JP2001026094A - Automatic pad printing machine and key tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive automatic printing machine, in which even if oil-based ink is used, uselessness of ink and volatilization of an organic solvent can be held down and printing is effectuated on the surface of a key top without reducing printing precision and to provide a key tape which is formed by efficiently performing its printing. SOLUTION: A character and a symbol or the like is printed on the key tape formed between tapes, in which a plurality of key tops 20 are formed by injection molding, by using the pad printing machine, in which oil-based ink applied to a printing pattern is supplied by an ink-jet printer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pad printing machine having an ink replenishing device using an ink jet printer, and a plurality of key tops used in a portable telephone, a personal computer or the like printed by the pad printing machine. The present invention relates to a belt-shaped intermediate product (key tape) formed between tapes formed by molding.

[0002]

2. Description of the Related Art As shown in FIG. 1, a general printing method of characters and symbols on a key top is performed by engraving a printing pattern by etching or the like on a printing plate 11 having a marking recess 13 formed thereon. Is applied, the excess oil-based ink 12 other than the engraved concave portion 13 is scraped off, the residual oil-based ink in the engraved concave portion 13 is transferred to the transfer pad 14, and a predetermined position on the surface of the key top 20 aligned with the printing jig is formed. It is printed by the pad printing to copy. The key top 20 of the mobile phone is in the form of a lens having a flat rear surface and an uneven outer surface, and is printed on the flat surface of the rear surface with the oil-based ink 12 by silk printing.

[0003]

In conventional pad printing or silk printing, ink waste is inevitably generated, and oily ink is diluted with a volatile organic solvent such as thinner. Solvents are released into the atmosphere. Furthermore, since the viscosity of the oil-based ink increases every moment due to the volatilization of the solvent, it is necessary for the operator to adjust the viscosity of the oil-based ink in a timely manner. Such viscosity adjustment of the oil-based ink depends on the experience of a skilled worker, making it difficult to automate the viscosity management of the oil-based ink, and the printing process has to rely on human naval tactics. Key tops such as personal computers have been standardized, such as by unifying cylindrical shapes, and model changes have almost disappeared, so they are produced in Southeast Asia, where labor costs are low, and printing waste and organic solvents are used. Pollute developing countries such as Southeast Asia.

[0004] Since a key top for a cellular phone has a lens-like thick shape, it is necessary to raise a mold temperature to around a thermal deformation temperature of the resin so as to prevent a cooling spot due to shrinkage of the resin. It is very difficult to exhaust gas, and very delicate management of molding conditions is required, such as making the filling speed less than half the capacity of the molding machine. Therefore, the molding yield is poor, the molding cycle is long, it is difficult to increase the number of moldings, and it is difficult to reduce the molding cost.

[0005] In addition, key tops for mobile phones are constantly required to be novel and fresh due to intensified sales competition, and their design shapes, display parts, colors, and the like are rapidly changing, and the manufacturing process is greatly changed each time. Inevitably, domestic production is being used. In the manufacturing process, every time the model is changed, it is necessary to update the jig and the alignment device in each process from the display process to the assembly process, and there is naturally a limit to the rationalization equipment investment. Therefore, there is a need for an efficient and versatile key top alignment method that can respond to these changes in market needs.

In an ink-jet printer, water-based inks can generally print finely by increasing the dot density. However, they do not have quick drying properties and make printing on plastic materials difficult even in terms of weather resistance. Conversely, oil-based inks
Although it is suitable for printing on plastic materials in terms of quick drying and weather resistance, it is difficult to increase dot density,
In order to increase the dot density, a very expensive printing machine is required. Accordingly, an object of the present invention is to provide an inexpensive automatic printing machine that can suppress ink waste and volatilization of an organic solvent even when an oil-based ink is used, and that can print on a key top surface without lowering printing accuracy, and the efficiency of printing. An object of the present invention is to provide a key tape which is formed by performing the method.

[0007]

As a result of studying to solve the above problems, attention has been paid to the evolution of ink jet printers accompanying the recent spread of personal computers and digital cameras.
The use of ink-jet printers solves the problems of oil-based ink viscosity management, residual ink processing, and maintenance of oil-based inks, which are the biggest bottlenecks of automation in pad printing machines, and uses a transfer method even when the dot density is low. As a result, they have found that high-precision printing can be performed on the surface of the key top, and have reached the first invention. That is, in a pad printing machine for copying the oil-based ink applied to a printing pattern imprinted on a printing plate with a transfer pad and transferring it to a printing substrate to perform printing, the oil-based ink applied to the printing pattern is an inkjet printer. The pad printing machine is characterized by being supplied by a pad printing machine.

