JP2004155080A - Image recording apparatus, image recording method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the recording quality of character images in an image recording apparatus of an inkjet recording system or the like. <P>SOLUTION: At an image processing part 21, each of an edge region, an internal region, a line width and an inclination of character lines in an image to be recorded is detected. On the basis of the detected result, a central processing unit 20 controls dot formation at an image formation part 23 to densely form relatively large dots at the edge region of character lines of a small inclination and a large line width, to densely form relatively small dots at the edge region of character lines of a large inclination and a large line width, to form relatively large dots at the internal region of character lines of a large line width, to densely form relatively large dots at the edge region and the internal region of character lines of a small line width, and to strike overlapping relatively large dots and relatively small dots at the edge region and the internal region of character lines of an intermediate line width. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image recording apparatus for recording an image by forming dots on a recording material, and more particularly to an image recording apparatus capable of high-quality recording of characters.
[0002]
[Prior art]
Many image recording apparatuses, such as printers, copiers, and facsimile machines, which record images (characters, pictures, etc.) on a recording material such as paper based on image information, often record images using dots. 2. Description of the Related Art In recent years, an image recording apparatus of an ink jet recording method, which is excellent in terms of miniaturization, quietness, and high image quality of the apparatus, has been widely used.
[0003]
This ink jet recording type image recording apparatus can perform non-contact recording on a recording material by discharging ink droplets from an ink jet head which is a recording means, and uses an ink jet head using a multicolor ink to perform color printing. Conversion is also easy. In recent years, with the establishment of a technique for ejecting ink of minute droplets, a high-quality output with less graininess has been obtained for a halftone image such as a photograph.
[0004]
On the other hand, the possibility of forming fine droplets has caused a problem that the density is insufficient in a character image due to small dots formed.
[0005]
In connection with this problem, a method of reducing the dot density and increasing the dot diameter during character recording has been proposed (see Patent Document 1). However, when recording with a large dot diameter, there is another problem that a character image may be degraded due to jaggies.
[0006]
Regarding this jaggy, a method has been proposed in which dots in the edge region of the character line are made smaller and dots in the inner region of the character line are made larger (see Patent Document 2). However, there is a problem that a thin line of a character is liable to be deteriorated particularly due to a dot displacement.
[0007]
[Patent Document 1]
Japanese Patent No. 3219514
[Patent Document 2]
Japanese Patent No. 3029533
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide an image recording apparatus and an image recording method capable of recording a higher-quality character image in view of the above-mentioned problems.
[0009]
[Means for Solving the Problems]
According to an aspect of the present invention, there is provided an image recording apparatus for recording an image by forming dots on a recording material, as described in claim 1. An image recording apparatus including a detection unit including a unit that detects a line area and a line width, and a control unit that controls dot formation in a character line area according to the line width based on a detection result by the detection unit. is there.
[0010]
According to another feature of the present invention, as described in claim 2, in the image recording apparatus according to claim 1, the detecting means further includes means for detecting an edge area and an inclination of a character line area, respectively. The control means densely forms relatively large dots in an edge region of a character line having a small inclination and a large line width, and densely forms relatively small dots in an edge region of a character line having a large inclination and a large line width. Control to make it work.
[0011]
Another feature of the present invention is that, as described in claim 3, in the image recording apparatus according to claim 2, the detecting means further includes means for detecting an internal area of a character line area, The control means is to perform control to form relatively large dots densely in an inner region of a character line having a large line width.
[0012]
Another feature of the present invention is that, in the image recording apparatus according to the first, second, or third aspect, the control means is relatively large in a region of a character line having a small line width. It is to control to form dots densely.
[0013]
Another feature of the present invention is that, in the image recording apparatus according to any one of claims 1, 2, and 3, the control means is relatively large in a region of a character line having an intermediate line width. The object of the present invention is to perform control for overlapping a dot with a relatively small dot.
