JP4757329B2 - Image output device - Google Patents

Description

  The present invention relates to a technique for forming a color image based on print data described in a page description language.

  Conventionally, in color printers with different output speeds for color output and monochrome output, in order to improve the total throughput of the printing process, it is determined whether each page is a monochrome page or a color page for data containing both monochrome pages and color pages. Things have been done.

  In addition, if a page consisting only of grayscale is output in color, overprinting with CMYK toners will be performed, resulting in a decrease in print quality, and color MFPs have different maintenance fees for color output and monochrome output. There are cases where it is set, and there are cases where counting is performed contrary to the user's expectation.

In order to deal with these problems, the CMY value used on each page is examined, and if CMY value is detected, it is determined that the color is used, or if the input RGB values used on each page are equal, monochrome This problem has been solved by additionally introducing a method for determining the gray level and a mechanism for compensating for gray in color management.

  However, in the case of a page description language having various input color spaces such as PostScript (registered trademark) or color management using an ICC (International Color Consortium) profile, the user can create a gray page on the application. Even when configured intentionally, there were cases where not only black but also cyan, magenta, and yellow components were delicately output due to color processing calculation errors, resulting in color output.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a technique for determining whether color or monochrome with high accuracy in order to improve the throughput of printing processing.

In order to solve this problem, for example, an image output apparatus of the present invention has the following configuration. That is,
An image output device that generates and prints bitmap data of a page represented by CMYK which is a recording color component according to print data of a page description language,
Is greater than any one of the threshold color values of CMY represented by the print data, the page of interest to determine the color page, if all of the CMY color values is less than the threshold value, monochrome the page of interest Discrimination means for discriminating the page;
And setting means for setting the threshold value referred to by the determining means when the gray compensation is instructed to be larger than when the gray compensation is not instructed.

  According to the present invention, it is possible to determine with high accuracy whether color or monochrome in order to improve the throughput of printing processing.

1 is a diagram illustrating an overall configuration of an image forming system in an embodiment. 2 is a software block diagram of the image forming apparatus in the embodiment. FIG. FIG. 2 is a block configuration diagram in a control unit of the image forming apparatus in the embodiment. 1 is an external view of an input / output device of an image forming apparatus according to an embodiment. FIG. 2 is an external view of an operation unit of the image forming apparatus according to the embodiment. FIG. 2 is a block configuration diagram in the vicinity of an operation unit and a CPU of the image forming apparatus in the embodiment. It is a data flow schematic block diagram in embodiment. It is a flowchart which shows the color determination processing procedure in embodiment.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating the overall configuration of an image forming apparatus system according to the present embodiment. The image forming apparatus 200 includes a scanner unit 2070 that is an image input device, a printer unit 2095 that is an image output device, a control unit 2000, and an operation unit 2012 that is a user interface. The scanner unit 2070, the printer unit 2095, and the operation unit 2012 are each connected to the control unit 2000, and the control unit 2000 is connected to a network transmission unit such as a LAN 2011. Further, the LAN 2011 is connected to other image forming apparatuses 220 and 230 having the same configuration as the image forming apparatus 200 and computers 101 and 102 such as a personal computer. The image forming apparatuses 220 and 230 have scanner units 2270 and 2370, printer units 2295 and 2395, and operation units 2212 and 2312, respectively, which are connected to the control units 2200 and 2300.

  FIG. 2 is a software block diagram of the image forming apparatus 200 in the present embodiment. However, the same applies to the image forming apparatuses 220 and 230.

In the figure, reference numeral 1501 denotes a UI, that is, a user interface, and is a module that mediates with the device when the operator performs various operations and settings of the image forming apparatus. This module transfers input information to various modules, which will be described later, and requests processing or sets data in accordance with the operation of the operator. Reference numeral 1502 denotes an address-book, that is, a database module that manages data transmission destinations, communication destinations, and the like. The contents of the Address-Book are used to add, delete, and acquire data by an operation from the UI 1501 and to give data sending / communication destination information to each module described later by an operator's operation.
Reference numeral 1504 denotes a universal-send, that is, a module that manages data distribution, and distributes data instructed to the operator by the UI 1501 to a similarly designated communication (output) destination. When an operator uses the scanner function of this device to instruct distribution data generation, the device is operated via the Control-API 1519 described later to generate data. Reference numeral 1505 denotes a module that is executed when a printer is designated as an output destination in the Universal-Send 1504. A module 1506 is executed when an e-mail address is designated as a communication destination in the Universal-Send 1504. A module 1507 is executed when a database is specified as an output destination in the Universal-Send 1504. A module 1508 is executed when an image forming apparatus similar to the present apparatus is designated as an output destination in the Universal-Send 1504.

