JP2007144665A - Liquid droplet delivering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the amount of ink consumed by delivering ink droplets to aim recovery of delivering performance of a nozzle and formation of a resist pattern, and to improve the through-put of print outputting by shortening the recovery of the delivering performance of the nozzle and a time necessary for registration controlling. <P>SOLUTION: A recording head 32 performs delivering the ink droplets to aim the recovery of the delivering performance of the nozzle to a conveying belt 28 based on resist pattern data, to form resist patterns 1Y, 1M, 1C and 1K on the conveying belt 28. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid droplet ejection apparatus that records an image by ejecting liquid droplets from a liquid droplet ejection head onto a recording medium conveyed by a conveyance unit.

  In an ink jet printer as a droplet discharge device, if the time during which ink droplets are not discharged becomes long, the viscosity of the ink increases in the recording head and the discharge performance of the nozzles deteriorates. In severe cases, clogging occurs. For this reason, a so-called dummy jet (preliminary ejection) for ejecting ink droplets is performed before printing or between pages on a paper transport belt, in an ink receiver, or in a cap of a maintenance mechanism (see, for example, Patent Document 1). .

  In addition, the paper transport speed is affected by the mounting position accuracy of each recording head, frame deformation, installation conditions, environmental fluctuations, manufacturing variations of the roll that drives the paper transport belt, and the roll diameter and eccentricity due to temperature changes. Fluctuates, and the recording position of the image by each recording head shifts, resulting in color misregistration. For this reason, ink droplets are ejected from each recording head onto the conveying belt to form a test pattern for correcting misalignment, and this test pattern is read by a sensor, and the ejection timing of each recording head is corrected based on the read result. Thus, color misregistration is corrected (for example, see Patent Document 2).

That is, the ink jet printer frequently discharges ink droplets unrelated to image recording, and there is a problem in that the amount of ink consumption increases unnecessarily. In addition, various cycles such as dummy jet and color misregistration correction must be performed before starting image recording or between pages, resulting in a problem that throughput of print output decreases.
JP 2000-127362 A JP 2003- 211770 A

  The present invention has been made in consideration of the above facts, and reduces the amount of liquid consumed by ejection of droplets other than image recording, reduces the time required for operations other than image recording, and reduces print output. Increase throughput.

  The liquid droplet ejection apparatus according to claim 1, a conveyance unit that holds and conveys a recording medium, and records an image by ejecting liquid droplets based on image data to a recording medium that is conveyed by the conveyance unit, A plurality of droplet discharge heads for forming a test pattern by discharging droplets to the transport unit based on test pattern data; a pattern reading unit for reading a test pattern formed on the transport unit; and the pattern And a positional deviation correction unit that corrects a deviation of an image recording position by each droplet ejection head based on a reading result of the reading unit, wherein the liquid droplet ejection head has a nozzle ejection performance. The method is characterized in that the discharge of the droplets for recovering the ink is performed on the transport unit based on the test pattern data.

  In the droplet discharge device according to the first aspect, the droplet discharge head discharges the droplet based on the image data to the recording medium transported by the transport unit. As a result, an image is recorded on the recording medium.

  The droplet discharge head discharges droplets to the transport unit based on the test pattern data. As a result, a test pattern is formed on the conveying means. Then, the test pattern formed on the conveying unit is read by the pattern reading unit, and the positional deviation correcting unit corrects the deviation of the recording position of the image by each droplet discharge head based on the reading result of the pattern reading unit. To do.

  Here, the liquid droplet ejection head ejects liquid droplets in order to restore the ejection performance of the nozzles, and the liquid droplets are ejected to the transport unit based on the test pattern data. That is, a test pattern for correcting misalignment is formed using droplets ejected for the purpose of restoring the ejection performance of the nozzle. Thereby, the consumption of liquid can be suppressed. In addition, since the nozzle discharge performance recovery cycle and the misalignment test pattern formation cycle are performed simultaneously, the time required for the nozzle discharge performance recovery cycle and the misalignment correction control cycle can be reduced, and the print output throughput can be reduced. Can be improved.

