Method and apparatus for processing data

A method and apparatus for processing data, with the data processing side performing main control and the print control side including control for saving power. The print control side performs transition of a plurality of power saving states to obtain an optimal power saving state on the basis of transfer of data from the main control side, and the data processing side performs various control operations independently of the transition of the plurality of power saving states.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method and apparatus for processing 
data, in which a power saving state is set in inoperative states of the 
respective components in a system equipment and these components are 
sequentially controlled to achieve power saving of the overall system. 
2. Related Background Art 
In a system equipment having a data processing unit as a main controller 
and a print controller to independently control the data processing unit 
and the print controller, when power saying of a printer unit of the 
system equipment is taken into consideration, transition states such as a 
stop state and a ready state are set and controlled by the main 
controller. 
In the prior art described above, however, busy states occur at respective 
locations for the sake of operation convenience of the printer unit, and 
the main controller waits until these busy states are cleared. When data 
such as print data is to be transferred to the printer unit, it cannot be 
accepted unless the printer unit is ready, thus wasting time and power. 
In the above prior art, however, in transfer of print data from the data 
processing unit, after the data processing unit and a power saving 
controller set the printer unit in a ready state, the printer unit 
receives data but is kept in the ready state until a print instruction is 
received, thereby wasting power. 
In a conventional system having a data processing unit as a main controller 
and a print controller, power saving control of a printer unit is 
performed by a power saving controller in the data processing unit, and 
supply of power to the printer unit is performed in accordance with a 
supply instruction. The printer unit is powered off in response to a 
power-off instruction in accordance with status data representing an 
operating state or the like of the printer unit. 
In this prior art system, the main controller must always monitor the 
status data, thereby wasting time and power. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to include a power saving 
controller in a print controller in addition to one in a main controller 
so that the power saving controller in the print controller manages and 
controls transition of a power saving state, and transition can be 
achieved by detection signals from various input means such as a paper end 
sensor for detecting the presence of paper in addition to an instruction 
from the main controller, thereby performing power saving control of a 
print controller and instruction data transfer thereto without causing the 
main controller to manage the printer unit. 
It is another object of the present invention to perform a control method 
capable of performing data transfer of print data and the like even if the 
printer unit is set in a power saving state. 
It is still another object of the present invention to also include a power 
saving controller in a printer unit so that transition from a ready state 
to a power saving state can be performed by this power saving controller 
upon reception of print data from the main controller. 
It is still another object of the present invention to also include a power 
saving controller in a printer unit, so that when a printer unit power-off 
instruction is sent before the main controller is shifted to a power 
saving state, the printer unit power-off instruction is received by the 
power saving controller in the printer unit even if the printer unit is 
set in the power saving state, thereby performing power-off control of the 
printer unit in which the status conditions of the respective components 
of the printer unit are determined and if any printer unit component is 
being operated, the printer unit is powered off upon operation completion 
of such 0N component.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 is a perspective view showing a personal computer as a data 
processing apparatus according to the present invention. A personal 
computer 1 is constituted by components such as an apparatus main body 
101, a keyboard 102, an upper cover 104 having a display unit 103, and a 
printer unit 2. The upper cover 104 is pivotally mounted on the apparatus 
main body 101 through hinges 104a mounted at both ends of the rear end of 
the apparatus main body 101. When the apparatus is in use, the upper cover 
104 is pivoted and opened to a position where the display unit 103 can be 
easily observed by an operator. However, when the apparatus is not used, 
the upper cover 104 is closed and serves as a cover of the apparatus main 
body 101. A liquid crystal display element is used as a display element of 
the display unit 103 because the liquid crystal display element has a low 
profile. 
A printer unit having an ink-jet recording head is located in front of the 
display unit 103 and is housed in the apparatus main body 101. The printer 
unit 2 has an opening (not shown) which can be opened or closed by the 
operator, so that the recording head can be easily replaced with a new 
one. 
