JPH03130158A - Ink-jet-printer - Google Patents

Abstract

PURPOSE:To prevent the deterioration of printing quality by installing a pair of electrode plates, in which printed recording paper is passed in a space forming an AC electric field, as a dielectric heating apparatus. CONSTITUTION:A pair of electrode plates composed of a beltlike electrode plate 11 curved in the short-side direction and a platen 12 made of a cylindrical metal are mounted at the post-stage of a recording head 40 in a shape that recording paper 43 having the position of printing is held from both sides, and a dielectric heating apparatus is constituted of a pair of the electrode plates and a circuit section 10. A high-frequency electric field is shaped in the space which is formed by opposingly arranging the electrode plate 11 and the platen 12 made of the metal, and Joule heat is generated by dielectric polarization generated in ink dropped onto the surface of recording paper 43 when the position of printing of recording paper 43 is passed in the high-frequency electric field. Consequently, the position of printing is dried quickly by heating by the Joule heat. Accordingly, the deterioration of printing quality due to the rubbing of the position of printing is prevented, thus ensuring excellent printing quality.

Description

[Detailed description of the invention] [Industrial application field]

In particular, this invention is an inkjet printer that can rapidly dry printed areas on recording paper using a dielectric heating method.
Regarding printers.

[Conventional technology]

Inkjet recording head (hereinafter referred to as recording head)
Regarding the two methods of conventional printers equipped with
This will be explained with reference to FIGS. FIG. 4 is a perspective view of the main parts of the printer, and FIG. 5 is a perspective view of the main parts of another printer. In FIG. 4, the recording head 40 can run along a guide rail 41 in the direction of the arrow. As the cylindrical platen 42 rotates in the direction of the arrow, the recording paper 43 comes into contact with a part of its cylindrical surface and is fed out, and printing is performed on the cylindrical surface. In this printer, it is difficult to feed thick paper such as envelopes and print on them due to the recording paper feeding mechanism. In FIG. 5, the recording head 50 can run along a guide rail 51 in the direction of the arrow. The recording paper 53 is fed out along the upper surface of the planar platen 52 by rotation of each roller 55, 56 in the direction of the arrow, and printing is performed at a location facing the downward ink nozzle of the recording head 50. This printer has the advantage that it is possible to feed out thick paper such as envelopes, and there are fewer restrictions on the thickness of the recording paper.

[Problem to be solved by the invention]

Generally, there are two types of recording paper: special paper and plain paper. There are two further types of special paper: non-water resistant paper (non-size paper) that is not treated to make it water resistant or has only a weak degree of water resistant treatment, and paper that is coated with fine silica or a water-soluble binder on the surface of the paper. It is broadly classified into chemically treated paper (coated paper). The former, non-waterproof treated paper, absorbs ink quickly, while the latter, film-treated paper, has a coating that absorbs ink.
Hold. In any case, in the case of special paper, the ink dries quickly, which prevents deterioration in print quality due to rubbing. For plain paper, in order to improve printing (recording) characteristics and water resistance,
Waterproofing treatment is performed to fill in the gaps on the surface and inside of paper, and the waterproofing agent used in this treatment acts as an obstacle to ink penetration and delays ink absorption and drying. Therefore, when using special paper as the recording paper, there is no problem in print quality. However, when using plain paper, it absorbs ink for the reasons mentioned above. Since it takes a long time to dry, there is a risk that the print area will get dirty due to rubbing with the feed roller, etc., and the print quality will deteriorate. Conventionally, countermeasures have been taken to improve the physical properties of the ink and to heat dry it by installing a heater. The former method of improving ink physical properties can speed up drying by lowering the surface tension, but on the other hand, the bleeding of printed dots becomes larger, causing another problem in print quality. Also, the ink p
There is a method of making H 13 to 14 strong alkaline and forcibly dissolving the fibers of the recording paper to accelerate ink absorption, but this method causes safety problems. In the latter method of installing a heater, a heater with metal resistance wire embedded in silicone rubber is placed around the platen to dry the recording paper, but it takes up space and the heating temperature is around 40 to 60°C. Therefore, it is difficult to dry the ink quickly. The object of this invention is to provide an inkjet printer that solves the problems of the conventional technology and that can rapidly dry the printing area of recording paper even when V-feeding paper is used, thereby preventing deterioration of print quality due to scratches. Our goal is to provide the following.

[Means to solve the problem]

In order to solve this problem, inkjet printers according to the present invention are arranged facing each other, an alternating electric field is formed in this facing space, and a recording paper with printed information passes through this facing space. A pair of electrode plates is provided as a dielectric heating device.

[For use]

An alternating electric field is formed in the space in which the pair of electrode plates face each other, and when the printed area of the recording paper passes through this alternating electric field, Joule heat is generated due to the induced polarization that occurs inside the ink.
The printed area is rapidly dried by heating with this Joule heat.

