JPH02235653A - Image recording and its apparatus - Google Patents

Abstract

PURPOSE:To obtain a stable image without tailings even through high speed recording is performed by a method wherein a material of specific critical surface tension or under is bonded to, at least, one side surface of an electrode. CONSTITUTION:Pulse voltage 4 following an image signal is impressed to an electrode 6 (an anode), and the electrode 6 comes in contact with an ink layer 13 on a layer holding belt 5. Then, components 15a, 15b formed by a material having low surface energy at the electrode 6 are made from material of 35dyne/ cm (20 deg.C) or under in critical surface tension, and a conductor 16 is made from high molecular polymer or the like in which gold, platinum, conductive carbon, etc., are dispersed as metallic powder and carbon black.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an image recording method and apparatus, and more specifically, it is useful for recording the output of computers, word processors, etc., and for recording the output of digital communications such as facsimiles. In particular, the present invention relates to an image recording method and apparatus capable of performing high-density and high-speed recording.
[Prior Art] Image recording methods and devices for office equipment are broadly classified into impact type and non-impact type. The latter non-impact recording method has attracted much attention and is now being used in hard copy devices such as word processors and personal computers because it produces less noise during recording. This non-impact recording method or device (simply referred to as a "recording method" or "image recording method" or "recording device" or "image recording device" unless otherwise specified) includes many types including inkjet printers and thermal transfer printers. However, recently, a phenomenon in which the crosslinked structure observed in polyvinyl alcohol-boric acid gel is destroyed by energization [8eLLoezalo, φ et al. [Research on the electrodeposition mechanism of polyvinyl alcohol J. Kollojdn. ZH, 4
6,771 (1984) &. : A recording method using the written tail is attracting attention (Japanese Patent Application Laid-Open No. 63-3027
Publication No. 9, etc.).

The method disclosed in JP-A No. 63-30279 uses a fluid ink in which a colorant is dispersed in a composition in which a hydrophilic polymer is cross-linked with boric acid, and energy is applied to this ink. This is a low-running, low-energy method that changes the adhesion of the ink and transfers it to a recording material such as an intermediate transfer medium or film7, and then transfers it to plain paper to form an image. This is a recording method that reduces running costs, which are disadvantages of conventional thermal transfer recording methods, and can easily produce color. However, when recording is performed using an electrode such as that described in JP-A No. 63-290773, fluidized ink adheres to the electrode, and after energization ends, the ink adhered to the electrode forms a gel layer on the substrate. This is reversely transferred to the transfer medium, and this sometimes causes the phenomenon of "tailing" on the image. [Purpose] The first object of the present invention is to produce a stable image without trailing even if the repeating process 1 is carried out using an ink whose crosslinked structure changes when energized and becomes fluid (fluidity changes). The object of the present invention is to provide a recording method and apparatus that can obtain stable images (particularly stable images even during high-speed recording). A second object of the present invention is to provide an image recording method and apparatus that are easy to operate, inexpensive to manufacture, and easy to maintain. [Structure] The first aspect of the present invention is to provide a layer of gel-like material that contains a colorant and becomes fluid when energized on the surface of a substrate, and after energizing the gel-like material layer with an electrode according to an image signal, the fluidity after energization is The image recording apparatus selectively transfers a colored substance that has become a color to a transfer medium, characterized in that a material having a critical surface tension of 35 dyne/cm (20° C.) or less is bonded to at least one side of the electrode. The second aspect of the present invention is to provide a gel-like material layer on the surface of the substrate that contains a colorant and becomes fluid when energized, and after energizing the gel-like material layer with an electrode according to an image signal, it becomes fluid after energization. An image recording apparatus that selectively transfers a colored substance to a transfer medium is characterized in that a portion of the electrode in contact with a gel-like substance layer has an acute angle.

