Patent Publication Number: US-7216585-B2

Title: Shaftless motor drive for a printing press with an anilox inker

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to printing presses and more particularly to a device and method for driving rolls and cylinders in a printing press. 
     2. Background Information 
     Offset lithographic printing presses typically have a plate cylinder carrying an imaged plate. During printing, the plate is inked, and the inked image is transferred to a blanket which then contacts paper sheets or a continuous web of paper. Ink for the plate cylinder may be provided via an anilox inker, which has an anilox roller having a series of cells for providing ink via a roller to a plate cylinder. 
     The drive for an offset lithographic printing press traditionally has included a common drive shaft running on a gear side of the printing press, with worm gears and other gears deriving power from the shaft. 
     Other shaftless drive configurations for lithographic offset printing presses use direct or indirect drive motors, which supply the necessary driving forces to the plate and/or blanket cylinders using one to four motors. A separate or additional motor typically is used to drive the ink fountain. 
     Commonly-owned U.S. Pat. No. 6,050,185, issued Apr. 18, 2000, purports to disclose a shaftless drive with a first drive motor driving a first inker roller either directly or via a further drive. The first drive motor is mechanically coupled to the first plate cylinder via a first gear train, which may include a gear wheel mounted to the drive shaft of the first plate cylinder. A second drive motor drives another plate cylinder and inker roller. The first blanket cylinder and the second blanket cylinder of the press are mechanically coupled to one another and are driven by a third drive motor. 
     The &#39;185 patent does not disclose an anilox inker, nor does it disclose a two-motor configuration, an inking form roll or an inking roll with a similar diameter to the plate cylinder. 
     European Patent Application No. 0 699 524 purports to disclose an offset printing machine. Cylinder and functional groups are driven with minimum technical requirements. A printing unit is provided where the plate cylinders are each driven by a separate electric motor and are not mechanically coupled to each other. Independently driven cylinders in a folder are also disclosed. 
     International Patent Application No. 95/24314 and related U.S. Pat. No. 5,782,182 purport to disclose a printing group for a color-printing web-fed rotary press arranged in a bridge design. The bridge units may be symmetrically distributed in the vertical direction and horizontally movable, to achieve a low height. Each unit side has a plate cylinder and a blanket cylinder. An inking unit for the plate cylinder may include, in place of an inking trough and an inking roller, a chamber doctor blade in connection with an anilox roll. The drive of the dampening unit and of the inking unit can function through friction with the plate cylinder, or by means of an individual motor drive of the inking roller and of the dampening agent application roller, or by means of know gear wheel drives. No driving of the plate cylinder through a motor directly driving the inking unit is disclosed. Moreover, when a drive motor is directly connected to the plate cylinder, proper lateral registration is complicated. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a printing unit of an offset printing press comprising: 
     a first plate cylinder; 
     a first blanket cylinder for selectively contacting the first plate cylinder; 
     an anilox inker for inking the first plate cylinder; 
     a first motor directly connected to the anilox inker for driving the anilox inker and connected to the first plate cylinder for driving the first plate cylinder; 
     a second plate cylinder; 
     a second blanket cylinder for selectively contacting the second plate cylinder; 
     a second anilox inker for inking the second plate cylinder; and 
     a second motor directly connected to the second anilox inker for driving the second anilox inker and connected to the second plate cylinder for driving the second plate cylinder. 
     The anilox inkers preferably include an ink form roll and an anilox roll with an ink chamber, the motors directly driving the respective ink form rolls. 
     The ink form roll preferably has the same diameter as the plate cylinders, thereby improving drive characteristics. The anilox roll may be smaller than or similar to the plate cylinder diameter. 
     In a first embodiment, the printing press includes a third motor for driving the first and second blanket cylinders. In this embodiment, the first motor drives the first form roll directly, and the anilox roll and the first plate cylinder through a set of gears, and the second motor drives the second form roll directly and the second anilox roll and the second plate cylinder through a second set of gears. 
     The blanket cylinders are driven by the third motor through a third set of gears, which may include the blanket cylinder being directly geared with two gears together, the motor driving one of the gears. Alternately, each blanket cylinders may have a separate gear separate from the other, with each gear being driven by the third motor. 
