JP2008149611A - Inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to avoid to generate a decrease in density, stripes and unevenness on an image even when an inclination of a recording head caused by static and dynamic factors is generated, in a constitution using an inkjet recording head in which at least two rows of delivering openings for delivering ink with the same color tone are arranged. <P>SOLUTION: Recording of a part (the same column) extending in the direction (sub-scanning direction) intersecting at right angles to the main scanning direction at the same position in the main scanning direction is performed by using the same row of the delivering openings. It is possible thereby to suppress a deterioration of the image such as the decrease in density caused by a dot forming positional shift even when an inclination is generated on a carrying condition of the recording head caused by a fluctuation on manufacturing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a recording method for performing recording using an inkjet recording head.

  2. Description of the Related Art With the spread of information processing equipment such as copying machines, word processors, computers, and communication equipment, as one of output devices for image recording (printing) of these equipment, an ink jet recording apparatus that performs recording by an ink jet method There is. The ink jet recording apparatus has an advantage that an ink jet recording head (hereinafter, also simply referred to as a recording head), which is a recording means, can be easily made compact, and a high-definition image can be recorded at a high speed. Also, it can be printed on plain paper without requiring special processing, so the running cost is low, and because it is a non-impact method, there is little noise, and ink of multiple colors (color, density) is used. By doing so, there is an advantage that it is easy to record a color image.

  In recent years, with the widespread use of inkjet recording apparatuses having these advantages, there has been a demand for higher definition and higher speed of the recording operation. For this reason, the recording head has a large number of ejection openings arranged at high density. Is used. In addition, in an ink jet recording apparatus capable of color recording, a recording head provided with a plurality of ejection opening arrays corresponding to a plurality of ink colors is used.

  As the ink jet recording apparatus, there are a so-called line printer type and a so-called serial printer type, but the latter is mainly used as a relatively small personal use or office use. This is because the main scanning in which ink is ejected in the process of moving the recording head relative to the recording medium in a direction different from the direction in which the ejection ports are arranged, and the recording medium is relatively moved in a direction perpendicular to the main scanning direction. An image is formed by alternately performing sub-scanning. In such an ink jet recording apparatus of the serial printer type, it is possible to cope with high-speed recording by performing bidirectional recording in which a recording operation is performed in the main scanning in the forward direction and the main scanning in the backward direction.

  However, when bidirectional color recording is performed using a recording head in which ejection port arrays for ejecting a plurality of color tones, for example, cyan (C), magenta (M), and yellow (Y) inks are arranged in the main scanning direction, The ejection order of each color ink is different between main scanning and backward main scanning. As a result, the order in which each color ink is applied to the recording medium differs between the forward main scanning and the backward main scanning, and the color development of the secondary colors is not uniform, resulting in band-like unevenness with different colors. Sometimes.

  Therefore, a technique for coping with each color recording heads arranged side by side symmetrically is known. For example, in Patent Document 1, a C ejection port array, an M ejection port array, a Y ejection port array, a Y ejection port array, an M ejection port array, and a C ejection line in the main scanning direction. A configuration is disclosed in which the arrangement order of the colors is left-right symmetric by arranging the discharge port arrays in this order. By using the recording head having such an arrangement, it is possible to perform bidirectional color recording in which the ink application sequence is the same in the forward main scanning and the backward main scanning, thereby making secondary color development uniform. Will be able to.

JP 2001-171119 A

  Incidentally, the ink droplets ejected from the recording head and attached to the recording medium spread on the recording medium to form dots, and an image is recorded as an aggregate of the dots. The area of one dot greatly depends on the size of the ink droplet, that is, the ink discharge amount. Then, in order to realize high-definition and high-quality recording comparable to a silver salt photograph using an inkjet method, the ink ejected from the recording head tends to be as fine as possible.

  As a method for achieving such high-definition recording, a technique for forming an image by combining dots formed by ink droplets of different sizes (inks having different ejection amounts) is known. According to this, it becomes possible to arrange dots of different diameters in the image, and the image portion where the graininess is conspicuous has a relatively small diameter dot, while the “solid” portion has a relatively large diameter dot. By forming it, image recording can be performed. Therefore, while the graininess of the image is reduced, the “solid” portion can be efficiently painted over a large area with a small number of ejections, so that high-quality and high-speed recording is possible.

  By applying the above-described symmetrical arrangement of the ejection port arrays suitable for bidirectional recording to the configuration for obtaining such different ink ejection amounts, it is expected that high-quality recording can be performed at higher speed.

