EP1302316A2 - Chambered doctor blade - Google Patents

Chambered doctor blade Download PDF

Info

Publication number
EP1302316A2
EP1302316A2 EP20020445124 EP02445124A EP1302316A2 EP 1302316 A2 EP1302316 A2 EP 1302316A2 EP 20020445124 EP20020445124 EP 20020445124 EP 02445124 A EP02445124 A EP 02445124A EP 1302316 A2 EP1302316 A2 EP 1302316A2
Authority
EP
European Patent Office
Prior art keywords
doctor blade
chambered doctor
cylinder
force
force means
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP20020445124
Other languages
German (de)
English (en)
French (fr)
Inventor
Ake Bööse
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ake Boose Utvecklings AB
Original Assignee
Ake Boose Utvecklings AB
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 Ake Boose Utvecklings AB filed Critical Ake Boose Utvecklings AB
Publication of EP1302316A2 publication Critical patent/EP1302316A2/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F31/00—Inking arrangements or devices
    • B41F31/02—Ducts, containers, supply or metering devices
    • B41F31/027—Ink rail devices for inking ink rollers

Definitions

  • the present invention relates to an arrangement for a chambered doctor blade intended for a printing unit.
  • the invention also concerns a chambered doctor blade provided with at least one such arrangement and a printing unit provided with one such chambered doctor blade arrangement.
  • Chambered doctor blades are extensively used in rotary-printing units, especially flexo-printing units, for applying ink, lacquer, adhesive or the like to a rotatable cylinder included in the printing unit.
  • a screen roller is used as inking roller.
  • This roller or cylinder has on its circumferential surface recesses/cells that are evenly distributed across generally the whole circumferential surface.
  • the screen roller By causing the screen roller to run in contact with printing ink that is often of low viscosity, the cells are filled with printing ink, whereupon excess ink is scraped or wiped off by means of a doctor blade which abuts against the roller. A layer of evenly distributed ink is then transferred from the thoroughly wiped screen roller to a soft high-intensity printing form, the flexographic printing plate.
  • a chambered doctor blade which per se functions well, is known, inter alia, from WO 93/24328.
  • a chambered doctor blade of this kind has the form of an elongate inking container or inking chamber which is arranged horizontally and abuts against the screen roller and which has an upper and a lower doctor blade as well as end seals at both ends of the chamber.
  • the doctor blades (lamellae) and the end seals form a close-fitting frame against the circumferential surface of the screen roller.
  • the chambered doctor blade which during printing is filled with ink, is applied against the rotating screen roller, which causes the cells of the roller to be filled with ink.
  • the function of each doctor blade changes with the direction of rotation of the roller.
  • the screen roller In order for the screen roller to deliver a predetermined quantity of ink during the entire printing, its circumferential surface has to be wiped in a constant manner. Thus, the doctor blades must abut against the screen roller with a predetermined minimum abutment pressure.
  • the main part of the application force is absorbed by adjusting screws (reference numeral 37), and thus only a small part of the total application force is used to apply the doctor blades against the screen roller.
  • the adjusting screws are adjusted manually when positioning new doctor blades with respect to their parallelism with the roller and their abutment pressure against said roller.
  • a manual correction of the position of the chamber in relation to the screen roller is carried out occasionally during printing by regulating the adjusting screws. This allows a lower application pressure to be used.
  • the object of the present invention is to provide an improved arrangement for use in connection with a chambered doctor blade in a printing unit, which arrangement completely or partly obviates the above drawbacks associated with prior-art technique.
  • the force by which the chambered doctor blade is applied against the roller can be optimized without the need for time-consuming manual adjustments.
  • An optimal application force means that an adequate quantity of ink is delivered from the screen roller and unnecessary misprints are thus avoided.
  • the wear of the doctor blades and end seals is reduced. Fewer doctor blades and end seals are thus required, which implies lower costs. Less wear also implies lower costs since the machine downtime required to change the doctor blades and seals will be reduced.
  • the second force means is adjustably arranged on a rack which is movable relative to the fixed parts of the printing unit and adapted to absorb at least part of the force exerted by the first force means, to allow a first initial positioning of the second force means when the doctor blade is being applied against the roller in an operative position.
  • the second force means may be a threaded element adapted to absorb considerable forces.
  • One advantage of using a pneumatic cylinder as feeding device is that it is a simple, 'clean' and inexpensive solution.
  • a chambered doctor blade provided with at least one inventive arrangement offers the advantage of allowing automatic, parallel adjustment.
  • the advantages of a corresponding printing unit follow from that stated above.
  • Fig. 1 shows a chambered doctor blade device 1 according to prior-art technique and parts of the printing unit in which the chambered doctor blade 1 is included.
  • the chambered doctor blade 1 comprises an elongate frame 2, on which two parallel, elongate doctor blades 3, 4 are mounted at a distance from each other and parallel to the frame 2.