Recording paper 3 is inserted from a paper feed port 101a formed in the 
lower portion of the keyboard 102. The recording paper 3 is conveyed 
through a convey path extending through the apparatus main body 101 and is 
discharged through a discharge port (not shown) located on the rear side 
of the apparatus. The keyboard 102 is pivotally mounted through hinges 
102a mounted at both side edges of the apparatus main body 101. Even if 
recording paper having a relatively short length, such as an envelope or a 
postcard is used, the upper portion of the keyboard 102 can be opened, and 
the recording paper 3 can be inserted in the convey path. In this manner, 
since the convey path for the recording paper 3 is formed in the lower 
portion of the keyboard 102, various operations using the keyboard 102, 
the display unit 103, and a printer operation switch SW105 can be 
performed in a state wherein the recording paper is set in the convey 
path. 
[Schematic Block Diagram of Host-Printer] 
FIG. 2 is a schematic block diagram of the host computer and the printer. 
In the host computer, a central processing unit (CPU) manages the main 
control. A BIOS ROM (Basic Input Output System ROM) instructs basic 
control of the CPU. An application program is read out from a floppy disc 
(FDD) or a hard disc (HDD) through a floppy disc controller (FDC) or a 
hard disc controller (HDC), and the application program is executed. At 
this time, as a screen display method, characters and the like are 
displayed on a liquid crystal display (LCD) using an LCD controller 
(LCDC). A key input from the keyboard (KB) is entered through a keyboard 
controller (KBC). A numeric operation processor (FPU) supports arithmetic 
processing of the CPU. A real-time clock (RTC) represents a time lapse at 
the present moment. Even if the system is powered off, the RTC is backed 
up by an RTC battery. A DMA controller (DMAC) performs data transfer 
without going through the CPU so as to perform high-speed data transfer 
between memories, between a memory and an I/O, and between I/Os. An 
interrupt controller (IRQC) receives an interrupt from each I/O and 
performs operations in accordance with a priority order. A timer (TIMER) 
has free-running timers of several channels and performs various time 
management operations. In addition, the system shown in FIG. 2 includes a 
serial interface (SIO), an extension port (PORT), and an LED indicating an 
operating state to the user. 
In addition to the above functions of the general personal computer, a 
notebook type personal computer must operate with at least two power 
sources, i.e., an AC adapter and a battery. The notebook type personal 
computer requires power saving particularly while it is battery-operated. 
For this purpose, the notebook type personal computer comprises: a host 
power management unit (host PM unit) for performing time control for an 
on/off operation of an EL inverter, power supply to the FDD, power supply 
to the HDD, a printer-off operation, power supply to devices except for 
the RAM and VRAM, CLOCK control of the CPU and the like, and power supply 
control procedures in a suspend/resume mode; a refresh controller for 
switching to refresh the RAM and VRAM between the suspend mode and a 
CPU-CLOCK mode in accordance with an instruction signal from the host PM 
unit; and a charge controller capable of driving the host while charging 
the secondary battery. 
The printer is connected to the host computer through a general-purpose 
parallel I/F. The printer exchanges data on the I/O port register level 
and has an image equivalent to that exchanged with an external printer. 
[Circuit Diagram of Arrangement of Printer Driver] 
FIG. 4 shows arrangements of the recording or BJ head and the head driver. 
A jet unit of this embodiment has 64 orifices, the positions of which are 
respectively numbered with #1 to #64. Heater resistors R1 to R64 serve as 
jet energy generation elements arranged in correspondence with orifices #1 
to #64, respectively. The heater resistors R1 to R64 are divided into 
blocks each consisting of eight heater resistors. Switching transistors Q1 
to Q8 of a driver circuit-common are respectively connected to the blocks, 
respectively. The transistors Q1 to Q8 enable or disable energization 
paths in accordance with ON/OFF states of control signals COM1 to COM8, 
respectively. Reverse bias preventive diodes D1 to D64 are respectively 
located in the energization paths to the heater resistors R1 to R64. 
ON/OFF transistors Q9 to Q16 of a driver circuit-segment are connected to 
the heater resistors located at corresponding positions between the 
blocks. The transistors Q1 to Q16 enable or disable energization paths to 
the heater resistors in accordance with ON/OFF states of control signals 
SEG1 to SEG8. 
FIG. 5 is a timing chart of head driving timing in the above arrangement. 
