JP2890824B2 - Energized recording head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a recording head used in an energization transfer recording system that enables non-impact printing. More specifically, the present invention relates to a recording head that selectively supplies a current to a thermal transfer recording medium having a resistance layer and an ink layer to locally generate heat, and transfers the ink layer to a transfer member in an image form to perform printing.

(Prior Art) As a method for recording an image on a transfer member according to an electric signal, a thermal transfer recording medium having a resistive layer and an ink layer is selectively applied from a current-carrying recording head to a resistive layer of the thermal transfer recording medium according to an electric signal. A method is known in which a current is supplied to a transfer member to cause the resist layer to generate heat by Joule heat to melt the ink and transfer the ink layer to a transfer member in an image-like manner, so-called energized transfer recording. In such a method, in order to obtain high-quality printing, the contact area and contact pressure between the recording electrode to be energized and the recording medium are kept constant, the resistance value and contact state of the contact portion are kept constant, and the resistance layer is used. It is important to stabilize the amount of heat generated. As a prior art for solving such a problem, Japanese Patent Application Laid-Open Nos.
A method disclosed in JP-A-3-286360 is known. That is, in these methods, the pressure of the head is concentrated on the recording electrodes by forming the recording electrodes higher than the insulating layer that insulates adjacent recording electrodes from each other, and the recording electrodes to be energized and the recording medium are energized. This has the effect of stabilizing contact with the body.

(Problems to be Solved by the Invention) However, in the conventional energized recording head, the recording electrodes at both ends of the recording electrode row do not have adjacent recording electrodes on one side. There is a disadvantage that the pressure becomes larger than the pressure generated between the recording electrodes and the ink medium, and the dots printed by the recording electrodes at both ends become larger than the dots printed by the other recording electrodes. Further, since the recording electrodes at both ends come into contact with the thermal transfer recording medium with a larger pressure than the other electrodes, the wear of the recording electrodes is increased, and even if the other recording electrodes are still in a usable state because the wear of the recording electrodes is still small, the recording electrodes at both ends are usable. There is a disadvantage that the recording electrode becomes unusable and the life of the entire head is shortened.

An object of the present invention is to improve the above-mentioned problems of the related art.

(Means for Solving the Problems) In order to solve the above problems, in the energized recording head of the present invention, the tips of a plurality of recording electrode wires formed in a row and covered with an insulating member are exposed, and the tips thereof are exposed. In a current-carrying recording head in which a recording electrode protruding from an insulating member is formed in a portion, a protruding portion having substantially the same height as the protruding recording electrode is formed outside the protruding recording electrode row. The shape of the protruding portion may be the same shape as the protruding recording electrode or may be a different shape. The material may be the same material as the protruding recording electrode, or may be a different material. Further, the protruding recording electrode and the protruding portion may be formed separately, or may be formed simultaneously using the same material. When the same material is used for simultaneous formation, it is easy to use a plating method. In this case, the protruding portion is formed in the same manner as the recording electrode itself, in a form in which the number of recording electrodes is increased, and without wiring the electrode lines for printing, the protruding portion is formed as a dummy electrode that is not printed. Is also good.

(Operation) Since a projection having the same height as the recording electrode is provided outside the recording electrode, the pressure applied to the recording electrode is dispersed at the projection.
The pressure becomes the same as that of the other protruding recording electrodes, so that the dots printed by the protruding recording electrodes at the end portions do not become large or wear does not increase.

Hereinafter, a specific embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an example of the structure of a current-carrying recording head according to the present invention. FIG. 2 is a sectional view of a portion A and B in FIG.
This is shown in the figure and FIG. An electrode wire 2 is formed in parallel on a flexible insulating support 1, and an insulating layer 3 is further formed thereon. The insulating layer 3 helps to prevent a short circuit and discharge between the adjacent recording electrodes 4. The insulating layer 3 on the tip of the electrode wire 2 is removed, and a protruding recording electrode 4 that comes into contact with the electrode wire 2 and a projection 5 at the end are provided. Endmost protrusion 5
May not be in contact with the electrode wire 2. The recording section of the current-carrying recording head of the present invention can be formed by attaching the protruding recording electrode 4 produced by the above process and the insulating support 1 having the protruding portion 5 to the substrate 7 via the elastic body 6. . The protruding recording electrode 4 comes into contact with the resistance layer of the thermal transfer recording medium, and energizes the resistance layer of the thermal transfer recording medium according to an electric signal from the electrode wire 2. The elastic body 6 is made of an elastic material such as rubber, and is deformed so that each protruding recording electrode 4 contacts and follows irregularities on the surface of the thermal transfer recording medium.
And a thermal transfer recording medium. The substrate 7 is made of a rigid material such as metal or plastic, and serves to apply pressure when the current-carrying recording head comes into contact with the thermal transfer recording medium. The protrusion amount of the recording electrode from the insulating material is 1 μm to 200 μm.
μm is preferable, and 5 μm to 60 μm is more preferable.
10 μm to 30 μm are preferred.