[0014]
According to another feature of the present invention, in an image recording apparatus for recording an image by forming dots on a recording material, an edge area of a character line in the image to be recorded is provided. Detecting means including means for detecting the internal area, the line width and the inclination, respectively, and control means for controlling dot formation in the edge area and the internal area of the character line based on the detection result by the detecting means, The control means controls to form relatively large dots densely in an edge region of a large line width with a small inclination, and to form relatively small dots densely in an edge region of a large line width with a large inclination. Control, control to form relatively large dots in the inner area of large line width character lines, control to form relatively large dots densely in the edge and inner regions of small line width character lines, middle An edge region and the interior region of the width of the character line is controlled to overstrike relatively big dots relatively small dots in an image recording apparatus for each.
[0015]
Another feature of the present invention is that, in an image recording method for recording an image by forming dots on a recording material, a region of a character line in the image to be recorded and An image recording method includes a detection step of detecting a line width, and a control step of controlling dot formation in a character line area according to the line width based on a detection result of the detection step.
[0016]
Another feature of the present invention is that, as described in claim 8, in the image recording method according to claim 7, the detecting step further detects an edge area and an inclination of a character line area, respectively, In the control step, control is performed such that relatively large dots are densely formed in the edge region of a large line width character line having a small inclination, and relatively small dots are densely formed in the edge region of a large line width character line having a large inclination. Is to do.
[0017]
Another feature of the present invention is that, in the image recording method according to claim 8, the detecting step further detects an internal area of a character line area, and the control step includes: Another object of the present invention is to perform control for densely forming relatively large dots in an inner region of a character line having a large line width.
[0018]
Another feature of the present invention is that, in the image recording method according to the seventh, eighth or ninth aspect, the control step is relatively large in a region of a character line having a small line width. It is to control to form dots densely.
[0019]
Another feature of the present invention is that, in the image recording method according to any one of claims 7, 8 and 9, the control step is relatively large in a region of a character line having an intermediate line width. The object of the present invention is to perform control for overlapping a dot with a relatively small dot.
[0020]
According to another aspect of the present invention, in an image recording method for recording an image by forming dots on a recording material, an edge area of a character line in the image to be recorded is provided. A detection step of detecting an internal area, a line width and an inclination, respectively, and a control step of controlling dot formation in an edge area and an internal area of a character line based on a detection result of the detection step, wherein the control step includes: Control to form relatively large dots densely in the edge region of a large line width with a small inclination, control to form relatively small dots densely in the edge region of a large line width with a large inclination, Control to form relatively large dots in the inner area of a character line with a line width, and control to form relatively large dots densely in the edge area and the inner area of a character line with a small line width. , An edge region and the interior region of the character lines of the intermediate line width is controlled to overstrike relatively big dots relatively small dots in an image recording method for each.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a block diagram showing an example of the overall configuration of an image recording apparatus according to the present invention. In FIG. 1, reference numeral 20 denotes a central processing unit (CPU) for controlling an image recording apparatus; 22, an image data input unit for inputting image data from an image pickup means such as an external scanner; An image processing unit for performing processing such as determination; 24, a ROM in which various programs executed by the central processing unit 20 are stored; 25, a RAM used as a work storage area of the central processing unit 20; Is an image forming unit that performs the following.
[0022]
From the image data input unit 22, RGB data obtained by converting analog data read by a CCD imager or the like into a digital value of 8 bits per pixel is input. The input image data is processed by the image processing unit 21. The contents of the processing and the configuration of the image processing unit 21 will be described below.
[0023]
FIG. 2 is a block diagram showing an example of the internal configuration of the image processing unit 21. In FIG. 2, reference numeral 100 denotes a data processing system for converting input image data into data for image formation. The image processing unit 21 also includes a detection system 101 for acquiring information necessary for the central processing unit 20 to control dot size and the like when forming a character image. In this embodiment, as described later, the detection system 101 is configured to detect a character line area (an edge area and an internal area), a line width, and a tilt.