  FIG. 4A is a schematic plan view of an ink jet recording head showing a configuration example thereof. The recording head is configured around a Si substrate 10, and five ink supply ports denoted by reference numerals 131 to 135 are formed in the substrate 10 in parallel in the main scanning direction. Here, the ink supply ports 131 and 135 located on the left and right sides correspond to cyan, the ink supply ports 132 and 134 located inside thereof correspond to magenta, and the ink supply port 133 located in the center corresponds to yellow ink, respectively. For each ink supply port, there are provided a plurality of discharge ports arranged at a predetermined density (600 dpi (dot / inch; reference value)) in the sub-scanning direction, and an ink path communicating with each discharge port. ing. In other words, the color order is symmetric with respect to the recording scanning direction, and ink is applied to the recording medium in the order of cyan, magenta, and yellow in both forward scanning and backward scanning. It has become. In addition, an energy generating element such as an electrothermal conversion element (heater) is formed in a part of the ink path, and a drive signal is supplied through the electrode part 12 formed at the end of the base.

  On both sides of the ink supply ports 131, 132, 134, and 135, the ejection port rows CL 1, ML 1, ML 2, and CL 2 that have a relatively large ink ejection amount and the ejection port row CS 1 that has a relatively small ejection amount, respectively. , MS1, MS2, and CS2. On the other hand, on both sides of the yellow ink supply port 133, a row of discharge ports (YL1 and YL2) having a relatively large ink discharge amount is arranged. Here, the yellow ink has only a discharge port array with a large ink discharge amount. The yellow ink has relatively low visibility compared to cyan ink and magenta ink, and even a large dot has almost no graininess. This is because the effect of making droplets is small without affecting.

  In the relationship between the ejection port arrays having a relatively large ink ejection amount for each color, the ejection ports are arranged with a shift of ½ of the arrangement pitch in the sub-scanning direction, and are set to be 1200 dpi by complementing each other. The recording resolution is realized. The relationship between the ejection port arrays with relatively small ink ejection amounts for cyan and magenta is also the same.

  With the recording head having such a configuration, it is possible to form an image with a recording density of 1200 dpi using large dots and small dots for cyan and magenta, and to form an image with a recording density of 1200 dpi using large dots for yellow. In particular, when printing is performed on plain paper with an emphasis on speed, bi-directional printing can be performed on the same image area using only ejection port arrays with a large ink ejection amount. At this time, since the ejection port arrays for the same color ink are arranged symmetrically, the ink application sequence can be made equal in the forward scan and the backward scan, and the occurrence of uneven color in the secondary color can be prevented. Can do. In addition, an image with less graininess can be formed with high definition while effectively using an ejection port array with a small ink ejection amount.

  However, as a result of investigations by the present inventors, it has been found that performing the symmetrical arrangement regardless of the ink discharge amount may cause problems. The problem will be described below.

  The recording head is positioned with respect to the guide shaft of the recording apparatus via a plurality of members, that is, a carriage and other parts, and main scanning is performed. Therefore, as shown in FIG. 4A, if the respective ejection port arrays are accurately perpendicular to the guide shaft, the ejection port arrays separated from each other (in this case, for example, the ejection port array CL1 for cyan ink). And CL2 and CS1 and CS2) can complement each other. In practice, however, the print head and carriage may have manufacturing variations, so the print head may be slightly tilted and the ejection port array may not be completely perpendicular to the guide shaft. .

  FIG. 4B is an explanatory diagram of this state, in which the recording head is tilted by an angle θ with respect to the extending direction of the guide shaft, that is, the main scanning direction. Due to such an inclination, a deviation of about 11 μm (1/2400 inch) is further generated between the ejection ports included in the ejection port arrays CS1 and CS2 that should have a sub-scanning direction distance of about 21 μm (1/1200 inch). ing.

  FIGS. 5A and 5B are schematic diagrams showing dot formation states corresponding to the cyan ink ejection port arrays in the states of FIGS. 4A and 4B, respectively. 5 (a) and 5 (b), the left-hand part is the 2 in the main scanning direction of relatively large-diameter dots cl1 and cl2 respectively formed by the discharge port arrays CL1 and CL2 having a relatively large discharge amount. The arrangement state at the position is shown. The right portion shows the arrangement state of the relatively small-diameter dots cs1 and cs2 formed by the discharge port arrays CS1 and CS2 having a relatively small discharge amount at two positions in the main scanning direction.

  In FIG. 4A, each discharge port array is mounted completely perpendicular to the guide shaft, so that the discharge port arrays CL1 and CL2 and the discharge ports of CS1 and CS2 that are separated from each other complement each other. Accordingly, as shown in FIG. 5A, dots that are not displaced in the sub-scanning direction can be formed at any position in the main scanning direction.

