JPS57116669A - Heating and controlling method in heat sensitive printer - Google Patents

Abstract

PURPOSE:To maintain excellent printing quality, by computing a record compensating value adding heat storing coefficient at each time point of the past execution of printing, obtaining external temperature compensating value from ambient temperature, and controlling the heating quantity of a resistor heating body based on the sum of both compensating values. CONSTITUTION:It is assumed that the heat storing coefficient A corresponding to the heat stored in a resistor heating body at one printing is exponentially decreased. The heat storing coefficient A is stored in a memory A. Printing record table F, wherein the execution or non-execution of the printing is stored, is provided. Meanwhile, the external temperature compensating value SB corresponding to the ambient temperature 26 is also stored in the memory 21 beforehand as a value which affects the heating quantity of the resistor heating body 24. When a priting command is given, the ambient temperature is read from the output of an AD converter 25, the external temperature compensating time SB is read from a CPU20, current conduction time is computed, and the printing instruction is outputted to a control circuit 22 so that a current is conducted to the resistor printing body 24 only during this time period and the printing is performed. In this method, the character type of a thermal printing head is heated, and printing with the constant concentration is always performed.