JP4101568B2 - Inkjet recording method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording method and apparatus for performing recording on a recording medium by discharging ink from a recording head, and more particularly to stabilization of an ink discharging state during printing.
[0002]
[Prior art]
As one of output devices such as computers and workstations, an ink jet recording apparatus is known as an ink jet type image forming apparatus that forms an image on a recording medium such as paper (recording paper) by ejecting ink. The ink jet recording apparatus usually includes a recording head on which nozzles for ejecting ink are formed, a carriage that carries the recording head and reciprocates in a predetermined direction, and a direction that crosses the predetermined direction (recording medium conveyance direction). And a recording medium conveyance device for conveying the recording medium.
[0003]
When forming an image on the paper, the paper being transported by the recording medium transport device is temporarily stopped, and the ink is ejected from the nozzles based on the image signal carrying the image information while reciprocating the carriage in the predetermined direction. And an image for one band is formed in a portion of the paper located in the image forming area facing the nozzle outlet (ink discharge port). Thereafter, the paper is transported by the width of one band and stopped, and ink is ejected from the nozzles based on the image signal while the carriage is reciprocated in the predetermined direction again. An image is formed in a portion located at. By repeating such an operation, an image is formed on the sheet.
[0004]
Ink jet recording devices perform recording by directly ejecting ink (recording liquid) from the recording head, so it is necessary to keep the ink in a state where it can be ejected at all times. Head cleaning, which is a difficult process, is necessary. There are the following means for cleaning the head.
[0005]
"Suction means"
When gas is mixed as bubbles in the supply path for supplying ink to the nozzles, which are ejection holes, or in the ink reservoir (common liquid chamber) near the nozzles, and the bubbles become a certain size, the supply of ink to the nozzles is hindered, Ink may not be ejected. As a countermeasure, means for sucking ink and bubbles up to the common liquid chamber by applying a negative pressure to the nozzle surface is adopted.
[0006]
"Wiper means"
Ink may not be ejected normally due to objects (paper dust, ink, etc.) that interfere with ink ejection that adheres to the surface (face surface) where the nozzles are placed. Means to wipe the surface are taken.
[0007]
"Preliminary discharge means"
Not all nozzles eject ink during image formation. Accordingly, the nozzles that are not ejected are dried by the ink, resulting in ejection failure or impossible. In order to improve image defects due to this, means for discharging all nozzles to a portion other than the recording medium every predetermined time to prevent drying is employed. Such ink ejection is called “preliminary ejection”.
[0008]
"Cap means"
During the non-printing time, the face of the nozzle is covered with a cap to prevent the nozzle from drying. In order to prevent drying, the cap contains an absorbent body soaked with suction ink to some extent.
[0009]
[Problems to be solved by the invention]
However, recent color ink jet recording apparatuses have reduced the amount of ink ejected at one time, and have achieved high resolution by ejecting a large amount of minute ink droplets. Accordingly, the ratio of the surface area of the nozzle to the volume of one ink droplet increases, and it is difficult to prevent the nozzle from drying because the time interval is too long in the preliminary discharge in a portion other than the recording medium in the conventional water-soluble ink. It has become to. As a result, there has arisen a problem that the ink density rises due to drying of the ink contained in the unused nozzle, and the uniformity of the ink density in the page is impaired. With the development of high-definition color, an apparatus using an ink with a low ink density (light color ink) has appeared, and this problem is likely to cause a remarkable change in ink density on the paper surface with such light color ink.
[0010]
Japanese Patent Application Laid-Open No. 55-139269, Japanese Utility Model Publication No. 3-45814, and Japanese Patent Application Laid-Open No. 6-40042 disclose techniques for performing preliminary discharge on a recording medium instead of a portion other than the recording medium. According to such a technique, it is considered that the effect of preventing ink drying can be obtained by increasing the frequency of preliminary ejection. This preliminary ejection onto the recording medium is referred to as “paper preliminary ejection” in this specification. However, these conventional techniques do not consider the problems in multi-pass printing. That is, in multi-pass printing, the pass in which image data (including preliminary ejection data) is printed is determined by the multi-pass mask data. Therefore, depending on the mask data, there is a possibility that the preliminary ejection on the paper is performed concentrated on a specific pass. In this case, nozzles that are not involved in the preliminary ejection may occur.
