JP5869290B2 - Inkjet recording apparatus and recording method - Google Patents

Description

  The present invention relates to an ink jet recording apparatus and a recording method.

  2. Description of the Related Art Conventionally, ink jet recording apparatuses that perform recording on a recording medium by discharging ink droplets from nozzles provided in a recording head are known. Among inkjet recording apparatuses, an inkjet recording apparatus for outdoor sign use generally uses a recording head that uses a piezoelectric element as a recording element, and uses an ink containing an organic solvent as a main solvent.

  When recording is performed using such an ink jet recording apparatus, depending on the recording conditions, ejection may become unstable and ink may be ejected by deflecting from the nozzles, or even ink may not be ejected. In particular, when recording an image with a light color as a whole, or using an inkjet recording apparatus that performs recording by a so-called multi-pass recording method in which a recording head scans the same recording area of a recording medium a plurality of times to perform recording. In the case of printing with a large number of passes, the time from the ejection to the next ejection (hereinafter referred to as intermittent time) becomes longer. In such cases, the ejection tends to become unstable due to evaporation and thickening of the volatile components of the ink in the nozzles during the intermittent period. Various techniques have been disclosed as techniques for avoiding such discharge instability. For example, Patent Document 1 uses an inkjet recording apparatus having a recording head having a plurality of nozzle rows, counts the exposure time of the nozzles to the atmosphere, and sets the ejection timing of the plurality of nozzle rows according to the exposure time. A technique for adjusting is disclosed.

JP 2007-76238 A

  However, as a result of intensive studies by the present inventors, using the technique disclosed in Patent Document 1, the ejection stability is improved under specific recording conditions, but the effect is not achieved under other specific recording conditions. It turned out to be sufficient. This is because the intermittent time is not a unit of a nozzle row or a predetermined column unit of a nozzle row, but is often different for each nozzle depending on the image to be recorded.

Accordingly, the present invention has been made to solve the problem that the ejection becomes unstable due to the prolonged intermittent time, and an object of the present invention is to provide an ink jet recording apparatus that ejects stably regardless of the image to be recorded. And
It is another object of the present invention to provide a recording method for stably discharging regardless of an image to be recorded using an ink jet recording apparatus.

In order to solve the above-described problems, the present invention is directed to the same recording area of a recording medium in which image data is input and ink is ejected from a plurality of nozzles provided in the recording head based on the recording data generated from the image data. An ink jet recording apparatus that performs recording a plurality of times and further includes a cleaning unit that cleans the recording head , wherein nozzles used for each of the plurality of scans are the plurality of scans. Predetermined from among the nozzles, the ink jet recording apparatus forms a recording dot at a recording position corresponding to the image data, and a measuring unit that measures the time after ejection of the plurality of nozzles for each nozzle. a nozzle extracting means extracts from the plurality of nozzles of the nozzle can be, for nozzles each of said nozzles extracting means has extracted, The time until one nozzle is recorded from the discharge of the last to the next of said recording position, a calculation means for calculating based on the measurement values of the measuring means, said calculation means of the nozzle where the nozzle extracting means has extracted Selection means for selecting a nozzle to be ejected so as to minimize the calculated calculation time, and recording data generation for generating the recording data from the image data to be recorded at the recording position using the nozzle selected by the selection means It has at least a means.

Another embodiment of the present invention for solving the above-described problem is a recording medium in which image data is input and ink is ejected from a plurality of nozzles provided in a recording head based on recording data generated from the image data. there lines recorded by scanning a plurality of times for the same recording area, yet the a recording method for an ink jet recording apparatus having a cleaning unit for cleaning the recording head, the plurality of scans of each of the scan A step of predetermining nozzles to be used from among the plurality of nozzles, a measurement step of measuring the time after ejection of the plurality of nozzles for each nozzle, and a recording dot at a recording position corresponding to the image data a nozzle extracting step of extracting a nozzle capable of forming from the plurality of nozzles, with respect to the nozzle respectively extracted by the nozzle extracting step, the same nozzle Calculation but the time from the ejection of the last to be recorded on the next of said recording position, a calculating step of calculating, based on the measurement value measured by the measuring step, in the calculation step of the nozzle extracted by the nozzle extracting step A selection step of selecting a nozzle to be ejected so as to minimize the calculated time, and a recording data generation step of generating the recording data from the image data so as to record at the recording position using the nozzle selected in the selection step And at least a recording step of recording based on the recording data generated in the recording data generation step.

  According to the present invention, it is possible to provide an ink jet recording apparatus that discharges stably regardless of an image to be recorded. Further, it is possible to provide a recording method that stably discharges regardless of an image to be recorded using an ink jet recording apparatus.

