Thermal head drive circuit
First Claim
1. A thermal head drive circuit with an input connected to a source of printing data, and an output connected to a thermal head including individually actuatable and heatable heater elements, for printing successive lines comprising:
- a. a pulse-applying circuit having an input and an output, the output of said pulse-applying circuit being connected to the input of said thermal head, and the input of said pulse-applying circuit receiving pulse energy signals for applying printing pulse energy data to said thermal head;
b. storage means having an input and an output, the printing data from said printing source being successively read line by line into the input of said storage means;
c. an arithmetic heat accumulation state operator having an input and an output, the input of said operator being connected to the output of said storage means;
d. a pulse interval detector having an input and an output for detecting the time interval from termination of printing of a previously printed line to initiation of printing of the line next to be printed;
e. a memory having an input and an output for storing the pulse energy signals used in printing said previously printed line; and
f. pulse energy operator means having inputs and an output for determining the pulse energy signals to be applied to each of said heater elements for said line next to be printed, the inputs of said pulse energy operator means being connected to the outputs of said arithmetic heat accumulation state operator, said memory and said pulse interval detector, and the output of said pulse energy operator means being connected to the input of said pulse-applying circuit.
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Accused Products
Abstract
A thermal head drive circuit with the input connected to a source of printing data and the output connected to a thermal head including heater elements, so as to improve the printing quality of a thermal head recording apparatus for printing successive lines. Improved printing quality is effected by using data from previously printed lines to compute a corrected pulse energy for the line being printed. The circuit uses a heat accumulation state operator for computing the heat storage state of each of the heater elements constituting a thermal head, a pulse energy operator for computing a printing pulse energy to be applied to each of the heater elements, a memory for storing the electrical pulse energy used in the previously printed line, and either a pulse interval detector for detecting a time interval from a termination of printing of a previously printed line, or a temperature detector for detecting an internal-temperature of a thermal head. The pulse energy operator uses data from the heat accumulation state operator, from the memory which has data on the pulse energy used in previously printed lines, and from either the pulse interval detector or the temperature detector. The output of the pulse energy operator is connected to a pulse applying circuit which is used to drive the heater elements of a thermal head.
28 Citations
20 Claims
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1. A thermal head drive circuit with an input connected to a source of printing data, and an output connected to a thermal head including individually actuatable and heatable heater elements, for printing successive lines comprising:
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a. a pulse-applying circuit having an input and an output, the output of said pulse-applying circuit being connected to the input of said thermal head, and the input of said pulse-applying circuit receiving pulse energy signals for applying printing pulse energy data to said thermal head; b. storage means having an input and an output, the printing data from said printing source being successively read line by line into the input of said storage means; c. an arithmetic heat accumulation state operator having an input and an output, the input of said operator being connected to the output of said storage means; d. a pulse interval detector having an input and an output for detecting the time interval from termination of printing of a previously printed line to initiation of printing of the line next to be printed; e. a memory having an input and an output for storing the pulse energy signals used in printing said previously printed line; and f. pulse energy operator means having inputs and an output for determining the pulse energy signals to be applied to each of said heater elements for said line next to be printed, the inputs of said pulse energy operator means being connected to the outputs of said arithmetic heat accumulation state operator, said memory and said pulse interval detector, and the output of said pulse energy operator means being connected to the input of said pulse-applying circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 20)
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11. A thermal head drive circuit with an input connected to a source of printing data, and an output connected to a thermal head including individually actuatable and heatable heater elements, for printing successive lines comprising:
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a. a pulse-applying circuit having an input and an output, the output of said pulse-applying circuit being connected to the input of said thermal head, and the input of said pulse-applying circuit receiving pulse energy signals for applying printing pulse energy data to said thermal head; b. storage means having an input and an output, the printing data from said printing data source being successively read line by line into the input of said storage means; c. an arithmetic heat accumulation state operator having an input and an output, the input of said operator being connected to the output of said storage means; d. a temperature detector having an input and an output for detecting an internal temperature in said thermal head; e. a memory having an input and an output for storing the pulse energy signals used in printing the line immediately previously printed; and f. pulse energy operator means having inputs and an output for determining the pulse energy signals to be applied to each of said heater elements for said line next to be printed, the inputs of said pulse energy operator means being connected to the outputs of said arithmetic heat accumulation state operator, said memory and said temperature detector, and the output of said pulse energy operator means being connected to the input of said pulse-applying circuit. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification