JP2002240262A - Print technology for altering contour representation depending on print mode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for smoothing the contour of a print image in the printing of a text, or the like, while avoiding deterioration of the image quality of a photograph, or the like. SOLUTION: Since smoothing is performed in the printer only when a text print mode is selected depending on a print mode selected by a user, contour of a print image can be smoothed in the printing of a text while avoiding deterioration in the print image quality of a photograph due to smoothing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for printing by discharging ink droplets, and more particularly to a technique for smoothing an image.

[0002]

2. Description of the Related Art In recent years, as an output device of a computer,
A color printer that discharges several colors of ink from a head is widely used. In such a color printer, generally, the image data is digital data, and the print image is also a digital image. In such a digital image output, serrations (referred to as jaggies) are generated in the oblique contour, and therefore, smoothing processing (also referred to as anti-aliasing processing) for smoothing the jaggies is performed.

[0003]

However, when such a smoothing process is performed, for example, when the image to be printed is a binary image such as a text, the printing becomes clear while the image to be printed is a binary image such as a photograph. If performed in the case of a multi-valued image, there is a problem that the print image quality is rather deteriorated.

The present invention has been made to solve such a problem, and provides a technique capable of smoothing the outline of a printed image in text printing while avoiding deterioration in print quality of a photograph. The purpose is to do.

[0005]

In order to solve at least a part of the above problems, a first configuration of the present invention is to form dots by ejecting ink droplets from a print head. A printing device that performs printing,
A print mode that allows the user to select one of a plurality of print modes including a specific text print mode suitable for printing a text document and a photo print mode suitable for printing a photographic image The selection unit performs a smoothing process for smoothing an outline included in a print image when the specific text print mode is selected, and performs the smoothing process when the photo print mode is selected. And a smoothing processing unit.

In the first configuration of the present invention, the smoothing process is performed only when a specific text print mode is selected according to the print mode selected by the user. On the contrary, it is possible to smooth the outline of the printed image by smoothing processing in printing text while avoiding the deterioration of the print image quality of a photograph whose image quality is deteriorated.

[0007] In the above printing apparatus, further, each nozzle is used to form a different pixel size N in a pixel area on a print medium.
A print head drive unit capable of selectively forming any one of the types (N is an integer of 2 or more) of dots, and print data representing a dot formation state in each pixel according to the selected print mode. And a print data generation unit for generating
When the specific text print mode is selected, the print data generation unit configures the print data with binary pixel values indicating whether or not dots are formed in each pixel, while the photo mode is When selected, the print data is composed of multi-valued pixel values representing the dot formation state of each pixel, and the smoothing processing unit is configured to select each of the specific text print modes when the selected mode is selected. Which one of the N types of dots is to be formed in a pixel is determined in accordance with the binary pixel value of each pixel and the binary pixel value of a pixel adjacent to each pixel. Is preferred.

In this configuration, the function of selectively forming any one of a plurality of types of dots having different sizes in one pixel area is provided for smoothing contours in text printing and improving image quality in photographic image printing. And can be used for both.

In the above printing apparatus, the print head drive section can form dots of different sizes by ejecting ink droplets to a plurality of different positions within a one-pixel area on a print medium. When the specific text print mode is selected, the discharge position of the ink droplet in the area of each pixel is determined by the binary pixel value of each pixel and the binary pixel value of a pixel adjacent to each pixel. It is preferable to determine according to the pixel value.

This configuration has the advantage that the contour of the printed image can be further smoothed by selecting an appropriate ink droplet ejection position.

In the above printing apparatus, the print mode parameters that can be selected by the user include an ink color, and when the text print mode using the color ink is selected, the smoothing processing unit determines whether or not each of the inks of each color It is preferable to perform the above-mentioned smoothing process.

In some cases, the ejection positions of the ink droplets for smoothing the contour line differ depending on the type of print medium.
In such a case, by changing the content of the smoothing process according to the print medium, it is possible to perform the smoothing process suitable for the print medium.

In the above printing apparatus, the print mode parameters that can be selected by the user include an ink color, and when the text print mode using the color ink is selected, the printing mode parameter is set for each color ink. It is preferable to perform the above-mentioned smoothing process.

This has the advantage that the outline of the printed image can be smoothed not only for black text but also for color text.

