JP2006239964A - Printing device, printing system, printing control device, printing method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing device or the like which can effectively reduces ink consumption while smoothing the profile portion of an image printed. <P>SOLUTION: The printing device comprises (A) nozzles to print an image by forming dots by discharging an ink toward a medium, (B) a controller which decides positions where the dots should be formed while specifying the positions by horizontal and vertical directions intersecting each other at right angles, and (C) a controller which makes dots smaller than oblong dots to be formed along the horizontal outline portion in an adjacent area outside the horizontal outline portion along the horizontal direction of the outline portion when the outline portion of the image is composed of a plurality of oblong dots longer in the horizontal direction than in the vertical direction and prevents dots from getting formed in an adjacent area outside the vertical outline portion along the vertical direction of the outline portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing apparatus, a printing system, a printing control apparatus, a printing method, and a program for printing an image by ejecting ink toward a medium to form dots.

Inkjet printers are known as printing apparatuses that print images on various media such as paper, cloth, and film. This ink jet printer ejects ink of each color such as cyan (C), magenta (M), yellow (Y), and black (K) toward a medium such as paper, and the ejected ink forms dots on the medium. It is formed and printed.
However, in such a printer, the outline of the printed image may be disturbed and lack sharpness. In particular, when the disturbance of the contour portion occurs in a text image such as a character or a symbol, it appears as a serious damage such as difficulty in reading or poor appearance.

The reason for the disturbance of the contour portion is that when dots are formed at the position that becomes the contour portion of the image, the ink overflows from the original contour portion to the adjacent region outside, and the ink is formed in a bowl shape there. Is that it will stick out. Therefore, as one method for eliminating and smoothing the disturbance of the contour portion of the image, there is a method of forming a small dot in the adjacent region outside the contour portion to hide the wrinkle-like disturbance ( For example, see Japanese Patent Application No. 2003-102044).
However, not all contour portions of the image are uniformly disturbed, and depending on the shape of the dot, there are contour portions that are likely to be disturbed and contour portions that are difficult to be disturbed. Therefore, even if the small outline is formed in the adjacent region outside the contour portion which is not easily disturbed, useless small dots are formed, resulting in wasteful consumption of ink. End up.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a printing apparatus and the like that can effectively suppress ink consumption while smoothing the contour of an image to be printed. With the goal.

The main invention for achieving the object is as follows:
(A) a nozzle for ejecting ink toward a medium to form dots and printing an image;
(B) A controller that determines the positions where the dots are to be formed while defining the positions in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is configured by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal region in the adjacent region outside the horizontal contour portion along the horizontal direction is included in the horizontal portion. A small dot smaller than the horizontally long dot is formed along the direction contour portion, and a dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. With the controller to avoid,
A printing apparatus comprising (C).

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

=== Summary of disclosure ===
At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

(A) a nozzle for ejecting ink toward a medium to form dots and printing an image;
(B) A controller that determines the positions where the dots are to be formed while defining the positions in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is configured by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal region in the adjacent region outside the horizontal contour portion along the horizontal direction is included in the horizontal portion. A small dot smaller than the horizontally long dot is formed along the direction contour portion, and a dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. With the controller to avoid,
A printing apparatus comprising (C).

  In general, in a horizontal outline portion in which a plurality of horizontal dots are formed along the horizontal direction, the overlapping portion of the horizontal dots is large, the ink in the overlapping portion overflows, and the vertical direction is shifted to the outer adjacent region. As a result, the outline of the image is disturbed and lacks smoothness.

  On the other hand, according to the printing apparatus, small dots are formed in the adjacent area of the horizontal outline portion and the ridge-like protruding portion of the adjacent area is hidden, so that the horizontal outline of the image is smoothed. Can be printed.

  On the other hand, the vertical contour portion in which a plurality of horizontally long dots are formed along the vertical direction has a small overlapping portion between the horizontally long dots, so that the ink in the overlapping portion moves to the adjacent region outside in the horizontal direction. As a result, the vertical outline of the image is not disturbed and is printed relatively smoothly. For this reason, if small dots are formed up to the adjacent area, ink is wasted, but according to the printing apparatus, dots are not formed in the adjacent area of the vertical contour portion. Therefore, it is not necessary to form unnecessary small dots, and it is possible to effectively prevent wasteful consumption of ink.

Such a printing apparatus,
Do not form dots in the adjacent area outside the vertical contour portion,
It is desirable to form the small dots in the adjacent region outside the vertical contour portion.
According to such a printing apparatus, the above-described effect of smoothing the contour portion of the image is not limited to the lateral contour portion in which the laterally long dots are formed along the lateral direction, but the laterally elongated dots are along the oblique direction. It can also be exerted on the diagonally contoured portion formed.

Such a printing apparatus,
When horizontally long dots are formed on both sides in the vertical direction across a blank portion of one dot, it is desirable not to form small dots in the blank portion.
According to such a printing apparatus, when a blank portion of one dot is formed in the contour portion, it is effectively prevented that the blank portion is filled with small dots and the image is not clear. be able to.

Such a printing apparatus,
In the case where horizontally long dots are formed on both sides in the horizontal direction across a blank portion of one dot, it is desirable not to form small dots in the blank portion.
According to such a printing apparatus, when a blank portion of one dot is formed in the contour portion, it is effectively prevented that the blank portion is filled with small dots and the image is not clear. be able to.

Such a printing apparatus,
The small dot is desirably a dot of the smallest size among the dots formed by the nozzle.
According to such a printing apparatus, since the small dot is a dot of the minimum size, when there is a large amount of bleeding from the horizontally long dot to the adjacent area, it does not promote the ridge-like protrusion of the adjacent area. Therefore, the outline of the image can be smoothed by effectively hiding the protruding portion of the bowl shape.

Such a printing apparatus,
The horizontally long dot is preferably a dot of the maximum size among the dots formed by the nozzle.
According to such a printing apparatus, since the horizontally long dot is a dot of the maximum size, the horizontal outline in the image is likely to be disturbed. That is, since the horizontally long dot is a dot of the maximum size, the overlapping portion of the horizontal direction outline portion becomes large, and it tends to protrude in a bowl shape in the adjacent area, and the disturbance of the horizontal direction outline of the image is remarkable. appear. Therefore, the effect of claim 1 is most effectively exhibited.

Such a printing apparatus,
The image is a text image;
It is desirable that all the horizontally long dots in the image have the same size.
According to such a printing apparatus, the outline of a text image can be smoothed and the visibility thereof can be improved.

Such a printing apparatus,
It is desirable that the size of the overlapping portion between the horizontally long dots adjacent in the horizontal direction is larger than the size of the overlapping portion between the horizontally long dots adjacent in the vertical direction.
According to such a printing apparatus, the effect of claim 1 can be effectively exhibited.

Such a printing apparatus,
The nozzle ejects ink while moving in the lateral direction,
The small dots are formed by landing a drop of ink ejected from the nozzle on the medium, and the horizontal dots are formed by a plurality of drops of ink ejected from the nozzle continuously on the medium. It is desirable to be formed.
According to such a printing apparatus, the horizontally long dots are surely formed long in the horizontal direction. That is, the horizontally long dots are formed by landing a plurality of drops of ink continuously ejected from nozzles moving in the horizontal direction on the medium. This ensures a long shape in the lateral direction. As a result, the effect of claim 1 can be effectively achieved.

