Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F13/00—Common details of rotary presses or machines
  • B41F13/02—Conveying or guiding webs through presses or machines
  • B41F13/025—Registering devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F13/00—Common details of rotary presses or machines
  • B41F13/08—Cylinders
  • B41F13/24—Cylinder-tripping devices; Cylinder-impression adjustments
  • B41F13/26—Arrangement of cylinder bearings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F5/00—Rotary letterpress machines
  • B41F5/24—Rotary letterpress machines for flexographic printing

Definitions

• the subject of the present invention is a device for adjusting the contact pressure between an inked plate roller and a movable strip of paper in line with a pressure roller in a flexographic printing machine.
• Flexographic printing machines generally comprise a plurality of successive printing groups, identical in their arrangement and in their operation, the printing plate and the ink color being only modified from one group to another.
• a strip of paper passes through each of the groups successively.
• Each group is made up of:
• - Inking means comprising an inkwell containing the liquid ink, a first bubbling roller which agitates the ink and a second ink roller known as "anilox".
• - Printing means proper which comprise a plate-carrying roller on which is placed the plate which reproduces the pattern to be printed.
• This cliché roller is movable in vertical translation to come into contact with the anilox along a generator, which causes the cliché to be inked. This adjustment is very delicate because the two rollers placed too close cause too much ink deposition, the two rollers arranged too far apart lead to ink defects.
• - means for guiding the paper strip comprising at least one input roller, one pressure roller, one tension roller and one output roller so that the four rollers are arranged at the vertices of a substantially rectangular quadrilateral, so preferential.
• the pressure roller is designed to receive the plate roller in support in order to deposit the ink following the pattern of the plate on the paper strip and the middle tension roller has a complementary guiding role.
• English patent GB-A-817,472 describes a printing unit in which there is a strip of paper plated on a tension roller mounted at the end of an arm movable in rotation about an axis disposed at the other end of this arm.
• the plate roller is also carried by the end of a movable arm rotating at its other end.
• the transfer key on the paper is thus adjustable.
• the ink take-up key As for the ink take-up key, it is adjusted by means of a set of two rollers, the first intermediate roller being fixed in translation and in contact with the printing plate roller and the second water roller being adjustable and immersed in the inkwell which thus ensures the transfer of an ink film of adjustable thickness on the first intermediate roller.
• the present invention provides an adjustment device which overcomes the drawbacks of the prior art, which allows very precise adjustments of the keys on each of the groups during operation while retaining the timing of the different groups with respect to the strip, which is simple which makes it reliable and leads to a low cost price and which is adaptable to certain existing machines.
• the device for adjusting a group of a flexographic printing machine which comprises at least two, according to the invention, each group comprising a continuous strip of paper, ten ⁇ due, circulating successively in each of the grou ⁇ pes, inking means with an inkwell, an ink roller, printing means with at least one movable plate roller in vertical translation intended to cooperate by contact with the ink roller, means guiding the strip of paper to be printed with at least one upstream tension roller, a pressure roller, a middle tension roller and a downstream tension roller, defining an upstream strand and a downstream strand, a first point of tangency between the upstream strand and the upstream tension roller, a second point of tangency between this upstream strand and the pressure roller, a third point of tangency between the middle tension roller and the downstream strand, and a fourth point of tangency between the downstream strand and the roller downstream tensioner, the pressure roller being pre ⁇ seen to cooperate with the plate-carrying roller and mounted on a mov
• the axis of rotation of the pressure roller is mounted movable in trans ⁇ lation along a straight line parallel to the right joining the axes of the two tensioning rollers.
• the single tensioning wheel is replaced by two rollers integral with a bar giving them a constant gap, this bar being movable in translation following a straight line parallel to the right joining the axes of the two tension rollers.
• FIG. 1 shows a schematic view in side elevation of a group A, in line full and part of a group B associated, in continuous line, of a flexography machine with the device for adjusting the contact pressure according to the invention
• FIG. 2 represents a partial perspective view of an embodiment of the device for adjusting the contact pressure according to the invention mounted on a group such as group A in FIG. 1,
• FIG. 3 represents a simplified view of the kinematics of the device for adjusting the contact pressure
• FIG. 4 shows a simplified view of the kinematics of the contact pressure adjustment device for an alternative embodiment with a pressure roller, eliminating the middle tension roller.
• FIG. 1 two groups 10A and 10B are shown of a flexographic printing machine as well as means 12 for feeding the paper strip 13.
• the machine comprises a solid chassis 14 preventing any deformation, on which the groups A, B and others are mounted.
• Each group includes:
• upstream tensioning roller 32 with an upstream tensioning roller 32, a pressing roller 34, a middle tensioning roller 36 and a downstream tensioning roller 38, defining two portions of strip called upstream strand 40 and downstream strand 42, a first, a second, a third and a fourth point of tangency respectively 44, 46, 48 and 50, disposed respectively between the upstream tension roller and the upstream strand, between the upstream strand and the pressure roller, between the median tension roller and the downstream strand, between the downstream strand and the downstream tension roller, and
• drying means 52 shown in the form of a column type dryer 54 through which the strip of paper 13 passes.
• the plate roller 28 is mounted movable in vertical translation by means of height adjustment 56 which comprise a screw-nut system 58, the translation taking place in the direction of the double arrow 60.
• the support roller support shaft 62 is rotatably mounted and driven by a lateral pinion, not shown for clarity of the drawing, integral with this shaft 62 which meshes with a lateral pinion also not shown, integral with the shaft 64 of the ink roller 20.
• the two ink rollers and plate holder are linked in rotation.
• a common electric motor, with variable speed drive, meshes by its pinion integral with its drive shaft with the lateral pinions of the two ink roller and plate holder so as to be able to adjust the positioning of the rollers and their vi ⁇ rotation tesse, as will be useful for the implementation of the machine, described later ⁇ ment.
• the height adjustment means 56 are integral with a beam 66 movable in translation along the double arrow 68 by means of displacement in translation 70 which also include a screw-nut system 72. This system essentially allows the beam to take two extreme positions front and rear.
• any movement of the beam causes the simultaneous de ⁇ placement of the plate roller 28.
• the tensioning rollers 32 and 38 are mounted in rotation relative to the frame and fixed in translation for a given arrangement of the pressure rollers 34 and middle tensioner 36.
• the pressure rollers 34 and middle tensioner 36 are rotatably mounted and are integral with a carriage 74 movable in translation relative to the beam 66, along the double arrow 75 by means of displacement in translation 76 which comprise a screw system. nut 78.
• group A The implementation of group A is now described in order to show the advantages which the solution according to the present invention provides.
• the strip of paper 13 being in circulation, it passes under the upstream tension roller 32, on the presser water 34, on the middle tension roller 36, through the dryer 54 then under the downstream tension roller 38 before entering group B.
• the paper strip is adjusted in tension, the plate roller 28 carries the sleeve with its plate and it is arranged above the paper strip and above the ink roller 20, the beam being in the front position.
• the contact pressure of the plate roller 18 on the ink roller 20 is adjusted using the translation means 56, more particularly using the screw-nut system 58.
• the paper strip 13 is in the immediate vicinity of the key holder roller. It is then necessary to adjust the key of the paper strip on the printing plate roller, then the initial setting of the strip is adjusted.
• the curve ⁇ is the circle which has for its center the point of tangency 44 which passes through 46A and this circle passes through the point 47A of tangency of the strip of paper with the printing roller, but also by the point 47B of tangency of the paper strip with the plate roller.
• the two points 46 and 48 are arranged outside the perpendicular lines 41, 43 to the right 45 joining the centers of the two tension rollers and passing through the first and fourth points of tangency 44 and 50.
• the decrease in length of the strand 40 is offset by the increase in length of the strand 42.
• this adjustment can be made for one of the groups without adjusting the machine.
• a change of strip or a resumption of service with change of the plate-carrying roller is effected with durations considerably reduced compared to the devices of the prior art.
• Variations in paper quality from the same spool can be taken into account, in particular variations in tension between the lead and the core of the spool.
• the carriage movable in translation and the two rollers is replaced by a single roller 80 mounted for rotation on an arm 82 pivoting around a point 84 disposed on the right joining the axes of the two tension rollers, in the middle.
• the compensation effects are identical.
• Another advantage of the device of the invention flows from its arrangement and appears when one wishes to temporarily interrupt printing or when one is obliged to do so. Indeed, the operator, by maneuvering means for translational movement 70, moves the beam 66 back to the rear position.
• the plate roller 28 always meshes with the pinion of the ink roller thanks to the length of the pinion teeth, because the displacement is very small but sufficient for the plate roller to no longer be in contact with the roller ink, which prevents fouling.
• the plate roller is in contact with the paper strip, which allows the removal of all the ink from the plate roller on this strip, which suffices to allow it to scroll for a few moments.
• screw-nut systems can be replaced by electric jacks with micrometric advance or by any other equivalent means such as hydraulic or pneumatic jacks.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Rotary Presses (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9444972

Family Applications (1)

Country Status (5)

Families Citing this family (4)

Family Cites Families (9)

• 1993
  • 1993-03-09 FR FR9302969A patent/FR2705612A1/fr active Pending
• 1994
  • 1994-03-07 WO PCT/FR1994/000248 patent/WO1994020299A1/fr not_active Application Discontinuation
  • 1994-03-07 AU AU62104/94A patent/AU6210494A/en not_active Abandoned
  • 1994-03-07 EP EP94909157A patent/EP0706456A1/de not_active Withdrawn
  • 1994-03-07 CA CA002164640A patent/CA2164640A1/fr not_active Abandoned

Non-Patent Citations (1)

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