According to a second aspect of the present invention, in order to perform printing using a printing unit that performs printing by ejecting ink droplets from a print head to form dots, print data to be supplied to the printing unit is provided. A print control device for generating
A print mode that allows the user to select one of a plurality of print modes including a specific text print mode suitable for printing a text document and a photo print mode suitable for printing a photographic image A selection unit configured to generate print data including smoothing process command information for causing the printing unit to perform a smoothing process for smoothing an outline included in a print image when the specific text print mode is selected; A print data generating unit that generates print data that does not include the smoothing processing command information when the photo print mode is selected.

In the second configuration of the present invention, print data including smoothing processing command information is generated in accordance with the printing mode selected by the user, and the smoothing processing command information performs smoothing processing on the printing unit. Since this information is information to be printed, this configuration can also smooth out the outline of the printed image by smoothing processing in text printing while avoiding deterioration in image quality in photo printing, as in the first configuration.

According to a third aspect of the present invention, there is provided a printing apparatus for performing printing by ejecting ink droplets from a print head to form dots in accordance with given print data, wherein the print data comprises: When including smoothing processing command information indicating that smoothing processing for smoothing the contours included in the print image should be performed, the smoothing processing is performed, and when not including the smoothing processing command information, the A smoothing processing unit that does not perform the smoothing processing is provided.

In the third configuration of the present invention, whether or not to perform the smoothing processing is determined according to whether or not the smoothing processing instruction information is included in the given print data. Since the information is information included in the print data according to the print mode, the same effect as in the first structure can be obtained with this structure.

The present invention can be realized in various modes, for example, a printing method and a printing apparatus,
Print control method and print control device, computer program for realizing functions of those methods or devices,
The present invention can be realized in the form of a recording medium on which the computer program is recorded, a data signal including the computer program and embodied in a carrier wave, and the like.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described based on examples in the following order. A. Device configuration: First Embodiment: C. First Embodiment Second embodiment D. Third embodiment: Example of smoothing process: Modification:

A. FIG. 1 is a block diagram showing the configuration of a printing system according to an embodiment of the present invention. The printing system includes a computer 90 as a print control device, a color printer 20 as a printing unit,
It has. Note that the combination of the color printer 20 and the computer 90 can be called a “printing device” in a broad sense.

In the computer 90, the application program 9 is executed under a predetermined operating system.
5 is working. A video driver 91 and a printer driver 96 are incorporated in the operating system, and print data PD to be transferred to the color printer 20 is output from the application program 95 via these drivers. The application program 95 performs a desired process on the image to be processed, and displays the image on the CRT 21 via the video driver 91.

When the application program 95 issues a print command, the printer driver 9 of the computer 90
6 receives the image data from the application program 95 and converts it into print data PD to be supplied to the color printer 20. In the example shown in FIG. 1, a resolution conversion module 97, a color conversion module 98, a halftone module 99, a rasterizer 100, a color conversion table L
A UT, a print mode selection unit 101, and a smoothing processing determination unit 102 are provided.

The resolution conversion module 97 serves to convert the resolution of the color image data handled by the application program 95 (ie, the number of pixels per unit length) into a resolution that can be handled by the printer driver 96. The image data whose resolution has been converted in this way is still image information consisting of three colors of RGB. The color conversion module 98 converts the RGB image data into multi-tone data of a plurality of ink colors that can be used by the color printer 20 for each pixel while referring to the color conversion table LUT.

The color-converted multi-tone data is, for example, 25
It has six gradation values. The halftone module 99 disperses and forms the ink dots,
The color printer 20 executes a halftone process for expressing this gradation value. The halftone-processed image data is sent to the color printer 2 by the rasterizer 100.
The data is rearranged in the order of data to be transferred to 0 and output as final print data PD. The print data PD
Includes raster data indicating the dot recording state during each main scan, and data indicating the sub-scan feed amount. In addition,
The functions of the print mode selection unit 101 and the smoothing process determination unit 102 will be described later.

The four modules 97 to 100 of the printer driver 96 correspond to a program for realizing the function of generating the print data PD. A program for realizing the function of the printer driver 96 is as follows.
It is supplied in a form recorded on a computer-readable recording medium. Examples of such a recording medium include a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punched card, a printed matter on which a code such as a barcode is printed, and an internal storage device of a computer (such as a RAM or a ROM). Various computer-readable media, such as memory and external storage, can be used.

