Abstract:
A register device for insertion into a channel of a printing unit cylinder. The device includes a rod defining an axial direction and a pin support movable in the axial direction by the rod, the rod being movable with respect to the pin support in a direction perpendicular to the axial direction. A register pin is attached to the pin support. Also provided is a register device with a pin support, a register pin and shims for altering the position of the register pin on the pin support.

Description:
BACKGROUND INFORMATION 
     The present invention is directed generally to printing presses and more particularly to a plate cylinder of a printing press, to a register pin adjustment device and to a method for adjusting a register pin. 
     U.S. Pat. No. 6,382,103 discloses a lateral registration device for printing plates in a plate cylinder, using axially shiftable insertion strips. The strips have register pins which engage recesses in beveled end of the flexible printing plates. Each register pin is fixedly connected to an insertion strip or made of one piece with it. 
     U.S. Pat. No. 5,419,248 discloses a device for aligning printing plates on a plate cylinder. A plurality of adjustment elements spaced apart from one another are located in a bore. The adjustable elements have moveable register pins thereon. Each adjustment element is fixed to the bore by turning a spreading screw, which spread wings of the adjustment element to wedge the adjustment element in the bore to provide a course adjustment. For fine adjustment, a threaded screw is rotated to move the register pin relative to the adjustment element. An actuating rod for tensioning elements does not move the adjustable elements. 
     U.S. Pat. Nos. 4,748,911 and 5,379,694 disclose other later register adjustment devices. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to reduce the manufacturing tolerances necessary for a register device. An alternate or additional object of the present invention is to provide a register device which is easy to install. 
     The present invention provides a register device for insertion into a channel of a printing unit cylinder. The device includes a rod defining an axial direction and a pin support movable in the axial direction by the rod, the rod being movable with respect to the pin support in a direction perpendicular to the axial direction. A register pin is attached to the pin support. 
     The pin support generally slides in axially in the channel with little or no clearance. By permitting the rod to move in the axial direction with respect to the pin support, the register device is easy to install and manufacturing tolerances, including those for the channel, may be reduced. 
     The rod may be movable in the axial direction with respect to the pin support, for example, by providing a hole in the pin support, with the pin support receiving the rod with a clearance in the hole. 
     The rod provides for fine adjustment of the register pin in the axial direction. 
     It may also be desirable to provide a coarse adjustment, for example for different web widths. The pin support thus may be adjustable with respect to the rod when removed from the machine, for example by placing holding bolts in different axial locations along the rod. Alternately, rods of different length could be used to provide this course adjustment. 
     The register device may include a second rod, a second pin support and a second register pin, or as many register pins as necessary. 
     When the register device is installed, the rod may move the register pins axially, and the pin support is generally axially fixed with respect to the rod. However, to aid in permitting the movement of the pin support in the direction perpendicular to the axial direction, and the pin support may be attached to the rod so that the pin support can move in the axial direction with respect to the rod by a movement amount, the movement amount being less than 0.1 millimeters. This amount generally will not adversely affect print quality, depending on the type of print job. 
     The present invention also provides a register device for insertion into a channel of a printing unit cylinder having a rod defining an axial direction, a pin support movable in the axial direction by the rod, a shim replaceably connected to the pin support, and a register pin supported on the shim. 
     By having a replaceable shim, the thickness of the shim can be adjusted so that the register pin is located at the proper distance from the pin support. This permits the register pin to fit into the slot in the plate cylinder so that the register pin and the pin support slide axially with ease through the channel. Ease of installation can be increased, as can manufacturing tolerances. 
     The present invention also provides a plate cylinder having a channel for receiving the register devices, as well as a method for adjusting the axial registration of a printing plate using the devices. 
     The present invention also provides a method for installing a register device in a channel and a slot of a printing unit cylinder comprising the steps of: placing a pin support having a register pin in the channel so that the register pin extends into the slot; determining if the pin support and the register pin slide axially in the channel; and if the pin support and register pin do not slide axially in the channel, placing a shim between the register pin and the pin support. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be described with respect to a preferred embodiment in which: 
     FIG. 1 shows a register device of the present invention with two register pins; 
     FIG. 2 shows a side view of a plate cylinder according to the present invention with the register device of FIG. 1 installed; 
     FIG. 3 shows a side view of one of the pin supports of the FIG. 1 device; 
     FIG. 4A shows a lateral view of one of the pin supports of the FIG. 1 device; 
     FIG. 4B shows more detail from section S of FIG. 4B; and 
     FIG. 5 shows an end view of the FIG. 1 device. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a register device  10  according to the present invention for two register pins  12  and  22 . Register pins  12  and  22  each provide axial, also known as lateral, registration for a printing plate on a plate cylinder. Register pin  12  is fixed prior to installation of device  10  via a connector  15  to a register pin support  14 , and register pin  22  is fixed to a register pin support  24  by a connector  25 . Register pin supports  14 ,  24  may be made of metal, for example stainless steel, and may be cylindrical to fit slidingly in a channel of a plate cylinder with little or no clearance in the channel. 
