JP3849702B2 - Dot recording device - Google Patents

Description

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

  As a recording apparatus that performs recording while the recording head scans in the main scanning direction and the sub-scanning direction, there are a serial scan printer, a drum scan printer, and the like. As one of techniques for improving image quality in this type of printer, particularly an ink jet printer, an “interlace method” disclosed in US Pat. No. 4,198,642, Japanese Patent Application Laid-Open No. 53-2040, and the like. There is a technology called.

  FIG. 12 is an explanatory diagram illustrating an example of an interlace method. In this specification, the following parameters are used as parameters for defining the recording method.

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

  The number N of nozzles 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 (dot pitch w) are in the recording head. In the example of FIG. 12, k = 2. The number of scan repetitions s [times] is a number indicating how many main scans 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 by one main scan, s = 1. As will be described later, when s is 2 or more, dots are intermittently formed 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 recording head. The sub-scan feed amount L [dot] or [inch] indicates the distance moved by one sub-scan. The dot pitch w [inch] is the dot pitch in the recorded image. In general, w = 1 / (D · k) and k = 1 / (D · w) are established.

  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 number on the left side indicates the nozzle number, and the number on the right side indicates the printing order (how many times the main scanning is performed). ).

  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 interval between the center points of 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 that are relatively prime to each other. The sub-scan feed amount L is set to a constant value given by N / (D · k).

  This interlace method has an advantage that variations in nozzle pitch, ink ejection characteristics, and the like can be dispersed on a recorded image. Therefore, even if there are variations in the nozzle pitch and ejection characteristics, it is possible to alleviate these effects and improve the image quality.

  As another technique aiming at image quality improvement in a color inkjet printer, there is a technique called “overlap method” or “multi-scan method” disclosed in Japanese Patent Laid-Open No. 3-207665, Japanese Patent Publication No. 4-19030, and the like. .

  FIG. 13 is an explanatory diagram showing an example of the overlap method. In this overlap method, eight nozzles are classified into two sets of nozzle groups. The first group of nozzles is composed of four nozzles having an even number of nozzle numbers (the number on the left side in the circle), and the second group of nozzles is composed of four nozzles having an odd number of nozzles. It consists of a nozzle. In one main scan, dots are formed 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 drive timing of each group of nozzle groups 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) are The recording position is shifted by one dot pitch in the main scanning direction. Such main scanning is performed a plurality of times, and the drive 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, as in the interlace method. However, the number of nozzles N and the nozzle pitch k are not relatively prime. Instead, the value N / s obtained by dividing the number of nozzles N by the number of scan repetitions s and the nozzle pitch k are relatively prime. It is chosen as an integer. The sub-scan feed amount L is set to a constant value given by N / (s · D · k).

  In this overlap method, dots on each raster are not recorded by the same nozzle, but are recorded using a plurality of nozzles. Therefore, even when there are variations in nozzle characteristics (pitch, ejection characteristics, etc.), it is possible to prevent the influence of specific nozzle characteristics from affecting one entire raster, and as a result, image quality can be improved. .

  As described above, various dot recording methods have been proposed so far. However, in reality, the quality of the image depends on the manufacturing error of the dot recording apparatus. Therefore, the preferred dot recording method may be different for individual dot recording apparatuses 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.

  The present invention has been made to solve the above-described problems in the prior art, and an object of the present invention is 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 above-described problems, an apparatus of the present invention is 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 drive means for performing main scanning by relatively driving the dot recording head and the printing medium at least;
Head driving means for driving at least a part of the plurality of dot forming elements during the main scanning to form dots;
Sub-scanning driving means for performing sub-scanning by driving the dot recording head and the printing medium at least relatively each time the main scanning is completed;
Control means for controlling each means,
The control means includes
A recording mode storage means for storing a plurality of dot recording modes for defining operations at the time of 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 the plurality of dot recording modes is set;
Means for performing dot recording according to the dot recording mode designated by the mode designation information;
With
The plurality of dot recording modes are classified into recording mode groups having recording speeds different from each other with respect to at least one recording resolution, and the recording speed of the plurality of recording mode groups with the at least one recording resolution is low. One recording mode group includes more dot recording modes than the second recording mode group having a high recording speed.

