JP2005205636A - Inkjet recorder and method of inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder capable of making deterioration in an image such as stripe-like irregularity or moire-type irregularity to be inconspicuous in a result recorded by means of a full-multi type recording head. <P>SOLUTION: A plurality of nozzles arranged on the full-multi type recording head are divided into blocks by a unit of the plural number of nozzles. In the case where driving in a time sharing manner wherein driving timings of recording elements are shifted by the unit of the block is carried out in an ejection timing for ejecting ink from the nozzles, a plurality of driving patterns having different driving sequences of the blocks are prepared and the nozzles in each block are driven by using the respective driving pattern by each ejection timing, thereby differentiating the driving sequences of the blocks. As a result, it is possible to prevent the occurrence of a special dot arrangement or a regular pattern in a conveyance direction of a recording medium. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus and a recording method, and more specifically, recording using a full multi-type long recording head (hereinafter also referred to as a “full line recording head”) having a length equal to or greater than the paper width of a recording medium. The present invention relates to an ink jet recording apparatus and a recording method for forming an image on the entire recording medium by relative movement between a head and the recording medium.

  Recording devices used in printers, copiers, etc., or printing devices used as output devices such as composite electronic devices including computers and word processors, and workstations, print images on recording media such as paper and plastic thin plates based on the recorded information. (Including characters, symbols, etc.) is recorded. Such a recording apparatus can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a recording method.

  The ink jet type performs dot recording by causing ink to land on a recording medium such as paper from a plurality of nozzles provided in the recording head, and has the advantage of low noise because it does not contact the recording medium. . In addition, high resolution and high speed recording are possible by increasing the density of the nozzles. Furthermore, since special processing such as development and fixing is not required for recording media such as plain paper, it is relatively inexpensive and expensive. A high-quality image can be provided, and its use is becoming widespread in recent years. In particular, an on-demand type ink jet recording apparatus can be easily colored, and the apparatus itself can be reduced in size and simplified. In addition, with the spread of colorization as described above, higher image quality and higher speed are increasingly required.

  In addition, against the background of recent technological advances in nozzle integration, it has become possible to manufacture recording heads that are higher in density and longer. A recording head that has nozzles arranged at a high density and is manufactured in a long length is generally called a full multi-type recording head. Since this has a length equal to or greater than the paper width of the recording medium, the recording head is arranged so that the longitudinal direction of the head is in the paper width direction of the recording medium, and a predetermined recording width is recorded by one ejection operation, and thereafter The next recording area is recorded by relatively moving the recording medium and the recording head. In this way, an image is formed on the entire recording medium.

  By the way, there is a serial type that performs recording by scanning a recording head in the paper width direction of a recording medium as a recording apparatus that is widely used. Both the full multi type and the serial type perform recording by ejecting ink droplets from a plurality of nozzles arranged in the recording head. However, since the serial type recording head has a small number of arranged nozzles, the ejection amount and landing Products with uniform positions can be manufactured at a relatively high yield rate. On the other hand, a full multi-type printhead will have more nozzles than a serial-type printhead, and all these nozzles should be manufactured with a uniform discharge rate and landing position accuracy without any defects. Is very difficult. Even if it can be manufactured, the yield rate is much lower than the serial type. Therefore, in an inkjet recording apparatus using a full multi-type recording head, in order to correct non-uniform discharge amount and landing error of nozzles, the landing position shift is measured in advance at the manufacturing stage, and correction according to the shift amount is performed. Do. By performing an actual recording operation in a state corrected by so-called head shading, landing errors are made inconspicuous.

  However, various methods have been devised in the past for the method of correcting by head shading. However, it is difficult to say that it is sufficient to perform high-quality recording in one scan. Further, with repeated discharge operations, the state of the nozzle also changes from the initial state of shipment, but the landing error for this cannot be overtaken by the above-described head shading. Therefore, when recording a high-quality image such as a photographic image, it is difficult to say that the image quality is sufficient.

  On the other hand, even in a serial type recording apparatus, the state of the nozzle changes due to repeated use, and the landing position of the dots may shift. Therefore, when forming a high-quality image such as a photographic image, a multi-pass recording method is used in which the recording head scans the same area of the recording medium multiple times and records one line with different nozzles. In general, the dot landing error is made inconspicuous. However, in the full multi type, such a multi-pass printing cannot be performed due to the structure, and the nozzle for recording each pixel is determined in advance in both the paper width direction and the scanning direction. It tends to be more noticeable than the record.

