JP2008142901A - Image formation controller and control method of image formation controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image formation controller which can efficiently suppress irregular colors for every paper conveyance width at the time of bidirectional recording that are caused by a difference of tones of color due to a difference in hitting sequence of ink color between forward scanning and rearward scanning in a color inkjet recorder. <P>SOLUTION: The image formation controller 801 inserts a second command descriptor between consecutive first command descriptors at a switching boundary of an image formation direction as a boundary between a raster in which an image forming engine carries out image formation by forward scanning and a raster in which the image forming engine carries out image formation by rearward scanning. Thus a profile switching control means is equipped which generates a third command descriptor. Also an image processing means is equipped which sequentially executes generation of image formation data, transfer of profile data for forward formation, or transfer of profile data for rearward formation on the basis of the third command descriptor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an image forming controller that is connected to an image forming engine to constitute an image forming system.

  In recent years, OA equipment such as personal computers (PCs) and copying machines has become widespread, and as a kind of image forming (recording) apparatus of these equipment, an apparatus that performs digital image recording by an ink jet method has been rapidly developed and popularized. ing.

  In particular, colorization has progressed with the enhancement of the functionality of OA equipment, and various color ink jet recording apparatuses have been developed accordingly.

  In general, an ink jet recording apparatus includes a carriage on which recording means (print head) and an ink tank are mounted, a transport means for transporting recording paper, and a control means for controlling them. A print head that ejects ink droplets from a plurality of ejection openings is serially scanned in the direction (main scanning direction) perpendicular to the conveyance direction of the recording paper (sub-scanning direction), while at the time of non-recording, the recording width is increased. The same length is intermittently conveyed. Further, in the case of a color inkjet recording apparatus, a color image is formed by superimposing ink droplets ejected by a plurality of color print heads.

  In an ink jet recording apparatus, a thermal method, a piezo method, or the like is known as a method for ejecting ink.

  The “thermal method” is provided with a heating element (electrical / thermal energy converter) in the vicinity of the discharge port, and by applying an electrical signal to the heating element, the ink is locally heated, causing a pressure change, In this method, ink is ejected from ejection ports.

  The “piezo method” is a piezo method in which an electrical / pressure converting means such as a piezo element is used, a mechanical pressure is applied to the ink, and the ink is ejected.

  In general, the thermal method makes it easy to increase the density of the nozzles and allows the head to be constructed at low cost, but uses heat, and thus tends to cause deterioration of the ink and the head. On the other hand, the piezo method is excellent in ejection controllability, has a high degree of ink freedom, and has a semi-permanent head life.

  In the recording method, characters, figures, and the like are recorded by ejecting ink as fine droplets from a discharge port onto a recording medium in accordance with a recording signal. Therefore, since it is non-impact, there are advantages such as low noise, low running cost, easy downsizing of the apparatus, and easy colorization. For this reason, it is widely used as an image forming (recording) means in a recording apparatus such as a copying machine, a printer, or a facsimile machine that is used in combination with a computer, a word processor, or the like, or used alone.

  In the conventional ink jet recording method, it is necessary to use a dedicated coated paper having an ink absorbing layer in order to obtain a color image with high color development without ink bleeding. In recent years, methods have been put to practical use that have the ability to print on plain paper that is used in large quantities in printers, copiers, etc., by improving ink and the like.

  In addition, it is desired to support various recording media such as OHP sheets, cloths, and plastic sheets. To meet these demands, when a recording medium (recording medium) with different ink absorption characteristics is selected as necessary, a recording apparatus that can perform the best recording regardless of the type of recording medium is developed. And commercialization is in progress.

  Further, regarding the size of the recording medium, a large-sized recording medium is required for woven fabrics such as posters and clothes for advertising. Such an ink jet recording apparatus has been increasingly demanded as an excellent recording means in a wide range of fields, and it has been demanded to provide a higher quality image, and the demand for higher speed has further increased.

  In general, the color ink jet recording method uses four color inks in which black (K) is added to three color inks of cyan (C), magenta (M), and yellow (Y) to perform color recording. Is realized. In such a color ink jet recording apparatus, unlike a monochrome ink jet recording apparatus that prints only characters, when recording a color image, various elements such as color developability, gradation, and uniformity are required. is there.

  In addition, in the ink jet recording apparatus, in addition to the conventional four colors of cyan (C), magenta (M), yellow (Y), and black (K), light C (LC) and light M (LM) with low ink density are used. , 7-color ink to which 3 colors of light Y (LY) are added is used. By doing so, a natural image can be formed with higher quality, and the graininess of the highlight portion can be reduced.

  Such a color inkjet recording apparatus includes an image forming controller and an image forming engine. The image forming controller realizes an interface for exchanging image information and various control information with a host PC and the like, generation of image forming data based on input image information, and the like. The image forming engine transports the recording paper and drives the carriage and controls the print head to form an image.

  However, the quality of the recorded image largely depends on the performance of the print head alone. The slight differences between nozzles that occur during the printhead manufacturing process, such as the shape of the printhead discharge port and the variation in the electrical / thermal converter (discharge heater), are dependent on the amount of ink discharged and the direction of the discharge direction. affect. This causes deterioration in image quality as density unevenness of a finally formed recorded image. As a result, there are “white” portions that cannot periodically satisfy the area factor of 100% in the head main scanning direction, and conversely, dots overlap more than necessary or white streaks occur. These phenomena are usually perceived as “density unevenness” by the human eye.

  Therefore, a method called “multi-pass recording method” is known as a countermeasure against such density unevenness. As a method for generating data (pass data) for each recording scan, there are a fixed mask method and a table reference method.

  The “fixed mask method” is a method of generating pass data by thinning out print data using an even number / odd number pattern or a staggered / inverted staggered pattern. The “table reference method” is a method of generating pass data by thinning out print data using a random mask pattern or the like in which print dots and non-print dots are randomly arranged. By recording one raster using two different nozzles, it is possible to form a high-quality image with reduced density unevenness.

  In addition, the “multi-pass printing method” has the effect of suppressing bleeding by printing while drying ink, and reduces the number of printing dots for each scan. There is an effect to suppress. Although the main scanning direction has been described here, it is possible to further improve the image quality by thinning out and recording continuous dots in the sub-scanning direction. Further, when realizing image formation in the sub-scanning direction at a resolution higher than the nozzle resolution, thinning recording is necessarily performed in the sub-scanning direction.

  In color ink jet recording apparatuses, there are increasing demands for higher image quality and higher speed. There are the following measures (1) to (4) for realizing high speed. (1) Increase in the number of nozzles included in the print head, (2) Improvement in carriage drive (main scanning) speed on which the print head is mounted, (3) Reduction in the number of recording passes for multi-pass printing, (4) Outward scan / return There is bidirectional recording in which an image is formed with both scanning.

