JP4415564B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus in which a plurality of nozzle arrays that eject the same ink are arranged in a scanning direction.
[0002]
[Prior art]
In general, an ink jet recording apparatus is used in large numbers as an image forming apparatus because noise during printing is relatively small and printing quality is good.
[0003]
By the way, although there are serial type and line type devices in the ink jet recording apparatus, the number of passes in the serial type ink jet recording apparatus due to ejection variation or ejection failure such as the ejection angle of the ink from the recording head and the ejection ink amount. In the recording mode with a small amount of white, white streaks can be seen in the main scanning direction, which is the moving direction of the carriage, and white streaks can be seen in the recording medium transport direction in the line type ink jet recording apparatus.
[0004]
As a countermeasure against this white streak, there has conventionally been proposed an apparatus that makes white streaks inconspicuous by providing a plurality of nozzles on the same line in the scanning direction and ejecting them alternately with respect to variations in the size of ink dots (for example, (See Patent Document 1).
Since the emission characteristics of the nozzles are different from each other, the continuity of white stripes decreases and becomes inconspicuous by alternately emitting light from a plurality of nozzles on the same line in the scanning direction.
[0005]
[Patent Document 1]
JP 2002-225265 A
[0006]
[Problems to be solved by the invention]
However, in the above-described ink jet recording apparatus, since a plurality of nozzles are arranged on the same line, the effect is small when there is a large variation in emission angle due to nozzle angle error or the like. Also, in order to prevent white lines, the quality of characters and fine lines deteriorates if the width is increased by half the pixel pitch of the print resolution.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording apparatus that can effectively prevent white streaks from occurring due to variations in ejection of ink from nozzles or ejection defects while maintaining the quality of characters and fine lines. To do.
[0008]
[Means for Solving the Problems]
  The invention described in claim 1
  An inkjet recording apparatus that forms an image by ejecting ink onto a recording medium,
  A main nozzle array in which a plurality of nozzles for ejecting ink are arranged in a direction orthogonal to the scanning direction at a pitch of an integer of the print resolution, and a sub nozzle array that ejects the same ink at the same pitch as the main nozzle array Are arranged in the scanning direction,
  In the plurality of nozzle rows arranged in the scanning direction, the nozzles of the sub nozzle row corresponding to the nozzle positions of the main nozzle row are arranged so as to be shifted from the same line in the scanning direction within a range equal to or less than half the print resolution pitch.And
The nozzles of the main nozzle row and the nozzles of the sub-nozzle row corresponding to the nozzle alternately eject ink to pixels in the scanning direction.It is characterized by being.
[0009]
  According to the first aspect of the present invention, a main nozzle row in which a plurality of nozzles for ejecting ink are arranged in a direction orthogonal to the scanning direction at a pitch of 1 / integer of the printing resolution; Sub nozzle rows that eject the same ink at the same pitch are arranged in the scanning direction, and among the plurality of nozzle rows arranged in the scanning direction, the nozzles of the sub nozzle rows corresponding to the nozzle positions of the main nozzle row are the same in the scanning direction. Since the nozzles are shifted from the line within a range of half or less of the print resolution pitch, the corresponding nozzles in a plurality of nozzle rows arranged in the scanning direction landed compared to the conventional nozzles arranged on the same line. It can cope with a wider range of ink dot variations, while maintaining the quality of characters and fine lines, due to variations in ink ejection from nozzles and ejection defects. It is possible to prevent the streaks generation effectively.In addition, since the nozzles of the main nozzle row and the nozzles of the sub nozzle row corresponding to the nozzle are alternately ejected with respect to the pixels in the scanning direction, the speed is multiple times the drive cycle of each nozzle. The image can be recorded and formed.
[0010]
According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect,
The main nozzle row is disposed in a main recording head,
The sub nozzle row is arranged in a sub recording head different from the main recording head.
[0011]
According to the second aspect of the present invention, in the ink jet recording apparatus having a configuration in which the main nozzle row is arranged in the main recording head and the sub nozzle row is arranged in a sub recording head different from the main recording head. The same effects as those of the invention described in item 1 can be achieved.
[0012]
According to a third aspect of the present invention, in the ink jet recording apparatus according to the first aspect,
The main nozzle row and the sub nozzle row are arranged in one recording head.