In such a dot recording apparatus, a preferable dot recording mode capable of achieving high image quality is selected from a plurality of dot recording modes stored in the recording mode storage means for each dot recording apparatus, and this preferable dot recording is performed. Mode designation information indicating the mode can be set in the mode designation information setting means. Therefore, a preferable dot recording method suitable for each dot recording apparatus can be adopted. By the way, when the recording speed is relatively low, even when recording is performed at the same recording resolution, the difference in image quality depending on the dot recording mode tends to be considerably large. In the above dot recording apparatus, for at least one recording resolution, the first recording mode group having a low recording speed includes more dot recording modes than the second recording mode group having a high recording speed. When the speed is low, there is an effect that it is easy to achieve higher image quality.

The mode designation information setting means may be set with mode designation data for designating one dot recording mode for each recording mode group having a different combination of recording resolution and recording speed.

In this way, since a preferable dot recording mode can be independently designated for each of a plurality of recording mode groups, high image quality can be easily achieved for each recording mode group.

  The present invention includes other aspects as follows. A first aspect is a method for recording dots on the surface of a print medium using a dot recording head having a dot formation element array in which a plurality of dot formation elements for forming dots are arranged. A step of preparing a plurality of dot recording modes prescribing operations during main scanning and sub-scanning for recording dots; and (b) designating a preferred dot recording mode from among the plurality of dot recording modes. Selecting a preferred dot recording mode in accordance with mode setting information set in advance, and executing dot recording in accordance with the preferred dot recording mode, wherein the plurality of dot recording modes include a recording resolution and a recording. It is classified into a plurality of recording mode groups according to the combination with the speed, and the mode designation information is recorded in each recording mode group 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 the configuration of a color image processing system as an embodiment of the present invention. This color image processing system includes a scanner 12, a personal computer 90, and a color printer 22. The personal computer 90 includes a color display 21. The scanner 12 reads color image data from a color original, and supplies original color image data ORG including three color components of R, G, and B to the computer 90.

  The computer 90 includes a CPU, RAM, ROM, etc. (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 that performs image retouching or the like reads an image from the scanner and performs a predetermined process on the image, and displays the image on the CRT display 93 via the 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 this is a signal that can be printed by the printer 22 (here, binarized for each color of CMYK). Signal). In the example shown in FIG. 1, the printer driver 96 includes a rasterizer 97 that converts color image data handled by the application program 95 into image data in units of dots, and a printer 22 for the image data in units of dots. The color correction module 98 that performs color correction according to the ink colors CMY to be used and the characteristics of color development, the color correction table CT that the color correction module 98 refers to, and the image information after color correction, the ink in dot units A halftone module 99 for generating so-called halftone image information expressing density in a certain area depending on presence or absence, a mode designation information writing module 110 for writing mode designation information, which will be described later, into 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 figure, the printer 22 includes a mechanism for transporting paper 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 exchange of signals with the paper feed motor 23, the carriage motor 24, the print head 28, and the operation panel 32. Yes.

