JP3832702B2 - Printing system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing system capable of printing by sharing data processing between a host computer and a printer.
[0002]
[Prior art]
Print data generated on the host computer is transmitted to the printer via a network or the like. The printer generates print image data by interpreting the print data and performing predetermined image processing. Printing is performed by controlling the drive of the print engine based on the printing image data.
[0003]
For example, consider a case where image data compressed in a JPEG (Joint Photographic Experts Group) format is printed by a color inkjet printer or the like from a host computer such as a digital camera. First, the printer decodes the compressed image data according to a predetermined algorithm, and restores the image data. Next, color conversion of the restored image data is performed. That is, the RGB data used as the display color space is converted into CMY data for printing. Further, multi-value data expressed in the CMY color space is converted into binary data based on a predetermined algorithm (halftone process). This CMY binary data is sent to the print engine. The print engine performs printing by ejecting ink droplets of a predetermined color at a predetermined position. In addition to the above processing, various types of image processing such as image rotation, resolution conversion, enlargement, and reduction are appropriately performed.
[0004]
[Problems to be solved by the invention]
Incidentally, as described above, in a printing system including a host computer and a printer, printing image data is generated by performing various image processes on the printer side. That is, on the host computer side, the printing process ends when transmission of print data that can be interpreted by the printer is completed, and the subsequent processing is mostly left to the printer side. Therefore, the printer needs to have all necessary image processing functions. The higher the function of the printer, the more image processing functions to be mounted. In order to realize the required image processing function, an application specific integrated circuit (ASIC) is mounted on a hardware circuit, or a high-performance arithmetic processing unit (CPU) is required. Therefore, the hardware load on the printer side tends to increase. Also, the printing speed is reduced.
[0005]
On the contrary, there is also a method in which most image processing is executed on the host computer side, and the processing result is transmitted to the printer as print data. This is a so-called sleek type or dumb printer system. In this case, since most of the image processing is executed, the data processing load on the printer side is small. However, the processing load on the host computer side increases. Therefore, when a host computer with relatively low processing capability is used, the time until print data is generated is greatly increased, and the printing speed is reduced.
[0006]
In particular, in recent years, so-called direct printing, in which image data generated by a digital camera or the like is directly transmitted to a printer without using a personal computer or the like for printing, is becoming widespread. In this case, since the host computer is a digital camera or the like and the processing capability is relatively small, it is difficult to leave all image processing to the host computer. Moreover, as described above, if all image processing is left to the printer side, the burden on the printer side increases.
[0007]
The present invention has been made in view of the problems as described above, and an object of the present invention is to reduce the burden on the printer by effectively using the data processing resources of the host computer and the printer, respectively. It is to provide a printing system that can. Another object of the present invention is to share the necessary image processing between the host computer and the printer so as to reduce the respective burdens and to improve the printing speed by performing image processing in parallel. It is to provide a printing system.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, data processing is shared by the printer actively using data processing resources on the host computer side.
[0009]
That is, a printing system according to the present invention includes a host computer that generates and transmits print data, and a printer that performs printing based on the print data transmitted from the host computer. Image processing means for generating image data for printing by executing predetermined image processing functions based on the print data, and detecting an image processing function executable on the host computer side from among the predetermined image processing functions Detecting means; requesting means for causing the host computer to execute the detected image processing function and requesting a processing result; and printing means for performing printing based on printing image data generated by the image processing means And the host computer has the executable image processing function. And response means for transmitting to said detecting means, in response to a request from said request means is characterized by being configured to include a transmitting means for transmitting the processing result.
[0010]
Examples of the “host computer” include a personal computer, a workstation, a digital camera, a digital video camera, and a scanner. Examples of the “printer” include an ink jet printer and a laser printer. “Predetermined image processing function” means a data processing function necessary for generating image data for printing. Specifically, for example, a compressed data restoration function, a color conversion function, a halftone function, and an image rotation function An interpolation function, a thinning function, a resolution conversion function, and the like can be given. Actually required image processing functions differ for each print job. The image processing function can be realized as software or hardware.
