JP2011235565A - Drive control method of drawing device, and drawing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive control method of a driving device which can adjust discharge timing in consideration of deviation of landing position during gap adjustment, and to provide a driving device.SOLUTION: The drive control method of a driving device 1 where a gap formed by a nozzle face 91 of an inkjet head 76 and the recording surface A1 of a recording medium A, which is fed relative to the inkjet head 76 for printing along an arc surface, is adjusted uniformly by advance and retreat of the inkjet head 76 in the direction normal to the arc surface and passing through a point deviated from the center of the nozzle face 91 in the print feed direction as the thickness of the recording medium A changes, includes a deviation acquisition step of acquiring the deviation caused by adjustment of the gap, and a timing correction step of correcting discharge timing of the inkjet head 76 based on the deviation thus obtained.

Description

  The present invention relates to a drive control method and a drawing apparatus for a drawing apparatus that performs drawing processing by an inkjet head on a recording medium that is printed and fed along an arc surface.

As this type of drawing device, a device that records images by ejecting ink from a plurality of print heads fixed to a head holding plate on continuous paper conveyed following the outer peripheral surface of a rotating drum is proposed. (See Patent Document 1).
The apparatus has four flat head holding plates provided for each ink color (K, C, M, Y) of the print head, and the four head holding plates are arranged on each plate by the head holding side plate. The drawing operation is performed with the center line of the image being fixed so as to be orthogonal to the normal line of the drum. That is, the four head holding plates are supported by the pair of head holding side plates so that the plates adjacent to each other along the outer peripheral surface of the drum form a mountain shape. The four head holding plates and the pair of head holding side plates are integrated as a unit, and the gap amount (paper gap) between the plurality of print heads and the printing surface of the continuous paper is set to a predetermined amount via each plate. Maintained.

JP 2008-074051 A

However, in the above apparatus, since the four head holding plates for holding a plurality of print heads are unitized as a unit, for example, continuous papers having different thicknesses are introduced and the paper gap is maintained at a predetermined amount. When a plurality of print heads are moved minutely in the normal direction via the four head holding plates, in other words, when the curvature of the continuous paper changes slightly, a plurality of print heads are moved with respect to the movement direction (normal direction) of the entire unit. Move in parallel, the print head slightly moves in the circumferential direction with respect to the outer peripheral surface of the drum, and the landing position shifts.
That is, a plurality of print heads are configured to move as a unit by four unitized head holding plates, and are moved by a predetermined dimension (a) in the normal direction with reference to one print head. When the angle (θ) between one print head and its normal line is set, the other print heads are displaced in the circumferential direction by approximately asin θ, and the landing positions are displaced.

  In view of the above problems, an object of the present invention is to provide a drawing apparatus drive control method and a drawing apparatus capable of adjusting the discharge timing in consideration of the deviation of the landing position in the gap adjustment.

  In the drive control method of the drawing apparatus of the present invention, the gap formed by the nozzle surface of the inkjet head and the recording surface of the recording medium that is printed and fed relative to the inkjet head and along the arc surface is With a drive control method of a drawing apparatus that is adjusted by the forward and backward movement of the inkjet head in the normal direction of the circular arc surface passing through a point deviated from the center of the nozzle surface in the print feed direction with the change in the thickness of the recording medium. A deviation amount acquisition step of acquiring a deviation amount of the landing position caused by the adjustment of the gap, and a timing correction step of correcting the ejection timing of the inkjet head based on the acquired deviation amount, To do.

  The drawing apparatus of the present invention also includes a recording medium feeding means for feeding a recording medium along a recording medium feeding path following the arc surface, an inkjet head for printing on the recording medium being fed, and an inkjet for the recording medium. The head is moved back and forth in the normal direction of the arc surface passing through the point deviated from the center of the nozzle surface in the print feed direction, and the gap between the nozzle surface of the inkjet head and the recording surface of the recording medium is changed to change the thickness of the recording medium. And a control means for controlling the recording medium feeding means, the inkjet head, and the gap adjustment means, and the control means obtains a deviation amount of the landing position caused by the gap adjustment, The ejection timing of the inkjet head is corrected based on the acquired deviation amount.

