JPS5862053A - Offset printing machine - Google Patents

Abstract

PURPOSE:To obtain excellent printing quality, by tightly closing an inking room, controlling the internal temperature at a specified value, thereby maintaining the physical characteristics of the printing ink at a constant level. CONSTITUTION:The inking room 8 is composed of an inking arrangement, a dampening arrangement 7, and various rollers. The room 8 is tightly closed by a shielding cover 9 made of transparent synthetic resin (symbol 1 is a plate cylinder, 2 is a rubber blanket cylinder, 3 is an imperession cylinder, and 4 is a combining device), and controls the internal temperature at the specified value. Namely, the temperature in the inking room 8 obtained by performing the measurement by a sensor 13 is compared with a preset temperature by a comparator 4. When the difference is obtained, a cooling means 10 of a constant temperature device 16 is operated through a control device 15 by using the obtained difference signal. Air is circulated through the sequence of the constant temperature device 16, air supplying duct 11, the inking room 8, and air exhausting duct 12, thereby cooling the inking room 8 so as to obtain the preset temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an offset printing machine, in particular, it is possible to obtain good printing quality by controlling the temperature in the inking room to keep the physical characteristics of the printing ink constant. Regarding off-ring and cut printing machines.

In an offset printing press, a curved metal plate is attached to a cylinder to form the plate cylinder, a blanket cylinder is interposed between the plate cylinder and the impression cylinder, and the plate pattern is transferred to the surface of the blanket cylinder, and then In addition, there are many products that print on paper, including an inking device consisting of an ink droplet and various rollers, a dampening device for adding water to the inking device, and a printing device for the plate cylinder and rubber cylinder. and a paper feeding and paper ejecting device.

In such an offset printing press, frictional heat of the rollers, heat generation of the motor and pump, and even heat generation in the morning and evening are generated during operation, especially in the inking device, dampening device, and so-called ink bloom up to the surface of the plate cylinder. The temperature tends to change as a result of changes in temperature, and the print quality changes with this temperature change.

To elaborate, printing inks consist of a feed and a vehicle that keeps the pigments separate. The properties are very temperature dependent, so as the temperature of the inking room changes, the physical properties of the printing ink will also change, which, if left untreated, will result in uneven print quality. It happens.

In order to deal with the problem of variations in print quality caused by changes in the physical properties of printing ink, in view of the development of computer technology, in recent years, there has been an increase in the number of inks based on image information from the printing plate before printing begins. A preset system has been proposed that automatically adjusts the opening of !.

However, such a preset system is a technology that simply feeds back the printing results without considering the characteristics of the printing ink itself, so it is not a fundamental countermeasure, and the system itself is complicated. , and is expensive, and furthermore, it has the disadvantage that it cannot be easily attached to various types of offset printing presses.

The present invention was made in order to solve the above-mentioned problems, and aims to fundamentally prevent quality problems caused by changes in the physical properties of printing ink, inexpensively and easily. For this reason, the temperature in the inking room is kept constant.The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram showing an embodiment of an offset printing machine according to the present invention, in which a plate cylinder 1, a blanket cylinder 2, and an impression cylinder 3 of equal diameter are arranged at the center. Further, 4 is a paper feeding device, and 5 is a paper discharging device.

Above the plate cylinder 1, there is an inking device 6 for printing ink and a center (11).
A dampening device 7 that supplies water to the meat applicator 6 with the meat IIE fleas 41
Various rollers are provided between the plate cylinder 1, the inking device 6, and the dampening device 7, but the roles of these rollers will not be explained.

An inking room 8 is constituted by the inking device 6, the warming device 7, and various rollers, and the inking room 8 is hermetically sealed with a transparent synthetic resin shielding cover 9.

An air supply duct 11 and an exhaust duct 12 of the air cooling means 10 are opened in the space sealed by the isolation cover 9, and cold air is supplied so as to keep the temperature of the inking room 8 constant. A suitable temperature of 20-25°C is maintained.

Reference numeral 13 denotes a temperature sensor that measures the temperature inside the inking group 58. The value measured by the temperature sensor 13 is sent to a comparator 14 for calculation, and the control device 15 of the air cooling means 1o is controlled as necessary. Now that it's working,
A constant temperature device 16 is constituted by the air cooling means 1°, the temperature sensor 13, and the like.

Next, to explain the operation of the above-mentioned embodiment, as mentioned above, the physical characteristics of printing ink are very temperature-dependent, and therefore printing is affected by frictional heat from rollers, heat generation from various tools, and changes in temperature. There will be unevenness in quality. Therefore, the inking device 6, the dampening device 7, and the surface of the plate cylinder 1 are sealed with a transparent synthetic resin shielding cover 9, and the temperature inside the inking glue 58 is constantly measured by a temperature sensor 13. Ru. This measurement result is converted into 2 by the comparator 14.
The temperature is compared with a proper temperature of 0 to 25°C, and if the temperature is outside this range, a signal is sent to the control device 15 to operate the air cooling means 1o.

The air cooling means 10 continues to send cold air so that the temperature of the ink glue λ8 becomes an appropriate value, and this cold air flows through the air supply duct 1.
After being circulated from the inking room 1 to the inking room 8, it is sent out through the exhaust duct 12.

As a result, the inside of the ink glue 58 is kept at a constant temperature, so the printing ink is not exposed to temperature changes, and printing is always performed with constant physical properties such as viscosity, resulting in uneven printing quality. This eliminates the occurrence of scratches and allows you to obtain a high-quality finish.

In addition, the provision of such a constant temperature device fundamentally solves the problems caused by changes in the physical properties of printing ink.Furthermore, the structure is significantly simpler than that of conventional preset systems. It is simple and inexpensive, and can be easily applied to various types of offset printing machines.

In the above description, an air cooling means is used as the constant temperature device, but it is a matter of course that the thermostatic device is not limited to this and may be a water cooling means.

Further, as shown in FIG. 2, if a space 18 is provided inside the roller 17 where frictional heat is particularly likely to be generated, and cold air is introduced, the temperature can be maintained more effectively.

Furthermore, if circumstances permit, the entire offset printing press may be placed in a constant temperature room.

As described above, the offset printing press according to the present invention is provided with at least a cutoff cover that seals the inking room of the offset printing press, and a constant temperature device that keeps the temperature inside the cutoff cover constant. Particularly, there is an effect that problems in printing quality caused by changes in the physical properties of printing ink can be fundamentally prevented at low cost and easily.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing one embodiment of an offset printing machine according to the present invention, and FIG. 2 is a partial sectional view showing another embodiment. 1... Plate cylinder 2... Rubber cylinder 3... Impression cylinder 7... Dampening device 8... Inking room 9... Shutoff cover 10... Air cooling means 11... Air supply duct 12 ... Exhaust duct 13 ... Temperature sensor 14 ... Comparator 15 ... Control device 16 ... Constant temperature device 17 ... Roller 18 ... Space Fig. 1 Fig. 2

Claims (1)

[Scope of Claims] An offset printing machine characterized by being provided with an isolation cover that seals at least an inking room of the offset printing machine, and a constant temperature device that keeps the temperature inside the isolation cover constant. 2. The offset printing machine according to claim 1, wherein the constant temperature device is an air cooling means. 3. The offset printing machine according to claim 1, wherein the constant temperature device is a water cooling means. A space is provided inside the roller in the main inking room,
3. An offset printing press according to claim 2, characterized in that the press is adapted to introduce cold air.