JP2006123448A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which prevents the generation of the unevenness of a line even in an uneven operation of paper-feeding and the like. <P>SOLUTION: The printer makes printing on a recorded medium using a recording head in which a plurality of recording elements are arranged. The printer is equipped with a scan means for scanning the recording head by making the head and the recorded medium move relatively, a conveyance means for making the recorded medium move in a direction different from the scan direction in front of the recording head, a multi-pass control means for forming a printing image by performing the scanning of the recording head of multiple times on the recorded medium by controlling the scan means and the conveyance means and a means for performing mask processing for image data recorded by the multi-pass control means. For the mask data, in the beginning area overlapped with a multi-pass, a printing duty increases almost linearly, meanwhile in the last area overlapped with the multi-pass, the printing duty decreases almost linearly. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing apparatus, and more particularly to a printing apparatus that prints an image on a recording medium by scanning a head having a plurality of recording elements.

  Conventionally, in an ink jet printer that performs printing by ejecting ink droplets from a print head, since an image is formed by scanning the print head, white streaks, black streaks, etc. may occur between each scan. The print quality was extremely deteriorated. As means for solving this, a method such as multi-pass printing in which printing is performed in a plurality of times has been adopted. For example, a proposal is made in Patent Document 1 and the like.

JP 2000-108322 A

  However, although the conventional method was able to reduce it, there was a case where a certain amount of streaks was still observed. Another problem is that the printing speed is slowed by increasing the number of multi-passes in order to reduce the number of passes.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a printing apparatus that does not cause unevenness due to unevenness such as paper feeding.

  In order to achieve the above object, the present invention provides a printing apparatus that performs printing on a recording medium using a recording head in which a plurality of recording elements are arranged, by moving the recording head and the recording medium relatively. Scanning means for scanning the recording head, and conveying means for moving the recording medium in a direction different from the previous scanning direction of the recording head, and controlling the scanning means and the conveying means on the recording medium A multi-pass control means for forming a print image by scanning the recording head a plurality of times, and a means for performing mask processing on the image data recorded by the multi-pass control means, In the mask data, the print duty increases almost linearly in the first area that overlaps in multipass, and the print duty decreases almost linearly in the last area that overlaps in multipass. And said that they would.

  The present invention also relates to a printing apparatus for printing on a recording medium using a recording head in which a plurality of recording elements are arranged, and the recording head is scanned by moving the recording head and the recording medium relatively. And a scanning unit that moves the recording medium in a direction different from the previous scanning direction of the recording head, and controls the scanning unit and the conveying unit to partially overlap the recording medium. In this way, there is provided control means for forming a print image by scanning the recording head, and means for performing mask processing on image data recorded by the control means for forming the print image. Is characterized in that the print duty increases almost linearly in the first overlapping region and decreases substantially linearly in the last overlapping region.

  According to the present invention, it is possible to realize a printing apparatus in which white lines and black lines are less likely to occur without increasing the number of times of multipass printing.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 best represents the features of the present invention, and the upper diagram shows the average print duty of a mask pattern when performing a scan including two scans before and after the nth scan. The horizontal direction in the figure is the paper feed direction.

  That is, in one scan, the print duty increases almost linearly on the left side of the head in the figure, and the print duty decreases almost linearly on the right side of the head. ing.

  Hereinafter, description will be made based on the embodiment.

<Embodiment 1>
FIG. 1 shows Embodiment 1 of the present invention, and the upper diagram shows an average print duty of a mask pattern when scanning including two scans before and after centering on a certain n-th scan. The horizontal direction in the figure is the paper feed direction.

  That is, in one scan, the print duty increases almost linearly on the left side of the head of the figure, and the print duty decreases almost linearly on the right side of the head. .

  An example of a random mask to be used in this case is shown in FIG.

  The random mask shown in FIG. 5 is applied when the overlap-printed width is large as in the present embodiment. These mask patterns may be held in a non-volatile storage device in the printing apparatus, or may be set from the host computer at an arbitrary timing such as before starting printing.

  The upper and lower masks in FIG. 5 are complementary to each other, so that the cumulative print duty on the printed recording medium is averaged as shown in the lower diagram of FIG. Become.

  The upper part of FIG. 4 shows the printing duty for each scan in the case of conventional multi-pass printing, and the lower part shows the cumulative printing duty.

  In this case, the cumulative print duty is averaged by the multi-pass printing four times.

  Next, a case where unevenness occurs in paper feeding or the like will be considered.

  The upper part of FIG. 8 shows the case where each multi-pass printing is normally performed by the conventional method, and the accumulated value is constant by three scans.