The third aspect of the present invention is to provide a gel-like material layer on the surface of the substrate that contains a colorant and becomes fluid when energized, and after energizing the gel-like material layer with an electrode according to an image signal, the layer becomes fluid after energization. In an image recording method in which a colored substance is selectively transferred to a transfer medium, when the substrate and the electrode are moved relative to each other and energized, a gel-like substance on the surface of the substrate is used to form one pixel. When the outer periphery of the layer is continuously moved at a circumferential speed V, the contact width between the electrode and the gel-like material layer is W in the feeding direction, and the pixel width in the feeding direction is W, the formula W − w It is characterized by being energized for 40 to 95% of the time of the value of t derived from t = ■. Incidentally, the present inventors applied electricity to the ink layer to bring the ink layer near the anode into a fluid state, and transferred it to bond paper,
After conducting various research and studies on recording methods and devices that can be used to transfer images onto plain paper such as copy paper, we found that: (1) The ink contains a colorant, and when energized, the crosslinked structure changes and becomes fluid. By using materials with properties that change (change), and by devising the electrode when applying electricity to the ink layer, and separately, when the electrode and the ink layer are moving relative to each other, It was confirmed that by keeping the energization time within a certain range, high-quality image recording without trailing could be obtained. The present invention has been made based on this. In the following, the method and apparatus of the present invention will be explained in more detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the entirety of a typical example of an apparatus effective for carrying out the method of the present invention. In the figure, 5 is the base belt 1
This is a gel-like layer holding belt having a gel-like ink layer 13 (an ink layer that is non-fluid before energization and becomes fluid when energized) on the surface of 2 (Fig. 2). The base belt l2 is electrically conductive, and includes, for example, a metal belt made of nickel or the like, a nickel surface plated with gold, platinum, etc., a resin such as polyester in which a conductive substance such as carbon black is dispersed, or a belt made of polyester or the like. Examples include those in which a conductive material such as gold, platinum, or SnO is provided on the surface of a resin belt by a method such as vacuum deposition. The ink layer 13 is composed of a non-fluid gel-like coloring substance (mainly composed of a hydrophilic polymer and a colorant) that contains a colorant and whose fluidity changes when energized.6 These gel-like substances are It can be obtained by crosslinking a water-soluble polymer compound containing hydroxyl groups with borate ions. Here, examples of hydrophilic polymers (water-soluble polymer compounds) include polysaccharides such as low-strength bean gum, guar gum, and pectin, electrolyte polysaccharides such as carrageenan, and synthetic polymer compounds having hydroxyl groups such as polyvinyl alcohol. It will be done.

The boric acid ions that crosslink these hydrophilic polymers can be obtained by dissolving a boric acid ion source compound such as boric acid or borax in water.

The hydrophilic polymers may be used alone or in combination, and the content in the ink layer 13 is related to its molecular weight and solution viscosity, but it is usually preferable to use 1% to 20% by weight. On the other hand, it is preferable that the amount of boric acid ions added to crosslink the ink layer 13 is at least the amount necessary to maintain non-fluidity of the ink layer 13, which does not reach the gel melting point at room temperature. Specifically, the amount of boric acid, borax, etc. to be added as a source of boric acid ions is preferably one-quarter equivalent or more based on the number of crosslinkable hydroxyl groups in the hydrophilic polymer. This increases the crosslinking density of the gel and increases its strength. When using boric acid, gelation can be effectively achieved by simultaneously adding an alkali hydroxide. The ink layer l3 further contains a colorant. As a coloring agent, water-soluble dyes such as those listed in the Color Index as acid dyes, direct dyes, and basic dyes can also be used, but when such dyes are used, a small amount of water may be transferred to the transferred material. However, since the dye is also transferred at the same time, the background is easily smudged.In particular, an apparatus that brings the ink layer 13 into direct contact with the recording paper 2 as shown in FIG. This tendency becomes more pronounced. Therefore, it is preferable to use colorants that are unnecessary for water, such as pigments, oil-soluble dyes, and dispersible dyes. Examples of these colorants include carbon black, triiron tetroxide, titanium black, titanium yellow, molybdenum red, inorganic pigments such as zinc mate, phthalocyanine blue, brilliant carmine lake, and permanent red lake. Auramine Lake, Rhodamine Lake. Examples include organic pigments such as methyl violet lake, quinoline yellow lake, malachite green lake, isoindolinone, quinacridone, perinone orange, perylene scarlet, and perylene maroon. For oil-based dyes and disperse dyes, see the Color Index (The
TV of Dyers and Colo
urists 19'N) and select those with excellent color tone, excellent light resistance, excellent heat resistance, etc., according to your needs. These colorants are preferably added in an amount of 0.2 to 20% by weight of the ink layer. Water can be mainly used as a liquid medium to prepare the liquid for forming the ink layer 13, but ethylene glycol can be used to prevent the evaporation of water from the ink layer 13 and to control the fluidity of the ink layer 13. , diethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dibrobylene glycol, glycerin, and other polyhydric alcohols; diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether, and other polyhydric alcohol ethers; N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, etc. can be used.

