WO2007065275A1 - Control system for liquid applying apparatus - Google Patents

Control system for liquid applying apparatus Download PDF

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Publication number
WO2007065275A1
WO2007065275A1 PCT/CA2006/002014 CA2006002014W WO2007065275A1 WO 2007065275 A1 WO2007065275 A1 WO 2007065275A1 CA 2006002014 W CA2006002014 W CA 2006002014W WO 2007065275 A1 WO2007065275 A1 WO 2007065275A1
Authority
WO
WIPO (PCT)
Prior art keywords
substrate
pattern
data
liquid
firing
Prior art date
Application number
PCT/CA2006/002014
Other languages
French (fr)
Inventor
Ross Hoge
James Koehler
Louis Dupuis
Original Assignee
Pat Technology Systems Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pat Technology Systems Inc. filed Critical Pat Technology Systems Inc.
Publication of WO2007065275A1 publication Critical patent/WO2007065275A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
    • F26B25/001—Handling, e.g. loading or unloading arrangements
    • F26B25/003—Handling, e.g. loading or unloading arrangements for articles
    • F26B25/004—Handling, e.g. loading or unloading arrangements for articles in the shape of discrete sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/0015—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form for treating before, during or after printing or for uniform coating or laminating the copy material before or after printing
    • B41J11/002—Curing or drying the ink on the copy materials, e.g. by heating or irradiating
    • B41J11/0021—Curing or drying the ink on the copy materials, e.g. by heating or irradiating using irradiation
    • B41J11/00214—Curing or drying the ink on the copy materials, e.g. by heating or irradiating using irradiation using UV radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J29/00—Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
    • B41J29/377—Cooling or ventilating arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/28—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2252/00—Sheets
    • B05D2252/04—Sheets of definite length in a continuous process
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
    • B05D3/061—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
    • B05D3/065—After-treatment
    • B05D3/067—Curing or cross-linking the coating

Definitions

  • the present invention relates to the application of a liquid to a substrate, more particularly to a method and system for registering a pattern of such a liquid.
  • Some digital printing methods provide mechanical means for holding the substrate in a given position, such that the liquid can be applied in register with the substrate.
  • mechanical means can induce variations in the position of the substrate and must be generally adapted to the substrate size.
  • a system for registering a pattern of liquid to be applied by fluid ejection heads on a moving substrate comprising a firing pattern calculator adapted to receive pattern data corresponding to the pattern of liquid to be applied on the substrate, and to generate firing pattern data corresponding to a firing sequence of the fluid ejection heads to obtain the pattern of liquid on the substrate when the substrate is m a reference position with respect to the fluid ejection heads, a speed sensor sensing a speed of the moving substrate and producing corresponding speed data, at least one position sensor sensing an actual position of the substrate upstream of the fluid ejection heads and producing corresponding position data, an offset calculator adapted to receive the position data from the position sensor and to generate offset data corresponding to a difference m the firing sequence brought by a difference between the actual position of the substrate and the reference position, and a controller adapted to receive the speed data, and to determine a register delay and a line delay using the speed data, the register delay corresponding to a
  • a method of registering a pattern of a liquid to be applied on a moving substrate by an array of ejection heads comprising determining a desired pattern of the liquid on the substrate, determining a firing pattern of the ejection heads based on the desired pattern, the firing pattern corresponding to the substrate being m a reference position, detecting a position of the substrate upstream of the ejection heads, determining a difference between the position of the substrate and the reference position, determining an offset to be applied to the firing pattern corresponding to the difference between the position of the substrate and the reference position, applying the offset to the firing pattern to obtain a corrected firing pattern, and actuating the ejection heads according to the corrected firing pattern.
  • a method of producing at least one desired gloss level on a substrate comprising selecting the at least one desired gloss level for the substrate, depositing an uncured liquid on the substrate in a plurality of drops to form a pattern of the uncured liquid, at least one of a size of the drops and a distance between adjacent drops being selected according to the desired gloss level, and curing the liquid.
  • Fig. 1 is a side cross-sectional, schematic view of a liquid applying apparatus according to a particular embodiment of the present invention
  • Fig. 2 is a side view of part of the apparatus of
  • FIG. 1 showing a feeder system thereof
  • FIG. 3 is a perspective schematic view of a liquid applying apparatus according to an alternate embodiment of the present invention.
  • FIG. 3 showing a feeder system thereof
  • FIG. 5 is a block diagram of a control system of a liquid applying apparatus such as shown m Figs. 1-4 according to a particular embodiment of the present invention
  • Fig. 6 is a block diagram of a tray control system of the system of Fig. 5 ;
  • Fig. 7 is a block diagram of a height control system of the system of Fig. 5;
  • Fig. 8 is a block diagram of a speed control system of the system of Fig. 5;
  • Fig. 9 is a block diagram of a feeder control system of the system of Fig. 5;
  • Fig. 10 is a block diagram of a pattern control system of the system of Fig. 5;
  • Fig. 11 is a block diagram of a safety system of the system of Fig. 5.
  • a liquid applying apparatus 10 generally comprises a feeder system 12 picking up sheets 14 from a first pile, a receiver system 16 receiving the sheets 14 m a second pile, a rotating drum 18 transporting the sheets 14 from the feeder system 12 to the receiver system 16, and at least one array of fluid ejection heads 20 distributing a liquid, such as for example a coating liquid, on the sheets 14 while they are transported by the drum 18.
  • the feeder system 12 comprises a tray system 38 including an angled bottom wall 40 supporting a pile of sheets 14, and spaced apart side walls 42 and an end wall 44 surrounding the sheets.
  • the walls 42, 44 are preferably connected to appropriate driving means 46 such as to be able to accurately adjust the distance therebetween to correspond to a selected sheet size.
  • the angled wall 40 is movable along a direction substantially perpendicular thereto through appropriate driving means 48 such as to be able to keep the topmost sheet of the pile at a substantially constant height .
  • the feeder system 12 includes actuators 70 inclined with respect to the pile of sheets 14 and having flexible vacuum cups 74 at their lower end.
  • the actuators 70 lower the vacuum cups 74 until they are compressed against the pile of sheets 14, in a beveled manner because of the inclination of the actuators 70.
  • the vacuum system of the cups 74 is activated, attaching the top sheet 14 thereto.
  • the actuators 70 lift the vacuum cups 74 to their topmost position, lifting the grabbed sheet, which becomes inclined when the vacuum cups 74 return to their non-beveled state.
  • Adjacent air nozzles 82 blow air under the sheet 14 to help the separation of the sheet from the remaining pile.
  • the actuators 70 are then moved downstream under the action of actuators 62 such that the end of the sheet 14 rests between spaced apart top and bottom rollers 58, 78.
  • the top rollers 58 are moved against the bottom roller 78 by actuators 54, and the vacuum is released on the cups 74.
  • the bottom roller 78 starts to turn, moving the sheet 14 along a slide plate 86 toward the drum 18.
  • An end roller 88 rotates through contact with the drum 18, and presses the sheet 14 against the drum 18 as the sheet 14a leaves the slide plate 86 to be "grabbed” by the vacuum system of the drum 18.
  • the top rollers 58 and actuators 70 are then returned to their original position and the bottom roller 78 stops rotating. [0026] Referring back to Fig.
  • the rotating drum 18 is adapted to retain sheets 14 of various sizes.
  • the drum 18 includes a circumferential wall 94 and is rotationally received on a drum shaft 96.
  • the circumferential wall 94 is engaged to a driving belt 102 which is engaged to a pulley 104, the pulley 104 being driven by a motor 106 or other appropriate driving means such as to rotate the drum 18 in a continuous manner.
  • the circumferential wall 94 includes a plurality of holes (not shown) defined therethrough and is under vacuum such as to retain the sheets thereon.
  • the heads 20 are retained in a fixed manner over the drum, although in an alternate embodiment the heads 20 are movable.
  • One or more array of heads 20 can be provided, such as for example to distribute different liquids.
  • Each head 20 is equipped with an array of aligned, regularly spaced apart small nozzles (not shown) , each nozzle being controlled independently.
  • the heads 20 are in fluid communication with a reservoir of liquid, which m a particular embodiment is a coating liquid, but can alternately be any other liquid adapted to be distributed by the heads 20 such as for example ink, adhesive, silicon release agent, conductive ink, etc.
  • Each nozzle can produce a small, precise jet of liquid depositing a single drop on the substrate.
  • the heads 20 are selected according to the precision of the liquid pattern to be applied, with heads having smaller nozzles placed closer together providing a more precise distribution of the liquid.
