Printing system

When a printing operation is executed according to an application program, the environment set section 70 of the printer driver is called at a predetermined timing to obtain the information on an output port (S2) and, if the output port is ready (S3: YES) and the data transmission interval between the latest data transmit time set in the data transmit time control section 73 and the present time is more than a reference time (S4, S5: YES), the wake-up command transmission section 72 is caused to transmit an automatic wake-up command to the laser printer 40 during a sleep mode.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a printing system having a computer system
 for executing various application programs and a printer with a sleep
 mode, and more particularly to a printing system enabling an automatic
 wake-up operation of a printer to make a prompt printing operation by
 transmitting a wake-up command to the printer which is in the sleep mode
 when a printer driver is called through an operating system (OS) in
 preparation for a printing operation according to an application program.
 2. Description of Related Art
 Heretofore, for one of printers which print in accordance with the print
 data transmitted from a personal computer, there has been known a printer
 which enters a sleep mode by cutting off power supply to a part of a hard
 wear of the printer itself if it does not perform a printing operation for
 more than a preset time.
 The sleep mode is an effective function for power saving in printers.
 Because it can prevent a toner fixing heater from being continuously
 heated while the printer does not perform printing for a long time, which
 would cause waste power consumption.
 The printer with the sleep mode, generally, is arranged so that it is
 released from the sleep mode when the printer receives a signal
 representative of print data from, for example, a personal computer and
 then starts a warm-up process. If, however, the print data is transmitted
 from a personal computer to the printer during a sleep mode, the printer
 could start a printing operation after the elapse of a remarkably long
 time from the signal transmit time, so that it takes a long time to
 complete the printing operation.
 To resolve the above problem, for instance, in Japanese Patent unexamined
 publication No. 7-210039, there is disclosed a power saving printing
 method of a printing system having a personal computer with an input
 device and an image forming device for performing a printing operation
 when the device receives a print code from the computer, wherein a power
 saving mode is established when the device does not carry out a print
 operation for a predetermined period of time. This method includes
 inputting a dummy print code from the computer to the image forming device
 when the specific input previously provided in the input device of the
 computer enters to the image forming device during the power saving mode,
 and performing a wake-up operation of the device when received the dummy
 print code to enter a standby mode.
 According to the above power saving printing method, a wake-up operation
 can be performed by computer input prior to an actual printing operation,
 which makes it possible to reduce a time required to perform a wake-up
 operation of the device in the power saving mode in preparation for a
 printing operation.
 However, this method needs the entry of the specific input through the
 input device of the computer in order to wake up, prior to a printing
 operation, the image forming apparatus during the power saving mode. Such
 entry of the specific input has to be executed by a user entering a
 specific code with a keyboard of the computer prior to a printing
 operation, but most of users often forget to enter the specific code in
 advance.
 If a user had forgotten to enter the specific code in advance, the wake-up
 operation of the image forming device is performed at the time that a
 print code is input according to a print start command. In this case, a
 printing operation is executed after the long lapsed time from the time
 print data have been transmitted to the image forming device, resulting in
 a long printing time.
 SUMMARY OF THE INVENTION
 The present invention has been made in view of the above circumstances and
 has an object to overcome the above problems and to provide a printing
 system capable of automatically early performing a wake-up operation of a
 printer to enable a prompt printing operation by transmitting a wake-up
 command to the printer which is in the sleep mode when a printer driver is
 called in preparation for a printing operation according to an application
 program, without needing any specific operation such as the entry of a
 specific code.
 Additional objects and advantages of the invention will be set forth in
 part in the description which follows and in part will be obvious from the
 description, or may be learned by practice of the invention. The objects
 and advantages of the invention may be realized and attained by means of
 the instrumentalities and combinations particularly pointed out in the
 appended claims.
 To achieve the objects and in accordance with the purpose of the invention,
 as embodied and broadly described herein, there is provided a printing
 system comprising a computer system which executes various application
 programs and a printer which enters a sleep mode when no print data is
 transmitted thereto from the computer system for more than a predetermined
 sleep time, the system further comprising means for detecting that a
 printer driver corresponding to the printer has been called at a time of a
 printing operation performed according to an application program, and
 means for transmitting a wake-up command to the printer being in a sleep
 mode when the call detecting means detects the call to the printer driver.
