JPH05278315A - Screen printing machine - Google Patents

Abstract

PURPOSE:To provide a screen printing machine not lowering the image density of printed matter and hard to generate strike-through contamination even under a low temp. environment condition in the winter season. CONSTITUTION:A screen printing machine is equipped with a cylindrical plate cylinder 3 around which stencil paper 4 is wound through a screen, the ink supply roller 15 provided so as to come into contact with the inner peripheral surface of the cylindrical plate cylinder 3, a heat applying means 2 applying heat to the inner surface of the ink supply roller 15 and the temp. detection sensor 13 coming into contact with the ink on the outer peripheral surface of the ink supply roller 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine.

[0002]

2. Description of the Related Art Conventionally, a stencil sheet is wound around a perforated cylindrical plate cylinder through a screen, and ink is exuded from the inside of the cylindrical plate cylinder, and a printing paper is passed between the stencil sheet and a printing roller. A stencil printing machine is known in which printing is continuously performed.

In this stencil printing machine, when the outside air temperature is as low as 10 ° C., such as in winter, the viscosity of the ink increases, and the ink does not easily exude from the screen, so that the outside air temperature is 20 ° C. The image density of the printed matter is reduced and set-off stains are likely to occur.

As measures against such a low temperature, for example,
Japanese Unexamined Patent Publication No. 63-272579 discloses a stencil printing machine in which a cylindrical plate cylinder is provided in a main body cover, and a warm air generator is provided in the main body cover close to the outer peripheral surface of the cylindrical plate cylinder. Has been done.

In Japanese Utility Model Laid-Open No. 1-131551, there is provided heat applying means for applying heat from the outside to the outer peripheral surface side of the cylindrical plate cylinder, and a temperature detecting sensor is provided near the outer peripheral surface of the cylindrical plate cylinder. There is disclosed a stencil printing apparatus which is provided in a section and detects the temperature in the vicinity of the section and controls the heat applying means depending on the level of the temperature.

[0006]

However, in both of these stencil printing apparatuses, a means for applying heat from the outer peripheral surface side of the cylindrical plate cylinder has been considered, but this heat is applied to the screen from the stencil sheet. Since it is transmitted to the ink sequentially through
There is a problem that it is very inefficient as a means for applying heat to the ink. In the latter stencil printing machine, the temperature detecting means also detects the temperature in the vicinity of the outer peripheral surface of the cylindrical plate cylinder, and if the temperature of the ink on the cylindrical plate cylinder is detected, its accuracy becomes poor. There is.

Above all, in both of these stencil printing machines, heat is applied from the outer peripheral surface side of the cylindrical plate cylinder, so that there is a problem that heat is not easily transferred to the ink in the cylindrical plate cylinder.

Therefore, in order to solve the above-mentioned problems, the present invention can be carried out even under low temperature environmental conditions such as winter.
An object of the present invention is to provide a stencil printing apparatus in which the image density of a printed matter does not decrease and settling stains hardly occur.

[0009]

The present invention has been made to achieve the above-mentioned object, and the invention according to claim 1 is a cylindrical plate cylinder around which a stencil sheet is wound through a screen, and An ink supply roller provided so as to be in contact with the inner peripheral surface of the cylindrical plate cylinder, heat applying means for applying heat to the inner surface of the ink supply roller, and a temperature detection sensor in contact with the ink on the outer peripheral surface of the ink supply roller, Is provided.

According to a second aspect of the invention, in the stencil printing machine according to the first aspect, the ink temperature of the outer peripheral surface of the ink supply roller is detected, and when the ink temperature is lower than a predetermined temperature, the heat applying means is operated. When the ink temperature is higher than a predetermined temperature, the heat application control means for deactivating the heat application means is provided.

According to a third aspect of the present invention, in the stencil printing apparatus according to the first or second aspect, the ink temperature on the outer peripheral surface of the ink supply roller is detected, and when the ink temperature drops to a preheating start temperature, the heat is applied. It is configured to have heat application control means for operating the application means.