  • the heads distribute a coating liquid, or a type of ink adapted to produce a variable gloss effect
  • various degrees of gloss can be obtained with a same liquid by varying at least one of the size of the liquid drop deposited by each nozzle and the distance between the drops deposited on the substrate (i.e. between subsequent firing nozzles) , before the liquid is cured.
  • at least one other layer of liquid can be deposited thereover using a similar technique. For example, by depositing small drops of coating liquid which are spaced apart from each other, the coating obtained will have a mat finish.
  • the coating becomes progressively more glossy.
  • the coating obtained can take the form of a smooth, mirror-like glossy surface. This allows for the creation of a variation in gloss level for a same substrate or between subsequent substrates while using the same liquid, while allowing the creation of the smooth, mirror-like surface in a single pass, and without requiring the application of a film over the liquid during curing as in the case of many prior art methods .
  • a curing or drying apparatus 140 for the liquid is supported over the drum 18 downstream of the array of heads 20.
  • the liquid is a coating liquid curable through exposition to ultra-violet light, and as such the curing apparatus 140 includes one or more ultra-violet lamps (not shown) .
  • the liquid can be a solvent-based or a water- based fluid, and the apparatus 140 can include infra-red lamps, a micro-wave emitter, and/or any other type of appropriate curing or drying system.
  • the receiver system 16 includes a tray system 148 similar to that of the feeder system 12 described above, i.e. with a movable angled bottom wall 150, end wall 152 and parallel side walls 154, such as to receive and align the sheets 14 coming off of the drum 18.
  • the receiver system 16 also includes a pivotable slide plate 156 for detaching the sheets 14 from the drum 18.
  • the slide plate 156 is pivotable between a first position coming between the incoming sheet 14 and the drum 18 and a second position away from the drum 18 under the action of actuators 158.
  • Similar or equivalent mechanisms can also be provided at various points around the drum 18 such as to be actuated when a damaged sheet (for example a crumpled sheet or a double sheet) is present to remove that sheet from the drum 18, thus preventing the damaged sheet from damaging sensitive elements of the apparatus, for example the heads 20 or the curing/drying apparatus 140.
  • a damaged sheet for example a crumpled sheet or a double sheet
  • the apparatus 210 generally comprises a feeder system 212 picking up sheets 14 from a first pile, a receiver system 216 receiving the sheets 14 in a second pile, a conveyor 218 transporting the sheets 14 from the feeder system 212 to the receiver system 216, and at least one array of fluid ejection heads 20 distributing liquid on the sheets 14 while they are transported by the conveyor 218.
  • the feeder system 212 comprises a tray 238 receiving a pile of sheets, with side walls 242 of the machine 210 (only one of which is shown) surrounding the pile of sheets 14.
  • Centering guides 245 surround the front edge of the sheets 14, and the feeder 212 preferably includes means to adjust the distance therebetween such as to adjust to sheets of different sizes, as in the previous embodiment.
  • the tray 238 is supported to be movable along a substantially vertical or vertical direction, through appropriate driving means 248, such as to be able to keep the topmost sheet of the pile at a substantially constant height.
  • the feeder system 212 includes vertical arm actuators 270, the bottom end 272 of each arm actuator 270 including a vacuum cup 274.
  • the arm actuators 270 lower the vacuum cups 274 until they are compressed against the top sheet, and the vacuum system is activated to attach to top sheet to the vacuum cups 274.
  • the arm actuators 270 are then tilted under the action of a tilt actuator 262, lifting the front edge of the sheet.
  • the arm actuators 270 lift the vacuum cups 274 to their topmost position, lifting the grabbed sheet 14 from the pile.
  • Air which can be ionized, comes from front and rear air nozzles 282, 283 to facilitate the separation of the sheet from the remaining sheets 14.
  • the arm actuators 270 are then rotated to their original vertical orientation by the tilt actuator 262, and moved downstream toward the conveyor 218 by a horizontal actuator 254, until the front end of the sheet rests between spaced apart top and bottom nip rollers 258, 278.
  • the top nip roller 258 is then moved to press against the bottom nip roller 278, sandwiching the end of the sheet therebetween.
  • the vacuum is released on the cups 274 and the bottom roller 278 starts to turn, moving the sheet 14 toward the conveyor 218.
  • the sheet is then "grabbed” by the vacuum of the conveyor 218.
  • the top nip roller 258 and arm actuators 270 are then returned to their original position, and the bottom roller 278 stops rotating.
  • the conveyor 218 is adapted to retain sheets 14 of various sizes.
  • the conveyor 218 includes a conveyor belt 294 defining a support surface 300 for the sheets, which is preferably non-stick such as to facilitate clean-up in case of a spilling of liquid thereon.
  • the conveyor belt 294 includes a series of holes 310 defined therethrough across the support surface 300.
  • the conveyor 218 includes a downstream roller 305 driven by appropriate driving means 306 such as to rotate the conveyor belt 294 in a continuous manner.
  • a vacuum system (not shown) creates a vacuum only in the top section of the conveyor belt 294.
  • the sheets 14 are received and retained on the support surface 300 by the vacuum, and released when they arrive in proximity of the receiver system 216 where the conveyor belt 294 is no longer in communication with the vacuum system.
  • the heads 20 and curing or drying apparatus 140 are similar to the heads and curing or drying apparatus described in the previous embodiment, and as such will not be further described herein.
  • the receiver system 216 includes a tray 348 similar to that of the feeder system 212 described above, with the sheets 14 being received on top of the bottom wall 350 and enclosed by side walls 354 of the machine.
  • the receiver system 216 preferably includes centering guides (not shown) such as the centering guides 245 of the feeder system 212, with means to adjust the distance therebetween such as to adjust to sheets of different sizes.
  • the tray 348 is supported at a fixed height. However, the tray 348 can alternately be supported m a vertically movable manner, similarly to the tray 238 of the feeder system 212 described above.
  • both liquid applying machines 10, 210 are controlled by a control system, which comprises a mam controller 400 receiving data from a data entry module 402 and coordinating a tray control system 404, a safety system 406, a pattern control system 408, a feeder control system 410, a speed control system 412 and a height control system 414.
  • a control system which comprises a mam controller 400 receiving data from a data entry module 402 and coordinating a tray control system 404, a safety system 406, a pattern control system 408, a feeder control system 410, a speed control system 412 and a height control system 414.
  • the data entry module 402 collects information from a user on the coating and/or printing and/or cutting operation (s) to be performed by the apparatus 10, 210, and sends this information to the mam controller 400 m the form of pattern data (including the position and thickness of the coating liquid/ink/cutting liquid to be applied) , desired speed data for the process, frequency data (i.e. spacing between consecutive sheets) sheet size data, user correction data (containing register corrections entered manually by the user) , etc.
  • the data entry module 402 also sends an actuation signal to the controller when the user has indicated, for example by pressing a button, that the process can begin.
  • the data entry module 402 can take the form, for example, of a user interface such as a keyboard or any other source of commands, or receive data from a portable medium connected thereto.
  • the pattern data and sheet size data can be stored onto a portable medium, and the desired speed data, frequency data and user correction data can be created upon actuation by the user of a user interface.
  • the position corrections can be indicated through the user interface, which creates the user correction data accordingly.
  • the data entry module can also receive a feedback signal from the main controller 400, which allows it to display information on the process for the user.
  • the main controller 400 upon reception of the data from the data entry module 402, sends the sheet size data to the tray control system 404, more specifically to a tray controller 416.
  • the tray controller 416 receives position data from sensors 418 of the walls or centering guides 42, 44, 245, 152, 154 of the feeder systems 12, 212 and receiver systems 16, 216, and actuates the motors or other driving means 46 (shown for the apparatus 10 m Fig. 1) of the walls or guides until the position data received corresponds to the sheet size data.
  • the main controller 200 can also send a signal instructing the tray controller 416 to oscillate, jog or vibrate the walls or centering guides 42, 44, 245, 152, 154 through appropriate actuation of the motors 46, such as to facilitate stacking of the sheets 14 m an aligned manner.
  • the tray controller 416 sends a status signal to the main controller 400 to indicate whether the position of the walls or centering guides 42, 44, 245, 152, 154 is adequate.
  • the feeder systems 12, 212 and receiver systems 16, 216 have trays with non-movable walls or centering guides, and the tray controller 416 is omitted .
  • the main controller 400 also sends an actuation signal to the height control system 414, more specifically to a height controller 420.