1 is a front view schematically showing a schematic configuration of an ink jet recording apparatus according to a preferred embodiment of the present invention. 1 is a block diagram schematically showing a schematic configuration of an ink jet recording apparatus according to a preferred embodiment of the present invention. It is a flowchart which shows preferable embodiment of the recording method of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a front view schematically showing a schematic configuration of an ink jet recording apparatus according to a preferred embodiment of the present invention.
As shown in FIG. 1, the inkjet recording apparatus 1 of the present embodiment arranges a recording medium 50 horizontally and conveys it in the depth direction of the paper surface of FIG. 1, and responds to recording data on the surface of the recording medium 50 by an inkjet method. Record images and text.

  The inkjet recording apparatus 1 includes a transport unit 40 that transports the recording medium 50 and a recording unit 41 that records on the recording medium 50. The recording head 9 includes a recording head 9 that performs reciprocating scanning in a direction orthogonal to the conveyance direction of the recording medium 50, and a cleaning unit 10 that cleans the recording head 9. The inkjet recording apparatus 1 includes a control unit (not shown) that controls the entire apparatus including reception of recording data and control of recording operations.

  The transport unit 40 includes a plurality of pinch rollers 3 that are rotated about a horizontal axis along the paper surface by a motor 5 on the substantially flat platen 2 that extends in the depth direction of the paper surface of FIG. A plurality of grid rollers 4 supported by these pinch rollers 3 so as to be rotatable about a rotation axis parallel to the rotation axis of the pinch roller 3 are arranged in the depth direction of the drawing. These grid rollers 4 are aligned above the platen 2 in a horizontal plane extending in the depth direction in FIG. 1 to form a conveyance path for the recording medium 50.

  The recording unit 41 includes a carriage rail 7 that extends in a direction perpendicular to the conveyance direction of the recording medium 50 above the conveyance unit 40 and the cleaning unit 10, and a recording head that is movable along the carriage rail 7. Unit 8 is provided. In addition, a motor 6 that reciprocates the recording head unit 8 on the carriage rail 7 so as to be capable of position control and speed control is provided. Furthermore, a detachable ink cartridge 17 that supplies recording ink to the recording head unit 8 is provided.

  In the present embodiment, the ink cartridge 17 is provided with a plurality of colors of ink for performing color recording, and the recording head unit 8 is provided for each color via a plurality of ink tubes 16 serving as piping (ink flow paths). Can be supplied.

  The recording head unit 8 is provided with a plurality of recording heads 9 on the lower surface side in accordance with the ink color and recording range, and the ink supplied from the ink tube 16 is distributed to the recording heads 9 that perform recording of the same color. Supplied. Further, the recording head unit 8 is provided with a cooling fan 18 for keeping the temperature of each recording head 9 in an appropriate temperature range.

  Although details of the recording head 9 are not shown, an ink chamber for supplying ink to each nozzle and an ejection mechanism using a piezoelectric element are provided. The recording head 9 is configured to be able to perform an idle driving operation in which the ink is ejected and the ink meniscus of the nozzle is finely oscillated by an ejection mechanism using the piezoelectric element. Further, the nozzles can be provided with an appropriate number and arrangement pitch according to the configuration of the ejection mechanism, the recording pixel pitch, and the like. For example, a large number of nozzles such as 256 can be arranged. The recording head 9 of this embodiment uses a piezoelectric element as the recording element, but may be a recording head using a heater as the recording element. However, compared with an ink jet recording apparatus using a recording head using a heater as a recording element, an ink jet recording apparatus using a recording head using a piezoelectric element as the recording element has a greater effect. In general, it is considered that the piezoelectric element causes the ink to be ejected with a smaller energy applied to the ink than the heater.

  The position control and speed control of the motor 6 are performed according to the control signal of the control unit, and the motor 6 moves the recording head unit 8 back on the recording medium 50 at a predetermined speed during the recording operation. Further, the motor 6 can move the recording head unit 8 to a predetermined cleaning position in the cleaning unit 10 during the cleaning operation.

  In this embodiment, the cleaning unit 10 includes a suction cleaning unit 14A that cleans the recording head 9 by sucking the ink in the recording head 9 from the nozzles to the outside, and the recording head 9 by wiping the recording head surface. It consists of a wipe part 14B to be cleaned. The cleaning unit 10 is arranged on the moving path of the recording head unit 8 on the side of the transport unit 40 and below the recording unit 41 in the order of the wipe unit 14B and the suction cleaning unit 14A from the transport unit 40 side. In the present embodiment, the upper positions of the suction cleaning unit 14A and the wipe unit 14B are predetermined cleaning positions.

  The schematic configuration of the suction cleaning unit 14A includes a cap 11, a cap drive unit (not shown), a suction pump 12, a pump drive unit (not shown), an air release valve (not shown), and an air release valve drive unit (not shown). Become.