FIG. 2 is a schematic configuration diagram of the color printer 20. The color printer 20 includes a sub-scan feed mechanism that conveys the printing paper P in the sub-scan direction by a paper feed motor 22 and a main scan feed that reciprocates the carriage 30 in the axial direction (main scan direction) of the platen 26 by the carriage motor 24. Mechanism, a head drive mechanism that drives a print head unit 60 (also referred to as a “print head assembly”) mounted on the carriage 30 to control ink ejection and dot formation, and a paper feed motor 22 and a carriage motor 24, print head unit 60 and operation panel 32
And a control circuit 40 for exchanging signals with the control circuit 40. The control circuit 40 is connected to the computer 90 via the connector 56.

The sub-scan feed mechanism for conveying the printing paper P is
A gear train (not shown) for transmitting the rotation of the paper feed motor 22 to the platen 26 and a paper transport roller (not shown) is provided. The main scanning feed mechanism for reciprocating the carriage 30 includes an endless drive belt 36 provided between the carriage motor 24 and a slide shaft 34 erected in parallel with the axis of the platen 26 and slidably holding the carriage 30. And a position sensor 39 for detecting the origin position of the carriage 30.

FIG. 3 is a block diagram showing the configuration of the color printer 20 with the control circuit 40 at the center. The control circuit 40 includes a CPU 41 and a programmable ROM (PRO
M) 43, a RAM 44, and a character generator (CG) 45 storing a character dot matrix. The control circuit 40 further includes an I / F dedicated circuit 50 dedicated to interface with an external motor or the like, and a head connected to the I / F dedicated circuit 50 to drive the print head unit 60 to eject ink. A drive circuit 52 and a motor drive circuit 54 for driving the paper feed motor 22 and the carriage motor 24 are provided. The I / F dedicated circuit 50 has a built-in parallel interface circuit.
6, the print data PD supplied from the computer 90 can be received. The color printer 20
Printing is performed according to the print data PD. Note that R
The AM 44 functions as a buffer memory for temporarily storing raster data.

The print head unit 60 includes the print head 2
8 and an ink cartridge can be mounted. The print head unit 60 is attached to and detached from the color printer 20 as one component. That is, when the print head 28 is to be replaced, the print head unit 60 is replaced.

FIG. 4 is an explanatory diagram showing the configuration of the head drive circuit 52. The head drive circuit 52 includes an original drive signal generation unit 521 and a drive signal shaping unit 522. The original drive signal generator 521 generates an original drive signal ODRV.
The drive signal shaping section 522 receives the input print signal PRT.
The drive signal DRV (i) for driving the piezo element PZT is generated by shaping the original drive signal ODRV according to (i). The head driving circuit 52 corresponds to a print head driving unit in the claims.

FIG. 5 is a timing chart showing the operation inside the head drive circuit 52. FIG. 5A shows the original drive signal ODRV generated by the original drive signal generation unit 521. As shown in the figure, the original drive signal ODRV includes four identical waveforms W0 in one pixel section.

FIGS. 5B to 5D show print signals PRT (i) for small dots, medium dots, and large dots. The print signal PRT (i) is a signal that becomes “H” or “L” for each waveform W0. The drive signal shaping unit 522 passes the original drive signal ODRV when the “H” print signal PRT (i) is input, and does not pass the original drive signal ODRV when the “L” drive signal is input. .
In this way, the drive signal DRV is generated by selectively passing any one of the waveforms W0.

FIGS. 5E to 5G show drive signals DRV (i) for small dots, medium dots, and large dots. Since the drive signal DRV (i) for small dots is “H” only for the second waveform W0 in the print signal PRT (i) for small dots, the original drive signal ODRV
Is a signal obtained by extracting only the second waveform W0 from the left. Similarly, the drive signal DRV (i) for the medium dot
Is a signal obtained by extracting the second and third waveforms W0 from the left of the original drive signal ODRV, and the drive signal DRV (i) for the large dot includes the entire waveform W0 from the original drive signal ODRV. Signal.

FIG. 6 is an explanatory diagram showing the relationship between the pixel value and the dot formation state. When the print image is a photograph, print data PD including 2-bit raster data having a pixel value of 0 to 3 is supplied to the control circuit 40 for each color of each pixel.
(FIG. 3). The CPU 41 of the control circuit 40
By processing this raster data, the print signal PR
T (i) is generated for each nozzle. Thus, the piezo element PZ according to each pixel value included in the raster data
A drive signal DRV (i) for driving T is generated. Specifically, when the pixel value is 0, the drive signal DRV
When (i) is not generated and the pixel value is 1 to 3, the drive signal DRV is used to form a dot of a size corresponding to this.
(I) is generated.