  The carriage 31 of the printer 22 can be mounted with a black ink cartridge 71 and a color ink cartridge 72 containing three colors of cyan, magenta, and yellow. A total of four ink ejection heads 61 to 64 are formed on the print head 28 below the carriage 31. An introduction pipe 65 (for introducing ink from the ink tank to the heads for the respective colors is provided at the bottom of the carriage 31. (See FIG. 3). When the black ink cartridge 71 and the color ink cartridge 72 are mounted on the carriage 31 from above, an introduction tube is inserted into a connection hole provided in each cartridge, and ink from each 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 via the introduction pipe 65 using the capillary phenomenon, and is provided at the lower part of the carriage 31. The print head 28 is guided to the respective color heads 61 to 64. When the ink cartridge is first mounted, an operation of sucking ink to the respective color heads 61 to 64 is performed by a dedicated pump. In this embodiment, a pump for suction, a cap that covers the print head 28 at the time of suction. The illustration and description of such a configuration is 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 nozzle is one of electrostrictive elements and has excellent responsiveness. 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 the ink passage 80 that guides ink to the nozzle n. As is well known, the piezo element PE is an element that transforms electro-mechanical energy at a very high speed because the crystal structure is distorted by application of a voltage. 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 extends for the voltage application time as shown in the lower part of FIG. One side wall of 80 is deformed. As a result, the volume of the ink passage 80 contracts according to the expansion of the piezo element PE, and the ink corresponding to the contraction becomes particles Ip and is ejected from the tip of the nozzle n at high speed. Printing is performed by the ink particles Ip soaking into the paper P mounted on the platen 26.

  In the printer 22 having the hardware configuration described above, the carriage 31 is reciprocated by the carriage motor 24 while the platen 26 and other rollers are rotated by the paper feed motor 23 to convey the paper P, and at the same time, each color of the print head 28. The piezo elements PE of the heads 61 to 64 are driven to discharge each color ink and form a multicolor image on the paper P. The specific arrangement of the nozzles in each color head 61 to 64 will be described later.

  The mechanism for transporting the paper P includes a gear train (not shown) that transmits the rotation of the paper feed motor 23 not only to the platen 26 but also to a paper transport roller (not shown). Further, the mechanism for reciprocating the carriage 31 has an endless drive belt 36 stretched between the carriage motor 24 and a slide shaft 34 that is mounted in parallel with the axis of the platen 26 and slidably holds 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. Examples of specific dot recording modes and their parameters will be described later. The PROM 42 further stores mode designation information for designating a preferable mode from among 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 the combination of recording resolution and recording speed, and each recording mode group includes at least one dot recording mode. For each recording mode group, the mode that can record the image with the highest image quality is selected as the preferred dot recording mode. By the way, the image quality of an image recorded in each dot recording mode depends on the arrangement characteristics of the nozzle array in the print head 28 (actual positions of individual nozzles). For example, there may be two nozzles in the nozzle array that are displaced in a direction away from (or approaching) each design position. When such two nozzles record two adjacent rasters, a streak-like image quality deterioration portion called “banding” occurs between the two rasters. On the other hand, the arrangement of nozzle numbers for recording adjacent rasters is determined according to the dot recording mode (particularly the sub-scan feed amount). Therefore, the preferred dot recording mode depends on the characteristics (actual position of each nozzle) of the print head 28 mounted on the printer. Thus, since the dot recording mode specified by the mode specifying information is determined according to the characteristics of the print head 28, the mode specifying information can also 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 activated. That is, the printer driver 96 reads the dot recording mode information for the preferable dot recording mode designated by the mode designation information from the PROM 42. Processing in the rasterizer 97 and the halftone module 99 and 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. The mode designation information is preferably stored in a rewritable nonvolatile memory, but the dot recording mode information may be stored in a ROM that cannot be rewritten. The plurality of dot recording mode information may be stored not in the PROM 42 but in other storage means, and may be registered in the printer driver 96.

  FIG. 5 is an explanatory diagram showing the arrangement of 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 sets of 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. Note that the plurality of nozzles n included in each nozzle array need not be arranged in a staggered manner, and may be arranged in a straight line. However, as shown in FIG. 5A, when arranged in a zigzag pattern, there is an advantage that the nozzle pitch k can be easily set small.

  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, a 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, when the nozzle array is arranged in a staggered manner as shown in FIG. 5A, consider a case where the head 61 is scanned in the right direction in the figure to form dots. At this time, the preceding nozzle groups 100, 102... Are given drive signals at a timing earlier by d / v [seconds] than the 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 / second] is the scanning speed of the head 61. As a result, the plurality of dots formed by one nozzle array are arranged on a straight line along the sub-scanning direction. As will be described later, the total number of the plurality of nozzles provided in each of the heads 61 to 64 is not always used, and only some of the nozzles are used depending on the dot recording method. In some cases.

