Abstract:
A data processing device which can communicate with a computer terminal, comprises: a receiver to receive data transmitted from the computer terminal; a shifter to shift a state of the data processing device to a power saving state, after elapse of a predetermined time; and a releaser to release the power saving state according to specific data transmitted from the computer terminal, wherein, after the power saving state was released by the releaser, when the received data is first kind of data, the shifter shifts the data processing device to the power saving state after elapse of a first predetermined time, and, when the data received by the receiver is second kind of data different from the first kind of data, the shifter shifts the data processing device to the power saving state after elapse of a second predetermined time different from the first predetermined time.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a data processing device and a power saving control method. 
   2. Related Background Art 
   Some kinds of conventional data processing devices respectively have two modes, that is, a normal mode and a power saving mode. Here, a print device which is representative of the conventional data processing device starts an operation in the normal mode when the power source thereof is turned on. Further, at the same time, the print device comes into an idle state which is equivalent to a print waiting state. Then, if the state that a print command by a computer terminal connected through an LAN or the like is not received continues for a predetermined time, the print device comes into the power saving mode for controlling power consumption (e.g., Japanese Patent Application Laid-Open No. H08-142458). Moreover, there is a print device which can externally set and change the time by which the device comes into the power saving mode (e.g., Japanese Patent Application Laid-Open No. 2003-246117). 
   Incidentally, as a kind of power saving mode, a deep sleep mode in which a specific information packet such as Magic Packet™ used for Wake On LAN in recent years is used is known. 
   In the deep sleep mode, even if the main power source of the data processing device is off, electricity (power) is being fed at all hours to the built-in LAN controller. For this reason, the LAN controller judges whether or not the data sequence corresponding to the inherent physical address set to the data processing device is incorporated in the specific information packet received through the LAN, and, when it is judged that the data sequence is incorporated in the received specific information packet, turns on the main power source. Thus, any electricity (power) is not fed to the circuits other than the LAN controller while the power saving mode is being set, whereby it is possible to more effectively control the power consumption. 
   In addition, there is a print device which judges whether or not to release a power saving mode based on the kind of received input data (e.g., Japanese Patent Application Laid-Open No. H08-142458). In the relevant print device, the power saving mode is not released in a case where the input data represents a status response command. 
   In the deep sleep mode, feed of electricity (power) to the data processing device is made lower as much as possible, whereby the effect of power saving is high. 
   Meanwhile, in case of enabling a computer terminal newly connected on the LAN to use the data processing device connected on the LAN due to installation of the device driver corresponding to the relevant data processing device, it is first necessary to enable the computer terminal to acknowledge all the data processing devices connected on the LAN so as to confirm what kinds of data processing devices being connected on the LAN. To achieve this, the specific information packet for releasing the deep sleep mode is often transmitted unconditionally to all the data processing devices. 
   Moreover, to acquire the current status information of the data processing device, the computer terminal often transmits the specific information packet for releasing the deep sleep mode to the relevant data processing device. 
   For these reasons, there is an occasion when the deep sleep mode of the data processing device is released even though any printing is not executed. Moreover, to cause the data processing device of which the deep sleep mode has been once released to come into the deep sleep mode again, it is necessary to wait for the elapse of a predetermined time previously set to each data processing device. Therefore, electric power is needlessly consumed as compared with the deep sleep mode. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a data processing device and a power saving control method which can reduce consumption power even in a case where a power saving state is released. 
   To attain the above object, the present invention is characterized by providing a data processing device which can communicate with a computer terminal, comprising: 
   a reception unit adapted to receive data transmitted from the computer terminal; 
   a shift unit adapted to shift a state of the data processing device to a power saving state after elapse of a predetermined time; and 
   a release unit adapted to release the power saving state according to specific data transmitted from the computer terminal, 
   wherein, after the power saving state was released by the release unit,
         in a case where the data received by the reception unit is first kind of data, the shift unit shifts the state of the data processing device to the power saving state after elapse of a first predetermined time, and   in a case where the data received by the reception unit is second kind of data different from the first kind of data, the shift unit shifts the state of the data processing device to the power saving state after elapse of a second predetermined time different from the first predetermined time.       

