JP2010046903A - Inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head achieving high-speed recording and high-image-quality recording, not causing density unevenness in a recorded result. <P>SOLUTION: Regarding ejection opening array groups equipped with three types of large, medium and small nozzles each having an ink ejection amount different from one another, for ejecting the same color ink droplets, the small nozzles and the medium nozzles located at the end portions of the nozzle arrays are substantially located at the same positions in the scanning direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that performs recording by ejecting ink from nozzles onto a recording medium, and more particularly to an ink jet recording head that includes three types of nozzles having different ejection amounts.

  2. Description of the Related Art In recent years, recording apparatuses that record information such as desired characters and images on a sheet-like recording medium such as paper or film are used as information output apparatuses in word processors, personal computers, facsimiles, and the like.

  Various methods are known as recording methods of the recording apparatus, but various advantages such as non-contact recording on a recording medium such as paper, easy colorization, and excellent quietness. In recent years, the ink jet system has become particularly effective. As a configuration of a recording apparatus to which this method is applied, there is a so-called serial method in which a recording head that discharges ink according to recording information is mounted and recording is performed while scanning in a direction orthogonal to the conveyance direction of the recording medium. Widely used because it is inexpensive and easy to downsize.

  Recently, along with the widespread use of digital cameras with more than 5 million pixels and higher image quality in image input devices such as high-resolution scanners, output devices are required to achieve both high-speed recording and high-quality recording. .

  FIG. 10 is a diagram showing the nozzle arrangement of the recording head 300 in the conventional inkjet recording apparatus. In an ink jet recording apparatus (hereinafter, also referred to as an ink jet recording apparatus) that performs recording by mounting a recording head, nozzles with different discharge amounts as shown in FIG. 10 are used as means for achieving both high speed recording and high image quality recording. A recording head 300 provided is proposed. The recording head 300 is effective for improving the image quality of a halftone image having a large nozzle 302 mainly used for an image region having a high density, a small nozzle 304 mainly used for an image region having a low density. A middle nozzle 303 is provided. By recording these three types of nozzles in combination, even when recording a high-density image, the recording speed does not decrease, and the gradation is smooth from the halftone to the highlight area with little graininess. It can be recorded with.

  The recording head 300 includes a plurality of ejection port groups having large, medium, and small nozzles, and the ejection port group A and the ejection port group B are configured to eject the same color ink. In the discharge port group A and the discharge port group B, the nozzles are arranged with a half-pitch shift in the arrangement direction for each nozzle size. In other words, taking a large nozzle as an example, the large nozzles in the discharge port group B are arranged so as to be interpolated between adjacent large nozzles in the discharge port group A. This makes it possible to double the number of recording dots and the recording resolution in a single recording scan for monochromatic recording, thereby enabling high-speed and high-quality recording.

  However, when the recording speed and the recording resolution are increased by such a method, the amount of image data increases, and the calculation processing time in the recording apparatus main body increases. Therefore, a technique called index control is known as image data processing means corresponding to this. Index control is a combination of a plurality of nozzles that are adjacent to each other in the nozzle arrangement direction (hereinafter, also referred to as nozzle row direction) in different nozzle groups, and performs recording on one pixel, which is applied to a recording dot arrangement pattern in one pixel. This is a technique for performing image data processing based on the assigned number.

  By this index control, the amount of data handled in the recording device or the external device that transmits image data to the recording device is reduced, and the calculation processing time and communication time can be shortened. Therefore, higher speed recording can be performed while maintaining high recording resolution.

  Also, as an application of index control, multiple dot patterns are prepared for the same image density and are combined randomly so that even if there is a discharge failure at a specific nozzle, it will not stand out in the recorded image. You can also

JP 2008-49533 A

  FIG. 11 is a diagram schematically showing the positional relationship between the discharge port group A and the discharge port group B in FIG. As described above, in the conventional recording head, the nozzles of the discharge port group A and the nozzles of the discharge port group B are arranged so as to be shifted by a half pitch for each nozzle. When recording with such a recording head, the following problems may occur.

