Inking system with a belt and differential roller speeds

An inking system comprising:

• an ink transfer roller having a first axis about which the ink transfer roller is rotatable, the ink transfer roller having a periphery for receiving ink from an ink supply;
• an ink transfer belt having an ink transfer surface and an opposite drive surface, the ink transfer surface contacts the ink transfer roller at a first nip for transferring ink from the ink transfer roller onto the ink transfer surface;
• a first belt guide roller having a periphery located for engaging the drive surface of the ink transfer belt and for urging the ink transfer surface of the ink transfer belt against the ink transfer roller to define the first nip;
• a second belt guide roller having a periphery located for engaging the drive surface of the ink transfer belt for urging the ink transfer surface of the ink transfer belt against a printing plate for defining a second nip and for transferring ink from ink transfer surface of the ink transfer belt to ink receiving elements on the printing plate;
• the first and the second belt guide rollers having respective axes and being rotatable about their respective axes;
• a rotation drive connected with at least one of the guide rollers for driving the one guide roller connected to the drive to rotate the periphery thereof at a first speed, and the periphery of the one guide roller being in contact with the drive surface of the ink transfer belt for driving the belt to move at the peripheral speed of the one guide roller and for driving the other drive rollers at the same peripheral speed as the drive surface of the belt moving past the guide rollers;
• an ink distribution roller having a peripheral ink distribution surface in contact with the ink transfer surface of the ink transfer belt at a location between the first and second nips on the portion of the surface of the ink transfer belt carrying ink, the ink distribution surface being adapted to rub the ink on the ink transfer surface of the belt as the ink transfer surface of the belt moves past the ink distribution roller;
• the ink distribution roller having a rotation axis about which the ink distribution roller is rotated and having a periphery which rotates in engagement with the ink transfer surface of the ink transfer belt;
• and
• a drive to the ink distribution roller for rotating the ink distribution roller so that the ink distribution surface rotates at a speed different than the speed of the ink transfer surface of the belt as the belt moves past the ink distribution roller, the drive for the ink distribution roller being operable to also cause the vibration and oscillation of the ink distribution roller along the axial direction of the ink distribution roller as the ink distribution roller is rotated.

A method for supplying ink to the printing plate cylinder of an inking system, wherein the inking system comprises:

• an endless loop ink transfer belt having an outer ink transfer surface and an opposite inner drive surface and the printing plate cylinder has ink receiving elements on the surface thereof for receiving ink from the ink transfer surface of the belt, the method comprising:
• rotating the ink transfer belt at a first speed;
• supplying ink to the ink transfer surface of the ink transfer belt at a location along the path of the belt spaced from the ink receiving elements;
• rotating the belt with ink on the ink transfer surface thereof from the location where ink is supplied thereto to the ink receiving elements on the printing plate cylinder and forming a nip at the printing plate cylinder so that ink is transferred from the ink transfer surface of the belt to the ink receiving elements on the printing plate cylinder;
• partially wrapping the ink transfer surface of the belt around the peripheral surface of an ink distribution roller disposed along the path of the belt between the location of ink supply and the nip with the ink transfer elements;
• driving the ink distribution roller to rotate with respect to the ink transfer surface of the belt at a speed different than the speed of the belt for aiding distribution of the ink on the ink transfer surface of the belt;
• and
• simultaneously driving the ink distribution roller to vibrate axially as it rotates, the angle of wrap of the ink transfer surface around the ink distribution roller being large enough that the ink transfer surface experiences several oscillations as the ink distribution roller rubs over the ink transfer surface of the belt.

