JPH11198444A - Print head and image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a print head for forming a high quality image at low energy and an image recorder employing it. SOLUTION: A print head 19 comprises a tubular roll 1, a tank 2 for transparent volume, and an ink head 6 for imparting a coloring ink to a transparent medium pushed out to the surface of the tubular roll 1. A control board 4 provides image information through a mechatro control board 5 to the print head 19 and through a memory board 3 to the coloring ink head 6. Based on the image information, an image of colored transparent medium is formed on the surface of the tubular roll 1. That image is transferred to a recording sheet 9 using an image transfer roll 7. A solidifying liquid imparting head 8 disposed on the recording sheet discharging side imparts solidifying liquid to the transferred image thus fixing the image onto the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head used for an image recording apparatus such as a printer, and more particularly to a print head suitable for recording high-quality images and an image recording apparatus using the same.

[0002]

2. Description of the Related Art An image recording apparatus such as an ink-jet printer or the like is configured to form small droplets of ink by applying energy and deposit the droplets on a recording support such as paper. ing. For example, a method of scanning and printing on the recording support with one or several nozzles for each color, such as a scan type, and a method of printing using multiple nozzles arranged in an array, such as an array type There is. The ink ejection mechanism used in these methods is to apply an external force such as pulse pressure, electrostatic force, or electroosmotic force to the ink in the cavity to eject ink particles from the orifice. The pulse pressure is
It is created by the pressure of bubbles due to deformation of the piezo transducer or heating and boiling of the ink.

[0003] The ink jet system utilizing this kind of pressure can use only ink having a viscosity of about 1 to 3 mPa · s. With ink having such a viscosity, when the ink lands on the paper, the ink bleeds along the fibers of the paper. Further, the printed dot shape becomes larger or non-uniform compared to the diameter of the discharge nozzle. Further, in the case of the color ink jet, there is a problem that when adjacent dots come into contact with each other, bleeding of the ink develops into a mixed color.

[0004] In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. Hei 2-307753 discloses a technique of supplying a bleeding preventive agent to the back surface of recording paper before ink is printed. Also, JP-A-64-63185 discloses that
There has been disclosed a technique in which a solution for insolubilizing ink is landed on a recording support from a nozzle, and the ink is discharged thereon to prevent bleeding.

[0005] However, both methods are insufficient in the effect of preventing bleeding. For example, when a liquid for insolubilizing the ink is applied on the recording support, the insolubilizing liquid causes paper wrinkles on the paper itself.

As a solution to these problems, use of a thickened ink has been proposed. One of the typical methods is a method of converting ink into a special hot melt type. However, in this method, the viscosity of the ink that can be ejected is limited to about 10 mPa · s, and to increase the viscosity further, heat energy for instantaneously melting the ink is required. Then, it goes against the direction of low energy.

[0007] In addition, there has been proposed an ink jet apparatus which can use high viscosity ink. For example, Japanese Unexamined Patent Publication
No. 9384 discloses a technique in which a large number of curved individual ink paths are formed in an array at regular intervals inside a polarizer made of a piezoelectric material of a head. This method is
A voltage is applied to the electrode to cause a large displacement in the array direction, and the ink in the increased ink chamber is ejected by the recoil of the displaced ink wall.

Japanese Patent Application Laid-Open No. 4-257485 discloses that
There has been disclosed a technique in which high-viscosity ink is printed by attaching ink instead of discharging. This method uses ink exhibiting the electrorheological effect, provides electrodes near the ink discharge ports that are in direct contact with the recording medium, and controls the amount of ink discharge by applying an electric field in accordance with the image signal to these electrodes. I do. Usable ink viscosity is 50-1000
mPa · s.

[0009]

However, in the method of forming the individual ink paths in an array, even if the displacement is increased by bending the piezoelectric material in a curved shape, when the viscosity is 10 mPa · s or more, the generated displacement becomes large. Vibration from the ink is absorbed by the ink itself. This makes it difficult to eject ink. Alternatively, the landing positions of the liquid droplets vary with the flight, and the problem remains in the positional accuracy of the recording dots.

