JP2003044235A - Host base printing system and method for controlling the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a host base printing system capable of automatically deciding a bit map developing condition such as the optimal number of color tones and a method for controlling the system. SOLUTION: When a bit map data size generated based on the number of color tones set by a user exceeds the preliminarily estimated maximum printable size (S26), the generated bit map data are destroyed, and the set color tone is lowered by one level, and the bit map is developed again (S27). Then, the color tone is lowered until the regenerated bit map data reach the maximum printable size, and when the bit map data size reaches the printable size, the bit map data are transmitted to a printer so that the print can be executed (S28).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a host-based printing system in which a host computer connected to a printer generates bitmap data of print data and transfers the bitmap data to the printer, and a control method therefor.

[0002]

2. Description of the Related Art Generally, in a host-based printing system, when bitmap data transferred from a host is received, it is stored in a RAM of a printer and the bitmap data is output from the RAM to a printer engine as a video signal. is there. Start the transfer of bitmap data,
If it can be stored in the RAM of the printer to some extent, printing is executed and output of video data is started. After that, while transferring bitmap data, while also outputting video, it is possible to print with a small RAM capacity. It is possible. Further, since the host computer performs bitmap expansion (also called rendering), it is not necessary to mount a high performance CPU on the printer, and it is possible to provide a printing system at low cost.

In the case of a host-based printer equipped with only such a small-capacity RAM, if the data transfer speed from the host to the printer is slow, the video data output to the printer will be lost during printing and printing will fail. Sometimes (the image is cut off in the middle).

In particular, in some color printers such as a color laser printer, a plurality of gradations / density (for example, 256 gradations) can be expressed for each pixel (pixel) unit. The higher the number of color gradations, the higher the quality of the image that can be printed. However, since the amount of bitmap data increases accordingly, the possibility of printing failure increases with low-speed data transfer.

Conventionally, in a color host-based printer, the user has selected an arbitrary value for the color gradation to be printed from the front panel of the printer or the printer driver setting screen on the host computer. The print data is subjected to bitmap expansion (rendering) with the selected color gradation, the generated bitmap data is transferred to the printer, and printing is executed.

[0006]

However, if the user wants to print with the highest possible image quality, it is not appropriate to know what the number of color gradations at which printing is successful with the highest image quality is appropriate. There is a problem that it is not possible to judge whether the printing succeeds or fails unless the number of color gradations is selected and the printing is actually performed.

Further, even with the same print data, the printable color gradation varies depending on the host computer and the interface used, so there is the problem that it is difficult for the user to predict whether printing with a certain color gradation is possible. It was

Further, the same problem as described above is encountered when setting the resolution.

The present invention has been made in view of the above problems in the conventional example, and a host-based printing system capable of automatically determining an optimum bitmap expansion condition such as the number of color gradations and its control. The purpose is to provide a method.

[0010]

To achieve the above object, for example, a host-based printing system of the present invention has the following configuration. That is, a host-based printing system comprising a printer and a host computer connected to the printer, wherein the host computer generates bitmap data of print data and transfers the bitmap data to the printer, the host computer comprising the printing Bit map expanding means for expanding the data into a bitmap with a predetermined number of gradations and resolution, judging means for judging whether or not the bitmap data expanded by the bitmap expanding means can be transferred to the printer, and the judgment. When it is determined that the transfer to the printer is impossible by the means, the bitmap expansion means performs bitmap expansion with the gradation number and / or resolution obtained by subtracting a predetermined number from the current gradation number and / or resolution. And a control means for controlling the control.

[0011]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

<First Embodiment> [Description of Laser Beam Printer (FIG. 1)] First, a configuration of a color laser beam printer to which the present invention can be applied is shown in FIG.
Will be described with reference to.

