Abstract:
A cover applier is provided. The cover applier includes a transport system transporting a book, a cover delivery delivering a cover to a book, the cover delivery driven by a servomotor, a book sensor detecting an image printed on the book prior to the cover being delivered to the book and a cover sensor detecting an image printed on the cover prior to the cover being delivered to the book. The servomotor adjusting the position of the cover with respect to the book as a function of the book sensor and cover sensor. A method is also provided.

Description:
Priority is hereby claimed to U.S. Provisional Application No. 61/293,398 filed on Jan. 8, 2010 and hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     The present invention relates generally to post press printing equipment and more particularly to binding books and applying covers to the books. 
     U.S. Pat. No. 7,210,887 purportedly discloses a bookbinding machine for processing inner books which includes a transport system with a multiplicity of inner-book clamps continually movable in a closed continuous track. The bookbinding machine also includes a plurality of workstations driven by a second motor which is independent of the motor that that drives the transport system. 
     U.S. Pat. No. 6,193,458 purportedly discloses a binder/trimmer in which a book block is placed in a carriage, jogged to align the pages and then transported to a milling station in which the spine of the book block is milled to roughen the spine, then to an adhesive application station at which a suitable adhesive is applied to the spine, and thence to a binding station at which the spine of the book is brought into engagement with the center portion of a cover and at which a binding clamp forces the cover against the outer faces of the book block proximate the spine and then to a trimming station. 
     U.S. Pat. No. 5,874,812 purportedly discloses a drive control system for a binding line having first and second separate binding-line segments which includes a first motor driving the first binding line segment and a second motor driving a the second binding-line segment, and a controller coupled to the first and second motors. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a cover applier including a transport system transporting a book, a cover delivery delivering a cover to a book, the cover delivery driven by a servomotor, a book sensor detecting an image printed on the book prior to the cover being delivered to the book and a cover sensor detecting an image printed on the cover prior to the cover being delivered to the book. The servomotor adjusts the position of the cover with respect to the book as a function of the book sensor and cover sensor. 
     The present invention also provides a cover applier including a clamp transport system transporting a book, a cover delivery delivering a cover to a book, the cover delivery driven by a servomotor, a first book sensor detecting an image printed on the book, a second book sensor detecting an edge of the book or the clamp so a distance between the image printed on the book and the book edge or clamp can be determined, a third book sensor detecting the edge of the book or the clamp prior to the cover being delivered to the book and a cover sensor detecting an image printed on the cover prior to the cover being delivered to the book. The servomotor adjusts the position of the cover with respect to the book as a function of the first, second and third book sensors and cover sensor. 
     The present invention further provides a method for applying a cover to a book including the steps of moving a book to a cover delivery device, sensing a printed book image on the book, sensing a printed cover image on a cover, adjusting a position of the cover with respect to the book as function of the sensing of the book and cover and delivering the cover to the book. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the present invention will be elucidated with reference to the drawings, in which: 
         FIGS. 1 and 2  show a cover applier according to the present invention; and 
         FIG. 3  shows another preferred embodiment of a cover applier in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Perfect binders or adhesive binders may use a cover applier to apply a cover to a glued book. The accuracy of the application of the cover critically affects the quality of the finished book. The print to cut register between signatures or books varies from one signature or book to the next, especially on web printed products. Thus, consistently applying the cover to the signature or book itself may still yield unsatisfactory results since the cover applier does not accommodate for variations in the print to cut register. For example, in some cases, a crossover image runs from the inside cover to the first page of the book block. Misalignment in this area may be very noticeable. 
     A servomotor was used previously to drive the cover applier in order to provide consistent cover edge to book registration. However, cover edge to book edge registration does not correct for variations in the print to cut register on the cover or book. 
     The present invention provides a cover applier which corrects for print to cut variations on the cover and/or book by accurately aligning a cover image to a book block image.  FIG. 1  shows a preferred embodiment of a cover applier device  100  in accordance with the present invention including a clamp transport system  20 , a cover delivery  30  and a controller  90 . 
     Clamp transport system  20  includes a plurality of clamps  28  rotating around a clamp orbit path  26 , which may be an endless conveyor and/or a closed continuous loop. Each clamp  28  includes a clamp mainframe  24 , clamp pressure plate  25  and a clamp register pin  23 . Book blocks  22  are aligned in clamp  28  by the register pin  23  and held between pressure plate  25  and mainframe  24 . Book blocks  22  are transported along path  26  to cover delivery  30 . Before reaching cover delivery  30 , book blocks  22  may be transported past a milling station which removes folds in spines  29  of book blocks  22  if desired. After spines are milled, an optional side glue device may be used to apply side glue to the front and back pages of book block  22  adjacent to spine  29  which aides in producing a higher quality book. Glue is applied to spine  29  of each book block  22  via a glue applicator. 
