JP2004330794A - Dot recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preferable dot recording system being suitable for an individual dot recording device. <P>SOLUTION: A plurality of dot recording modes which can utilize a printer are classified into a plurality of recording mode groups on every combination of a recording resolution and a recording speed. In the initial setting of the dot recording device, one among a plurality of recording mode groups is selected. In addition, a plurality of the recording mode groups related to at least one recording resolution contain more dot recording modes as the recording speed is slower. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for recording dots on the surface of a print medium using a dot recording head.

  Examples of a recording apparatus that performs recording while a recording head scans in a main scanning direction and a sub-scanning direction include a serial scan printer and a drum scan printer. As one of the techniques for improving the image quality in this type of printer, particularly an ink jet printer, an "interlace method" disclosed in U.S. Pat. No. 4,198,642 and JP-A-53-2040 is disclosed. There is a technology called.

  FIG. 12 is an explanatory diagram illustrating an example of the interlacing method. In this specification, the following are used as parameters that define the recording method.

N: Number of nozzles [pcs],
k: Nozzle pitch [dot],
s: number of scan repetitions,
D: Nozzle density [pcs / inch],
L: Sub-scan feed amount [dot] or [inch],
w: Dot pitch [inch].

  The number of nozzles N [number] is the number of nozzles used for forming dots. In the example of FIG. 12, N = 3. The nozzle pitch k [dot] indicates how many nozzle pitches of the print head are equal to the pitch (dot pitch w) of the print image. In the example of FIG. 12, k = 2. The number of scan repetitions s [times] is a number indicating the number of main scans in which each main scan line is filled with dots. Hereinafter, the main scanning line is referred to as “raster”. In the example of FIG. 12, since each raster is filled in one main scan, s = 1. As described later, when s is 2 or more, dots are formed intermittently along the main scanning direction. The nozzle density D [pieces / inch] indicates how many nozzles are arranged per inch in the nozzle array of the print head. The sub-scan feed amount L [dot] or [inch] indicates the distance moved by one sub-scan. The dot pitch w [inch] is a dot pitch in a recorded image. Generally, w = 1 / (D · k) and k = 1 / (D · w) hold.

  In FIG. 12, circles including two-digit numbers indicate dot recording positions. As shown in the legend at the lower left of FIG. 12, among the two-digit numbers in the circle, the numbers on the left indicate the nozzle numbers, and the numbers on the right indicate the recording order (the number of main scans Has been shown).

  The interlace method shown in FIG. 12 is characterized by the configuration of the nozzle array of the recording head and the sub-scanning method. That is, in the interlace method, the nozzle pitch k indicating the center point interval between the adjacent nozzles is set to an integer of 2 or more, and the number of nozzles N and the nozzle pitch k are selected to be integers having a prime relationship. The sub-scan feed amount L is set to a constant value given by N / (D · k).

  The interlace method has an advantage that variations in nozzle pitch, ink ejection characteristics, and the like can be dispersed on a printed image. Therefore, even if there is a variation in the nozzle pitch and the discharge characteristics, the effect is obtained that the effects can be reduced and the image quality can be improved.

  As another technique for improving image quality in a color ink jet printer, there is a technique called "overlap method" or "multi-scan method" disclosed in Japanese Patent Application Laid-Open No. Hei 3-207665 and Japanese Patent Publication No. Hei 4-19030. .

  FIG. 13 is an explanatory diagram illustrating an example of the overlap method. In the overlap method, eight nozzles are classified into two nozzle groups. The first set of nozzle groups is composed of four nozzles with even nozzle numbers (the number on the left side of the circle), and the second set of nozzle groups is with four odd nozzle numbers. It is composed of nozzles. In one main scan, dots are formed at every (s−1) dots in the main scan direction by driving each set of nozzle groups at intermittent timing. In the example of FIG. 13, since s = 2, dots are formed every other dot. The driving timing of each nozzle group is controlled so that dots are formed at different positions in the main scanning direction. That is, as shown in FIG. 13, the nozzles of the first nozzle group (nozzle numbers 8, 6, 4, 2) and the nozzles of the second nozzle group (nozzle numbers 7, 5, 3, 1) The recording position is shifted by one dot pitch in the main scanning direction. Then, such main scanning is performed a plurality of times, and the driving timing of each nozzle group is shifted each time, thereby completing the formation of all dots on the raster.

  Also in the overlap method, the nozzle pitch k is set to an integer of 2 or more, similarly to the interlace method. However, the number N of nozzles and the nozzle pitch k do not have a relatively prime relationship. Instead, the value N / s obtained by dividing the number N of nozzles by the number of scan repetitions N and the nozzle pitch k have a relatively prime relationship. Selected as an integer. The sub-scan feed amount L is set to a constant value given by N / (sDk).

  In the overlap method, dots on each raster are not recorded by the same nozzle, but are recorded by using a plurality of nozzles. Therefore, even when the characteristics (pitch, ejection characteristics, etc.) of the nozzles vary, it is possible to prevent the effects of the characteristics of a specific nozzle from affecting the entirety of one raster, thereby improving the image quality. .

