It is a
single operation completed in two stages. Jogging is the method of piling the
sheets into neatly laid edges. It is one of the most important operations in
the printing and binding department. The non-stop feeding of sheets on any
automatic machine mainly depends upon the exactness of jogging and knocking.
A bunch of sheets (say 100 to 200) are
held in between thumb and fore-fingers from the two opposite corners by both
hands, turned upward so that the edges get fanned, pressed and stretched to
allow the air it be filled in between the sheets. The air filling separates
each sheet and facilitates in knocking. The edge of papers towards the binder
is knocked against the table top to align them plane parallel. The same process
is repeated for the second adjacent edge of the papers. In the case of printed
sheets, the papers are knocked at the gripper edge and the side lay so that
these edges are properly aligned. The jogging and knocking of sheets can also
be done with the help of automatic meant for the purpose. A small pile (500-600
sheets) of paper is kept at a time on the slanting tray of the machine. The
pile is allowed to rest against the gripper edge and the side lay and the
machine is switched on. All the sheets in the pile get straightened and aligned
at both edges within a few seconds by the vibrating and knocking action of the
electro-mechanically vibrating tray of the machine. The jogged and knocked
sheets are lifted from the machine and arrange one above the other on a separate
platform. These machines are capable of jogging and knocking about 20000 to
25000 sheets per hour. The following table shows the average speed of jogging
and knocking by hand:-
Sheet
Size Average
Speed per Hour
A0 (841
x 1189mm) 2500
sheets
A1 (594 x 841mm) 3000
sheets
A2 (420 x 594mm) 5000
sheets
A3 (297 x 420mm) 10000
sheets
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