JP3862363B2 - Information output system and information output method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information output system and an information output method including an information processing apparatus that supplies output information and a printing apparatus that prints out output information supplied from the information processing apparatus.
[0002]
[Prior art]
As a recent printing device, it prints and records data used in multimedia processing such as CAD (Computer Aided Design), CG (Computer Graphics), Design, DTP (Desktop Publishing) in business, etc. with high definition. The printer has been commercialized.
[0003]
As such a printer, a printing apparatus having a printer control function called a printer control language (PDL (Printer Description Language)) (page description language) or a printer control command sent from a host computer receives and analyzes the PDL code. The PDL printer that renders the stored intermediate language at high speed with hardware or software (rasterization) and the functions on the printer side are reduced, and the host computer side rasterizes it into a form that can be output by the printer. Some image printers are designed to reduce costs.
[0004]
This printer is often controlled from the host computer side by a printer driver provided in the host computer or software called a print spooler or a print processor.
[0005]
Some image printers are of the bubble jet printer type that compresses image data and sends the image data in synchronization with the paper discharge speed from the host computer. Since the bubble jet printer engine can stop the printing process in units of bands, printing can be performed even if the compression rate is poor if it has a minimum of one band of memory.
[0006]
[Problems to be solved by the invention]
However, when trying to realize an image printer with a laser beam printer engine, there is a feature that “the LBP engine cannot be stopped in the middle of the printing process”. The image data storage memory had to be retained. In other words, in the case of a 600 DPI, A4 monochrome printer, a 4 Mbyte, YMCK output color printer requires a 16 Mbyte data storage memory, and the cost of the apparatus cannot be avoided.
[0007]
The present invention has been made for the purpose of solving the above-described problems. For example, in a printer engine that cannot stop printing processing, it is intended to enable high-definition printing without having a memory for one page. To do.
[0008]
[Means for Solving the Problems]
For example, the following configuration is provided as a means for achieving the above-described object.
[0009]
  That is, an information output system including an information processing apparatus that supplies output information and a printing apparatus that prints and outputs the output information supplied from the information processing apparatus, and a drawing function that draws an output image on the information processing apparatus And a printer driver function that controls an interface with the printing apparatus, wherein the printer driver function binarizes the intermediate data drawn by the drawing function by a dither process for each band processed by the printing apparatus Expansion means for expanding into a data format, a data transfer rate obtained from the connection form of the printing apparatus and its own apparatus, a bandwidth of output information in band units developed by the expansion means, and one band of the printing apparatus To obtain the minimum compression ratio in time for the paper discharge speed of the printing device when the data is transferred at the data transfer rate A first compression means for performing a lossless compression process on the output information of all bands obtained by the expansion means, and a compression ratio among the output information of each band subjected to the lossless compression process by the first compression means. Determining means for determining whether or not there is a band for which the minimum compression ratio calculated by the means is not obtained; and when the determination means determines that there is a band for which the minimum compression ratio cannot be obtained, binarization is performed by dither processing. A rearrangement unit that rearranges dots in units of dither cycles and performs a lossless compression process by the first compression unit, and a determination unit that performs rearrangement by the rearrangement unit after the rearrangement by the rearrangement unit. It is determined that there is a band where the minimum compression rate cannot be obtained.And when the intermediate data included in the determined band includes high-resolution multivalued image data.Converting the high-resolution multi-value image data of the intermediate data included in the determined band into low-resolution multi-value image data, and developing all bands related to the multi-value image data by the development means Image data conversion means for performing processing;After the reordering by the reordering means, the determining means determines that there is a band for which the minimum compression rate cannot be obtained, and high-resolution multivalued image data exists in the intermediate data included in the determined band If notWhen there is a second compression unit that performs irreversible compression processing on the output information of all bands, and after the irreversible compression processing by the second compression unit, there is a band for which the minimum compression rate cannot be obtained, the irreversible compression processing Compression ratio changing means for increasing the compression ratio and executing lossy compression processing by the second compression means, and enabling the printing apparatus to output a high-definition image without having a page memory for one page. It is characterized by that.
[0010]
  Further, the printing apparatus includes a color print processing unit, and the expansion unit in the printer driver function expands the intermediate data into an image data format binarized by dither processing for each color processed by the printing apparatus, The second compression means uses a color dither matrix table for color image data and a monochrome dither matrix table for monochrome image data, and the dot arrangement is different between the color dither matrix table and the monochrome dither matrix table. It is characterized by that.
