JP2004009540A - Printer and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which can reduce the consumption of electric power and a method for controlling the printer. <P>SOLUTION: The printer 1 has different kinds of host interfaces of a USB interface 11, Ethernet 12, and an IEEE 1394 interface. A CPU 4 judges, upon receiving data, from which interface the data are received, and when the data are received from a higher speed interface, a dynamic clock of a higher frequency is set by a clock control circuit 8. In this way, the CPU 4, an image processing circuit 19, an engine control circuit 21, etc., can be driven corresponding to the transfer speed of data sent from the host at a necessary and sufficient speed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printer having, for example, a plurality of host interfaces (I / F), a plurality of transfer modes of a host I / F, a plurality of compression methods for image data transferred on the host I / F, and a plurality of print modes. More particularly, the present invention relates to a power management method for a printer.
[0002]
[Prior art]
FIG. 6 shows a system configuration example of a conventional ink jet printer. In FIG. 1, a printer 1 includes a controller unit 2 and an engine unit 3. The controller unit 2 controls the entire printer so that printing can be performed based on commands and data sent from a host computer via a parallel port I / F that is a host I / F of the printer 1. The engine unit 3 controls a driving mechanical unit (not shown) that conveys printing paper of a printer, moves a head unit, and the like based on an instruction from the controller unit 2 and monitors the state of various sensors to print drawing data. And controls the ink to be ejected from the head in synchronization with the operation of the feed drive mechanical unit.
[0003]
The CPU 4 controls the entire operation of the controller unit 2 and has a ROM control circuit 5 capable of connecting a ROM, a RAM control circuit 6 capable of connecting a RAM, and a local bus control function 7 for connecting peripheral devices. The clock control circuit 8 has a plurality of clock outputs (201 to 204). Only the CPU clock 202 can variably control the output frequency by control from the CPU (control signal 200).
[0004]
The ROM 9 stores firmware and fixed data for controlling the operation of the printer 1, and is connected to a ROM control memory bus 102 configured by the ROM control function 5 of the CPU 4. The RAM 10 is a memory that stores a work area when the CPU 4 executes a program, image data transmitted from the host computer, and the like, and is connected to the RAM control memory bus 103 configured by the RAM control function 6 of the CPU 4. The RAM control memory bus 103 is connected to the RAM control memory bus 103 so that the image data on the RAM 10 can be shared and accessed by the image processing circuit 19 for converting the image data into drawing data corresponding to the required printing speed, required image quality, and the like, in addition to the CPU 4. It is also connected to an image processing circuit.
[0005]
The host I / F 24 is an interface for communicating with the host computer 14, and has conventionally been mainly constituted by a parallel port. The host I / F 24 is connected to the local bus 101 configured by the local bus control function 7 of the CPU 4, and controls data transfer between the host computer 14 and the CPU 4. The operation panel I / F 17 is also connected to the local bus 101, and controls the operation panel 18 (displaying the operation state of the printer and setting and inputting the operation mode) composed of a small LCD display and numeric keys.
[0006]
The engine I / F 20 is an interface for performing image processing by the image processing circuit 19 to convert image data sent from the host computer 14 into drawing data, and then transferring the drawing data to the engine unit 3. The transfer of drawing data from the engine I / F 20 to the drawing data memory 22 which is built in and controlled by an engine control circuit 21 (described later) is performed via an engine I / F bus 104. The engine control circuit 21 sends data to the head unit while controlling the drive mechanical unit of the engine unit 3 and controls the ink ejection of the head while synchronizing with the operation of the drive mechanical unit. The engine control circuit 21 temporarily stores the drawing data transferred from the image processing circuit 19, and reads out the stored data as drawing data in a data arrangement convenient for the head configuration, the order of ejection, and the like. It has a possible drawing data memory 22. Data is transferred from the engine control circuit 21 to the head via the head I / F bus 105. The head 23 discharges ink onto print paper in accordance with an instruction from the engine control circuit.
[0007]
In the above configuration, when the power of the printer 1 is turned on, the CPU 4 controls the entire control, the firmware of the ROM 9 is executed by the CPU 4, the power lamp of the operation panel 18 is turned on, and the initialization of the printer is performed. , And waits for a print request from the host I / F. The operation panel 18 displays a message indicating a printable state. In this state, when the host computer 14 attempts to send a print request command or print data, the parallel port I / F (host I / F) 24 informs the CPU 4 of the data transfer request by interrupt processing or the like. The CPU 4 establishes a communication line with the host computer 14. Further, communication conditions such as a communication mode, a format of image data, and a compression method are confirmed with the host computer and negotiated. After that, print mode designation information and image data are transferred in the communication mode of the determined communication conditions. The image data is transferred to the RAM 10 via the host I / F function or the CPU 4. The image data transferred to the RAM 10 is subjected to decoding and image processing corresponding to the image format and compression method of the communication conditions previously determined with the host computer 14, and further to the designated print mode. Image processing is performed to generate drawing data. Each time the drawing data is collected by a predetermined amount, the drawing data is transferred to the drawing data memory of the engine control circuit 21. Further, the operation of the drive mechanical unit controlled by the engine control circuit 21 and the head 23 The ink is transferred to the head 23 in synchronization with the ejection frequency and the like, and the ink corresponding to the drawing data is ejected from the head 23 onto a print sheet to perform a printing process.