  As described above, various dot recording methods have been proposed to date. However, in reality, the quality of image quality also depends on the manufacturing error of the dot recording device. Therefore, the preferred dot recording method may be different for individual dot recording devices manufactured according to the same design. However, conventionally, it has been difficult to adopt a preferable dot recording method suitable for such individual dot recording apparatuses.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems in the related art, and has as its object to provide a technique capable of adopting a preferable dot recording method suitable for each dot recording apparatus.

  In order to solve at least a part of the problems described above, an apparatus of the present invention is a dot recording apparatus that records dots on a surface of a print medium using a dot recording head, and forms dots on the print medium. A dot forming element array in which a plurality of dot forming elements are arranged, a main scanning driving unit that performs main scanning by at least relatively driving the dot recording head and the print medium, and during the main scanning. A head driving unit for driving at least a part of the plurality of dot forming elements to form dots, and each time the main scanning is completed, the dot recording head and the printing medium are at least relatively driven to perform sub-scanning. And a control unit for controlling each of the units. The control unit includes a recording mode storage unit that stores a plurality of dot recording modes that define operations during the main scanning and the sub-scanning for recording dots; and a preferable dot recording mode from among the plurality of dot recording modes. Mode designation information setting means in which mode designation information for designating a mode is set, means for executing dot recording in accordance with a dot recording mode designated by the mode designation information, and initial setting of the dot recording apparatus are registered. Initial setting registration means. The plurality of dot recording modes are classified into a plurality of recording mode groups according to a combination of a recording resolution and a recording speed. The mode designation information designates one dot recording mode for each recording mode group. Further, in the initial setting of the dot recording apparatus, one of the plurality of recording mode groups is selected.

  In such a dot recording apparatus, for each dot recording apparatus, a preferred dot recording mode is selected from a plurality of dot recording modes stored in the recording mode storage means, and mode designation information indicating the preferred dot recording mode is selected. Can be set in the mode designation information setting means. Therefore, a preferable dot recording mode suitable for each dot recording device can be adopted. In the above-described dot recording apparatus, one of the plurality of recording mode groups is selected in the initial setting of the dot recording apparatus. Therefore, when the user does not change the initial setting, the recording mode selected in the initial setting is not changed. A preferred dot recording operation can be performed according to the preferred dot recording mode of the group.

  Note that the initial setting registration unit registers respective initial settings for each surface material of the print medium, and one recording mode group is selected in the initial settings for each surface material of the print medium. At the same time, an initial setting relating to one predetermined type of surface material may be registered as an initial setting of the dot recording apparatus.

  This makes it possible to use a preferable dot recording mode according to the surface material of the print medium in the initial setting state.

  Further, among the plurality of printing mode groups, the plurality of printing mode groups relating to at least one printing resolution may include more dot printing modes as the printing speed is lower.

  Normally, when the recording speed is relatively low, even when recording is performed at the same recording resolution, the difference in image quality between the dot recording modes tends to be considerably large. In the above-described dot recording apparatus, for at least one recording resolution, as the recording speed is slower, more dot recording modes are prepared. Therefore, especially when the recording speed is relatively slow, higher image quality can be obtained. The effect is that it is easy to achieve.

  The present invention includes other aspects as described below. A first aspect is a method of recording dots on the surface of a print medium using a dot recording head having a dot forming element array in which a plurality of dot forming elements for forming dots are arranged, wherein (a) A step of preparing in advance a plurality of dot recording modes for defining operations during main scanning and sub-scanning for recording dots; and (b) specifying a preferred dot recording mode from the plurality of dot recording modes. Selecting a preferred dot recording mode according to preset mode designation information, and executing dot recording according to the preferred dot recording.The plurality of dot recording modes include recording resolution and recording. The recording mode group is classified into a plurality of recording mode groups according to the combination with the speed. And specifies one dot record mode, in the initial setting of the dot recording device, wherein one of a plurality of recording modes group is characterized in that it is selected.

  FIG. 1 is a block diagram showing a configuration of a color image processing system as an embodiment of the present invention. This color image processing system has a scanner 12, a personal computer 90, and a color printer 22. The personal computer 90 has a color display 21. The scanner 12 reads color image data from a color original, and supplies the computer 90 with original color image data ORG including three color components of R, G, and B.

  The computer 90 includes a CPU, RAM, ROM, and the like (not shown), and an application program 95 operates under a predetermined operating system. A video driver 91 and a printer driver 96 are incorporated in the operating system, and the final color image data FNL is output from the application program 95 via these drivers. An application program 95 for retouching an image reads an image from a scanner, performs a predetermined process on the image, and displays the image on a CRT display 93 via a video driver 91. When the application program 95 issues a print command, the printer driver 96 of the computer 90 receives the image information from the application program 95, and receives the image information from the application program 95 as a signal that can be printed by the printer 22 (here, a binary signal for each color of CMYK). Signal). In the example shown in FIG. 1, inside the printer driver 96, a rasterizer 97 that converts color image data handled by the application program 95 into image data in dot units and a printer 22 for image data in dot units are provided. A color correction module 98 that performs color correction according to the ink color CMY to be used and the characteristics of the color development, a color correction table CT that is referred to by the color correction module 98, and ink information in dot units based on the color-corrected image information. A halftone module 99 for generating so-called halftone image information expressing density in a certain area depending on the presence or absence, a mode designation information writing module 110 for writing mode designation information to be described later in a memory in the color printer 22, And a printing condition registration unit 300.

