JP2006076219A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device in an inkjet printer required to provide an inexpensive and high definition image in these years, which can output an image having a reduced uncomfortable feeling as much as possible even if a sufficient control positional accuracy is not obtained. <P>SOLUTION: The image forming device forms an image by using an ink head having a plurality of discharge opening arrays discharging ink, by scanning the ink head in a direction orthogonal to an ink head array direction, and by discharging ink to a recording medium. The device has: an ink head movement control means for controlling a moving amount of the ink head; a recording medium moving means for moving the recording medium in a direction orthogonal to an ink head scanning direction after writing of a discharge opening array width is finished; a recording medium movement control means for controlling a moving amount of the recording medium movement means; and an image data analyzing means for analyzing an image to be recorded in the recording medium. The device makes control so that a moving amount of the recording medium is made within a range of the ink head width, and that a writing position on the recording medium is overwritten. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus and is suitably applied to an ink jet printer and a printer.

In an inkjet printer apparatus, an apparatus using a line head has been developed so that a plurality of lines can be printed at once in the paper feed direction in order to increase the printing speed.
In such an inkjet printer device having a line head capable of printing a plurality of lines at a time, the width of writing and printing by scanning the head is wide, so printing by a single head scanning is performed compared to a device that can print only a single line. The area becomes wider and the printing speed can be increased.
However, it is necessary for the paper feeding to feed the paper at a high speed and accurately the width to be printed in one scan. In the current printer, the head position accuracy is poor in the print area of the head, and white streaks and black streaks cause deterioration of image quality.
In order to cope with such a phenomenon, a method such as feedback control is introduced into the paper feed mechanism to improve the paper feed position accuracy, but the mechanism rigidity of the printer itself is low, It is difficult to realize sufficient control because the high rigidity that requires the use of an inexpensive motor to achieve a low price also increases the cost.
As methods for making printing joints inconspicuous, there are Patent Literature 1, Patent Literature 2, Patent Literature 3, and the like, and all of them correct the overlapping positions of the ink heads at the joint portions of the heads.
JP 2003-285434 A JP 2004-050445 A Japanese Patent Laid-Open No. 05-057965

  The present invention has been made in consideration of the above-described circumstances, and in recent years, in an inkjet printer apparatus or the like that requires a low-priced and high-definition image, the apparatus itself is inexpensive, so that the rigidity of the mechanism itself cannot be increased and sufficient. An object of the present invention is to provide an image forming apparatus that obtains an image output result that is as uncomfortable as possible even when accurate control position accuracy cannot be obtained.

In order to solve the above problems, the invention described in claim 1 uses an ink head in which a plurality of rows of ejection openings for ejecting ink are arranged, and scans the ink head in a direction orthogonal to the ink head arrangement direction. In an image forming apparatus that forms an image by ejecting ink onto a recording medium, an ink head movement control unit that controls the movement amount of the ink head, and a recording medium after the writing of the ejection opening array width is completed. Recording medium moving means for moving in a direction orthogonal to the ink head scanning direction, recording medium movement control means for controlling the movement amount of the recording medium moving means, and image data for analyzing an image recorded on the recording medium The recording medium movement control means makes the movement amount of the recording medium less than the ink head width and overwrites the writing position on the recording medium. And controlling.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the write data at the position to be overwritten on the recording medium is written with an ink density different from the write data at the non-overlapping place. It is characterized by that.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image data analyzing means analyzes in advance the image data to be written, and superimposes the image data based on the image data of the area to be overwritten. The number of ink head ejection ports to be written and the density at the time of writing are switched.

  According to the present invention, in an inkjet printer apparatus or the like for which a low-priced and high-definition image is recently required, the apparatus itself is inexpensive, so that the rigidity of the mechanism itself cannot be increased and sufficient control position accuracy cannot be obtained. Therefore, it is possible to provide an image forming apparatus that can obtain an image output result with as little discomfort as possible.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the ink jet printer transports a recording medium 2 such as paper by the recording medium transport device 3 and moves the ink head 1 in a direction orthogonal to the paper feed direction, and line by line according to the ink head width. Ink is ejected from the ink head 1 to form an image on the paper surface.
In this embodiment, depending on the print quality and printing speed of the image, there is a mode in which an ink head width image is printed by a single ink head scan, a mode in which the ink head width is printed while changing the print position by multiple paper feeds, etc. Exists.
This is an effective means particularly when writing an image corresponding to the ink head width by one ink head scanning used in high-speed printing.
At this time, the ink head 1 causes the ink head movement control device 4 to eject ink according to the image data while moving in a direction orthogonal to the recording medium conveyance direction.
The recording medium transport device 3 moves the paper to the next writing position after the ink head 1 has written the data for one line of the head width by the recording medium transport control device 5.
When the amount of paper movement by the recording medium transport device 3 can be moved without error within one line width written by the ink head 1, there is no deviation between the scans A, B, and C, as shown in FIG. An image is obtained in which the boundary for each head scanning line cannot be determined.

