JP2010069707A - Inkjet recording device and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device eliminating an error element caused by the relative movement of a print head and a workpiece to allow ink drops to reach the workpiece with high accuracy. <P>SOLUTION: The inkjet recording device for printing and forming an image on a workpiece by an inkjet method is provided with: bridges 1a, 1b movable in an X-direction; and sliders 2a-2d movable in a Y-direction. An alignment-reaching position detecting camera 3 is mounted to the slider 2a, and head units 4a-4c equipped with print heads 8a-8c are mounted to the sliders 2b-2d. Prior to actual printing of the workpiece placed on a workpiece stage 6, test printing is performed in a test printing regions 5a-5c, and the ink reaching positions at this time are detected by the camera 3. Based on the ink reaching positions, target reaching positions in actual printing and a slider position in test printing, a print head printing start position in actual printing is computed to carry out actual printing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that forms an image using an ink jet recording method. More specifically, the present invention has a plurality of print heads and a plurality of sliders mounted with the print heads, and can be aligned at high speed and with high accuracy. The present invention relates to an ink jet recording apparatus.

  In a recording apparatus using an ink jet recording method, minute ink droplets are ejected from an ink ejection port (nozzle) of a print head. The ink droplets are ejected and adhered onto a work (an object on which a recording process is performed), and desired printing or image recording is performed. The print head is mounted on a movable body called a slider and is arranged so as to be able to scan (move) relative to the workpiece. By operating the slider and moving the print head to eject ink droplets from the nozzles above the work, an image or the like is recorded on the work.

  Such an ink jet recording apparatus can perform a recording operation in a state of being separated from the work. For this reason, it is possible to perform recording on workpieces of various materials, and since high-definition recording is possible as compared with other recording methods, development in a wide range of applications has been attempted in recent years. . For example, an ink jet recording system has begun to be used in the manufacture of color filters, organic EL, and the like, which are constituent members of a color liquid crystal display used in displays for color televisions and personal computers.

On the other hand, in the ink jet recording system, a print head having a size smaller than that of a work is used. For this reason, when recording on a large-area workpiece, it is usual to carry out the recording by transporting the workpiece or by scanning the print head. It is an important factor that determines quality. In particular, in order to employ an ink jet recording method for manufacturing a color filter, alignment accuracy in units of microns is required. Thus, for example, Patent Document 1 describes a method for adjusting the position of a print head by observing the nozzles of the print head and detecting the position of the nozzles to derive the relative relationship between the workpiece and the nozzles. Has been.
JP 2006-133396 A

  However, in the alignment method in Patent Document 1, since the nozzle and the workpiece are aligned, various temporal error factors that occur when ink droplets are ejected while the print head and the workpiece are moved relatively. Is not taken into account. That is, in the method of Patent Document 1, a time that causes an error such as a propagation time of an ejection timing signal, a response time of a print head, and an ink flight time after ink is ejected until landing on a work is not considered. Therefore, there was a problem that ink droplets could not be landed on the work with high accuracy.

  An object of the present invention is to provide an ink jet recording apparatus that can eliminate an error element caused by relative movement of a print head and a work and can land ink droplets on the work with high accuracy.

  The ink jet recording apparatus of the present invention is an ink jet recording apparatus that prints an image on a workpiece by an ink jet method, and is mounted on the bridge and movable in the Y direction. A plurality of sliders, a head unit mounted on the slider and mounted with a plurality of print heads, a region where test printing by the head unit is possible, and ejection from the nozzles of the print head during the test printing A position detecting means for detecting the landing position of the ink that has been printed, and the printing of the print head during actual printing for actually printing a predetermined image on the workpiece based on the ink landing position during the test printing. Printing start position calculating means for calculating the start position.

  In the ink jet recording apparatus of the present invention, the landing position at the time of actual printing is predicted based on the landing position of the test printing, and the printing start position of the print head at the time of actual printing is calculated. The actual printing process is performed based on the result of the test printing, and the printing process is performed in a state where an error element caused by the relative movement of the print head and the workpiece is canceled. Therefore, the ink droplet can be landed accurately at a desired position on the work, and the recording quality during actual printing can be improved.

