Controller for density of printing of thermal printer

Abstract

Abstract PURPOSE:To keep the optimum density of printing at all times by continually controlling head driving pulse-width at an optimum value in response to the temperature change of a head, the resistance value of the head and the set value of volume for adjusting the density of printing. CONSTITUTION:Set voltage D for volume 50 for adjusting density and output voltage E from a head-temperature detecting thermistor 61 through AD converters 42 and codes F, G at two bits from a head resistance-value grade code generating circuit through an input port are each inputted to a CPU40. Head-temperature digital data DH and density-volume digital data DD refer to a temperature-pulse width converting table and a density pulse-width converting table for an ROM and are converted into width data TH, TD at two bytes and a grade code DR into width data TR, all are added together with a width-data fixed value TF and width data TT is decided, and a heating resistor is driven through a counter timer.

Inventors

• 👤 Shuji Fujii
• 👤 藤井　修司

Bibliographic Details