[0011]
The present invention has been made in such a background, and an object of the present invention is to prevent a change in ink density due to ink drying in the nozzles by proper preliminary paper ejection even when multi-pass printing is adopted. It is an object of the present invention to provide an ink jet recording method and apparatus.
[0012]
[Means for Solving the Problems]
  The ink jet recording method according to the present invention comprises:Ink jet recording head having a plurality of nozzles for recording dots of a predetermined colorThe recording medium transport directionIntersect withScan in directionLet the recording mediumMultipathRecordAn inkjet recording method for performingSaidMultipathRecordA step of preparing mask pattern data corresponding to the number of passes,Represents the image to be recordedPredetermined for image dataRecordAccording to the position patternDot dataA step of addingThe added dot dataAre distributed in different pathsRecordChanging the mask pattern data to:Dot dataAnd the multi-pass based on the changed image data and the changed mask pattern data.RecordSteps to do andHave,The dot data is added and the mask pattern data is changed so that all of the plurality of nozzles record at least one dot in all passes of the multi-pass recording.It is characterized by that.
[0013]
  According to another aspect, the ink jet recording method according to the present invention includes a transport operation for transporting a recording medium by an amount smaller than the width of an ink jet recording head having a plurality of nozzles for ejecting ink of a predetermined color. An inkjet recording method for performing multi-pass recording in which recording on a unit area of the recording medium is completed by a plurality of scans of the inkjet recording head, wherein all of the plurality of nozzles are in each pass of the multi-pass recording. Adding preliminary ejection data for preliminary ejection of the predetermined color ink to the recording medium at least once to image data representing an image to be recorded, and in each pass of the multi-pass recording All of the plurality of nozzles reserve the ink of the predetermined color for the recording medium at least once. A step of preparing mask pattern data for multi-pass printing that does not mask the preliminary discharge data so that the preliminary discharge data is masked, and the image data to which the preliminary discharge data is added and the multi-pattern based on the prepared mask pattern. And a step of performing pass recording.
[0014]
  An ink jet recording apparatus according to the present invention performs multi-pass recording on a recording medium by causing an ink jet recording head having a plurality of nozzles for recording dots of a predetermined color to scan in a direction intersecting the conveyance direction of the recording medium. A recording apparatus comprising: a memory for storing mask pattern data for each pass for multi-pass recording; and image data representing an image to be recorded on a recording medium according to a predetermined recording position pattern Adding means for adding dot data to be recorded on the recording medium, and changing mask pattern data read from the memory so that the dot data added by the adding means is distributed and recorded in different paths. A change unit, image data to which dot data is added by the addition unit, and the change Control means for performing control so as to perform the multi-pass printing based on the mask pattern changed by the stage, and the adding means and the changing means include the plurality of nozzles in each pass of the multi-pass printing. The dot data is added and the mask pattern data is changed so that at least one dot is recorded in all.
[0015]
  According to another aspect, the ink jet recording apparatus according to the present invention includes a transport operation for transporting a recording medium by an amount smaller than the width of an ink jet recording head having a plurality of nozzles for ejecting ink of a predetermined color. An inkjet recording apparatus that performs multi-pass recording in which recording on a unit area of the recording medium is completed by a plurality of scans of the inkjet recording head, wherein all of the plurality of nozzles are in each pass of the multi-pass recording. Adding means for adding preliminary ejection data for preliminary ejection of the ink of the predetermined color to the recording medium at least once to image data representing an image to be recorded; In each pass, all of the plurality of nozzles apply at least one ink of the predetermined color to the recording medium. A memory storing mask pattern data for multi-pass printing that does not mask the preliminary discharge data so that preliminary discharge can be performed, image data to which preliminary discharge data is added by the adding means, and a mask stored in the memory And a control means for controlling to perform the multi-pass recording based on the pattern.
[0016]
  In the ink jet recording apparatus, the ink jet recording head further includes a plurality of nozzles for ejecting ink of a color different from the predetermined color ink, and the ink of the different color is not preliminarily ejected to the recording medium. Can be.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 is a perspective view showing a schematic configuration of a main part of a plotter which is an example of an ink jet recording apparatus according to the present invention.
