JP2009056738A - Ink-jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet recorder which can inspect a recorded state on the same conditions even for a recording medium having different thickness and a surface condition. <P>SOLUTION: An ink-jet recording head 1 moves to the scanning direction X with a drive belt 3 and performs recording operation to a recording medium 6. A pedestal 10 on which the ink-jet recording head 1 is laid is provided such that it allows forward and backward movement action to the recording medium 6 and adjusted so that it may have a predetermined interval according to the thickness and surface shape of the recording medium 6. A push member 26 is disposed on an inspecting sheet 21 of an inspection mechanism 20 provided outside a recording region, and the push member 26 is controlled by an air cylinder so that it moves forwardly and backwardly to the head 1. When the push member 26 is positioned in an inspection position, the inspecting sheet 21 approaches a nozzle surface of the head, so that a predetermined pattern can be recorded on the inspection sheet on the same conditions without being influenced by wind or the like. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs recording by moving an ink jet recording head that discharges ink from nozzles toward a recording medium in the main scanning direction and transporting the recording medium in the sub scanning direction. is there.

  The ink jet recording method performs printing and image recording by ejecting minute ink from a nozzle of an ink jet recording head to a recording medium, and can perform a recording operation in a state separated from the recording medium. It can be recorded on recording media and articles made of materials, and is used in a wide range of applications.

  As a recording operation using inkjet recording, a serial type in which the recording head is moved in the main scanning direction to perform a recording operation on the recording medium along the scanning line, and the recording medium is conveyed in the sub-scanning direction to sequentially record, A line type in which a plurality of recording heads are arranged in a line in the main scanning direction and recording is performed while the recording medium is conveyed in the sub scanning direction has been developed according to the application.

In such an ink jet recording apparatus, clogging is likely to occur in nozzles that eject ink, and when such clogging occurs, troubles such as recording unevenness occur due to ejection abnormalities. For this reason, the nozzle surface cleaning operation and the discharge recovery operation are performed when it is determined that the recording operation is normally performed and determined to be abnormal. For example, Patent Document 1 describes that a predetermined pattern is recorded on a recording material dedicated to a monitor by a recording head, and the recorded pattern is read by a sensor to determine abnormality such as non-ejection of the recording head. ing. Japanese Patent Application Laid-Open No. 2004-228561 describes that the ejection state of a plurality of nozzles of a recording head is inspected in synchronization with a recording operation by a nozzle inspection unit including a light emitting element and a light receiving element. Japanese Patent Application Laid-Open No. H10-228561 describes that an ink droplet ejected from a nozzle is detected by an ink droplet detection device including a light emitting unit and a light receiving unit.
JP-A-5-301426 JP 2003-54006 A JP 2007-15194 A

  As described above, the ink jet recording apparatus has an advantage that recording operation can be performed on recording media of various materials. For example, when the recording operation is performed on a fabric such as a woven fabric, a knitted fabric, or a non-woven fabric. In addition, the thickness is often different depending on the fabric, and the surface state may be fuzzy or uneven patterns may be formed. It is necessary to perform a recording operation in accordance with the characteristics of such a recording medium. In addition to fabrics, recording media made of materials such as plastic, metal, or ceramic have different thicknesses or various surface treatments, and these recording media can also perform recording operations according to their characteristics. Need to do. For this reason, even when inspecting an ink ejection abnormality as described in the above-mentioned prior art, it must be possible to inspect whether a normal recording operation is performed in accordance with the characteristics of the recording medium.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording apparatus that can inspect a recording state under the same conditions for recording media having different thicknesses and surface conditions.

  An ink jet recording apparatus according to the present invention includes a recording mechanism that moves an ink jet recording head that discharges ink from a nozzle toward a recording medium in a main scanning direction, and a conveyance mechanism that conveys the recording medium in a sub scanning direction. In the ink jet recording apparatus, the main scanning is performed by an interval adjusting unit that adjusts an interval between the recording surface of the recording medium and the nozzle surface of the ink jet recording head by moving the recording mechanism relative to the transport mechanism. A recording state inspection means for inspecting a recording state based on a predetermined pattern which is disposed outside the recording range of the direction and is recorded on the inspection surface facing the nozzle surface, and the inspection surface is brought close to the nozzle surface And positioning means for positioning at an inspection position or a retracted position separated from the nozzle surface. Further, the positioning means is provided so as to be interlocked with the movement of the recording mechanism by the interval adjusting means.