  The droplet discharge device according to claim 2 is the droplet discharge device according to claim 1, wherein at least outside the reading range of the reading means, the droplet discharge ratio of all nozzles in each droplet discharge head And the test pattern is configured so that the droplet ejection ratios of the plurality of droplet ejection heads are uniform.

  In the droplet discharge device according to claim 2, the test pattern is configured so that the droplet discharge ratios of all the nozzles are equal in each droplet discharge head at least outside the reading range of the reading unit, Differences in ejection performance between nozzles in each droplet ejection head are suppressed. Further, at least outside the reading range of the reading means, the test pattern is configured so that the droplet discharge ratios of the plurality of droplet discharge heads are uniform, and the difference in discharge performance among the plurality of droplet discharge heads Is suppressed.

  The droplet discharge device according to claim 3 is the droplet discharge device according to claim 1, wherein the droplet discharge ratio of all the nozzles in each droplet discharge head is uniform, and a plurality of the droplet discharge devices The test pattern is configured such that the droplet discharge ratio of the droplet discharge head is uniform.

  In the droplet discharge device according to claim 3, the test pattern is configured so that the droplet discharge ratios of all the nozzles in each droplet discharge head are uniform, and the nozzles in each droplet discharge head are arranged. Differences in discharge performance are suppressed. In addition, the test pattern is configured so that the droplet ejection ratio between the plurality of droplet ejection heads is uniform, and the difference in ejection performance between the plurality of droplet ejection heads is suppressed.

  Since the present invention is configured as described above, it is possible to reduce the amount of liquid consumed by discharging droplets other than image recording. In addition, since the time required for operations other than image recording can be shortened, the throughput of print output can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an ink jet recording apparatus 12 according to a first embodiment of the present invention. A paper feed tray 16 is provided in the lower part of the casing 14 of the ink jet recording apparatus 12, and the sheets P stacked in the paper feed tray 16 can be taken out one by one by a pickup roll 18. The taken paper P is transported by a plurality of transport roller pairs 20 constituting a predetermined transport path 22.

  An endless transport belt 28 is stretched around the drive roll 24 and the driven roll 26 above the paper feed tray 16. A recording head array 30 is disposed above the conveyor belt 28 and faces the flat portion 28F of the conveyor belt 28. This opposed area is an ejection area SE where ink droplets are ejected from the recording head array 30. The sheet P transported along the transport path 22 is held by the transport belt 28 and reaches the discharge area SE, and ink droplets corresponding to image information are attached from the recording head array 30 in a state of facing the recording head array 30. The

  In this embodiment, the recording head array 30 has a long shape in which the effective recording area is equal to or larger than the width of the paper P (the length in the direction orthogonal to the transport direction), and is yellow (Y) and magenta (M). , Four ink jet recording heads (hereinafter referred to as recording heads) 32 corresponding to the four colors of Sian (C) and Black (K) are arranged along the transport direction, and a full color image can be recorded. ing.

  Each recording head 32 is driven by a head driver 33 (see FIG. 4). As shown in FIG. 4, the control unit 100 is connected to the head driver 33, and the control unit 100 is connected to the host computer 110. The control unit 100 includes a memory 102 and a CPU 104. When image data is transmitted from the host computer 110 to the control unit 100, the control unit 100 stores the image data in the memory 102. In addition, resist pattern data is stored in the memory 102 in advance, and the CPU 104 transmits image data and resist pattern data to the head driver 33. This point will be described later in detail.

  The head driver 33 determines the ink droplet ejection timing and the ink ejection port (nozzle) to be used according to the data received from the control unit 100, and sends a drive signal to the recording head 32. As a result, ink droplets are ejected from the ink ejection port to the paper P based on the image data, and an image is recorded on the paper P. Also, the ink droplets from the ink ejection port to the transport belt 28 are based on the resist pattern data. The resist patterns 1Y, 1M, 1C, and 1K (see FIG. 6) are formed on the conveyor belt 28.

  The recording head array 30 may be fixed in a direction orthogonal to the transport direction. However, if the recording head array 30 is configured to move as necessary, an image with higher resolution can be obtained by multi-pass image recording. Or the failure of the recording head 32 is not reflected in the recording result.