  A PDL module 1509 realizes a function of printing a PDL (Page Description Language) document transmitted from the outside of the image forming apparatus by using the print function of the image forming apparatus. It also provides a function to retrieve and print an electronic document stored in an external Web server using a 1512 HTTP module.

  A Copy module 1510 uses the printer function and the scanner function of the image forming apparatus, and executes a copying operation based on a UI instruction.

  Reference numeral 1511 denotes a box module (Box) which stores a scanned image or a PDL print image in a storage device such as an HDD, prints the stored image using a printer function, transmits it using a Universal-Send function, deletes a document stored in the HDD, Provides management functions such as grouping (stored in individual BOX), movement between BOXes, and copying between BOXes.

  Reference numeral 1512 denotes a module used when the image forming apparatus communicates by HTTP, and provides communication to the PDL 1509 module described above by a TCP / IP 1516 module described later. Reference numeral 1513 denotes an lpr module which provides communication to the printer module 1505 in the above-mentioned Universal-Send 1504 by a TCP / IP 1517 module described later. Reference numeral 1514 denotes an SMTP module, which provides communication to the e-mail module 1506 in the above-mentioned Universal-Send 1504 by a TCP / IP 1517 module described later. Reference numeral 1515 denotes an SLM or Salutation-Manager module, which provides communication to the database module 1517 and the DP module 1518 in the above-mentioned Universal-Send 1504 by a TCP / IP 1517 module described later. An LPD module 1516 provides communication to the PDL 1509 module described above by a TCP / IP 1517 module described later.

  Reference numeral 1517 denotes a TCP / IP communication module that provides network communication to the various modules described above by a network driver described later. Reference numeral 1518 denotes a network driver that controls a portion physically connected to the network.

  Reference numeral 1519 denotes a Control-API that provides an interface with a lower module such as Job-Manager 1520 to be described later to upper modules such as Universal-Send 1504, PDL 1509, Copy 1510, and Box 1511. In addition, the dependency between the lower modules and the lower modules is reduced, and each diversion is enhanced.

  Reference numeral 1520 denotes a Job-Manager that interprets processing instructed from the various modules described above via the Control-API 1519 and gives instructions to the modules described below. Further, this module centrally manages hardware processing executed in the image forming apparatus.

  Reference numeral 1521 denotes a CODEC-Manager, which manages and controls various types of data compression / decompression in the process instructed by the Job-Manager 1520. Reference numeral 1522 denotes an FBE-Encoder which compresses data read by a scan process executed by the Job-Manager 1520 and the Scan-Manager 1525 in the FBE format. Reference numeral 1523 denotes a JPEG-CODEC, which performs JPEG compression of read data and JPEG expansion processing of print data in scan processing executed by the Job-Manager 1520 and Scan-Manager 1525 and print processing executed by the Print-Manager 1526. Is what you do. Reference numeral 1524 denotes an MMR-CODEC. In the scan processing executed by the Job-Manager 1520 and the Scan-Manager 1525 and the print processing executed by the Print-Manager 1526, the MMR compression of the read data and the MMR decompression of the print data are performed. The processing is performed.

  Reference numeral 1525 denotes a Scan-Manager that manages and controls scan processing instructed by the Job-Manager 1520. Reference numeral 1528 denotes a scanner I / F, which provides an I / F between the Scan-Manager 1524 and a scanner unit to which the image forming apparatus is internally connected.

  Reference numeral 1526 denotes a Print-Manager that manages and controls print processing instructed by the Job-Manager 1519. Reference numeral 1529 denotes an Engine-I / F driver that provides an interface between the Print-Manager 1526 and the printing unit.