  For each of the above measures (1) to (4), reduction in characteristic variation and increase in yield due to enlargement of the print head and high-density mounting of nozzles, improvement in basic performance such as further high-speed response and reduction in deflection, etc. Many parts depend on the performance of the print head itself.

  Furthermore, in order to make the countermeasures (3) and (4) compatible, there is a very big problem as follows. In other words, when so-called bi-directional printing in which image formation is performed for both forward scanning and backward scanning is performed with respect to multi-pass printing or one-pass printing such as 2, 4 pass printing, etc. Color unevenness occurs, and there is a problem that image quality is greatly deteriorated.

  Next, the mechanism of this phenomenon will be described in detail.

  2. Description of the Related Art A print head in a recent ink jet recording apparatus has a mainstream configuration in which nozzle rows are arranged in the sub-scanning direction for each ink color and are arranged in the main scanning direction, for example, for the ink color.

  FIG. 17 is a diagram showing a state of nozzle arrangement for each ink color.

  Here, 256 nozzles are mounted per row (color), and are arranged in the main scanning direction in the order of K, C, M, and Y. When bidirectional printing is performed with such a print head, as shown in FIG. 17, in the forward scan, the ejected ink droplets land on the paper surface in the order of K, C, M, and Y, and in the backward scan, Conversely, the ejected ink droplets land on the paper surface in the order of Y, M, C, and K.

  FIG. 18 is a schematic cross-section showing the state of ink permeation and fixing with respect to the recording paper when the M ink droplet reaches the paper surface after a short time interval following the C ink droplet in forward scanning. FIG.

  In general, ink droplets that are ejected later penetrate in the direction perpendicular to the paper surface and in the direction along the paper surface, but do not penetrate and fix so much in the region where the ink droplets that have landed earlier have penetrated. The ink droplets ejected later penetrate and fix further below the area where the ink droplets impregnated earlier penetrate. In other words, C permeates first, spreads on the surface and inside, and the next landed M sinks under the C ink. When viewed from the surface, the M ink spreads outside the C ink with M.

  FIG. 19 is a schematic cross-sectional view showing the state of ink permeation and fixing with respect to the recording paper when the C ink droplet reaches the paper surface at a short time interval following the M ink droplet in the backward scanning. It is.

  In the same manner as described above, M permeates first, spreads to the surface and inside, and then landed C enters under the M ink. When viewed from the surface, the C ink spreads outside the M ink with C. When attention is paid to a single dot, the C color appears more strongly than the CM mixed color portion in forward scanning. In this way, even in the same C-M color mixture, the forward scan and the backward scan have completely different colors.

  Next, a problem in multi-pass recording related to this phenomenon will be described by taking two-pass bidirectional recording as an example.

  In the forward scan, dots are formed in a zigzag pattern, and in the backward scan, dots are formed in a reverse zigzag pattern complementary to this, thereby realizing all dot formation in two scans.

  FIG. 20 is a diagram showing a state of recording scanning in two-pass bidirectional recording.

  As shown in FIG. 20, for each half band (band indicates the nozzle row width) that is the paper conveyance width, an area that is scanned in the order of forward scanning and backward scanning, and an area that is scanned in the order of backward scanning and forward scanning. And alternately exist. Here, if the dots are arranged at the staggered coordinate position and the reverse zigzag coordinate position almost evenly in a probability manner, they are formed by the forward scan and the backward scan, in other words, the first pass and the second pass. The number (ratio) of dots is equal.

  Here, it is common to form dots having a size larger than at least the circumscribed circle with respect to the adjacent pixel pitch determined by the recording resolution of the image. Furthermore, larger dots are used in consideration of landing deviation caused by deviation of ink discharge, paper transport error, etc., variation in the size of discharged ink droplets, and the like.

  FIG. 21 is a diagram illustrating a state of dots formed on the paper surface.

  As shown in FIG. 21, the dot formation area when 50% of the dots are ejected in a staggered pattern occupies 50% or more on the paper surface, and when the dot size is increased, the paper surface is almost completely filled.

  Therefore, as described above, when the two-pass bidirectional printing is executed, even if the number of dots formed in the preceding first pass is 50% in terms of quantity, the area actually formed is 50%. Cover the surface of the paper. That is, in the area where the forward scanning is preceded, the color in the forward scanning is dominant, and in the area where the backward scanning is preceded, the color in the backward scanning is dominant, so as a result, for each paper conveyance width, There is a problem in that mixed colors having different colors are alternately formed and the image quality is greatly impaired.

  Further, the difference in color between the forward scanning and the backward scanning greatly changes depending on the difference in density (dot injection amount). Such a delicate relationship between density and color varies in a complex manner depending on combinations of ejected ink droplet amount, adjacent pixel pitch, ink characteristics, recording medium characteristics, landing time difference of each ink color, and the like.

In order to solve such technical problems, an ink jet recording apparatus including a plurality of print heads has been proposed and put into practical use so that the landing order of inks of a plurality of colors is symmetric (for example, Patent Document 1, Patent) Reference 2). By disposing a plurality of sets of print heads with respect to the carriage movement direction and making the ink color arrangement symmetrical, the difference in the ink landing order between the forward scan and the backward scan is eliminated. In addition, the printing speed can be improved.
JP 2000-079681 A JP 2001-096770 A

  However, as described above, if the recording heads of each color are arranged so that the landing order of the inks of the plurality of colors is symmetric, the following problem occurs.

  That is, the print head or carriage and the cleaning mechanism become larger and more complicated, or the print head control circuit becomes larger, which is one factor that hinders cost reduction of the ink jet recording apparatus.

  The present invention efficiently suppresses color unevenness for each paper conveyance width during bidirectional printing, which is caused by a difference in color due to a difference in ink color landing order between forward scanning and backward scanning in a color inkjet recording apparatus. An object of the present invention is to provide an image forming controller that can be used.

Accordingly, the present invention can increase the image formation speed and quality.

The present invention provides a second command descriptor between successive first command descriptors at an image forming direction switching boundary, which is a boundary between a raster in which an image forming engine forms an image by forward scanning and a raster that forms an image by backward scanning. Insert. Thus, a profile switching control means for generating the third command descriptor is provided. In addition, the image processing unit sequentially generates the image forming data, transfers the forward path forming profile data, or transfers the backward path forming profile data based on the third command descriptor.

According to the present invention, in a color inkjet recording apparatus, color unevenness for each paper conveyance width during bidirectional recording due to a difference in color due to a difference in ink color landing order between forward scanning and backward scanning is efficiently suppressed. There is an effect that can be.

  The best mode for carrying out the present invention is the following embodiment.

  FIG. 1 is a diagram illustrating a configuration of a recording unit PR1 of an ink jet recording apparatus 100 that is Embodiment 1 of the present invention.