(A) a nozzle for ejecting ink toward the medium to form dots and printing an image;
(B) A controller that determines the positions where the dots are to be formed while defining the positions in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is configured by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal region in the adjacent region outside the horizontal contour portion along the horizontal direction is included in the horizontal portion. A small dot smaller than the horizontally long dot is formed along the direction contour portion, and a dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. With the controller to avoid,
A printing apparatus comprising (C),
Do not form dots in the adjacent area outside the vertical contour portion,
In the adjacent area outside the vertical contour portion, the small dots are formed,
When a horizontally long dot is formed on both sides of the vertical direction across a blank portion of one dot, a small dot is not formed in the blank portion,
The printing apparatus is characterized in that, when a horizontally long dot is formed on both sides in the horizontal direction across a blank portion of one dot, a small dot is not formed in the blank portion.

The small dot is a dot of the smallest size among the dots formed by the nozzle,
The horizontally long dot is a dot of the maximum size among the dots formed by the nozzle,
The image is a text image;
The horizontally long dots in the image are all the same size,
The size of the overlapping portion between the horizontally long dots adjacent in the horizontal direction is larger than the size of the overlapping portion between the horizontally long dots adjacent in the vertical direction,
The nozzle ejects ink while moving in the lateral direction,
The small dots are formed by landing a drop of ink ejected from the nozzle on the medium, and the horizontal dots are formed by a plurality of drops of ink ejected from the nozzle continuously on the medium. A printing apparatus characterized by being formed.
According to such a printing apparatus, the object of the present invention can be achieved most effectively because almost all the operational effects described above are used.

(A) a nozzle for ejecting ink toward the medium to form dots and printing an image;
(B) A controller that determines the positions where the dots are to be formed while defining the positions in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is configured by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal region in the adjacent region outside the horizontal contour portion along the horizontal direction is included in the horizontal portion. A small dot smaller than the horizontally long dot is formed along the direction contour portion, and a dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. With the controller to avoid,
It is also possible to realize a printing system characterized by comprising (C).

Further, in a printing control apparatus for controlling a printing apparatus having nozzles for ejecting ink toward a medium to form dots and printing an image,
When the printing control device determines the positions where dots should be formed in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is constituted by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal direction in the adjacent region outside the horizontal contour portion along the horizontal direction in the contour portion. A small dot smaller than the horizontally long dot is formed along the contour portion, and no dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. It is also possible to realize a print control apparatus characterized by doing so.

Further, in a printing method for printing an image by ejecting ink toward a medium to form dots,
When determining the position where the dot is to be formed while defining the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is constituted by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal direction in the adjacent region outside the horizontal contour portion along the horizontal direction in the contour portion. A small dot smaller than the horizontally long dot is formed along the contour portion, and a dot is not formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. It is also possible to realize a printing method characterized by the above.

Further, a program executed in a printing apparatus including a nozzle for ejecting ink toward a medium to form dots and print an image,
When deciding the position where dots should be formed in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is constituted by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal direction in the adjacent region outside the horizontal contour portion along the horizontal direction in the contour portion. A step of forming small dots smaller than the horizontally long dots along the contour portion;
It is also possible to implement a program characterized by executing a step of preventing dots from being formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion.

=== Overview of Printing Apparatus ===
As an embodiment of a printing apparatus according to the present invention, an outline of a printing system 1000 including a printer main body 1 and a computer apparatus 1100 will be described as an example.

  FIG. 1 is an explanatory diagram showing an external configuration of an example of the printing system 1000. The printing system 1000 includes a printer main body 1 and a computer device (printing control device) 1100. The computer device 1100 includes a display device 1200, an input device 1300, and a recording / reproducing device 1400. Here, the printer main body 1 is constituted by an ink jet printer, and performs printing by ejecting ink toward various media such as paper, cloth, and film.

  The computer apparatus 1100 and the printer main body 1 are connected to each other so as to be able to perform data communication by wired or wireless such as a cable. The computer apparatus 1100 generates print data of an image to be printed by the printer main body 1 and outputs the print data to the printer main body 1. The display device 1200 includes a display 1201 and displays user interfaces such as an application program 1104 and a printer driver 1110. The input device 1300 includes, for example, a keyboard 1300A and a mouse 1300B, and is used for operating the application program 1104, setting the printer driver 1110, and the like along a user interface displayed on the display device 1200. The recording / reproducing apparatus 1400 includes, for example, a flexible disk drive apparatus 1400A and a CD-ROM drive apparatus 1400B.

  A printer driver 1110 (not shown) is installed in the computer device 1100. The printer driver 1110 is a program for realizing the function of displaying the user interface on the display device 1200 and the function of converting the image data output from the application program 1104 into print data. The printer driver 1110 is stored and distributed in various storage media (computer-readable recording media) such as a flexible disk FD and a CD-ROM, or distributed through various communication means such as the Internet.

=== Printer Driver 1110 ===
<About the printer driver 1110>
FIG. 2 is a schematic explanatory diagram of basic processing performed by the printer driver 1110. The components already described are given the same reference numerals, and the description thereof is omitted.

  In the computer apparatus 1100, computer programs such as a video driver 1102, an application program 1104, and a printer driver 1110 are operating under an operating system installed in the computer apparatus 1100. The video driver 1102 has a function of displaying, for example, a user interface on the display device 1200 in accordance with a display command from the application program 1104 or the printer driver 1110. The application program 1104 has a function of performing image editing, for example, and creates data related to an image (image data). The user can give an instruction to print an image edited by the application program 1104 via the user interface of the application program 1104. When the application program 1104 receives a print instruction, the application program 1104 outputs image data to the printer driver 1110.

  The printer driver 1110 receives image data from the application program 1104, converts this image data into print data, and outputs the print data to the printer main body 1. Here, the print data is data in a format that can be interpreted by the printer body 1 and includes various command data and pixel data. The command data is data for instructing the printer body 1 to execute a specific operation. The pixel data is data relating to pixels constituting an image to be printed (printed image). For example, data relating to dots (color and size of dots) formed at positions on the medium S corresponding to a certain pixel. Etc.).

  The printer driver 1110 includes a resolution conversion processing unit 1112, a color conversion processing unit 1114, a halftone processing unit 1116, and a rasterization processing unit 1118 in order to convert image data output from the application program 1104 into print data. I have. Hereinafter, various processes performed by the processing units 1112, 1114, 1116, and 1118 of the printer driver 1110 will be described.

  The resolution conversion processing unit 1112 performs resolution conversion processing for converting image data (text data, image data, etc.) output from the application program 1104 into a resolution for printing on the medium S. In the resolution conversion process, for example, when the print resolution when printing an image on paper is specified as 720 × 720 dpi, the image data received from the application program 1104 is converted into image data having a resolution of 720 × 720 dpi. Note that the image data after the resolution conversion process is multi-gradation (for example, 256 gradations) RGB data represented by an RGB color space. Hereinafter, RGB data obtained by performing resolution conversion processing on image data is referred to as RGB image data.

  The color conversion processing unit 1114 performs color conversion processing for converting RGB data into CMYK data represented by a CMYK color space. The CMYK data is data corresponding to the ink color of the printer body 1. This color conversion processing is performed by the printer driver 1110 referring to a table (color conversion lookup table LUT) in which the gradation values of RGB image data and the gradation values of CMYK image data are associated with each other. Through this color conversion process, RGB data for each pixel is converted into CMYK data corresponding to the ink color. The data after the color conversion processing is CMYK data with 256 gradations represented by the CMYK color space. Hereinafter, CMYK data obtained by performing color conversion processing on RGB image data is referred to as CMYK image data.

  The halftone processing unit 1116 performs a halftone process for converting high gradation number data into gradation number data that can be formed by the printer body 1. Halftone processing is, for example, processing for converting data representing 256 gradations into 2-bit data representing 4 gradations. In this halftone process, pixel data is created using a dither method, γ correction, error diffusion method, etc. so that the printer body 1 can form dots in a dispersed manner. When halftone processing is performed, the halftone processing unit 1116 refers to the dither table when performing the dither method, refers to the gamma table when performing γ correction, and is diffused when performing the error diffusion method. Reference is made to an error memory for storing errors. The data subjected to the halftone process has a resolution (for example, 720 × 720 dpi) equivalent to the RGB data described above. The halftone processed data is composed of, for example, 2-bit data for each pixel.