Specifically, as shown in FIG. 6A, when the pixel value is 0, no dot is formed. When the pixel value is 1, a small dot (second small section from the left) is formed by one ink droplet as shown in FIG. 6B. When the pixel value is 2, as shown in FIG. 6C, a medium dot (second and third small sections from the left) is formed by two ink droplets. When the pixel value is 3, as shown in FIG. 6D, a large dot (all small sections) is formed by four ink droplets.

On the other hand, when the print image is text, print data PD including 1-bit raster data having a pixel value of 0 or 1 is input to the control circuit 40 for each color of each pixel. In this case, when the pixel value is 0, the drive signal DRV (i) is not generated, and when the pixel value is 1, the drive signal DRV (i) is generated to form a large dot. As a result, when the pixel value is 0, no dot is formed as shown in FIG. When the pixel value is 1, a large dot (all small sections) is formed by four ink droplets as shown in FIG.

As described above, this printing apparatus expresses a gradation by changing the number of ink droplets ejected in one pixel area. Specifically, in the case of photo printing, the number of ink droplets formed in one pixel area is set to 0,
By selecting any one of 1, 2, and 4, it is possible to express four gradations.
By selecting the number of ink droplets to be formed in the pixel area from 0 or 4, it is possible to express two gradations. The smoothing process in the present embodiment is performed using such a gradation expression function. The details and method of the smoothing process will be described later in detail.

In the color printer 20 having the hardware configuration described above, the carriage 30 is reciprocated by the carriage motor 24 while the paper P is conveyed by the paper feed motor 22, and at the same time, the piezo elements of the print head 28 are driven. By discharging ink droplets of each color, ink dots are formed to form a multi-color and multi-tone image on the paper P.

B. First Embodiment FIG. 7 is a flowchart showing a procedure of a printing process according to an embodiment of the present invention.
In step S1, the user instructs the computer 90 to print. In step S2, when the user clicks a “property button” (not shown) in the print dialog box displayed on the CRT 21, the print mode selection unit 101 (FIG. 1) displays the property setting screen shown in FIG. To be displayed.

The user can specify various parameters defining the print mode in the property setting screen. The print mode basic setting screen of FIG. 8 includes the following elements to specify various parameters. (1) Image type selection menu IM: A pull-down menu for selecting one from a list of image types such as text and photos. (2) Print resolution setting switch SW: "clean" in FIG.
Switch to specify (high resolution) and "fast" (low resolution). (3) Paper type menu PM: A pull-down menu for selecting one from a list of papers such as plain paper and paper dedicated to an ink jet printer. (4) Ink color selection button CLR: a button for selecting whether to use color ink or only black ink.

Although the user can set other parameters on the detailed setting screen of the print mode, a description of these other parameters will be omitted below.

In step S3 of FIG. 7, when the user sets various parameters of the print mode and instructs the start of printing, in step S4, the smoothing process determination unit 102 (FIG. 1) switches to the set print mode. It is determined whether or not to perform the smoothing process accordingly.

FIG. 9 is an explanatory diagram showing a plurality of examples of the method of determining the smoothing process in step S4. In the first embodiment, as shown in FIG. 9A, the necessity of the smoothing process is determined based on only the image type among various parameters defining the print mode.

As shown in FIG. 9A, the image type includes a text and a photograph. In the first embodiment, the smoothing process determining unit 102 determines that the smoothing process is to be performed when the image type is text and that the smoothing process is not to be performed when the image type is photograph.

In step S5 in FIG. 7, the printer driver 96 generates print data according to the content of the smoothing processing decision in step S4. In particular,
The print data generation unit includes, in the print data, information as to whether or not to perform the smoothing process (smoothing process command information) and, when performing the smoothing process, information on the type of the smoothing process.

In the text print mode, the computer 9
From 0 to binary print data PD (1 bit for each color of each pixel) is sent to the printer 20. The printer 20
The printing is performed by performing a smoothing process on the binary print data (step S6). On the other hand, in the photograph mode, multi-valued (two bits for each color of each pixel) print data is sent from the computer 90 to the printer 20. Printer 20
Prints this multi-valued print data without performing the smoothing process (step S6). The details of the smoothing process will be described later.