 According to the printing system of the present invention, at the time that
 a printing operation is started according to an application program, the
 call detecting means detects that the printer driver corresponding to a
 printer concerned is called and the wake-up command transmission means
 outputs awake-up command to the printer during a sleep mode. Accordingly,
 the printer can automatically be woken up early prior to a printing
 operation, thus enabling a prompt printing process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 A detailed description of one preferred embodiment of a printing system
 embodying the present invention will now be given referring to the
 accompanying drawings. First, a schematic structure of the printing system
 in the embodiment will be described with reference to FIGS. 1 and 2. FIG.
 1 is a perspective view of a printing system and FIG. 2 is a block diagram
 of a computer system and a laser printer in the printing system.
 In FIG. 1, a printing system 1 has a computer system 10 and a laser printer
 40 connected to the computer system 10 through a parallel cable 80. This
 computer system 10 is provided with a computer 12 as a central unit. The
 computer system 10 has also a display 14, a keyboard 16, and a mouse 18,
 all connected to the computer 12. The laser printer 40 is provided with a
 main body 42, a paper supply tray 44, a paper discharge tray 46, and
 others. A control panel 48 is provided on the upper plane of the main body
 42.
 In the computer 12, as shown in FIG. 2, CPU 20, ROM 22, RAM 24, a hard disc
 device (HDD) 26, a display interface (display I/F) 28, a keyboard
 interface (keyboard I/F) 30, a mouse interface (mouse I/F) 32, a parallel
 interface 34, and a timer 36 are connected with one another through a bus
 line. The keyboard 16 is connected to the keyboard I/F 30. The mouse 18 is
 connected to the mouse I/F 32. An end of the parallel cable 80 is
 connected to the parallel I/F 34. The display 14 is connected to the
 display interface 28.
 The HDD 26 stores a predetermined operating system (OS) and other
 application programs which are executed individually on the operating
 system.
 Furthermore, the HDD 26 stores printer drivers corresponding to various
 types of printers, which will be loaded on RAM 24 at a predetermined
 timing under the control of the operating system. Instead of the RAM 24, a
 part of HDD 26 may be used as a virtual memory. The printer driver is
 explained below, referring to FIG. 3 which is a schematic conceptual
 diagram of the printer driver. In FIG. 3, a printer driver PD mainly
 includes an environment set section 70, a print process section 71, a
 wake-up command transmission section 72, and a data transmit time control
 section 73.
 The environment set section 70 is a part where set is the information on an
 output port of the laser printer 40 to which printing data is to be
 outputted, more specifically, the information related to the output port,
 for example, a local printer port, a network port, and the like,
 designated by an user through the operating system. When this environment
 set section 70 is called through the application program under the control
 of the operating system, an automatic wake-up routine is executed as will
 be mentioned later.
 The print process section 71 is a part which is called through the
 operating system at the start time of a print process, at the end time of
 the print process, and the end of page, and others when a print start
 command is generated from the application program thereby to start the
 printing process. The print process section 71 transmits print data to the
 laser printer 40 through the parallel cable 80.
 The wake-up command transmission section 72 is a part which transmits an
 automatic wake-up data or command to the laser printer 40 through the
 parallel cable 80, according to the output port information in the
 environment set section 70. In this regard, the wake-up command
 transmission section 72 transmits the automatic wake-up command only when
 the difference between the latest transmit time stored every output port
 in the data transmit time control section 73 and the present time, namely,
 a data transmission interval is more than a predetermined time. The
 present time is counted by the timer 36.
 For the wake-up command, a reset command which resets the laser printer 40
 is preferably used. With this reset command, even if there remain the
 print data that have not been printed out yet before the laser printer 40
 enters a sleep mode, the reset command can the remaining print data to be
 printed out. The laser printer 40 reset according to the reset command can
 be initialized at the same time in preparation for the next printing
 operation, thereby preventing malfunction.
 The data transmit time control section 73 is for controlling the latest
 transmit time by storing the transmit time when a automatic wake-up
 command or print data is transmitted from the print process section 71, in
 combination with the information on the output port concerned.
 Returning to FIG. 2, the laser printer 40 has CPU 50, ROM 52, RAM 54,
 sensors 56 such as a paper supply sensor and a toner sensor, a driver
 circuit 58, a parallel interface 60, a control panel 48, a printing
 mechanism 62, and others. All sections except for the printing mechanism
 60, namely, the CPU 50 to the parallel interface 60 are connected to one
 another through a bus line. The printing mechanism 62 is connected to the
 driver circuit 58.
