JP2007118300A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device capable of improving image quality by forming the sharp edge part of an image such as high quality characters or the like without additional costs nor reduction in printing speed. <P>SOLUTION: When printing from left, the opposite ends or the right end of an image is formed only by a nozzle having inconspicuous satellite. When printing from right, a reverse procedure is carried out. More specifically, a means is used for forming an image only with nozzles ejecting no satellite in the image boundary portion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that forms an image by ejecting ink onto a recording medium such as black ink and color ink.

  2. Description of the Related Art Conventionally, inkjet recording methods and inkjet recording apparatuses that perform recording on various recording media have been widely applied as output means and the like of various apparatuses because they can perform high-density and high-speed recording operations.

  In general, an ink jet recording apparatus includes a carriage on which recording means (recording head) and an ink tank are mounted, a transport means for transporting a recording medium (recording paper), and a control means for controlling them. While the recording head for ejecting ink droplets is moved in the direction (main scanning direction) perpendicular to the transport direction (sub-scanning direction) of the recording medium, ink is ejected from the plurality of ejection ports to perform serial scanning. When recording is not performed, the recording medium is intermittently conveyed by an amount equal to the recording width.

  In addition, since this ink jet recording apparatus performs recording by ejecting ink onto a recording medium in accordance with a recording signal, it is known as an apparatus having low running cost and excellent quietness. In recent years, many products that use a plurality of colors of ink and can cope with color recording have been put into practical use.

  In a color ink jet recording apparatus that can cope with such color recording, black ink is frequently used for printing characters and the like, so that it is required to achieve sharpness, sharpness, and high recording density of printing. As one means, a technique is known in which the permeability of the black ink to the recording medium is lowered and the penetration of the coloring material contained in the black ink into the recording medium is known.

As another conventional example, Patent Document 1 can be cited.
JP 2000-318219 A

  However, even when such a low penetrability ink is used, printing sharpness may be impaired. One of the reasons is that a dot called a dot satellite, which is smaller than the main droplet of dots, adheres to the edge portion. FIG. 9 shows an image when a satellite appears. Although the edge portion of the image is sharply formed, satellites adhere to the side of the image, and the sharpness of the appearance is significantly impaired.

  Even when highly penetrating ink is used, for example, when a recording medium having a coating layer on the surface, such as ink-jet coated paper, is used, the edge portion of the image can be formed sharply. Even in this case, the satellite remarkably deteriorates the apparent sharpness.

  As one of countermeasures, there is means for suppressing the moving speed of the head. In general, since satellites have smaller dots than main droplets, the air resistance received by the dots is large, and a time difference occurs between the main droplets and satellite dots in the time from ejection to landing. Since the head performs recording while moving, the dots are ejected with speed not only in the ejection direction, that is, in the direction from the head to the paper surface, but also in the movement direction of the head. Then, dots are formed at different positions in the moving direction of the head by the time difference until landing on the main droplet and satellite paper. Further, by suppressing the moving speed of the head, it is possible to suppress the deviation between the main landing position and the landing position of the satellite.

  However, suppressing the moving speed of the head as described above means that the recording speed is suppressed. This makes high-speed printing impossible.

  As a second countermeasure, there is a method of reducing the distance between the head and the paper surface. In this method, if the distance between the head and the paper surface is shortened, the time to land on the paper surface is shortened for both satellites and main droplets, so that the moving distance in the head moving direction until the liquid droplets land is reduced. The distance between satellites and main drops is shortened.

  However, in order to stably reduce the distance between the head and the paper, extremely high accuracy is required mechanically. Therefore, there is a high possibility of cost increase such as using highly accurate parts, and a technically very difficult technique is required.

  As described above, in order to reduce satellites and obtain a sharp image, the prior art significantly increases the cost or delays the printing time.

  The present invention has been made in view of the above-described problems of the prior art, and is an inkjet recording apparatus that improves the image quality by forming the edge portion of an image sharply without increasing the cost and without reducing the printing speed. For the purpose of provision.

  In order to achieve the above object, the present invention has a recording head in which a plurality of nozzle groups for ejecting ink are arranged in a predetermined direction, and recording is performed using the recording head capable of recording at least one colored ink. The recording apparatus includes a means for detecting a part of the peripheral area of the image to be recorded or all of the peripheral area of the image, and the detected area includes a part of the nozzle group. An image is formed using only a specific part of the nozzles.

  The inkjet recording apparatus of the present invention has a recording head in which a plurality of nozzle groups for ejecting ink are arranged in a predetermined direction, and performs recording using the recording head capable of recording at least one colored ink. In the recording apparatus, the recording head completes printing by scanning at least one reciprocating scan at the same location, and the recording apparatus is a part of the peripheral area of the image to be recorded, or the image Means for detecting all of the peripheral area, and the detected area forms an image only in scanning in a specific direction.