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

  The recording mode table 206 stores a plurality of dot recording mode information. In the recording mode table 206, among various parameters included in each dot recording mode information, the recording resolution, the mode group, the mode ID, the number N of used nozzles, and the sub-scanning amount L are shown. Yes. In addition, each dot recording mode information includes various parameters for defining the main scanning operation and the sub-scanning operation, which 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 combinations of recording resolution and recording speed. The first mode group M1 is a “fast at 360 dpi” group. Also, 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 “720 dpi clean (and slow)”. It is a 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 recording mode setting unit 204 performs main scanning on the drive unit control unit 208 and the raster data storage unit 216 in accordance with the print data given from the computer 90 and the mode ID (mode designation information) given from the mode ID memory 202. A parameter that defines the operation of the sub-scan is supplied. The print data is the same as the final color image data FNL in FIG. The header portion (not shown) of the print data includes data specifying 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 execution of printing from the designation of the mode group and the mode ID supplied from the mode ID memory 202.

  The recording mode setting unit 204 supplies scanning parameters including the number N of used nozzles and the sub-scan feed amount L in the dot recording mode determined in this way to the driving unit control unit 208 and the raster data storage unit 216. Since the number of used nozzles N and the sub-scan feed amount L may be changed for each scan, scan 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 the 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 in accordance with parameters including the number of used nozzles N and the sub scanning amount L.

  Note that 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 drive 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 feeding mechanism of the carriage 31 including the carriage motor 24 shown in FIG. 2, and the sub-scanning driving unit 212 is realized by a paper feeding mechanism including the paper feeding motor 23. Further, the print head driving unit 214 is realized by a circuit including the piezoelectric element PE of each nozzle.

  FIG. 7 is an explanatory diagram showing parameters defining the dot recording method. FIG. 7A shows an example of sub-scan feed when four nozzles are used, and FIG. 7B shows the parameters of the dot recording method. In FIG. 7A, solid circles including numerals 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 every time one main scanning is completed. In practice, however, feeding 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. Accordingly, every time the sub-scan feed is performed, the positions of the four nozzles are shifted by 2 dots in the sub-scanning direction. FIG. 7B shows various parameters relating to this dot recording method. The parameters of the dot recording method include nozzle pitch k [dots], number of used nozzles N [pieces], number of scan repetitions s, number of effective nozzles Neff [pieces], and sub-scan feed amount L [dots]. include.

  In the example of FIG. 7, the nozzle pitch k is 3 dots, and the number of used nozzles N is 4. The number N of used nozzles is the number of nozzles actually used among the plurality of mounted nozzles. The number of scan repetitions s means that dots are intermittently formed every (s-1) dots in one main scan. Therefore, the scan repetition number 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 scan repetition number s is 2. A dot recording method in which the number of scan repetitions s is 2 or more is referred to as an “overlap method”.

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

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

  FIG. 8 is an explanatory diagram showing scanning parameters in three dot recording methods having substantially the same recording speed, and the three dot recordings included in the fourth mode group M4 (the 720 dpi clean (and slow) mode group). An example of the scheme is shown. The scanning parameters of the first dot recording method shown in FIG. 8A are that the nozzle pitch k is 6 dots, the number of used nozzles N is 48, the scan repetition number s is 2, and the effective nozzle number Neff is 24. Also, 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 that the nozzle pitch k is 6 dots, the number of used nozzles N is 47, the scan repetition number 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].