   Moreover, to attain the above object, the present invention is also characterized by providing a power saving control method for a data processing device which can communicate with a computer terminal, the method comprising: 
   a reception step of receiving data transmitted from the computer terminal; 
   a shift step of shifting a state of the data processing device to a power saving state after elapse of a predetermined time; and 
   a release step of releasing the power saving state according to specific data transmitted from the computer terminal, 
   wherein, in the shift step, after the power saving state was released in the release step,
         in a case where the data received in the reception step is first kind of data, it shifts the state of the data processing device to the power saving state after elapse of a first predetermined time, and   in a case where the data received in the reception step is second kind of data different from the first kind of data, it shifts the state of the data processing device to the power saving state after elapse of a second predetermined time different from the first predetermined time.       

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram schematically showing structure of a print system having a data processing device according to the embodiment of the present invention; 
       FIG. 2  is a view schematically showing structure of an image forming device shown in  FIG. 1 ; 
       FIG. 3  is a block diagram schematically showing structure of a controller unit shown in  FIG. 2 ; 
       FIG. 4  is a flowchart showing a power mode switching process executed by the image forming device shown in  FIG. 1 ; and 
       FIG. 5  is a block diagram schematically showing structure of a modified example of the controller unit shown in  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, the embodiments of the present invention will be described in detail with reference to the attached drawings. 
     FIG. 1  is a block diagram schematically showing structure of a print system having a data processing device according to the embodiment of the present invention. 
   In  FIG. 1 , a print system  100  includes image forming devices  220  and  230  having image output functions and personal computers (PC)  212  and  213 , which are respectively connected with each other through a LAN. 
   Since the image forming devices  220  and  230  (data processing devices) have the same structure each other and also the PCs  212  and  213  have the same structure each other, hereinafter, the embodiments will be explained paying attention to the image forming device  220  and the PC  212 . 
   The image forming device  220  has an operation unit  140  used for performing various operations by a user, a scanner unit  10  for reading image information in accordance with an instruction from the operation unit  140 , a printer unit  20  for printing image data as an image on a sheet and a controller unit  30  for controlling the image outputs for the scanner unit  10  and the printer unit  20  in accordance with instructions from the operation unit  140  and the PC  212 . 
   The PC  212  transmits print data being the image information to the image forming device  220  through the LAN (transmission means). 
   The image forming device  220  receives the print data from the PC  212  through the LAN and executes a print-output. 
     FIG. 2  is a view schematically showing structure of the image forming device  220  shown in  FIG. 1 . 
   The image forming device  220  in  FIG. 2  is composed of the scanner unit  10 , the printer unit  20 , the controller unit  30 , a power source device  40  for generating a DC power source from an AC power source and the operation unit  140  being a man-machine interface. 
   The scanner unit  10  has an original mounting plate glass  101  for mounting originals, an automatic original feeder  146  for successively feeding originals to a predetermined position on the original mounting plate glass  101 , an original illuminating lamp  102  structured by, for example, a halogen lamp for exposure scanning the original mounted on the original mounting plate glass  101  in the main-scanning direction and a scanning mirror  103  for reflecting a reflection light reflected form the original by the original illuminating lamp  102 , and further has a scanning unit  147  for performing the scan in the sub-scanning direction under the original mounting plate glass  101 , scanning mirrors  104  and  105  for reflecting a reflection light from the scanning mirror  103  toward a CCD unit  106  to be described later, a scanning unit  148  for performing the scan in the sub-scanning direction with a half speed of the scanning unit  147  and the CCD unit  106  which includes an imaging lens  107  for forming an image upon receiving a reflection light from the scanning mirror  105 , an image pickup element  108  composed of a CCD for converting data of a formed image into, for example, an eight-bit digital image signal and a CCD driver  109  for driving the image pickup element  108 . 
