JPH0357649A - Image forming device - Google Patents

Abstract

PURPOSE:To make possible the formation of a thin ink layer without fouling the interior of a device after recovering a surplus ink by providing an ink image forming plate, at least a pair of conductor members which feeds ink and a power supply which applies a voltage, and moving the ink in a direction opposite to a direction where it is supplied to the plate by voltage application. CONSTITUTION:Ink layer thinning rollers 15,16 thin an ink layer supplied from a coating roller 9 while the ink is transported to a bearing roller 1. Electrodes 19 are provided at both ends of the bearing roller 1 and the ink layer thinning rollers 15,16 along the circumference, and a voltage applied to the electrodes 19 is applied from a direct current power supply 11 so that the ink moves from the bearing roller 1 to the coating roller 9. The returned ink is recovered into an ink reservoir 10 by side dams 17,18 at the both ends of the ink reservoir 10, and again is allowed to stick to the ink layer thinning rollers 15,16 squentially. After this, a voltage is applied to an area between the plate 5 and the ink bearing roller 1 from the power supply 11 to change the sticking properties of ink and form an ink image on the plate 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image-forming device using ink whose adhesion force changes when energized.

[Conventional Technology 3 Printing technologies include lithographic printing, letterpress printing, gravure printing, and the like. These printing methods require complicated processes to make the plates, which can make them too expensive or
Until now, dampening water was required to butter the ink in the image and non-image areas on the plate, and complicated operations were required to control the ink adhesion of the resin on the plate surface. There are many difficulties in applying this printing technology to recording peripheral devices such as computers.

On the other hand, methods that use laser beam printers, inkjet printers, thermal transfer printers, wire dot printers, and daisy foil printers as recording peripherals for computers and other devices do not allow for the large amount of paper that can be achieved using the printing technology described above. Printing has some problems, such as cost issues.

Furthermore, although ink jets have low consumable costs, they eject low-viscosity liquid ink from thin nozzles, so they have the disadvantage that they tend to solidify and clog when not in use. Furthermore, since the ink used in inkjet has a low viscosity, it tends to bleed and blur images after the ink is transferred to the paper.

In order to solve the above-mentioned problems, the present inventors first developed an image forming method that allows for easy plate production and low-cost large-volume printing (Japanese Patent Application No. 1261-1982).
7 and Japanese Patent Application No. 63-12618). This image forming method utilizes the property that adhesive ink does not adhere to the electrodes when a voltage is applied to the ink by a pair of electrodes, and uses one electrode with a desired pattern as a plate and connects it to the opposite electrode. By supplying a specific ink between the electrodes and applying a DC voltage between the pair of electrodes, an image corresponding to the pattern of the electrodes is produced.

[Problem that the invention is trying to solve]

However, there is still room for improvement in the process of supplying ink to the plate. For example, in the process of thinning the ink supplied to the plate, excess ink may migrate to the ends of each roller, drip from the ends of the rollers, and contaminate the inside of the apparatus.

The present invention was made in view of the above circumstances, and it is possible to thin the ink layer without contaminating the inside of the device, while maintaining the same level of printing durability as that of conventional printing technology. At the same time, it is an object of the present invention to provide an image forming apparatus that can be applied to recording peripheral devices such as computers.

[Means to solve the problem]

As a result of intensive studies to solve the above problems, we found that the invention includes at least a plate for forming an ink image, at least a pair of conductive members that supply ink to the plate, and a power supply that applies voltage between the pair of conductive members. However, the present invention has completed an image forming control device characterized in that means is provided for moving the ink in a direction opposite to the direction in which the ink is supplied to the plate by applying a voltage to the conductive member.

An image forming apparatus of the present invention will be described with reference to the drawings.

In FIG. 2, the ink carrying roll 1 is a member that has a cylindrical shape and rotates in eight directions indicated by arrows. The roll 1 is preferably made of a conductive material such as aluminum, copper, or stainless steel. On the surface (on the cylindrical surface) of the ink carrying roll 1,
Coated with conductive silicone rubber. Further, the surface of the ink carrying roll l made of the above material may be a smooth surface, but it is preferable that the surface be appropriately roughened (for example, roughness Is It is preferable that the The ink carrying roll l is connected to one end of a DC power supply l1.

In the figure, 15 and 16 are ink thin layer rollers. These rollers 15 and 16 thin the ink to a thickness of 2 to 3 μm while being conveyed to the ink carrying roller 1 supplied from the coating roller 9. Since these methods have been conventionally used in printing presses, detailed explanations will be omitted.