[0020]
The plotter 10 includes a platen 14 on which a sheet 12 conveyed in the direction of arrow A is placed. Two scanning rails (guide rails) 16 are spanned above the platen 14 in parallel to the platen 14. A carriage 20 that reciprocates in the directions of arrows B and C (direction orthogonal to the direction of arrow A) by a motor (not shown) and a belt 18 is attached to the scanning rail 16 via a slide bearing (not shown). Yes.
[0021]
On the carriage 20, four recording heads 22K (black), 22C (cyan), 22M (magenta), and 22Y (yellow) having ink discharge ports (nozzle outlets: not shown) for discharging ink are mounted. Yes. However, the number of recording heads is not limited to four. For example, a recording head such as light cyan or light magenta may be further provided. In front of the ink ejection opening is an image forming area 23 where an image is formed. Ink is ejected from the ink ejection port to a portion of the paper 12 that is located in the image forming area 23, whereby an image is formed in this portion.
[0022]
In a corner of the movable range of the carriage 20 away from the image forming area 23, ink is forcibly sucked from the nozzles, and the ink supply path and nozzles formed in the recording head 22 are cleaned. A recovery device 30 is provided for changing the ink discharge state of the recording head 22 to the initial discharge state.
[0023]
In forming an image on a sheet 12 such as a roll sheet, the conveyance roller is placed on the platen 14 and a part of the outer peripheral surface is exposed from an opening (not shown) formed in the platen 14. The sheet 12 is conveyed by rotating the conveyance roller 24 by a conveyance motor (not shown) while the sheet 12 is sandwiched between the sheet 24 and the pinch roller 26 that presses both ends of the sheet 12 from above. The carriage 20 is reciprocated in the directions of arrows B and C above the paper 12 to generate image signals carrying image information transmitted from the head driving system 236 (see FIG. 2) to the recording heads 22K, 22C, 22M, and 22Y. Based on this, ink is ejected from the nozzles, and an image is formed on a portion of the paper 12 located in the image forming area 23.
[0024]
During the printing (image forming) operation, when it becomes necessary to suck ink from the nozzles in order to clean the nozzles, the carriage 20 is moved above the recovery device 30. When the image formation is completed, a cutter (not shown) mounted on the carriage 20 is ejected to a predetermined position, and the paper 12 is cut into a predetermined size.
[0025]
The recovery device 30 includes four rubber caps 32K, 32C, 32M, and 32Y that detachably cover the outlets of the nozzles of the four recording heads 22K, 22C, 22M, and 22Y. One end of a tube (not shown) is connected to each cap 32K, 32C, 32M, 32Y, and the other end of the tube is connected to a suction pump (not shown). The four caps 32K, 32C, 32M, and 32Y are fixed to the cap base 32. The cap table 32 can be driven up and down by a recovery drive system (235 in FIG. 2). When the head is not used, the cap table 32 is driven upward to cap the nozzle portion. The cap base 32 is fixed in a state where it is raised upward in order to perform a cap when the head is not used and when suction is performed. During printing (except during suction), the cap base 32 is driven downward and fixed in a state of being lowered downward so as not to hinder the movement of the carriage.
[0026]
FIG. 2 shows a schematic configuration of control hardware of the plotter 10.
[0027]
The plotter 10 includes an image controller 210 and a print engine 230. The plotter 10 receives image data from a host computer (external device) (hereinafter also simply referred to as a host) 100 and performs recording processing.
[0028]
The image controller 210 notifies the print engine 230 of a control command in accordance with a processing command from the operation unit (not shown) of the plotter 10 or the host computer 100. In addition, during printing, the recording data received from the host 100 is analyzed and developed to convert each color into binary image data. The operation unit includes an input unit including various input keys on an operation panel provided in the plotter 10 and a display unit including a liquid crystal display. The print engine 230 performs an actual printing operation based on the control command and image data sent from the image controller 210.
[0029]
The image controller 210 and the print engine 230 are connected by a dedicated interface. The image controller 210 sends a command for notifying the print engine 230 of a control command, and the print engine 230 notifies the image controller 210 of a change in the state of the image controller 210. Communication including status transmission and image data transfer from the image controller 210 to the print engine 230 can be performed.
