Deflectable hollow socket squeegee for rotary screen printer

Claim 2

In a screen printing machine of the type having a roller squeegee and wherein the pressure exerted by the center region of such roller squeegee upon the printing machine to be forced through the printing screen of the machine tends to be less than the pressure exerted thereupon by the end regions of the roller squeegee, resulting in non-uniform printing by the machine, a combination comprising a printing screen having a surface for supporting a printing medium which is to be forced through said printing screen onto a travelling web to be imprinted; squeegee means for forcing said printing medium through said printing screen, said squeegee means comprising a non-rotatable shaft upwardly spaced from and extending substantially parallel to said surface, a driven tubular jacket rotatably surrounding said shaft; a drive shaft parallel to said non-rotatable shaft; drive gears on said drive shaft for driving said tubular jacket pairs of axially spaced shaft bearings at opposite end portions of said non-rotatable shaft, journalling said drive shaft and maintaining said shafts at a predetermined distance from each other; and means for shifting said squeegee means relative to said surface, including means for displacing said jacket relative to said shaft in direction towards said surface and for deforming said jacket into conformance with the contour of said surface when the surface is downwardly bowed in direction away from said shaft, so that the pressure exerted by said jacket is always uniform over the axial length of said tubular jacket.

Claim 3

In a screen printing machine of the type having a roller squeegee and wherein the pressure exerted by the center region of such roller squeegee upon the printing medium to be forced through the printing screen of the machine tends to be less than the pressure exerted thereupon by the end regions of the roller squeegee, resulting in non-uniform printing by the machine, a combination comprising a printing screen having a surface for supporting a printing medium which is to be forced through said printing screen onto a travelling web to be imprinted; squeegee means for forcing said printing medium through said printing screen, said squeegee means comprising a non-rotatable shaft upwardly spaced from and extending substantially parallel to said surface, a driven tubular jacket rotatably surrounding said shaft and having opposite axial end portions; annuli of teeth on the respective axial end portions; a drive shaft parallel to said non-rotatable shaft; drive gears on said drive shaft and meshing with said annuli of teeth; pairs of axially spaced shaft bearings at opposite end portions of said non-rotatable shaft, journalling said drive shaft and maintaining said shafts at a predetermined distance from each other; and means for shifting said squeegee means relative to said surface, including means for displacing said jacket relative to said shaft in direction towards said surface and for deforming said jacket into conformance with the contour of said surface when the surface is downwardly bowed in direction away from said shaft, so that the pressure exerted by said jacket is always uniform over the axial length of said tubular jacket.

Claim 4

In a screen printing machine of the type having a roller squeegee and wherein the pressure exerted by the center region of such roller squeegee upon the printing medium to be forced through the printing screen of the machine tends to be less than the pressure exerted thereupon by the end regions of the roller squeegee, resulting in non-uniform printing by the machine, a combination comprising a printing screen having a surface for supporting a printing medium which is to be forced through said printing screen onto a travelling web to be imprinted; squeegee means for forcing said printing medium through said printing screen, said squeegee means comprising a non-rotatable shaft upwardly spaced from and extending substantially parallel to said surface, a driven tubular jacket rotatably surrounding said shaft and having opposite axial end portions; annuli of teeth on the respective axial end portions; a drive shaft parallel to said non-rotatable shaft; drive gears on said drive shaft and meshing with said annuli of teeth; pairs of axially spaced shaft bearings at opposite end portions of said non-rotatable shaft, journalling said drive shaft and maintaining said shafts at a predetermined distance from each other; and means for shifting said squeegee means relative to said surface, including means for displacing said jacket relative to said shaft in direction towards said surface and for deforming said jacket into conformance with the contour of said surface when the surface is downwardly bowed in direction away from said shaft, so that the pressure exerted by said jacket is always uniform over the axial length of said tubular jacket.

Claim 5

A combination as defined in claim 2, wherein said annuli of teeth exteriorly surround the respective end portions.

Claim 6

A combination as defined in claim 2, each pair of bearings including an axially outer bearing; and further comprising means at least at one of said axially outer bearings for driving said drive shaft in rotation.

Claim 7

In a screen printing machine of the type having a roller squeegee and wherein the pressure exerted by the center region of such roller squeegee upon the printing medium to be forced through the printing screen of the machine tends to be less than the pressure exerted thereupon by the end regions of the roller squeegee, resulting in non-uniform printing by the machine, a combination comprising a printing screen having a surface for supporting a printing medium which is to be forced through said printing screen onto a travelling web to be imprinted; squeegee means for forcing said printing medium through said printing screen, said squeegee means comprising a non-rotatable shaft upwardly spaced from and extending substantially parallel to said surface, a driven tubular jacket rotatably surrounding said shaft and defining therewith an annular space; and means for shifting said squeegee means relative to said surface, including sealing means sealingly subdividing said annular space into an upper and a lower chamber with reference to the longitudinal axis of said non-rotatable shaft and means for displacing said jacket relative to said shaft in direction towards said surface and for deforming said jacket into conformance with the contour of said surface when the surface is downwardly bowed in direction away from said shaft, so that the pressure exerted by said jacket is always uniform over the axial length of said tubular jacket, said displacing means comprising means for producing a cushion of pressure fluid in said lower chamber acting upon said jacket in direction towards said surface of said screen.

Claim 8

In a screen printing machine of the type having a roller squeegee and wherein the pressure exerted by the center region of such roller squeegee upon the printing medium to be forced through the printing screen of the machine tends to be less than the pressure exerted thereupon by the end regions of the roller squeegee, resulting in non-uniform printing by the machine, a combination comprising a printing screen having a surface for supporting a printing medium which is to be forced through said printing screen onto a travelling web to be imprinted; squeegee means for forcing said printing medium through said printing screen, said squeegee means comprising a non-rotatable shaft upwardly spaced from and extending substantially parallel to said surface, a driven tubular jacket rotatably surrounding said shaft and defining therewith an annular space; and means for shifting said squeegee means relative to said surface, including sealing means sealingly subdividing said annular space into an upper and a lower chamber with reference to the longitudinal axis of said non-rotatable shaft and means for displacing said jacket relative to said shaft in direction towards said surface and for deforming said jacket into conformance with the contour of said surface when the surface is downwardly bowed in direction away from said shaft, so that the pressure exerted by said jacket is always uniform over the axial length of said tubular jacket, said displacing means comprising means for producing a cushion of pressure fluid in said lower chamber acting upon said jacket in direction towards said surface of said screen.

Claim 9

A combination as defined in claim 5; and further comprising vertically extendable and retractable mounting units supporting said non-rotatable shaft.

Claim 10

A combination as defined in claim 6; further comprising adjustable bearings supporting said printing screen at opposite lateral sides of a path in which the web to be printed moves relative to said screen; said mounting units being connected to the respective bearings and said non-rotatable shaft extending through the latter.

Claim 11

A combination as defined in claim 7, wherein said screen is an endless annular screen having respective axial end portions each supported by one of said bearings.

Claim 12

A combination as defined in claim 5, said non-rotatable shaft having an internal passage, and wherein said means for producing comprises a pressure-fluid conduit in said passage and communicating with said lower chamber.

Claim 13

A combination as defined in claim 5; further comprising pressure-fluid supply means communicating with said conduit; and pressure-regulating means interposed in said conduit.