     The plate cylinders can be separated from the blanket cylinders during throwoff since the three sets of gears are separate, and each plate cylinder/blanket cylinder combination can remain printing while the other plate cylinder is thrown off. 
     In a second embodiment, the first and second motors also drive the blanket cylinders. The anilox inkers are driven directly, and a first gear connected to the motor drives the first plate cylinder and a second gear connected to the second motor drives the second plate cylinder. The first and second blankets are connected to a third and fourth gear, respectively. When both print couples are printing, one of the first and second gears drives the third and fourth gears, so that all cylinders are driven. 
     To permit throwoff of the first plate cylinder, the first gear and the third gear can be disengaged, while the second gear drives the third and fourth gears. The second plate cylinder can remain in a printing mode. To permit throwoff of the second plate cylinder, the second and fourth gears can be disengaged. The first plate cylinder then still can print. 
     Preferably, the first and second gears are axially movable with respect to their respective plate cylinders, so as to permit the disengagement from the third and fourth gears, respectively. 
     The present invention also provides a method for driving a printing unit having a first anilox inker, a first plate cylinder, a first blanket cylinder selectively contacting the first plate cylinder, a second blanket cylinder, a second plate cylinder selectively contacting the second plate cylinder, and a second anilox inker, the method comprising the steps of: 
     directly driving the first anilox inker using a first motor; 
     indirectly driving the first plate cylinder using the first motor; 
     directly driving the second anilox inker using a second motor; and 
     indirectly driving the second plate cylinder using the second plate cylinder. 
     The method may further include driving the first and second blanket cylinders with one of the first and second motors, or with a third motor. 
     When contact is removed between the first plate cylinder and first blanket cylinder, the second plate cylinder, second anilox inker and first and second blanket cylinders are capable of continued operation. When contact is removed between the second blanket cylinder and the second plate cylinder, the first anilox inker and first and second blanket cylinders are capable of continued operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the present invention are described below by reference to the following drawings, in which: 
         FIG. 1  shows a side view of a first embodiment of a double print unit of a printing press according to the present invention; 
         FIG. 2  shows a side view of a second embodiment of a double print unit of a printing press according to the present invention; 
         FIG. 3  shows a partial view of one print unit of the configuration of the embodiment of  FIG. 1 ; 
         FIG. 4  shows a partial view of one print unit of another configuration of the embodiment of  FIG. 1 ; 
         FIG. 5  shows a partial view of one print unit of the embodiment of  FIG. 2  with both print couples printing; 
         FIG. 6  shows a partial view of one print unit of the embodiment of  FIG. 2  with the right print couple printing; and 
         FIG. 7  shows a partial view of one print unit of the embodiment of  FIG. 2  with the left print couple printing. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a gear side of one embodiment of a printing press  1  having two shaftless printing units  3  and  4 . A web  5  is printable on both sides by the lithographic offset printing units  3 ,  4 . Printing unit  4  includes a first print couple having a plate cylinder  16  and a blanket cylinder  18 . An anilox roll  12  with an ink chamber  13  and an ink form roll  14 , which together define an anilox inker, provide ink to the plate cylinder  16 . Print unit  4  has a second printing couple having a plate cylinder  36  and a blanket cylinder  38 . The blanket cylinders  18  and  38  function as impression cylinders for each other, and are in contact with the web when either or both of the print couples is printing. 
     In press  1 , the anilox inker for plate cylinder  16  is driven at the ink form roll  14  by a motor  20 , which drives an axle of the roll  14 . As shown in  FIG. 3 , a gear  40  on the axle of the cylinder  14  connects with a gear  42  on an axle of the anilox roll  12  and with a gear  46  on an axle of the plate cylinder  16 . Motor  20  thus drives rolls  12 ,  14  and cylinder  16 . Ink form roll  14  and plate cylinder  16  preferably are of the same diameter. The anilox inker has the advantage that pre-inking of plate cylinder  16  can occur prior to moving the plate cylinder  16  back into contact with blanket cylinder  18  after throwoff. No ink keys need to be adjusted with the anilox inker, and the proper ink coverage can be provided on the web  5  with the first rotation of the blanket cylinder  18 . 