  • the height controller 420 receives height data from a sheet height sensor 422 (see also Figs. 2 and 4) , which is located m the feeder system 12, 212 over the pile of sheets 14 to determine the height of the topmost sheet of the pile 14.
  • the sheet height data includes an actual distance between the sensor 422 and the topmost sheet, and the height controller 420 compares the sheet height data received to a reference value and activates the motor or other driving means 48, 248 (see also Figs.
  • the height sensor 422 can alternately or additionally (e.g. as a fail-safe mechanism) include a switch 423 (see Fig. 4) , and the sheet height data includes a signal from the switch 423 (producing an actuation signal when the topmost sheet is at the appropriate height and actuates the switch 423) such that the height controller 420 activates the motor or other driving means 48, 248 moving the wall up 40, 240 until that actuation signal is received.
  • the sheet height controller 420 sends a status signal to the main controller 400 so as to indicate whether the sheet height is adequate.
  • the height controller 420 regulates the sheet height throughout the entire liquid application process.
  • the main controller 400 sends the desired speed data to the speed control system 412, more particularly to a speed controller 424.
  • the speed controller 424 receives real speed data from a speed sensor 426 (see also Figs. 1 and 3) , which measures the speed of rotation of the drum 18 or conveyor 218.
  • the speed sensor 426 is an encoder contacting the circumferential wall 94 or conveyor belt 294 in proximity of the heads 20.
  • the speed controller 424 actuates the drum or conveyor driving means 106, 306 (see Figs. 1 and 3) and regulates the speed thereof so as to match the real speed data as closely as possible with the desired speed data.
  • the speed controller 424 sends the real speed data to the main controller 400.
  • the main controller 400 sends the real speed data and frequency data to the feeder control system 410, more particularly to a feeding controller 428.
  • the feeding controller 428 actuates a motor 430 (or other driving means) rotating the bottom roller 78, 278 and the actuators of the feeder system 12, 212 (such as 54, 62, 70, 254, 262, 270 of Figs. 2 and 4) such that the motions of the vacuum cups 74, 274 and top rollers 58, 258 as well as the rotation of the top rollers 78, 278 are coordinated both with each other and with the real speed of the drum 18 or conveyor 218.
  • the actuators 54, 62, 70, 254, 262, 270 and motors 430 send feedback signals to the feeding controller 428.
  • the feeding controller 428 sends a status signal to the main controller 400 indicating that the feeder system 12, 212 is operating.
  • the main controller 400 sends the sheet size data, user correction data, pattern data and real speed data to the pattern control system 408, more particularly to a pattern controller 432.
  • the pattern controller 432 sends the pattern data to a firing pattern calculator 434, which establishes a firing pattern for the nozzles of the heads 20 according to the pattern data.
  • the firing pattern calculator 434 sends firing pattern data to the pattern controller 432, indicating which nozzles should be fired for each line of the pattern.
  • the firing pattern data is calculated based on a reference position, for example with the sheet being perfectly aligned with the direction of travel and in the exact center of the array of heads .
  • the system includes a bar code reader (not shown) which reads a bar code on the substrate upstream of the heads 20, and the main controller 400 selects the pattern data from a list according to the bar code read.
  • the bar code could also be used as a confirmation of the pattern data provided by the user.
  • the pattern controller 432 also sends the sheet size data and the user correction data to an offset calculator 436.
  • the offset calculator 436 receives position data from at least one sheet position sensor 438 (see also Figs. 1 and 3) .
  • the • sheet position sensor 438 which can be for example an ultrasonic sensor, infrared sensor, laser sensor or CCD sensor, is retained over the drum 18 or conveyor 218 upstream of the array of coating heads 20.
  • the sheet position sensor 438 indicates through the position data the position of the sheet 14, for example by detecting the front edge of the sheet 14 or a specific printed pattern or target (whether printed or else, such as for example the presence of glitter material) on the sheet 14.
  • the position data can include a lateral position of the sheet (i.e. a position of the sheet in a direction perpendicular to the direction of travel) and a skew of the sheet 14, i.e. how much the sheet 14 is turned with respect to the direction of travel.
  • the offset calculator 436 thus calculates, based on the position data, the relative position of the sheet 14 with respect to the reference position, and calculates a necessary offset to be applied to the firing pattern data.
  • the offset calculator 436 also adds the user correction data (if any is provided) to the offset calculated, and then sends corresponding offset data to the pattern controller 432.
  • the pattern controller 432 calculates a longitudinal register delay between the sheet 14 passing under the sheet position sensor 438 and the actuation of the heads 20 based on the real speed data. After the longitudinal register delay, the pattern controller 432 actuates the nozzles of the heads 20 following the firing pattern data but offset m accordance with the offset data to perform a lateral and skew register for the sheet 14, a delay between each line of the pattern being selected according to the real speed data. This allows for the liquid to remain m register with the sheets even when successive sheets are not perfectly aligned.
  • the pattern controller 432 thus applies the same firing pattern data to all the sheets following successive offset data which vary from one another in lateral and/or skew register. As such, the firing pattern data is not changed but rather the position where it is applied is moved by a given increment, simply by applying this increment to the nozzle selection. As such, corrections can be performed quickly without recalculating the firing pattern data and without the need to re-rip the source image of the pattern, thus without the need for access to the source image and/or the software used to create it.
  • the quick corrections substantially reduce waste material produced when adjusting the register of the coating pattern with the sheets and eliminate the time which would otherwise be necessary to re- rip the source image m between corrections.
  • the nozzles of the heads 20 can be subsequently numbered in relation to their relative position, and as such the firing pattern data includes a series of numbers representing the nozzles to be fired to obtain the desired pattern, with optionally a drop size associated with each nozzle.
  • the offset data includes an operation to be performed to the number sequence representing the nozzle selection, corresponding to the difference between the relative position of the sheet 14 with respect to the reference position, such as a translation of a given number of nozzles m a given direction.
  • the pattern controller 272 thus performs this operation on the firing pattern data to obtain a corrected pattern data which is used to actuate the corresponding nozzles of the heads 20.
  • the pattern controller 432 sends a second pass signal to the main controller 400, which m turn will indicate to the feeder control system 410, through the frequency data, that no sheet should be fed.
  • the pattern controller 432 also actuates the actuator 158 of the slide plate 156 of the receiver system 16 (see Fig. 1) such that the slide plate 156 moves away from the drum 18, allowing the sheet 14 to remain on the drum 18 for a second pass.
  • the pattern controller 432 or main controller 400 can actuate the driving means 306 of the conveyor 318 such that the conveyor 318 backs up to bring the sheet back under the heads 20.
  • the main controller 400 sends the real speed data to the safety system 406, more particularly to the safety controller 440.
  • the safety controller 440 receives data from a crumpled sheet sensor 442, a sheet quantity sensor 444 and a sheet presence sensor 446.
  • the crumpled sheet sensor 442 is retained just downstream of the feeder system 12, 212.
  • the crumpled sheet sensor 292 is composed of two receiving units placed on one side of the circumferential wall 94 or the conveyor belt 294, and two emitting units placed on the other side of the circumferential wall 94 or the conveyor belt 294 and aligned with the receiving units.
  • Each emitting unit sends an infrared beam to a corresponding one of the receiving units, the two beams crossing each other at a given distance above the circumferential wall 94 or the conveyor belt 294.
  • the crumpled corner interrupts at least one of the infrared beams, and the crumpled sheet sensor 442 sends a crumpled sheet signal to the safety controller 440.
  • a similar crumpled sheet sensor can also be provided downstream of the curing/drying apparatus 140 (not shown) or at any other appropriate location .
  • the sheet quantity sensor 444 is retained just downstream of the feeder system 12, 212, before the sheet engages the drum 18 or conveyor 218.
  • the sheet quantity sensor 444 is for example an ultrasonic sensor which can detect if a single or multiple sheets are being fed to the drum 18 or conveyor 218.
  • the sheet number sensor upon detection of a single or multiple sheets, the sheet number sensor respectively sends a single sheet signal or multiple sheet signal to the safety controller 440.
  • the sheet presence sensor 446 is retained over the drum 18 or conveyor 218 downstream of the curing/drying apparatus 140. Referring to Fig. 11, the sheet presence sensor 446 detects the presence of a sheet exiting from the curing/drying apparatus 140, and sends a sheet presence signal to the safety controller 440.
  • the safety controller 440 upon receiving a crumpled sheet signal or a multiple sheet signal, actuates the appropriate ejection mechanism 450 (which can be for example similar to the slide plate 156 of the receiver system 16 of the apparatus 10) to remove the crumpled sheet or multiple sheets from the drum 18 or conveyor 218. Also, upon reception of the single sheet signal, the safety controller 440 calculates, based on the real speed data, an expected delay between the reception of the single sheet signal (i.e. sheet exiting the feeder 12, 212) and the reception of the sheet presence signal (i.e. sheet exiting the curing/drying apparatus 140) .