[0013]
According to the invention described in claim 3, in the ink jet recording apparatus having the configuration in which the main nozzle array and the sub nozzle array are arranged in one recording head, the same effect as that of the invention described in claim 1 can be obtained. it can.
[0018]
  Claim4The invention described in claim 13In the inkjet recording apparatus according to any one of the above,
  An adjustment means is provided for adjusting a shift width in a direction orthogonal to the scanning direction of the sub nozzle row with respect to the main nozzle row.
[0019]
  Claim4According to the invention described in (4), since the adjusting means for adjusting the shift width in the direction perpendicular to the scanning direction of the sub nozzle row with respect to the main nozzle row is provided, It is possible to determine an optimum shift width in which the streak is not noticeable and the quality of characters and fine lines is not deteriorated.
[0020]
  Claim5The invention described in claim 14In the inkjet recording apparatus according to any one of the above,
  All of the plurality of nozzle arrays that eject the same ink arranged in the scanning direction are arranged to be shifted from each other.
[0021]
  Claim5According to the invention described in the above, since all of the plurality of nozzle arrays that eject the same ink arranged in the scanning direction are arranged so as to be shifted from each other, it is possible to more reliably prevent the occurrence of white stripes.
[0022]
  Claim6The invention described in claim 15In the inkjet recording apparatus according to any one of the above,
  It is a line printer.
[0023]
  Claim6According to the invention described in (1), a higher effect can be obtained by applying the configuration of the present invention to a line printer.
[0024]
  Claim7The invention described in claim 16In the inkjet recording apparatus according to any one of the above,
  A light irradiating means is provided for injecting light curable ink from the nozzle and irradiating the ink landed on the recording medium with light to be cured.
[0025]
  Claim7According to the invention described in (2), since the photo-curable ink is ejected from the nozzle, and the light irradiation means for irradiating and curing the ink that has landed on the recording medium is provided, the ink is effectively fixed to the recording medium. Can do.
[0026]
  Claim8The invention described in claim7In the inkjet recording apparatus described in
  The light irradiated from the light irradiation means is ultraviolet light.
[0027]
  Claim8According to the invention described in (1), since the light irradiated from the light irradiation means is ultraviolet light, the ink can be fixed with high reliability.
[0028]
  Claim9The invention described in claim7Or8In the inkjet recording apparatus described in
  The photocurable ink is a cationic polymerization ink.
[0029]
  Claim9According to the invention described in (4), since the photocurable ink is a cationic polymerization ink, it is possible to fix the ink with high reliability. Further, the cationic polymerization ink has a light irradiation intensity by the light irradiation means. Since curing can be performed even at low illuminance, the light source can be reduced, and the ink jet recording apparatus can be made compact and low in cost.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, a line printer which is a line-type ink jet recording apparatus will be described.
[0031]
FIG. 1 shows a first embodiment of an ink jet recording apparatus according to the present invention. The ink jet recording apparatus 10 includes a line-type recording head. The recording medium 11 is conveyed in the conveying direction (scanning direction) X by the conveying device 12 and the platen 15 holds the recording medium 11 while the platen 15 holds the recording medium 11. Ink is ejected from a recording head provided at a position opposite to, and an image is formed on the recording medium 11. Note that the transport device 12 of the present embodiment has a configuration in which an annular transport belt that supports the recording medium 11 in a flat shape and transports it in the horizontal direction is rotatably stretched by a plurality of stretch rollers. Yes.
[0032]
In the recording head according to the present embodiment, a plurality of main recording heads 20Y, 20M, 20C, and 20K that mainly eject ink of a color necessary for image formation are arranged in the transport direction X. The main recording heads 20Y, 20M, 20C, and 20K are provided with a plurality of nozzles that eject ink in the width direction of the recording medium 11 that is a direction orthogonal to the transport direction X. Nozzle rows are arranged in a substantially straight line over the entire width of the recording medium 11. The plurality of main recording heads 20Y, 20M, 20C, and 20K can eject inks of different colors of yellow (Y), magenta (M), cyan (C), and black (K) toward the recording medium 11. It has become.
[0033]
In the present embodiment, a plurality of recording heads for ejecting ink of one color are provided, and the main recording heads 20Y, 20M, 20C, and 20K for the respective colors are provided downstream in the transport direction X of the recording medium 11. Sub recording heads 30Y, 30M, 30C, and 30K that assist the main recording heads 20Y, 20M, 20C, and 20K are disposed.
