JP2004082488A - Print controller, printing method, program, and computer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the quality of a print image at low resolutions. <P>SOLUTION: In the print controller capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on an object to be printed based on the print data, the print data is acquired by converting image data having a resolution higher than the print data. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing control device, a printing method, a program, and a computer system. In particular, the present invention relates to a print control device capable of forming dots on a printing medium based on print data, a printing method of the print control device, a program for controlling the print control device, and a print control device. And a computer system having the same.
[0002]
[Background Art]
In a print control apparatus that prints an image by forming dots on a printing medium (paper, cloth, film, or the like), the type of the printing medium for printing an image, an output instruction of an application program for executing printing, and the like. , One of the resolutions prepared in advance (low resolution to high resolution) is appropriately selected, and the image is printed on the printing medium at the selected resolution.
[0003]
[Problems to be solved by the invention]
As the resolution at the time of printing an image shifts from a high resolution to a low resolution, the size of a dot on which an image is formed increases. When printing a low-resolution image on a printing medium, since the low-resolution image is printed using dots having a certain size, the outline of the printed image is not smooth, and the quality of the printed image is degraded. Could be done.
Therefore, an object of the present invention is to improve the quality of an image at a low resolution.
[0004]
[Means for Solving the Problems]
A main invention for achieving the above object is a print control device which converts image data into print data for forming dots of a plurality of sizes, and is capable of forming dots on a printing medium based on the print data. The printing apparatus is characterized in that the print data is obtained by converting the image data having a higher resolution than the print data.
Other objects and features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
=== Disclosure Overview ===
At least the following matters will be made clear by the description in the present specification and the accompanying drawings.
A print control device capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on a printing medium based on the print data, wherein the print data is the print data. Wherein the image data having a higher resolution than the image data is converted.
According to the print control apparatus, print data for forming dots of a plurality of sizes can be obtained by converting image data having a higher resolution than the resolution of the print data. Can be improved.
[0006]
In the print control device, the image data may be data supplied to a driver for converting the image data into the print data.
According to the print control device, since the image data has a resolution higher than the resolution of the print data before the image data is converted into the print data, the quality of the print image at a low resolution is improved by using the image data. be able to.
[0007]
Further, in such a print control device, the image data may be color-converted into CMYK color system data and then converted into the print data.
According to the print control apparatus, it is possible to improve the quality of a print image at a low resolution by using data obtained by performing color conversion of image data into a CMYK color system.
[0008]
In the print control device, the image data may be converted into the print data after the pixel data is formed into pixel data in a form in which each pixel corresponds to the necessity of forming a dot.
According to the printing control device, it is possible to improve the quality of a low-resolution printed image by using pixel data in which each pixel corresponds to the necessity of dot formation.
[0009]
Further, in such a print control device, a plurality of pixels in the pixel data and a single pixel in the print data are respectively associated with each other, and the pixel data is set in accordance with the number of pixels that need to form dots in the plurality of pixels. Alternatively, the print data may be converted into the print data for forming any one of a plurality of sizes of dots in the single pixel.
According to the printing control device, according to the number of pixels for forming a dot in a plurality of pixels, by obtaining print data for forming any of a plurality of sizes of dots in a single pixel, The quality of a print image at a low resolution can be improved.
[0010]
In the print control device, a plurality of pixels in the pixel data and a single pixel in the print data are respectively associated with each other, and the pixel data includes a predetermined number of pixels for which dots need to be formed in the plurality of pixels. In the above, a first dot of a predetermined size is formed in the single pixel, and when the number of pixels requiring dot formation in the plurality of pixels is less than a predetermined number, the first dot is formed in the single pixel. It may be converted to the print data for forming a second dot smaller than a dot.
According to the print control device, obtaining print data for forming a first dot or a second dot having different sizes in a single pixel according to the number of pixels for forming a dot in a plurality of pixels. Thereby, the quality of a print image at a low resolution can be improved.
[0011]
Further, in the print control device, a plurality of pixels in the pixel data and a single pixel in the print data are respectively associated with each other, and the pixel data has a predetermined number of pixels for which dots need to be formed in the plurality of pixels. When the number is less than the number, the print data may be converted into the print data for forming the second dot at a predetermined position of the single pixel according to a pixel position that requires dot formation in the plurality of pixels. Good.
According to the print control device, when the number of pixels for forming dots in a plurality of pixels is less than a predetermined number and at a predetermined position, print data for forming a second dot at a predetermined position of a single pixel is obtained. Thereby, the quality of the print image at a low resolution can be improved.
[0012]
Further, in such a print control device, a plurality of pixels in the pixel data and a single pixel in the print data are respectively associated with each other, and the pixel data has a smaller number of pixels than the plurality in a unit of a plurality of pixel columns in a predetermined direction. Are converted into columns, and then a plurality of large pixels are arranged at predetermined positions of the single pixel in accordance with the number of pixels and the pixel positions that need to form dots in a plurality of adjacent pixels out of the plurality of pixel columns. May be converted into the print data for forming any of the dots.
According to the printing control apparatus, first, a plurality of pixel rows in a predetermined direction in the pixel data are respectively converted into a number of pixel rows smaller than the plurality of pixel rows. In accordance with the number of pixels and the pixel position that require dot formation within a pixel, by obtaining print data for forming any of a plurality of sizes of dots at a predetermined position of a single pixel, low resolution is obtained. Can improve the quality of the print image.
[0013]
In this print control device, a plurality of pixels in the pixel data and a single pixel in the print data are associated with each other, and the pixel data needs to form dots in a block in units of the plurality of pixels. The print data may be converted into the print data for forming any one of a plurality of sizes of dots at a predetermined position of the single pixel according to the number of pixels and the pixel position.
According to the printing control device, any one of a plurality of sizes of dots is determined at a predetermined position of a single pixel in accordance with the number of pixels and the pixel position in which a dot is required to be formed in a block having the plurality of pixels as a unit. By efficiently obtaining print data for forming the image, the quality of a print image at a low resolution can be improved.
[0014]
Further, in such a print control device, a plurality of pixels in the pixel data are associated with a single pixel in the print data, and the image data of the plurality of pixels is converted into the print data by a computer, and the converted The print data may be supplied to a printing device.
According to the printing control device, the image data of a plurality of pixels is converted into printing data by a computer, and the converted printing data is supplied to the printing device. Therefore, the transfer time of the printing data from the computer to the printing device is reduced. It is possible to improve the quality of a print image at a low resolution without shortening the throughput and reducing the throughput.
[0015]
Further, in such a print control device, a transporting unit for transporting the printing medium in the sub-scanning direction, and moving the ink in a main scanning direction that intersects the sub-scanning direction to eject ink to the printing medium. A print head for performing printing.
According to the printing control device, the quality of a print image at low resolution is improved by using a device having a conveyance unit for conveying a printing medium and a print head for performing printing on the printing medium. be able to.
[0016]
A print control device capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on a printing medium based on the print data, wherein the print data is the print data. The image data having a resolution higher than the resolution of the image data is supplied to driver means for converting the image data into the print data, and the image data is converted into CMYK color system data. After being subjected to color conversion and further halftone processing, each pixel and the necessity of dot formation are converted into corresponding pixel data, then converted into the print data, and a plurality of pixels in the pixel data and the print data are converted. Each pixel is associated with a single pixel in the data, and the pixel data has a predetermined number or more of pixels that need to form dots in the plurality of pixels. When forming a first dot of a predetermined size in the single pixel, when the number of pixels that require dot formation in the plurality of pixels is less than a predetermined number, the single pixel is more than the first dot Converted to the print data for forming a small second dot, the plurality of pixels in the pixel data and the single pixel in the print data respectively correspond, the pixel data, the formation of dots in the plurality of pixels When the required number of pixels is less than a predetermined number, the print data for forming the second dot at a predetermined position of the single pixel according to a pixel position where a dot needs to be formed within the plurality of pixels. Is converted into a plurality of pixels in the pixel data and a single pixel in the print data, respectively, and the pixel data is more than the plurality of pixels in units of a plurality of pixel columns in a predetermined direction. The predetermined number of pixel rows are converted to a predetermined number of pixel rows, and then the predetermined position of the single pixel is determined in accordance with the number of pixels and the pixel positions in the plurality of adjacent pixel rows that need to form dots in the smaller number of pixel rows. Is converted into the print data for forming the first dot or the second dot, the plurality of pixels in the pixel data and a single pixel in the print data respectively correspond, the image data of the plurality of pixels, the computer The print data is converted to the print data, and the converted print data is supplied to a printing apparatus, and a conveying unit for conveying the printing medium in the sub-scanning direction, and a main scanning direction intersecting the sub-scanning direction. A print head for performing printing on the printing medium by moving and ejecting the ink.