[0011]
  Alternatively, an information output method in an information output system including an information processing device that supplies output information and a printing device that prints out output information supplied from the information processing device, the output image being output to the information processing device A drawing function for drawing, and a printer driver function for controlling an interface with the printing apparatus. The printer driver function performs dither processing for each band in which intermediate data drawn by the drawing function is processed by the printing apparatus. A developing step of developing into a quantified image data format; a data transfer rate obtained from a connection form between the printing apparatus and the self apparatus; a bandwidth of output information in band units developed in the developing process; and the printing apparatus From the discharge speed of one band of the printer, it is the best time to meet the discharge speed of the printing apparatus when transferring at the data transfer rate. Among the output information of each band subjected to the lossless compression processing in the first compression step, the calculation step for obtaining the compression ratio, the first compression step for performing the lossless compression processing on the output information of all the bands obtained in the expansion step A determination step for determining whether or not there is a band for which the compression rate is not obtained in the calculation step and a band for which the minimum compression rate is not obtained in the determination step. A rearrangement step for rearranging dots in units of dither cycles and performing a lossless compression process in the first compression step with respect to the scan line of the binarized image data, and after the rearrangement in the rearrangement step In the determination step, it is determined that there is a band for which the minimum compression rate cannot be obtained.And when the intermediate data included in the determined band includes high-resolution multivalued image data.Converting the high-resolution multi-value image data of the intermediate data included in the determined band into low-resolution multi-value image data, and developing all bands related to the multi-value image data in the development step An image data conversion process for processing,After the rearrangement in the rearrangement step, it is determined in the determination step that there is a band for which the minimum compression rate cannot be obtained, and high-resolution multivalued image data exists in the intermediate data included in the determined band If notWhen there is a band in which the minimum compression rate cannot be obtained after the second compression step for performing lossy compression processing on the output information of all bands and the lossy compression processing in the second compression step, the lossy compression processing is performed. The compression ratio is increased, and the compression ratio changing step for executing the lossy compression process in the second compression step is executed, so that the printing apparatus can output a high-definition image without having a page memory for one page. It is characterized by doing.
[0012]
  Further, the printing apparatus includes a color print processing unit, and in the developing step in the printer driver function, the intermediate data is developed into an image data format binarized by dither processing for each color processed by the printing apparatus, In the second compression step, a color dither matrix table for color image data and a monochrome dither matrix table for monochrome image data are used, and the dot arrangement is different between the color dither matrix table and the monochrome dither matrix table. It is characterized by that.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[0017]
<Outline of the main unit>
FIG. 1 is an external perspective view showing an outline of the configuration of an inkjet printer IJRA that can be used as a printing apparatus of the present invention. In FIG. 1, the carriage HC engaged with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5011 and 5009 in conjunction with the forward / reverse rotation of the drive motor 5013 has a pin (not shown). And is reciprocated in the directions of arrows a and b. An ink jet cartridge IJC is mounted on the carriage HC. Reference numeral 5002 denotes a paper pressing plate that presses the paper against the platen 5000 in the moving direction of the carriage. Reference numerals 5007 and 5008 denote photo-couplers, which are home position detection means for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the motor 5013 or the like. Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the recording head. Reference numeral 5015 denotes suction means that sucks the inside of the cap, and performs suction recovery of the recording head through an opening 5023 in the cap. Reference numeral 5017 denotes a cleaning blade, and reference numeral 5019 denotes a member that enables the blade to move in the front-rear direction, and these are supported by a main body support plate 5018. Needless to say, the blade is not in this form, and a known cleaning blade can be applied to this example. Reference numeral 5012 denotes a lever for starting suction for suction recovery, which moves in accordance with the movement of the cam 5020 engaged with the carriage, and the driving force from the driving motor is controlled by a known transmission means such as clutch switching. Is done.
[0018]
These capping, cleaning, and suction recovery are configured so that desired processing can be performed at their corresponding positions by the action of the lead screw 5005 when the carriage comes to the home position side region. Any of these can be applied to this example as long as the above operation is performed.
[0019]
<Description of control configuration>
Next, a control configuration for executing the recording control of the above-described apparatus will be described.
FIG. 2 is a block diagram showing the configuration of the control circuit of the inkjet printer IJRA. In the figure, showing a control circuit, 1700 is an interface for inputting a recording signal, 1701 is an MPU, 1702 is a program ROM for storing a control program executed by the MPU 1701, and 1703 is various data (the recording signal and the recording supplied to the head). This is a dynamic RAM that stores data and the like. Reference numeral 1704 denotes a gate array that controls supply of print data to the print head 1708, and also controls data transfer among the interface 1700, MPU 1701, and RAM 1703. Reference numeral 1710 denotes a carrier motor for conveying the recording head 1708, and 1709 denotes a conveyance motor for conveying the recording paper. Reference numeral 1705 denotes a head driver for driving the head, and reference numerals 1706 and 1707 denote motor drivers for driving the transport motor 1709 and the carrier motor 1710, respectively.
[0020]
The operation of the control configuration will be described. When a recording signal enters the interface 1700, the recording signal is converted into recording data for printing between the gate array 1704 and the MPU 1701. The motor drivers 1706 and 1707 are driven, and the recording head is driven in accordance with the recording data sent to the head driver 1705 to perform printing.
The present invention includes means (for example, an electrothermal converter or a laser beam) that generates thermal energy as energy used for ejecting ink, particularly in an ink jet recording system, and the state of ink by the thermal energy. A printing apparatus that causes a change has been described, but according to such a system, higher recording density and higher definition can be achieved.
[0021]
As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to recording information and applying a rapid temperature rise exceeding film boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface of the liquid, and as a result, bubbles in the liquid (ink) corresponding to the drive signal on a one-to-one basis can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. When the drive signal is pulse-shaped, the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve the discharge of liquid (ink) with particularly excellent responsiveness.
[0022]
As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.
[0023]
As the configuration of the recording head, in addition to the combination configuration (straight liquid flow path or right-angle liquid flow path) of the discharge port, the liquid path, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the heat acting surface The configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which is disposed in a bending region, are also included in the present invention. In addition, Japanese Patent Application Laid-Open No. 59-123670, which discloses a configuration in which a common slot is used as a discharge portion of an electrothermal transducer, or an opening that absorbs a pressure wave of thermal energy is discharged to a plurality of electrothermal transducers. A configuration based on Japanese Patent Laid-Open No. 59-138461 disclosing a configuration corresponding to each part may be adopted.