  However, in FIG. 4B, since the discharge ports of the separate discharge port arrays are displaced by a regular pitch or more, as shown in FIG. 5B, the formed dots are also displaced in the sub-scanning direction. Has occurred.

  Here, if the ejection amount is sufficiently large, as shown in the left part of FIG. 5B, the formed dot diameter is also sufficiently large with respect to the deviation, so that the area factor in the sub-scanning direction (the dot coverage on the recording medium) The change in rate is very small and its influence can be ignored. However, in the ejection port array with a small ink ejection amount, as shown in the right part of FIG. 5B, the formed dots are small and the area factor change rate in the sub-scanning direction is relatively large.

  The area factor change rate described here is determined by the relationship between the ejection port arrangement pitch and the dot diameter, and becomes a problem when the ejection port arrangement pitch is relatively small with respect to these dot diameters. The above is the description when the discharge ports are arranged at a density of 1200 dpi, but the same phenomenon occurs even at other arrangement densities.

  As described above, in the configuration of the recording head shown in FIG. 4B, the density fluctuation in the sub-scanning direction appears greatly when the ejection port array with a small ink ejection amount is used to perform high-definition recording. There may be a problem that streaks in the scanning direction (lateral direction) are easily noticeable. In addition, since the amount of deviation changes depending on the distance in the main scanning direction between the ejection port arrays, there is a case where the influence of density fluctuations becomes relatively larger in the order of yellow, magenta, and cyan, and there is a problem that the overall color balance is lost. .

  The above is a problem caused by static deviation. However, the relative difference in the position of the discharge port array in the main scanning direction is also caused by dynamic factors such as carriage and guide shaft vibration during main scanning. Depending on the situation, the state of FIG. 5A and the state of FIG. 5B may appear repeatedly. That is, when an ejection port array with a small ink ejection amount is used, there is a problem that the influence of density fluctuation that appears depending on the position in the main scanning direction becomes large, and streaks in the sub scanning direction (vertical direction) occur.

  The present invention has been made in view of the above problems. The purpose is to avoid the occurrence of density reduction, streaks, and image unevenness even when the print head is tilted in a configuration using a print head in which at least two rows of ejection openings for ejecting ink of the same color are arranged. Is to be able to do that.

  For this purpose, the present invention scans an ink jet recording head in which at least two rows of ejection openings for ejecting ink of the same color are arranged in a direction different from the direction of the row with respect to the recording medium. An inkjet recording method for performing recording, wherein recording of a portion at the same position in the scanning direction and extending in a direction orthogonal to the scanning direction is performed using the same row of ejection ports. To do.

  In the present invention, recording of a portion (same column) at the same position in the main scanning direction and extending in a direction orthogonal to the main scanning direction (sub scanning direction) is performed using the same ejection port array. . Thereby, the area factor does not change, and even when the mounting state of the recording head is inclined due to manufacturing variations or the like, it is possible to suppress image deterioration such as density reduction due to dot formation position shift.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  In the present specification, the term “image” refers not only to the formation of information such as characters, figures, pictures, and photographs, but also to patterns and patterns that are widely formed on recording media, regardless of significance. It shall be said to be colored throughout. “Recording” refers to the overall operation of forming such an image. Further, the “recording medium” refers to not only general paper used in a recording apparatus but also a wide range of materials that can accept ink, such as cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like. In the following description, it may be referred to as “paper”.

(Basic configuration of recording apparatus and recording head)
FIG. 1 is a schematic view showing an example of an ink jet recording apparatus on which the ink jet recording head of the present invention can be mounted.

  In FIG. 1, the recording head cartridge 20 is mounted on the carriage 102 so as to be replaceable. The carriage 102 is guided and supported so as to reciprocate along a guide shaft 103 that extends in the main scanning direction (left-right direction in the figure) and is installed in the apparatus main body. The carriage 102 is driven by a main scanning motor 104 via a transmission mechanism such as a motor pulley 105, a driven pulley 106, and a timing belt 107, and its position and movement are controlled. On the other hand, the recording medium P is conveyed under the main scanning area of the carriage 102 by a conveying roller 109 that is rotated by driving of the conveying motor 108. Then, recording is performed by ejecting ink from a recording head provided in the recording head cartridge 20 while alternately repeating conveyance of the recording medium P and main scanning of the carriage 102.

  2A and 2B are perspective views showing the recording head cartridge 20. The recording head cartridge 20 includes a recording head 21 and ink tanks 23, 24, 25, and 26 (hereinafter referred to by reference numeral 22 if not specified) provided detachably on the recording head 21. These ink tanks 23, 24, 25, and 26 can correspond to, for example, black, cyan, magenta, and yellow inks. Then, the recording head 21 discharges ink supplied from the ink tank 22 from the discharge port according to the recording information. Here, each ink tank is detachable independently and can be individually replaced. For this reason, the running cost of recording in the ink jet recording apparatus can be reduced.