Furthermore, a feature of the present invention is that electrodes 19 are provided along the circumference as shown in FIG. The ink of the present invention is applied to the ink carrying roller 1 in sequence.
This is due to the fact that the voltage was applied so as to move from the coating roller 9 to the coating roller 9. For ease of explanation, FIG. 1 schematically shows the rollers in the longitudinal direction by arranging them in a line.

The ink that has returned onto the coating roller 9 flows through side dams (17. in the figure) provided at both ends of the ink reservoir 1O.
18) is collected into the ink reservoir 10.

Furthermore, voltage is applied to the electrodes 19 at both ends of the thin-layer rollers 15, 16 by making conduction between the roller shafts of the thin-layer rollers 15, 16 and the electrodes, and applying voltage to the thin-layer roller shafts.

These steps are performed to prevent excess ink from moving and accumulating at both ends of each roller when the ink is thin, causing phenomena such as dripping from both ends of the rollers and staining the inside of the machine.

Ink is supplied to the surface of the ink carrying roll 1 by a coating roll 9 rotating in the direction of arrow E, which transfers ink from an ink reservoir IO to a thin layer roll 15. This is done by sequentially depositing on 16 surfaces.

Thin roll 15. The surface material of 16 may be any conventionally used material except for the electrodes at both ends described above. A plate 5 wound around a plate roll 4 is in contact with the conductive coating member on the surface of the ink carrying roll l.

The plate roll 4 is rotating in the direction of arrow B in the opposite direction to the ink carrying roll 1. The plate 5 has a desired non-conductive pattern l3 made of an insulating material on a base material l2 made of a conductive material such as metal.
is provided. The material of the base material 12 includes aluminum, copper, stainless steel, platinum, gold, chromium,
Metals such as nickel, phosphor bronze, and carbon, or conductive polymers, or metal fillers dispersed in various polymers are used. Materials for the non-conductive pattern 13 include thermal transfer recording materials, electrophotographic toner images, vinyl polymers and other natural, synthetic or polymeric materials.

In this way, by applying a voltage between the plate 5 and the ink carrying roll l from the power supply 1l, the adhesion of the ink that comes into contact with the conductive part of the plate changes, and the difference in adhesion causes the plate 5 to
Ink is deposited in a pattern on top to form an ink image. The voltage of the power source 11 is practically a DC voltage of 3 to 80V, preferably 5 to 80V. 10Hz
= l O O K Hz AC bias voltage (10
By further applying V~IOOV), the image quality can be made even sharper.

The voltage applied to the thin rollers 15 and 16 is also applied to the thin roller l6 on the tenth side of the ink carrying roller 1, and the voltage applied to the thin roller 15 is on the tenth side of the voltage of the thin roller 16.
The coating roller 9 is set to be closer to the side than the thin layer roller 15.

In Figure 2, the plate 5 side is the cathode and the ink carrying roll l side is the anode, but depending on the properties of the ink used, the plate 5
The side may be used as an anode and the roll L side may be used as a cathode. Naturally, it goes without saying that the negative electrodes at both ends of the thin layer rollers 15 and 6 have opposite polarities.

Specifically, the voltage from the power source 11 may be applied between the respective rotation axes of the printing roll 4 and the ink carrying roll l.

Next, while pressing the ink image on the plate S with the plate 5,
Further, the ink image 14 on the plan cylinder 6 is transferred to a recording medium 8 (paper, (cloth, metal sheet, etc.) to form an image corresponding to the ink image 14 on the recording medium 8. In some cases, the ink image on the plate 5 may be directly transferred onto the recording medium 8 without providing the plan cylinder 6, but if the plan cylinder 6 is provided, the material of the plan cylinder 6 will prevent the plate from being worn out and deteriorated. Furthermore, an image having the same pattern as the plate can be obtained on the recording medium.

In addition to the above, the insulating film formed on the substrate can be used as a plate.
Using a substrate coated with an insulating layer containing a silver compound, which forms a conductive pattern by etching through discharge breakdown,
There are methods that form conductive patterns by depositing silver particles.

The adhesion of the ink used in the present invention is changed by applying a voltage between a pair of conductive members. That is, the ink used in the present invention has adhesive properties when no voltage is applied, and the adhesive properties disappear when a voltage is applied.

The mechanism by which ink adhesion changes due to voltage application as described above is thought to be as follows.