As described above, in the present embodiment, the smoothing process is performed only when the image type selected by the user is text, so that if the smoothing process is performed, the image quality of the photograph, which is rather degraded, can be avoided. In addition, the outline of the printed image can be smoothed by the smoothing process in printing the text document.

C. Second Embodiment FIG. 9B is an explanatory diagram showing a smoothing processing determination method according to a second embodiment of the present invention. The difference from the smoothing processing determination method in the first embodiment is that the printing resolution is added to the parameter for determining whether or not the smoothing processing is required. The second embodiment is the same as the first embodiment except for a method for determining a smoothing process.

As shown in FIG. 9B, the printing resolution is
It is classified into high (clean) and low (fast). In this embodiment, the smoothing process determination unit 102 does not perform the smoothing process when the print resolution is high (fine),
If the printing resolution is low (fast), it is determined that the smoothing process is to be performed. The reason for this is that in the case of low resolution, serrated jaggies (jaggies) are conspicuous in oblique contours, but in the case of high resolution, jaggies are inconspicuous, so that smoothing processing is not required.

As described above, the determination as to whether or not to perform the smoothing process is not limited to a single parameter, but may be performed by a combination of two or more different printing parameters.

D. Third Embodiment FIG. 9C is an explanatory diagram showing a smoothing processing determination method according to a third embodiment of the present invention. The difference from the first and second embodiments is that one of the first smoothing process and the second smoothing process having different processing contents is selected according to the type of print medium. . The third embodiment is the same as the first and second embodiments except for this difference.

As shown in FIG. 9C, the print medium is divided into plain paper and paper other than plain paper (special paper or the like).
In this embodiment, the smoothing process determining unit 102 performs the first smoothing process when the print medium is plain paper, and performs the second smoothing process when the print medium is paper other than plain paper. decide. The reason for this is that the content of the smoothing process for smoothing the outline of the print image may differ depending on the print medium. The reason why the content of the smoothing process differs depending on the print medium will be described later.

As described above, when the contents of the preferable smoothing processing are different depending on the printing medium, it is preferable that one of a plurality of available smoothing processings can be selected.

As can be understood from the above description, when the specific print mode for printing the text is selected, the smoothing processing unit performs the smoothing process for smoothing the contours included in the print image, and processes the photograph. When the print mode for printing is selected, any method may be used as long as the smoothing process is not performed. Further, it is preferable that the smoothing processing section is capable of selecting the content of the smoothing process according to the printing medium when the preferable content of the smoothing process is different depending on the printing medium.

E. Example of Smoothing Process: FIG. 10 is an explanatory diagram showing the relationship between the pixel value of print data and the dot formation state in each pixel when the smoothing process is performed. FIG. 10A shows pixel values of raster data. In this example, black text printing is assumed, and the pixel value is a binary value of 0 or 1. FIG.
(B) and (c) show the dot formation state when two smoothing processes having different processing contents are performed. The hatched portion indicates a small section where the ink droplet is discharged.

If it is assumed that the smoothing process has not been performed, the following recording is performed on the print medium. When the pixel value is 0, no dot is formed on the pixel, and when the pixel value is 1, four ink droplets are ejected on the pixel. That is, when the pixel value is 0, recording is performed like the pixel in column a, row 1 in FIG. 10B, and when the pixel value is 1, recording is performed like the pixel in column a, row 3 in FIG. Becomes

When such recording without the smoothing process is performed, a saw-tooth jaggedness (jaggies) may occur. For example, in this example, there is a level difference in the recorded contents from column b to column c. Specifically, the pixel value of column b, row 2 is 0, but the pixel value of column c, row 2 on the right is 1, so that no dot is formed in the pixel of column b, row 2 On the other hand, four ink droplets are ejected to the next pixel in the c column and the second row, which is a step.
As described above, the number of ink drops between adjacent pixels sharply increases from 0 to 4. This rapid change is recognized by the human eye as a rapid change in the black part. This is what is called a jaggy. Smoothing processing in this embodiment is to smooth out this jaggy.