  Further, when all the nozzles in the recording head are driven simultaneously, the maximum power consumption increases. Since it is not preferable to provide a large power supply corresponding to this in terms of volume and cost, usually at the same time so that the power consumption does not exceed the power that can be supplied by the power supply at one discharge timing. Limit the nozzles to be driven. Specifically, time-division drive control is performed in which the nozzle row is divided into a plurality of blocks each having several nozzles, and the discharge timing is gradually shifted in units of blocks. Conventional time-division drive control is performed as follows.

  FIG. 1 is a diagram showing a full multi-type ink jet recording apparatus.

  FIG. 4 is a schematic diagram showing a nozzle surface of a full multi-type recording head.

  FIG. 6 is a diagram showing nozzle groups that are driven simultaneously when the nozzle row is divided into a plurality of units of blocks. FIG. 8 shows a case where the number of drive blocks is limited to four. In this way, the number of nozzles that are driven simultaneously is limited to a predetermined number, and the nozzle drive timing is shifted in units of blocks.

  FIG. 24 is a timing chart showing an example of the driving order when the head is divided into four blocks (nozzle groups) for driving. According to this timing chart, when the nozzle group of each block is driven to record an image with 50% duty (in which dots are driven every other pixel row), a recording result as shown in FIG. 25 is obtained.

  As can be seen from FIG. 25, since the ink droplets ejected from the respective nozzles have different heat start timings for each drive block, the ink dot landing positions are displaced. In particular, when printing is performed by one scan (one pass), such a deviation of the landing position continuously occurs in a stable state. When a recorded result having such a regular shift of the landing position due to time-division driving is visually observed, streak-like unevenness or moire-like unevenness is visually recognized as a whole.

  In addition, as shown in the portion indicated by the width L1 in FIG. 25, the dots ejected from both nozzles of the first block in the driving order and the last block in the driving order of the adjacent nozzles have mutual landing positions. A big shift. Further, since the dot deviation until then is constant, a dot pattern similar to the 4-dot portion 1001 driven in the blocks A to D is periodically generated in the scanning direction. It is easy to be recognized as unevenness in the eyes.

  In order to improve this, conventionally, as shown in FIG. 26, the drive order of each block within one cycle (one discharge cycle) in which the first drive block to the last drive block is driven as a whole is shown in FIG. Is changed so that it is different from the same block order (A, B, C, D order) (in order of A, D, B, C in FIG. 26) so that the drive timing time interval between adjacent nozzles is shortened. There has also been proposed a driving order set (see Patent Document 1). In this case, a recording result as shown in FIG. 27 is obtained.

27 shows that the deviation of the landing positions of the ink dots between adjacent nozzles is smaller than that in FIG.
However, since a dot pattern similar to that of the 3-dot portion 1002 that is driven in the order of blocks A, D, B, and C is continuously generated in a stable state, the recording result is visually observed. Fine stripe-like unevenness or moire-like unevenness is visually recognized.

  The present invention has been made in view of the above-described conventional problems, and even when an image is formed by a single scan (one pass) using a long full multi-type recording head, Ink jets that can output high-quality recording results with less noticeable image degradation such as regular deviations in dot landing positions due to time-division driving, and streaky irregularities and moire irregularities due to deviations in dot landing positions that occur in the nozzle state An object is to provide a recording apparatus and an ink jet recording method.

Japanese Unexamined Patent Publication No. 08-207284

  The inkjet recording apparatus of the present invention moves a recording head in which a plurality of small heads in which a plurality of recording elements are arranged in a predetermined direction is alternately arranged relative to the recording medium, and from each of the recording elements for each ejection cycle. In an ink jet recording apparatus that performs recording by ejecting ink onto the recording medium, a recording element driving unit that divides the plurality of recording elements into a plurality of unit blocks and performs time-division driving within the ejection cycle; The recording element driving means comprises block driving order determining means for determining the driving order of the blocks, and the block driving order determining means varies the driving order of the blocks for each ejection cycle. To do.

  In the recording head, it is preferable that the adjacent recording elements are time-division driven so as to be different blocks.

  Further, in the ejection timing, the preceding block in the block to which each of the adjacent recording elements belongs is longer than the maximum block interval time which is the time required from the driving timing of the first driving block to the driving timing of the last driving block. It is preferable that the block drive order determination unit determines the drive order of the blocks so that the time required from the drive of the block to the subsequent block is shortened.

