JPH0298482A - Method and apparatus for forming image - Google Patents

Abstract

PURPOSE:To enable the title method and apparatus to be applied satisfactorily to a recording peripheral apparatus for a computer or the like by supplying a liquid dispersant to an amorphous solid ink material, the adhesiveness of which is varied according to the polarity of a voltage applied between a pair of electrodes, according to an image pattern by a jet system. CONSTITUTION:An ink layer 2 formed by an ink support roll 1 and a coating roll 9 is printed by a liquid dispersant supplied according to an image pattern by ink jet nozzles 11, before making contact with a roll 4. When the parts of the ink layer 2 which are supplied with the liquid dispersant (water) are located between the roll 4 and the ink support roll 1, between which a voltage is applied, the adhesiveness of the parts of the ink layer 2 making contact with the roll 4 is varied, resulting in that the ink is adhered patternwise to the roll 4. The ink image on the roll 4 is then transferred onto a blanket cylinder 5 rotated in press-contact with the roll 4. The ink image on the cylinder 5 is transferred further onto a recording material 7 passed between the cylinder 5 and an impression cylinder 6 rotated in press-contact with the cylinder 5. Thus, an image 8 corresponding to the ink image is formed.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a novel image forming method, a recording material, and an image forming apparatus.

[Conventional technology]

BACKGROUND ART Printing techniques such as lithographic printing, letterpress printing, and gravure printing are used, but there are many difficulties in applying conventional printing techniques to recording peripherals such as computers. For example, the process involved in creating a plate is complicated, making the plate expensive, and when patterning the image and non-image areas on the plate with ink, dampening water is required, causing ink to adhere to the resin on the plate surface. Requires complex operations for sexual control. On the other hand, printers using various recording methods, such as laser beam printers, inkjet printers, thermal transfer printers, wire-tod printers, and daisy-foil printers, are known as recording peripheral devices for computers and other devices. However, there was a problem in that it was not suitable for the large-volume printing achieved by the above-mentioned printing technology in terms of cost and the like. [Problem to be Solved by the Invention] The purpose of the present invention is to create a new image that can be applied to recording peripheral devices such as computers while maintaining printing durability equivalent to that of conventional printing technology. An object of the present invention is to provide a forming apparatus and method. Another object of the present invention is to provide an image forming apparatus and method that is maintenance-free and capable of forming high-quality images, and is fully applicable to recording peripherals such as computers. [Means for Solving the Problems] The present invention includes a first step of applying a liquid dispersion medium according to a desired image pattern to an ink layer made of an amorphous solid ink material containing charged particles by an inkjet method; By passing the ink layer between a pair of electrodes to which a voltage is applied, the adhesion of the portion of the ink layer to which the liquid dispersion medium was applied in the first step is changed, and the desired image pattern is formed on the ink layer. This image forming method includes a second step in which a corresponding difference in adhesion is generated, and a third step in which a portion of the ink layer with stronger adhesion is transferred to a recording medium. The present invention also includes an apparatus for carrying out the above method. That is, a means for forming a layer of an amorphous solid ink material containing charged particles whose adhesion changes depending on the application of a liquid dispersion medium and the application of a voltage; An inkjet device that applies a liquid dispersion medium according to an image pattern, and a pair of positive and negative electrodes. The image forming apparatus includes means for supplying an ink layer between the electrodes and means for applying a voltage to the electrodes. The present invention is characterized firstly by an amorphous solid ink material containing charged particles, and secondly by a pair of electrodes, the adhesion of which changes depending on the polarity of the voltage applied between the pair of electrodes. The image forming apparatus is characterized by having a means for supplying an amorphous solid ink material and a means for applying a voltage between a pair of C8 electrodes, and thirdly, a voltage is applied between the pair of electrodes according to the polarity of the applied voltage. a step of supplying an amorphous solid ink material whose adhesion changes, and applying a voltage between the pair of electrodes,
