JPH03197152A - Manufacture of electrostatic recording head - Google Patents

Abstract

PURPOSE:To prevent warpage of an electrode board and crack of molding resin upon shrinkage of the resin and to prevent manufacturing yield by securing an outer frame member so formed as to form an air gap to the electrode at both sides of the electrode formed with recording electrode, pouring and curing the resin in the gap between the electrode and the member. CONSTITUTION:An outer frame member 2 is secured to an electrode 1 to hold the electrode 1 at both sides thereby to be secured. A lateral groove 3 is formed at a recording side of the end of the member 2. Accordingly, when the electrode 1 is held by the member 2, an air gap 4 is formed between the members 2 and an electrode 12. The electrode 1 is held fixedly by the members 2, electrode burying molding resin 5 is poured in the gap 4 to be cured. Since the quantity of the used resin 5 is extremely less and the shrinkage of the resin 5 is small, the resin which has excellent voltage resistance, tracking resistance, electric corrosion resistance such as arc resistance, further heat resistance, wear resistance and low thermal expansion coefficient may be selected. As the resin 5, epoxy resin is suitable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an electrostatic recording head used in an electrostatic recording device.

[Conventional technology]

FIG. 7 is a perspective view of a conventional electrostatic recording head, and FIG. 8 is an enlarged view of the recording sliding surface at the tip of the electrostatic recording head. The electrode section of the electrostatic recording head shown in FIGS. 7 and 8 includes a substrate 50 and a large number of recording electrodes 51 formed on the substrate 50. Recording electrodes 51 provided on both sides of the substrate 50 are for applying an electrostatic pattern to the recording paper. Recording electrode 5 shown in FIGS. 7 and 8
Reference numeral 1 denotes a pattern electrode obtained by etching a metal film formed on a substrate 50 into a predetermined pattern.

A conventional method for manufacturing an electrostatic recording head involves inserting the tip of a substrate 50 on which a recording electrode 51 is formed into a mold 55 shown in FIG. 9, and injecting a casting resin 52 around it and hardening it. An electrostatic recording head is obtained. A casting resin 52 surrounding the electrode portion is provided to protect the recording electrode 51 and the substrate 50 that come into sliding contact with the recording paper.

[Problem to be solved by the invention]

By the way, in the conventional method of manufacturing an electrostatic recording head, the seventh
As shown in the figure, a large amount of casting resin 52 is used to protect the substrate 50 and recording electrodes 5I. This resin 52 has the property of shrinking and deforming during the process of changing from a semi-fluid state at the time of injection to a solid state through a curing process. When such contraction occurs, a very large force is applied to the electrode portion, which may cause warping. Further, even if the straightness of the substrate 50 is slightly impaired due to this warping, the quality of the recorded image is degraded. Particularly, when manufacturing an electrostatic recording head having a long width H of, for example, 90 cm, this is a problem because warping is likely to occur due to shrinkage of the casting resin 52.

In addition, in the conventional manufacturing method, cracks may occur in the casting resin 52 itself due to shrinkage of the casting resin 52, or cracks may occur in the casting resin 52 itself.
2 and the substrate 50 may peel off. With the casting resin 52 peeled off from the substrate 50 in this way, the recording electrode 51
If voltage continues to be applied for a long period of time, there is a risk that the recording electrode 51 will be electrically eroded and a short circuit will occur between the electrodes.

Furthermore, such contraction of the casting resin 52 causes the recording electrode 5 to
1 or cause a dimensional deviation between the electrodes. Moreover, since such defects are discovered after the entire substrate 50 is covered with the casting resin 52 and cured, the entire electrostatic recording head has to be discarded as a defective product, resulting in a low yield. There is a problem in that it leads to an increase in costs. Incidentally, some conventional electrostatic recording heads have wire electrodes 53 arranged at predetermined mutual positions as shown in FIG. 10 instead of the above-mentioned electrode section. Similar problems to those described above arise when manufacturing heads.

The present invention has been made based on the above circumstances, and provides an electrostatic recording head that can prevent warping of the electrode portion and cranking of the casting resin due to shrinkage of the casting resin, and can increase the yield in the manufacturing process. The purpose is to provide a manufacturing method.