[0008]
Conventionally, in the above-described printer, the operation clock of the CPU is reduced when a state in which there is no operation request of the printer, such as an operation of a printer operation panel or a command from a host computer, continues for a predetermined time.
[0009]
That is, during the printing operation, the basic operation clocks such as the CPU 4, the local bus 101, the ROM control memory bus 102, the RAM control memory bus 103, the image processing circuit 19, the engine I / F 20, the engine control circuit 21, and the ejection frequency of the head 23 are , Was always running at the highest speed to get the best performance of the printer working. After the printing process is completed, only the frequency of the basic operation clock of the CPU 4 is determined by the clock control signal 200 only when the state of no printer operation request such as a print request from the next host computer continues for a certain period of time or more. The control circuit 8 was operated) to lower or stop. That is, the state has shifted to the standby state.
[0010]
[Problems to be solved by the invention]
As described above, in the above-described conventional example, power can be saved only when the printer is in the standby state, and the printer always operates at full power during operation. In addition, even in the standby mode, the operation clocks of the circuits other than the CPU are driven at the maximum speed. Therefore, there is a problem that power consumption does not decrease so much even during standby. Further, when the driving rate is high, such as in a printer connected to a network, the number of standby states is reduced, and the effect of power management is reduced.
[0011]
On the other hand, a variety of new host I / Fs are often employed in recent printers, and the data transfer speeds of the respective host I / Fs are different. Further, even if one host I / F is viewed, there are a plurality of transfer modes, and the transfer speed also differs depending on the mode.
[0012]
In a printer equipped with such a plurality of host I / Fs or an I / F having a plurality of transfer modes even with one host I / F, conventionally, all circuits are always operated. And the bus was running at the fastest basic operating clock for the best performance.
[0013]
Therefore, when the print data (image data) between the host computer and the printer is transferred via the host I / F having a relatively low transfer speed, or even when the host I / F has a high transfer speed. When transferring in a low transfer mode (10 BASE-T mode of Ethernet, Low Speed mode of USB, S100 mode of IEEE 1394, etc.), only wasteful power is consumed. This is because even if the internal operation of the printer is fast, the print data cannot be output quickly unless the print data is transferred following.
[0014]
SUMMARY OF THE INVENTION The present invention has been made in view of the above conventional example, and has as its object to provide a printer that saves power consumption by changing the frequency of a synchronization signal of a processing unit and an output unit in accordance with a data transfer speed, and to provide a control method thereof. Aim.
[0015]
Further, in addition to the conventional power management, the type of data communication interface between the printer and the host computer (hereinafter referred to as a host I / F), its transfer mode, and the data transferred via the host I / F CPU operation clock, image processing circuit operation clock, and operation of various data buses suitable for print processing operation in each mode such as compression method, image processing mode, print mode distinguished by print resolution and print quality, etc. A means for selecting a clock, a driving pulse frequency of a head, and the like is provided, and for each of the modes, an operation is performed at a preset basic operation clock, a driving pulse frequency of the head, and the like, so that efficient power can be obtained even during a printing operation of the printer. An object of the present invention is to provide a printer capable of performing management and a control method thereof. To.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0017]
Interface means for connecting to an external device capable of receiving data at a plurality of different transfer rates;
Processing means for processing data received by the interface means in synchronization with a synchronization signal;
An output unit that outputs the data processed by the processing unit as an image in synchronization with a synchronization signal,
Frequency changing means for changing the frequency of the synchronization signal of each of the processing means and the output means in accordance with the transfer speed of the interface.
[0018]
More preferably, the interface means has a plurality of different types of interface units, and the transfer rate is determined according to the type of the interface unit.
[0019]
More preferably, the interface means can receive data in a plurality of different transfer modes, and the transfer rate is determined according to the transfer mode.
[0020]
More preferably, the data received by the interface unit is compressed by any of a plurality of different compression methods, and the frequency changing unit further includes the processing unit and the output unit according to the compression method. Change the frequency of each synchronization signal.
[0021]
More preferably, the data received by the interface unit includes an output mode indicating that the data is output by any one of a plurality of different output methods, and the frequency changing unit further includes the output mode according to the output mode. The frequency of the synchronization signal of each of the processing means and the output means is changed.
[0022]
More preferably, the higher the transfer rate, the higher the frequency.
[0023]
More preferably, the frequency of each of the synchronizing signals is optimized according to the data compression ratio so that each unit of the device has a minimum necessary operating speed.
[0024]
More preferably, the output mode indicates the pixel density of an image to be output, and the frequency of each of the synchronization signals is optimized so that each unit of the device has a minimum necessary operation speed according to the pixel density.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
FIG. 1 shows an example of a system configuration in which the present invention is applied to an ink jet printer. In FIG. 1, a printer 1 is a printer embodying the present invention, and includes a controller unit 2 and an engine unit 3. The controller 2 controls the entire printer so that printing can be performed based on commands and data sent from the host computers 14, 15, 16 via the host I / Fs 11, 12, 13 of the printer 1, respectively. The engine unit 3 controls a driving mechanical unit (not shown) that conveys printing paper of a printer, moves a head unit, and the like based on an instruction from the controller unit 2 and monitors the state of various sensors to print drawing data. And an engine unit 3 for controlling the ejection of ink from the head while synchronizing with the operation of the feed drive mechanical unit.