[0030]
The print engine 230 itself is controlled by an MPU (Micro Processor Unit) 231 in accordance with a program recorded in the ROM 237. The RAM 238 is used as a work area or temporary data storage area for the MPU 231. The MPU 231 controls the carriage drive system 233, the transport drive system 234, the head recovery drive system 235, and the head drive system 236 via the ASIC 232. Further, the MPU 231 is configured to be able to read / write from / to the print buffer 239 and the mask buffer 240 readable / writable from the ASIC 232.
[0031]
The print buffer 239 temporarily stores image data (hereinafter also referred to as nozzle data) converted into a format that can be transferred to the head. The mask buffer 240 temporarily holds a predetermined mask pattern for performing AND processing (masking with logical product) on the data transferred from the print buffer 239 when transferring to the head. By thinning the mask pattern and the nozzle data, thinning for multi-pass printing is realized. A plurality of sets of mask patterns for multi-pass printing with different numbers of passes are prepared in the ROM 237, and the corresponding mask patterns are read from the ROM 237 and stored in the mask buffer 240 during actual printing.
[0032]
Next, an outline of the operation of the plotter 10 during printing will be described with reference to the block diagram of FIG.
[0033]
Printing processing is started when image data is sent from the host 100 to the plotter 10. The image controller 210 analyzes the image data received from the host, generates information necessary for printing such as print quality and margin information, and further analyzes and expands the image data to start converting each color to binary image data. To do. At this time, information necessary for printing by the print engine 230, such as print quality and margin information, is notified to the print engine 230. In the print engine 230, the notified information is processed by a microprocessor unit (MPU) 231 via an application specific integrated circuit (ASIC) 232 and held in the RAM 238. This information is then referred to in the required situation and used to isolate the process. Further, the mask pattern is written into the mask buffer 240. The mask pattern to be written at this time is a pattern that does not mask the dots that are ejected in each pass of preliminary ejection on the paper described later. Specific examples thereof will be described later.
[0034]
When the notification of necessary information is completed, the image controller 210 starts transferring the binary image data of each color converted from the image data to the print engine 230. The print engine 230 converts the transferred image data into nozzle data and writes it into the print buffer 239. Rewrite nozzle data by calculation with respect to the written nozzle data (as shown in FIG. 5, the ejection dots of the paper preliminary ejection pattern are regular and can be rewritten by calculation), or a predetermined paper surface The ejection dots in the preliminary ejection on the paper surface are added by OR (logical sum) with the preliminary ejection pattern (ejection position pattern).
[0035]
By repeating the image transfer from the image controller 210, the print engine 230 sequentially holds the transfer data to the head in the print buffer 239. When the data held in the print buffer 239 has accumulated to the extent that actual band data can be printed, the MPU 231 transports the paper by the transport drive system 234 via the ASIC 232, and the carriage drive system 233 carries the carriage. Move. Further, the recovery system is driven by the recovery drive system 235 to perform a necessary recovery operation before printing. Further, the image output position and the like are set in the ASIC 232, the carriage is driven, and printing is started.
[0036]
When the carriage moves and reaches the print start position set in the ASIC 232, the nozzle data on which the paper preliminary ejection pattern (predetermined ejection position pattern) described above is ORed in accordance with the ejection timing is sequentially read from the print buffer 239. . At the same time, the corresponding mask pattern is read from the mask buffer 240. The read nozzle data and mask data are ANDed (logical product processing) and transferred to the head. Under the control of the head driving system 236, the head performs ejection by driving the nozzles according to the transferred data. The printing process is realized by repeating the processes from the reception of the image from the image controller 210 to this step.
[0037]
Hereinafter, various patterns and operations for preliminary ejection on the paper surface in the present embodiment will be described in detail.
[0038]
The relationship between the mask pattern 300 and the image data in the 4-pass printing will be described with reference to FIG. As the mask pattern 300, mask data 301 to 304 are prepared corresponding to each divided nozzle region 221 divided according to the number of multi-passes, in other words, corresponding to each pass. For example, if there are four passes, the nozzle array of the head is divided into four divided nozzle regions 221 and four mask data 301 to 304 (masks 1 to 4) are associated with each. When these four mask data 301 to 304 are ORed (logical sum processing) in units of pixels at the same position, the mask of each pass is set so that all the dots in the unit area (for one pass) become logic “1”. A pattern is constructed. The configuration shown in FIG. 3 is merely an example, and the configuration of the mask pattern may be other than that illustrated.
