The impact of temperature on the quality of the print in the printing process


Published on:

2019-01-03

Abstract: Introduction to printing machinery knowledge - characteristics - classification chapter: the article mainly introduces the temperature of the ink delivery device, oil cooling, fountain solution cooling, plate cylinder thermostat, infrared (old) temperature sensor, the characteristics of fluctuations in printing and other knowledge. Printing process temperature on the impact of print quality ink delivery device temperature of a printing press drive power is mostly used to drive the ink delivery device. In the ink delivery device, when the ink separation, flexible rubber roller grinding and string ink roller back and forth when the mechanical energy is turned into heat. Therefore, people try to use circulating water to make the ink string roller and the ink hopper roller constant temperature, and try to discharge this heat from the point of origin. This circulating water in the central water

The impact of temperature on the quality of the print in the printing process

Abstract: Introduction to printing machinery knowledge - characteristics - classification chapter: the article mainly introduces the temperature of the ink delivery device, oil cooling, fountain solution cooling, plate cylinder thermostat, infrared (old) temperature sensor, the characteristics of fluctuations in printing and other knowledge.

 

The impact of temperature on the quality of the print in the printing process

Ink delivery device temperature

The majority of a press's drive power is used to drive the ink delivery unit. In the ink transfer unit, when the ink is separated, the mechanical energy is turned into heat when the flexible rubber rollers are crushed and the ink hopper rollers are cascaded back and forth. Therefore, people try to use circulating water to make the string ink roller and the ink hopper roller constant temperature, and try to discharge this heat from the point of origin. This circulating water is adjusted to the desired temperature in the central tank and partly in the lower unit attached to the printing unit. It is preferable to use full thermostat (cooling and heating) so that the ink delivery unit can reach the standard operating temperature before printing begins.

Three options for regulating the temperature of the ink delivery unit can be implemented so far, which are compared in this paper. These three options differ due to the measurement of the temperature as a regulating quantity at different locations:

1) The adjustment amount is the surface temperature of each ink delivery unit.

2) The adjustment amount is the temperature of the water injected into each ink delivery device for the constant temperature of the ink rollers.

3) The adjustment amount is the water temperature in the central tank of the thermostat.

·Oil cooling

Although the heat power generated on the drive mechanism and bearings on the drive side of the offset printing machine is relatively small, it causes the side parts to heat up because the possibility of discharge is not high. The high temperature of about 60~C can be felt in the place of the drive side parts without shield protection, which has a negative effect on the temperature uniformity of the whole machine face width. The function of oil cooling is to make the temperature of the side parts not higher than the hand temperature.

·Fountain solution cooling

The so-called water film or alcohol wetting device is usually supplied with a cooled fountain solution, whose temperature is about 10°C. From an overall perspective, fountain solution cooling has little effect on the heat dissipation of the offset printing machine. But keeping the fountain solution cool is good for reducing the evaporation of alcohol in the mixing tank and in the water delivery device, and can improve the viscosity of the fountain solution.

·Plate cylinder thermostat

Waterless offset printing lacks the cooling effect of the fountain solution. For waterless offset presses that do not have a constant temperature for the ink delivery unit, it is best to cool the plate cylinder by blowing air on it. Offset printing with water requires only a constant temperature for the ink delivery unit. The plate cylinder thermostat is not included in the experiments presented in this paper.

·Infrared (old) temperature sensor

All heat emitting surfaces emit infrared rays, which can be measured with a sensitive amplitude detector and displayed as temperature. For absolute measurements a calibration or accurate knowledge of the emissivity of the surface in question is required. The infrared temperature sensor is used in this paper to measure the temperature on the ink delivery device, the surface measuring machine parts and the blanket in order to provide the amount of regulation for constant temperature (regulation method 1).

·Fluctuations in printing

For the field density and order value increase can be judged by three adjustment methods with the help of sheets, which are drawn from more than 175,000 sheets in a large print run. The printing plates are almost identical. The main thing is to determine the standard deviation of the statistics and the range of differences between the maximum and minimum values.