[0034]
The sub-recording heads 30Y, 30M, 30C, and 30K have the nozzles of the main recording heads 20Y, 20M, 20C, and 20K, ink ejection angle variations, ink ejection defects due to ink adhering to the vicinity of the ink ejection openings of the nozzles, and the like. Thus, the same ink is ejected at the same nozzle pitch as that of the main recording head so that the white streaks in the recording medium 11 are not noticeable even if the ink ejection variation, ejection failure, etc. occur, and the main recording head is complemented to eject variation. This is a recording head that solves this problem. In the present embodiment, one sub-recording head is provided for each color. As a result, the recording heads are arranged in order from the upstream side in the transport direction X of the recording medium 11, the main recording head for yellow 20Y, yellow. Eight sub recording heads 30Y, magenta main recording head 20M, magenta sub recording head 30M, cyan main recording head 20C, cyan sub recording head 30C, black main recording head 20K, and black sub recording head 30K Is provided.
[0035]
In the following description, configurations common to the main recording heads 20Y, 20M, 20C, and 20K will be described using the yellow main recording head 20Y as a representative of the main recording heads 20Y, 20M, 20C, and 20K for the respective colors. .
Similarly, configurations common to the sub recording heads 30Y, 30M, 30C, and 30K will be described using the yellow sub recording head 30Y as a representative of the sub recording heads 30Y, 30M, 30C, and 30K for the respective colors. .
The configurations described for the yellow main recording head 20Y and the yellow sub recording head 30Y are applicable to the other color main recording heads 20M, 20C, 20K and the other color sub recording heads 30M, 30C, 30K. Suppose that
[0036]
As shown in FIG. 2, the yellow main recording head 20 </ b> Y includes a main nozzle row 22 </ b> Y in which nozzles 21 </ b> Y are provided in a substantially straight line at a printing resolution pitch in a direction orthogonal to the transport direction X. Similarly to the yellow main recording head 20Y, the yellow sub-recording head 30Y also includes a sub-nozzle row 32Y in which nozzles 31Y are arranged in a substantially straight line at a printing resolution pitch in a direction orthogonal to the transport direction X.
[0037]
In the yellow main recording head 20Y and the yellow sub recording head 30Y, the corresponding nozzles 21Y and 31Y are shifted from the same line in the transport direction X of the recording medium 11 within a range of half or less of the print resolution pitch P. Has been placed. In the present embodiment, the range of the shift width Q of the nozzles 21Y, 31Y is further narrow, and is within a range of four times the standard deviation of the variation in the ejection angle of the ink ejected from the nozzle 21Y. The shift width Q of the nozzles 21Y and 31Y is more than a range that is less than half of the print resolution pitch P and a range that is within four times the standard deviation of the variation in the ejection angle of the ink ejected from the nozzle 21Y. Suppose a narrow range is applied.
By doing so, it is possible to cope with a wider variation in the landed ink dots compared to the conventional one in which the corresponding nozzles in the plurality of recording heads arranged in the scanning direction are arranged on the same line. In addition, it is possible to effectively prevent the occurrence of white streaks due to variations in the ejection of ink from the nozzles and ejection defects while maintaining the quality of characters and fine lines.
[0038]
Further, in the present embodiment, adjustment that can adjust the shift width Q in the direction orthogonal to the conveyance direction X of the respective sub recording heads 30Y, 30M, 30C, and 30K with respect to the main recording heads 20Y, 20M, 20C, and 20K of the respective colors. Means 35Y, 35M, 35C, and 35K are provided. As the adjusting means, for example, the sub recording head is movably attached to a guide rail extending in a direction orthogonal to the transport direction X, and the sub recording head attached to the guide rail drives a stepping motor. A source that adjusts the shift width Q by moving in the direction orthogonal to the conveyance direction X is conceivable. By adjusting the nozzle shift width Q for each color with the adjusting means 35Y, 35M, 35C, and 35K, it is possible to determine an appropriate shift width Q according to the characteristics of each print head.