  12A and 12B are diagrams showing patterns recorded as the same index when recording is performed by index control with a conventional recording head. A portion indicated by a square is a portion recorded as one pixel, and recording is performed in one pixel by a combination of ink droplets 403A and 403B from the middle nozzle and ink droplets 404A and 404B from the small nozzle. .

Ink droplets (hereinafter also referred to as medium dots) 403A from the middle nozzle and ink droplets (hereinafter also referred to as small dots) 404B from the small nozzle are the nozzle 303A and the ejection port group B of the ejection port group A in FIG. No. 304B was used for recording. Further, the small dots 404A and the medium dots 403B are recorded by the ejection port group A 304A and the ejection port group B 303B in FIG. FIGS. 12A and 12B differ from each other in the landing positions of the ink droplets although they are recorded as the same index.

  As described above, when the landing position changes depending on the combination of nozzles used for recording even if the index is the same, the method of filling the dots in the unit area (hereinafter also referred to as area factor) becomes unstable, and the density of the image tends to be uneven. .

  In particular, when the pattern shown in FIG. 12A is recorded, the center position of the recording dot may overlap the preceding and following pixels in the recording scanning direction. Even when such overlapping (interference) of recording dots occurs, the way of filling the area factor changes, which causes density unevenness.

  Due to the occurrence of density unevenness in this way, in an ink jet recording head having three or more types of nozzles with different ejection amounts, the combination of recording dots in index control is restricted, and an optimal image design is achieved particularly in a halftone density region. There was a risk of being disturbed. Furthermore, this density unevenness becomes more noticeable as the number of recording passes decreases in multi-pass recording in which recording of one recording width is performed by scanning a plurality of times, and there is a trade-off relationship between high-speed recording and high-quality recording. It had become.

  Accordingly, an object of the present invention is to provide an ink jet recording head that can perform high-speed recording and high-quality recording without image density unevenness in the recording result.

  Therefore, in the ink jet recording head of the present invention, a plurality of nozzles having different ejection amounts form a plurality of nozzle rows to form a plurality of nozzle groups, and at least two of the plurality of nozzle groups have the same color. In the ink jet recording head capable of ejecting ink, when the plurality of nozzles having different ejection amounts are a large nozzle, a medium nozzle, and a small nozzle, respectively, the nozzle group in the plurality of nozzle groups capable of ejecting the same color ink is arranged in the nozzle row. The deviation of the position of the center of the middle nozzle and the center of the small nozzle located at the end of the plurality of nozzle rows in the direction intersecting the nozzle row direction, which is the direction along the nozzle row direction, is adjacent to the nozzle row. In the plurality of nozzle groups that are within a distance of half the pitch of the middle nozzle and the small nozzle and are capable of discharging the ink of the same color Position of the large nozzles with each other positioned in the plurality of nozzle rows end in the direction intersecting the nozzle array direction, it has been arranged to be shifted, characterized by.

  According to the present invention, an ink jet recording head adjoins a position shift between the center of a middle nozzle and the center of a small nozzle located at the nozzle row end in a direction intersecting the nozzle row direction in a nozzle group that ejects the same color ink. Within half the distance of the middle nozzle and small nozzle pitch. Further, in the nozzle group that ejects the same color ink, the positions of the large nozzles positioned at the end portions of the plurality of nozzle rows in the direction intersecting the nozzle row direction are shifted from each other.

  As a result, an ink jet recording head capable of high-speed recording and high-quality recording without image density unevenness in the recording result could be realized.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing the structure of a recording apparatus 10 to which this embodiment can be applied. The recording apparatus 10 includes a housing 1, a carriage 3 that reciprocates in a certain direction, a paper feed mechanism 2 that supplies a recording medium 4, a paper discharge mechanism (not shown) that discharges the recording medium 4 on which an image has been recorded, and the like. It has. The recording medium 4 is conveyed in the arrow B direction orthogonal to the carriage scanning direction (arrow A direction) (hereinafter also referred to as the scanning direction).