  A rasterization processing unit 1118 performs processing for changing matrix image data in the order of data to be transferred to the printer body 1. Thus, the rasterized data is output to the printer main body 1 as pixel data included in the print data.

<Settings of Printer Driver 1110>
FIG. 3 is an explanatory diagram of a user interface of the printer driver 1110. The user interface of the printer driver 1110 is displayed on the display device 1200 via the video driver 1102. A user can make various settings of the printer driver 1110 using the input device 1300.

  The user can select a print mode from this screen. For example, the user can select the high-speed print mode or the fine print mode as the print mode. Then, the printer driver 1110 converts the image data into print data so as to have a format corresponding to the selected print mode.

  Further, the user can select the print resolution (dot interval when printing) from this screen. For example, the user can select 720 dpi or 360 dpi as the print resolution from this screen. The printer driver 1110 performs resolution conversion processing according to the selected resolution, and converts the image data into print data.

  Further, the user can select a printing paper (medium) used for printing from this screen. For example, the user can select plain paper or glossy paper as the printing paper. If the paper type (paper type) is different, the ink bleeding and drying methods are also different, so the ink amount suitable for printing also differs. Therefore, the printer driver 1110 converts the image data into print data according to the selected paper type.

  As described above, the printer driver 1110 converts image data into print data in accordance with conditions set via the user interface. The user can make various settings of the printer driver 1110 from this screen, and can also know the remaining amount of ink in the cartridge.

=== Configuration of Printer Main Body 1 ===
FIG. 4 is a block diagram of the overall configuration of the printer main body 1 of the present embodiment. FIG. 5 is a perspective view showing the internal configuration of the printer main body 1 of the present embodiment. FIG. 6 is a longitudinal sectional view showing the internal configuration of the printer main body 1 of the present embodiment. Hereinafter, a basic configuration of the printer main body 1 of the present embodiment will be described.

  As shown in FIG. 4, the printer main body 1 of the present embodiment includes a transport unit 20, a carriage unit 30, a head unit 40, a sensor 50, and a controller 60. The printer main body 1 that has received print data from the computer device 1100 that is an external device controls each unit (conveyance unit 20, carriage unit 30, and head unit 40) by the controller 60. The controller 60 controls each unit based on the print data received from the computer apparatus 1100 and forms an image on the medium S. The situation in the printer main body 1 is monitored by a sensor 50, and the sensor 50 outputs a detection result to the controller 60. The controller 60 that has received the detection result from the sensor 50 controls the units 20, 30, and 40 based on the detection result.

  The transport unit 20 feeds the medium (for example, paper) S to a printable position and transports the medium S by a predetermined transport amount in a predetermined direction (hereinafter referred to as a transport direction or a vertical direction) during printing. It is. That is, the transport unit 20 functions as a transport mechanism that transports the medium S. As shown in FIG. 6, the transport unit 20 includes a paper feed roller 21, a transport motor 22 (also referred to as a PF motor), a transport roller 23, a platen 24, and a paper discharge roller 25. However, in order for the transport unit 20 to function as a transport mechanism, all of these components are not necessarily required. The paper feed roller 21 is a roller for automatically feeding the medium S inserted into the paper insertion slot into the printer main body 1. The paper feed roller 21 has a D-shaped cross-sectional shape, and the length of the circumferential portion is set to be longer than the transport distance to the transport roller 23, so the medium S is transported using this circumferential portion. It can be conveyed to the roller 23. The transport motor 22 is a motor for transporting the medium S in the transport direction, and is configured by a DC motor. The transport roller 23 is a roller that transports the medium S fed by the paper feed roller 21 to a printable area, and is driven by the transport motor 22. The platen 24 supports the medium S being printed. The paper discharge roller 25 is a roller for discharging the medium S on which printing has been completed to the outside of the printer main body 1. The paper discharge roller 25 rotates in synchronization with the transport roller 23.

  The carriage unit 30 is for moving the head 41 in a predetermined direction (hereinafter referred to as a carriage movement direction or a lateral direction). The carriage movement direction is orthogonal to the transport direction. As illustrated in FIG. 5, the carriage unit 30 includes a carriage 31 and a carriage motor 32 (also referred to as a CR motor). The carriage 31 can reciprocate in the carriage movement direction. (Thus, the head 41 moves along the carriage movement direction.) The carriage 31 detachably holds an ink cartridge 90 that stores ink. The carriage motor 32 is a motor for moving the carriage 31 in the carriage movement direction, and is constituted by a DC motor.

  The head unit 40 is for ejecting ink onto the medium S. The head unit 40 has a head 41. The head 41 has a plurality of nozzles as the color ink discharge portion of the present invention, and discharges ink intermittently from each nozzle. The head 41 is provided on the carriage 31. Therefore, when the carriage 31 moves in the carriage movement direction, the head 41 also moves in the carriage movement direction. Then, ink is intermittently ejected while the head 41 is moving in the carriage movement direction, so that a dot line (raster line) along the horizontal direction as the carriage movement direction is formed on the medium S.

  The sensor 50 includes a linear encoder 51 (see FIG. 5), a rotary encoder 52 (see FIG. 6), a paper detection sensor 53 (see FIG. 6), a paper width sensor 54 (see FIG. 6), and the like. The linear encoder 51 is for detecting the position of the carriage 31 in the carriage movement direction. The rotary encoder 52 is for detecting the rotation amount of the transport roller 23. The paper detection sensor 53 is for detecting the position of the leading edge of the medium S to be printed. The paper detection sensor 53 is provided at a position where the leading edge of the medium S can be detected while the paper supply roller 21 is feeding the medium S toward the transport roller 23. The paper detection sensor 53 is a mechanical sensor that detects the leading edge of the medium S by a mechanical mechanism. More specifically, the paper detection sensor 53 has a lever that can rotate in the paper transport direction, and this lever is disposed so as to protrude into the transport path of the medium S. Therefore, the leading edge of the medium S comes into contact with the lever, and the lever is rotated. Therefore, the paper detection sensor 53 detects the position of the leading edge of the medium S by detecting the movement of the lever. The paper width sensor 54 is attached to the carriage 31. The paper width sensor 54 is an optical sensor, and detects the presence or absence of the medium S by the light receiving unit detecting the reflected light of the light irradiated to the medium S from the light emitting unit. The paper width sensor 54 detects the position of the end of the medium S while moving by the carriage 41 and detects the width of the medium S. The paper width sensor 54 can also detect the leading edge of the medium S depending on the situation. Since the paper width sensor 54 is an optical sensor, the position detection accuracy is higher than that of the paper detection sensor 53.

  The controller 60 is a control unit (control means) for controlling the printer main body 1. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 is for transmitting and receiving data between the computer device 1100 as an external device and the printer main body 1. The CPU 62 is an arithmetic processing unit for controlling the entire printer body 1. The memory 63 is for securing an area for storing the program of the CPU 62, a work area, and the like, and has storage means such as a RAM and an EEPROM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

=== Head 41 ===
<About the configuration of the head 41>
FIG. 7 is an arrangement diagram of nozzles on the lower surface of the head 41. As shown in the drawing, a plurality of color ink nozzle groups 411Y, 411M, 411C, and 411K are provided on the lower surface of the head 41. In the present embodiment, the yellow ink nozzle group 411Y, the magenta ink nozzle group 411M, and the cyan ink nozzle for each color ink, that is, yellow (Y), magenta (M), cyan (C), and black (K), respectively. A group 411C and a black ink nozzle group 411K are provided. Each nozzle group 411Y, 411M, 411C, 411K includes a plurality of nozzles # 1 to # 180 (180 in this embodiment) for ejecting ink of each color.

