Image processing device having a plurality of control units

An image processing device includes an operating unit and a plurality of control units each configured to control the operating unit in order to execute a function on image data. The plurality of control units include at least a first control unit and a second control unit. When a first mode is selected, the control units control the operating unit to execute the function in cooperation with each other. When a second mode is selected, at least the second control unit controls the operating unit to execute the function without cooperating with the first control unit.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2009-227645 filed Sep. 30, 2009. The entire content of this priority application is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an image processing device and a storage medium storing a control program for controlling the image processing device.

BACKGROUND

Japanese Patent-Application Publication No. H8-101609 has proposed an image processing device including a main control unit and a sub-control unit. The main control unit controls each of various units, such as a printer unit, and the sub-control unit controls an interface for communicating with external devices. During a power-saving mode, the main control unit is placed in a sleep state, and only the sub-control unit is in a running state. This configuration reduces power consumption in the power-saving mode.

SUMMARY

However, functions that can be executed when only the sub-control unit is running are so limited that the above configuration is not satisfactorily user friendly.

In view of the foregoing, it is an object of the invention to provide an image processing device capable of avoiding limiting functions executable under the control of one or more of a plurality of control units. It is also an object of the invention to provide a storage medium storing a program for controlling the image processing device.

In order to attain the above and other objects, the invention provides an image processing device including an operating unit, a plurality of control units, and a selecting unit. Each of the plurality of control units includes a processing unit and is configured to control the operating unit in order to execute a target function on image data. The plurality of control units includes at least a first control unit and a second control unit. The selecting unit selects one of a first mode and a second mode. When the first mode is selected, the plurality of control units control the operating unit to execute the target function in cooperation with each other. When the second mode is selected, at least the second control unit controls the operating unit to execute the target function without cooperating with the first control unit.

According to another aspect, the present invention provides a storage medium storing a set of program instructions executable on an image processing device and usable for controlling the image processing device. The image processing device includes an operating unit and a plurality of control units. The plurality of control units include at least a first control unit and a second control unit. Instructions include selecting one of a first mode and a second mode, controlling the plurality of control units to control the operating unit so as to execute a function on image data in cooperation with each other when the first mode is selected, and controlling at least the second control unit to control the operating unit so as to execute the function without cooperating with the first control unit when the second mode is selected.

DETAILED DESCRIPTION

Image processing systems according to embodiments of the invention will be described while referring to the accompanying drawings wherein like parts and components are designated by the same reference numerals to avoid duplicating description.

First Embodiment

As shown inFIG. 1, an image processing system1according to a first embodiment of the invention includes a terminal device10and a printer30(image processing device). The terminal device10may be a personal computer, for example.

The terminal device10includes a CPU11, a ROM12, a RAM13, a hard disk drive (HDD)14, an operation unit15, a display unit16, and a network interface (I/F)17. Although not shown in the drawings, the operation unit15includes a keyboard and a pointing device, and the display unit16includes a liquid crystal display panel. The network I/F17is connected to a communication circuit20. The HDD14stores various programs including an operation system (OS), an application software for generating image data to be printed, and a printer driver for controlling the printer30. The CPU11performs overall control of the terminal device10based on a program read from the ROM12while storing processed results in the RAM13.

The printer30is a multifunction device capable of executing a plurality of functions including a PC print function, a copy function, a scanner function, a facsimile communication function, and a facsimile print function. The printer30includes a first control unit31, a second control unit32, and a HDD34. The first control unit31includes a first CPU31A, a ROM31B, and a RAM31C. The second control unit32includes a second CPU32A, a ROM32B, and a RAM32C

Each of the ROM31B and the ROM32B stores various programs for controlling the printer30. Each of the first CPU31A and the second CPU32A performs overall control of the printer30based on a program read from the respective ROM31B,32B while storing processed results into the respective RAM31C,32C.