In FIG. 1, 711 is a scanner,
A laser output unit (not shown) for converting an image signal into an optical signal,
Polyhedron (for example, octahedron) polygon mirror 712, motor (not shown) for rotating this mirror 712, and f /
It has a θ lens (imaging lens) 713 and the like. 714
Is a reflection mirror for changing the optical path of the laser beam, and 715 is a photosensitive drum. The laser light emitted from the laser output unit is reflected on one side surface of the polygon mirror 712, passes through the f / θ lens 713 and the mirror 714, and linearly scans the surface of the photosensitive drum 715 rotating in the direction of the arrow in the drawing (raster). to scan. As a result, an electrostatic latent image corresponding to the original image is formed on the surface of the photosensitive drum 715.

Further, 717 is a primary charger, 718 is a whole surface exposure lamp, 723 is a cleaner portion for collecting the residual toner that has not been transferred, 724 is a pre-transfer charger, and these members are provided around the photosensitive drum 715. It is arranged.

Reference numeral 726 denotes a developing device unit which develops the electrostatic latent image formed on the surface of the photosensitive drum 715 by laser exposure, and has a structure shown below. 731Y, 7
31M, 731C and 731Bk are developing sleeves 730Y and 730 for contacting with the photosensitive drum 715 and directly developing.
M, 730C and 730Bk are toner hoppers for holding the preliminary toner, 732 is a screw for transferring the developer, and these sleeves 731Y to 731Bk,
Toner hopper 730Y to 730Bk and screw 7
It is arranged around the rotation axis P of the developing device unit by 32. It should be noted that the symbols Y, M, and
C and Bk indicate colors. That is, "Y" is yellow, "M" is magenta, "C" is cyan, and "Bk" is black. When forming a yellow toner image,
The yellow toner developing process is performed at the position shown in this figure.

Further, when forming a magenta toner image, the developing device unit 726 is rotated about the axis P in the figure, and the developing sleeve 7 in the magenta developing device is attached to the photoconductor 715.
Make sure that 31M contacts. Cyan and black development work similarly.

A transfer drum 716 transfers the toner image formed on the photosensitive drum 715 onto a sheet.
19 is an actuator plate for detecting the moving position of the transfer drum 716, and 720 is this actuator plate 71.
9, a position sensor that detects that the transfer drum 716 has moved to the home position position by being close to
725 is a transfer drum cleaner, 727 is a paper pressing roller,
Reference numeral 728 denotes a slow charger, 729 denotes a transfer charger, and these members 719, 720, 725, 727, 729 are arranged around the transfer roller 716.

On the other hand, reference numerals 735 and 736 denote paper feed cassettes for accommodating paper sheets (paper sheets). In the embodiment, the paper feed cassette 735 is, for example, A4 size paper, and the paper feed cassette 7.
It is assumed that 36 stores A3 size paper. Reference numerals 737 and 738 are paper feed rollers that feed paper from the cassettes 735 and 736, and 739, 740, and 741 are timing rollers that set timings for paper feed and conveyance. Guide 7
It is guided by 49 and is wound around the transfer drum 716 while being held by the gripper at the tip, and the process proceeds to the image forming process. In addition,
Which of the paper feed cassettes 735 and 736 is selected?
Only the paper feed roller selected and determined by the instruction of the main control unit 31 is rotated.

With the above configuration, full-color printing with four YMCK colors is realized.

[Configuration of Host-Based Color Printing System (FIG. 2)] FIG. 2 is a block diagram of the host-based color printing system according to the embodiment of the present invention. Here, description will be made assuming that the color laser beam printer shown in FIG. 1 is used. As long as the functions of the present invention are executed, the present invention can be applied to a single device, a system including a plurality of devices, or a system in which processing is performed via a network such as a LAN. It goes without saying that the invention can be applied.

In FIG. 2, reference numeral 3000 denotes a host computer for performing document processing in which graphics, images, characters, tables (including spreadsheets, etc.) are mixed based on a document processing program stored in the ROM for programs of the ROM 3. Execute C
The CPU 1 is provided with the PU 1, and the CPU 1 comprehensively controls each device connected to the system bus 4.

