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US 7,254,731 B2Granted
Image forming apparatus having an improved power-mode switching function
AssigneeRicoh Company, Ltd.
InventorKazuhiro Satoh
Life of this patent
Estimating the term…
Abstract
An image forming device having a communication unit includes a system control unit which controls the entire image forming apparatus, the system control unit having a CPU that is set in one of a normal mode, a power-saving mode and a sleep mode by controlling a power supply unit. A real-time clock keeps track of hours, minutes and seconds of a current time and outputs a signal indicating the current time. A register stores a return time that indicates a time the CPU is to be switched from one of the power-saving mode and the sleep mode to the normal mode. A comparator compares the current time of the clock with the return time of the register, and outputs, when a match occurs, a control signal to the CPU so that the CPU is switched to the normal mode.
Claims20
An electrical device having a communication unit, the electrical device comprising:
- a system control unit controlling the entire electrical device, the system control unit having a CPU that is set in one of a normal mode and a power-saving mode by controlling a power supply unit, wherein, when the CPU is set in the normal mode, a power output from the power supply unit is supplied to electrical components of the electrical device, and when the CPU is set in the power-saving mode, the power supplied to the electrical components in the normal mode is cut off or reduced and the electrical device is set in a standby state;
- a real-time clock keeping track of hours, minutes and seconds of a current time and outputting a signal indicating the current time;
- a register storing at least a return time that indicates a time the CPU is to be switched from the power-saving mode to the normal mode;
- a comparator comparing the current time output from the clock with the return time stored in the register, and outputting, when a match occurs, a control signal to the CPU so that the CPU is automatically switched from the power-saving mode to the normal mode;
- and
- a system memory which stores at least one time-specified operation data;
- wherein the system control unit comprises:
- a reading unit reading, when the time-specified transmission operation data is stored in the system memory, a time-specified operation with an earliest transmission time from the system memory;
- and
- a setting unit setting the earliest transmission time, read by the reading unit, into the register as the return time.
7 more elements
An electrical device having a communication unit, the electrical device comprising:
- a system control unit controlling the entire electrical device, the system control unit having a CPU that is set in one of a normal mode and a power-saving mode by controlling a power supply unit, wherein, when the CPU is set in the normal mode, a power output from the power supply unit is supplied to electrical components of the electrical device, and when the CPU is set in the power-saving mode, the power supplied to the electrical components in the normal mode is cut off or reduced and the electrical device is set in a standby state;
- a real-time clock keeping track of hours, minutes and seconds of a current time and outputting a signal indicating the current time;
- a register storing at least a return time that indicates a time the CPU is to be switched from the power-saving mode to the normal mode;
- a comparator comparing the current time output from the clock with the return time stored in the register, and outputting, when a match occurs, a control signal to the CPU so that the CPU is automatically switched from the power-saving mode to the normal mode;
- and
- a system memory which stores at least one time-specified operation data;
- wherein the system control unit comprises:
- a reading unit reading, when the time-specified transmission operation data is stored in the system memory, a time-specified operation with an earliest transmission time from the system memory;
- and
- a setting unit setting the earliest transmission time, read by the reading unit, into the register as the return time,
- wherein the system control unit sets into the register a second return time having a value smaller than a value of the return time originally specified, so that the CPU is switched to the normal mode completely when the originally specified return time is reached.
8 more elements
A method of controlling an electrical device having a communication unit, the electrical device comprising:
- a system control unit controlling the entire electrical device, the system control unit having a CPU that is set in one of a normal mode and a power-saving mode by controlling a power supply unit, wherein, when the CPU is set in the normal mode, a power output from the power supply unit is supplied to electrical components of the electrical device, and when the CPU is set in the power-saving mode, the power supplied to the electrical components in the normal mode is cut off or reduced and the electrical device is set in a standby state;
- a real-time clock keeping track of hours, minutes and seconds of a current time and outputting a signal indicating the current time;
- a register;
- a comparator;
- and a system memory storing at least one time-specified operation data, the method comprising the steps of:
- setting a return time in the register, the return time indicating a time the CPU is to be switched from the power-saving mode to the normal mode;
- causing the comparator to compare the current time output from the clock with the return time stored in the register, and to output, when a match occurs, a control signal to the CPU;
- reading, when the time-specified operation data is stored in the system memory, a time-specified operation with an earliest transmission time from the system memory;
- setting the earliest transmission time into the register as the return time;
- and
- switching the CPU to the normal mode when the comparator outputs the control signal to the CPU so that the CPU is automatically switched form the power-saving mode to the normal mode.
8 more elements
Dependencies are inferred from the claim text.