[0024]
First, the data processing system 100 will be described. The data processing system 100 shown here is a general configuration of an ink jet recording apparatus. After performing scanner γ correction on input image data by a scanner γ correction unit 111, a filter processing unit 112 performs smoothing and edge enhancement. After that, the automatic background removal unit 113 removes the background of the document while maintaining the reproducibility of the low-density portions of the characters and patterns, and the color correction unit 114 converts the RGB data to the CMYK data. After performing UCR / UCA processing by UCR / UCA processing means, printer gamma correction is performed by printer gamma correction means 116, and finally, halftone processing such as dither processing and error diffusion processing is performed by halftone processing means 117. By performing the processing, the data quantized to the number of bits suitable for the image forming unit 23 (for example, about 1 to 2 bits per pixel) is obtained. To output. However, such a configuration of the data processing system 100 is merely an example, and it goes without saying that other configurations are possible.
[0025]
FIG. 3 is a block diagram illustrating a configuration example of the detection system 101. In FIG. 3, an edge area detection unit 200 is a means for detecting an edge area of a character line using the density characteristics of image data after scanner γ correction. If it is a region, "0" is output. The edge area detection unit 200 shown here includes binarization means 201 and 202, connected black pixel detection means 203, connected black pixel counting means 204, connected white pixel detection means 205, connected white pixel counting means 206, and logical product operation means 207.
[0026]
In such an edge area detection unit 200, the image data after the scanner γ correction is converted into black / non-black binary data by a binarizing unit 201 at a predetermined threshold. The connected black pixel detecting means 203 detects the connected black pixels using, for example, a 3 × 3 matrix pattern shown in FIG. 4 based on the binary data. In each pattern shown in FIG. 4, a black circle indicates a black pixel, and a cross indicates a black pixel or a non-black pixel. That is, each pattern in FIG. 4 detects a connected black pixel by utilizing the fact that black pixels are connected in any of the vertical, horizontal, and oblique directions in the black edge region. When the black pixel pattern conforms to any of the matrix patterns shown in FIG. 4, the central pixel of the matrix is detected as a connected black pixel connected to other surrounding black pixels.
[0027]
The image data after the scanner γ correction is converted into white / non-white binary data by a binarizing unit 202 at a predetermined threshold. Based on the binary data, the connected white pixel detection means 205 detects connected white pixels using, for example, a 3 × 3 matrix pattern shown in FIG. In each pattern shown in FIG. 5, a white circle indicates a white pixel, and a cross indicates a white pixel or a non-white pixel. When the white pixel pattern conforms to any of the matrix patterns shown in FIG. 5, the center pixel of the matrix is detected as a connected white pixel connected to other surrounding white pixels.
[0028]
The connected black pixel counting means 204 counts the number of connected black pixels in, for example, a 3 × 3 matrix centered on the target pixel, and determines that the target pixel is black active when the count value is equal to or more than a certain value. Activate the output. The connected white pixel counting means 206 similarly counts the number of connected white pixels in, for example, a 3 × 3 matrix centered on the target pixel, and determines that the target pixel is white active when the count value is equal to or more than a certain value. And activate the output. The AND operation unit 207 outputs the AND of the output of the connected black pixel counting unit 204 and the output of the white connected pixel counting unit 206. That is, the AND operation means 207 outputs “1” only when a black active pixel and a white active pixel are simultaneously present in a 3 × 3 matrix centered on the target pixel (the target pixel is a character line Is detected as an edge region of the image).
