JPS6123403Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to plated typefaces used in typewriters, printers, and the like. Conventionally, typefaces used in the static impact type are broadly classified into pallet type, cylindrical type, petal type (see Japanese Patent Application Laid-open No. 37725/1983), and so on. In particular, in recent years petal type typefaces have been widely used as matrix typefaces due to their mechanical simplicity, and various designs have been devised to reduce inertia, cost reduction, and improve performance characteristics (Japanese Patent Application No. 51-25260). , Utility Application No. 166695, etc.). Methods for constructing typefaces include integral molding of the same material, glazing on only the typeface to prolong its lifespan, and methods of molding the typeface from different materials. The main materials for such construction are mostly plastics, including two types of reinforced plastics: thermoplastic nylon-based and polyacetal-based. However, in terms of impact strength, the inclusion of fibers usually results in a decrease in impact resistance and weakens the weld line portion. This is related to fiber orientation, adhesion to the resin, and differences in shrinkage rate. In other words, when reinforced with glass fibers, the strength increases in the direction in which the fibers flow, but not so much in the direction perpendicular to the flow. As a result, the type surface is subject to considerable wear due to deformation and cracking of the characters. Therefore, when a matrix type type is formed, the life of the type will vary greatly, with the fiber orientation resulting in very weak type. Therefore, in order to improve the strength of the typeface, phenolic resin, epoxy resin, polycarbonate,
Thermosetting resins such as polysulfone, polyamides, polyacetals, polyamide emides,
Some methods include adding carbon fibers or glass fibers to thermoplastic plastics such as olefin vinyl alcohol-based GL resins, or applying plating. However, in the former case, manufacturing costs are high because it cannot be integrally molded. In the latter case, the fibers protrude due to the influence of the strength of the material, which is thought to be due to the relaxation of internal stress in the resin surface layer due to fiber orientation, plating pretreatment, etching treatment, etc., and the plated surface becomes It will no longer be uniform. For this reason, uneven portions are formed on the type surface during printing, and the protruding periphery receives stress concentration, which speeds up the propagation of cracks, and even if plating is applied, a long printing life cannot be obtained. According to the inventor's experiments, under the conditions required for printing during normal use, the lifespan of the same character varies widely from 20,000 to 300,000 to 5,000,000 characters, which poses a practical problem. It was hot. This idea was made in order to eliminate the above-mentioned drawbacks, and in order to prevent variations in the strength of the printing surface, by simultaneously mixing the commonly used fibers and glass beads, the surface of the typeface could be improved. The purpose is to increase the stability and adhesion of the plating through mechanical bonding, eliminate cracking and peeling of the plating, and extend the life of the plating. This invention will be explained below based on the drawings. Figure 1 is a plan view showing an embodiment of this invention.
1 is a type body, 2 is a matrix type part, 3 is a finger part that supports the matrix type part 2, 4 is a ring part that supports the finger part 3, 5 is a spoke part that supports the ring part 4, 6 is a boss portion that supports the entire spoke portion 5, and 7 is a mounting hole for mounting a motor shaft (not shown) for character selection. The operation is well known and will therefore be omitted. In the typeface 1 constructed as described above, the constituent materials are polyacetal resin, carbon fibers or glass beads (diameter number + microns), and a mixture of these materials is mixed and molded as an example in this experiment. Shown in Table 1.