  The recording unit PR1 of the inkjet recording apparatus 100 includes a print head 701, a carriage 702, and paper feed rollers 703 and 704.

  The print head 701 includes four independent ink tanks containing black (K), cyan (C), magenta (M), and yellow (Y), and four independent ink tanks. It is comprised by the multihead which comprises a head. The number of nozzles for each color is 1280 nozzles.

  The carriage 702 supports the print head 701 and moves them. The carriage 702 is present at the home position HP shown in FIG.

  The paper feed roller 703 rotates with the auxiliary roller (not shown) while suppressing the recording paper 705, and feeds the recording paper 705 in the Y direction as needed.

  The paper feed roller 704 supplies the recording paper 705 and suppresses the recording paper 705 in the same manner as the paper feed roller 703 and the auxiliary roller. Here, the print head 701 has 256 nozzles respectively arranged in the paper feed direction for the four colors K, C, M, and Y (FIG. 17).

  Next, a basic bidirectional recording operation will be described.

  During standby, the carriage 702 existing at the home position HP discharges ink onto the recording paper 705 according to the recording data by a plurality of nozzles of the print head 701 while moving in the X direction according to a recording start command. ,Record.

  When the recording of the recording data to the end of the recording paper 705 is completed, the paper feed roller 704 rotates in the direction of the arrow to feed the paper by a predetermined width in the Y direction. Subsequently, the carriage 702 ejects and records ink while moving in the −X direction, and the carriage returns to the original home position position HP. Data recording is realized by repeating such scanning operation and paper feeding operation.

  FIG. 2 is a diagram illustrating that the ink jet recording apparatus 100 includes an image forming controller 801 and an image forming engine 802.

  The image forming controller 801 implements an interface for exchanging image information and various control information with a host PC or the like, and also creates image forming data based on input image information.

  An image forming engine 802 conveys recording paper and drives a carriage, controls a print head, and forms an image.

  In the ink jet recording apparatus 100 according to the first embodiment, 256 nozzles are arranged in the sub-scanning direction for each ink color, and the four ink colors are arranged in the main scanning direction in the order of K, C, M, and Y. The nozzle resolution of the print head is 1200 dpi, and the amount of ejected ink droplets is 4 pl as shown in FIG. So-called bi-directional printing is performed in which image formation is performed for both forward scanning and backward scanning, and dots are formed with a resolution of 1200 dpi × 1200 dpi in one pass.

  FIG. 3 is a diagram illustrating a recording scan state of the print head in bidirectional recording.

  First, after the 256 raster image is formed in the forward scan, the paper transport corresponding to 256 raster is performed. Subsequently, after the 256 raster image is formed in the backward scan, the paper transport corresponding to 256 raster is performed. By repeating this, bidirectional recording is realized. 256 rasters (outward print band) formed by only the forward scan and 256 rasters (backward print band) formed by the backward scan appear alternately.

  Next, a so-called page printer that analyzes information including color multi-value information of a page description language method in page units and outputs prints in page units in the first embodiment will be described.

  A page description language (hereinafter referred to as “PDL”) divides drawing data on a page into drawing elements such as characters, graphics, and images called objects, and converts them into object codes. This is language information for transferring information.

  Information to form an image is transmitted as PDL from the host PC, and the printer side interprets the received PDL data, generates and holds intermediate data called a display list, and performs rendering based on the intermediate data. Thereby, image information corresponding to the printing resolution is generated from various information. There are two types of PDL, which are characterized by an advanced graphics function typified by PostScript, and a type characterized by a high-speed processing function capable of printing at high speed, typified by LIPS and PCL.

  There are two methods for drawing PDL data. One method is a method called contone rendering, in which rendering processing is executed with RGB multilevel data (in many cases, each color is 8 bits), and the output data format is also RGB multilevel data.

  Another method is a method called halftone rendering. This halftone rendering is a display in which RGB multi-value data is converted into a color space in which black (K) is added to three colors of ink (cyan (C), magenta (M), yellow (Y)) desired by the engine. Generate a list. Further, the halftone process is performed prior to the rendering process.

  The output data format of the halftone rendering method is KCMY data subjected to gradation conversion. It is also possible to perform halftone processing before the display list.

  In the former contone rendering method, KCMY conversion and halftone processing are executed on the raster image after rendering processing, and thus there is an advantage that the degree of freedom of the image processing configuration and flow is high. On the other hand, in the latter halftone rendering method, color space conversion and halftone processing are performed during display list generation or rendering processing. Therefore, compared to the contone rendering method, various buffers can be configured with a smaller size. is there.

  FIG. 4 is a block diagram illustrating a schematic configuration of the image forming controller 801.

  The image forming controller 801 includes a CPU 301, a communication interface 302, a RAM 304, a ROM 305, an EEPROM 306, an operation panel interface 307, an operation panel 308, and an expansion interface 309. The image forming controller 801 includes an expansion card 310, a rendering unit 311, a lossless compression unit 312, a lossless decompression unit 313, a lossy compression unit 314, an irreversible decompression unit 315, an image processing unit 316, An engine interface 317.

  The image forming controller 801 employs a contone rendering method.

  The CPU 301 is connected to the host PC 303 via the communication interface 302, accesses the ROM 305 storing the control program, and controls the recording operation based on the information stored in the ROM 305.

  The CPU 301 accesses an EEPROM 306 storing an updatable control program, processing program, various constant data, and the like, and controls a recording operation based on information stored in the EEPROM 306. Further, the CPU 301 accesses a RAM 304 that stores a command signal and image information received from the host PC 303, and controls a recording operation based on the information stored in the RAM 304.

  The RAM 304 can expand the memory capacity by using an expansion port. Instruction information input from the keys of the operation panel 308 is transmitted to the CPU 301 via the operation panel interface 307. Further, in accordance with a command from the CPU 301, the LED lighting and LCD display of the operation panel 308 are controlled through the operation panel interface 307 in the same manner as described above.

  The expansion interface 309 is an interface that performs function expansion by connecting an expansion card 310 such as an HDD. The rendering unit 311 interprets the intermediate data (display list) generated by the CPU 301 and creates a raster image and attribute bits corresponding to each pixel.

  The irreversible compression unit 314 encodes the raster image in an irreversible manner. The irreversible decompression unit 315 decodes the raster image that has been compression-encoded by the irreversible method. The lossless compression unit 312 encodes the attribute bits using a lossless method, and the lossless decompression unit 313 decodes the attribute bits that have been compression encoded using the lossless method. Based on the attribute bits, the image processing unit 316 performs optimal image processing according to the object type such as characters and graphics, and generates and outputs image formation data of each ink color that conforms to the engine specifications.

  The image forming data is sent to the image forming engine 802 via the engine interface 317.