  1527 is a PDL Interpreter, which interprets PDL or electronic document formats such as LIPS, PostScript, PCL, PDF, SVG, etc. according to the instructions of Job-Manager 1520, and uses a common expression format that does not depend on the type of PDL or electronic document format. A display list is generated.

  Reference numeral 1530 denotes a Render, which expands the display list generated by the PDL Interpreter 1527 to a raster image memory using an image processor in accordance with an instruction from the Print-Manager 1520.

  FIG. 3 is a block diagram illustrating the configuration of the image forming apparatus 200 according to the embodiment.

  The control unit 2000 is connected to a scanner 2070 as an image input device and a printer 2095 as an image output device. On the other hand, the control unit 2000 is connected to a LAN 2011 or a public line (WAN) 2051 to input / output image information and device information. It is a controller.

  In the control unit 2000, the CPU 2001 is a controller that controls the entire system. A RAM 2002 is a system work memory for operating the CPU 2002, and is also an image memory for temporarily storing image data. A ROM 2003 is a boot memory and stores a system boot program. An HDD 2004 is a hard disk drive that stores system software and image data. When the apparatus is turned on, the CPU 2002 accesses the HDD 2004 according to the boot program stored in the ROM 2003, loads the system program into the RAM 2002, and executes the processing program having the configuration shown in FIG.

  An operation unit I / F 2006 is an interface unit with an operation unit (UI) 2012 and outputs image data to be displayed on the operation unit 2012 to the operation unit 2012. Also, it plays a role of transmitting information input by the user of the system from the operation unit 2012 to the CPU 2001. A network I / F 2010 is connected to the LAN 2011 and inputs / outputs information. Since the image forming apparatus in the embodiment also functions as a network printer, print data from the host computer shown in FIG. 1 is also print data (print data written in PostScript) via this Network I / F 2010. Will be received. A Modem 2050 is connected to the public line 2051 and inputs / outputs information. The above devices are arranged on the system bus 2007. An image bus I / F 2005 is a bus bridge that connects a system bus 2007 and an image bus 2008 that transfers image data at high speed and converts a data structure.

  The image bus 2008 is configured by a PCI (Peripheral Component Interconnect) bus or IEEE1394. The following devices are arranged on the image bus 2008. An image processor (RIP) 2060 expands the display list into a raster image. A device I / F unit 2020 connects an image input / output device such as a scanner 2070 and a printer 2095 to the controller 2000, and performs synchronous / asynchronous conversion of image data. A scanner image processing unit 2080 corrects, processes, and edits input image data. A printer image processing unit 2090 performs printer correction, resolution conversion, halftoning, and the like on print output image data. The image rotation unit 2030 rotates image data. The image compression unit 2040 performs compression / decompression processing of JPEG for multi-value image data and JBIG, MMR, and MH for binary image data. A card reader I / F 2015 is an interface unit of a card reader 2016 which is a magnetic card reading device.

  The appearance of the image forming apparatus is shown in FIG. A scanner unit 2070 serving as an image input device illuminates an image on paper as a document and scans and exposes it with a CCD line sensor (not shown), thereby converting the image into raster signal data 2071 into an electrical signal. The original paper is set on the tray 2073 of the original feeder 2072, and when the apparatus user gives a reading start instruction from the operation unit 2012, the controller CPU 2001 gives an instruction to the scanner 2070 (2071), and the feeder 2072 copies the original paper one by one. Feeds and reads the original image. The printer unit 2095, which is an image output device, is a part that converts raster image data 2096 into an image on paper. The method is an electrophotographic method using a photosensitive drum or a photosensitive belt, and ink is ejected from a micro nozzle array. In addition, there is an ink jet method for printing an image directly on a sheet, but any method may be used.

  The printing operation is started by an instruction 2096 from the controller CPU 2001. The printer unit 2095 has a plurality of paper feed stages so that different paper sizes or different paper orientations can be selected, and has paper cassettes 2101, 2102, and 2103 corresponding thereto. A paper discharge tray 2111 receives paper that has been printed.