[Means to solve the problem]

In order to achieve the above object, the method for manufacturing an electrostatic recording head according to the present invention is such that a recording electrode is formed on both sides of an electrode section on which a recording electrode is formed so that a gap is formed between the electrode section and the electrode section. The method is characterized by comprising a step of fixing an outer frame member, and a step of injecting a resin into the gap between the electrode portion and the outer frame member and curing the resin.

[Effect]

According to the method for manufacturing an electrostatic recording head according to the present invention, since both sides of the electrode section are sandwiched between the outer frame members, warping of the electrode section due to shrinkage of the resin can be prevented, and the outer frame Since resin only needs to be injected into the gap between the component and the electrode section, the amount of resin used is significantly smaller than in conventional manufacturing methods, and therefore the amount of shrinkage when the resin hardens is extremely small. Become.

〔Example〕

FIG. 1(a) is a perspective view of an outer frame member used in the method for manufacturing an electrostatic recording head according to the first embodiment of the present invention, and FIG. 1(b)
(C) is a cross-sectional view of a state in which the outer frame member is fixed to the electrode part, and (C) is a cross-sectional view of a state in which a casting resin is injected into the gap and cured.

In FIGS. 1(b) and (C), the electrode part l is approximately the same as the electrode part shown in FIG. Either by laminating thin films of metal such as copper, or by directly bonding thin copper to the substrate. This lol
4. Unnecessary portions of the thin film other than the electrode portions are removed by etching to form recording electrodes in a predetermined pattern. In addition, after surface polishing the substrates, in order to improve the recording density, the back sides of the two substrates on which recording electrodes were formed were placed between the recording electrodes on one substrate and the recording electrodes on the other substrate. Lay them together (in a staggered manner) so that the recording electrodes of the substrate are aligned.

By fixing the outer frame member 2 to the electrode part 1 thus obtained, the electrode part 1 is clamped and fixed from both sides by the outer frame member 2, as shown in FIG. 1(b). This outer frame member 2 is provided with a horizontal groove 3 in the recording sliding portion at the tip thereof, as shown in FIG. 2(a). Therefore, when the electrode part 1 is held between the outer frame member 2, a gap 4 is created between the outer frame member 2 and the electrode part l. There are no particular restrictions on the material that can be used for the outer frame member 2, as long as it does not cause an electrical short due to contact with the recording electrode and has sufficient rigidity, such as thermoplastic resin such as polyester resin, thermosetting resin, etc. , glass, ceramic, etc. can be used. However, since the surface of the outer frame member 2 that presses the electrode portion 1 directly affects the straightness of the electrode portion 1, it is necessary to perform surface polishing or the like to finish it into a good flat surface.

After clamping and fixing the electrode part 1 between the outer frame members 2, the electrode part 1 is shown in FIG.
), a casting resin 5 for embedding the electrode is injected into the gap 4 and hardened. Since a large amount of resin is used as the casting resin 5 in the conventional manufacturing method, it was necessary to select a resin with low stress during curing. For this reason, the electrical erosion resistance of the resin is not very good, and there is a problem that electrode damage occurs due to deterioration of the resin, and image quality deteriorates due to dropouts during drawing. However, in this example, as shown in FIG. 1(c), the amount of the casting resin 5 used is extremely small, and the shrinkage of the casting resin 5 is extremely small, so that good electrical corrosion resistance is achieved. The degree of freedom in using resin expands. Therefore, in this example, in order to protect the recording electrodes to which high voltage is applied, the casting resin has excellent electrical erosion resistance such as voltage resistance, tracking resistance, and arc resistance, as well as heat resistance and resistance. It is possible to select one that has resistance to thermal wear and a low coefficient of thermal expansion. From this point of view, the casting tree Rs.
Epoxy resin is suitable as a hardening agent, and amine, acid anhydride, imidazole, etc. are used as a hardening agent. In addition to epoxy resins, thermosetting resins such as polyimide can also be used.

Furthermore, since the manufacturing method of this embodiment uses a very small amount of epoxy resin, unlike conventional manufacturing methods, shrinkage during curing of the casting resin 5 can be suppressed to a small level.

