JPS6295236A - Printing apparatus - Google Patents

Abstract

PURPOSE:To enhance reliability by securing the stability in the supply of a current, by using tungsten as the material of a recording needle and applying oxidizing treatment to the surface of said recording needle. CONSTITUTION:Not only an ink film 10 having a resistance layer 3 and a meltable ink layer 1 but also a plurality of recording needles 5 and a recording head comprising a recording substrate 6 having said recording needles 5 mounted on one surface thereof are used and a current is supplied to the resistance layer 3 to generate heat and said meltable ink layer is melted and transferred to transfer paper to form a picture element to perform recording. The surfaces of the recording needles 5 to be formed on the recording substrate 6 are covered with an insulating layer 40 electrically insulating said recording needles 5 and the material of the recording needles 5 is formed of tungsten to apply oxidizing treatment to said needles and the surface of each needle is converted into tungsten oxide to form the insulating layer 40. The end surface of the leading end of each recording needle 5 is polished to secure a current supply part 50 and, because there is the insulating part 40, a current can be always supplied only to the current supply part 50 and current supply recording can be always stably performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing device, and more particularly to a printing device using an electrically conductive thermal transfer recording method.

[Prior art] There was a "printing device" (Japanese Patent Application No. 186496/1983) as a technology that realized a high-speed, high-quality, low-cost full-color printing device using the conventional current-carrying thermal transfer recording method. .

The outline will be explained below.

FIG. 3 shows a cross-sectional view of the structure of the ink film 10 for electrically conductive thermal transfer recording. Melting ink layer 1 is a layer in which pigment or pigment and dye are dispersed in wax at 60 to 80°C.
The support layer 2, which has the property of melting at a certain temperature, is a resin film made of PET or the like or a capacitor paper. The resistance layer 3 is a layer in which fine carbon powder is dispersed in a resin and is electrically conductive. FIG. 4 shows a recording section of a conventional electrically conductive thermal transfer recording head. The recording section of the recording head 4 is composed of a plurality of recording needles 5 and a recording substrate 6 provided with the recording needles.

The angle 20 formed by the end surface 7 of the recording substrate and the recording substrate 6 is defined as θ1 as shown in the figure. FIG. 5 shows the arrangement and pressing method of the conventional recording head 4 and platen 11. Platen 11
The transfer paper 12 and ink film 10 are placed on top of the recording head, and the recording head is pressed against the platen 11 with a force 13 (Fl) as shown in the figure. In order to perform recording, the transfer paper 12 and the ink film IO are moved at a constant speed in the direction of an arrow 14. The angle 21 formed between the platen and the recording substrate is defined as θ2 in the figure, and θ2 is
By making the angle smaller than 1, good electrical connection can be achieved between the recording needle and the resistive layer. In this way, the tip of the recording needle is pressed against the resistance layer and a voltage is applied between adjacent recording needles to energize the resistance layer and generate heat.
The molten ink layer is melted and transferred to a receiving paper to form pixels. Conventional printing apparatuses have been constructed using the above recording method.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, an excessive current may suddenly occur between the recording needles, and this phenomenon causes excessive heat generation, causing damage to the resistive layer, support layer, or However, there is a problem in that both of these carbides adhere between the recording needles. The cause of this will be explained using FIG. 6. FIG. 6 is an enlarged cross-sectional view of the central portion of the recording needle in a state where the extreme light end portion of the recording head shown in FIG. 5 is in contact with the ink film. This figure shows the state of deformation 52 of the ink film caused by the recording needle 5 and the recording substrate 6. 0 The electrical connectivity of the current-carrying part 50 is good, but the current flowing is unstable due to the current-carrying state of the current-carrying part 51 above the current-carrying part 50. It changes depending on. Although no special problem occurs during normal operation, abnormal contact due to dust, vibration, etc., or large surface irregularities of the ink film, etc., generate abnormal current from the unstable current-carrying portion, causing the above-mentioned problem. The present invention is intended to solve these problems, and its purpose is to provide a highly reliable printing device that ensures stability in current supply.

[Means for Solving the Problems] The printing device of the present invention uses an ink film having a resistive layer and a melting ink layer, and has a recording head consisting of a plurality of recording needles and a recording substrate having the recording needles on one surface. by bringing the recording needle into contact with the resistance layer and applying a voltage between the adjacent recording needles to energize the resistance layer and generate heat;
In a printing device that performs recording by melting the molten ink layer and transferring it to transfer paper to form pixels, the material of the recording needle is tungsten, and the surface of the recording needle is oxidized. It is characterized by

[Embodiment] FIG. 1 is a sectional view of the tip of a recording head in an embodiment of the present invention. This embodiment is similar to the conventional example in that the recording needle 5 is formed on the recording substrate 6, but in this embodiment, the surface of the recording needle is covered with an electrically insulating layer 40. The material of the recording needle was tungsten, which was oxidized to form a tungsten oxide surface to form an insulating layer. FIG. 2 shows an enlarged cross-sectional view of the central portion of the recording needle in a state where the extreme light end portion and the ink film are in contact with each other when the recording head of FIG. 1 according to the present embodiment is used. FIG. 2 is a diagram corresponding to FIG. 6 of the conventional example. The state of deformation 52 of the ink film due to the recording needle and the recording substrate is excluded. The end face of the tip of the recording needle 5 is polished to secure the current-carrying part 50. Because of the presence of the insulating layer 40, there is no unstable current-carrying part as in the conventional example, and the structure is such that current can always flow and stably conduct electricity only in the current-carrying part 50.

In the conventional technology, an excessive current may suddenly occur between the recording needles, and this phenomenon causes excessive heat generation, resulting in the problem that carbides of the resistive layer, the support layer, or both adhere to the space between the recording needles. It had On the other hand, when recording was performed with a printing apparatus using the recording head of the embodiment of the present invention, the above-mentioned problem did not occur at all, and stable current recording could be performed at all times.

[Effects] The present invention uses tungsten as the material of the recording needle and further oxidizes its surface to prevent the adhesion of foreign matter between the recording needles due to sudden overcurrent, which was a drawback of the current-carrying thermal transfer recording method. This problem was solved by insulating the problem, and a printing device with revolutionary reliability was realized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the tip of a recording head in an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the central portion of the recording needle in a state where the extreme light end portion of the recording head and the ink film are in contact with each other in the embodiment of the present invention. FIG. 3 is a cross-sectional view of the structure of an ink film for electrically conductive thermal transfer recording. FIG. 4 is a diagram showing a recording section of a recording head of a conventional current-carrying thermal transfer recording system. FIG. 5 is a diagram showing a method of arranging and pressing a recording head and a platen. FIG. 6 is an enlarged view of a cross section at the center of a recording needle in a state where the extreme light end portion of a conventional recording head is in contact with an ink film.9 Melting ink layer 11.1 Resistive layer 19.3 Transfer paper , 12, Ink film , , 10, Recording substrate 00.6, Recording needle 00.5, Recording head 06.4, Insulating layer , 40 or more

Claims (1)

[Claims] Using an ink film having a resistive layer and a melting ink layer,
Using a recording head consisting of a plurality of recording needles and a recording substrate with the recording needles on one surface, the recording needles are brought into contact with the resistance layer, and a voltage is applied between the adjacent recording needles to increase the resistance. In a printing device that performs recording by applying electricity to a layer to generate heat to melt the melted ink layer and transfer it to transfer paper to form pixels, the material of the recording needle is tungsten, and the material of the recording needle is tungsten. A printing device characterized by an oxidized surface.