho, Ashigara-gun, Kanagawa Prefecture F-Film Co., Ltd. F-term (reference) 2C056 EA11 EC17 EC18 EC40 ED08 EE17 FA03 FA04 FA05 FA07 KB09 2C057 AF23 AG44 AH11 AM14 2C162 AE25 AE76

Claims (41)

[Claims] An image is formed by discharging a plurality of inks from an ink discharge port while changing a mixing ratio of the plurality of inks based on an image signal, and transferring the plurality of inks to an image receptor moving relative to the ink discharge port. In the image forming method for forming, the flow rate of the ink is controlled so that the total discharge volume flow rate of the plurality of inks is always constant. 2. The method according to claim 1, wherein at least one of the plurality of inks is a non-image-forming ink that does not substantially form an image after being dried. 2. The image forming method according to claim 1, wherein a mixing ratio is controlled. 3. The image forming method according to claim 1, wherein the plurality of inks are ejected from a common ink ejection port. 4. The image forming method according to claim 1, wherein the flow rates of the plurality of inks are controlled for different pixels in a direction orthogonal or substantially orthogonal to the moving direction of the image receptor. 5. The image forming method according to claim 1, wherein the plurality of inks whose flow rates are controlled for different pixels are respectively discharged from ink discharge ports provided corresponding to different pixels. 6. The image forming method according to claim 1, wherein the plurality of inks ejected from the ink ejection ports are transferred to an image receptor by an inkjet method. 7. The image forming method according to claim 6, wherein the inkjet method is any one of a piezo inkjet method, a thermal inkjet method, a continuous inkjet method, an electrostatic suction inkjet method, and an ultrasonic inkjet method. 8. The image forming method according to claim 1, wherein the plurality of inks ejected from the ink ejection ports are transferred to an image receptor as a continuous fluid flow to form an image. 9. A plurality of inks, the flow rates of which are controlled for different pixels, are transferred to the image receptor as continuous fluid flows through ink discharge ports provided for different pixels and further through slits connecting the ink discharge ports. An image forming method according to any one of claims 1 to 5, wherein an image is formed. 10. The image forming method according to claim 1, wherein the ink flow rate is controlled by changing a sectional area of the ink flow path. 11. The image forming method according to claim 9, wherein a sectional area of the ink flow path is controlled by a piezo element. 12. A piezo element is provided in each of ink channels for supplying a plurality of inks, and each piezo element is controlled such that the total cross-sectional area of the ink channels controlled by these piezo elements is always constant. The image forming method according to claim 11, wherein 13. The piezo element is driven at a mechanical resonance frequency unique to the element, and controls the ink flow rate by changing the number of pulses at this frequency.
1. An image forming method. 14. The image forming method according to claim 1, wherein the ink flow rate is controlled by changing a discharge amount of an ink supply pump. 15. An ink supply pump comprising: at least one check valve provided in an ink flow path; a cavity provided near the check valve; and a movable member for changing a capacity of the cavity. 15. The image forming method according to claim 14, further comprising: discharging ink by a change in the capacity of the cavity portion caused by the movable member. 16. The image forming method according to claim 15, wherein the check valve has a geometrical shape in which resistance to ink flow toward the ink discharge port is smaller than resistance in the opposite direction. 17. The image forming method according to claim 14, wherein the ink supply pump is driven by a pulse motor. 18. An ink supply pump driven by a pulse motor is provided in an ink flow path for supplying a plurality of inks, and each motor is controlled such that the total number of drive pulses of each motor is always constant. 18. The image forming method according to claim 17, wherein the method is performed. 19. An ink supply pump using a piezo element and a check valve is provided in each of ink paths for supplying a plurality of inks, and each piezo element is driven at a mechanical resonance frequency unique to the element. 15. The image forming method according to claim 14, wherein each piezo element is controlled such that the total number of pulses of this frequency is always constant. 20. A method for ejecting a plurality of inks from an ink ejection port while changing a mixing ratio of the plurality of inks based on an image signal, and transferring the plurality of inks to an image receptor moving relatively to the ink ejection port. In the image forming apparatus, an ink flow rate control unit that independently controls the ink flow rates of the plurality of inks, and a discharge in which a mixing ratio of each ink corresponding to the image signal and a total of the ink flow rates of each ink are constant. An image forming apparatus comprising: a calculation unit that calculates an ink flow rate of each ink so as to obtain a volume flow rate; and a driver that drives the ink flow rate control unit based on a calculation result of the calculation unit. 21. The image forming apparatus according to claim 20, wherein the ink flow control means is formed by a flow control valve provided in the ink flow path to change an area of the ink flow path. 22. The image forming apparatus according to claim 21, wherein the flow control valve is a diaphragm valve driven by a piezo element. 23. The image forming apparatus according to claim 21, wherein the flow control valve is a diaphragm valve driven by a heat-pressure effect. 24. The flow control valve is a diaphragm valve driven by electrostatic attraction or electrostatic repulsion.