  The printing condition registration unit 300 stores initial settings (to be described later) regarding printing conditions of the printer and various printing conditions selected by the user. A user interface screen for changing various printing conditions of the printer is also displayed on the screen of the computer 90 by the printing condition registration unit 300.

  FIG. 2 is a schematic configuration diagram of the printer 22. As shown in the drawing, the printer 22 includes a mechanism for transporting a sheet P by a paper feed motor 23, a mechanism for reciprocating a carriage 31 in the axial direction of a platen 26 by a carriage motor 24, and a print head mounted on the carriage 31. And a control circuit 40 that controls the ejection of ink and the formation of dots by driving the paper feed motor 23, the carriage motor 24, the print head 28, and the exchange of signals with the operation panel 32. I have.

  On the carriage 31 of the printer 22, a cartridge 71 for black ink and a cartridge 72 for color ink containing three color inks of cyan, magenta and yellow can be mounted. A total of four ink discharge heads 61 to 64 are formed on the print head 28 below the carriage 31, and at the bottom of the carriage 31, an introduction pipe 65 (for introducing ink from the ink tank to each color head). (See FIG. 3). When the black ink cartridge 71 and the color ink cartridge 72 are mounted on the carriage 31 from above, an inlet tube is inserted into a connection hole provided in each cartridge, and ink from the ink cartridge to the ejection heads 61 to 64 is inserted. Supply becomes possible.

  A mechanism for ejecting ink will be briefly described. As shown in FIG. 3, when the ink cartridges 71 and 72 are mounted on the carriage 31, the ink in the ink cartridge is sucked out through the introduction pipe 65 by utilizing the capillary phenomenon, and is provided below the carriage 31. The print heads 28 are guided to the respective color heads 61 to 64 of the print head 28. When the ink cartridge is first mounted, the operation of sucking the ink into the heads 61 to 64 of the respective colors by a dedicated pump is performed. In this embodiment, a pump for suction and a cap for covering the print head 28 at the time of suction are provided. The illustration and description of such a configuration are omitted.

  As shown in FIG. 3, the heads 61 to 64 of each color are provided with 32 nozzles n for each color, and each of the heads 61 to 64 is one of the electrostrictive elements, and is a piezoelectric element having excellent responsiveness. The element PE is arranged. FIG. 4 shows the structure of the piezo element PE and the nozzle n in detail. As shown in the drawing, the piezo element PE is installed at a position in contact with an ink passage 80 that guides ink to the nozzle n. As is well known, the piezo element PE is an element in which the crystal structure is distorted by the application of a voltage and converts the electric-mechanical energy very quickly. In the present embodiment, by applying a voltage having a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE expands by the voltage application time as shown in the lower part of FIG. One side wall 80 is deformed. As a result, the volume of the ink passage 80 contracts in accordance with the expansion of the piezo element PE, and the ink corresponding to this contraction becomes particles Ip and is discharged from the tip of the nozzle n at a high speed. Printing is performed by the permeation of the ink particles Ip into the paper P mounted on the platen 26.

  In the printer 22 having the above-described hardware configuration, the carriage 31 is reciprocated by the carriage motor 24 while the paper P is being conveyed by rotating the platen 26 and other rollers by the paper feed motor 23, and simultaneously, each color of the print head 28 is The piezo elements PE of the heads 61 to 64 are driven to discharge the respective color inks, and a multicolor image is formed on the paper P. The specific arrangement of the nozzles in the heads 61 to 64 for each color will be further described later.

  The mechanism for transporting the paper P includes a gear train (not shown) for transmitting the rotation of the paper feed motor 23 not only to the platen 26 but also to a paper transport roller (not shown). A mechanism for reciprocating the carriage 31 includes an endless drive belt 36 stretched between a carriage shaft 24 and a slide shaft 34 laid parallel to the axis of the platen 26 and slidably holding the carriage 31. And a position detection sensor 39 for detecting the origin position of the carriage 31.

  The control circuit 40 includes a programmable ROM (PROM) 42 as a rewritable nonvolatile memory in addition to a CPU and a main memory (ROM and RAMU) not shown. The PROM 42 stores dot recording mode information including a plurality of dot recording mode parameters. Here, the “dot recording mode” means a dot recording method defined by the number N of nozzles actually used in each nozzle array, the sub-scan feed amount L, and the like. In this specification, “recording method” and “recording mode” are used with almost the same meaning. Specific examples of the dot recording mode and their parameters will be described later. The PROM 42 also stores mode designation information for designating a preferred mode from a plurality of dot recording modes.