  • the safety controller 440 If the safety controller 440 has not received the sheet presence signal within the expected delay, then the sheet must be stuck somewhere, potentially under the curing/drying apparatus 140 where it can become a fire hazard.
  • the safety controller 440 thus sends a status signal to the main controller 400 which stops the process so that the stuck sheet can be removed.
  • the main controller 400 or safety controller 440 can also activate other types of safety mechanisms, such as for example the closing of a shutter (not shown) on the curing or drying apparatus 140 to reduce the risk of fire.
  • the drum 18 or conveyor 218 can be replaced by other equivalent means of moving sheets 14, or by means of moving a paper web, such as for example a series of rollers driving the web to and from the heads 20.
  • the heads 20 can be used to apply liquid to either sheets or web on both sides thereof, for example by having one or more series of heads 20 installed on each side of a web being driven by a series of rollers.
  • the heads 20 can be installed on a movable support actuated by the pattern controller 432 to move the heads 20 according to the pattern data.
  • the sheet can be in a fixed position during the coating process, if the moveable support is moveable along the entire surface of the sheet.
  • the sheet can alternately be incrementally moved in a first direction, the heads being moved in a second direction perpendicular to the first one between each increment of the movement of the sheet, using a mechanism similar to that of a desktop inkjet printer. In both cases, a single head could be used instead of the array of heads 20.
  • the distance between the heads 20 and the drum 18 or conveyor 218 can be adjusted, such as to obtain an optimal distance between the substrate and heads 20, for example lmm, regardless of the thickness of the substrate .
  • the apparatus 10, 210 can have multiple arrays of heads 20 such as to apply a same or a different liquid to the substrate.
  • one or more sheet position sensor (s) 438 can be provided upstream of each array of heads such as to detect the precise position of the sheet, and send a signal to a respective pattern control system accordingly.
  • Each pattern control system similar to the pattern control system 408 described above, creates a firing pattern data based on the particular pattern data for the corresponding array of heads, and offset data based on the corresponding user correction data and sheet position data.
  • the overall register can be quickly adjusted before application of the liquid (s) on the substrate without the need to re-rip the source image of the pattern, reducing waste generated by the production of the finished product.
  • all the operations are digital, the pattern of one or all the operations can easily be changed without the need to change a physical element of the machine, which greatly simplifies the necessary preparation between the production of two different finished products.
  • the apparatus 10, 210 can effectively produce a series of proofs that correspond perfectly to the finished product, as proofs and finished product are produced by a same machine.
  • the apparatus 10 can advantageously be used in line with other paper or web processing machines, for example with a printing machine producing printed sheets that are usually disposed in a stack at the exit point of the printing machine.
  • a conveyor or similar sheet transporting means can be provided at the exit point to intercept the printed sheets and transport them to the apparatus 10, for example to the tray system 38 of the feeder system 12, where the sheets are picked up and placed on the drum 18, coated by coating liquid applied by the heads 20, cured by the curing apparatus 140 and stacked by the receiver system 16, as described above.
  • the apparatus 210 without the feeder system 212 and receiver system 216, can be installed in line with a printing machine, the sheets exiting the printing machine directly onto the conveyor 218 to be coated by the heads 20, and/or in line with a cutting machine, the sheets exiting the conveyor 218 to be picked up by the cutting machine. As such, the time and labor necessary to transport the sheets from one machine to the apparatus 10, 210 are saved.

Abstract

A system for registering a pattern of liquid to be applied by fluid ejection heads (20) on a moving substrate (14), including a firing pattern calculator (434) adapted to receive pattern data corresponding to the pattern of liquid to be applied and to generate firing pattern data corresponding to a firing sequence of the heads (20) to obtain the pattern when the substrate is in a reference position, a speed sensor (426) sensing a speed of the substrate (14) and producing corresponding speed data, at least one position sensor (438) sensing a position of the substrate (14) upstream of the heads (20) and producing corresponding position data, an offset calculator (436) adapted to receive the position data and to generate offset data corresponding to a difference in the firing sequence brought by a difference between the position and the reference position, and a controller (432) actuating the heads (20) based on the offset data applied to the firing pattern data.

Description

CONTROL SYSTEM FOR LIQUID APPLYING APPARATUS
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to the application of a liquid to a substrate, more particularly to a method and system for registering a pattern of such a liquid.
2. Background Art
[0002] Contact methods of applying a liquid such as a coating or ink to a substrate, e.g. through rollers, plates, or blankets, generally provide a register of the pattern of liquid by examining the substrate to which the liquid has been applied, determining if a correction of register is necessary, and manually moving the various components of the application system to attempt performing the correction. Often, several attempts are necessary to obtain an adequate register of the pattern. As the corrections are performed after the liquid has been applied on the substrate, such methods and system of registering usually produce a substantial amount of waste material (i.e. substrate to which the liquid has been improperly applied) before obtaining the desired register.
[0003] Some digital printing methods provide mechanical means for holding the substrate in a given position, such that the liquid can be applied in register with the substrate. However, such mechanical means can induce variations in the position of the substrate and must be generally adapted to the substrate size.
[0004] Other digital printing methods recalculate the digital printing pattern from the original image to be printed according to the position of the substrate. Such a method usually requires access to the original image, and requires increasing computing time as the size and complexity of the image increases. SUMMARY OF INVENTION
[0005] It is therefore an aim of the present invention to provide an improved system for registering a pattern of liquid to be applied by fluid ejection heads on a moving substrate .
[0006] It is also an aim of the present invention to provide an improved method of registering a pattern of a liquid to be applied on a moving substrate by an array of ejection heads.
[0007] It is a further aim of the present invention to provide an improved method of producing at least one desired gloss level on a substrate.
[0008] Therefore, m accordance with the present invention, there is provided a system for registering a pattern of liquid to be applied by fluid ejection heads on a moving substrate, the system comprising a firing pattern calculator adapted to receive pattern data corresponding to the pattern of liquid to be applied on the substrate, and to generate firing pattern data corresponding to a firing sequence of the fluid ejection heads to obtain the pattern of liquid on the substrate when the substrate is m a reference position with respect to the fluid ejection heads, a speed sensor sensing a speed of the moving substrate and producing corresponding speed data, at least one position sensor sensing an actual position of the substrate upstream of the fluid ejection heads and producing corresponding position data, an offset calculator adapted to receive the position data from the position sensor and to generate offset data corresponding to a difference m the firing sequence brought by a difference between the actual position of the substrate and the reference position, and a controller adapted to receive the speed data, and to determine a register delay and a line delay using the speed data, the register delay corresponding to a time of a first actuation of the fluid ejection heads and the line delay corresponding to a time between an application of a line and a subsequent line of the pattern of liquid, the controller actuating the fluid ejection heads after the register delay based on the offset data and line delay applied to the firing pattern data.
[0009] Also m accordance with the present invention, there is provided a method of registering a pattern of a liquid to be applied on a moving substrate by an array of ejection heads, the method comprising determining a desired pattern of the liquid on the substrate, determining a firing pattern of the ejection heads based on the desired pattern, the firing pattern corresponding to the substrate being m a reference position, detecting a position of the substrate upstream of the ejection heads, determining a difference between the position of the substrate and the reference position, determining an offset to be applied to the firing pattern corresponding to the difference between the position of the substrate and the reference position, applying the offset to the firing pattern to obtain a corrected firing pattern, and actuating the ejection heads according to the corrected firing pattern.
[0010] Further in accordance with the present invention, there is provided a method of producing at least one desired gloss level on a substrate, comprising selecting the at least one desired gloss level for the substrate, depositing an uncured liquid on the substrate in a plurality of drops to form a pattern of the uncured liquid, at least one of a size of the drops and a distance between adjacent drops being selected according to the desired gloss level, and curing the liquid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Reference will now be made to the accompanying drawings, showing by way of illustration a particular embodiment of the present invention and m which:
[0012] Fig. 1 is a side cross-sectional, schematic view of a liquid applying apparatus according to a particular embodiment of the present invention; [0013] Fig. 2 is a side view of part of the apparatus of
Fig. 1, showing a feeder system thereof;
[0014] Fig. 3 is a perspective schematic view of a liquid applying apparatus according to an alternate embodiment of the present invention;
[0015] Fig . 4 i s a s ide view of part of the apparatus of
Fig. 3, showing a feeder system thereof;
[0016] Fig. 5 is a block diagram of a control system of a liquid applying apparatus such as shown m Figs. 1-4 according to a particular embodiment of the present invention;
[0017] Fig. 6 is a block diagram of a tray control system of the system of Fig. 5 ;
[0018] Fig. 7 is a block diagram of a height control system of the system of Fig. 5;
[0019] Fig. 8 is a block diagram of a speed control system of the system of Fig. 5; and
[0020] Fig. 9 is a block diagram of a feeder control system of the system of Fig. 5;
[0021] Fig. 10 is a block diagram of a pattern control system of the system of Fig. 5; and
[0022] Fig. 11 is a block diagram of a safety system of the system of Fig. 5.
DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS
Drum embodiment
[0023] Referring to Fig. 1, a liquid applying apparatus 10 according to a particular embodiment of the present invention generally comprises a feeder system 12 picking up sheets 14 from a first pile, a receiver system 16 receiving the sheets 14 m a second pile, a rotating drum 18 transporting the sheets 14 from the feeder system 12 to the receiver system 16, and at least one array of fluid ejection heads 20 distributing a liquid, such as for example a coating liquid, on the sheets 14 while they are transported by the drum 18. [0024] Referring particularly to Fig. 2, the feeder system 12 comprises a tray system 38 including an angled bottom wall 40 supporting a pile of sheets 14, and spaced apart side walls 42 and an end wall 44 surrounding the sheets. The walls 42, 44 are preferably connected to appropriate driving means 46 such as to be able to accurately adjust the distance therebetween to correspond to a selected sheet size. The angled wall 40 is movable along a direction substantially perpendicular thereto through appropriate driving means 48 such as to be able to keep the topmost sheet of the pile at a substantially constant height .
[0025] Referring to Fig. 2, the feeder system 12 includes actuators 70 inclined with respect to the pile of sheets 14 and having flexible vacuum cups 74 at their lower end. The actuators 70 lower the vacuum cups 74 until they are compressed against the pile of sheets 14, in a beveled manner because of the inclination of the actuators 70. The vacuum system of the cups 74 is activated, attaching the top sheet 14 thereto. The actuators 70 lift the vacuum cups 74 to their topmost position, lifting the grabbed sheet, which becomes inclined when the vacuum cups 74 return to their non-beveled state. Adjacent air nozzles 82 blow air under the sheet 14 to help the separation of the sheet from the remaining pile. The actuators 70 are then moved downstream under the action of actuators 62 such that the end of the sheet 14 rests between spaced apart top and bottom rollers 58, 78. The top rollers 58 are moved against the bottom roller 78 by actuators 54, and the vacuum is released on the cups 74. The bottom roller 78 starts to turn, moving the sheet 14 along a slide plate 86 toward the drum 18. An end roller 88 rotates through contact with the drum 18, and presses the sheet 14 against the drum 18 as the sheet 14a leaves the slide plate 86 to be "grabbed" by the vacuum system of the drum 18. The top rollers 58 and actuators 70 are then returned to their original position and the bottom roller 78 stops rotating. [0026] Referring back to Fig. 1, the rotating drum 18 is adapted to retain sheets 14 of various sizes. The drum 18 includes a circumferential wall 94 and is rotationally received on a drum shaft 96. The circumferential wall 94 is engaged to a driving belt 102 which is engaged to a pulley 104, the pulley 104 being driven by a motor 106 or other appropriate driving means such as to rotate the drum 18 in a continuous manner. The circumferential wall 94 includes a plurality of holes (not shown) defined therethrough and is under vacuum such as to retain the sheets thereon.
[0027] The heads 20 are retained in a fixed manner over the drum, although in an alternate embodiment the heads 20 are movable. One or more array of heads 20 can be provided, such as for example to distribute different liquids. Each head 20 is equipped with an array of aligned, regularly spaced apart small nozzles (not shown) , each nozzle being controlled independently. The heads 20 are in fluid communication with a reservoir of liquid, which m a particular embodiment is a coating liquid, but can alternately be any other liquid adapted to be distributed by the heads 20 such as for example ink, adhesive, silicon release agent, conductive ink, etc.
[0028] Each nozzle can produce a small, precise jet of liquid depositing a single drop on the substrate. The heads 20 are selected according to the precision of the liquid pattern to be applied, with heads having smaller nozzles placed closer together providing a more precise distribution of the liquid.
[0029] In the case where the heads distribute a coating liquid, or a type of ink adapted to produce a variable gloss effect, various degrees of gloss can be obtained with a same liquid by varying at least one of the size of the liquid drop deposited by each nozzle and the distance between the drops deposited on the substrate (i.e. between subsequent firing nozzles) , before the liquid is cured. If necessary, once the liquid is cured, at least one other layer of liquid can be deposited thereover using a similar technique. For example, by depositing small drops of coating liquid which are spaced apart from each other, the coating obtained will have a mat finish. As the edge of deposited drops are closer together, whether by increasing the center to center distance between adjacent drops and/or the size of individual drops, the coating becomes progressively more glossy. When the adjacent drops are close enough to merge and form a continuous film, the coating obtained can take the form of a smooth, mirror-like glossy surface. This allows for the creation of a variation in gloss level for a same substrate or between subsequent substrates while using the same liquid, while allowing the creation of the smooth, mirror-like surface in a single pass, and without requiring the application of a film over the liquid during curing as in the case of many prior art methods .
[0030] Where required, a curing or drying apparatus 140 for the liquid is supported over the drum 18 downstream of the array of heads 20. In a particular embodiment, the liquid is a coating liquid curable through exposition to ultra-violet light, and as such the curing apparatus 140 includes one or more ultra-violet lamps (not shown) . Alternately, the liquid can be a solvent-based or a water- based fluid, and the apparatus 140 can include infra-red lamps, a micro-wave emitter, and/or any other type of appropriate curing or drying system.
[0031] The receiver system 16 includes a tray system 148 similar to that of the feeder system 12 described above, i.e. with a movable angled bottom wall 150, end wall 152 and parallel side walls 154, such as to receive and align the sheets 14 coming off of the drum 18. The receiver system 16 also includes a pivotable slide plate 156 for detaching the sheets 14 from the drum 18. The slide plate 156 is pivotable between a first position coming between the incoming sheet 14 and the drum 18 and a second position away from the drum 18 under the action of actuators 158.
[0032] Similar or equivalent mechanisms can also be provided at various points around the drum 18 such as to be actuated when a damaged sheet (for example a crumpled sheet or a double sheet) is present to remove that sheet from the drum 18, thus preventing the damaged sheet from damaging sensitive elements of the apparatus, for example the heads 20 or the curing/drying apparatus 140.
Conveyor embodiment
[0033] Referring to Fig. 3, a liquid applying apparatus 210 according to an alternate embodiment of the present invention is shown. The apparatus 210 generally comprises a feeder system 212 picking up sheets 14 from a first pile, a receiver system 216 receiving the sheets 14 in a second pile, a conveyor 218 transporting the sheets 14 from the feeder system 212 to the receiver system 216, and at least one array of fluid ejection heads 20 distributing liquid on the sheets 14 while they are transported by the conveyor 218.
[0034] Referring particularly to Fig. 4, the feeder system 212 comprises a tray 238 receiving a pile of sheets, with side walls 242 of the machine 210 (only one of which is shown) surrounding the pile of sheets 14. Centering guides 245 (see also Fig. 3) surround the front edge of the sheets 14, and the feeder 212 preferably includes means to adjust the distance therebetween such as to adjust to sheets of different sizes, as in the previous embodiment. The tray 238 is supported to be movable along a substantially vertical or vertical direction, through appropriate driving means 248, such as to be able to keep the topmost sheet of the pile at a substantially constant height.
[0035] The feeder system 212 includes vertical arm actuators 270, the bottom end 272 of each arm actuator 270 including a vacuum cup 274. The arm actuators 270 lower the vacuum cups 274 until they are compressed against the top sheet, and the vacuum system is activated to attach to top sheet to the vacuum cups 274. The arm actuators 270 are then tilted under the action of a tilt actuator 262, lifting the front edge of the sheet. The arm actuators 270 lift the vacuum cups 274 to their topmost position, lifting the grabbed sheet 14 from the pile. Air, which can be ionized, comes from front and rear air nozzles 282, 283 to facilitate the separation of the sheet from the remaining sheets 14. The arm actuators 270 are then rotated to their original vertical orientation by the tilt actuator 262, and moved downstream toward the conveyor 218 by a horizontal actuator 254, until the front end of the sheet rests between spaced apart top and bottom nip rollers 258, 278. The top nip roller 258 is then moved to press against the bottom nip roller 278, sandwiching the end of the sheet therebetween. The vacuum is released on the cups 274 and the bottom roller 278 starts to turn, moving the sheet 14 toward the conveyor 218. The sheet is then "grabbed" by the vacuum of the conveyor 218. The top nip roller 258 and arm actuators 270 are then returned to their original position, and the bottom roller 278 stops rotating.