[0029]
The internal region detection unit 210 is a unit that detects an internal region of the character line region (a region surrounded by the edge region) based on the detection result of the edge region detection unit 200, and sets “1” for pixels in the internal region. , And outputs “0” to the other pixels. More specifically, the internal area detection unit 210 has a mask having the determination areas AR1 to AR4 in four directions in the vertical and horizontal directions around the target pixel as shown in FIG. To determine whether or not the target pixel is a region surrounded by the edge region, that is, an inner region of the character line. If it is determined that the target pixel is the inner region, “1” is set, and if not, “0” is set. Output. That is, when an edge region (edge pixel) exists in at least two of the four determination regions AR1 to AR4, the target pixel is determined to be an internal region of the character line. For example, when there is an edge region (edge pixel) in both AR1 and AR3, the pixel of interest is determined to be a line internal region of a character. Similarly, if there are edge pixels in three of the four directions AR1 to AR4 or in all directions, the pixel of interest is determined to be the internal region of the character line.
[0030]
As is clear from the description so far, in this embodiment, the character line area is detected separately from the edge area and the internal area. That is, a combination of the edge area detection unit 200 and the internal area detection unit 210 constitutes a character line area detection unit.
[0031]
The inclination detection unit 220 includes a filter processing unit 221 and a determination unit 222. The filter processing unit 222 applies, for example, each of the four filters shown in FIG. 7 to the image data after the scanner γ correction, using the pixel determined as the edge area by the edge area detection unit 200 as a target pixel. When the filter shown in FIG. 7A is applied, pixels forming a line in the sub-scanning direction are emphasized. When the filter shown in FIG. 7B is applied, pixels forming a line in the main scanning direction are emphasized. 7) or the filter of FIG. 7D is applied to emphasize pixels forming lines inclined 45 degrees counterclockwise or clockwise with respect to the main scanning direction. The determination unit 222 compares the values of the pixels determined to be the edge area after applying each filter, and when the pixel is most emphasized by the application of the filter in FIG. 7C or FIG. It is determined to be a pixel of a large character line.
[0032]
The line width detection unit 230 is a unit that detects the line width of a character line, and includes a contraction / expansion processing unit 231 and a determination unit 232. The erosion / expansion processing means 231 is provided for each pixel of the character line edge area detected by the edge area detection unit 200 and each pixel of the character line internal area detected by the internal area detection unit 210, that is, each pixel of the character line area Is used as a target pixel to perform contraction processing. The contraction process is a process of activating a target pixel when all pixels in a matrix of n × n pixels centered on the target pixel are edge region pixels or internal region pixels of a character line. Next, the contraction / expansion processing means 231 performs the expansion processing using each pixel activated in the contraction processing as a target pixel. The expansion process is a process of activating all the pixels in a matrix of m × m pixels centering on the target pixel. Such a set of the contraction processing and the expansion processing is repeated while changing the size of the matrix. The determination unit 232 determines the line width of the character line including the target pixel by comparing the processing results of each round.
[0033]
This line width detection will be described with reference to FIG. FIG. 8A is a diagram in which a pixel detected as an edge area or an internal area of a character line is represented by black, and other pixels are represented by white. FIG. 8B shows the result of performing a contraction process using a 3 × 3 matrix with each pixel shown in black as a target pixel. In FIG. 8B, active pixels are represented by black, and inactive pixels are represented by white. FIG. 8C shows the result of performing an expansion process using a 5 × 5 matrix with each of the active pixels as a target pixel. In FIG. 8C, active pixels are represented by black, and inactive pixels are represented by white. The active pixel in FIG. 8C can be determined as a pixel in a character line area having a line width equal to or larger than a predetermined size related to the size of the matrix used for the contraction / expansion processing. However, when the contraction processing using the 5 × 5 matrix is performed on each active pixel in FIG. 8A, no pixel becomes active. Therefore, there is no pixel that becomes active even if the expansion processing is performed thereafter. This means that the line width of the character line area including the pixel of interest is not the width determined by the current matrix size. By repeating the contraction processing and the expansion processing while changing the size of the matrix in this way, and comparing the results, the line width of the character line can be detected.
[0034]
As is apparent from the above description, the central processing unit 20 determines, based on the detection result of the detection system 101, the character line area (edge area and internal area) and its line width (small line width, large line width, intermediate width line). ) And the inclination can be recognized.