  The plurality of nozzles # 1 to # 180 of each of the nozzle groups 411Y, 411M, 411C, and 411K are aligned at regular intervals (nozzle pitch: k · D) along the transport direction. Here, D is the minimum dot pitch in the carrying direction (that is, the interval at the highest resolution of dots formed on the paper S). K is an integer of 1 or more. For example, when the nozzle pitch is 180 dpi (1/180 inch) and the dot pitch in the transport direction is 720 dpi (1/720), k = 4.

  The nozzles # 1 to # 180 of the nozzle groups 411Y, 411M, 411C, and 411K are assigned lower numbers as the nozzles on the downstream side (# 1 to # 180). That is, the nozzle # 1 is located downstream of the nozzle # 180 in the transport direction. Further, the paper width sensor 54 is located at substantially the same position as the nozzle # 180 on the most upstream side with respect to the position in the paper transport direction. Each of the nozzles # 1 to # 180 is provided with a piezo element (not shown) as a drive element for driving the nozzles # 1 to # 180 to discharge ink.

<About driving the head>
FIG. 8 is an explanatory diagram of the drive circuit of the head unit 40. This drive circuit is provided in the unit control circuit 64 described above, and includes an original drive signal generation unit 644A and a drive signal shaping unit 644B, as shown in FIG. In the present embodiment, such drive circuits for the nozzles # 1 to # 180 are provided for each color ink nozzle group, that is, the yellow ink nozzle group 411Y, the magenta ink nozzle group 411M, the cyan ink nozzle group 411C, and the black ink nozzle. It is provided for each of the groups 411K, and the piezo elements are individually driven for each of the nozzle groups 411Y, 411M, 411C, and 411K. In the figure, the number in parentheses at the end of each signal name indicates the number of the nozzle to which the signal is supplied.

  When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezoelectric element, the piezoelectric element expands according to the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts in accordance with the expansion and contraction of the piezo element, and the ink amount corresponding to the contraction is discharged from the nozzles # 1 to # 180 of each color as ink.

The original drive signal generator 644A generates an original signal ODRV that is used in common by the nozzles # 1 to # 180. The original signal ODRV is a signal including a plurality of pulses within a period of one pixel (within a time during which the carriage 31 crosses the interval of one pixel).
The drive signal shaping unit 644B receives the original signal ODRV from the original drive signal generation unit 644A and the print signal PRT (i). The drive signal shaping unit 644B shapes the original signal ODRV according to the level of the print signal PRT (i), and outputs it as the drive signal DRV (i) toward the piezoelectric elements of the nozzles # 1 to # 180. The piezoelectric elements of the nozzles # 1 to # 180 are driven based on the drive signal DRV from the drive signal shaping unit 644B.

<About the drive signal of the head 41>
FIG. 9 is a timing chart for explaining each signal. In other words, the timing chart of each signal of the original signal ODRV, the print signal PRT (i), and the drive signal DRV (i) is shown in FIG.

  The original signal ODRV is a signal supplied in common to the nozzles # 1 to # 180 from the original drive signal generator 644A. In the present embodiment, the original signal ODRV includes two pulses of a first pulse W1 and a second pulse W2 within a period of one pixel (within a time during which the carriage crosses the interval of one pixel). The original signal ODRV is output from the original drive signal generation unit 644A to the drive signal shaping unit 644B.

  The print signal PRT is a signal corresponding to pixel data assigned to one pixel. That is, the print signal PRT is a signal corresponding to the pixel data included in the print data. In the present embodiment, the print signal PRT (i) is a signal having 2-bit information for one pixel. Note that the drive signal shaping unit 644B shapes the original signal ODRV according to the signal level of the print signal PRT and outputs the drive signal DRV.

  The drive signal DRV is a signal obtained by blocking the original signal ODRV according to the level of the print signal PRT. That is, that is, when the print signal PRT is 1 level, the drive signal shaping unit 644B passes the corresponding pulse of the original signal ODRV as it is as the drive signal DRV. On the other hand, when the print signal PRT is 0 level, the drive signal shaping unit 644B blocks the pulse of the original signal ODRV. The drive signal shaping unit 644B outputs the drive signal DRV to the piezo element provided for each nozzle. The piezo element is driven according to the drive signal DRV.

  When the print signal PRT (i) corresponds to the 2-bit data “01”, only the first pulse W1 is output in the first half of one pixel section. Thereby, a small ink droplet (hereinafter also referred to as a small ink droplet) is ejected from the nozzle, and a small dot (hereinafter also referred to as a small dot) is formed on the paper. When the print signal PRT (i) corresponds to the 2-bit data “10”, only the second pulse W2 is output in the latter half of one pixel section. As a result, medium-sized ink droplets (hereinafter also referred to as medium ink droplets) are ejected from the nozzles, and medium-sized dots (hereinafter also referred to as medium dots) are formed on the paper. When the print signal PRT (i) corresponds to the 2-bit data “11”, the first pulse W1 and the second pulse W2 are output in one pixel section. As a result, medium ink droplets and small ink droplets are continuously ejected from the nozzle, and the paper has large dots (hereinafter referred to as large dots) formed by combining the medium ink droplet landing marks and the small ink landing marks. Are also formed). When the print signal PRT (i) corresponds to the 2-bit data “00”, neither the first pulse W1 nor the second pulse W2 is output in one pixel section. As a result, no ink droplets of any size are ejected from the nozzles, and no dots are formed on the paper.

  As described above, the drive signal DRV (i) in one pixel section is shaped to have four different waveforms according to four different values of the print signal PRT (i).

=== Print processing ===
<Processing of Printer Driver 1110>
FIG. 10 is a flowchart for explaining the printing method of the present embodiment. Various operations described below are performed by the printer driver 1110.

  First, the printer driver 1110 receives a print command from the application program 1104 (S102). This print command is issued when the user commands printing on the application. This print command includes, for example, image data edited on an application.

  Next, the printer driver 1110 converts the image data included in the print command into RGB image data having a resolution of 720 dpi (horizontal) × 720 dpi (vertical) as an example of the print resolution (S104: resolution conversion). processing).

  Next, the printer driver 1110 converts RGB image data into CMYK image data (S106: color conversion process). In this embodiment, since the RGB image data has a resolution of 720 dpi (horizontal) × 720 dpi (vertical), the CMYK image data after the color conversion processing also has a resolution of 720 dpi (horizontal) × 720 dpi (vertical). Note that the CMYK image data after the color conversion process is CMYK data of 256 gradations.

  Next, the printer driver 1110 converts the CMYK image data of 256 gradations into data of 4 gradations with a resolution of 720 dpi (horizontal) × 720 dpi (vertical) using a dither method or the like (S108: halftone processing). . The 4-gradation data is 2-bit data assigned to each pixel. That is, 2-bit data of “00”, “01”, “10”, or “11” is assigned to each pixel, and a dot assigned to “00” as described above is assigned to each pixel. Are formed, and small dots, medium dots, and large dots are formed in pixels to which “01”, “10”, and “11” are assigned, respectively.

  Finally, the printer driver 1110 performs processing to change the generated 2-bit data in the order of data to be transferred to the printer main body 1, and creates print data (S110: rasterization processing). The generated print data is output to the printer main body 1.

<Operation of Printer Main Body 1>
The printer main body 1 executes print processing when print data is sent from the computer apparatus 1100. FIG. 11 is a processing flowchart of the printer main body 1 at this time. Each process described below is executed by the controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has a code for executing each process.