Image forming apparatus. 25. The image forming apparatus according to claim 20, wherein the ink flow control means is formed by a pulse motor driven ink supply pump provided in the ink flow path. 26. The ink flow control means includes a check valve provided in the ink flow path, a cavity provided near the check valve, and a movable member for changing a capacity of the cavity. 21. The image forming apparatus according to claim 20, wherein the ink is ejected by changing the capacity of the cavity by the movable member. 27. The image forming apparatus according to claim 26, wherein the check valve has a geometric shape in which resistance to ink flow toward the ink discharge port is smaller than resistance in the opposite direction. 28. The image forming apparatus according to claim 26, wherein the movable member is a diaphragm driven by a piezo element. 29. The image forming apparatus according to claim 26, wherein the movable member is a diaphragm driven by a heat-pressure effect. 30. The image forming apparatus according to claim 26, wherein the movable member is a diaphragm driven by electrostatic attraction or electrostatic repulsion. 31. The image forming apparatus according to claim 26, wherein the movable member is a diaphragm driven by a magnetostrictive effect. 32. The image forming apparatus according to claim 26, wherein the movable member is a diaphragm driven by an interfacial tension effect of a fluid different from a plurality of inks used for image formation. 33. The image forming apparatus according to claim 26, wherein the movable member is a diaphragm driven by bubbles generated by electrolysis of a fluid different from a plurality of inks used for image formation. 34. An ink flow control means is provided in each ink flow path for respectively supplying a plurality of inks, and each piezo element is driven at a mechanical resonance frequency unique to the element, while the driving frequency of each piezo element is 29. Each piezo element is controlled such that the total number of pulses is constant at all times.
Image forming apparatus. 35. An ink discharge port is provided for each pixel in a direction perpendicular or substantially perpendicular to the moving direction of the image receptor, and these ink discharge ports independently face the image receptor. 35. The image forming apparatus according to any one of -34. 36. The ink discharge port, wherein the plurality of inks are discharged from the ink discharge port as a continuous fluid flow and transferred to the image receptor.
35. The image forming apparatus according to any one of -34. 37. A plurality of ink ejection ports provided for each pixel are opened in slits which are close to and opposed to the image receptor, and a fluid ejected from each ink ejection port is a continuous fluid flow from the slit in a strip shape. The image forming apparatus according to any one of claims 20 to 34, wherein the image forming apparatus is transferred to an image receiving member. 38. The image forming apparatus according to claim 36, further comprising an intermediate receptor that continuously receives fluid discharged from the ink discharge port and transfers the fluid to the image receptor. 39. The image forming apparatus according to claim 20, further comprising an ink transfer unit for guiding a fluid discharged from an ink discharge port to an image receptor by an ink jet method. 40. A recording head used in the image forming apparatus according to claim 20, wherein the ink ejection port is
A recording head, which is arranged along a straight line perpendicular or substantially perpendicular to the direction of relative movement of an image receptor. 41. A recording head used in the image forming apparatus according to any one of claims 20 to 39, wherein adjacent ink ejection ports are parallel to each other orthogonally or substantially orthogonally to a relative movement direction of an image receptor. A recording head characterized by being distributed on a plurality of straight lines.