  The upper part of FIG. 2 is a method according to the present invention, where each multi-pass printing is performed normally, and the accumulated value is constant by three scans.

  It can be seen that the accumulated values are constant in the numerical samples shown in FIGS.

  Next, the middle part of FIG. 2 and FIG. 8 shows the case where the ink landing points between the scans are separated due to abnormal paper feed between the scans, uneven ink discharge from the head, and the like.

  In this case, in the conventional case of FIG. 8, a decrease in density of about 1/3 is observed, which is recognized as a white streak, whereas in the case of FIG. Although a slight bulge appears, the difference between the bulge and the base portion is as small as 2.5 as seen in the center of FIG. The phenomenon in which the density of the base portion decreases is a change within a sufficiently correctable range if a mechanism for monitoring the change in print density and controlling the overall print duty is provided.

  Similarly, the lower part of FIG. 2 and FIG. 8 shows a case where the ink landing points overlap between the scans due to abnormal paper feed between the scans and uneven ink discharge from the head.

  In this case, in the conventional case of FIG. 8, an increase in density of about 1/3 is observed, which is recognized as a black streak, whereas in the case of FIG. Although a slight bulge appears, the difference between the bulge and the base portion is as small as 3.0 as seen on the right side of FIG. The phenomenon in which the density of the base portion increases in this case is also within a range that can be sufficiently corrected if a mechanism for monitoring the change in print density and controlling the overall print duty is provided.

<Embodiment 2>
FIG. 4 shows a second embodiment of the present invention.

  In the case of the present embodiment, basically, it is intended to improve the printing speed by performing single-pass printing instead of multi-pass printing. In this case, in simple single pass printing, there is a high possibility that a clear white line or black line is generated between the scans. In the present embodiment, for example, about 10 to 20 dots are overlapped in each scan. Set and apply a random mask whose printing duty changes almost linearly only to the overlapping part, and print so that the rear end of the n-th scan is gradually thinned. In this case, printing is performed so that the normal density is obtained as a result by overlapping the printing so that the tip portion gradually becomes darker.

  As the random mask used in such a case, a relatively small mask as shown in FIG. 6 is suitable for realizing high-speed printing, but any size may be used.

It is a figure which shows the printing duty in each scanning of the actual form 1 of this invention, and its accumulation. It is a figure which shows the density | concentration change when paper feeding nonuniformity etc. generate | occur | produce in this invention. It is a figure which shows the numerical data of the density | concentration change when paper feeding nonuniformity etc. generate | occur | produce in this invention. It is a figure which shows the printing duty in each scanning in this invention, and its accumulation. It is a figure which shows the example of the random mask which changes linearly used by this invention. It is a figure which shows the example of the random mask which changes linearly used by this invention. It is a figure which shows the example of the conventional printing. It is a figure which shows the density | concentration change when a paper feeding nonuniformity etc. generate | occur | produce in a prior art example. It is a figure which shows the numerical data of the density | concentration change when paper feeding nonuniformity etc. generate | occur | produce in a prior art example.

Claims (4)

  A printing apparatus that performs printing on a recording medium using a recording head in which a plurality of recording elements are arranged, and a scanning unit that scans the recording head by relatively moving the recording head and the recording medium; A transport unit that moves the recording medium in a direction different from the scanning direction of the recording head, and controls the scanning unit and the transport unit to scan the recording head a plurality of times on the recording medium; A multi-pass control means for forming a print image, and a means for performing mask processing on the image data recorded by the multi-pass control means. In the printing apparatus, the printing duty is increased almost linearly, and the printing duty is reduced almost linearly in the last region overlapped by multi-pass   A printing apparatus that performs printing on a recording medium using a recording head in which a plurality of recording elements are arranged, and a scanning unit that scans the recording head by relatively moving the recording head and the recording medium; A conveying unit that moves the recording medium in a direction different from the scanning direction of the recording head, and controls the scanning unit and the conveying unit to partially overlap the recording medium. A control unit that forms a print image by performing scanning, and a unit that performs mask processing on the image data recorded by the control unit for forming the print image, wherein the mask data is a first overlapping region; The printing apparatus is characterized in that the printing duty increases almost linearly and the printing duty decreases almost linearly in the last overlapping region.   3. The printing apparatus according to claim 1, wherein the mask data for performing the mask processing is held in a non-volatile storage device of the printing apparatus main body and can be updated from the outside at an arbitrary timing.   3. The mask data for performing the mask processing is created at an arbitrary timing by an arithmetic device in a printing apparatus main body and is held in a nonvolatile storage device in the printing apparatus main body. Printing device.

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