[0024]
Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is satisfied by a combination of a plurality of recording heads as disclosed in the above specification. Either a configuration or a configuration as a single recording head formed integrally may be used.
[0025]
In addition, the ink is integrated into the replaceable chip type recording head or the recording head itself, which can be electrically connected to the apparatus main body and supplied with ink from the apparatus main body by being attached to the apparatus main body. A cartridge type recording head provided with a tank may be used.
[0026]
In addition, it is preferable to add a recovery means for the recording head, a preliminary auxiliary means, etc. provided as a configuration of the recording apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, capping means, cleaning means, pressurizing or suction means for the recording head, preheating means using a heating element different from this, or a combination thereof, or recording is used. Performing a preliminary discharge mode for performing another discharge is also effective for performing stable recording.
[0027]
Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head may be integrated or may be a combination of a plurality of colors. An apparatus having at least one of full colors can also be provided.
[0028]
In the embodiment of the present invention described above, the ink is described as a liquid. However, even if the ink is solidified at room temperature or lower, the ink is softened or liquefied at room temperature. Or, in the ink jet system, the ink itself is generally controlled by adjusting the temperature within a range of 30 ° C. or higher and 70 ° C. or lower so that the viscosity of the ink is in a stable discharge range. Any ink may be used as long as the recording signal is applied.
[0029]
In addition, it is solidified in an untreated state in order to actively prevent the temperature rise by thermal energy from being used as the energy for changing the state of the ink from the solid state to the liquid state, or to prevent the ink from evaporating. Ink that is liquefied by heating may be used. In any case, by applying heat energy according to a recording signal of thermal energy, the ink is liquefied and liquid ink is ejected, or when it reaches the recording medium, it already starts to solidify. The present invention can also be applied to the case where ink having a property of being liquefied for the first time is used. In such a case, the ink is held as a liquid or solid in a porous sheet recess or through-hole as described in JP-A-54-56847 or JP-A-60-71260, It is good also as a form which opposes with respect to an electrothermal converter. In the present invention, the most effective one for each of the above-described inks is to execute the above-described film boiling method.
[0030]
In addition, as a form of the recording apparatus according to the present invention, a copying apparatus combined with a reader or the like, and a transmission / reception function are provided as an image output terminal of an information processing apparatus such as a computer or the like. It may take the form of a facsimile machine.
[0031]
<Overall configuration of print output system>
FIG. 3 is a block diagram showing the overall configuration of the print output system according to the embodiment of the present invention.
[0032]
In FIG. 1, 101 is a host computer, 103 is a printer controller, and 110 is a printer engine. In principle, data transfer between the host computer 101 and the printer controller 103 is performed by DMA transfer. Output information is supplied from the printer controller 103 to the printer engine 110 in the form of a video signal.
[0033]
The printer engine 110 is a printer that prints out a video signal sent from the printer controller 102, and may be a laser beam printer (LBP) using electrophotography or the above-described inkjet printer, and may be a color printer or a monochrome printer. Good.
[0034]
The host computer 101 can start a drawing application program (not shown), and data created using the drawing application program is converted into a data format that can be received by the printer by an image driver provided in the host computer 101.
[0035]
The converted data is sent to the printer controller 103 by DMA transfer via a connection cable indicated by the host computers 101 to 102. Data input from the host computer 101 to the printer controller 103 by DMA transfer is stored in the input buffer 104 (RAM).
[0036]
The data stored in the input buffer 104 is processed by a transfer data analysis program in the program ROM 105. The program ROM 105 is, for example, a memory that stores a CPU control program including a processing procedure (control program) shown in FIG. 13 to be described later. The CPU 106 reads data according to the control program and executes each process.
[0037]
When the data is stored in the input buffer 104, the CPU 106 sets parameters such as the drawing position of the image data in the image hard renderer 107.
The image hard renderer 107 converts the image data in the input buffer 104 into the output format of the printer engine 110 in accordance with the set parameters, and renders it in the band memory 108.
[0038]
In the present embodiment, at least two band memories (page width × band height of about 128) are provided, and the shipping state, the image development state, and the character drawing state are combined by a chasing process. The information of the band for which the composition process has been completed is immediately sent to the printer engine 110 via a printer interface (video interface) 109 which is an interface with the printer engine 110.
[0039]
The printer interface 109 performs command transmission to the printer engine 110 and status reception from the printer engine 110 with the printer engine 110, for example, the above-described inkjet printer or laser beam printer (LBP) with the band memory 108. .
[0040]
The connection cable 102 may be a direct connection between a host machine such as a Centronics cable and a printer, or may be via a network. The CPU 105 is an arithmetic device that controls internal processing of the printer controller 102.
[0041]
In the program ROM 105 of this embodiment, for example, various programs shown in FIG. 4 are stored.
[0042]
That is, a print control program 105-1 that controls an interface with the printer engine 110, a host interface program 105-2 that controls an interface with the host computer 101, a compression control program 105-3 that controls compression of output information, which will be described later, and a printer engine The output of the printer engine 110 when the data transfer rate with the host computer 101 is calculated from the specifications of 110 and the output information for each band developed based on the control of the data development control program described later is transferred at the calculated transfer rate. A data transfer control program 105-4 for obtaining a minimum compression rate in time for the paper speed and a printer engine 110 that processes intermediate data of output information created by the drawing application program of the host computer 101. It contains the data expansion control program 105-5 to expand the image data format of the unit.