The method includes a step of predominantly adhering the amorphous solid onto one of the electrodes, and fourthly, the method of changing the adhesion of the ink according to the polarity of the applied voltage includes the step of adhering the amorphous solid onto the ink using an inkjet method. It is characterized in that it is carried out by applying water or other liquid printed in an image pattern. [Example 1] The image forming method of the present invention is such that when a voltage is applied to ink between a pair of electrodes, sticky ink no longer sticks to the electrodes, and conversely, non-sticky ink sticks to the electrodes. Images are formed by taking advantage of the properties of The present invention will be explained below with reference to the drawings. In FIG. 1, the ink carrying roll l is a member having a cylindrical shape and rotating in the six directions of arrows. The roll l is preferably made of a conductive material such as aluminum, copper, or stainless steel.The surface (on the cylindrical surface) of the ink-carrying roll 1 is uniformly coated with ink as a recording material by a coating roll 9 rotating in the direction of the arrow. Formed in thickness. Further, the surface of the ink carrying roll 1 may be a smooth surface, but it is preferable that the surface be appropriately roughened (for example, with a roughness level of IS) in order to further improve ink transport and carrying properties. . Next, before the ink layer 2 formed by the ink carrying roll 1 and the coating hole 9 comes into contact with the roll 4, it is printed with a liquid dispersion medium in accordance with the image pattern by an inkjet nozzle 11. Since an ink using water as a liquid dispersion medium was used, tap water, which can be easily used, was used as the liquid ejected from the inkjet nozzle. Tap water is easily available, does not clog inkjet nozzles, and is harmless, so it is highly preferred as a liquid dispersion medium. Further, since the inkjet nozzle used in the example uses a known system, detailed explanation will be omitted. In the examples, a nozzle from a Canon inkjet printer BJ130 was used. The part of the ink layer 2 to which this water has been applied is then transferred to a roll 4
By applying a voltage between the and ink carrying roll 1,
The adhesion of the ink layer 2 in contact with the roll 4 changes, causing a difference in the adhesion between the ink carrying roll 1 and the roll 4.
Ink is deposited on the roll 4 in an image pattern. The voltage of the power supply 103 is practically 10V to 100V, and even 5V.
A DC voltage of ~50V is preferred. In Figure 1, the roll 4 side is the anode and the ink carrying roll 1 side is the cathode, but depending on the characteristics of the ink used, the roll 4 side may be the cathode and the roll 1 side the anode. Specifically, the voltage application according to No. 03 is preferably applied between the respective rotation axes of the roll 4 and the ink roll 1. The thickness of the ink layer 2 formed on the surface of the ink carrying roll 1 is determined by (the size of the gap between the ink carrying roll 1 and the coating roll 9, the fluidity or viscosity of the ink 2, and the thickness of the surface of the ink carrying roll 1). At the ink transfer position where this roll 1 faces the roll 4,
It is preferably about 0.001-100 mm. If the thickness of the ink layer 2 is less than 0.001 mm, it will be difficult to form a uniform ink layer on the ink carrying roll 1. On the other hand, if the ink layer thickness exceeds 100 mm, it becomes difficult to convey the ink N2 while keeping the surface layer of the ink layer (the layer in contact with the roll 4) at a uniform circumferential speed. It is also difficult to conduct electricity to the roll 4. Next, the ink image on the roll 4 is transferred to the plan cylinder 5, which rotates in the direction of arrow C while being in pressure contact with the roll 4, and the ink image on the plan cylinder 5 is further rotated in the direction of the arrow while being in pressure contact with the plan cylinder 5. The ink image is transferred onto a recording medium 7 (paper, cloth, metal sheet, etc.) passing between impression cylinders 6, and an image 8 corresponding to the ink image is formed on the recording medium 7. In some cases, the ink image on the roll 4 may be directly transferred onto the recording medium 7 without providing the plan cylinder 5. The image forming method of the present invention utilizes the fact that the adhesion of the ink changes depending on the pattern of the electrodes by supplying a specific ink between a pair of electrodes and applying a DC voltage between the electrodes. It is. The image forming method of the present invention can be divided into the following two types depending on the properties of the ink used. That is, (I) a type in which the ink has adhesive properties when no voltage is applied, and the adhesive properties disappear when a voltage is applied; In this case, the ink in the portion to which the liquid dispersion medium was not applied adheres to the roll 4, and a desired recorded image