[0026]
The CPU 4 controls the entire operation of the controller unit 2, and has a ROM control circuit 5 capable of connecting a ROM, a RAM control circuit 6 capable of connecting a RAM, and a local bus control function 7 for connecting peripheral devices. . The clock control circuit 8 outputs a plurality of clocks (a local bus basic operation clock 201, a CPU basic operation clock 202, a ROM access basic operation clock 203, a RAM access basic operation clock 204, and an image) under the control of the CPU 4 (clock control signal 200). The output frequencies of the processing circuit basic operation clock 205, the engine I / F basic operation clock 206, the engine control circuit basic operation clock 207, and the head drive clock 208 can be variably controlled.
[0027]
The clock control circuit 8 can be realized by, for example, a PLL frequency synthesizer. In general, a PLL frequency synthesizer divides a signal having a frequency stable from a crystal oscillator or the like as a signal source into a reference signal, and generates a reference signal and a signal obtained by dividing the output signal of the PLL frequency synthesizer by a variable frequency divider. Is input to a phase comparator composed of a SAW convolver or the like, the output is input to a voltage controlled oscillator through a low-pass filter, and the output of the voltage controlled oscillator is used as an output signal of a PLL frequency synthesizer. . Here, since the frequency division ratio by the variable frequency divider can be changed according to the setting of the register and the like, the CPU 4 can control the output frequency. In order to supply clocks having different frequencies independently of each other, for example, a synthesizer is provided only for the type of the clock. However, even if the frequencies are different, if one is an integral multiple of the other, the former frequency may be divided as necessary.
[0028]
The ROM 9 is a ROM in which firmware for controlling the operation of the printer 1 and fixed data are stored. The ROM 9 is connected to a ROM control memory bus 102 configured by the ROM control function 5 of the CPU. The RAM 10 is a RAM that stores a work area when the CPU 4 executes a program, image data transmitted from the host computer, and the like, and is connected to the RAM control memory bus 103 configured by the RAM control function 6 of the CPU 4. The RAM control memory bus 103 is connected to the RAM control memory bus 103 so that the image data on the RAM 10 can be sharedly accessed by the image processing circuit 19 for converting the image data into drawing data according to the required printing speed, required image quality, and the like, in addition to the CPU 4. It is also connected to the image processing circuit 19.
[0029]
The host I / Fs 11, 12, and 13 are host I / Fs for communicating with the host computer A14, the host computer B15, and the host computer C16, respectively, and are interfaces conforming to USB 1.1, Ethernet, and IEEE 1394 standards, respectively. These host I / Fs are connected to a local bus 101 (for example, a PCI bus) configured by the local bus control function 7 of the CPU 4 and control data transfer between the host computer and the CPU 4. The operation panel I / F 17 is connected to a local bus, and controls an operation panel 18 (displaying an operation state of the printer and setting and inputting an operation mode) composed of a small LCD display and numeric keys. An operation panel I / F.
[0030]
The engine I / F 20 is an interface for performing image processing on image data sent from the host computers 14, 15, 16, converting the image data into drawing data, and transferring the drawing data to the engine unit 3. The transfer of drawing data from the engine I / F 20 to the drawing data memory 22 which is built in and controlled by an engine control circuit 21 (described later) is performed via an engine I / F bus 104. The engine control circuit 21 sends data to the head unit 23 while controlling the driving mechanical unit of the engine unit 3 and controls the ink ejection of the head while synchronizing with the operation of the driving mechanical unit. The engine control circuit 21 temporarily stores the drawing data transferred from the image processing circuit 19, and reads out the stored data as drawing data in a data arrangement convenient for the configuration of the head 23, the order of ejection, and the like. And a drawing data memory 22 capable of performing the following operations. Data is transferred from the engine control circuit 21 to the head 23 via the head I / F bus 105. The head 23 discharges ink onto print paper in accordance with an instruction from the engine control circuit 21. The head 23 continuously discharges ink onto printer paper, and the discharge speed is constant during printing of one image, and the speed is represented by a discharge frequency. The ejection frequency is determined by a head drive pulse clock (208 in FIG. 1) supplied to the head.