[0043]
A high-definition image can be output without having a page memory for one page.
(Basic processing)
A basic process for print information in the present embodiment having the above-described configuration will be described below with reference to FIG. In the following description, a case where the printer engine 110 is a monochrome printer will be described as an example.
[0044]
FIG. 5 is an explanatory diagram showing an outline from when the printer driver 200 in the host computer 101 creates data in which characters and graphics are mixed and outputs the data to the printer controller 103.
[0045]
Reference numeral 202 denotes a schematic diagram of an output result displayed on a display of a result drawn by the drawing application. The horizontal stripes indicate band boundaries that are units for processing on the printer side.
[0046]
When receiving a print command by inputting an instruction from a keyboard, mouse, or the like, the application software of the host computer 101 generates a print command using the function of the OS and the function of the printer driver 200. Recent personal computer OS (for example, Windows, MacOS, etc.). In general, a print command is generated according to the capability of the printer.
[0047]
When the printer driver 200 sets “a printer that can handle only band-unit image data” to the OS, the OS expands characters and graphics into band-unit image data as indicated by 203. The printer driver 200 adds binarization processing in accordance with printer characteristics to the data as indicated by 204.
[0048]
Here, for example, in order to increase the transfer rate, Loss Less compression processing without data loss is added to the data to align all bands of one page (205).
[0049]
When all the bands are ready, the data is transferred to the input buffer 104 of the printer controller 103. When data is stored in the input buffer 104 of the printer controller 103, the output information received using the image hard renderer 107 is immediately decompressed and stored in the two band memories.
[0050]
At the same time, the printer engine 110 is activated and waits for a data request signal from the printer engine 110. When the data request signal from the printer engine 110 arrives, the prepared image data is transmitted to the band memory 108, and the expansion of the next image data is developed in time for the discharge speed in the vacant band.
[0051]
In FIG. 5, when output information is stored in the input buffer 104 from the host side printer driver 200, the image hard renderer 107 stores the received data in the band memory 108 while performing decompression processing, and then outputs it to the printer engine 110. .
(LossLess compression method)
The conditions for the compression method in the printer driver 200 are that the compression rate is high and the decompression process on the printer side is fast. In order to achieve a compression method that satisfies these conditions, in this embodiment, the image data transferred to the printer side is binary image data by dither processing, and the Loss Less compression method (byte run length compression method, pack Bets that use the BitBit compression method, etc.
[0052]
This compression method is a method of compressing data by setting a consecutive number and a value when the values of adjacent bytes are continuous. Since the structure is simple, both encoding and decoding can be performed at high speed even with software.
[0053]
In the byte run length compression method, data is described as a unit of a total of 2 bytes including a control part (1 byte) for designating the number of appearances and a data part (1 byte) for describing the appearing data. In this method, the number of consecutive appearances can be specified up to 256, and the value of “appearance count−1” is described.
[0054]
In the Packbits compression method, data is described in units of a total of 2 bytes including a control part (1 byte) for specifying the number of appearances and a data part (1 byte) for describing the appearing data. Thus, the number of appearances can be specified up to 128, and a value of “(number of appearances−1) × (−1)” is described. Non-repeated data (data that appears only once) is a method of describing the value of “(appearance count−1)” as the number of bytes of non-repeated data in the control unit.
[0055]
Further, in this embodiment, a dither method in units of byte width is used as a binarization method in order to increase the compression rate of the byte run length and pack bits compression method.
[0056]
The operation when the constant density (55) is binarized using a dither method in byte width units as a binarization method in the present embodiment will be described with reference to FIG.
[0057]
The dither method is a method in which an 8 × 8 dither matrix table as shown in the upper part of FIG. 6 is stretched over the entire page, and when the gradation value of the corresponding pixel is larger, the pixel is turned ON.
[0058]
When an image of density 55 on one surface is binarized with a dither matrix (300), as shown in the lower portion 301, the same value becomes continuous data in units of scan lines.
[0059]
That is, for example, data in which a wide area created with DTP software and Draw software is painted with the same color can obtain a high compression rate. Conversely, data in which irregular density patterns appear at a high resolution cannot be increased even if dither processing is applied, but rather becomes low.
[0060]
However, if the compression rate of the data to be transferred to the compressed printer is low and the required transfer rate cannot be obtained, processing is performed with an input buffer that does not contain one page (an input buffer that has a capacity of one page or less). Is impossible.
[0061]
The data transfer rate is physically determined by the connected printer (by the connection cable 102), and can be obtained if the connection form between the host computer and the printer is understood. Also, the bandwidth can be obtained from the output page format. Therefore, in the printer driver 200 of the present embodiment, the minimum compression rate is obtained from the data transfer rate (bytes / second), the number of bandwidth bytes (bytes), and the paper discharge speed (l line / second).
[0062]
Minimum compression rate (%)
= ((Data transfer rate) / (bandwidth byte number × discharge speed)) × 100
If the minimum compression rate obtained by the above formula is not obtained by LossLess compression such as run length compression method or pack bits compression method, the compression rate is raised by the following countermeasure.
(First countermeasure when the compression ratio exceeds the specified value)
First, referring to FIG. 7, a first countermeasure when the compression rate in the present embodiment exceeds a specified value will be described with reference to FIG.
[0063]
The LossLess compression process is performed for each band in the same manner as the normal process shown in FIG. In FIG. 7, the same processes as those shown in FIG.