  Next, PDL processing and image processing focusing on the image forming controller 801 will be described in detail.

  FIG. 5 is a flowchart showing the basic data processing operation in the image forming controller 801.

  The PDL data received from the host PC is converted into a raster image according to a display list that is intermediate data interpreted and generated, and further converted into dot data in a format suitable for image formation by the engine.

  The “PDL data” is image data in which the contents of rendering are described, and is divided into font data representing characters and numbers, vector data representing geometric line drawings, various bitmap image data such as natural images, and the like. The

  First, when various types of PDL data are received from the host PC, the CPU analyzes the PDL data (401) and converts it into intermediate data (display list) for high-speed rendering processing (402).

  The display list buffer allocated to the RAM normally stores a display list for one page (403). Subsequently, in accordance with the generated and stored display list, conversion processing is performed into a raster image of RGB each color of 8 bits (404).

  The rendering resolution is 600 dpi × 600 dpi. Raster image conversion processing for each band is performed in accordance with a display list for each band, which is a raster number smaller than one page. The raster image and attribute bits that are the rendering processing result are temporarily stored (405) in the drawing buffer, and then compression-encoded (406) using the lossy method and the lossless method, respectively, and held in the page buffer. (407).

  When printing, the compressed data held in the page buffer is read, decoded (408), and temporarily stored in the image processing buffer (409). Then, image processing, that is, color processing (410) and halftone processing (411) are performed on the RGB multi-value data while referring to the attribute data, and 1-bit data of each color in the output resolution KCMY format is generated. .

  The forward recording table (412) is a color conversion table applied to an area where image formation is performed in forward scanning, and the backward recording table (413) is a color conversion table applied to an area where image formation is performed during backward scanning. is there. In the color processing (410), the 14-bit data of each color in the KCMY format is generated by selectively using the forward recording table (412) and the backward recording table (413) (details will be described later). Halftone processing (411) is processing for generating binary data of output resolution by combining multi-value dither processing and matrix development processing. In the first embodiment, each color is converted into 1-bit data in the KCMY format of 1200 dpi × 1200 dpi using a 2 × 2 size matrix. The generated dot data is transferred to the engine.

  FIG. 6 is a block diagram for explaining the image forming controller 801 shown in FIG. 4 in detail.

  The image forming controller 801 is connected to the CPU 101, the memory control unit 102, and the memory 103 via the internal bus 104.

  In response to the setting control from the CPU 101, the image forming controller 801 reads the RGB multi-value data temporarily stored in the memory 103 according to a predetermined parameter, converts it into KCMY binary data, and re-stores it in the memory.

  The image forming controller 801 includes a data input unit 111, a data output unit 112, a CSC unit 113, a CSC table 114, an output gamma correction unit 115, a gamma table 116, a multi-value dither unit 117, and a dither table 118. And have. The image forming controller 801 includes a binary development unit 119, a matrix table 120, a basic parameter storage unit 121, a descriptor storage unit 122, and an overall control unit 123.

  The data input unit 111 is responsible for the internal bus 104 interface control and implements input DMA transfer processing. In accordance with an instruction from the overall control unit 123, image data, basic control data, or control data is input and transferred via the internal bus 104.

  The data output unit 112 is responsible for internal bus 104 interface control and implements output DMA transfer processing. In accordance with an instruction from the overall control unit 123, the image data is output and transferred via the internal bus 104.

  The CSC unit 113 realizes color space conversion of the input RGB multilevel image information. The CSC table 114 realized by the RAM is used for color space conversion in the CSC unit 113. The output gamma correction unit 115 executes gamma correction of KCMY multilevel image information that is an output of the CSC unit 113.

  The gamma table 116 implemented by the RAM is used for gamma correction processing in the output gamma correction unit 115. The multi-value dither unit 117 realizes halftone processing of KCMY multi-value image information based on the multi-value dither method.

  The dither table 118 realized by the RAM is used for halftone processing in the multi-value dither unit 117. The binary developing unit 119 generates KCMY binary data of output resolution using a matrix table.

  The matrix table 120 realized by the RAM is used for matrix development in the binary development unit 119. The basic parameter storage unit 121 stores basic control data that is set and controlled from the CPU 101 via the internal bus 104.

  The descriptor storage unit 122 stores the command descriptor fetched from the memory. The overall control unit 123 monitors an external control signal and an internal state, and gives an operation instruction to each unit.

  Next, a basic image processing operation flow will be described.

  The image forming controller 801 can perform a chain operation in which a single or a plurality of command descriptors stored in the memory 103 are automatically fetched sequentially and sequentially executed while being interpreted.

  First, basic parameters are written from the CPU 101 to the basic parameter storage unit 121. After the basic parameter writing is completed, when the CPU 101 gives an instruction to start the operation, the first command descriptor is fetched. The overall control unit 123 instructs execution of the image data processing mode or the RAM table transfer mode in response to the fetched command descriptor.

  Next, an outline of the command descriptor 200 will be described.

  FIG. 7 is a diagram illustrating the command descriptor 200.

  The command descriptor 200 includes descriptor identification information 201, command information 202, chain transition information 203, data input information 204, data output information 205, data processing information 206, and table input information 207.

  The descriptor identification information 201 includes an identification code, a chain number, and the like. The command information 202 includes a mode to be executed, an interrupt control parameter, and the like. The chain transition information 203 includes a transition condition to the next chain, a command descriptor storage source address for the next chain, and the like.

  The data input information 204 is composed of the storage source address, size, data format, and the like of the input image data or input table data in the memory 103. The data output information 205 is used only in the image processing mode, and includes the storage destination address, size, data format, and the like of the output image data in the memory 103.

  The data processing information 206 is used only in the image processing mode, and includes processing parameters in the CSC unit 113, the output gamma correction unit 115, the multi-value dither unit 117, and the binary development unit 119. The table input information 207 is used only in the RAM table transfer mode, and includes an internal storage destination of input RAM table data.

  Next, basic processing in the image data processing mode that is the first operation mode will be described.

  The “image processing mode” is a mode in which image data in RGB multi-value format stored in the memory 103 is read, converted into dot data in KCMY binary format, and then stored in the memory 103 again. The RGB multi-value data stored in the memory 103 is input via the internal bus 104 and the data input unit 111 and supplied to the CSC unit 113. The CSC unit 113 performs color space conversion using the CSC table 114.

  The KCMY multilevel data that is the output of the CSC unit 113 is input to the output gamma correction unit 115 and subjected to gamma correction processing using the gamma table 116.

  The multi-value dither unit 117 performs N-value processing (N> 2) for KCMY multi-value data. Here, the multi-value dither method using the dither table 118 is adopted. Further, the binarization development unit 119 uses the matrix table 120 to implement the development process to the output resolution binary format. The generated dot data of the output resolution is written into the memory 103 via the data output unit 112 and the internal bus 104. The rendering resolution is 600 dpi × 600 dpi, and the binary development unit 119 generates 1-bit data of KCMY colors with an output resolution of 1200 dpi × 1200 dpi using a 2 × 2 matrix. The generated dot data is transferred to the engine.