  FIG. 2 is a perspective view showing the recording head 5 that can be mounted on the recording apparatus 10. A recording head 5 is mounted on the carriage 3 (see FIG. 1), and is fixedly supported in a predetermined state by positioning means and electrical contacts. The recording head 5 mainly includes a nozzle chip 100, a tank holder 6, ink tanks 7K, 7C, 7M, and 7Y, and a flow path (not shown) that sends ink supplied from the ink tank to the nozzle chip 100. .

  The nozzle chip 100 is provided with a plurality of nozzles capable of ejecting ink, and ejects ink onto the recording medium 4 while scanning with the carriage 3 in a direction perpendicular to the paper discharge direction (arrow B direction in FIG. 1). Ink is ejected from each ejection nozzle at a predetermined timing in accordance with a signal corresponding to recording data received from the electrical contact of the carriage 3 to perform predetermined image recording. A paper discharge mechanism (not shown) feeds the recording medium 4 supplied from the paper supply mechanism 2 by a necessary amount in synchronization with the scanning of the carriage 3, and guides image formation by the recording head 5. Then, the recording medium 4 on which recording is completed is discharged to the outside of the housing 1.

  FIG. 3 is a diagram showing the configuration of the discharge nozzles installed in the nozzle chip 100. The nozzle chip 100 includes a total of six discharge port groups (hereinafter also referred to as nozzle groups) K, C1, M1, Y, M2, and C2. The nozzle group K ejects black ink, the nozzle groups C1 and C2 eject cyan ink, the nozzle groups M1 and M2 eject magenta ink, and the nozzle group Y ejects yellow ink. Each of the nozzle groups K, C1, M1, Y, C2, and M2 is installed along the longitudinal direction of the common liquid chamber 101, and ink is supplied from the common liquid chamber 101. The discharge nozzles are arranged in a direction orthogonal to the scanning direction (arrow A direction). Ink is supplied to the common liquid chamber 101 from the back surface of the nozzle chip 100, and the back surface of the chip is connected to the ink tank of each color through the ink flow path.

  In the figure, the larger the discharge amount, the larger the circle. The large nozzle 102 having the largest discharge amount forms a row composed of only large nozzles (first nozzle row), and is installed in all nozzle groups. Here, the discharge amount of the large nozzle 102 is about 5 to 6 pl. The middle nozzle 103 having the second largest discharge amount is installed in the nozzle groups C1, C2, M1, and M2. Here, the discharge amount of the middle nozzle 103 is about 2 to 3 pl. The small nozzle 104 having the smallest discharge amount is installed in the nozzle group along the same side as the middle nozzles of C1, C2, M1, and M2. Here, the discharge amount of the small nozzle 104 is about 1 to 2 pl. The middle nozzles 103 and the small nozzles 104 are alternately arranged to form a row (second nozzle row).

  Each nozzle group may be provided with a recording nozzle portion responsible for ejection for recording and a dummy nozzle portion responsible for purposes other than recording (for example, the purpose of preventing color mixing at the end of the recording nozzle row).

  FIG. 4 shows the arrangement of a part of the nozzles of the recording head according to the present embodiment, and the arrangement of the nozzle groups C1 and C2 for ejecting cyan ink in the nozzle arrangement direction (hereinafter also referred to as nozzle row direction). It is a schematic diagram shown. In each of the nozzle groups C1 and C2, the large nozzle 102, the medium nozzle 103, and the small nozzle 104 are arranged at an interval of 600 dpi in the nozzle row direction. In each of the nozzle groups C1 and C2, the middle nozzles 103 and the small nozzles 104 are alternately arranged at an interval of 1200 dpi in the nozzle row direction.

  In the nozzle group C1, the upper end of the nozzle arrangement is the middle nozzle 103C1, and the large nozzle 102C1 is an intermediate position between the middle and small nozzles, that is, 1/2400 inches below the middle nozzle 103C1 and 1/2400 inches above the small nozzle 104C1. It is installed in the position. In the nozzle group C2, the upper end of the nozzle arrangement is the small nozzle 104C2, and the large nozzle 102C2 is installed at a position 1/2400 inch below the middle nozzle 103C2, that is, a position 1/800 inch below the small nozzle 104C2. Is done.