An inking system comprising:

• an ink transfer roller having a first axis about which the ink transfer roller is rotatable, the ink transfer roller having a periphery for receiving ink from an ink supply;
• an ink transfer belt having an ink transfer surface and an opposite drive surface, the ink transfer surface being in contact with the ink transfer roller at a first nip for transferring ink from the ink transfer roller onto the ink transfer surface;
• a first belt guide roller having a periphery located for engaging the drive surface of the ink transfer belt and for urging the ink transfer surface of the ink transfer belt against the ink transfer roller to define the first nip;
• a second belt guide roller having a periphery located for engaging the drive surface of the ink transfer belt for urging the ink transfer surface of the ink transfer belt against a printing plate for defining a second nip and for transferring ink from the ink transfer surface of the ink transfer belt to ink receiving elements on the printing plate;
• the first and the second guide rollers having respective axes and being rotatable about their respective axes;
• a rotation drive connected with at least one of the guide rollers for driving the one guide roller connected to the drive to rotate the periphery thereof at a first speed, and the periphery of the one guide roller being in contact with the drive surface of the ink transfer belt for driving the belt to move at the peripheral speed of the one guide roller;
• an ink distribution roller having a peripheral ink distribution surface in contact with the ink transfer surface of the ink transfer belt at a location between the first and second nips on the portion of the surface of the ink transfer belt carrying ink, the ink distribution surface being adapted to rub the ink on the ink transfer surface of the belt as the ink transfer surface of the belt moves past the ink distribution roller;
• the ink distribution roller having a rotation axis about which the ink distribution roller is rotated and having a periphery which rotates in engagement with the ink transfer surface of the ink transfer belt;
• and
• a drive to the ink distribution roller for rotating the ink distribution roller so that the ink distribution surface rotates at a speed different than the speed of the ink transfer surface of the belt as the belt moves past the ink distribution roller for aiding in the distribution of the ink on the ink transfer surface of the belt,
• the periphery of at least one of the guide rollers having a drive profile thereon which cooperates with a complementary profile on the drive surface of the ink transfer belt, the drive and complementary profiles being shaped for positive drive of the ink transfer belt longitudinally as the guide rollers rotate, wherein slippage between the ink transfer belt and the printing plate is prevented.

A method for supplying ink to the printing plate cylinder of an inking system, wherein the inking system comprises:

• an endless loop ink transfer belt having an outer ink transfer surface and an opposite inner drive surface and the printing plate cylinder has ink receiving elements on the surface thereof for receiving ink from the ink transfer surface of the belt, the method comprising:
• engaging a drive profile on the peripheral surface of a drive roller with a complementary profile on the drive surface of the ink transfer belt to rotate the ink transfer belt at a first speed;
• supplying ink to the ink transfer surface of the ink transfer belt at a location along the path of the belt spaced from the ink receiving elements;
• rotating the belt with ink on the ink transfer surface thereof from the location where ink is supplied thereto to the ink receiving elements on the printing plate cylinder and forming a nip at the printing plate cylinder so that ink is transferred from the ink transfer surface of the belt to the ink receiving elements on the printing plate cylinder;
• partially wrapping the ink transfer surface of the belt around the peripheral surface of an ink distribution roller disposed along the path of the belt between the location of ink supply and the nip with the ink transfer elements;
• and
• driving the ink distribution roller to rotate with respect to the ink transfer surface of the belt at a speed different than the speed of the belt for aiding distribution of the ink on the ink transfer surface of the belt, the drive and complementary profiles being shaped for positive drive of the ink transfer belt as the drive roller rotates, thereby preventing slippage between the belt and the printing plate.

An inking system comprising:

• an ink transfer roller which receives ink from an ink supply;
• an ink transfer belt having an ink transfer surface in contact with the ink transfer roller at a first nip to receive ink from the ink transfer roller;
• a first guide roller that engages the ink transfer belt and cooperates with the ink transfer roller to define the first nip;
• a second guide roller that engages the ink transfer belt and cooperates with a printing plate to define a second nip at which ink is transferred from the ink transfer belt to ink receiving elements on the printing plate;
• a first drive that rotates at least one of the guide rollers at a first peripheral speed, the engagement of the one guide roller with the ink transfer belt causing the belt to move at the peripheral speed of the one guide roller;
• an ink distribution roller that engages with the ink transfer surface of the ink transfer belt at a location between the first and second nips, the ink distribution surface being adapted to rub the ink on the ink transfer surface of the belt as the ink transfer surface of the belt moves past the ink distribution roller;
• and
• a second drive that rotates the ink distribution roller at a peripheral speed different than the speed of the ink transfer belt to aid in the distribution of the ink on the ink transfer surface of the belt.