In the ink jet recording apparatus, the position detection unit includes a print start position of the print head at the time of actual printing, a target landing position of ink at the time of actual printing, an ink landing position at the time of test printing, and a test mark. You may make it calculate based on the position of the said slider at the time of photography. Further, the position detection unit may detect an alignment mark formed on the workpiece.

  On the other hand, the inkjet recording method of the present invention includes a plurality of bridges movable in the X direction, a plurality of sliders mounted on the bridge and movable in the Y direction, and a plurality of print heads attached to the sliders. And an ink jet recording apparatus comprising an ink jet recording apparatus including the head unit, and an ink jet recording method for forming an image on a work, prior to an actual printing process for actually printing a predetermined image on the work, Test printing is performed using the same print head as the actual printing process, and the target ink landing position during actual printing, the ink landing position during test printing, and the position of the slider during test printing are set. Based on this, the printing start position of the print head at the time of actual printing is calculated.

  In the ink jet recording method of the present invention, test printing is performed prior to the actual printing process, the landing position at the time of actual printing is predicted based on the landing position and the like, and the printing start position of the print head at the time of actual printing is determined. calculate. The actual printing is performed based on the result of the test printing, and the printing process is performed in a state where error elements caused by the relative movement of the print head and the work are canceled. Therefore, the ink droplet can be landed accurately at a desired position on the work, and the recording quality during actual printing can be improved.

  In the inkjet recording method, test printing may be performed in a test printing area provided in the inkjet recording apparatus. In addition, the ink landing position at the time of the test printing may be detected by a position detecting unit attached to the slider. Furthermore, it is preferable to set the distance between the nozzle of the print head and the object to be printed, the scanning speed of the print head, and the drive voltage of the print head in the test printing under the same conditions as the actual printing process. .

  According to the ink jet recording apparatus of the present invention, since the printing start position of the print head at the time of actual printing is calculated based on the landing position of the test printing, etc., the ink droplet is accurately placed at a desired position on the workpiece at the time of actual printing. The printing position at the time of actual printing can be controlled with high accuracy. Accordingly, it is possible to improve the recording quality in the ink jet recording apparatus, and for example, the product quality is ensured even for a printing object such as a color filter that requires alignment accuracy in units of microns.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a top view showing a configuration of an embodiment of an ink jet recording apparatus of the present invention. The recording apparatus is an apparatus that prints a pattern (image) on a workpiece such as a filter base material by an inkjet recording method, and ejects ink droplets from nozzles (not shown) arranged in the print head units 4a to 4c. A desired recording process is executed on the workpiece.

  As shown in FIG. 1, the ink jet recording apparatus of the present invention includes bridges 1a and 1b movable in the X direction and sliders 2a to 2d movable in the Y direction. The bridges 1a and 1b are mounted on the frames 7a and 7b, and are installed so as to be movable in the X direction. The sliders 2a to 2d are attached to the bridges 1a and 1b and are movably installed in the Y direction. The bridges 1a and 1b and the sliders 2a to 2d are driven by driving means (not shown) using a controllable motor such as a stepping motor or a servo motor. Precision measuring means such as a linear scale is disposed on the bridges 1a and 1b and the frames 7a and 7b, and the motor is feedback-controlled based on the detection result. The bridges 1a and 1b and the sliders 2a to 2d can be simultaneously driven in the X direction and the Y direction.

  An alignment / landing position detection camera 3 (hereinafter abbreviated as camera 3) is attached to the slider 2a. This camera 3 is a photographing means for detecting the alignment mark 12 (see FIG. 3) for positioning provided on the work 11 and the landing position of the ink droplets. For example, an image processing camera such as a CCD is used. As the camera 3, either an area camera or a line camera may be used as long as the alignment mark and the ink landing position can be detected.