[0010] The method of adhering ink is based on the premise that a special material called electrorheological ink is used. In the case of such a high-viscosity ink, in the operation after the ink is attached, the stringing state of the ink occurs due to the shearing force of only the paper. Further, since the discharge opening is in direct contact with the paper, there is a problem that the discharged ink is rubbed at the tip of the nozzle.

Further, since the flow path of the electrorheological ink is controlled, when the power supply of the apparatus main body is cut off, the outflow amount of the ink cannot be controlled, and there is a possibility that the ink leaks from the discharge port.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a print head capable of forming a high quality image with low energy and an image recording apparatus using the print head. It is in.

[0013]

An object of the present invention is to provide a cylindrical roll having a plurality of openings on its surface, a tank for storing a transparent medium to be supplied to the openings, and a method for opening the transparent medium in accordance with image information. The present invention is achieved by a print head including a medium extruding element extruded into a portion, and a device for applying a coloring ink to a transparent medium extruded from the medium extruding element.

Here, the openings on the surface of the cylindrical roll are arranged at equal intervals. The medium pushing element is configured using an electric vibration conversion element. This electric vibration conversion element
The operation is stopped until the transparent medium in the opening is transferred onto the recording support. Further, the device for applying the coloring ink has a single color or two or more color ink storage units,
It is adapted to color image formation.

[0015] The image recording apparatus according to the present invention is a print head configured to apply coloring ink to a transparent medium extruded from a plurality of openings provided on the surface of a cylindrical roll based on image information. And an image support driving device for transferring the colored transparent medium to the image support, and a solidifying liquid applying device for applying a solidifying liquid to the transparent medium transferred on the image support.

Here, the transparent medium contains a polysaccharide polymer and water, and the solidified liquid contains a metal salt and water. This polysaccharide polymer has a molecular weight of 10,000 or more and 1,000,000.
Algin below 0, or alginic acid or a monovalent metal salt of alginic acid or carrageenan can be used. As the solidification liquid, an aqueous solution of a metal salt having a pH of 6 to 9 is preferably used.

In the image recording method according to the present invention, a step of extruding a transparent medium from a plurality of openings provided on the surface of a cylindrical roll based on image information, and applying a coloring ink to the extruded transparent medium. A step of transferring the colored transparent medium to the image support, and a step of applying a solidifying liquid to the image area on the transferred image support.

Thus, it is possible to obtain a print head capable of forming a high-quality image with low energy and an image recording apparatus using the print head.

[0019]

FIG. 1 is a diagram showing an embodiment of an image recording apparatus using a print head according to the present invention. In this embodiment, the print head 19 includes a cylindrical roll 1 and a transparent medium tank 2 provided therein, as shown in FIG.
A black BK for applying a coloring ink to a transparent medium extruded from a plurality of openings formed on the surface of the cylindrical roll 1;
And a color ink head 6 for each of cyan C, magenta M and yellow Y. The control board 4 gives image information to the print head 19 via the mechatronic control board 5 and to the coloring ink head 6 via the memory board 3, respectively.

On the other hand, the image transfer roll 7 is provided to face the print head 19. The recording paper 9 is supplied to the image transfer roll 7. The recording paper 9 is a paper transport roll 10
The paper is supplied using a paper transport belt 11 driven by the printer. A solidifying liquid applying head 8 is provided on the recording paper discharge side. The solidified liquid lands on the paper 9 by the airflow from the airflow generating electromagnetic valve 8-1.

The image recording apparatus thus configured operates as follows. First, based on the image information from the control board 4, the coloring ink head 6 applies coloring ink to the transparent medium extruded from the plurality of openings formed on the surface of the cylindrical roll 1. The colored transparent medium is transferred to the recording paper 9 by the image transfer roll 7.
The image is formed by being transferred to the surface. The solidification liquid is applied from the solidification liquid application head 8 to the image formed on the paper, so that the image is fixed on the paper.