【table】

[Table] When these constituent materials are compared, the bending elastic modulus increases as the amount of carbon fiber increases. This means that since glass beads are spherical, they have no directionality and are subject to bending. In addition, the yield strength due to compression shows a higher value in all cases containing carbon fiber. In addition, when we conducted an actual printing life test, only glass beads had the longest lifespan of the matrix type part 2 among the three.
The longest one was 500,000 characters, followed by the one with carbon fiber and glass beads at 120,000 characters, and the shortest was 20,000 characters with just carbon fiber. This is thought to be because the amount of resin holding the carbon fibers generates cracks around the carbon fibers due to the force applied during printing operations, and the cracks propagate through the carbon fibers, promoting cracking and deformation. On the other hand, in the case of glass beads, because they are spherical, they can be easily etched uniformly, and because they have no directionality, when compressed, even if cracks occur, the resin cannot be completely peeled off from the surrounding surface of the glass beads. Furthermore, since the cracks in the surrounding resin layer do not become larger than the maximum diameter of the beads, and the glass beads do not come out, it is thought that this reduces the chance of shedding, loss, or abrasion of the typeface. FIG. 2 shows an example of a partial microscopic sketch of the ring portion 4 and finger portion 3 formed by mixing carbon fibers and glass beads with polyacetal resin. In this figure, 2c represents polyacetal resin, 2d represents carbon fiber, and 2e represents glass beads. It can be seen from this figure that the carbon fibers 2d are oriented in the longitudinal direction. In other words, it shows that the direction is good for bending in practical terms.
Note that the cross section is a vertical rectangle in the illustration, but
There is no practical problem even if the draft angle of the molding die is taken.
For these reasons, it is preferable to use a mixture of both types for the typeface 1 that is used for both bending and compression. By changing the molding method, it is possible to increase the proportion of glass beads 2e concentrated in the matrix type part 2, and the strength of the matrix type part 2 can be increased. FIG. 3 shows an example of a sketch obtained by microscopic observation of a partial cross section according to an embodiment in which plating is applied to the matrix type part 2 of the type body 1 which is formed by mixing both types as shown in FIG. 2. In this figure, 2a is an electroless copper plating layer that was etched to form a rough surface and then applied, 2b is a hard nickel layer, and the same reference numerals as in FIG. 2 indicate the same parts. Conventionally, when this type of plating was applied without glass beads and with 20% carbon fiber, the lifespan varied widely as described above. This is thought to be due to propagation of cracks due to carbon fibers, as in the case of no plating. Therefore, when the amount of carbon fibers 2d is reduced and the glass beads 2e are mixed in as in this invention, the etching solution surrounds the glass beads 2e,
Even when plated, the glass beads 2e are surrounded by a layer of polyacetal resin 2c, so the plating bond is a mechanical bond. In other words,
Provides an anchor effect and prevents peeling of plating. This can be inferred from the fact that when comparing the yield strength of plated products, the yield strength is 39 kg in the case of only carbon fiber 2d and 54 kg in the case of glass beads 2e. Furthermore, the amount of carbon fiber 2d is reduced,
Since the glass beads 2e are included, the surface is smoother than before, and even when etched, there is no protrusion of the carbon fibers 2d, indicating that internal stress is small. When plated, it exhibits a luster similar to ion-plating. In the printing life of the matrix type part 2 manufactured in this way, even with a platen hardness of H _S C91 and a printing energy of 9 mJ, it is abnormal even after 3.5 million prints, compared to 40,000 to 200,000 for conventional type. showed very good results. The fibers used in this invention are not limited to the carbon fibers 2d, but may be other fibers having the same effect, such as glass fibers. It goes without saying that the thickness of the fibers, the diameter of the glass beads 2e, etc. can be selected as appropriate. As explained above, this invention uses a material that is a mixture of glass beads and fibers and is integrally molded, so that the bending portions are made of fibers. Further, in the compressed portion, the anchor effect of the glass beads can be used to reduce the deformation of the printed character surface. Furthermore, in the case of plating, there is an advantage in that the anchor effect prevents the plating from peeling off. This effect can be applied not only to type but also as a plating material for abrasion resistance in terms of flatness, if the material strength of the material by mixing glass beads and fibers is allowed. It has practical effects.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a typeface showing an embodiment of this invention, FIG. 2 is a diagram showing an example of a sketch obtained by observing part of the ring part and finger part of FIG. 1 under a microscope,
FIG. 3 is a diagram showing an example of a sketch obtained by microscopic observation of a partial cross section of a plated matrix type portion according to an embodiment of the present invention. In the figure, 1 is a typeface, 2 is a matrix type part, 2a is an electroless copper plating layer, 2b is a hard nickel layer, 2c is a polyacetal resin layer, 2d is a carbon fiber, 2
e is a glass bead, 3 is a finger portion, 4 is a ring portion, 5 is a spoke portion, 6 is a boss, and 7 is a mounting hole.

Claims (1)

[Scope of utility model registration request] A plurality of spoke parts extending radially from the boss part, a ring part formed integrally with these spoke parts, and a matrix-shaped typeface formed at the tip of the ring part integrally protruding outward from the ring part. In a type body composed of a finger portion corresponding to a dial plate, at least the matrix type part of the type body is formed by mixing polyacetal resin with fibers and glass beads, and further, electroless copper plating is applied only to the type face. A typeface characterized by successive hard nickel plating.