JP2000353032A - Peripheral equipment with power saving function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively and efficiently execute power saving. SOLUTION: When both interfaces of USB and IEEE 1394 exist in data communication between a host device and a printer, both interfaces are monitored by a CPU and enters in an power saving mode according to a communicating state in the interfaces. Potentials of power supply lines of cables of the USB and the IEEE 1394 are detected whether they are equal to or lower than a normal value or not (a step S8) and when both potentials are equal to or lower than the normal value (yes in S8), the printer is set in the power saving mode (S11) by the CPU. When at least the potential of a power line of one cable is normal (no in S8) and when the IEEE 1394 is normal next, a packet is transmitted to the host device through the IEEE 1394, in addition, when the USB is normal, a USB chip is checked whether it is in a sleep mode or not (S9) and when no ACK signal is returned from the host device and the USB chip is in the sleep mode (yes in S10), the printer 3 is set in the power saving mode (S11).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a peripheral device of a host device such as a printer having a power saving function, and more particularly to a technique for causing a peripheral device to enter a power saving state.

[0002]

2. Description of the Related Art Generally, a peripheral device such as a printer having a power saving function executes power saving when access from a host device does not come for a predetermined time.

[0003]

For example, a laser printer consumes a relatively large amount of power even in a printing standby state, so it is desirable to effectively and efficiently save power. However, the printer enters the power saving state only when the access from the host device does not come for a certain period of time as described above, and in a laser printer, the above time is set longer (for example, 30 minutes) due to the function. Is done. This is a problem from the viewpoint of promoting energy saving.

Accordingly, it is an object of the present invention to effectively and efficiently perform power saving.

[0005]

A peripheral device according to a first aspect of the present invention is a peripheral device connected to a host device via a communication interface having a power line, and a potential of a power line of the communication interface. And power saving execution means for executing power saving of the peripheral device when the potential of the power supply line becomes equal to or lower than a specified value.

[0006] In a preferred embodiment, the communication interface is USB or IEEE1394. The potential of the power supply line of the USB or IEEE 1394 interface becomes lower than a specified value when data communication cannot be performed. That is, it is possible to detect whether or not data communication is possible by checking whether or not the potential is equal to or less than a specified value. If the potential is equal to or less than the specified value, data communication is not possible. Therefore, power saving is executed in order to save power consumption in waiting for data processing.

A peripheral device according to a second aspect of the present invention is a peripheral device connected to a host device via a communication interface capable of indicating the presence or absence of bus activity of the host device. There is provided a detecting means for detecting whether or not there is no bus activity, and a power saving executing means for executing power saving of the peripheral device when it is detected that there is no bus activity.

[0008] In a preferred embodiment, the communication interface is a USB. In this case, the detecting means is a USB
The presence or absence of bus activity is detected based on whether the chip is in the sleep mode.

A peripheral device according to a third aspect of the present invention is a peripheral device connected to a host device via a communication interface in which a data receiving side returns an acknowledgment signal to a data transmitting side. There is provided a data transmission unit for transmitting data to the host device, and a power saving execution unit for executing power saving of the peripheral device when no acknowledgment signal is returned from the host device in response to data transmission.

For example, in data communication in IEEE 1394, when the host device enters a sleep state,
Even if a packet is received from an external device (for example, a peripheral device)
The CK signal is not sent. That is, if a packet is transmitted to the host device and no ACK signal is returned, the host device is in the sleep state. In such a case, the power saving execution unit executes the power saving.

In a preferred embodiment, the peripheral device according to the first to third aspects further includes a request receiving unit that receives a power saving execution request from a user. Then, the power saving execution unit executes the above power saving when recognizing the power saving execution request from the user. The request receiving means may be a power saving ON / OFF switch or a user instruction through a graphic interface.

In a preferred embodiment, the peripheral device with a power saving function according to the first to third aspects is a printer.
More preferably, it is a laser printer.

[0013]

FIG. 1 shows the configuration of a printer according to an embodiment of the present invention.

The printer includes a control panel (hereinafter, panel) 1 for allowing a user to input various settings and inform the user of the status of the printer, and a print engine 3 for hard-copying and distributing a print image. A print controller 5 that interprets print job data received from a host device (not shown), creates print image data in accordance with the various settings or settings specified by the host device, and sends the print image data to the print engine 3. Print controller 5
Are an interface circuit (hereinafter, I / F) 7 for communicating with the host device and the panel 1, an image processing circuit 9,
An M11, a ROM 13, a CPU 15, and a mechanical controller (hereinafter, mechanical controller) 17 are provided.