Further, the program ROM of the ROM 3
The ROM 3 stores a control program of the CPU 1 and the like.
This font ROM stores font data and the like used in the above document processing, and the data ROM of ROM 3 stores various data used in the above document processing. A RAM 2 functions as a main memory and a work area of the CPU 1.

5 is a keyboard controller (KBC)
Then, key input from the keyboard 9 or a pointing device (mouse) (not shown) is controlled. 6 is a CRT controller (CRTC), which is a CRT display (CR
T) Control the display of 10. Reference numeral 7 is a memory controller (MC), which accesses the external memory 11 such as a hard disk (HD) or a floppy (registered trademark) disk (FD) for storing a boot program, various applications, font data, user files, edit files and the like. To control. 8 is a printer controller (PRTC)
With a predetermined bidirectional interface (interface)
It is connected to the printer 1000 via 21 and executes communication control processing with the printer controller unit 1001.

The CPU 1 executes, for example, an outline font rasterizing process to the display information RAM set on the RAM 2, and the W on the CRT 10 is executed.
It enables YSIWYG. Further, the CPU 1 is C
Open various windows registered based on commands designated by a mouse cursor (not shown) on the RT10,
Performs various data processing.

In the printer 1000, a printer CPU 12 controls access to various devices connected to the system bus 15 on the basis of a control program stored in a program ROM of the ROM 13, and a printing unit. Interface (engine video I / F) 16
Printing mechanism unit (printer engine) 1 connected via
An image signal as output information is output to 7. The program ROM of the ROM 13 stores the control program of the CPU 12 as shown in the flowcharts of FIGS. 4 and 5 described later.

The CPU 12 can perform communication processing with the host computer via the input unit 18, and can notify the host computer 3000 of information in the printer. Reference numeral 19 denotes a RAM that functions as a main memory, a work area, etc. of the CPU 12, and is configured so that the memory capacity can be expanded by an optional RAM connected to an expansion port (not shown). RA
M19 is used as a drawing memory for storing the image bit map data received from the host computer, a video signal ON / OFF information storage area, and other work areas. An operation panel 110 is provided with switches for operation, an LED display, and the like.

FIG. 3 is a functional block diagram showing the processing configuration of the printing function of the printing system in the embodiment, and the same parts as those in the above-mentioned drawings are designated by the same reference numerals.

In FIG. 3, reference numeral 3000 denotes a host computer that functions as a server or a client, for example, and outputs print information including print data and control codes to the printer 1000.

The printer 1000 is roughly divided into a functional unit and a controller unit 100 and an operation panel unit 11.
0, the printing mechanism unit 17. In this embodiment, a color laser beam printer (color LBP) is specifically assumed as the printer 1000. In addition,
The printer to which the present invention can be applied is not limited to the LBP, but may be an inkjet printer or a thermal printer.
It goes without saying that another printing method printer such as a printer may be used.

In the printer 1000, the controller section 100 includes an interface (I / F) section 15 which is a connecting means with the host computer 3000, a reception buffer 101 for temporarily holding and managing reception data, transmission data and the like. A transmission buffer 102 for temporarily holding and managing, and a command analysis unit 10 for analyzing print data.
4, a print control processing execution unit 105, an image control unit 103, an output control unit 107, and the like.

The interface (I / F) unit 15 is a communication means for transmitting / receiving print data to / from the host computer 3000. The print data received through the interface (I / F) unit 15 is sequentially accumulated in the reception buffer 101 which is a storage unit that temporarily holds the data, and the command analysis unit 104 or the image control unit 103 is stored as necessary. Read and processed by. The command analysis unit 104 is composed of a control program conforming to each print control command system and print job control language. The commands analyzed by the command analysis unit 104 are those related to image data such as bitmap data. The image control unit 103 is instructed and processed, and commands other than drawing such as paper feed selection and reset commands are instructed to the print control process execution unit 105 and processed.

The image control unit 103 removes the command portion from the transferred image data command data, and if the image data is compressed, the image control unit 103
The decompression process is performed in and the video data is stored in the video output buffer 106. The video output buffer may be managed by this image data reception processing and the chasing of the output of the video signal to the printing mechanism unit (printer engine) 17, that is, banding control, or if there is sufficient memory, one page An area capable of storing minutes may be reserved as a video output buffer.