[0017]
A printing method for a printing apparatus capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on a printing medium based on the print data, wherein the print data is A printing method characterized by converting the image data having a resolution higher than the resolution of the print data.
According to the printing method, the quality of a print image at a low resolution can be improved.
[0018]
A print control device capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on a printing medium based on the print data has a higher resolution than the print data. A program for implementing a function of converting image data to obtain the print data.
According to the program, it is possible to realize control for improving the quality of a print image at a low resolution.
[0019]
A print control device capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on a printing medium based on the print data; a computer main body connected to the print device; , Wherein the print data is obtained by converting the image data having a resolution higher than the resolution of the print data.
[0020]
=== Computer system configuration example ===
FIG. 1 is a block diagram illustrating a configuration example of a computer system having a print control device according to the present invention. In FIG. 1, a color inkjet printer 2 as a printing device is a printing device, and a color inkjet printer 2, a computer 4, a display device (such as a CRT 21 or an LCD (not shown)), and an input device (a keyboard (not shown)). , A mouse, etc.) and a drive device (such as a flexible drive device or a CD-ROM drive device, not shown) constitute a computer system. In the present embodiment, a print control device includes the color inkjet printer 2 and the printer driver 10 in the computer 4. In this case, a printer in which the printer driver 10 is loaded into the color inkjet printer 2 may be used as the print control device.
[0021]
The computer 4 includes a video driver 8 for driving the display of the CRT 6, a printer driver 10 as a driver for printing and driving the color inkjet printer 2, and a drive for controlling the video driver 8 and the printer driver 10. And an application program 12. The video driver 8 appropriately processes image data to be processed in accordance with a display command from the application program 12, and then supplies the processed image data to the CRT 6. The CRT 6 displays an image according to the image data supplied from the video driver 8. The printer driver 10 appropriately processes image data to be processed according to a print command from the application program 12, and then supplies the image data to the color inkjet printer 2 as print data PD. The operations of the video driver 8, the printer driver 10, and the application program 12 are controlled by an operating system OS (not shown) prepared in the computer 4.
[0022]
<Configuration Example of Printer Driver 10>
The printer driver 10 includes a resolution conversion module 14, a color conversion module 16, a halftone module 18, a dither table 20, an error memory 22, a gamma table 24, a resolution multi-value conversion module 26, a rasterizer 28, It comprises a user interface display module 30, a UI printer interface module 32, and a color conversion look-up table LUT.
[0023]
The resolution conversion module 14 converts image data (character data of an outline font, illustration data, etc.) specified by a user output from the application program 12 into color image data having a higher resolution than that used when printing on a printing medium. Is what you do. For example, when the resolution for printing an image on a printing medium is specified as 360 × 360 dpi, the above character data, illustration data, and the like are converted to 720 × 720 dpi color image data. Note that the color image data converted by the resolution conversion module 14 is RGB color system data including color components of three primary colors of RGB.
[0024]
The color conversion look-up table LUT associates the conversion relationship between the RGB color system data output from the resolution conversion module 14 and the CMYK color system data. The color conversion module 16 refers to the color conversion look-up table LUT to convert the RGB color image data output from the resolution conversion module 14 into a plurality of ink colors that can be used by the color inkjet printer 2 on a pixel-by-pixel basis. Is converted to multi-tone data. The multi-gradation data converted by the color conversion module 16 has, for example, 256 gradation values.
[0025]
The halftone module 18 refers to a dither table 20 for performing a dither method, a gamma table 24 for performing γ correction, and an error memory 22 for storing a diffused error when performing an error diffusion method. For example, halftone processing is performed on multi-tone data output from the color conversion module 16 to generate halftone image data as pixel data. The CMYK halftone image data has the same resolution (for example, 720 × 720 dpi) as the RGB color image data output from the resolution conversion module 14. Further, the halftone image data is binary data of a logical value “1” when displaying a dot and a logical value “0” when not displaying a dot in each pixel unit.
[0026]
The resolution multi-level conversion module 26 converts the binary half-tone image data obtained from the half-tone module 18 into multi-level half-tone image data having a resolution at the time of printing an image on a printing medium. . The resolution of binary halftone image data (for example, 720 × 720 dpi) is higher than the resolution of multivalued halftone image data (for example, 360 × 360 dpi). The details of the resolution multi-level conversion module 26 will be described later.
[0027]
The rasterizer 28 arranges multi-valued halftone image data obtained from the resolution multi-value conversion module 26 in order of data to be supplied to the color inkjet printer 2, and supplies the data as print data PD to the color inkjet printer 2. The print data PD includes raster data indicating a dot formation state when the print head moves in the main scanning direction, and a transport amount for the printing medium to sequentially move in the sub-scanning direction that intersects with the main scanning direction. And data shown.
[0028]
The user interface display module 30 has a function of displaying various windows related to printing and a function of receiving an input instruction from a user in these windows.
[0029]
The UI printer interface module 32 is interposed between the user interface display module 30 and the color inkjet printer 2, and performs a bidirectional interface. That is, when the user instructs the user interface display module 30, the UI printer interface module 32 provides an interface for supplying various commands COM obtained by decoding commands from the user interface display module 30 to the color inkjet printer 2. Do. On the other hand, the UI printer interface module 32 also provides an interface for supplying various commands COM from the color inkjet printer 2 to the user interface display module 30.
[0030]
As described above, the printer driver 10 realizes the function of supplying the print data PD to the color inkjet printer 2 and the function of inputting and outputting various commands COM to and from the color inkjet printer 2. Note that a program for realizing the function of the printer driver 10 has a code such as a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punch card, and a bar code as a computer-readable recording medium. The information is supplied to the computer 4 in a state of being recorded on various media such as a printed matter, an internal storage device of the computer, and an external storage device. In addition, a program for realizing the function of the printer driver 10 may be downloaded to the computer 4 from a WWW (World Wide Web) server or the like published on the Internet.
[0031]
=== Configuration Example of Printing Apparatus (Inkjet Printer) ===
<Configuration example of color inkjet printer>
With reference to FIGS. 2, 3, 4, and 5, an outline of the printing apparatus will be described using a color inkjet printer as an example. FIG. 2 is a diagram for explaining the overall configuration of the color inkjet printer of the present embodiment. FIG. 3 is a schematic diagram for explaining the periphery of the carriage of the color inkjet printer of the present embodiment. FIG. 4 is a diagram for explaining the vicinity of the transport unit of the inkjet printer according to the present embodiment. FIG. 5 is a perspective view for explaining the periphery of the transport unit of the inkjet printer according to the present embodiment.
The ink jet printer according to the present embodiment includes a paper transport unit 100, an ink discharge unit 200, a cleaning unit 300, a carriage unit 400, a group of measuring instruments 500, and a control unit 600.
[0032]
The paper transport unit 100 feeds a printing medium, for example, paper S, to a printable position, and moves a predetermined moving amount in a predetermined direction (a direction perpendicular to the paper surface in FIG. 2 (hereinafter, referred to as a sub-scanning direction)) during printing. Is used to move the paper S. That is, the paper transport unit 100 functions as a transport mechanism that transports the paper S. The paper transport unit 100 includes a paper insertion slot 102A and a roll paper insertion slot 102B, a paper feed motor (not shown), a paper feed roller 104, a platen 106, a paper feed motor (hereinafter, referred to as a PF motor) 108, It has a paper feed motor driver (hereinafter, referred to as a PF motor driver) 110, a paper feed roller 112A, a paper discharge roller 112B, a free roller 114A, and a free roller 114B. However, in order for the paper transport unit 100 to function as a transport mechanism, not all of these components are necessarily required.
[0033]
The paper insertion opening 102A is where the paper S, which is a printing medium, is inserted. The paper feed motor (not shown) is a motor that transports the paper S inserted into the paper insertion slot 102A into the printer, and is configured by a pulse motor. The paper feed roller 104 is a roller that automatically conveys the paper S inserted into the paper insertion slot 102A into the printer, and is driven by a paper feed motor. The paper feed roller 104 has a substantially D-shaped cross-sectional shape. Since the circumference of the circumferential portion of the paper feed roller 104 is set longer than the transport distance to the PF motor 108, the printing medium can be transported to the PF motor 108 using the circumferential portion. Note that the rotational driving force of the paper feed roller 104 and the frictional resistance of the separation pad (not shown) prevent a plurality of print media from being fed at once.
[0034]
The platen 106 supports the paper S during printing. The PF motor 108 is a motor that feeds, for example, the paper S, which is a printing medium, in the paper transport direction, and is configured by a DC motor. The PF motor driver 110 is for driving the PF motor 108. The paper feed roller 112A is a roller that feeds the paper S conveyed into the printer by the paper feed roller 104 to a printable area, and is driven by the PF motor 108. The free roller 114A is provided at a position facing the paper feed roller 112A, and presses the paper S toward the paper feed roller 112A by sandwiching the paper S with the paper feed roller 112A.