[0031]
FIG. 7 is a schematic view of the inkjet recording apparatus IJRA. The ink jet recording apparatus IJRA is an example of a printing mechanism of the engine unit 3 in FIG. In the figure, a carriage HC is engaged with a spiral groove 5004 of a lead screw 5005 by a pin (not shown), and leads via driving force transmission gears 5011 and 5009 in conjunction with forward and reverse rotation of a driving motor 5013. When the screw 5005 rotates, it reciprocates in the directions of arrows a and b. An ink jet recording head 23 is mounted on the carriage HC. The paper pressing plate 5002 presses the printing paper against the platen 5000 in the moving direction of the carriage HC. The photocouplers 5007 and 5008 are home position detecting means for confirming the presence of the lever 5006 of the carriage HC in this area and switching the rotation direction of the motor 5013 and the like. The mounting member 5019 is a member that supports a cap member 5022 that caps the front surface of the recording head 23. The suction unit 5015 suctions the inside of the cap, and performs suction recovery of the recording head through the opening 5023 in the cap. The mounting member 5019 is a member that enables the cleaning blade 5017 to move in the front-rear direction, and these are supported by the main body support plate 5018. As the blade 5017, a cleaning blade of a well-known form other than this form can be applied to the present embodiment. The lever 5021 is a lever for starting suction for suction recovery, and moves with the movement of the cam 5020 that engages with the carriage, and the driving force from the driving motor moves by a known transmission means such as clutch switching. Controlled.
[0032]
In the above configuration, when the power of the printer 1 is turned on, the CPU 4 controls the entire operation, the firmware of the ROM 9 is executed, the power lamp of the operation panel 18 is turned on, and after the initialization processing of the printer is performed, The printer waits for a print request from the host I / F. The operation panel 18 displays a message indicating a printable state. In this state, when any of the host computers attempts to send a print request command or print data, the corresponding host I / F function of the printer notifies the CPU 4 of a data transfer request by interrupt processing or the like. The CPU 4 controls the host I / F function and establishes a communication line with the host computer. Further, communication conditions such as a communication mode of the host I / F function, a format of image data, and a compression method are confirmed with the host computer and negotiated. After that, the print mode designation information and the image data are transferred in the communication mode of the determined communication condition. The image data is transferred to the RAM 10 via the host I / F function or the CPU 4 (or the host I / F function becomes a bus master and directly). The image data transferred to the RAM 10 is subjected to decoding and image processing corresponding to the image format and compression method of the communication conditions previously determined with the host computer, and is further processed according to the designated print mode. Processing is performed to generate drawing data. Each time the drawing data is collected by a certain amount, the drawing data is transferred to the drawing data memory of the engine control circuit 21. Further, the operation of the drive mechanical unit controlled by the engine control circuit 21 and the discharge of the head are controlled in accordance with the detection results of various sensors. The print data is transferred to the head unit in synchronization with the frequency or the like, and ink corresponding to the drawing data is ejected from the head 23 onto print paper to perform printing processing.
[0033]
In the present invention, the CPU 4 outputs the clocks of the clock control circuit 8 via the clock control signal 200 (local bus basic operation clock 201, CPU basic operation clock 202, ROM control memory bus basic operation clock 203, RAM control memory bus basic operation). Clock 204, image processing circuit basic operation clock 205, engine I / F bus basic operation clock 206, engine control circuit basic operation clock 207, head drive clock 208). When the F or slow transfer mode is used, the basic operation clock of each unit is switched to a frequency set in advance for each mode, thereby eliminating waste of power consumption.
[0034]
FIG. 2 is a flowchart of the operation of the printer 1 according to the present invention, and FIG. 3 is a table defining the speed of the basic operation clock under various conditions.
[0035]
The table of FIG. 3 shows, from the top, a state 301 in each mode of IEEE 1394, a state 302 in each mode of Ethernet, a state 303 in each mode of USB 1.1, and a low-speed operation state according to the type of the host I / F. 304, a basic operation clock in the standby state 305 is described.
[0036]
In FIG. 3, when JPEG-compressed image data is transmitted from the host computer to the printer in the S400 transfer mode of the IEEE 1394 host I / F, the basic operation clock of the local bus 101 is 33 MHz, The basic operation clock is 50 MHz, the basic operation clock of the ROM control memory bus 102 is 33 MHz, the basic operation clock of the RAM control memory bus 103 is 100 MHz, the basic operation clock of the image processing circuit 19 is 50 MHz, and the basic operation of the engine I / F bus 104. The clock is operated at 50 MHz, and the head driving frequency is operated at 25 KHz. In the host I / F of this printer, the S400 transfer mode of the IEEE 1394 host I / F has the highest data transfer rate, and the data compression rate of JPEG is higher than that of Packbits. That is, the condition at the top of the table in FIG. 3 means that the transfer rate of image data is the highest for the printer 1 and the printer 1 operates at the highest speed.
[0037]
On the other hand, in the second row of the table in FIG. 3, the compression method of the image data is Packbits with a low compression ratio. The data rate until the data is transferred from the host I / F to the RAM 10 via the local bus is the same because the transfer mode is the same. The local bus basic operation clock 201, the ROM control memory bus basic operation clock 203, the RAM The control memory bus basic operation clock 204 is the same as that at the top of the table in FIG.
[0038]
However, when the image data is decompressed (expanded) on the RAM 10, since the compression rate by Packbits is lower than that of JPEG, the amount of data to be processed per unit time is larger than that of JPEG at the top of the table in FIG. Is less. Therefore, the CPU basic operation clock, the image processing circuit basic operation clock, the engine I / F bus basic operation clock, and the head drive clock in the subsequent processes for processing the data may have slightly lower frequencies than the JPEG compression method. Good. As described above, FIG. 3 shows various circuits and buses in the case where various communication conditions and print processing in the printer for the communication conditions are performed at a minimum necessary processing speed when image data is transferred from the host computer. Are associated with the basic operation clock.