The first and second control units31and32have substantially the same performance level. More specifically, both the first and second control units31and32have substantially the same operating frequency (100 MHz, in this embodiment), and the RAMs31C and32C have substantially the same memory capacity.

The printer30further includes various devices (operating units) including a network I/F21, an operation unit35, a scanner unit36, a facsimile unit37, an image processing unit38, and a printing unit39.

The network I/F21is connected to the terminal device10and the like through the communication circuit20, enabling data communication therebetween. Although not shown in the drawings, the operation unit35includes various buttons through which a user inputs various commands including an execution command for each function. The operation unit35also includes a display unit (liquid crystal display panel, for example) and a lamp, and is capable of displaying various setting screens and operation status.

The scanner unit36generates scanned data by scanning an original (not shown). The facsimile unit37transmits facsimile data to or receives facsimile data from a remote facsimile device (not shown). The image processing unit38image-processes various image data. For example, the image processing unit38converts the image data into printable data. The image data may be scanned data generated by the scanner unit36, print data received at the network I/F21, or the like.

The printing unit39forms an image on a recording sheet (paper sheet, OHP sheet, or the like) based on the image data in an electrophotographic method, for example. The printing unit39includes a sheet-conveying mechanism40and a fixing unit41. The sheet-conveying mechanism40picks up recording sheets one at a time from a sheet tray (not shown) and conveys the same to a printing section (not shown), in accordance with a print start command from the first or second control unit31,32. Each of the first and second control units31and32is capable of controlling the sheet-conveying mechanism40to change a sheet conveying speed as needed. The fixing unit41thermally fixes toner images transferred onto the recording sheet. Each of the first and second control units31and32is capable of controlling the amount of heat (temperature) generated at the fixing unit41by controlling the amount of electric supply to the fixing unit41.

FIG. 2shows a device table, which is stored in the HDD34, for example. The device table shows operating frequencies (clock numbers) required to operate each of the devices (the printing unit39, the image processing unit38, the scanner unit36, the facsimile unit37, the operation unit35, and the network I/F21). As mentioned above, the operating frequencies of the first and second control units31and32are both 100 MHz. Thus, as will be understood from the device table shown inFIG. 2, each of the first and second control units31and32is capable of operating any of the devices by itself.

FIG. 3shows a function table, which is stored in the HDD34, for example. The function table identifies devices required for each function. Specifically, in the PC print function, the network I/F21receives print data from the terminal device10, and the image processing unit38image-processes the print data (expands the print data into bitmap data, for example), and the printing unit39forms a print-object image on a recording medium. Thus, the network I/F21, the image processing unit38, and the printing unit39are required for the PC print function.

In the copy function, the operation unit35accepts a copy request from a user, and the scanner unit36generates scanned data by scanning an original, and the image processing unit38image-processes the scanned data, and the printing unit39prints a scanned image on a recording medium. Thus, the operation unit35, the scanner unit36, the image processing unit38, and the printing unit39are required for the copy function.

In the scanner function, the operation unit35accepts a scan request from a user, and the scanner unit36generates scanned data of an original. Thus, the operation unit35and the scanner unit36are required for the scanner function. In the facsimile communication function, the operation unit35accepts a facsimile communication request from a user, and the facsimile unit37exchanges facsimile data between a remote facsimile device. Thus, the operation unit35and the facsimile unit37are required for the facsimile communication function. In the facsimile print function, the operation unit35accepts a facsimile print request from a user, and the printing unit39forms an image on a recording medium based on previously-received facsimile data. Thus, the operation unit35and the printing unit39are required for the facsimile print function.

The printer30has a high-speed mode, a power-saving mode, and a sleep mode. A user can select one of the high-speed mode and the power-saving mode through manipulation on the operation unit15or35, and the second control unit32stores selected mode settings into the HDD34, for example, thereby setting the printer30to the selected mode.