  Print Command Reception (S202): The controller 60 receives a print command from the computer apparatus 1100 via the interface unit 61. This print command is included in the header of print data transmitted from the computer apparatus 1100. Then, the controller 60 analyzes the contents of various commands included in the received print data, and performs the following paper feed processing, transport processing, ink ejection processing, and the like using each unit.

  Paper feed process (S204): First, the controller 60 performs a paper feed process. The paper feed process is a process of supplying paper to be printed into the printer main body 1 and positioning the paper at a print start position (also referred to as a cue position). The controller 60 rotates the paper feed roller 21 and sends the paper to be printed to the transport roller 23. The controller 60 rotates the transport roller 23 to position the paper fed from the paper feed roller 21 at the print start position. When the paper is positioned at the print start position, at least some of the nozzles of the head 41 are opposed to the paper.

  Dot Formation Processing (S206): Next, the controller 60 performs dot formation processing. The dot formation process is a process in which ink is intermittently ejected from a head that moves in the carriage movement direction to form a plurality of dots on the paper along the horizontal direction. The controller 60 drives the carriage motor 32 to move the carriage 31 in the carriage movement direction. Then, the controller 60 ejects ink from the head based on the print data while the carriage 31 is moving. When ink droplets ejected from the head land on the paper, dots are formed on the paper.

  Transport Process (S208): Next, the controller 60 performs a transport process. The conveyance process is a process of moving the paper relative to the head along the conveyance direction. The controller 60 drives the carry motor and rotates the carry roller 23 to carry the paper in the carrying direction. By this carrying process, the head 41 can form dots at positions different from the positions of the dots formed by the previous dot formation process.

  Paper discharge determination (S210): Next, the controller 60 determines whether or not to discharge the paper being printed. If there is still data to be printed on the paper being printed, no paper is discharged. Then, the controller 60 alternately repeats the dot formation process and the conveyance process until there is no data to be printed, and gradually prints an image composed of dots on paper. When there is no more data for printing on the paper being printed, the controller 60 discharges the paper. The controller 60 discharges the printed paper to the outside by rotating the paper discharge roller. The determination of whether or not to discharge paper may be based on a paper discharge command included in the print data.

  Print end determination (S212): Next, the controller 60 determines whether or not to continue printing. If printing is to be performed on the next paper, printing is continued and the paper feeding process for the next paper is started. If printing is not performed on the next paper, the printing operation is terminated.

=== Edge Processing for Smoothing the Outline of an Image ===
<Outline of edge processing>
In the printing system 1000 according to the present embodiment, edge processing can be performed on a contour portion of an image to be printed. This edge processing is processing for forming small dots in the adjacent region outside the contour portion of the image to be printed, and smoothing the contour of the image to make the image clear.

  For example, when the edge processing is not performed, as shown in FIG. 12A, the ink in the overlapping portion (see the horizontal stripe portion and the vertical stripe portion) of the large dots constituting the contour portion E is transferred to the adjacent region Ah, The ink protrudes in a bowl shape toward Av, and the outline appears to be macroscopically disturbed. On the other hand, if edge processing is performed, as shown in FIG. 12B, the protrusion of the ridge-like ink is hidden by the small dots formed in the adjacent areas Ah and Av, so that the contour of the image is macroscopic. To look smooth. Incidentally, square boxes in the figure indicate pixels that are the minimum unit of dot formation.

  The image to be subjected to the edge processing is mainly a text image such as a character or symbol that requires visibility. Therefore, in the present embodiment, when a text image is printed, edge processing is performed on the text image.

  The text image referred to here is, for example, an image formed based on text data composed of character codes such as ASCII codes, character codes including characters and symbols, control codes, and the like. It is. The text data includes document data created by various word processing software such as “Microsoft Word (product name)” and “Ichitaro (product name)”, a text editor, and the like. When printing is performed based on such text data, a character code such as a character code included in the text data is imaged as a character, a symbol, or the like with reference to font information provided in advance. . Therefore, the text image here can be said to be an image printed by such processing.

  In addition to such characters and symbols, the text image of this embodiment includes, for example, graphics created or edited by various CAD application software such as “Vector Works (product name)” and other application software. It may include graphics such as graphics formed on the basis of drawing data, and also includes graphics and graphs created or edited by various graphic creation functions and graph creation functions such as various word processors and spreadsheet application software. But it ’s okay.

  On the other hand, as an image that is not a target of edge processing in the present embodiment, for example, natural images such as photographic data taken with a digital camera or the like, and various images recorded by various still image storage methods such as JEPG and bitmap are used. Image data. However, it may be applied to such a natural image depending on the case. That is, it is not necessary to limit the edge processing target to a text image.

  A method for determining whether the image to be printed is a text image will be described in detail later.

<About edge processing of reference example>
First, the edge processing of the reference example will be described with reference to FIGS. 13A and 13B. FIG. 13A and FIG. 13B are diagrams showing a dot formation state of an image to be printed. Here, a case where a letter “T” is printed is illustrated. FIG. 13A shows the case without edge processing, and FIG. 13B shows the case with edge processing. Each square box in each figure represents a pixel which is the minimum unit of dot formation.

  Here, since the image “T” is a text image, it is basically composed of only large dots when no special processing is performed. That is, all the images “T” without edge processing shown in FIG. Consists of large dots.

  On the other hand, in the image “T” with edge processing shown in FIG. 13B, along the entire circumference of the contour portion of the image “T”, in order to hide the ink mist that protrudes outward from the contour portion described above, Small dots are formed in the outer adjacent area. Specifically, small dots are formed in adjacent pixels adjacent to the outside of the pixels constituting the contour portion. As a result, as described above, the ink ridge that protrudes to the adjacent pixels is hidden, so that the outline of the image looks macroscopically smooth.

  However, the edge processing of this reference example is based on the premise that the shape of a large dot is an ideally symmetrical shape such as a perfect circle as shown in FIG. 14A. That is, the upper left corner of the image “T” in FIG. 13A is enlarged and shown in FIG. 12A. If the large dots are symmetrical in the vertical and horizontal directions, the horizontal overlap of the large dots arranged in the horizontal direction (horizontal stripes) The vertical overlapping state of the large dots arranged in the vertical direction (see the vertical stripe portion) is not different from each other, and the adjacent regions Ah and Av outside the contour portion E have a horizontal contour. Regardless of the portion Eh and the vertical contour portion Ev, almost the same amount of ink overflows.

  As a result, in the adjacent region Ah of the horizontal contour portion Eh and the adjacent region Av of the vertical contour portion Ev, the same extent of the ridge-like protruding portion occurs, and the contour of the image is disturbed to the same extent. In order to hide these disturbances regardless of the direction and the horizontal direction, as shown in FIGS. 12B and 13B, small dots are formed over the entire circumference of the contour portion of the image “T”.

  However, the large dot shape of the printing apparatus according to the present embodiment is a horizontally long shape that is longer in the horizontal direction than in the vertical direction, as shown in FIG. 14B. This is because, as described above, the large dots are formed by continuously ejecting medium ink droplets and small ink droplets from the nozzles while moving the carriage 31 in the lateral direction that is the carriage movement direction. This is because the large dot is formed by combining the landing trace of the medium ink droplet and the landing trace of the small ink droplet formed on the side of the landing trace, as shown in FIG. 14C.

  In the case of such a horizontally long shape, the horizontal contour is more disturbed than the vertical contour, and the vertical and horizontal anisotropy is provided with respect to the contour disturbance. FIG. 15 is an explanatory diagram of the cause of this anisotropy. Like FIG. 12A, the upper left corner of the image “T” in FIG. 13A is enlarged, but as shown in FIG. In addition, the outline in the vertical direction is smooth without being disturbed, but the outline in the horizontal direction is disturbed, and this is caused by the fact that the shape of the large dot is a horizontally long shape.