The operation panel 110 is for setting / displaying various states of the printer. The output control unit 107 converts the image bitmap data stored in the video output buffer 106 into a video signal, and transfers the video signal to the printing mechanism unit (printer engine) 17.
The printing mechanism unit 17 is a mechanism for forming a permanent visible image on the recording paper by using the received video signal.

Next, the configuration of the host computer 3000 will be described.

The host computer 3000 is constructed as one computer system including the keyboard 9 and the mouse 220 and the display monitor 10. The host computer 3000 is Windows
(Registered trademark), UNIX (registered trademark), MacOS (registered trademark), or any other basic OS.

Focusing only on the functional part relating to the present invention on the host computer side, the functions on the basic OS are roughly classified, and the application software 201 and the graphic device interface which is a part of the basic OS (hereinafter referred to as GDI). ) 202, and the printer driver 20 that performs processing such as the automatic color tone control 205 of the present invention
3. It can be divided into the print spooler 204 that temporarily stores the data generated by the printer driver.

Although these names and functional frameworks may differ slightly depending on the basic OS, as long as they are modules that can realize each technical means referred to in the present invention, those names and frameworks are not so important to the present invention. Not a big problem. Modules called GDI and printer driver are specific to Windows 98 and Windows NT, and can be realized in other basic OSs by modules called a graphic kernel and a print filter, for example. Similarly in the print spooler 204,
It can be realized by incorporating a process in a module called a print queue.

Generally, the host computer 3000 including these components is the CPU shown in FIG.
Under hardware such as 1, RAM2, ROM3, and external memory 11, software called basic software (B
IOS) controls the control, and the application software operates under the basic software. Printer driver 203 which is responsible for automatic color tone control 205 according to the present invention
Is also one of the applied software. In addition, the application software 201 is, for example,
It refers to application software that runs on basic software such as word processors and spreadsheets. Further, a plurality of application software programs are activated at arbitrary timings (varies depending on the main memory capacity), and they are shown as an application 206.

Next, a case where an arbitrary image editing software is used as the application 201 will be described as an example.

The application 201 mainly performs image editing work, and when printing the image, the display monitor 10 is operated by the mouse 220 or the like.
Select the print menu displayed above to execute printing. Next, the application 201 calls the GDI 202 which is a partial function of the basic OS. This GDI2
02 is a basic function group that controls a display device and a print device such as screen display and print output. Application software of each company uses this basic function group to make a part dependent on a model (hardware). It is possible to operate application software without being aware of.

Next, in the GDI 202, the printer driver 203 that manages the information depending on the model of each printing device is used to output the printing device (printer 100 in this case).
A) called from the application software 201 by fetching information such as the drawing ability and print resolution of 0)
The PI function is processed, and the function provided by the printer driver to the GDI 202 is called according to the processing content. This function has a predetermined interface (Device Driver Interface commonly called DDI), and the creator of the printer driver creates the printer driver focusing on the data conversion from this interface to the actual printing device.

The printer driver 203 is the GDI 202.
A print data (image bitmap data) generation process 207 and a printer control command generation process 208 based on the DDI information received from the DDI information and the print environment setting set by the graphical user interface (GUI) of itself. Run the print spooler 2
Send to 04. Further, these data pass through the print spooler 204, the I / F unit 8 and the printer 10.
Will be sent to 00.

Next, the mechanism of print success / failure in the host-based printing system having the above-mentioned configuration will be described.