  According to these configurations, with the change in the thickness of the recording medium, the adjustment of the gap between the nozzle surface of the inkjet head and the recording surface of the recording medium is performed with the normal of the arc surface (curved surface) deviating from the nozzle surface of the inkjet head. When the ink jet head is moved forward and backward, the nozzle surface of the ink jet head is displaced along the arc surface, so that the ejection timing of the ink jet head is corrected in consideration of the amount of landing position deviation caused by the adjustment of the gap. . As a result, even when the gap is adjusted by moving the inkjet head back and forth in the normal direction of the arc surface deviated from the nozzle surface, ink is ejected so that the landing position on the recording medium is an appropriate position. can do. Therefore, the drawing process can be performed with high accuracy.

  In the drive control method for a drawing apparatus of the present invention, it is preferable that the recording medium is printed and fed in close contact with the outer peripheral surface of a rotating drum that rotates in one direction.

  According to this configuration, the present invention can also be applied to a drawing apparatus in which a recording medium is brought into close contact with the outer peripheral surface of a rotating drum (rotating body) and the recording medium is fed by rotating the rotating drum. In the drawing process using the ink, ink can be ejected so that the landing position on the recording medium is an appropriate position.

  In the driving method of the drawing apparatus of the present invention, a plurality of inkjet heads are mounted in half on a pair of sub-plates connected in a mountain shape in the printing feed direction along the arc surface, and the gap adjustment It is preferably performed by moving in the normal direction of the arc surface passing through the boundary of the sub-plate.

  According to this configuration, even in a drawing apparatus in which a plurality of inkjet heads are mounted in half on a pair of sub-plates connected in a mountain shape ("C" shape) in the print feed direction along the arc surface, Since the ejection timing can be corrected based on the deviation amount of the landing position caused by the gap adjustment, the ink can be discharged so that the landing position on the recording medium is an appropriate position.

  In the driving method of the drawing apparatus of the present invention, it is preferable that the parameter for correcting the ejection timing further considers the influence of gravity based on the angle between the ink ejection direction and the vertical direction.

  According to this configuration, it is possible to more accurately eject ink to an appropriate landing position of the recording medium by correcting the ink ejection timing in consideration of the flight speed and the flight curve of the ink due to the influence of gravity. .

  In the driving method of the drawing apparatus of the present invention, it is preferable that the viscosity of the ink is further considered in the parameter for correcting the ejection timing.

  According to this configuration, when printing using a plurality of colors of ink, it is possible to correct the ejection timing in consideration of the high and low viscosity of the ink different in each color (in consideration of the flight speed due to the high and low viscosity). it can. As a result, even when a plurality of colors of ink is used, the ink can be ejected more accurately to an appropriate landing position on the recording medium.

It is a front view of the ink jet device concerning an embodiment. It is side sectional drawing of an apparatus main body. It is a perspective view of a carriage unit. It is sectional drawing around a head unit. It is a perspective view of a print head. It is a perspective view of a head unit. 2 is a block diagram of a control system that controls driving of an inkjet head. FIG. It is the model showing the positional relationship of the rotating drum and inkjet head at the time of gap adjustment. It is a figure showing the relationship between the distance (gap) from a rotating drum to a nozzle surface, and the shift | offset | difference of a landing position. It is a flowchart which controls the discharge timing of an inkjet head.

  Hereinafter, an inkjet apparatus (drawing apparatus) according to an embodiment of the present invention will be described with reference to the accompanying drawings. This ink jet apparatus is a center drum type recording apparatus in which a plurality of ink jet heads are arranged in the circumferential direction, and printing is performed on a long recording medium supplied reel-to-reel using UV ink (ultraviolet curable ink). carry out. The recording medium is, for example, a sheet-like material such as a label film or paper, and has various widths and thicknesses to be printed. In the following description, the direction penetrating the paper surface in FIG. 1 is front and rear, the front side is “front”, and the back side is “rear”. Specifically, the extending direction of the rotating shaft (drum shaft 62) of the rotating drum 61 (described later) is the front and rear, the direction from the drum motor 64 (described later) toward the rotating drum 61 is the front direction (front side), and the rotating drum 61 A direction toward the drum motor 64 is a back direction (back side). In the medium feeding path L of the recording medium A, the medium supply device 6 side described later is referred to as “upstream side”, and the medium recovery device 7 side described later is referred to as “downstream side”.

