JP2007015270A - Ink jet recorder and ink jet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recorder and an ink jet recording method in which multipass recording of a visually uniform image can be carried out by convenient processing. <P>SOLUTION: Multipass recording is performed while taking account of the positional relationship between a main drop and a subdrop of different color inks ejected from a plurality of nozzle arrays. In this regard, image data recorded by respective nozzle arrays is decimated using an identical decimation mask. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method capable of recording an image in a so-called multipass recording mode.

  Ink jet recording apparatuses are widely used in printers, copiers, facsimiles, and the like as recording apparatuses used for recording images and the like, or as print output devices such as composite electronic devices including computers and word processors, and workstations. An ink jet recording apparatus performs recording by ejecting ink from a recording head toward a recording medium, and has various advantages such as easy high definition, high speed recording, excellent quietness, and low cost. have.

  In an ink jet recording apparatus, in order to improve the recording speed, a recording head in which a plurality of recording elements are integrated and arranged (hereinafter also referred to as “multihead”) is one in which a plurality of ink discharge ports and liquid paths are integrated. It is done. Further, an inkjet recording apparatus capable of recording a color image is generally provided with a plurality of such multiheads.

  FIG. 1 is an explanatory diagram of an ink jet recording head (multihead) used in a serial scan type ink jet recording apparatus capable of recording a color image. The recording heads 601, 602, and 603 for discharging cyan ink, magenta ink, and yellow ink are mounted on a carriage that can move in the main scanning direction indicated by an arrow X. When recording an image on a recording medium, the recording heads 601, 602, and 603 are moved together with the carriage in the main scanning direction, and ink is ejected from the ink ejection ports (hereinafter also referred to as “nozzles”). And the operation of conveying the recording medium in the sub-scanning direction indicated by the arrow Y intersecting the main scanning direction are repeated alternately.

  In each of the recording heads 601, 602, and 603, an even nozzle row Le and an odd nozzle row Lo are formed. The even nozzle row Le has 32 large nozzles Le (L1) to Le (L32) with a large ink discharge amount (for example, 5 pl (picoliter)) and a small ink discharge amount (for example, 2 pl). 32 small nozzles Le (S1) to Le (S32) are alternately arranged. Similarly, in the odd nozzle row Lo, 32 large nozzles Lo (L1) to Lo (L32) having a large ink discharge amount and 32 small nozzles Lo (S1) to Lo (low) having a small ink discharge amount are provided. S32) are alternately arranged. In the even nozzle row Le of each recording head, the large nozzles Le (L1) to Le (L32) and the small nozzles Le (S1) to Le (S32) each have a density (300 dpi (300 dpi)) per inch. The nozzle pitch P, which is an interval between the large nozzles and an interval between the small nozzles, is P = 1 / D = 1/300 inch≈84.7 μm. The same applies to the large nozzles Lo (L1) to Lo (L32) and the small nozzles Lo (S1) to Lo (S32) on the odd nozzle row Lo of each print head.

  Substantially, each of the recording heads 601, 602, and 603 is formed with 64 large nozzles (L) and 64 small nozzles (S) arranged at a density of 600 dpi.

  2 and 3 are explanatory diagrams in the case where an image is recorded in the 4-pass printing mode (multi-pass printing mode) using such a printing head.

  In the 4-pass printing mode of FIGS. 2 and 3, 1 / D inch square is defined as a unit recording pixel (area surrounded by a dotted line), and four ink dots are formed in the unit recording pixel. In the case of FIG. 2, the conveyance amount of the recording medium is an even multiple of 1 / D inch, while in FIG. 3, the conveyance amount of the recording medium is an even multiple of 1 / D inch. In each recording mode, there are four dot arrangement patterns shown in FIGS. 2A to 2D and FIGS. 3A to 3D.

  In the case of FIG. 2A and FIG. 3A, the first pass printing is started by the even-numbered nozzle Le when the print head moves in the forward direction of the arrow X1, and FIG. In the case of 3 (b), the first pass printing is started by the odd-numbered nozzles Lo when the print head moves in the forward direction of the arrow X1. In the case of FIGS. 2C and 3C, the first pass printing is started by the even-numbered nozzle Le when the print head moves in the backward direction indicated by the arrow X2, and FIGS. In the case of FIG. 3D, printing in the first pass is started by the odd-numbered nozzle Lo when the recording head moves in the backward direction indicated by the arrow X2.

  2 and 3, the ink ejection direction of the even-numbered nozzle Le is inclined in the arrow E direction (X1 direction), and the ink ejection direction of the odd-numbered nozzle Lo is inclined in the arrow O direction (X2 direction). And Further, it is assumed that printing is performed by using even-numbered large nozzles Le and odd-numbered large nozzles Lo.