The amount of bitmap data created by the host computer (external device) increases as the image is more complicated and the resolution and color gradation when the bitmap is developed are higher. Usually, bitmap data is subjected to data compression in order to shorten the transfer time, and the data amount is reduced before being transferred to the printer. Even so, photographic images that do not compress well can reach tens of megabytes at 600 dpi, 64 gradations, and A4 size. Here, if the transfer speed of the input / output I / F between the external device and the printer> the transfer speed of the engine video I / F between the controller and the printing mechanism unit, printing will always succeed regardless of the amount of data. In addition, even if the transfer speed of the input / output I / F between the external device and the printer is smaller than the transfer speed of the engine video I / F between the controller and the print mechanism unit, if the capacity of the video output buffer 106 is sufficient, all After storing the bitmap data of the engine in the video output buffer 106, the engine video I / F 16
It may be transferred to the printing mechanism section 17 through. However, when the printing speed of the engine 17 becomes faster, it is difficult to make the transfer speed of the input / output I / F between the external device and the printer> the transfer speed of the engine video I / F between the controller and the printing mechanism unit sufficient memory. It is also difficult to install the because the cost is high.

Therefore, a certain amount of video output buffer (RAM) 106 is installed, and the bitmap data transferred from the external device (host computer 3000) is stored therein, and when the video output buffer 106 becomes full. , Start printing.

When printing starts, engine video I / F1
Bit map data stored in the video output buffer 106 is transferred to the print mechanism unit 17 through 6. That is, after printing is started, the video output buffer 10
6 is output to the print mechanism unit 17, while data from the external device 3000 is output to the video output buffer 106.
Will be entered into. Here, if the transfer rate of the input / output I / F between the external device and the printer is smaller than the transfer rate of the engine video I / F between the controller and the printing mechanism section, the data in the video output buffer 106 gradually decreases. I will go. This video output buffer 1
The printing is successful if all the bitmap data is transferred from the external device 3000 before the data in 06 becomes 0, but the bitmap data still remains in the external device 3000, but the video output buffer 106 When the inside data becomes 0, the print image is cut off at that point, and the printing fails.

[Description of Operation of Host Computer] FIG. 4
6 is a flowchart showing an initialization process in the process of automatic color gradation control 205 (FIG. 3), which is performed when the power supplies of both the host computer 3000 and the printer 1000 are turned on. The program corresponding to this flow chart is stored in, for example, the ROM 3, and R
It is loaded into AM2 and executed by CPU1.

In this embodiment, the host computer 30
00 and the printer 1000 are both turned on, the size of the video output buffer of the printer 1000 is acquired and the data transfer speed to the printer 1000 is measured.

When the power of the host computer 3000 is turned on and the printer driver 203 is activated, first, in step S11, it is confirmed whether or not the power of the printer 1000 is turned on (whether communication with the printer 1000 is possible). Power supply is OF
If it is F, it waits until it is turned on and communication is possible.

When the power is turned on and communication becomes possible, the process proceeds to step S12, and a command for acquiring the size of the video output buffer 106 is transmitted to the printer 1000. Next, in step S13, the printer 1 for the command
Wait for the status from 000 to be sent,
When the status is received, the process proceeds to step S14. Step S
At 14, the acquired size of the video output buffer 106 is stored and held in the RAM 2.

Next, the data transfer speed is measured.
In step S15, a timer for starting measurement is started.
Then, in step S16, the dummy data is transferred to the printer 100.
Transfer to 0. The dummy data may be implemented as a kind of command, and the printer 1000 may be configured to simply discard the dummy data when it receives the dummy data.

Next, in step S17, the completion of the dummy data transfer is awaited, and when the transfer is completed, step S1
Go to step 8 and stop the timer for time measurement. Then, in step S19, the data transfer speed in the I / F 8,15 in which the host computer 3000 and the printer 1000 are connected is calculated from the measured time and the size of the transferred dummy data, and in the next step S110. The calculated data transfer speed is stored and held in the RAM 2.

Finally, in step S111, the video output buffer 10 of the printer 1000 stored in the RAM 2
From the size of 6 and the data transfer speed, the bitmap data size predicted to succeed in printing is calculated according to the following procedure. However, the procedure shown below is an example, and any method may be used as long as it is calculated (estimated) based on these numerical values.

In the following description, the size of the video output buffer 106 is VBSize, the data transfer rate between the host computer 3000 and the printer 1000 is DS, and the controller 100 is
− Let VS be the transfer rate (video transfer rate) of the engine video I / F 16 between the printing mechanism units 17.