  Four maintenance units 34 corresponding to the respective recording heads 32 are arranged on the upstream side of the recording head array 30. As shown in FIG. 2, when performing maintenance on the recording head 32, the recording head array 30 is moved upward, and the maintenance unit 34 moves into the gap formed between the conveyance belt 28 and enters. . Then, a predetermined maintenance operation (suction, wiping, capping, etc.) is performed while facing the nozzle surface.

  As shown in FIG. 3, a charging roll 36 to which a power source 38 is connected is disposed on the upstream side of the recording head array 30. The charging roll 36 is driven while sandwiching the conveyance belt 28 and the paper P with the driven roll 26, and moves between a pressing position for pressing the paper P against the conveyance belt 28 and a separation position separated from the conveyance belt 28. It is possible. At the pressing position, a predetermined potential difference is generated between the grounded driven roll 26 and the sheet P can be charged and electrostatically attracted to the transport belt 28.

  A separation plate 40 is disposed on the downstream side of the recording head array 30 and separates the paper P from the conveyance belt 28. The peeling plate 40 can be brought into contact with and separated from the conveyance belt 28 and abuts on the conveyance belt 28 only when the paper P passes. As shown in FIG. 1, the peeled paper P is transported by a plurality of discharge roller pairs 42 that constitute a discharge path 44 on the downstream side of the peeling plate 40, and is discharged on the top of the housing 14. It is discharged to the tray 46.

  Further, as shown in FIG. 3, a cleaning blade 48 is disposed on the downstream side of the peeling plate 40 in the belt rotation direction. The cleaning blade 48 can be brought into contact with and separated from the transport belt 28, contacts the transport belt 28 at a predetermined timing such as during a dummy jet, and cleans ink or the like adhering to the transport belt 28. The cleaning blade 48 fulfills the same function even when it is always in contact.

  As shown in FIGS. 1 and 2, an ink tank 35 that stores ink of each color is disposed above the recording head array 30. Each recording head 32 is connected to each ink tank 35.

  Further, as shown in FIGS. 3 and 5, a pair of optical sensors 50 are disposed on the downstream side of the recording head array 30 and on the upstream side of the driven roll 24. Each optical sensor 50 includes a light projecting sensor 50A and a light receiving sensor 50B which are opposed to each other with the conveyor belt 28 therebetween, and each optical sensor 50 has a width direction (rotational direction) of the conveyor belt 28. It is disposed on one end side and the other end side in the (perpendicular direction).

  Here, the conveyance belt 28 is formed of a material having high translucency such as transparent PET, and the light projected from the light projecting sensor 50A passes through the conveyance belt 28 and enters the light receiving sensor 50B. The resist patterns 1Y, 1M, 1C, and 1K (see FIG. 6) formed on the conveyor belt 28 are detected by the optical sensor 50. When the conveyor belt 28 does not transmit light, the light receiving sensor is formed of a reflective sensor and detects a resist pattern.

  As shown in FIG. 6, the resist patterns 1Y, 1M, 1C, and 1K are straight lines extending from one end side to the other end side in the width direction along the width direction of the transport belt 28, and 1K from the upstream side in the transport direction A. Arranged in the order of 1C, 1M, 1Y. That is, the resist patterns 1Y, 1M, 1C, and 1K are formed outside the detection range of the optical sensor 50.

  Further, as shown in FIG. 4, a registration control unit 54 is connected to the optical sensor 50. The registration control unit 54 determines the registration shift amount from the timing when the optical sensor 50 detects the resist patterns 1Y, 1M, 1C, and 1K, corrects the ejection timing of the recording head 32, and corrects the K color. The Y, M, and C color registration shift (color shift) is corrected. In addition to the above-described correction of the ejection timing, there is also a method of shifting the image data or adjusting the position of the recording head array 30.

  Here, a registration control method and a dummy jet method will be described with reference to the flowchart of FIG.