  Next, the basic data flow in the RAM table transfer mode, which is the second operation mode, will be described.

  The “RAM table transfer mode” is a mode in which table data used for image processing stored in the memory 103 in advance is read and transfer / update processing is performed. Table data stored in the memory 103 is input via the internal bus 104 and the data input unit 111. Transfer processing to a specified single or plural RAM tables from the CSC table 114, the gamma table 116, the dither table 118, and the matrix table 120 is realized.

  Consider a case where the next chain transition prohibition (chain operation end) is designated as the chain transition information 203 included in the command descriptor. In this case, when the processing described in the command descriptor is completed, the image forming controller 801 outputs an interrupt request signal to the CPU 101 and completes the operation.

  A relationship between the table switching and the print band boundary in the CSC unit 113, which is characteristic in the present invention, will be described.

  As described above, in the one-pass bidirectional recording, the forward recording area of 256 rasters and the backward recording area of 256 rasters appear alternately. In the forward scan, the ejected ink droplets land on the paper surface in the order of K, C, M, and Y. In the backward scan, the ejected ink droplets land on the paper surface in the reverse order of Y, M, C, and K. As a result, periodic color unevenness occurs between the forward recording area and the backward recording area.

  In the first embodiment, a color conversion profile for forward scanning and a color conversion profile for backward scanning are provided, and these are switched and applied so that the colors of the forward recording area and the backward recording area are matched (approached). ) To eliminate annoying unevenness.

  Specifically, profile switching is realized by appropriately changing the profile data set in the CSC table 114 used in the CSC unit 113. The CSC table 114 is updated between the RGB multi-value data rasters that coincide with the print band boundary. The setting is changed to the profile data for the backward pass in synchronization with the boundary between the forward scan band and the backward scan band, and the setting is changed to the profile data for the forward pass in synchronization with the boundary between the backward scan band and the forward scan band. Since the output resolution is 1200 dpi and the rendering resolution is 600 dpi, the print band boundary appears every 256 rasters, whereas the CSC table is updated every 128 rasters. As a result, a color conversion profile for forward scanning can be applied to the forward scanning area, and a color conversion profile for backward scanning can be applied to the backward scanning area.

  FIG. 8 is a diagram illustrating a state in which a command descriptor for the RAM table transfer mode is inserted into the command descriptor for the image processing mode.

  Between raster # (M-1) and raster # (M) corresponds to the print band boundary, and thereafter, it is synchronized with the print band boundary at 128 raster cycles in the RGB multi-value data format. Show. In this way, the command descriptor is generated and controlled, and the profile data update process is inserted between the raster image processes and automatically executed. Thus, there is no overhead such as interrupt response processing by the CPU at the profile switching timing, and switching processing between the forward scanning profile and the backward scanning profile becomes possible.

As described above, the command descriptor is generated so that the setting change of the profile data is synchronized with the print band boundary in the PDL inkjet recording apparatus corresponding to the page description language. As a result, a color conversion process using a profile according to the recording scan direction of the print band is executed. Therefore, overhead associated with profile switching does not occur, and color unevenness caused by a difference in ink landing order in so-called bidirectional printing in which image formation is performed between forward scanning and backward scanning can be avoided and suppressed. That is, it is possible to provide an excellent image forming controller 801 capable of realizing high-speed and high-quality image formation.

  The first embodiment is an ink jet recording apparatus that has 256 nozzles (1200 dpi) for each color and realizes one-pass bidirectional recording. In the first embodiment, change control of a color conversion profile at a rendering resolution of 600 dpi is performed by synchronizing insertion of a command descriptor corresponding to profile switching with a print band boundary in which the scanning direction is switched.

  In the second embodiment of the present invention, command descriptor insertion control corresponding to profile switching is switched corresponding to a plurality of print modes.

  FIG. 9 is a diagram illustrating the drawing resolution, the output resolution, the number of passes / scanning, and the number of nozzles for the “fast mode” and the “clean mode” in the second embodiment.

  In the second embodiment, there are two print modes, “fast mode” and “clean mode”, and these are selectively used to form an image. The “fast mode” is a mode in which one-pass bidirectional recording is performed at a rendering resolution of 300 dpi × 300 dpi and an output resolution of 1200 dpi × 1200 dpi. The “clean mode” is a mode in which two-pass bidirectional recording is performed at a rendering resolution of 1200 dpi × 1200 dpi and an output resolution of 2400 dpi × 1200 dpi (see FIG. 9).

  As described above, even in bi-pass multi-pass printing with a small number of passes such as two passes, color unevenness for each paper conveyance width may be recognized as in the case of one-pass bi-directional printing. In multi-pass printing, the profile data applied to the area preceded by the forward scan and the profile data for the area preceded by the backward scan are switched and used.

  The recording unit of the ink jet recording apparatus in Example 2 is the same as that in Example 1 (see FIG. 1). The basic configuration of the ink jet recording apparatus is the same as that of the first embodiment (see FIGS. 2 and 4).

  The state of print scanning of the print head in the “fast mode” is the same as that in the first embodiment (see FIG. 3). First, after the 256 raster image is formed in the forward scan, the paper transport corresponding to 256 raster is performed. Subsequently, after the 256 raster image is formed in the backward scan, the paper transport corresponding to 256 raster is performed. By repeating these, bidirectional recording is realized. 256 rasters (outward print band) formed by only the forward scan and 256 rasters (backward print band) formed by the backward scan appear alternately.

  FIG. 10 is a diagram illustrating a recording scan state of the print head in the “clean mode”.

  First, paper formation equivalent to 128 rasters is performed after 256 raster image formation (50% duty) in the forward scan, and then 128 rasters after 256 raster image formation (50% duty) in the backward scan. Carry out a considerable amount of paper. By repeating these, bidirectional recording is realized. 128 rasters (forward print band) for performing image formation in advance in the forward scan and 128 rasters (return print band) for performing image formation in advance in the backward scan appear alternately.

  The basic data processing in the image forming controller 801 is the same as the basic data processing in the image forming controller 801 in the first embodiment (see FIG. 5).

  In the “fast mode”, rendering is performed at a resolution of 300 dpi × 300 dpi, and finally, 1 × bit data in KCMY format of 1200 × 1200 dpi is generated using a 4 × 4 matrix. On the other hand, in the “clean mode”, rendering is performed at a resolution of 1200 × 1200 dpi, and finally, 1-bit data in KCMY format of 2400 × 1200 dpi is generated using a 2 × 1 matrix.