  In the inkjet recording method of the present invention, a recording head in which small heads in which a plurality of recording elements are arranged in a predetermined direction is moved relative to the recording medium, and from each of the recording elements for each ejection cycle. In an ink jet recording method using an ink jet recording apparatus that performs recording by ejecting ink onto the recording medium, the plurality of recording elements are divided into a plurality of unit blocks, and time-division driving is performed within the ejection cycle. A printing element driving step, and a block driving order determination step for determining the driving order of the blocks in the printing element driving step, wherein the block driving order determination step changes the driving order of the blocks for each ejection cycle. It is characterized by making it.

  In this specification, “record” is not only formed when significant information such as characters and figures is formed, but also manifested so that human beings can perceive it visually. Regardless of whether or not the image, pattern, pattern or the like is widely formed on the recording medium, or the medium is processed.

  In addition, “recording medium” means not only paper used in general ink jet recording apparatuses but also materials that can accept ink ejected by the head, such as cloth, plastic film, metal plate, and the like. To do.

  Further, the term “ink” should be interpreted broadly in the same way as the definition of “recording”, and is applied to a recording medium to form images, patterns, patterns, etc., or to process a recording material. Shall be said to be a liquid.

  According to the present invention, since each recording element is driven by changing the drive order of the blocks at each ejection timing, the regularity of dots formed on the recording medium by each recording element in the recording medium conveyance direction Since a recording result in which dots are finely dispersed can be obtained, a specific dot arrangement pattern is regularly generated in the recording medium conveyance direction, which causes moiré-like or stripe-like unevenness in human eyes. The recording result with improved image quality can be provided without being recognized as.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing an outline of an ink jet recording apparatus according to an example for explaining driving of the present invention.
A plurality of recording heads 120 are installed on a recording medium conveying belt (hereinafter referred to as “conveying belt”) 203. The recording medium 201 placed on the recording medium conveyance belt 203 is conveyed directly under the recording head 120 by the rotation of the conveyance belt 203, and ink is ejected from the recording head 120 at this timing to perform recording.

  The recording head 120 is divided for each ink color, and ejects black (BK), cyan (C), magenta (M), and yellow (Y) ink, respectively. In addition, an ink supply tube (not shown) is connected to the recording head, and further, a control signal and the like are sent via a flexible cable (not shown). The recording medium 201 is properly used according to the recording application, such as plain paper, high-quality exclusive paper, OHP sheet, glossy paper, glossy film, postcard, and the like.

  In addition, the recording head seals the ink discharge port surface by capping means (not shown) to prevent clogging due to ink sticking or adhesion of foreign matters such as dust due to evaporation of the ink solvent. To prevent.

  Further, the capping function of the capping means may be used for idle ejection in which ink is ejected to the cap portion away from the ink ejection port in order to eliminate ejection defects and clogging of the ink ejection port with low recording frequency. Then, the pump (not shown) is operated in a capped state, and ink is sucked from the ink discharge port, which is used for discharge recovery of the discharge port that has caused discharge failure. Further, by disposing a blade and a wiping member (not shown) adjacent to the cap portion, it is possible to clean the ink discharge port forming surface of the inkjet head.

FIG. 2 is a schematic exploded view showing a partial structure of the recording head.
The recording head 120 is generally composed of a heater board 23 that is a substrate on which a plurality of heaters 22 for heating ink is formed, and a top plate 24 that is placed on the heater board 23. A plurality of discharge ports 25 are formed in the top plate 24, and a tunnel-like liquid path 26 communicating with the discharge ports 25 is formed behind the discharge ports 25. Each liquid passage 26 is connected to one ink liquid chamber in common behind it, and ink is supplied to the ink liquid chamber via an ink supply port, and this ink is supplied from the ink liquid chamber to each liquid passage. Supplied to 26. The heater board 23 and the top plate 24 are assembled so that the heaters 22 come to positions corresponding to the liquid passages 26 and are in the state shown in FIG.