  The middle nozzle 103C1 positioned at the upper end of the nozzle group C1 and the small nozzle 104C2 positioned at the upper end of the nozzle group C2 are arranged on the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head. . Of course, the small nozzle 104C1 located below the middle nozzle 103C1 and the middle nozzle 103C2 located below the small nozzle 104C2 are also arranged on the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head. The same applies to the following small and medium nozzles.

  In the present embodiment, the middle nozzle and the small nozzle located at the upper end of the nozzle row are on the same line in the scanning direction, but the present invention is not limited to this. In other words, the effects of the present invention can be obtained if the deviation of the center positions of the medium nozzle and the small nozzle located at the upper end is within half the distance (1/2400 inch) of the pitch between the medium dot and the small dot in the nozzle row. Can do.

  FIG. 5 is a diagram showing an image of dot landing in the vicinity of the upper end of the nozzle when recording is performed using the nozzle group C1 and the nozzle group C2 having the nozzle arrangement of FIG. The left dot row is due to the nozzle group C1, and the right dot row is due to the nozzle group C2. The dots recorded by the large nozzle 102C1 are shown as large dots 202C1, the dots recorded by the medium nozzle 103C1 are shown as medium dots 203C1, and the dots recorded by the small nozzle 104C1 are shown as small dots 204C1. Also, the dots recorded by the large nozzle 102C2 are shown as large dots 202C2, the dots recorded by the medium nozzle 103C2 are shown as medium dots 203C2, and the dots recorded by the small nozzle 104C2 are shown as small dots 204C2.

  Here, the square part shown by the thick frame in the figure is a unit pixel in the index control, and the pitch in the nozzle row direction is 600 dpi. The recording dots corresponding to the uppermost pixel are indicated by hatching. In the recording by the nozzle group C1, the adjacent dot sets in the order from the top to the middle, large, and small form dots (203C1, 202C1, 204C1) that form one pixel. Further, in the recording by the nozzle group C2, a dot group (204C2, 203C2, 202C2) that forms one pixel is a set of dots adjacent in order from the top to the bottom.

  If dots can be landed in a unit pixel with such an arrangement, the area factor can be stabilized. For example, when one medium dot and one small dot are recorded from the nozzle group C1 and the nozzle group C2 within one pixel, when the medium dot 203C1 and the small dot 204C2 are recorded, and when the small dot 204C1 and the medium dot 203C2 are recorded And the area factor in one pixel is the same.

  Further, such dot arrangement can prevent the centers of the dots of the same size from overlapping the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head. For this reason, in the index control, any recording dot in a pixel can be combined to avoid the occurrence of unevenness due to the occurrence of dot interference between different pixels. In particular, this appears as a more remarkable effect in a recording mode of three passes or less in multi-pass recording in which recording of one recording width is performed by scanning a plurality of times.

  In addition, when a nozzle configuration having this dot arrangement is used, the recording dots at the front and rear ends of the nozzle row are not recorded on the same raster even when recording is performed by one pass. That is, the centers of the recording dots of different pixels at the connection between passes are not located on the same raster. As a result, for example, even if the entire nozzle chip 100 is shifted by θ, large recording dot interference does not occur, and the occurrence of connecting stripes is reduced.

  Further, in the nozzle arrangement of FIG. 4, the same effect as described above can be obtained even if the positions of the middle nozzle and the small nozzle are reversed in each of the nozzle groups C1 and C2. However, adopting the nozzle arrangement shown in FIG. 4 also provides the following advantages.

  In the nozzle arrangement of FIG. 4, in each nozzle group C <b> 1 and C <b> 2, the nozzle arrangement interval between the large nozzle 102 and the middle nozzle 103 and the nozzle arrangement interval between the middle nozzle 103 and the small nozzle 104 are equal. Accordingly, even if the combination of the recording nozzles is changed between the nozzle group C1 and the nozzle group C2 in the large dot + medium dot index or the medium dot + small dot index obtained by combining the recording dots having similar sizes, the recording dot position is changed. There is little change. In addition, index control with high gradation can be realized with a small density variation.

  In FIG. 4, the row of large nozzles 102 may be placed closer to the row in which medium nozzles and small nozzles are arranged. As a result, in the nozzle group for recording a common pixel, the large, medium, and small intervals can be made closer, and the area of dot interference with another pixel can be reduced.