  Next, the configuration of the operation unit 2012 of the image forming apparatus 200 in the embodiment is shown in FIG.

  The LCD display unit 2013 has a touch panel sheet 2019 pasted on the LCD, displays a system operation screen and soft keys, and transmits the position information to the controller CPU 2001 when the displayed keys are pressed. A start key 2014 is used to start a document image reading operation. At the center of the start key 2014, there is a green and red two-color LED 2018, which indicates whether or not the start key 2014 is in a usable state. A stop key 2015 serves to stop an operation in operation. An ID key 2016 is used when inputting the user ID of the user. A reset key 2017 is used when initializing settings from the operation unit.

  FIG. 6 is a block configuration diagram mainly around the operation unit 2019 and the CPU 2001 of the image forming apparatus.

  In the image forming apparatus, reference numeral 2001 denotes a control CPU, which comprehensively controls access to various devices connected to the system bus 2007 based on a control ROM stored in the 2003 program ROM and the 2004 HDD. Input information is read from the scanner 2070 connected via the interface 2071, and an image signal as output information is output to the printing unit 2095 connected via the printing unit interface 2096. Reference numeral 2002 denotes a RAM that functions as a main memory, work area, and the like of the CPU of 2001. A user input is received from the touch panel 2019 and hard keys 2014-2017, and the operation content is acquired via the operation input unit I / F 20061. Based on the acquired operation content and the above-described control program, display screen data is generated in the CPU 2001, and the display screen is output to a screen output device 2013 such as an LCD or CRT via an output device controller 20062 that controls the screen output device. To do.

  Next, with reference to FIG. 7, the interpretation of the page description language (print data output from a computer on the network) and the flow of image formation will be described focusing on color processing. Here, PostScript (registered trademark) will be described as an example of the page description language.

  The interpreter 3001 is one of the PDL Interpreters 1527 in FIG. 2, and interprets data described in the PostScript language to generate a display list 3011 that is intermediate language data. The CMS engine 3004 is a module that performs color management, and generates an output color (C (cyan) M (magenta) Y (yellow) K (black)) specific to the printer engine after converting the input color to an absolute color space. It is. The PostScript language defines various color spaces such as Device color space, CIEBased color space, and special color space. For input colors specified in the Device color space, RGB source profiles, CMYK simulation profiles, etc. are prepared in advance. Color conversion is performed using the specified ICC profile group. For input colors specified in the CIEBased color space, color conversion is performed according to the conversion table, conversion function, and conversion matrix specified in the color space. Conversion from the absolute color space to the color space specific to the printer engine is performed using an output profile or a Color Rendering Dictionary defined by PostScript. Regarding the output profile, a gray compensation profile in which priority is given to expressing the gray scale in K single color and a normal profile in which the gray scale is expressed in CMYK four colors can be selectively used.

  A color determination unit 3005 examines CMYK colors, which are output values of the CMS engine, and determines whether the currently processed page is a color page or a monochrome page. A display list generator 3006 generates a display list 3011 that is intermediate language data. The display list includes an attribute flag for each object, and identifies whether the object is a graphic, an image, or a character. This attribute flag is used for subsequent image processing after rendering. The renderer 3002 interprets the display list and generates a bitmap 3012 each having a bit depth of 8 bits × 4 planes (= C, M, Y, K), and most processing is performed using the RIP 2060 of FIG. Is done.

  Also, the renderer 3002 generates an object attribute map 3013 indicating the attribute for each device pixel unit as the fifth plane based on the attribute flag included in the display list 3011. Here, the object attribute map has attribute information of bit depth 2 for each pixel. The 2-bit breakdown is, for example, a graphic “01”, an image “10”, and a character “11” in binary.

  The image processor 3003 is controlled by the Print Manager 1526 shown in FIG. 2, and performs image processing such as density / color balance adjustment 3007, output gamma correction 3008, and halftoning 3009 on the CMYK bitmap 3012 generated by the render 3002. It is. The halftoning 3009 refers to the object attribute map 3013 and applies different halftoning for each object attribute. For example, for a graphics attribute image area, a resolution-prioritized high-line-number screen is used as an image attribute (intermediate). (Tone image attribute) is applied to a low resolution screen with gradation priority, and error diffusion is applied to an image area of character attribute. It should be noted that a dither matrix that emphasizes resolution is used for graphics, and a dither matrix that emphasizes gradation is used for halftone images. In short, it is only necessary to perform processing suitable for the image area.