At a given position in a head scanning direction, the common control 
signals COM8 to COM1 are sequentially enabled. By this enable operation, 
one block is selected and is set in an energization enable state. The 
segment control signals SEG8 to SEG1 are enabled or disabled in accordance 
with an image within the selected block, so that the heater resistors are 
selectively energized. Ink jets are formed upon heating to perform dot 
recording. 
FIG. 13 is a perspective view for explaining the internal arrangement of 
the printer unit 2 using an ink-jet recording scheme in or to which the 
present invention is embodied or applied. Referring to FIG. 13, the 
printer unit 2 comprises an ink tank 5001 and a recording head 5012 
connected to the ink tank 5001. The ink tank 5001 and the recording head 
5012 constitute a replaceable integral cartridge. The cartridge is mounted 
on a carriage 5014. The carriage is driven by a guide 5003 in a 
subscanning direction. 
A platen roller 5000 moves the recording paper 3 in the main scanning 
direction. The platen roller 5000 is rotated by a paper feed motor 5024 
for rotating the platen roller 5000. A flexible cable (not shown) for 
supplying a head drive signal pulse and a temperature control current to 
the recording head 5012 is connected between the carriage 5014 and a 
printed circuit board (not shown) having an electrical circuit for 
controlling the printer. 
The printer unit 2 having the above arrangement will be described in detail 
below. The carriage 5014 engages with a helical groove 5004 of a lead 
screw 5005 rotated through driving force transmission gears 5011 and 5009 
interlocked with forward or reverse rotation of a drive motor 5013 having 
a pin (not shown) and is reciprocated in the directions indicated by 
arrows and A paper press plate 5002 presses the paper against the platen 
5000 along the carriage movement direction. Photocouplers 5007 and 5008 
serve as home position detecting means for detecting the presence of a 
lever 5006 of the carriage 5014 within the range defined by the 
photocouplers 5007 and 5008 to change the rotational direction of the 
motor 5013. A member 5016 supports a cap member 5022 for capping the front 
surface of the recording head. A suction means 5015 draws air from the cap 
to recover the recording head 5012 through an opening 5023 in the cap 
member 5022. 
A cleaning blade 5017 is moved back and forth by a member 5019. The 
cleaning blade 5017 and the member 5019 are supported on a main body 
support plate 5018. A blade having the form described above need not be 
used, and another known cleaning blade can be applied to this embodiment. 
A lever 5021 for starting suction in suction recovery is moved together 
with movement of a cam 5020 engaged with the carriage 5014. A driving 
force from the drive motor is controlled by a known transmitting means 
such as a clutch switching mechanism. 
When the drive motor 5013 is rotated from the home position of the carriage 
5014 in the reverse direction, the power transmission gear 5011 is 
switched to a power transmission gear 5010 (although this switching is not 
illustrated), so that the driving force from the drive motor 5013 is 
transmitted to the lever 5021 through the cam 5020. Therefore, capping, 
cleaning, and suction recovery of the recording head 5012 are performed. 
[Block Diagram of Printer] 
FIG. 3 is a block diagram showing an arrangement of a control system of the 
printer unit. 
A CPU-P is a CPU in the form of a microprocessor for performing main 
control of the printer unit. The CPU-P performs desired processing on the 
basis of a printer command and data supplied from the host computer 
through a parallel IF (to be described later). A ROM-P is a ROM for 
storing programs corresponding to a recording control sequence and the 
like executed by the CPU-P, a character generator (CG), and any other 
permanent data. A RAM-P is a RAM which has a work area used as a register, 
a line buffer for storing one-line print data, a dot development buffer 
for storing the data developed into dots, and an input buffer from the 
parallel IF. A TIMER1-P is a timer for obtaining a drive phase time of a 
paper feed motor (FM), a heater, or the like. An RTC-P is an RTC for 
detecting a time lapse required for a recovery operation. A multiple 
control unit for integrally performing IF transfer control, power saving 
control, RAM access control, and printer port control is connected to the 
bus of the CPU-P. Printer drive control signals are output from the 
multiple control unit and are converted into FM, CM, BJ-Head, and heater 
drive levels by an FM driver, a CM driver, a head driver, and a heater 
driver, respectively. The energy saving signals are a Vcc1P-off, 
Vcc2P-off, and Vp-off power control signals from the multiple control 
unit, and input signals are a Printer-off signal, printer sensor signals, 
and control panel signals. Of these signals, the Vcc1-P power supply is 
performed only when the Printer-off signal is changed from an active level 
to an inactive level, and power is supplied only to the multiple control 
unit, the CPU-P, and the RAM-P. The Vcc1P-off signal can disconnect the 
Vcc1P power when the Printer-off signal is changed to OFF in accordance 
with the printer drive state. That is, the head is not powered off in a 
open cap state, and a decisive failure can be prevented. 