If the video output buffer 106 starts printing when the video output buffer 106 is full of image data, the data stored in the video output buffer 106 decreases at the next speed XS.

XS = VS-DS

At this speed, the data stored in the video output buffer decreases, and the printing fails when it reaches 0. Therefore, conversely, the data size is the limit of printable data. . Therefore, the printable data size (DMax) can be calculated by the following formula.

[0058] DMax = VBSize + (DS * (VBSize / XS))

However, since the image data is generally compressed, VS (that is, the speed of the data leaving the video output buffer 106) is not always constant. Therefore, it is desirable to calculate the maximum printable image data size by adding a certain amount of margin (α) to the predicted value.

DMax = VBSize + (DS * (VBSize
/ XS)) + α

The above is the description of the initialization logic executed when the power supply of both the host computer 3000 and the printer 1000 in this embodiment is turned on and communication is possible.

Then, using the flowchart of FIG.
The main process of the process of the automatic color tone control 205 in this embodiment when printing is actually executed will be described. The program corresponding to this flowchart is also ROM
3 is stored in RAM 3, loaded into RAM 2 when the power is turned on, and executed by CPU 1.

First, when the print execution is instructed in step S21, the print data output from the application is subjected to bitmap expansion (rendering) in step S22. At this time, as the resolution for expanding the bitmap and the color gradation, values specified by the user on the operation panel 110 or the setting screen of the printer driver 203 can be used.

Next, in step S23, the generated bitmap data is subjected to predetermined compression to reduce the bitmap data size. Any data compression method may be used, and no particular compression is required.

At step S24, the automatic high quality mode is turned on.
Check whether it is set to ON or OFF. It is preferable that the user can perform the setting method from the operation panel 110 or the driver setting screen.
If the automatic high-quality mode is OFF, the process immediately proceeds to step S28, the generated bitmap data is transmitted to the printer, and printing is executed. However, in this case,
Printing may fail. This is because it is not guaranteed that the bitmap data generated with the set number of gradations can be printed with that size.

On the other hand, in step S24, the automatic high-quality mode is set to O.
If the result is N, the process proceeds to step S25, and the maximum printable image data size obtained in the initialization process (flow of FIG. 4) is compared with the generated bitmap data size. In step S26, if the maximum printable data size ≧ bitmap data size, it is determined that printing is possible, the process proceeds to step S28, the bitmap data is transmitted to the printer 1000, and printing is executed. On the other hand, if the maximum printable data size is smaller than the bitmap data size, the generated bitmap data is discarded, the process proceeds to step S27, and the set color gradation is reduced by one step (that is, low gradation). Then, the print data is expanded (rendered) again. Here, the color gradation is reduced by one step, but it may be reduced by two steps or three steps. Then, when the bitmap data is generated, the process returns to step S23. Thereafter, steps S23 to S27 are repeatedly executed until the printable bitmap data size is reached, and when the printable bitmap data size is reached, the bitmap data is transmitted to the printer 1000 at step S28 and printing is performed.

As described above, in the conventional color gradation setting by the user, it is not possible to know up to which color gradation the printing is successful until the actual printing is performed. Therefore, the color gradation is gradually reduced until the printing is successful. Therefore, there is a problem in that wasteful printing is performed.

However, according to the above-described embodiment, the maximum printable bitmap data size is obtained, and the gradation is gradually reduced until the printable bitmap size is reached. Without it, it has become possible to automatically perform printing with the highest printable color gradation.

<Second Embodiment> In the first embodiment described above,
Until the printable bitmap data size is reached, the color gradation is gradually reduced and the highest-quality printing that can be printed automatically is executed. However, in some cases, lowering the resolution may reduce the deterioration of the image quality rather than lowering the color gradation. The bitmap data size can also be reduced by reducing the resolution instead of decreasing the number of gradations and performing bitmap expansion (rendering). In view of this, in the present embodiment, not only the color gradation but also the resolution is gradually decreased until the printable bitmap data size is reached, whereby the highest-quality print that can be printed automatically is executed. It is preferable to determine in advance in what order the color gradation / resolution should be gradually reduced. For example, the order is set as shown in the table of FIG. The table shown in FIG. 6 is, for example, RO
It is assumed to be stored in M3.

