Thermal printer with minimized power difference between sequentially driven blocks of printing elements
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorsKiyoshi Negishi, Katsumi Kawamura, Katsuyoshi Suzuki, Hiroshi Orita, Minoru Suzuki
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Abstract
A thermal printer has a thermal head provided with a plurality of thermal elements arranged linearly. The thermal printer also includes a power source capable of supplying a predetermined power level to the plurality of thermal elements which generate heat, a drive for driving the thermal elements with power, and a controller for dividing the plurality of thermal elements into at least two groups. The grouping of the thermal elements is determined such that a difference in power consumption between the groups is minimized.
Claims8
A thermal printer having a thermal head provided with a plurality of linearly arranged thermal elements, said printer comprising:
- a power source capable of supplying power of a predetermined power level to the plurality of thermal elements, the plurality of thermal elements being divided into a predetermined number of blocks, each of the blocks having a similar number of thermal elements;
- a driver for driving the thermal elements with power supplied by the power source, in accordance with printing data, said thermal elements generating heat when driven by said driver;
- and
- a controller for dividing the plurality of thermal elements into at least two groups when the thermal elements are driven, said controller determining the at least two groups of thermal elements such that a difference in power consumption between the at least two groups is minimized, said controller determining the number of said thermal elements to be simultaneously driven in each of said blocks based upon said printing data, said controller combining said predetermined number of blocks to form said at least two groups such that a difference in said number of said thermal elements to be simultaneously driven in each group is minimized, said controller dividing said plurality of thermal elements into first, second, third and fourth linearly and sequentially arranged blocks, said controller determining which of said first and fourth blocks has a lesser number of thermal elements to be driven, and which of said second and third blocks has a greater number of thermal elements to be driven, said controller combining said block having said greater number of thermal elements to be driven and said block having said lesser number of thermal elements to be driven into one of said at least two groups;
- said driver driving said groups at different time intervals.
A thermal printer having a thermal head provided with a plurality of thermal elements that print data on a sheet, said thermal printer comprising:
- a battery for supplying a predetermined voltage;
- a driver for driving said plurality of thermal elements simultaneously by applying said predetermined voltage of the battery to said plurality of thermal elements;
- and
- a controller for determining a number of thermal elements to be driven in accordance with said printing data, and controlling said driver to vary a period of time during which said driver applies said predetermined voltage to said plurality of thermal elements in accordance with said number of thermal elements to be driven, said period of time being determined in accordance with the relationship:
- t=T+A.multidot.n/N
- wherein t represents the period of time, T and A are constants, n represents the number of thermal elements to be driven, and N represents the number of the plurality of thermal elements.
A method of driving a plurality of thermal elements on a thermal head of a thermal printer, said thermal elements being linearly arranged, said method comprising:
- dividing said plurality of thermal elements into a plurality of blocks, each of said plurality of blocks having a similar number of thermal elements;
- determining a number of said thermal elements to be driven simultaneously in accordance with printing data;
- combining said plurality of blocks into at least two groups such that a difference in a number of said thermal elements to be simultaneously driven in each group is minimized, said combining of said plurality of blocks into at least two groups comprising determining which block, of a pair of blocks located at linear ends of said plurality of blocks has a lesser number of thermal elements to be driven, and determining which block of a pair of blocks located between said pair of blocks located at linear ends of said plurality of blocks has a greater number of thermal elements to be driven, and combining said block determined to have said greater number of thermal elements to be driven simultaneously and said block determined to have said lesser number of thermal elements to be driven simultaneously into one of said groups;
- and
- driving said groups at different time intervals.
A thermal printer having a thermal head provided with a plurality of thermal elements that print data on a sheet, said thermal printer comprising:
- a battery having an operating voltage which fluctuates depending on a load applied to said battery;
- a driver for driving said plurality of thermal elements simultaneously in accordance with printing data, by applying said operating voltage of said battery;
- a controller for evaluating power consumption when a previous line of an image was printed, and controlling said driver to vary a period of time during which said driver applies said operating voltage to said plurality of thermal elements for a current line, in accordance with said power consumption evaluated by said controller, said controller comprising a voltage detector for detecting a first voltage of said battery when printing has not been executed and a second voltage of said battery when printing has been executed.
Dependencies are inferred from the claim text.