JP2004005029A - Device having power saving function and power saving control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further reduce power consumption in energy-saving mode. <P>SOLUTION: In an image forming device operable in a general operation mode and in an energy saving mode limited in power supply, a main CPU 101 executes various controls in the general operation mode. A sub-CPU 104 is smaller in power consumption than the main CPU 101. In the energy-saving mode, the power supply to a non-night power supply system including the main CPU 101 is interrupted, while the power supply to a night power supply system related to the sub-CPU 104 is retained. When a release instruction is issued from the sub-CPU 104 according to data receipt from a network interface 108 or FAX interface, prescribed operation input from an operation part 107, or the like, a power supply control part 111 releases the energy-saving mode and restarts the power supply to the non-night power system including the main CPU 101. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus having a power saving function and a power saving control method for reducing power supply by, for example, turning off power supply to each unit that does not perform a function in a standby state in order to reduce power consumption.
[0002]
[Prior art]
In recent years, OA equipment has been increasing in scale. Particularly in an image forming system such as a copying machine, the scale of the system has been remarkably increased due to complex functions and various types of image processing and printing processing. It is. Therefore, in a control unit for controlling such an image forming system, a DRAM having a capacity of several hundred megabytes has been required as a buffer for image processing, mainly for a high-speed, high-performance CPU. . Further, in order to store images and store system management information, a giga-unit auxiliary storage device such as a hard disk has become indispensable.
[0003]
On the other hand, in addition to the increasing energy-consciousness of users, the reduction of power consumption is also considered important in the above-mentioned image forming systems due to the Energy Conservation Law in Japan and legal regulations such as Energy Star and Blue Angel overseas. Is coming.
[0004]
Therefore, an image forming system incorporating the function of the energy saving mode has been produced. In the energy saving mode of the image forming system, power supplied to a portion that does not execute a function in a standby state is reduced. Specifically, processes such as lowering the temperature of the fixing roller, stopping the rotation of the polygon motor, and turning off the display on the operation panel are performed.
[0005]
[Problems to be solved by the invention]
However, in the conventional energy saving mode, only the load system such as the fixing roller, the polygon motor, and the operation panel is turned off, and the CPU and its peripheral circuits are kept on, which is not enough to reduce power consumption. Was. The reason why the CPU and its peripheral circuits are not turned off is that, for example, since it takes time to start up the hard disk, it takes time to return from the energy saving mode, and data from an external device such as a network or a facsimile is transmitted. There is a problem that reception cannot be performed.
[0006]
An object of the present invention is to solve the above-mentioned problem and further reduce power consumption in a power saving mode.
It is another object of the present invention to be able to return from the power saving mode without hindering the operation. In particular, it is an object of the present invention to ensure that received data can be processed when a return from the power saving mode is started due to external data reception or the like.
[0007]
[Means for Solving the Problems]
An apparatus having a power saving function according to the present invention for achieving the above object,
A device having a power saving function including a normal operation mode and a power saving mode in which power supply is limited,
A first control unit that includes a first CPU and controls various controls in a normal operation mode;
A second control unit that includes a second CPU that consumes less power than the first CPU and that issues an instruction to cancel the power saving mode in response to a predetermined input signal;
In the power saving mode, the power supply to the first control unit is cut off and the power supply to the second control unit is maintained, and the power saving mode is released in response to the release instruction from the second control unit. Power supply control means for restarting power supply to the first control unit.
[0008]
Further, a power saving control method according to the present invention for achieving the above object,
A power saving function with a normal operation mode and a power saving mode with a limited power supply,
A first control unit that includes a first CPU and controls various controls in a normal operation mode;
A second control unit that includes a second CPU that consumes less power than the first CPU and has a second control unit that issues an instruction to cancel the power saving mode in response to a predetermined input signal. ,
A first step of interrupting power supply to the first control unit in the transition to the power saving mode and maintaining power supply to the second control unit;
A second step of releasing the power saving mode in response to the release instruction from the second control unit and restarting power supply to the first control unit.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0010]
FIG. 1 is a block diagram illustrating the configuration of the image forming system according to the present embodiment. In FIG. 1, reference numeral 101 denotes a main CPU which controls the entire image forming system. In order to control the entire system, it is necessary to perform various processes at high speed, and therefore, it is necessary to use a high-performance and high-speed CPU. That is, the main CPU 101 is high-performance and high-speed, and has relatively large power consumption. Reference numeral 102 denotes a main work RAM connected to the main CPU 101, which is used for a buffer for performing image processing and for temporarily storing system management information.