  Although only four heaters 22 are shown in FIG. 2, the heaters 22 are arranged one by one corresponding to the respective liquid paths 26. When a predetermined drive pulse is supplied to the heater 22 in the assembled state as shown in FIG. 2, the ink on the heater 22 boils to form bubbles, and the ink expands from the discharge port 25 by the volume expansion of the bubbles. Extruded and discharged. The ink jet recording method applicable to the present invention is not limited to the bubble jet (R) method using a heating element (heater) as shown in FIGS. 1 and 2, and for example, continuous ink droplets are used. In the case of the continuous type that ejects and forms particles, the charge control type, the divergence control type, etc., and in the case of the on-demand type that ejects ink droplets as necessary, the orifice is generated by mechanical vibration of the piezoelectric vibration element. It is also possible to apply a pressure control method for ejecting ink droplets from

  FIG. 3 is a block diagram showing an example of the configuration of the control system of the ink jet recording apparatus of this example. In FIG. 3, 31 is an image data input unit, 32 is an operation unit, 33 is a CPU unit for performing various processes, 34 is a storage medium for storing various data, and the storage contents are divided as follows. Reference numeral 34a denotes a portion for storing information relating to the recording medium, and mainly stores information relating to the type of the recording medium. Reference numeral 34b denotes a part for storing information about ink. Reference numeral 34c denotes a part for storing information related to the environment such as temperature and humidity during recording. 34d is a part for storing various control program groups. Furthermore, 35 is a RAM, 36 is an image data processing unit, 37 is a printer unit for outputting an image, and 38 is a bus unit for transferring various data.

  Each part will be described in more detail. The image data input unit 31 inputs multi-value image data from an image input device such as a scanner or a digital camera, or multi-value image data stored in a hard disk of a personal computer. The operation unit 32 includes various keys for instructing various parameter settings and recording start. The CPU 33 controls the entire recording apparatus according to various control programs in the storage medium 34. As the storage medium 34 for storing the control program, ROM, FD, CD-ROM, HD, memory card, magneto-optical disk, or the like is used. Reference numeral 35 denotes a RAM used as a work area for various programs in the storage medium 34, a temporary save area for error processing, and a work area for image processing. The RAM 35 can also copy the various tables in the storage medium 34, change the contents of the tables, and proceed with image processing while referring to the changed tables.

  The image data processing unit 36 quantizes the input multi-value image data into N-value image data for each pixel, and creates an ejection pattern corresponding to the gradation value “K” indicated by each quantized pixel. To do. That is, after the input multi-value image data is subjected to N-value processing, an ejection pattern corresponding to the gradation value “K” is created. For example, when multi-value image data expressed in 8 bits (256 gradations) is input to the image data input unit 31, the image data processing unit 36 sets the gradation value of the output image data to 25 (= 24 + 1) values. Need to convert. Here, the multilevel error diffusion method is used for the K-value processing of the input gradation image data. However, the present invention is not limited to this, and any halftone processing method such as an average density storage method or a dither matrix method may be used. Can do. Further, by repeating the above-described K-value conversion process for all the pixels based on the density information of the image, a binary drive signal for ejection and non-ejection for each pixel with respect to each ink nozzle is formed.

  The printer unit 37 ejects ink based on the ejection pattern created by the image data processing unit 36 to form a dot image on the recording medium. The bus line 38 transmits address signals, data, control signals, and the like in the apparatus.

  In this example, the image data input by the image data input unit 31 is color-separated so as to correspond to the heads of each color, and then the color-separated gray image is binarized by an error diffusion method. The recording data is set for each nozzle of the recording head.

  Details of the drive control method for each nozzle of the recording head in the ink jet recording apparatus having such a configuration will be described below.

FIG. 4 is a schematic diagram illustrating the nozzle surface of the recording head.
The recording head 120 has a nozzle surface in which nozzles 121 are arranged in a line in the longitudinal direction. In the recording apparatus, the nozzle surface is disposed so as to face the recording medium. In the drawing, the longitudinal direction of the recording head is the paper width direction of the recording medium, and the recording medium is conveyed in the direction of the arrow 44. The recording head and the recording medium may be anything as long as they are relatively movable.

FIG. 5 is a diagram illustrating the relationship between each nozzle and the landing dot on the recording medium.
Here, a 50% duty image in which dots are driven every other line is formed. If the pixel is a matrix as shown in the figure (hereinafter referred to as “recording matrix”), the nozzle 1 has dots in (1, a), (1, c), (1, e), (1, g). Type in. That is, the ink dots ejected from the nozzles 1 to 8 are (N, a), (N, c), (N, e), (N, g) (N = 1 to 8) on the recording matrix. It has been driven. Thus, the full multi type recording head has a fixed row for each nozzle.

