JPH069942U - Heating device of automatic screen printing machine - Google Patents

Abstract

(57) [Abstract] [Purpose] By heating the printing table uniformly and evenly without changing the size or length of the automatic screen printing machine to form a heating table, the endless belt is heated by this conduction heat. Provided is a heating device capable of preventing bleeding of color paste and color mixture and enhancing the degree of color development to improve the quality of printed products. [Structure] In an automatic screen printing machine that prints by pasting a cloth to be printed onto an endless belt on a machine stand equipped with a large number of printing units consisting of a pair of screens and squeegees for intermittent printing. A table having an upper surface serving as a support surface for the endless belt, which is divided into units at intervals in the traveling direction of the table, a planar heating element unitized for each table and provided on the table, and each of the planar heating elements. A temperature sensor provided for each unit to detect the temperature of the table or the sheet heating element, and a detection signal from the temperature sensor provided for each unit of the sheet heating element controls the power supply to each sheet heating element. A heating device for an automatic screen printing machine consisting of a temperature control mechanism.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heating device for an automatic screen printing machine. More specifically, the printing table of the automatic screen printing machine is heated to form a heating table, and the conductive belt heats the endless belt to spread the color paste. It aims to improve the quality of printed products by preventing the occurrence of coloration and color mixture and increasing the degree of color development.

[0002]

[Prior art and its problems]

 The automatic screen printing machine is a so-called wet-on-wet printing method, which is an ideal printing method with high precision and high capacity and labor saving. That is, in a short cycle of about 2 seconds to 5 seconds, there is no time for drying the color paste, and multicolor printing is performed by overlaying the wet color paste with the wet color paste. Therefore, it has the following problems, which leads to a reduction in printing quality.

The exudation and color mixing of the a-colored paste are unavoidable, and it is difficult to obtain printing with a sharp contour. b The contour is crushed by the squeegee pressure of the subsequent printing unit. c The color paste permeates into the inside of the printing cloth, and the surface coloration is reduced. d In the case of thin fabrics, there is back-through of colored paste, which causes contamination inside the dryer that follows.

On the other hand, in hand-printing or traveling-type printing, since it is a wet-on-dry printing method, there is a long blank time between the printing of the first color and the printing of the second and subsequent colors. During this time, the color paste is almost naturally dried, so a vivid, deep printing can be obtained from the sharp contour and sufficient surface coloring.

Even in the conventional automatic screen printing machine, for the purpose of obtaining the printing quality in hand printing and traveling type printing, JP-B-36-18395, JP-B-38-3992 and JP-A-49-108389 are each used. As can be seen from the official gazettes, Japanese Utility Model Publication No. 35-22194 and Japanese Utility Model Publication No. 58-133436, many methods and devices have been proposed to dry the color paste applied by printing by heating. .

In the automatic screen printing machine, there is a strong demand for a wet-on-dry printing method, and many mechanisms have been considered as shown in the above proposal, but these have not been put into practical use. It gives a very strange feeling, but this is not practical due to the large size or lengthening of the device with the conventional mechanism, and the temperature of the entire printing surface is made uniform to dry the color paste. It is recognized that it was difficult to do it uniformly.

Therefore, an object of the present invention is to uniformly and evenly heat a printing table into a heating table without increasing the size or length of an automatic screen printing machine, and heat the endless belt with this conduction heat. In this way, it is possible to provide a heating device capable of preventing the exudation and color mixture of the color paste and increasing the degree of color development to improve the quality of the printed product.

[0008]

[Means for solving problems]

 According to the present invention, an automatic screen printing machine for performing printing operation by affixing a cloth to be printed to an endless belt and intermittently conveying it to a machine stand equipped with a number of printing units each consisting of a screen and a squeegee. In Table 2, the table is divided into units at intervals in the traveling direction of the endless belt, and the upper surface serves as a support surface for the endless belt; the planar heating element unitized for each table unit; A temperature sensor provided for each unit of the sheet heating element to detect the temperature of the table or the sheet heating element, and a detection signal from the temperature sensor provided for each unit of the sheet heating element to the sheet heating element. The heating device of the textile printing machine is composed of the temperature control mechanism that controls the power supplied to the machine.