[0035]
Next, the image forming unit 23 will be described. Here, it is assumed that the image forming unit 23 is of an ink jet recording type. In the image forming unit 23, for example, as schematically shown in FIG. 9, four inkjet heads 300 for each color of C (cyan), M (magenta), Y (yellow), and BK (black) (in the figure) And ink cartridges 301 (only two colors are shown in the figure) for supplying ink of each color to them are mounted on the carriage 302. On the ink ejection surface of each ink jet head 300, for example, as shown in FIG. 10, a number of nozzles (ink ejection holes) 303 are formed, and ink droplets are ejected from the nozzles 303. During recording, ink droplets are ejected onto a recording material (such as recording paper) by each inkjet head 300 while moving the carriage 302 in the main scanning direction, and a character image or other image is formed on the recording material by dots of each color. Record. The size of the dot can be controlled in at least two or more steps. The sub-scan for printing is performed by moving the recording material. As a recording method, a so-called ink-on-demand method in which ink droplets are ejected only when necessary for recording is used. The ink-jet head 300 used in the ink-on-demand method includes a type using a piezoelectric element as a means for generating ejection energy (pressure), a type using a heating element, and a type using electrostatic force. It may be something.
[0036]
Although not shown, a recovery device having a general configuration for recovering a discharge failure of the inkjet head 300 is disposed at a position outside a recording area on one end side in the moving direction of the carriage 302. During printing standby, the carriage 302 is moved to the recovery device side, and the discharge surface of the inkjet head 300 is capped by the capping means of the recovery device to keep the nozzle 303 in a wet state, thereby preventing a discharge failure due to ink drying. In addition, even during printing, the carriage 302 is moved to the recovery device side as needed, and ink not related to printing is ejected from the inkjet head 300, so that the ink viscosities of all the nozzles 303 are constant and stable ejection performance is achieved. To maintain. In the case where a discharge failure occurs, the ejection surface of the ink head 300 is sealed by the capping unit of the recovery device, and bubbles and the like are sucked out of the nozzle 303 together with the ink by the suction unit of the recovery device, so that the ink adhering to the discharge surface is The ejection failure is recovered by removing dust, dust and the like by the cleaning means of the recovery device.
[0037]
Important characteristics when recording an image by the ink jet recording method are the ejection amount (Mj) of the ejected ink droplet and the flying speed (Vj) of the ink droplet. In particular, since the ejection amount (Mj) is the first factor that determines the dot size when the ink adheres to the recording material, it has a deep relationship with the resolution and image quality of the image. In the present invention, the dot size is controlled in two or more stages. On the other hand, the flying speed (Vj) is the value of the dot adhering to the recording material in the case where ink is continuously ejected to form a line drawing, or in the case where an image is formed by ejecting ink from a plurality of nozzles. In order to prevent the displacement, it is important that the flying speed is always stable.
[0038]
In the example of the image forming unit 23 shown here, image formation is performed by ejecting ink droplets from the above-described ink jet head 300, but in the present invention, the central processing unit 20 includes the detection system 101 (see FIG. The dot formation is controlled based on the information detected in 2). A control method of such dot formation and a drive control system of the inkjet head 300 will be described with reference to FIGS.
[0039]
FIG. 11 is a block diagram illustrating an example of an inkjet head drive control system in the image forming unit 23. In FIG. 11, reference numeral 457 denotes a driver IC for driving the ink-jet head 300, and includes a shift register 453, a latch circuit 454, a level conversion circuit 455, and an analog switch array 453. The analog switch array 456 includes analog switches AS1 to ASm that control the application of a drive voltage to individual electrodes corresponding to the nozzles on a one-to-one basis, as drive means for ejecting ink droplets from individual nozzles of the inkjet head 300. Become. 451 is a waveform generation circuit, and 452 is an amplifier.
