Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F15/00—Screen printers
  • B41F15/08—Machines
  • B41F15/0831—Machines for printing webs
  • B41F15/0836—Machines for printing webs by means of cylindrical screens or screens in the form of endless belts

Definitions

• the invention relates to a rotary screen printing machine for printing web-type or sheet-type material, comprising a main frame on which at least one screen printing unit is mounted, which screen printing unit comprises a stencil, a stencil holder, drive means for rotatable driving of the stencil, a squeegee, a squeegee suspension, a counterpressure roller and a printing paste supply system.
• Rotary screen printing machines of the above- mentioned type are known in practice.
• the known machines are generally provided with several screen printing units mounted on the main frame, the parts of each screen printing unit generally being mounted on or at the main frame.
• the disassembly and assembly of the parts gives rise to problems, particularly in the case of broad machines.
• measures have been taken to facilitate the disassembly and assembly of certain parts, such as the squeegee, but these measures do not give sufficient improvement.
• the object of the invention is to provide a rotary screen printing machine in which the abovementioned disadvantages have been overcome.
• the stencil consists of a cylindrical element with a flat screen fitted around it. Positioning and clamping the flat screen on the cylindrical element is much easier in the case of a slide-out subframe, owing to the easy accessibility.
• the construction according to the invention also makes it possible for a subframe with parts accommodated therein to be replaced in a short time by another subframe, for example when a pattern or colour is being changed. Expedient embodiments of the screen printing machine according to the invention are laid down in the subclaims.
• Fig. 1 shows very diagrammatically the design of a rotary screen printing machine for printing a continuous textile web
• Fig. 2 shows very diagrammatically the design of a rotary screen printing machine for printing a continuous paper web
• Fig. 3 shows very diagrammatically and in per- spective a screen printing unit mounted on the main frame of a rotary screen printing machine according to the invention for printing sheets;
• Fig. 4 shows diagrammatically an end part of a screen printing unit of a rotary screen printing machine according to the invention, in which the parts accommodated in the subframe are omitted;
• Fig. 5 shows a diagrammatic view of the screen printing unit shown in Fig. 4, viewed from the side of the rotary screen printing machine;
• Fig. 6 shows a view in the direction of the arrow VI in Fig. 5, in the working position of the screen printing unit;
• Fig. 7 shows a view such as that of Fig. 6, in which the subframe has been raised
• Fig. 8 shows a view such as that of Fig. 6, in which the subframe is situated next to the rotary screen printing machine;
• Fig. 9 shows diagrammatically a particular embodiment of a stencil of the rotary screen printing machine.
• a rotary screen printing machine which is shown very diagrammatically in Fig. 1, comprises in general a main frame 1 , on which one or more screen printing units 2 are mounted.
• a continuous material web 3 for printing is unwound from a roll 4 and then passed through a web supply station 5 and the screen printing units 2. After printing, the web is passed through a drier 6 and an output station 7, and is then wound onto a roll 8.
• the material web 3 is passed through between a stencil 9 and a rubber blanket 12 which is passed around rolls 10 and 11, the rubber blanket being supported at the position of the stencil 9 by a counterpressure roller 13.
• a rotary screen printing machine of the type shown very diagrammatically in Fig. 1 is intended for printing a continuous textile web. Such a rotary screen printing machine is generally known and requires no further explanation.
• Fig. 2 shows very diagrammatically a rotary screen printing machine for printing a continuous paper web 3.
• this machine corresponds largely to the screen printing machine shown in Fig. 1. Similar parts are therefore indicated by the same reference numbers. The difference lies in the slightly different arrangement of the screen printing units 2 and the absence of a rubber blanket 12.
• Such a rotary screen printing machine is also generally known and requires no further explanation.
• Fig. 3 shows very diagrammatically a screen printing unit 2 of a rotary screen printing machine according to the invention.
• the screen printing unit is mounted on a rotary screen printing machine for printing sheets.
• a sheet for printing is indicated by 3 ' .
• the screen printing unit 2 comprises in general a stencil 9, a stencil holder 14, a squeegee 15 placed inside the stencil 9, a squeegee suspension (not shown), a counter- pressure roller (not shown) and a printing paste supply system 16, consisting of a printing paste tank 17, a paste pump 18 and a printing paste line 19, by means of which line the printing paste is pumped from the tank 17 to the squeegee 15.
• the screen printing unit 2 is mounted on the main frame 1 of the rotary screen printing machine.
• a screen printing unit 2 for a rotary screen printing machine for printing a continuous textile web (Fig. 1) or a continuous paper web (Fig. 2) will be of essentially the same design.
• the stencil 9 can consist of a cylindrical screen with end rings or a cylindrical element with openings around which an originally flat screen has been fitted. At set times it is necessary to remove various parts of a screen printing unit and to refit them. This is the case when cleaning or repair work has to be carried out on the parts, or when a design and/or colour change has to be made, in which case the stencil, the screen and/or the squeegee with printing paste supply system have to be replaced.
• the stencil 9, the stencil holder 14, the squeegee suspension and the printing paste supply system 16 in each screen printing unit are accommodated in a subframe which is movable transversely relative to the main frame 1 of the printing machine.