Therefore, unnecessary force applied to the electrode part 1 can be suppressed to an extremely low level, and warping of the electrode part 1 can be suppressed, and cracks can be prevented from occurring in the casting resin 5 and the electrode part 1 and the casting resin 5 can be prevented from forming.
peeling can be prevented. As a result, deviations in the dimensions between the electrodes that occur due to these phenomena are reduced.

According to the above embodiment, the electrical erosion resistance is improved and the incidence of defects can be suppressed, so that the yield can be increased and the manufacturing cost can be reduced.

Moreover, according to this embodiment, after the electrode part 1 is sandwiched between both sides by the outer frame member 2 in advance, the casting resin 5 is injected and cured, so that the straightness of the electrode part 1 is improved more than in the conventional method. can be maintained.

FIG. 2(a) is a perspective view of an outer frame member 6 used in a method for manufacturing an electrostatic recording head according to a second embodiment of the present invention, and FIG.
) is a top plan view of the state in which the outer frame member is fixed to the electrode part, and FIG.

In this figure, the same components as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 2(a), the outer frame member 6 is provided with a large number of semi-cylindrical grooves 7 in the vertical direction. This groove 7 allows the casting resin 5 to be inserted between the outer frame member 6 and the electrode part 1 when the outer frame member 6 is fixed to the electrode part l in the same way as the groove 3 shown in FIG. In the manufacturing method of this embodiment as well, the casting resin 5 is injected with the electrode section 1 held between the outer frame members 6, and the amount of casting resin N5 used is very large. Since the amount of shrinkage is small, the various adverse effects caused by shrinkage when the casting resin 5 hardens are almost non-problematic, similar to the first embodiment.

FIG. 3(a) is a perspective view of an outer frame member 1° used in a method for manufacturing an electrostatic recording head according to a third embodiment of the present invention;
gJ(b) is a top plan view of the state in which the outer frame member 1° is fixed to the electrode part 1, and FIG. In the same figure, the first
Components that are the same as those shown in the figures and FIG.

In FIG. 3(a), the outer frame member 10 has a horizontal groove 11a at its tip, and a vertical semi-cylindrical groove 1 below it.
1b are provided in large numbers. Therefore, the voids 12a and 12b of this embodiment have a shape that combines both the void 4 shown in FIG. 1 and the void 8 shown in FIG. 2.

The outer frame member 2 shown in FIG. 1 can protect the entire tip of the recording electrode that comes into sliding contact with the recording paper with the casting resin 5, but on the other hand, the casting resin Bi5 cannot be injected into the lower part of the outer frame member 2. Although the outer frame member 6 shown in FIG. 2 allows the casting resin 5 to be widely injected into the part that contacts the electrode part 1, it cannot sufficiently protect the tip part of the head where the recording electrode is expected to be damaged the most. In the third embodiment, since the outer frame member is formed in the shape shown in FIG. 3(a), both of the drawbacks can be compensated for. In the case of the third embodiment as well, the amount of casting resin 5 used is sufficiently small, and almost no adverse effects occur due to shrinkage when the casting resin 5 hardens.

FIG. 4(a) is a perspective view of an outer frame member used in a method for manufacturing an electrostatic recording head according to a fourth embodiment of the present invention, and FIG.
) is a top plan view of the state in which the outer frame member is fixed to the electrode part, and FIG.

In this figure, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 4(a), two parallel grooves 15a and 16b are provided in the outer frame member 15 in the lateral direction. Also groove 1
6a is provided slightly below the tip of the outer frame member 15. After holding the electrode part 1 between the outer frame members 15 and injecting the casting member 5 into the gaps 17a and 17b between the electrode part 1 and the outer frame member 15 and curing it, the dotted line in FIG. 4(C) By removing the tips 15a-t of the outer frame member 15 and polishing the tips, the electrode portion 1 and the casting resin 5 are exposed at the tip of the head. Thereby, the straightness of the sliding portion (tip portion) of the electrostatic recording head against the recording paper can be reliably maintained.

In addition, as shown in FIG. 4(C), the recording electrode at the tip of the head can be protected by the casting resin 5 injected into the gap 17a, and at the same time, the recording electrode at the tip of the head can be protected from the outside by the casting resin 5 injected into the gap 7b. The frame member 15 and the electrode section 1 can be brought into close contact with each other. Other functions and effects are similar to those of the first embodiment.

