JP2773196B2 - Print recording head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print recording head used for a current transfer recording method.

2. Description of the Related Art Hitherto, an energization recording method has been proposed as a print recording method for forming an image by converting an image electric signal into thermal energy, dissolving an ink layer with the thermal energy, and transferring the image to transfer paper. .

As shown in FIG. 3, as a print recording head used in such a recording method, a return electrode 5 having a larger contact area than the recording electrode 2 is provided integrally, and the recording electrode and the return electrode are integrated. Print recording head (see, for example, JP-A-59-171666) or
As shown in the drawing, there has been proposed a print recording head or the like in which a recording electrode 2 composed of a patterned metal layer and an insulating film 6 are laminated on a plate-like rigid body 7.

Problems to be Solved by the Invention In the former print recording head, since the recording electrode and the return electrode are present on the contact surface with the print recording medium, the press contact area of the print recording head increases, and it is necessary to increase the total pressing pressure. However, there is a problem that uniform pressure contact is difficult to be performed, and a torque of a driving roll is increased. As a result, reliability of print recording is impaired.

In the latter print recording head, it is necessary to bring the head end face into surface contact with the print recording medium when recording an image. Therefore, if the print recording head is tilted with respect to the print recording medium, the contact ratio becomes extremely poor. Therefore, the print recording head must be always held vertically, and a high-precision head holding mechanism is required. .

The present invention has been made in view of the above problems.

That is, an object of the present invention is to provide high reliability of electrical contact between an electrode portion and an ink medium, enable sufficient contact with a small pressing force, reduce abrasion with an ink recording medium, and prevent long-term use. To provide a possible print recording head.

Means for Solving the Problems The present inventors have proposed a print recording head which has solved the above-mentioned conventional problems by first providing a conductive protrusion near the tip of a recording electrode provided on a substrate of the print recording head. However, as a result of further study, it was found that if the tip of the recording electrode was not exposed at the leading edge of the print recording head, the durability would be further improved, and the present invention was completed.

That is, the print recording head of the present invention has a structure in which a plurality of recording electrodes are arranged in parallel on a substrate and covered with an insulating film except for the tips of the plurality of recording electrodes. A print recording head formed by forming a protrusion made of a conductive material on a tip not covered with the recording material, wherein the protrusion is located closer to the head tip than the tip of the recording electrode. .

In the print recording head of the present invention, the substrate on which the recording electrodes are provided preferably has an elastic layer.

In the print recording head of the present invention, the protrusion made of a conductive substance is preferably provided to protrude from the insulating film by 1 to 200 μm, more preferably to protrude by 5 to 50 μm, thereby further improving the contact stability. Is done.

The protrusion made of a conductive substance may have any shape, for example, a shape having a square, rectangular, circular, or elliptical shape. Further, it is preferable to provide a high melting point metal or a conductive ceramic as a wear-resistant layer on the protrusion made of a conductive substance in order to prevent abrasion.

Action The print recording head of the present invention is used when a recorded image is obtained by a current transfer recording method or an electrostatic recording method. For example, in the energization transfer recording method, a print recording head is pressed against an ink recording medium having a heating element layer and a heat-meltable ink layer, and a plurality of recording electrodes of the print recording head slide on the ink recording medium. Contact. An image electric signal from the print recording head is input to the heating element layer, Joule heat is generated in the heating element layer, the adjacent ink layer is melted according to the image shape, and the ink is transferred to a transfer material (generally paper). The layers are transferred and recording is performed.

In the present invention, as described above, the tip of the protrusion is
Since the recording electrode is located closer to the head tip than the tip of the recording electrode, the print recording electrode is not exposed even if the print recording head is worn due to sliding friction. Therefore, two-point contact between the protruding portion and the recording electrode does not occur due to abrasion, and there is no increase in the energized area, so that the resistance value does not decrease.

In the print recording head of the present invention, when the substrate is made of an elastic material, the print recording head is deformed correspondingly even if there are irregularities or undulations on the surface of the print recording medium. Therefore, the protruding portion provided at the tip of the recording electrode acts so as to always maintain a stable contact state.