  First, when the control unit 100 receives a print job from the host computer 110, a processing routine is started and the process proceeds to step 100. In step 100, the maintenance unit 34 is moved to the upstream side of the recording head array 30, and the recording head array 30 is lowered to the image recording position. Further, the cleaning blade 48 is brought into contact with the conveyance belt 28. Then, the process proceeds to step 102.

  In step 102, the paper P is sent out from the paper feed tray 16 and a dummy jet is performed from the recording head 32 onto the conveying belt 28 until the paper P reaches the conveying belt 28. The discharge performance is restored. At this time, the dummy jet by the recording head 32 is performed based on the resist pattern data, and the resist patterns 1Y, 1M, 1C, and 1K shown in FIG. Then, the process proceeds to step 104.

  In step 104, the resist patterns 1Y, 1M, 1C, and 1K are read by the optical sensor 50. Here, since the resist patterns 1Y, 1M, 1C, and 1K are arranged in the order of 1K, 1C, 1M, and 1Y from the upstream side in the transport direction A, the order detected by the optical sensor 50 is 1Y, 1M, 1C, 1K. The registration control unit 54 measures the time from when the resist patterns 1Y, 1M, and 1C are detected until the resist pattern 1K is detected. From the measured time, the resist patterns 1Y, 1M, and 1C and the resist pattern are measured. An interval from 1Y is calculated, and a difference between the calculated value and a reference value stored in advance is calculated. Then, correction data of the ejection timing of the recording head 32 for correcting this difference is created, and the ejection timing of the recording head 32 is corrected based on this correction data. Then, the process proceeds to step 106.

  In step 106, the cleaning blade 48 is separated from the conveyance belt 28 and the peeling plate 40 is brought into contact with the conveyance belt 28. Then, the process proceeds to step 108.

  In step 108, the recording head 32 ejects ink droplets onto the paper P based on the image data. At this time, ink droplets are ejected at the ejection timing corrected in step 104, thereby suppressing color misregistration. Then, the process proceeds to step 110.

  In step 110, the peeling plate 40 is separated from the transport belt 28 and the process proceeds to step 112. In step 112, it is determined whether or not the print job is completed. If the determination is affirmative, the process proceeds to step 114. If the determination is negative, the process proceeds to step 102 and steps 102 to 112 are repeated and executed.

  In step 114, the recording head array 30 is raised and the maintenance unit 34 is moved between the recording head array 30 and the conveyor belt 28. Then, the processing routine ends.

  As described above, in the present embodiment, since the resist patterns 1Y, 1M, 1C, and 1K are formed using the ink ejected in the dummy jet, the ink consumption can be suppressed. Further, since the dummy jet and the resist pattern are simultaneously formed, the time required for the dummy jet and the resist control can be shortened, and the print output throughput can be improved.

  Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment, and description is abbreviate | omitted.

  In the first embodiment, the optical sensors 50 are disposed at both ends in the width direction of the conveyor belt 28 to detect both ends of the resist patterns 1Y, 1M, 1C, and 1K, and the registration shift amount on both sides in the width direction is detected. Accordingly, the ejection timing of the recording head 32 is corrected. On the other hand, in the present embodiment, as shown in FIG. 8, the optical sensor 50 is disposed at the center in the width direction of the conveyor belt 28 to detect the resist patterns 11Y, 11M, 11C, and 11K, and the center in the width direction. The ejection timing of the recording head 32 is corrected according to the registration misregistration amount.

  Here, the registration patterns 11Y, 11M, 11C, and 11K are about 1/5 the length of the registration patterns 1Y, 1M, 1C, and 1K of the first embodiment, and are connected in the width direction and arranged in the transport direction. Are arranged at intervals.

  Here, the resist patterns 11Y, 11M, 11C, and 11K are arranged in the order of 11K, 11C, 11K, 11M, 11K, and 11Y from the upstream side in the transport direction in the detection range of the optical sensor 50, and ink of K color. The discharge amount of is increasing. On the other hand, outside the detection range of the optical sensor 50, 11K, 11C, 11Y, 11M or 11C, 11K, 11M, 11Y are arranged in the order from the upstream side in the transport direction, and Y, M, C, K colors The ratio of the ink discharge amount is uniform. As a result, the difference in ink discharge amount during the dummy jet between the recording head 32 serving as a reference for registration control and the other recording heads 32 can be suppressed, and the difference in discharge performance can be suppressed. Further, the difference in ink consumption can be suppressed.

  Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st, 2nd embodiment, and description is abbreviate | omitted.

  As shown in FIG. 9, in this embodiment, a pair of optical sensors 52 and 53 are disposed at both ends in the width direction of the conveyor belt 28. Further, outside the detection range of the optical sensors 52 and 53, the registration patterns 11Y, 11M, 11C, and 11K having a length about 1/5 of the registration patterns 1Y, 1M, 1C, and 1K of the first embodiment are They are connected in the direction and arranged in the transport direction A with an interval.

  Further, the resist patterns 111Y, 111M, 111C, and 111K are arranged in the order of 111K, 111C, 111K, 111M, 111K, and 111Y from the upstream side in the transport direction A in the detection range of the optical sensors 52 and 53. The discharge amount of color ink is increased. On the other hand, outside the detection range of the optical sensors 52, 53, they are arranged in the order of 11K, 11C, 11Y, 11M or 11C, 11K, 11M, 11Y from the upstream side in the transport direction A, and Y, M, The ratios of the C and K ink discharge amounts are uniform. Thereby, a difference in ejection performance among the plurality of recording heads 32 can be suppressed.

  Here, the resist patterns 111Y, 111M, 111C, and 111K are V-shaped when viewed from the downstream side in the transport direction. The optical sensors 52 and 53 are arranged in parallel to the sides of the resist patterns 111Y, 111M, 111C, and 111K. Therefore, as shown in FIG. 10A, when there is no positional deviation in the width direction of the resist patterns 111Y, 111M, 111C, and 111K, the resist patterns 111Y, 111M, 111C, and 111K are detected by the optical sensors 52 and 53. Are detected simultaneously. On the other hand, as shown in FIG. 10B, when there are misalignments in the width direction of the resist patterns 111Y, 111M, 111C, 111K, the resist patterns 111Y, 111M, 111C, There is a difference in the time at which 111K is detected.

  The registration control unit 54 calculates the amount of registration shift in the width direction based on the time difference when the detection signals are output from the optical sensors 52 and 53, and corrects the registration in the width direction. The lateral registration correction includes a method of shifting image data, a method of controlling the ejection position in the width direction from the recording head array 30, and a method of adjusting the position of the recording head array 30 in the width direction.

  Also, by providing a plurality of resist patterns in the width direction, it is possible to average a plurality of deviation detection results and reduce errors. Further, by detecting a difference between two points separated in the width direction, it is possible to detect a tilt deviation. As a method of detecting the tilt deviation, there are a method of changing ejection timing in the width direction, a method of shifting image data, and a method of adjusting the tilt of the recording head array 30.

  Next, a fourth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st thru | or 3rd embodiment, and description is abbreviate | omitted.

  As shown in FIG. 11, as in the first embodiment, optical sensors 50 are disposed at both ends in the width direction of the conveyor belt 28, and as in the second embodiment, the registration patterns 11Y, 11M, 11C, and 11K are They are connected in the width direction and arranged in the transport direction A with an interval.

  Here, the resist patterns 11Y, 11M, 11C, and 11K are arranged in the order of 11Y, 11C, 11K, and 11M, or 11C, 11K, 11M, and 11Y from the upstream side in the transport direction A outside the detection range of the optical sensor 50. The ratios of Y, M, C, and K ink discharge amounts are even.

  On the other hand, in the detection range of the optical sensor 50, after being arranged in the order of 11K, 11C, 11K, 11M, 11K, 11Y from the upstream side in the transport direction A, 11C, 11C, 11M, 11M, 11Y, They are arranged in the order of 11Y, and the ratios of Y, M, C, and K ink discharge amounts are uniform.

  As a result, the ratio of the ink discharge amount at the time of the dummy jet of the plurality of recording heads 32 becomes uniform, so that the difference in the discharge performance among the plurality of recording heads 32 can be suppressed.