[0035]
The paper discharge roller 112B is a roller that discharges the paper S on which printing has been completed to the outside of the printer. The paper discharge roller 112B is driven by a PF motor 108 by a gear (not shown). The free roller 114B is provided at a position facing the paper discharge roller 112B, and presses the paper S toward the paper discharge roller 112B by sandwiching the paper S between the paper discharge roller 112B.
[0036]
The ink discharge unit 200 is for discharging ink onto a printing medium, for example, paper S. The ink discharge unit 200 includes a head 202 and a head driver 204. The head 202 has a plurality of nozzles serving as ink discharge units, and discharges ink intermittently from each nozzle. The head driver 204 drives the head 202 and causes the head to eject ink intermittently.
[0037]
The cleaning unit 300 is for preventing the nozzles of the head 202 from being clogged. The cleaning unit 300 has a pump device 302 and a capping device 304. The pump device 302 sucks ink from the nozzles to prevent clogging of the nozzles of the head 202, and has a pump motor 306 and a pump motor driver 308. The pump motor 306 sucks ink from the nozzles of the head 202. The pump motor driver 308 drives the pump motor 306. The capping device 304 seals the nozzles of the head 202 when printing is not performed (during standby) in order to prevent the nozzles of the head 202 from being clogged.
[0038]
The carriage unit 400 is for scanning and moving the head 202 in a predetermined direction (in FIG. 1, a horizontal direction on the paper (hereinafter, referred to as a main scanning direction)). The carriage unit 400 includes a carriage 402, a carriage motor (hereinafter, referred to as a CR motor) 404, a carriage motor driver (hereinafter, referred to as a CR motor driver) 406, a pulley 408, a timing belt 410, and a guide rail 412. . The carriage 402 is movable in the main scanning direction and fixes the head 202 (therefore, the nozzles of the head 202 eject ink intermittently while moving along the main scanning direction). The carriage 402 detachably holds an ink cartridge 414 that stores ink. The CR motor 404 is a motor that moves the carriage 402 in the main scanning direction, and includes a DC motor. The CR motor driver 406 is for driving the CR motor 404. The pulley 408 is attached to a rotation shaft of the CR motor 404. The timing belt 410 is driven by a pulley 408. The guide rail 412 guides the carriage 402 in the main scanning direction.
[0039]
The measuring instrument group 500 includes a linear encoder 502, a rotary encoder 504, a paper detection sensor 506, and a paper width sensor 508. The linear encoder 502 is for detecting the position of the carriage 402. The rotary encoder 504 is for detecting the rotation amount of the paper feed roller 112A. The configuration and the like of the encoder will be described later. The paper detection sensor 506 is for detecting the position of the leading end of the paper S to be printed. The paper detection sensor 506 is provided at a position where the position of the leading end of the paper S can be detected while the paper supply roller 104 is transporting the paper S toward the paper feed roller 112A. The paper detection sensor 506 is a mechanical sensor that detects the leading end of the paper S by a mechanical mechanism. More specifically, the paper detection sensor 506 has a lever rotatable in the paper transport direction, and this lever is disposed so as to protrude into the paper S transport path. Therefore, the leading end of the paper S comes into contact with the lever and the lever is rotated, so that the paper detection sensor 506 detects the position of the leading end of the paper S by detecting the movement of the lever. The paper width sensor 508 is attached to the carriage 402. The paper width sensor 508 is an optical sensor having a light emitting unit 510 and a light receiving unit 512, and detects the presence or absence of the paper S at the position of the paper width sensor 508 by detecting light reflected by the paper S. The paper width sensor 508 detects the position of the end of the paper S while moving by the carriage 402, and detects the width of the paper S. The paper width sensor 508 can detect the leading end of the paper S based on the position of the carriage 402. Since the paper width sensor 508 is an optical sensor, the position detection accuracy is higher than that of the paper detection sensor 506.
[0040]
The control unit 600 is for controlling the printer. The control unit 600 has a CPU 602, a timer IC 604, an interface unit 606, an ASIC 608, a memory 610, and a DC controller 612. The CPU 602 controls the entire printer, and gives control commands to the DC controller 612, the PF motor driver 110, the CR motor driver 406, the pump motor driver 308, and the head driver 204. The timer IC 604 periodically generates an interrupt signal for the CPU 602. The interface unit 606 transmits and receives the print data PD, various commands COM, and the like to and from the computer 4 shown in FIG. 1 provided outside the printer. The ASIC 608 controls printing resolution, head drive waveforms, and the like, based on print information sent from the computer 4 via the interface unit 606. The memory 610 is for securing an area for storing programs of the ASIC 608 and the CPU 602, a work area, and the like, and has storage means such as a PROM, a RAM, and an EEPROM. The DC controller 612 controls the PF motor driver 110 and the CR motor driver 406 based on the control command sent from the CPU 602 and the output from the measuring instrument group 500.
[0041]
<About the configuration of the encoder>
FIG. 6 is an explanatory diagram of the linear encoder 502.
The linear encoder 502 is for detecting the position of the carriage 402, and has a linear scale 532 and a detection unit 534.
The linear scale 532 is provided with slits at predetermined intervals (for example, 1/180 inch (1 inch = 2.54 cm)), and is fixed to the printer body.
The detection unit 534 is provided to face the linear scale 532, and is provided on the carriage 402 side. The detection unit 534 includes a light-emitting diode 534A, a collimator lens 534B, and a detection processing unit 534C. The detection processing unit 534C includes a plurality (for example, four) of photodiodes 534D, a signal processing circuit 534E, And two comparators 534Fa and 534Fb.
[0042]
The light emitting diode 534A emits light when the voltage Vcc is applied through the resistors at both ends, and the light is incident on the collimator lens. The collimator lens 534B converts the light emitted from the light-emitting diode 534A into parallel light and irradiates the linear scale 532 with parallel light. The parallel light that has passed through the slit provided in the linear scale 532 passes through a fixed slit (not shown) and enters each photodiode 534D. The photodiode 534D converts incident light into an electric signal. The electric signals output from the photodiodes 534D are compared in comparators 534Fa and 534Fb, and the comparison result is output as a pulse. Then, the pulses ENC-A and ENC-B output from the comparators 534Fa and 534Fb are output from the linear encoder 502.
[0043]
FIG. 7 is a timing chart showing waveforms of two types of output signals of the linear encoder 502. FIG. 7A is a timing chart of the waveform of the output signal when the CR motor 404 is rotating forward. FIG. 7B is a timing chart of the waveform of the output signal when the CR motor 404 is reversed.
[0044]
As shown in FIGS. 7A and 7B, the phase of the pulse ENC-A and the phase of the pulse ENC-B are shifted by 90 degrees in both cases of the forward rotation and the reverse rotation of the CR motor 404. When the CR motor 404 is rotating forward, that is, when the carriage 402 is moving in the main scanning direction, as shown in FIG. 7A, the phase of the pulse ENC-A is 90 degrees smaller than that of the pulse ENC-B. I'm advancing. On the other hand, when the CR motor 404 is reversed, as shown in FIG. 7B, the phase of the pulse ENC-A is delayed by 90 degrees from the phase of the pulse ENC-B. One cycle T of each pulse is equal to the time during which the carriage 402 moves through the slit interval of the linear scale 532 (for example, 1/180 inch (1 inch = 2.54 cm)).
[0045]
The position of the carriage 402 is detected as follows. First, a rising edge or a falling edge of the pulse ENC-A or ENC-B is detected, and the number of detected edges is counted. The position of the carriage 402 is calculated based on the counted number. When one edge is detected when the CR motor 404 is rotating forward, “+1” is added to the count number, and when one edge is detected when the CR motor 404 is inverted, “−” is added. 1 ”is added. Since the period of the pulse ENC is equal to the slit interval of the linear scale 532, the amount of movement from the position of the carriage 402 when the count number is "0" can be obtained by multiplying the count number by the slit interval. That is, the resolution of the linear encoder 502 in this case is the slit interval of the linear scale 532. Further, the position of the carriage 402 may be detected using both the pulse ENC-A and the pulse ENC-B. Since the period of each of the pulses ENC-A and ENC-B is equal to the slit interval of the linear scale 532, and the phases of the pulses ENC-A and ENC-B are shifted by 90 degrees, the rising edge of each pulse When the number of detected edges is counted, the count number “1” corresponds to １ ／ of the slit interval of the linear scale 532. Therefore, if the count number is multiplied by １ ／ of the slit interval, the movement amount can be obtained from the position of the carriage 402 when the count number is “0”. That is, the resolution of the linear encoder 502 in this case is １ ／ of the slit interval of the linear scale 532.