   The controller unit  30  generates image data on the basis of an image signal which was output from the image pickup element  108  and controls the whole device after an instruction from the operation unit  140  was input. The details of the controller unit  30  will be described later with reference to  FIG. 3 . 
   The printer unit  20  includes a photosensitive drum  110 , an exposure unit  117  composed of, for example, a semiconductor laser or the like for forming an electrostatic latent image by exposing the photosensitive drum  110  on the basis of the image data generated by the controller unit  30 , a developing unit  118  for containing toner being a black developing agent and developing the electrostatic latent image on the photosensitive drum  110  by the toner and a pre-transfer charger  119  for applying a high voltage to the developed toner image on the photosensitive drum  110  before the image transfer. 
   The printer unit  20  also includes a manual sheet feed unit  120 , sheet feed units  122 ,  124 ,  144  and  146  for storing sheets, sheet feed rollers  121 ,  123 ,  125 ,  143  and  145  for respectively feeding the sheets on the manual sheet feed unit  120  and the sheets stored in the sheet feed units  122 ,  124 ,  144  and  146  and a registration roller  126  for feeding the sheets fed from the sheet feed rollers  121 ,  123 ,  125 ,  143  and  145  to the photosensitive drum  110 . The sheet feed rollers  121 ,  123 ,  125 ,  143  and  145  once stop the sheets on the manual sheet feed unit  120  and the sheets stored in the sheet feed units  122 ,  124 ,  144  and  146  at a position of the registration roller  126  and then start to feed the sheets so as to take a write-out timing with the developed toner image on the photosensitive drum  110 . 
   The printer unit  20  further includes a transfer charger  127  for transferring the developed toner image on the photosensitive drum  110  to the sheet to be fed, a separation charger  128  for separating the sheet, to which the toner image was transferred from the photosensitive drum  110 , from the photosensitive drum  110 , a convey belt  129  for conveying the separated sheet to a fixing unit  130  to be described later, a cleaner  11  for retrieving the residual toner remained on the photosensitive drum  110  without being transferred, a pre-exposure lamp  112  for discharging electricity from the photosensitive drum and a primary charger  113  for uniformly charging the photosensitive drum with electricity. 
   The printer unit  20  further includes the fixing unit  130  for fixing the toner image onto the sheet to which the toner image was transferred, a sorter  132  for accepting the sheet, on which the toner image was fixed, through a flapper  131 , an intermediate tray  137  for accepting the sheet, on which the toner image was fixed, through the flapper  131  and sheet feed rollers  133  to  136  and a sheet re-feed roller  138  for feeding the sheet in the intermediate tray  137  to the photosensitive drum  110  again. The flapper  131  is structured so that the feeding destination of the sheet, on which the toner image was fixed, can be switched between the sorter  132  and the intermediate tray  137 . The sheet feed rollers  133  to  136  are structured so that the sheet, on which the toner image was fixed, can not be reversed (multiple copies of one side) or can be reversed (a copy of both sides). 
     FIG. 3  is a block diagram schematically showing structure of the controller unit  30  shown in  FIG. 2 . 
   In  FIG. 3 , the controller unit  30 , which is connected to the scanner unit  10 , the printer unit  20 , a LAN and a public network, is a controller for performing the input/output of image data and device information. 
   The controller unit  30  includes a raster image processor (RIP)  360  for developing the PDL code into a bitmap image, a scanner image processing unit  380  for performing correction, processing and editing for input image data, a printer image processing unit  390  for performing correction of a printer, resolution conversion and the like for print-output image data, an image rotation unit  330  for rotating the image data, an image compression unit  340  for performing compression/expansion processes of the JPEG (Joint Photographic image Expert Group) for multi-level image data and compression/expansion processes of the JBIG (Joint Bi-level Image expert Group), the MMR (Modified Modified READ) and the MH (Modified Huffman) for binary image data, a device I/F  320  for performing conversion between a synchronous system and a non-synchronous system of the image data with a state that the controller unit  30  is connected to the scanner unit  10  and the printer unit  20  respectively being an image input device and an image output device and an image bus  308 , which is constituted under the architecture of PCI (Peripheral Component Interconnect) bus or the standard of IEEE (Institute of Electrical and Electronic Engineers)  1394 , for transmitting the image data with a high speed by mutually connecting the above sections. 