The printing table of the present invention may be a so-called hard table or a soft table. In the former case, a rigid metal table is used, and a planar heating element is fixed to the lower surface thereof. In the latter case, a rigid metal substrate and a cushioning cover layer provided on the upper surface of the substrate are used, and the sheet heating element is provided between the substrate and the cover layer.

[0010]

[Action]

 In the present invention, the printing table is divided into units at intervals in the advancing direction of the endless belt, and the sheet heating element is provided for each table unit on the printing table. Since the sheet heating element has the advantage that it has the largest heating area and heat transfer area among various heating elements, if it is provided on the printing table in a united form for each printing unit, the actual printing will be performed. It is possible to directly and efficiently and uniformly and uniformly heat the table on which the operation is performed, and since no special area or volume for heating is required, the apparatus becomes large or long. This makes it possible to perform wet-on-dry printing operations with the same size as conventional wet-on-wet printing machines.

Further, according to the present invention, since each printing table and the sheet heating element are provided in the form of a unit divided in the longitudinal direction, the temperature is strictly controlled corresponding to each printing unit. There is an advantage that is possible. In the present invention, a temperature sensor and a temperature control mechanism are provided for each table unit for this purpose, and the temperature is input to the sheet heating element according to the temperature of the table or sheet heating element detected for each unit. Control the electrical input. As a result, the temperature on the endless belt can be kept within a predetermined range for each printing unit.

In an automatic screen printing machine equipped with a large number of printing units, the amount of color paste applied to each printing unit is different. Some printing units have a large amount of color paste, and some print units have a small amount of color paste. There are also units. According to the present invention, even when the amount of color paste applied to each printing unit is different, the temperature is detected for each table unit and the electric input to the planar heating element is controlled. Since the predetermined temperature control is performed, it is possible to make the degree of drying of the color paste on the fabric to be printed constant (dry), thereby improving the printing quality.

According to the present invention, the printing table is heated by the above-mentioned simple and inexpensive means to form a heating table, and the endless belt is heated by the conduction heat to cause the above-mentioned problems in the automatic screen printing machine. It is possible to improve the printing quality by eliminating

The present invention has a simple apparatus and does not require an extra space, and the printing table is unitized together with the heating element for each sheet. Therefore, the conventional wet-on-wet printing method can be easily converted to the wet-on-dry printing method by simply replacing the printing table of the conventional machine with the one of the present invention.

[0015]

【Example】

 FIG. 1 shows an outline side view of an automatic screen printing machine in which a heat table (hard table) of one embodiment of the present invention is arranged, and FIG. 2 shows an enlarged cross section of the heat table.

The endless belt 1 is stretched between drive rollers 2 and 3 at the front and rear of the printing machine, and is intermittently driven in the arrow direction by a known device. The printing cloth 4 is introduced into the printing machine from the front part (right side in the figure), adhered to the endless belt 1 by the sticking roller 5, conveyed intermittently, and printed by the plurality of printing units 6.

A printing table 7 is provided below the end rebel 1 over the entire printing area A. The printing table 7 is divided into units of a certain length, and a planar heating element 8 having a width and a length for heating substantially the entire surface of the printing table is provided on the lower surface (back surface) of the unit.

In this specific example, the printing table 7 is a so-called hard table and is made of a metal such as an aluminum plate, an iron plate, and stainless steel. The metal is thermally conductive, and the heat capacity of the metal acts to equalize the temperature of each part of each unit. It is desirable that the thickness is 3 or more. Further, in order to heat the printing table, it is preferable that the heating element, that is, the planar heating element, is brought into close contact with the lower surface (back surface) of the printing table, which allows convenient heating and wear of the planar heating element. Etc. can also be prevented.