  By taking a means for forming an image only with nozzles that do not emit satellites at the image boundary as described above, the edge portion of the image is sharply formed without cost and without lowering the printing speed. An ink jet recording apparatus that improves image quality is realized.

  Embodiments of the present invention will be described below.

  In the first embodiment of the present invention, a head having a head structure which is symmetrical with respect to the moving direction of the carriage as shown in FIG. FIG. 16 is a cross-sectional view taken along line EF in FIG. In FIG. 16, reference numerals 160 and 164 denote nozzles. When such a head is used, satellites and main droplets land in one of the heads very far apart in most heads. Therefore, satellites are very conspicuous. On the other hand, in the other row, satellites and main drops land very close to each other. As a result, the satellite becomes very difficult to see. FIG. 25A shows an example of an image when a 1-dot vertical ruled line is printed using this head. In this case, the head is moved from left to right on the paper surface. As shown in this figure, the nozzle on one side is easily affected by the satellite.

  FIG. 25B shows the state of vertical ruled lines when the same image is printed from right to left. As shown in this figure, satellites are now conspicuous for the image discharged from the nozzle on the opposite side.

  In this embodiment, paying attention to such characteristics of the head, when printing is performed from the left, both ends or the right end of the image are formed only by nozzles in which satellites are not conspicuous. Also, when printing is performed from the right, both ends or the left end of the image are formed by only the nozzle rows in which the satellite is not conspicuous, and a sharp image with an inconspicuous edge of the satellite is formed.

  In the second embodiment of the present invention, an image is formed by scanning the head at least twice, and the head does not have to have a line-symmetric structure as in the first embodiment. . In this case, when printing is performed from the left, the right end image is not printed, and the right end image is formed by printing from the right. On the other hand, in printing in which scanning from the right is performed, the left end image is not printed, and the left end image is completed only by scanning from the left. By adopting such a form, it is possible to form an image with sharp edges without causing satellites to protrude from both ends of the image.

The recording apparatus and recording method used in this example will be described below.
(Recording apparatus using ink set, recording method)
First, a recording apparatus according to the present invention will be described. In the present invention, it is preferable that a recording signal is given to the recording ink of the recording head and droplets are ejected by the generated thermal energy. The configuration of the recording head, which is the main part of the apparatus, is shown in FIGS.

  The head 13 is formed by bonding a glass, ceramic, plastic, or the like in which the ink flow path 14 is formed and a heat generating head 15 having a heat generating resistor used for thermal recording (the head is shown in the figure, but is not limited thereto). Obtained. The heat generating head 15 is a protective film 16 made of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heat generating resistor layer 18 made of nichrome or the like, a heat storage layer 19, and a substrate with good heat dissipation such as alumina. It is 20.

  The recording ink 21 reaches the discharge orifice 22 and forms a meniscus 23 by the pressure P.

  Here, when an electrical signal is applied to the electrodes 17-1 and 17-2, a region indicated by n of the heat generating head 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact therewith. The meniscus is ejected by the pressure, becomes a recording droplet 24 from the orifice 22, and flies toward the recording material 25.

  FIG. 3 is a schematic view of a recording head in which a large number of nozzles shown in FIG. 1 are arranged.

  1 is a cross-sectional view taken along line CD in FIG. 3B along the ink flow path, and FIG. 2 is a cross-sectional view taken along line AB in FIG. As shown in FIG. 3, in this embodiment, the nozzles are arranged in two rows, and both nozzles are offset by half of the nozzle interval on one side.

  FIG. 4 shows an example of an ink jet recording apparatus incorporating this head. Here, the blade 61 is a wiping member, and one end of the blade 61 is held by the blade holding member to become a fixed end, and forms a currant lever.

  The blade is arranged at a position adjacent to the recording area of the recording head, and has a configuration in which capping is performed by moving in a direction perpendicular to the moving direction of the recording head and abutting the ejection port surface.

  Further, reference numeral 63 denotes an ink absorber provided adjacent to the blade, and is held in a form protruding in the moving path of the recording head in the same manner as this blade. The blade 61, the cap 62, and the absorber 63 constitute an ejection recovery portion 64, and the blade 61 and the absorber 63 remove moisture, dust, and the like from the ink ejection port surface.

  Reference numeral 65 denotes a recording head which has discharge energy generating means and performs recording by discharging ink onto a recording material opposed to the discharge port surface on which the discharge ports are arranged. It is a carriage for performing. The carriage is slidably engaged with the guide shaft 67, and a part of the carriage is connected to a belt 69 (not shown) driven by a motor 68. As a result, the carriage can move along the guide shaft, and the recording area and its adjacent area can be moved by the recording head.