Furthermore, a cationic, anionic or nonionic surfactant may be added for reasons such as improving the dispersibility of the colorant. Specifically, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkyl sorbitan esters,
Nonionic surfactants such as polyoxyethylene alkyl amines, glycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene glycol fatty acid esters;
Anionic surfactants such as alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl ether acetic acids, alkylbenzene sulfonates, N-acylamino acid salts, alkyl sulfosuccinates, alkyl phosphates; Cationic surfactants such as quaternary amines such as benzalkonium salts;
Examples include fluorine-based surfactants such as perfluoroalkyl phosphates, perfluoroalkyl carboxylic acid salts, and perfluoro7-alkyl betaines.

Furthermore, if necessary, preservatives, viscosity modifiers, surface tension modifiers, ultraviolet absorbers, etc. modifiers can be added to the ink layer I3. Now, in FIG. 1, 6 is an electrode (anode), and a pulse voltage 4 according to an image signal is applied to this electrode. 20 is the other electrode (cathode =
This electrode is placed in contact with the belt conveying roller 8a, but may be in contact with the ink layer l3 or the base belt (conductive base) 12. However, since the electrode 20 is always kept at ground potential, the current density will be significantly higher at the contact point between the electrode 6 and the ink layer 13 than at other parts of the ink layer 13. Only the nearby ink layer undergoes a change in fluidity.

Recording paper 2 is conveyed to the transfer section by feed rollers 10 and ld, and discharged from the transfer section by feed rollers a and 1b. inserted into the tiny gap between
It comes into contact with the ink layer 13 that has undergone a change in fluidity. Due to this contact, the highly fluid portion (ink) is transferred from the ink layer 13 to the recording paper 2, so that an image is formed there.

Reference numeral 3 denotes an infrared lamp, which is placed close to the gel-like layer holding belt 5 and heats the ink layer 13 after transfer, thereby removing the unevenness of the ink layer 13 that occurs when electricity is applied or not. It is smoothed by melting. The ink layer 13 in the present invention has a characteristic that its fluidity changes even when heated. Instead of the infrared lamp 3, or in combination with it, a heater may be placed in contact with or in the vicinity of the back surface of the base belt. The part surrounded by the broken line 14 is an ink supply section, and although the ink application roller 10 is normally located at a distance from the gel-like layer holding belt 5, it is possible to form a gel-like layer by forming a certain number of copies. When the thickness of the ink layer 13 on the layer holding belt 5 becomes thin, the ink application roller 10 is heated by a heater (not shown) and moved to a position where it comes into pressure contact with the gel layer holding belt 5. The gel ink 9 is heated by an ink application roller 10 to be fluidized and applied to the gel layer holding belt 5. In the figure, 9a is a container for the gel ink 9, 11 is a saucer, and 12 is a squeeze roller. Note that it is desirable to place an appropriate weight on top of the gel ink 9 inside the container 9a. As mentioned earlier, when recording is performed using a stylus, which is not normally used in the image recording apparatus shown in FIG. 1, trailing may occur in the image. Figures 3 and 4 show two examples of electrode structures according to the present invention. 15(a) and (b) have low surface energy such as polytetrafluoroethylene, polytrifluoroethylene, polyhexalfluoropropylene, polydimethylsiloxane, polyvinylidene fluoride, methacrylic acid ester of perfluorooctanol, polyethylene, etc. It is a part made of material. The term "material with low surface energy" here refers to a material with a critical surface tension of 3.
This refers to materials with a density of 5 dyne/cm (20°C) or less. On the other hand, 16 is a conductor such as gold, platinum, conductive carbon,
It is composed of high molecular weight polymers such as polycarbonate and polyacrylic acid ester in which carbon black and metal powder are dispersed. In FIGS. 3 and 4, (a) shows a cross section of the electrode, and (b) is a perspective view. In the figure, A
The surface is in contact with the ink layer.