[0039]
Similarly, a high clock is associated with a high transfer rate and a low clock is associated with a low transfer rate for each host I / F and transfer mode. In addition, a lower clock is associated with a scheme with a lower compression ratio than with a compression scheme with a higher compression rate. For example, in the S100 mode of the IEEE1394 interface, the transfer rate is 100 Mbps, which is the same transfer rate as 100BASE-TX of Ethernet. Therefore, the basic operation clock is the same if the compression method is the same. The transfer rate of 10BASE-T of Ethernet is 10 Mbps, which is almost the same as 12 Mbps of HS mode of USB1.1 interface. Therefore, the basic operation clocks are the same if the compression method is the same.
[0040]
The lower two rows in the table of FIG. 3 show the correspondence of the basic operation clock when the printer is in a special state. First, the low-speed operation state 304 is a state in which there is no heavy processing such as print processing (that is, a print data waiting state), and the minimum necessary processing such as control of the operation panel 18 and monitoring of various sensors is performed. State. In this state, the firmware with a light load is being executed by the CPU 4 and only the operation panel I / F 17 is controlled via the local bus. Therefore, only the local bus, the CPU 4, the ROM control memory bus, and the RAM control memory bus are used. It only needs to operate at low speed. The standby state is a state in which, when the low-speed operation state continues for a predetermined time or more, it is predicted that there is no operation request for a while, and the apparatus enters the ultra-low power consumption mode. In this state, it is only necessary that each host I / F operates, so that only the local bus needs to operate at a low speed. When an operation request such as a print request is received from the host computer, the host I / F receiving the request supplies the CPU 4, the ROM 9, and the RAM 10 with a clock by interrupt processing or the like to shift to a low-speed operation state. The lower two rows in the table of FIG. 3 show the conditions described above.
[0041]
The contents of the table of FIG. 3 described above are also stored in the ROM 9 in the form of a table in which the firmware of the printer stored in the ROM 9 can refer to the contents.
[0042]
Hereinafter, the operation of the printer will be described with reference to the flowchart of FIG. When the power of the printer is turned on, the CPU 4 controls the entire control, and the execution of the firmware of the printer in the ROM 9 is started (step S1). Next, the power lamp of the operation panel 18 is turned on, and initialization of the entire printer is performed (step S2). Thereafter, the firmware refers to the table in which the contents of the table in FIG. 3 are associated, sets the basic operation clock of each unit corresponding to the low-speed operation state, and shifts to the low-speed operation state (step S3). At this time, a display indicating a printable state is displayed on the operation panel, and necessary minimum processing such as control of the operation panel and monitoring of various sensors is performed. Thereafter, the firmware refers to a timer managed by the firmware, determines whether there is no operation request for a certain period of time (step S4, No), and enters a state of waiting for a print request from each host I / F (step S4). Step S6, No).
[0043]
In this state, when the timer detects the continuation of a predetermined period of time (step S4, Yes), the basic operation clock of each unit corresponding to the standby state is set by referring to the table, and the state is shifted to the standby state ( Step S5). In this standby state, it is only necessary that each host I / F is operating, so that only the local bus is operating at a low speed, and the power consumption is considerably reduced.
[0044]
Thereafter, when one of the host computers attempts to send a print request command or print data (step S6, Yes), a data transfer request is issued to the CPU 4 from the corresponding host I / F function of the printer by interrupt processing or the like. Let them know. If the CPU 4 is in the standby state at this time, the CPU 4 sets the basic operation clock of each unit corresponding to the low-speed operation state so that the execution of the firmware can be resumed, and shifts to the low-speed operation state (step S7). The firmware whose execution has been resumed controls the host I / F function and establishes a communication line with the host computer (step S8). Further, communication conditions such as a communication mode of the host I / F function, a format of image data, and a compression method are confirmed with the host computer and negotiated (step S9). At this time, the basic operation clock of each unit corresponding to the condition corresponding to the communication condition determined with the host computer is set with reference to the table in which the contents of the table of FIG. 3 are associated (step S10).
[0045]
Thereafter, print processing is performed in the same manner as in the related art at the set processing speed of the basic operation clock of each unit (step S11). In other words, each process is performed at the minimum necessary circuit operation speed of each unit that can perform the printing process of the data without delay with respect to the transfer rate of the image data transferred from the host computer. In other words, the printing process can be performed at a speed corresponding to the transfer rate of the image data transferred from the host computer with the required minimum power consumption.
[0046]
When the printing process is completed, the process returns to step S3, and the above-described operation is continued until the printer is powered off.
[0047]
As described above, in addition to the conventional power management, the mode is set in advance for each mode such as the type of the host I / F, the transfer mode thereof, and the compression mode of the data transferred via the host I / F. Means for selecting the CPU operating clock, the image processing circuit operating clock, the operating clock of various data buses, the driving pulse frequency of the head, etc., corresponding to each mode, and the printing process in that mode is delayed. By operating at the minimum necessary basic operation clock of each unit or the driving pulse frequency of the head, efficient power management can be performed even during the printing operation of the printer.