  On the other hand, 51 is a recording material supply unit for inserting a recording material, and 52 is a feed roller driven by a motor (not shown). With these configurations, the recording material is transported to a position facing the discharge port surface of the recording head, that is, a recording position, and is discharged to a discharge portion provided with a roller 53 as recording progresses.

  The image recording apparatus according to this aspect reciprocates the recording head in a direction orthogonal to the conveyance direction of the recording material, and from the head in both the forward scanning and the backward scanning. It is configured such that at least one of black ink and color ink can be applied to the recording material. Note that a conventionally known technique related to bidirectional printing can be used as a processing method for recording data in bidirectional printing.

  In the above configuration, when the recording head returns to the home position due to the end of recording or the like, the cap 62 of the head recovery unit 64 is retracted from the moving path of the recording head, but the blade protrudes into the moving path. As a result, the ejection port surface of the recording head is wiped. When capping is performed with the cap in contact with the ejection port surface of the recording head, the cap moves so as to protrude into the moving path of the recording head.

  When the recording head moves from the home position to the recording start position, the cap and the blade are at the same position as that at the time of wiping. As a result, even in this movement, the ejection port surface of the recording head is wiped.

  The movement of the recording head to the home position is not only at the end of recording or at the time of ejection recovery, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves the recording area for recording. Then, the wiping is performed with this movement.

  FIG. 5 shows an example of an ink cartridge containing ink supplied to the head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink container, for example, an ink bag, which contains ink for supply, and a rubber stopper 42 is provided at the tip thereof. By inserting a needle (not shown) into the stopper, the ink in the ink bag 40 can be supplied to the head. Reference numeral 44 denotes an absorber that receives waste ink.

  As the ink containing portion, an ink contact surface made of polyolefin, particularly polyethylene, is preferable. Further, as another aspect of the cartridge according to the present invention, there are provided two storage portions that individually store the black ink and the color ink, and a head for discharging the black ink and the color ink. An example of the cartridge is configured to be detachable and configured so that each ink can be supplied to the recording head.

  FIG. 7 shows an example of such a cartridge 1401, where 1403 is a black ink containing portion that contains black ink, and 1405 is a color ink containing portion that contains color ink. The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated, and a recording unit in which they are integrated as shown in FIG. 6 is also preferably used.

  In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage portion storing ink, for example, an ink absorber, is stored, and the ink in the ink absorber has a head portion 71 having a plurality of orifices. The ink is ejected as ink droplets. For example, polyurethane can be used as the material of the ink absorber.

  Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. This recording unit is used in the recording head shown in FIG. 4 and is detachable from the carriage 66.

  FIG. 8 is a block diagram of the electric control system showing a configuration example of the electric control system of the ink jet recording apparatus shown in FIG.

  In the figure, reference numeral 301 denotes a system controller that controls the entire apparatus, and a storage element (ROM) in which a control program is stored is arranged inside the microprocessor. Reference numeral 302 denotes a driver for driving the recording head in the main scanning direction. Reference numerals 304 and 305 denote motors corresponding to the drivers 302 and 303, respectively, and operate by receiving information such as speed and moving distance from the driver.

  A host computer 306 is an apparatus for transferring information to be recorded to the ink jet recording apparatus according to this embodiment. As a form thereof, in addition to a computer as an information processing apparatus, it is possible to adopt a form such as an image reader. A buffer 307 temporarily stores data from the host computer 306, and stores received data until data is read from the system controller 301. Reference numeral 308 (308k, 308c, 309m, 308y) denotes a frame memory for expanding data to be recorded into image data, and has a memory size of a sentence necessary for recording for each color. Here, a frame memory capable of recording one sheet of recording paper will be described, but it goes without saying that the present invention is not limited to the size of the frame memory. Reference numeral 309 (309k, 309c, 309m, 309y) is a storage element for temporarily storing data to be recorded, and the recording capacity changes according to the number of nozzles of the recording head.

  Reference numeral 310 denotes an appropriate control of the recording head according to a command from the system controller 301, and functions as a recording control unit (control means) for controlling the recording speed, the number of recording data, and the like. It functions as a processing means and a discrimination means for performing a discrimination operation. Reference numeral 311 denotes a driver for driving the recording heads 17k, 17c, 17m, and 17y for discharging ink, and is controlled by a signal from the recording control unit 310.

  In the control system having the above configuration, the image data supplied from the host computer 306 is transferred to the reception buffer 307, temporarily stored, and developed in the frame memory for each color. Next, the developed image data is read by the system controller 301 and developed in the buffer 309. The recording control unit 310 controls the operation of the recording heads 17k, 17c, 17m, and 17y based on the image data in each buffer.

  The present embodiment is characterized in that an image is formed at the edge of the peripheral image by the nozzle row on the side where the satellite is difficult to come out. In this embodiment, a printing method will be described in which an image is formed by moving the head in one direction on the paper surface, and the head moves only without printing in the reverse direction.