When the printer30is in the high-speed mode, both the first control unit31and the second control unit32are in the running state and control each of the devices in cooperation with each other. Thus, the first control unit31and the second control unit32can execute at a high speed even functions that impose heavy load. When the printer30is in the power-saving mode, on the other hand, the first control unit31is in a sleep state, and only the second control unit32is in the running state and controls each device by itself. This saves power consumption while keeping each function executable in the power-saving mode.

The printer30enters the sleep mode from either the high-speed mode or the power-saving mode when a predetermined condition to enter the sleep mode is met. The predetermined condition may be such that a predetermined time duration elapses without print data is received from the terminal device10nor facsimile data is received from a remote facsimile device. When a user performs a predetermined operation on the operation unit35or the terminal device10while the printer30is in the sleep mode, then the printer30returns to either the high-speed mode or the power-saving mode. When the printer30is in the sleep mode, none of the functions are executable. In this aspect, the sleep mode differs from the high-speed mode and the power-saving mode.

A function execution process will be described with reference to the flowchart shown inFIG. 4. The function execution process is executed upon receiving a job command. More specifically, when a user operates the operation unit35or the terminal device10to input an execution command for any of the above-mentioned functions of the printer30, then the second control unit32detects an instruction signal generated based on the execution command. As a result, the function execution process is executed based on a program stored in the ROM31B, for example. The function execution process is executed by either the first and second control units31and32or the second control unit32by itself.

In the function execution process, first in S1, the second control unit32(the second CPU32A) determines whether or not the printer30is in the power-saving mode based on the selected mode settings stored in the HDD34.

If it is determined in S1that the printer30is in the high-speed mode (S1:No), then in S3the second control unit32executes in a cooperative execution mode a function corresponding to the execution command (hereinafter referred to as “target function”) in cooperation with the first control unit31at a high speed, and ends the current process.

For example, if the target function is the PC print function, then in S3the second control unit32controls the network I/F21and the printing unit39, and the first control unit31controls the image processing unit38, so a print data receiving process under the control of the second control unit32and the image-processing process under the control of the first control unit31are executed in parallel, and the image-processing process under the control of the first control unit31and a printing process under the control of the second control unit32are executed in parallel. Thus, the PC print function can be executed at a higher speed than in the power-saving mode described later.

Also, if the target function is the copy function, then in S3the second control unit32controls the operation unit35and the image processing unit38, and the first control unit31controls the scanner unit36and the printing unit39, for example. As a result, the copy function can be executed at a higher speed than in the power-saving mode. Although the first and second control units31and32may also execute each of the scanner function, the facsimile communication function, and the facsimile print function in cooperation with each other, either the first control unit31or the second control unit32executes each of these functions by itself in this embodiment.

Note that allocation of the devices to the first and second control units31and32is not limited to that described above. The devices may be allocated not to exceed the maximum operating frequency (i.e., 100 MHz, in this embodiment) of each control unit31,32. For example, if the target function is the PC print function, then the second control unit32may control the network I/F21and the image processing unit38, and the first control unit31may control the printing unit39.

By allocating in this manner, each of the first and second control units31and32can control the device(s) within the maximum operating frequency, so each of the control units31and32can control a device regardless of whether the other of the control units31and32is controlling a different device at the same time. In other words, a device can perform operations independently from operations by different devices.

If it is determined in S1that the printer30is in the power-saving mode (S1:Yes), then in S5the second control unit32determines whether or not the target function is a heavy load function. If so (S5:Yes), then the second control unit32proceeds to S7. On the other hand, if the target function is a light load function (S5:No), then the second control unit32proceeds to S11.

Note that the heavy load function is a function that is executed by operating devices of relatively high operating frequencies. Examples of the heavy load function include the PC print function, the copy function, and the facsimile print function. On the other hand, the light load function is a function that can be executed by only operating devices of relatively low operating frequencies, and examples include the scanner function and the facsimile communication function.