The I / F 7 controls communication with the panel 1 or the host device. That is, the I / F 7 stores the setting information from the panel 1 in the RAM, passes the print job data from the host device to the image processing circuit or the CPU, and transmits a packet (for example, status Information). The I / F 7 is a USB, I / F as a host interface to the host device.
IEEE1394, IEEE1284 (parallel), RS-
It has an interface of all of various standards such as 232C (serial), Macintosh serial, and Ethernet, or at least a USB or IEEE 1394 standard.

The image processing circuit 9 performs image processing such as color conversion and binarization on the image data included in the print job data from the I / F 7 and stores it in a print buffer in the RAM 11. Hand over to mechanical control 17.

The RAM 11 is used as a receiving buffer for temporarily storing print job data from the host device, a print buffer for storing image processing data from the image processing circuit 9, a work area for the CPU 15, and the like.

The ROM 13 stores programs for the CPU 15, fixed data, and the like.

The CPU 15 performs overall control and error processing. CPU 15 also performs power saving control according to the present invention.

The mechanical controller 17 sends the print image from the image processing circuit 9 to the print engine 3, and drives and controls the print engine 3.

The printer 3 which performs the printing process according to the above-described configuration has a power saving function for saving power consumption in the printing standby state as one of the processes executed by the CPU 15, and the state of the host device and the communication. The power saving mode is entered according to the situation, the user's request, and the like to execute power saving. Hereinafter, several methods for entering the power saving mode will be described.

The first method is a case where the host interface has a USB interface and no IEEE 1394 (or a case where both the USB and the IEEE 1394 interfaces are used and it is known in advance that only the USB interface is used). ), CPU 15
Monitors the USB interface and enters a power saving mode according to the communication status at the USB interface. This will be described with reference to FIG.

If the USB hub interposed between the host device and the printer 3 breaks down or the USB cable is disconnected, or the like, and the communication state is hindered, the potential of the power supply line of the USB interface falls below a specified value. become. At this time,
The host device and the printer 3 are in a state where data cannot be transmitted / received to / from each other via the USB cable. Therefore,
The CPU 15 constantly or periodically monitors the potential of the power supply line of the USB cable and checks whether or not the potential is equal to or lower than a specified value (step S1). If the value is equal to or smaller than the specified value (Yes in S1), the printer 3 is set to the power saving mode.
(S3).

In data communication by USB, when the host device goes into a sleep state or the like and there is no bus activity, the USB chip enters a power saving mode (sleep mode). Also at this time, there is no possibility that the printer 3 receives print job data from the host device. Therefore,
If the potential of the power supply line is normal in step S1 (no in S1), the CPU 15 detects whether the USB chip is in the power saving mode (S2), and if the USB chip is in the power saving mode, (Yes in S2), the printer 3 is set to the power saving mode (S3).

The second method is to use the CPU 15 if the computer has an IEEE 1394 interface and no USB interface (or if both the USB and the IEEE 1394 interfaces are used and it is known in advance that only the IEEE 1394 interface is used). Is I
It is to monitor the EEE1394 interface and enter a power saving mode according to the communication status at the interface. This will be described with reference to FIG.

The potential of the power supply line of the cable of the IEEE 1394 interface (hereinafter, the IEEE 1394 cable) becomes the specified value or less, similarly to the potential of the power supply line of the USB cable, when the communication state is disturbed due to disconnection of the cable or failure of the hub. . At this time, the host device and the printer 3
It is in a state where data cannot be transmitted / received to / from each other by the EE1394 cable. Therefore, the CPU 15 constantly or periodically monitors the potential of the power supply line of the IEEE 1394 cable and checks whether the potential is equal to or lower than a specified value (step S4). If it is less than the specified value, (S
Then, the printer 3 is set to the power saving mode (S7).

In the IEEE 1394 data communication, when the host device is in the sleep state, the printer 3
Will not return an ACK (acknowledgement) signal even if it receives a packet (eg, status information) from At this time, there is no possibility that the printer 3 receives the print job data. Therefore, if the potential of the power supply line is normal in step S4 (No in S4), the CPU 15 transmits a packet to the host device (S5), and the host device
When the CK signal is not returned (Yes in S6), the printer 3 is set to the power saving mode (S7).

The third method uses USB and IEEE139.
4 if both interfaces exist.
Monitors both interfaces, and enters a power saving mode according to the communication status between them. about it,
This will be described with reference to FIG.