[0046]
The detection of the speed Vc of the carriage 402 is performed as follows. First, a rising edge or a falling edge of the pulse ENC-A or ENC-B is detected. On the other hand, the time interval between the edges of the pulse is counted by a timer counter. A period T (T = T1, T2,...) Is obtained from this count value. If the slit interval of the linear scale 532 is λ, the carriage speed can be sequentially obtained as λ / T. Further, the speed of the carriage 402 may be detected using both the pulse ENC-A and the pulse ENC-B. By detecting the rising edge and the falling edge of each pulse, the time interval between edges corresponding to １ ／ of the slit interval of the linear scale 532 is counted by a timer counter. A period T (T = T1, T2,...) Is obtained from this count value. Then, assuming that the slit interval of the linear scale 532 is λ, the carriage speed Vc can be sequentially obtained as Vc = λ / (4T).
[0047]
Note that the rotary encoder 504 uses a rotating disk 552 that rotates in accordance with the rotation of the paper feed roller 112A instead of the linear scale 532 provided on the printer main body side, and a detecting unit provided on the carriage 402. The other configuration is almost the same as that of the linear encoder 502 except that the detection unit 554 provided on the printer main body side is used instead of 534 (see FIG. 5).
[0048]
=== Example of nozzle arrangement of head ===
FIG. 8 is a diagram for explaining the arrangement of nozzles on the lower surface of the head 202. On the lower surface of the head 202, a black nozzle row K, a yellow nozzle row Y, a magenta nozzle row M, and a cyan nozzle row C as color nozzle rows are formed.
[0049]
The black nozzle row K has 180 nozzles # 1 to # 180 (open circles). The 180 nozzles # 1 to # 180 (white circles) are aligned at regular intervals (nozzle pitch kD) in a straight line along the sub-scanning direction shown in FIG. The yellow nozzle row Y has 60 nozzles # 1 to # 60 (white triangles), the magenta nozzle row M has 60 nozzles # 1 to # 60 (white squares), and the cyan nozzle row C Has 60 nozzles # 1 to # 60 (white rhombus). The 180 nozzles # 1 to # 60 (white triangle, white square, and white rhombus) are aligned at regular intervals (nozzle pitch kD) along the sub-scanning direction shown in FIG. I have. Here, D is the minimum dot pitch in the sub-scanning direction (that is, the interval of the dots formed on the printing paper P at the highest resolution). For example, if the resolution is 1440 dpi, 1/1440 inch (about 17.4 inches). 65 μm). K is an integer of 1 or more.
[0050]
For example, each nozzle is provided with a piezo element (not shown) as a drive element for driving each nozzle to eject ink droplets. However, it is not limited to a piezo element. A method is adopted in which an electric current is applied to a heating resistor disposed in the ink chamber to rapidly generate heat, thereby vaporizing the ink in the ink chamber, and discharging the ink from the nozzles by the pressure of bubbles generated at that time. You may.
[0051]
During printing, the printing paper P is intermittently conveyed in the sub-scanning direction by a predetermined conveyance amount, and during this intermittent conveyance, the carriage 402 moves in the main scanning direction and ink droplets are ejected from each nozzle. You.
[0052]
=== Printing Method of the Present Embodiment ===
Next, a printing method according to the present embodiment will be described with reference to FIGS.
FIG. 9 is a flowchart for explaining the printing method of the present embodiment.
FIG. 10 is a schematic diagram for explaining conversion of binary halftone image data having a resolution of 720 × 720 dpi into multivalued halftone image data of 360 × 360 dpi. In FIG. 10, for convenience of explanation, 720 dpi is represented by 24 cells, and 360 dpi is represented by 12 cells. That is, one cell is an area for forming one pixel. FIG. 10 is a schematic diagram relating to, for example, halftone image data of the C color specification for convenience of explanation. The same applies to other halftone image data of the M, Y, and K colors.
[0053]
FIG. 11 is a diagram showing a relationship between the control unit 600 and the head driver 204. FIG. 11A illustrates the formation of a large dot in one pixel region. That is, when the computer 4 supplies the data “11” in units of one pixel constituting the print data PD to the control unit 600, the CPU 602 forms large dots in the process of moving the carriage 402 by one pixel in the main scanning direction. Are supplied to the head driver 204. The head driver 204 supplies the head 202 with a drive signal for discharging a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi in synchronization with a plurality of pulses. As a result, the head 202 continuously ejects a minimum unit of ink droplets corresponding to a resolution of 360 × 360 dpi onto one pixel area of the printing medium in synchronization with the plurality of pulses. For example, when the CPU 602 generates three pulses in response to data “11” in units of one pixel, the head 202 continuously discharges one pixel region of the printing medium so that ink droplets in the minimum unit partially overlap. . As a result, a large dot is formed in one pixel region by partially overlapping the three minimum ink droplets.
[0054]
FIG. 11B illustrates the formation of a small dot on the left side of one pixel area. That is, when the computer 4 supplies the data “10” in units of one pixel that constitutes the print data PD to the control unit 600, the CPU 602 determines that the carriage 402 moves by one pixel in the main scanning direction to the left of the one pixel area. A single pulse for forming a small dot is supplied to the head driver 204. The head driver 204 supplies the head 202 with a drive signal for discharging a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi in synchronization with a single pulse. As a result, the head 202 ejects a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi to the left of one pixel area of the printing medium in synchronization with a single pulse. For example, when the CPU 602 generates only one pulse on the left side of the above three pulses in response to the data “10” in units of one pixel, the head 202 causes the minimum unit of the ink droplet to be printed in one pixel of the printing medium. Discharge to the left of the area. As a result, small dots are formed on the left side of one pixel area.
[0055]
FIG. 11C illustrates formation of a small dot on the right side of one pixel area. That is, when the computer 4 supplies the data “01” in units of one pixel that constitutes the print data PD to the control unit 600, the CPU 602 determines that the carriage 402 moves by one pixel in the main scanning direction to the right of the one pixel area. A single pulse for forming a small dot is supplied to the head driver 204. The head driver 204 supplies the head 202 with a drive signal for discharging a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi in synchronization with a single pulse. Thus, the head 202 ejects a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi to the right of one pixel area of the printing medium in synchronization with a single pulse. For example, when the CPU 602 generates only one pulse on the right side of the three pulses in response to the data “01” in units of one pixel, the head 202 causes the minimum unit of the ink droplet to be printed in one pixel of the printing medium. Discharge to the right of the area. As a result, a small dot is formed on the right side of one pixel area.
[0056]
FIG. 11D explains that dots are not formed in one pixel region. That is, when the computer 4 supplies the data “00” in units of one pixel constituting the print data PD to the control unit 600, the CPU 602 causes the carriage 402 to move in the main scanning direction by one pixel, and the dot is placed in one pixel area. Are not supplied to the head driver 204.
[0057]
First, when the power is turned on, the control unit 600 initializes the CR motor driver 406, the PF motor driver 110, the head driver 204, and the pump motor driver 308 according to the result of decoding the initialization program data read from the memory 610. Supply a control signal for As a result, the carriage 402 stops at a predetermined initial position by transmitting the driving force of the CR motor 404. That is, the head 202 stops at the same initial position as the carriage 402.
[0058]
In this initial state, when the application program 12 outputs a print command for executing the print instruction from the user based on the print instruction from the user, the video driver 8 displays the image data specified by the user on the CRT 6. On the other hand, the printer driver 8 starts executing the following sequence for converting the image data designated by the user into the print data PD and supplying the print data PD to the color inkjet printer 2. It is assumed that the image data is converted into print data PD having a resolution of, for example, 360 × 360 dpi (S2).
[0059]
The resolution conversion module 14 converts the image data specified by the user output from the application program 12 into color image data of an RGB color system having a resolution higher than that used when printing on a printing medium, for example, a resolution of 720 × 720 dpi. Conversion is performed (S4).
[0060]
The color conversion module 16 refers to the color conversion look-up table LUT to convert the RGB color system color image data output from the resolution conversion module 14 into a plurality of pixels that can be used by the color inkjet printer 2 on a pixel-by-pixel basis. Is converted into multi-tone color image data of the CMYK color system having the ink colors (S6).
[0061]
The halftone module 18 refers to a dither table 20 for performing a dither method, a gamma table 24 for performing γ correction, and an error memory 22 for storing a diffused error when performing an error diffusion method. By performing the halftone process on the multi-tone color image data of the CMYK color system output from the color conversion module 16 by using the CMYK color system, the binary values of each of the CMYK color systems having a resolution of 720 × 720 dpi are obtained. Of the halftone image data (pixel data). FIG. 10A shows binary halftone image data (for example, alphabetic character “A”) of the C color system output from the halftone module 18 at the position where dot display is performed for each pixel. Only the logical value “1” is added and the logical value “0” is omitted (S8).