  Further, the present embodiment is characterized in that either of the left and right ends of the peripheral image is extracted and the data is changed so that the image is printed by the nozzle row on one side. First, an index pattern used in this embodiment will be described.

(Formation of input image by index pattern)
In a normal printer, the recordable output resolution and the data resolution transferred from a host computer or the like are often different. In printers such as those currently commercialized, it is becoming possible to land with an accuracy of more than or equal to a normal recording resolution of 1/120 inch (hereinafter referred to as 1200 dpi). This is because the information necessary for printing one sheet of A4 size paper is a very large amount exceeding 10 ^ 8 bits per color.

  Therefore, there is a method in which several pixels are used as one unit and only the number of dots arranged in the unit is formed as data. For example, the image is divided into 2 * 2 matrix units as shown in FIG. When information of “printing or not printing” is given to each of the four pixels, the host computer must transfer 4-bit information. On the other hand, it is assumed that only information such as “arrange any number of dots of 0, 1, 2, 3, 4” is transferred in this 2 × 2 matrix. With this method, it is sufficient to send 3-bit data such as 000 (0), 001 (1), 010 (2), 011 (3), 100 (4) to a 2 * 2 matrix. is there. As a result, the amount of data can be reduced to 3/4. Hereinafter, such an input data value is referred to as an “index value”.

  At this time, for example, in response to a command “place two dots in a 2 × 2 matrix”, the printer body determines two dots and places them in accordance with a rule. In this case, in consideration of high image quality and uniform use of nozzles, the dot arrangement method is usually changed sequentially in the image.

  FIG. 11 shows an example of image data when 3-bit data is distributed to a 2 * 2 matrix based on such information. In this manner, changing the arrangement of dots in the matrix with respect to images of the same data is referred to as “index rotation”. The dot arrangement in the matrix is called “index arrangement”, and the conversion of several bits of data into the index arrangement is called “index conversion”.

(Isolated point removal and peripheral image extraction)
Hereinafter, the image control of this embodiment will be described with reference to a flowchart and an image processing diagram.

  First, in this embodiment, the black image is separated into a peripheral area and an internal area. FIG. 12 is a flowchart illustrating a method for detecting pixels around black dots. FIG. 13 shows an image corresponding to the flowchart. In this embodiment, an example is shown in which the head performs printing while moving from left to right on the paper surface of FIG. In this case, since the satellite is slower than the main droplet, image deterioration due to the satellite tends to occur at the right end of the image. Therefore, only the rightmost region of the image is extracted.

  In this embodiment, the image formation output resolution is 1200 dpi and the input resolution is 600 dpi. That is, a 2 × 2 matrix is used for the index pattern. The number of input bits is 3 bits as described above. First, in step 121, the input data is binarized (FIG. 13 (a) to FIG. 13 (b)). At this time, if all the input pixels have an image of 2 dots or more with respect to the 2 × 2 image, it is determined that there is an image. This simplifies the removal of isolated points and the extraction of surrounding pixels. Here, the actual print data stores data that is not binarized.

  Next, in steps 122 to 126, isolated point removal is performed. This is for separating an edge image and a region where highlight dots are scattered. In step 122, a pixel of interest is selected from the binarized image. Subsequently, at step 123, the presence / absence of an image is determined for the eight pixels around the target pixel. Thus, when there are two or more image data in 8 pixels, it is regarded as not an isolated point, and the process proceeds to step 125 as it is. On the other hand, pixels having 1 data or less are converted to no data in step 4 by removing isolated points. The above steps are repeated for all pixels. Thereby, FIG. 13C is completed.

  Next, in steps 127 to 129, peripheral images are extracted. First, in step 127, inverted data is created for the original data from which isolated points have been removed (FIG. 13D). Subsequently, the black data is bolded in the left direction with respect to the black data of the image reversed in step 128 (FIG. 13E). Subsequently, in step 129, the logical product of the bold data and the original data is obtained (FIG. 13 (f)).

  Through the steps as described above, only the rightmost peripheral region can be extracted from the original data.

(Conversion of surrounding images)
Next, in step 1210, the image data of the peripheral area is converted. Here, the data is converted only in the portion regarded as the peripheral region in the 600 dpi 3 bit data of the original image. FIG. 14 shows a correspondence diagram. First, the data 000 is set to 000 because there is no image. Data 001 is converted to data 101 which is unused bits. For the data 101, index conversion is handled as shown in FIG. 14, and only fixed nozzles are used without performing index rotation as shown in FIG. The data from 010 to 100 is converted to 110 and two dots are arranged. In addition, the normal index expansion shown in FIG. 11 is performed except for the peripheral area.