  The recording head cartridge 20 is fixedly supported by positioning means and electrical contacts of the carriage 102 mounted on the ink jet recording apparatus main body, and is detachable from the carriage. The recording head 21 includes a recording element substrate that performs recording using a heating resistor (heater) that generates thermal energy for causing film boiling to the ink in accordance with an electrical signal, ie, the bottom side of the drawing, that is, a recording medium. It has in the part which opposes P.

  FIG. 3 is a perspective view illustrating a basic configuration example of the recording element substrate. The recording element substrate 409 includes a plurality of rows of heat generating portions 50 that generate thermal energy used for ejecting ink on one surface of a Si base 10 having a predetermined thickness. With respect to the substrate 10, the discharge port forming member 60 made of a resin material and having the discharge port 15 and the ink path 51 formed by a known photolithography technique is in a state where the ink discharge port 15 faces the heat generating portion 50. Be placed. The ejection port 15 communicates with the corresponding ink supply ports 131 to 135 (referred to by reference numeral 13 if not specified) via the ink path 51. The ink supply port 13 is in the shape of a long groove extending over a range corresponding to the arrangement of the discharge ports 15 or the heat generating portions 50, and penetrates the base 10 and opens on the back side thereof. The opening on the back side corresponds to the ink communication port 407 formed in the first plate 406 and receives ink supply. In the following, the ejection port 15, the ink path 51 communicating with the ejection port 15, and the heat generating portion 50 disposed here are referred to as nozzles.

  The ink supply port 13 can be formed by a method such as anisotropic etching or sand blasting using the crystal orientation of Si. For example, in the case of the Si substrate 10 having a crystal orientation of <100> in the wafer surface direction and <111> in the thickness direction, the Si substrate 10 is approximately etched by anisotropic etching using an alkaline etching solution. Etching can proceed at an angle of 54.7 degrees. Thus, etching can be performed to a desired depth, and the ink supply port 13 which is a long groove-like through-hole can be formed. For example, KOH, TMAH, hydrazine or the like can be used as the alkaline etching solution.

  The electrical wiring for supplying power to the heat generating part 50 is formed by a known film forming technique using Al or the like. Furthermore, the electrodes 12 for supplying power to the electrical wiring are arranged along the opposite end of the recording element substrate 409, that is, along the edge perpendicular to the arrangement direction of the heat generating parts 50. The electrode 12 is provided with bumps such as Au, and is joined to the lead terminal of the electric wiring tape 412 by a thermosonic bonding method.

  The first recording element substrate 410 for black ink is also formed in the same manner as the recording element substrate 409 for color ink. However, since only one color ink (black ink) is supplied, a single ink supply is performed. It has a configuration in which it has a mouth and nozzle rows are formed on both sides thereof.

(Details of the recording head discharge port array)
Next, the second recording element substrate 409 for color ink of this embodiment has the configuration shown in detail in FIG. That is, the yellow ink discharge port array is the center, and the composition is symmetrical in the recording scanning direction in the color order, and the recording medium has cyan, magenta and magenta in both the forward scanning and the backward scanning. Ink is applied in the order of yellow. On both sides of the ink supply ports 131, 132, 134, and 135, there are respectively a row of ejection ports CL1, ML1, ML2, and CL2 that have a relatively large ink ejection amount, and ejection ports that have a relatively small ejection amount. Columns CS1, MS1, MS2 and CS2 are arranged. On the other hand, on both sides of the yellow ink supply port 133, a row of discharge ports (YL1 and YL2) having a relatively large ink discharge amount is arranged. In any row, the discharge ports are arranged in the sub-scanning direction at a density of 600 dpi, that is, a pitch of about 42 μm (1/600 inch), and the discharge ports have an arrangement pitch of the same color and the same discharge amount. It is shifted by 1/2 (about 21 μm). Accordingly, a recording resolution of 1200 dpi is realized by complementing two ejection port arrays with relatively large ink ejection amounts.

  In this embodiment, it is assumed that 128 discharge ports are arranged for any discharge port array. The discharge amount suitable for efficiently filling a large area with a small number of droplet discharges and enabling high-speed image formation is 3 to 10 pl. Therefore, in this embodiment, the ink discharge amount is relatively large. The discharge port was designed to obtain a discharge amount of 5.5 pl. On the other hand, the discharge amount suitable for high-definition and high-definition recording without graininess is 0.5 to 2 pl. Therefore, in this embodiment, the discharge port with a relatively small discharge amount is 1.3 pl. The amount was to be obtained. Yellow ink has relatively low visibility compared to cyan ink and magenta ink, and even large dots have little effect on graininess and have little effect on droplets. Only columns YL1 and YL2 are provided.