[0062]
The resolution multi-level conversion module 26 divides the binary halftone image data output from the halftone module 18 into pixel rows L1 to L12 in units of two horizontal pixel rows. Next, the multilevel resolution conversion module 26 performs a logical OR operation on each of the pixel columns L1 to L12 in units of two vertically adjacent pixels to convert the two-bit data in the vertical direction into one-bit data. I do. Thus, the two pixel columns L1 to L12 are converted into one pixel column L1 ′ to L12 ′. That is, the binary halftone image data having a resolution of 720 × 720 dpi in FIG. 10A is once converted into binary halftone image data having a resolution of 720 × 360 dpi in FIG. 10B ( S10).
[0063]
The resolution multi-level conversion module 26 divides each of the pixel rows L1 ′ to L12 ′ into two horizontally adjacent pixels C1 to C12. Next, the resolution multi-level conversion module 26 detects the number of pixels and the pixel position of the logical value “1” requiring the dot formation for the two pixels C1 to C12 of each pixel row L1 ′ to L12 ′. I do. As a result, the resolution conversion module 26 converts the two pixels C1 to C12 into one pixel C1 'to C12', and gives one pixel C1 'to C12' two-bit data according to the number of pixels and the pixel position. (S12).
[0064]
When the resolution multi-level conversion module 26 determines that the number of pixels of the logical value “1” that requires dot formation is two in the detection result of step S12 (S14: YES), the corresponding one pixel A logical value “11” is assigned to C1 ′ to C12 ′ (S16).
[0065]
On the other hand, when the resolution multi-level conversion module 26 determines that the number of pixels of the logical value “1” requiring the dot formation is not two pixels in the detection result of step S12 (S14: NO), Whether the number of pixels of the logical value "1" requiring formation is one pixel (S18), and whether the pixel position of the logical value "1" requiring formation of dots is on the left side (or right side) It is necessary to determine whether or not (S20) and the like, and execute a process according to the result of the determination.
[0066]
If the resolution multi-level conversion module 26 determines that the number of pixels of the logical value “1” that requires dot formation is one pixel and the pixel position is on the left side in the detection result of step S12 (S18: YES, S20) : YES), and assigns a logical value “10” to the corresponding one of the pixels C1 ′ to C12 ′ (S22). If it is determined in the detection result in step S12 that the number of pixels having the logical value “1” that requires dot formation is one pixel and the pixel position is on the right side (S18: YES, S20: NO), this is true. A logical value “01” is assigned to one pixel C1 ′ to C12 ′ (S24). When it is determined that the number of pixels having the logical value "1" requiring dot formation is 0 (S18: NO), the logical value "00" is assigned to the corresponding one pixel C1 'to C12'. (S26). Accordingly, the binary halftone image data having a resolution of 720 × 720 dpi in FIG. 10A is converted into a multi-valued image having a resolution of 360 × 360 dpi in FIG. 10C through the process of FIG. 10B. Is converted to halftone image data.
[0067]
The rasterizer 28 arranges the CMYK color system multi-valued halftone image data output from the resolution multi-value conversion module 26 in the order of data to be supplied to the color ink jet printer 2, and as the print data PD, the color ink jet printer 2 (S28).
[0068]
In the color inkjet printer 2, when printing is performed, the CPU 602 generates a pulse corresponding to the 2-bit data of each pixel in FIG. As a result, as shown in FIG. 10D, each pixel of the print image is a combination of a large dot, a small dot on the left side, a small dot on the right side, and no dot as appropriate, and the quality of the print image at low resolution. Improves. More specifically, although the printing resolution is a low resolution of 360 × 360 dpi, large dots and small dots are appropriately arranged at the portion indicated by the arrow X in FIG. On the other hand, in the portion indicated by arrow Y in FIG. 10 (d), large dots and small dots can be appropriately arranged to prevent thinning of the lower part of the alphabet letter "A", and the printed image at low resolution can be printed. Quality will be improved. Further, the image data is converted into print data by the printer driver 10, and the print data is supplied to the color inkjet printer 2, so that the color inkjet printer 2 can perform printing at a low resolution without lowering the throughput for printing. Can improve the quality of the print image. In general, the number of fine paper feeds during printing may be smaller during low-resolution printing than during high-resolution printing. Therefore, according to the present embodiment, not only during print data transfer but also during a print operation, the effect of improving the quality of a low-resolution print image without lowering the throughput is achieved. This effect is exerted not only in a print control device in which a printer and a computer are separately configured, but also in a print control device in which the printer includes the printer driver 10 and does not require transfer of print data between devices.
[0069]
FIG. 9 shows one processing procedure for realizing the conversion of FIG. 10, and can be replaced with another processing procedure that can realize the conversion of FIG. In particular, the processing in step S10 in FIG. 9 may be performed by converting a plurality of pixel rows into a smaller number of pixel rows than the plurality of pixel rows, and converting the two rows into one row described in the printing method of the present embodiment. It is not limited. That is, the number of pixel rows before and after conversion can be appropriately selected within a range where the effects of the present invention can be obtained.
[0070]
Further, the resolution of the binary halftone image data output from the resolution conversion module 14 may be higher than the resolution of the multilevel halftone image data output from the resolution multilevel conversion module 26. The resolution is not limited to that described in the printing method of the embodiment. That is, as the former resolution is higher than the latter resolution, the quality of a print image at a lower resolution is improved.
[0071]
Further, the number of pulses per pixel output from the CPU 602 is not limited to the three pulses described in the printing method of the present embodiment. For example, when the number of pulses per pixel is set to be greater than three, the number of pulses for forming a small dot may be plural.
[0072]
=== Printing Example of the Present Embodiment ===
Next, an actual print image on a printing medium will be described with reference to FIG. FIG. 12A shows print characters when the conversion of the present embodiment is not executed, and FIG. 12B shows print characters when the conversion of the present embodiment is executed. The resolution of the print character is 360 × 360 dpi. In FIG. 12A, since the outline of the character is not smooth, it is difficult to determine the shape of the character. However, in FIG. 12B, since the conversion according to the present embodiment is performed, the outline of the character is smoothed, and in an environment in which printing is performed at a low resolution of 360 × 360 dpi, a beautiful printed character is provided. Becomes possible. It is to be noted that the same effect as characters can be obtained in illustrations and the like other than characters.
[0073]
=== Other Printing Method of the Present Embodiment ===
Next, another printing method according to the present embodiment will be described with reference to FIGS. 13, 14, 15, and 16. FIG.
FIG. 13 is a flowchart for explaining another printing method according to the present embodiment.
[0074]
FIG. 14 is a schematic diagram for explaining conversion of binary halftone image data having a resolution of 720 × 720 dpi into multivalued halftone image data of 360 × 360 dpi. In FIG. 14, for convenience of explanation, 720 dpi is represented by 24 squares, and 360 dpi is represented by 12 squares. That is, one cell is an area for forming one pixel. FIG. 14 is a schematic diagram relating to, for example, halftone image data of the C color specification for convenience of explanation. The same applies to other halftone image data of the M, Y, and K colors.
[0075]
FIG. 15 is a diagram showing the relationship between the control unit 600 and the head driver 204. FIG. 15A illustrates the formation of a large dot in one pixel area. That is, when the computer 4 supplies the data “011” in units of one pixel constituting the print data PD to the control unit 600, the CPU 602 forms a large dot while the carriage 402 moves by one pixel in the main scanning direction. Are supplied to the head driver 204. The head driver 204 supplies the head 202 with a drive signal for discharging a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi in synchronization with a plurality of pulses. As a result, the head 202 continuously ejects a minimum unit of ink droplets corresponding to a resolution of 360 × 360 dpi onto one pixel area of the printing medium in synchronization with the plurality of pulses. For example, when the CPU 602 generates three pulses in response to the data “011” in units of one pixel, the head 202 continuously discharges one pixel region of the printing medium so that the ink droplets in the minimum unit partially overlap. . As a result, a large dot is formed in one pixel region by partially overlapping the three minimum ink droplets.
[0076]
FIG. 15B illustrates formation of a small dot on the left side of one pixel area. That is, when the computer 4 supplies the data “010” in units of one pixel that constitutes the print data PD to the control unit 600, the CPU 602 determines that the carriage 402 moves by one pixel in the main scanning direction to the left of the one pixel area. A single pulse for forming a small dot is supplied to the head driver 204. The head driver 204 supplies the head 202 with a drive signal for discharging a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi in synchronization with a single pulse. As a result, the head 202 ejects a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi to the left of one pixel area of the printing medium in synchronization with a single pulse. For example, when the CPU 602 generates only one pulse on the left side of the three pulses in response to the data “010” in units of one pixel, the head 202 causes the minimum unit of an ink droplet to be printed in one pixel of the printing medium. Discharge to the left of the area. As a result, small dots are formed on the left side of one pixel area.