FIG. 6 is a block diagram showing an arrangement of the multiple control 
unit. The functional blocks of this arrangement are a parallel IF adapter 
mainly serving as a host IF adapter, an IF data take-in controller for 
storing parallel data in the input buffer (IB) of the RAM-P through the 
parallel IF adapter, a refresh controller for generating a refresh timing 
for the RAM-P, a BJ head & CM controller for reading out one-line dot 
development data (PB) in the RAM-P and controlling phase excitation of the 
carrier while a BJ head is driven to perform printing, a printer port 
controller for driving the FM driver, the heater driver, and an LED 
driver, a RAM access controller having access rights in a priority order 
for four access requests, i.e., access requests of the IF data take-in 
controller, the refresh controller, the BJ head & CM controller, and the 
CPU-P, and a printer PM controller for performing power saving control. An 
interrupt signal INT is used for a hardware interrupt shown in FIG. 22. 
The signal INT is generated on the basis of a signal from the IF data 
take-in controller, the paper insertion sensor, or the panel SW and is 
input to the CPU-P. This is the hardware interrupt shown in FIG. 22. 
FIG. 7 shows an arrangement of an I/O register (PIO/IO) in the parallel IF 
adapter when viewed from the host. This I/O register consists of an IF 
send data register, an IF receive data register, an IF status register, a 
Buffer SP register, and an IF control register. 
FIG. 8 shows an arrangement of an I/O register (PIF/IO) in the IF data 
take-in controller when viewed from the printer. The I/O register includes 
IB start, IB end, IB POINT, IB status, IB control data, and IB send data 
registers. 
FIG. 9 shows an arrangement of an I/O register (PFM/IO) in the printer port 
controller when viewed from the printer. The I/O register consists of an 
FM phase excitation, SH heater signal, and LED control registers. 
FIG. 10 shows an arrangement of an I/O register (PBJ/IO) in the BJ head & 
CM controller when viewed from the printer. The I/O register consists of 
PB start, PB end, PB POINT, PB status, PB control data, and CM phase 
excitation registers. 
FIG. 11 shows an I/O register (PFM/IO) in the printer PM controller when 
viewed from the printer. The I/O register consists of PPM status and PPM 
control data registers. 
FIG. 12 shows address area allocation in the RAM-P of FIG. 3, representing 
a print buffer (PB) for controlling the BJ head & CM controller and a 
reception buffer (IB) for controlling the IF data take-in controller. 
The print buffer area is used to set a data area required for data 
printing. A start address (PB START) and an end address (PB END) of the 
print buffer area are set to sequentially read out the storage data from 
the start address within the range of the buffer area under the control of 
the BJ head & CM controller. The storage data is read out up to the end 
address from the RAM-P and a control signal is supplied to the head 
driver. At this time, a print data address pointer (PB pointer) represents 
a data address of currently sent data. 
The reception data buffer (equivalent to an INPUT BUFFER to be described 
later) area is used to set a data area required for data reception. A 
start address (IB START) and an end address (IB END) of the reception data 
buffer are set. Storage data are sequentially read out from the start 
address within the designated range under the control of the IF data 
take-in controller. The storage data are read out from the RAM-P up to the 
end address, thereby sending a control signal to the head driver. At this 
time, a reception data address pointer (IB pointer) represents a data 
address of the currently received data. 
FIG. 14 shows a detailed arrangement of a memory map of the host RAM in 
FIG. 2. The RAM has a standard area having addresses 0000h to A0000h and 
an extended area having addresses 10000h to FE0000h. The standard area has 
a 640-KB capacity, and the extended area has a 15-MB capacity. The RAM is 
mapped to have these areas. 
