JPH01232620A - Precision printing method for key top - Google Patents

Abstract

PURPOSE:To save thermal energy by making the contact surface of a heating head with a sheet of paper from metal, providing a curvature engaging mutually with the curvature on the surface of key top to be printed, and thereby shortening the time for heating. CONSTITUTION:With movement of a piston 23 to the right, resin 24 accommodated in a hopper 20 is fed into a heating cylinder 18, kneaded by an extrusion screw 19, heated and sent to near a nozzle 17. Then the piston 23 is moved to the left, and the resin is extruded to the void between a movable die 14 and a stationary die 15, and a key top 1 is formed. Then the two dies 14, 15 are separated by hydraulic changeover by a die fastening cylinder 12, and the dies are opened. In this condition, the key top 1 is fitted on the stationary die 15, and this is removed from a fixed board 16 and mounted on a printing device. Then the side 4A of copying sheet 4 to be printed is put in contact with the oversurface of the key top 1, and heating is made by a heating head 6 while a pressure is applied by a pressure means directly from above it. The contact surface 6A of heating head with the copying sheet 4 is made of metal and consists of a curvature to mutually engage with the curvature on the surface of key top 1 to be printed.

Description

DETAILED DESCRIPTION OF THE INVENTION +3-11 Field of Industrial Application The present invention relates to a precision printing method for key tops used in typewriters and computer keyboards.

(3-21 Prior Art) In recent years, a large number of personal computers and other computers such as calculators, word processors, and laptop computers have been manufactured, all of which are equipped with keyboards; Since English typewriters and the like are also equipped with keyboards, there is a huge demand for them.

Each key on these keyboards has a key top, which is shown in Figure 5 ((a) is a plan view, (b) is a front view, (c) is a right side view, and (d) is a top view. The shape is as shown in the bottom view). As shown in the figure, the key top 1 is formed by printing required characters or symbols on the upper surface IA (and in some cases on the front surface IB) of a resin molded product having a substantially hollow trapezoidal shape. The molded product is PBT
(Polybutylene terephthalate
It is molded by injection molding or the like using a resin such as eneTelephthalatel, etc., and an appropriate rib IC is provided in the inner hollow part.

In order to print desired characters or symbols on the molded key top 1, a device as schematically shown in FIG. 6 (a partial view) has conventionally been used.

That is, in the same figure, this molded key top l
(usually the number required for all or the main parts of a typewriter or computer keyboard) are arranged by fitting the rib IC of the key top to the pedestal 3 provided on the jig 2, and A piece of paper (hereinafter simply referred to as "transfer paper") 4 on which reverse characters, reverse symbols, etc. are printed using dye on the top thereof, and its printed surface 4A is the top surface LA of the key top.
A sheet 5 made of an elastic material such as silicone rubber is placed on top of the sheet 5, and a sheet 5 made of an elastic material such as silicone rubber is placed on top of the sheet 5. If the dye printed on the transfer paper 4 is heated at a predetermined temperature for a predetermined time while being pressed by a heating head 6 connected to a heating wire (not shown, a heating wire or the like is usually conveniently used), the dye printed on the transfer paper 4 will sublimate. Penetrates the surface of the key top l. The top surface of the key top l normally forms a concave surface, but since the sheet 5 is an elastic body and deforms to follow the shape of the top surface of the key top I when pressed from above, the key top
The adhesion of the transfer paper 4 to the surface of the rib 1 is sufficient, and printing is performed accurately.

FIG. 7 is a diagram illustrating the transfer paper 4. As shown in FIG. In the same figure,
On the printing surface 4A of the transfer paper 4, characters or symbols to be printed on all or main key tops used in keyboards of typewriters, computers, etc. are reversed 4.
B is printed. Furthermore, since ink containing a dye that easily sublimates at a predetermined temperature is used for printing, the dye permeates into the key tops 1 easily and reliably.

However, the conventional key top printing method described above has the following drawbacks.

■ A sheet 5 of an elastic material such as silicone rubber is interposed between the heating head and the transfer paper, but since this sheet is usually a material with extremely poor heat conduction, the transfer paper is heated to a predetermined temperature. The time required for heating was long, and the heating efficiency was also poor.

■ In order to deform the sheet 5 made of an elastic material so that it follows the shape of the top surface of the key top, it is necessary to press it with a considerable force using the heating head 6. There was a fear that it might cause a problem.