  More specifically, the horizontal contour portion Eh is formed by driving a large dot into each pixel adjacent in the horizontal direction. Each large dot has a horizontally long shape. Accordingly, the large dots formed in the pixels adjacent to each other horizontally overlap each other, and the ink in the overlapping portion (see the horizontal stripe portion) overflows in the vertical direction and is adjacent to the outside in the vertical direction. It tends to protrude into the adjacent area Ah like a bowl, and as a result, its outline is disturbed and lacks smoothness.

  On the other hand, the vertical contour portion Ev is formed by implanting large dots in each pixel adjacent in the vertical direction, but here, it is formed in pixels adjacent to each other vertically. The large dots overlap each other small because the shape is horizontally long. Therefore, the ink in the overlapping portion (see the vertical stripe portion) hardly protrudes into the adjacent area Av adjacent to the outside in the horizontal direction, and its outline is macroscopically relatively undisturbed compared to the horizontal outline portion Eh. It will look smooth.

  Then, when the edge processing of the reference example is applied to such a printing apparatus that has vertical and horizontal anisotropy in such a disturbance state of the contour portion E, the vertical direction contour portion with less image contour disturbance Up to Ev, unnecessary small dots are formed in the adjacent area Av outside the Ev, so that ink is wasted.

  Therefore, in the printing apparatus according to the present embodiment, small dots are formed along the horizontal contour portion Eh in the adjacent region Ah outside the horizontal contour portion Eh, but outside the vertical contour portion Ev. Small dots are not formed in the adjacent area Av. This prevents the formation of useless small dots that do not contribute much to smoothing the contour of the image, and effectively prevents wasteful consumption of ink.

<About the edge processing according to the present embodiment>
FIG. 16A is a diagram showing a dot formation state to be formed based on the image data of the image “T” before the edge processing, which is the same as FIG. 13A without the edge processing described above. FIG. 16B is a diagram showing a formation state of dots to be formed based on the image data after performing the edge processing according to the present embodiment.

  As described above, the image “T” before the edge processing in FIG. 16A is composed of only large dots. On the other hand, after the edge processing of the present embodiment, as shown in FIG. 16B, in addition to the image “T” before the edge processing, small dots appear in the adjacent region Ah outside the lateral contour portion Eh. Are formed, but small dots are not formed in the adjacent area Av outside the vertical contour portion Ev. This is because, as described above, since the large dot has a horizontally long shape, the outline disturbance mainly occurs in the horizontal direction outline portion Eh and hardly occurs in the vertical direction outline portion Ev.

<Specific processing procedure of edge processing>
Here, a specific processing procedure of edge processing will be described. Hereinafter, a case where edge processing is performed on the image data of the image “T” in FIG. 16A described above will be described as an example.

  This edge processing is performed by a printer driver 1110 installed in the computer apparatus 1100. The printer driver 1110 performs this edge processing between the halftone processing and rasterization processing described above (FIG. 2 or FIG. 10). See). That is, the printer driver 1110 performs edge processing described below on the image data (2-bit data) after halftone processing, and performs rasterization processing on the image data (2-bit data) after the edge processing. Go to create print data.

  FIG. 17 is a flowchart showing the processing procedure of edge processing. 18A to 18D are explanatory diagrams illustrating changes in the state of image data due to edge processing. FIG. 19 shows a small dot generation determination filter used for edge processing.

  First, in step S302, the large dot pixel data “11” on the halftone processed image data is replaced with “1”, and the other pixel data is replaced with “0”. As a result, the image data is changed from the state shown in FIG. 18A to the state shown in FIG. 18B.

  In the next step S304, a small dot generation determination filter is applied to the image data in FIG. 18B to extract pixel data that should generate a small dot.

  The extraction process will be described in detail. The small dot generation determination filter is a 3 × 3 matrix as shown in FIG. 19, and each square corresponds to each pixel of the image data, and is positioned at the center thereof. The square to correspond to the target pixel of this extraction process. Then, after multiplying the pixel data of the pixel of interest and the surrounding eight pixels by the numerical values of the corresponding cells, all the multiplied values are added to obtain the calculated value for the pixel of interest. For example, if the coordinate of the pixel of interest is (i, j) and the pixel data is F (i, j), the calculated value Value (i, j) of the pixel of interest (i, j) is as follows. Desired.

Value (i, j) = (0) × F (i−1, i−1) + (−1) × F (i, j−1) + (0) × F (i + 1, j−1) + ( −2) × F (i, j−1) + (7) × F (i, j) + (−2) × F (i + 1, j) + (0) × F (i−1, j + 1) + ( −1) × F (i, j + 1) + (0) × F (i + 1, j + 1)
Then, the calculated value Value (i, j) is obtained for all the pixel data on the image data, and the corresponding calculated value is recorded in each pixel data on the image data as shown in FIG. 18C.

  In the final step S306, referring to the determination value table shown in FIG. 20, each pixel data on the image data in FIG. 18C is sequentially replaced with 2-bit data corresponding to the calculated value and recorded. That is, large dot data “11” is recorded for pixel data having a calculated value of 1 or more, and small dot data “01” is recorded for pixel data having a calculated value of −1 or −3. For the pixel data having a calculated value other than these, the dotless data “00” is recorded.

  FIG. 18D shows the state of the image data after executing step S306. In the adjacent pixel Pv outside the vertical contour portion Ev, data “00” without dots is recorded, and the horizontal contour portion is displayed. Small dot data “01” is recorded in the adjacent pixel Ph outside Eh.

  The specific processing procedure of the edge processing has been described above. Here, the reason why the “calculation values for forming small dots” in the determination value table of FIG. 20 are only −1 and −3. A supplementary explanation will be given with reference to FIGS. 21A and 21B. FIG. 21A and FIG. 21B show pixel data corresponding to the vicinity of the contour in the image data before edge processing, extracted in a 3 × 3 matrix, and each cell is a pixel. Further, “1” and “0” in the grid indicate data of large dots and no dots, respectively. In addition, as described above, it is assumed that the center cell of the matrix in the figure is the pixel of interest.

  First, whether or not to form a small dot on a target pixel is determined by whether or not the target pixel is an adjacent pixel outside the lateral contour portion. For this reason, considering a mode in which this pixel of interest can be an adjacent pixel outside the lateral contour portion, this mode corresponds to a case in which large dots exist either above or below the pixel of interest in the vertical direction. In these cases, the embodiments (a-1) to (a-20) shown in FIG. 21A and the embodiments (b-1) to (b-23) shown in FIG. 21B can be mentioned. Then, when the calculation value Value of the pixel of interest is calculated for each of these modes, −1, −2, −3, −4, −5, and −6 are obtained. Value).

  However, in these modes, horizontal long dots are formed on both sides in the vertical direction across a blank portion of one dot as shown in FIG. 21B (modes (b-1) to (b-11) and Aspects (refer to aspects (b-16) to (b-18)) and aspects in which horizontally long dots are formed on both sides in the lateral direction across a blank portion for one dot (aspects (b-12) to (b) -15) and embodiments (b-19) to (b-23)). If a small dot is generated even in such a blank portion of interest, the blank portion is completely filled, and a part of the image is crushed so that it is difficult to visually recognize.

  Therefore, for such modes (b-1) to (b-23), the calculation values are -2, -4, -5, -6 so as not to form small dots in the blank portions. Is excluded from the “calculated value for forming small dots”, and as a result, as shown in the determination value table of FIG. 20, the “calculated value for forming small dots” is only −1 and −3. It is.

  Note that according to the small dot generation determination filter and the determination value table, small dots are also formed in the modes (a-9) to (a-14) in FIG. In addition, small dots are also formed in the adjacent area outside the oblique contour portion inclined in the oblique direction.