  As shown in the overall view of FIG. 1, an inkjet apparatus 1 includes a center drum type apparatus main body 2 that performs printing on a recording medium A by an inkjet method, a recording medium A that is supplied with the recording medium A and printed. A reel-to-reel medium supply / recovery device 3 for collecting A and a control device (not shown) for overall control of these components are provided. The medium supply / collection apparatus 3 includes a medium supply apparatus 6 that supplies the recording medium A to the apparatus main body 2 and a medium recovery apparatus 7 that recovers the recording medium A from the apparatus main body 2. On the other hand, the medium feed path L of the recording medium A configured in the apparatus main body 2 and the medium supply / collection apparatus 3 is close to the supply feed path L1 from the medium supply apparatus 6 to the apparatus main body 2 and the circle configured in the apparatus main body 2. An arc-shaped print feed path L2 and a collection feed path L3 from the apparatus main body 2 to the medium collection apparatus 7 are provided.

  The recording medium A supplied from the medium supply device 6 through the supply feed path L1 is fed along the print feed path L2 in the apparatus main body 2, and is used for printing in this portion. In addition, the recording medium A that has been printed is collected by the medium collection device 7 through the collection feeding path L3.

  Furthermore, a UV irradiation unit 44 of the apparatus main body 2 to be described later is disposed between the apparatus main body 2 and the folding unit 25 so as to face the recovery feed path L3.

  When the control device drives the take-up motor in synchronization with the apparatus main body 2, the recording medium A is fed out from the apparatus main body 2 while being given a predetermined tension by the back tension unit 23, and along the recovery feed path L 3. Will be sent. The recording medium A sent out from the apparatus main body 2 first passes through the UV irradiation unit 44. In this passing process, the UV ink is cured. Subsequently, the recording medium A that has been U-turned by the folding unit 25 is wound around the take-up reel 21 via the back tension unit 23. Note that the recording medium A taken up on the take-up reel 21 is introduced into a separate process apparatus and cut as a label or half-cut on the label portion.

  As shown in FIG. 1, the apparatus main body 2 includes a large-diameter rotating drum 61, and a medium feeding mechanism 41 (recording medium feeding unit) that feeds the recording medium A along the print feeding path L <b> 2. The inkjet head (printing head) 76 has a plurality of carriage units 42 arranged radially with respect to the rotary drum 61 so as to face the print feed path L2, and the recovery feed path L3. And a main curing UV irradiation unit 44 for curing the UV ink.

  The plurality of carriage units 42 are units for the colors of the UV ink to be supplied, and constitute a printing unit 48 as a whole.

  As shown in FIG. 2, the apparatus frame 46 includes a base frame 51 serving as a machine base, a main frame 52 erected on the rear half of the base frame 51, and a plate-like subframe widely provided on the front surface of the main frame 52. 53, and a chamber frame 54 disposed in the front portion of the main frame 52 via the subframe 53.

  The main frame 52 is formed by assembling a channel material in a square shape, supports various components via the subframe 53, and supports the medium feeding mechanism 41 having the rotary drum 61 as a main component. The subframe 53 is formed of a thick rectangular stainless steel plate or the like, and supports a plurality of carriage units 42 and UV irradiation units 44 (both see FIG. 1) in a cantilever form on the front side.

  The medium feeding mechanism 41 includes a rotating drum 61 that is formed in a sideways crown shape, a bearing 63 that rotatably supports the rotating drum 61 via a drum shaft 62, and a rotating drum 61 that rotates at a low speed in one direction. A drum motor 64, a belt drive power transmission mechanism 65 interposed between the drum shaft 62 and the drum motor 64, and an encoder 66 attached to the rear end of the drum shaft 62. The drum motor 64 is composed of, for example, a servo motor, and rotates the rotary drum 61 so that the peripheral speed (printing speed) on the outer peripheral surface 71a of the rotary drum 61 is constant. The encoder 66 detects the rotational position of the rotary drum 61 by measuring the rotation amount (rotation angle) of the rotary drum 61.