  2 and 3, E1, O1 and e1, o1 are the main and sub dots formed in the first pass by the nozzles Le and Lo, and E2, O2 and e2, o2 are the second pass by the nozzles Le and Lo. The main dots and sub-dots E3, O3 and e3, o3 are formed in the third pass by the nozzles Le and Lo, and E4, O4 and e4 and o4 are 3 by the nozzles Le and Lo. Main dots and sub dots formed in the pass. The main dot is formed by the main droplet of ink ejected from the nozzle, and the sub dot is separated from the main droplet and is smaller than the main droplet (hereinafter referred to as “sub-drop” or “satellite”). Formed).

  Actually, the main dots formed in the first pass to the fourth pass are overlapped, and in FIGS. 2 and 3, the main dots in the first pass to the fourth pass are different from each other in the single recording pixel for convenience of explanation. Shown to be formed in position.

  In the case of FIG. 2, since the recording medium is transported by an even multiple of 1 / D inch during each recording scan (from the first pass to the fourth pass), all the dots in the unit recording pixel are used. Is formed by the even-numbered nozzle Le or the odd-numbered nozzle Lo. 2A and 2B (or FIG. 2C and FIG. 2D) appear alternately every 1 / D inch in the sub-scanning direction. On the other hand, in the case of FIG. 3, the recording medium is conveyed by an odd multiple of 1 / D inch during each recording scan (from the first pass to the fourth pass). It is formed by alternately using even-numbered nozzles Le and odd-numbered nozzles Lo. Then, the patterns of FIG. 3A and FIG. 3B (or FIG. 3C and FIG. 3D) appear alternately every 1 / D inch in the sub-scanning direction.

  Normally, satellites have a lower ejection speed than main dots, so the time from when they are ejected until they land on the recording medium is longer than the time from when the main dots are ejected until they land on the recording medium. . Further, the moving speed of the recording head in the scanning direction is added to the ejection speed of the main dots and satellites.

  In either case of FIG. 2 or FIG. 3, when the recording head moves in a direction in which the ink ejection direction is inclined, the sub-dots may be formed at a position away from the main dots. Therefore, in the case of FIG. 2, the pixel of FIG. 2A (or FIG. 2C) in which the sub dot is formed on the right side of the main dot and the sub dot in the right side of the main dot are formed in FIG. b) (or FIG. 2D) pixels appear alternately every 1 / D inch in the sub-scanning direction. Therefore, a visually non-uniform image is recorded. On the other hand, in the case of FIG. 3, the pixel of FIG. 2A (or FIG. 2D) in which sub-dots are formed on the left and right of the main dot, and FIG. 2 (c)) pixels appear alternately every 1 / D inch in the sub-scanning direction. Therefore, a visually non-uniform image is recorded.

  In order to solve such a problem, Patent Document 1 proposes a method for performing control so that even-numbered conveyance of 1 / D inch and odd-numbered conveyance of a recording medium are included at least once. Yes. According to this method, it is possible to record a visually uniform image by making the shift amount of the sub-dot formation position as uniform as possible. More specifically, the multi-pass printing is performed by sequentially repeating the even-numbered conveyance of 1 / D inch and the odd-numbered conveyance of the recording medium, so that the even-numbered nozzle and the odd-numbered nozzle are placed on the left and right of the main dot. A pixel in which each ejected sub dot appears is recorded.

JP 2003-053962 A

  However, the method described in Patent Document 1 is extremely complicated to control because of the restriction of including even-numbered conveyance of 1 / D inch and odd-numbered conveyance of the recording medium at least once. . Usually, a motor for conveying a recording medium does not guarantee accuracy with respect to all the conveyance amounts regardless of a DC motor or a pulse motor. For example, although accuracy can be obtained with an integral multiple of the basic unit of the carry amount, accuracy may not be obtained with other carry amounts. Therefore, it is necessary to determine the odd number times and even number times the 1 / D inch of the recording medium in consideration of the characteristics of the motor for conveying the recording medium, and the control becomes complicated and the design is free. The degree is low. Further, depending on the setting of the conveyance amount of the recording medium, all the nozzles cannot be used.

  An object of the present invention is to provide an ink jet recording apparatus and an ink jet recording method capable of performing multipass recording of a visually uniform image by simple processing.

  The ink jet recording apparatus of the present invention uses a recording head in which a plurality of nozzles capable of ejecting ink are arranged at a predetermined pitch, and performs forward scanning and returning of the recording head along a main scanning direction intersecting with the nozzle arrangement direction. An ink jet recording apparatus capable of recording an image in a predetermined recording area on a recording medium with ink ejected from the nozzles of the recording head with at least one scan, each of the recording heads having a different color Including a plurality of nozzle rows in which the positional relationship between the main droplet and the sub-droplet of the ink to be discharged is different in the forward scan and the backward scan, and in at least one of the forward scan and the backward scan, Different color inks can be ejected, and the positional relationship between the main droplet and the sub-droplet in the forward scanning and the backward scanning is different from each other. A recording control unit that performs recording using two or more nozzle rows; and a mask unit that thins out image data to be recorded by the two or more nozzle rows using the same thinning mask. To do.