The sheet heating element 8 is a single continuous sheet so that a temperature difference does not occur in the width direction of the endless belt 1. In the traveling direction of the endless belt 1, one having a narrow width for each unit is used. Plurals may be arranged in parallel. Further, the sheet heating elements 8 may be arranged only at the necessary places instead of the total number of the printing tables 7.

In this specific example, the sheet heating element 8 is protected by the heat insulating material 9 and the cover 10, and due to the elasticity of the heat insulating material 9, the entire heat generating surface is the lower surface (back surface) of the printing table 7. Close to. Alternatively, it may be adhered to the lower surface of the printing table 7 with an adhesive, a double-sided adhesive tape, or the like. Further, the printing table 7 is unitized together with the sheet heating element 8 and the cover 9 one by one.

As the sheet heating element 8, a heating carpet, a heating floor board, or a material that is mass-produced and marketed for various industries is used. These sheet heating elements include the following types, all of which are easily available in the present invention and can be conveniently used. a A woven fabric in which carbon fibers and the like are woven with heat-resistant fibers. b Carbon ink printed on a heat-resistant film in a grid pattern. c A thin metal resistance foil chemically etched in a grid pattern. Alternatively, metal resistance wires are arranged in the required length. Both sides and the periphery are sealed with an insulating / protective cover.

When the endless belt 1 is heated through the printing table 7 for the above purpose, the surface temperature of the endless belt 1 may decrease due to the drying or gelling of the color paste, or the fluidity of the color paste may decrease. Any adhesive may be used as long as it prevents mixing of the adhesives. This temperature varies depending on the type of color paste, but generally, 30 ° C to 70 ° C, especially 50 ° C before and after is optimal. When the room temperature is 20 ° C., it is sufficient if there is a temperature rise of about 30 ° C. and a heat retention heat quantity for maintaining this. In addition, if necessary, it is easy to provide a preheating device before reaching the printing area A.

The higher the surface temperature of the endless belt 1, the more effective it is in drying the color paste. However, when the surface temperature is 80 ° C. or higher, the elongation rate of the endless belt 1 becomes large and unstable due to the influence of heat. , The intermittent feed accuracy is impaired. In addition, there are problems such as drying of the screen mesh and clogging of the screen.

The above-mentioned commercially available sheet heating element has a heat generation temperature of 50 ° C. to 200 ° C., although it varies depending on the manufacturer and type. Therefore, the temperature required by the present invention can be easily obtained by selecting the type and specifications and adjusting the voltage applied thereto. The power density in this case is 700 W / m ^{2 to} 3000 W / m ² , and the working voltage is in the range of A · C 100 V to 200 V.

A temperature sensor 11 is attached to the sheet heating element 8 and is connected to a temperature control device 12. That is, the temperature sensor 11 detects the temperature of the table or the sheet heating element 8, and the temperature control device 12 controls the electrical input to the sheet heating element 8 by this detection signal, thereby performing a predetermined temperature control. . This operation is performed for each unit. If necessary, the voltage controller 13 controls the entire temperature. This operation is effective when the outside temperature is significantly different, such as in summer and winter.

FIG. 3 shows a schematic side view of an automatic screen printing machine having a heat table (soft table) according to another embodiment of the present invention, and FIG. 4 shows an enlarged cross section of the heat table.

3 and 4, the arrangement of the drive system of the endless belt and the printing unit is the same as that in the case of FIG. In this specific example, in order for the cage operation of the printing unit 6-2 to be smoothly performed with cushioning property while the screen 6-1 and the cloth 4 to be printed are in contact, Is provided with a cushioning cover layer 14, and tensioning members 15 for applying tension to the cover layer are provided at both ends of the table. The sheet heating element 8 is arranged between the table base 7 and the cushioning cover layer 14 for each printing unit, and the applied color paste is heated in the same manner.