A start portion of the standard RAM area which has addresses 00000h to 
000400h is allocated as an area for storing an interruption vector. This 
area stores entry addresses of the respective processing operations for 
this interrupt. 
A video RAM area and a video BIOS ROM area in FIG. 14 are allocated in the 
LCDC of FIG. 2. A video control program is stored in the video BIOS ROM 
area. Video display data is held in the video RAM area. 
An area having addresses C8000h to E0000h serves as an extended ROM area. 
This area serves as a ROM area used by an extension port and the like. 
An area having addresses F0000h to 10000h is allocated in the ROM BIOS area 
and stores a BIOS program for performing various I/O processing 
operations. 
FIG. 15 shows an address map of each I/O. Data can be exchanged between the 
respective hardware arrangements by the read and write operations with 
respect to the address ports set in the respective hardware arrangements. 
A keyboard will be taken as an example. Data is are exchanged between the 
memory and the keyboard controller through ports allocated at the 
addresses 60h to 64h. The data reception port is read-accessed to receive 
data from the keyboard. 
Similar processing operations are performed for other addresses. 
Areas represented by parallel Centronics 1 to parallel Centronics 3 
represent interface areas which are common in the I/O space to the printer 
interface area. 
FIGS. 16 and 17 show contents of the interruption vector in FIG. 14 in 
detail. An area having addresses 0h to Fh is allocated as a hardware 
interrupt area, and an area from address 10h is located to a software 
interrupt. 
A program at an address registered in each entry is executed in response to 
the corresponding interrupt. Addresses for a ROM BIOS program and a 
program stored in the RAM are set in the entries. When a hardware or 
software interrupt is generated, the corresponding processing is executed, 
and the respective operations are performed. 
Each processing after a power-ON operation will be described below. 
In the flow chart of the power-ON operation in FIG. 18, the flow advances 
to step S1. Soft reset processing by the keyboard is also executed in step 
S1 upon the power-ON operation. In step S1, POST processing is performed. 
The POST processing is power on self-test processing to test and 
initialize each hardware arrangement. The flow advances to step S2 to load 
a boot program for starting a system program. The boot program is stored 
in an FD (floppy disc) or HD (hard disc) and is located at, e.g., track 0 
and sector 0. The contents at track 0 and sector 0 are taken into a memory 
to load the boot program. Steps S1 and S2 are performed within the ROM 
BIOS. The flow advances to step S3 to execute the loaded boot program. The 
boot program is a program for loading a program for loading an OS program 
from the FD or HD. The flow advances to step S4 to load the OS load 
program. The flow advances to step S5 to execute the OS load program. The 
OS load program is a program for loading the OS in the memory. In step S6, 
an I/O driver is loaded. The I/O driver is a program for controlling an 
I/O. The OS can exchange data with each I/O by means of the I/O driver. 
The flow advances to step S7 to test and initialize the I/O. The flow 
advances to step S8 to load the OS in the memory. Up to this step, 
preparation for executing the OS is completed. The flow advances to step 
S9 to execute the OS. The OS processes inputs from the keyboard and 
displays various messages on the display unit to perform data exchange 
with the operator. The OS executes various commands in accordance with 
various command inputs by the operator. 
FIG. 19 is a flow chart for explaining the POST processing in step S1 of 
FIG. 18 in detail. The FPU (numerical operation processor) shown in FIG. 2 
is tested (step S10). The ROM is tested (step S11). The power source (P/S) 
and the battery are checked (step S12). The LCD and the LCD adapter are 
tested and initialized. The LCD adapter includes the RAM and ROM, so that 
the RAM and ROM are also checked (step S13). An interrupt controller 
(IRQC) is tested and initialized (step S14). A timer is then tested (step 
S15). The DMA controller is tested (step S16). The keyboard (KB) and the 
keyboard controller (KBC) are tested (step S17). The serial and parallel 
ports are tested and initialized (step S18). It is then checked if soft 
reset is made (step S19). If YES in step S19, the test and initialization 
of the RAM in step S20 are skipped, and the flow advances to step S21. If 
soft resetting is not detected, the flow advances to step S20, and the 
test and initialization of the RAM are performed. The FD test is then 
performed (step S21). The HD is tested (step S22). The real-time clock 
(RTC) is tested (step S23). The printer is tested. In this case, the 
printer is tested to check various printer ports and a printer connection 
(step S24). The LED is then tested (step S25). The flow then returns to 
the main routine in FIG. 18. By the above processing operations, the POST 
processing in step S1 in FIG. 18 are completed. If errors occur in 
devices, error messages are displayed. 