  The sliders 2b to 2d are equipped with print head units 4a to 4c (hereinafter abbreviated as head units 4a to 4c) having print heads 8a to 8c. Thus, the head units are mounted on a plurality of sliders. This speeds up the printing process and reduces the number of work printing steps. All the print heads 8a to 8c can be printed at the same time, and the ejection timing can be controlled independently. Further, in order to realize high-precision printing, the print heads 8a to 8c are attached in parallel to each other with an accuracy within 5 μm. For the print heads 8a to 8c, for example, a piezo-type known inkjet head is used, and at least one nozzle is installed therein. In addition, as the print heads 8a to 8c, those having known dimensions such as between nozzles are used.

  The ink jet recording apparatus of FIG. 1 is also provided with a work stage 6 on which a work can be fixed by air adsorption or the like. The work stage 6 is movable in the X direction, the Y direction, and further in the rotation direction. In addition to the vertical direction in FIG. 1, the work stage 6 has an arbitrary angle θ in the work coloring surface, that is, a plane parallel to the recording processing surface. Is also rotatable. The work stage 6 can be moved to a work set position (a position for processing the work) by a moving mechanism (not shown). Further, the work stage 6 is provided with a mechanism (not shown) capable of setting the work at an arbitrary position.

  In FIG. 1, reference numerals 5a to 5c denote test printing areas, which are used to align the head units 4a to 4c prior to the actual printing process on the workpiece. In the test printing areas 5a to 5c, the ink flying time between the area and the nozzle becomes equal to the ink flying time between the nozzle and the work when the pattern is actually printed on the work (during actual printing). So that it is set to the same height as the workpiece. Further, it is formed of a member (medium) in which the shape of the landing ink remains so that the landing position can be detected. The media in the test printing areas 5a to 5c can be appropriately replaced by an exchange mechanism such as an automatic winding type.

  In such an ink jet recording apparatus, the printing process is started as follows. FIG. 2 is a flowchart up to the start of pattern printing by the ink jet recording apparatus of the present invention. The processing of FIG. 2 and the accompanying device drive control, printing control, and other various device controls are performed by the control processing device 13 having an arithmetic processing function such as a computer, storage means, and the like. As shown in FIG. 2, first, in step S1, the work 11 is set at the work position. The work position is a reference area set as a position for processing the work, and the work 11 is fixed to the work position set on the work stage 6 in S1. At this time, a workpiece having a known shape and size and having at least two alignment marks is used.

  Next, in step S2, alignment of the workpiece is adjusted. The apparatus of the present invention can position the print heads 8a to 8c with high accuracy and is particularly effective for a workpiece that must be landed at a specific position. For this purpose, positioning of the workpiece, that is, alignment adjustment is performed. Necessary. This alignment adjustment is performed using the camera 3, and the position of the alignment mark is confirmed by the camera 3, and is repeatedly performed until the workpiece comes to a predetermined position.

  Therefore, in S2, first, the camera 3 is moved by the slider 2a and the bridge 1a to detect the alignment mark. Then, the amount of deviation between the position where the alignment mark should originally exist and the detection position is calculated, and the work stage 6 is moved to adjust the X direction, the Y direction, and the rotation direction (angle θ). In the alignment adjustment of S2, this process is repeated until the amount of deviation is within an allowable range. As a result, the workpiece can be placed at a predetermined position with high accuracy, and high-precision printing processing is also possible.

  After the alignment adjustment, the process proceeds to step S3 to perform test printing for all heads. This test printing is performed in order to predict the landing position when the pattern is actually printed, and is executed prior to the actual printing process. In this test printing, the ejection signal propagation time, the print head response time, and the ink flight time between the nozzle and the media are made equal to those in the actual printing. In this case, the printing conditions such as the distance between the workpieces, the scanning speed of the print head, and the drive voltage are set in the same manner as in actual printing. By aligning these conditions with actual printing, it is possible to obtain settings for actual processing from test results without considering discharge timing, simplifying the operation program and reducing the load on the control device. The

  In the process of step S3, first, media are set in the test printing areas 5a to 5c. Next, the sliders 2b to 2d and the bridges 1a and 1b are moved, and the print heads 8a to 8c of the print head units 4a to 4c are moved to the test printing start positions of the test printing areas 5a to 5c. The printing start position means a set position of the print heads 8a to 8c before printing by scanning the print heads 8a to 8c.

