# US 8,770,694 B2 · Printing element substrate and printhead

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- Number: US 8,770,694 B2
- Document ID: US8770694B2
- Status: Granted
- Kind: B2
- Application number: 13/493,214
- Filed: 2012-06-11
- Published: 2013-01-10
- Granted: 2014-07-08
- Earliest claimed: 2011-07-04
- Assignees: Canon Kabushiki Kaisha
- Applicants: Kengo Umeda
- Inventors: Kengo Umeda
- Web page: https://patentgrep.com/patent/US8770694B2

## CPC

- B41J 2/0455: {Details of switching sections of circuit, e.g. transistors}
- B41J 2/04541: {Specific driving circuit}
- B41J 2/04555: {detecting current}
- B41J 2/0457: {Power supply level being detected or varied}
- B41J 2/04573: {Timing; Delays}
- B41J 2/0458: {controlling heads based on heating elements forming bubbles}
- B41J 2002/14491: {Electrical connection}
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

A printing element substrate, including a printing element, a switching element which drives the printing element based on an input control signal, a first current source which generates a predetermined current, a second current source which generates a current based on an input voltage, and a current generation circuit which generates the control signal by amplifying a current obtained by adding a current generated by the second current source to a current generated by the first current source, and then generates the control signal by amplifying a current generated by the first current source.

## Claims

### Claim 1

A printing element substrate comprising:
a printing element;
a switching element which drives said printing element based on an input control signal;
a first current source which generates a predetermined current;
a second current source which generates a current based on an input voltage;
a current generation circuit which generates the control signal by amplifying a current obtained by adding a current generated by said second current source to a current generated by said first current source, and then generates the control signal by amplifying a current generated by said first current source;
a first signal line which supplies a current from said printing element to said switching element;
a second signal line which supplies a reference voltage;
a third signal line which supplies the voltage of said first signal line to said second current source; and
a first switch which is inserted in said third signal line and switches said third signal line between connection and disconnection based on a driving signal for designating driving of said printing element,
wherein said first switch is controlled to a connected state when the driving signal for designating driving of said printing element is active and a disconnected state when the driving signal for designating driving of said printing element is inactive.

### Claim 2 (depends on 1)

The substrate according to claim 1, wherein said switching element includes a transistor including an input which receives the control signal.

### Claim 3 (depends on 1)

The substrate according to claim 1, wherein said current generation circuit amplifies a current based on the input voltage.

### Claim 4 (depends on 1)

The substrate according to claim 1, further comprising:
a plurality of printing elements; and
a plurality of switching elements which are arranged in correspondence with said respective printing elements,
wherein said current generation circuit supplies the control signal to said plurality of switching elements.

### Claim 5 (depends on 1)

The substrate according to claim 1, wherein said current generation circuit receives an instruction signal for designating switching of an operation between activation and inactivation.

### Claim 6 (depends on 5)

The substrate according to claim 5, wherein the instruction signal includes a heat enable signal which defines a period of time for driving said printing element.

### Claim 7 (depends on 5)

The substrate according to claim 5, wherein the instruction signal includes a signal generated based on a logical product of a data signal which defines a printing element that is to perform a printing operation, and a heat enable signal which defines a period of time for driving said printing element.

### Claim 8 (depends on 1)

A printhead comprising a printing element substrate defined in claim 1.

### Claim 9

A printing element substrate comprising:
a printing element;
a switching element, including a transistor including an input which receives an input control signal, which drives said printing element based on the control signal;
a first current source which generates a predetermined current;
a second current source which generates a current based on an input voltage;
a current generation circuit which generates the control signal by amplifying a current obtained by adding a current generated by said second current source to a current generated by said first current source, and then generates the control signal by amplifying a current generated by said first current source;
a fourth signal line which connects the input and ground; and
a second switch which switches said fourth signal line between connection and disconnection based on a driving signal for designating driving of said printing element,
wherein said second switch is controlled to a connected state when the driving signal for designating driving of said printing element is inactiveand a disconnected state when the driving signal for designating driving of said printing element is active.