Next, the structure of the nozzle tip of this embodiment will be described.
6 is an enlarged view of a part of the nozzle group C1 of the nozzle chip of FIG. The common liquid chamber 101C1 is filled with cyan ink supplied from an ink tank. In the figure, large nozzles 102 are installed at equal intervals on the left side of the common liquid chamber 101C1, and medium nozzles 103 and small nozzles 104 are alternately arranged at equal intervals on the right side. Ink supply to the large, medium, and small ejection nozzles is performed through the individual flow paths 112, 113, and 114 extending from the common liquid chamber 101C1. Foaming chambers 122, 123, and 124 and a heater (not shown) are installed inside the large, medium, and small discharge nozzles, respectively. Ink is ejected from the tip of the ejection nozzle to the outside by rapidly heating the ink with a heater in each foam chamber. The heating timing of the heater can be arbitrarily controlled, and ink can be ejected in a predetermined pattern according to the image signal.

  In addition, an adhesive layer 105 is laid between the lower wall of the foam chambers 122, 123, and 124 and the individual flow paths 112, 113, and 114 and a substrate provided with a heater. In the drawing, an edge ridge line of the adhesive layer 105 is indicated by a broken line. The adhesive layer 105 is installed almost all over the lower part of the wall, and is also installed in the lower part of the individual flow path 113 for the middle nozzle having no wall.

  The small nozzle 104 is installed at a position farther from the common liquid chamber 101 than the middle nozzle 103, and the individual flow path 114 for the small nozzle 104 is longer and has a higher flow resistance than the individual flow path 113 for the middle nozzle. . Therefore, the ink supply performance with respect to the small nozzle 104 is relatively lower than that of the middle nozzle 103 or the large nozzle 102, and the maximum ejection frequency is lower than that of the other nozzles.

  This means that the minimum interval at which the small nozzles 104 can continuously record in the scanning direction becomes wider (the resolution becomes lower) than the large nozzles 102 and the medium nozzles 103. As a measure against this, it is possible to secure the image density by using a recording dot pattern that combines recording of other nozzle groups of the same pixel (for example, nozzle group C2 for nozzle group C1). At this time, it is desirable that the nozzle groups that record the same pixel have the recording positions in the nozzle row direction as close as possible. Here, the positional relationship between the middle nozzle and the small nozzle with respect to the common liquid chamber 101 may be opposite to the present embodiment, that is, the small nozzle may be closer to the common liquid chamber 101 than the middle nozzle.

  In this way, the small nozzles and the middle nozzles at the end of the nozzle row are scanned in the scanning direction between the ejection port groups that eject the same color ink having the large nozzle, the middle nozzle, and the small nozzle, which are nozzles of three different ejection amounts. Are disposed at substantially the same position. As a result, an ink jet recording head capable of high-speed recording and high-quality recording without image density unevenness in the recording result could be realized.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, only the characteristic configuration will be described below.

  FIG. 7 shows the arrangement of a part of the nozzles of the recording head 5 of this embodiment, and is a diagram schematically showing the arrangement in the arrangement direction of the recording nozzles of two nozzle groups that discharge the same color. In each of the nozzle groups C3 and C4, the large nozzle 102, the medium nozzle 103, and the small nozzle 104 are arranged at an interval of 600 dpi in the nozzle row direction (arrow B direction). In each of the nozzle groups C3 and C4, the middle nozzles 103 and the small nozzles 104 are alternately arranged at an interval of 1200 dpi in the nozzle row direction. In the nozzle groups C3 and C4, nozzles of the same size are arranged on the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head 5 between the middle nozzles and the small nozzles.

  In the present embodiment, the middle nozzle and the small nozzle located at the upper end of the nozzle row are on the same line in the scanning direction, but the present invention is not limited to this. In other words, the effects of the present invention can be obtained if the deviation of the center positions of the medium nozzle and the small nozzle located at the upper end is within half the distance (1/2400 inch) of the pitch between the medium dot and the small dot in the nozzle row. Can do.