  Next, the relationship between the table switching in the CSC unit 113 and the print band boundary, which is characteristic in the present invention, will be described.

  The block configuration of the image forming controller 801 is the same as the block configuration of the image forming controller 801 in the first embodiment (see FIG. 6).

  As described above, in the “fast mode”, the forward recording area of 256 rasters and the backward recording area of 256 rasters appear alternately. On the other hand, in the “clean mode”, a 128-raster forward path preceding recording area and a 128-raster backward path preceding recording area appear alternately.

  In the second embodiment, in each mode, the color conversion profile for forward (preceding) recording and the color conversion profile for backward (preceding) recording are respectively switched and applied, so that the color colors between the regions are matched (approached). ) To eliminate annoying unevenness.

  Specifically, profile switching is realized by appropriately changing the profile data set in the CSC table 114 used in the CSC unit 113. The CSC table 114 is updated between the RGB multi-value data rasters that coincide with the print band boundary. In other words, the setting is changed to the profile data for the backward path in synchronization with the boundary between the forward scanning band and the backward scanning band, and the setting is changed to the profile data for the forward path in synchronization with the boundary between the backward scanning band and the forward scanning band. To do.

  In the “fast mode”, since the rendering resolution is 300 dpi with respect to the output resolution of 1200 dpi, the print band boundary appears every 256 rasters, whereas the CSC table is updated every 64 rasters.

  In the “clean mode”, since the rendering resolution is 1200 dpi with respect to the output resolution 1200 dpi, the print band boundary appears every 128 rasters, whereas the CSC table is updated every 128 rasters. As a result, a color conversion profile for forward scanning can be applied to the forward scanning area, and a color conversion profile for backward scanning can be applied to the backward scanning area.

  FIG. 11 is a diagram illustrating a state in which the command descriptor for the RAM table transfer mode is inserted into the command descriptor for the image processing mode in the “fast mode”.

  Between raster # (P-1) and raster # (P) corresponds to the print band boundary, and thereafter, it is synchronized with the print band boundary at 64 raster cycles in the RGB multi-value data format. Show.

  FIG. 12 is a diagram illustrating a state in which the command descriptor for the RAM table transfer mode is inserted in the command descriptor for the image processing mode in the “clean mode”.

  Between raster # (Q-1) and raster # (Q) corresponds to the print band boundary, and thereafter indicates that the print band boundary is synchronized with 128 raster cycles in the RGB multi-value data format. ing.

  In this way, by generating and controlling command descriptors, inserting profile data update processing between raster image processing, and automatically executing them, there is no overhead such as interrupt response processing by the CPU at profile switching timing. In addition, it is possible to switch between the forward scanning profile and the backward scanning profile.

  That is, in the PDL inkjet recording apparatus that supports the page description language, the profile data setting change is synchronized with the print band boundary according to the relationship between the rendering resolution, the output resolution, and the number of recording passes for each image forming mode. Create a command descriptor.

As a result, a color conversion process using a profile according to the recording scan direction of the print band is executed. Therefore, image formation can be performed in both forward scanning and backward scanning without causing overhead associated with profile switching. That is, it is possible to provide an excellent image forming controller 801 capable of avoiding and suppressing color unevenness due to a difference in ink landing order in so-called bidirectional recording and realizing high-speed and high-quality image formation.

  Embodiments 1 and 2 are embodiments that are applied to an ink jet recording apparatus that supports 256 page nozzles (1200 dpi) for each page and that realizes bidirectional recording.

  The third embodiment of the present invention is an ink jet recording apparatus that supports a raster language, detects a blank raster area in which no dot to be printed exists, and generates a command descriptor corresponding to profile switching corresponding to optimization of the recording scanning area. It is an Example which switches insertion control.

  The recording unit of the ink jet recording apparatus in Example 3 is the same as the recording unit of the ink jet recording apparatus in Example 1 (see FIG. 1). The basic configuration of the ink jet recording apparatus is the same as that of the ink jet recording apparatus in the first embodiment (see FIG. 2).

  FIG. 13 is a block diagram illustrating a schematic configuration of the image forming controller 801.

  An image forming controller 1801 based on the third embodiment inputs raster format image information and supplies dot data suitable for the image forming engine.

  The CPU 1301 is connected to the host PC 1303 via the communication interface 1302, accesses the ROM 1305 storing the control program, and controls the recording operation based on the information stored in the ROM 1305.

  The CPU 1301 accesses an EEPROM 1306 storing an updatable control program, a processing program, various constant data, and the like, and controls a recording operation based on information stored in the EEPROM 1306. Further, the CPU 1301 accesses a RAM 1304 for storing command signals and image information received from the host PC 1303, and controls the recording operation based on the information stored in the RAM 1304.

  The RAM 1304 can expand the memory capacity by using an expansion port. Instruction information input from the keys of the operation panel 1308 is transmitted to the CPU 1301 via the operation panel interface 1307. In addition, the input instruction information similarly controls LED lighting and LCD display of the operation panel 1308 via the operation panel interface 1307 according to a command from the CPU 1301.

  The expansion interface 1309 is an interface for performing function expansion by connecting an expansion card 1310 such as an HDD. The input image expansion unit 1311 decodes the compressed raster image input from the host PC. Further, the input image expansion unit 1311 detects that the expansion result is a blank raster, and notifies the CPU 1301 of it. Note that the CPU 1301 interprets and detects a blank raster designated at the command level. The decompressed raster image is supplied to the image processing unit 1312 and subjected to optimal image processing to generate and output image formation data of each ink color that conforms to the engine specifications. The image forming data is sent to the image forming engine 1314 via the engine interface 1313.

  Next, image processing focused on the image forming controller 1801 will be described in detail.

  FIG. 14 is a flowchart showing the basic data processing operation in the image forming controller 1801.

  In Embodiment 3, image information developed into a raster image by the host PC is transferred to the ink jet recording apparatus, converted into dot data in a format suitable for image formation by the engine, and supplied to the engine.

  Assume that the rendering resolution in the host PC, which is the input resolution of the inkjet recording apparatus, is 600 dpi × 600 dpi.

  The compressed raster data and command are received from the host PC, the compressed raster image is subjected to decoding processing (1401), and the raster image in RGB multi-value format is stored in the image processing buffer (1402).

  If a blank raster is detected in the decoded raster image, the CPU is notified. Note that the command information analyzed by the CPU includes a blank raster insertion command, and information regarding a blank raster to be inserted into the raster image can be acquired. The blank raster included in the command information or the raster image is not stored in the image processing buffer.

  The RGB multilevel data temporarily stored in the image processing buffer is subjected to image processing, that is, color conversion (1403) and halftone processing (1404), and converted into 1-bit data of each color in the KCMY format.