FIG. 2 is a diagram showing steps from extrusion of the transparent medium to fixing of the image. FIG. 1A shows a state of an image section 21 in which a transparent medium is extruded from a plurality of openings 20 formed on the surface of the cylindrical roll 1 based on image information. The hatched part in the figure is the image part 21, and the other part is the non-image part 22. As shown in FIG. 2B, the image portion 21 includes a coloring ink head 6.
, And the image portion 21 is colored as shown in FIG. Then, the image portion 21 is transferred to the recording paper 9 by rotating the cylindrical roll 1 as shown in FIG. The solidified liquid is applied to the transferred image portion 21 from the solidified liquid applying head 8 as shown in FIG. As a result, FIG.
The image portion 21 is fixed on the paper 9 as shown in FIG.

FIG. 3A is a view showing the internal configuration of the cylindrical roll 1, and FIG. 3B is a partially enlarged view thereof. As shown in FIG. 2A, the transparent medium stored in the tank 2 is supplied to the medium pushing element 13 through the transparent medium supply orifice 14. Each medium pushing element 13 is connected to an image signal transmission line 15 and pushes a transparent medium onto the surface of the cylindrical roll 1 based on image information.

FIG. 3B shows the medium pushing element 13.
As shown in (1), an electric vibration conversion element is used. This element includes a piezoelectric element 17 and a diaphragm 18, and is configured such that when image information is received via the image signal transmission line 15, the piezoelectric element 17 pushes the diaphragm 18 in the direction of the arrow based on the image information. At this time, the diaphragm 18 can move only in the direction of the arrow because both ends are fixed to the resin wall 16. The vibrating slope 18 is configured such that a slight displacement causes the transparent medium in the medium pushing element 13 to be pushed out of the opening. The medium pushing element 13 includes a piezoelectric element pulse power supply 23 and a vibrator power supply 24 as drive power supplies.

FIGS. 4A to 4H are views showing a series of operations from image formation to image transfer by the medium push-out element 13. FIG. First, as shown in FIG. 2A, the piezoelectric element 17 deforms the vibration plate 18 based on image information, thereby pushing out the transparent medium from the opening. Then, as shown in FIG. 3B, the movement of the diaphragm 18 is stopped in a state where the transparent medium is pushed out from the opening. Diaphragm 18
Is controlled so that the next operation is not performed during one rotation of the roll. The rotation cycle of the roll is configured to link with the printing cycle. As shown in FIG. 4C, the coloring ink is applied to the extruded transparent medium by the coloring ink head 6 while the transparent medium is raised, and the transparent medium is colored. Next, the colored transparent medium comes into contact with the paper 9 as shown in FIG. At this time, unnecessary moisture in the colored transparent medium is absorbed by the paper 9. Since the colored transparent medium has a stronger adhesive force with the sheet 9 as shown in FIG. FIG.
When the diaphragm 18 returns to its original state as shown in FIG. 7, the transparent medium rapidly moves in the original direction due to capillary action. In this state, the amount of the transparent medium remains reduced by the transfer of the transparent medium to the sheet as shown in FIG. Then, as shown in FIG. 2H, the transparent medium is supplied from the tank 2 to the medium pushing element 13 through the transparent medium supply orifice 14.

Here, on the surface of the cylindrical roll 1, a plurality of openings 20 are formed by electroforming or laser or the like using a roll formed from a metal plate of stainless steel, nickel or the like. In the medium push-out element 13, the piezoelectric element 17 is formed of a dielectric material such as barium titanate or PZT, and the diaphragm 18 is formed of a metal film such as stainless steel, nickel or titanium, or a highly elastic resin film.