The contents of the smoothing process performed in FIG. 10B are as follows. A dot is not formed on the pixel in the b-th column and the second row where the pixel value is 0 when no smoothing process is performed. However, in the case where the smoothing process is performed, the pixel is indicated by the pixel on the b-th column and second row in FIG. One ink droplet is ejected to the right end of the pixel so that On the other hand, four pixels are ejected to the pixel in the c-th column and the second row having the pixel value of 1 when no smoothing process is performed.
In the case where the smoothing process is performed, two ink droplets are ejected to the central portion. As a result, in the case where the smoothing process is performed, the change in the number of ejected ink droplets is one from column b, row 2 to column c, row 2. This change is smaller than four changes that are obtained without the smoothing process.

In the case where the smoothing process is not performed, the number of ink droplets ejected in columns a to g and row 2 is 0, 0, 4, 4, 4, 0 and 0 in order from the column a. In this case, 0, 1, 2, 4, 2,
1, 0. Thus, it can be seen that jaggies are suppressed because the change in the amount of ink is gradual. Further, an ink droplet is ejected at the right end position in the pixel in the b-column and the second row, and an ink droplet is ejected at the left end position in the pixel in the f-column and the second row. Because of this, the change in the amount of ink is gradual, so in this processing example, a smoother contour is realized than when simply adjusting the amount of ink by appropriately selecting the ejection position of the ink droplet. Have been.

Note that, in the example shown in FIG.
The number of dots formed in a row is reduced by one in comparison with the case where the smoothing process is not performed. This is performed for the purpose of further reducing the level difference from column b to column c. A similar process is also performed for pixels in column e and row 3.

FIG. 10C shows another example of the smoothing process. The content of the optimum processing for smoothing the outline of the print image may vary depending on, for example, the characteristics of the print medium and the ink. In such a case, it is preferable to make available a plurality of smoothing processes according to the characteristics of the print medium and the ink, and to select the smoothing processes according to the print mode parameters as described above.

For example, it is assumed that the smoothing process shown in FIG. 10B is suitable for plain paper, and the smoothing process shown in FIG. 10C is suitable for special paper. In this case, in the third embodiment shown in FIG. 9C, the smoothing process shown in FIG. 10B is selected as the first smoothing process, and when the dedicated paper is selected, the second smoothing process is performed. The smoothing process shown in FIG. 10C is selected.

FIG. 11 is an explanatory diagram showing a method of the smoothing processing in this embodiment. In this processing example, the ejection position of the ink droplet is determined based on the pixel values of the recording target pixel and the pixel adjacent thereto. For example, FIG.
As shown in (a), the ink droplet ejection positions in column b and row 2 are:
It is determined based on the pixel value of the pixel in the b-th column and the second row and the pixel values of the eight pixels around the pixel. Similarly, FIG.
As shown in (b) and (c), the ink droplet ejection positions of the pixels in column c, row 2 and column d, row 2 are determined.

This smoothing process is performed for the print data PD.
CPU 4 includes a smoothing processing command
1 (FIG. 3). Specifically, the CPU 41
When recognizing that the print data PD includes a smoothing process command, the program reads a smoothing process program stored in the P-ROM 43 in advance and executes the smoothing process program to perform the smoothing process. Thus, the CPU 41 and the P-ROM 43 function as a smoothing processing unit in the claims.

FIG. 12 is an explanatory diagram showing the relationship between the pixel value of the recording target pixel and the ink droplet ejection position when performing the smoothing process. FIG. 12A shows an ink droplet ejection position when the pixel value is 0. FIG.
(B) shows the ink droplet ejection position when the pixel value is 1. Thus, a plurality of ink droplet ejection positions correspond to one pixel value. The ink droplet ejection position in each pixel is selected from the plurality of ink droplet ejection positions according to the pixel value of this pixel and the pixel values of the pixels surrounding this pixel.

The ink drop ejection position in the lower part of FIG. 12A and the ink drop ejection position in the upper part of FIG. 12B are the same. As described above, even if the pixel values at the positions where the ink droplets are ejected are different, the processing may be such that the same ink droplet ejection position is selected.

In the above-described smoothing process, the ink droplet ejection position of each pixel is determined based on the pixel value of each pixel and the pixel values of eight pixels adjacent to this pixel. May be determined in consideration of the pixel value of a pixel adjacent to the pixel. Alternatively, the determination may be made based on the pixel values of some of the eight adjacent pixels instead of all of them. Generally, in this embodiment, the smoothing process is
What is necessary is just to determine the ink droplet ejection position in accordance with the pixel value of each pixel and the pixel values of the neighboring pixels of this pixel.

