Patent ID: 8166875

Claim:
A screen printing apparatus for collectively printing a soldering paste on electrodes for connecting electronic components, which are formed on individual substrates, with respect to a plurality of individual substrates held on a carrier, comprising: a mask plate provided with pattern holes corresponding to the electrodes; a positioning device for two-dimensionally positioning the carrier with respect to the mask plate based on positioning parameters; a squeegee for printing a soldering paste on the electrodes via the pattern holes by executing a squeegeeing motion in sliding contact with the mask plate; a print inspection portion for detecting a position of the soldering paste printed on each individual substrate and detecting position deviation quantity of the soldering paste with respect to the electrodes as soldering position deviation data indicating positional deviation quantity for the electrodes; a feedback data supply portion for supplying feedback data to improve the positional deviation state based on statistical data of positional deviation quantity for individual substrates, in which the positional deviation quantities are statistically processed for each individual substrate; and a data updating portion for updating the positioning parameters based on the feedback data, wherein the feedback data supply portion obtains a plurality of average values of individual positional deviation quantities from the soldering position deviation data which indicate an average value of the positional deviation quantity for each individual substrate, and then compares a deviation value, which indicates a difference between a maximum value and a minimum value of the average values of the individual positional deviation quantities, with tolerance values predetermined in advance, and carries out a calculation for supplying feedback data, by which a mean value of the maximum value and the minimum value is obtained, if the deviation value is less than or equal to the tolerance value, and the data updating portion updates the positioning parameters based on the mean value.