[0048]
In the present embodiment, the seven reference clocks shown in FIG. 3 are supplied by the clock control circuit 8 described above. However, the local bus basic operation clock and the ROM basic operation clock have the same frequency, the CPU basic operation clock, the image processing circuit basic operation clock, and the engine I / F bus basic operation clock have the same frequency. The clock is half the frequency of the engine interface bus basic operation clock. Accordingly, the clock control circuit 8 supplies a total of three clocks in which the two basic clocks and the RAM basic operation clock different from any of them are added. Note that the highest frequency of the RAM basic operation clock is 100 MHz in FIG. If this is set to 66 MHz, the RAM basic operation clock has twice the frequency of the local bus basic operation clock, and only two clock signals are supplied by the clock control circuit 8. In the standby state, the local bus basic operation clock and the ROM basic operation clock have different frequencies. In this case, since the frequency of the ROM basic operation clock is 0 MHz, for example, the supply of the ROM basic operation clock from the clock control circuit 8 is interrupted, and a circuit for supplying a low-level DC signal as the ROM basic operation clock is configured. Thus, it is possible to supply a different frequency only in the standby state.
[0049]
Therefore, in the ROM 9, a constant corresponding to the frequency division ratio for causing the clock control circuit 8 to output the frequency shown in the table of FIG. 3 is stored in the ROM 9, the type of the host I / F to which the data is input, the transfer mode, and the data. The compression method may be registered as an index. As described above, although there are seven clocks to be supplied, it is not necessary to separately generate clocks of the same frequency. Therefore, the registered constants are based on the (local bus basic operation clock, ROM basic operation clock) system. And a system of a RAM basic operation clock and a system of (CPU basic operation clock, image processing circuit basic operation clock, engine I / F basic operation clock, engine control circuit basic operation clock). .
[0050]
At the time of frequency switching, the table is searched using the type of host I / F to which data is input, the transfer mode, and the data compression method as indexes, and the corresponding constant is divided by the variable frequency division corresponding to each system. The frequency of the generated clock signal can be switched by setting the frequency of the clock signal.
[0051]
(Second embodiment)
Many recent printers support multiple print qualities or speeds. For example, as shown in FIG. 4, three print modes of “fast”, “standard”, and “fine” are supported. These print modes are transferred as print mode designation information when print image data is transferred from the host computer, and the printer refers to the print mode designation information to determine the print mode. As shown in FIG. 4, the differences between these print modes are the output resolution, the number of passes of the multi-pass process, the number of gradations of the colors handled during image processing, and the like.
[0052]
Note that the multi-pass processing means that the printing paper is not conveyed by the head width every time the carriage HC shown in FIG. 7 is scanned once, but is conveyed so that a portion to be overlapped is left. This is the technology to complete the image. For example, assuming that the transport amount of one sheet is の of the head width, focusing on a certain area, an image of the area is formed by two head scans. This is referred to as having two paths. Further, if the transport amount of one sheet is ４ of the head width, an image is formed by four scans. This is referred to as having four passes. Similarly, the number of paths may be eight. The pixel density of an image formed according to the number of passes can be increased. Of course, in the case of multi-pass, pixels are recorded by interpolating between pixels that have already been recorded by the second and subsequent scans instead of sequentially completing images. Data is supplied to the head.
[0053]
Since the data amount and the printing speed are different depending on the mode, the load required for each functional unit of the printer is different in each printing mode. Note that, as described in the first embodiment, the description becomes complicated when combined with conditions such as a high or low data transfer rate of the host I / F. It is assumed that the transfer speed of the host I / F is sufficiently high with respect to the frequency. That is, it is assumed that the driving frequency of the head is always operating at the maximum, and the other functional units are operating to perform data processing and data transfer so that the processing of the head can be performed without delay. The fact that the head operates at the maximum drive frequency means that the head I / F bus 105 is also saturated to the maximum transfer speed.
[0054]
For example, in the "fast" mode, it is necessary to sequentially transfer data transferred from the host computer to the host I / F, CPU, RAM, image processing circuit, engine control circuit, and head. That is, each unit operates at the maximum speed. In contrast, in the "standard" mode, the data transferred from the host computer is doubled due to the increased resolution, and at first glance it seems that the local bus should operate at the highest speed. Actually, since the number of paths of the multipath is also increased, the load on the engine control circuit is increased, and the data transfer from the engine I / F (that is, the transfer rate of the engine I / F bus) is limited. Therefore, it is useless to operate not only the local bus but also the CPU and the image processing circuit, which are the preceding units, at the maximum speed.
[0055]
Further, the data transfer from the drawing data memory, which also contains the engine control circuit itself, increases, but the transfer from the heavier load engine I / F bus decreases, and the overall load decreases instead.
[0056]
Further, in the “clean” mode, the number of passes further increases, so that the local bus, the CPU, and the engine control circuit operate at a lower speed. However, since the number of gradations of the color of the data to be processed increases, the load of the image processing circuit suddenly increases, and it becomes necessary to operate at the maximum speed.
[0057]
FIG. 4 is a table corresponding to the basic operation clock frequency of each unit and the like, reflecting the above description. The configuration of the printer may be the same as that shown in FIG. 6 or the same as that shown in FIG. The configuration of the clock control circuit 8 is as described in the first embodiment.
