Printing – Rolling contact machines – Rotary printer and web roll with roller inker
Reexamination Certificate
2000-05-19
2003-04-08
Hirshfeld, Andrew H. (Department: 2854)
Printing
Rolling contact machines
Rotary printer and web roll with roller inker
C101S213000, C101S216000, C101S484000, C101S247000
Reexamination Certificate
active
06543350
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to a method and apparatus for monitoring the contact pressure being exerted when the printed image is being formed in a rotary printing press and more particularly to providing novel means to do so during press operation for any corrective action needed.
The contact pressure being exerted between rotating printing plates during operation of a rotary printing press, such as an offset printing press, a lithograph printing press and the like, is well recognized to undergo significant variation reducing the quality of the printed image. For example, too little contact pressure results in a printed image being faint or missing details and which can require the press operator to adjust the contact pressure during further press operation for avoidance of additional spoilage. Such corrective action taken by the press operator can understandably be carried out long after needed thereby causing considerable loss of the various objects on which the printed image is applied, such as metal cans, plastic containers and the like. In a similar manner, the application of excessive contact pressure when the printed image is being applied causes the liquid link to smear upon deposition and thereby require the press operator to make the necessary adjustments for reducing the amount of this operating factor during continued press operation. Such variation in contact pressure between the printing plates during operation of a rotary printing press can also be caused by a wide variety of operating conditions, including temperature changes, rotational speeds of operation, materials employed to produce the printed image and still other operating factors. A commonly experienced temperature change affecting contact pressure between the rotating printing plates occurs during press start-up after customary periods of press inactivity which causes critical printing surfaces to physical contract due to experiencing lower temperatures while being inactive. It remains desirable, therefore, to provide improved means whereby the printing contact pressure in a rotary printing press can be more effectively monitored during press operation.
Various methods and apparatus are already known to adjust the contact pressure between printing plate members of a rotary printing press. For example, there is disclosed in U.S. Pat. No. 5,181,468 a device to control the operating contact pressure between printing plate rollers of an offset printing press which includes employment of a pneumatic jack device to do so. The press operator is able to vary the operating pressure with such device during press operation. In U.S. Pat. No. 5,622,114 there is disclosed a method for adjusting contact between the printing plate rollers of a rotary printing press which first includes separating the rollers while stationary to permit a piezofilm to be inserted therebetween for generation of an output signal being transmitted to an optical image display device. In a different embodiment, a pneumatic device is employed for adjustment which can further include pressure sensor means connected to said optical display. Both methods are said to be useful “as a partial solution” in enabling automated roller adjustment. An apparatus for such automated roller adjustment in a rotary printing press is also disclosed in U.S. Pat. No. 5,275,099. In doing so, the contact pressure between the rotating plate roller and a form roller physically abutting the rotating plate roller is detected with multiple strain gage sensors mounted on a mechanical pivoting arm. Correcting the contact pressure during press operation to a predetermined value is said to be achieved automatically with a feedback type servomechanism employing comparator means.
To overcome the aforesaid operational difficulties with such type rotary printing press, there is now provided a novel measurement system for monitoring the contact pressure between the printing plate rollers of a rotary printing press while being operated in a further improved manner. In the operation of the present measurement system, a continuous visual display of the dynamic variations occurring in the printing contact pressure during formation of the printed images enables the press operator to make more immediate corrections for any variations displayed beyond the control limits established for an acceptable printed image. In doing so, a display is first recorded on a visual screen, such as a PC monitor or other like device, for both customary upper and lower form roller contact pressure values so recorded when the particular printed image being formed is found acceptable to establish an envelope on the screen during continued press operation with respect to said printed image. A continuing display of said dynamic contact pressure values thereafter immediately notifies the press operator when any manual adjustment of the contact pressure controls is required to maintain said values within the previously recorded envelope appearing on the display screen. Providing a suitable continuous visual display in said manner can be carried out by sensing when a first printing plate disposed on the outer surface of a rotating plate roller of a rotary printing press comes into registration with a second printing plate disposed on the outer surface of a rotating blanket roller in said printing press, concurrently measuring the contact pressure being exerted between the customary pair of rotating form or inking rollers physically abutting the rotating plate roller during the time period when the printing plates on the plate roller and blanket roller remain in registration, further sensing the angular position of the rotating form rollers during the time period when the printing plates on the plate and blanket rollers remain in registration and continuously displaying the variation in contact pressure with respect to angular position of the rotating form rollers. A continuous monitoring of dynamic contact pressure values in this manner can understandably improve the operating efficiency of various type rotary printing presses to include those having single and multiple printing heads as well as those producing single and multicolored printed images.
It is an object of the present invention, therefore, to provide a monitoring system for operation of a rotary printing press to improve the visual quality of the printed image.
It is another object of the present invention to provide said presently improved monitoring system in a manner requiring only a relatively simple modification to the existing rotary printing press apparatus.
A still further object of the present invention is to provide a rotary printing press incorporating the presently improved monitoring system for increased operating efficiency.
It is yet another object of the present invention to provide a novel method for continuously monitoring the resulting quality of a printed image while being formed in a rotary printing press.
These and still further objects of the present invention will become apparent upon considering the following detailed description of the present invention.
SUMMARY OF THE INVENTION
It has now been discovered by the present applicant that a continuous visual monitoring system when carried out in a particularly defined manner can significantly improve the operating efficiency of a rotary printing press. Generally, the presently improved method for monitoring contact pressure between rotating printing plate members in said apparatus requires continuously sensing when a first printing plate disposed on the outer surface of a rotating plate roller in said printing press comes into registration with a second printing plate disposed on the outer surface of a rotating blanket roller in said printing press, concurrently measuring the contact pressure being exerted between a pair of rotating form rollers physically abutting the rotating plate roller during the time period when the printing plates on the plate roller and blanket roller remain in registration, further sensing the angular position of th
Gilliam Ronald D.
Skala Paul C.
Cone Darius N.
Hirshfeld Andrew H.
Intelligent Sensing, Inc.
McDevitt John F.
LandOfFree
Measurement system to monitor printing contact pressure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Measurement system to monitor printing contact pressure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Measurement system to monitor printing contact pressure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3023642