Printing apparatus and printhead control method
AssigneeCanon Kabushiki Kaisha
InventorsTakashi Sato, Joji Nagahira
Life of this patent
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Abstract
In a printing apparatus in which printing is performed by a printhead having a plurality of printing elements each driven by electrical energy, wherein the number of printing elements driven at the same time is changed depending upon the print data, the timing at which the number of printing elements driven simultaneously increases by a large amount is detected by using M bits of drive data transferred first in serially transferred N bits of drive data, and the electrical energy supplied to the printhead is increased before this timing.
Claims8
A printing apparatus for performing printing using a printhead having a plurality of printing elements, comprising:
- means for inputting print data;
- converting means for converting print data to drive data corresponding to the printing elements;
- transfer means for transferring the drive data to the printhead in a serial format in units of N bits at a time;
- driving means for driving the printing elements based upon the drive data;
- counting means for counting M-bits of data transferred first among the drive data in synchronism with transfer of the drive data by said transfer means, where N>M;
- detecting means for detecting an increase in the value of a count obtained by said counting means;
- and
- voltage generating means for outputting a voltage that drives the printing elements;
- wherein if said detecting means has detected an increase in the value of the count, said voltage generating means raises the output voltage before said driving means performs drive based upon drive data transferred next.
A printing apparatus for performing printing using a printhead having a plurality of printing elements, comprising:
- means for inputting print data;
- converting means for converting print data to drive data corresponding to the printing elements;
- transfer means for transferring the drive data to the printhead a prescribed number of bits at a time;
- driving means for driving the printing elements based upon the drive data;
- first detecting means for detecting amount of power load of printing elements driven simultaneously, based upon the drive data transferred by said transfer means;
- second detecting means for detecting an increase in amount of power load;
- and
- voltage generating means for outputting a voltage that drives the printing elements;
- wherein if said second detecting means has detected an increase in the amount of power load, said voltage generating means raises the output voltage before said driving means performs drive based upon drive data transferred next.
A method of controlling a printing apparatus for performing printing by a printhead having a plurality of printing elements each driven by electrical energy, the number of printing elements driven simultaneously being changed in accordance with drive data, said method comprising:
- a transfer step of transferring drive data to the printhead in a serial format in units of N bits at a time;
- a counting step of counting M-bits of data transferred first among the transferred drive data, where N>M;
- a determination step of determining whether the number of simultaneously driven printing elements has increased greatly, based upon a count value regarding print data that has been transferred previously and a count value regarding drive data to be transferred later;
- and
- an energy increasing step of increasing electrical energy, which is supplied to the printhead, before the printhead is driven by drive data to be transferred later, if it has been determined that the number of simultaneously driven printing elements has increased greatly.
Dependencies are inferred from the claim text.