  After the print heads 8a to 8c are moved to the test printing start position, the sliders 2b to 2d are moved in the direction for pattern printing, and all the print heads 8a to 8c are moved to the test printing areas 5a to 5c. Ink is ejected. The printing conditions at this time are the same as those when the pattern is printed on the workpiece as described above. The printing is performed while moving the sliders 2b to 2d in the Y direction. Accordingly, the ink landing position depends on the X coordinate of the printing start position of the print heads 8a to 8c in the X direction, and the Y direction depends on the Y coordinate of the printing start position of the print heads 8a to 8c and the ejection timing. .

  Ink ejection timings from the print heads 8a to 8c are performed while monitoring the operations of the sliders 2b to 2d on which the head units 4a to 4c are mounted. As described above, the sliders 2b to 2d are provided with precision length measuring means such as a linear scale, and the positions of the print heads 8a to 8c are calculated by detecting this with a reading device such as an encoder. The The encoder signal is sent to control processing means such as a computer, and the slider operation is feedback-controlled based on the result of calculation processing there.

  In the test printing, since the landing positions of the ink ejected from all the print heads 8a to 8c are detected, the ejection timing is controlled so that the ink ejected from each of the print heads 8a to 8c does not land on the same place. To do. When performing test printing, the printing start position and ejection timing are recorded for each of the print heads 8a to 8c.

  After performing test printing of all the heads, the camera 3 is moved (S4), and landing coordinates are detected and acquired (S5). Thereby, the landing positions of the ink ejected from all the print heads 8a to 8c by the test printing are detected. In the inkjet recording apparatus, since the distance between the nozzles and the number of nozzles are known, by detecting the landing positions of the ink ejected from the nozzles at the extreme ends of the print heads 8a to 8c, the print heads 8a to 8c The landing positions of all nozzles can be calculated.

  Therefore, in step S4, the bridge 1a and the slider 2a are moved in the X direction and the Y direction so that the ink ejected from the nozzle at the extreme end enters the field of view of the camera 3. In step S4, the image signal obtained from the camera 3 is processed to obtain the landing position of the ink ejected from the nozzle at the end. Then, it progresses to step S6 and repeats this process until the landing coordinate of all the print heads 8a-8c is acquired.

  After detecting the landing positions of all the print heads 8a to 8c in this way, the process proceeds to step S7, and based on the results obtained in the previous steps, a mark capable of landing ink at the target landing position during actual printing. Calculate the copy start position. In the inkjet recording apparatus, since the shape and dimensions of the work are known, if the work position is determined to be a predetermined position by the alignment adjustment in S2, the target landing position of ink is calculated based on the result of the test printing after S3. It becomes possible to do. Therefore, the X and Y relative distances between the obtained landing coordinates and the target landing position at the time of test printing are obtained, and based on the results, the bridges 1a and 1b are moved in the X direction and the sliders 2b to 2d are moved in the Y direction. By performing (scanning), it becomes possible to land the ink at the target landing position at the time of actual printing.

  FIG. 3 is an explanatory diagram showing the concept of processing for calculating the printing start position at the time of actual printing from the result of the test printing. This processing is executed by the control processing device 13 which is printing start position calculation means. The Although the print head 8b will be described as an example here, the same processing is performed in the other print heads 8a and 8c. As shown in FIG. 3, the coordinates of the reference position St of the slider 2c at the time of test printing are (Tx, Ty), and when the slider 2c is at this coordinate, ejection is performed from a reference nozzle (reference nozzle) in the slider 2c. The coordinates of the ink landing position Dt (reference dot landing position) are (X2, Y2). Further, the coordinates of the target landing position Dp on the work 11 at the time of actual printing are (X1, Y1). Further, the coordinates of the slider reference position Sp at the time of actual printing for landing the ink ejected from the reference nozzle at the landing target position Dp are (Px, Py).

  In this case, the slider reference position Sp described above becomes a reference position (printing start position) at which pattern printing processing is started at the time of actual printing, and the coordinates (Px, Py) are obtained by the following equations.