[0040]
The central processing unit 20 supplies voltage data for generating the driving waveforms p1 to p3 to the waveform generating circuit 451, and supplies driving data Data, a shift clock, a latch signal, and the like to the driver IC 457.
[0041]
The waveform generation circuit 451 performs D / A conversion of the voltage data supplied from the central processing unit 20 by using an internal D / A converter, and as shown in (1) of FIG. , Three drive waveforms p1 to p3 having the same or different pulse widths are generated in time series. Drive voltages obtained by amplifying the drive waveforms p1 to p3 by the amplifier 452 are applied to the analog switches AS1 to ASm. The driving cycle is divided into four sections. In the preceding three sections, by turning on / off the analog switches AS1 to ASm as shown in (2) of FIG. 12, each individual electrode is turned on as shown in (3) of FIG. The application of the drive voltage to the recording medium is controlled, and as a result, as shown in FIG. 12D, the size of the dots formed on the recording material relatively changes in three stages of large, medium, and small. In the last divided period of the driving cycle, all the analog switches AS1 to ASm are turned off. In the last driving cycle shown in FIG. 12, since the analog switch remains off, no dot is formed.
[0042]
Data for controlling on / off of the analog switches AS1 to ASm in each divided section of the drive cycle is drive data Data, which is synchronized with the shift clock at the timing shown in FIG. Entered serially. After the drive data Data is sequentially stored in the shift register 453, it is latched by the latch circuit 454 by a latch signal. The signal corresponding to each analog switch latched by the latch circuit 454 is level-converted by the level conversion circuit 455 and applied to the analog switch as a control voltage.
[0043]
The central processing unit 20 generates drive data Data for recording any of large, medium, and small dots in an area where dots are to be recorded, but the character line area (edge) is detected by the detection system 101 (FIG. 2). (Area or internal area), the following dot size control is performed on the image forming unit 23. This control is performed according to a program stored in the ROM 24, and this program is also included in the present invention.
[0044]
The dot formation in the character line area is controlled differently depending on the line width.
[0045]
First, in a character line region having a large line width (for example, a width of 10 pixels or more), in a character line region having a small inclination, both the edge region and the internal region have relatively large dots (in this example, a large dot or a medium (Dots) are controlled to be densely formed. On the other hand, in a large line width character line area having a large inclination, relatively small dots (small dots in this example) are densely formed in the edge area, and relatively large dots (large dots or medium dots in this example) are formed in the internal area. (Dots) are densely formed. As described above, in the character line region having the large line width, relatively large dots are densely formed in the internal region regardless of the degree of the inclination, so that a high density can be obtained. In the character line region having a large inclination, relatively small dots are densely formed in the edge region, so that jaggy becomes less noticeable.
[0046]
For a character line area having an intermediate width (for example, a width of 4 to 9 pixels), in both the edge area and the inner area, a relatively large dot (a large dot or a medium dot in this example) and a relatively small dot (a small dot in this example) are used. (Dots). According to such dot formation control, a medium-width character line can be recorded at a sufficient density, and a middle-width character line region and a large-line character line region or a small-line character line region can be recorded. Image continuity is improved.
[0047]
For a character line area having a small line width (for example, 3 pixel width or less), both the edge area and the internal area are controlled so as to form relatively large dots (large dots or medium dots in this example). FIG. 14 shows how the thin and thick lines are recorded. As described above, since relatively large dots are densely formed in the character line area having a small line width, a sufficient density can be obtained, and even if the dot displacement occurs, the image is hardly deteriorated.
[0048]
It should be noted that even if relatively small dots partially coexist in a region where relatively large dots are recorded, and even if relatively large dots are partially coexistent in a region where relatively small dots are recorded, image quality is particularly high. No problem arises. Further, in the above-described example, dot formation control is performed with three types of character line widths. However, the density of large dots and small dots may be controlled for different line widths.