  If the color determination unit 3005 determines that the page is a monochrome page, only the component K bitmap of the CMYK bitmap 3012 created by the render 3002 is sent to the image processor 3003 and used in the final output. A map 3015 is generated. If the color determination unit 3005 determines that the page is a color page, the CMYK bitmap 3012 generated by the render 3002 is sent to the image processor 3002 as it is, and a CMYK bitmap 3014 used for final output is generated. The In this way, the CMYK bitmap 3014 or K bitmap 3015 generated by the image processor 3003 is transferred to the printer engine via the Engine I / F 1529 of FIG. 2 and printed out on a desired medium such as recording paper. is there.

  Next, a detailed processing procedure of the color determination unit will be described with reference to FIG.

In this apparatus, since color management processing, color determination processing, and display list generation processing are executed in order for each object, the flowchart shown in FIG. 8 is called for each object as a color determination routine.

First, starting from step S3101, it is determined in step S3114 whether the current page color determination is undecided. If it has already been determined to be color or monochrome, the color determination is not performed and the process proceeds to S3115 and ends. If not yet determined, it is determined in step S3102 whether the currently selected output profile is a gray compensation profile. If the output profile is a gray compensation profile, the process proceeds to step S3104; otherwise, the process proceeds to step S3103.

  In step S3103, the color determination threshold values Tc, Tm, and Ty are set to Tc = cLow, Tm = mLow, and Ty = yLow. If the process proceeds to step S3104, the color determination threshold values Tc, Tm, and Ty are set to Tc = cHigh, Tm = mHigh, and Ty = yHigh. In either case, the process proceeds to step S3105.

Here, the relationship is cLow, mLow, yLow, cHigh, mHigh, yHigh, all of which are relatively low concentration values in the range 0 to 255, for example, “values less than 16”.
cLow <cHigh
mLow <mHigh
yLow <yHigh
Is a constant that holds

  In other words, the reason why the threshold value in the case of the gray compensation profile is increased is that the gray compensation profile originally exists because there is a high possibility that recording in gray is intended, so color is processed by the processing described later. It is for making it difficult to be judged. In other words, if there is no gray compensation profile, it can be said that a condition that makes it easy to determine that the color is set is set. The gray compensation profile may be set in the job according to a user instruction when a print job is issued by the host computer, or may be set in advance on the operation panel of the image forming apparatus. good.

  When the process proceeds to step S3105, it is determined whether the object whose color is to be determined is an image (halftone image) attribute. If it is determined that the attribute is a halftone image attribute, the process proceeds to step S3106. Otherwise, that is, if it is determined that the object of interest is graphics or a character, the process proceeds to step S3109.

  Step S3106 constitutes loop control to be applied to all the pixels of the object of interest (halftone image area) in the process with step S3108. When the processing for all the pixels is completed, the process proceeds to step S311. During the loop control, it is determined in step S3107 whether C> Tc, M> Tm, or Y> Ty is satisfied for the color values C, M, and Y of the pixels in the image data. The process proceeds to step S3110. If No, the loop control is continued.

  If the process proceeds to step S3109, since the object of interest is graphics or characters, whether C> Tc, M> Tm, or Y> Yy holds for the color values C, M, and Y to be used. If YES, the process proceeds to step S3110. If NO, the process proceeds to step S3111.

  In step S3111, it is checked whether or not color determination has been performed on all objects in the page. If no, the process proceeds to step S3113, where the current page is determined to be undecided (during determination) and the process ends. If Yes, the process advances to step S3112 to determine that the current page is monochrome and the process ends. In step S3110, the current page is determined to be color, and the process ends.