   The controller unit  30  also includes a CPU  301  being a controller of controlling the whole system, a RAM  302  being a system work memory used for operating the CPU  301  and also being an image memory used for temporarily storing the image data, an operation unit I/F  307 , which is an interface unit of interfacing with the operation unit  140 , outputs image data to be displayed on the operation unit  140  to the operation unit  140  and informs information which was input from the operation unit  140  by a user of the present system to the CPU  301 , a network unit  310 , which is connected to the LAN, performs the input/output of information, a MODEM unit  350 , which is connected to a public network, performs the input/output of the information, a ROM  303  being a boot ROM of storing a boot program of the system, a hard disk drive (HDD)  304  of storing system software, image data, software counter values and the like, a scanner/printer communication I/F  306  for communicating with CPUs in the scanner unit  10  and the printer unit  20  respectively and a system bus  3070  for mutually connecting the above sections. 
   The controller unit  30  further includes an image bus I/F  305  being a bus bridge of converting the data structure by connecting with the system bus  3070  and the image bus  308  and a power source ON/OFF unit  41  which feeds the DC power source accepted from the power source device  40  through a power line  42  to a predetermined circuit element of the controller unit  30  through power feeding lines  43  and  44  on the basis of a control signal received from the network unit  310  through a control signal line  45  and a control signal received from the CPU  301  through a control signal line  46 . The power source ON/OFF unit  41  selectively switches ON or OFF the power feeding lines  43  and  44 . The power feeding line  43  is connected with the CPU  301 , the ROM  303 , the HDD  304 , the image bus I/F  305 , the scanner/printer communication I/F  306 , the device I/F  320 , the image rotation unit  330 , the image compression unit  340 , the RIP  360 , the scanner image processing unit  380  and the printer image processing unit  390 . The power feeding line  44  is connected to the RAM  302 , the operation unit I/F  307 , the network unit  310  and the MODEM unit  350 . 
   In  FIG. 3 , when a main SW (not shown) being an original power source switch of the image forming device  220  is turned ON, the power source device  40  feeds the power to the controller unit  30 , and the power source ON/OFF unit  41  feeds the power to the power feeding lines  43  and  44 , then the controller unit  30  starts a startup sequence in accordance with the boot program stored into the ROM  303 . 
   A system program to be executed by the image forming device  220  is stored into the HDD  304 , and the system program is read from the HDD  304  on the basis of the above startup sequence to be downloaded to the RAM  302 . A series of operations of the image processing device are performed by executing the system program, which was downloaded to the RAM  302 , by the CPU  301 . 
   The image forming device  220  shown in  FIG. 1  prints out the image data transmitted from the PC  212  connected to the LAN as follows. 
   The CPU  301  stores print data being the image data received from the PC  212  connected to the LAN through the network unit  310  into the RAM  302 , and this image data is supplied to the RIP  360  through the image bus I/F  305 . The RIP  360  develops the PDL code of the image data into the bitmap image, and the image compression unit  340  properly executes a compression process to accumulate the compressed data in the HDD  304 . 
   Then, the image data accumulated in the HDD  304  is supplied to the image compression unit  340  through the image bus I/F  305 , the image compression unit  340  expands the supplied image data, the printer image processing unit  390  performs the correction of the printer, the conversion of resolution and the like, and the image rotation unit  330  properly executes an image data rotation process. 