  The forward recording table (1405) is a color conversion table applied to an area where image formation is performed in forward scanning, and the backward recording table (1406) is a color conversion table applied to an area where image formation is performed during backward scanning. is there.

  In the color conversion process (1403), by using the forward recording table (1405) and the backward recording table (1406) selectively (details will be described later), 14-bit data of each color in KCMY format is generated. The halftone processing (1404) generates binary data of output resolution by combining multi-value dither processing and matrix development processing. That is, in the third embodiment, each color is converted into 1-bit data in the KCMY format of 1200 dpi × 1200 dpi by a 2 × 2 size matrix. The generated dot data is transferred to the engine.

  Next, the relationship between the table switching in the CSC unit 113 and the print band boundary, which is characteristic in the third embodiment, will be described.

  The block configuration of the image forming image forming controller 1801 in the third embodiment is basically the same as the block configuration of the image forming controller 801 (FIG. 6) in the first embodiment.

  First, after the 256 raster image is formed in the forward scan, the paper transport corresponding to 256 raster is performed. Subsequently, after the 256 raster image is formed in the backward scan, the paper transport corresponding to 256 raster is performed. By repeating this, one-pass bidirectional recording is realized. In such a case, as a result, 256 rasters (outward print band) formed by only the forward scan and 256 rasters (return print band) formed by the backward scan appear alternately.

  Further, the third embodiment has a function of optimizing the scanning direction control for the blank raster detected by the CPU or the input image decoding unit.

  Next, a recording operation in response to blank raster detection will be described with an example.

  FIG. 15 is a diagram illustrating a case where only 1200 rasters are present after 90 rasters to be recorded in the forward scan below the 256 backward scan rasters.

  In the case shown in FIG. 15, the backward scanning area 256 raster appears after the forward scanning area 90 raster (with the blank 1200 raster in between). Corresponding to such optimization control in the scanning direction, the color conversion profile for forward (preceding) recording and the color conversion profile for backward (preceding) recording are switched and applied to each region. Match the colors of the eyes (close to each other) to eliminate annoying unevenness.

  Specifically, profile switching is realized by appropriately changing the profile data set in the CSC table 114 used in the CSC unit 113. The CSC table 114 is updated between the RGB multi-value data rasters that coincide with the print band boundary. The setting is changed to the profile data for the backward pass in synchronization with the boundary between the forward scan band and the backward scan band, and the setting is changed to the profile data for the forward pass in synchronization with the boundary between the backward scan band and the forward scan band.

  When there is no blank raster area, as shown in FIG. 3, since the rendering resolution is 600 dpi with respect to the output resolution 1200 dpi, a print band boundary appears every 256 rasters. On the other hand, the CSC table is updated every 128 rasters. As a result, the color conversion profile for forward scanning can be applied to the forward scanning area, and the color conversion profile for backward scanning can be applied to the backward scanning area.

  When a blank raster area exists, as shown in FIG. 15, the CSC table update control is switched as the print band boundary moves. As a result, the color conversion profile for forward scanning is applied to 45 rasters with a rendering resolution of 600 dpi and then the color conversion profile for backward scanning for backward scanning is applied to the forward scanning area 90 raster with an output resolution of 1200 dpi. be able to.

  FIG. 16 is a flowchart showing an operation of inserting the command descriptor for the RAM table transfer mode into the command descriptor for the image processing mode, corresponding to the case shown in FIG.

  Between raster # (S-1) and raster # (S) corresponds to a print band boundary, and thereafter indicates that the print band boundary is synchronized with 64 raster cycles in the RGB multi-value data format. .

  As described above, command descriptor generation control is performed and profile data update processing is inserted between raster image processing and executed automatically, so there is no overhead such as interrupt response processing by the CPU at profile switching timing. In addition, it is possible to switch between the forward scanning profile and the backward scanning profile.

As described above, the command descriptor is generated so that the profile data setting change is synchronized with the print band boundary in response to the blank raster detection in the raster language compatible inkjet recording apparatus. As a result, a color conversion process using a profile according to the recording scan direction of the print band is executed. Therefore, it is possible to form an image in both forward scanning and backward scanning without causing overhead associated with profile switching. That is, it is possible to provide an excellent image forming controller 1801 capable of avoiding and suppressing color unevenness due to a difference in ink landing order in so-called bidirectional recording and realizing high-speed and high-quality image formation.

  Examples 1, 2, and 3 are image forming controllers 801 that are connected to an ink jet print engine using K, C, M, and Y color inks.

  The fourth embodiment of the present invention is an embodiment that does not limit the number of colors and color types installed in a connected print engine. Three colors of ink other than K may be used. Light colors such as light cyan (LC), light magenta (LM), light yellow (LY), and light black (LB), red (R), blue (B ) And other special colors may be added. Further, the print heads to be mounted are not limited to one set (one for each color), and can be applied to a print engine that includes a plurality of print heads for some or all ink colors and realizes high-speed printing.

  In the third embodiment, the print band, profile, and switching are synchronized in response to the optimum scanning control for the blank raster in the raster language compatible inkjet recording apparatus.

  The fourth embodiment is an embodiment in which the print band and the profile responding to the optimum scanning control for the blank raster are switched and synchronized in the ink jet recording apparatus corresponding to the page description language.

  Further, in the second embodiment, profile switching is performed in both “fast mode” in which 1-pass bidirectional recording is performed and “clean mode” in which 2-pass bidirectional recording is performed, and image formation is performed. However, it is also possible to select an image forming mode that does not involve profile switching, and the number of passes is not limited to 1 and 2. The present invention can also be applied to an ink jet recording apparatus that supports raster languages as in the third embodiment.

  In the first, second, and third embodiments, display list generation processing, rendering processing, image formation data generation processing, and the like are all performed inside the inkjet recording apparatus. However, some or all of these may be realized by a driver on the connected host PC side or other external device.

  In the first, second, and third embodiments, the image forming controller is connected to a single image forming engine. However, an image forming controller that can be selectively connected to a plurality of image forming engines may perform image switching by performing profile switching according to the connected image forming engines.

  Further, in Examples 1, 2, and 3, finally, an image is formed using single-size dots based on binary image data (binary recording). However, based on three or more multi-value image data, dots of different sizes are selectively formed to complete an image (multi-value recording), or overprinting of the same size ink is performed. Also good.

  The present invention is not limited by the operation principle or configuration of the print head. That is, the print head is provided with a heating element (electrical / thermal energy conversion element) in the vicinity of the ejection opening, and by applying an electrical signal to the heating element, the ink is locally heated, causing a pressure change, A thermal method in which ink is ejected from an ejection port may be used. Further, a piezo method may be used in which an electrical / pressure converting means such as a piezo element is used to apply a mechanical pressure to the ink and eject the ink.