  Among these, at least the cap 11 is provided for each recording head 9. However, the cap drive unit, the suction pump 12, the air release valve, and the air release valve drive unit may be configured to be provided for each of the plurality of caps 11 when each operation can be made common for each recording head 9. .

  The cap drive unit moves up and down to selectively switch the position of the cap 11 in the vertical direction, and includes, for example, appropriate mechanical, electromagnetic, and fluid lifting means. Therefore, the cap drive unit moves the cap 11 up and down in the vertical direction with respect to the recording head unit 8 which is moved on the carriage rail 7 by the motor 6 and positioned above the suction cleaning unit 14A, and the cap 11 performs recording. The state where the head surface is sealed and the state where the sealing is released can be switched.

  The suction pump 12 is for sucking contents such as air and ink in the suction space and discharging them to the outside of the suction space, and an appropriately configured fluid pump such as a rotary pump can be adopted. In this embodiment, the suction amount can be varied by the pump drive unit. Further, the suction amount of the suction pump 12 may be changed in multiple stages as necessary. The suction pump 12 has a suction port connected to the suction pipe and a discharge port connected to the discharge pipe. The other end of the discharge pipe is connected to the waste liquid bottle 15.

  In the suction cleaning unit 14A, the cap driving unit, the air release valve driving unit, and the pump driving unit are electrically connected to a cleaning control unit (not shown), and their operations are controlled by control signals from the cleaning control unit. It has become so.

  The wipe unit 14B may have any configuration as long as it performs a known wiping process. For example, it is possible to employ a configuration in which the recording head surface is wiped by relatively moving a wiping blade containing a wiping liquid on the recording head surface of the recording head 9 moved above the wiping portion 14B.

FIG. 2 is a block diagram schematically showing a schematic configuration of an ink jet recording apparatus according to a preferred embodiment of the present invention.
In FIG. 2, reference numeral 20 denotes a control unit. The control unit 20 includes a CPU 25 that executes processing operations such as calculation, control, discrimination, and setting, a ROM 26 that stores a control program to be executed by the CPU 25, and a recording data A RAM 27 and the like used as a work area for processing by the buffer and CPU 25 are provided.

  In the ink jet recording apparatus 1 of the present embodiment, the control unit 20 includes a timer 13 and measures the time after ejection of each nozzle of the recording head 9 for each nozzle. The control unit 20 also extracts nozzles that can form recording dots at recording positions corresponding to image data input from an external device via the input unit 23. For example, when ink is ejected to a predetermined recording position while recording in four passes, nozzle A that can be recorded in the first pass at that recording position, nozzle B that can be recorded in the second pass, 3 The nozzle C that can be recorded in the second pass and the nozzle D that can be recorded in the fourth pass are extracted. Then, the control unit 20 calculates an intermittent time that is an elapsed time when the nozzle A is discharged from the previous discharge to the recording position based on the measurement value of the timer 13. Similarly, the control unit 20 calculates the intermittent time for each of the nozzles B to D. And the control part 20 selects the nozzle with which the intermittent time of each of the nozzle A to the nozzle D becomes the minimum. For example, when the nozzle having the minimum intermittent time is nozzle A, nozzle A is selected. Then, the control unit 20 generates print data so that the nozzle ejected to the print position is the nozzle A. In order to eject ink from the recording head 9 based on the generated recording data, the control unit 20 controls driving of the recording head driving unit 22. Under this control, the recording head drive unit 22 drives the recording head 9 to eject ink.

  In the inkjet recording apparatus 1 of the present embodiment, data related to the number of passes in the multi-pass recording method is stored in the EEPROM 28 as a nonvolatile memory. The number of passes can be arbitrarily set by the user via the operation panel 24.

Next, the ink preferably used in the ink jet recording apparatus of the present invention will be described.
The ink preferably used in the ink jet recording apparatus of the present invention is an ink containing a volatile component. This is because ink that does not contain a volatile component often does not have a bad intermittent discharge property even when the intermittent time is long, and in many cases such problems do not occur in the first place, and the effect of the present invention may be weak. . Further, the ink that is more preferably used in the ink jet recording apparatus of the present invention is a so-called solvent ink containing an organic solvent as a main solvent. This is because the effects of the present invention are particularly remarkable when this ink is used.

Next, the recording method of the present invention will be described.
FIG. 3 is a flowchart showing a preferred embodiment of the recording method of the present invention.
The ink jet recording apparatus 1 used in this embodiment is a multipass ink jet recording apparatus that performs recording by scanning the recording head 9 a plurality of times on the same recording area of the recording medium 50.