  By having the above-described configuration, the thickness of the recording medium is adjusted by the interval adjusting means that adjusts the interval between the recording surface of the recording medium and the nozzle surface of the inkjet recording head by moving the recording mechanism relative to the transport mechanism. It is possible to perform the recording operation by always adjusting the optimum interval according to the surface state.

  Further, a recording state inspection means for inspecting the recording state based on a predetermined pattern recorded on the inspection surface facing the nozzle surface is disposed outside the recording range in the main scanning direction, and the inspection surface is brought close to the nozzle surface. Since positioning means is provided for positioning at the inspection position or the retreat position away from the nozzle surface, the inspection surface of the recording state inspection means is set to the inspection position close to the nozzle surface by the positioning means when inspecting the recording state. Thus, the inspection can be performed under the same conditions, and the inspection can be accurately performed even when the thickness or surface state of the recording medium changes. In addition, when the recording state is not inspected, if the inspection surface of the recording state inspection unit is set to the retracted position separated from the nozzle surface by the positioning unit, the minute ink mist generated accompanying ink ejection may cause It is possible to avoid contamination of the inspection surface.

  In addition, when performing a recording operation on a recording medium having various surface states, even if the interval between the recording medium surface and the nozzle surface is adjusted, if the surface of the recording medium is fuzzy or has an uneven pattern, the nozzle surface The ink may inadvertently adhere to the inspection surface and get dirty due to the fluff, etc., in the present invention, but in the present invention, the inspection surface is set at a retracted position separated from the nozzle surface by the positioning means. Therefore, it is possible to prevent inadvertent contamination of the inspection surface regardless of the surface condition of the recording medium and to perform inspection more accurately. Even if the recording medium such as plastic, metal, or ceramic other than cloth is used, even if the thickness or surface condition changes, the positioning of the inspection surface will not be shifted. Can be inspected.

  Further, by providing the positioning means in conjunction with the movement of the recording mechanism by the interval adjusting means, the positioning accuracy of the inspection position of the inspection surface with respect to the nozzle surface can always be kept constant.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus. The inkjet recording head 1 is mounted and fixed on a carriage 2, and the carriage 2 is fixed to an endless drive belt 3. The driving belt 3 is stretched between the driving pulley 4 and the driven pulley 5, so that the conveying belt 3 is moved by the rotational driving of the driving pulley 4, and the carriage 2 reciprocates in the main scanning directions X 1 and X 2. Become.

  The sheet-like recording medium 6 is fed from the feed roll 7 and recorded so as to be wound around the take-up roll 8, and the recording medium 6 is transported by the transport roll 9 so as to face the ink jet recording head 1. A path is set and conveyed in the sub-scanning direction Y.

  The surface of the ink jet recording head 1 facing the recording medium 6 is a nozzle surface on which a plurality of nozzles for ejecting ink are formed. Ink is supplied into the head from an ink supply device (not shown) and connected to the nozzles. The ink is introduced into the ink flow path, and pressure fluctuation is applied to the ink by a pressure fluctuation means such as a piezoelectric element provided with the ink flow path, so that the ink is ejected from the nozzle. As such an ink jet recording head, a known one can be used.

  When a recording operation is performed on the recording medium 6, the inkjet recording head is driven and controlled based on a recording signal while moving the inkjet recording head in the main scanning direction, and ink is ejected along the scanning line to perform line recording. When the scanning line recording is completed, the recording medium is transported in the sub-scanning direction, and transport control is performed so that the next scanning line faces the ink jet recording head. In this way, image recording is performed on the surface of the recording medium 6 by alternately repeating recording control in the main scanning direction and conveyance control in the sub-scanning direction.