  Further, as described in the problem, the nozzles arranged in the recording head are divided into a plurality of blocks and driven in a time-sharing manner due to the relationship with the power amount of the power supply. FIG. 6 is a schematic diagram showing the drive block. FIG. 7 is a drive pulse diagram showing how the ejection timing is shifted for each block in a time-sharing manner. If the ejection timing is simply shifted in the order of nozzle arrangement, this will occur, but this will cause the problems described in the section. In addition, although the drive block is divided | segmented into the block A-the block N, in the following description, in order to make an explanation easy to understand, it simplifies to four division of the block A-the block D.

FIG. 8 is a diagram showing nozzle groups driven by the same block when the drive block is limited to four blocks.
As described in the problem, conventionally, since the drive pulse is transmitted by shifting the rising timing of the block A to the block D one pulse at a time (see FIG. 24), the arrangement of dots in the recording result is regularly slanted. It has shifted | deviated (refer FIG. 25). This is because the oblique dot arrangement occurs periodically, which causes the human eye to recognize it as moire-like unevenness. Further, as shown in FIG. 26, when the rise timings of blocks B, C, and D are manipulated so that pulses rise in the order of block A, block D, block B, and block C, the recording results are shown in FIG. However, oblique dot arrangement still occurs periodically, and this is recognized as unevenness.

  Therefore, in this example, when determining the ejection timing for each block, the dot landing positions are finely dispersed using a plurality of drive patterns so that the periodicity in the arrangement of dots to be formed is not noticeable. So that it is not recognized as unevenness in human eyes.

9 to 12 are timing charts showing four types of drive patterns (pattern 1, pattern 2, pattern 3, and pattern 4) when the four drive blocks are divided and driven.
In each pattern, each block of adjacent printing elements (e.g., the time required for driving the last block in the driving order after driving the first block in the ejection timing, i.e., the maximum block interval time) The drive order of each block is set so that the time required for the drive order in the block A and the block B) from the drive of the previous block to the drive of the subsequent block is always shorter. .

  The recording flow with this drive pattern will be described by taking as an example the case of forming an image with 50% duty every other row as shown in FIG.

  First, at the first ejection timing, each nozzle is driven in the order of driving pattern 1 (in the order of block D, block A, block C, and block B) to eject ink. Then, the recording result at timing 1 in FIG. 13 is obtained (see the dot row at the left end in the figure). Next, since recording is performed every other line, ejection is not performed at the second ejection timing. At the third ejection timing, each nozzle is driven in the driving order of pattern 2 instead of pattern 1 (in the order of block B, block D, block A, and block C), and ink is ejected. Then, the recording result at timing 3 in FIG. 13 is obtained (see the second dot row from the left in the figure). Next, since recording is performed every other line, ejection is not performed at the fourth ejection timing. Then, at the fifth ejection timing, each nozzle is driven in the order of driving pattern 3 (in the order of block A, block D, block B, and block C) to eject ink. Then, the recording result at the timing 5 in FIG. 13 is obtained (see the third dot row from the left in the figure). Next, since every other row, no discharge is performed at the sixth discharge timing. Then, at the seventh ejection timing, each nozzle is driven in the order of driving pattern 4 (in the order of block C, block A, block D, and block B) to eject ink. Then, the recording result at the timing 7 in FIG. 13 is obtained (see the fourth dot row from the left in the figure). Thereafter, similarly, the above four types of patterns are used in order for each ejection timing, and ink ejection is repeated.

  As shown in FIG. 13, the landing positions from the nozzles are not regular in the scanning direction of the recording head, and the dots are landed with fine dispersion. Therefore, the human eye does not recognize the stripe-like unevenness or the moire-like unevenness.

(Embodiment 1)
Next, an embodiment of the present invention using a recording head having a configuration as shown in FIG. 14 will be described.
In this recording head, chips (small heads) each having a plurality of nozzle groups 161 to 164 each having a plurality of nozzles are arranged shifted in the nozzle row direction. In the figure, four chips are arranged alternately. Each chip is arranged so that there is 1200 dpi (about 21.2 μm) between the nozzle at the end of the nozzle row arranged in each chip and the nozzle at the end of the adjacent chip. In addition, the nozzle rows in each chip have a two-row configuration, and adjacent nozzles are arranged in a staggered manner with a slight shift in the alignment direction. Therefore, the nozzles are arranged more highly integrated than the recording head shown in FIG.

  Ink droplets ejected from each nozzle are scanned in advance by the print head relative to the recording material for printing, nozzle rows 161A and 163A, nozzle rows 161B and 163B, nozzle rows 162A and 164A, and nozzle row 162B. In addition, the ejection timing of the entire nozzle row is shifted by an amount corresponding to the interval between the four nozzle rows of 164B and 164B, and the ink dots are set to land in the same row on the recording matrix. Next, the correspondence between nozzles and dots will be specifically described with reference to the drawings.