[0011]
A hard disk 103 is used for storing system management information, storing images, and the like. It should be noted that the system management information is information such as various system-specific setting values representing the configuration and characteristics of each system, and the system cannot operate without such information.
[0012]
Reference numeral 104 denotes a sub CPU, which communicates with an operation unit (107) and external devices via a network interface (108) and / or a facsimile interface (109). A high-speed CPU is not required for communication with such an external device, and an inexpensive CPU with few functions can be used. That is, a CPU that consumes less power than the main CPU is used as the sub CPU 104.
[0013]
A BOOT-ROM 105 stores a system program. Reference numeral 106 denotes a sub work RAM connected to the sub CPU 104. Note that the RAM 102 and the RAM 106 can be realized without being physically separate from each other, but the separate units facilitate control.
[0014]
Reference numeral 107 denotes an operation unit, which includes a key input unit (nightly power supply system) for setting an instruction from a user and an LCD panel unit (emergency night power supply system) for displaying setting contents. . Note that power is supplied to the key input unit from a night power system that constantly supplies power. In addition, power is supplied to the LCD panel unit from an emergency night power supply system in which power supply is stopped in the energy saving mode.
[0015]
Reference numeral 108 denotes an interface unit with a device connected to the network, and 109 denotes an interface unit for performing FAX communication.
[0016]
An image processing unit 110 performs various image processing on image data. A power control unit 111 controls power supply from the power supply 114 to each unit of the system. Reference numeral 112 denotes a scanner unit that reads an image, and 113 denotes a printer unit that records an image on a recording medium such as paper. Reference numeral 114 denotes a power supply, which has two power supply systems, a nighttime power supply system and an emergency night power supply system, and supplies power to various parts of the system according to a signal from the power supply control unit 111.
[0017]
Next, the operation of the image forming system embodying the present invention will be described with reference to the flowcharts of FIGS.
[0018]
FIG. 2 is a flowchart for explaining the operation at the time of power-on. When the power switch of the image forming system is turned on (S201), first, power is supplied to the system components of the night power system (S202), and then power is supplied to the system components of the night power system (S203). . More specifically, the sub CPU 104 is activated in step S202, and power is supplied to the power supply system at night under the control of the sub CPU 104. With such an order, it is possible to easily take a countermeasure against a single power supply in an interface portion between the power supply system at night and the power supply system at night. In general, when there are two power sources, a night system and an emergency system, there is a state in which the night system is ON and the emergency system is OFF (single power supply state). Single power supply protection means that in the situation where a night-time device and an emergency night-time device are connected by a bus, the device does not break down due to a voltage higher than the specified value being applied to the device when it enters a single power supply state Means to take some kind of countermeasures. As a specific countermeasure, the output buffer of the night-time device connected to the night-time device should be provided with a mechanism capable of setting the output terminal to high impedance (Hi-Z) at the time of single power supply. Can be Further, the input buffer of the night-time device connected to the emergency night-time device may be subjected to pull-down processing. The reason why “easy to take a single power supply measure” can be as follows. In other words, by setting the power-on sequence in the order of night-night to night-night, three types of power states can be considered (“night-night is off and night-night is off”). ← → “Nighttime system is ON and emergency night system is OFF” ← → “Nighttime system is ON and emergency night system is ON”). Accordingly, there is one type of single power supply state, “the night system is ON and the emergency night system is OFF”. Therefore, the above single power supply countermeasures (the output terminal is set to Hi-Z) are taken. It only has to be performed, and it becomes easy to take countermeasures against single power supply.
[0019]
In the image forming system of the present embodiment, the main work RAM 102, the sub CPU 104, the BOOT-ROM 105, the sub work RAM 106, the LCD panel unit in the operation unit 107, the network interface unit 108, the FAX interface unit 109, and the power control unit 111 The main CPU 101, the hard disk 103, the image processing unit 110, the scanner unit 112, the printer unit 113, and the key input unit in the operation unit 107 are a night power system.
[0020]
When power is supplied to each part of the system, a BOOT is performed by the system program stored in the ROM 105, and the main CPU 101 and the sub CPU 104 are activated (S204). When the hard disk 103 starts up, the main CPU 101 reads out the system management information stored therein and expands the system management information in the main work RAM 102. As a result, the system components are initialized (S205).