That is, when electricity is applied by applying a voltage, the ink is electrolyzed to generate gas, and the adhesion properties change.

The ink is adjusted to have adhesive properties from the beginning, and when a voltage is applied, the ink generates gas near one electrode, and this gas prevents the ink from adhering to the electrode. In order to generate gas through electrolysis, the ink contains 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 of the ink, the better, and the volume resistivity is preferably 10'Ω·am or less. 10'
If it exceeds Ω·cm, the amount of current flowing decreases, or a high voltage is required to prevent a decrease in the amount of current flowing, which is not preferable.

As for the ink of the present invention, low viscosity liquids such as water and alcohol have weak cohesive force and cannot provide suitable adhesive force. In the present invention, the ink is such that, for example, when the ink is applied to a platinum-plated stainless steel plate vertically upright to a thickness of 2 mm, it is substantially retained on the platinum-plated stainless steel plate. I love this. In addition, ink was sandwiched between two platinum-plated stainless steel plates to make the ink thickness 2 mm, and when the two platinum-plated stainless steel plates were separated from each other with no voltage applied, the ink was the same on both plates. It is preferable that it adheres to a certain extent.

The above-mentioned ink is basically composed of a liquid dispersion medium having the above-mentioned adhesion force, but the ink also contains fine particles to improve ink cutting and improve image resolution. It doesn't matter.

The inks used in the present invention are colloidal sol amorphous solids and are non-Newtonian in flowability.

Considering the viscoelasticity of the ink, the fine particles are preferably swellable fine particles that can retain the above-mentioned liquid dispersion medium in the particles. Liquid dispersion media include water; alcohols such as methanol and ethanol; glycerin, ethylene glycol,
A solvent having a hydroxyl group such as propylene glycol; or a solvent in which an electrolyte such as sodium chloride or potassium chloride is dissolved is preferable.

When water and another liquid dispersion medium are mixed, the content of water is 1% by weight or more, preferably 5% by weight or more based on the ink.

Swellable fine particles include, for example, Na-montmorillonite, Ca-montmorillonite, 3-octahedral synthetic smectite, Na-hectorite, Li-hectorite, Na-
Taeniolite, Na-tetrasilisikkumai, Li-
Examples include fluorinated mica such as taeniolite, agglomerated mica, and silica.

The above-mentioned mica fluoride can be represented by the following general formula (1).

General formula (1) Wn+ (x, y) n2 (z4010) F2
In the formula, W is Na or Li, X and Y are Mg2-F
e", Ni", Mn", Aj72+Fe" L
6-coordinate ion such as ++, Z is Af"Si"G
e” “Fe” “B” or a combination thereof (Al
For a cation having a coordination number of 4, such as 3+/Si4+), nl represents 1-1/3 and n2 represents 2.5 to 3. The average particle diameter of the swellable fine particles is 75 μm or less in a dry state, preferably 0.8 to 15 μm, particularly preferably 8 μm or less.

Further, the ink may contain a coloring agent such as a dye or pigment, such as carbon black, which is generally used in the field of printing and recording, if necessary. When the ink contains a colorant, the content of the colorant is O. 1~
40% by weight, preferably 1-20% by weight. A color-forming compound that develops color upon application of voltage may be contained instead of or together with the colorant. In addition, the ink may contain an electrolyte, thickener, thinner, surfactant, etc. that impart conductivity. Further, it is also possible to cause the above-mentioned fine particles themselves to also function as a coloring material.

[Example 1] 250 g of glycerin, 250 g of water, carbon black (
Pigment) (manufactured by Cabot, USA, "Sterling SRJ")
50g and mixed with an attritor for 4 hours. 250 g of lithium taeniolite was added to this mixture and mixed for 2 hours using a kettle to obtain an ink.

Printing was performed using the ink prepared above using the printing apparatus shown in FIG.

As the ink carrying roll 1, a stainless steel cylindrical roll with a diameter of 30 mm is used.
As shown in FIG. 1, an electrode 19 with a width of about 10 mm was provided on both ends of the surface of the ink carrier roll 1, and the entire surface of the ink carrying roll 1 except for the electrode 19 was coated with conductive silicone rubber to a thickness of about 2 mm. . The conductive silicone rubber used is NVR-88AB manufactured by Nitto Denko ■, and has a volume resistivity of approximately 102 Ω·cm. The surface of the electrode 19 with a length of 10 mm at both ends is plated with platinum.