is formed. (II) A type in which the ink has no adhesive properties when no voltage is applied, but becomes adhesive when a voltage is applied. In this case, the ink in the portion to which the liquid dispersion medium has been applied adheres to the roll 4, forming a desired recorded image. Ink used in the image forming method of the present invention will be described below. As mentioned in Types (I) and (II) above, the composition of the materials constituting the ink is determined by whether the ink is made to have adhesive properties or not from the beginning. It can be easily controlled by adjusting the proportions and types of constituent materials. On the other hand, the following several cases can be considered as the mechanism by which the ink changes from adhesive to non-adhesive and from non-adhesive to adhesive due to voltage application. (1) When the adhesion changes due to Crohn's force when voltage is applied.The basic composition of the ink is one consisting of inorganic or organic fine particles and a liquid dispersion medium, and the difference in the chargeability of the fine particles is used. It is. In this case, if the ink is adjusted to have adhesive properties from the beginning and contains particles that are easily charged negatively as fine particles, the ink on the negative electrode side will not stick when a voltage is applied, and the ink will be easily charged positively as fine particles. When the ink is contained, the ink will not adhere to the positive electrode side when a voltage is applied. In addition, if the ink is adjusted so that it does not initially have adhesive properties and contains particles that easily become negatively charged, the ink on the positive electrode side will adhere to the positive electrode when a voltage is applied, and the particles will become positively charged. If a material that is easily contained is included, the ink on the cathode side will adhere to the cathode side when a voltage is applied. (2) When the ink electrolyzes and generates a gas due to the application of voltage, and the adhesion changes. In this case, the ink is adjusted so that it originally has adhesion. When a voltage is applied, the ink generates gas near one of the electrodes, and this gas prevents the ink from adhering to the electrode. In order for the ink to electrolyze and generate gas, the ink may contain a solvent such as water, alcohol, or glycol, or a solvent in which an electrolyte such as sodium chloride or potassium chloride is dissolved. The lower the electrical resistance, the better.
If the zero volume resistance exceeds lo 6 Ω·cm, the volume resistance is preferably 10 11 Ω·cm or less, the amount of current flowing decreases, or a high voltage is required to prevent the amount of current flowing. The ink that adopts the above mechanisms (1) and (2) will be explained below. The ink used in the present invention can be either an ink that sticks or does not stick when no voltage is applied, but from the viewpoint of image density, it is preferable for the ink to move in bulk because the density becomes uniform. Liquids such as water and alcohol have weak cohesive force and cannot provide suitable adhesion.
The ink used in the present invention is such that the ink of the present invention is substantially retained on the platinum-plated stainless steel plate when the ink is applied to a platinum-plated stainless steel plate vertically upright to a thickness of 2 mm. Preferably, the ink of the present invention is sandwiched between two platinum-plated stainless steel plates to make the ink thickness 2 mm, and the two platinum-plated stainless steel plates are separated from each other with no voltage applied. Sometimes it is preferable that the ink adheres to both plates to the same extent. Inks that employ mechanisms (1) and (2) are basically composed of inorganic or organic fine particles and a liquid dispersion medium. The fine particles in the ink make it easier to cut the ink and improve the resolution of the image. The ink material used in the present invention is an amorphous solid of a colloidal sol, and is a non-Newtonian fluid in terms of fluidity. However, in the present invention, the change in adhesion due to voltage must occur only after the liquid dispersion medium is supplied from the inkjet nozzle II. Therefore, the amount of liquid dispersion medium in the ink in the ink reservoir lO or ink layer 2 is kept low. If the change in the viscosity of the ink is due to Coulomb force, the fine particles can be charged by using particles that are easily charged and kneading them in a liquid dispersion medium (described later), for example, in a homogenizer, colloid mill, or ultrasonic disperser. charged particles are generated. Particles to which a positive charge is imparted include metal (A
u, Ag, Cu, etc.) particles, sulfide (zinc sulfide, Zn
S, antimony sulfide Sb2S3, potassium sulfide 2s,
Calcium sulfide CaS, germanium sulfide GeS, cobalt sulfide CO3, tin sulfide SnS, iron sulfide FeS, copper sulfide Cu2S. manganese sulfide MnS, molybdenum sulfide Mo, S, etc.)