The CPU 15 is connected to USB and IEEE 139.
It is detected whether or not the potential of the power supply line of the cable No. 4 is below a specified value (step S8).
(Yes in S8), the printer 3 is set to the power saving mode (S1
1). If the potential of the power line of at least one of the cables is normal (no in S8), then, if the IEEE1394 is normal, a packet is transmitted to the host device through the IEEE1394, and if the USB is normal, the USB chip is in the sleep mode. Check if it has not entered (S9),
No ACK signal returned from host device and USB
If the chip is in sleep mode (yes in S10)
s), the printer 3 is set to the power saving mode (S11).

A fourth method is to provide an ON / OFF switch (hereinafter, a power saving switch) for turning the printer 3 into a power saving mode on the panel 1. In this case, when the power saving switch is turned on by the user, as shown in FIG. 5, the CPU 15 detects the power saving switch ON via the I / F 7 (yes in S12), and sets the printer 3 to the power saving mode (S13). ).

As described above, the printer 3 includes a host device,
The power saving mode can be entered according to the communication status and the user's request. As a result, power can be effectively and efficiently saved, contributing to energy saving. This is particularly effective for a laser printer that consumes relatively large power even in a printing standby state.

Although some preferred embodiments of the present invention have been described above, these are merely examples for describing the present invention, and are not intended to limit the scope of the present invention only to these examples. . The present invention is not limited to the printer 3 shown in FIG.
It can be implemented with various printers. Further, the present invention is applicable not only to printers but also to other types of peripheral devices.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a printer according to an embodiment of the present invention.

FIG. 2 shows a CP when entering a power saving mode according to the first method.
9 is a flowchart showing the operation of U.

FIG. 3 shows a CP when entering a power saving mode according to the second method.
9 is a flowchart showing the operation of U.

FIG. 4 shows a CP when entering a power saving mode according to a third method.
9 is a flowchart showing the operation of U.

FIG. 5 shows a CP when entering a power saving mode according to a fourth method.
9 is a flowchart showing the operation of U.

[Explanation of symbols]

 Reference Signs List 1 control panel 3 print engine 5 print controller 7 interface circuit 9 image processing circuit 11 RAM 13 ROM 15 CPU 17 mechanical controller

Claims (10)

[Claims] 1. A peripheral device connected to a host device via a communication interface having a power supply line, a monitoring unit for monitoring a potential of the power supply line of the communication interface, wherein the potential of the power supply line falls below a specified value. A peripheral device comprising: a power-saving execution unit configured to perform power-saving of the peripheral device when the power consumption of the peripheral device is reduced. 2. The peripheral device according to claim 1, wherein the communication interface is USB or IEEE1394. 3. A peripheral device connected to a host device via a communication interface capable of indicating the presence / absence of bus activity of the host device, detecting whether or not the communication interface indicates absence of bus activity. A peripheral device comprising: a detection unit that performs power saving; and a power saving execution unit that performs power saving of the peripheral device when it is detected that the bus activity is not present. 4. The peripheral device according to claim 3, wherein the communication interface is a USB, and the detecting unit detects the presence or absence of a bus activity based on whether the USB chip is in a sleep mode. 5. A peripheral device connected to a host device via a communication interface in which a data receiving side returns an acknowledgment signal to a data transmitting side, wherein data for transmitting data to the host device is provided. A peripheral device comprising: a transmitting unit; and a power saving execution unit that executes power saving of the peripheral device when no acknowledgment signal is returned from the host device in response to the data transmission. 6. The peripheral device according to claim 1, further comprising request receiving means for receiving a power saving execution request from a user, wherein the power saving executing unit executes the power saving when recognizing the power saving execution request. . 7. The peripheral device according to claim 1, which is a printer. 8. A power saving method for a peripheral device connected to a host device through a communication interface having a power supply line, wherein a step of monitoring a potential of the power supply line of the communication interface; Performing a power saving of the peripheral device in the following case: 9. A power saving method for a peripheral device connected to a host device via a communication interface capable of indicating the presence / absence of bus activity of the host device, wherein the communication interface indicates that there is no bus activity. A power saving method for the peripheral device, comprising: detecting whether the bus activity has not occurred; and performing power saving of the peripheral device when the absence of the bus activity is detected. 10. A power saving method for a peripheral device connected to a host device via a communication interface in which a data receiving side returns an acknowledgment signal to a data sending side. A power saving method for a peripheral device, comprising: transmitting the data; and, if no acknowledgment signal is returned from the host device in response to the data transmission, performing power saving of the peripheral device.