However, if an error occurs in the amount of movement by the recording medium conveyance device 3, there is a possibility that a deviation occurs between the scans A ′ and B ′ as shown in FIG.
Such “deviation” becomes, for example, “white streak” 10 in the case of a painted area, and is perceived as significant image deterioration. Further, if the scanning lines overlap, the print density of that portion becomes high, and a “black streak” is detected by humans.
Therefore, first, in order to prevent the occurrence of this “white streak”, as shown in FIG. 4, the recording medium conveyance control is performed so that the scanning lines of the ink head 1 always overlap with a certain width (reference numeral 11). The amount of movement of the recording medium 2 is controlled by the device 5.
In this way, by operating the feed amount of the recording medium 2 with respect to the ink head width, it is possible to suppress the occurrence of “white streaks” between written images by head scanning for each line.
However, in this case, the print density of the overlapped portion becomes deep and a case of “black streaks” occurs.
For this reason, as a response to “black streaks”, the image data at the time of printing is adjusted so that the print density of the overlapping portion is changed to the print density of the non-overlapping place.
For example, as shown in FIG. 5, the ink diameter of the portion 12 to be overwritten is set to ¼, and the writing data at the time of scanning each ink head is changed so that two are overlaid.
When the writing at the time of scanning the two ink heads is overlapped (reference numeral 13), when there is no positional deviation, as shown in FIG. 6, there is no positional deviation and the density is almost the same as when writing with the same ink diameter. can get.

Also, as shown in FIG. 7, even when an error occurs in the feed amount of the recording medium 2, the ink has the same ink diameter as in the case shown in FIG. It is possible to avoid a phenomenon in which “white streaks” appear for each head scanning line.
Further, a writing pattern is set in advance so as to be inconspicuous with respect to the positional deviation during conveyance of the recording medium depending on the image state and writing data.
Then, the writing data is analyzed by the image data analyzing device 6 and the optimum writing method or overlay amount is obtained for the image data at the head scanning boundary by referring to the above pattern, and these are moved to the ink head. By supplying the control device 4 and the recording medium conveyance control device 5, it is possible to obtain image printing that avoids occurrence of “white streaks” and “black streaks”.

1 is a configuration diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 6 is a diagram illustrating an image printing example when the amount of movement of the paper by the recording medium conveyance device can be moved without error within one line width written by the ink head. The figure which shows the example of image printing when the error arises in the movement amount by a recording medium conveyance apparatus. FIG. 5 is a diagram illustrating an image printing example in which the amount of movement of the recording medium is controlled so that the scanning lines of the ink head always overlap each other by a certain width. The figure which shows the example of an image printing which made the ink diameter of the part to be overwritten 1/4 and overlap | superposed two by two. The figure which shows the example of image printing overwritten when the error did not arise in recording medium feeding. The figure which shows the example of image printing overwritten when the error arises in recording medium feeding. The figure which shows the example of image printing when not having an overwriting area | region with the same ink diameter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ink head, 2 Recording medium, 3 Recording medium conveyance apparatus, 4 Ink head movement control apparatus, 5 Recording medium conveyance control apparatus, 6 Image data analysis apparatus

Claims (3)

  An image forming apparatus that uses an ink head in which a plurality of rows of ejection ports for ejecting ink are arranged, scans the ink head in a direction orthogonal to the ink head arrangement direction, and ejects ink onto a recording medium. An ink head movement control means for controlling the amount of movement of the ink head, and a recording medium movement means for moving the recording medium in a direction perpendicular to the ink head scanning direction after the writing of the ejection opening array width is completed. The recording medium movement control means for controlling the movement amount of the recording medium movement means, and the image data analysis means for analyzing the image recorded on the recording medium, wherein the recording medium movement control means An image forming apparatus comprising: controlling the amount of movement of a medium to be equal to or less than an ink head width and overwriting a writing position on a recording medium.   2. The image forming apparatus according to claim 1, wherein the writing data at the position to be overwritten on the recording medium is written with an ink density different from the writing data at the non-overlapping place. 3. The image forming apparatus according to claim 1, wherein the image data analyzing unit analyzes image data to be written in advance, and the number of ink head ejection ports to be overwritten by image data of a region to be overwritten, An image forming apparatus that switches density during writing.

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