  The inkjet recording method of the present invention uses a recording head in which a plurality of nozzles capable of ejecting ink are arranged at a predetermined pitch, and performs forward scanning and returning of the recording head along a main scanning direction intersecting with the nozzle arrangement direction. An inkjet recording method for recording an image in a predetermined recording area on a recording medium with ink ejected from the nozzles of the recording head with at least one scan, each of the recording heads having a different color Ink discharge is possible, and the positional relationship between the main and sub-droplets of ink to be discharged includes a plurality of nozzle rows that differ in the forward scan and the backward scan, and is different in at least one of the forward scan and the backward scan The color ink can be ejected, and the positional relationship between the main droplet and the sub-droplet in the forward scanning and the backward scanning is different 2 And performing recording by using the nozzle array, the more, using the same thinning mask, characterized in that it comprises a, a step of thinning out the image data to be recorded by the two or more nozzle arrays.

  According to the present invention, multi-pass printing is performed in consideration of the positional relationship between the main droplets and sub-droplets of different colors ejected from a plurality of nozzle rows, and image data recorded by each nozzle row at that time By using the same thinning mask, the recording including the sub-dots formed by the ink satellites is performed when recording is performed using a plurality of colors of ink without performing complicated processing as in the prior art. As a result, a visually uniform image can be multipass-recorded by simpler processing.

  In addition, the amount of mask data can be reduced by thinning out the recording data corresponding to the inks of a plurality of colors using the same mask. As a result, the capacity of the ROM or the like holding the mask data is reduced, and the apparatus Cost reduction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
"Mechanical structure of inkjet recording device"
FIG. 4 is a schematic perspective view of an ink jet recording apparatus to which the present invention can be applied.

  In FIG. 4, reference numeral 1101 denotes four ink jet cartridges. These are composed of an ink tank in which black, cyan, magenta, and yellow ink are respectively stored, and a recording head (multi-head) 713 corresponding to each ink. In the recording head 713, d nozzles 1201 are arranged at a density of D per inch. The paper feed roller 1103 rotates while holding the recording medium P together with the auxiliary roller 1104 to convey the recording medium P in the sub-scanning direction (conveying direction) indicated by the arrow Y. A pair of paper feed rollers 1105 feeds the recording medium P. The pair of rollers 1105 rotate while holding the recording medium P, similarly to the rollers 1103 and 1104. The pair of paper feed rollers 1105 can apply tension to the recording medium P by making the rotational speed lower than that of the paper feed rollers 1103.

  Reference numeral 1106 denotes a carriage on which four ink jet cartridges 1101 can be mounted, and is movable in the main scanning direction indicated by an arrow X. The carriage 1106 waits at the home position h at the position indicated by the broken line in the figure when recording is not being performed or when recovery processing (processing for maintaining ink ejection performance) of the recording head 713 is performed. .

  In the 1-pass recording mode, the following recording operation is performed.

  First, the carriage 1106 positioned at the home position h before the start of recording moves in the main scanning direction together with the ink jet cartridge 1101 when the recording start command is issued. During the movement, the recording head 713 performs recording with a width of d / D inches on the recording medium P by ejecting ink from d nozzles arranged at a density of D per inch. . The recording medium P is conveyed in the sub-scanning direction by a width of d / D inches by rotating the paper feed roller 1103 in the direction of the arrow before the second recording starts after the end of the first recording. As described above, in the one-pass recording mode, the recording of the d / D inch width by the recording head 713 and the conveyance of the recording medium corresponding to the d / D inch width are repeated for each main scan of the carriage 1106. By doing so, for example, the recording for one page of the recording medium P is completed.

  In the multi-pass recording mode, a recording operation as described later is performed. The multi-pass recording mode is optimal for recording a photographic image with high quality.

"Control system configuration"
FIG. 5 is a block diagram showing a configuration of a control system in the ink jet recording apparatus of FIG.

  The CPU 700 executes control and data processing of each component described later via the main bus line 705. That is, the CPU 700 controls head drive control, carriage drive control, and data processing, which will be described later, via each component according to a program stored in the ROM 702. The RAM 701 is used as a work area for data processing by the CPU 700, and a hard disk or the like can also be used.

  The image input unit 703 has an interface with a host device (not shown) such as a personal computer, and temporarily holds image data input from the host device. The image signal processing unit 704 executes data processing in addition to color conversion and binarization. The operation unit 706 is provided with keys and the like, and enables control input by the operator. The recovery system control circuit 707 controls a recovery operation for maintaining a good ink ejection state in the recording head 713 in accordance with a recovery processing program stored in the RAM 701. In the recovery operation, the recovery system motor 708 drives the cleaning blade 709, the cap 710, and the suction pump 711. As recovery operations, preliminary ejection for ejecting ink that does not contribute to image recording from the recording head 713 into the cap 710, suction recovery operation for attracting and discharging ink that does not contribute to image recording from the recording head 713 into the cap 710, and This includes an operation of wiping the formation surface of the ink discharge port in the recording head 713 with the cleaning blade 709.