  The rotary drum 61 includes a cylindrical drum body 71 and a disk portion 72 that covers the rear end of the drum body 71, and is made of a light metal such as aluminum. The recording medium A is fed in close contact with the outer peripheral surface 71a of the drum main body 71 and draws a circle (arc) by the rotating drum main body 71. That is, the recording medium A sent from the medium supply device 6 is sent along the arc-shaped print feed path L2 that follows the outer peripheral surface 71a by the rotary drum 61. Then, printing is performed on the recording medium A by appropriately driving the printing unit 48 in synchronism with this feeding.

  As described above, the printing unit 48 includes the plurality of carriage units 42 arranged radially with respect to the rotary drum 61 (see FIG. 1). The plurality of carriage units 42 are ink color units, and are arranged in the order of cyan (C), magenta (M), yellow (Y), and black (Bk) from the start side to the end side of the print feed path L2. Thus, they are arranged at substantially equal intervals in the circumferential direction. Although details will be described later, a plurality of ink jet heads 76 are mounted on each carriage unit 42, and the plurality of ink jet heads 76 allows a head 77 (line head, see FIG. 7) corresponding to the recording medium A having the maximum width. It is configured. For this reason, the heads 77 of the respective colors sequentially face the recording medium A that is printed and fed along the print feeding path L2, and desired color printing based on the print data is performed on the recording medium A.

  As shown in FIGS. 3 and 4, each carriage unit 42 is slidable on the carriage base 81 in the normal direction of the carriage base 81 fixed to the subframe 53 and the outer peripheral surface 71 a of the rotary drum 61. A box-shaped frame type carriage 82 supported, a head unit 83 mounted on the carriage 82 and mounted with a plurality of inkjet heads 76, and the head unit 83 via the carriage 82 in the normal direction (rotation) of the print feed path L2. A Z-axis moving mechanism 84 (gap adjusting means) that moves forward and backward in the normal direction of the outer peripheral surface 71a of the drum 61, and a head control board module (not shown) that is mounted on the carriage 82 and applies ejection waveforms to the plurality of inkjet heads 76. ) And. Each carriage unit 42 is mounted on a carriage 82 and supported on one outer surface of the carriage 82 via a pinning unit 86 for temporarily curing the UV ink of the recording medium A and a support fitting, and a plurality of inkjet heads 76. And a sub-tank unit (not shown) for supplying UV ink. The control means in the claims mainly includes a control device and a head control board module.

  As shown in FIG. 5, each inkjet head 76 is constituted by a 2-inch inkjet head, and has two nozzle rows 93 composed of a plurality of ejection nozzles 92 parallel to each other on the nozzle surface 91. Yes. In this case, the two nozzle rows 93 are arranged with a 1/2 nozzle pitch position shift in the nozzle row direction.

  On the other hand, as shown in FIGS. 4 and 6, the head unit 83 is detachably attached to the carriage 82 from the front. The head unit 83 includes a head plate 94 and a pair of sub-plates 95 that are supported by the head plate 94 and are connected in a mountain shape (“C” shape) so as to be parallel to the tangent to the rotary drum 61. And a plurality of inkjet heads 76 (7 + 7 in the embodiment) mounted on the pair of sub-plates 95 in half.

  In this case, the plurality of ink jet heads 76 (seven) mounted on each sub-plate 95 are all arranged in a staggered manner in the posture in which the nozzle row 93 faces in the front-rear direction. Further, the plurality of inkjet heads 76 mounted on one sub-plate 95 and the plurality of inkjet heads 76 mounted on the other sub-plate 95 are displaced by 1/4 nozzle pitch position in the front-rear direction (nozzle row direction). Arranged. Thereby, the head 77 as a line head extending in the front-rear direction (width direction of the recording medium A) by all the ink jet heads 76 mounted on the head plate 94, that is, the 1/4 nozzle corresponding to the recording medium A having the maximum width. A pitch head 77 is formed.