[0039]
The ink used in this embodiment is an ink that is cured by irradiation with light, particularly an ultraviolet curable ink that is cured by irradiation with ultraviolet rays. Ultraviolet curable inks are roughly classified into radically polymerizable inks containing radically polymerizable compounds and cationically polymerizable inks containing cationically polymerizable compounds as polymerizable compounds. Both inks are used in this embodiment. As the ink used in the present embodiment, a hybrid ink in which a radical polymerization ink and a cationic polymerization ink are combined may be applied. Here, a cationic polymerization ink is used as the photocurable ink.
[0040]
As described above, since the photocurable ink is used for the ink in the present embodiment, the ink that has been ejected and landed on the recording medium 11 from the nozzles of the recording head is irradiated with light of a predetermined wavelength. A light irradiation device 16 is provided as a light irradiation means for curing. In the present embodiment, the light irradiation device 16 is provided at a position facing the recording medium 11 immediately downstream of the black sub recording head 30K positioned on the most downstream side in the conveyance direction X of the recording medium 11. In the present embodiment, an ultraviolet irradiation device that irradiates ultraviolet rays is used as the light irradiation device 16 in particular.
[0041]
In the present embodiment, roll-shaped recording paper is used as the recording medium 11. However, the present invention is not limited thereto, and various papers such as plain paper, recycled paper, and glossy paper, various fabrics, various nonwoven fabrics, resins, A cut sheet-like recording medium made of a material such as metal or glass is also applicable.
[0042]
Next, the operation of the present embodiment will be described.
First, when image information relating to an image to be recorded on the inkjet recording apparatus 10 is sent, the transport apparatus 12 operates. Specifically, when the tensioning roller of the transport device 12 rotates, the transport belt transports the recording medium 11 toward the platen 15 in the transport direction X.
[0043]
When the recording medium 11 is conveyed to the position of the platen 15, that is, the recording head, ink of each color is sequentially ejected from the main recording heads 20 Y, 20 M, 20 C, and 20 K to the recording medium 11. Further, each of the sub recording heads 30Y, 30M, 30C, and 30K also always ejects the same ink at the same nozzle pitch as the main recording head, thereby complementing the ink ejection of the main recording head. At that time, if the nozzles of the main recording head and the nozzles of the sub recording head corresponding to the nozzles alternately eject ink to the pixels in the scanning direction, the printing efficiency is good.
[0044]
In addition, one nozzle in the main recording head and a nozzle at a position corresponding to the nozzle of the main recording head in the sub recording head may eject ink to the same pixel. The nozzles of the recording head may eject ink from the nozzles of the sub recording head to the pixels adjacent to the pixels that eject ink. Further, the nozzle of the sub print head is, for example, half of the pixel adjacent to the pixel from which the nozzle at the corresponding position of the main print head ejects ink or the pixel at which the nozzle at the corresponding position of the main print head ejects ink. The ink may be ejected to a position shifted by the pixel. In addition, the ink ejection position from the nozzles of the sub-recording head may be set to an appropriate position so that white lines are not noticeable.
[0045]
In this manner, after ink ejection is performed for each color, the ink is cured by irradiating with ultraviolet rays from the light irradiation device 16. Thereafter, the recording medium 11 is transported by the transport device 12 and discharged to a discharge tray (not shown).
[0046]
[Second Embodiment]
Next, a second embodiment according to the present invention will be described. The ink jet recording apparatus according to the second embodiment is the same as that of the first embodiment except for the portions described below, and a detailed description of similar portions is omitted.
Also in this embodiment, the ink jet recording apparatus is provided with recording heads for each of the colors YMCK along the transport direction X, but the yellow recording head 40Y is used as a representative of the recording heads for each color. I will explain. The configuration described as the configuration of the yellow recording head 40Y is applicable to the recording head for other colors.
[0047]
As shown in FIG. 3, in the recording head according to the second embodiment, a plurality of nozzles 41Y arranged in a direction orthogonal to the transport direction (scanning direction) X are arranged on the yellow recording head 40Y that ejects yellow ink. Has been placed. The plurality of nozzles 41Y are arranged in a substantially straight line over the entire width of the recording medium to constitute a yellow main nozzle row 42Y that mainly ejects yellow ink necessary for image formation. The yellow main nozzle row 42Y of the present embodiment has a configuration in which the nozzles 41Y are provided on a substantially straight line at a printing resolution pitch.