  The drive pulley 4 and the driven pulley 5 that stretch the drive belt 3 are attached to a frame (not shown) and mounted and fixed on the upper surface of the base 10 via the frame, and both ends of the base 10 are paired with each other. It is supported by the support frame 11. A rail portion (not shown) is formed on the upper surface of the support frame 11 toward the recording medium 6 on the joint surface between the base 10 and the support frame 11, and the lower surface of the base 10 is fitted to the rail portion. A matching notch is formed. Therefore, the base 10 is movably attached so as to move forward and backward with respect to the recording medium 6. A spacing adjustment screw 12 is threadedly engaged with and attached to the mounting portion 13 at the upper portion of the support frame 11, and a distal end portion of the spacing adjustment screw 12 is rotatably fixed to the mounting hole of the base 10. Therefore, the base 10 moves forward and backward with respect to the recording medium 6 by rotating the interval adjusting screw 12, and the interval between the recording medium 6 and the nozzle surface of the inkjet recording head 1 can be adjusted. When the base 10 is moved to adjust the interval, means for electrically controlling movement such as a motor may be used.

  FIG. 2 is an explanatory diagram for adjusting the distance between the recording medium 6 and the nozzle surface of the inkjet recording head 1. For the recording medium 6, various sheet materials are used, and those having a smooth surface such as a film sheet and synthetic leather, and those having a non-smooth surface such as fabric, knitted fabric, non-woven fabric, artificial leather, and natural leather are used. It is done. In the fabric, it is necessary to perform recording on various surface shapes such as a fuzzy one or a surface on which irregularities such as embroidery are formed. In addition, even for recording media made of various materials such as plastic, metal, or ceramic, even when the thickness or surface state of the recording medium changes variously, it is necessary to perform a normal recording operation accordingly.

  Therefore, as shown in FIG. 2A, for a recording medium having a relatively smooth surface shape, the distance between the recording medium 6 and the nozzle surface is set to a distance d (several millimeters). The adjustment screw 12 is adjusted. When the distance d is set to be large, the ink ejected with the nozzle surface being separated from the recording medium 6 is likely to be affected by the wind. Therefore, it is desirable to set the distance d to be small. In FIG. 2B, the surface of the recording medium 6 is fuzzy, and therefore the interval between the recording medium and the nozzle surface is adjusted so that the distance d is from the tip of the fuzzy hair tip. When the surface shape of the recording medium is not smooth in this way, the outermost surface is set as a virtual recording surface, but the fuzzy ends are not aligned at the same height, so the average height is used as a reference. The distance d must be set. Therefore, when the surface shape is not smooth, fluff and the like often adhere to the nozzle surface, which may adversely affect ink ejection from the nozzle.

  In order to inspect such an ink discharge abnormality, an inspection mechanism 20 as a recording state inspection unit is disposed outside the recording range in the main scanning direction. The inspection mechanism 20 is fixedly attached to an apparatus frame (not shown), and the ink jet recording head 1 is moved to a position facing the inspection mechanism 20 during a recording operation or at the start of recording to inspect the ink ejection state. When the ink ejection abnormality is determined in the inspection mechanism 20, the suction recovery operation is performed by moving to the ejection recovery mechanism (not shown) and capping the nozzle surface.

  The inspection mechanism 20 includes a strip-shaped inspection sheet 21 that receives ink ejected from the nozzles of the ink jet recording head, and the inspection sheet 21 is fed from a feed roll 22 and is recorded with a predetermined pattern for inspection. The conveyance path of the inspection sheet 21 is set so as to face the inkjet recording head 1 by the conveyance roll 24 and is conveyed in the sub-scanning direction Y. The predetermined pattern recorded on the inspection sheet 21 is conveyed to a position facing the image sensor 25 and read to determine whether there is an ink ejection abnormality.

  At the position of the inspection sheet 21 facing the ink jet recording head 1, a pressing member 26 is disposed on the opposite side of the ink jet recording head 1 as positioning means, and the contact surface of the pressing member 26 with the inspection sheet 21. Is formed so as to be flat and substantially parallel to the nozzle surface of the inkjet recording head 1.