■ The previous two drawbacks can be eliminated by omitting the elastic sheet and allowing the heating head to come into direct contact with the transfer paper. When the contact surface of the heating head with the transfer paper is a surface that does not engage with this concave curved surface (for example, when processing precision is poor). , the transfer paper is difficult to adhere to the top surface of the key top,
There was a drawback that printing was impossible or inaccurate.

■ As mentioned above, it is necessary to print not only the top surface of the key top but also the front surface thereof, but it has been difficult to print on the front surface using conventional methods.

(3-31 Problems to be Solved by the Invention The present invention solves the above-mentioned drawbacks of the conventional key top printing method, without interposing a sheet of elastic material between the heating head and the transfer paper. The heating time is fast, the heating efficiency is good, there is no deformation caused by applying excessive force to the key tops, etc., and it is possible to print accurately, and it is easy to print on the front of the key tops. The purpose of this paper is to provide a precise printing method for key tops.

+3-41 Means for Solving the Problems and Their Effects The present invention provides that in the conventional printing method, the center of the heating head is manufactured accurately, so that the center of the key top is aligned with the center of the heating head. If they match exactly, the shape of the contact surface of the heating head with the transfer paper should be the concave curved surface of the top surface of the key top (
This method was developed based on the fact that it is possible to form a curved surface that engages with the curved surface of the printed surface), and that it is also possible to make that surface a metal surface. A piece of paper with reverse characters, reverse symbols, etc. printed using ink containing dye is placed on the surface of the key tops, which are manufactured by molding and arranged on a board-shaped jig, and then a heat source is applied from above. The printing method for key tops used for keyboards such as typewriters and combination machines is as follows: heating to a predetermined temperature while pressing with a connected heating head, and sublimating and penetrating the dye into the surface of the key tops. The above-mentioned problems have been solved by improving the system. That is, the precision of the key top is characterized in that the contact surface of the paper piece of the heating head is made of metal and has a curved surface that mutually engages with the curved surface of the printing surface of the key top. This is a printing method.

To use this method, as mentioned above, accurate centering of the key tops is required, which requires a board-shaped jig,
It is most convenient to use a mold that is removably attached to an injection molding device and a molded product that is attached to the mold as the key tops arranged on it, but there are other methods. For example, if you use a jig that is centered very precisely, you will be able to line up the key tops unevenly.
Of course, other methods may be used to ensure accuracy.

(3-51 Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram illustrating an injection molding apparatus used in manufacturing a key top according to the present invention. In the figure, an injection molding device 11 has a mold clamping cylinder 12. A movable plate 13 fixed to the piston of the cylinder and reciprocating; a movable metal 14 fixed to the movable plate and reciprocating; a fixed plate 16 fixed to a frame or the like; removably fixed to the fixed plate. A fixed mold 15 and a heating cylinder 18 equipped with a heating device.
, an extrusion screw 19 housed inside the heating cylinder, a nozzle 17 provided at one end of the heating cylinder 1B and connected to the resin passage of the fixed mold 15, and a nozzle 17 attached near the other end of the heating cylinder. a hopper 20, an injection cylinder 22 connected to the other end of the heating cylinder;
Piston 23 housed inside the injection cylinder. It consists of a hydraulic motor 21 etc. for driving the extrusion screw.

The resin 24 stored in the hopper 20 is transferred to the piston 23
is fed into the heating cylinder 18 while moving to the right in the drawing, mixed by the extrusion screw 19, heated at the same time, and sent to the vicinity of the nozzle 17. Then, the piston 23 is hydraulically fed to the left in the drawing. The resin is molded into a movable mold 14 and a fixed mold 15.
The key top 1 is extruded into the gap formed by the key top 1. FIG. 1 shows exactly this state.Sixth, the hydraulic pressure of the mold clamping cylinder 12 is switched, the movable mold and the fixed mold are separated, and the molds are opened.

In this state, the key top l of the molded product is attached to the fixed mold 15, and it is removed from the fixed plate and immediately shown in Figure 2 (a diagram including some parts). In the case of zero keys attached to the printing device as shown, the key top l is the fifth key.
Although it is exactly the same as that illustrated in the figure, the printing device is different from that described in FIG. That is, the printed surface 4A of the transfer paper 4 is brought into contact with the upper surface of the key top 1 mounted on the fixed mold 15, and an appropriate suppressing means is directly applied from above without using the elastic material sheet 5. Then, it is heated to a predetermined temperature while being pressed by a heating head 6 connected to an appropriate heating source. The contact surface 6A of the transfer paper 4 of the heating head is made of metal, and the contact surface has a curved surface that engages with the curved surface of the printing surface of the key top.