In each of the above-described embodiments, ink droplets having different sizes can be formed by ejecting ink droplets to a plurality of different positions within one pixel area on the print medium. May be formed to form different dots. In general, the present invention can be easily applied to a printing apparatus capable of selectively forming any one of a plurality of types of dots having different sizes. However, if the ink droplets can be ejected to a plurality of different positions in a one-pixel area on a print medium to form dots having different sizes, the ink droplet ejection position can be selected in the one-pixel area.
The advantage is that the contour can be made smoother by making an appropriate choice.

F. Modifications: The present invention is not limited to the above-described examples and embodiments, and can be carried out in various modes without departing from the gist thereof. For example, the following modifications are also possible. is there.

In the above embodiments, black text printing is assumed. However, the present invention can be applied to the case of printing color text. Specifically, for example, in the property setting screen shown in FIG.
When the color ink is selected by R, the above-described smoothing process may be performed for each color ink.

The present invention can be applied to a drum printer. In the drum printer, the drum rotation direction is the main scanning direction, and the carriage traveling direction is the sub scanning direction. Also,
INDUSTRIAL APPLICABILITY The present invention can be applied not only to an ink jet printer but also to a dot recording apparatus that generally performs recording on the surface of a print medium using a recording head having a plurality of nozzle rows.

In the above embodiment, a part of the configuration realized by hardware may be replaced by software. Conversely, a part of the configuration realized by software may be replaced by hardware. Is also good. For example, some or all of the functions of the printer driver 96 shown in FIG. 1 may be executed by the control circuit 40 in the printer 20. In this case, some or all of the functions of the computer 90 as a print control device for creating print data may be performed by the printer 20.
Is realized by the control circuit 40 of FIG.

When part or all of the functions of the present invention are realized by software, the software (computer program) can be provided in a form stored in a computer-readable recording medium. In the present invention, "a computer-readable recording medium"
The term “not only includes portable storage media such as a flexible disk and a CD-ROM, but also includes internal storage devices in a computer such as various RAMs and ROMs and external storage devices fixed to the computer such as a hard disk. In.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a printing system as one embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a printer.

FIG. 3 is a block diagram showing a configuration of a control circuit 40 in the color printer 20.

FIG. 4 is an explanatory diagram showing a configuration of a head drive circuit 52.

FIG. 5 is a timing chart showing an operation inside the head drive circuit 52.

FIG. 6 is an explanatory diagram showing a relationship between pixel values and dots to be formed.

FIG. 7 is a flowchart showing a print data generation processing procedure in the embodiment of the present invention.

FIG. 8 is a view showing an example of a print mode basic setting screen displayed on the CRT 21;

FIG. 9 is an explanatory diagram showing a plurality of examples of a method for determining a smoothing process in step S4.

FIG. 10 is an explanatory diagram showing a relationship between a pixel value of print data and a dot formation state of each pixel when a smoothing process is performed.

FIG. 11 is an explanatory diagram showing a method of smoothing processing in the embodiment.

FIG. 12 is an explanatory diagram illustrating a relationship between a pixel value of a recording target pixel and an ink droplet ejection position when performing a smoothing process.

[Explanation of symbols]

 Reference Signs List 20 color printer 21 CRT 22 paper feed motor 24 carriage motor 26 platen 28 print head 30 carriage 32 operation panel 34 sliding shaft 36 drive belt 38 pulley 39 position sensor 40 control circuit 41 ... CPU 43 ... ROM 44 ... RAM 50 ... I / F Dedicated Circuit 52 ... Head Drive Circuit 54 ... Motor Drive Circuit 56 ... Connector 60 ... Print Head Unit 90 ... Computer 91 ... Video Driver 95 ... Application Program 96 ... Printer Driver 97 ... Resolution conversion module 98 ... Color conversion module 99 ... Halftone module 100 ... Rasterizer 101 ... Print mode selection unit 102 ... Smoothing processing determination unit 521 ... Original drive signal generation unit 522 ... Drive signal shaping unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H04N 1/405 H04N 1/40 B 5B021 1/409 101D 5C077 F term (Reference) 2C056 EA04 EC07 EC73 EC79 EC80 ED03 FA04 FA10 2C057 AF21 AG44 AM15 AM28 AN01 CA04 2C062 AA24 2C087 AA15 AA16 AB01 AB05 AC07 BA02 BA12 BB02 BD24 CB18 DA02 2C187 AC08 AE01 CC02 5B021 AA02 BB01 BB04 BB10 CC05 5C077 LL05 PN19 NN0508