Next, a method for forming the protruding recording electrode 4 and the protruding portion 5 will be described in detail. A metal foil is adhered on an insulating support such as a flexible film, or a metal layer is formed on the entire surface by vacuum evaporation or sputtering of metal, and then photolithography and wet etching, dry etching, laser drawing, or discharging are performed. The metal layer is patterned by drawing or the like to form parallel electrode lines 2. After an insulating layer is provided on the entire surface, the insulating layer at the tip of the electrode wire 2 is removed to expose the tip of the electrode wire 2.
As a method of removing the insulating layer, after forming the insulating layer on the entire surface, applying a photosensitive resin, exposing and developing in a pattern shape to remove the photosensitive resin at the tip portion, dissolving only the lower insulating layer For example, there is a method of removing the insulating layer by wet etching or dry etching using a liquid to be removed, and thereafter removing all the photosensitive resin. As a method of forming the protruding recording electrode, there is a method of forming a metal by electroplating or electroless plating. Metals are hard metals (Mo,
W, Ru, Rh, Re, Ta, Ti, Zr, etc.)
μm fine particles (Al ₂ O ₃ , BN, SiC, B ₄ C, NiO, Cr ₂ O ₃ , Si _{3
N 4, TiC, TiO 2,} WC, WSi 2, ZrO 2, ZrB 2, ZrC, C r3 C 2, T
aC, MgO, CaO, ThO _2, etc.) is a metal or conductive ceramics is mixed preferred. Alternatively, after substantially forming the electrode shape by metal plating, the above materials may be laminated and plated as a wear-resistant layer.

As a method of forming the protruding portion 5 having substantially the same height as the protruding recording electrode 4 outside the protruding recording electrode row, the protruding portion 5 is formed simultaneously when the protruding recording electrode 4 is formed by plating. can do. Alternatively, the recording electrode and the dummy electrode can be separately formed by, for example, previously forming an insulating resin having the same height as that of the protruding recording electrode 4 in the shape of the dummy electrode. In order to make the contact state of the electrode 4 whose end portion is in contact with the thermal transfer recording medium substantially the same as that of the other protruding recording electrodes, the shape of the protruding portion 5 is made the same as that of the protruding recording electrode, and the protruding recording electrode array Is preferably formed at a position corresponding to the above arrangement. Further, in order to make the abrasion of the protruding portion 5 the same as that of the protruding recording electrode 4, it is preferable that the material of the protruding portion 5 has the same hardness as that of the protruding recording electrode. It is preferred that Further, in the case of the conventional electrode as shown in FIG. 8, not only the recording electrode 16a at the end but also the inner recording electrode 16b, a little abrasion occurs although not as much as the recording electrode 16a at the end. Recording electrodes 16c and 16d
In this case, since little wear occurs, it is preferable to provide two or more, preferably four or more protrusions on one side. The arrows in FIG. 8 schematically show the magnitude of the pressure applied to each recording electrode. FIG. 4 shows an example of a current-carrying recording head having a plurality of protrusions 5 formed in the same shape and the same material as the protruding recording electrodes 4a and 4b. With such a configuration, there is almost no difference in the degree of wear between the protruding recording electrode 4a at the end and the protruding recording electrode 4b inside thereof, and a good recorded image can be obtained for a long time. To eliminate the difference in the degree of wear between the protruding recording electrodes inside the protruding recording electrodes at the ends,
It is also effective to make the shape of the protruding portion 5 larger than the protruding recording electrode 4 as shown in FIG. Arrows in FIG. 4 and FIG. 5 schematically show the magnitude of the pressure applied to each recording electrode.