  The above embodiment is an ink jet type image forming system, but an applicable image forming system is not limited to the ink jet type. In other words, as long as the difference in color or the like can be visually recognized because the order of overlaying recording agents such as ink is different in the scanning direction of the forward path and the backward path, it can be applied to other serial scanning image forming systems. You may make it do.

In addition, the present invention is not limited to an image output device of an information processing apparatus such as a computer or a word processor, and is not limited to an integrated or separate image output device, but also a copying apparatus combined with a reading apparatus and a facsimile apparatus having a communication function. Etc.

1 is a diagram illustrating a configuration of a recording unit PR1 of an inkjet recording apparatus 100 that is Embodiment 1 of the present invention. FIG. FIG. 2 is a diagram showing that the inkjet recording apparatus 100 includes an image forming controller 801 and an image forming engine 802. It is a figure which shows the mode of the recording scan of the print head in bidirectional | two-way recording. 2 is a block diagram illustrating a schematic configuration of an image forming controller 801. FIG. 5 is a flowchart showing basic data processing operations in the image forming controller 801. FIG. 5 is a block diagram for explaining in detail an image forming controller 801 shown in FIG. 4. It is a figure which shows the command descriptor. It is a figure which shows a mode that the command descriptor for RAM table transfer modes is inserted in the command descriptor for image processing modes. In Example 2, it is a figure which shows drawing resolution, output resolution, the number of passes / scanning, and the number of nozzles about "fast mode" and "clean mode". FIG. 4 is a diagram illustrating a recording scan state of a print head in a “clean mode”. FIG. 10 is a diagram illustrating a state in which a command descriptor for a RAM table transfer mode is inserted into a command descriptor for an image processing mode in “fast mode”. FIG. 9 is a diagram illustrating a state in which a command descriptor for a RAM table transfer mode is inserted into a command descriptor for an image processing mode in “clean mode”. 2 is a block diagram illustrating a schematic configuration of an image forming controller 801. FIG. 10 is a flowchart showing basic data processing operations in the image forming controller 1801. It is a figure which shows the case where only a blank raster exists after 90 rasters which should be recorded by a forward scan below the backward scan 256 rasters. 16 is a flowchart showing an operation of inserting a command descriptor for a RAM table transfer mode into a command descriptor for an image processing mode corresponding to the case shown in FIG. It is a figure which shows the mode of nozzle arrangement | positioning of each ink color. FIG. 5 is a schematic cross-sectional view showing how ink penetrates and fixes on a recording sheet when an M ink droplet reaches the paper surface at a short time interval following a C ink droplet in forward scanning. FIG. 5 is a schematic cross-sectional view showing how ink permeates and fixes on a recording sheet when a C ink droplet arrives on the paper surface at a short time interval following an M ink droplet in backward scanning. It is a figure which shows the mode of the recording scan of 2 pass bidirectional | two-way recording. It is a figure which shows the mode of the dot formed on a paper surface.

Explanation of symbols

PR1: a recording unit of the ink jet recording apparatus,
100: Inkjet recording apparatus,
200 ... command descriptor,
301 ... CPU,
305 ... ROM,
307: Operation panel interface,
308 ... Control panel,
311: Rendering unit,
316 ... an image processing unit,
801. Image forming controller,
802. Image forming engine.

Claims (8)

In an image formation controller that generates image formation data based on input image information and supplies it to an image formation engine,
A color conversion profile for forming an outward path for image formation;
A color conversion profile for backward path formation for forming an image by backward scanning;
A plurality of first command descriptors for generating the image forming data;
A second command descriptor for transferring the outward path forming profile data or the backward path forming profile data;
The second command descriptor is placed between successive first command descriptors at an image forming direction switching boundary that is a boundary between a raster that the image forming engine forms an image by forward scanning and a raster that forms an image by backward scanning. Profile switching control means for inserting and generating a third command descriptor;
Image processing means for sequentially executing generation of the image formation data, transfer of the forward path formation profile data, or transfer of the backward path formation profile data based on the third command descriptor;
An image forming controller comprising: In an image forming controller that generates image forming data based on input image information and supplies the image forming data to an image forming engine,
A color conversion profile for forward path advance formation for performing image formation in advance by forward path scanning;
A color conversion profile for backward path formation for performing image formation in advance by backward path scanning;
A plurality of first command descriptors for generating the image forming data;
A second command descriptor for executing transfer of the forward path advance formation profile data or the backward path advance formation profile data;
In the image forming engine, between successive first command descriptors at an image forming direction switching boundary, which is a boundary between a raster formed in advance by forward scanning and a raster formed in advance by backward scanning. Profile switching control means for inserting the second command descriptor and generating a third command descriptor;
Image processing means for sequentially executing generation of the image formation data, transfer of the forward path formation profile data, or transfer of the backward path formation profile data based on the third command descriptor;
An image forming controller comprising: In claim 1 or claim 2,
Has multiple modes of operation,
The profile switching control means is means for inserting the second command descriptor between successive first command descriptors at an image forming direction switching boundary corresponding to the operation mode. . In claim 1 or claim 2,
Blank raster detection means for detecting whether each raster is a raster indicating a blank;
The profile switching control means is means for inserting the second command descriptor between successive first command descriptors at an image forming direction switching boundary corresponding to a detection result by the blank raster detecting means. An image forming controller. In any one of Claims 1-4,
An image forming engine that employs a method of forming an image by ejecting ink drops and forming dots at each pixel by causing a change in state of the ink using thermal energy is connected. An image forming controller. In any one of Claims 1-4,
An image forming controller connected to an image forming engine that employs a method of forming an image by ejecting ink droplets by operating a pressure generating element and forming dots at each pixel. . In a control method of an image forming controller that generates image forming data based on input image information and supplies the image forming data to an image forming engine,
Between the successive first command descriptors that generate image formation data at the image forming direction switching boundary that is the boundary between the raster that the image forming engine forms an image by forward scanning and the raster that forms an image by backward scanning. A profile switching control step of generating a third command descriptor by inserting a second command descriptor for transferring the forming profile data or the return path forming profile data;
An image processing step of sequentially executing generation of the image formation data, transfer of the forward path formation profile data, or transfer of the backward path formation profile data based on the third command descriptor;
A control method for an image forming controller, comprising: In a control method of an image forming controller that generates image forming data based on input image information and supplies the image forming data to an image forming engine,
In the image forming engine, generation of image forming data is executed at an image forming direction switching boundary that is a boundary between a raster that is preceded by forward scanning and an image that is preceded by backward scanning. Switching control for generating a third command descriptor by inserting a second command descriptor for executing transfer of forward path leading formation profile data or backward path leading formation profile data between consecutive first command descriptors Process and;
An image processing step of sequentially executing generation of the image formation data, transfer of the forward path formation profile data, or transfer of the backward path formation profile data based on the third command descriptor;
A control method for an image forming controller, comprising:

Images