[0064]
When receiving the print command, the application software of the host computer 101 generates a print command using the function of the OS and the function of the printer driver 200. The printer driver 200 adds binarization processing in accordance with printer characteristics to the data as indicated by 204.
[0065]
Here, in order to increase the transfer rate, Loss Less compression processing is added to align all the bands of one page (205). As a result, if there is a band in which the target compression rate cannot be obtained, the Loss Less filter (interleave processing) is applied to the original data 204 to generate data indicated by 406. Thereafter, Loss Less compression is applied again to obtain data indicated by 407.
[0066]
When all the band data is ready, the data is transferred to the input buffer 104 of the printer controller 103. Subsequent operations are the same as those shown in FIG.
[0067]
Details of the above-described LossLess filter (interleaving process) will be described below with reference to FIG.
[0068]
As described above, the image data 500 binarized by 8 × 8 dither processing as indicated by 300 in FIG. 6 is similar in 8-dot period as indicated by 501 when viewed in units of one scan line. It has the characteristic that dot patterns appear continuously. For this reason, the compression rate is high even if the byte run length compression process is applied as it is, but the compression rate decreases if there is a different byte even at one dot.
[0069]
Therefore, in the interleave filter processing in this embodiment, as shown by 502, the scan lines are rearranged by collecting dots in units of dither cycles. As described above, since data having a periodicity is collected to reconstruct data, the data indicated by 502 is likely to have a higher compression ratio of run length compression and packbits compression than the data indicated by 501. Therefore, by performing the above processing, it is possible to solve the situation where the compression rate of the data transferred to the compressed printer is low and the necessary transfer rate cannot be obtained.
(Second countermeasure when the compression ratio exceeds the specified value)
In order to maximize the performance of the printer and output it with high definition, the printer driver decompresses the image data at high resolution and transfers it with the LossLess compression method without loss of data even when compressing it. However, it may be possible that the compression rate does not increase. In the present embodiment, in order to deal with the above situation, the following method is taken when a sufficient compression rate cannot be obtained or there is a possibility that the above treatment method cannot be obtained.
[0070]
Hereinafter, with reference to FIG. 9, a second countermeasure when the compression rate in the present embodiment exceeds a specified value will be described. 9, the same processes as those shown in FIGS. 5 and 7 described above are denoted by the same reference numerals, and detailed description thereof is omitted.
[0071]
As a result of applying the LossLess compression process in units of bands as in the normal process (205), if there is a band for which the above-described minimum compression rate cannot be obtained, the following control is performed.
[0072]
When high resolution image data is included in a band where the minimum compression rate cannot be obtained, there is a high possibility that the cause of the compression rate not being increased is the image data. For this reason, in this coping method, redrawing processing is performed for all bands including high-resolution image data. At this time, the image data is drawn by reducing entropy by Lossy filtering processing, and new development drawing data indicated by reference numeral 606 is generated. Then, binarization processing (dithering) is performed on this data to obtain data indicated by 607. Then, Loss Less compression is applied again to the data 607 to obtain compression information 608.
[0073]
However, in the above processing, if there are characters, graphics, etc. other than the high-resolution image in the re-expansion processing, the drawing processing is performed at high resolution for these.
(Development processing at low resolution for multi-valued image data)
Entropy is high for complex images with high resolution. Accordingly, refer to FIG. 10 for a method of reducing the entropy of the high-resolution, multi-valued image in the re-development processing in the second countermeasure shown in FIG. 9 in the present embodiment in the case of such multi-valued image data. This will be described below.
[0074]
High resolution and complex images have high entropy. Therefore, even if the multi-value source image 700 is binarized by dither processing, the image data has a low compression ratio because the correlation between adjacent bytes is low as indicated by reference numeral 701.
[0075]
For this reason, in this embodiment, the low-resolution multi-level source image data 700 shown in 702 is obtained by a simple thinning method that takes an average value in units of 2 × 2 pixels in the vertical and horizontal directions, or takes one of four pixels. Value image data can be obtained. When binarization processing is added to the data shown in 702, the image data shown in 703 has a smaller entropy than the data shown in 701, and the compression rate is improved.
(Development processing at low resolution for binary image data)
FIG. 9 is a diagram illustrating a method of reducing the entropy of a high-resolution binary image in the re-development process in the second countermeasure shown in FIG. 9 in the present embodiment when the source image data handled by the application in the present embodiment is a binary image. 11 will be described below.
[0076]
When the high-resolution binary image indicated by 800 in FIG. 11 is expanded as shown by 801 by, for example, equal magnification or scaling, as shown by 801, image data with a low compression rate is obtained because the correlation between adjacent bytes is thin. Become.
[0077]
Therefore, in the present embodiment, the number of ON pixels is counted in units of 2 × 2 pixels in the vertical and horizontal directions of the binary source image data 800, and the 2 × 2 pixel values are converted according to a lookup table as shown in 802. Thus, data 803 is obtained. Since the data indicated by 803 obtained in this way has regularity of data compared to the source data indicated by 800, the subsequent compression rate can be improved.
(Third countermeasure when the compression ratio exceeds the specified value)
If there is a band for which the compression ratio to be obtained cannot be obtained even if the first countermeasure or the second countermeasure described above is performed, the third countermeasure shown below is performed. In the third countermeasure, the compression rate is improved by applying Lossy filtering processing to all bands. In the third countermeasure, if Lossy filtering processing is applied only to a specific band, the joint with other bands is conspicuous, and it is necessary to apply Lossy filtering processing to all bands.