     Blanket cylinders  18  and  38  are driven by a motor  21  which is connected to a gear  50 . Gear  50  drives a gear  51  in one side, which then drives a gear  53  on a shaft of blanket cylinder  18 . Gear  50  drives another gear  52  on the shaft of blanket cylinder  38 . Gears  52  and  53  are not in contact. 
     Another motor  22  drives the axle of ink form roller  34 , on which axle is a gear  60  driving gears  62  and  66 . Gears  62  and  66  drive the plate cylinder  36  and the anilox roll  32 , respectively. 
     Plate cylinders  16  and  36  can pivot away from blanket cylinders  18 ,  38 , respectively, during a throwoff operation. Since motors  20 ,  21 ,  22  are independent, print couple  16 ,  18  and blanket cylinder  38  can be run when plate cylinder  36  is thrown off, and print couple  36 ,  38  and blanket cylinder  18  can be run when plate cylinder  36  is thrown off. Thus printing can continue with one print color while the other plate cylinder is, for example, provided with a new image. 
       FIG. 4  shows an alternate configuration of  FIG. 3  where the motor  21  drives gear  50 , which drives gear  52  as in  FIG. 3 . However, gear  52  then drives gear  53  to drive blanket cylinder  18 . While the  FIG. 4  configuration requires fewer gears, the power distribution in the  FIG. 3  configuration may be more desirable. 
       FIG. 2  shows an alternate two-motor embodiment of a printing press  101  according to the present invention. While the three-motor configuration of  FIG. 1  provides more balanced loads, the two-motor configuration reduces the number of motors required. Printing unit  104  of printing press  101  includes a first print couple having a plate cylinder  116  and a blanket cylinder  118 . An anilox roll  112  with an ink chamber  113  and an ink form roll  114 , which together define an anilox inker, provide ink to the plate cylinder  116 . Print unit  104  has a second printing couple having a plate cylinder  136  and a blanket cylinder  138 . The blanket cylinders  118  and  138  function as impression cylinders for each other, and are in contact with the web when either or both of the print couples is printing. 
     In press  101 , the anilox inker for plate cylinder  116  is driven at the ink form roll  114  by a motor  120 , which drives an axle of the roll  114 . 
     As shown in  FIG. 5 , a gear  140  on the axle of ink form roll  114  connects with a gear  142  on an axle of the anilox roll  112  and with a gear  146  on an axle of the plate cylinder  116 . Motor  120  thus drives rolls  112 ,  114  and cylinder  116 . The ink form roll  114  and the plate cylinder  116  preferably are of the same diameter, so as to provide better force and ink distribution. Gear  146  also is movable axially with respect to cylinder  116 , so as to be selectively engageable with a gear  148  connected to blanket cylinder  118 . Gear  148  is geared to gear  168  of blanket cylinder  138 . 
     Another motor  122  drives the axle of ink form roller  134 , on which axle is a gear  160  driving gears  162  and  166 . Gears  162  and  166  drive the plate cylinder  36  and the anilox roll  132 , respectively. Gear  166  is selectively engageable with gear  168 , but in  FIG. 5 , gear  168  is not in contact with gear  166 . So, gear  166  is driven by motor  122  and gear  168  by motor  120 . 
       FIG. 6  shows plate cylinder  136  thrown off of blanket cylinder  138  and gear  166  disengaged from gear  168 . Motor  120  drives rolls  112  and  114  and cylinders  116 ,  118  and  138 . 
       FIG. 7  shows plate cylinder  116  thrown off blanket cylinder  118 , with gears  146  and  148  disengaged. Motor  122  drives rolls  132  and  134  and cylinders  136 ,  138  and  118 . 
     In addition to the plate cylinder-blanket cylinder throwoff, the ink form roll also may be thrown off its respective plate cylinder or off its respective anilox roll. “Plate cylinder” as defined herein may include any image-carrying cylinder.