  The head drive control circuit 715 controls an electrothermal transducer (heater) as an energy generating means for discharging ink in the recording head 713, and discharges ink for recording from nozzles or ink for recovery operation. Is preliminarily discharged from the nozzle. As the energy generating means, a piezo element or the like can be used. When the electrothermal transducer is used as in this example, the ink can be foamed by the thermal energy generated by the electrothermal converter, and the ink can be ejected from the nozzle using the foaming energy. The carriage drive control circuit 716 and the paper feed control circuit 717 control the movement of the carriage 1106 and the paper feed (conveyance) of the recording medium P according to a program.

  In the recording head 713, the substrate on which the energy generating means for ejecting ink is provided is provided with a heat retaining heater for adjusting the temperature of the ink in the recording head 713 to a desired set temperature. The substrate of the recording head 713 is provided with a thermistor 712 for measuring the ink temperature substantially inside the recording head. The heat retaining heater and the thermistor 712 may be provided outside the substrate of the recording head 713, or may be provided near the periphery of the recording head.

"Recording head configuration"
6 to 8 are diagrams for explaining a configuration example of the recording head 713.

  In FIG. 6, 713C is a recording head for discharging cyan ink, 713M is a recording head for discharging magenta ink, and 713Y is a recording head for discharging yellow ink. In each of the recording heads 713 (713C, 713M, 713Y), an even nozzle row Le and an odd nozzle row Lo are formed.

  In the recording head 713C, the even nozzle row Le has 64 small nozzles Le (S1) to Le (S64) with a small ink discharge amount (for example, 2 pl (picoliter)) D = 600 per inch. Are arranged at a density of 600 dpi. Also, in the odd nozzle row Lo, the density of D = 600 dots per inch (600 dpi (dots / inch)) of 64 large nozzles Lo (L1) to Lo (L64) having a large ink discharge amount (for example, 5 pl). )). The space between these large nozzles (nozzle pitch) P and the space between the small nozzles (nozzle pitch) P are P = 1 / D = 1/600 inch≈42.4 μm. Thus, the recording head 713C having d = 64 ejection ports (64 nozzles) in a row has a length (d / D) of d / D = 64/600 inches≈2.71 mm.

  Contrary to the recording head 713C, the other two recording heads 713M and 713Y have 64 large nozzles Le (L1) to Le (L64) arranged in the even nozzle row Le and 64 in the odd nozzle row Lo. Small nozzles Le (S1) to Le (S64) are arranged. Conditions such as nozzle density, nozzle spacing, and number of nozzles in the two recording heads 713M and 713Y are the same as those of the recording head 713C. These recording heads 713 (713C, 713M, 713Y) are arranged side by side in the main scanning direction.

  7 is an enlarged view of a part of the recording head 713C, and FIG. 8 is an enlarged cross-sectional view taken along line VIII-VIII in FIG.

  In FIG. 8, reference numeral 1001 denotes an ink supply port, 1002 denotes a foaming chamber, and 1004 denotes the surface of the recording head. 1003A is an electrothermal transducer (heater) that generates thermal energy for ejecting ink from the large nozzle Lo (L60), and 1000B generates thermal energy for ejecting ink from the small nozzle Le (S60). An electrothermal transducer (heater). Large nozzles are arranged on one side (left side in the figure) of the common liquid chamber 1005 to which ink is supplied from the ink supply port 1001, and small nozzles are arranged on the other side (right side in the figure). By integrating the large nozzle and the small nozzle on one side and the other side of the common liquid chamber 1005 in this way, the ink ejection direction is unified for each large nozzle, and the ink ejection direction is unified for each small nozzle. Is possible.

  In the following description, in each of the recording heads 713C, 713M, and 713Y, the nozzles arranged in the even nozzle row Le have the ink droplet ejection direction inclined in the direction of the arrow E and arranged in the odd nozzle row Lo. It is assumed that the ejected nozzle is inclined in the direction of arrow O in the ink droplet ejection direction.

  The arrangement form of the nozzles is not specified in the above example and is arbitrary. The nozzles are arranged at a density of D ′ per inch (D′ dpi), and the nozzle pitch P ′ (P ′ = 1 / D ′) do it. In this case, the resolution of one pulse of the pulse motor for driving the paper feed roller that conveys the recording medium P is equivalent to D ′ dots (D′ dpi) per inch in terms of the conveyance amount of the recording medium P, or It may be a multiple.

"Multipass recording mode"
Next, the recording operation in the multipass recording mode will be described. As described above, the recording apparatus of this example can also perform a recording operation in the 1-pass recording mode.

  In the multi-pass printing mode, the nozzle array of the printing head is divided into m, and an image in a predetermined area is completed by m printing scans. In the following, as an example of the multi-pass printing mode, a description will be given by taking as an example a 2-pass printing mode in which m = 2, the nozzle array of the printing head is divided into two, and an image of a predetermined area is completed by two printing scans. To do. The two-pass recording mode is an example, and the recording apparatus of the present embodiment can also perform a recording operation in a multi-pass recording mode of three or more passes. In the 2-pass printing mode, the paper feed amount for each pass is 1/2 of the nozzle length (nozzle row length), that is, 32/600 inches.