  By mounting the recording head having such an ejection port arrangement on the apparatus shown in FIG. 1, when printing is performed with particular emphasis on speed on plain paper, only the rows of ejection ports with a large ink ejection amount are used. Bidirectional recording can be performed on the image area. At this time, since the nozzle rows of the same color ink are arranged symmetrically, the ink application order can be made equal in the forward scan and the backward scan, and the occurrence of uneven color in the secondary color can be prevented. it can.

  When an image such as a photograph is formed, for example, a plurality of main scans (for example, a plurality of main scans according to a complementary pixel arrangement with respect to the same image area) while effectively using an ejection port array with a small ink ejection amount. By performing (multi-pass), an image with little graininess can be formed with high definition.

  However, as described above with reference to FIGS. 4B and 5B, if the discharge ports of the separate discharge port arrays are displaced from each other by a regular pitch or more, the formed dots are also displaced in the sub-scanning direction. Arise. Here, the effect is negligible if the ejection amount, that is, the dot diameter to be formed is sufficiently large, but the formed dot is small in the ejection port array having a small ink ejection amount, and the rate of change of the area factor in the sub-scanning direction is relatively large. Therefore, the density fluctuation in the sub-scanning direction appears greatly.

  Therefore, in this embodiment, such a problem is avoided by performing multipass printing as follows.

  Here, multi-pass printing means recording data thinned by a predetermined mask for each main scan, and then transporting the recording medium less than the width of the ejection port array range (band) in the sub-scanning direction. In this method, recording is performed by performing main scanning again. That is, a method of completing an image by a plurality of main scans with different ejection openings for recording in one image area, for example, four main scans while interposing a ¼ band recording medium. What performs is called 4-pass recording.

  In the present embodiment, in such multi-pass printing, recording dots arranged in the same column on the image, that is, in a vertical (sub-scanning direction) row with a density of 1200 dpi (in this example, horizontal (main scanning direction) 1 dot × vertical 256). A column including dots) is recorded with the same ejection port array. For this purpose, sub-scanning (recording medium conveyance) of an odd multiple of 1/1200 inch is performed between the main scans so that a dot recording density of 1200 dpi is obtained by each of the ejection port arrays having an ejection port array density of 600 dpi. To be Then, a mask pattern is applied so that the same column is recorded with the same ejection port array. For example, it can be divided into odd-numbered and even-numbered columns in the main scanning direction, and one is recorded in the ejection port array CS1 and the other is recorded in the ejection port array CS2.

  With reference to FIG. 6, how the problem caused by manufacturing variation and the like is avoided according to the present embodiment will be described by taking cyan discharge port arrays CS1 and CS2 as an example.

  FIG. 6A shows recording dots formed corresponding to the state of FIG. 4A, and recording is performed in a state where each discharge port array is mounted completely perpendicular to the guide shaft. It has been done. FIG. 6B shows recording dots formed corresponding to the state of FIG. 4B, and the recording head is inclined by an angle θ with respect to the extending direction of the guide shaft, that is, the main scanning direction. The recording is performed in a state where the discharge ports included in CS1 and CS2 are shifted by a half pitch.

  When an inclination as shown in FIG. 4B occurs, if multi-pass printing is performed with the discharge port arrays CS1 and CS2 having a small discharge amount without considering the column, as shown in the right part of FIG. 5B. In other words, there are portions where the recording dots overlap and blank portions, and the area factor changes greatly. On the other hand, according to the present embodiment, as shown in FIG. 6B, since the same column is recorded with the same ejection port array, the ejection ports are arranged between the ejection port arrays CS1 and CS2 due to manufacturing variation or the like. Even if there is a deviation, no dot formation position deviation occurs in the same column. That is, the area factor does not change because there is no portion where the recording dots overlap and no blank portion.

  Therefore, when the ejection port array with a small ink ejection amount is used to perform high-definition recording, the density fluctuation in the sub-scanning direction appears greatly, and the problem that the streak in the main scanning direction (horizontal direction) becomes conspicuous is avoided. . In addition, even if the shift amount differs for each color depending on the distance in the main scanning direction between the ejection port arrays, the problem that the overall color balance is lost due to the difference in the influence of density fluctuation for each color is also avoided. Further, regarding dynamic factors such as carriage and guide shaft vibration during main scanning, there is no problem that the density changes due to the difference in the relative position of the ejection port array in the main scanning direction. (Vertical) streak never occurs.

