Printer

A printer comprising:

• a thermal head for transferring a plurality of color inks successively to paper so that a color image can be printed on the paper according to image data;
• battery power supply means;
• battery detecting means for conducting a current to a first load so as to detect a remaining battery capacity of said battery power supply means;
• display means for, when the remaining battery capacity detected by said battery detecting means is judged to be equal to or smaller than a battery capacity required for printing, displaying at least an indication of the fact;
• voltage detecting means for detecting a voltage developed from said battery power supply means;
• and
• control means for feeding power, which is supplied from said battery power supply means, to a second load smaller than said first load at the timing immediately preceding the transfer of the color inks to the paper, then instructing said voltage detecting means to detect the voltage, which is developed from said battery power supply means, at the predetermined timing immediately succeeding the feeding of power, and then performing correction according to the result of the detection so that a printing density of inks transferred from said thermal head will remain constant irrespective of whether the voltage developed from said battery power supply means is high or low.

A printer comprising:

• a thermal head for transferring a plurality of color inks successively to paper so that a color image can be printed on the paper according to image data;
• battery power supply means;
• voltage detecting means for detecting a voltage developed from said battery power supply means;
• and
• control means for feeding power, which is supplied from said battery power supply means, to a load at the timing immediately preceding the transfer of the color inks to the paper, then instructing said voltage detecting means to detect the voltage, which is developed from said battery power supply means, at the predetermined timing immediately succeeding the feeding of power, and then performing correction according to the result of the detection so that a printing density of inks transferred from said thermal head will remain constant irrespective of whether the voltage developed from said battery power supply means is high or low,
• wherein said voltage detecting means detects battery voltages respectively at different times under different load conditions for said batter power supply means prior to commencing a print operation, and
• wherein said control means calculates a printing ratio defined by the thermal energy generated by the load based on the number of loads activated simultaneously and the voltages detected by said voltage detecting means and controls power application duration of the load in accordance with the printing ratio.

A printer comprising:

• a thermal head for transferring a plurality of color inks successively to paper so that a color image can be printed on the paper according to image data;
• battery power supply means;
• voltage detecting means for detecting a voltage developed from said battery power supply means;
• and
• control means for feeding power, which is supplied from said battery power supply means, to a load at the timing immediately preceding the transfer of the color inks to the paper, then instructing said voltage detecting means to detect the voltage, which is developed from said battery power supply means, at the predetermined timing immediately succeeding the feeding of power, and performing correction according to the result of the detection so that a printing density of the inks transferred from said thermal head will remain constant irrespective of whether the voltage developed from said battery power supply means is high or low,
• wherein when the voltage detected by said voltage detecting means is a first voltage, the correction performed by said control means results in printing at a maximum density.

A printer comprising:

• a thermal head having a plurality of heating elements arranged therein in order to print a color image on paper according to image data;
• first correction value determining means for calculating a printing ratio relative to each gray-scale level specified in image data representing one line, and determining a correction value according to calculated printing ratios;
• second correction value determining means for performing an arithmetic operation using all gray-scale data items, based on which said all heating elements are heated for printing one line according to the image data, and determining a second correction value according to the result of the arithmetic operation;
• and
• control means for controlling the amounts of heat to be generated from said heating elements according to the correction values determined by said first and second correction value determining means.