  Note that the determination result of the color page and the monochrome page is stored as an external variable in the RAM 2002 in FIG. 3, and as described with reference to FIG. 7, only the K plane of the bitmap of the CMYK plane generated by the render 3002 is used. Or, Print Manager 1526 refers to it to determine whether to use the bitmap of each plane of CMYK.

  When it is determined that only the K plane is used, high-speed printing is performed by printing black bitmap image data using black toner or black ink. In addition, when four planes of CMYK are used, high-quality color printing is performed although it takes time compared to the K single color.

  The reason why the recording speed of the black single color is high is, for example, in the case of a laser beam printer, the photosensitive drum commonly used for each recording color component, and the toner of each recording color component in contact with the photosensitive drum. In the case of an apparatus having a developing device for holding one of them and a transfer drum for transferring a toner image generated on the photosensitive drum, one exposure is performed in the case of K single color. While image formation is completed by scanning and transferring to a transfer drum, in the case of full color, a device that performs a total of four times of scanning exposure and transfer to the transfer drum can be mentioned. In addition, in a printer structure that ejects ink droplets, a type in which the number of nozzles for black is larger than C, M, and Y is used. As a result, the width that can be recorded by a single scanning movement of the carriage becomes wider in the case of black monochrome, and the number of scanning movements can be reduced.

<Second Embodiment>
In the above embodiment (first embodiment), the threshold for color determination is switched between High and Low depending on whether the output profile is a gray compensation profile, but the color determination threshold is displayed on the operation panel. It is also possible to provide a screen for setting each CMY and perform color determination according to the value set on the screen. More detailed color determination thresholds can be adjusted, and usability is improved. The contents set by the user are stored and held in the HDD 2004, which is a non-volatile memory, and the previous setting contents are reflected unless changed. This is the second embodiment.

  As described above, according to the present embodiment, only when a CMY output value of a certain value or more is detected in one of the elements constituting the page, the page is determined to be a color, and is not detected at all. In this case, the color determination can be performed without omission by providing a determination mechanism for determining monochrome. Regardless of the discrimination result, even if a CMYK plate is created and printed using the K plate only when it is determined to be monochrome, if the CMY value for color determination is a small value, the ignored CMY value is K It has little effect on the generation of the plate and hardly affects the print quality during monochrome output. Since it is not masked with a low-level CMY value in advance, it does not affect the print quality of the highlight part of the gradation during color output. In addition, since the page interpretation method such as color processing is not changed according to the color determination result, the page interpretation and the color determination can be performed at the same time, and the processing can be performed in one pass without causing a large performance problem. Furthermore, when gray compensation is selected in the color management specification, the possibility of misjudgment can be further reduced by raising the CMY value for judging color, and the user can selectively change the judgment level. Can do.

  The present invention may be applied to a system constituted by a plurality of devices including a printer (for example, a host computer, an interface device, a scanner, a printer, etc.) or to a single printer device.

  Further, as described in the above embodiment, the image forming apparatus 200 (same for 220 and 230) of the present embodiment loads a system program stored in the HDD to the RAM 2003 and executes it at the time of startup. Obviously, the present invention also includes computer programs. In general, in order to operate a computer program, a computer-readable storage medium such as a CDROM is set in the apparatus, and can be executed by copying or installing in a system. It is clear that the medium also falls within that category. If the image forming apparatus 200 is not provided with means for reading data from such a computer-readable storage medium (for example, a CDROM drive), it is read by the same means included in the host computer, transferred to the image forming apparatus 200, and a program. It would be good to make it update.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running 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.

  Further, after the program code read from the storage medium is written in a memory provided in a function expansion card 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 card 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.

  Therefore, if the embodiment concerning this invention is enumerated, it will become as follows.

[Embodiment 1] Generation means for generating bitmap image data of each recording color component based on print data described in a page description language, and a color image on a predetermined recording medium based on the generated bitmap image data A method for controlling an image forming apparatus that prints the image using a printing unit,
For each object described in the page description language, a search step for sequentially searching whether or not the data regarding the recording color component exceeds a predetermined threshold value;
A first determination step in which, when it is determined that there is an object having a recording color component exceeding the threshold during the search process by the search step, the subsequent search is stopped and the page of interest is determined to be a color page;
A second determination step of determining that the page of interest is a monochrome page when all objects are equal to or less than the color component equal to or less than the threshold value by the search process in the search step;
If it is determined in the first determination step that the page is a color page, the printing unit prints based on the bitmap image data of each recording color component generated by the generation unit, and the second determination unit And a control step of printing by the printing unit using only the black bitmap image data generated by the generating unit when the page is determined to be a monochrome page. Control method.