FIG. 5(a) is a perspective view of an outer frame member used in a method for manufacturing an electrostatic recording head according to a fifth embodiment of the present invention, and FIG.
) is a top plan view of the state in which the outer frame member is fixed to the electrode part, and FIG.

In this figure, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

As shown in 5th rM(a), a cutting portion 21 is provided in the outer frame member 20 of this embodiment. The electrode part l is held between the tip part 20a of the outer frame member 20, and the casting resin 5 is injected into the gap 22 between the outer frame member 20 and the electrode part 1. Next, the casting resin 5 is hardened. After that, the tip 20a of the outer frame member 20 shown by the dotted line in FIG. 5(C) is removed and polished to expose the electrode part 1 and the casting resin 5 at the tip of the head. As a result, as in the fourth embodiment, the straightness of the sliding portion (tip end) of the electrostatic recording head against the recording paper can be reliably maintained.

In addition, as shown in FIG. 5(C), the recording electrode at the tip of the head can be protected by the casting resin 5 injected into the gap 22, and at the same time, the casting resin 5 can be brought into close contact with the electrode portion l. , the internal recording electrodes can also be protected from electrical erosion and the like. Other functions and effects are similar to those of the first embodiment.

Figure 6 shows the relationship between the volume of casting resin injected into the gap provided between the electrode part and the outer frame member and the proportion of defects and defects that occur in the electrode part due to warping, peeling, etc. after the casting resin has hardened. This is a graph obtained experimentally.

As can be seen from the figure, as the volume of the injected casting resin increases, the number of defects and defects occurring in the head increases rapidly. The conventional manufacturing method for electrostatic recording heads corresponds to the right side of the graph in FIG. 6, so defects and defects often occur, but each embodiment of the present invention can reduce the amount of casting resin used. Although there are some differences, the amounts are much smaller than in conventional electrostatic recording heads, and the proportion of defects and defects that occur in electrostatic recording heads can be significantly reduced.

In addition, in the above embodiment, a case was explained in which patterned electrodes were used as recording electrodes in the electrode section, but the recording electrodes in the recording section may also be wire electrodes, and in the above embodiment, two electrodes were used. We have explained the case where the electrode section is manufactured by forming recording electrodes on one side of each substrate and then bonding two substrates together. You may also do so.

〔Effect of the invention〕

As explained above, according to the present invention, after the electrode part is clamped between the outer frame members in advance, the resin is injected and cured, and the amount of resin used can be reduced in comparison with the conventional method. Accordingly, it is possible to provide a method for manufacturing an electrostatic recording head that can prevent warping of the electrode portion and cranking of the resin due to resin contraction, and can increase the yield in the manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a method for manufacturing an electrostatic recording head, which is a first embodiment of the present invention, and FIG. 2 is a diagram for explaining a method for manufacturing an electrostatic recording head, which is a second embodiment of the present invention. FIG. 3 is a diagram for explaining a method for manufacturing an electrostatic recording head according to a third embodiment of the present invention, and FIG. 4 is a diagram for explaining a method for manufacturing an electrostatic recording head according to a fourth embodiment of the present invention. Figure 5 is a diagram for explaining the method for manufacturing an electrostatic recording head according to the fifth embodiment of the present invention. Figure 6 is a diagram showing the volume of casting resin and the defective rate occurring in the head. Graph showing the relationship between
9 to 9 are diagrams for explaining a method of manufacturing a conventional electrostatic recording head, and FIG. 10 is an enlarged view of the recording sliding surface at the tip of another conventional electrostatic recording head. ■... Electrode part, 2.6.10, 15.20... Outer frame member, 3.7, 1
1.16...Groove, 4.8, 12, 17.22...Gap, 5...Casting resin, 21...Cutting part.

Claims (1)

[Claims] a step of fixing outer frame members formed so as to form a gap between the electrode section and the electrode section on both sides of the electrode section on which the recording electrode is formed, and the gap between the electrode section and the outer frame member; A method for manufacturing an electrostatic recording head, comprising the steps of: injecting a resin into the liquid and curing the resin.