  By such an operation, dots are thinned out in the peripheral area. However, there are few harmful effects on the image. This is because the number of dots is thinned out only at the periphery of the image area. In this embodiment, the isolated point is removed to achieve an ideal state. This is because a “island” having a small dot such as an image formed by several dots by isolated point removal is not extracted in the peripheral region. Therefore, for example, no harmful effect is generated in an image such as a stipple or a halftone image.

  FIGS. 15 and 24 show how the image changes by performing the conversion as shown in FIG. FIG. 24 is displayed in a data format, and FIG. 15 shows actual dots and satellites.

  FIG. 24A shows index values. FIG. 24B shows image data obtained by extracting only peripheral images after removing isolated points. This image is subjected to a process of thinning out the image used by the nozzle on the side where the satellite is generated. FIG. 24C shows the index value obtained by converting the index value of the peripheral image. On the other hand, FIG. 24 (d) is obtained by adding the conversion of FIG. 14, and the end portion is not printed by a nozzle that is likely to generate satellites. FIG. 24E is an index conversion of FIG. 24A as it is. In contrast, the dots are thinned out, but there is almost no problem because they are only at the ends.

  Next, the actual state of dots is shown in FIG. When printing is performed while moving the head from left to right using an image of input data as shown in FIG. 15A, a satellite is generated at the right end as shown in FIG. 15B when the image is formed. The reason why it does not occur at the left end is that the satellite flows to the right and lands, so that it does not stand out because it overlaps with the image in the center. At the right end, satellites are conspicuously generated only at specific nozzles. The head used in this example is shown on the right side of FIG. The head is seen from above and is a perspective view of the nozzle. Further, the head performs printing while moving to the right side in the figure. In this head, it has been confirmed by experiments that satellites are likely to be generated at the nozzle on the right side of the drawing. On the other hand, FIG. 15D shows an image when the image processing used in this embodiment is used. By avoiding the use of nozzle arrays on the side where satellites are generated, it is possible to form sharp images without satellites. Further, in FIG. 15D, the gap between the dots is formed at the edge so that the arrangement of the dots can be easily understood, but the actual image is often large enough to fill the space between the dots. There is almost no problem with thinning out.

  In this embodiment, the index conversion as shown in FIG. 14 is shown. However, as shown in FIG. 17, it is possible to prevent satellites from appearing only at the end dots, and the index pattern is limited to the above example. It goes without saying that it is not done.

(Relationship between nozzle array and satellite)
With respect to the head of the nozzle array arranged as shown in FIG. 15C, the head moves from the left to the right, so that the satellite overlaps the main droplet and becomes almost invisible in the right nozzle array of FIG. In the nozzles on the right nozzle row, the satellites are separated from the main droplets, and the image deterioration due to the satellites is noticeable. The present invention takes advantage of this feature to form high-quality images by using only the nozzles on the side of the satellite where the satellite is inconspicuous at the image boundary where the satellite is inconspicuous.

  The following describes the possible mechanism for such a phenomenon. FIG. 16 shows the head cut along line E_F in FIG. In the head of this embodiment, it has been confirmed that the head nozzle is ejected toward the center of the head due to the nozzle structure when the head is moved. This is probably because the liquid chamber is not symmetrical with respect to the left and right lines during foaming. Thereby, although the head moves from left to right, the main droplet 162 and satellite 161 discharged from the nozzle 160 on the traveling direction side fly in the lower left direction. Therefore, the relative speed in the lateral direction with respect to the paper surface 163 is canceled out, and as a result, the difference in the relative lateral movement distance between the main droplet 162 and the satellite 161 is reduced.

  On the other hand, with respect to the nozzle row 164 opposite to the head moving direction, both the main droplet 166 and the satellite 165 fly inside the nozzle row, so the relative speed of both droplets with respect to the paper surface increases and the landing deviation increases. End up.

  The present embodiment uses this phenomenon and is characterized in that an image is formed using only nozzles that do not easily generate satellites only in the edge region of an image where satellites are conspicuous.

  By adopting the configuration as described above, it is possible to form a sharp image without image deterioration due to satellites.

  In this embodiment, an example in which isolated point removal is performed is shown as a more preferable embodiment. However, since sufficient effect can be obtained even if it is not performed, isolated point removal is performed depending on the main unit and the image pattern as necessary. Just do it. This also applies to the following other embodiments.

  Furthermore, this embodiment is an example in which the nozzle structure as shown in FIG. 1 is used, and there is a possibility that the appearance of the satellite differs depending on the nozzle structure, the type of ink, and the like. Even in such a case, the same control as in this embodiment can be performed by changing the nozzle for printing the edge. In addition, a test pattern or the like may be printed as necessary, and image conversion may be performed after first determining the situation of the satellite by selection of a sensor or a user. The same applies to the other embodiments described below.

  In this embodiment, a method for performing reciprocal printing will be described. In this case, the extraction location of the peripheral area and the image data conversion method may be changed between the forward direction and the backward direction.