[0021]
When the initialization of each part of the system is completed as described above, the system enters a standby state where image formation is possible (S206).
[0022]
Next, an operation of the image forming system of the present embodiment shifting from the standby state to the energy saving mode will be described. FIG. 3 is a flowchart illustrating an operation when shifting to the energy saving mode.
[0023]
When a predetermined time elapses after the image forming system completes a final job such as copying or printing (S301), a transition to the energy saving mode is started (S302). The predetermined time for determining the transition to the energy saving mode is arbitrary, and the user may be allowed to select, for example, 5 minutes or 2 hours as the predetermined time.
[0024]
During the energy saving mode, the RAM 102 performs self-refresh to hold the system management information and the like developed at the time of startup (S205) (S303). The self-refresh is a refresh method in a DRAM such as an SDRAM or a DDR, and is a method in which a small amount of power of several milliamps per chip is consumed in order to retain the stored contents in the chip. For example, in the case of a 256 MB-DIMM, although there is a difference depending on a maker or the like, the power consumption is about 1500 mA (about 5 W) in the normal refresh, whereas about 30 mA (about 0.1 W) in the self refresh. Thus, the power consumption can be extremely reduced. When shifting to the energy saving mode, the main CPU 101 and the sub CPU 104 exchange data, and in actuality, the RAM 102 shifts to self-refresh under the control of the main CPU 101 (because the RAM 102 is connected to the main CPU).
[0025]
The sub CPU 104 prepares for data reception from an external device such as a network or a facsimile. When the components of the system are ready, a command is issued to the power control unit 111, the power supply to the components of the night power system is stopped (S304), and the apparatus enters the energy saving mode (S305).
[0026]
At this time, the operation unit 107 keeps the power supplied to the key input unit in order to receive an instruction from the user to cancel the energy saving mode. Also, the power supply to the LCD panel is stopped to turn off the display.
[0027]
The transition to the energy saving mode by the image forming system according to the present embodiment has been described above. Next, a description will be given of a process in which the image forming system of the present embodiment returns from the energy saving mode to a normal state. In the present embodiment, the energy saving mode is canceled when the sub CPU 104 receives a predetermined input signal from the outside. In other words, the sub CPU 104 operates to release the energy saving mode based on data reception from an external device via the interface 108 or 109 and an operation signal input from the operation panel 107.
[0028]
FIG. 4 is a flowchart illustrating an operation of the image forming system according to the present embodiment when data is received from an external device during the energy saving mode.
[0029]
When data is received from an external device via the network interface 107 or the facsimile interface 108 during the energy saving mode (S401), recovery from the energy saving mode is started and holding of the received data in the RAM 106 is started (S402).
[0030]
When power is supplied to each part of the system of the emergency power supply system (S403), the main CPU 101 reads out the system management information stored in the main work RAM 102 (read from the hard disk in step S205 and expands it at the time of device startup). It is started by the system management information (S404). In this case, unlike when the power is turned on, the system management information stored in the hard disk 103 is not read and the process of expanding the system management information in the main work RAM 102 is not required, so that the system can be restored in a very short time. For example, it takes about 30 seconds to start up a hard disk, and only a few seconds to start up other parts. Then, since system management information is stored in the hard disk, each part of the system cannot start operation until the hard disk starts up, and it takes time to start up. According to the above configuration, each part of the system starts operation (start-up operation) based on the system management information expanded in the RAM 102, that is, the operation can be started without waiting for the start-up time of the hard disk. Therefore, it is possible to return from the energy saving mode in a very short time.
[0031]
The sub CPU 104 communicates with the external device, and stores the received data in the RAM 106 (S405). When the system components start up in this way, the received data is subjected to desired image processing to form an image (S406). Various methods can be considered for handling the data stored in the RAM 106 after the main CPU 101 has started up, and an example thereof will be as follows. When the main CPU 101 starts up, the data is transferred from the RAM 106 to the RAM 102, and the received data after the main CPU 101 starts up is directly stored in the RAM 102. That is, the sub CPU 104 may perform only the minimum receiving process in the energy saving mode, and may take over the receiving process to the main CPU 101 after the system is started.