According to the present embodiment, the print quality is controlled not only in relation to the color gradation but also the relationship with the resolution, so that it is possible to print with the highest quality that enables finer printing.

<Third Embodiment> In the first and second embodiments described above, until the printable bitmap data size is reached,
The color gradation and / or the resolution are gradually reduced to perform the highest quality printing that can be automatically printed. In the third embodiment, it is assumed that the printer driver has a plurality of dither patterns. These dither patterns can provide, for example, a very high-quality image as a print result, but they are difficult to compress (bitmap data size becomes large). Prepare a plurality of characteristic dither patterns such as one that is extremely effective (bitmap data becomes small) and one that is in between.

When the automatic high quality mode is selected and printing is executed, the bit map is expanded using the highest quality dither pattern at first. If the size of the generated bitmap data exceeds the printable bitmap data size, change to another dither pattern and expand the bitmap again.

According to the present embodiment, the dither pattern to be used is sequentially changed and bitmap expansion (rendering) is performed without changing the color gradation / resolution designated by the user, and the highest printable image quality is obtained. Has the effect of enabling automatic printing.

[0074]

[Other Embodiments] As described above, an object of the present invention is to provide a storage medium (or recording medium) recording a program code of software for realizing the functions of the above-described embodiments.
It is also achieved by supplying to the system or device, and the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Also,
By executing the program code read by the computer, not only the functions of the above-described embodiment are realized, but also the operating system (O) operating on the computer based on the instruction of the program code.
It goes without saying that S) and the like perform a part or all of the actual processing and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion card inserted in the computer or the function expansion unit connected to the computer, based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs some or all of the actual processing,
It goes without saying that the processing includes the case where the functions of the above-described embodiments are realized.

When the present invention is applied to the above storage medium, the storage medium stores the program code corresponding to the flowcharts of FIGS. 4 and 5 described above.

[0077]

As described above, according to the present invention,
It is possible to provide a host-based printing system that can automatically determine an optimal bitmap expansion condition such as an optimal number of color gradations and a control method thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color laser beam printer to which the present invention can be applied.

FIG. 2 is a block configuration diagram of a host-based color printing system according to the embodiment of the present invention.

FIG. 3 is a functional block diagram showing a processing configuration of a printing function of the printing system according to the embodiment of the present invention.

FIG. 4 is a flowchart showing an initialization process in the automatic color gradation control process according to the first embodiment.

FIG. 5 is a flowchart showing main processing in automatic color gradation control processing according to the first embodiment.

FIG. 6 is a diagram showing an example of a table that defines an order in which color gradation / resolution is reduced in the second embodiment.

Claims (16)