[0048]
Further, the yellow main nozzle row 42Y in which the yellow main nozzle row 42Y is disposed is assisted by the yellow main nozzle row 42Y downstream of the yellow main nozzle row 42Y in the recording medium conveyance direction X. A yellow sub-nozzle row 46Y is arranged. The yellow sub-nozzle row 46Y has a configuration in which the nozzles 45Y are provided on a substantially straight line at the print resolution pitch, similarly to the yellow main nozzle row 42Y.
[0049]
The yellow sub-nozzle row 46Y has a variation in ink ejection due to a variation in ink ejection angle caused by a nozzle in the yellow main nozzle row 42Y and a problem in ink ejection due to ink adhering to the vicinity of the ink ejection port of the nozzle. In order to prevent white streaks in the recording medium from becoming noticeable even if the ink is generated, the same ink is ejected at the same nozzle pitch as the main nozzle row for yellow, and the nozzle that complements the main nozzle row for yellow and solves problems such as emission variations Is a column. In the present embodiment, one sub-nozzle row is provided for each color, and as a result, the yellow main nozzle row and the yellow sub-nozzle row are arranged in order from the upstream side in the recording medium conveyance direction X. A recording head, a magenta recording head composed of a magenta main nozzle array and a magenta sub nozzle array, a cyan recording head composed of a cyan main nozzle array and a cyan sub nozzle array, a black main nozzle array and a black sub nozzle The black recording head is composed of four recording heads and eight nozzle arrays.
[0050]
In the yellow main nozzle row 42Y and the yellow sub nozzle row 46Y, the corresponding nozzles 41Y and 45Y are arranged so as to be shifted from the same line in the recording medium transport direction X within a range of half or less of the print resolution pitch S. ing. In the present embodiment, the range of the shift width T of the nozzles 41Y and 45Y is further narrow, and is within a range of four times the standard deviation of the variation in the ejection angle of the ink ejected from the nozzle 41Y. The shift width T of the nozzles 41Y and 45Y is more preferably selected from a range that is less than half the print resolution pitch S and a range that is less than four times the standard deviation of the variation in the ejection angle of the ink ejected from the nozzle 41Y. Suppose a narrow range is applied.
By doing so, it is possible to cope with a wider variation in the landed ink dots compared to the conventional one in which the corresponding nozzles in the plurality of nozzle rows arranged in the scanning direction are arranged on the same line. In addition, it is possible to effectively prevent the occurrence of white streaks due to variations in the ejection of ink from the nozzles and ejection defects while maintaining the quality of characters and fine lines.
[0051]
Next, the operation of the present embodiment will be described.
First, when image information relating to an image to be recorded on the ink jet recording apparatus is sent, the transport apparatus operates. The specific operation is the same as that of the first embodiment.
[0052]
When the recording medium is conveyed to the position of the platen, that is, the recording head, ink of each color is sequentially ejected from each main nozzle row in each recording head to the recording medium. Also, in each sub-nozzle row in each recording head, the same ink is always ejected at the same nozzle pitch as the main nozzle row to complement the ink ejection of the main nozzle row. At that time, if the nozzles of the main nozzle row and the nozzles of the sub nozzle row corresponding to the nozzles alternately eject ink to the pixels in the scanning direction, the printing efficiency is good.
[0053]
The one nozzle in the main nozzle row and the nozzle at the position corresponding to the nozzle in the main nozzle row in the sub nozzle row may eject ink to the same pixel, or the main nozzle The nozzles in the row may eject ink from the nozzles in the sub-nozzle row to the pixels adjacent to the pixels that eject ink. Further, the nozzles of the sub-nozzle row are, for example, half pixels with respect to the pixel adjacent to the pixel from which the nozzle at the corresponding position of the main nozzle row ejects ink or the pixel at the corresponding position of the main nozzle row ejects ink. The ink may be ejected to a position shifted by a distance. In addition, the ink ejection position from the nozzles of the sub nozzle array may be set to an appropriate position so that white lines are not noticeable.
[0054]
In this way, after the ink is ejected for each color, the ink is cured by irradiating with ultraviolet rays from the light irradiation device, as in the first embodiment. Thereafter, the recording medium is transported by a transport device and discharged to a discharge tray.