[0058]
Hereinafter, the present embodiment will be described based on the operation flow of FIG. First, the system configuration is the same as in FIG. 1 described in the first embodiment. The contents of the table of FIG. 4 described above are also stored in the ROM in the form of a table in which the firmware of the printer stored in the ROM 9 can refer to the contents. Steps S101 to S106 in FIG. 5 are the same as steps S1 to S6 in FIG. 2 described in the first embodiment.
[0059]
If any host computer attempts to send a print request command or print data while waiting for a print request from the host in step S106 (step S106, Yes), an interrupt is issued from the corresponding host I / F function on the printer side. The CPU 4 notifies the CPU 4 of the data transfer request through processing or the like. If there is a print request, a basic operation clock corresponding to the “fast” mode in the table of FIG. 4 is set (step S107). This is because it is not possible to know in which print mode to print unless communication with the host computer is performed, so that the printer is prepared at the maximum speed for the time being.
[0060]
Next, the CPU 4 controls the host I / F function to establish a communication line with the host computer (step S108). Then, print image data, print mode designation information, and the like transferred from the host computer are received, and are stored in the RAM (step S109). Based on the received print mode designation information, a basic operation clock of each unit is set with reference to a table in which the contents of the table of FIG. 4 are associated (step S110).
[0061]
Thereafter, the printing process is performed in the same manner as in the related art at the set processing speed of the basic operation clock of each unit (step S111). In other words, each process is performed at the minimum necessary circuit operation speed of each unit which can be performed without delay with respect to the print process at the head drive frequency of the maximum speed of the printer. That is, the printing process at the highest speed in this mode can be performed with the minimum necessary power consumption.
[0062]
When the printing process ends, the process returns to step S103, and the above-described operation is continued until the printer is powered off.
[0063]
As described above, in response to each print mode designation from the host computer, the minimum necessary CPU operation clock, image processing circuit operation clock, various data bus operation clocks and heads for performing print processing in that mode. Means for selecting the drive pulse frequency of the printer, etc., corresponding to each printing mode designation from the host computer, and performing a printing process in the designated printing mode in accordance with the basic operation clock and head of each unit preset for each mode. By operating at the driving pulse frequency of the printer, efficient power management can be performed even during the printing operation of the printer.
[0064]
The table in FIG. 4 may be realized in the ROM 9 as a table of constants to be set in the variable frequency divider, using a clock having the same frequency and a frequency that is a fraction of its integer as one system. However, in the case of the present embodiment, the print mode is registered as an index. Focusing on the clock system, the difference between FIG. 4 and FIG. 3 is that in FIG. 3, the CPU basic operation clock and the image processing circuit basic operation clock belong to the same system, but are different from each other in FIG. It belongs to the lineage. Clocks not shown in FIG. 4 are supplied, for example, in the same system as in FIG. Therefore, the same clock (first system) as the local bus basic operation clock is used as the ROM basic operation clock, and the same system as the image processing circuit basic operation clock is used as the engine I / F basic operation clock and the engine control unit basic operation clock. A clock (second system) is supplied. As for the RAM basic operation clock, 100, 100, and 50 MHZ corresponding to the CPU basic operation clocks 50, 40, and 30 MHz in FIG. 3 are supplied according to the “fast”, “standard”, and “clean” modes. (Third system). The CPU basic operation clock is supplied as described in FIG. 4 (fourth system).
[0065]
Therefore, a constant corresponding to the frequency division ratio for causing the clock control circuit 8 to output the basic clock described above may be registered in the ROM 9 using the print mode as an index. As described above, although seven clocks are supplied, the registered constants correspond to the four systems described above.
[0066]
When the frequency is switched, the table is searched using the print mode as an index, and the corresponding constant is set in the variable frequency divider corresponding to each system, whereby the frequency of the generated clock signal is switched. .
[0067]
(Other embodiments)
Further, by combining the first embodiment and the second embodiment, any combination of the host I / Fs of the printer and all the modes of the host I / Fs and all the print modes is possible. Even when printing is performed, optimal power management can be performed under the printing operation conditions. In this case, the index for searching for the frequency is the type of host I / F to which data is input, the transfer mode, the data compression method, and the print mode.
[0068]
The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a device including one device (for example, a copier, a facsimile machine, etc.). May be applied.
[0069]
Further, an object of the present invention is to supply a storage medium (or a recording medium) recording software program codes for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or a CPU or a CPU) of the system or the apparatus. (MPU) reads and executes the program code stored in the storage medium.
[0070]
In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the program code itself and the storage medium storing the program code constitute the present invention.
[0071]
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. This also includes a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.
[0072]
Further, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function of the program is performed based on the instruction of the program code. This includes the case where the CPU provided in the expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.
[0073]
【The invention's effect】
As described above, for connection to an external device, an interface unit capable of receiving data at a plurality of different transfer rates, a processing unit that processes data received by the interface unit in synchronization with a synchronization signal, An output unit for outputting data processed by the processing unit as an image in synchronization with a synchronization signal, and a frequency for changing a frequency of a synchronization signal of each of the processing unit and the output unit according to a transfer speed of the interface By providing the changing means, it is possible to change the frequency of the synchronization signal of the processing means and the output means according to the data transfer speed, and to save power consumption.