   Subsequently, the image data, to which various processes were executed, is sent out as the print data to the printer unit  20  through the device I/F  320  to be print output by the printer unit  20 . 
   The image forming device  220  in  FIG. 1  has the function of a deep sleep mode being one of a power saving mode described in the following. 
   In the deep sleep mode, the power source device  40  feeds the power to the power source ON/OFF unit  41  through the power line  42 , and the CPU  301  controls the power source ON/OFF unit  41  so that the power feeding line  43  becomes an OFF state and the power feeding line  44  becomes an ON state. At this time, since the power is not fed to a main circuit element including the CPU  301  of the controller unit  30 , the power to be consumed by the image forming device  220  can be drastically suppressed. Further, when the network unit  310  receives a signal, since the network unit  310  can control the power source ON/OFF unit  41  so as to return to a normal mode, the image forming device  220  can perform an information communication of using the network unit  310 . 
   Also, in the deep sleep mode, since the power is fed to the RAM  302 , the RAM  302  backs up the system program by performing a self-refresh operation. 
   In the above explanation, the switching to the normal mode is performed by the network unit  310 . However, the switching to the normal mode may be performed by the MODEM unit  350  or the operation unit I/F  307  without limiting to the network unit  310 . In the former case, a facsimile communication of using the public network becomes possible. In the latter case, the reception of an instruction sent from a user who uses the operation unit I/F  307  becomes possible. 
   The image forming device  220  in  FIG. 1  performs a return to the normal mode from the deep sleep mode as described in the following. 
   When the network unit  310  receives a print command from, for example, the PC  212 , it is analyzed whether or not a data sequence corresponding to an inherent physical address set in the own unit is installed in a specific information packet included in the received print command, and when the corresponded data sequence is found, the power source ON/OFF unit  41  is controlled so as to turn ON the power feeding line  43  through the control signal line  45  and then the CPU  301  is started up. At this time, the CPU  301  judges whether or not a factor of starting up the CPU  301  depends on the return to the normal mode from the deep sleep mode in accordance with a state of the power source ON/OFF unit  41 . When it is judged that the factor of starting up the CPU  301  depends on the return to the normal mode from the deep sleep mode, the startup sequence is started. At this time, a sequence of downloading the system program to the RAM  302  from the HDD  304  is omitted, and the system program backed up by the RAM  302  when shifting to the deep sleep mode is utilized. Accordingly, the control unit  30 , which comes into the normal mode, responds to the print command from the PC and causes the printer unit  20  to start the print-output. 
   When the print-output is terminated, the CPU  301  starts to count the time and instructs the power source ON/OFF unit  41  to switch to the deep sleep mode when a previously set time has been elapsed under a state that there is not an input from the outside. The power source ON/OFF unit  41  turns OFF the power feeding line  43 , then the control unit  30  is switched to the deep sleep mode of the low power consumption. 
   At this time, the CPU  301  notifies a fact of switching to the deep sleep mode to the PC  212 . This notification is executed because the CPU  301  can not respond to an information packet form the PC  212  and can not notify a state in the deep sleep mode to the PC  212  since the electric current does not flow in the CPU  301  in the deep sleep mode, and because a specific information packet can not be transmitted if the print device is not previously recognized in order to be shifted to the normal mode by transmitting the specific information packet such as, for example, a magic packet or the like to the print device in the deep sleep mode by the PC  212 . 
   When the PC  212  searches plural print devices connected to the LAN, an information packet such as a broadcast (ARP: Address Resolution Protocol) or the like, to which the print device in the normal mode can respond, is transmitted to the respective print devices. However, as against the above situation, the print device in the deep sleep mode can not respond to the information packet. This fact is utilized in an overall search, wherein the specific information packet is prepared for the purpose of searching all the print devices in the deep sleep mode, and the interpretation is performed in the network unit  310 , and then all the print devices in the deep sleep mode are shifted to the normal mode. 