【Example】

Embodiments of an inkjet printer according to the present invention will be described below with reference to the drawings. This embodiment uses a method of rapidly drying the ink using dielectric heating. FIG. 1 is a perspective view of essential parts of a first embodiment, and corresponds to the conventional example shown in FIG. 4. The first embodiment is different from the conventional example in that a recording paper 43 having a printing area is sandwiched from both sides at the rear stage of a recording head 40. A counter electrode plate consisting of a platen 12 is provided, and a dielectric heating device is constituted by this counter electrode plate and a circuit section 10, which will be described in detail later. Incidentally, members of the first embodiment that are the same as those in the conventional example are given the same reference numerals. Now, a high frequency electric field is formed in the space where the electrode plate 11 and the metal platen 12 face each other. When the printed portion of the recording paper 43 passes through this high-frequency electric field, Joule heat is generated due to dielectric polarization generated inside the ink dropped onto the surface of the recording paper 43. The printed area is rapidly dried by heating with this Joule heat. Note that the energy of dielectric heating is generally proportional to the frequency of the voltage applied to the counter electrode plate, and inversely proportional to the distance between the electrodes. FIG. 2 is a perspective view of the main parts of the second embodiment, which corresponds to another conventional example shown in FIG. The second embodiment is different from other conventional examples in that a recording paper 53 having a printing area is sandwiched from both sides at the rear stage of a recording head 50, and a band-shaped electrode plate 21 and a flat metal platen 22 are provided. A counter electrode plate is provided, and the counter electrode plate and the circuit section 10 constitute a dielectric heating device. Incidentally, members of the second embodiment that are the same as those of another conventional example are given the same reference numerals. The operation of this second embodiment is exactly the same as that of the first embodiment. 1st. The circuit section 10 commonly used in each of the second embodiments will be described with reference to FIG. 3, which is a circuit diagram of the dielectric heating device. In FIG. 3, the circuit section 10 consists of three parts A, B, and C, each surrounded by a dashed line. Part A
is a power supply section, and its voltage is normally 12V. Part B is an oscillation circuit in which the overtone of the crystal oscillator X is extracted by a tuning circuit consisting of a coil L and a capacitor C. Part C is a high frequency band class C amplifier circuit that utilizes the flywheel effect. The counter electrode plate 1, which is the final stage, is a heating section, and a high frequency electric field is formed in this opposing space. This counter electrode plate 1 is the same as the electrode plate 11 in the first embodiment. 120 pairs of platens, electrode plates 21 in the second embodiment. Each corresponds to a pair of platens 22. Note that the circuit section 10 and the counter electrode plate 1 constitute a dielectric heating device. Further, the unexplained symbol R in FIG. 3 represents a resistor, the symbol T represents a transformer, and the symbol Tr represents a transistor. 1st. In each of the second embodiments, tests were carried out under the following common dielectric heating conditions. The ink in the printing area dries instantly when it passes through the opposing space of the counter electrode plate after printing, and the ink in the subsequent feeding area is Even when it came into contact with the roller, there was no rubbing or staining, and the print quality was extremely good. Conditions related to dielectric heating: (1) Distance between electrodes...1rM1 (2) Frequency -8Xl06Hz (3) Source voltage...12V (4) Surface tension of ink...65 dyn 7
cm (5) Recording paper: plain paper for copying machines

【Effect of the invention】

As explained above, in this invention, a pair of ! An alternating electric field is formed in the space facing the electrode plates, and when the printed area of the recording paper passes through this alternating electric field, Joule heat is generated due to dielectric polarization that occurs inside the ink on the surface of the recording paper.
The printed area is rapidly dried by heating with this Joule heat. Therefore, the present invention has the following superior effects compared to the conventional technology. (1) Deterioration of print quality due to rubbing of the printed area is prevented and good print quality is guaranteed. Of course, there is no problem in feeding the recording paper. (2) Since plain paper can be used as recording paper, it is convenient in terms of cost and availability. (3) It is advantageous to be able to use ink that has a high surface tension and allows for good printing, but is difficult to dry and may cause deterioration in printing quality due to rubbing. (4) Only a pair of electrode plates are provided near the recording paper, and the main body of the dielectric heating device can be installed at a different location, so flexibility is provided to the printer configuration, resulting in space savings. (5) Since it uses a dielectric heating method, it is easy to control the heating temperature, and therefore the printed area can be dried under optimal conditions. (6) Since it uses a dielectric heating method, there is no risk of contaminating the installation environment.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main parts of the first embodiment of the present invention, Fig. 2 is a perspective view of the main parts of the second embodiment, Fig. 3 is a circuit diagram of the dielectric heating device, and Fig. 4 5 is a perspective view of the main parts of one conventional example, and FIG. 5 is a perspective view of the main parts of another conventional example. Symbol explanation 1: Counter electrode plate, lO: Circuit section, 11, 21: Electrode plate, 12.22 Nibraten, 40.50: Recording head, 43.53: Recording paper. 2nd ro 4th fishing r fupi diagram

Claims (1)

[Claims] 1) It is characterized by comprising a pair of electrode plates as a dielectric heating device, which are arranged opposite to each other, in which an alternating electric field is formed in the opposed space, and through which a printed recording paper can pass. inkjet printer.