[0078]
Hereinafter, with reference to FIG. 12, a third countermeasure when the compression rate in the present embodiment exceeds a specified value will be described. In FIG. 12, the same processes as those shown in FIGS. 5, 7, and 9 described above are denoted by the same reference numerals, and detailed description thereof is omitted.
[0079]
As a result of applying the LossLess compression process in units of bands as in the normal process (205), if there is a band for which the above-described minimum compression rate cannot be obtained, the following control is performed.
[0080]
As a result of compression by LossLess compression (205) If the compression ratio is less than the specified value, the decompression process is performed to obtain data indicated by 906, and the binary shown in FIG. 11 of the second countermeasure for the entire band Image Lossy filtering processing is performed to obtain data 907. If the Loss Less compression process is performed on the data 907 and the compression rate is within the specified value, the same filtering process is performed on all the bands developed so far.
[0081]
When all the band data (908) is obtained, the data is transferred to the input buffer 104 of the printer controller 103. Subsequent operations are the same as those shown in FIG.
(Description of data compression control in this embodiment)
An example of data compression control in the present embodiment in which the above first to third countermeasures are combined will be described with reference to the flowchart of FIG.
[0082]
First, in step S1, the host-side printer driver 200 performs rendering (rendering processing) of an object to be printed at high resolution in band units. Here, the binarization process is performed. In the subsequent step S2, Loss Less compression processing is added in band units. This process corresponds to the data compression of the basic process shown in FIG.
[0083]
Subsequently, in step S3, it is checked whether or not there is a band for which the minimum compression rate in time for the paper discharge speed of the printer when the data is transferred at the data transfer rate to the printer at the time of data transfer between the printer and the self apparatus. If there is no band whose compression rate exceeds the specified value, the process proceeds to step S4, and all band data of the compressed data is transferred to the reception buffer 104 of the printer controller 103. Then, the process ends.
[0084]
On the other hand, if there is a band that cannot obtain the minimum compression rate in time for the discharge speed of the printer in step S3, the process proceeds to step S5, and the first band shown in FIG. Interleave processing in the target method is performed, and then Loss Less compression is applied again to obtain compressed information.
[0085]
Subsequently, in step S6, it is checked whether or not there is a band for which the minimum compression rate in time for the paper discharge speed of the printer when the data is transferred at the data transfer rate to the printer at the time of data transfer between the printer and the apparatus itself. If there is no band whose compression rate exceeds the specified value, the process proceeds to step S4, and all band data of the compressed data is transferred to the reception buffer 104 of the printer controller 103. Then, the process ends.
[0086]
On the other hand, if there is a band that cannot obtain the minimum compression rate in time for the discharge speed of the printer in step S6, the process proceeds to step S7, and it is determined whether or not there is high-resolution image intermediate data in the band that cannot obtain the compression rate. Investigate. If there is high resolution image intermediate data in a band where the compression rate cannot be obtained, the process proceeds to step S8, and when the high resolution image intermediate data shown in FIG. The rendering process is performed after conversion (up to the binarization process), and the development process at a low resolution in the case of multi-value image data is performed. Then, the process returns to step S2, and Loss Less compression is applied again to obtain compression information.
[0087]
On the other hand, if there is no high-resolution image intermediate data in the band where the compression rate cannot be obtained in step S6, the process proceeds to step S10, and Lossy compression processing is performed on all bands in the third countermeasure shown in FIG. Process to add. In step S11, it is checked whether or not there is a band for which the minimum compression rate is not obtained in time for the discharge speed of the printer when data is transferred at the data transfer rate to the printer at the time of data transfer between the printer and its own apparatus. If there is no band whose compression rate exceeds the specified value, the process proceeds to step S4, and all band data of the compressed data is transferred to the reception buffer 104 of the printer controller 103. Then, the process ends.
[0088]
On the other hand, if there is a band for which the minimum compression rate in time for the discharge speed of the printer cannot be obtained in step S11, the process proceeds to step S12, and the compression rate of the Lossy compression rate is increased. Then, the process returns to step S10 again, and processing for adding Lossy compression processing to all bands is performed.
[0089]
By performing the above processing, the degradation of print output image quality to the printer is minimized, and when transferring data between the printer and its own device, all bands are transferred at the data transfer rate to the printer. Output data can be transferred in time for the discharge speed of the printer, and the printer can output a high-definition image without having a page memory for one page.
[0090]
In this case, the data transfer rate can be improved without degrading the image quality by applying the LossLess compression process in band units when compressing the image.
[0091]
Further, by performing the LossLess compression process after performing the LossLess filtering process on the band where the minimum compression rate cannot be obtained by the LossLess compression process, the data transfer rate can be improved without degrading the image quality.
[0092]
Furthermore, if Loss Less compression processing is applied in band units, if the minimum compression rate cannot be obtained, Lossy filtering processing is applied to intermediate data that causes the compression rate to decrease, and the processing speed is reduced by developing the image into an image. In addition, the compression rate can be improved.
[0093]
In addition, if the minimum compression rate cannot be obtained even after performing the band unit LossLess compression, the data amount can be reduced by reducing the resolution of all the bands, and the data transfer rate to the printer is surely applied to all the bands. The output data can be transferred in time for the discharge speed of the printer at the time of transfer, and the printer can output a high-definition image without having a page memory for one page. .