     FIG. 4  is a flowchart showing a power mode switching process executed by the image forming device  220  shown in  FIG. 1   
   In  FIG. 4 , when the image forming device  220  receives the information packet from the PC  212  (YES in a step S 401 ) (reception means), it is discriminated whether or not the image forming device  220  is in the deep sleep mode (step S 402 ), and when the image forming device  220  is in the deep sleep mode, the network unit  310  discriminates whether or not the received information packet includes an inherent pattern previously registered in the network unit  310  (step S 403 ). When the inherent pattern is not included, the present process is immediately terminated, and when the inherent pattern is included, the network unit  310  controls the image forming device  220  to return to the normal mode from the deep sleep mode (step S 404 ) (release means). The CPU  301  receives the succeeding information packet and analyzes the received information packet (step S 405 ) then executes a process in accordance with the information packet (step S 406 ). 
   In a subsequent step S 407 , the CPU  301  discriminates whether or not a print request is included in the received information packet (discrimination means), and when the print request is included, the CPU  301  discriminates whether a first set time which was previously set has been elapsed after terminating a print process under the state without an external request. If the first set time has been elapsed (YES in a step S 408 ), the CPU  301  controls the image forming device  220  to return to the deep sleep mode again (step S 409 ) (shift means), then the present process is terminated. Before elapsing the first set time (NO in the step S 408 ), when the information packet is newly received (YES in a step S 413 ), a flow is shifted to the step S 402 . 
   As a result of the discrimination in the step S 407 , when the print request is not included, for example, when the received information packet is a search packet, the CPU  301  discriminates whether a second set time which was previously set has been elapsed under the state without an external request. If the second set time has been elapsed (YES in a step S 410 ), the CPU  301  controls the image forming device  220  to return to the deep sleep mode again (step S 409 ), then the present process is terminated. Before elapsing the second set time (NO in the step S 410 ), when the information packet is newly received (YES in a step S 414 ), the flow is shifted to the step S 402 . It should be noted that when the PC transmits print data without a print request, it is discriminated whether or not the print data is included in the information packet in the step S 407 . 
   The second set time may be 0. If the second set time is 0, the CPU  301  controls the image forming device  220  to return to the deep sleep mode without performing step S 410  and step S 414 . 
   As a result of discrimination in the step S 402 , when the image forming device  220  is not in the deep sleep mode, the CPU  301  discriminates whether or not it is necessary to respond to the received information packet (step S 411 ), and when it is necessary to respond to the received information packet, the present process is terminated after the CPU  301  executes a process in accordance with the received information packet (step S 412 ), and when it is not necessary to respond to the received information packet, the present process is immediately terminated. 
   On the other hand, when the PC  212  causes the image forming device  220  to perform the print, the information packet which includes the registered inherent pattern is transmitted to the image forming device  220 , and the print request or the print data is transmitted to the image forming device  220  after confirming that the image forming device  220  returned to the normal mode. As a method of confirming that the image forming device  220  returned to the normal mode, there is a method wherein the image forming device  220  transmits a respond packet to the information packet which includes the registered inherent pattern after returning to the normal mode and the PC  212  receives the respond packet thereby confirming that the image forming device  220  returned to the normal mode, and there is a method wherein the PC  212  obtains status information of the image forming device  220  after transmitting the information packet which includes the registered inherent pattern and it is confirmed if the status information indicates the normal mode. 
   According to a process shown in  FIG. 4 , the CPU  301  controls the image forming device  220  to return to the deep sleep mode again (step S 409 ) if the first set time which was previously set has been elapsed (YES in a step S 408 ) after terminating the print process under the state without the external request, and when the print request is not included, and if the second set time which was previously set has been elapsed (YES in a step S 410 ) under the state without the external request, the CPU  301  controls the image forming device  220  to return to the deep sleep mode again (step S 409 ). Therefore, the shift to the deep sleep mode can be controlled according to the presence/absence of the print request, thereby realizing to reduce the power to be consumed by the image forming device  220 . 