  As described above, according to the recording head having the ejection port array configuration of the present embodiment, the ejection port arrays having a relatively large amount of ink ejection are arranged symmetrically, so bidirectional printing without color unevenness is possible. Thus, high-speed recording can be realized. In addition, when performing multi-pass printing using an ejection port array with a small ejection volume in order to perform high image quality recording, the same column is recorded by the same ejection port array. It is possible to avoid density reduction, streaks, and image unevenness due to various factors.

  The effect of the present invention is not limited to the case where the recording head having the above-described configuration is used. For example, the present invention can be effectively applied to the case where an ink jet recording head having only a discharge port array with a small ink discharge amount is used. In this case, it suffices that at least two of the discharge port arrays are arranged, and the respective positions can be determined as appropriate. For example, when two or more ink supply ports are provided for each color, and an ejection port array with a small ink ejection amount is provided on both sides of each color, and by selecting these appropriately, the life of the head and the high-speed recording can be realized. However, the above problem can be avoided by recording the same column with the same ejection port array.

  Furthermore, the above-described problem is not limited to the case where multi-pass printing is performed, but may occur when complementing in the sub-scanning direction is performed with two ejection port arrays having a small ink ejection amount. Therefore, it is also possible to apply the processing of the present embodiment described above to all such cases. However, since multipass recording is performed when the user desires high-definition recording, the processing of this embodiment is performed when the apparatus is set to such a high-definition recording mode, and high-speed recording is performed. In such a mode, normal processing can be performed. In addition, for example, a test print may be performed, and the result may be visually checked by the user or read by the apparatus to determine whether or not there is a deviation, and according to the determination, whether or not to perform the above process may be determined. Is possible.

(Second Embodiment)
FIG. 7 shows a second embodiment of the configuration of the ejection opening array applicable to the second recording element substrate. Here, the same reference numerals are given to the parts configured in the same manner as in the first embodiment shown in FIG.

  The recording head to which the present embodiment is applied differs from the first embodiment in that the number of ejection ports and the arrangement density in the ejection port arrays CS1, CS2 and MS1, MS2 for obtaining small ejection amounts for cyan and magenta inks, respectively. It is a point that is doubled. That is, the ejection port arrays with a relatively large ink ejection amount are arranged in the sub-scanning direction at a density of 600 dpi, that is, a pitch of about 42 μm (1/600 inch), as described above. The discharge ports are shifted by 1/2 (about 21 μm) of the arrangement pitch. Accordingly, a recording resolution of 1200 dpi is realized by complementing two ejection port arrays with relatively large ink ejection amounts. On the other hand, for the ejection port arrays CS1, CS2 and MS1, MS2 with relatively small ink ejection amounts of cyan and magenta, 256 ejection ports are arranged in the sub-scanning direction at a density of 1200 dpi, that is, a pitch of about 20 μm, respectively. ing. Further, in the relationship between the ejection port arrays with a small ejection amount, there is no deviation between the ejection ports in the sub-scanning direction. An array density of 1200 dpi is possible as long as the discharge ports obtain a discharge amount of approximately 3 pl or less.

  Even in such a configuration, as in the first embodiment, since the ejection port arrays with relatively large ink ejection amounts are arranged symmetrically, bidirectional recording without color unevenness is possible, and high-speed recording is possible. Can be realized. In addition, when performing multi-pass printing using a discharge port array with a small discharge amount to perform high-quality recording, the same column recording is performed with the same discharge port array, so that static and dynamic factors can be obtained. It is possible to avoid density reduction, streaking, and image unevenness due to. Further, in the case of the first embodiment, it is premised that the recording medium conveyance performed between main scans is performed precisely. In the case of the present embodiment, the ejection port array with a small ink ejection amount ejects ink. Since the outlet arrangement density is high, the condition of the medium conveyance accuracy can be relaxed.

(Other embodiments)
In the first and second embodiments described above, in each of the ejection port arrays with a small ink ejection amount, the ejection ports are aligned in a straight line in the sub-scanning direction. However, the present invention does not necessarily require the discharge ports to be arranged in a straight line, and as long as the intended purpose of avoiding problems based on static and dynamic factors can be achieved, This includes the case where they are arranged in a range having a certain extent in the scanning direction. That is, the term “one row” as used in the present invention is not limited to the case where they are aligned in a straight line in the sub-scanning direction, but is arranged with a certain extent in the main scanning direction as long as the intended purpose is not impaired. In other words, the case where it is arranged, that is, the case where it is substantially arranged in one row is also included.

  Thus, it will be described that the case where the ejection ports are substantially arranged in one row may be included. First, the present inventors have studied how far it can be regarded as substantially one row in various forms of the ejection port arrangement that can be formed on the recording element substrate.