[0032]
Although the process shown in FIG. 4 is performed when data is received from an external device, power is supplied to the power supply system at night even when an input is made from the operation unit 107. Also in this case, the main CPU 101 can quickly return using the system management information stored in the RAM 102.
[0033]
As described above, according to the present invention, it is possible to eliminate the problem that data cannot be received from an external device such as a network or a facsimile during the energy saving mode, and to simply stop power supply to a conventional load system. Power supply to a large-scale main CPU that controls the entire system can be stopped, so that power consumption can be further reduced compared to the conventional case where only the load system is turned off. Can be.
[0034]
Note that the RAM 102 and the RAM 106 may be a common RAM. Further, as the image forming system of the present embodiment, a function as a printer that prints out according to an instruction from an external device through the network interface 108 or a facsimile apparatus that prints out FAX data received from the FAX interface 109 (in this case, A multifunction copier having a function of transmitting an image read by the scanner unit 112 as FAX data) has been described, but a single function device (copier, printer, FAX device) has been described. Obviously, it may be. Further, the portion of the power saving device of the present embodiment in which the main CPU and the sub CPU are combined can be applied to an apparatus other than the image forming apparatus.
[0035]
The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but it can be applied to a device including one device (for example, a copier, a facsimile device, etc.). May be applied.
[0036]
【The invention's effect】
As described above, according to the present invention, it is possible to further reduce power consumption in the power saving mode.
Further, according to the present invention, it is possible to return from the power saving mode without hindering the operation. In particular, when the return from the power saving mode is started due to external data reception or the like, the received data can be reliably processed.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an image forming system according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an operation at power-on.
FIG. 3 is a flowchart illustrating an operation when shifting to an energy saving mode.
FIG. 4 is a flowchart illustrating an operation when data is received from an external device during the energy saving mode.

Claims (10)

A device having a power saving function capable of operating in a normal operation mode and a power saving mode in which power supply is restricted,
A first control unit that includes a first CPU and controls various controls in a normal operation mode;
A second control unit that includes a second CPU that consumes less power than the first CPU and that issues an instruction to cancel the power saving mode in response to a predetermined input signal;
In the power saving mode, the power supply to the first control unit is cut off and the power supply to the second control unit is maintained, and the power saving mode is released in response to the release instruction from the second control unit. A power control unit for restarting power supply to the first control unit. The second control unit includes:
A memory connected to the second CPU,
Issue the release instruction in response to data reception from an external device,
2. The device having a power saving function according to claim 1, wherein data received at least until the first control unit starts up by restarting power supply is held in the memory. 3. The first control unit has an auxiliary storage device connected to the first CPU and storing system management information necessary for starting up the system at power-on,
The memory of the second control unit has a memory area for use by the first CPU, and system management information is stored in the memory area during operation of the first CPU;
When the power supply to the first control unit is restarted by the power control unit, the first CPU resumes its operation using system management information stored in the memory area. The device having the power saving function according to claim 2. The apparatus according to claim 2, wherein the predetermined input signal is print data received from an external apparatus via a network. The device having a power saving function according to claim 2, wherein the predetermined input signal is a facsimile signal received via a line. A normal operation mode, and a power saving function that enables operation in a power saving mode in which power supply is restricted,
A first control unit that includes a first CPU and controls various controls in a normal operation mode;
A second control unit that includes a second CPU that consumes less power than the first CPU and has a second control unit that issues an instruction to cancel the power saving mode in response to a predetermined input signal. ,
A first step of interrupting power supply to the first control unit in the transition to the power saving mode and maintaining power supply to the second control unit;
A second step of releasing the power saving mode in response to the release instruction from the second control unit and restarting power supply to the first control unit. The second step includes:
Issuing the release instruction in response to data reception from an external device,
7. The power saving control according to claim 6, further comprising: holding at least data received until the first control unit starts up by restarting power supply, in a memory of the second control. Method. The first control unit has an auxiliary storage device connected to the first CPU and storing system management information necessary for starting up the system at power-on,
A step of storing system management information in a memory of the second control unit while the first CPU is operating;
When power supply to the first control unit is restarted in the second step, the first CPU resumes its operation using system management information stored in the memory area. The power saving control method according to claim 7. The power saving control method according to claim 7, wherein the predetermined input signal is print data received from an external device via a network. The power saving control method according to claim 7, wherein the predetermined input signal is a facsimile signal received via a line.

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