  As shown in FIG. 15, the ink dots ejected from the chip 1 nozzles N + 1 to N + 4 and the chip 2 nozzles N + 5 to N + 8 are (N + m, a), (N + m, c), (N Land in + m, e), (N + m, g), (m = 1-8).

  FIG. 16 is a schematic diagram showing a drive block to which each nozzle corresponds when each nozzle of the chip having the configuration shown in FIG. 14 is divided into four blocks and driven. If attention is paid to the chip 1 nozzles N + 1 to N + 4, the nozzles are divided into blocks A to D in order from the nozzle with the smallest nozzle number. Therefore, the nozzle row 161A is ejected at the timing of the block A and the block C, and the nozzle row 161B is ejected at the timing of the block B and the block D.

  According to such block division, the ejection operation of each nozzle is performed according to the timing charts shown in FIGS. Similar to the first embodiment, by outputting ejection signals according to different drive patterns for each ejection timing, the recording result shown in FIG. 13 can be obtained as in the first embodiment.

  The ejection timing is shifted as a whole corresponding to the interval between the nozzle rows such as the nozzle rows 161A, 161B, 162A, and 162B so that the ink dots land in the same row on the recording matrix. Yes.

  As is apparent from the recording results, the landing positions from the nozzles are not regularly distributed in the scanning direction of the recording head and landed, so that good recording with no streak-like unevenness or moire-like unevenness can be visually observed. Result.

  Furthermore, the present invention can also be implemented by using the drive patterns shown in FIGS. 9 to 12 even in a recording head having the following shape.

  17 to 19 are schematic views showing other examples of long heads. FIG. 17 shows a long head in which nozzles are arranged in two rows, and FIG. 18 shows a chip in which nozzle rows are in one row. 19 shows a long head in which nozzles are alternately arranged, and FIG. 19 shows a long head in which two rows of nozzles are alternately arranged and the overlapping portion between the chips is larger than that in FIG.

  Even with these long heads, the drive patterns shown in FIGS. 9 to 12 can be applied, and the ink is driven by driving the nozzles in a different drive block order for each ejection timing regardless of the arrangement of the nozzles. It is possible to suitably implement the present invention by discharging the water.

  Note that the number of divisions when the nozzles of the recording head are divided into a plurality, the combination pattern of the driving order within one discharge cycle of each divided drive block, and the combination of drive patterns used for each discharge cycle, etc. As for the present invention, the present invention is not limited to that shown in the above-described embodiment, but various parameters such as the number of nozzles, length, number of time-division driving, and driving speed of the recording head used, and a plurality of chips are connected. In the case of configuring a head, it can be set as appropriate according to variables such as the number and length of chips.

Hereinafter, the present invention will be described more specifically by way of examples.
(Example)
FIG. 20 is a schematic diagram showing a full multi-type recording head used in an example which is a premise for explaining the driving used in this embodiment.
The recording head 241 has a single nozzle row, and 640 nozzles are arranged in a row at 1200 dpi intervals (about 21.2 μm). Here, arrows 243 and 244 indicate the relative movement direction of the recording head and the recording medium, and the recording head scans in the direction of arrow 243 and the recording medium relatively moves in the direction of 244 to perform recording.

  Also in this recording head, each nozzle is divided into four drive blocks, block A to block D, as shown in FIG. Therefore, one block consists of 160 nozzles. Then, as described in the embodiment, the four types of drive patterns shown in FIGS. 9 to 12 are selected at each discharge timing, and the discharge operation of each block is executed according to the selected timing chart.

  The configuration of the ink jet recording apparatus in this example is the same as that shown in FIG. In this example, the following ink and recording medium were used, actual recording was performed under the following driving conditions, and the recording result was verified.

  The ink used is a commercially available ink jet printer BJF870 (manufactured by Canon Inc.), and the amount of ink droplets ejected from the recording head is 5.0 ± 0.5 pl. As a recording medium, photo glossy paper dedicated to inkjet (Pro Photo Paper, PR-101: manufactured by Canon Inc.) is used.

  The drive condition of the recording head was a drive speed and an ink droplet ejection drive frequency of 8 kHz. As for the amount of ink to be printed, images with 5.0 pl dots being 100% duty, 75% duty, 50% duty, 25% duty, and photographic images were prepared.