• Fig. 4 in which an end part of a screen printing unit of a rotary screen printing machine according to the invention is shown diagrammatically, shows the way in which the subframe 21 can be suspended in the main frame.
• the various parts accommodated in the subframe are omitted in Fig. 4.
• Fig. 4 in which an end part of a screen printing unit of a rotary screen printing machine according to the invention is shown diagrammatically, shows the way in which the subframe 21 can be suspended in the main frame.
• the subframe is suspended in guide rails 22 and 23 extending in the transverse direction relative to the main frame 1, as a result of which the subframe 21 is movable transversely relative to the main frame 1.
• the guide rails 22 and 23 are fixed to guide rail supports 24 and 25 which are movable in the vertical direction relative to the main frame 1.
• the guide rail supports 24 and 25 are movable in the vertical direction by means of vertical threaded rods 26 and 27 which are situated at both ends of the guide rail supports 24 and 25 and extend through threaded holes provided in end pieces 28 and 29 of the guide rail supports.
• the rotation of the threaded rods can occur in various ways which are known to a person skilled in the art.
• Dowel pins 31 and 32 on which the subframe 21 rests when the screen printing unit 2 is in the working position, are fitted on the main frame 1 at both ends of the screen printing unit. These dowel pins ensure that when the screen printing unit 2 is in the working position the subframe 21 is positioned accurately in the screen printing unit.
• the dowel pins 31 and 32 are preferably adjustable in height, so that the height of the subframe, and consequently the height of the stencil in the screen printing unit can be adapted to the thickness of the material web to be printed.
• Figs. 5 to 8 show the position of the subframe 21 and the stencil 9 when the screen printing unit 2 is in the working position (Figs. 5 and 6) , in the raised position (Fig. 7) and in the raised and slid-out position (Fig. 8) .
• the various parts are indicated by the same reference numbers as in Fig. 4.
• the subframe is moved upwards so far by means of the four vertical threaded rods 26, 27, 27' (two at each end of the subframe) that the subframe 21 can be slid out of the machine, over the counterpressure roller 13 in the direction of the operating side of the machine (see Fig. 7) .
• the subframe is then slid in the lateral direction out of the machine (see Fig. 8) , during which time the subframe is guided by the guide rails 22, 23, which are in the form of telescopic guide rails.
• work can easily be carried out on the screen printing unit.
• the procedure is reversed for returning the screen printing unit to the working position, in which case the dowel pins 31 and 32 ensure accurate positioning of the subframe in the screen printing unit.
• the construction described above can be used with particular advantage in a sheet rotary screen printing machine in which the stencil consists of a cylindrical element with openings around which an originally flat screen has been fitted.
• Fig . . 9 shows diagrammatically such a stencil 41 with squeegee 42 fitted therein.
• the stencil 41 consists of a cylindrical element 43 with an originally flat screen fitted around it.
• the cylindrical element 43 is provided with register pins 44 in the lengthwise direction, and the screen is provided with register holes which match the register pins 44.
• the screen is provided at the edges with strips made of plastic, such as polyurethane.
• the screen is positioned on the cylindrical element 43 by means of the register pins and the register holes, and is tensioned by means of dividing tension rings 45, 46, which grip behind the strips fitted on the screen and tension the screen in the axial direction.
• the plastic strips also prevent tearing of the screen material during coating, patterning and fitting on the cylindrical element 43.
• the screen material used is preferably material with a high modulus of elasticity, preferably with a nickel electroplated base. Such material is subject to little or no stretching during the tensioning of the screen.
• the screen will in general be rectangular and will be provided on all four sides with plastic strips, in order - as stated above - to prevent tearing of the screen material, while at the side where the register holes are located the strip is also provided with register holes.
• the stencil 41 can be driven by way of the helical toothing 46 disposed thereon.
• the fitting (positioning and clamping) and cleaning of the screen can be carried out easily and quickly in the position of the stencil shown in Fig. 8.
• the drive In this position the drive can remain connected and rotate the cylindrical element slowly during the fitting of the screen, and in this way, as it were, wind the originally flat screen around the cylindrical element.
• the screen printing machine according to the invention can contain several screen printing units which may differ from each other and, in addition, can also have other printing units with other printing formes.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Screen Printers (AREA)
• Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Non-Metallic Protective Coatings For Printed Circuits (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19760990

Family Applications (1)

Country Status (6)

Families Citing this family (9)

Citations (4)

• 1995
  • 1995-05-04 NL NL1000306A patent/NL1000306C2/nl not_active IP Right Cessation
• 1996
  • 1996-04-24 WO PCT/NL1996/000181 patent/WO1996034750A1/en active IP Right Grant
  • 1996-04-24 JP JP53319896A patent/JP3816106B2/ja not_active Expired - Lifetime
  • 1996-04-24 AT AT96911117T patent/ATE188914T1/de not_active IP Right Cessation
  • 1996-04-24 DE DE69606330T patent/DE69606330T2/de not_active Expired - Lifetime
  • 1996-04-24 EP EP96911117A patent/EP0879145B1/en not_active Expired - Lifetime

Patent Citations (4)

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