  FIG. 18 shows image extraction locations in the forward direction and the backward direction. In either direction, the image of the end region on the traveling direction side of the head 181 is converted. In other words, the image of the area shown with diagonal lines in the figure is converted.

  A method for converting input image data in a region to be converted next, when the head moves from the left to the right, as shown in FIG.

  Next, when the head moves from right to left, image formation as shown in FIG. 19 is performed. As a result, the left end region of the image uses the nozzle on the left side of the head, and an image having a sharp edge in the peripheral region of the image can be formed.

  FIG. 20 summarizes this image forming method in a flowchart.

  First, in step 201, it is confirmed from which side the head is going to print. Next, in step 202, the isolated points are removed from the image. Next, as in the first embodiment, the image area is inverted and the image data is bolded. At this time, when the head prints from the left, the peripheral portion of the right end is finally extracted by bolding the image leftward. Subsequently, the input index value is converted in the same manner as in the first embodiment for the peripheral area. Next, in steps 203 and 204, an index pattern is set according to the print direction so as to use a nozzle row in which satellites do not easily appear, and index expansion is performed. Subsequently, in step 205 and step 206, index expansion of the internal image area is performed. Finally, printing is performed in step 207.

  In this embodiment, satellite removal processing is performed on the boundary image only in the head traveling direction even in bidirectional printing. However, the same processing may be performed in the direction opposite to the head traveling direction so that the non-uniformity of the line drawing is not noticeable in the reciprocating printing.

  The present embodiment is characterized in that the image of the end area is directly thinned out without using the index pattern conversion.

  In this embodiment, normal index expansion without any processing is performed. Next, isolated point removal and peripheral image extraction are performed on the data. Subsequently, the dots that are likely to have satellites are thinned out directly in the edge image data.

  FIG. 21 illustrates the image forming method of this embodiment.

  FIG. 21A shows an index value, and FIG. 21B shows an image formed as it is without converting the surrounding area.

  FIG. 21C shows an image in which only the peripheral image is extracted after the isolated points are removed. In this embodiment, extraction is performed on the image after the index expansion. FIG. 21D is an image of a place other than that extracted. For the image of FIG. 21 (c), the logical product with the pattern as shown in FIG. 21 (e) is calculated so as not to perform printing with nozzles that are likely to generate satellites, thereby forming FIG. 21 (f). Finally, the logical sum of the thinned peripheral image FIG. 21 (f) and the image of FIG. 21 (d) is executed to realize FIG. 21 (g).

  FIG. 22 is a flowchart of the above data processing.

  First, in step 221, the image is indexed. Subsequently, isolated points are removed from step 222 to step 225. In the present embodiment, if there are only 4 pixels or less in the surrounding 15 pixels, they are regarded as isolated points. (This process may be performed as necessary as described above.) Next, a peripheral image is extracted from step 227 to step 229, and the difference between the peripheral image and the original image is internally stored in steps 2210 and 2211. Separate as a region. Subsequently, in step 2212, a thinning pattern of the peripheral area is formed in accordance with the printing direction from now on, and a logical product with the peripheral image is calculated in step 2213. Finally, the logical sum of the thinned peripheral image and the internal image is calculated to synthesize the image.

  By adopting the method as described above, it is possible to convert an image with relatively little calculation time without requiring index conversion processing.

  In this embodiment, a method for processing the input resolution at the same resolution as the output resolution will be described. That is, processing is performed at 1200 dpi for both the resolution of the input image and the resolution of the output image. That is, information received by the printer is a binary image of 1200 dpi.

  The data processing of the present embodiment employs the same method as that of the third embodiment. In the calculation flow of the image data shown in FIG. 22, it is possible to perform the following flow without performing the first calculation processing step 221.

  In the present embodiment, the present invention is applied to printing in two passes.

  Usually, as one method for printing an image with high image quality, there is a method called multi-pass printing. This completes the image by scanning the same portion a plurality of times. As a result, it is possible to alleviate factors such as nozzle deflection of the head and variations in the discharge amount. In this embodiment, in order to complete an image by dividing it into two times, printing is performed using a set of masks as shown in FIGS. 23 (e) and 23 (f). In the figure, a hatched portion represents a print area, and a non-hatched portion represents a non-print area. In this case, the logical product of the mask print area and the actual image area is calculated to determine the print area. In this embodiment, the printing is always regularly repeated from the left and the printing from the right.

  The present embodiment is characterized in that the peripheral area is printed only by nozzles that do not easily generate satellites, and the internal area is printed by a normal two-pass mask.

  The printing method of this embodiment will be described with reference to FIG. First, FIG. 23A shows a 600 dpi 3 bit image as an input image. FIG. 23 (b) shows the first index expanded. Similarly to the fourth embodiment, an input image having 1200 dpi 1 bit may be used.