[0012]

[Function] Since the heat applying means for applying heat to the inner surface of the ink supply roller and the temperature detecting sensor in contact with the ink on the outer peripheral surface of the ink supply roller are provided, heat is applied even if the ink viscosity is high at a low temperature. The ink is heated by the operation of the means, and the ink viscosity automatically becomes appropriate within a short time.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a stencil printing machine showing an embodiment of the present invention, and the overall configuration will be described together with its operation. In the figure, reference numeral 1 indicates a main body cover of the stencil printing apparatus, and a cylindrical plate cylinder 3 provided in the main body cover 1 is formed by forming a porous thin plate into a drum shape, and an outer peripheral surface of the cylindrical plate cylinder 3 is formed. Is wound with a screen (not shown), and the stencil sheet 4 is further wound on the screen.

The cylindrical plate cylinder 3 is rotationally driven in the direction of the arrow by a driving means (not shown), the paper feed roller 7 is rotated in synchronization with this rotation, and the printing paper 8 is transferred to the cylindrical plate cylinder 3 one by one. The pressure roller 9 ascends and abuts on the outer peripheral surface of the cylindrical plate cylinder 3 with this operation.

An ink supply roller 15 is provided so as to be in contact with the inner peripheral surface of the cylindrical plate cylinder 3, and an ink supply means 16 for supplying ink to the ink reservoir 5 is provided just above the ink supply roller 15. It is provided. The ink in the ink reservoir 5 on the ink supply roller 15 is transferred to the ink supply roller 15, and the transferred ink exudes sequentially on the cylindrical plate cylinder 3, the screen and the stencil base paper 4 respectively, and the surface of the stencil base paper 4 is extruded. Then, the image is printed on the printing paper 8 which is passed under the pressure of the printing pressure roller 9. On the other hand, the printing paper which has finished printing is peeled off from the cylindrical plate cylinder 3 by the paper ejection claw 12 and ejected to the paper ejection tray 10.

By the way, in the stencil printing apparatus of this type, as described above, for example, when the stencil printing apparatus main body is cold under a low temperature environment condition such as winter, the viscosity of the ink is high. Since the ink contained in the screen and the stencil sheet 4 is less likely to flow, if the printing is performed as it is, the image density of the printed matter is low and the settling stain easily occurs. If the viscosity of the ink is high, the penetration of the ink into the printing paper 8 will be delayed, and the ink will be poorly dried and settling stain will occur.

Therefore, in the present invention, there is provided heat applying means for applying heat to the inner surface of the ink supply roller 15 provided in contact with the inner peripheral surface of the cylindrical plate cylinder 3 of the stencil printing apparatus. In this embodiment, the halogen lamp 2 is used as the heat applying means. By supplying an electric current to the halogen lamp 2, the halogen lamp 2 is heated to heat the ink adhering from the inner surface to the outer surface of the ink supply roller 15 and to the outer surface of the ink supply roller 15. When this ink is heated, its viscosity decreases and its fluidity recovers, so that a printed matter with high image density and less set-off can be obtained.

Since the ink supply roller 15 and the inner peripheral surface of the cylindrical plate cylinder 3 are in contact with each other, when the cylindrical plate cylinder 3 is rotated, the heat of the outer surface of the ink supply roller 15 is transferred to the inner surface of the cylindrical plate cylinder 3. It is successively transmitted to the ink present on the peripheral surface, the screen, and the ink contained in the stencil sheet 4. The ink on the inner peripheral surface of the cylindrical plate cylinder 3 and the ink contained in the screen and the stencil sheet 4 immediately before printing have a good heat transfer because they are spread thinly, and the temperature rises in a short time. Therefore, the viscosity of the ink becomes low in a short time after the heat is applied by the halogen lamp 2 as the heat applying means, and a high-density image can be obtained.

Here, as the heat applying means, it is sufficient to use a halogen lamp 2 or the like, or to generate heat by passing a current through an electric resistor such as a print heater.

By the way, when the environmental temperature is relatively high, it is not always necessary to operate the heat applying means, and if it is operated all the time, the temperature of the ink supply roller 15 becomes too high, which is also against energy saving. Therefore, it is necessary to control the operation of the heat applying means according to the temperature change of the environment.

A temperature detection sensor 13 is provided so as to come into contact with the ink on the outer peripheral surface of the ink supply roller 15, and the temperature of the ink is detected by this. When the temperature detection sensor 13 detects that the temperature of the ink is lower than the predetermined temperature, the halogen lamp 2 as the heat applying means is operated to generate heat, and it is detected that the temperature of the ink is higher than the predetermined temperature. When this occurs, the halogen lamp 2 as the heat applying means is deactivated to stop the generation of heat. Here, the predetermined temperature means a temperature at which the ink has a desired viscosity, which is obtained by analyzing experimental data obtained by operating the stencil printing machine under various environmental temperature conditions. The temperature is preset and stored in the stencil printing machine by a known means.