This figure shows a different electrode structure from those shown in FIGS. 5, 6, and 7. These are all cross-sectional views, and the ink layer l3 on the gel layer holding belt 5 is in contact with the ink layer l3 as shown in the figure.
The ink layer 13 is transported in the direction of the arrow. When the electrode has an acute angle in the vicinity of the gel layer, the member 17 for holding the conductor 16. 18 does not necessarily require the use of low surface energy materials as mentioned above.
Although the use of materials with high surface energy such as glass, ceramic, sin, and boryamide is effective in reducing tailing, it is more preferable to use materials with low surface energy such as those mentioned above. As schematically shown in Figure 8, the first
When the belt 5 shown in the figure is not step-fed pixel by pixel during image formation and is continuously driven at a peripheral speed of V, the contact width between the electrode and the ink layer 13 is W in the feeding direction. When the target pixel width in the feed direction is W, W-W t= (1) ■ is derived (t is the energization time).

Therefore, if it is desired to form a fluidized part with a density of 8 dots/mtm in the ink layer, it is calculated that the conditions of equation (1), that is, the energization time, should be set so that W is 125μ. If the current is turned on for such a set time, the pixel width will actually become larger than the desired pixel width.
To prevent this, it is effective to flow the pulse current for a period of 40 to 95%, more preferably 50 to 90% of the calculated t. If it is less than 40%, it is difficult to obtain the desired pixel width.

Next, examples and comparative examples will be shown.

Example 1 A colored gel-like substance prepared as described below was applied by thermal melting onto a gold-plated substrate on the surface of a nickel belt. Preparation of polyvinyl alcohol solution (A.) Polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.: average degree of polymerization approximately 1500) 5% by weight Pure water Remaining amount The above composition was heated at 60°C, dissolved with stirring, and left to cool. , 10μ
The solution was filtered using a Teflon filter manufactured by the company, and an aqueous solution of vorivinyl alcohol (A) was prepared.

Preparation of pigment dispersion (B) Carbon black (average particle size approximately 0.5μ) 10% by weight
Ethylene glycol 40% by weight
Ilic acid (manufactured by Wako Pure Chemical Industries) 2% by weight
Pure water Remaining amount The above composition was dispersed in a ball mill for 20 hours, coarse particles were removed in a centrifuge, and filtered through a 10 μm Teflon filter to prepare a pigment dispersion (B).

While heating the solution (A) at 60°C and stirring, add the solution (B),
The mixture was allowed to cool to obtain a gel-like substance. The resulting gel was repeatedly washed with water and filtered with suction until the filtrate was no longer cloudy, and the excess solvent was sufficiently removed to obtain a non-flowable black gel-like ink.

On the other hand, polycarbonate film is coated with photoresist.
After applying the layer so that the thickness is about 60 μm, 5 steps 1-
Perform live pattern exposure, perform etching,
I got a tribe-like NOTREGIS 1...Betaan.
．． A gold film was provided on the photoresist surface by vacuum evaporation to a thickness of about 50 μm. The photoresist layer was peeled off from the polycarbonate film by a peeling method to obtain a gold stripe pattern on the polycarbonate film. A polytetrafluene ethylene plate (thickness 1.5 mm) and the above polycarbonate film were bonded together so that the gold pattern overlapped with the polytetrafluene ethylene side, and after thermocompression bonding, the polycarbonate was dissolved and removed with methylene chloride to form a polytetrafluene ethylene plate. A gold stripe pattern was obtained with ethylene. This polytetrafluoroethylene plate (thickness: 1.5 ram) and another polytetrafluoroethylene plate were stacked together, heat-pressed and then cut into lengths of 8 cm, and the end surfaces were polished and shown in Figure 3. An electrode as shown was obtained.

Printing was carried out by attaching the above gel layer holding belt and electrode to the apparatus shown in FIG. The outer peripheral speed of the belt is 20iim
/see.

20V for printing, 3. A 5 msec square wave pulse was used. The resulting image (pixel) had very little trailing.

Comparative Example 1 When an electrode as shown in Figure 3 was printed in the same manner as in Example 1 using a holding member made of glass, the image had significant trailing. Example 2 A gold plate with a thickness of about 100 IT and a polyimide film with a thickness of about 1"0 μm were bonded together using an epoxy adhesive so that each layer had 200 layers.
An electrode material with a width of ++ was obtained. By cutting this material and gluing it together, electrodes with a width of 110 mm and 1000 conductors were obtained. This electrode was cut so that the temperature near the tip was 30° C. as shown in FIG. 5, and the tip was polished to a radius of curvature of about 50 μm. This electrode was attached to the printing device shown in FIG. 1 at a position such that the tip pushed down the approximately Sμ gel layer, and the voltage was set at 30V and 4.5V. 2rase
When printing was performed using a rectangular wave pulse of c, there was only slight trailing on the image.