  As will be described later, the dot recording modes are classified into a plurality of recording mode groups according to a combination of a recording resolution and a recording speed, and each recording mode group includes at least one dot recording mode. Then, the mode in which the highest quality image can be recorded is selected as a preferable dot recording mode for each recording mode group. By the way, the image quality of an image recorded in each dot recording mode depends on the arrangement characteristics of nozzle arrays in the print head 28 (actual positions of individual nozzles). For example, there may be two nozzles in the nozzle array that are displaced away from (or closer to) each other from their respective design positions. When such two nozzles record two adjacent rasters, a streak-like image degradation part called "banding" occurs between these two rasters. On the other hand, the arrangement of nozzle numbers for recording adjacent raster lines is determined according to the dot recording mode (particularly, the sub-scan feed amount). Therefore, the preferred dot recording mode depends on the characteristics of the print head 28 mounted on the printer (the actual positions of the individual nozzles). As described above, since the dot recording mode designated by the mode designation information is determined according to the characteristics of the print head 28, the mode designation information can be considered as an identifier indicating the type of the print head 28. Therefore, in this specification, the mode designation information is also referred to as “head ID” or “mode ID”.

  The dot recording mode information is read from the PROM 42 by the printer driver 96 when the printer driver 96 (FIG. 1) is installed when the computer 90 is started. That is, the printer driver 96 reads from the PROM 42 the dot recording mode information for the preferred dot recording mode specified by the mode specification information. The processing in the rasterizer 97 and the halftone module 99 and the main scanning and sub-scanning operations are executed according to the dot recording mode information.

  The PROM 42 may be any rewritable nonvolatile memory, and various nonvolatile memories such as an EEPROM and a flash memory can be used. Although the mode designation information is preferably stored in a rewritable nonvolatile memory, the dot recording mode information may be stored in a non-rewritable ROM. Further, the plurality of dot recording mode information may be stored in another storage unit instead of the PROM 42, or may be registered in the printer driver 96.

  FIG. 5 is an explanatory diagram showing the arrangement of the inkjet nozzles in the ink ejection heads 61 to 64. The first head 61 is provided with a nozzle array that ejects black ink. The second to fourth heads 62 to 64 are also provided with nozzle arrays for ejecting cyan, magenta, and yellow inks, respectively. The positions of these four sets of nozzle arrays in the sub-scanning direction coincide with each other.

  The four nozzle arrays each include a plurality (for example, 32 or 48) of nozzles n arranged in a staggered manner at a constant nozzle pitch k along the sub-scanning direction. The plurality of nozzles n included in each nozzle array need not be arranged in a staggered manner, and may be arranged on a straight line. However, the arrangement in a staggered manner as shown in FIG. 5A has the advantage that the nozzle pitch k can be easily set small in manufacturing.

  FIG. 5B shows an arrangement of a plurality of dots formed by one nozzle array. In this embodiment, regardless of whether the arrangement of the ink nozzles is staggered or linear, the plurality of dots formed by one nozzle array are arranged in a substantially straight line along the sub-scanning direction. A drive signal is supplied to the piezo element PE (FIG. 4). For example, consider the case where the nozzles are arranged in a zigzag pattern as shown in FIG. 5A and the head 61 is scanned in the right direction in the figure to form dots. At this time, a driving signal is given to the preceding nozzle groups 100, 102... At a timing earlier by d / v [sec] than to the following nozzle groups 101, 103. Here, d [inch] is the pitch between the two nozzle groups in the head 61 (see FIG. 5A), and v [inch / sec] is the scanning speed of the head 61. As a result, a plurality of dots formed by one nozzle array are arranged on a straight line in the sub-scanning direction. As will be described later, not all of the plurality of nozzles provided in each of the heads 61 to 64 are always used. Depending on the dot recording method, only some of the nozzles are used. In some cases.

  FIG. 6 is a functional block diagram of a configuration related to drive control according to the dot recording mode. The functional block diagram includes a mode ID memory 202, a print mode setting unit 204, a print mode table 206, a drive unit control unit 208, a main scan drive unit 210, a sub scan drive unit 212, a print head drive The section 214, the raster data storage section 216, the print head 28, and the printing paper P are shown.

  The recording mode table 206 stores a plurality of dot recording mode information. In the print mode table 206, among various parameters included in each dot print mode information, a print resolution, a mode group, a mode ID, the number of used nozzles N, and a sub-scan amount L are shown. I have. In addition, each dot recording mode information includes various other parameters for defining main scanning and sub-scanning operations, but these are not shown in FIG.

  In the example of FIG. 6, the plurality of dot recording modes stored in the recording mode table 206 are classified into four mode groups M1 to M4 according to the combination of the recording resolution and the recording speed. The first mode group M1 is a “360 dpi fast” group. Further, the second mode group M2 is a “360 dpi clean (and slow)” group, the third mode group M3 is a “720 dpi fast” group, and the fourth mode group M4 is a “720 dpi clean (and slow)”. Group. The contents of the recording mode table 206 will be further described later.