In S11, the second control unit32executes in a solo execution mode the target function (light load function) by itself at substantially the same speed as in the high-speed mode, and then ends the current process. Because the light load function is executable by only operating devices of relatively low operating frequencies as described above, a load in executing the light load function is relatively small. Thus, the second control unit32can execute the target function (light load function) at a high speed even by itself.

In S7, the second control unit32determines whether a load in processing image data corresponding to the target function is heavy, based on attribute information of the image data. The second control unit32determines in S7that the load in processing the image data is heavy if any of attributes of the image data (resolution, data amount, number of toner colors, and the like) is equal to or greater than a predetermined threshold value, and determines that the load in processing the image data is light if each of the attributes is less than the predetermined threshold value.

If a positive determination is made in S7(S7:Yes), then in S9the second control unit32executes in the solo execution mode the target function (heavy load function) at a lower speed than that in the high-speed mode by itself, and ends the current process. That is, because the heavy load function needs a device of high operating frequency to operate as described above, a load in executing the target function (heavy load function) is relatively heavy. Also, the load in processing the image data is also heavy. Thus, the second control unit32cannot execute the heavy load function at a high speed by itself.

For example, the second control unit32controls in S9the sheet-conveying mechanism40to convey a recording sheet at a lower speed than that in the high-speed mode. Lowering the conveying speed further reduces power consumption. Also, lowering the conveying speed enables the fixing unit41to thermally fix the toner images onto the recording sheet at a lower heat (temperature). Thus, the second control unit32controls the fixing unit41to generate lower heat (temperature) than for in the high-speed mode. Lowering the amount of heat further reduces power consumption.

On the other hand, if a negative determination is made in S7(S7:No), then the second control unit32proceeds to S11described above. In this case, a load in executing the heavy load function is relatively heavy, but a load in processing the image data is relatively light. Thus, the second control unit32can execute the heavy load function at a high speed by itself. Thus, the second control unit32controls the sheet-conveying mechanism40to convey a recording medium at substantially the same speed as in the high-speed mode and controls the fixing unit41to generate as much heat as in the high-speed mode.

As described above, according to the present embodiment, in the high-speed mode, i.e., when neither the first control unit31nor the second control unit32has decreased in the operating capability, the first control unit31and the second control unit32control the devices in cooperation with each other, so functions can be executed at a high speed. On the other hand, in the power-saving mode, i.e., when the operating capability of the first control unit31has decreased, the second control unit32controls the devices by itself. Thus, the functions that can be executed in the power-saving mode are not limited, enhancing the convenience.

It is conceivable to always set an operation speed of each device to a lower speed for the solo execution mode, regardless of the magnitude of load in executing each function. However, in this case, execution of function may be always slow. According to the present embodiment, however, the operation speed is set to a lower speed only if the load in executing the target function is heavy, preventing the operation speed from being lowered unnecessarily.

Second Embodiment

Next, a second embodiment of the invention will be described. In this embodiment, the printer30enters the power-saving mode from the high-speed mode immediately after any function is executed in the high-speed mode, and waits in the power-saving mode until a new job command is received. Also, the printer30records one of the high-speed mode and the power-saving mode selected by the user as a selected mode in the HDD34, for example.

A function execution process according to the second embodiment will be described with reference to the flowchart ofFIG. 5. The function execution process ofFIG. 5is started upon receiving a job command for a job (current job). The printer30is in the power-saving mode at the time of when the function execution process is started.

First in S100, the second control unit32(the second CPU32A) determines whether or not the selected mode stored in the HDD34is the power-saving mode. If not (S100:No), then in S102the second control unit32sets the first control unit31into the running state, so the printer30enters the high-speed mode. Next in S104, the first and second control units31and32together process the job (printing, copying, facsimile transmission, or the like) at a higher processing speed. That is, the second control unit32executes in the cooperative execution mode the current job in cooperation with the first control unit31at the high speed. Then, in S106, the second control unit32sets the first control unit31to the sleep state. Note that when the first control unit31is set to the sleep state, the first control unit31enters a standby state in which the first control unit31waits for an interruption signal. Alternatively, at least some clocks are not supplied to the first control unit31, or still alternatively power to the first control unit31is cut off partially or completely. As a result, the printer30enters the power-saving mode. Then, the second control unit32ends the function execution process.