[0077]
FIG. 15C illustrates formation of a small dot on the right side of one pixel region. That is, when the computer 4 supplies the data “001” in units of one pixel that constitutes the print data PD to the control unit 600, the CPU 602 determines that the carriage 402 moves by one pixel in the main scanning direction, A single pulse for forming a small dot is supplied to the head driver 204. The head driver 204 supplies the head 202 with a drive signal for discharging a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi in synchronization with a single pulse. Thus, the head 202 ejects a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi to the right of one pixel area of the printing medium in synchronization with a single pulse. For example, when the CPU 602 generates only one pulse on the right side among the above three pulses in response to the data “001” in units of one pixel, the head 202 causes the minimum unit of an ink droplet to be printed in one pixel of the printing medium. Discharge to the right of the area. As a result, a small dot is formed on the right side of one pixel area.
[0078]
FIG. 15D illustrates the formation of small dots on the left and right sides of one pixel area. That is, when the computer 4 supplies the data “100” in units of one pixel constituting the print data PD to the control unit 600, the CPU 602 determines that the carriage 402 moves by one pixel in the main scanning direction and the left side of the one pixel area. A plurality of pulses for forming small dots on the right side are supplied to the head driver 204. The head driver 204 supplies the head 202 with a drive signal for discharging a minimum unit of ink droplet corresponding to a resolution of 360 × 360 dpi in synchronization with a plurality of pulses. Thus, the head 202 ejects an ink droplet of the minimum unit corresponding to the resolution of 360 × 360 dpi to the left of one pixel area of the printing medium in synchronization with the plurality of pulses. For example, when the CPU 602 generates only two pulses on the left and right sides of the three pulses in response to the data “100” of one pixel unit, the head 202 causes the minimum unit of ink droplet to be printed on the printing medium. Discharge is performed on the left and right sides of one pixel area. As a result, small dots are formed on the left and right sides of one pixel area.
[0079]
FIG. 15E explains that dots are not formed in one pixel region. That is, when the computer 4 supplies the data “000” in units of one pixel which constitutes the print data PD to the control unit 600, the CPU 602 causes the carriage 402 to move in the main scanning direction by one pixel and to print dots in one pixel area. Are not supplied to the head driver 204.
[0080]
FIG. 16 is a diagram showing the relationship between the number of pixels and the pixel positions that require dot formation in a block of four pixels. FIG. 16A explains that the number of pixels that require dot formation is three or more. In this case, the computer 4 supplies the control unit 600 with one-pixel data “011” constituting the print data PD regardless of the pixel position in the block. FIG. 16B illustrates that the number of pixels requiring dot formation is two or less and the pixel position is on the left side. In this case, the computer 4 supplies the control unit 600 with the data “010” of one pixel constituting the print data PD. FIG. 16C illustrates that the number of pixels requiring dot formation is two or less and the pixel position is on the right side. In this case, the computer 4 supplies the control unit 600 with one-pixel data “001” that constitutes the print data PD. FIG. 16D illustrates that the number of pixels requiring dot formation is two pixels and the pixel position is on the upper side or the lower side. In this case, the computer 4 supplies the control unit 600 with data “100” in units of one pixel, which constitutes the print data PD.
[0081]
First, when the power is turned on, the control unit 600 initializes the CR motor driver 406, the PF motor driver 110, the head driver 204, and the pump motor driver 308 according to the result of decoding the initialization program data read from the memory 610. Supply a control signal for As a result, the carriage 402 stops at a predetermined initial position by transmitting the driving force of the CR motor 404. That is, the head 202 stops at the same initial position as the carriage 402.
[0082]
In this initial state, when the application program 12 outputs a print command for executing the print instruction from the user based on the print instruction from the user, the video driver 8 displays the image data specified by the user on the CRT 6. On the other hand, the printer driver 8 starts executing the following sequence for converting the image data designated by the user into the print data PD and supplying the print data PD to the color inkjet printer 2. It is assumed that the image data is converted into print data PD having a resolution of, for example, 360 × 360 dpi (S102).
[0083]
The resolution conversion module 14 converts the image data specified by the user output from the application program 12 into color image data of an RGB color system having a resolution higher than that used when printing on a printing medium, for example, a resolution of 720 × 720 dpi. Conversion is performed (S104).
[0084]
The color conversion module 16 refers to the color conversion look-up table LUT to convert the RGB color system color image data output from the resolution conversion module 14 into a plurality of pixels that can be used by the color inkjet printer 2 on a pixel-by-pixel basis. Is converted into CMYK color system multi-gradation color image data having the ink colors (S106).
[0085]
The halftone module 18 refers to a dither table 20 for performing a dither method, a gamma table 24 for performing γ correction, and an error memory 22 for storing a diffused error when performing an error diffusion method. By performing the halftone process on the multi-tone color image data of the CMYK color system output from the color conversion module 16 by using the CMYK color system, the binary values of each of the CMYK color systems having a resolution of 720 × 720 dpi are obtained. Of the halftone image data (pixel data). FIG. 14A shows binary halftone image data (for example, alphabetic character “A”) of the C color system output from the halftone module 18, and is located at a position where dot display is performed for each pixel. Only the logical value "1" is added, and the addition of the logical value "0" is omitted (S108).
[0086]
The resolution multilevel conversion module 26 divides the binary halftone image data output from the halftone module 18 into blocks each having, for example, 4 pixels of 2 pixels vertically × 2 pixels horizontally. Next, the multilevel resolution conversion module 26 detects, for each block, the number of pixels and the pixel position of the logical value “1” that requires dot formation. As a result, the resolution conversion module 26 converts the block of four pixels into one pixel, and gives the one pixel 3-bit data according to the number of pixels and the pixel position (S110).
[0087]
When the resolution multi-level conversion module 26 determines that the number of pixels of the logical value “1” that requires dot formation is three or more in the detection result of step S110 (S112: YES), the corresponding 1 A logical value “011” is assigned to the pixel (S114).
[0088]
On the other hand, when the resolution multi-level conversion module 26 determines that the number of pixels of the logical value “1” that requires dot formation is not three or more in the detection result of step S110 (S112: NO), Whether or not the number of pixels of the logical value "1" requiring the formation of the pixel is two (S116), and if the result in the step S116 is affirmative, the pixel position of the logical value "1" requiring the formation of the dot is on the left side. Is determined (S118), and whether the pixel position of the logical value "1" requiring dot formation is only on the right side (S120), etc., and a process corresponding to the determination result is executed. Must.
[0089]
The resolution multi-level conversion module 26 determines that the number of pixels of the logical value “1” requiring the dot formation is two pixels and the pixel position is only on the left side in the detection result of step S110 (S116: YES, S118: YES), and assigns a logical value “010” to the converted one pixel of the corresponding block (S122). If it is determined in the detection result of step S110 that the number of pixels having the logical value "1" requiring dot formation is two and the pixel position is only on the right side (S116: YES, S118: NO, S120: YES), a logical value “001” is assigned to one converted pixel of the corresponding block (S124). In addition, in the detection result of step S110, when it is determined that the number of pixels having the logical value "1" requiring dot formation is 2 pixels and the pixel position is neither on the left side nor on the right side (S116: YES, S118: NO) , S120: YES), since the pixel position of the two pixels is on the upper side or lower side of the block, a logical value “100” is assigned to one converted pixel of the corresponding block (S126).
[0090]
In step S116, the resolution multi-level conversion module 26 determines whether or not the number of pixels of the logical value "1" requiring dot formation is one (S128), and further necessitates dot formation. It is necessary to determine whether or not the pixel position of the logical value “1” to be performed is on the left side (or right side) (S130) or the like, and to execute processing according to the result of this determination.
[0091]
The resolution multi-level conversion module 26 determines that the number of pixels of the logical value “1” requiring dot formation is one pixel and the pixel position is on the left side in the detection result of step S110 (S128: YES, S130). : YES), a logical value “010” is assigned to one converted pixel of the corresponding block (S122). If it is determined in the detection result in step S110 that the number of pixels having the logical value "1" requiring dot formation is one pixel and the pixel position is on the right side (S128: YES, S130: NO), this is true. A logical value “001” is assigned to one pixel after the block conversion (S124). If it is determined in the detection result of step S110 that the number of pixels having the logical value "1" requiring dot formation is not one pixel (S128: NO), it means that no dot is to be formed. A logical value “000” is assigned to one pixel after the conversion (S132). As a result, the binary halftone image data having a resolution of 720 × 720 dpi in FIG. 14A is converted into multivalued halftone image data having a resolution of 360 × 360 dpi in FIG. 14B.
[0092]
In the rasterizer 28, the multi-valued halftone image data output from the resolution multi-value conversion module 26 is arranged in the data order for supply to the color inkjet printer 2, and is supplied to the color inkjet printer 2 as print data PD (S134). ).