The print head in this embodiment is compatible with full-color printing, and has a transparent medium discharge density of 360 dpi (7 dpi).
0.58 μm), the number of transparent medium discharge ports is 3008 nozzles (printing width: 212 mm),
m are also arranged at the same density in the circumferential direction. Therefore,
When the roll makes one rotation while forming an image on the recording paper, an image for one vertical A4 size sheet is formed.
In addition, the droplet diameter of the colored ink is 35 μm. The driving voltage of the piezoelectric element 17 is, for example, 20 V, and the driving frequency is given in a pulse shape so as to link the rotation of the roll. The amount of one ink ejection is adjusted to, for example, 0.05 μg.

The recording medium may be any medium such as paper, cloth, plastic, leather, metal plate, etc., as long as ink can be applied by the head of the present invention.

FIG. 5 is a graph showing the relationship between the applied pressure and the ink viscosity when ink (liquid) is extruded from the roll surface opening according to the present invention, in comparison with the related art. From this figure, it can be seen that the method of the present invention by extrusion from the meniscus can apply high-viscosity ink to the paper at a low pressure. Therefore, the print head according to the present invention is suitable for low energy printing.

Further, since the present invention is configured to apply the coloring ink to the transparent medium, the transparent medium can be easily changed to a desired color by changing the color of the applied ink. In addition, since the transparent medium extrusion openings are provided at equal intervals, if there are openings for pixels corresponding to the image density, a state in which a desired color image corresponding to the outer peripheral length of the roll can be formed at a time is provided. . In the case of full-color printing, it is possible to cope with the case where the number of liquid ejection heads is one and the coloring ink heads are four colors of yellow, magenta, cyan and black. Since only one extrusion head is required, the configuration of the apparatus is simplified and the size can be reduced. Further, reliability can be improved.

As described above, the electric vibration converting element is used as the medium pushing element. This element transfers the transparent medium onto the recording support in a convex state without flying from the opening. Then, in this state, the device operation is temporarily stopped. As a result, the transparent medium swells only on a portion corresponding to the image information on the peripheral surface of the roll, and a state where the transparent medium does not swell on the portion without the image information is formed. Coloring ink is landed on the raised portion of the transparent medium. By making the diameter of the extrusion opening of the transparent medium larger than, for example, at least twice the diameter of the droplet of the coloring ink, even if the trajectory of the coloring ink is displaced, a part of the trajectory will contact the transparent medium and the dyeing will be performed reliably. Will be The colored transparent medium is transferred to the paper by contact without flying, so even with a viscous liquid,
Transfer can be reliably performed without causing stringing due to the adhesive force to the paper and the shearing force due to the rotation of the liquid pushing head. Further, since the transparent medium is not caused to fly, the displacement of the recording dots is reduced as compared with the conventional ink jet system.

Further, since the medium pushing element stops the operation of pressing the ink until it comes into contact with the paper, the response frequency of the vibrating element only needs to be within the rotation time of one rotation of the roll, and is lower than that of the conventional ink jet system. The response frequency can be applied.

The transparent medium used in the present invention contains a polysaccharide polymer and water, and the solidified liquid contains a metal salt and water.
Here, the polysaccharide polymer has a molecular weight of 10,000 or more and 1.0 or more.
Algin less than or equal to 000, or alginic acid or a monovalent metal salt of alginic acid or carrageenan is used. An aqueous solution of a metal salt having a pH of 6 to 9 is used as the solidification liquid. When the transparent medium comes into contact with the solidification liquid, the metal salt dissolved in water diffuses into the polysaccharide polymer dissolved in water, and instantaneously retains and solidifies water as a solvent.

Alginic acid is a natural polysaccharide polymer extracted from brown algae, and is contained in seaweed and kelp. Alginic acid is used as a sodium salt in foods, pharmaceuticals,
In various fields such as cosmetics, it is widely used as a water-soluble thickener, as a jelly by adding calcium, or as an enzyme-immobilized bead. The structure of sodium alginate is a sodium salt composed of a polymer of β-1,4-D-mannuronic acid (M) and α-1,4-L-guluronic acid (G). Sodium alginate forms a chelate with a polyvalent metal salt such as calcium and takes in moisture to form a gel. When these are linked to form a polymer, the gel forming ability becomes remarkable depending on the ratio of GM, MM, and GG. In the GG cluster region, molecules are bent, and calcium ions, one of the solidifying liquids, enter into the GG cluster region to form an egg-box type structure, thereby forming a strong polymer. The gel formed has an increased film-forming ability with an increase in the molecular weight of alginic acid, and a film that is not dissolved in water or oil is formed. The molecular weight is 10,000 or more, preferably 5
More than 000 is suitable.