  The pushing member 26 is fixedly attached to the upper end portion of the arm member 27, and an air cylinder is attached to the lower end portion of the arm member 27 as driving means. The air cylinder is attached and fixed to the base 10, and the pushing member 26 moves in conjunction with the inkjet recording head 1. By driving and controlling the air cylinder, the arm member 27 is moved to move the pushing member 26 forward and backward with respect to the ink jet recording head 1.

  FIG. 3 is an explanatory diagram relating to the advance / retreat operation of the push member 26. FIG. 3A shows a state in which the pushing member 26 is set at the retracted position, and the pushing member 26 is in close contact with the back surface of the inspection sheet 21 while being stretched between the transport rolls 24. Is set in the state. In this state, the interval between the inspection sheet 21 and the nozzle surface 1a of the ink jet recording head 1 is set to be large, and an interval at which the inspection sheet 21 is not soiled by fuzz attached to the nozzle surface 1a is provided. ing. Since the ink jet recording head 1 is separated from the inspection sheet 21, it is possible to prevent ink mist generated during ink ejection from adhering to the inspection sheet 21.

  In FIG. 3B, the air cylinder 30 is driven to move the arm member 27 to the ink jet recording head 1 side, so that the pushing member 26 is set at an inspection position approaching the nozzle surface 1a. In this state, the inspection member 21 is pushed by the pushing member 26 so as to be pulled toward the nozzle surface 1a, and the interval between the nozzle surface 1a and the inspection sheet 21 is reduced, and the recording medium described in FIG. 6 is set to an interval approximately equal to the distance d between the two. Therefore, the ink ejected toward the inspection sheet 21 can record a predetermined pattern without being affected by wind or the like, and it is possible to accurately determine an ink ejection abnormality.

  As described above, since the inspection sheet 21 of the inspection mechanism 20 can be positioned at the retracted position or the inspection position by the pushing member 26, when recording on a recording medium having a different thickness or surface shape, Even if the distance between the recording medium and the recording medium is adjusted, the positional relationship between the inspection sheet 21 and the inkjet recording head 1 does not change, and it is possible to determine ink ejection abnormality under the same conditions. That is, since the pushing member 26 is provided on the base 10 via the arm member 27, the pushing member is moved when the base 10 is moved to adjust the interval between the inkjet recording head 1 and the recording medium. 26 moves in conjunction with the ink jet recording head 1 and the positional relationship between the pushing member 26 and the ink jet recording head 1 does not change. Therefore, even when the base 10 is moved and the interval is adjusted, the inspection sheet can always be positioned at the same position with respect to the ink jet recording head 1, and an accurate recording state inspection can be performed.

  In addition, when the recording state is not inspected, the pressing member 26 is set at the retracted position so that the inspection sheet is separated from the nozzle surface, thereby preventing the inspection sheet from being inadvertently stained with ink. It is possible to record the predetermined pattern by setting the pushing member 26 at the inspection position only at the time of inspection and bringing the inspection sheet close to the ink jet recording head 1 to avoid the influence of wind or the like. It is possible to obtain a test result with less noise by ejecting ink onto a test sheet having no noise.

  When positioning the pushing member 26 at the inspection position, the inspection position may be set so that the distance between the inspection sheet and the nozzle surface is constant. Further, when the pushing member 26 is positioned at the retracted position, it may be set at a position separated from the inspection position by a predetermined distance, but the set position can be made variable according to the thickness or surface shape of the recording medium 6. Is also possible.

  When the inspection surface of the inspection sheet is moved to the retracted position, the entire inspection mechanism 20 may be moved. When the inspection surface is separated from the nozzle surface, the inspection surface is retracted to a position moved up and down with respect to the nozzle surface. You may make it do.

  FIG. 4 is a processing flow for inspecting the recording state of the ink jet recording head. First, it is checked whether an inspection recording signal is input during a recording operation or at the start of recording (S100). If an inspection recording signal is input, image data of a predetermined pattern is read (S101). Then, the inkjet recording head is moved and positioned to the inspection position facing the inspection mechanism 20 (S102).