[0094]
In addition, high-definition output can be achieved by combining various processes such as Loss Less compression, Loss Less filtering processing for each band in the above description, and adding Lossy processing to an object with a poor compression rate, or performing Lossy processing on the entire page. Can be.
<Embodiment of the second aspect of the present invention>
The case where the printer is a monochrome printer has been described as an example. However, the present invention is not limited to the above example, and of course can be applied to, for example, a color printer. A second embodiment of the present invention in which the present invention is applied to a color printer will be described below. In the following description, the color printer will be described as an LBP color printer.
(Printer processing that can handle color image data)
FIG. 14 shows an example of a printer to which the second embodiment of the present invention according to the present invention is applied to a color printer. Hereinafter, one embodiment of an engine of a color laser beam printer applicable in the embodiment of the second invention will be described with reference to FIG.
[0095]
The color printer according to the second embodiment includes four color toners 1201 and transfers image data for one page to the transfer belt 1202 for each color. When the transfer belt 1202 rotates once, the color toner 1201 rotates 1/4 and the toner is switched.
[0096]
When the printing start signal is received and the printing process is started, the transfer belt 1202 rotates and the toner is switched in the order of yellow, magenta, cyan, and black. Further, the transfer from the transfer belt 1202 to the recording paper 1203 is performed, and the series of printing processes does not stop until the recording paper is transported and the paper discharge is completed (the printing processes are sequentially executed according to a predetermined time table). ).
[0097]
Processing in the embodiment of the second invention according to the present invention for realizing a memory-saving image printer using the above color printer engine will be described below with reference to FIG. FIG. 15 is a diagram for explaining the flow of processing of output information in the embodiment of the second invention.
[0098]
In order to realize a color image with the color LBP printer shown in FIG. 14 described above, the printer driver decomposes the image data into color image data for each color component as indicated by 1100 and separates each page for each color. Generate the minute data and save it temporarily. Then, image data may be continuously transferred to the printer in four pages for each color.
[0099]
However, in order to perform printing while performing data transfer, it is necessary to increase the transfer rate of each color data by applying a compression process above the minimum compression rate.
[0100]
Therefore, as in the case of the monochrome printer, Loss Less compression processing is performed for each color band, and compressed data for each color shown in 1101 is generated. This compressed data generation method is exactly the same as the compression process for one page in the monochrome printer described above, and the compression method in the first embodiment may be performed for four colors.
[0101]
If the compression rate required for the required transfer rate cannot be obtained even with the above compression method, a Lossy filter is applied. However, Lossy compression processing is performed not for each page but for each color. The Lossy compression method of the high-resolution binary image data is the same as that of the monochrome printer, but by using the dither matrix tables 1102 and 1103 shown in FIG. 15, the cyan, magenta, and yellow toners and the black toner are used. Reduce printing defects due to overlapping.
[0102]
As described above, even in a color printer, the degradation of the print output image quality to the printer is minimized, and when transferring data between the printer and its own device, all bands are transferred at the data transfer rate to the printer. The output data can be transferred in time for the discharge speed of the printer at that time, and the printer can output a high-definition image without having a page memory for one page.
[0103]
Also, when the printer engine is compatible with a color LBP printer and the printer is compatible with color data, drawing is performed by adding Loss Less compression processing and Loss Less filtering processing, and adding Lossy processing to the object that lowers the compression rate. Processing, processing for performing lossy processing on the entire page, and combining each processing in units of pigments, the highest resolution can be output.
[0104]
[Other Embodiments]
Note that the present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), or a device (for example, a copier, a facsimile device, etc.) including a single device. You may apply to.
[0105]
Another object of the present invention is to supply a storage medium storing software program codes for implementing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in the.
[0106]
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.
[0107]
As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
[0108]
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.
[0109]
Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0110]
When the present invention is applied to the above-mentioned storage medium, the program code corresponding to the flowchart described above is stored in the storage medium. For example, each module shown in the memory map example of FIG. This can be achieved by storing in
【The invention's effect】
As described above, according to the present invention, a printer having a small memory space can be used as an image printer.
[0111]
[Brief description of the drawings]
FIG. 1 is an external perspective view showing an outline of the configuration of an inkjet printer IJRA that can be used as a printing apparatus of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a control circuit of the inkjet printer IJRA.
FIG. 3 is a block diagram showing an overall configuration of a print output system according to an embodiment of the present invention.
4 is a diagram showing an example of a program stored in the program ROM shown in FIG. 3 in the present embodiment.
FIG. 5 is a diagram illustrating basic processing for print information according to the embodiment.
FIG. 6 is a diagram for explaining a binarization method when a constant density is binarized using a dither method in units of byte width in the present embodiment.
FIG. 7 is a diagram for explaining a first countermeasure when the compression ratio exceeds a specified value in the embodiment.
FIG. 8 is a diagram showing details of a LossLess filter (interleave processing) shown in FIG. 7;
FIG. 9 is a diagram for explaining a second countermeasure when the compression ratio exceeds a specified value in the present embodiment.
FIG. 10 is a diagram for explaining a method of reducing the entropy of a high-resolution, multi-value image in the second countermeasure.
FIG. 11 is a diagram for explaining a method of reducing entropy of a binary image in the second countermeasure.
FIG. 12 is a diagram for explaining a method of reducing entropy of a binary image in the third countermeasure when the compression rate in the present embodiment exceeds a specified value.