[0093]
In the color inkjet printer 2, when performing printing, the CPU 602 generates a pulse corresponding to the 3-bit data of each pixel in FIG. As a result, as shown in FIG. 14C, each pixel of the print image is a combination of a large dot, a small dot on the left side, a small dot on the right side, a small dot on both the left and right sides, and a no dot. The quality of the printed image at the point is improved.
[0094]
FIG. 13 shows one processing procedure for realizing the conversion shown in FIG. 14, and can be replaced with another processing procedure that can realize the conversion shown in FIG.
[0095]
Further, the resolution of the binary halftone image data output from the resolution conversion module 14 may be higher than the resolution of the multilevel halftone image data output from the resolution multilevel conversion module 26. The resolution is not limited to that described in the printing method of the embodiment. That is, as the former resolution is higher than the latter resolution, the quality of a print image at a lower resolution is improved.
[0096]
Further, the number of pulses per pixel output from the CPU 602 is not limited to the three pulses described in the printing method of the present embodiment. For example, when the number of pulses per pixel is set to be greater than three, the number of pulses for forming a small dot may be plural.
[0097]
Further, the data of one pixel constituting the print data PD is not limited to 3-bit data, but may be 2-bit data, for example. In this case, in each block, when the number of pixels requiring dot formation is 3 or more, or when the number of pixels requiring dot formation is 2 pixels and the pixel position is on the upper or lower side The computer 4 supplies the control unit 600 with the data “11” in units of one pixel constituting the print data PD, regardless of the pixel position in the block. When the number of pixels requiring dot formation is 2 pixels or less and the pixel position is on the left side in each block, the computer 4 controls the data “10” in units of one pixel constituting the print data PD by the control unit. 600. When the number of pixels requiring dot formation is 2 pixels or less and the pixel position is on the right side in each block, the computer 4 controls the data “01” in units of one pixel constituting the print data PD by the control unit. 600. In addition, when there is no pixel requiring dot formation in each block, the computer 4 supplies the control unit 600 with one-pixel data “00” constituting the print data PD. When this embodiment is executed, multi-valued halftone image data similar to that shown in FIG. 10D can be obtained, and a print image similar to that shown in FIG. 12B can be obtained.
[0098]
When a low-resolution image (characters, illustrations, etc.) is printed on a printing medium, the low-resolution image is printed using dots (large dots) having a certain size. The portion may not be smooth and the quality of the printed image may be degraded. Therefore, by replacing only the outline portion of the print image with large dots and small dots, it is possible to prevent the quality of the print image from deteriorating. However, since the image data that is the basis for printing remains at a low resolution, for example, when the outline of a low-resolution character or a ruled line is replaced from a large dot to a small dot, the character or the ruled line becomes thin and poor. May be visible.
[0099]
Therefore, the print data PD is obtained based on image data having a higher resolution than the resolution of the data, so that it is possible to improve the quality of a low-resolution print image.
[0100]
Further, the image data may be data supplied to the printer driver 10.
Accordingly, since the image data has a higher resolution than the resolution of the print data PD before being converted into the print data PD, the quality of the print image at a low resolution can be improved using this image data. .
[0101]
Further, the image data may be color-converted by the color conversion module 16 into CMYK color system data and then converted into print data PD.
This makes it possible to improve the quality of a low-resolution print image using CMYK color system data obtained by color-converting image data.
[0102]
The image data may be converted into print data PD after being converted into binary halftone image data (pixel data) of the CMYK color system by the halftone module 18.
This makes it possible to improve the quality of a low-resolution print image using binary halftone image data.
[0103]
Also, a plurality of pixels in the binary halftone image data and a single pixel in the print data PD are made to correspond to each other, and the binary halftone image data is set to the number of pixels that need to form dots in the plurality of pixels. Accordingly, the data may be converted into print data PD for forming any one of a plurality of sizes of dots in a single pixel.
Thereby, according to the number of pixels for forming a dot in a plurality of pixels, the print data PD for forming any one of a plurality of sizes of dots in a single pixel is obtained, thereby achieving low-resolution printing. The quality of a printed image can be improved.
[0104]
A plurality of pixels in the binary halftone image data correspond to a single pixel in the print data PD, and the binary halftone image data has a predetermined number of pixels for which dots need to be formed within the plurality of pixels. When the number is greater than or equal to the number, a large dot is formed in a single pixel, and when the number of pixels requiring dot formation in a plurality of pixels is less than a predetermined number, the data is converted to print data PD for forming a small dot. It may be.
Accordingly, by obtaining print data PD for forming dots of different sizes in a single pixel according to the number of pixels for forming dots in a plurality of pixels, the quality of a print image at low resolution is obtained. Can be improved.
[0105]
A plurality of pixels in the binary halftone image data correspond to a single pixel in the print data PD, and the binary halftone image data has a predetermined number of pixels for which dots need to be formed within the plurality of pixels. When the number is less than the number, the print data PD may be converted into print data PD for forming a small dot at one of the left and right positions of a single pixel in accordance with a pixel position where a dot needs to be formed within a plurality of pixels. .
Accordingly, when the number of pixels for forming dots in a plurality of pixels is less than a predetermined number and at a predetermined position, print data PD for forming a small dot at one of the left and right positions of a single pixel is obtained. Thus, the quality of a print image at a low resolution can be improved.
[0106]
Also, a plurality of pixels in the binary halftone image data and a single pixel in the print data PD are respectively associated with each other, and the binary halftone image data has a smaller number than a plurality of pixels in units of a plurality of pixel columns in a predetermined direction. Is converted into a pixel column, and then a plurality of large pixels are placed at a predetermined position of a single pixel in accordance with the number of pixels and the pixel position for which dots need to be formed in a plurality of adjacent pixels among the plurality of pixel columns. May be converted into print data for forming any of the dots.
Thereby, first, a plurality of pixel rows in a predetermined direction in the pixel data are respectively converted into a smaller number of pixel rows than the plurality of pixel rows. By obtaining print data PD for forming any of a plurality of sizes of dots at a predetermined position of a single pixel in accordance with the number of pixels and the pixel positions that need to be formed, a print image of low resolution can be obtained. Quality can be improved.
[0107]
In addition, a plurality of pixels in the binary halftone image data and a single pixel in the print data PD are respectively associated with each other, and the binary halftone image data requires dots to be formed in a block having a plurality of pixels as a unit. The print data PD may be converted into print data PD for forming one of a plurality of sizes of dots at a predetermined position of a single pixel in accordance with the number of pixels and the pixel position to be performed.
Accordingly, printing for forming any one of a plurality of sizes of dots at a predetermined position of a single pixel in accordance with the number of pixels and the pixel position for which dots need to be formed in a block having a plurality of pixels as a unit. By efficiently obtaining the data PD, it is possible to improve the quality of a print image at a low resolution.
[0108]
Also, a plurality of pixels in the binary halftone pixel data correspond to a single pixel in the print data PD, and the halftone image data of the plurality of pixels is converted into the print data PD by the computer 4, and this converted The print data PD may be supplied to the color inkjet printer 2.
As a result, the halftone image data of a plurality of pixels is converted into print data PD by the computer 4, and the converted print data PD is supplied to the color inkjet printer 2. The transfer time of the data PD is shortened, and the quality of a print image at a low resolution can be improved without lowering the throughput for printing.
[0109]
Further, a transporting means (PF motor 108, PF motor driver 110) for transporting the printing medium in the sub-scanning direction, and a printing medium by moving in the main scanning direction intersecting the sub-scanning direction and ejecting ink. And a head 202 for performing printing.
This makes it possible to improve the quality of a printed image at a low resolution by using an apparatus having the transporting units 108 and 110 for transporting the printing medium and the head 202 for performing printing on the printing medium. it can.
[0110]
=== Other Embodiments ===
As described above, the print control apparatus, the print method, the program, and the computer system according to the present invention have been described based on one embodiment. However, the above-described embodiment of the present invention is for facilitating understanding of the present invention. It is not intended to limit the invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.
[0111]
Small dots may be formed at the upper position and the lower position in addition to the left position and the right position in each pixel constituting the print image on the printing medium. This makes it possible to bring a low-resolution print image closer to the definition of the original image data.
[0112]
In the above embodiment, the paper S is applied as the printing medium, but the invention is not limited to this. That is, in the present invention, a film, a cloth, a thin metal plate, or the like can be applied as the printing medium.
[0113]
The color inkjet printer 2 may have some of the functions or mechanisms of the computer main unit, the display device, the input device, the flexible disk drive device, and the CD-ROM drive device. For example, the color inkjet printer 2 includes an image processing unit for performing image processing, a display unit for performing various displays, and a recording medium attaching / detaching unit for attaching / detaching a recording medium for recording image data captured by a digital camera or the like. It may be configured.