[0011]
Before printing, the printer inquires whether there is an image processing function available on the host computer side. If the image processing function on the host computer can be used, the host computer is requested to execute predetermined data processing. The result of the data processing is transmitted to the printer. On the printer side, printing image data is generated and printed based on the processing result on the host computer side. Accordingly, it is possible to perform image processing for generating image data for printing using both the image processing function on the host computer side and the image processing function on the printer side. Therefore, it is possible to prevent the processing load from being biased to either the host computer or the printer. Further, when viewed from the whole printing system, the image processing on the host computer side and the image processing on the printer side are executed in parallel, so that the printing time can be shortened.
[0012]
The detection unit can also acquire print summary information indicating a summary of print contents from the host computer, and detect an image processing function executable on the host computer side based on the print summary information.
[0013]
“Print summary information” means information indicating an outline of print contents, specifically, image processing required for generating image data for printing, such as the type of compression algorithm, the number of images, and the paper size. This means information that contains information necessary to specify the function. The detection unit can detect a necessary image processing function on the host computer side based on the print summary information.
[0014]
The detection means can also detect an image processing function that can be executed on the host computer side each time a predetermined amount of data processing by the image processing means is executed.
[0015]
Here, examples of the “predetermined amount” include data processing for one band in the case of a serial printer, and data processing for one page in the case of a page printer. Each time a predetermined amount of data is processed, the detecting means detects an image processing function that can be executed on the host computer side. Thereby, even when the image processing function on the host computer side becomes unusable, it is possible to prevent the printing process from being interrupted.
[0016]
The response means can also reject the use of the image processing function used on the host computer side among the image processing functions executable on the host computer side.
[0017]
Even when an image processing function that can be used on the host computer side is detected, the response means can refuse to use it. Thus, when the host computer side needs an image processing function for another data processing, the image processing function can be used on the host computer side.
[0018]
The predetermined image processing function includes at least a compressed image data restoration function, and the request unit can request the host computer to perform the compressed image data restoration process.
[0019]
For example, examples of compressed image data include JPEG data and GIF data.
[0020]
The present invention can also be expressed as a printer, a printer control method, and a host computer. It can also be understood as a recording medium on which a computer program is recorded. The program can be fixed to various tangible recording media such as a hard disk, a floppy disk, and a memory. In addition, the communication medium is not limited to this, and a communication medium can be used, such as downloading a predetermined program from a server on the network.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0022]
1. First Embodiment FIGS. 1 and 2 relate to a first embodiment of the present invention, and FIG. 1 is a block diagram of the entire printing system.
[0023]
The host computer 1 configured as a digital camera includes an imaging unit 2, an image processing unit 3, a print data generation unit 4, a communication interface (hereinafter abbreviated as "I / F") 5, a response unit 6 and a function management table 7. I have.
[0024]
Digital image data picked up by the image pickup unit 2 including a CCD element or the like is input to the image processing unit 3. The image processing unit 3 performs predetermined processing such as color correction and compression on the image data. The processed image data is converted into print data by the print data generation unit 4. Specifically, for example, print data is generated by adding predetermined header information or the like to processed image data. The generated print data is transmitted from the I / F 5 to the printer 11 to be described later via the communication line CN. The communication line CN can be realized as, for example, a serial cable, a parallel cable, or infrared communication.
[0025]
The response unit 6 as “response means” detects and responds to an image processing function available on the printer 11 side by searching the function management table 7 in response to an inquiry from the printer 11. In the function management table 7, the image processing functions G1 to G3 are stored in association with information on availability or the like. Examples of the image processing functions G1 to G3 include a compressed image data restoration function, a color conversion function, a halftone processing function, an image rotation function, an image interpolation process, and a thinning process. Each image processing function is set with a flag indicating whether it can be used. The image processing function in which the usable flag is set can be activated upon receiving a request from the printer 11. The image processing function in which the unusable flag is set cannot be used by the printer 11. Although only three image processing functions G1 to G3 are shown for convenience of explanation, the present invention is not limited to this.