On the other hand, if the selected mode is the power-saving mode (S100:Yes), then in S112the second control unit32determines whether or not the current job is listed on a job list shown inFIG. 6.

The job list indicates jobs that the second control unit32can only process in a reduced processing speed by itself. In this embodiment, the jobs listed on the job list are color copy, color PC printing, monochromatic high-resolution PC printing, and multi-tone image reading. The job list is stored in the HDD34, for example.

If a positive determination is made in S112(S112:Yes), then in S114the second control unit32sets the scanner unit36and the printing unit39into a reduced-speed mode, i.e., sets the processing speed to the reduced processing speed. Then, in S116, the second control unit32executes the current job at the reduced processing speed. That is, the second control unit32executes in the solo execution mode the current job at the lower speed Next, in S118, the second control unit32sets the scanner unit36and the printing unit39into a normal-speed mode, i.e., sets the processing speed to the higher processing speed. Then, the second control unit32ends the function execution process.

On the other hand, if a negative determination is made in S112(S112:No), this means that the second control unit32can execute the current job at the higher processing speed by itself, so in S120the second control unit32executes the current job at the higher processing speed. That is, the second control unit32executes in the solo execution mode the current job at the high speed by itself. Then, the second control unit32ends the function execution process.

As described above, according to the second embodiment, the printer30waits for a next job command in the power-saving mode regardless of whether the high-speed mode or the power-saving mode is selected by the user. If the selected mode is the power-saving mode, and if the current job is listed on the job list shown inFIG. 6, this means that the second control unit32alone (the printer30in the power-saving mode) cannot execute the current job at the higher processing speed. Thus, in this case, the second control unit32executes the current job at the reduced processing speed. More specifically, a sheet feeding speed in which the sheet-conveying mechanism40of the printing unit39feeds recording sheets and a scanning speed in which the scanner unit36scans images on original are reduced. Reducing the processing speed reduces the data amount that the second control unit32needs to process in unit of time and thus enables the second control unit32to execute the current job by itself.

Note that the higher processing speed is a speed at which the second control unit32cannot process by itself, and the reduced processing speed is a speed at which the second control unit32can process by itself and is lower than the higher processing speed. The first and second control units31and32, i.e., the printer30in the high-speed mode, can process at the higher processing speed.

Third Embodiment

Next, a third embodiment of the invention will be described. In the above-described second embodiment, the processing speed is reduced if the current job is listed on the job list. However, in the third embodiment, the processing speed is reduced if the current job includes a process that imposes relatively heavy load. Details will be described next.

A function execution process according to the third embodiment will be described with reference to the flowchart ofFIG. 7. The function execution process ofFIG. 7is similar to the function execution process ofFIG. 5, but differs in including processes of S200to S218instead of the process of S112.

In the function execution process ofFIG. 7, if it is determined in S100that the selected mode is the power-saving mode (S100:Yes), then in S200the second control unit32detects processes included in the current job. Then in S212the second control unit32determines whether or not the processes detected in S200include a color printing process. If so (S212:Yes), then the second control unit32proceeds to S114. On the other hand, if not (S212:No), then in S214the second control unit32determines whether or not the processes detected in S200include a monochromatic high-resolution PC printing process. If so (S214:Yes), then the second control unit32proceeds to S114. On the other hand, if not (S214:No), then in S216the second control unit32determines whether or not the processes detected in S200includes a multi-tone image reading process. If so (S216:Yes), then the second control unit32proceeds to S114. On the other hand, if not (S216:No), then in S218the second control unit32determines whether or not the processes detected in S200include a printing process and an image reading process. If so (S218:Yes), then the second control unit32proceeds to S114. On the other hand, if not (S218:No), then the second control unit32proceeds to S120.