  The mode ID memory 202 stores a mode ID (mode designation information) for designating a preferable dot recording mode for each mode group. The print mode setting unit 204 sends a main scan to the drive unit control unit 208 and the raster data storage unit 216 according to the print data given from the computer 90 and the mode ID (mode designation information) given from the mode ID memory 202. A parameter defining the sub-scanning operation is supplied. The print data is the same as the final color image data FNL in FIG. The header part (not shown) of the print data includes data designating one of the mode groups M1 to M4 used for printing. The recording mode setting unit 204 determines a dot recording mode to be used for executing printing from the designation of the mode group and the mode ID supplied from the mode ID memory 202.

  The print mode setting unit 204 supplies the scan parameters including the number N of nozzles used and the sub-scan feed amount L in the dot print mode determined in this way to the drive unit control unit 208 and the raster data storage unit 216. Since the number N of used nozzles and the sub-scan feed amount L may be changed for each scan, scanning parameters including these are supplied to the units 208 and 216 before each scan.

  The raster data storage unit 216 stores print data in a buffer memory (not shown) according to scanning parameters including the number of used nozzles N and the sub-scanning amount L. On the other hand, the driving unit control unit 208 controls the main scanning driving unit 210, the sub-scanning driving unit 212, and the print head driving unit 214 according to parameters including the number N of used nozzles and the sub-scanning amount L.

  The mode ID memory 202 and the recording mode table 206 are provided in one PROM 42 shown in FIG. The recording mode setting unit 204, the driving unit control unit 208, and the raster data storage unit 216 are provided in the control circuit 40 shown in FIG. The main scanning drive unit 210 is realized by a feed mechanism of the carriage 31 including the carriage motor 24 shown in FIG. 2, and the sub-scanning drive unit 212 is realized by a paper feed mechanism including the paper feed motor 23. Further, the print head driving unit 214 is realized by a circuit including the piezo element PE of each nozzle.

  FIG. 7 is an explanatory diagram showing parameters that define the dot recording method. FIG. 7A shows an example of sub-scan feed when four nozzles are used, and FIG. 7B shows parameters of the dot recording method. In FIG. 7A, solid circles including numbers indicate the positions in the sub-scanning direction of the four nozzles after each sub-scan feed. Numbers 0 to 3 in the circles indicate nozzle numbers. The positions of the four nozzles are sent in the sub-scanning direction each time one main scan is completed. However, actually, the feed in the sub-scanning direction is realized by moving the paper by the paper feed motor 23 (FIG. 1).

  As shown at the left end of FIG. 7A, in this example, the sub-scan feed amount L is a constant value of 2 dots. Therefore, each time the sub-scan feed is performed, the positions of the four nozzles are shifted by two dots in the sub-scan direction. FIG. 7B shows various parameters related to the dot recording method. The parameters of the dot recording method include the nozzle pitch k [dot], the number of used nozzles N [number], the number of scan repetitions s, the effective nozzle number Neff [number], and the sub-scan feed amount L [dot]. include.

  In the example of FIG. 7, the nozzle pitch k is 3 dots, and the number N of used nozzles is 4. The number of used nozzles N is the number of nozzles actually used among a plurality of mounted nozzles. The number of scan repetitions s means that dots are formed intermittently every (s-1) dots in one main scan. Therefore, the number of scan repetitions s is also equal to the number of nozzles used to record all the dots on one raster. In the case of FIG. 7, the number of scan repetitions s is 2. Note that a dot recording method in which the number of scan repetitions s is 2 or more is called an “overlap method”.

  The effective nozzle number Neff is a value obtained by dividing the used nozzle number N by the number of scan repetitions s. This effective nozzle number Neff can be considered to indicate the net number of rasters that can be printed in one main scan.

  The table of FIG. 7B shows, for each sub-scan feed, the sub-scan feed amount L, the cumulative value ΔL, and the nozzle offset F after each sub-scan feed. Here, the offset F refers to the periodic position of the first nozzle in which the sub-scan feed is not performed (the position every four dots in FIG. 7) as the reference position of the offset 0, and This value indicates how many dots the nozzle position is apart from the reference position in the sub-scanning direction. For example, as shown in FIG. 7A, the nozzle position moves in the sub-scanning direction by the sub-scanning feed amount L (2 dots) by the first sub-scanning feed. On the other hand, the nozzle pitch k is 3 dots. Therefore, the offset F of the nozzle after the first sub-scan feed is 2 (see FIG. 7A). Similarly, the nozzle position after the second sub-scan feed has moved by ΔL = 4 dots from the initial position, and its offset F is 1. The nozzle position after the third sub-scan feed has moved by ΔL = 6 dots from the initial position, and its offset F is zero. Since the nozzle offset F returns to 0 by the three sub-scan feeds, the three sub-scans are regarded as one small cycle, and by repeating this small cycle, all the dots on the raster in the effective recording range are recorded. be able to.