 The printing mechanism 62 includes a well known photosensitive drum, a
 charger for charging the photosensitive drum, a laser irradiation
 mechanism for irradiating the photosensitive drum with a laser beam, a
 paper supply roller, a transfer roller, a developing roller, a cleaning
 roller, a motor for driving those rollers, and a heater for toner
 fixation. The printing mechanism 62 prints printing data on the paper
 supplied from the paper supply tray and discharge it after printing. The
 driver circuit 58 is to control the operation of each section in the
 printing mechanism 62 in accordance with the printing data temporality
 stored in the RAM 54 in accordance with an instruction from the CPU 50 to
 enable the printing mechanism 62 to execute a printing operation.
 Receiving no print data from the computer system 10 for more than a
 predetermined period, the laser printer 40 enters a sleep mode under the
 control of the CPU 50.
 Next, operation of the printing system constructed as above will be
 described with reference to FIGS. 4(A) and 4(B). FIG. 4(A) is a flowchart
 of an automatic wake-up process routine of the printing system 1, and FIG.
 4(B) is a flowchart of a print process routine. Here, it is conditioned
 that the laser printer 40 has entered the sleep mode through the CPU 50 as
 mentioned above.
 Explaining the automatic wake-up process with reference to FIG. 4(A), in
 step (referred to as S hereinafter) 1, when the application program is
 started up under the control of the operating system, a printer driver PD
 corresponding to the laser printer 40 is selected from the printer drivers
 stored in the HDD 26 and is loaded on the RAM 24. In 52, the environment
 set section 70 of the printer driver PD is called through the operating
 system. The environment set section 70 thus obtains the information on the
 output port. It is detected that the printer driver has been called.
 Many cases are conceivable for the time the operating system calls the
 environment set section 70 of the printer driver PD. For example, as
 mentioned above, there is a case that the environment set section 70 is
 called at the start-up time of the application program.
 In the other case, if the operating system is "Windows 95" and the like,
 the environment set section 70 is called when the print setting mode of
 the laser printer 40 is established on the application program, more
 specifically, when a dialog box for the print setting mode is displayed on
 a display 14. In the other case, similarly, when the printer driver PD is
 switched to a different one on a dialog box for the print setting mode
 displayed on a display 14, the environment set section 70 of the printer
 driver PD is called.
 The above timing to call the environment set section 70 of the printer
 driver PD may be selected according to conditions of the printing system.
 Subsequently, in S3, it is determined whether the designated output port
 corresponding to the output port information obtained in S2 is in a ready
 state. If it is not ready (S3: NO), the process is finished, while if it
 is ready (S3: YES), the process proceeds to S4. In this way, the
 designated port of the laser printer 40 is checked to be ready or not when
 the printer driver PD is called and, if it is not ready, the printer
 driver PD does not transmit an automatic wake-up command to the laser
 printer 40.
 In S4, the data transmit time control section 73 is referred to obtain the
 latest transmit time stored in corresponding to the designated output
 port. In S5, thereafter, the difference between the present time (counted
 by the timer 36 and so on) and the latest transmit time obtained in S4, in
 other words, the data transmission interval, is calculated. It is
 determined whether the thus obtained data transmission interval is larger
 than a predetermined reference time. This reference time is preferably set
 to the same value as a sleep time that is the period from the completion
 of printing to the start of a sleep mode. For instance, the reference time
 is set to 1 min. for the sleep time of 1 min. The judgement is made
 because continuous transmission of the automatic wake-up command before a
 reference time passes from the latest transmission of the automatic
 wake-up command or the print data will cause the laser printer 40 that is
 not in the sleep mode to wake up, heating a heater in a fixing section of
 the laser printer 40, resulting in unnecessary consumption of energy. This
 is against power saving. The judgement is also done in order to avoid
 unnecessary data transmission process which may apply extra loads on the
 computer system.
 When the data transmission interval is smaller than the reference time (S5:
 NO), the process is finished. When it is larger (S5: YES), on the other
 hand, the process advances to S6 where the wake-up command transmission
 section 72 corresponding to the designated port transmits an automatic
 wake-up command to the laser printer 40. The laser printer 40 is thus
 released from the sleep mode and performs a warm-up operation in each
 section of the printing mechanism 62 in preparation for a printing process
 which is to be executed thereafter.
 In S7, the data transmit time control section 73 is called to set the
 transmit time corresponding to the designated output port. Thus, the
 process is finished.