  • the chambered doctor blade 1 is arranged parallel to and adjacent a cylinder 5 included in the printing unit in such manner that the doctor blades 3, 4 abut against the circumferential surface of the cylinder 5.
  • the frame 2 of the chambered doctor blade 1 and the doctor blades 3, 4 define, together with the circumferential surface of the cylinder 5 and end seals (not shown) provided at the ends of the chambered doctor blade 1, an elongate chamber K holding printing ink or the like to be applied to the cylinder 5.
  • the chambered doctor blade 1 is supported on guides 7 (only one is shown) which are movable in relation to the fixed parts 6 of the printing unit.
  • the chambered doctor blade 1 may be moved to its operative position and applied against the cylinder 5 by the force exerted by a first force means comprising, for example, a spring, such as a gas spring 8 arranged on the guide 7.
  • an adjustable stop means or force-absorbing means 9 is provided at each end of the supporting system of the chambered doctor blade 1.
  • said means comprises an adjusting screw 9, which is received in a rack 10 that is fixedly connected to the guide 7 and in a bore in said guide 7.
  • the directions in which the guide 7 can move are indicated in the Figures by two-way arrows.
  • the rack 10 and the screw 9 are movable together with the guide 7 as a single unit to allow the chambered doctor blade 1 to be moved to its operative position.
  • the screw 9 is provided with a toothed wheel 12, which is non-rotationally mounted on the screw 9.
  • a piston-cylinder assembly 13 is mounted adjacent to the wheel 12.
  • the assembly 13 may be, for example, a single-acting pneumatic cylinder.
  • the cylinder 13 is provided with an arm or tongue 14 which can engage the wheel 12.
  • the arm 14 is flexible and may also be L or T shaped to obtain reliable operation of the arm 14. With each active stroke of the pneumatic cylinder 13, which causes its arm 14 to make contact with the cogs of the wheel 12, the wheel 12 rotates by one cog in its forward direction and the position of the screw 9 is changed so that the guide 7 can move towards the cylinder 5.
  • the length of stroke of the arm 14 exceeds the 'length' of one cog (cf. the spacing dimension of the wheel 12) and allows the wheel 12 to move freely, when the arm 14 is in its inoperative position, to enable manual adjustment of the screw 9 in both directions.
  • the chambered doctor blade 1 is moved less than one tenth of a millimeter closer to the screen roller 5 with each stroke of the cylinder 13.
  • the cylinder returns to its inoperative position. In this position, the wheel 12 can be rotated manually in both directions.
  • the cylinder 13 can only turn the wheel 12 in one direction, i.e. in the direction in which the chambered doctor blade 1 is applied against the screen roller 5.
  • a wheel 12 with asymmetric cogs is shown in Fig. 3.
  • a wheel 12 with symmetric cogs could also be used, but another angle of impact of the arm 14 would then be required.
  • the cylinder 13 can be controlled completely automatically with the aid of a counting unit (not shown) which receives pulses from, for example, an inductive sensor arranged adjacent to the rotating parts of the printing unit, such as a back-pressure cylinder. For instance, one complete turn may generate one pulse.
  • the counter (not shown) provides an output signal to an electrically operated pneumatic valve (not shown), and compressed air is then admitted, for example, for one second so that compressed air is supplied to the cylinder 13 by the intermediary of a compressed-air line 15.
  • the compressed air is then evacuated from the compressed-air line 15 and the cylinder 13, which is a single-acting, compressed-air cylinder of spring pull-back type, returns to its inoperative position. With each stroke of the cylinder 13, the wheel 12 rotates by one cog.
  • the number of pulses required for the counter to provide an output signal to the pneumatic valve can be set by the operator.
  • the operator chooses the number taking into consideration the type of ink, screen roller and doctor blades with which the printing unit concerned is equipped. The operator may change the chosen number of pulses at any time.
  • the arrangement of the invention allows manual adjustment of the application of the chambered doctor blade 1 against the screen roller 5 in each printing unit, since the screws 9 can be adjusted in both directions when the cylinders 13 are located in their inoperative positions.
  • Figs 4 and 5 illustrate a second embodiment according to which a free wheel hub 16 with cogs/teeth along its circumference has been mounted on the screw 9 and is adapted to be advanced by means of a gear rack 17 for adjusting the screw 9.
  • the inoperative position of the gear rack 17 is such as to allow manual adjustment of the screw 9 in both directions.
  • the arrangement may be used in a simpler form, in which the operator replaces the counter and instead activates a pneumatic valve in order to control the cylinders from a distance.
  • This allows the operator to influence the application of the chambered doctor blade against the cylinder in a certain printing unit from a distance without having to climb up to the printing unit concerned to physically adjust the screw 9, as is the case when using manual adjustment.
  • the cylinder 13 provided with the arm 14 can be replaced by a step motor (not shown).
  • the step motor should be disconnectable to allow manual adjustment of the screw 9 in both directions. This is achieved by a step motor which does not use hold current.
  • the wheel 12 may be replaced by a free wheel hub provided with a lever (not shown).
  • the lever should be disengageable to allow manual adjustment of the screw 9 in both directions.
  • inventive arrangement may also be used to apply single doctor blades against a cylinder.