   Accordingly, the image forming device  220  can immediately return to the deep sleep mode when the print request is not included in the information packet by setting that the second set time is sufficiently shortened as compared with the first set time, thereby further improving the power saving efficiency of the image forming device  220 . 
   Accordingly, it can be prevented to repeat the deep sleep mode and the normal mode frequently when the image forming device  220  frequently receives the information packet which does not include the print request by setting that the second set time becomes longer than a predetermined time, thereby preventing the deterioration of parts due to the frequent repeat of the deep sleep mode and the normal mode. 
   It should be noted that the first set time and the second set time may be respectively determined with a fixed condition or may be set or changed by the operation unit  104 . 
   At the step S 404  of  FIG. 4 , the network unit  310  switches from the deep sleep mode to the normal mode. However, it should be noted that, at the step S 404 , the network unit  310  may switch from the deep sleep mode to a second sleep mode which is different from the deep sleep mode and the normal mode. 
   In this case, when the information packet analyzed at the step S 405  includes the print request, the CPU  301  switches from the second sleep mode to the normal mode at the step S 406  and executes the process in accordance with the information packet in the normal mode. When the analyzed information packet dose not includes the print request, the CPU  301  executes the process in accordance with the information packet in the second sleep mode. 
   Some parts of the image forming device  220  (HDD  304  etc.), exclusive of the CPU  301  and the ROM  303 , are powered off in the second sleep mode. That is, it should be noted that the second sleep mode can reduce more consumption power than the normal mode. 
     FIG. 5  is a block diagram schematically showing structure of a modified example of the controller unit  30  shown in  FIG. 3 . 
   In  FIG. 5 , a controller unit  50  includes a power source switch circuit  516 , which is connected to a power source device  513  composed of an overnight power source  514  and a non-overnight power source  515 , performs a switching operation between the overnight power source  514  and the non-overnight power source  515  and is structured by an IC chip of FET (Field Effect Transistor) which consumes a little power, a clock generator  511 , a local I/F  504  to be connected to an external device  518 , a network I/F  508  to be connected to an external device  519  through a 10/100BASE-T connector and a MACROM (Media Access Control ROM)  510 . 
   The controller unit  50  also includes a LAN controller  509 , which is composed of an overnight feeding unit  509   a  and a non-overnight feeding unit  509   b  and is connected to the network I/F  508  and the MACROM  510 , manages a control of communication performed with the external device through the network I/F  508  and issues a power activation signal-(hereinafter, called a “PME”) to be described later, an expansion I/F  506 , to which an optional device is mounted in order to expand the function, issues the PME, a hard disk drive (HDD)  512  which stores an initialization program to be read in at a time of turning ON the power of the image forming device  220  or a main program for defining an operation of the controller unit  50 , an operation display unit  505 , which displays status of the image forming device  220  including the controller unit  50  and is utilized when a user modifies parameters concerned with various image processes, issues the PME, a power saving mode setting unit  517  which holds the setting contents concerned with the discrimination whether or not it is shifted to the deep sleep mode and an SDRAM (Synchronous Dynamic RAM)  503  which temporarily stores data obtained by developing the print data received from the external device through any interface, various programs, various parameters to be written in the register when each of functions is initialized. The above sections are connected to a controller chip  502 . 
   The PME, which is an abbreviation of “Power Management Event”, is utilized for an instruction of turning ON the power of a system. The PME can be received by a system which has a bus based on the PCI2.2 standard. In the present embodiment, the PME is utilized as a signal for returning to the normal mode from the deep sleep mode. However, in the present invention, it is not limited to the PME but an independent instruction signal or another instruction signal which can instruct to turn ON the power can be applied to the present invention. 
   The controller chip  502  contains a local I/F controller  507  connected to the local I/F  504  and includes, although they are not shown, a ROM for storing various programs, an interface, a RAM (including DRAM), a PCI (Peripheral Component Interconnect) bus I/F, a video I/F, the hardware for developing data of the description language for the print transmitted from an external device and an ASIC (Application Specific Integrated Circuit) having a function of compressing and expanding various data. 