  Then, high-resolution rendering (printing) is performed by controlling the ejection timing of ink from each inkjet head 76 (each ejection nozzle 92) by a head control board module (a controller that forms the core of the module). . Although details will be described later, the ejection timing of the inkjet head 76 is adjusted by adjusting the gap (separation distance) between the nozzle surface 91 of the inkjet head 76 and the recording surface A1 of the recording medium A by the advance / retreat of the Z-axis moving mechanism 84. This is determined in consideration of the deviation amount of the ink landing position caused by the above.

  Next, with reference to FIG. 7, a control system for controlling the driving of each inkjet head 76 will be described. As shown in FIG. 7, the inkjet apparatus 1 is provided for each inkjet head 76 as a control system described above, and for each inkjet head 76 that manages drawing ejection data and drive waveform data for each inkjet head 76. Are provided for each of the inkjet heads 76, and the drawing ejection data and drive waveform data from the data management unit 101 and the latch signal from the timing generation unit 102 are used for the inkjet head 76. And a plurality of head drive control units 103 that control driving. The timing generation unit 102 and the head drive control unit 103 are incorporated in the head substrate and the head control substrate module.

  The timing generator 102 receives the encoder signal from the encoder 66, generates a latch signal, and outputs it. For example, the number of pulses of the encoder signal corresponds to the amount of movement of the recording medium A from the initial position, and a latch signal is output based on the amount of movement of the recording medium A and the position of the inkjet head 76. The timing generation unit 102 also includes a correction unit 105 that corrects and outputs a latch signal in accordance with the separation position of the nozzle surface 91 of the inkjet head 76 from the rotary drum 61 by the Z-axis moving mechanism 84.

  The head drive control unit 103 includes a waveform data transfer unit 106, an ejection data transfer unit 107, and a switch group 108. The waveform data transfer unit 106 acquires the drive waveform data from the data management unit 101, receives the latch signal, and transfers the drive waveform data per latch signal to each inkjet head 76 (piezoelectric element thereof). The ejection data transfer unit 107 receives the drawing ejection data from the data management unit 101, decodes the drawing ejection data into each ejection data corresponding to one latch signal, and sequentially outputs the data to the switch group 108. The switch group 108 switches ON / OFF of the transfer of drive waveform data to each piezoelectric element (each discharge nozzle) based on the latch signal and the discharge data from the discharge data transfer unit 107.

  Here, with reference to FIG. 8 and FIG. 9, a control method of the discharge timing accompanying the gap adjustment operation of the head unit 83 by the Z-axis moving mechanism 84 will be described. As described above, the gap adjustment of the head unit 83 is performed by moving the head unit 83 (carriage 82) forward and backward in the normal direction (Z direction in the drawing) of the outer peripheral surface 71a of the rotary drum 61 by the Z-axis moving mechanism 84. Done. At this time, as shown in FIG. 8, the inkjet head 76 mounted on the head unit 83 has a predetermined inclination angle (here, θ degrees) with respect to the movement direction (Z direction) of the Z-axis movement mechanism 84. Therefore, the head unit 83 does not move in the normal direction but moves in parallel to the normal direction of the head unit 83. For this reason, when the movement amount of the head unit 83 is “a”, the inkjet head 76 moves in the normal direction acosθ of itself and is displaced by asinθ in the tangential direction of its own. That is, the inkjet head 76 is displaced from the original position by approximately asin θ in the circumferential direction of the rotary drum 61, and as a result, the landing position is displaced.

  Therefore, in the present embodiment, the ejection timing is corrected for each inkjet head 76 (strictly, each nozzle row 93). However, since the ejection timing and the landing position on the recording medium A also affect the mechanical accuracy of each part in addition to the above asin θ, in this embodiment, in order to correct the deviation of the landing position, a paper gap is previously set. Is maintained at a predetermined value, the gap change between the surface of the rotary drum 61 and the nozzle surface 91 of the ink jet head 76 and the amount of deviation of the landing position caused thereby are actually measured, and this measurement result (FIG. 9). A correction table is created based on the reference), and the ejection timing of the inkjet head 76 is corrected (controlled) based on the correction table.