[0036] Referring back to Fig. 3, the conveyor 218 is adapted to retain sheets 14 of various sizes. The conveyor 218 includes a conveyor belt 294 defining a support surface 300 for the sheets, which is preferably non-stick such as to facilitate clean-up in case of a spilling of liquid thereon. The conveyor belt 294 includes a series of holes 310 defined therethrough across the support surface 300. The conveyor 218 includes a downstream roller 305 driven by appropriate driving means 306 such as to rotate the conveyor belt 294 in a continuous manner. A vacuum system (not shown) creates a vacuum only in the top section of the conveyor belt 294. Thus, the sheets 14 are received and retained on the support surface 300 by the vacuum, and released when they arrive in proximity of the receiver system 216 where the conveyor belt 294 is no longer in communication with the vacuum system.
[0037] The heads 20 and curing or drying apparatus 140 are similar to the heads and curing or drying apparatus described in the previous embodiment, and as such will not be further described herein. [0038] The receiver system 216 includes a tray 348 similar to that of the feeder system 212 described above, with the sheets 14 being received on top of the bottom wall 350 and enclosed by side walls 354 of the machine. The receiver system 216 preferably includes centering guides (not shown) such as the centering guides 245 of the feeder system 212, with means to adjust the distance therebetween such as to adjust to sheets of different sizes. In the embodiment shown, the tray 348 is supported at a fixed height. However, the tray 348 can alternately be supported m a vertically movable manner, similarly to the tray 238 of the feeder system 212 described above.
[0039] Particular embodiments for each of the liquid applying machines 10, 210 are described in further detail in simultaneously filed PCT application No
entitled "APPARATUS APPLYING LIQUID TO A SURFACE", the specification of which is incorporated herein by reference m its entirety.
Control System
[0040] Referring to Fig. 5, both liquid applying machines 10, 210 are controlled by a control system, which comprises a mam controller 400 receiving data from a data entry module 402 and coordinating a tray control system 404, a safety system 406, a pattern control system 408, a feeder control system 410, a speed control system 412 and a height control system 414.
[0041] The data entry module 402 collects information from a user on the coating and/or printing and/or cutting operation (s) to be performed by the apparatus 10, 210, and sends this information to the mam controller 400 m the form of pattern data (including the position and thickness of the coating liquid/ink/cutting liquid to be applied) , desired speed data for the process, frequency data (i.e. spacing between consecutive sheets) sheet size data, user correction data (containing register corrections entered manually by the user) , etc. The data entry module 402 also sends an actuation signal to the controller when the user has indicated, for example by pressing a button, that the process can begin.
[0042] The data entry module 402 can take the form, for example, of a user interface such as a keyboard or any other source of commands, or receive data from a portable medium connected thereto. For example, the pattern data and sheet size data can be stored onto a portable medium, and the desired speed data, frequency data and user correction data can be created upon actuation by the user of a user interface. For example, if the user wants to change the position of the pattern on the sheet with respect to the original pattern, the position corrections can be indicated through the user interface, which creates the user correction data accordingly. The data entry module can also receive a feedback signal from the main controller 400, which allows it to display information on the process for the user.
[0043] Referring to Figs. 5 and 6, the main controller 400, upon reception of the data from the data entry module 402, sends the sheet size data to the tray control system 404, more specifically to a tray controller 416. The tray controller 416 receives position data from sensors 418 of the walls or centering guides 42, 44, 245, 152, 154 of the feeder systems 12, 212 and receiver systems 16, 216, and actuates the motors or other driving means 46 (shown for the apparatus 10 m Fig. 1) of the walls or guides until the position data received corresponds to the sheet size data. The main controller 200 can also send a signal instructing the tray controller 416 to oscillate, jog or vibrate the walls or centering guides 42, 44, 245, 152, 154 through appropriate actuation of the motors 46, such as to facilitate stacking of the sheets 14 m an aligned manner. The tray controller 416 sends a status signal to the main controller 400 to indicate whether the position of the walls or centering guides 42, 44, 245, 152, 154 is adequate. [0044] In an alternate embodiment, the feeder systems 12, 212 and receiver systems 16, 216 have trays with non-movable walls or centering guides, and the tray controller 416 is omitted .
[0045] Referring to Figs. 5 and 7, the main controller 400 also sends an actuation signal to the height control system 414, more specifically to a height controller 420. The height controller 420 receives height data from a sheet height sensor 422 (see also Figs. 2 and 4) , which is located m the feeder system 12, 212 over the pile of sheets 14 to determine the height of the topmost sheet of the pile 14. In a particular embodiment, the sheet height data includes an actual distance between the sensor 422 and the topmost sheet, and the height controller 420 compares the sheet height data received to a reference value and activates the motor or other driving means 48, 248 (see also Figs. 1 and 4) moving the bottom wall 40, 240 of the feeder system 12, 212 until the sheet height data corresponds to the reference value. The height sensor 422 can alternately or additionally (e.g. as a fail-safe mechanism) include a switch 423 (see Fig. 4) , and the sheet height data includes a signal from the switch 423 (producing an actuation signal when the topmost sheet is at the appropriate height and actuates the switch 423) such that the height controller 420 activates the motor or other driving means 48, 248 moving the wall up 40, 240 until that actuation signal is received. The sheet height controller 420 sends a status signal to the main controller 400 so as to indicate whether the sheet height is adequate. The height controller 420 regulates the sheet height throughout the entire liquid application process.
[0046] Referring to Figs. 5 and 8, the main controller 400 sends the desired speed data to the speed control system 412, more particularly to a speed controller 424. The speed controller 424 receives real speed data from a speed sensor 426 (see also Figs. 1 and 3) , which measures the speed of rotation of the drum 18 or conveyor 218. In a particular embodiment, the speed sensor 426 is an encoder contacting the circumferential wall 94 or conveyor belt 294 in proximity of the heads 20. The speed controller 424 actuates the drum or conveyor driving means 106, 306 (see Figs. 1 and 3) and regulates the speed thereof so as to match the real speed data as closely as possible with the desired speed data. The speed controller 424 sends the real speed data to the main controller 400.
[0047] Referring to Figs. 5 and 9, the main controller 400 sends the real speed data and frequency data to the feeder control system 410, more particularly to a feeding controller 428. The feeding controller 428 actuates a motor 430 (or other driving means) rotating the bottom roller 78, 278 and the actuators of the feeder system 12, 212 (such as 54, 62, 70, 254, 262, 270 of Figs. 2 and 4) such that the motions of the vacuum cups 74, 274 and top rollers 58, 258 as well as the rotation of the top rollers 78, 278 are coordinated both with each other and with the real speed of the drum 18 or conveyor 218. The actuators 54, 62, 70, 254, 262, 270 and motors 430 send feedback signals to the feeding controller 428. The feeding controller 428 sends a status signal to the main controller 400 indicating that the feeder system 12, 212 is operating.
[0048] Referring to Figs. 5 and 10, the main controller 400 sends the sheet size data, user correction data, pattern data and real speed data to the pattern control system 408, more particularly to a pattern controller 432. The pattern controller 432 sends the pattern data to a firing pattern calculator 434, which establishes a firing pattern for the nozzles of the heads 20 according to the pattern data. The firing pattern calculator 434 sends firing pattern data to the pattern controller 432, indicating which nozzles should be fired for each line of the pattern. The firing pattern data is calculated based on a reference position, for example with the sheet being perfectly aligned with the direction of travel and in the exact center of the array of heads . [0049] Although the pattern data has been described as being provided by the user, alternately the system includes a bar code reader (not shown) which reads a bar code on the substrate upstream of the heads 20, and the main controller 400 selects the pattern data from a list according to the bar code read. Alternately, the bar code could also be used as a confirmation of the pattern data provided by the user.