  Further, the recording method described above is used after head shading correction is performed to measure the discharge amount variation, twisting, and non-discharge in advance for each nozzle of the head and reduce the nozzle variation.

  When printing a recording matrix with a 1200 dpi pixel square at an ejection frequency of 8 KHz, each ejection reference timing is every 125 μsec. Since each chip is driven by being divided into four blocks as described above, the ejection timing of each block is set to be shifted by about 31 μsec (= 125 μsec / 4 blocks).

  When the prepared image is printed in one scan (one pass) under the setting conditions as described above, image quality degradation such as streak-like unevenness and moire-like unevenness is not observed at each recording duty. I was able to get a good recording result. Similarly, with a photographic image, a satisfactory recording result with no image quality deterioration was obtained.

(Example)
In this embodiment, a description will be given of a case in which a recording head having chips arranged alternately is used.

FIG. 21 is a diagram showing a long recording head used in this embodiment.
Four chips each having 128 nozzles arranged at an interval of 600 dpi (about 42.5 μm) are used, and a head configuration with a total of 512 nozzles is used.

FIG. 22 is a diagram showing the block division of each nozzle.
As described above, the nozzles in each chip are divided into four drive blocks for every four nozzles, and the ink droplets are ejected by driving the blocks 1 to 4 in an arbitrary order.
The drive order of these four blocks is set to drive in different drive block orders according to the drive patterns 1 to 4 of FIGS. 9 to 12 selected for each ejection timing, as in the first embodiment.

Further, in accordance with the arrangement interval for each nozzle row in the scanning direction, that is, an amount corresponding to the interval between the four nozzle rows of nozzle rows 281A and 283A, nozzle rows 281B and 283B, nozzle rows 282A and 284A, and nozzle rows 282B and 284B. Thus, it is set so that the ink dots land on the same row (the same row on the print matrix) when printing is performed by shifting the discharge timing of the entire nozzle row.
This makes it possible to form lines with high print quality when line patterns such as ruled lines are recorded.

  The apparatus configuration of the ink jet recording apparatus is the same as the above example except for the recording head, and the same amount of ink is ejected and the driving conditions are the same as in the above example. In each recording duty, it was possible to obtain satisfactory recording results with no image quality deterioration such as streak-like unevenness and moire-like unevenness.

  Similarly, when another photographic tone image data was recorded, it was possible to obtain a satisfactory recording result with no image quality degradation.

(Comparative example)
For comparison with the first embodiment, the recording head, the ink jet recording apparatus, and various setting conditions such as the head driving conditions were the same as in the first embodiment, and only the nozzle driving timing chart was changed to the conventional example for recording. .

  FIG. 23 is a timing chart showing the drive order of each block used in this example, which is set to repeat the same drive order in each ejection cycle. In this example, instead of selecting a timing chart pattern for each ejection timing as in the first embodiment, recording is always performed according to the timing chart of FIG.

  As for the recording results, image quality deterioration such as fine stripe-like unevenness and moire-like unevenness was observed particularly in the duty portion of 75% and 100% having a high recording duty.

  Similarly, when another photographic tone image data was printed, the image quality deteriorated particularly in the portion corresponding to the background.

(Other)
In addition, examples of such an ink jet recording system that can be realized relatively simply and at low cost include, but are not limited to, the following.

  The present invention provides an excellent effect particularly in a recording apparatus using an ink jet recording head that performs recording by forming flying droplets using thermal energy among ink jet recording methods.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface, and as a result, bubbles in the liquid (ink) corresponding to the drive signal can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (straight liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the thermal action A configuration using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the portion is arranged in a bent region, is also included in the present invention.

  In addition, it is preferable to add a recording head ejection recovery means, a preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, heating is performed using a capping unit, a cleaning unit, a pressurizing or suction unit, an electrothermal transducer, a heating element different from this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