In this way, the ink on the ink supply roller 15 inside the cylindrical plate cylinder 3 and the ink on the inner peripheral surface of the cylindrical plate cylinder 3 are controlled by controlling the operation of the heat applying means such as the halogen lamp 2. The ink contained in the screen and the stencil sheet 4 can be maintained at an appropriate temperature, and a printed image with high density and less set-off can be immediately obtained even when the environmental temperature is low.

In the embodiment of the present invention, the operation of the halogen lamp 2 as the heat applying means is controlled based on the temperature detection by the temperature detection sensor 13, and it is possible to perform a kind of preheating operation. For example, the ambient temperature tends to decrease at night when the stencil printing machine is stopped. Therefore, a temperature is set in advance so that the halogen lamp 2 cannot be immediately restored even if it is operated, and when such a temperature is detected by the temperature detection sensor 13 at night,
When the halogen lamp 2 is operated to set the ink viscosity so that a good image can be obtained and the ink is kept on standby, a printed matter having a good density can be obtained immediately at the start of printing. As described above, when the cylindrical plate cylinder 3 is rotated at the same time as the preheating operation described above, the ink in the ink reservoir 5, the ink on the ink supply roller 15, the ink on the inner peripheral surface of the cylindrical plate cylinder 3, the screen, Further, since heat is sequentially transferred to the ink contained in the stencil sheet 4, it is effective to immediately obtain a printed matter of good density.

In addition, if the preheating operation is not performed all night, the temperature detection sensor 13 operates at the same time when the power of the stencil printing apparatus main body is turned on, and if the current temperature is lower than an appropriate predetermined temperature, It is also possible to adopt a preheating system in which the halogen lamp 2 is automatically operated and the cylindrical plate cylinder 3 is rotated.

The rotational speed of the cylindrical plate cylinder 3 during preheating is
For example, a low rotation speed of about 10 rpm can be selected. If the temperature of the cylindrical plate cylinder 3 has risen to, for example, about 10 ° C. which is a predetermined temperature, the halogen lamp 2 is operated at the same time as printing is started, and the temperature is a proper temperature in a relatively short time.
Since the temperature rises to about 0 ° C., it is possible to obtain a printed matter with good image density relatively quickly. From this point of view, FIG. 2 shows an example of a control flow based on the conditions when the set temperature of the preheating operation is the predetermined temperature.

Here, the heat application control means is composed of a known automatic control device having the functions of steps 20 and 21 in FIG.

[0028]

As described above, according to the present invention, even if the ink viscosity is high at a low temperature, the ink viscosity can be made appropriate in a short time by the operation of the heat applying means, It is possible to obtain a printed matter with a high image density and a small amount of set-off stain. At the same time, it is possible to save the trouble of turning on and off the switch for activating and deactivating the heat applying means.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a stencil printing apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a control flow corresponding to the embodiment of FIG.

[Explanation of symbols]

 2 Halogen lamp as heat applying means 3 Cylindrical plate cylinder 4 Stencil sheet 13 Temperature detection sensor 15 Ink supply roller 16 Ink supply means

Claims (3)

[Claims] 1. A cylindrical plate cylinder around which a stencil sheet is wound through a screen, an ink supply roller provided in contact with the inner peripheral surface of the cylindrical plate cylinder, and heat is applied to the inner surface of the ink supply roller. And a temperature detection sensor in contact with the ink on the outer peripheral surface of the ink supply roller,
A stencil printing apparatus comprising: 2. The stencil printing apparatus according to claim 1, wherein the ink temperature on the outer peripheral surface of the ink supply roller is detected, and when the ink temperature is lower than a predetermined temperature, the heat applying means is operated to change the ink temperature. A stencil printing machine comprising heat application control means for deactivating the heat application means when the temperature is higher than a predetermined temperature. 3. The stencil printing apparatus according to claim 1 or 2, wherein the ink temperature on the outer peripheral surface of the ink supply roller is detected, and heat is applied to operate the heat applying means when the ink temperature drops to a preheating start temperature. A stencil printing machine having an application control means.