[0050] The pattern controller 432 also sends the sheet size data and the user correction data to an offset calculator 436. The offset calculator 436 receives position data from at least one sheet position sensor 438 (see also Figs. 1 and 3) . The• sheet position sensor 438, which can be for example an ultrasonic sensor, infrared sensor, laser sensor or CCD sensor, is retained over the drum 18 or conveyor 218 upstream of the array of coating heads 20. The sheet position sensor 438 indicates through the position data the position of the sheet 14, for example by detecting the front edge of the sheet 14 or a specific printed pattern or target (whether printed or else, such as for example the presence of glitter material) on the sheet 14. When more than one such sensors 438 are used, the position data can include a lateral position of the sheet (i.e. a position of the sheet in a direction perpendicular to the direction of travel) and a skew of the sheet 14, i.e. how much the sheet 14 is turned with respect to the direction of travel.
[0051] The offset calculator 436 thus calculates, based on the position data, the relative position of the sheet 14 with respect to the reference position, and calculates a necessary offset to be applied to the firing pattern data. The offset calculator 436 also adds the user correction data (if any is provided) to the offset calculated, and then sends corresponding offset data to the pattern controller 432.
[0052] The pattern controller 432 calculates a longitudinal register delay between the sheet 14 passing under the sheet position sensor 438 and the actuation of the heads 20 based on the real speed data. After the longitudinal register delay, the pattern controller 432 actuates the nozzles of the heads 20 following the firing pattern data but offset m accordance with the offset data to perform a lateral and skew register for the sheet 14, a delay between each line of the pattern being selected according to the real speed data. This allows for the liquid to remain m register with the sheets even when successive sheets are not perfectly aligned.
[0053] The pattern controller 432 thus applies the same firing pattern data to all the sheets following successive offset data which vary from one another in lateral and/or skew register. As such, the firing pattern data is not changed but rather the position where it is applied is moved by a given increment, simply by applying this increment to the nozzle selection. As such, corrections can be performed quickly without recalculating the firing pattern data and without the need to re-rip the source image of the pattern, thus without the need for access to the source image and/or the software used to create it. The quick corrections substantially reduce waste material produced when adjusting the register of the coating pattern with the sheets and eliminate the time which would otherwise be necessary to re- rip the source image m between corrections.
[0054] For example, the nozzles of the heads 20 can be subsequently numbered in relation to their relative position, and as such the firing pattern data includes a series of numbers representing the nozzles to be fired to obtain the desired pattern, with optionally a drop size associated with each nozzle. The offset data includes an operation to be performed to the number sequence representing the nozzle selection, corresponding to the difference between the relative position of the sheet 14 with respect to the reference position, such as a translation of a given number of nozzles m a given direction. The pattern controller 272 thus performs this operation on the firing pattern data to obtain a corrected pattern data which is used to actuate the corresponding nozzles of the heads 20.
[0055] When the pattern data requires a second pass or more passes of the sheet 14 under the heads 20, the pattern controller 432 sends a second pass signal to the main controller 400, which m turn will indicate to the feeder control system 410, through the frequency data, that no sheet should be fed. In the case of the apparatus 10, the pattern controller 432 also actuates the actuator 158 of the slide plate 156 of the receiver system 16 (see Fig. 1) such that the slide plate 156 moves away from the drum 18, allowing the sheet 14 to remain on the drum 18 for a second pass. Although not shown, in the case of the apparatus 110, the pattern controller 432 or main controller 400 can actuate the driving means 306 of the conveyor 318 such that the conveyor 318 backs up to bring the sheet back under the heads 20.
[0056] Referring to Figs. 5 and 11, the main controller 400 sends the real speed data to the safety system 406, more particularly to the safety controller 440. The safety controller 440 receives data from a crumpled sheet sensor 442, a sheet quantity sensor 444 and a sheet presence sensor 446.
[0057] Referring to Figs . 2 and 3 , the crumpled sheet sensor 442 is retained just downstream of the feeder system 12, 212. In a particular embodiment, the crumpled sheet sensor 292 is composed of two receiving units placed on one side of the circumferential wall 94 or the conveyor belt 294, and two emitting units placed on the other side of the circumferential wall 94 or the conveyor belt 294 and aligned with the receiving units. Each emitting unit sends an infrared beam to a corresponding one of the receiving units, the two beams crossing each other at a given distance above the circumferential wall 94 or the conveyor belt 294. Referring to Fig. 10, if a sheet has a crumpled corner, the crumpled corner interrupts at least one of the infrared beams, and the crumpled sheet sensor 442 sends a crumpled sheet signal to the safety controller 440. A similar crumpled sheet sensor can also be provided downstream of the curing/drying apparatus 140 (not shown) or at any other appropriate location .
[0058] Referring to Figs. 2-4, the sheet quantity sensor 444 is retained just downstream of the feeder system 12, 212, before the sheet engages the drum 18 or conveyor 218. The sheet quantity sensor 444 is for example an ultrasonic sensor which can detect if a single or multiple sheets are being fed to the drum 18 or conveyor 218. Referring to Fig. 11, upon detection of a single or multiple sheets, the sheet number sensor respectively sends a single sheet signal or multiple sheet signal to the safety controller 440.
[0059] Referring to Figs. 1 and 3, the sheet presence sensor 446 is retained over the drum 18 or conveyor 218 downstream of the curing/drying apparatus 140. Referring to Fig. 11, the sheet presence sensor 446 detects the presence of a sheet exiting from the curing/drying apparatus 140, and sends a sheet presence signal to the safety controller 440.
[0060] The safety controller 440, upon receiving a crumpled sheet signal or a multiple sheet signal, actuates the appropriate ejection mechanism 450 (which can be for example similar to the slide plate 156 of the receiver system 16 of the apparatus 10) to remove the crumpled sheet or multiple sheets from the drum 18 or conveyor 218. Also, upon reception of the single sheet signal, the safety controller 440 calculates, based on the real speed data, an expected delay between the reception of the single sheet signal (i.e. sheet exiting the feeder 12, 212) and the reception of the sheet presence signal (i.e. sheet exiting the curing/drying apparatus 140) . If the safety controller 440 has not received the sheet presence signal within the expected delay, then the sheet must be stuck somewhere, potentially under the curing/drying apparatus 140 where it can become a fire hazard. The safety controller 440 thus sends a status signal to the main controller 400 which stops the process so that the stuck sheet can be removed. The main controller 400 or safety controller 440 can also activate other types of safety mechanisms, such as for example the closing of a shutter (not shown) on the curing or drying apparatus 140 to reduce the risk of fire.
Alternate Embodiments
[0061] Alternately, the drum 18 or conveyor 218 can be replaced by other equivalent means of moving sheets 14, or by means of moving a paper web, such as for example a series of rollers driving the web to and from the heads 20. Moreover, the heads 20 can be used to apply liquid to either sheets or web on both sides thereof, for example by having one or more series of heads 20 installed on each side of a web being driven by a series of rollers.
[0062] Further, the heads 20 can be installed on a movable support actuated by the pattern controller 432 to move the heads 20 according to the pattern data. In this case, the sheet can be in a fixed position during the coating process, if the moveable support is moveable along the entire surface of the sheet. The sheet can alternately be incrementally moved in a first direction, the heads being moved in a second direction perpendicular to the first one between each increment of the movement of the sheet, using a mechanism similar to that of a desktop inkjet printer. In both cases, a single head could be used instead of the array of heads 20.
[0063] Preferably, the distance between the heads 20 and the drum 18 or conveyor 218 can be adjusted, such as to obtain an optimal distance between the substrate and heads 20, for example lmm, regardless of the thickness of the substrate .
[0064] The apparatus 10, 210 can have multiple arrays of heads 20 such as to apply a same or a different liquid to the substrate. In this case, one or more sheet position sensor (s) 438 can be provided upstream of each array of heads such as to detect the precise position of the sheet, and send a signal to a respective pattern control system accordingly. Each pattern control system, similar to the pattern control system 408 described above, creates a firing pattern data based on the particular pattern data for the corresponding array of heads, and offset data based on the corresponding user correction data and sheet position data.
[0065] As such, since corrections to the register of all the operations can be performed independently, without the need to move the sheet (or web) , the overall register can be quickly adjusted before application of the liquid (s) on the substrate without the need to re-rip the source image of the pattern, reducing waste generated by the production of the finished product. Also, since all the operations are digital, the pattern of one or all the operations can easily be changed without the need to change a physical element of the machine, which greatly simplifies the necessary preparation between the production of two different finished products. Moreover, the apparatus 10, 210 can effectively produce a series of proofs that correspond perfectly to the finished product, as proofs and finished product are produced by a same machine.