  FIG. 8 is an explanatory diagram showing the scanning parameters in the three dot recording methods having substantially the same recording speed, and shows three dot recordings included in the fourth mode group M4 (720 dpi fine (and slow) mode group). An example of the method is shown. The scanning parameters of the first dot recording method shown in FIG. 8A are such that the nozzle pitch k is 6 dots, the number of used nozzles N is 48, the number of scan repetitions s is 2, and the effective nozzle number Neff is 24. Six different values (20, 27, 22, 28, 21, 26) are used for the sub-scan feed amount L [dot]. The scanning parameters of the second dot recording method shown in FIG. 8B are the same as those of the first dot recording method except for the sub-scan feed amount L. The scanning parameters of the third dot recording method shown in FIG. 8C are as follows. The nozzle pitch k is 6 dots, the number of used nozzles N is 47, the number of scan repetitions s is 2, and the effective nozzle number Neff is 23.5. . Two different values (21, 26) are used for the sub-scan feed amount L [dot].

  The number N of nozzles used in the first and second dot recording methods is 48, whereas the number N of nozzles used in the third dot recording method is 47. However, in these three dot recording methods, the difference in the number N of used nozzles is about 10% or less. Since the actual printing speed (printing speed) is almost proportional to the effective number of nozzles Neff (= N / s), it can be said that the printing speeds of the three dot printing methods shown in FIG. Thus, in this specification, "the recording speeds are substantially equal" means that the difference between the effective nozzle numbers Neff is about 10% or less.

  FIG. 9 is an explanatory diagram showing the contents of the recording mode table 206 and the mode ID memory 202. The plurality of dot recording modes stored in the recording mode table 206 are classified into four mode groups M1 to M4. The first and third mode groups M1 and M3 each include only one recording mode, while the second mode group M2 includes two recording modes and the fourth mode group M4 includes three recording modes. Includes mode. A plurality of printing modes in the same mode group have substantially the same printing speed (that is, the effective nozzle number N / s). For example, the effective nozzle numbers Nd1 / s, Nd2 / s, and Nd3 / s of the three printing modes of the fourth mode group M4 are substantially equal to each other. In the example of FIG. 8, Nd1 / s = Nd2 / s = 24 and Nd3 / s = 23.5.

  The “clean” mode groups M2 and M4 are configured in an overlap type dot recording mode in which the number of scan repetitions s is 2, for example. On the other hand, the “fast” mode groups M1 and M3 are configured in a dot recording mode in which the number of scan repetitions s is 1, for example. Note that the scan repetition s can take a decimal value. In particular, a dot recording mode in which the number of scan repetitions s is larger than 1 and smaller than 2 is called “partial overlap mode”. As the dot recording mode of the “fast” mode groups M1 and M3, it is also possible to adopt a dot recording mode of a partial overlap system. For example, if the number of used nozzles N is 48 and the sub-scan feed amount L is a fixed value of 41 dots, the effective nozzle number Neff is 41 and the number of scan repetitions s is about 1.17 (= 48/41). It will be a lap method. In the partial overlap method, the sub-scan feed amount L can be configured by a combination of a plurality of different values.

  One mode group is composed of dot recording modes having the same recording resolution and printing speeds substantially equal to each other. The image quality of an image recorded in each dot recording mode depends on the array characteristics of the nozzle array in the print head 28 ( Actual position of the individual nozzles). For example, in some cases, one of the three dot recording modes in the fourth mode group M4 shown in FIG. 8 can achieve higher image quality than the other two dot recording modes. Therefore, for each mode group, a preferable dot recording mode for obtaining higher image quality is determined in accordance with the arrangement characteristics of the nozzle array, and its mode ID is registered in the mode ID memory 202. Utilizing the preferred dot recording mode for No. 20, it is possible to perform finer printing.

  As can be easily understood from FIG. 9A, in this embodiment, for each recording resolution, more dot recording modes are prepared as the recording speed is lower. Generally, when the recording speed is relatively slow, the difference in image quality between the dot recording modes tends to be considerably large. Therefore, as in the present embodiment, even if the recording resolution is the same, if the recording speed is slow, it is possible to improve the image quality by selecting a preferable one from among more dot recording modes. Has the advantage that it is easier. Conversely, when the recording speed is high, the difference in image quality between the dot recording modes is not so large, so it is sufficient to prepare a relatively small number of recording modes. Note that in the example of FIG. 9, the “fast” mode groups M1 and M3 are each configured with one recording mode, but each may include a plurality of recording modes.

  The mode ID memory 202 stores four mode IDs for designating preferable recording modes in the four mode groups M1 to M4. That is, a preferable dot recording mode can be independently set for each of the four mode groups M1 to M4. Therefore, in each printer, it is possible to easily set a preferable dot recording mode for each mode group (that is, for each combination of recording resolution and recording speed). This effect is particularly remarkable when all the mode groups each include a plurality of recording modes.