Claims (10)

[Claims] 1. A printing apparatus that performs printing by ejecting ink droplets from a print head to form dots, wherein the user is provided with a specific text print mode suitable for printing a text document, and a photographic image. A print mode selection unit that allows selecting one of a plurality of print modes including a photo print mode suitable for printing, and when the specific text print mode is selected,
Perform a smoothing process to smooth the contours included in the print image, if the photo print mode is selected,
A printing apparatus comprising: a smoothing processing unit that does not perform the smoothing processing. 2. The printing apparatus according to claim 1, further comprising N types (N is an integer of 2 or more) of different sizes in one pixel area on the print medium using each nozzle. A print head drive unit capable of selectively forming any one of them, and a print data generation unit that generates print data representing a dot formation state in each pixel according to the selected print mode, When the specific text print mode is selected, the generation unit configures the print data by using binary pixel values indicating whether or not dots are formed in each pixel, while the photo mode is selected. In the case, the print data is configured by a multi-valued pixel value representing a dot formation state in each pixel, and the smoothing processing unit is configured to execute the processing when the specific text print mode is selected. Determining which one of the N types of dots is to be formed in each pixel according to the binary pixel value of each pixel and the binary pixel value of a neighboring pixel of each pixel. apparatus. 3. The printing apparatus according to claim 2, wherein the print head driving unit forms dots having different sizes by discharging ink droplets at a plurality of different positions within a one-pixel area on a print medium. It is possible, when the specific text print mode is selected, the smoothing processing unit determines the discharge position of the ink droplet in the area of each pixel, the binary pixel value of each pixel, and each pixel And a binary pixel value of a neighboring pixel of the printing apparatus. 4. The printing apparatus according to claim 3, wherein the parameters of the print mode selectable by the user include a type of a print medium, and the smoothing processing unit selects the specific text print mode. In this case, the ejection position of the ink droplet in the area of each pixel is determined according to the type of the selected print medium, the pixel value of each pixel, and the pixel value of a pixel adjacent to each pixel. Printing device. 5. The printing apparatus according to claim 1, wherein the parameters of the print mode selectable by the user include an ink color, and the smoothing processing unit selects a text print mode using color ink. A printing apparatus that performs the smoothing process for each color of ink when performed. 6. A printing control device that generates print data to be supplied to the printing unit in order to perform printing using a printing unit that performs printing by ejecting ink droplets from a print head to form dots. The user is allowed to select one of a plurality of print modes including a specific text print mode suitable for printing a text document and a photo print mode suitable for printing a photographic image. A print mode selection unit to perform, and when the specific text print mode is selected,
Generate print data including smoothing process command information for causing the printing unit to perform a smoothing process for smoothing an outline included in a print image, and when the photo print mode is selected, the smoothing process command information A print data generation unit that generates print data that does not include a print data. 7. A printing apparatus for performing printing by ejecting ink droplets from a print head and forming dots in accordance with given print data, wherein the print data is used to define an outline included in a print image. When smoothing processing command information indicating that smoothing processing for smoothing should be performed is included, the smoothing processing is performed.When the smoothing processing instruction information is not included, the smoothing processing without performing the smoothing processing is performed. A printing device comprising a unit. 8. A printing method for performing printing by ejecting ink droplets from a print head to form dots, comprising: providing a user with a specific text print mode suitable for printing a text document; Allowing the user to select one of a plurality of print modes, including a photo print mode suitable for printing the image, and an outline included in the print image when the specific text print mode is selected. Performing a smoothing process for smoothing the image, and not performing the smoothing process when the photo print mode is selected. 9. A computer program for controlling a printing apparatus including a printing unit that performs printing by ejecting ink droplets from a print head to form dots, and a computer, the computer program comprising: A function that allows selecting one of a plurality of print modes including a specific text print mode suitable for printing a text document and a photo print mode suitable for printing a photographic image; When the specific text print mode is selected,
Perform a smoothing process to smooth the contours included in the print image, if the photo print mode is selected,
A computer program for causing the computer to realize the function of not performing the smoothing process. 10. A computer-readable recording medium on which the computer program according to claim 9 is recorded.