[0074]
Further, by changing the frequency of the synchronization signal in accordance with the type of the interface unit, power consumption can be reduced to the minimum power required for the type of the interface unit.
[0075]
Further, by changing the frequency of the synchronization signal in accordance with the transfer mode, it is possible to reduce power consumption to the minimum power required for the transfer mode.
[0076]
Further, by changing the frequency of the synchronization signal in accordance with the compression method, power consumption can be reduced to the minimum power required for the compression method.
[0077]
Further, by changing the frequency of the synchronization signal in accordance with the output mode, it is possible to reduce power consumption to the minimum power required for the output mode.
[0078]
In addition, by changing the frequency of the synchronization signal to a higher value as the transfer speed increases, power consumption can be reduced to a minimum power required for the type of interface and the transfer mode.
[0079]
Further, by changing the frequency of the synchronization signal to a higher value when the compression ratio is higher, power consumption can be reduced to the minimum power required for the compression method.
[0080]
Also, by changing the frequency of the synchronization signal to a lower value when the pixel density of the output image is higher, it is possible to reduce power consumption to the minimum power required for the pixel density.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a printer system embodying the present invention.
FIG. 2 is a system operation flowchart of the first embodiment.
FIG. 3 is a table of a host I / F communication condition-basic operation clock frequency correspondence table.
FIG. 4 is a diagram of a correspondence table between a print mode and a basic operation clock frequency.
FIG. 5 is a system operation flowchart of the second embodiment.
FIG. 6 is a diagram illustrating a configuration example of a conventional printer system.
FIG. 7 is a perspective view of the ink jet printer.
[Explanation of symbols]
1 Printer
2 Controller section
3 Engine section
4 CPU
5 ROM control circuit
6 RAM control circuit
7 Local bus control function
8 Clock control circuit
9 ROM
10 RAM
11 UAB1.1 I / F
12 Ethernet I / F
13 IEEE1394 I / F
14 Host computer A
15 Host computer B
16 Host computer C
17 Operation panel I / F
18 Operation panel
19 Image processing circuit
20 Engine I / F
21 Engine control circuit
22 Drawing data memory
23 head
24 Parallel port I / F
101 Local bus
102 ROM control memory bus
103 RAM control memory bus
104 Engine I / F bus
105 Head I / F bus
200 clock control signal
201 Local bus basic operation clock
202 CPU basic operation clock
203 ROM access basic operation clock
204 RAM access basic operation clock
205 Image processing circuit basic operation clock
206 Engine I / F basic operation clock
207 Engine control circuit basic operation clock
208 Head drive clock

Claims (10)

Interface means for connecting to an external device capable of receiving data at a plurality of different transfer rates;
Processing means for processing data received by the interface means in synchronization with a synchronization signal;
An output unit that outputs the data processed by the processing unit as an image in synchronization with a synchronization signal,
A printer, comprising: frequency changing means for changing the frequency of a synchronization signal of each of the processing means and the output means in accordance with the transfer speed of the interface. 2. The printer according to claim 1, wherein the interface unit has a plurality of different types of interface units, and the transfer speed is determined according to a type of the interface unit. 3. The printer according to claim 1, wherein the interface unit can receive data in a plurality of different transfer modes, and the transfer speed is determined according to the transfer mode. The data received by the interface means is compressed by one of a plurality of different compression methods, and the frequency changing means further comprises a synchronization signal for each of the processing means and the output means according to the compression method. The printer according to any one of claims 1 to 3, wherein the frequency is changed. The data received by the interface means includes an output mode indicating that the data is output by any one of a plurality of different output methods, and the frequency changing means further includes a processing means in accordance with the output mode. The printer according to any one of claims 1 to 4, wherein a frequency of a synchronization signal of each of the output units is changed. 4. The printer according to claim 2, wherein the higher the transfer speed, the higher the frequency is changed. 5. The printer according to claim 4, wherein the frequency of each of the synchronization signals is optimized so that each unit of the apparatus has a minimum necessary operation speed according to a compression rate of the data. 6. The output mode indicates a pixel density of an output image, and optimizes a frequency of each of the synchronization signals so that each unit of the apparatus has a minimum required operation speed according to the pixel density. The printer as described in. A method for controlling a printer connected to an external device by an interface means capable of receiving data at a plurality of different transfer rates,
A processing step of processing data received by the interface means in synchronization with a synchronization signal;
An output step of outputting the data processed by the processing unit as an image in synchronization with a synchronization signal;
A frequency changing step of changing a frequency of a synchronization signal of each of the processing unit and the output unit according to a transfer speed of the interface. A program executed by a computer connected to an external device by an interface means capable of receiving data at a plurality of different transfer rates, by the computer,
A processing step of processing data received by the interface means in synchronization with a synchronization signal;
An output step of outputting the data processed by the processing unit as an image in synchronization with a synchronization signal;
A frequency changing step of changing a frequency of a synchronization signal of each of the processing unit and the output unit according to a transfer speed of the interface.

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