  In the above embodiment, for each of the two recording resolutions of 360 dpi and 720 dpi, the more the recording speed is, the more dot recording modes are prepared. However, for at least one recording resolution, the lower the recording speed, the more dot recording modes need to be prepared, and for a plurality of mode groups having other recording resolutions, the same number of dot recording modes are prepared. May be.

  In the above description, it is assumed that the recording resolutions in the main scanning direction and the sub-scanning direction are the same. However, depending on the printer, a recording mode in which the recording resolutions in the main scanning direction and the sub-scanning direction are different can be used. There are cases. In such a case, recording modes having the same combination of recording resolutions in the main scanning direction and the sub-scanning direction are referred to as “recording resolutions are the same”, and recording modes different in any one are referred to as “recording resolutions are different”. Call. For example, the recording mode in which the recording resolution in the main scanning direction is 720 dpi and the recording resolution in the sub-scanning direction is 360 dpi is different from the recording mode in which both the recording resolution in the main scanning direction and the recording resolution in the sub-scanning direction are 720 dpi. Different and therefore fall into different mode groups.

  By the way, as shown in FIG. 9, in the initial setting of the printing conditions of the printer, the mode group M1 is selected. Therefore, unless the user changes the printing conditions, printing is performed according to the recording mode of the “fast” mode group M1 at 360 dpi. Such an initial setting is suitable when high-speed printing is mainly expected for this printer. On the other hand, when high-quality printing is mainly expected for this printer, the mode group M4 that is "clean" at 720 dpi is suitable as an initial setting. As will be understood, the mode group selected in the initial setting of the printer is determined not for each individual printer but for each printer model. On the other hand, it is preferable that the mode ID indicating a preferable recording mode in each mode group is determined for each printer as described above.

  FIG. 10 is an explanatory diagram showing a case where a mode group is selected according to the type of printing paper in the initial setting of printing conditions. In this specification, the “type of printing paper” means the type of surface material of the printing paper. The classification of the mode group, the value of the mode ID, the number of used nozzles N, and the sub-scanning amount L in FIG. 10 are the same as those in FIG. In FIG. 10, the initial settings are registered for three types of printing paper, namely, “plain paper”, “hooper fine paper”, and “photo print paper”. That is, for "plain paper", the "fast" mode group M1 at 360 dpi is selected as the initial setting. For "super fine paper" and "photo print paper", a "clean" mode group M4 at 720 dpi is selected as an initial setting. In addition, the initial setting of “plain paper” is used as the initial setting of the entire printer.

  FIG. 11 is an explanatory diagram showing an initial setting screen for printing conditions for “photo print paper”. That is, here, the recommended settings (initial settings) when the user selects “photo print paper” are shown. When the user selects “photo print paper”, it is understood that the “clean” mode group is selected as the recommended setting (initial setting). Although more detailed printing conditions such as the recording resolution are not displayed on this screen, as shown in FIG. 10, the "clean" mode group M4 of 720 dpi is selected in the initial setting of "photo print paper". In the initial setting of the printer, “plain paper” is selected as the paper type on the screen of FIG. 11, and the “fast” mode group is selected in the recommended setting (initial setting).

  The user can arbitrarily change the printing conditions by pressing a “detailed setting” button in the mode setting substantially at the center of FIG. For example, in the example of FIG. 10, the “clean” mode group M2 of 360 dpi is not selected as an initial setting for any print paper, but this mode group M2 is selected according to the details of the user's detailed settings. May be done. However, the user can only selectively use any one of the four mode groups M1 to M4. Regarding the mode groups M2 and M4 including a plurality of recording modes, recording modes other than the recording mode specified by the mode ID Cannot be selected. By doing so, it is possible to prevent the user from mistakenly selecting an undesirable recording mode.

  As described above, in the initial setting for each type of printing paper, if a preferable mode group is selected in advance, printing is performed using a preferable recording mode suitable for each type of printing paper in the initial setting state. Can be performed.

  The present invention is not limited to the above-described examples and embodiments, but can be implemented in various modes without departing from the gist of the invention, and for example, the following modifications are possible.

(1) In each of the embodiments described above, the dot recording method for one color has been described. However, by applying the above-described dot recording method for each color, color printing using a plurality of color inks can be realized. .

(2) The present invention is applicable not only to color printing but also to monochrome printing. Further, the present invention can be applied to printing in which one pixel is expressed by a plurality of dots to express multiple gradations. Further, the present invention can be applied to a drum scan printer. In a drum scan printer, the drum rotation direction is the main scanning direction, and the carriage traveling direction is the sub scanning direction. Further, the present invention can be applied not only to an ink jet printer but also to a dot recording apparatus that generally performs recording on the surface of a print medium using a recording head having a plurality of dot forming element arrays. Here, "dot forming element" means a component for forming dots, such as an ink nozzle in an ink jet printer.

(3) In the above embodiment, a part of the configuration realized by hardware may be replaced with software, and conversely, a part of the configuration realized by software may be replaced with hardware. Is also good. For example, the function of the control circuit 40 (FIG. 2) of the color printer 22 may be executed by the computer 90. In this case, a computer program such as the printer driver 96 realizes the same function as the control in the control circuit 40.