  That is, as shown in FIG. 10, when changing the paper thickness of the recording medium A, the control device moves the carriage 82 (head unit 83) in the Z direction by the Z-axis moving mechanism 84 in order to maintain the paper gap. The gap (distance) between the nozzle surface 91 of the inkjet head 76 and the outer peripheral surface 71a of the rotary drum 61 is calculated from the moving distance (S01). Next, the head control board module acquires the deviation amount of the landing position from the gap calculation result and the correction table (S02, deviation amount acquisition step). Then, based on the deviation amount of the landing position, an ejection timing signal of the inkjet head 76 is generated (S03, timing correction step). That is, based on the deviation amount of the landing position, a discharge timing signal corrected to advance the discharge timing from a predetermined discharge timing or a discharge timing signal corrected to delay the discharge timing is generated. Then, the head control board module discharges ink from each inkjet head 76 (strictly, each nozzle row 93) based on the generated discharge timing signal, and performs drawing on the recording medium A (S04).

  In such a configuration, with the introduction of the recording medium A having a different thickness, the paper gap is adjusted in the normal direction of the arc surface (the surface of the rotating drum 61) deviated from the nozzle surface 91 of the inkjet head 76. Even if it is performed, the ejection timing of the ink jet head 76 is corrected in accordance with the adjustment of the gap, so that the ink can be ejected so that the landing position on the recording medium A becomes an appropriate position. Therefore, the drawing process can be performed with high accuracy.

  Note that the plurality of head units 83 of the embodiment are arranged at equal intervals in the circumferential direction of the rotary drum 61, and the ink ejection directions vary from those close to horizontal to those close to vertical. Therefore, the gravity acting on the ink that is ejected and in flight also varies. Further, the flying speed of the ink slightly changes depending on the weight (specific gravity) of the ink used. For this reason, it is more preferable that the correction table shown in FIG. 9 is created for each inkjet head 76 (or for each nozzle row 93) and the ejection timing is corrected for each inkjet head 76 in consideration of these factors.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet apparatus 41 ... Medium feed mechanism 61 ... Rotating drum 84 ... Z-axis moving mechanism 91 ... Nozzle surface 95 ... Subplate A ... Recording medium A1 ... Recording surface

Claims (6)

The gap formed by the nozzle surface of the inkjet head and the recording surface of the recording medium that is printed and fed relative to the inkjet head and along the arc surface is accompanied by a change in the thickness of the recording medium. A drive control method for a drawing apparatus that is adjusted to be constant by the forward and backward movement of the inkjet head in the normal direction of the arc surface passing through a point deviating from the center of the nozzle surface in the print feed direction,
A deviation amount acquisition step of acquiring a deviation amount of the landing position caused by the adjustment of the gap;
And a timing correction step of correcting the ejection timing of the inkjet head based on the acquired deviation amount.   2. The driving control method for a drawing apparatus according to claim 1, wherein the recording medium is fed and printed in close contact with an outer peripheral surface of a rotating drum that rotates in one direction. A plurality of the inkjet heads are mounted in half on a pair of sub-plates connected in a mountain shape in the print feed direction along the arc surface,
The drawing apparatus drive control method according to claim 1, wherein the adjustment of the gap is performed by moving the gap in a normal direction of the arc surface passing through a boundary between the pair of sub-plates.   4. The parameter for correcting the ejection timing further considers an influence of gravity based on an angle formed between an ink ejection direction and a vertical direction. Drive control method for a drawing apparatus.   5. The driving control method for a drawing apparatus according to claim 1, wherein the parameter for correcting the ejection timing further considers the viscosity of the ink. Recording medium feeding means for feeding the recording medium along a recording medium feeding path following the arc surface;
An inkjet head for printing on the recording medium being sent;
The inkjet head is moved forward and backward with respect to the recording medium in the normal direction of the arc surface passing through a point deviated from the center of the nozzle surface in the print feed direction, and the nozzle surface of the inkjet head and the recording surface of the recording medium Gap adjusting means for adjusting the gap of the recording medium to be constant as the thickness of the recording medium changes,
Control means for controlling the recording medium feeding means, the inkjet head and the gap adjusting means,
The drawing device is characterized in that the control means acquires a deviation amount of the landing position caused by the adjustment of the gap, and corrects the ejection timing of the inkjet head based on the acquired deviation amount.

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