FIG. 20 is a flow chart of printer soft control. 
Initialization is performed in step S51. If a Printer-off signal is sent 
from the host to the printer, the flow is ended in step S56. However, if 
the Printer-off signal is not sent from the host to the printer, the flow 
advances to step S52. In power saving control in step S52, if a 
Printer-off signal is set from the host to the printer, the flow is ended 
in step S56. However, if the Printer-off signal is not set from the host 
to the printer, parallel processing in steps S53, S54, and S55 is 
executed. More specifically, step S53 executes dot data development 
processing for developing character code data in the line buffer into 
one-line dot data. Step S54 executes a series of print processing 
operations performed when the dot data of the next line is ready and a 
print start command of this line is executed or when a sequential 
execution command is executed. Step S55 executes a command take-in 
analysis for interpreting a command and data which are taken into the 
input buffer and forming a line buffer. When the processing operations in 
steps S53, S54, and S55 are completed, the flow returns to power saving 
control processing in step S52. 
FIG. 21 is a detail flow chart of initialization in FIG. 20. 
Interrupt (Int) mask processing is performed in step S61, and the flow 
advances to step S62. In step S62, devices such as the ROM-P, the RAM-P, 
and the TIMER-P are checked. The flow then advances to step S63. In step 
S63, the device I/O register for setting the above-mentioned registers 
(PIF/IO, PFM/IO, and PPM/IO) in desired set conditions is initialized. The 
flow then advances to step S65 to check if the printer is set in a cap 
position. If YES in step S65, the flow advances to step S70. However, if 
NO in step S65, printer initialization processing for performing 
mechanical positioning of the printer and subsequent recovery processing 
for capping the head after recover suction is repeatedly performed until 
an ink is discharged are performed in step S66, and the flow advances to 
step S70. It is checked in step S70 if a Printer-off signal is present in 
the printer. If YES in step S70, a series of operations in steps S71, S72, 
and S73 are performed as CPU-P procedures which serve as transition 
procedures to a Sleep Mode to be described below. The Sleep Mode is set in 
the PPM/IO register, and the CPU-P is set in the Halt Mode. However, if NO 
in step S70, the flow returns to the main flow. 
FIG. 23 is a detailed flow chart of power saving control processing in FIG. 
20. 
Interrupt mask (INT MASK) processing is performed in step S80, and the flow 
advances to step S81. It is checked in step S81 if printer drive control 
is ON. If YES in step S81, the interrupt mask is cleared in step S103, and 
the flow returns to the main flow. However, if NO in step S81, the flow 
advances to step S82 to check if one line of dot data is developed. If 
one-line dot data development is completed, the flow advances to step S83 
to check if the printer is currently set in an Active Mode. If YES in step 
S83, the flow advances to step S103. However, if NO in step S83, the flow 
advances to step S84 to turn on a printer drive power source Vp, and the 
flow advances to step S103. However, if NO in step S82, i.e., when 
one-line dot data development has not yet been completed, the flow 
advances to step S85. In step S85, the power source Vp is turned off, and 
the flow advances to step S86 to check if the dot data is developed. If 
YES in step S86, the flow advances to step S88. Otherwise, the flow 
advances to step S87 to check if a Printer-off signal is detected. If YES 
in step S87, the flow advances to step S71 in FIG. 21, and END processing 
in steps S71 and S72 is performed. However, if NO in step S87, the flow 
advances to step S103. It is checked in step S88 if data is present in the 
input buffer. If NO in step S88, the flow advances to step S87. However, 
if YES in step S88, the TIMER-P Set Mode is cleared in step S90. The 
subsequent steps S91, S92, and S93 are procedures performed expecting the 
next external hardware interrupt. After the Sleep Mode is set, the hard 
interrupt is cleared, and a Halt Mode is set. When a hard interrupt is 
detected in the state of step S93, operations correspond to steps S100, 
S101, and S102, so that the Halt Mode is cleared. The Sleep Mode is 
cleared, and Ready Mode resumption processing such as writing of a command 
corresponding to the hard interrupt is performed. The flow then advances 
to step S103. 
