Printing – Processes – Condition responsive
Reexamination Certificate
2000-01-04
2001-12-18
Yan, Ren (Department: 2854)
Printing
Processes
Condition responsive
C101S148000, C101S247000
Reexamination Certificate
active
06330859
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject invention relates generally to lithographic printing presses and more particularly to an apparatus and method for systematically engaging and disengaging the drive gear of a dampener with the gear train of a printing press and engaging and disengaging the dampener with a plate cylinder in the printing press.
2. Background of the Related Art
On a printing press utilizing the off-set lithographic method of printing there is typically required a dampener for applying dampening solution to a printing plate for ensuring that the non-image area of the plate, and consequently the non-image area of the printed sheet, is kept clear of ink. The dampener requires an actuation mechanism for moving it toward the printing plate to engage the dampener rollers with the plate, thereby enabling the application of dampening solution to the plate, and for moving the dampener away from the printing plate when it is not required for printing. Typically, pneumatic cylinders are employed in the actuation mechanism to engage and disengage the dampener with the printing plate.
An example of a dampener used on a printing press which may utilize an actuation mechanism as described above is that disclosed in U.S. Pat. No. 4,455,938 (the '938 patent) to J. Loudon entitled DAMPENING APPARATUS FOR LITHOGRAPHIC PRESS, the disclosure of which is incorporated by reference. The apparatus described in the '938 patent essentially includes a form roller, a metering roller, and a set of side frames for supporting the rollers. The form roller engages the printing plate for dampening. The rollers are rotated by a gear train of the printing press at a predetermined rotational velocity ratio.
Dampeners may also include a mechanism for engaging and disengaging the printing press gear train from the dampener rollers. This permits the press operator to rotate the printing press cylinders and rollers without rotating the dampener rollers. Among the benefits are reduced component wear and reduced need for maintenance to the dampener. An example of a gear disengaging mechanism for a dampener is disclosed in U.S. Pat. No. 5,551,338 (the '338 patent) to R. Wall et al entitled DRIVE DISENGAGING DEVICE FOR AN OFFSET LITHOGRAPHIC SEAL-TYPE DAMPENING SYSTEM, the disclosure of which is incorporated by reference. A disadvantage of the apparatus described in the '338 patent is it must be manually engaged or disengaged by the press operator, thereby adding additional steps to the printing process. Also, the operator must physically go to each printing head of a multi-head press, as described herein below, to engage or disengage the gear drive before each printing operation. In addition, because the apparatus of the '338 patent does not function in cooperation with existing automated printing functions on the printing press, it is possible, for example, that the operator will engage the dampener while the printing press cylinders and rollers are rotating. Doing so will subject the gear train and dampener to destructive shock loads.
To more fully appreciate the advancement in the art provided by the invention disclosed herein below it is important to note that printing presses very often include several printing heads. A large ‘multi-head’ press can be, for example, well over 30 feet long. Each printing head incorporates the same basic components necessary to print one color of ink, namely, an inking system, a dampener, a blanket cylinder, and a plate cylinder onto which the printing plate is attached. The choice of which printing head(s) to activate for the printing operation is dependent on the number of colors needed and the type of job on the press. It is therefore economical for the operator to have the ability to remotely control the operation of each printing head component such as, for example, the dampener via the dampener actuation mechanism and the gear drive actuation mechanism disclosed and claimed herein below.
SUMMARY OF THE INVENTION
The subject invention is directed to a dampening system for a printing press having a plate cylinder and a gear drive train. A preferred embodiment of the dampening system includes a dampener moveable between a first dampener position, where the dampener is disengaged from the plate cylinder, and a second dampener position, where the dampener is engaged with the plate cylinder.
The dampener includes a first and second side frame. The first side frame is mounted adjacent the gear drive train. A form roller is supported by a shaft that is mounted to the side frames. The roller is rotatable in relation to the side frames. A metering roller is supported by a shaft that is mounted to the side frames. The metering roller is also rotatable in relation to the side frames. The metering roller is in parallel contiguous relation with the form roller.
A drive gear is configured to be drivingly rotated by the gear drive train about a gear shaft, which is defined by either the shaft supporting the form roller or the shaft supporting the metering roller—depending on the dampener configuration. The drive gear is also axially moveable on the gear shaft between a first gear position and a second gear position. A spring is interposed between the drive shaft and the drive gear so to bias the drive gear toward the first gear position. A first coupling portion depends from the drive gear. A second coupling portion depends from the driven roller, defined as the roller corresponding to the gear shaft noted above. The second coupling portion is configured to engage with the first coupling portion when the drive gear is in the second gear position and configured to disengaged from the first coupling portion when the drive gear is in the first gear position. The coupling portions may be formed as engagable raised keys depending from the drive gear and the driven roller.
A first actuator is operatively associated with the first side frame and adapted and configured to translate the drive gear between the first and second gear positions. A second actuator is operatively associated with the printing press and adapted and configured to move the dampener between the first and second dampener positions. A compressed air supply is in fluid communication with and configured to control the first and second actuators.
A preferred embodiment control system for the first and second actuators includes a coupling-engaging valve which provides fluid communication between the compressed air supply and the first actuator for activating the first actuator to move the drive gear between the first and second gear positions. In addition, a dampener-engaging valve provides fluid communication between the compressed air supply and the second actuator for activating the second actuator to move the dampener between the first and second dampener positions. A dampener-on valve is also included providing fluid communication between the compressed air supply and the dampener-engaging valve for switching the dampener-engaging valve to activate the second actuator, thereby moving the dampener from the first dampener position to the second dampener position. And a dampener-selector valve providing fluid communication between the compressed air supply and the coupling-engaging valve and the dampener-engaging valve for switching the coupling-engaging valve to activate the first actuator and for switching the dampener-engaging valve to activate the second actuator.
A dampener-off valve is also included providing fluid communication between the compressed air supply and the dampener-engaging valve for switching the dampener-engaging valve to activate the second actuator to move the dampener from the second dampener position to the first dampener position.
In addition, the control system includes a run-signal valve for preventing the coupling-engaging valve from activating the first actuator to move the drive gear from the first gear position to the second gear position and for preventing the dampener-engaging valve from activating the second actuator to move the d
Crespo Carlito
Hayes Thomas
Jakobsen James W.
Pillsbury & Winthrop LLP
Varn Products Company Inc.
Yan Ren
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