Examples Hereinafter, the present invention will be described in detail with reference to examples shown in the drawings.

FIGS. 1A and 1B show a print recording head according to an embodiment of the present invention, wherein FIG. 1A is a transverse sectional view, FIG. 1B is a longitudinal sectional view, and FIG. A plurality of recording electrodes 2 formed in a pattern are arranged in parallel on a substrate 1, and the recording electrodes are covered with an insulating film 3 except for a tip portion thereof. Projected portions 4 (4a, 4b, 4c, 4d) are formed on exposed portions of the recording electrode that are not covered by the insulating film. Further, each recording electrode is disposed so that the tip thereof is located at a distance d from the tip edge of the print recording head, and therefore, is located between the tip of the recording electrode and the tip edge of the print recording head. The insulating film is interposed. In the present invention, the distance from the tip end edge of the print recording head to the tip of the protruding portion is preferably 10 μm to 70 μm, and the tip of the recording electrode may be in contact with the protruding portion.

As the substrate 1, insulating ceramic, plastic,
A rigid substrate made of metal or the like coated with insulation is used.
An elastic layer on a rigid substrate, a layer of silicone rubber, urethane rubber, synthetic rubber, natural rubber, porous material, foamable material, etc. laminated thereon, and furthermore polyimide, polyester, other heat resistant plastics What laminated | stacked the insulating film etc. can be used.

On the substrate, a plurality of recording electrodes are formed in parallel in a strip shape. For example, conductive metals (Ni, Cr, Au, Cu, Ta, Ti, Fe,
Al, W, Zn, Sn, Pt, Pb and alloys containing them) are deposited to a thickness of 0.2 to 50 μm by vacuum evaporation, sputtering, electroless plating, electrolytic plating, etc., and then formed The metal film thus formed can be formed into a stripe pattern by a combination of lithography using light or laser and wet etching, or a combination of dry etching.

The formed recording electrodes are then covered by providing an insulating film. In this case, a part including the tip of each recording electrode is covered so as to be exposed. For example, a photosensitive insulating film (dry film) is thermocompression-bonded, and is removed by photolithography and wet etching in order to expose a portion of the recording electrode corresponding to a portion in contact with the print recording medium. Alternatively, the recording electrode may be exposed by thermocompression bonding of the insulating film without using the photosensitive insulating film, using a resist film, and combining photolithography and dry etching. The thickness of the insulating film is preferably in the range of 5 to 50 μm. Further, the portion of the recording electrode not covered with the insulating film, that is, the shape and size of the exposed portion may be any shape as long as it does not contact the adjacent recording electrode,
The shape is preferably a square or a circle, and the size is
It is preferable that the width is about the electrode width.

A projection made of a conductive material is formed on the exposed portion formed on the recording electrode. For example, conductive metals (Ni,
(Cr, Cu, etc.) is adhered to the exposed portion on the recording electrode by electrolytic plating so as to be thicker than the insulating film, thereby forming a protrusion.

It is preferable that the protrusion is provided so as to protrude from the insulating film by 0.5 to 200 μm, particularly 5 to 50 μm. 0.5 protrusion
If it is smaller than μm, there is little difference in effect from a print recording head having no protrusion. On the other hand, if the height is higher than 200 μm, the protruding portion is easily broken, and it is difficult to manufacture the protruding portion so as not to contact the adjacent protruding portion.

In the present invention, it is preferable to provide a wear-resistant layer such as a refractory metal or a conductive ceramic on the surface of the protrusion.

In the drawings, the protruding portions of the recording electrodes are formed in a line in a direction parallel to the contact surface, but may be in a staggered state, for example.
One or more pieces may be arranged in a sawtooth shape.

Next, a more specific example of the print recording head of the present invention will be described.

An example of a substrate in which an elastic layer and an insulating film are laminated on an aluminum plate will be described.