  In the present embodiment, it is assumed that print data corresponding to cyan, magenta, and yellow ink is thinned using the same thinning mask pattern. Therefore, for example, when there is print data corresponding to cyan and magenta ink in the same print pixel, the print pixel is printed by the same print scan (same pass).

  Hereinafter, a recording method in the 2-pass recording mode will be described mainly with reference to FIG.

  FIG. 9 shows a case where 1/600 inch square is a unit recording pixel and ink is ejected from the large nozzles of the recording heads 713C and 713M to form large dots C and M of cyan and magenta ink on the unit recording pixel. It is an example. FIGS. 9A and 9B are different examples in the case where two large dots C and M are formed on the unit recording pixel by two scans. FIGS. 9C and 9D are as follows. This is a different example in the case of forming one large dot C, M at a unit recording pixel by one scanning. Although these large dots C and M are actually formed to overlap, in FIG. 9, for the convenience of explanation, these large dots are expressed as if they are shifted in the vertical direction.

  In the case of FIG. 9A, the first pass printing starts by the forward scanning (forward scanning) in which the recording head moves in the forward direction of the arrow X1. In the first pass in the X1 direction, ink is ejected from the cyan ink ejection nozzles on the odd nozzle row Lo and the magenta ink ejection nozzles on the even nozzle row Le, resulting in large dots of cyan and magenta ink. It is formed so that C and M overlap. Let these large dots C and M be C (O1) and M (E1). In the case of this example, the nozzles on the even nozzle row Le are inclined in the direction of the arrow E, which is the same as the direction of the arrow X1, and the nozzles on the odd nozzle row Lo have the ink droplet ejection direction. It is inclined in the direction of arrow O, which is the same as the direction of arrow X2.

  As described above, when the ink discharge direction of the nozzle is inclined, when the recording head moves in the inclination direction, the main dot formed by the main droplet of ink discharged from the nozzle is The position of the sub-dot formed by the satellite (sub-drop) discharged from the nozzle is shifted. Therefore, in this first pass, the cyan ink main droplet and satellite land at close positions, and the magenta ink main droplet and satellite land at separate positions. In FIG. 9A, the sub-dot formed by the magenta ink satellite is m (E1).

  When such first-pass recording is completed, the recording medium P is conveyed 32/600 inches, and the next second-pass recording is performed.

  The second pass printing is performed by backward scanning (reverse scanning) in which the recording head moves in the backward direction indicated by the arrow X2. Also in the second pass backward scan, ink is ejected from the cyan ink ejection nozzles on the odd nozzle row Lo and the magenta ink ejection nozzles on the even nozzle row Le, as in the previous first pass scanning. Are ejected to form large dots C and M of cyan and magenta inks. Let these large dots C and M be C (O2) and M (E2). In the second pass, contrary to the first pass, the cyan ink main droplet and the satellite land at a distant position, and the magenta ink main droplet and the satellite land at a close position. In FIG. 9A, the sub dot formed by the cyan ink salite is c (O2).

  The recording on the unit recording pixel is completed by such two passes. For example, in the case where the nozzle Lo (L2) of the recording head 713C and the nozzle Le (L2) of the recording head 713M are used in the first pass for recording on the unit recording pixel, the recording medium P is 32 after that. Since the nozzle is transported, the nozzle Lo (L34) of the recording head 713C and the nozzle Le (L34) of the recording head 713M are used in the second pass.

  By recording an image as shown in FIG. 9A, the left and right sides of C (O1), M (E1), C (O2), and M (E2) of the four main dots formed to overlap the unit recording pixel. In addition, the satellite sub-dots m (E1) and c (O2) are evenly formed one by one.

  In the case of FIG. 9B, the first pass printing starts by the backward scanning in which the recording head moves in the backward direction indicated by the arrow X2. In the first pass in the X2 direction, ink is ejected from the cyan ink ejection nozzles on the odd nozzle row Lo and the magenta ink ejection nozzles on the even nozzle row Le, resulting in large dots of cyan and magenta ink. It is formed so that C and M overlap. Let these large dots C and M be C (O1) and M (E1). In the first pass, the cyan ink main droplet and the satellite land at a distant position, and the magenta ink main droplet and the satellite land at a close position. In FIG. 9B, the sub-dot formed by the salite of the former cyan ink is assumed to be c (O1).

  When such first-pass recording is completed, the recording medium P is conveyed 32/600 inches, and the next second-pass recording is performed.

  The second pass printing is performed by forward scanning in which the recording head moves in the forward direction of arrow X1. Also in the forward pass scanning of the second pass, ink is ejected from the cyan ink ejection nozzles on the odd nozzle row Lo and the magenta ink ejection nozzles on the even nozzle row Le, as in the previous backward pass scanning. Are ejected to form large dots C and M of cyan and magenta inks. Let these large dots C and M be C (O2) and M (E2). In the second pass, contrary to the first pass, the cyan ink main droplet and the satellite land at close positions, and the magenta ink main droplet and the satellite land at separate positions. In FIG. 9A, the sub-dot formed by the magenta ink salite is m (E2).