[0114]
Although the color inkjet printer 2 is applied in the above embodiment, the invention is not limited to this. That is, the present invention can be applied to a monochrome inkjet printer, a printer other than the inkjet system, and the like. Further, the present invention can be applied to a printing apparatus such as a facsimile machine and a copying machine.
[0115]
【The invention's effect】
According to the present invention, it is possible to improve the quality of a low-resolution print image.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of a computer system of the present invention.
FIG. 2 is a diagram for explaining the overall configuration of the color inkjet printer of the embodiment.
FIG. 3 is a schematic diagram for explaining the periphery of a carriage of the color inkjet printer according to the embodiment.
FIG. 4 is a diagram for explaining the vicinity of a transport unit of the inkjet printer according to the embodiment.
FIG. 5 is a perspective view illustrating the vicinity of a transport unit of the inkjet printer according to the embodiment.
FIG. 6 is an explanatory diagram of a linear encoder 502.
FIG. 7 is a timing chart showing waveforms of two types of output signals of the linear encoder 502.
FIG. 8 is a diagram for explaining an arrangement of nozzles on a lower surface of a head 202.
FIG. 9 is a flowchart illustrating a printing method according to the embodiment.
FIG. 10 is a schematic diagram for explaining conversion of binary halftone image data having a resolution of 720 × 720 dpi into multivalued halftone image data of 360 × 360 dpi.
FIG. 11 is a diagram showing a relationship between a control unit 600 and a head driver 204.
FIG. 12 is a diagram illustrating an actual print image on a printing medium.
FIG. 13 is a flowchart illustrating another printing method according to the present embodiment.
FIG. 14 is a schematic diagram for explaining conversion of binary halftone image data having a resolution of 720 × 720 dpi into multivalued halftone image data of 360 × 360 dpi.
FIG. 15 is a diagram showing a relationship between a control unit 600 and a head driver 204.
FIG. 16 is a diagram showing the relationship between the number of pixels and the pixel positions for which dots need to be formed in a block of four pixels.
[Explanation of symbols]
2 Color inkjet printer
4 Computer
6 CRT
8 Video Driver
10 Printer driver
12 Application programs
14 Resolution conversion module
16 color conversion module
18 Halftone module
20 dither table
22 Error memory
24 Gamma table
26 Resolution Multi-value Conversion Module
28 Rasterizer
30 User interface display module
32 UI printer interface module
100 paper transport unit
102A paper insertion slot
102B Roll paper insertion slot
104 Paper feed roller
106 Platen
108 PF motor
110 PF motor driver
112A paper feed roller
112B discharge roller
114A, 114B Free roller
200 ink ejection unit
202 head
204 Head Driver
300 cleaning unit
302 pump device
304 capping device
306 Pump motor
308 Pump motor driver
400 carriage unit
402 carriage
404 CR motor
406 CR motor driver
408 pulley
410 Timing Belt
412 Guide rail
500 measuring instruments
502 linear encoder
504 Rotary encoder
506 Paper detection sensor
508 Paper width sensor
532 linear scale
534A Light Emitting Diode
534B Collimator lens
534C detection processing unit
534D photodiode
534E signal processing circuit
534Fa, 534Fb Comparator
600 control unit
602 CPU
604 Timer IC
606 Interface section
608 ASIC
610 memory
612 DC Controller

Claims (15)

A printing apparatus capable of converting image data into print data for forming dots of a plurality of sizes, and forming dots on a printing medium based on the print data,
The print control apparatus according to claim 1, wherein the print data is obtained by converting the image data having a higher resolution than that of the print data. The print control device according to claim 1,
The print control apparatus according to claim 1, wherein the image data is data supplied to a driver for converting the image data into the print data. The print control device according to claim 1 or 2,
A print control apparatus, wherein the image data is converted into the print data after being color-converted into CMYK color system data. The print control device according to claim 1, wherein
A print control apparatus, wherein the image data is converted into the print data after being converted into pixel data in a form in which each pixel corresponds to the necessity of dot formation. The print control device according to claim 4,
A plurality of pixels in the pixel data and a single pixel in the print data respectively correspond,
The pixel data is converted to the print data for forming any one of a plurality of sizes of dots in the single pixel according to the number of pixels that need to form dots in the plurality of pixels. A print control device characterized by the above-mentioned. The print control device according to claim 5,
A plurality of pixels in the pixel data and a single pixel in the print data respectively correspond,
The pixel data forms a first dot of a predetermined size in the single pixel when the number of pixels requiring dot formation in the plurality of pixels is equal to or greater than a predetermined number. A print control apparatus, wherein when the number of pixels that need to be formed is less than a predetermined number, the print data is converted into the print data for forming a second dot smaller than the first dot in the single pixel. The print control device according to claim 4, wherein
A plurality of pixels in the pixel data and a single pixel in the print data respectively correspond,
The pixel data, when the number of pixels that need to form a dot in the plurality of pixels is less than a predetermined number, according to the pixel position that needs to form a dot in the plurality of pixels, A print control device, wherein the print data is converted into the print data for forming the second dot at a position. The print control device according to any one of claims 4 to 7,
A plurality of pixels in the pixel data and a single pixel in the print data respectively correspond,
The pixel data is converted into a plurality of pixel rows smaller than the plurality of pixel rows in units of a plurality of pixel rows in a predetermined direction, and thereafter, it is necessary to form dots in a plurality of adjacent pixels among the plurality of pixel rows smaller than the plurality. The print control device converts the print data into the print data for forming one of a plurality of sizes of dots at a predetermined position of the single pixel according to the number of pixels and the pixel position. The print control device according to any one of claims 4 to 7,
A plurality of pixels in the pixel data and a single pixel in the print data respectively correspond,
The pixel data forms any one of a plurality of sizes of dots at a predetermined position of the single pixel according to the number of pixels and the pixel position at which dots need to be formed in the block in units of the plurality of pixels. A print control device for converting the print data into print data. The print control device according to any one of claims 1 to 9,
A plurality of pixels in the pixel data and a single pixel in the print data respectively correspond,
A print control apparatus, wherein the image data of the plurality of pixels is converted into the print data by a computer, and the converted print data is supplied to a printing apparatus. The print control device according to any one of claims 1 to 10,
Conveying means for conveying the printing medium in the sub-scanning direction, and a print head for performing printing on the printing medium by ejecting ink by moving in a main scanning direction intersecting the sub-scanning direction; , A print control device. A print control device capable of converting image data into print data for forming dots of a plurality of sizes, and forming dots on a printing medium based on the print data,
The print data is obtained by converting the image data having a higher resolution than that of the print data,
The image data is supplied to driver means for converting the image data into the print data,
The image data is color-converted into CMYK color system data and subjected to halftone processing, so that each pixel and pixel formation necessity are converted into pixel data of a corresponding form, and then converted to the print data. And
A plurality of pixels in the pixel data are associated with a single pixel in the print data, and the pixel data is the single pixel when the number of pixels requiring dot formation in the plurality of pixels is a predetermined number or more. Form a first dot of a predetermined size, and when the number of pixels that require dot formation in the plurality of pixels is less than a predetermined number, form a second dot smaller than the first dot in the single pixel Is converted to the print data for
A plurality of pixels in the pixel data correspond to a single pixel in the print data, respectively, and the pixel data is included in the plurality of pixels when the number of pixels requiring dot formation in the plurality of pixels is less than a predetermined number. In accordance with the pixel position that requires the formation of a dot, is converted to the print data for forming the second dot at a predetermined position of the single pixel,
A plurality of pixels in the pixel data and a single pixel in the print data are respectively associated with each other, and the pixel data is converted into a smaller number of pixel rows in units of a plurality of pixel rows in a predetermined direction. In order to form a first dot or a second dot at a predetermined position of the single pixel, depending on the number of pixels and the pixel position for which a dot needs to be formed in a plurality of adjacent pixels in a less than a plurality of pixel rows Is converted to the print data of
A plurality of pixels in the pixel data correspond to a single pixel in the print data, and the image data of the plurality of pixels is converted into the print data by a computer, and the converted print data is supplied to a printing apparatus. And
Conveying means for conveying the printing medium in the sub-scanning direction, and a print head for performing printing on the printing medium by ejecting ink by moving in a main scanning direction intersecting the sub-scanning direction; , A print control device. A printing method for a printing apparatus capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on a printing medium based on the print data,
The printing method, wherein the print data is obtained by converting the image data having a higher resolution than the print data. Converting the image data into print data for forming dots of a plurality of sizes, a print control device capable of forming dots on a printing medium based on the print data,
A program for realizing a function of converting the image data having a higher resolution than the print data to obtain the print data. A print control device capable of converting image data into print data for forming dots of a plurality of sizes and forming dots on a printing medium based on the print data; and a computer main body connected to the print control device And a computer system comprising:
The computer system according to claim 1, wherein the print data is obtained by converting the image data having a higher resolution than the print data.

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