[0039]
In the example shown in the figure, the sheet is conveyed by one pass from the lower side of the figure to the nozzle row of the head. Each of the masks 1 to 4 is ANDed with the image data while being transported from the first pass to the fourth pass, and ink dots are output. An output with ANDed pattern and image is obtained. (In the figure, “|” is an operator that indicates an OR (logical sum), and “&” is an operator that indicates an AND (logical product)). Therefore, the dot output result after the fourth pass printing is the image data itself, and the image is completed. (Refer to the area of the first pass of the fourth pass in FIG. 3)
[0040]
FIG. 4 and FIG. 5 show examples of the mask pattern and the paper preliminary ejection pattern in the case of 4 passes, where the nozzle length used is 16 dots. Here, in order to simplify the description, the nozzle length, the paper preliminary ejection pattern size, and the mask pattern size are made smaller than the actual size.
[0041]
A mask pattern 300 shown in FIG. 4 is obtained by changing a normal mask pattern for preliminary ejection on the paper surface in this embodiment. In the figure, the smallest grid of the grid corresponds to one dot. The blank dots are written with normal 4-pass mask data. The changed part is a dot indicated by black and hatched in the figure. Black dots are fixed at 1 (discharge) and hatched dots are fixed at 0 (non-discharge).
[0042]
FIG. 5 shows a paper preliminary ejection pattern 400 corresponding to the mask pattern 300 of FIG. This pattern shows an ejection dot pattern that is actually ejected onto the paper as preliminary ejection on the paper. The paper surface preliminary ejection pattern is composed of several dots of multi-pass for each nozzle. In the example of FIG. 5, since there are four passes, ejection dots are set for each nozzle by four passes. Since this paper preliminary discharge is performed together with the printing of the actual image, the paper preliminary discharge pattern 400 of FIG. 5 is printed together with the image. The dots 401, 402, 403, and 404 in FIG. 5 correspond to the dots 311, 312, 313, and 314 of the mask pattern 300 in FIG. 4 and are printed by different nozzles in different passes. Also, the dots 401, 411, 421, and 431 in FIG. 5 correspond to the dots 311, 321, 331, and 341 in FIG. 4 and are all printed in the same pass (first pass). The dots 402, 412, 422, and 432 in FIG. 5 correspond to the dots 312, 322, 332, and 342 in FIG. 4 and are printed in the second pass. The dots 403, 413, 423, and 433 in FIG. 5 correspond to the dots 313, 323, 333, and 343 in FIG. 4 and are printed in the third pass. Similarly, the dots 404, 414, 424, and 434 in FIG. 5 correspond to the dots 314, 324, 334, and 344 in FIG. 4 and are printed in the fourth pass.
[0043]
The meaning of the arrangement of the pre-discharge mask portion of the mask pattern 300 (black and hatched) and the ejection dots (black) of the paper surface preliminary discharge pattern 400 are as follows.
(1) The predetermined ejection position pattern of the paper surface preliminary ejection pattern 400 has ejection dots for at least the number of passes on each line along the main scanning direction of the carriage. These adjacent ejection dots are separated by a predetermined distance.
(2) The mask pattern 300 is determined so as to distribute at least the number of ejection dots on each line along the main scanning direction of the carriage to each pass.
Thus, each nozzle ejects ink at least once in each pass. (In actuality, the sheet is ejected a plurality of times at a repetition cycle of the preliminary ejection pattern 400.)
(3) Nozzles belonging to different nozzle areas (different passes) eject ink at different main scanning direction positions from corresponding nozzles belonging to other nozzle areas. For example, in the example of FIG. 4, the uppermost nozzle of the nozzle area to which the mask data 301 is applied, the uppermost nozzle of the next nozzle area to which the mask data 302 is applied, and the uppermost edge of the corresponding other nozzle area. As shown in FIG. 5, the preliminary ejection pattern 400 and the mask pattern 300 are set so that printing is performed at positions 401, 402, 402, and 404 spaced apart from each other on the same line in the main scanning direction as shown in FIG. In the example of FIG. 5, the interval between the dot 401 and the dot 402 is every three dots, but a larger interval can be taken in practice.