  In the first to fourth embodiments, the present invention has been described by taking an inkjet recording apparatus as an example. However, the present invention is not limited to an inkjet recording apparatus, and the display is performed by discharging colored ink onto a polymer film. The present invention can be applied to a general liquid droplet ejection apparatus for various industrial uses such as production of a color filter for liquid crystal and formation of an EL display panel by discharging an organic EL solution onto a substrate.

  In addition, the “recording medium” that is a target of image recording in the droplet discharge device of the present invention includes a wide range of objects as long as the droplet discharge head discharges droplets. Accordingly, the recording medium includes recording paper, an OHP sheet, and the like, but also includes, for example, a polymer film.

  Furthermore, in the first to third embodiments, the present invention has been described by taking as an example a configuration in which a plurality of inkjet recording heads shorter than the width of the paper P are arranged in the width direction of the paper P as a unit. For example, the present invention can be applied to a configuration in which an inkjet recording head having a length shorter than the width of the paper P is moved in the width direction of the paper P.

1 is a side view illustrating an outline of an ink jet recording apparatus according to a first embodiment of the present invention. 1 is a side view illustrating an outline of an ink jet recording apparatus according to a first embodiment of the present invention. FIG. 2 is a side view illustrating an outline of a printing unit of the ink jet recording apparatus according to the first embodiment of the present invention. 1 is a block diagram showing a configuration of an electric system of an ink jet recording apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a printing unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 2 is a diagram showing a resist pattern formed on a transport belt in the ink jet recording apparatus according to the first embodiment of the present invention. 3 is a flowchart for explaining a method of performing a registration control and a dummy jet in the ink jet recording apparatus according to the first embodiment of the present invention. It is a figure which shows the resist pattern formed on the conveyance belt in the inkjet recording device of 2nd Embodiment of this invention. It is a figure which shows the resist pattern formed on the conveyance belt in the inkjet recording device of 3rd Embodiment of this invention. (A) and (B) are views showing a state in which a resist pattern formed on a conveyance belt passes through a detection range of a sensor in an ink jet recording apparatus according to a third embodiment of the present invention. It is a figure which shows the resist pattern formed on the conveyance belt in the inkjet recording device of 4th Embodiment of this invention.

Explanation of symbols

1Y resist pattern (test pattern)
1M resist pattern (test pattern)
1C resist pattern (test pattern)
1K resist pattern (test pattern)
11Y resist pattern (test pattern)
11M resist pattern (test pattern)
11C resist pattern (test pattern)
11K resist pattern (test pattern)
12 Inkjet recording device (droplet ejection device)
28 Conveying belt (conveying means)
32 Inkjet recording head (droplet ejection head)
50 sensor (pattern reading means)
52 Optical sensor (pattern reading means)
53 Optical sensor (pattern reading means)
54 Registration Control Unit (Position Correction Unit)
111Y resist pattern (test pattern)
111M resist pattern (test pattern)
111C resist pattern (test pattern)
111K resist pattern (test pattern)
P paper (recording medium)

Claims (3)

Conveying means for holding and conveying the recording medium;
A plurality of droplets are ejected on the recording medium conveyed by the conveying means based on image data to record an image, and a droplet is ejected on the conveying means based on test pattern data to form a test pattern. A droplet discharge head of
Pattern reading means for reading a test pattern formed on the conveying means;
A positional deviation correction unit that corrects a deviation of an image recording position by each droplet ejection head based on a reading result of the pattern reading unit;
The droplet discharge apparatus, wherein the droplet discharge head discharges a droplet for recovering the discharge performance of a nozzle to the transport unit based on the test pattern data.   At least outside the reading range of the reading unit, the droplet discharge ratios of all the nozzles in each droplet discharge head are uniform, and the droplet discharge ratios of the plurality of droplet discharge heads are uniform. The droplet discharge apparatus according to claim 1, wherein the test pattern is configured.   The test pattern is configured such that the droplet discharge ratios of all the nozzles are uniform in each droplet discharge head, and the droplet discharge ratios of the plurality of droplet discharge heads are uniform. The droplet discharge device according to claim 1.

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