[Claims] 1. A host-based printing system, comprising: a printer; and a host computer connected to the printer, wherein the host computer generates bitmap data of print data and transfers the bitmap data to the printer. A bitmap expansion means for expanding the print data into a bitmap with a predetermined number of gradations and a resolution; and a determination means for determining whether or not the bitmap data expanded by the bitmap expansion means can be transferred to the printer. When the determination unit determines that the transfer to the printer is impossible, the bitmap development unit displays the gradation number and / or the gradation number obtained by subtracting a predetermined number from the current gradation number and / or resolution.
Alternatively, a host-based printing system comprising: a control unit that performs bitmap expansion at a resolution. 2. The determining means calculates the maximum size of bitmap data printable by the printer, the size of bitmap data expanded by the bitmap expanding means, and the calculating means. Comparing means for comparing the maximum size with the maximum size, and determining that transfer to the printer is impossible when the size of the bitmap data expanded by the bitmap expanding means exceeds the maximum size. The host-based printing system according to claim 1. 3. The capacity of a video output buffer in the printer for temporarily storing the bitmap data transferred from the host computer,
The host-based printing system according to claim 2, wherein the maximum size is calculated based on a data transfer rate between the printer and the host computer. 4. The host computer, an acquisition unit that acquires the capacity of the video output buffer, a measurement unit that measures the data transfer rate, a capacity of the video output buffer acquired by the acquisition unit, and The host-based printing system according to claim 3, further comprising: a storage unit that stores the data transfer rate measured by the measuring unit. 5. The measuring means comprises means for transferring dummy data of a predetermined size to the printer and measuring a time required for the transfer, and calculating the data transfer rate based on the time required. The host-based printing system of claim 4, wherein the host-based printing system is a printing system. 6. A method of controlling a host-based printing system, comprising: a printer; and a host computer connected to the printer, wherein the host computer generates bitmap data of print data and transfers the bitmap data to the printer. The host computer determines whether or not to transfer the print data to the printer by a bitmap expansion step of expanding the print data into a bitmap with a predetermined number of gradations and a predetermined resolution. If it is determined that the transfer to the printer is impossible in the determination step and the determination step, the process returns to the bitmap expansion step and the number of gradations obtained by subtracting a predetermined number from the current number of gradations and / or resolution And / or a control step for expanding the bitmap at the resolution, Control method for a host based printing system according to claim Rukoto. 7. The determining step includes a calculating step of calculating a maximum size of bitmap data printable by the printer, a size of bitmap data expanded in the bitmap expanding step, and a calculating step in the calculating step. And a comparison step of comparing the maximum size of the bitmap data with the maximum size of the bitmap data, and determining that transfer to the printer is impossible when the size of the bitmap data expanded in the bitmap expansion step exceeds the maximum size. The host-based printing system control method according to claim 6, wherein 8. The calculating step is based on a capacity of a video output buffer in the printer for temporarily storing bitmap data transferred from the host computer, and a data transfer rate between the printer and the host computer. The method of controlling a host-based printing system according to claim 7, wherein the maximum size is calculated. 9. The method according to claim 8, further comprising: an acquisition step of acquiring the capacity of the video output buffer, and a measurement step of measuring the data transfer amount, prior to the calculation step. Control method for host-based printing system. 10. The measuring step has a step of transferring dummy data of a predetermined size to the printer and measuring a time required for the transfer, and calculating the data transfer rate based on the time required. The method of controlling a host-based printing system according to claim 9. 11. A computer-executable program that causes a computer device that executes the program to function as a host computer in the host-based printing system according to claim 1. Characteristic program. 12. A storage medium storing the program according to claim 11. 13. A host-based printing system, comprising: a printer; and a host computer connected to the printer, wherein the host computer generates bitmap data of print data and transfers the bitmap data to the printer. A storage unit that stores a plurality of types of dither patterns, a bitmap expansion unit that expands the print data into a bitmap using a predetermined dither pattern of the plurality of types of dither patterns, and a bitmap expansion unit. When the determination unit determines that transfer of the expanded bitmap data to the printer is not possible, and when the determination unit determines that transfer to the printer is impossible, a different dither pattern is applied to the bitmap expansion unit. Control means for performing bitmap expansion using And a host-based printing system. 14. A method of controlling a host-based printing system, comprising: a printer; and a host computer connected to the printer, the host computer generating bitmap data of print data and transferring the bitmap data to the printer. The host computer develops the print data into a bitmap using a predetermined dither pattern of a plurality of types of dither patterns stored in a memory, a bitmap expanding step, and a bitmap expanded in the bitmap expanding step. A determination step of determining whether or not the data can be transferred to the printer, and when the determination step determines that the transfer to the printer is not possible, the flow returns to the bitmap expansion step and bitmap expansion is performed using a different dither pattern. Has a control step that causes Control method for a host-based printing system, characterized in that. 15. A program executable by a computer device, which causes the computer device executing the program to function as a host computer in the host-based printing system according to claim 13. 16. A storage medium storing the program according to claim 15.