[0055]
In each of the above embodiments, each recording head is composed of one line head in which substantially straight nozzle rows are arranged in the entire width in the width direction of the recording medium. A plurality of head blocks may be provided substantially in a straight line in the width direction or in a staggered pattern, and a nozzle head provided in each head block may be combined to form a line head capable of ejecting ink over the entire width of the recording medium.
[0056]
Further, in each of the above embodiments, a line printer is used as the ink jet recording apparatus. However, the present invention is not limited to this, and a serial printer may be used as the ink jet recording apparatus.
[0057]
In the first embodiment, one nozzle row is provided in each recording head. However, the present invention is not limited to this, and a plurality of rows may be provided. Further, in the first embodiment, the sub recording head is disposed on the downstream side in the scanning direction with respect to the main recording head. However, the present invention is not limited to this, and the sub recording head is disposed on the upstream side in the scanning direction with respect to the main recording head. May be.
[0058]
Furthermore, the recording head according to the first embodiment is configured such that an image having a printing resolution pitch is formed by one nozzle row provided in one main recording head. However, the present invention is not limited to this. Instead, the main recording head may be composed of a plurality of recording heads in which nozzles are arranged at a pitch of 1 / integer of the printing resolution. For example, the main recording head is composed of two recording heads having a nozzle pitch that is a half of the printing resolution, and one of the two recording heads is located at an intermediate position between the other nozzles. It may be arranged so that. In the case where the main recording head is composed of a plurality of recording heads, the sub recording head is also composed of a corresponding number of recording heads, and is adjacent to each recording head constituting the main recording head in the scanning direction. The recording heads constituting the sub recording head are respectively arranged on the upstream side or the downstream side.
[0059]
Further, in the first embodiment, one sub recording head is provided for one main recording head of each color. However, the present invention is not limited to this, and a plurality of sub recording heads may be provided for one main recording head of each color. good. In this case, if all of the recording heads for the same ink arranged in the scanning direction are arranged so as to be shifted from each other in the direction orthogonal to the scanning direction, it is possible to cope with various ink emission variations.
[0060]
In the recording head according to the second embodiment, the sub nozzle row is arranged on the downstream side in the scanning direction with respect to the main nozzle row. However, the present invention is not limited thereto, and the sub nozzle row is located on the upstream side in the scanning direction with respect to the main nozzle row. It may be arranged.
[0061]
Furthermore, the recording head according to the second embodiment is configured such that an image having a print resolution pitch is formed by one main nozzle row provided in one recording head. However, the present invention is not limited to this. Alternatively, the main nozzle row may be composed of a plurality of nozzle rows in which the nozzles are arranged at a pitch of 1 / integer of the printing resolution. For example, the main nozzle row is composed of two nozzle rows having a nozzle pitch that is a half of the print resolution, and one of the two nozzle rows is an intermediate position between the other nozzles. It may be arranged so that. When the main nozzle row is composed of a plurality of nozzle rows, the sub nozzle row is also composed of a corresponding number of nozzle rows, and is adjacent to each nozzle row constituting the main nozzle row upstream in the scanning direction. The nozzle rows constituting the sub nozzle rows are respectively arranged on the side or downstream side.
[0062]
Furthermore, in the second embodiment, the number of sub nozzle rows in one main nozzle row is one, but the present invention is not limited to this, and a plurality of rows may be provided. In this case, if all of the plurality of nozzle arrays that eject the same ink arranged in the scanning direction are shifted from each other in the direction perpendicular to the scanning direction, it is possible to cope with various ink ejection variations. good.
[0063]
As described above, according to the ink jet recording apparatus of each of the embodiments described above, a plurality of nozzles for ejecting ink are arranged in a direction orthogonal to the scanning direction at a pitch of 1 / integer of the printing resolution. A nozzle row and a sub nozzle row that ejects the same ink at the same pitch as the main nozzle row are arranged in the scanning direction, and a plurality of nozzle rows arranged in the scanning direction correspond to the nozzle positions of the main nozzle row The nozzles are arranged so as to be shifted from the same line in the scanning direction within a range equal to or less than half of the printing resolution pitch, so that the corresponding nozzles in a plurality of nozzle rows arranged in the scanning direction are arranged on the same line. Compared to those of the nozzles, it can handle a wider range of ink dots that have landed, while maintaining the quality of characters and fine lines. It is possible to effectively prevent the white streaks caused by emission variations or injection defects like the link.