  Next, the air cylinder is driven to move the pushing member 26 from the retracted position to the inspection position (S103), and the inspection sheet is set in a state of approaching the nozzle surface at a predetermined interval. Then, the inkjet recording head 1 is driven and controlled based on the image data of the predetermined pattern, and the predetermined pattern is recorded on the inspection sheet (S104). After the pattern recording is completed, the pushing member 26 is moved back to the retracted position (S105).

  Next, the inspection sheet is conveyed, the pattern recording portion is positioned at a position facing the image sensor, and the pattern recorded by the image sensor is read and analyzed (S106). For example, when a pattern as shown in FIG. 5 is recorded, ink is simultaneously ejected from a plurality of nozzles arranged in the vertical direction and recorded on the inspection sheet.

  When analyzing the recorded pattern, the captured image obtained by capturing the pattern with the image sensor is subjected to image processing to calculate the RGB value for each pixel, and the binary value of the captured image is calculated based on the calculated RGB value. The threshold for the digitization process is determined. Then, the captured image is binarized based on the threshold value, and items such as the area S of the recording pattern of each nozzle subjected to the binarization process, the length Lx in the X direction, and the length Ly in the Y direction are measured.

  Next, the measured value of each item is compared with a preset reference value to determine whether there is an ejection abnormality (S107). For example, when the measured value is out of the allowable range of the reference value, it is determined that a nozzle ejection abnormality has occurred. If it is within the allowable range, the recording operation is continued as it is (S108). If it is determined as abnormal, the inkjet recording head is moved to a position facing the ejection recovery mechanism (S109), and the nozzle of the inkjet recording head Capping is performed so as to cover the surface, and a recovery operation such as cleaning of the nozzle surface and suction of the nozzle is performed (S110). After completion of the recovery operation, the process returns to step S101, and the recording state is inspected again.

  As described above, only when inspecting the recording state, the pressing member is moved to the inspection position and positioned, and the predetermined pattern is recorded with the inspection sheet approaching the nozzle surface. Therefore, it is possible to accurately inspect even in the case of a recording medium having irregularities or fuzzy surfaces. Further, when there is a discharge abnormality, the recovery operation is performed immediately so as not to generate a recording failure as much as possible, and the recording operation can be performed with a good image quality even on a recording medium in which fuzz etc. easily adhere to the nozzle surface.

It is a schematic block diagram regarding an inkjet recording device. It is explanatory drawing regarding the space | interval adjustment between an inkjet recording head and a recording medium. It is explanatory drawing regarding the advance / retreat operation | movement of a pushing member. It is a processing flow for inspecting the recording state of an inkjet recording head. It is explanatory drawing regarding the image analysis of a recording pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording head 2 Carriage 3 Drive belt 4 Drive pulley 5 Driven pulley 6 Recording medium 7 Delivery roll 8 Take-up roll 9 Conveyance roll
10 base
11 Support frame
12 Spacing adjustment screw
13 Mounting part
20 Inspection mechanism
21 Inspection sheet
22 Feeding roll
23 Winding roll
24 Transport roll
25 Image sensor
26 Pushing member
27 Arm member
30 Air cylinder

Claims (2)

  An ink jet recording apparatus comprising: a recording mechanism that moves an ink jet recording head that discharges ink from nozzles toward a recording medium in a main scanning direction; and a transport mechanism that transports the recording medium in a sub scanning direction. An interval adjusting means for adjusting the interval between the recording surface of the recording medium and the nozzle surface of the ink jet recording head by moving the recording mechanism relative to the transport mechanism, and disposed outside the recording range in the main scanning direction. And a recording state inspection means for inspecting a recording state based on a predetermined pattern recorded on an inspection surface opposite to the nozzle surface, and the inspection surface is separated from the inspection position close to the nozzle surface or the nozzle surface An ink jet recording apparatus comprising: positioning means for positioning at a retracted position.   The inkjet recording apparatus according to claim 1, wherein the positioning unit is provided so as to be interlocked with the movement of the recording mechanism by the interval adjusting unit.

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