First, a polyimide film was used as an insulating film, and Cu was vacuum-deposited thereon to a thickness of 1 μm, and the width was 50 μm by lithography and wet etching.
Recording electrodes were formed in a stripe shape with a pitch of 125 μm.
10 μm on the insulating film on which this recording electrode is formed
Thermocompression bonding of a photosensitive film (dry film) with a thickness of
A 70 μm × 70 μm square exposed portion was provided at the tip of the recording electrode by photolithography and wet etching. Ni was protruded from the dry film by 12 μm from the dry film at the exposed portion by electroplating to provide a protruding portion. The wiring board based on the formed insulating film is bonded with a silicone rubber plate (rubber hardness 50, thickness 1 mm) and an aluminum plate (thickness 3 mm) with an epoxy-based thermosetting adhesive,
Cut with a dicing saw so that the protrusion is located at a distance of 50 μm from the leading edge of the print recording head,
A print recording head was created.

The printed print head thus prepared was tested as shown in FIG. That is, surface resistance 600Ω / □, thickness 20μ
A conductive polyimide film 11 having a thickness of 2000 mm and an aluminum film 12 having a thickness of 2,000 mm are wound around an aluminum drum 9 having a diameter of 100 μm with the deposited surface inward. Pressure 500g / cm,
The contact between the recording electrode and the aluminum drum was measured while the aluminum drum was rotated while being pressed against at a contact angle θ = 30 °, and how the change in the resistance changed with the cumulative number of rotations was examined.

For comparison, a test was performed in the same manner using the same print recording head as in the above example, except that the recording electrode extended to the leading edge of the print recording head as shown in FIG.

The results obtained are shown in Table 1 below. The values in the table indicate the ratio of the electrodes having a resistance change rate of ± 50% or more with respect to the initial resistance value.

As is clear from the above results, the print recording head of the present invention has better durability than the comparative example.

According to the print recording head of the present invention, since the tip of the protrusion formed on a part of the recording electrode is closer to the tip of the head than the tip of the recording electrode, only the protrusion is a print recording medium. As a result, the contact portion is controlled in area. Therefore, the contact pressure of the entire print recording head can be reduced. Furthermore, since the front end of the recording electrode and the front end edge of the print recording head are separated by the insulating film as described above, the print recording electrode is exposed even when the print recording head is worn by sliding friction. Never do. Therefore, two-point contact between the protruding portion and the recording electrode does not occur due to abrasion, and since there is no increase in the energized area, the resistance value does not decrease. Become.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a print recording head according to the present invention, in which (a) is a transverse sectional view, (b) is a longitudinal sectional view, (c) is a perspective view, and FIG. FIG. 3 is a longitudinal sectional view of a print recording head of a comparative example, FIGS. 3 and 4 are perspective views of a conventional print recording head, and FIG. 5 is an explanatory diagram for explaining a test method of the print recording head. . 1 ... substrate, 2 ... recording electrode, 3 ... insulating film, 4 ...
... projecting part, 5 ... return electrode, 6 ... plate-like rigid body, 7 ... insulating film, 8 ... print recording head, 9 ... aluminum drum, 10 ... weight, 11 ... conductive polyimide film, 12 ... Aluminum film.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-178359 (JP, A) JP-A-63-286360 (JP, A) Real opening Sho-61-1998035 (JP, U) (58) Investigation Field (Int.Cl. ⁶ , DB name) B41J 2/32-2/325

Claims (4)

(57) [Claims] 1. A plurality of recording electrodes are arranged in parallel on a substrate, covered with an insulating film except for the tips of the plurality of recording electrodes, and are not covered with the insulating film of the recording electrodes. What is claimed is: 1. A print recording head comprising a projecting portion made of a conductive substance at a tip portion, wherein the tip portion of the projecting portion is closer to the tip of the recording electrode than the tip of the recording electrode. head. 2. The print recording head according to claim 1, wherein the protrusion is provided so as to protrude from the insulating film by 1 to 200 μm. 3. The print recording head according to claim 1, wherein the protrusion is covered with a wear-resistant layer made of a high melting point metal or a conductive ceramic. 4. The print recording head according to claim 1, wherein the substrate has an elastic layer.