Particles, silicic acid (orthosilicic acid) 1<SiO4, metasilicic acid LSiOs, mesotrisilicate H2S1zOs, mesotrisilicate H45i, 05, mesotetrasilicic acid) 1aSi40□, etc.) particles, polyamide resin particles, polyamideimide resin particles, etc. In addition, as the particles to which a negative charge is imparted, iron hydroxide particles, aluminum hydroxide particles,
Fluorinated mica particles, polyethylene particles, montmorillonite particles, fluororesin, etc. can be used. Further, polymer particles containing various charge control agents used as toners for electrophotography can also be used. The above-mentioned fine particles have an average particle diameter of 100 μm or less,
Preferably, particles with a diameter of 0.1 μm to 20 μm, especially 10 μm or less, can be used, and such fine particles may be present in the ink in an amount of 1 part by weight or more, preferably 3 parts by weight to 90 parts by weight, based on 100 parts by weight of the ink. Preferably from 5 parts by weight
It can be contained in an amount of 60 parts by weight. Further, as the liquid dispersion medium used in the present invention, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (weight average molecular weight, about 100
~1000), ethylene glycol methyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl calpitol,
Ethylcarpitol, butylcarpitol, ethylcarpitol acetate, diethylcarpitol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, glycerin, triethanolamine,
Formamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N-methylacetamide, ethylene carbonate, acetamide, succinonitrile, dimethylsulfoxide, sulfolane, furfuryl alcohol,
N,N-dimethylformamide, 2-ethoxyethanol, hexamethylphosphoric triamide (hexamethylphosphoric triamide), 2-nitropropane, nitroethane, γ-butyrolactone, propylene carbonate,
1.2.6-Hexandriol, dipropylene glycol, hexylene glycol, and the like can be used alone or in combination of two or more of them. The liquid dispersion medium preferably contains 1 to 0 parts by weight, more preferably 1 to 0 parts by weight, per 100 parts by weight of the ink. In a preferred embodiment of the present invention, in order to control the viscosity of the ink, 1 to 90 parts by weight, more preferably 1 to 50 parts by weight of the above-mentioned polymer soluble in the liquid dispersion medium is added to 100 parts by weight of the ink material. It can be contained in an amount of 1 to 20 parts by weight, particularly 1 to 20 parts by weight. Such polymers include plant-based polymers such as guar gum, locust bean gum, gum arabic, taragant, carrageenan, pectin, mannan, and starch; microbial polymers such as xanthan gum, dextrin, succinoglucan, and curdlan; gelatin, casein, Animal-based polymers such as albumin and collagen; cellulose-based polymers such as methylcellulose, ethylcellulose, and hydroxyethylcellulose; starch-based polymers such as soluble starch, carboxymethyl starch, and methyl starch; alginic acid-based polymers such as propylene glycol alginate, and alginate; Semi-synthetic polymers such as geosaccharide conductors; vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, sodium polyacrylate; other polyethylene glycol, ethylene oxide, propylene oxide block copolymers , alkyd resin, phenol resin, epoxy resin, aminoalkyd resin, polyester resin, polyurethane resin, acrylic resin, polyamide resin, polyamideimide resin, polyesterimide resin, silicone resin, and other synthetic polymers are used alone or in combination of two or more. be able to. It is also possible to use greases such as silicone grease and liquid polymers such as bolybdenum. The solvent to be replenished by inkjet is preferably one that easily generates gas through electrolysis, such as water, alcohols such as methanol or ethanol, or solvents with hydroxyl groups such as glycerin, ethylene glycol, or propylene glycol. A solvent in which an electrolyte such as sodium chloride or potassium chloride is dissolved is preferably used. The contents of the liquid dispersion medium and fine particles are the same as those described above. In particular, it is preferable to use water or something containing water as the liquid dispersion medium because hydrogen gas is easily generated on the negative