LED-UV Printing Curing System Design Based On Offset Printing

LED-UV(ultraviolet)printing curing is a new type of green printing curing technology that uses LED light source to cure UV ink.It has become a research hotspot in the field of printing and curing.Compared with the traditional UV mercury light source curing method,it has the advantages of energy saving,environmental protection,long service life,high working efficiency and small heat radiation.However,there are still problems such as low effective radiation capability,poor heat dissipation,and low controllability.In response to the above problems,this paper carried out the design of LED-UV printing curing system based on offset printing.The main contents are as follows:In order to improve the reliability of the curing system,the structure design of the light source system and the series-parallel design are carried out.The curing width of the light source system is 520mm,which consists of 24 substrates.The LEDs on the substrate are grouped in parallel,and each group is connected in series.Any LED damage,the system can still work stably for a long time.If any substrates are damaged,only small substrates need to be replaced to reduce the replacement cost.In order to make the light source system work steadily,a flyback constant-current drive power supply with high efficiency and on-line adjustment is designed by using single-stage active APFC(active power factor correction)converter.When the curing system is working for a long time,the ultraviolet irradiance is kept above 6000mW/cm~2.In order to improve the heat dissipation effect of curing system,the thermal resistance analysis of heat transfer path and the channel structure design of heat sink plate were carried out.The factors influencing the thermal resistance of each part of heat transfer path from the PN junction of LED to the surface of heat sink plate were analyzed.Three dimensional model and finite element model of heat sink plate with different channel structures are established.The temperature distribution on the plate surface of the same inlet section at different flow velocities is simulated,and the relationship among flow velocity,flow rate and flow resistance is analyzed,as well as the influence on pump power consumption.When the inlet water cooling liquid is 30℃,the maximum temperature of PN junction is not more than 42℃.In order to improve the controllability of the curing system,a control system that can collect the voltage,current,printing speed,substrate width and temperature of the curing system is designed,and the curing width can be automatically adjusted according to the change of the substrate width,and the output power can be automatically adjusted according to the speed change.The control system is based on STM32 single-chip microcomputer with anti-industrial interference capability,and the touch screen is used as the upper computer.The control system monitors and controls the working status of the printing and curing system in real time.