FIG. 22 is a chart showing transition of states of the printer PM 
controller in accordance with conditions. 
After the RESET is performed, the printer PM controller is set in a state 
A. When the Sleep Mode is set in the PMM/IO register, the printer PM 
controller is changed to a state B. The only change in state A is a change 
from state A to state B by sleep setting of the CPU-P. Changes in state B 
are two changes, i.e., a change to state A upon occurrence of paper 
insertion, an operation SW input, a data input, or the like, and a change 
to state C by the Printer-off signal from the host. 
FIG. 24 is a chart showing transition in the overall printer system. 
There are four states, i.e., a Stop Mode in which all clocks are absent and 
no power supply is made, an Active Mode in which all the power sources and 
clocks are normal and a print ready state is set, a Ready Mode without any 
printer drive power supply as compared with the Active Mode, and a Sleep 
Mode in which Vcc power supply is made to only the CPU-P, the controllers, 
and the RAM-P, the CPU-P and the RAM-P are basically inoperative, and the 
contents of the memories and registers are at least held. 
Change systems of the respective modes, CPU-P control, and the change 
systems of the controllers will be correspondingly described below. 
In the RESET state, the Ready Mode is set. This can be realized by using a 
change system of RESET.fwdarw.A in FIG. 23. 
In the Ready Mode, the first change system from the Ready Mode is a system 
of Ready Mode.fwdarw.Active Mode, which is controlled by the CPU-P in step 
S84 in FIG. 23. The second change system from the Ready Mode is a system 
of Ready Mode.fwdarw.Sleep Mode, in which when data to be processed is 
absent in an end-of-print state in a series of CPU-P operations in steps 
S81 to S93 in FIG. 23, the "Sleep" is set in the controller to obtain a 
Halt state, and the change from state A to state B (FIG. 23) occurs in the 
controller by Sleep setting. In the Active Mode, only one change system 
from the Active Mode, i.e., a system of Active Mode.fwdarw.Ready Mode, 
which is controlled by the CPU-P in step S85 in FIG. 23, is available. 
In the Sleep Mode, the first change system from the Sleep Mode is a system 
of Sleep Mode.fwdarw.Ready Mode, in which a change in state from state B 
in state A in FIG. 23 occurs by paper insertion, an operation SW input, a 
data input or the like. At the same time, a hardware interrupt is input to 
the CPU-P, and the CPU-P restores the initial state by steps S100 to S103 
in FIG. 23. The second change system from the Sleep Mode is a system of 
Sleep Mode.fwdarw.Stop Mode in accordance with a condition using the 
Printer-off signal. This second change system causes a change in state 
from state B to state C in FIG. 23 in the controller and does not require 
CPU-P control. 
When data exchange does not occur, since the Sleep Mode is set, power 
saving can be achieved. In addition, even if high-speed transfer such as 
block transfer occurs, the start of data transfer can be immediately 
restored to receive data since the Sleep Mode is set. 
The present invention exemplifies the embodiment describing an ink-jet 
recording scheme, but is not limited as to the types of printers and the 
types of recording schemes, as a matter of course. 
In addition, the present invention exemplifies an integral arrangement 
including a personal computer and a printer. However, the present 
invention is also applicable to a personal computer and a printer 
separated from the personal computer but having the same battery drive 
source as that of the personal computer. 
In addition, when a printer has a separate battery drive source, a system 
of Ready Mode.fwdarw.Stop Mode by the Printer-off signal need not be used, 
and the resultant apparatus can be realized in the form excluding this 
system. 
In state B in each of FIGS. 23, 26, and 28, a low-speed clock is supplied 
to the CPU-P. This clock speed is a minimum clock speed with which 
register data in the CPU-P can be maintained and restored. If a static 
CPU-P is used, the clock can be stopped. Similarly, the RAM-P is assumed 
as a low-cost RAM such as a D-RAM or PS-Ram which requires refresh. 