The other carrageenan is a seaweed polysaccharide extracted from red algae. The chemical structure of carrageenan is a linear polymer having a molecular weight of hundreds of thousands to millions, and is composed of D-galactose, 3,6-anhydro-D-galactose, and a sulfate group. Depending on the content of sulfate groups, κ
Type, λ type, and τ type. The kappa type is preferable in that the mechanical strength of the generated gel is strong. This instantaneously gels in the presence of a monovalent or polyvalent cation ion such as potassium or cesium which is a solidified liquid. Carrageenan has a helical structure in its molecular chain. The helical structure aggregates via the cation ion to form a gel.

Accordingly, it is possible to prevent the paper from waving or curling due to water penetrating into the paper fibers. Also,
The aqueous solution of the viscous polysaccharide polymer does not penetrate along the paper fibers and cause feathering,
In addition, no color mixing or bleeding due to the coupling of the droplets occurs. Furthermore, the gelled polysaccharide polymer has effects such as high water resistance and heat resistance, and the image constituent is stable on paper.

Next, the fixing mechanism of the transparent medium and the image used in the recording apparatus will be described. The ink used was Special Black Bayer A-SF (Bayer
1.5 wt% and 0.1 wt% of sodium sulfonic acid formalin condensate were dispersed in ion-exchanged water. As the transparent medium, 5 wt% of sodium alginate (manufactured by Wako Pure Chemical Industries, Ltd.) having a molecular weight of 18,000 was adjusted. This is a viscous liquid. As the solidification solution, a 10 wt% aqueous solution of calcium chloride (pH 7.8) was prepared.

[0038] Ink is applied to the transparent medium and brought into contact with the recording medium, and a solidifying liquid is applied on the image. As a result, the image gels instantaneously and firmly adheres to the recording support. Accordingly, an image without recording dot bleeding can be obtained at high speed without requiring energy for fixing. In addition, monochrome and full color printing can be easily performed by replacing the ink cartridge. Further, since the print dots do not fly, the accuracy of the print position on the image support is also improved.

Example 1 In order to confirm the printing performance of the image recording apparatus according to the present invention, a print test was performed under the following conditions. The image recording apparatus used in this experiment has the same configuration as that of FIG. 1, and the liquid pushing head has the same configuration as that of FIG. Black ink was used.

・ Liquid push-out head Material: Stainless steel Outer diameter 12φmm Width 212mm Opening 70.5μm ・ Ink ejection element Vibration plate: Nickel plate Functional element Piezoelectric element: PZT Ink chamber wall material: Urethane resin Ink ejection diameter: 35μm ・ Process Speed 100mm / sec ・ Recording ink material Special black BayerA-SF1.5wt% Other recording inks use colored pigment-containing material Dispersed sodium thorium sulfonate 5wt% ・ Transparent medium Sodium alginate・ Solid solution 10% aqueous solution of calcium chloride (pH 7.8) is used ・ Solid solution applying device 3000 full-length nozzles with 100 μm opening diameter ・ Solid solution applying device Air flow generation Pump (70 l / min)

When a print test was conducted under the above conditions, a high-quality image free from image bleeding could be obtained at a high speed. In addition, there has been no occurrence of a conventional problem of recording dot displacement.

(Embodiment 2) In Embodiment 2, the image recording apparatus of Embodiment 1 is used and only the ink is changed. Specifically, the special black Ba used in Example 1 was used.
The cyan, magenta, and yellow inks were prepared by replacing yellowA-SF with Acid Blue 9, Direct Red 227, and Direct Yellow 87, respectively.