 Next, referring to FIG. 4(B), the printing process is explained. The
 printing process is started in accordance with a print start command
 generated from the application program (S8). In S9, the print process
 section 71 of the printer driver PD is called through the operating
 system. In response to the call, the print process section 71 transmits
 print data to the laser printer 40 through the parallel cable 80, causing
 the printing mechanism 62 and others to perform a print process
 After completion of the print process, in S11, the data transmit time
 control section 73 is called to set the print data transmit time
 corresponding to the designated output port to which the print data was
 transmitted. Accordingly, the transmit time stored in the data transmit
 time control section 73 is updated to the latest transmit time and stored.
 According to an application program or an operating system, there is a case
 that, in response to the print start command generated in S8, the
 environment set section 70 is called before the print process section 71
 is called. In this case, after the execution of the S2 and subsequent
 processes shown in FIG. 4(A), the S9 and subsequent processes are
 performed.
 As mentioned above, in the printing system 1 in the present embodiment,
 when a printing operation is performed pursuant to t an application
 program, the environment set section 70 of the printer driver PD called at
 predetermined timing is given the information on the output port (S2). If
 the designated output port is ready (S3: YES) and the data transmission
 interval which is calculated by subtracting the present time from the
 latest data transmit time set in the data transmit time control section 73
 is larger than a reference time (S4, S5: YES), an automatic wake-up
 command is transmitted to the laser printer 40 being in a sleep mode.
 Accordingly, without needing any conventional operation such as input of a
 specific code, the printing system can cause the laser printer 40 to
 automatically wake up prior to a printing operation, thus achieving a
 prompt printing process.
 Furthermore, a determination is made as to whether the designated output
 port of the laser printer 40 is ready when the environment set section 70
 is called (S3) and, if it is not ready (S3: NO), the wake-up command
 transmission section 72 does not transmit an automatic wake-up command to
 the laser printer 40, while transmits the command (S6) only it the
 designated output port is ready (S3: YES). The transmission of an
 automatic wake-up command is caused only when the laser printer is in a
 print ready state. This makes it possible to avoid unnecessary processes
 and increase the speed of a printing process.
 The printing system is also arranged so that the data transmission section
 72 transmits an automatic wake-up command to the laser printer 40 (S6)
 only when the data transmission interval obtained from the latest transmit
 time of an automatic wake-up command or print data, set in the data
 transmit time control section 73, is larger than a reference time (S5:
 YES). This can avoid unnecessary wake-up operation of the laser printer 40
 to prevent waste power consumption thereof. It is also possible for both
 the computer system and the printer to prevent unnecessary data
 transmitting and receiving processes which deteriorates through-put
 (processing speed).
 The present invention may be embodied in other specific forms without
 departing from the spirit or essential characteristics thereof. For
 instance, in the above embodiment, through an application program under
 the control of an operating system, the printer driver PD corresponding to
 the laser printer 40 is selected from the printer drivers stored in the
 HDD 26 and loaded on RAM 24 (SI) and then the environment set section 70
 of the printer driver PD is called through the operating system. In the
 case that the printer driver PD has already been loaded on RAM 24,
 however, the environment set section 70 is directly called, instead of
 loading of the same printer driver PD on the RAM 24 again.
 Although the above embodiment describes the automatic wake-up operation of
 a heater in a fixing section and the like of the laser printer 40 having a
 sleep mode, the present invention can also be applied to the wake-up
 operation of laser scanners and the like which can enter a sleep mode.
 The present invention can be applied to, for instance, scanner devices
 (optical read-out devices) having a sleep mode. In this case, the same
 effect can be obtained if a device driver (scanner driver) conformable to
 the scanner device has a similar function to the printer driver mentioned
 above. It can also be applied to other device drivers.
 Furthermore, in the above embodiment, the computer system 12 has originally
 stored in HDD 26 various application programs, printer driver, and other
 programs; however, those programs stored in memory medium such as a
 CD-ROM, a floppy disc, etc. may be loaded in the computer system that
 stores therein no application programs and others.
 The foregoing description of the preferred embodiment of the invention has
 been presented for purposes of illustration and description. It is not
 intended to be exhaustive or to limit the invention to the precise form
 disclosed, and modifications and variations are possible in light of the
 above teachings or may be acquired from practice of the invention. The
 embodiment chosen and described in order to explain the principles of the
 invention and its practical application to enable one skilled in the art
 to utilize the invention in various embodiments and with various
 modifications as are suited to the particular use contemplated. It is
 intended that the scope of the invention be defined by the claims appended
 hereto, and their equivalents.