[0044]
Note that the color of the ink that is the target of preliminary ejection on the paper is ink other than black. This is because black does not show improvement in density due to drying (or is inconspicuous), and does not need to be a target for preliminary ejection on the paper. Concentration improvement due to drying is conspicuous for yellow, magenta, and cyan, particularly light-colored light cyan and light magenta (when present). Therefore, in a preferred embodiment, the following modes are provided as operation modes related to selection of ink to be subjected to preliminary ejection on the paper surface.
(1) Mode in which all colors other than black are targeted for preliminary ejection on paper
(2) Mode in which only light colors are targeted for preliminary ejection on the page
(3) Mode that does not perform preliminary paper ejection
[0045]
The discharge state of the portion corresponding to the paper surface preliminary discharge pattern of FIG. 5 becomes a process as shown in FIG. 6 by AND processing of the print data (nozzle data) and the mask pattern 300. The black bars in this figure indicate the preliminary ejection dots on the paper ejected in that pass. The hatched portion in the drawing shows the preliminary ejection dots on the paper that have already been ejected at that time. As described above, the paper surface preliminary ejection pattern in FIG. 5 shows the static ejection result after the paper preliminary ejection, but FIG. 6 shows the change in the multi-pass printing state of the paper preliminary ejection with the passage of time in each pass. Is shown.
[0046]
FIG. 7 shows a schematic print processing flowchart according to the present embodiment. First, random mask data corresponding to the number of passes is written in the mask buffer 240 (S11). This mask data includes the mask data for pre-discharge on the paper. Next, band printing is performed according to the image data (S12), and band printing is repeatedly executed until printing of one page of image is completed (S13).
[0047]
FIG. 8 shows the internal processing of step S11 in FIG. First, basic random mask data corresponding to the number of passes is written in the mask buffer 240 (S21). Next, an OR process is performed on the basic random mask data for the ejection dot portion (black in FIG. 4) for preliminary ejection on the paper surface (S22). This means that for the basic random mask data, the black dot is forcibly set to the ejection dot (1). Further, the corresponding dot in the other pass of the ejection dot portion for preliminary ejection on the paper surface is set to the non-ejection dot (0) (S23).
[0048]
FIG. 9 shows internal processing (band processing) in step S12 of FIG. First, image data is read (S31), and preliminary paper ejection data is added to the image data (S32). Thereby, the ejection of dots corresponding to the paper preliminary ejection data pattern is performed regardless of the content of the image data. This process is repeated for one band (S33). Thereafter, the image data for one band is ANDed with a random mask pattern for multipass printing (S34). Thereafter, based on the final image data and the random mask pattern, multi-pass printing of the band is performed (S35).
[0049]
According to the present embodiment, a paper preliminary discharge pattern is added to the nozzle data, and the mask pattern is set so as not to mask portions corresponding to dots ejected in each pass of the paper preliminary discharge pattern. By doing so, all the nozzles can be discharged within a certain interval. By setting the fixed interval within a predetermined time so that the discharge state of the nozzle becomes unstable due to the fact that the ink is not discharged, the ink must be discharged before the nozzle cannot be discharged normally due to drying during printing. Is possible. As a result, an increase in ink density due to drying can be prevented, and the density of the printing result can be kept uniform.
[0050]
Although the preferred embodiments of the present invention have been described above, various modifications and changes can be made without departing from the scope of the claims other than those mentioned above.
[0051]
【The invention's effect】
In the ink jet recording method and apparatus according to the present invention, it is possible to cause all nozzles to eject ink at least at predetermined time intervals with multi-pass printing. As a result, regardless of the image data to be recorded, it is possible to prevent the ink in all the nozzles from being dried and to suppress the change in the ink density. Therefore, even for a recording head using fine nozzles, uniformity of in-page density can be maintained and image quality can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a main part of a plotter which is an example of an ink jet recording apparatus according to the present invention.
2 is a block diagram showing a schematic configuration of control hardware of the plotter shown in FIG. 1. FIG.
FIG. 3 is a diagram for explaining a relationship between a mask pattern and image data in 4-pass printing.
FIG. 4 is a diagram showing an example of a mask pattern in the embodiment of the present invention.
FIG. 5 is a diagram showing an example of a paper preliminary discharge pattern in the embodiment of the present invention.
FIG. 6 is a diagram showing a multi-pass printing process (a) to (d) of a paper preliminary discharge pattern obtained by AND processing of print data and a mask pattern.