[0026]
For example, the printer 11 configured as a color inkjet printer includes a printer controller 12, an engine controller 13, and a print engine 14. The printer controller 12 includes a communication I / F 15, an input buffer 16, an image processing unit 17, an output buffer 18, and a control unit 19. The print data transmitted from the communication line CN via the I / F 15 is stored in the input buffer 16. The image processing unit 17 interprets the print data read from the input buffer 16 and generates image data for printing by executing the image processing functions G1 to G3 in a predetermined order.
[0027]
The control unit 19 adjusts the operation of the image processing unit 17 on the printer 11 side and the operation of the image processing unit 3 on the host computer 1 side. The control unit 19 includes a function detection unit 20 as a “detection unit” and a processing request unit 21 as a “request unit”. In addition, although not shown, the control unit 19 also implements “transmission means”. When printing is instructed from the host computer 1, the function detection unit 20 inquires about image processing functions that can be used on the host computer 1 side. When the response unit 6 of the host computer 1 answers this inquiry, the processing request unit 21 determines image processing to be requested to the host computer 1 side. The image processing unit 17 generates print image data based on the processing result executed by the image processing unit 3 of the host computer 1.
[0028]
FIG. 2 is a flowchart showing the operation of the present embodiment. In the following description, step is abbreviated as “S”. The left side of the drawing shows processing executed on the printer 11 side, and the right side of the drawing shows processing executed on the host computer 1 side.
[0029]
When printing is instructed, the function detection unit 20 of the printer 1 requests the host computer 1 to transmit print summary information (PS1). The print summary information includes, for example, the number of images to be printed (number of objects), the paper size, and the like. The host computer 1 that has received the print summary information transmission request sends the print summary information prior to sending the print data (HS1). The function detection unit 20 of the printer 11 that has acquired the print summary information identifies a predetermined image processing function required for the current printing based on the print summary information, and the host computer is configured for all or a part of each of the predetermined functions. An inquiry is made as to whether or not the image processing function on one side can be used (PS2). Here, it is not necessary to make an inquiry to the host computer 1 for all of the required predetermined image processing functions. For example, it is possible to inquire only about a preset function such as a compressed image data restoration function.
[0030]
Upon receiving the inquiry about the image processing function, the response unit 6 of the host computer 1 refers to the function management table 7 and answers the image processing function installed on the host computer 1 side (HS2). The function detection unit 20 of the printer 11 inquires whether a desired image processing function can be used (PS3). In response to this inquiry, the response unit 6 of the host computer 1 replies whether it can be used or not by referring to the flag of availability (HS3). It should be noted that when the image processing function installed on the host computer 1 side is answered, it is possible to respond including the availability status. In this case, PS3 and HS3 are omitted.
[0031]
The processing request unit 21 of the printer 11 determines whether or not a desired image processing function can be used (PS4). If the desired image processing function can be used, execution of the image processing is sent to the host computer 1 side. Request (PS5). For convenience of explanation, it is assumed here that the host computer 1 is requested to execute G1 among the image processing functions G1 to G3. The image processing unit 3 of the host computer 1 requested to execute the image processing function G1 executes the image processing G1 requested for the image data (HS4). The result of this data processing is transmitted to the printer 11 side (HS5).
[0032]
Then, the image processing unit 17 of the printer 11 further performs image processing G2 and G3 on the processing result of the image processing G1, and generates print image data (PS8 and PS9). The image data for printing thus generated is input to the engine controller 13 and printed (PS10). On the other hand, when the image processing function G1 on the host computer 1 side cannot be used (PS4: NO), print data is received from the host computer 1 (PS6), and the image processing unit 17 on the printer 11 side executes the image processing G1. (PS7). Therefore, in this case, all the image processing required for generating the print image data is executed on the printer 11 side.
[0033]
On the printer 11 side, the processes after PS3 are repeated until all printing is completed (PS11). On the other hand, on the host computer 1 side, the processes after HS3 are repeated until the transmission of the print data is completed (HS6).
[0034]
The embodiment configured as described above has the following effects.
[0035]
First, since image processing is shared between the host computer 1 and the printer 11, the processing load on the printer 11 side can be reduced.
[0036]
Second, since the host computer 1 and the printer 11 perform image processing in parallel, the time required for data processing can be shortened and the printing speed can be improved.