[0064]
In the first embodiment, in the ink jet recording apparatus having the configuration in which the main nozzle row is arranged in the main recording head and the sub nozzle row is arranged in a sub recording head different from the main recording head, the above-described operation is performed. There is an effect.
[0065]
Furthermore, in the second embodiment, the above-described effects can be achieved in an ink jet recording apparatus having a configuration in which the main nozzle row and the sub nozzle row are arranged in one recording head.
[0066]
Furthermore, in each of the above-described embodiments, the range of the nozzle shift width is set to be within four times the standard deviation of the variation in the ejection angle of the ink ejected from the nozzle. It can be defined, and white streaks due to variations in ink ejection from nozzles can be prevented with high probability while maintaining the quality of characters and fine lines.
[0067]
In each of the above-described embodiments, the nozzles of the main nozzle row and the nozzles of the sub nozzle row corresponding to the nozzle alternately eject ink to the pixels in the scanning direction. An image can be formed by recording at a speed multiple of the driving cycle.
[0068]
Furthermore, in the first embodiment, the adjusting means for adjusting the shift width in the direction orthogonal to the scanning direction of the sub nozzle row with respect to the main nozzle row is provided, so that it matches the emission characteristics of the nozzle row actually arranged. It is possible to determine an optimum shift width in which white lines are not noticeable and the quality of characters and fine lines does not deteriorate.
[0069]
Furthermore, when all of the plurality of nozzle arrays that eject the same ink arranged in the scanning direction are arranged so as to be shifted from each other, the occurrence of white stripes can be prevented more reliably.
[0070]
In each of the above-described embodiments, a higher effect can be obtained by applying the configuration of the present invention to a line printer.
[0071]
Further, in each of the above-described embodiments, there is provided a light irradiation means for injecting light curable ink from the nozzle and irradiating the ink that has landed on the recording medium to cure it, so that the ink is effectively fixed to the recording medium. Can be made.
[0072]
Furthermore, in each of the above-described embodiments, the light irradiated from the light irradiating means is ultraviolet light, so that the ink can be fixed with high reliability.
[0073]
In each of the above-described embodiments, since the photocurable ink is a cationic polymerization ink, it is possible to fix the ink with high reliability. Further, the cationic polymerization ink is irradiated with light by a light irradiation unit. Since curing can be performed even when the intensity is low, the light source can be reduced, and the ink jet recording apparatus can be made compact and low in cost.
[0074]
The present invention is not limited to the above-described embodiments, and various improvements and design changes may be made without departing from the spirit of the present invention.
[0075]
【The invention's effect】
  According to the first aspect of the present invention, a main nozzle row in which a plurality of nozzles for ejecting ink are arranged in a direction orthogonal to the scanning direction at a pitch of 1 / integer of the printing resolution; Sub nozzle rows that eject the same ink at the same pitch are arranged in the scanning direction, and among the plurality of nozzle rows arranged in the scanning direction, the nozzles of the sub nozzle rows corresponding to the nozzle positions of the main nozzle row are the same in the scanning direction. Since the nozzles are shifted from the line within a range of half or less of the print resolution pitch, the corresponding nozzles in a plurality of nozzle rows arranged in the scanning direction landed compared to the conventional nozzles arranged on the same line. It can cope with a wider range of ink dot variations, while maintaining the quality of characters and fine lines, due to variations in ink ejection from nozzles and ejection defects. It is possible to prevent the streaks generation effectively.In addition, since the nozzles of the main nozzle row and the nozzles of the sub nozzle row corresponding to the nozzle are alternately ejected with respect to the pixels in the scanning direction, the speed is multiple times the drive cycle of each nozzle. The image can be recorded and formed.
[0076]
According to the second aspect of the present invention, in the ink jet recording apparatus having a configuration in which the main nozzle row is arranged in the main recording head and the sub nozzle row is arranged in a sub recording head different from the main recording head. The same effects as those of the invention described in item 1 can be achieved.
[0077]
According to the invention described in claim 3, in the ink jet recording apparatus having the configuration in which the main nozzle array and the sub nozzle array are arranged in one recording head, the same effect as that of the invention described in claim 1 can be obtained. it can.