   The overnight power source  514  feeds the power to an overnight feeding group composed of the power source switch circuit  516 , the operation display unit  505 , the network I/F  508 , the expansion I/F  506 , the overnight feeding unit  509   a  of the LAN controller  509  and the MACROM  510  (these sections are denoted by surrounded broken lines in  FIG. 5 ). 
   The non-overnight power source  515  feeds the power to a non-overnight feeding group composed of the controller chip  502 , the non-overnight feeding unit  509   b  of the LAN controller  509 , the clock generator  511 , the local I/F  504 , the power saving mode setting unit  517  and the hard disk drive  512  (these sections are denoted by surrounded actual lines in  FIG. 5 ). 
   The circuit elements of the overnight feeding group are in a state that it is unable to receive the print data from the external device, execute a process thereof and respond to an obtaining request of status information. That is, the circuit elements are necessary for returning to the normal mode from the deep sleep mode and always require the power feeding even when a state without an external request continues. Therefore, the controller unit  50  controls the power source switch circuit  516  in order that only the overnight power source  514  is caused to feed the power and the non-overnight power source  515  is caused not to feed the power when it is the deep sleep mode, and when it is returned to the normal mode, the non-overnight power source  515  is also caused to feed the power. In the deep sleep mode, the power to be consumed by the circuit element which manages the local I/F controller  507  is saved. 
   When the power source switch circuit  516  receives the PME from the operation display unit  505 , the expansion I/F  506 , the LAN controller  509  or the like, the power is fed to the circuit elements denoted by the actual lines by the non-overnight power source  515 , and the image forming device  220  returns to the normal mode from the deep sleep mode. 
   The setting contents concerned with the shift to the deep sleep mode from the normal mode are held in the power saving mode setting unit  517 , and the held setting may be interpreted as the setting of determining whether or not it is shifted to the deep sleep mode from the normal mode in a case that the external device  518  is connected through the local I/F  504 . 
   In the LAN controller  509 , the overnight feeding unit  509   a , which has a function of recognizing the specific information packet through the network I/F  508 , recognizes the specific information packet such as the magic packet and issues the PME. Of course, the specific information packet is not limited to the magic packet but a specific information packet which is uniquely defined is available. In this case, the uniquely defined specific information packet may be previously set in the MACROM  510 . The non-overnight feeding unit  509   b , to which the power is simultaneously fed when the overnight feeding unit  509   a  issues the PME, manages a function of performing the data communication with the controller chip  502  when the specific information packed is not recognized. 
   Incidentally, it is needless to say that the controller unit  50  in  FIG. 5  executes a process in  FIG. 4 . 
   According to the data processing device and a power saving control method concerned with the present invention, the power to be consumed can be more decreased even if there is a case that the deep sleep mode is released. 
   The decreasing amount of the power to be consumed when the print process is not executed can be increased, even if the deep sleep mode is released in spite of a fact that the print process is not executed. 
   Since the second set time is shorter than the first set time, a time required for sifting to the power saving condition from the state of releasing the power saving condition can be shortened. Thereby, the power to be consumed can be surely decreased. 
   Since specific data is a command for releasing the sleep of the print device but is not a command for executing a print process, the power saving condition of the print device can be released other than a case that a computer terminal causes the print device to execute the print process. 
   When the specific data contains a data sequence generated based on a physical address inherent in the data processing device, since the power saving condition of the data processing device is released, the power saving condition of a desired data processing device can be surely released. 
   Since second kind of data is a search packet used for searching the data processing devices to be connected through a network after forcedly releasing the power saving condition of the plural data processing devices which were in the power saving condition, all of the plural print devices connected to the network can be surely searched. 
   This application claims priority from Japanese Patent Application No. 2004-201802 filed Jul. 8, 2004, which is hereby incorporated by reference herein.