[0037]
Thirdly, since the host computer 1 and the printer 11 perform data processing using mutual data processing resources (image processing functions), high-performance printing is realized even when the processing capacity of the host computer 1 is low. be able to. Therefore, this embodiment is particularly useful in the case of direct printing in which data is directly transmitted from a digital camera to a printer for printing as in the present embodiment.
[0038]
Fourth, when the unusable flag is set in the image processing function on the host computer 1 side, the image processing function cannot be used on the printer 11 side. Therefore, when the image processing function is used for other data processing on the host computer 1 side, it can be used promptly.
[0039]
2. Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. In the following embodiments, the same components as those described above are denoted by the same reference numerals, and the description thereof is omitted. In this embodiment, a specific processing method when printing compressed image data is shown.
[0040]
FIG. 3 is a flowchart of the printing process according to this embodiment. When printing is instructed, the printer 11 acquires print summary information such as the number of images to be printed, that is, the number of image objects, the paper size, and the compression algorithm (data format) from the host computer 1 (S1). Next, a layout for generating image data for printing is set based on the acquired number of image objects and the like (S2).
[0041]
Then, the process request unit 21 determines whether a restoration function for restoring the compressed image data is available (S3). That is, the host computer 1 is inquired about the presence / absence of the restoration function and the availability of the use. If the compressed image data restoration function is available, the host computer 1 is requested to transmit the restored RGB raster data (S4). The RGB raster data restored on the host computer 1 side is transmitted line by line or line by line (S5). Upon receiving the RGB raster data, the image processing unit 17 of the printer 11 executes color conversion processing (S9) and halftone processing (S10) corresponding to “residual image processing” in units of bands. The print data generated thereby is input to the engine controller 13 and printed (S11). The processes of S3 to S11 are repeated until all the image objects are printed (S12).
[0042]
If the host computer 1 cannot use the restoration function itself to request processing from the host computer 1 side (S3: NO), send compressed image data (here, JPEG data) to the host computer 1 Is requested (S6). Then, the compressed image data received from the host computer 1 is restored by the image processing function of the image processing unit 17 on the printer 11 side, and stored in the output buffer 18 that stores in band units (S7). The processes of S6 to S8 are repeated until data for one band is restored (S8).
[0043]
Also in the present embodiment configured as described above, the same effects as those of the first embodiment described above can be obtained. FIG. 4 shows a state of parallel processing according to the present embodiment. As shown in FIG. 4, when the printer 11 requests RGB raster data for the first band, the host computer 1 restores compressed image data corresponding to the first band and transmits it to the printer 11. The printer 11 that has received the first band of RGB raster data requests transmission of the second band of RGB raster data, and performs color conversion processing, halftone processing, and the like on the already received first band of RGB raster data. Therefore, the first band can be printed while the host computer 1 side restores the compressed image data of the second band. Similarly, since the printer 11 and the host computer 1 operate in parallel, the print processing time can be shortened.
[0044]
A person skilled in the art can make various additions, changes, combinations, and the like within the scope of the present invention described in the above embodiments. For example, as shown in FIG. 5A, the image processing G1 and G3 may be executed on the host computer 1 side, and the intermediate image processing G2 may be executed on the printer side. Alternatively, the image processing G1 and G2 may be executed first on the printer 11 side, and the last image processing G3 may be executed on the host computer 1 side. However, in the case of FIG. 5A, since the data transfer amount between the printer 11 and the host computer 1 increases, the processing speed may not be significantly improved although it depends on the contents of the image processing. There is sex.
[0045]
In each of the above embodiments, JPEG is exemplified as the format of the compressed image data, but the present invention is not limited to this.
[0046]
【The invention's effect】
As described above, according to the printing system of the present invention, the image processing function of the printer and the image processing function on the host computer side can be operated in parallel, so the print processing speed can be reduced. it can. Further, since the image processing function installed on the host computer side is used, the processing load on the printer side can be reduced. Further, even when a host computer having a low processing capability such as a digital camera is used, highly functional printing can be performed in a relatively short time.
[Brief description of the drawings]
FIG. 1 is a block diagram of a printing system according to a first embodiment of the present invention.