FIG. 7 is a flowchart of schematic print processing according to the embodiment of the present invention.
FIG. 8 is a flowchart showing an internal process of step S11 in FIG.
FIG. 9 is a flowchart showing internal processing (band processing) in step S12 of FIG.
[Explanation of symbols]
10 Plotter
12 paper
14 Platen
16 Scanning rail (guide rail)
18 belt
20 Carriage
23 Image formation area
24 Transport roller
22K, 22C, 22M, 22Y Recording head
30 recovery device
32 Cap stand
32K, 32C, 32M, 32Y cap
100 Host computer (external device)
210 Image controller
221 Nozzle area
300 mask pattern
301 to 304 Mask data (masks 1 to 4)
400 Pre-discharge pattern on paper

Claims (5)

An inkjet recording method for performing multi-pass recording on the recording medium by scanning an inkjet recording head having a plurality of nozzles for recording dots of a predetermined color in a direction crossing the conveyance direction of the recording medium ,
Comprising the steps of: providing a mask pattern data corresponding to the number of passes of the multi-pass printing,
Adding dot data in accordance with a predetermined recording position pattern to image data representing an image to be recorded ;
Changing the mask pattern data so as to disperse and record the added dot data in different passes;
And a step of performing the multi-pass printing based on the dot mask pattern data data has changed the added image data and the,
The inkjet recording method , wherein the dot data is added and the mask pattern data is changed so that all of the plurality of nozzles perform recording of at least one dot in all passes of the multi-pass recording .   The recording medium is scanned by a plurality of scans of the ink jet recording head with a transport operation for transporting the recording medium by an amount smaller than the width of the ink jet recording head having a plurality of nozzles for ejecting ink of a predetermined color. An inkjet recording method for performing multi-pass recording to complete recording on a unit area of
  Preliminary ejection data for preliminarily ejecting the ink of the predetermined color to the recording medium at least once by each of the plurality of nozzles in each pass of the multipass recording is converted into image data representing an image to be recorded. A step to add to
  In the multipass printing, the preliminary ejection data is not masked so that all of the plurality of nozzles can preliminarily eject the ink of the predetermined color to the recording medium at least once in each pass of the multipass printing. Preparing the mask pattern data of
  Performing the multi-pass printing based on the image data to which the preliminary ejection data is added and the prepared mask pattern;
  An ink jet recording method comprising: An inkjet recording apparatus that performs multi-pass printing a plurality of ink jet recording head having a nozzle in the recording medium direction by scanning intersecting the transport direction of the recording medium for recording a predetermined color dot,
A memory for storing the mask pattern data for each pass of the multi-pass recording,
Adding means for adding dot data to be recorded on a recording medium in accordance with a predetermined recording position pattern to image data representing an image to be recorded ;
Changing means for changing the mask pattern data read from the memory so as to disperse and record the dot data added by the adding means in different paths ;
Control means for controlling to perform the multi-pass printing based on the image data to which dot data is added by the adding means and the mask pattern changed by the changing means ;
The adding means and the changing means add the dot data and change the mask pattern data so that all of the plurality of nozzles record at least one dot in each pass of the multi-pass printing. An inkjet recording apparatus.   The recording medium is scanned by a plurality of scans of the ink jet recording head with a transport operation for transporting the recording medium by an amount smaller than the width of the ink jet recording head having a plurality of nozzles for ejecting ink of a predetermined color. An inkjet recording apparatus that performs multi-pass recording to complete recording on a unit area of
  In each pass of the multi-pass printing, all of the plurality of nozzles are applied to the recording medium. Adding means for adding preliminary ejection data for preliminary ejection of the predetermined color ink at least once to image data representing an image to be recorded;
  In the multipass printing, the preliminary ejection data is not masked so that all of the plurality of nozzles can preliminarily eject the ink of the predetermined color to the recording medium at least once in each pass of the multipass printing. A memory storing mask pattern data of
  Control means for controlling to perform the multi-pass printing based on the image data to which the preliminary ejection data is added by the adding means and the mask pattern stored in the memory;
  An ink jet recording apparatus comprising:   The inkjet recording head further includes a plurality of nozzles for ejecting ink of a color different from the ink of the predetermined color,
  The inkjet recording apparatus according to claim 4, wherein the different color inks are not preliminarily ejected onto the recording medium.

Images