(Examples) Specific examples and evaluation results are shown below. An energization recording head similar to the example shown in FIG. 4 was prepared as follows. A 10μm thick copper foil is adhered on a 20μm thick polyimide film, patterned by photolithography and wet etching, pitch 125μm and width 80μm
Was formed. At this time, in order to form a protruding portion outside the electrode wires at both ends used for printing, a total of eight electrode wires were formed on each side, each having a pitch of 125 μm and a width of 80 μm, similarly to the electrode wires used for printing. A 10 μm-thick layer of photosensitive polyimide was applied thereon, and exposed and developed to form a window at the tip of the electrode wire from which the 60 μm square photosensitive polyimide was removed. Ni was formed on the window by electroplating so as to be higher than the photosensitive resin by 10 μm, and a layer made of Ni mixed with 1 μm diameter SiC was formed by electroless plating as a wear-resistant layer. The wiring board prepared by the above method was cut at a position of 20 μm from the protruding recording electrode row, and bonded to a substrate to which a 2 μm-thick silicon rubber was bonded by aligning the edges of the wiring board and the substrate, thereby obtaining an energized recording head. . Printing was performed by the apparatus shown in FIG. The thermal transfer medium 8 and the transfer material 11 are overlapped between the energized recording head 9 and the pressure roll 10, and a voltage pulse is applied between the electrode line 2 of the energized recording head 9 and the return electrode 12 to remove the ink on the thermal transfer medium 8. Transfer to the transfer material 11. The contact pressure of the energizing recording head 9 is 300 gf / cm, and the printing pulse voltage is
At 12 V, the pulse width was 1.0 ms, and the printing speed was 50 mm / s. As the thermal transfer recording medium 8, a conductive layer 14 is formed on the resistance layer 13 of the carbon dispersion type polycarbonate film shown in FIG.
Al is deposited at a thickness of 0.1 μm, and an ink layer 1 is formed at a thickness of 4 μm.
5 was used.

The evaluation results are shown in FIGS. 9 and 10. FIG. 9 shows the size of the initial print dot, and FIG.
This is the state of wear of the protruding recording electrode after sliding for 1 km.
As is clear from these figures, the sizes of the dots of all the electrodes were the same, and the wear amount was uniform. The same result was obtained when the number of protrusions was two or one on one side.

(Comparative Example) As a comparative example, a head similar to that of the above-described example was prepared except that the protrusion was not provided, and the same test as that of the above-described example was performed and compared. FIG. 11 shows the size of the initial print dot. No.
FIG. 12 shows the worn state of the protruding recording electrode after sliding the thermal transfer recording medium for 1 km. Unlike the above-described embodiment, a change in dot size and wear of the recording electrode are observed.

(Effects of the Invention) As described above, according to the present invention, a protrusion having a height substantially equal to the height of a recording electrode protruding outside a protruding recording electrode row formed in a row is formed. Since the protruding recording electrodes also come into contact with the thermal transfer recording medium at the same pressure as the other protruding recording electrodes, the size and density of the dots printed by the protruding recording electrodes at both ends are different from those of the other protruding recording electrodes. The size and density are the same, and high-quality printing with uniform dot size and density can be performed. Furthermore, it is possible to prevent the recording electrodes at both ends from being worn faster than other recording electrodes,
The recording head has a long life.

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of a current-carrying recording head according to the present invention. FIG. 2 is a cross-sectional view (along the recording electrode row) of the energized recording head of the present invention shown in FIG. FIG. 3 is a cross-sectional view (along the electrode line) of the current-carrying recording head of the present invention shown in FIG. FIGS. 4 and 5 are schematic views showing a contact state between another example of the energized recording head of the present invention and the thermal transfer recording medium. FIG. 6 is a schematic diagram showing an outline of a printing apparatus used for evaluating the energized recording head. FIG. 7 is a schematic diagram showing the structure of the ink medium used for evaluating the energized recording head. FIG. 8 is a schematic diagram showing an example of a conventional energized recording head and a contact state of a thermal transfer recording medium. FIG. 9 is a graph of the dot diameter by the energizing recording head of the present invention.
FIG. 10 is a graph showing the state of wear of the electrodes of the current-carrying recording head of the present invention. FIG. 11 is a graph of the dot diameter of a conventional energized recording head. FIG. 12 is a graph showing the state of wear of a conventional energized recording head. DESCRIPTION OF SYMBOLS 1 ... Insulating support, 2 ... Electrode wire, 3 ... Insulating layer, 4, 4a, 4b
... projecting recording electrode, 5 ... projecting part, 6 ... elastic body, 7 ... substrate, 8 ... thermal transfer recording medium, 9 ... energizing recording head, 10 ... pressure roll, 11 ... transfer medium, 12 ... return electrode, 13 ... resistance layer,
14: conductive layer, 15: ink layer, 16a, 16b, 16c, 16d: protruding recording electrodes.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/32-2/325

Claims (1)

(57) [Claims] In a current-carrying recording head, a plurality of recording electrode wires formed in a row and covered with an insulating layer are exposed at their tips, and the exposed portions are provided with recording electrodes protruding from the insulating member. A current-carrying recording head, wherein a protruding portion which is substantially the same height as the protruding electrode and is not used for printing is formed outside the recording electrode row.