Landscapes

  • Inking, Control Or Cleaning Of Printing Machines (AREA)
  • Screen Printers (AREA)
  • Rotary Presses (AREA)
EP20020445124 2001-10-04 2002-10-04 Chambered doctor blade Withdrawn EP1302316A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0103315 2001-10-04
SE0103315A SE518626C2 (sv) 2001-10-04 2001-10-04 Anordning vid kammarrakel samt kammarrakel och tryckverk med minst en sådan kammarrakel

Publications (1)

Publication Number Publication Date
EP1302316A2 true EP1302316A2 (en) 2003-04-16

Family

ID=20285555

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20020445124 Withdrawn EP1302316A2 (en) 2001-10-04 2002-10-04 Chambered doctor blade

Country Status (2)

Country Link
EP (1) EP1302316A2 (sv)
SE (1) SE518626C2 (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115447275A (zh) * 2022-10-14 2022-12-09 青岛嘉泽包装有限公司 可横向串动的胶印机涂布单元腔式刮刀及其刮料方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115447275A (zh) * 2022-10-14 2022-12-09 青岛嘉泽包装有限公司 可横向串动的胶印机涂布单元腔式刮刀及其刮料方法
CN115447275B (zh) * 2022-10-14 2023-12-15 青岛嘉泽包装有限公司 可横向串动的胶印机涂布单元腔式刮刀及其刮料方法

Also Published As

Publication number Publication date
SE0103315D0 (sv) 2001-10-04
SE0103315L (sv) 2002-10-29
SE518626C2 (sv) 2002-10-29

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SK TR

AX Request for extension of the european patent

Extension state: AL LT LV MK RO SI

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20050503