     After glue is applied to spine  29 , book blocks  22  are transported to cover delivery  30 . Cover delivery  30  includes an applier drum  31 , cover transport tapes  39 , cover delivery chains  35 ,  36 , a gearbox  32 , servomotor  33  connected to controller  90  and a phasing device  34 . Cover delivery  30  applies a cover  1  to book block  22  via drum  31  as shown in  FIG. 1 . Cover  1  is subsequently formed around spine  29  of book block  22  in a pressing station downstream. A further conveyor system then transports the book further downstream for trimming and distribution. 
     As shown in more detail in  FIG. 2 , a book block sensor  27  senses a specifically printed target, plurality of targets, or an image printed on book block  22 . The specifically printed target may be, for example, a registration mark or a customized target. If an image is detected, the image may be the actual image printed for the book, for example, an image printed on a first page of book block  22  and for example include text and/or an image related to the contents of the book. Book block sensor  27  may be mounted either on the inside or outside of clamps  28  with respect to clamp conveyor  26  depending upon how book block  22  is laid out or transported in clamp  28 . A second sensor, cover sensor  38 , scans cover  1  at either a specifically printed target, plurality of targets or an image printed on cover  1 . The cover target may be for example, a registration mark or a customized target. If a cover image is detected, the cover image may be the actual image printed on the cover for the book. Book block sensor  27  and cover sensor  38  are connected to controller  90 . For any given job, an offset between sensor  27  and sensor  38  is constant. Controller  90  compares the given offset to the readings of sensors  27  and  38  to determine a correction value if necessary. The correction value is sent to servomotor  33  which compensates accordingly by controlling cover transport tapes  39  via gearbox  32 . 
     Cover  1  is either advanced or retarded in order to compensate for the desired correction and match the image of the cover with the image of the book block. If a specifically printed target or targets are being used the cover targets are matched and/or aligned with the book block targets. A combination of including single or plural images and/or targets may also be used. When cover  1  reaches applier drum  31  the printed cover image (or cover target) will be aligned properly with the printed book image (or book target). An operator will be able to input the appropriate offset, to allow set up of the system on a per job basis. After the initial setup, a constant or variable adjustment may be automatically applied to each cover  1  as it is applied to each book block  22  to align the printed cover image with the printed book image properly. 
       FIG. 2  also shows a phasing device  34 . Phasing device  34  may advance or retard cover transport tapes  39  to allow cover  1  to be deliberately skewed in order to compensate for covers that are not squarely delivered to the transport tapes  39 . Adjustment by phasing device  34  may be made manually or via sensors on the fly. Phasing device  34  may also be connected to controller  90  as desired. 
       FIG. 3  illustrates another preferred embodiment of the present invention. A cover applier  200  including a clamp transport system  220 , cover delivery  230  and controller  290  are shown. Clamp transport system  220 , cover delivery  230  and controller  290  are similar to those shown and described in  FIGS. 1 and 2 . However, clamp transport system  220  includes two additional sensors, sensor  205  and sensor  206  which are also connected to controller  290 . The application of side glue to a first and last page of a book block  222  may make reading a specifically printed target or printed image difficult. Book sensors  205 ,  206  are provided which detect a specifically printed target or targets or a printed image on book block  222  prior to side glue application. Sensors  205 ,  206  are located in a position on path  226  upstream of a side glue applicator. Sensor  205  can then detect a specifically printed target(s) or printed book image while sensor  206  detects an edge of the book block or clamp prior to glue being applied to the first or last page of book block  222 . A location of the specifically printed target(s) or printed book image is then known with respect to clamp  228  or an edge of book block  222 . Side glue can then be applied in a conventional manner. 
     Once cover image  201  or specifically printed target(s) are detected by sensor  238  prior to application of cover  201  to book block  222 , a sensor (similar to sensor  27  shown in  FIGS. 1 and 2 ) detects the book block edge or clamp  228 . Controller  90  compares these values to the values obtained from sensors  205  and  206  to determine the amount of advance or retard required to match the printed cover image with the printed book image as discussed above with respect to  FIGS. 1 and 2 . 
     The embodiment shown in  FIG. 3  may be used with or without a side glue applicator if desired. A phasing device similar to phasing device  34  may also be used with the  FIG. 3  embodiment in order to advance or retard cover transport tapes  339  as desired to compensate for skew for covers that are supplied out of square. 
     In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.