  Next, FIG. 23C and FIG. 23D are data obtained as a result of extracting the peripheral region and the inside using the same method as in the third embodiment. FIG. 23C shows the peripheral area, and FIG. 23D shows the internal area. In this embodiment, isolated point removal is not performed.

  Next, FIG. 23E and FIG. 23F are two-pass masks for printing the internal region. When an image to be printed is scanned from left to right, the mask shown in FIG. 23E is used. When printing from right to left, the mask shown in FIG. 23F is used. The internal area of the image is printed with this mask. FIG. 23G and FIG. 23H are masks used when printing the peripheral area. Thus, the peripheral area is divided and printed. When an image to be printed is scanned from left to right, the mask shown in FIG. 23G is used. When printing from right to left, the mask shown in FIG. 23H is used.

  By using the method as described above, it is possible to form an image using a mask that uses nozzles uniformly in the inner area, and to form an image using only nozzles that do not easily generate satellites in the peripheral area of the image. .

  In this embodiment, an example applied to image formation of two or more passes is shown. In this embodiment, the left peripheral portion forms an image by printing from left to right. Then, the right peripheral part forms an image by printing from the right. According to such a printing method, although satellites are generated in the peripheral area of the image, satellites are formed toward the inner side of the image, so that it is possible to form sharp edges that are not conspicuous. In addition, since the internal image area is printed using a two-pass mask, it is possible to form a uniform image. FIG. 26 is a diagram for explaining a printing method in this embodiment. First, FIG. 26A shows an image in which index expansion is performed in the same manner as in the fifth embodiment. In this embodiment, the image is divided into a left peripheral image (FIG. 26B), an internal image (FIG. 26C), and a right peripheral image (FIG. 26D). In this embodiment, since the internal image is printed in two passes, FIG. 26 (e) and FIG. 26 (f), which are print masks for two passes, are prepared. Then, when printing from the left, the logical OR of the two products of the logical product of FIG. 26C, which is the entire peripheral image on the left side, the 2-pass mask FIG. 26E, and the internal image FIG. Print. This figure is FIG.26 (g).

  When printing is performed from the right, the logical product 2 of the image of FIG. 26D, which is the entire peripheral image on the right side, and the 2-pass mask FIG. 26F and the internal image (FIG. 26D). Print the logical sum of the users. (Fig. 26 (h))

FIG. 3 is a longitudinal sectional view of a recording head cut along an ink flow path. It is the sectional view on the AB line of FIG. FIG. 2 is an external perspective view illustrating a schematic configuration of a recording head in which a large number of nozzles illustrated in FIG. 1 are arranged in parallel. It is a perspective view which shows an example of the inkjet recording device incorporating the recording head. It is a vertical side view which shows an example of the ink cartridge which can be applied in this embodiment. It is a schematic plan view which shows the other example of the ink cartridge which can be applied to this embodiment. FIG. 7 is a schematic plan view showing a state where the cartridge shown in FIG. 6 is mounted on a recording head. It is a block diagram which shows the structure of the control system in this invention. It is the image of the prior art example which showed the influence with respect to the image of a satellite and a main droplet. It is a figure explaining the index process concerning the 1st embodiment of the present invention. It is a figure explaining the index process concerning the 1st embodiment of the present invention. It is a flowchart concerning the 1st example of the present invention. It is a figure explaining the image processing concerning 1st Example of this invention. It is a figure explaining the index processing method in the boundary image concerning the 1st example of the present invention. It is a figure explaining the image concerning the 1st example of the present invention. It is a figure explaining an example of the schematic sectional drawing of the head concerning this invention, and the mode of discharge of a main droplet and a satellite. It is a figure explaining the index processing method of the image concerning the 1st example of the present invention. It is the schematic explaining the image processing concerning 2nd Example of this invention. It is the schematic explaining the index processing method concerning the 2nd Example of this invention. It is a flowchart which shows the control action concerning the 2nd Example of this invention. It is the schematic explaining the image processing concerning 3rd Example of this invention. It is a flowchart which shows the control action concerning the 3rd Example of this invention. It is the schematic explaining the image processing concerning the 5th Example of this invention. It is the schematic explaining the image processing concerning 1st Example of this invention. It is a figure which shows a mode that 1 dot ruled line was printed using the head in this invention. It is the schematic explaining the image processing concerning the 6th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 13 Recording head 14 Ink flow path 15 Heat generating head 16 Protective film 17-1, 17-2 Aluminum electrode 18 Heating resistor 19 Heat storage layer 20 Substrate 24 Droplet 25 Recording medium 31 Nozzle 40 Ink bag 42 Plug 44 Ink absorber 45 Ink cartridge 51 Recording material 52 Paper feed roller 53 Paper discharge roller 61 Wiping member 62 Cap 62 'Same as above 63 Ink absorber 64 Discharge recovery part 65 Recording head 65' Same as above 66 Carriage 67 Guide shaft 68 Motor 69 Belt 70 Recording unit 71 Head part 72 Air communication port 17c, 17m, 17y, 17k Block diagram representing recording head 301 Block diagram representing system controller 302, 303 Block diagram representing motor driver 306 Block diagram representing host computer 307 Reception Block diagram representing a buffer 308c, 308m, 308y, 308k Block diagram representing a frame memory 309c, 309m, 309y, 309k Block diagram representing a frame memory 310 Block diagram representing a recording control unit 311 Block diagram representing a head driver 160, 164 Nozzle 161,165 Satellite 162,166 Main droplet 163 Recording medium 181 Head

