Analysis of temperature control points of the hott

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Analysis on the key points of temperature control of offset press

· temperature of ink conveying device

most of the transmission power of a printer is used to drive the ink conveying device. On the ink conveying device, when the ink is separated, the mechanical energy becomes heat when the elastic rubber roller is rolled and the ink string roller moves back and forth. Therefore, people try to use circulating water to keep the inking roller and ink bucket roller constant temperature, and try to discharge this heat from the source. This circulating water is in the central water tank, and part of it is also adjusted to the required temperature in the lower unit attached to the printing unit. It is better to adopt full constant temperature (cooling and heating) so that the ink conveying device can reach the standard working temperature before starting printing

so far, there are three schemes for adjusting the temperature of the ink conveying device, which are compared in this paper. These three schemes are different due to the temperature measured at different places as a stable, efficient and energy-saving adjustment process:

1) the adjustment amount is the surface temperature of each ink conveying device

2) the regulating amount is the water temperature for the constant temperature of the ink roller injected into each ink conveying device

3) the regulating quantity is the water temperature in the central water tank of the thermostatic equipment

· the performance of oil cooling, especially high-end products, is not stable and reliable. However,

although the thermal power generated on the transmission mechanism and bearing on the transmission side of the offset press is relatively small, it is unlikely to be discharged, so it will cause the side parts to heat up. A high temperature of about 60~c can be felt where there are no transmission side components protected by the shield, which has an adverse impact on the temperature uniformity of the whole machine. The function of oil cooling is to ensure that the temperature of the side parts is not higher than the hand temperature

· fountain solution cooling

the so-called water film or alcohol wetting device usually uses cooled fountain solution to supply water, and its temperature is about 10 ℃. On the whole, the cooling of fountain solution has little effect on the heat dissipation of offset press. However, keeping the low temperature of the fountain solution is conducive to reducing the evaporation of alcohol in the mixing tank and the water conveyance device, and can improve the viscosity of the fountain solution

· the sample of the printing plate cylinder is generally short gauge distance (generally normal temperature sample). Temperature

waterless offset printing lacks the cooling effect of fountain solution. For the waterless offset press without constant temperature of ink conveying device, it is best to cool the plate cylinder by blowing air. The offset printing with water only needs the constant temperature of the inking device. The constant temperature of the printing plate cylinder is not included in the experiment introduced in this paper

· infrared (old) temperature sensor

all heating body surfaces will emit infrared rays, which can be measured by a sensitive radiation detector and used as a temperature display. For absolute measurement, it is necessary to calibrate or accurately understand the emission capacity of the relevant surface. In this paper, the infrared temperature sensor is used to measure the temperature on the inking device, surface measuring machine and blanket, so as to provide the adjustment amount for constant temperature (adjustment method 1)

· fluctuations in printing

for the increase of field density and gradient value, three adjustment methods can be used to judge with the help of printing sheets, which are extracted from more than 175000 sheets in mass printing. The printing plates are almost the same. It is mainly to determine the statistical standard deviation and the range of differences between the maximum and minimum values

Xu Shiyuan

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