By using a key tape in which a plurality of key tops are formed between tapes formed by injection molding, transfer printing using the pad printing machine of the first invention can be performed efficiently. Knowing that we can do it, we have reached the second invention. That is, a plurality of key tops that need to be printed at required locations on a surface used for a personal computer or the like are key tapes formed between tapes formed by injection molding, and are provided at required locations on the surface. A key tape, wherein printing is performed by using the pad printing machine according to claim 1.

[0009] Even a lens-shaped thick key top is formed by performing two injection moldings by moving in the same mold.
The thickness can be shared for each molding, significantly reducing moldability issues such as cooling spots due to resin shrinkage, keeping the mold temperature low, and obtaining a key tape with a stable shape without deformation. Knowing that it is possible to achieve the third invention. That is, a plurality of lens-shaped key tops made of a light-transmitting resin used for mobile phones and having a flat back surface and an uneven outer surface are formed by two injection moldings by moving in the same mold. Wherein each of the key tops is formed between tapes formed by a first injection molding, wherein the key tops are formed by a first injection molding formed by a first injection molding. With the molding part, the second injection molding part formed by performing the second injection molding on the first injection molding part is integrated,
A key tape characterized in that printing on the back surface is performed using the pad printing machine according to claim 1.

[0010]

FIG. 2 shows an embodiment of a pad printing machine using an ink jet printer according to the first invention, with reference to printing process diagrams (a), (b) and (c). In the printing process diagram (a), the printing plate 11 is formed by engraving a printing pattern on a mirror-finished metal plate surface by etching or the like.
An engraved recess 13 is formed. The ink head of an ink jet printer (not shown) performs a linear reciprocating scan at an appropriate distance on a printing plate 11 connected to a feed mechanism of the ink jet printer. The enlarged detailed view (d) of the printing process diagram (a) represents the ink droplet 12a of the oil-based ink dropped from the ink head. Oil-based ink drop 12a
When the transfer pad 14 is pressed down on the printing plate 11,
Control is performed to such an extent that it does not protrude out of the engraved concave portion 13. The printing step diagram (b) shows that the transfer pad 14 is
3 shows a state in which the oil-based ink 12 in 3 is going to be adsorbed. The printing process diagram (c) shows a state where the transfer pattern is transferred from the transfer pad 14 to the key top 20.

Here, the printing process diagrams (a), (b),
(C) illustrates a printing process for one key top for clarity of the illustration. However, in practice, a plurality of sets of key sets can be simultaneously transferred and printed within the printing area of the inkjet printer. Can be. Further, if an ink head is additionally provided for multicolor printing, transfer printing of a plurality of colors can be performed simultaneously. However, if the colors overlap, it is necessary to connect printing presses. Therefore, the pad printing machine of the present invention is standardized and made mobile. The ink jet printer is provided with a head cleaning mechanism, and the ink supply mechanism is a stationary type, and is designed to be an ink cartridge for viscosity management. Regarding the dot density of inkjet printer,
That the printing accuracy depends on the photo-etching accuracy of the print pattern of the engraved recess 13 and the transfer accuracy of the transfer pad 14;
Set to several tens of dpi to reduce the cost of inkjet printers.

FIG. 3 is a front view showing an embodiment of the key tape according to the second invention. First, using a saturated polyester resin such as a PBT resin for the background color, the connection end 21 is formed on one side.
Perform an initial molding of the keyset with Next, the mold is moved to a space adjacent to the other side in the mold, and the next molding is performed while melting and integrating the connection end 21. By repeating a series of operations, a belt-shaped key tape is formed. Resin is supplied to the key top 20 from the pin point gate 22. The tapes 23 on both sides are provided with holes 24 at a constant pitch that mesh with the teeth of a transfer device such as a sprocket in a printing process. The key tape is sent to the pad printing machine of the first invention, and characters and symbols are efficiently printed thereon.

Here, the key sets need to have the same background color. The connecting branches 25 are provided to the extent necessary to maintain and stabilize the positions between the tapes 23 and the plurality of key tops 20.