According to this embodiment, if the current job includes any process that imposes relatively heavy load or if the current job includes a predetermined combination of processes, then the current job is executed in the reduced processing speed in the power-saving mode.

For example, in the above-described embodiments, the printer30which is a multifunction device is described as an example of image processing device. However, the image processing device is not limited to the printer30, but may be a printer without scanner function or facsimile function, a facsimile device, or an image processing device, as long as the device can execute a plurality of functions on image data. Also, the image processing device may be an inkjet-type image forming device.

In the above-described embodiments, the copy function, the scanner function, the facsimile communication function and the like are described as functions of the image processing device. However, this is not limitation of the invention. The image processing device may have an image storing function for storing image data into the HDD34and/or a specific image extracting function for extracting a specific image from scanner data, for example, as long as the function is to be executed on image data.

In the above-described embodiments, either the cooperative execution mode or the solo execution mode is selected based on the mode (the high-speed mode or the power-saving mode) selected by the user. However, either the cooperative execution mode or the solo execution mode may be automatically selected based on whether a predetermined switching condition is met. For example, users or time and/or date may be registered for each of the cooperative execution mode and the solo execution mode, and these modes may be switched therebetween based on a user or a time and/or date. Alternatively, the solo execution mode may be selected when the control capability of the first control unit31has decreased. The control capability of the first control unit31may decrease when the first control unit31starts malfunctioning, for example. In this case, it is conceivable to provide a detecting unit (watch dog, for example) for detecting whether or not the first control unit31is running normally based on a number of clocks outputted from the first control unit31, and to have the second control unit32determine whether the first control unit31is malfunctioning based on the detection results from the detecting unit.

In the above-described embodiments, the first control unit31and the second control unit32have substantially the same performance level. However, the first control unit31and the second control unit32may have different performance levels. For example, the first control unit31may have the operating frequency of 200 MHz and function as a main control unit, and the second control unit32may have the operating frequency of 10 MHz and function as a sub-control unit.

In the above described embodiment, the printer30having the two control units (31,32) are described as an example of the image processing device. However, the image processing device may have more than two control units. For example, at least two of more than two control units may execute functions in the cooperative execution mode in the high-speed mode, and less number of control units (excluding a control unit with decreased control capability) may execute in the solo or cooperative execution mode in the power-saving mode.

In the above-described embodiments, the first control unit31and the second control unit32control different devices in the cooperative execution mode. However, the first control unit31and the second control unit32may share in the control of the same devices (the image processing unit38and the printing unit39, for example). For example, the first control unit31may execute image processing on part of image data (expansion into bitmap data, for example), and the second control unit32may execute the image processing on the rest of the image data at the same time.

In the above-described first embodiment, it is determined whether the load in processing image data is heavy (S7) only when it has been determined that the load in executing the target function is heavy (S5:Yes). However, determination on whether the load in processing image data may be made even if it has been determined that the load in executing the target function is light, and the target function may be executed in the solo execution mode at one of different speeds selected based on whether the load is heavy or light. Alternatively, the target function may be executed in the solo execution mode at one of different speeds selected based on magnitude of total load determined based on combination of the load in executing the target function and the load in processing image data.

In the above-described embodiments, the target function is executed either one of two different speeds. i.e., high speed or low speed depending on the magnitude of loads. However, the target function may be executed at a speed selected from among three or more different speeds. Also, in the above-described embodiments, the sheet conveying speed is described as an example of operation speed that changes depending on the mode. However, a scanning speed of a scan head (not shown) of the scanner unit36may be changed as the operation speed depending on the mode.

The printer30described above has three different modes, i.e., the high-speed mode, the power-saving mode, and the sleep mode. However, the printer30may have more than three modes. For example, the printer30may have a medium speed mode in addition to these three modes and execute functions at different speeds in each mode (excluding the sleep mode).