[0049]
Further, the image forming section 23 is not necessarily limited to the inkjet recording type, but may be an electrophotographic type as long as the recording dot size can be changed in several steps.
[0050]
Another embodiment of the present invention will be described with reference to FIG. In this embodiment, the application 513 on the host computer 510 issues a drawing request to the printer driver 514. The drawing request includes images such as graphics such as figures and lines, characters, and photographs. The printer driver 514 causes the raster image processor 511 to develop a bitmap image on the image memory 516 by the rasterizer 515 according to each drawing request. The image processing unit 518 performs various image processing on the bitmap image data in the image memory 516 and outputs the data to the color printer 512. At this time, the image processing unit 518 refers to the attribute map information in the attribute map memory 517 to perform image processing. Is switched as appropriate. Here, the attribute map information includes at least the position information of the character data and the character edge area information, and accordingly, the image processing unit 518 performs the same processing and the central processing as the image processing unit 21 similar to the above embodiment. The image forming unit 519 of the color printer 512 forms an image on a recording material by performing the same process for controlling dot formation in a character line area as the device 20. In this embodiment, when the output from the computer is printed out, information such as the position related to the character is clarified, so that there is no concern about occurrence of a character area detection error.
[0051]
As described above, the image forming apparatus according to the present invention is not necessarily limited to the mode in which all means related to the embodiment of the present invention are provided inside the apparatus. This also includes a mode in which the necessary means are provided. Needless to say, a form in which the raster image processor 511 and the image processing unit 518 are included in the printer 519 is also possible, and this is also included in the present invention.
[0052]
【The invention's effect】
As described above, according to the present invention, the dot formation in the character line area is controlled according to the line width, so that a character image can be recorded with good quality. That is, in a character line region having a large line width, a relatively large dot is densely formed in an internal region regardless of the degree of the inclination, so that a high density can be obtained. Since small dots are formed densely, jaggies become less noticeable, and therefore high-quality recording of large-width character lines is possible. In the character line area of the intermediate line width, both the edge area and the inner area overprint relatively large dots and relatively small dots, so that the character line of the intermediate line width can be recorded with sufficient density, The continuity of the image at the boundary between the middle line width character line and the large line width character line or the small line width character line is improved. In the character line area having a small line width, relatively large dots are formed densely in both the edge area and the internal area, so that sufficient density can be obtained. It is possible to obtain effects that are unlikely to occur.
[Brief description of the drawings]
FIG. 1 is a block diagram for describing an embodiment of the present invention.
FIG. 2 is a block diagram illustrating an example of a configuration of an image processing unit in FIG.
FIG. 3 is a block diagram illustrating an example of a configuration of a detection system in FIG. 2;
FIG. 4 is a diagram showing a matrix pattern for detecting connected black pixels.
FIG. 5 is a diagram showing a matrix pattern for detecting connected white pixels.
FIG. 6 is a diagram showing a mask for detecting an inner region of a character line region.
FIG. 7 is a diagram illustrating a filter for detecting the inclination of a character line area.
FIG. 8 is a diagram for explaining contraction processing and expansion processing for line width detection.
FIG. 9 is a perspective view illustrating an ink jet head and an ink cartridge mounted on a carriage.
FIG. 10 is a diagram illustrating an example of nozzle arrangement on an ink droplet ejection surface of an inkjet head.
FIG. 11 is a block diagram illustrating an example of a drive control system of the inkjet head.
FIG. 12 is a signal waveform diagram for explaining control of an output dot size of the inkjet head.
FIG. 13 is a timing chart showing a relationship between a driving cycle of the inkjet head and driving data input.
FIG. 14 is a diagram illustrating a recording state of a thin line and a thick line.
FIG. 15 is a block diagram for explaining another embodiment of the present invention.