FIG. 3 ((a) is a front view, (b) is a right side view, and (c) is a bottom view) is an enlarged view of the contact portion of the heating head 6 against the transfer paper 4, and is shown to a reduced scale. is almost the same as that in Figure 5.

As shown in the figure, the contact surface 6A of this example heating head is a curved surface (concave curved surface) of the upper surface of the key top.

It has a curved surface (convex curved surface) that engages with the other two (convex curved surface).

Figure 4 ((A) is a front view, (B) is a right side view, and (C) is a bottom view) shows the contact portion of the heating head of another embodiment of the present invention. Thus, this heating head is provided not only with an abutment surface 6A against the upper surface of the key top, but also with an abutment surface 6B having a curved surface that mutually engages with the surface of the front surface IB of the key top. As mentioned above, in some cases it is necessary to print not only on the top surface of the key top, but also on the front surface, but if a heating head like the one shown in this example is used, the transfer paper 4 can be printed on the top surface of the key top It can print not only on the IA but also on the front IH.

In the embodiments described above, the key top used in the printing device is mainly a molded product attached to a mold that is removed from an injection molding device, but as mentioned above, this is also applicable to other types of key tops. For example, key tops may be arranged manually on a precisely centered jig (though, of course, the present invention can also be effectively implemented in that case.

(3-61 Effects of the Invention When printing on key tops, the present invention uses a metal surface for the transfer paper contacting surface of the heating head, and also provides a curved surface that engages with the curved surface of the printing surface of the key top. etc., it shows the following excellent effects.

■ Since an elastic sheet with poor heat conductivity is not used, the time required for heating is shortened, and the heating efficiency is good, so thermal energy can be saved.

■ If the molded product attached to the mold removed from the injection molding equipment is used as the key top for the printing device immediately after molding, additional heating will be minimal, resulting in even greater savings in thermal energy. As a result, the heating time is further significantly shortened.

■ Since no elastic sheet is used, there is no need for a large pressing force that would deform one elastic body.

Therefore, no excessive force is applied to the key top, and there is no risk of deformation.

■ It is possible to choose from a wide range of types of transfer paper.

■ You can easily print on the front surface of the keyboard (not just the top surface).

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating an injection molding device used in manufacturing a key top according to the present invention, FIG. 2 is a diagram including a partial cross section illustrating a printing device used in the present invention, and FIG.
(A) is a front view, (B) is a right side view, (C) is a bottom view)
4 is an enlarged view of the contact portion of the heating head 6 against the transfer paper 4, and FIG. 4 ((a) is a front view, (b) is a right side view, and (c) is a bottom view) A diagram showing the contact part of the heating head of another embodiment, FIG. 5 ((A) is a plan view, (B)
6 is a front view, (C) is a right side view, (D) is a bottom view) is a diagram illustrating a key top, FIG. 6 is a diagram including a partial cross section illustrating a conventionally used printing device, FIG. 7 is a diagram showing the transfer paper. ■...Key top IA...Top surface 1B...Front IC...Rib 2...Jig 3...Pedestal 4...Transfer paper 4A...Printed surface 4B...Character, symbol 5... Seat 6... Pressing mechanism 6A... Contact surface 6B... Contact surface 11... Injection molding device 12... Mold clamping cylinder 13... Movable platen 14... Movable mold 15...
Fixed mold 16... Fixed plate 17... Nozzle
18...Heating cylinder 19...Extrusion screw 20...Hopper 21...Hydraulic motor 22...
・Injection cylinder 23...Piston 24...Resin patent applicant
Tossuri Co., Ltd. Agent Patent Attorney Tsukamoto Daisan Department Figure 2 (εF ￥, Ri(c)

Claims (2)

[Claims] (1) A piece of paper with reverse letters, reverse symbols, etc. printed using ink containing dye is placed on the surface of the key tops, which are manufactured by molding resin and arranged on a board-shaped jig. In a method for printing key tops used for keyboards of typewriters, computers, etc., the key tops are heated to a predetermined temperature while being pressed by a heating head connected to a heat source, and the dye sublimates and penetrates into the surface of the key tops. A precision printing method for key tops, characterized in that the contact surface of the paper piece of the heating head is made of metal and has a curved surface that mutually engages with a curved surface of the printing surface of the key top. (2) The board-shaped jig and the key tops arranged on it are a mold that is removably attached to an injection molding device, and a molded product that is attached to the mold. The precision printing method for key tops according to claim 1.