  A computer program for realizing such a function is provided in a form recorded on a computer-readable recording medium such as a floppy disk or a CD-ROM. The computer system 90 reads the computer program from the recording medium and transfers it to an internal storage device or an external storage device. Alternatively, a computer program may be supplied from the program supply device to the computer system 90 via a communication path. When implementing the functions of the computer program, the computer program stored in the internal storage device is executed by the microprocessor of the computer system 90. Further, the computer system 90 may directly execute a computer program recorded on a recording medium.

  In this specification, the computer system 90 is a concept including a hardware device and an operation system, and means a hardware device that operates under the control of the operation system. The computer program causes such a computer system 90 to realize the functions of the respective units described above. Some of the functions described above may be realized by an operation system instead of the application program.

  In the present invention, the “computer-readable recording medium” is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but may be an internal storage device in a computer such as various RAMs and ROMs, An external storage device such as a hard disk fixed to the computer is also included.

FIG. 1 is a block diagram illustrating a schematic configuration of an image processing system according to the present invention. FIG. 1 is a schematic configuration diagram illustrating a configuration of a color printer as an example of an image output apparatus. FIG. 2 is an explanatory diagram illustrating the structure of a print head 28. FIG. 3 is an explanatory diagram illustrating the principle of ink ejection. FIG. 6 is an explanatory diagram showing an arrangement of inkjet nozzles in the ink ejection heads 61 to 64. FIG. 3 is a functional block diagram of a configuration related to drive control according to a dot recording mode. FIG. 9 is an explanatory diagram showing nozzle numbers for recording each effective raster in the second dot recording method of k = 4. FIG. 4 is an explanatory diagram showing scanning parameters in four dot recording methods having substantially the same recording speed. FIG. 3 is an explanatory diagram showing the contents of a recording mode table and a mode ID memory. FIG. 4 is an explanatory diagram illustrating a recording mode group selected in an initial setting for each type of printing paper. FIG. 4 is an explanatory diagram showing an initial setting screen for photo print paper. FIG. 3 is an explanatory diagram showing an example of a conventional interlace recording method. Explanatory drawing showing an example of a conventional overlap recording method.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 12 ... Scanner 20 ... Image output device 21 ... Color display 22 ... Color printer 23 ... Paper feed motor 24 ... Carriage motor 26 ... Platen 28 ... Print head 31 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... Pulley 39 ... Position detection sensor 40 ... Control circuit 42 ... PROM
Reference numerals 61 to 64: Ink ejection head 65: Introducing tubes 71, 72: Ink cartridge 80: Ink passage 90: Computer 91: Video driver 93: CRT display 95: Application program 96: Printer driver 97: Rasterizer 98: Color correction module 99 halftone module 100-103 nozzle group 110 mode designation information writing module 120 image sensor 122 mode setting section 202 mode ID memory (mode designation information setting means)
204: recording mode setting unit 208: drive unit control unit 206: recording mode table (recording mode storage means)
210: main scanning drive unit 212: sub-scanning drive unit 214: print head drive unit 216: raster data storage unit 300: printing condition registration unit (initial setting registration unit)

Claims (3)

In a dot recording apparatus that records dots on the surface of a print medium using a dot recording head,
A dot forming element array in which a plurality of dot forming elements for forming dots on the print medium are arranged,
Main scanning driving means for performing main scanning by at least relatively driving the dot recording head and the printing medium,
Head driving means for driving at least a part of the plurality of dot forming elements to form dots during the main scanning,
A sub-scanning driving unit that performs sub-scanning by driving at least the dot recording head and the print medium at least each time the main scanning ends,
Control means for controlling each of the means,
The control means,
Recording mode storage means for storing a plurality of dot recording modes for defining operations during the main scanning and sub-scanning for recording dots;
Mode designation information setting means in which mode designation information for designating a preferred dot recording mode from among the plurality of dot recording modes is set,
Means for performing dot recording according to the dot recording mode specified by the mode specification information,
Initial setting registration means in which initial settings of the dot recording device are registered,
With
The plurality of dot recording modes are classified into a plurality of recording mode groups according to a combination of a recording resolution and a recording speed,
The mode designation information designates one dot recording mode for each recording mode group,
The dot recording apparatus according to claim 1, wherein one of the plurality of recording mode groups is selected in an initial setting of the dot recording apparatus. The dot recording apparatus according to claim 1,
In the initial setting registration unit, each initial setting is registered for each surface material of the printing medium, and one recording mode group is selected in each initial setting for each surface material of the printing medium, A dot recording device, wherein initial settings relating to a predetermined type of surface material are registered as initial settings of the dot recording device. The dot recording apparatus according to claim 1, wherein
A dot recording apparatus, wherein the plurality of recording mode groups relating to at least one recording resolution among the plurality of recording mode groups include more dot recording modes as the recording speed is lower.

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