<Determining whether the image is a text image>
The printer driver 1110 determines whether the image to be printed is a text image. As shown in FIG. 10, the printer driver 1110 performs resolution conversion processing (S104) and color conversion processing (S106) on the image data received from the application program 1104. Based on the CMYK image data after the color conversion processing, printing is performed. It is determined whether the image to be tried is a text image.

  Specifically, the printer driver 1110 refers to data of each color of cyan (C), magenta (M), yellow (Y), and black (K) from the generated CMYK image data, and other than black (K). It is checked whether the data of each color of cyan, that is, cyan (C), magenta (M), and yellow (Y) are all composed of data having no color, that is, “white” gradation. When data of colors other than black (K), that is, data of each color of cyan (C), magenta (M), and yellow (Y) are all composed of data indicating a gradation of “white”. Next, it is checked whether all the data indicating the color state in the black (K) data is data indicating a predetermined gradation. The data indicating the predetermined gradation here is data indicating the darkest color among the 256 gradation colors represented by black (K). For example, data such as “0” and “255”. This is because in the present embodiment, only the darkest color of black (K) is used for printing text images in order to clearly print characters, symbols, and the like. Since only the dark color is used for printing the text image, it is possible to check whether the data indicating the state of the color included in the black (K) data is all data indicating a predetermined gradation. It is possible to easily determine whether the image to be printed is a text image.

  FIG. 22 is a flowchart of a process for determining whether or not the image is a text image.

  First, in step S402, the printer driver 1110 acquires CMYK image data, and checks whether the cyan (C) data includes data other than data indicating a color state, that is, data indicating “white”. . If it is included, it is determined that the image to be printed is an image other than the text image, and the process is terminated (S416). On the other hand, if the cyan (C) data is all in a state having no color, that is, data indicating “white”, the process proceeds to the next step S406.

  In step S406, the magenta (M) data is checked in the same manner as described above. If it is included, it is determined that the image to be printed is an image other than the text image, and the process is terminated (S416). On the other hand, if the magenta (M) data is all in a state having no color, that is, data indicating “white”, the process proceeds to the next step S408.

  Thereafter, in step S408, the same check as above is performed for yellow (Y) data, and in step S410, black (K) data.

  Here, if all of the black (K) data indicate “white”, it is determined that an error has occurred, and the process returns to step S402 to repeat the process from the beginning. On the other hand, if the black (K) data includes data other than the data indicating “white”, the process proceeds to step S412 and the black (K) data indicates data indicating a predetermined gradation. It is checked whether it is constituted only by. That is, it is checked whether or not the black (K) data is composed of only the data having the darkest color among the 256 gradations. If the black (K) data is composed only of data indicating a predetermined gradation, it is determined that the image to be printed is a text image (S414). On the other hand, if the black (K) data includes data indicating gradations other than the predetermined gradation (excluding data indicating “white” gradation), the image to be printed is text. It is determined that the image is not an image (S416), and the process ends.

  Note that colors other than black (K), that is, here cyan (C), magenta (M), and yellow (Y) have been examined in the above-described order. You can check in a different order.

  In addition, when there are a plurality of types of black (K), it is determined whether or not black (K) used for printing a text image among the plurality of types of black (K) is configured by only predetermined data. Good. When ink of a color other than black (K) is used for printing a text image, it is preferable to determine whether or not the color is constituted only by predetermined data.

=== Other Embodiments ===
As described above, the printing apparatus such as a printer according to the present invention has been described based on one embodiment. However, the above-described embodiment is for facilitating the understanding of the present invention, and the present invention is limited and interpreted. Not meant to be The present invention can be changed or improved without departing from the gist thereof, and needless to say, the present invention includes equivalents thereof. In particular, even the embodiments described below are included in the printing apparatus according to the present invention.

  In the present embodiment, part or all of the configuration realized by hardware may be replaced by software, and conversely, part of the configuration realized by software may be replaced by hardware.

  In addition, a part of the processing performed on the printing apparatus side may be performed on the host side (computer apparatus 1100 side), and a dedicated processing apparatus is provided between the printing apparatus and the host, and this processing apparatus. A part of the processing may be performed at.

<About printing devices>
In the present embodiment, an ink jet printer that ejects ink using a piezo element is illustrated. However, the present invention is not limited to this as long as it is a printer that ejects ink. For example, a bubble jet printer may be used.

<About dot size types>
In the above-described printing apparatus, there are three types of dot sizes to be formed: small dots, medium dots, and large dots. However, the present invention is not limited to such cases, and the type of size is not limited to this. There may be four or more types, or two types.

<Small dot generation determination filter used for edge processing>
In the above-described embodiment, the small dot generation determination filter used for edge processing is a 3 × 3 matrix filter, but is not limited to this, and may be a 4 × 4 or more matrix filter. Needless to say, the numerical value of each square in the filter matrix may be changed as appropriate in relation to the numerical value of the determination value table.

<Dots formed in the adjacent region outside the lateral contour portion>
In the above-described embodiment, the dots formed in the adjacent region Ah outside the horizontal contour portion Eh are small dots. However, if the dots are smaller than the horizontally long dots constituting the contour portion of the image, the size of the dots is For example, medium dots may be formed. However, when medium dots are used, if there is a large amount of overflowing from the overlapping portion of the horizontally long dots to the adjacent area Ah, the ridge-like protrusion of the adjacent area Ah is promoted and the outline is disturbed. There is a risk of letting you.

<Images subject to edge processing>
In the above-described embodiment, only the text image is the target of the edge processing. However, in the present invention, not only such an image but also an image other than the text image may be the target of the edge processing. Specifically, for example, an image including a character image, for example, an image including a natural image such as a photograph in which a text image such as a character is incorporated may be a target of edge processing. In this case, it is preferable to perform edge processing only on the text image portion included in the natural image.

<About the printer driver 1110>
According to the above-described embodiment, the printer driver 1110 on the computer apparatus 1100 side performs edge processing. However, the edge processing is not limited to the printer driver 1110. For example, the present embodiment If the program for realizing the functions necessary for performing the edge processing is stored in various storage units such as the memory of the printer body 1, the printer body 1 can perform the edge processing described above. is there.

<About media>
As for the media, the above-mentioned paper includes plain paper, matte paper, cut paper, glossy paper, roll paper, paper, photographic paper, roll type photographic paper, etc. In addition to these, films such as OHP film and glossy film It may be a material, a cloth material, a metal plate material, or the like. That is, any medium can be used as long as it can be an ink ejection target.

1 is an explanatory diagram illustrating an example of an external configuration of a printing system 1000. FIG. 3 is a schematic explanatory diagram of basic processing performed by a printer driver 1110. FIG. 6 is an explanatory diagram of a user interface of a printer driver 1110. FIG. 1 is a block diagram of an overall configuration of a printer main body 1 according to an embodiment. 1 is a perspective view illustrating an internal configuration of a printer main body 1 according to an embodiment. 1 is a longitudinal sectional view showing an internal configuration of a printer main body 1 according to an embodiment. 4 is an arrangement diagram of nozzles on the lower surface of a head 41. FIG. 4 is an explanatory diagram of a drive circuit of a head unit 40. FIG. It is a timing chart for explanation of each signal. It is a flowchart for demonstrating the printing method of this embodiment. It is a flowchart of the process at the time of printing. FIG. 12A is an explanatory diagram when there is no edge processing, and FIG. 12B is an explanatory diagram when there is edge processing. 13A and 13B are diagrams showing the dot formation state of an image to be printed. FIG. 13A shows a case without edge processing, and FIG. 13B shows a case with edge processing of a reference example. Show. FIGS. 14A to 14C are diagrams showing the shape of a large dot. FIG. 14A shows an ideal shape premised on the edge processing of the reference example, and FIGS. 14B and 14C show the present embodiment. The actual shape which the printing apparatus of a form forms is shown. It is explanatory drawing of the cause which has the anisotropy regarding the aspect in the disorder | damage | failure state of the outline of an image. FIG. 16A and FIG. 16B are both diagrams showing the formation state of dots to be formed based on the image data of the image “T”. In FIG. 16A, the dots are formed based on the image data before edge processing. FIG. 16B shows a case where the image is formed based on the image data after the edge processing according to the present embodiment. It is a flowchart which shows the process sequence of the edge process which concerns on this embodiment. It is explanatory drawing which shows the state change of the image data by the said edge process. It is explanatory drawing which shows the state change of the image data by the said edge process. It is explanatory drawing which shows the state change of the image data by the said edge process. It is explanatory drawing which shows the state change of the image data by the said edge process. It is a figure which shows the small dot generation | occurrence | production determination filter used for the said edge process. It is a figure which shows the judgment value table used for the said edge process. It is a figure for supplementary explanation about "calculation value which should form a small dot" in a judgment value table. It is a figure for supplementary explanation about "calculation value which should form a small dot" in a judgment value table. It is a flowchart of the determination process whether an image is a text image.