1 is a schematic diagram illustrating a configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a diagram schematically illustrating a partial structure of a recording head in the embodiment. 1 is a block diagram illustrating an electrical configuration of an ink jet recording apparatus according to an embodiment. FIG. 4 is a schematic diagram illustrating an arrangement of a plurality of nozzle groups in the full multi-type recording head of the embodiment. FIG. 5 is a schematic diagram illustrating a correspondence relationship between the recording head of FIG. 4 and recording dots. FIG. 5 is a schematic diagram illustrating nozzle groups corresponding to the drive block of the recording head in FIG. 4. It is a figure which shows the timing chart at the time of shifting discharge timing by a block unit by a time division. It is a figure which shows the nozzle group driven by the same block at the time of restricting a drive block to 4 blocks. FIG. 6 is a timing chart for driving pattern 1; FIG. 6 is a diagram showing a timing chart of drive pattern 2; FIG. 5 is a diagram showing a timing chart of drive pattern 3; FIG. 6 is a diagram illustrating a timing chart of a drive pattern 4. It is a figure which shows the recording result driven according to the timing chart shown in FIGS. It is the schematic diagram shown about arrangement | positioning of the several nozzle group of the full multitype recording head in another embodiment of this invention. FIG. 15 is a schematic diagram illustrating a correspondence relationship between the recording head of FIG. 14 and recording dots. FIG. 15 is a schematic diagram illustrating nozzle groups corresponding to the drive block of the recording head in FIG. 14. It is a schematic diagram which shows the other example of a full multitype recording head. It is a schematic diagram which shows the other example of a full multitype recording head. It is a schematic diagram which shows the other example of a full multitype recording head. FIG. 2 is a schematic diagram illustrating an arrangement of a plurality of nozzle groups of a recording head in Embodiment 1. FIG. 6 is a schematic diagram illustrating an arrangement of a plurality of nozzle groups of a recording head in Example 2. FIG. 22 is a schematic diagram illustrating nozzle groups corresponding to the drive block of the recording head in FIG. 21. It is a figure which shows the drive timing chart of the block in a comparative example. It is a figure which shows an example of the drive timing chart of the conventional block. FIG. 25 is a diagram illustrating a recording result when a nozzle is driven in the timing chart illustrated in FIG. 24. It is a figure which shows an example of the drive timing chart of the conventional block. FIG. 27 is a diagram illustrating a recording result when the nozzle is driven in the timing chart illustrated in FIG. 26.

Explanation of symbols

DESCRIPTION OF SYMBOLS 120 Recording head 201 Recording medium 202 Conveyance roller 22 Heater 23 Heater board 24 Top plate 25 Discharge port 26 Liquid path 31 Image data input part 32 Operation part 33 CPU
34 storage medium 35 RAM
36 Image data processing unit 37 Printer unit 38 Bus unit

Claims (7)

A plurality of recording heads in which a plurality of recording elements are arranged in a predetermined direction are moved relative to the recording medium, and ink is applied to the recording medium from each of the recording elements at each ejection cycle. In an inkjet recording apparatus that performs recording by discharging,
Recording element driving means for dividing the plurality of recording elements into a plurality of unit blocks and performing time-division driving within the ejection cycle;
The recording element driving means comprises block driving order determining means for determining the driving order of the blocks,
The ink jet recording apparatus, wherein the block driving order determination unit changes the driving order of the blocks for each ejection cycle.   2. The ink jet recording apparatus according to claim 1, wherein in the recording head, the adjacent recording elements are time-division driven so as to be different blocks.   In the ejection timing, the previous block in the block to which each of the adjacent printing elements belongs is longer than the maximum block interval time that is the time required from the drive timing of the first driven block to the drive timing of the last driven block. 3. The block drive order determination unit determines the drive order of each block so that the time required for driving a subsequent block after driving is shortened. Inkjet recording device.   4. The block driving order determination unit has a plurality of driving order patterns in which the driving order of the blocks is different, and selects the driving order pattern for each ejection timing. An ink jet recording apparatus according to claim 1.   The array length of the recording elements in the recording head is longer than the length in a direction parallel to the array direction of the recording elements in the recordable area of the recording medium. The ink jet recording apparatus described.   The recording element includes an electrothermal converter, generates bubbles in the ink by heat energy from the electrothermal converter, and discharges a predetermined amount of ink as droplets by the generation pressure of the bubbles. An ink jet recording apparatus according to any one of claims 1 to 5. A recording head in which small heads in which a plurality of recording elements are arranged in a predetermined direction are alternately moved is moved relative to the recording medium, and ink is applied to the recording medium from each of the recording elements at each ejection cycle. In an inkjet recording method using an inkjet recording apparatus that performs recording by discharging,
A recording element driving step of dividing the plurality of recording elements into a plurality of unit blocks and performing time-division driving within the ejection cycle;
A block driving order determining step for determining a driving order of the blocks in the recording element driving step,
In the ink jet recording method, the block driving order determination step varies the driving order of the blocks for each ejection cycle.

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