FIG. 5 shows the relationship between the operation of the temperature control device in the hard table system of FIGS. 1 and 2 and the temperatures of the planar heating element and the endless belt. As an example of the case of FIG. 5, the case where the electric capacity of the planar heating element 8 is 2600 W / m ² and the voltage applied to this is AC 200 V is shown. The time T until the temperature reaches the same set temperature (70 ° C. in the embodiment) after the power of the temperature control device 12 is turned on is about 5 minutes.

When the set temperature is reached, the temperature control device 12 is turned off, but it is turned on again by decreasing the temperature t, and this is repeated. This temperature difference Δt is set to 2 ° C. The surface temperature of the endless belt 1 rises later than that of the sheet heating element 8, but in the embodiment, the saturation temperature becomes about 54 ° C. after about 15 minutes. The above time and temperature differ depending on the voltage applied to the sheet heating element 8 and the room temperature (normal temperature). In this embodiment, the temperature control is performed by the ON / OFF control of the power source, but it is also possible to perform the proportional control.

[0030]

[Effect of device]

 According to the present invention, the printing table and the planar heating element are provided in the printing machine in units divided in the longitudinal direction, and the temperature is detected for each unit and the electrical heating to the planar heating element is performed. By controlling the input and thereby providing the predetermined temperature control, the following advantages are achieved. The table itself on which the printing operation is actually performed can be heated directly and efficiently, uniformly and uniformly, and since no special area or volume is required for heating, the apparatus is enlarged or lengthened. This makes it possible to perform wet-on-dry printing operations with the same size as conventional wet-on-wet printing machines.

In the automatic screen printing machine equipped with a large number of printing units, even if the amount of color paste applied to each printing unit is different, the temperature is detected for each divided table unit and the planar heating element is detected. By controlling the electrical input to the fabric, and controlling the temperature in a predetermined manner, it is possible to make the degree of drying of the color paste on the fabric to be printed constant (dry), thereby improving the printing quality. Can be increased.

In the present invention, the device is simple and no extra space is required, and the printing table is unitized with the heating element for each sheet. Therefore, the conventional wet-on-wet printing method can be easily converted to the wet-on-dry printing method by simply replacing the printing table of the conventional machine with the one of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic side view of an automatic screen printing machine in which a heat table (hard table) according to an embodiment of the present invention is arranged.

FIG. 2 is an enlarged sectional view of a heat table of the textile printing machine of FIG.

FIG. 3 is a schematic side view of an automatic screen printing machine having a heat table (soft table) according to another embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a heat table of the textile printing machine of FIG.

FIG. 5 is a graph showing the relationship between the operation of the temperature control device in the hard table system of FIGS. 1 and 2 and the temperatures of the planar heating element and the endless belt.

[Explanation of symbols]

 1 Endless Belt 2 Front Driving Roller 3 Rear Driving Roller 4 Printing Fabric 5 Adhesive Roller 6 Printing Unit 6-1 Screen 6-2 Squeegee 7 Printing Table 8 Sheet Heating Element 9 Insulation Material 10 Cover 11 Temperature Sensor 12 Temperature Control Device 13 voltage regulator 14 cushioning cover layer 15 cover layer tension member.

Claims (3)

[Scope of utility model registration request] 1. An automatic screen printing machine for performing a printing operation by affixing an endless belt with a cloth to be printed on a machine stand having a large number of printing units each comprising a pair of a screen and a squeegee, and carrying the cloth intermittently, A table which is divided into units at intervals in the traveling direction of the endless belt and whose upper surface serves as a support surface for the endless belt, a planar heating element unitized for each table and provided on the table, and a planar heating element. The temperature sensor provided for each unit of the table or the surface heating element for detecting the temperature of the sheet heating element, and the detection signal from the temperature sensor provided for each unit of the sheet heating element supplies power to each sheet heating element. A heating device for an automatic screen printing machine, which comprises a temperature control mechanism for controlling. 2. The heating device according to claim 1, wherein the table is a rigid metal table, and a planar heating element is fixed to the lower surface of the table. 3. The table comprises a rigid metal base and a cushioning cover layer provided on an upper surface of the base, and the sheet heating element is provided between the base and the cover layer. The heating device described.