  FIG. 9 is a schematic plan view showing the arrangement of the ejection openings in the recording element substrate used for this study. In this example, in the same configuration as that of the recording element substrate 409, among the five ink supply ports 13 (131 to 135), adjacent three supply ports (131 to 133) are used to supply each ink. Nozzle rows were formed on both sides or one side across the mouth. The discharge ports constituting the nozzles are the same as the discharge ports with relatively small ink discharge amounts in the first and second embodiments, and a discharge amount of 1.3 pl is obtained by one discharge operation. The discharge port arrays indicated by the symbols NA1, NA2, NA3, NA4 and NA5 were arranged in order from the one located at the leftmost end of the substrate.

  Here, the ejection port array NA1 located on the left side of the ink supply port 131 and located at the leftmost end portion of the substrate has the ejection ports arranged in a staggered manner, and strictly speaking, has an array density of 600 dpi in the sub-scanning direction. The ejection ports are arranged in two rows close to each other in the main scanning direction. The arrangement pitch of these columns in the main scanning direction is 40 μm. Further, in the relationship between the columns, the ejection ports are arranged so as to be shifted by a half of the arrangement pitch in the sub-scanning direction, thereby having a recording resolution of 1200 dpi.

  FIG. 10 is a schematic diagram showing a partial enlargement of the discharge port array NA1. As shown in this figure, by alternately arranging two types of ink paths 51 having different lengths from the ink supply port on one side of the ink supply port 131, a staggered arrangement of nozzles or discharge ports 50 can be achieved. It becomes possible. That is, the nozzles or the discharge ports 50 are not closely arranged in the sub-scanning direction, and these shapes can be designed relatively freely.

  The discharge port arrays NA2, NA3, NA4, and NA5 are formed by arranging discharge ports in a straight line at a density of 600 dpi in the sub-scanning direction. Here, the ejection ports included in the ejection port arrays NA2 and NA4 are ejection ports included in the right side of the ejection port array NA1, and the ejection ports included in the ejection port arrays NA3 and NA5 are located on the left side of the ejection port array NA1. The ejection ports included in the row are arranged so as to be aligned in the main scanning direction. That is, the ejection ports included in the ejection port arrays NA2 and NA4 and the ejection ports included in the ejection port arrays NA3 and NA5 are shifted by a half of the arrangement pitch in the sub-scanning direction, that is, 1200 dpi. The distance in the main scanning direction between the ejection port arrays NA3 and NA4 is 200 μm, the distance in the main scanning direction between the ejection port arrays NA2 and NA3 is 1000 μm, and the distance in the main scanning direction between the ejection port arrays NA2 and NA5 is 2200 μm. It is.

Next, the discharge port arrays NA1 to NA5 are combined as follows, and the distance in the main scanning direction between the discharge port arrays and image deterioration (density reduction, streak, image unevenness) corresponding to the case where the largest manufacturing variation occurs. ) Was examined. The maximum manufacturing variation is assumed to be a state in which the complementary relationship between the discharge port arrays is not established when an inclination as shown in FIG. 5B occurs. That is, the displacement of the arrangement pitch in the sub-scanning direction occurs due to the relationship between the farthest ejection port arrays (CS1 and CS2) that are in a complementary relationship, and the ejection ports are aligned in the main scanning direction (completely formed dots are It is a state that overlaps with
Case 1: Recording with only the discharge port array NA1 (main scanning direction distance between the arrays: 40 μm)
Case 2: Recording with ejection port arrays NA3 and NA4 (main scanning direction distance: 200 μm)
Case 3: Recording with discharge port arrays NA2 and NA3 (main scanning direction distance: 1000 μm)
Case 4: Recording with ejection port arrays NA2 and NA5 (distance in the main scanning direction: 2200 μm)
Recording was performed by using a photographic paper having a general ink receiving layer (PR101 manufactured by Canon Inc. in this study) and forming an image using two inks of cyan and magenta. A gradation image (with gradations from highlight to solid) was recorded, and evaluation was performed based on the degree of image deterioration in the gradation range using the 1.3 pl nozzle.

  As a result, no image deterioration was observed in case 1 and case 2. In case 3, some image deterioration was observed, and in case 4, this was remarkable. Further, there was almost no difference due to the ink color.

  From the above examination results, there is no problem in terms of the image up to the staggered arrangement of the ejection ports such as the ejection port array NA1 and the both-sided arrangement with the ink supply port interposed therebetween (relationship between the ejection port arrays NA3 and NA4). It was confirmed that can be regarded as substantially one row.

  That is, in the above-described embodiment, the ejection port array with a small ink ejection amount does not necessarily require the ejection ports to be arranged in a straight line, and does not obstruct the intended purpose in the main scanning direction. Alternatively, they may be arranged with a certain extent.