     A rod  16  has an axis A-A defining an axial direction. Rod  16  may pass through an eccentric hole in register pin support  14 . The hole has an inside circumference with a diameter larger than the diameter of the outer circumference of the rod  16 , so that register pin support  14  can move in a direction perpendicular to the axial direction. Prior to installation of device  10  in a plate cylinder, the axial location of pin support  14  on rod  16  can be set via nuts  60 ,  62 , which are threadedly attached to rod  16 . A lock nut  64  can be provided for one or both nuts  60 ,  62 . Due to the clearance between the hole in the pin support  14  and the rod  16 , the rods  16  can float in the direction perpendicular to the axial direction with respect to the pin support  14 . The device  10  thus can be installed with ease even if the channel is not perfectly bored. 
     When the device  10  is installed, register pin  12 , pin support  14  and rod  16  can move axially together. To adjust the axial location of pin  12 , an external plate register tool such as that disclosed in U.S. Pat. No. 6,443,065, the entire disclosure of which is hereby incorporated by reference herein, may be used. A fixing device  36  of a locking end cap  32  then may fix the axial location of rod  16  and thus set the axial registration for register pin  12 . Other devices for moving pin  12  and/or rod  16  however may be used. 
     If a more course adjustment for the register location of pin  12  is desired, for example for a different printing plate width or web width, a different length rod  16  may be used, or if rod  16  is properly sized and so threaded, nuts  60 ,  62  may be moved to a new location on rod  16 . 
     A second rod  26  is used for adjustment of register pin  22  and pin support  24 . As shown, rod  26  need not extend fully through the pin support  24 . Rod  16  passes with a clearance through pin support  24 . The axial position of pin  22  may be fixed by a second fixing device  34 . 
     A support slide  30  may be provided to and fixed to rod  16  to provide extra support for rod  16 . 
     FIG. 2 shows the register device  10  installed in a channel  44  of plate cylinder  40 . Pin support  14  fits in channel  44  so that pin support  14  can slide, but have little or no movement in a direction perpendicular to the axial direction. A slot  42  of the plate cylinder  40  extends between an outer surface  46  on which a printing plate is supported, and channel  44 . Register pin  12  extends from the channel  44  into the slot  42 . Register pin  12  thus can set the register for a printing plate, which has a notch as described in U.S. Pat. No. 6,439,117, the entire disclosure of which is hereby incorporated by reference herein. 
     Access holes  84 ,  86  may be provided at an end of the cylinder  40  to provide access to fixing devices  36 ,  34 . 
     FIG. 3 shows a side view of pin support  14  of the FIG. 1 device. Register pin  12  is fastened via a connector  15 , for example an Allen-head screw, to pin support  14 . Connector  15  enters a hole  72  perpendicular to a planar surface  70  of pin support  14 . If during installation, an operator determines that register pin  12  is not fitting well into the slot  42  (FIG.  2 ), for example, the register pin  12  is bending and creating friction which impedes axial sliding of pin support  14 , the operator may remove the pin support  14  and provide a shim  13  between planar surface  70  and register pin  12 . Shims  13  may be made of plastic, and may be provided in varying thicknesses T, for example 0.025 mm, 0.127 mm, 0.25 mm and 0.5 mm. The operator thus can select the thickness T which permits register pin  12  to slide well in slot  42 . Planar surface  70  thus can be manufactured so as to be below slot  42  when co-planar with slot  42 , but need not be manufactured to perfect precision as the shims can compensate for deviance. 
     FIG. 4A shows a lateral view of pin support  16  of the FIG. 1 device. As shown, pin support  14  has a hole  54 , whose inner circumference has a greater diameter than the outer diameter of the outer circumference of rod  16 . Thus a clearance D 1  results between the rod  16  and the pin support  14 , which during installation of device  10  provides for movement of rod  16  in a direction perpendicular to the axial direction. In order to permit this movement with the embodiment shown, nuts  60 ,  62  may be spaced so that a slight clearance D 2 , as shown in FIG. 4B, is provided in the axial direction. Nut  62  is in direct contact with pin support  14  in this view, so the entire clearance D 2  is between nut  60  and pin support  14 . This clearance D 2  however is small enough so as not to alter print quality or lateral registration, and is for example preferably 0.1 mm or less, depending on the type of print job. Thus, while pin  12 , support  14  and rod  16  generally move axially together to set the register, there can be a slight axial movement which does not affect print quality. 
     It should be noted that while the preferred embodiment is shown with clearances D 1 , D 2  permitting movement of rod  16  with respect to the pin support  14  in the direction perpendicular to the axial direction, other devices or configurations attaching pin support  14  to rod  16  may be provided to permit rod  16  to move perpendicularly with respect to pin support  14 . 
     It should also be noted that pin support  24  may also float with respect to rods  16  and  26 , in a similar manner. 
     FIG. 5 shows an end view of the FIG. 1 device. Once device  10  is installed in channel  44  (FIG.  2 ), it may be fastened by bolts  80 ,  82  of end cap  32  to the plate cylinder. Access holes  84 ,  86  in cylinder  40  (FIG. 2) permit the operator to loosen and fasten fixing devices  36 ,  34 , which fix rods  16  and  26 , respectively. Fixing devices  36 ,  34  may for example be set screws which act directly on the ends of rods  16 ,  26 . 
     While a two register pin device  10  has been shown, a device  10  with any number pins is possible.