  In the nozzle group C3, the upper end is the middle nozzle 103C3, and the large nozzle 102C3 is an intermediate position between the middle nozzle 103C3 and the small nozzle 104C3, that is, 1/2400 inches below the middle nozzle 103C3 and 1/2400 inches above the small nozzle 104C3. It is installed in the position. In the nozzle group C4, the upper end is the middle nozzle 103C4, and the large nozzle 102C4 is installed at a position 1/800 inch below the middle nozzle 103C4, that is, a position 1/2400 inch below the small nozzle 104C4.

  FIG. 8 is a diagram showing a dot arrangement image in the vicinity of the upper end portion of the nozzle that is recorded using the nozzle groups C3 and C4 having the nozzle arrangement of FIG. Here, the square part shown by the thick frame in the figure is a unit pixel in the index control, and the pitch in the nozzle row direction is 600 dpi. The recording dots corresponding to the uppermost pixel are indicated by hatching. According to this recording dot arrangement, the medium dot and small dot in the same pixel are spaced at 11/1200 inch intervals regardless of which group of small dots (204C3 or 204C4) is combined with the medium dot 203C3 of the nozzle group C3. They are arranged vertically in the order of medium dots and small dots.

  The same applies to the medium dot 203C2 of the nozzle group C4, and it is possible to arrange the same dots when combining the small dots (204C3 or 204C4) of either group.

  In this way, the discharge nozzle groups having the large nozzle, the medium nozzle, and the small nozzle, which are nozzles having three different discharge amounts, discharge the same color ink, and the middle nozzle is the upper end, and the upper nozzle is arranged at the upper end. The middle nozzles are arranged at substantially the same position in the scanning direction. As a result, an ink jet recording head capable of high-speed recording and high-quality recording without image density unevenness in the recording result could be realized.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first and second embodiments, only the characteristic configuration will be described below.

  FIG. 9 shows the arrangement of a part of the nozzles of the recording head of this embodiment, and is a diagram schematically showing the arrangement of the nozzles of the four nozzle groups C5 to C8 that discharge the same color. In each of the nozzle groups C5 to C8, each of the large nozzle 102, the medium nozzle 103, and the small nozzle 104 is arranged at an interval of 600 dpi in the nozzle row direction (arrow B direction). In each of the nozzle groups C5 to C8, the middle nozzles 103 and the small nozzles 104 are alternately arranged at an interval of 1200 dpi in the nozzle row direction. The large nozzles 102 in the nozzle groups C5 to C8 are arranged in the order of 102C5, 102C6, 102C7, and 102C8 from 102C5 closest to the end at an interval of 1/2400 dpi in the nozzle row direction. In the nozzle groups C5 and C7, the upper end of the nozzle array is a middle nozzle, and the large nozzle is an intermediate position between the middle nozzle and the small nozzle, that is, 1/2400 inch below the middle nozzle and 1/2400 inch above the small nozzle. Installed in position. In the nozzle groups C6 and C8, the upper end of the nozzle row is a small nozzle, and the large nozzle 102 is installed at a position 1/2400 inch below the middle nozzle, that is, a position 1/800 inch below the small nozzle. .

  The middle nozzle 103C5 located at the upper end of the nozzle group C5 and the small nozzle 104C7 located at the upper end of the nozzle group C7 are arranged on the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head. . Further, the middle nozzle 103C6 located at the upper end of the nozzle group C6 and the small nozzle 104C8 located at the upper end of the nozzle group C8 are arranged on the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head. . Of course, the small nozzle 104C5 located below the middle nozzle 103C5 and the middle nozzle 103C7 located below the small nozzle 104C7 are also arranged on the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head. . Further, the small nozzle 104C6 located below the middle nozzle 103C6 and the middle nozzle 103C8 located below the small nozzle 104C8 are also arranged on the same line (on the same raster) in the scanning direction (arrow A direction) of the recording head. The same applies to the small and medium nozzles below.

  In the present embodiment, the middle nozzle and the small nozzle located at the upper end of the nozzle row are on the same line in the scanning direction, but the present invention is not limited to this. In other words, the effects of the present invention can be obtained if the deviation of the center positions of the medium nozzle and the small nozzle located at the upper end is within half the distance (1/2400 inch) of the pitch between the medium dot and the small dot in the nozzle row. Can do.