[Explanation of symbols]
20 Central processing unit
21 Image processing unit
22 Image data input section
23 Image forming unit
100 Data processing system
101 Detection system
200 Edge area detector
210 Internal area detector
220 Tilt detector
230 Line width detector
451 Waveform generation circuit
452 amplifier
457 Driver IC

Claims (13)

In an image recording apparatus that records an image by forming dots on a recording material,
Detecting means including means for detecting each of a character line area and a line width in an image to be recorded; and
Control means for controlling dot formation in a character line area according to a line width based on a detection result by the detection means;
An image recording apparatus comprising: The image recording apparatus according to claim 1,
The detecting means further includes means for detecting an edge area and an inclination of the character line area, respectively.
The control means densely forms relatively large dots in an edge region of a large line width character line having a small inclination, and densely forms relatively small dots in an edge region of a large line width character line having a large inclination. An image recording apparatus for performing control. The image recording apparatus according to claim 2,
The detecting means further includes means for detecting an internal area of the character line area,
An image recording apparatus according to claim 1, wherein said control means performs control to form relatively large dots densely in an inner region of a character line having a large line width. The image recording apparatus according to claim 1, 2 or 3,
An image recording apparatus according to claim 1, wherein said control means controls to form relatively large dots densely in a character line area having a small line width. The image recording apparatus according to claim 1, 2 or 3,
An image recording apparatus according to claim 1, wherein said control means performs control for superimposing relatively large dots and relatively small dots in a character line area having an intermediate line width. In an image recording apparatus that records an image by forming dots on a recording material,
Detecting means including means for detecting an edge area, an internal area, a line width, and an inclination of a character line in an image to be recorded,
Control means for controlling dot formation in an edge area and an internal area of a character line based on a detection result by the detection means,
Has,
The control means controls to form relatively large dots densely in an edge area of a large line width with a small inclination, and forms relatively small dots densely in an edge area of a large line width with a large inclination. Control, control to form relatively large dots in the inner region of the character line with a large line width, control to form relatively large dots densely in the edge region and the inner region of the character line with a small line width, An image recording apparatus characterized in that control is performed so that relatively large dots and relatively small dots are overprinted in an edge area and an internal area of a character line. In an image recording method for recording an image by forming dots on a recording material,
A detection step of detecting each of a character line area and a line width in an image to be recorded;
A control step of controlling dot formation in a character line area according to a line width based on a detection result by the detection step;
An image recording method comprising: The image recording method according to claim 7,
The detecting step further detects an edge area and an inclination of the character line area, respectively.
In the control step, relatively large dots are densely formed in an edge region of a large line width of a character line having a small inclination, and relatively small dots are densely formed in an edge region of a character line of a large line width having a large inclination. An image recording method comprising performing control. The image recording method according to claim 8,
The detecting step further detects an inner region of the character line region,
The image recording method according to claim 1, wherein the control step performs control to form relatively large dots densely in an inner region of a character line having a large line width. The image recording method according to claim 7, 8 or 9,
The image recording method according to claim 1, wherein the control step includes controlling to form relatively large dots densely in a character line area having a small line width. The image recording method according to claim 7, 8 or 9,
The image recording method according to claim 1, wherein the control step performs control for superimposing relatively large dots and relatively small dots in a character line area having an intermediate line width. In an image recording method for recording an image by forming dots on a recording material,
A detection step of detecting each of an edge area, an internal area, a line width, and an inclination of a character line in an image to be recorded;
A control step of controlling dot formation in an edge area and an internal area of the character line based on a detection result by the detection step;
Has,
The control step includes controlling to form a relatively large dot densely in an edge region of a large line width with a small inclination, and forming a relatively small dot in an edge region of a character line with a large inclination with a large inclination. Control, control to form relatively large dots in the inner region of the character line with a large line width, control to form relatively large dots densely in the edge region and the inner region of the character line with a small line width, An image recording method, characterized in that control is performed to superimpose relatively large dots and relatively small dots in an edge area and an internal area of a character line. A program for executing the control step according to any one of claims 7 to 12.

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