  In the first and second dot recording methods, the number of used nozzles N is 48, while in the third dot recording method, the number of used nozzles N 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 recording speed (printing speed) is substantially proportional to the effective nozzle number Neff (= N / s), it can be said that the recording speeds of the three dot recording systems shown in FIG. Thus, in this specification, “recording speeds are substantially equal” means that the difference in the number of effective nozzles 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. Each of the first and third mode groups M1 and M3 includes only one recording mode, but the second mode group M2 includes two recording modes, and the fourth mode group M4 includes three recording modes. Includes modes. A plurality of recording modes in the same mode group have substantially the same recording speed (that is, effective nozzle number N / s). For example, the effective nozzle numbers Nd1 / s, Nd2 / s, and Nd3 / s in the three recording 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 with an overlap type dot recording mode in which the scan repetition number s is 2, for example. On the other hand, the “fast” mode groups M1 and M3 are configured with, for example, a dot recording mode in which the scan repetition number s is 1. 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 method”. As the dot recording mode of the “fast” mode group M1, M3, it is possible to adopt a dot recording mode of a partial overlap method. For example, if the number of used nozzles N is 48 and the sub-scan feed amount L is a constant value of 41 dots, the effective number of nozzles Neff is 41 and the scan repetition number s is about 1.17 (= 48/41). It becomes a lap method. Even 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, but the image quality of an image recorded in each dot recording mode depends on the arrangement characteristics of the nozzle array in the print head 28 ( The actual position of the individual nozzles). For example, one dot recording mode among the three dot recording modes of the fourth mode group M4 shown in FIG. 8 may be able to achieve higher image quality than the other two dot recording modes. Therefore, for each mode group, a preferred dot recording mode capable of obtaining higher image quality is determined in accordance with the arrangement characteristics of the nozzle array, and the mode ID is registered in the mode ID memory 202. It is possible to print more beautifully by using the preferred dot recording mode for No. 20.

  As can be easily understood from FIG. 9A, in this embodiment, for each recording resolution, as the recording speed is lower, more dot recording modes are prepared. In general, when the recording speed is relatively low, the difference in image quality depending on the dot recording mode tends to be considerably large. Therefore, as in this embodiment, even if the recording resolution is the same, it is possible to improve the image quality if a preferable one can be selected from a larger number of dot recording modes when the recording speed is low. Has the advantage of being easier. On the contrary, 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. In the example of FIG. 9, each of the “fast” mode groups M1 and M3 is configured by 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 set independently for each of the four mode groups M1 to M4. Therefore, 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) in each printer. 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, more dot recording modes are prepared as the recording speed is lower. However, for at least one recording resolution, it is sufficient that more dot recording modes are prepared as the recording speed is lower, and the same number of dot recording modes are prepared for a plurality of mode groups having other recording resolutions. It 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 is a case. 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 “the same recording resolution”, and different recording modes in either one are referred to as “the 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, and the recording mode in which both the recording resolution in the main scanning direction and the sub-scanning direction are 720 dpi is “recording resolution”. Different and therefore fall into different mode groups.

  Incidentally, as shown in FIG. 9, the mode group M1 is selected in the initial setting of the printing conditions of the printer. Therefore, if the user does not change the printing conditions, printing is performed at 360 dpi according to the recording mode of the “fast” mode group M1. Such 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, a mode group M4 “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 for each printer model, not for each individual printer. On the other hand, the mode ID indicating the preferred recording mode in each mode group is preferably 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, “type of printing paper” means the type of surface material of the printing paper. The mode group classification, mode ID value, number of used nozzles N, and sub-scanning amount L in FIG. 10 are the same as those in FIG. In FIG. 10, initial settings are registered for three types of printing paper, “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. In addition, for “super fine paper” and “photo print paper”, a mode group M4 of “beautiful” at 720 dpi is selected as an initial setting. 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, a recommended setting (initial setting) when the user selects “photo print paper” is shown. When the user selects “photo print paper”, it can be seen that the “clean” mode group is selected as the recommended setting (initial setting). In this screen, more detailed printing conditions such as recording resolution are not displayed, but as shown in FIG. 10, a “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 in the screen of FIG. 11, and the “fast” mode group is selected as the recommended setting (initial setting).