[0066] The apparatus 10 can advantageously be used in line with other paper or web processing machines, for example with a printing machine producing printed sheets that are usually disposed in a stack at the exit point of the printing machine. A conveyor or similar sheet transporting means can be provided at the exit point to intercept the printed sheets and transport them to the apparatus 10, for example to the tray system 38 of the feeder system 12, where the sheets are picked up and placed on the drum 18, coated by coating liquid applied by the heads 20, cured by the curing apparatus 140 and stacked by the receiver system 16, as described above. Similarly, the apparatus 210, without the feeder system 212 and receiver system 216, can be installed in line with a printing machine, the sheets exiting the printing machine directly onto the conveyor 218 to be coated by the heads 20, and/or in line with a cutting machine, the sheets exiting the conveyor 218 to be picked up by the cutting machine. As such, the time and labor necessary to transport the sheets from one machine to the apparatus 10, 210 are saved.
[0067] The embodiments of the invention described above are intended to be exemplary. Those skilled in the art will therefore appreciate that the foregoing description is illustrative only, and that various alternate configurations and modifications can be devised without departing from the spirit of the present invention. Accordingly, the present invention is intended to embrace all such alternate configurations, modifications and variances which fall within the scope of the appended claims.

Claims

CLAIMS :
1. A system for registering a pattern of liquid to be applied by fluid ejection heads on a moving substrate, the system comprising:
a firing pattern calculator adapted to receive pattern data corresponding to the pattern of liquid to be applied on the substrate, and to generate firing pattern data corresponding to a firing sequence of the fluid ejection heads to obtain the pattern of liquid on the substrate when the substrate is in a reference position with respect to the fluid ejection heads;
a speed sensor sensing a speed of the moving substrate and producing corresponding speed data;
at least one position sensor sensing an actual position of the substrate upstream of the fluid ejection heads and producing corresponding position data;
an offset calculator adapted to receive the position data from the position sensor and to generate offset data corresponding to a difference in the firing sequence brought by a difference between the actual position of the substrate and the reference position; and
a controller adapted to receive the speed data, and to determine a register delay and a line delay using the speed data, the register delay corresponding to a time of a first actuation of the fluid ejection heads and the line delay corresponding to a time between an application of a line and a subsequent line of the pattern of liquid, the controller actuating the fluid ejection heads after the register delay based on the offset data and line delay applied to the firing pattern data.
2. The system according to claim 1, wherein the offset calculator also receives user correction data corresponding to an additional offset of the pattern provided by the user, and the offset data corresponds to a total offset determined based on the position data and the user correction data.
3. The system according to claim 1 or 2, wherein the position data includes a position of the substrate in. a direction perpendicular to a direction of travel thereof and a skew of the substrate with respect to the direction of travel .
4. The system according to any one of claims 1 to 3 , wherein the liquid is one of a coating liquid, an ink, an adhesive and a silicon release agent.
5. The system according to any one of claims 1 to 4 , wherein each of the fluid ejection heads includes a series of nozzles, the firing sequence of the firing pattern data including a sequence of nozzles to be fired for each line of the pattern of liquid to be applied on the substrate.
6. The system according to claim 5, wherein the firing pattern data also includes a size of a drop to be deposited by each of the nozzles being fired m accordance with the firing sequence.
7. The system according to any one of claims 1 to claim 6, wherein the pattern data includes a distribution and a thickness of the liquid to be applied across a surface of the substrate.
8. A method of registering a pattern of a liquid to be applied on a moving substrate by an array of ejection heads, the method comprising:
determining a desired pattern of the liquid on the substrate ;
determining a firing pattern of the ejection heads based on the desired pattern, the firing pattern corresponding to the substrate being m a reference position;
detecting a position of the substrate upstream of the ejection heads;
determining a difference between the position of the substrate and the reference position;
determining an offset to be applied to the firing pattern corresponding to the difference between the position of the substrate and the reference position; applying the offset to the firing pattern to obtain a corrected firing pattern; and
actuating the ejection heads according to the corrected firing pattern.
9. The method according to claim 8, wherein each of the ejection heads includes a plurality of nozzles, and determining the firing pattern includes determining which nozzles of each of the ejections heads is fired for each line of the desired pattern.
10. The method according to claim 9, wherein the nozzles of all ejection heads are numbered sequentially with respect to a relative position thereof, the firing pattern data corresponding to a sequence of nozzle numbers, and determining an offset includes determining an operation to be performed on the sequence of nozzle numbers of the firing pattern data.
11. The method according to any one of claims 8 to 10, wherein the desired pattern is determined to include a distribution of the liquid across a surface of the substrate and a varying thickness of the liquid m different regions of the distribution.
12. The method according to any one of claims 8 to 11, wherein determining the position of the substrate includes determining a lateral position of the substrate m a direction perpendicular to a direction of travel thereof and a skew of the substrate with respect to the direction of travel .
13. The method according to any one of claims 8 to 12, wherein determining the offset to be applied to the firing pattern includes combining the difference between the position of the substrate and the reference position and a user correction data provided by a user and corresponding to a desired offset of the pattern with respect to the reference position.
14. The method according to any one of claims 8 to 13, wherein the position of the substrate is detected by detecting a location of a downstream edge of the substrate.
15. The method according to any one of claims 8 to 13, wherein the position of the substrate is detected by detecting a location of a specific target on the substrate.
16. A method of producing at least one desired gloss level on a substrate, comprising:
selecting the at least one desired gloss level for the substrate;
depositing an uncured liquid on the substrate in a plurality of drops to form a pattern of the uncured liquid, at least one of a size of the drops and a distance between adjacent drops being selected according to the desired gloss level; and
curing the liquid.
17. The method according to claim 16, wherein selecting the at least one desired gloss level includes selecting a first gloss level for a first region of the substrate and a second gloss level for a second region of the substrate, and depositing the uncured liquid includes selecting at least one of a different drop size and a different distance between adjacent drops for the first and second regions.
PCT/CA2006/002014 2005-12-09 2006-12-11 Control system for liquid applying apparatus WO2007065275A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114555371A (en) * 2019-10-11 2022-05-27 3M创新有限公司 Ink jet printing method and ink jet printing apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2353863B1 (en) 2010-02-02 2016-03-30 Komori Corporation Printing/coating method and apparatus
DE102019122839A1 (en) * 2019-08-26 2021-03-04 Miva Technologies Gmbh Method and exposure device for exposing a light-sensitive recording medium

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62111775A (en) * 1985-11-09 1987-05-22 Matsushita Electric Ind Co Ltd Printing position automatic calculator
EP0884191A2 (en) * 1997-06-09 1998-12-16 Hewlett-Packard Company Method and apparatus for improving ink-jet print quality using a jittered print mode
WO1999054142A1 (en) * 1998-04-23 1999-10-28 Stork Digital Imaging B.V. Method and device for monitoring and/or correcting the alignment of an ink-jet printer
US6398332B1 (en) * 2000-06-30 2002-06-04 Silverbrook Research Pty Ltd Controlling the timing of printhead nozzle firing

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1110375A (en) * 1978-12-11 1981-10-06 Vincent D. Mcginniss Ultraviolet curable powder paints
US4421784A (en) * 1982-02-12 1983-12-20 Union Carbide Corporation Process for producing textured coatings
US5959306A (en) * 1996-02-08 1999-09-28 Bright Solutions, Inc. Portable light source and system for use in leak detection
DE10012580A1 (en) * 2000-03-15 2001-09-27 Basf Coatings Ag Photoinitiator free (meth)acrylate copolymer based coating agent, adhesive or sealant, comprises a (meth)acrylate copolymer or a compound that is activated by actinic radiation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62111775A (en) * 1985-11-09 1987-05-22 Matsushita Electric Ind Co Ltd Printing position automatic calculator
EP0884191A2 (en) * 1997-06-09 1998-12-16 Hewlett-Packard Company Method and apparatus for improving ink-jet print quality using a jittered print mode
WO1999054142A1 (en) * 1998-04-23 1999-10-28 Stork Digital Imaging B.V. Method and device for monitoring and/or correcting the alignment of an ink-jet printer
US6398332B1 (en) * 2000-06-30 2002-06-04 Silverbrook Research Pty Ltd Controlling the timing of printhead nozzle firing

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114555371A (en) * 2019-10-11 2022-05-27 3M创新有限公司 Ink jet printing method and ink jet printing apparatus
US20220371335A1 (en) * 2019-10-11 2022-11-24 3M Innovative Properties Company Inkjet printing method and inkjet printing device
CN114555371B (en) * 2019-10-11 2024-04-05 3M创新有限公司 Inkjet printing method and inkjet printing apparatus

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