Claims (17)

In an ink jet recording apparatus having a recording head in which a plurality of nozzle groups for ejecting ink are arranged in a predetermined direction and performing recording using the recording head capable of recording at least one or more colored inks.
The recording apparatus has a means for detecting a part of the peripheral area of the image to be recorded or all of the peripheral area of the image,
In the detected area, an image is formed by using only a specific part of the nozzle group, and an ink jet recording apparatus. The head is characterized in that printing is performed while moving in a direction perpendicular to the direction in which the nozzle groups are arranged,
The part of the peripheral area is a peripheral area on the traveling direction side and a peripheral area in a direction opposite to the traveling direction with respect to the moving direction of the head in the peripheral area of the image area to be printed. The ink jet recording apparatus according to claim 1. The head is characterized in that printing is performed while moving in a direction perpendicular to the direction in which the nozzle groups are arranged,
2. The inkjet according to claim 1, wherein the part of the peripheral region is a peripheral region on a traveling direction side with respect to a moving direction of the head in a peripheral region of an image region on which printing is performed. Recording device.   The head has two or more nozzle groups in parallel for at least one colored ink, and the partial nozzle group is a partial nozzle in the two or more nozzle groups. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is a nozzle group in a row.   5. The inkjet according to claim 1, wherein the nozzle group of the two or more rows has a nozzle structure that is substantially line-symmetric with respect to a moving direction of the head. Recording device.   The peripheral area detecting means counts the number of dots existing in an L × M (L, M = 1, 3, 5,... 2n + 1) matrix centered on the pixel of interest, and sets the dot on the pixel of interest. 6. The inkjet recording apparatus according to claim 1, wherein the pixel of interest is set as a candidate for a peripheral region when the count value exceeds a predetermined value. 6.   For the pixels in the candidate area in the peripheral area, the dot data of the candidate area is inverted, the inverted data is bolded in a predetermined direction, and the bolded data is re-inverted and the dot data of the candidate area 7. The ink jet recording method according to claim 1, wherein data obtained by logical product is used as peripheral area data.   8. The ink jet recording apparatus according to claim 7, wherein a direction of the bold data is a traveling direction with respect to a moving direction of the head and a direction opposite to the traveling direction.   8. The ink jet recording apparatus according to claim 7, wherein a direction of the bold data is a traveling direction with respect to a moving direction of the head.   The ink jet recording apparatus according to claim 1, wherein the energy for causing the ink to fly is thermal energy.   The ink jet recording apparatus according to claim 1, wherein energy for causing the ink to fly is mechanical energy.   The inkjet-resistant recording apparatus has means for printing a test pattern, and the specific part of the nozzles is selected by a user of the recording apparatus based on the test pattern. The ink jet recording apparatus according to claim 10.   The ink jet recording apparatus has means for printing a test pattern and means for automatically detecting the test pattern, and the specific part of the nozzles is selected based on the result of the automatic detection means based on the test pattern. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is provided. In an ink jet recording apparatus having a recording head in which a plurality of nozzle groups for ejecting ink are arranged in a predetermined direction and performing recording using the recording head capable of recording at least one or more colored inks.
The recording head has a recording method for completing printing by scanning at least the number of reciprocating scans at least once at the same location;
The recording apparatus has a means for detecting a part of the peripheral area of the image to be recorded or all of the peripheral area of the image,
In the detected area, an image is formed only in scanning in a specific direction. The head is characterized in that printing is performed while moving in a direction perpendicular to the direction in which the nozzle groups are arranged,
The part of the peripheral region is a peripheral region on the traveling direction side and / or a peripheral region in a direction opposite to the traveling direction with respect to the moving direction of the head in the peripheral region of the image region to be printed. The inkjet recording apparatus according to claim 14.   16. The inkjet recording method according to claim 14, wherein bubbles are generated in a recording liquid using thermal energy, and recording droplets are ejected based on the generation of the bubbles. Inkjet recording apparatus.   The ink jet recording apparatus according to claim 14, wherein the energy for causing the ink to fly is mechanical energy.

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