  The recording on the unit recording pixel is completed by such two passes. For example, in the case where the nozzle Lo (L3) of the recording head 713C and the nozzle Le (L3) of the recording head 713M are used in the first pass for recording on the unit recording pixel, the recording medium P is 32 after that. Since the nozzles are conveyed, the nozzle Lo (L35) of the recording head 713C and the nozzle Le (L35) of the recording head 713M are used in the second pass.

  By recording an image as shown in FIG. 9B, the left and right sides of C (O1), M (E1), C (O2), and M (E2) of the four main dots formed to overlap the unit recording pixel. In addition, the satellite sub-dots c (O1) and m (E2) are uniformly formed one by one.

  In the case of FIG. 9C, large dots C and M of cyan and magenta ink are applied to the unit recording pixels only by one forward scanning (one pass) in which the recording head moves in the forward direction of the arrow X1. Form to overlap. In the case of FIG. 9C, the large dot C of cyan and magenta ink is applied to the unit recording pixel by only one backward scanning (one pass) in which the recording head moves in the backward direction indicated by the arrow X2. It forms so that M may overlap. The case of FIG. 9C corresponds to the case where large dots C and M of cyan and magenta are formed one by one in the first pass in FIG. 9A, and therefore one sub dot m (E1). Will be formed. 9D corresponds to the case where large dots C and M of cyan and magenta are formed one by one in the first pass in FIG. 9B, so that one sub dot c ( O1) will be formed.

  It should be noted that when one large cyan and magenta dot C, M is to be formed on the same unit recording pixel, at least one sub dot can be formed by at least one satellite. That is.

  In the above example, cyan and magenta inks have been described. The reason is that yellow ink has high lightness, and even if sub-dots are formed by satellites, the influence on image quality is small. Therefore, in this example, the nozzle arrangement of the recording head 713Y for yellow ink is the same as that of the recording head 713M for magenta ink. However, the nozzle arrangement of the recording head 713Y may be the same as that of the recording head 713C for cyan ink.

(Other embodiments)
In the above-described embodiment, small nozzles Le (S1) to Le (S64) for cyan ink and large nozzles Le (L1) to Le (L64) for magenta ink are arranged in the even nozzle row Le, and odd nozzles. In the row Lo, large nozzles Lo (L1) to Lo (L64) for cyan ink and small nozzles Lo (S1) to Lo (S64) for magenta ink are arranged. On the contrary, a large nozzle for cyan ink and a small nozzle for magenta ink are arranged in the even nozzle row Le, and a small nozzle for cyan ink and a large nozzle for magenta ink are arranged in the odd nozzle row Lo. May be. That is, for the large nozzles for cyan ink and magenta ink, one may be arranged in the even nozzle row Le and the other in the odd nozzle row Lo. Similarly, for the small nozzles for cyan ink and magenta ink, One of these may be arranged in the even nozzle row Le and the other in the odd nozzle row Lo. In short, the large dots of cyan and magenta ink and their sub-dots have the same relationship as in the above-described embodiment, and similarly, the small dots of cyan and magenta ink and their sub-dots have the same relationship as in the above-described embodiment. If it becomes. Such a relationship only needs to be established for two different colors of ink, and the ink colors are not limited to cyan and magenta.

  FIG. 10 is a diagram for explaining another configuration example of the recording head.

  The recording head of this example has a nozzle configuration in which small nozzles are excluded from the recording head of FIG. 6 described above and only large nozzles are provided. Since the large dot and its sub-dot are in a relationship with the embodiment described above, the same effects as those of the embodiment described above can be obtained. Reference numeral 1001 denotes an ink supply port similar to that of the recording head in the above-described embodiment.

  The present invention can be applied not only to the 2-pass printing mode but also to a multi-pass printing mode of 3 or more passes.

  In addition to the nozzle configuration as described above, the print data corresponding to all ink colors is thinned using the same thinning mask, so that complicated data processing as in the prior art is not performed. For example, when recording blue with cyan and magenta inks, it is possible to always include sub-dots, and an image almost equivalent to the conventional one can be recorded by a simpler method. In addition, by making the thinning mask the same for each ink color, it is possible to reduce the amount of mask data related to the thinning mask as compared with the conventional case. As a result, the ROM capacity for holding the mask data can be reduced, and the cost of the entire apparatus can be reduced.

(Other)
The above-described embodiment includes, among inkjet recording methods, in particular, a means (for example, an electrothermal converter or a laser beam) that generates thermal energy as energy used for ink ejection, and the ink is generated by the thermal energy. By using a method for causing the state change, it is possible to achieve high density and high definition of the recorded image.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both a so-called on-demand type and a continuous type. In the case of the on-demand type, the temperature rises rapidly corresponding to the recorded information and exceeding the nucleate boiling in the electrothermal transducer arranged corresponding to the sheet (liquid) holding the liquid (ink) and the liquid path At least one drive signal is applied. As a result, thermal energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. As a result, bubbles are generated in the liquid (ink) corresponding to the drive signal on a one-to-one basis. Form. Due to the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. By making such a drive signal into a pulse shape, it is possible to immediately and appropriately perform bubble growth and contraction, and it is possible to achieve discharge of liquid (ink) having particularly excellent responsiveness.