  In each of the above-described embodiments, the case where the present invention is applied to a recording element substrate or a recording head having an ejection port array that ejects cyan, magenta, and yellow inks as a plurality of colors has been described. However, the color tone (color, density) to be used is not limited to this, and the order of applying the color inks can be determined as appropriate.

  Further, for yellow ink, an ejection port array having a relatively small ink ejection amount can be applied. Further, the discharge port array for black ink may not be formed on a separate recording element substrate, but may be formed on an integrated recording element substrate together with the color ink discharge port array.

  In addition, in each of the above-described embodiments, a configuration using an electrothermal conversion element that generates thermal energy that causes film boiling in ink according to a drive signal is used as an element that generates energy used to eject ink. Explained. However, as the energy generating element, an element that generates mechanical energy that increases or decreases the internal volume of the ink path communicating with the ejection port is used. The ink may be ejected and image recording may be performed.

  In addition, the above embodiments have been described on the assumption that each ejection port array extends in a direction perpendicular to the main scanning direction. However, the application of the present invention is effective even for a recording head based on the premise that the ejection port array extends with an inclination with respect to the main scanning direction. This is because, due to manufacturing variations, the discharge ports may not be positioned at regular positions in the main scanning direction due to the distance in the main scanning direction between the two discharge port arrays, which may cause image degradation. Of course, the displacement relationship between the discharge ports can be determined as appropriate.

1 is a schematic diagram illustrating an example of an inkjet recording apparatus to which the present invention can be applied. (A) And (b) is a perspective view which shows the recording head cartridge applied to the apparatus of FIG. 1 is a perspective view illustrating a basic configuration example of a recording element substrate to which the present invention is applicable. (A) shows the configuration of the ejection port array of the recording head according to the first embodiment of the present invention, and shows the state in which the recording head is mounted without tilting with respect to the main scanning direction, and (b) shows the recording. It is a figure which shows the state in which the head is mounted inclining with respect to the main scanning direction. (A) And (b) is a figure which shows the dot formed by the conventional method, respectively when the state of Fig.4 (a) and (b) arises. (A) And (b) is a figure which shows the dot formed with the method of the 1st Embodiment of this invention when the state of Fig.4 (a) and (b) arises, respectively. FIG. 5 is a diagram illustrating a configuration of an ejection port array of a recording head according to a second embodiment of the present invention. It is a figure which shows the structure of the ejection opening array of the recording head used in the examination prior to employ | adopting the structure of the modification of embodiment of this invention. It is a figure which expands and shows a part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Si base | substrate 13, 131-135 Ink supply port 15 Ejection port 20 Recording head cartridge 21 Recording head 50 Heat generating part 102 Carriage 103 Guide shaft 409 Recording element board | substrate CL1, CL2, ML1, ML2, YL1, YL2 Ink discharge amount is relative Discharge port rows CS1, CS2, MS1, MS2 discharge port rows with relatively small ink discharge amount

Claims (8)

An ink jet recording method for performing recording by scanning an ink jet recording head in which at least two rows of ejection openings for ejecting ink of the same color are arranged in a direction different from the direction of the row with respect to the recording medium. There,
An ink jet recording method, wherein recording of a portion at the same position in the scanning direction and extending in a direction orthogonal to the scanning direction is performed using the same row of ejection ports.   2. The ink jet recording method according to claim 1, wherein the ejection port ejects 0.5 to 2 pl of ink.   3. The ink jet recording head according to claim 1, further comprising at least two rows of ejection ports having the same amount of ink ejection relative to the ejection ports, with respect to the same color tone. The inkjet recording method as described.   4. The ink jet recording method according to claim 3, wherein the discharge port having a relatively large discharge amount discharges 3 to 10 pl of ink.   4. The discharge port array having a double discharge port arrangement density, wherein the discharge port column having a relatively small discharge amount is twice as large as the discharge port array having a relatively large discharge amount. The ink jet recording method according to claim 4.   The ink jet recording head ejects cyan, magenta, and yellow inks, and at least two of the ejection ports are arranged for at least the cyan and magenta color tones, respectively. The ink jet recording method according to claim 1.   In the inkjet recording head, the two rows of ejection ports for ejecting the cyan ink and the ejection for ejecting the magenta ink at positions symmetrical with respect to the row of ejection ports for ejecting the yellow ink. The inkjet recording method according to claim 6, wherein the outlet rows are respectively arranged.   8. The ink jet recording method according to claim 1, wherein the one row arrangement is an array of ejection openings within a range having a width of 200 [mu] m or less in the scanning direction. .

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