Apparatus and method for regulating ink distribution in a printing machine

An undershot inking unit for a printing machine, said undershot inking unit comprising:

• an ink fountain for supplying printing ink;
• an ink fountain roller communicating with said ink fountain;
• an inking roller;
• a drive for rotating said ink fountain roller, whereby an ink film is generated on the surface of said ink fountain roller;
• an intermittent ductor roller journalled on a pivotal support for periodically engaging said ink fountain roller and an inking roller to transfer said ink film from said ink fountain roller to said inking roller;
• and
• a ductor roller drive for pivoting said support and causing said ductor roller to intermittently engage said ink fountain roller and said inking roller;
• said ductor roller drive including a rotatable control cam, said control cam having a predominant circumferential contour and a subordinate circumferential contour, said subordinate circumferential contour being bounded by a first boundary region and a second boundary region, said predominant circumferential contour being allocated to the throw of said ductor roller on said inking roller, said first boundary region being allocated to the transfer of said ductor roller from said inking roller to said ink fountain roller, said subordinate circumferential contour being allocated to the throw of said ductor roller on said ink fountain roller, said second boundary region being allocated to the transfer of said ductor roller from said ink fountain roller to said inking roller;
• a cam follower connected to said pivotal support for engaging and traversing said control cam to thereby cause said intermittent ductor roller to periodically engage said ink fountain roller and said inking roller;
• a lifter for selectively preventing said cam follower roller to engage and traverse said control cam at said subordinate circumferential contour;
• means for lowering said lifter at a rate independent of the speed of said printing machine to thereby allow said cam follower roller to engage and traverse said subordinate circumferential contour;
• and
• means for raising said lifter at a rate independent of the speed of said printing machine to thereby prevent said cam follower roller from engaging and traversing said subordinate circumferential contour,
• whereby said ductor roller support moves at a rate independent of the rate of the printing speed of said printing machine in moving said ductor roller into and out of engagement with said fountain roller.

A method for regulating the distribution of ink in an undershot inking unit for a printing machine, said undershot inking unit comprising an ink fountain;

• an ink fountain roller cooperating with said ink fountain, for generating an ink film on the surface of said ink fountain roller;
• an inking roller;
• and an intermittent ductor roller journalled on a pivotal support for transferring said ink film to said inking roller as a result of periodic engagement of said ductor roller with said ink fountain roller and said inking roller;
• said method comprising the steps of:
• providing a rotatable control cam, said control cam having a predominant circumferential contour and a subordinate circumferential contour, said subordinate circumferential contour being bounded by a first boundary region and a second boundary region, said predominant circumferential contour being allocated to the throw of said ductor roller on said inking roller, said first boundary region being allocated to the transfer of said ductor roller from said inking roller to said ink fountain roller, said subordinate circumferential contour allocated to the throw of said ductor roller on said ink fountain roller, said second boundary region being allocated to the transfer of said ductor roller from said ink fountain roller to said inking roller;
• providing a cam follower on said pivotal support for traversing said control cam to thereby cause said intermittent ductor roller to periodically engage said ink fountain roller and said inking roller;
• providing a lifter for selectively preventing said cam follower from engaging and traversing said control cam over said subordinate circumferential contour;
• during the rotational cycle of said control cam allocated to the throw of said ductor roller on said inking roller, raising said lifter to thereby prevent said cam follower roller from engaging and traversing said control cam over said subordinate circumferential contour;
• during the rotational cycle of said control cam allocated to the throw of said ductor roller on said ink fountain roller, lowering said lifter at a rate independent of the speed of said printing machine to thereby allow said cam follower roller to engage and traverse said subordinate circumferential contour;
• and;
• subsequently raising said lifter at a rate independent of the speed of said printing machine to thereby prevent said cam follower roller from engaging and traversing said subordinate circumferential contour,
• whereby said ductor roller pivotal support moves at a rate independent of the rate of the printing speed of said printing machine to engage and disengage said ductor roller with said ink fountain roller.

A method for regulating the distribution of ink in an undershot inking unit for a printing machine, said undershot inking unit comprising an ink fountain;

• an ink fountain roller cooperating with said ink fountain, for generating an ink film on the surface of said ink fountain roller;
• an inking roller;
• and an intermittent ductor roller journalled on a pivotal support for transferring said ink film to said inking roller as a result of periodic engagement of said ductor roller with said ink fountain roller and said inking roller;
• said method comprising the steps of:
• providing a rotatable control cam, said control cam having a predominant circumferential contour allocated to the throw of said ductor roller on said inking roller and a subordinate circumferential contour allocated to the throw of said ductor roller on said ink fountain roller,
• providing a cam follower on said pivotal support for engaging and traversing said control cam to thereby cause said intermittent ductor roller to periodically engage said ink fountain roller and said inking roller;
• providing a lifter for selectively preventing said cam follower from engaging and traversing said control cam over said subordinate circumferential contour;
• raising and lowering said lifter relative to said cam follower roller and said pivotal support to control the timing of engagement and traversing of said cam follower with said subordinate circumferential contour so that said pivotal support and the ductor roller supported thereby are periodically moveable at a rate independent of the printing speed of the printing machine.