Similarly, the thin layer rollers 15 and 16 and the coating roller 9 have both ends 1 similar to the structure of the ink carrying roller l.
An electrode l9 whose surface is plated with platinum of 0 mm is provided,
The center part was coated with fluororesin to a thickness of about 2 mm.

Incidentally, the ink carrying roller and the thin layer rollers 15 and 16
As shown in FIG. 1, the electrode 19 portion of the coating roller 9 is approximately 0.0 mm in diameter from the central portion. 1 mm
It's thin. This is to prevent leakage due to voltage application due to roller contact.

In addition, as the plate roll 4, an iron cylindrical roll with a diameter of 30 mm whose surface is plated with hard chrome is used.
A plate 5 on which a non-conductive pattern 13 was formed using photoresist 1 was wound on top of the copper base material.

Between the ink carrying roll l and the coating roll 9,
The ink mentioned above was added. 5m of ink carrying roll 1
The plate roll 4 is rotated in the direction of arrow A at a circumferential speed of m/see.
were rotated at the same speed in the direction of arrow B.

Plate roll 4 is connected to main body ground, ink carrying roll 1
A voltage of +30V is applied from the power supply 11 using the electrode as an anode, and +60V is applied to the thin-layer roll l6, and +60V is applied to the thin-layer roll l5.
A voltage of 90 V and +120 V is applied to the coating roller 9 from the same power source l1.

With the above configuration, ink is deposited on the non-conductive pattern l3 of the printing plate 5 at the center of the ink carrying roller 1, and the cylinder 6 rotates in the direction of arrow C while being in pressure contact with the printing roll 4.
An ink image l4 is formed on the recording material by transferring the ink onto the recording material passing between the impression cylinder 7 rotating in the direction of arrow D while being in pressure contact with the blank cylinder 6. Ta.

On the other hand, the ink carrying roller 1 and the thin layer rollers 15 and 16
At both ends of the coating roller 9, the ink becomes surplus due to the thinning of the ink layer, and the ink that has moved to both ends moves in the direction of the coating roller 9 (upstream direction) between the respective rollers due to voltage application at the electrode section. , and was finally collected in the ink reservoir 10.

Of course, since the center portions of the thin layer rollers 15, 16 and the coating roller 9 are coated with an insulator as described above, the movement of the ink does not occur.

It is not necessary to apply voltage to both ends of the roller all the time, and it may be applied at regular intervals depending on the amount of ink.

[Example 2] Ink carrying roll l1 thin layer roller 15, l shown in FIG.
6. Image formation was performed using a coating roller 9.

In this embodiment, the width of the electrodes at both ends of each roll becomes wider toward the upstream side, as shown in the figure. In the embodiment, the width is increased every 2 mm. This is done in consideration of the fact that the amount of recovered ink increases as one goes upstream.

The same ink as in Example 1 was used. The conductive silicone rubber coated on the ink carrying roll 1 is NVR-88AB manufactured by Nitto Denko, as in the previous embodiment. This conductive coating is not limited to silicone rubber, and even fluorine-based conductive resins, for example, can be used for practical purposes.

Image formation was then carried out in the same manner as in Example 1, and a high quality ink image was formed on the recording medium.

〔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.

More specifically, by using the ink carrying roll of the present invention, the surplus ink that has moved to both ends of each roll can be collected into the ink reservoir using the energizing characteristics, while maintaining the adhesion between the plate and the ink. A highly reliable printing machine can be provided with a simple configuration.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of an ink carrying roll and a thin layer roll used in the present invention, Fig. 2 is a side view showing an example of an apparatus of the present invention, and Fig. 3 is an ink carrying roll used in the present invention. and FIG. 7 is a plan view showing another example of the thin layer roll. l... Ink carrying roll 2... Roll 4...
Plate roll 5... Plate 6... Plan cylinder
7... Impression cylinder 8... Recorded object 9...
・Coating roll 10...Ink reservoir 1
l...DC power supply l2...Base material l3.
...Non-conductive pattern 14...Ink image l5
... Thin layer roller l6... Thin layer roller l7.
...Side dam 18...Side dam, l9...
・Electrode 1V

Claims (2)

[Claims] (1) The plate includes at least a plate for forming an ink image, at least a pair of conductive members that supply ink to the plate, and a power supply that applies a voltage between the pair of conductive members, and An image forming apparatus comprising means for moving the ink in a direction opposite to the direction in which the ink is supplied to the plate. (2) Claim 1, wherein the means for moving the ink is electrodes provided at both ends of the roller-shaped conductive member.
The image forming apparatus described above.