    [Embodiment 2] The object has halftone image, graphics, and character types, and the search means sets the pixel-based color for the halftone image and the drawing color for the graphics and the character. The method of controlling an image forming apparatus according to the first embodiment, wherein it is determined whether or not a threshold value is exceeded.

[Embodiment 3] Further, a determination step of determining whether or not color management for performing gray compensation is specified in a print job;
The method for controlling an image forming apparatus according to claim 1, further comprising: setting the threshold value according to the determination step.

    [Embodiment 4] The threshold value when it is determined in the determination step that color management for gray compensation is specified is a threshold value larger than the threshold value when there is no gray management. A method for controlling an image forming apparatus.

    [Embodiment 5] The method for controlling an image forming apparatus according to Embodiment 1 or 2, further comprising a step of setting the threshold value by an input from a predetermined operation unit.

    [Embodiment 6] The image processing apparatus further includes a color management process for converting a color space represented by the print data into a color space included in the printing unit, and the search process is performed on a conversion result obtained in the color management process. The method of controlling an image forming apparatus according to any one of Embodiments 1 to 5, wherein the method is performed as described above.

[Embodiment 7] Generation means for generating bitmap image data of each recording color component based on print data described in a page description language, and a color image on a predetermined recording medium based on the generated bitmap image data An image forming apparatus that prints the image using a printing unit,
Search means for sequentially searching whether or not the data relating to the recording color component exceeds a predetermined threshold for each object described in the page description language;
A first determination unit that, during the search process by the search unit, determines that there is an object having a recording color component that exceeds the threshold value, stops the subsequent search, and determines that the page of interest is a color page;
A second determination unit that determines that the page of interest is a monochrome page when all the objects are equal to or less than the threshold color component by the search process by the search unit;
When the first determination unit determines that the page is a color page, the printing unit prints based on the bitmap image data of each recording color component generated by the generation unit, and the second determination unit An image forming apparatus comprising: a control unit that causes the printing unit to print using only the black bitmap image data generated by the generation unit when it is determined that the page is a monochrome page.

[Embodiment 8] Generation means for generating bitmap image data of each recording color component based on print data described in a page description language, and a color image on a predetermined recording medium based on the generated bitmap image data A computer program that functions as an image forming apparatus that prints the image using a printing unit,
Search means for sequentially searching whether or not the data relating to the recording color component exceeds a predetermined threshold for each object described in the page description language;
A first determination unit that, during the search process by the search unit, determines that there is an object having a recording color component that exceeds the threshold value, stops the subsequent search, and determines that the page of interest is a color page;
A second determination unit that determines that the page of interest is a monochrome page when all the objects are equal to or less than the threshold color component by the search process by the search unit;
When the first determination unit determines that the page is a color page, the printing unit prints based on the bitmap image data of each recording color component generated by the generation unit, and the second determination unit When it is determined that the page is a monochrome page, the image forming unit functions as a control unit that causes the printing unit to print using only the black bitmap image data generated by the generating unit. Computer program for equipment.

    [Embodiment 9] A computer-readable storage medium storing the computer program according to Embodiment 8.

  In the above embodiment, the configuration according to Embodiments 2 to 6 may be added to the image forming apparatus, the computer program, and the computer readable storage medium.