electrode side. When water and another liquid dispersion medium are mixed, the content of water is preferably 1 part by weight or more, more preferably 5 parts by weight or more, based on 100 parts by weight of the ink. In the case of ink that generates gas through electrolysis, the fine particles contained in the ink include, in addition to those listed above, silica, carbon fluoride, titanium oxide, carbon black, and the like. In a preferred specific example of the ink used in the present invention, considering the viscoelastic properties of the ink, the fine particles are preferably swellable fine particles that can retain the above-mentioned liquid dispersion medium in the particles.Such swellable fine particles include, for example, Fluoride mica, synthetic mica such as Na-montmorillonite, Ca-montmorillonite, 3-octahedral synthetic smectite, Na-hectolite, Li-hectolite, Na-teniolite, Na-tetrasilicic mica and Li-teniolite,
Silica etc. The above-mentioned fluorinated mica is expressed by the following formula (1
). General formula (1) % formula %) In the formula, W is Na or Li, X and Y are Mg2゜Fe
"s Ni", Mn"'", Al30, Fe", Li0
6-coordinate ion, Z is AI", Si", Ge"
", Fe", 83° or a combination thereof (AI"/Si
'°) represents a cation with a coordination number of 4. The average particle diameter of the swellable fine particles is preferably 75 μm or less in a dry state, more preferably 10 μm or less within a range of 0.8 to 15 μm. The ink may contain colorants such as carbon black and other dyes and pigments that are generally used in the fields of printing and recording, if necessary. When the ink contains a coloring material, the content of the coloring material is preferably 0.1 to 40 parts by weight, more preferably 1 to 20 parts by weight, per 100 parts by weight of the ink. The ink may also contain a color-forming compound that develops color upon application of voltage, and may also contain electrolytes, thickeners, thinners, surfactants, etc. that impart conductivity to the ink. Furthermore, it is also possible for the above-mentioned fine particles themselves to also function as a coloring material.

【Effect of the invention】

According to the present invention, it is possible to reproduce a large number of high-quality printed matter using a printing machine that is easy to maintain and has a printing durability equivalent to that of conventional printing technology. At the same time, since image printing is performed by an inkjet nozzle, it is possible to create a new image forming apparatus that can be applied to recording peripheral devices such as computers.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the image forming method of the present invention. 1... Ink carrying roll 2... Ink layer 4... Roll 5.
... Plan cylinder 6 ... Impression cylinder 7 ... Recorded object 8 ... Ink image 9 ... Coating roll 11 ... Inkjet nozzle

Claims (1)

[Claims] 1) A first step of applying a liquid dispersion medium according to a desired image pattern by an inkjet method to an ink layer made of an ink material whose adhesion changes depending on the application of a voltage; By passing the ink layer between a pair of applied electrodes, the adhesion of the portion of the ink layer to which the liquid dispersion medium was applied in the first step is changed to cause the ink layer to conform to the desired image pattern. An image forming method comprising: a second step of causing a difference in adhesion; and a third step of transferring a portion of the ink layer with stronger adhesion to a recording medium. 2) The method according to claim 1, wherein water is used as the liquid dispersion medium. 3) means for forming a layer of an ink material whose adhesion changes with the application of a voltage; an inkjet device for applying a liquid dispersion medium to an ink layer made of the ink material according to a desired image pattern; and a positive and negative pair. An image forming apparatus comprising: an electrode formed in the form of a cylindrical shape, a means for supplying an ink layer between the electrodes, and a means for applying a voltage to the electrode. 4) The device according to claim 3, wherein the liquid dispersion medium is water.