However, if a RAM which does not require refresh or has a data holding 
mode and can restore data (i.e., a static RAM) is used, power saving can 
be achieved, as a matter of course. When a voltage applied to each of the 
CPU-P and the RAM-P in the state B is switched to a voltage which can hold 
data, further power saving can be achieved. 
In addition, the present invention has been described mainly with reference 
to the personal computer as the host. However, if an arrangement in which 
a printer unit can be independently controlled is employed, the present 
invention is not limited to a specific apparatus if an apparatus (e.g., a 
Japanese wordprocessor and a system notebook) has a communicating means to 
an external device or can perform communication through a bus. 
(Second Embodiment) 
A high-speed Block Transmit Mode without being through a CPU-P is added to 
the state shown in FIG. 27. A change of Sleep Mode.fwdarw.Block Transmit 
Mode in the Block start is achieved by a change in state of B.fwdarw.D in 
FIG. 26. A change of Block Transmit Mode.fwdarw.Ready Mode corresponds to 
a change in state of D.fwdarw.A in FIG. 26. Other transition states are 
the same as those in FIG. 24, and a detailed description thereof will be 
omitted. As compared with the first embodiment, since the RAM Refresh is 
not performed, a higher-speed Block transfer can be performed. Only a 
signal line H-block is added in FIG. 25, and a detailed description of the 
signal lines will be omitted. 
(Third Embodiment) 
A high-speed Block Transmit Mode without being through a CPU-P is added in 
the state shown in FIG. 29. A change of Sleep Mode.fwdarw.Block Transmit 
Mode at the Block start is obtained by adding a change in state of 
B.fwdarw.D in FIG. 28. A change of Block Transmit Mode.fwdarw.Sleep Mode 
corresponds to a change in state of D'.fwdarw.B in FIG. 28. Other 
transition states are the same as those in FIG. 24, and a detailed 
description thereof will be omitted. As compared with the first 
embodiment, since the RAM Refresh need not be performed, higher-speed 
Block transfer can be achieved. 
As can be apparent from the above description, the power saving control 
scheme has three modes, i.e., the Active Mode for supplying at least a 
printer drive power to set the printer unit in a ready state, the Ready 
Mode for inhibiting to supply the printer drive power and allowing printer 
control except for printing, and the Sleep Mode for inhibiting to effect 
CPU control for controlling the printer unit and changing, from the Ready 
Mode, the Clock supplied to the CPU for controlling the printer unit. At 
least the changes of Active Mode.fwdarw.Ready Mode, Ready 
Mode.fwdarw.Active Mode, Ready Mode.fwdarw.Sleep Mode, and Sleep 
Mode.fwdarw.Ready Mode can be performed. At the same time, the Ready Mode 
is set in response to the RESET input. Therefore, at least the data 
exchange portion to the printer unit can perform high-speed data transfer 
without detecting the state of the printer. At the same time, since the 
printer unit is kept stopped or is powered off during a period except for 
the time required for printing, great power saving can be achieved. 
As has been described in detail above, there is provided a method and 
apparatus for processing data, wherein the data processing side for 
performing main control and the print control side for performing power 
saving control are provided, the print control side performs transition of 
a plurality of power saving states on the basis of data transfer from the 
main control side so as to obtain an optimal power saving state, and the 
data processing side performs various control operations independently of 
the transition of the power saving states. 
As has been described in detail above, there is provided a method and 
apparatus for processing data, wherein the data processing side for 
performing main control and the print control side for performing power 
saving control are provided, the print control side receives data from the 
data processing side in a ready state and determines the contents of the 
reception data, and a power saving state is set in the absence of a print 
instruction. 
As has been described in detail above, there is provided a method and 
apparatus for processing data, wherein the data processing side for 
performing main control and the print processing side for performing power 
saving control are provided, the data processing side sends a power-off 
instruction to the print processing side, the print processing side 
monitors an operating state of the printer unit and powers off the printer 
unit if the instruction from the data processing side is a power-off 
instruction.