In this embodiment, the paper is wound around the image support roll, the meniscus of the transparent medium colored with each color ink is sequentially transferred onto the paper, and after the transfer of the four colors is completed, the air flow from the solidifying liquid applying device is performed. The mist-like solidified liquid was sprayed onto the image area on the paper to obtain a recorded matter on which a color image constituent was fixed. The recorded matter was a clear color image without color mixture, no waviness on the paper, and no variation in the positions of the printing dots.

As described above, in the image recording apparatus using the print head according to the present invention, the image corresponding to the outer circumference of the roll is transferred to the recording support at the same time, so that high-speed printing is possible. In addition, full color printing becomes possible just by changing the cartridge with one extrusion head,
The device can be downsized. Also,
Since the colored transparent medium is transferred by contact without flying, it is not necessary to precisely control the behavior at the time of flying, and there is no problem of dot displacement during recording. Further, the transparent medium can be fixed without using heat energy and the like, and occurrence of bleeding can be suppressed. Therefore,
It has many advantages, such as high-speed printing with low energy.

[0045]

According to the present invention, a print head capable of forming a high quality image with low energy and an image recording apparatus using the same can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an image recording apparatus using a print head of the present invention.

FIGS. 2A to 2G are diagrams illustrating steps from extrusion of a transparent medium to fixing of an image.

FIG. 3A is a diagram showing an internal configuration of a cylindrical roll;
(B) is a partially enlarged view thereof.

FIGS. 4A to 4H are views showing a series of operations from image formation to image transfer by a transparent medium pushing element.

FIG. 5 is a graph showing a relationship between ink viscosity and ink application pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical roll 2 Transparent medium tank 3 Memory board 4 Control board 5 Mechatronic control board 6 Coloring ink head 7 Image transfer roll 8 Solidifying liquid application head 8-1 Solenoid valve for air flow generation 9 Recording paper 10 Paper transport roll 11 Paper Conveyor belt

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B41J 29/00 H

Claims (10)

[Claims] 1. A cylindrical roll having a plurality of openings on a surface thereof, a tank for storing a transparent medium to be supplied to the openings, a medium pushing element for extruding the transparent medium into the openings according to image information, A device for applying a coloring ink to the transparent medium extruded from the medium pushing element. 2. The print head according to claim 1, wherein the openings on the surface of the cylindrical roll are arranged at equal intervals. 3. The print head according to claim 1, wherein the medium pushing element is configured using an electric vibration conversion element. 4. The print head according to claim 3, wherein the operation of the electric vibration conversion element is stopped until the transparent medium in the opening is transferred onto the recording support. 5. The print head according to claim 1, wherein the device for applying the coloring ink has a single color or two or more color ink storage units. 6. A print head configured to apply coloring ink to a transparent medium extruded from a plurality of openings provided on a surface of a cylindrical roll based on image information.
An image recording apparatus comprising: an image support driving device for transferring the colored transparent medium to an image support; and a solidifying liquid applying device for applying a solidifying liquid to the transparent medium transferred on the image support. apparatus. 7. The image recording apparatus according to claim 6, wherein the transparent medium contains a polysaccharide polymer and water, and the solidified liquid contains a metal salt and water. 8. The polysaccharide polymer has a molecular weight of 10,0.
7. The image recording apparatus according to claim 6, wherein the recording medium is algin having an amount of from 00 to 1,000,000, alginic acid, a monovalent metal salt of alginic acid, or carrageenan. 9. The image recording apparatus according to claim 6, wherein the solidification liquid is a metal salt aqueous solution having a pH of 6 to 9. 10. A step of extruding a transparent medium from a plurality of openings provided on the surface of the cylindrical roll based on image information, a step of applying a coloring ink to the extruded transparent medium, and An image recording method, comprising: transferring a transparent medium to an image support; and applying a solidifying liquid to an image portion on the transferred image support.