  By performing recording with the recording head in which the nozzles are arranged in this way, recording can be performed with higher density in one recording scan, and there is no unevenness in image density, and high-speed recording and high-quality recording are possible. An ink jet recording head capable of achieving the above has been realized.

1 is a perspective view illustrating a structure of a recording apparatus to which the present embodiment can be applied. FIG. 6 is a perspective view illustrating a recording head that can be mounted on the recording apparatus. It is the figure which showed the structure of the discharge nozzle installed in a nozzle chip. FIG. 3 is a schematic diagram illustrating a nozzle arrangement of a part of the recording head according to the first embodiment. FIG. 5 is a diagram illustrating an image of dot landing in the vicinity of an upper end portion of a nozzle when recording is performed using a nozzle group having the nozzle arrangement of FIG. 4. It is the figure which expanded and showed a part of nozzle group of the nozzle chip | tip of FIG. FIG. 10 is a diagram illustrating a partial nozzle arrangement of a recording head according to a second embodiment, and schematically illustrating an arrangement in an arrangement direction of recording nozzles of two nozzle groups that discharge the same color. FIG. 8 is a diagram showing a dot arrangement image in the vicinity of an upper end portion of a nozzle that has been recorded using a nozzle group having the nozzle arrangement of FIG. 7. FIG. 10 is a diagram illustrating a nozzle arrangement of a part of a recording head according to a third embodiment. FIG. 6 is a diagram illustrating a nozzle arrangement of a recording head in a conventional ink jet recording apparatus. It is the figure typically shown so that the positional relationship of the discharge outlet group in FIG. 10 might be understood easily. (A) And (b) is the figure which showed the pattern recorded as the same index, when recording by index control with the conventional recording head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Paper feeding mechanism 3 Carriage 4 Recording medium 5 Recording head 10 Recording apparatus 101 Common liquid chamber 102 Large nozzle 103 Medium nozzle 104 Small nozzle 105 Adhesive layer 300 Recording head

Claims (8)

A plurality of nozzles having different ejection amounts form a plurality of nozzle rows to form a plurality of nozzle groups, and at least two of the plurality of nozzle groups in the inkjet recording head capable of ejecting the same color ink ,
When the plurality of nozzles having different discharge amounts are respectively a large nozzle, a medium nozzle, and a small nozzle,
In the plurality of nozzle groups capable of ejecting the ink of the same color, the center of the middle nozzle located at the end of the plurality of nozzle rows in a direction intersecting the nozzle row direction that is a direction along the nozzle row; The positional deviation from the center of the small nozzle is within a distance of half the pitch between the middle nozzle and the small nozzle adjacent in the nozzle row,
In the plurality of nozzle groups capable of ejecting the same color ink, the positions of the large nozzles positioned at the end portions of the plurality of nozzle rows in a direction intersecting the nozzle row direction are shifted from each other.
An ink jet recording head.   2. The nozzle row is divided into a first nozzle row constituted by the large nozzles and a second nozzle row constituted by the middle nozzles and the small nozzles. The inkjet recording head described.   The inkjet recording head according to claim 2, wherein the nozzle group includes the first nozzle row and the second nozzle row.   4. The ink jet recording head according to claim 2, wherein the second nozzle row is formed by alternately arranging the middle nozzle and the small nozzle. 5.   The deviation of the position of the large nozzle in the direction intersecting with the nozzle row direction is a distance that is half the pitch of the large nozzle in the first nozzle row. An ink jet recording head according to claim 1.   The pitch between the large nozzle and the middle nozzle in the nozzle row direction and the pitch between the middle nozzle and the small nozzle in the nozzle row direction are equal to each other. The inkjet recording head described.   7. The ink jet recording head according to claim 2, wherein a pitch between the middle nozzle and the small nozzle adjacent to each other in the second nozzle row is 1/1200 inch.   The inkjet recording head according to claim 1, comprising four nozzle groups capable of ejecting the same color ink.

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