FIG. 4 is a front view showing an embodiment of the key tape according to the third invention. First, using a translucent polycarbonate resin or the like, the first injection molded part 2 of the key top is used.
An initial molding to form Oa is performed. Next, it is moved to a space adjacent to the other side in the mold, and the second injection molding is performed on the first injection molded portion 20a while melting and integrating the surface layer of the first injection molded portion 20a of the key top. The following molding is performed to form the second injection molded portion 20b formed by performing the above. The keytop 20 is formed by repeating a series of operations. In the first injection molding part 20a of the key top 20,
Resin is supplied from the first pin point gate 22a. The resin is supplied to the second injection molding part 20b of the key top 20 from the second pin point gate 22b. In the case of molding with the same resin, such double molding can be performed by shifting the phase of one injection in the same mold in a mold having a moving mechanism. Sunahachi, first injection molding part 2
0a and the second injection molded part 20b are formed by the same injection. FIG. 5 is a sectional view showing an embodiment of the key top 20 according to the third invention. The thickness of the first injection molded part 20a is
The second injection molded portion 20b is formed so that the thickness thereof is substantially uniform. The other description is omitted because it is the same as the description of the second invention.

Here, the first injection molded portion 20a may have sinks (dents) due to the contraction of the resin. This is because the key top 20 is repaired by the second injection molded portion 20b and does not appear in appearance. Also, the boundary layer between the first injection molded part 20a and the second injection molded part 20b is 1
Since the batch injection is only out of phase, the inside of the first injection molding section 20a maintains a high temperature, and the two are easily melted. Therefore, the problem of moldability such as cooling spots due to resin shrinkage is significantly reduced, the mold temperature can be kept low, a key tape with a stable shape without deformation can be obtained, and the molding cycle can be shortened. Can be planned.

[0016]

As described above, according to the present invention, even if oil-based ink is used, ink waste and volatilization of organic solvent can be suppressed, and there is no need to constantly wait for skilled workers for adjusting the viscosity of oil-based ink. In addition, an environmentally friendly automatic printing production line having sufficient printing accuracy can be constructed. Further, by connecting the injection molding process and the printing process, it is possible to construct a key top manufacturing line capable of semi-permanent continuous automatic operation. Furthermore, Japanese Patent Application No. 10-252
The production line including the printing of 930 key tops can be shared, and a general-purpose automatic molding and printing production line can be constructed. FIG. 6 shows the concept.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a conventional pad printing process.

FIG. 2 is a perspective view showing a pad printing process according to the present invention.

FIG. 3 is a front view of the key tape according to the present invention.

FIG. 4 is a front view showing another example of the key tape according to the present invention.

FIG. 5 is a sectional view of a key top in another example of the key tape according to the present invention.

FIG. 6 is a perspective view showing a concept according to the effect of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 printing plate 12 oil-based ink 12a ink drop of oil-based ink 13 stamped recess 14 transfer pad 20 key top 20a first injection molded part 20b second injection molded part 21 connection end 22 pin point gate 22a first pin point gate 22b second pin point Gate 23 tape 24 hole 25 connecting branch

[Procedure amendment]

[Submission date] March 1, 2000 (200.3.1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

[0016]

As described above, according to the present invention, even if oil-based ink is used, ink waste and volatilization of organic solvent can be suppressed, and there is no need to constantly wait for skilled workers for adjusting the viscosity of oil-based ink. In addition, an environmentally friendly automatic printing production line having sufficient printing accuracy can be constructed. Further, by connecting the injection molding process and the printing process, it is possible to construct a key top manufacturing line capable of semi-permanent continuous automatic operation. Further, the production line can be shared, and a general-purpose automatic production line for injection molding and printing can be constructed. Fig. 6
Shown in

Claims (3)

[Claims] 1. A pad printing machine for copying an oil-based ink applied to a printing pattern imprinted on a printing plate with a transfer pad, transferring the oil-based ink to a printing substrate, and performing printing, wherein the oil-based ink applied to the printing pattern is And a pad printing machine supplied by an ink jet printer. 2. A key tape formed between injection-molded tapes, wherein a plurality of key tops which need to be printed at predetermined locations on a surface used for a personal computer or the like are provided. A key tape, wherein printing is performed at a required location using the pad printing machine according to claim 1. 3. A plurality of lens-shaped key tops made of a light-transmitting resin used for a cellular phone or the like and having a flat back surface and an uneven outer surface are moved in the same mold and ejected twice. A key tape formed by molding and wherein each of said key tops is formed between tapes formed by a first injection molding, wherein the key tops are formed by a first injection molding. Along with the first injection molded portion, the second injection molded portion formed by performing a second injection molding on the first injection molded portion is integrated,
A key tape, wherein printing on the back surface is performed using the pad printing machine according to claim 1.