  The user can arbitrarily change the printing conditions by pressing the “detailed setting” button in the mode setting 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 the initial setting for any printing paper, but is selected by the mode group M2 according to the details of the user's detailed settings. May be. However, the user can only selectively use one of the four mode groups M1 to M4, and the recording mode other than the recording mode specified by the mode ID is associated with the mode groups M2 and M4 including a plurality of recording modes. Cannot be selected. In this way, it is possible to prevent the user from accidentally selecting an undesirable recording mode.

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

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

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

(2) The present invention can be applied not only to color printing but also to monochrome printing. Further, the present invention can be applied to printing that expresses multiple gradations by expressing one pixel with a plurality of dots. It can also be applied to a drum scan printer. In the drum scan printer, the drum rotation direction is the main scanning direction, and the carriage traveling direction is the sub-scanning direction. The present invention can be applied not only to an ink jet printer but also to a dot recording apparatus that performs recording on the surface of a printing 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. Also good. For example, the function of the control circuit 40 (FIG. 2) of the color printer 22 can be executed by the computer 90. In this case, a computer program such as the printer driver 96 implements 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 a computer program from the recording medium and transfers it to an internal storage device or an external storage device. Or you may make it supply a computer program to the computer system 90 from a program supply apparatus via a communication path. When realizing the function 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 the computer program recorded on the 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 the computer system 90 to realize the functions of the above-described units. Note that some of the functions described above may be realized by an operation system instead of an 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 an internal storage device in a computer such as various RAMs and ROMs, An external storage device fixed to a computer such as a hard disk is also included.

1 is a block diagram showing a schematic configuration of an image processing system of the present invention. FIG. 2 is a schematic configuration diagram illustrating a configuration of a color printer 22 as an example of an image output device 20. 3 is an explanatory diagram illustrating the structure of a print head 28. FIG. Explanatory drawing explaining the principle of the discharge of an ink. FIG. 6 is an explanatory diagram showing an arrangement of inkjet nozzles in the ink ejection heads 61 to 64. The functional block diagram of the structure relevant to the drive control according to dot recording mode. Explanatory drawing which shows the nozzle number which records each effective raster in the 2nd dot recording system of k = 4. Explanatory drawing which shows the scanning parameter in four dot recording systems with substantially equal recording speed. Explanatory drawing which shows the content of the recording mode table and mode ID memory. FIG. 3 is an explanatory diagram showing a recording mode group selected by initial setting for each type of printing paper. Explanatory drawing which shows the initial setting screen with respect to photo print paper. Explanatory drawing which shows an example of the conventional interlace recording system. Explanatory drawing which shows an example of the conventional overlap recording system.

Explanation of symbols

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
61-64 ... Ink ejection head 65 ... Introducing pipe 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 ... print condition registration unit (initial setting registration unit)

Claims (2)

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 drive means for performing main scanning by relatively driving the dot recording head and the printing medium at least;
Head driving means for driving at least a part of the plurality of dot forming elements during the main scanning to form dots;
Sub-scanning driving means for performing sub-scanning by driving the dot recording head and the printing medium at least relatively each time the main scanning is completed;
Control means for controlling each means,
The control means includes
A recording mode storage means for storing a plurality of dot recording modes for defining operations at the time of 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 the plurality of dot recording modes is set;
Means for performing dot recording according to the dot recording mode designated by the mode designation information;
With
The plurality of dot recording modes are classified into recording mode groups having recording speeds different from each other with respect to at least one recording resolution, and the recording speed of the plurality of recording mode groups with the at least one recording resolution is low. The dot recording apparatus according to claim 1, wherein the one recording mode group includes more dot recording modes than the second recording mode group having a high recording speed. The dot recording apparatus according to claim 1,
A dot recording apparatus in which mode specifying data for specifying one dot recording mode is set for each recording mode group having a different combination of recording resolution and recording speed in the mode specifying information setting means.

Images