Example 3 Using the electrode of Comparative Example 1, printing was performed using the apparatus shown in FIG. The etching width between the electrode and the gel layer is approximately 50 μm, and the pulse width calculated to obtain a pixel with a width of 125 μIII is 3.75 m when the circumferential speed is 20 + + + m8c (
sec. We searched for the optimal conditions by changing the pulse width under these conditions, and the result was approximately 3. The desired pixel width was obtained with the least tailing at 3IIlsec.

Furthermore, when the circumferential speed was varied from 5 to 100 mm+/see, and the input pulse voltage and pulse width were changed, the optimum pulse application time was similarly searched, and when the circumferential speed was increased and the pulse voltage was increased, the calculation It has been found that good images can be obtained when the rainbow is pulsed for a short period of time. As a result, the desired pixel width was obtained without tailing when the pulse was applied for 40 to 95% of the calculation time.

〔effect〕

According to the present invention, the following effects are brought about.

(1) Even if the fluidized ink adheres to the electrode and the fluidized ink adheres to the surface of the unfluidized ink even after the pulse voltage is applied, the pulse application time will be shortened accordingly. Therefore, the desired pixel width can be obtained without causing trailing. (2) As there is a member with low surface energy in contact with the conductor as shown in Figures 3 and 4, the fluidized ink only adheres to the conductor, so it is not fluidized. Because the gel layer is easily cleaned, trailing in images is significantly reduced. (3) As shown in Figures 5, 6, and 7, since the part of the electrode that contacts the gel layer is at an acute angle, the part of the electrode that is wetted by fluid ink is reduced, resulting in excess The amount of ink adhering to the ink is also reduced, and in this case too, it is easily cleaned by the unfluidized gel layer, so the trailing of the image is significantly reduced. (4) The above (1), (2) and (3) are effective even when used alone, but it is recognized that the effect is further increased by combining all or two of them. Further, although FIG. 1 shows an example in which the gel layer is directly transferred to the recording paper, even if the apparatus is configured such that the gel layer is transferred once to the intermediate transfer body and then transferred from the intermediate transfer body to the recording paper,
It is clear that the invention has similar advantages.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a typical example of the device of the present invention. FIG. 2 to FIG. 7 are diagrams showing a plurality of examples of electrodes. FIG. 8 is an explanatory diagram for obtaining a desired pixel width. 2... Recording paper 3... Heater 5...
・Gel layer holding belt 6... Electrodes +1a, 8b...
・Substrate moving roller IO... Ink application roller l2... Base belt 13... Ink layer (colored gel-like substance M) Fig. 4 Fig. 8

Claims (1)

[Claims] 1. A gel-like material layer containing a colorant that becomes fluid when energized is provided on the surface of the substrate, and after electricity is applied to the gel-like material layer using an electrode according to an image signal, the fluidity becomes fluid after energization. In an image recording apparatus that selectively transfers a colored substance to a transfer medium, at least one surface of the electrode has a critical surface tension of 3.
An image recording device characterized by bonding materials of 5 dyne/cm (20°C) or less. 2. A gel-like material layer containing a colorant that becomes fluid when energized is provided on the surface of the substrate, and after energizing the gel-like material layer with an electrode according to an image signal, the colored material that has become fluid after energization is selectively removed. What is claimed is: 1. An image recording device for transferring an image to a transfer medium, characterized in that a portion of the electrode in contact with a gel-like material layer has an acute angle. 3. A layer of gel-like material containing a colorant that becomes fluid when energized is provided on the surface of the substrate, and after energizing the gel-like material with an electrode according to an image signal, the colored material that has become fluid after energization is selectively removed. In an image recording method for transferring an image to a transfer medium, when the substrate and the electrode are relatively moved and energized, the outer periphery of the gel-like material layer on the surface of the substrate is continuously formed to form one pixel. When it is moved at a circumferential speed v, the contact width between the electrode and the gel material layer is w in the feeding direction, and the target pixel width in the feeding direction is w, there are formulas ▲ mathematical formulas, chemical formulas, tables, etc. ▼ An image recording method characterized in that electricity is applied for a time that is 40 to 95% of the value of t derived by .