Px = Tx + (X1-X2)
Py = Ty + (Y1-Y2)
That is, using the data at the time of test printing (reference coordinates St: Tx, Ty; landing position Dt: X2, Y2), the pattern printing start position Sp is calculated from the landing target position Dp (X1, Y1) at the time of actual printing. The coordinates (Px, Py) are calculated by reverse calculation. As a result, the printing start position Sp is set according to the individual characteristics of the actual machine, error elements caused by the relative movement of the print heads 8a to 8c and the work 11 are canceled, and high-precision pattern printing is possible. .

  As described above, in the inkjet recording apparatus of the present invention, the actual printing is performed prior to the actual printing, and the printing position at the time of the actual printing is controlled based on the landing position detected at that time. (For example, within 3 μm) can be aligned. Accordingly, it is possible to improve the recording quality in the ink jet recording apparatus, reduce the defective product generation rate, and reduce the product cost. In the ink jet recording apparatus, the work 11 can be aligned by one camera 3 and all head units can be aligned in the X and Y directions, and test printing can be performed with a simple apparatus configuration. Therefore, it is possible to realize high-accuracy real printing processing at a low cost.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, in the above-described embodiment, the print heads 8a to 8c using piezo-type ink jet heads are shown. However, it is also possible to use thermal or other types of print heads. In addition, although a configuration in which specific test printing areas 5a to 5c are set in the apparatus is shown, the work stage 6 can be used as the test printing areas 5a to 5c.

It is a top view which shows the structure of one Embodiment of the inkjet recording device of this invention. It is a flowchart which shows the process until the pattern printing start by the inkjet recording device of this invention. It is explanatory drawing which shows the concept of the process which calculates the printing start position at the time of real printing from the result of test printing.

Explanation of symbols

1a, 1b Bridge 2a-2d Slider 3 Alignment / landing position detection camera 4a-4c Print head unit 5a-5c Test printing area 6 Work stage 7a, 7b Frame 8a-8c Print head 11 Work 12 Alignment mark 13 Control processing device Dp Landing target position during actual printing Dt Landing position during test printing Sp Printing start position during actual printing St Reference position of slider during test printing

Claims (7)

An inkjet recording apparatus that prints an image on a work by an inkjet method,
A plurality of bridges movable in the X direction;
A plurality of sliders mounted on the bridge and movable in the Y direction;
A head unit mounted on the slider and mounted with a plurality of print heads;
An area where test printing by the head unit is possible;
Position detecting means for detecting the landing position of ink ejected from the nozzles of the print head during the test printing;
A printing start position calculating means for calculating a printing start position of the print head at the time of actual printing for actually printing a predetermined image on the workpiece based on the ink landing position at the time of the test printing. An ink jet recording apparatus comprising:   The position detecting unit is configured to print the print head at the time of actual printing based on a target landing position of ink at the time of actual printing, an ink landing position at the time of test printing, and a position of the slider at the time of test printing. 2. The ink jet recording apparatus according to claim 1, wherein a copying start position is calculated.   The inkjet recording apparatus according to claim 1, wherein the position detection unit detects an alignment mark formed on the workpiece. Inkjet recording comprising: a plurality of bridges movable in the X direction; a plurality of sliders mounted on the bridge and movable in the Y direction; and a head unit mounted on the sliders and mounted with a plurality of print heads. An inkjet recording method for forming an image on a work by an apparatus,
Prior to the actual printing process for actually printing a predetermined image on the workpiece, a test printing is performed using the same print head as the actual printing process,
Based on the target ink landing position at the time of actual printing, the ink landing position at the time of test printing, and the position of the slider at the time of test printing, the printing start position of the print head at the time of actual printing is calculated. An ink jet recording method.   5. The ink jet recording method according to claim 4, wherein the test printing is performed in a test printing area provided in the ink jet recording apparatus.   6. The ink jet recording method according to claim 4, wherein the ink landing position at the time of the test printing is detected by a position detecting means attached to the slider.   The distance between the nozzle of the print head and the object to be printed in the test printing, the scanning speed of the print head, and the drive voltage of the print head are set under the same conditions as the actual printing process. The inkjet recording method according to any one of claims 4 to 6.

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