FIG. 13 is a flowchart showing an example of data compression control in the present embodiment when combining the first to third countermeasures when the compression rate in the present embodiment exceeds a specified value.
FIG. 14 is a diagram showing an example of a printer to which the embodiment of the second invention according to the present invention in which the present invention is applied is applied.
FIG. 15 is a diagram for explaining a flow of processing of output information in the embodiment of the second invention.

Claims (4)

An information output system including an information processing apparatus that supplies output information, and a printing apparatus that prints out output information supplied from the information processing apparatus,
A drawing function for drawing an output image on the information processing apparatus; and a printer driver function for managing an interface with the printing apparatus;
The printer driver function is
Developing means for developing intermediate data drawn by the drawing function into an image data format binarized by dither processing for each band processed by the printing apparatus;
From the data transfer rate obtained from the connection form of the printing apparatus and the self apparatus, the bandwidth of the output information in band units developed by the developing means, and the paper discharge speed for one band of the printing apparatus, the data transfer Calculating means for obtaining a minimum compression rate in time for the discharge speed of the printing apparatus when transferred at a rate;
First compression means for performing lossless compression processing on output information of all bands obtained by the expansion means;
A determination unit that determines whether there is a band in which the compression rate is not the minimum compression rate calculated by the calculation unit in the output information of each band that has been reversibly compressed by the first compression unit;
If it is determined by the determination means that there is a band for which the minimum compression rate cannot be obtained, the dots are rearranged in units of dither cycles for the scan lines of the image data binarized by the dither processing, Rearrangement means for performing lossless compression processing by the first compression means;
After the reordering by the reordering means, the determining means determines that there is a band for which the minimum compression rate cannot be obtained , and high-resolution multivalued image data exists in the intermediate data included in the determined band When converting, the high-resolution multivalued image data of the intermediate data included in the determined band is converted into low-resolution multivalued image data, and the development is performed for all bands related to the multivalued image data. Image data conversion means for performing development processing by means,
After the reordering by the reordering means, the determining means determines that there is a band for which the minimum compression rate cannot be obtained, and high-resolution multivalued image data exists in the intermediate data included in the determined band A second compression unit that performs irreversible compression processing on the output information of all bands,
If there is a band for which the minimum compression rate cannot be obtained after the lossy compression process by the second compression unit, the compression rate of the lossy compression process is increased and the lossy compression process by the second compression unit is executed. Compression rate changing means for causing
An information output system, wherein the printing apparatus is capable of outputting a high-definition image without having a page memory for one page. The printing apparatus includes a color print processing unit,
The expansion means in the printer driver function expands the intermediate data into an image data format binarized by dither processing for each color processed by the printing apparatus,
The second compression means uses a color dither matrix table for color image data and a monochrome dither matrix table for monochrome image data, and the dot arrangement is different between the color dither matrix table and the monochrome dither matrix table. The information output system according to claim 1. An information output method in an information output system comprising: an information processing apparatus that supplies output information; and a printing apparatus that prints output information supplied from the information processing apparatus,
A drawing function for drawing an output image on the information processing apparatus; and a printer driver function for managing an interface with the printing apparatus;
The printer driver function is
A developing step of developing intermediate data drawn by the drawing function into an image data format binarized by dither processing in band units processed by the printing device;
From the data transfer rate obtained from the connection form of the printing apparatus and the self apparatus, the bandwidth of the output information in band units developed in the development process, and the discharge speed for one band of the printing apparatus, the data transfer A calculation step for obtaining a minimum compression rate in time for the discharge speed of the printing apparatus when transferred at a rate;
A first compression step for performing lossless compression processing on output information of all bands obtained in the expansion step;
A determination step of determining whether there is a band in which the compression rate is not the minimum compression rate calculated in the calculation step among the output information of each band subjected to the lossless compression process in the first compression step;
When it is determined in the determination step that there is a band for which the minimum compression rate cannot be obtained, the dots are rearranged in units of dither periods for the scan lines of the image data binarized by the dither processing, A rearrangement step for performing a reversible compression process in the first compression step;
After the rearrangement in the rearrangement step, it is determined in the determination step that there is a band for which the minimum compression rate cannot be obtained , and high-resolution multivalued image data exists in the intermediate data included in the determined band When converting, the high-resolution multivalued image data of the intermediate data included in the determined band is converted into low-resolution multivalued image data, and the development is performed for all bands related to the multivalued image data. An image data conversion process for performing the development process in the process;
After the rearrangement in the rearrangement step, it is determined in the determination step that there is a band for which the minimum compression rate cannot be obtained, and high-resolution multivalued image data exists in the intermediate data included in the determined band If not, a second compression step of performing lossy compression processing on the output information of all bands;
If there is a band for which the minimum compression rate cannot be obtained after the lossy compression process in the second compression step, the compression rate of the lossy compression process is increased and the lossy compression process in the second compression step is executed. Executing the compression rate changing step
An information output method in an information output system, wherein the printing apparatus is capable of outputting a high-definition image without having a page memory for one page. The printing apparatus includes a color print processing unit,
In the expansion process in the printer driver function, the intermediate data is expanded into an image data format binarized by dither processing for each color processed by the printing apparatus,
In the second compression step, a color dither matrix table for color image data and a monochrome dither matrix table for monochrome image data are used, and the dot arrangement is different between the color dither matrix table and the monochrome dither matrix table. The information output method in the information output system of Claim 3 characterized by the above-mentioned.

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