[0080]
  Claim4According to the invention described in (4), since the adjusting means for adjusting the shift width in the direction perpendicular to the scanning direction of the sub nozzle row with respect to the main nozzle row is provided, It is possible to determine an optimum shift width in which the streak is not noticeable and the quality of characters and fine lines is not deteriorated.
[0081]
  Claim5According to the invention described in the above, since all of the plurality of nozzle arrays that eject the same ink arranged in the scanning direction are arranged so as to be shifted from each other, it is possible to more reliably prevent the occurrence of white stripes.
[0082]
  Claim6According to the invention described in (1), a higher effect can be obtained by applying the configuration of the present invention to a line printer.
[0083]
  Claim7According to the invention described in (2), since the photo-curable ink is ejected from the nozzle, and the light irradiation means for irradiating and curing the ink that has landed on the recording medium is provided, the ink is effectively fixed to the recording medium. Can do.
[0084]
  Claim8According to the invention described in (1), since the light irradiated from the light irradiation means is ultraviolet light, the ink can be fixed with high reliability.
[0085]
  Claim9According to the invention described in (4), since the photocurable ink is a cationic polymerization ink, it is possible to fix the ink with high reliability. Further, the cationic polymerization ink has a light irradiation intensity by the light irradiation means. Since curing can be performed even at low illuminance, the light source can be reduced, and the ink jet recording apparatus can be made compact and low in cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing an ink jet recording apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a recording head in the ink jet recording apparatus according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a recording head in an ink jet recording apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
10 Inkjet recording device
11 Recording media
12 Conveying device
15 Platen
16 Light irradiation device (light irradiation means)
20Y, 20M, 20C, 20K Main recording head
21Y, 31Y, 41Y, 45Y nozzle
30Y, 30M, 30C, 30K Sub-recording head
35Y, 35M, 35C, 35K adjustment means
40Y recording head
22Y, 42Y main nozzle row
32Y, 46Y sub nozzle array
P, S Print resolution pitch
Q, T Nozzle shift width
X Transport direction (scanning direction)

Claims (9)

An inkjet recording apparatus that forms an image by ejecting ink onto a recording medium,
A main nozzle array in which a plurality of nozzles for ejecting ink are arranged in a direction orthogonal to the scanning direction at a pitch of an integer of the print resolution, and a sub nozzle array that ejects the same ink at the same pitch as the main nozzle array Are arranged in the scanning direction,
In the plurality of nozzle rows arranged in the scanning direction, the nozzles of the sub nozzle row corresponding to the nozzle positions of the main nozzle row are arranged so as to be shifted from the same line in the scanning direction within a range equal to or less than half the print resolution pitch. And
An ink jet recording apparatus, wherein the nozzles of the main nozzle row and the nozzles of the sub nozzle row corresponding to the nozzle alternately eject ink to pixels in the scanning direction . The inkjet recording apparatus according to claim 1, wherein
The main nozzle row is disposed in a main recording head,
The ink jet recording apparatus, wherein the sub nozzle row is disposed in a sub recording head different from the main recording head. The inkjet recording apparatus according to claim 1, wherein
An ink jet recording apparatus, wherein the main nozzle array and the sub nozzle array are arranged in one recording head. In the ink jet recording apparatus according to any one of claims 1 to 3 ,
An ink jet recording apparatus comprising: an adjusting unit that adjusts a shift width in a direction orthogonal to a scanning direction of the sub nozzle row with respect to the main nozzle row. In the ink jet recording apparatus according to any one of claims 1 to 4 ,
An inkjet recording apparatus, wherein all of the plurality of nozzle arrays that eject the same ink arranged in the scanning direction are arranged so as to be shifted from each other. In the ink jet recording apparatus according to any one of claims 1 to 5 ,
An ink jet recording apparatus which is a line printer. In the ink jet recording apparatus according to any one of claims 1 to 6 ,
An ink jet recording apparatus comprising: a light irradiating means for injecting light curable ink from the nozzle and irradiating the ink landed on the recording medium with light to cure. The inkjet recording apparatus according to claim 7 , wherein
An ink jet recording apparatus, wherein the light irradiated from the light irradiation means is ultraviolet light. In the ink jet recording apparatus according to claim 7 or 8 ,
An ink jet recording apparatus, wherein the photocurable ink is a cationic polymerization ink.

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