Explanation of symbols

1 Printer body
20 transport unit, 21 paper feed roller, 22 transport motor (PF motor),
23 transport roller, 24 platen, 25 discharge roller,
30 carriage unit, 31 carriage,
32 Carriage motor (CR motor),
40 head units, 41 heads,
411Y yellow ink nozzle group, 411M magenta ink nozzle group,
411C cyan ink nozzle group, 411K black ink nozzle group,
50 sensors, 51 linear encoders, 52 rotary encoders,
53 Paper detection sensor, 54 Paper width sensor,
60 controller, 61 interface unit, 62 CPU,
63 memory, 64 unit control circuit,
64A original drive signal generation unit, 64B drive signal shaping unit,
1100 Computer device, 1102 Video driver,
1104 Application program, 1110 Printer driver,
1112 resolution conversion processing unit, 1114 color conversion processing unit,
1116 halftone processing unit, 1118 rasterization processing unit,
1200 display device, 1201 display,
1300 input device, 1300A keyboard, 1300B mouse,
1400 recording / reproducing apparatus, 1400A flexible disk drive apparatus,
1400B CD-ROM drive device,
1000 printing system,
Ah Adjacent region outside the lateral contour portion, Av Adjacent region outside the vertical contour portion,
E contour portion, Eh horizontal contour portion, Ev vertical contour portion,
Ph Adjacent pixels outside the horizontal contour portion, Pv Adjacent pixels outside the vertical contour portion

Claims (14)

(A) a nozzle for ejecting ink toward a medium to form dots and printing an image;
(B) A controller that determines the positions where the dots are to be formed while defining the positions in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is configured by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal region in the adjacent region outside the horizontal contour portion along the horizontal direction is included in the horizontal portion. A small dot smaller than the horizontally long dot is formed along the direction contour portion, and a dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. With the controller to avoid,
A printing apparatus comprising (C). The printing apparatus according to claim 1,
Do not form dots in the adjacent area outside the vertical contour portion,
The printing apparatus, wherein the small dots are formed in an adjacent region outside the vertical outline portion. The printing apparatus according to claim 1 or 2,
The printing apparatus is characterized in that when a horizontally long dot is formed on both sides in the vertical direction across a blank portion of one dot, no small dot is formed in the blank portion. The printing apparatus according to any one of claims 1 to 3,
The printing apparatus is characterized in that, when a horizontally long dot is formed on both sides in the horizontal direction across a blank portion of one dot, a small dot is not formed in the blank portion. The printing apparatus according to any one of claims 1 to 4,
The printing apparatus according to claim 1, wherein the small dot is a dot of a minimum size among dots formed by the nozzle. The printing apparatus according to any one of claims 1 to 5,
The printing apparatus according to claim 1, wherein the horizontally long dots are dots of a maximum size among the dots formed by the nozzles. The printing apparatus according to any one of claims 1 to 6,
The image is a text image;
The printing apparatus according to claim 1, wherein all the horizontally long dots of the image have the same size. The printing apparatus according to any one of claims 1 to 7,
The size of the overlapping part of the horizontally long dots adjacent in the horizontal direction is larger than the size of the overlapping part of the horizontally long dots adjacent in the vertical direction. The printing apparatus according to any one of claims 1 to 8,
The nozzle ejects ink while moving in the lateral direction,
The small dots are formed by landing a drop of ink ejected from the nozzle on the medium, and the horizontal dots are formed by a plurality of drops of ink ejected from the nozzle continuously on the medium. A printing apparatus characterized by being formed. (A) a nozzle for ejecting ink toward a medium to form dots and printing an image;
(B) A controller that determines the positions where the dots are to be formed while defining the positions in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is configured by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal region in the adjacent region outside the horizontal contour portion along the horizontal direction is included in the horizontal portion. A small dot smaller than the horizontally long dot is formed along the direction contour portion, and a dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. With the controller to avoid,
A printing apparatus comprising (C),
Do not form dots in the adjacent area outside the vertical contour portion,
In the adjacent area outside the vertical contour portion, the small dots are formed,
When a horizontally long dot is formed on both sides of the vertical direction across a blank portion of one dot, a small dot is not formed in the blank portion,
The printing apparatus is characterized in that, when a horizontally long dot is formed on both sides in the horizontal direction across a blank portion of one dot, a small dot is not formed in the blank portion.
The small dot is a dot of the smallest size among the dots formed by the nozzle,
The horizontally long dot is a dot of the maximum size among the dots formed by the nozzle,
The image is a text image;
The horizontally long dots in the image are all the same size,
The size of the overlapping portion between the horizontally long dots adjacent in the horizontal direction is larger than the size of the overlapping portion between the horizontally long dots adjacent in the vertical direction,
The nozzle ejects ink while moving in the lateral direction,
The small dots are formed by landing a drop of ink ejected from the nozzle on the medium, and the horizontal dots are formed by a plurality of drops of ink ejected from the nozzle continuously on the medium. A printing apparatus characterized by being formed. (A) a nozzle for ejecting ink toward a medium to form dots and printing an image;
(B) A controller that determines the positions where the dots are to be formed while defining the positions in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is configured by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal region in the adjacent region outside the horizontal contour portion along the horizontal direction is included in the horizontal portion. A small dot smaller than the horizontally long dot is formed along the direction contour portion, and a dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. With the controller to avoid,
A printing system comprising (C). In a printing control apparatus for controlling a printing apparatus having nozzles for ejecting ink toward a medium to form dots and printing an image,
When the printing control device determines the positions where dots should be formed in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is constituted by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal direction in the adjacent region outside the horizontal contour portion along the horizontal direction in the contour portion. A small dot smaller than the horizontally long dot is formed along the contour portion, and no dot is formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. A printing control apparatus characterized by comprising: In a printing method for printing an image by ejecting ink toward a medium to form dots,
When determining the position where the dot is to be formed while defining the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is constituted by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal direction in the adjacent region outside the horizontal contour portion along the horizontal direction in the contour portion. A small dot smaller than the horizontally long dot is formed along the contour portion, and a dot is not formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion. A printing method characterized by comprising: A program that is executed in a printing apparatus that includes nozzles for ejecting ink toward a medium to form dots and print an image,
When deciding the position where dots should be formed in the vertical and horizontal directions orthogonal to each other,
When the contour portion of the image is constituted by a plurality of horizontally long dots that are longer in the horizontal direction than in the vertical direction, the horizontal direction in the adjacent region outside the horizontal contour portion along the horizontal direction in the contour portion. A step of forming small dots smaller than the horizontally long dots along the contour portion;
And a step of preventing a dot from being formed in an adjacent region outside the vertical contour portion along the vertical direction in the contour portion.