  When the inkjet recording apparatus 1 inputs image data from a host computer via the input unit 23, the control unit 20 generates recording data from the image data and records it. First, in step S <b> 110, the control unit 20 uses the timer 13 to measure the time after ejection for a plurality of nozzles provided in the recording head 9 for each nozzle.

  Next, in step S120, the control unit 20 extracts a nozzle capable of forming a recording dot at a recording position corresponding to the image data. This embodiment is a recording method in which ink is ejected to a predetermined recording position while recording in four passes. In step S120, the nozzle A that can be recorded in the first pass at the recording position, the nozzle B that can be recorded in the second pass, the nozzle C that can be recorded in the third pass, the fourth pass. The nozzle D that can be recorded is extracted. In this embodiment, one nozzle that can be recorded at the recording position is extracted one by one in each pass, but it is also possible to use an ink jet recording apparatus configured to extract a plurality of nozzles in each pass. In addition, for example, nozzles that can be recorded one nozzle at a time in the first pass and the third pass are extracted, but nozzles that can be recorded in a relationship with another algorithm in the second pass and the fourth pass. It is also possible to use a recording device in which no is extracted.

Next, in step S <b> 130, the control unit 20 calculates, based on the measurement value of the timer 13, an intermittent time that is an elapsed time when the nozzle A to the nozzle D are discharged from the previous discharge to the recording position.
Next, in step S140, the control unit 20 selects a nozzle that minimizes the intermittent time of each of the nozzles A to D. In the present embodiment, the nozzle having the minimum intermittent time is referred to as nozzle A. In step S140, the control unit 20 selects the nozzle A.

Next, in step S150, the control unit 20 generates print data so that the nozzle ejected to the print position is the nozzle A.
Next, in step S160, the inkjet recording apparatus 1 performs recording based on the recording data generated in step S150, thereby ending the processing of the recording method of the present embodiment.

  The ink jet recording apparatus and the recording method of the present invention can be used for a general ink jet recording apparatus.

DESCRIPTION OF SYMBOLS 1 Recording device 9 Recording head 20 Control part

Claims (6)

Inputting image data based on the recording data generated from the image data, ejects ink from a plurality of nozzles provided in the recording head, the line physician recording by scanning a plurality of times for the same recording area of the recording medium And an inkjet recording apparatus further comprising a cleaning unit for cleaning the recording head ,
A nozzle used for each of the plurality of scans is determined in advance from the plurality of nozzles,
The ink jet recording apparatus comprises:
Measuring means for measuring the time since ejection of the plurality of nozzles for each nozzle;
Nozzle extracting means for extracting , from the plurality of nozzles, nozzles capable of forming recording dots at recording positions corresponding to the image data;
For each of the nozzles extracted by the nozzle extracting means, a calculating means for calculating the time until the same nozzle records from the previous ejection to the next recording position based on the measurement value of the measuring means;
Selecting means for selecting a nozzle to be discharged so that the calculation time calculated by the calculating means is minimized among the nozzles extracted by the nozzle extracting means;
An inkjet recording apparatus comprising at least recording data generating means for generating the recording data from the image data so as to record at the recording position using the nozzle selected by the selecting means. Before SL nozzle extracting unit the image corresponding to the data recording position in the first first capable of forming recording dots in the scanning of the nozzle and the second capable of forming recording dots with a second scan The inkjet recording apparatus according to claim 1, wherein both of the nozzles are extracted.   The inkjet recording apparatus according to claim 1, wherein the ink contains a volatile component.   The ink jet recording apparatus according to claim 1, wherein the ink contains an organic solvent as a main solvent.   The ink jet recording apparatus according to claim 1, wherein the recording head uses a piezoelectric element as a recording element. Inputting image data based on the recording data generated from the image data, ejects ink from a plurality of nozzles provided in the recording head, the line physician recording by scanning a plurality of times for the same recording area of the recording medium And a recording method of an ink jet recording apparatus further comprising a cleaning unit for cleaning the recording head ,
A step in which a nozzle to be used for each of the plurality of scans is determined in advance from the plurality of nozzles;
A measuring step of measuring the time since ejection of the plurality of nozzles for each nozzle;
A nozzle extracting step of extracting a nozzle capable of forming a recording dot at a recording position corresponding to the image data from the plurality of nozzles ;
For each of the nozzles extracted in the nozzle extraction step, a calculation step for calculating the time until the same nozzle records from the previous ejection to the next recording position based on the measurement value of the measuring means ,
A selection step of selecting a nozzle to be discharged so that the calculation time calculated in the calculation step is minimized among the nozzles extracted in the nozzle extraction step;
A recording data generation step of generating the recording data from the image data so as to record at the recording position using the nozzle selected in the selection step;
A recording method comprising at least a recording step of recording based on the recording data generated in the recording data generation step.

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