FIG. 2 is a flowchart illustrating a printing process.
FIG. 3 is a flowchart showing a printing process according to a second embodiment of the present invention.
FIG. 4 is an explanatory diagram schematically illustrating the operating states of a printer and a host computer.
FIG. 5 is an explanatory diagram showing another example of sharing image processing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Host computer 3 Image processing part 4 Print data generation part 5 Communication interface 6 Response part 7 Function management table 11 Printer 12 Printer controller 13 Engine controller 14 Print engine 15 Communication interface 17 Image processing part 19 Control part 20 Function detection part 21 Processing request Part

Claims (12)

In a printing system comprising a host computer that generates and transmits print data, and a printer that performs printing based on the print data transmitted from the host computer,
The printer is
Image processing means for generating image data for printing by executing predetermined image processing functions based on the print data, and
Detecting means for detecting an image processing function executable on the host computer side among the predetermined image processing functions;
Request means for causing the host computer to execute the detected image processing function and requesting a processing result;
Printing means for performing printing based on the image data for printing generated by the image processing means,
The host computer
Response means for transmitting the presence or absence of the executable image processing function to the detection means;
A printing system comprising: a transmission unit that transmits the processing result in response to a request from the request unit. The detection means acquires print summary information including information necessary for specifying an image processing function required for generating print image data from the host computer, and the host computer side based on the print summary information The printing system according to claim 1, wherein an image processing function executable by the printer is detected.   3. The printing system according to claim 1, wherein the detection unit detects an image processing function executable on the host computer side each time a predetermined amount of data processing by the image processing unit is executed. .   The printing system according to any one of claims 1 to 3, wherein the response unit rejects use of an image processing function used on the host computer side among image processing functions executable on the host computer side.   The predetermined image processing function includes at least a compressed image data restoration function, and the request unit requests the host computer to restore the compressed image data. Printing system according to. In a printer that performs printing based on print data received from a host computer,
Image processing means for generating image data for printing by executing predetermined image processing functions based on the print data, and
Detecting means for detecting an image processing function executable on the host computer side among the predetermined image processing functions;
Request means for causing the host computer to execute the detected image processing function and requesting a processing result;
Receiving means for receiving the processing result;
A printer comprising: printing means for performing printing based on image data for printing generated by the image processing means. The detection means acquires print summary information including information necessary for specifying an image processing function required for generating print image data from the host computer, and the host computer side based on the print summary information The printer according to claim 6, wherein an image processing function executable by the printer is detected. 8. The printer according to claim 6 , wherein the detection unit detects an image processing function that can be executed on the host computer side each time a predetermined amount of data processing by the image processing unit is executed. In a printer control method for printing by sharing image processing between a host computer and a printer,
Detecting an image processing function executable on the host computer side among predetermined image processing functions used for generating print image data;
Requesting the host computer to execute the detected image processing function;
Receiving a processing result on the host computer side;
Generating the printing image data by causing the remaining image processing functions to be executed among the predetermined image processing functions based on the received processing results;
Printing based on the generated image data for printing;
A printer control method comprising: The method further comprises the step of acquiring print summary information including information necessary for specifying an image processing function required for generating image data for printing from the host computer, and the host computer side based on the print summary information The printer control method according to claim 9, wherein an executable image processing function is detected. In a host computer that generates data for transmission to a printer,
In response to an inquiry from the printer, response means for transmitting the presence or absence of image processing that can be executed on the host computer side among predetermined image processing necessary for generating print image data;
Data processing means for executing image processing requested by the printer;
A host computer comprising: a transmission unit that transmits a processing result of the data processing unit to the printer. In a recording medium recording a program for controlling a printer to print based on data received from a host computer,
A function for detecting an image processing function executable on the host computer side among predetermined image processing functions required for generating print image data;
A function of requesting the host computer to execute the detected image processing function;
A function of generating the print image data by executing a remaining image processing function among the predetermined image processing functions based on a processing result on the host computer side;
A function of printing based on the generated image data for printing,
A recording medium on which a program to be realized on a computer is recorded in a form that can be read and understood by the computer.

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