  As such a pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (straight liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the thermal action The configurations described in US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the surface is arranged in a bent region, are also included in the present invention. In addition, for a plurality of electrothermal transducers, Japanese Patent Laid-Open No. 59-123670 that discloses a configuration in which a common slot is used as a discharge portion of an electrothermal transducer, or an opening that absorbs a pressure wave of thermal energy. A configuration based on Japanese Patent Application Laid-Open No. 59-138461 disclosing a configuration corresponding to the discharge unit may be adopted.

  Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, a combination of a plurality of recording heads as disclosed in the above-mentioned specification is used. Either a satisfying configuration or a configuration as a single recording head formed integrally may be used.

  As the recording head, not only the cartridge type recording head in which the ink tank is integrally provided in the recording head itself described in the above embodiment, but also the recording head can be electrically connected to the apparatus main body. Alternatively, a replaceable chip type recording head that can be connected and supply ink from the apparatus main body may be used.

  In addition, it is preferable to add recovery means for the recording head, preliminary means, and the like to the configuration of the recording apparatus described above because the recording operation can be further stabilized. Specific examples include a capping unit, a cleaning unit, a pressurizing or suction unit, a preheating unit, and the like for the recording head. As the preheating means, an electrothermal converter, a heating element different from this, or a combination thereof can be used. In addition to recording, providing a preliminary ejection mode for ejecting ink is also effective for performing stable recording.

  Furthermore, as a recording apparatus, not only a recording mode of only a mainstream color such as black, but also a recording mode of multi-color images of different colors or a mixed color irrespective of an integrated configuration of a recording head or a combination of a plurality of recording heads. It is also possible to provide an apparatus provided with at least one of full-color image recording modes.

  In the embodiment described above, the description is made on the assumption that the ink is a liquid. However, ink that solidifies at or below room temperature may be used that softens or liquefies at room temperature. Alternatively, in the ink jet system, since the temperature of the ink itself is generally adjusted within a range of 30 ° C. or more and 70 ° C. or less, and the temperature is controlled so that the viscosity of the ink falls within the stable discharge range, the recording is performed. Any ink may be used as long as the ink is in a liquid state when a signal is applied.

  In addition, the temperature rise by heat energy may be positively used as the energy for changing the state of the ink from the solid state to the liquid state. In order to prevent the ink from evaporating, it is solidified in the state of standing and liquefied by heating. Ink may be used. In any case, by applying thermal energy according to the recording signal, the ink is liquefied and ejected, or the ink already starts to solidify when reaching the recording medium. The present invention can also be applied to the case of using ink having the property of liquefying for the first time. In such a case, the ink is held in a liquid or solid state in a recess or a through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. In addition, it is good also as a form which opposes an electrothermal converter. In the present invention, the most effective method for such various inks is the film boiling method as in the above-described embodiment.

  In addition, as a form of the recording apparatus according to the present invention, as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader (reading apparatus) or the like, in addition to an image output terminal provided integrally or separately thereto, Further, it may be in the form of a facsimile machine having a transmission / reception function.

FIG. 10 is a schematic diagram for explaining a nozzle configuration of a recording head provided in a conventional recording apparatus. FIG. 2 is a schematic diagram illustrating an example of dot arrangement when an image is recorded in a 4-pass recording mode by a conventional recording apparatus including the recording head of FIG. 1. FIG. 10 is a schematic diagram illustrating another example of dot arrangement when an image is recorded in a 4-pass recording mode by a conventional recording apparatus including the recording head of FIG. 1. 1 is a perspective view of a main part of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 5 is a block configuration diagram of a control system of the ink jet recording apparatus of FIG. 4. FIG. 5 is a schematic diagram for explaining a nozzle configuration of a recording head used in the ink jet recording apparatus of FIG. 4. FIG. 7 is an enlarged view of a part of the recording head in FIG. 6. It is an expanded sectional view which follows the VIII-VIII line of FIG. Each of (a), (b), (c), and (d) is a schematic diagram showing an example of different dot arrangements when an image is recorded in the two-pass recording mode by the ink jet recording apparatus of FIG. It is a schematic diagram for demonstrating the other example of the nozzle structure of the recording head used for the inkjet recording device of this invention.