Claims (11)

An image output device that generates and prints bitmap data of a page represented by CMYK which is a recording color component according to print data of a page description language,
Is greater than any one of the threshold color values of CMY represented by the print data, the page of interest to determine the color page, if all of the CMY color values is less than the threshold value, monochrome the page of interest Discrimination means for discriminating the page;
An image output apparatus comprising: a setting unit configured to set the threshold referred to by the determination unit to be larger when gray compensation is instructed than when the gray compensation is not instructed. An image output device that generates and prints bitmap data of a page represented by CMYK which is a recording color component according to print data of a page description language,
When any one of the CMY color values among the pages represented by the print data is larger than a threshold value, the page is determined as a color page, and when all the CMY color values are equal to or smaller than the threshold value, Discrimination means for discriminating the page as a monochrome page;
Setting means for setting the threshold value referred to by the determination means when gray compensation is instructed to be larger than when the gray compensation is not instructed;
An image output apparatus comprising: An image output device that generates and prints bitmap data of a page represented by CMYK which is a recording color component according to print data of a page description language,
When any one of the CMY color values of the CMYK is larger than the threshold value, the page of interest is determined to be a color page, and when all of the CMY color values are equal to or smaller than the threshold value, the page of interest is a monochrome page. Discriminating means for discriminating;
Setting means for setting the threshold value referred to by the determination means when gray compensation is instructed to be larger than when the gray compensation is not instructed;
An image output apparatus comprising: Discrimination result of the discriminating means, to indicate that a color page, print using bitmap data of each recording color components represented by CMYK,
Discrimination result of the discriminating means, to indicate that a mode Nokuropeji, images according to any one of claims 1 to 3, characterized in that print using only the bit map data of color components K Output device. An interpreter that converts an input color represented by print data in the page description language into an absolute color space, and generates intermediate language data representing the color of the absolute color space representing CMYK of a specific recording color component related to printing of the apparatus Means,
Rendering means for generating bitmap image data of each recording color component CMYK according to the intermediate language data obtained by the interpreter means,
The discriminating means, based on the CMY value of the intermediate language data, an image output device according to any one of claims 1 to 4, characterized in that to determine color page or monochrome page. A method for controlling an image output apparatus that generates and prints bitmap data of a page represented by CMYK as recording color components in accordance with print data of a page description language,
Is greater than any one of the threshold color values of CMY represented by the print data, the page of interest to determine the color page, if all of the CMY color values is less than the threshold value, monochrome the page of interest A discrimination process for discriminating a page,
A control method for an image output apparatus, comprising: a setting step of setting the threshold value referred to by the determination step to be larger when gray compensation is instructed than when the gray compensation is not instructed. A method for controlling an image output apparatus that generates and prints bitmap data of a page represented by CMYK as recording color components in accordance with print data of a page description language,
When any one of the CMY color values among the pages represented by the print data is larger than a threshold value, the page is determined as a color page, and when all the CMY color values are equal to or smaller than the threshold value, A discriminating step for discriminating the page as a monochrome page;
A setting step for setting the threshold value referred to by the determination step when gray compensation is instructed to be larger than when the gray compensation is not instructed;
A method for controlling an image output apparatus, comprising: A method for controlling an image output apparatus that generates and prints bitmap data of a page represented by CMYK as recording color components in accordance with print data of a page description language,
When any one of the CMY color values of the CMYK is larger than the threshold value, the page of interest is determined to be a color page, and when all of the CMY color values are equal to or smaller than the threshold value, the page of interest is a monochrome page. A discriminating step for discriminating;
A setting step for setting the threshold value referred to by the determination step when gray compensation is instructed to be larger than when the gray compensation is not instructed;
A method for controlling an image output apparatus, comprising: The determination judgment result of step, indicating that it is a color page, print using bitmap data of each recording color components represented by CMYK,
The determination step to take determination result, mode to indicate that a Nokuropeji, according to any one of claims 6 to 8, characterized in that print using only the bit map data of color components K A method for controlling an image output apparatus. An interpreter that converts an input color represented by print data in the page description language into an absolute color space, and generates intermediate language data representing the color of the absolute color space representing CMYK of a specific recording color component related to printing of the apparatus Process,
A rendering process for generating bitmap image data of each recording color component CMYK according to the intermediate language data obtained in the interpreter process,
Wherein in the determination step, based on the CMY value of the intermediate language data, the control method for an image output apparatus according to any one of claims 6 to 9, characterized in that to determine color page or monochrome page .   A computer program for causing a computer to execute the steps of the method according to any one of claims 6 to 10.

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