Explanation of symbols

1106 Carriage 700 CPU
701 ROM
702 RAM
704 Image signal processing unit 713 Recording head 713C Cyan ink recording head 713M Magenta ink recording head 713Y Yellow ink recording head 715 Head drive control circuit 716 Carriage drive circuit 717 Paper feed drive circuit Lo Odd nozzle row Le Even nozzle row L1 L64 large nozzles S1 to S64 small nozzles C cyan ink large dots c cyan ink sub-dots M magenta ink large dots m magenta ink sub-dots O Ink ejection gradient direction of nozzles on odd nozzle rows E even nozzle rows Ink discharge inclination direction of X nozzles X Main scanning direction X1 Forward direction (forward direction)
X2 Return direction (return direction)
Y Sub-scanning direction (transport direction)
P Recording medium

Claims (9)

A recording head in which a plurality of nozzles capable of ejecting ink are arranged at a predetermined pitch is used, and at least one forward scanning and backward scanning of the recording head along the main scanning direction intersecting the nozzle arrangement direction are performed. An ink jet recording apparatus capable of recording an image in a predetermined recording area on a recording medium with ink ejected from a nozzle of the recording head,
The recording head includes a plurality of nozzle rows that are capable of ejecting inks of different colors, and in which the positional relationship between the main droplets and sub-droplets of the ejected ink is different in the forward scan and the backward scan,
Two or more nozzle rows that are capable of ejecting inks of different colors in at least one of the forward scan and the backward scan, and in which the positional relationship between the main droplet and the sub-droplet in the forward scan and the backward scan is different from each other; Recording control means for recording using
Mask means for thinning out image data to be recorded by the two or more nozzle rows using the same thinning mask;
An ink jet recording apparatus comprising: The two or more nozzle rows include first and second nozzle rows capable of ejecting first and second inks of different colors,
The primary ink droplet and the secondary ink droplets ejected from the first nozzle row overlap and land on the recording medium in forward scanning, and separate and land on the recording medium in forward scanning. And
The main and sub-drops of the second ink ejected from the second nozzle row land separately on the recording medium during forward scanning, and overlap and land on the recording medium during forward scanning. The inkjet recording apparatus according to claim 1, wherein: The first nozzle row is located on one side in the main scanning direction with respect to the first ink supply port to which the first ink is supplied,
The inkjet recording according to claim 2, wherein the second nozzle row is located on the other side in the main scanning direction with respect to a second ink supply port to which the second ink is supplied. apparatus.   At least one of the first and second nozzle arrays is one of two nozzle arrays that are located on both sides in the main scanning direction with respect to the ink supply port and have different ink ejection amounts. The inkjet recording apparatus according to claim 3.   5. The at least one of the first and second nozzle rows is a nozzle row having a larger ink discharge amount out of two nozzle rows having different ink discharge amounts. 6. Inkjet recording apparatus. The first nozzle row is a nozzle having a larger ink discharge amount among two nozzle rows that are located on both sides in the main scanning direction with respect to the first ink supply port and have different ink discharge amounts. And
The second nozzle row is located on both sides in the main scanning direction with respect to the second ink supply port, and the nozzle having the larger ink discharge amount among the two nozzle rows having different ink discharge amounts. And
In the main scanning direction, the arrangement order of the two nozzle rows that are located on both sides of the first ink supply port and have different ink ejection amounts, and that are located on both sides of the second ink supply port The ink jet recording apparatus according to claim 5, wherein the arrangement order of the two nozzle arrays having different ejection amounts is opposite. On both sides of the first ink supply port, a large nozzle with a large ink discharge amount and a small nozzle with a small ink discharge amount are located.
On both sides of the second ink supply port, a large nozzle with a large ink discharge amount and a small nozzle with a small ink discharge amount are located.
In the main scanning direction, large nozzles and small nozzles on both sides of the first ink supply port are arranged in that order, and small nozzles and large nozzles on both sides of the second ink supply port are arranged in that order. The inkjet recording apparatus according to claim 6. On both sides of the first ink supply port, a large nozzle with a large ink discharge amount and a small nozzle with a small ink discharge amount are located.
On both sides of the second ink supply port, a large nozzle with a large ink discharge amount and a small nozzle with a small ink discharge amount are located.
In the main scanning direction, small nozzles and large nozzles on both sides of the first ink supply port are arranged in that order, and large nozzles and small nozzles on both sides of the second ink supply port are arranged in that order. The inkjet recording apparatus according to claim 6. A recording head in which a plurality of nozzles capable of ejecting ink are arranged at a predetermined pitch is used, and at least one forward scanning and backward scanning of the recording head along the main scanning direction intersecting the nozzle arrangement direction are performed. An ink jet recording method for recording an image in a predetermined recording area on a recording medium with ink ejected from the nozzles of the recording head,
The recording head includes a plurality of nozzle rows that are capable of ejecting inks of different colors, and in which the positional relationship between the main droplets and sub-droplets of the ejected ink is different in the forward scan and the backward scan,
Two or more nozzle rows that are capable of ejecting inks of different colors in at least one of the forward scan and the backward scan, and in which the positional relationship between the main droplet and the sub-droplet in the forward scan and the backward scan is different from each other; A process of recording using
Using the same thinning mask, thinning image data to be recorded by the two or more nozzle rows;
An ink jet recording method comprising:

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