Printing – Rolling contact machines
Reexamination Certificate
2000-04-03
2001-09-25
Eickholt, Eugene (Department: 2854)
Printing
Rolling contact machines
C101S228000, C242S421600, C156S504000, C226S030000
Reexamination Certificate
active
06293192
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to newspaper presses for supplying continuous high speed newsprint web to the printing couples of newsprint presses. The printing press art, particularly that for color printing, is adversely affected by the present day tension system employing tension belts that “glaze” the newsprint as by planishing or calendering the newsprint underlying said belts, and thereby “streaking” the newsprint surface, it being a general object of this invention to eliminate streaking and leave the newsprint surface virtually untouched and therefore uniform in texture and surface quality.
Newsprint supplied in roll-form is 40 to 50 inches in diameter, and a full roll is 54 inches wide. In practice, the reel apparatus which supplies the newsprint web to the printing press is adjustable so as to accomodate fractional roll widths, i.e. ¼ to full rolls. Therefore, prior art web tension systems are characterized by four identical tension belts, one for each quarter roll. And, each of these belts inevitably “streaks” the web surface to a noticable degree when applied to tension the web. Also, the presence of these belts reduces access to and the effective pasting area required for splicing new web to expiring web.
Prior art web tensioning control systems adversely calender the newsprint as it is supplied to the roll press. This calendering affects some of the fiber ends of the paper pulp which are sheared off and remain as loose particulate upon the newsprint surface, adhering thereto by static electricity. Therefore, when the newsprint reaches and contacts the impression (or blanket) cylinder for transfer of ink and moisture thereto, the “tack” of the ink causes said particulate to stick onto said blanket cylinder, thereby restricting the moisturized ink from the newsprint; and the moisture (water) grounds the static electricity. Consequently, the longer the roll press runs the greater is the particle paper fiber accumulation; and invariably to a degree readily detected by the naked eye. Because the paper dust particles are wiped onto the newsprint by the aforesaid tensioning belts, said particle accumulation is streaked longitudinally of the newsprint aligned with each of said tensioning belts. Heretofore, this dust particle accumulation has required STOPPING the press in order to wash away said accumulation of particulate, but this is only a temporary solution to the problem which reoccurs. It is an object therefore, to provide a system that virtually eliminates said streaking, eliminting STOPPING the press for blanket cylinder washdown and thereby preserving the surface texture and printing properties of the newsprint so that printing quality is maximized.
State of the art newsprint reels are comprised of three-armed spiders adjustably spaced on a central positioning shaft. There is a chucking spider that engages the core of the newsprint roll onto the spindle of a pastor spider that has a “contact point cover” which indicates the rotative position of the installed roll, whereby a splicing area or zone is established. Said rotative position is indicated by a timing pointer to coincide with a position sensing Hall Effect means that electronically senses said rotational position of the newsprint roll at any press speed or velocity, by which the paster brushes and knives are automatically timed to simultaneously splice a new web to an expiring web.
Tension of the newsprint web as it feeds into the printing press is regulated by a state of the art web force sensing roller, a “dancer roller”, and by a lever system and air pressure regulator for web tensioning control. It is an object of this invention to apply this regulation to spindle braking applied directly to the core of the newsprint roll. In Accordance with this invention, a spindle braking means replaces each tension belt of the prior art systems.
A prerequisite for splicing a new web to a running web is the pre-drive or acceleration of a new roll to the same velocity as the running roll feeding the web into the press. This pre-drive system is state of the art, and is comprised of velocity sensors responsive to the speeds of the pre-drive belt and of the running web feeding the press. When the pre-drive peripheral speed of the new roll is up to the surface speed of the running web, the system is readied for the splice cycle.
It is an object of this invention to provide a newsprint web tension system with improved web-force control applied without adversely affecting other functions and physical properties of the newsprint. Accordingly, existent web force sensing, pre-drive system, and paster-knife system can remain state of the art, this invention being characterized by a multi-force braking mechanism applied to the core spindle of each of the three paster spider arms of the state of the art newsprint reels. In carrying out this invention, said braking mechanisms are comprised of stators attached to existent spider arms, and rotors attached to and driven by modified core supporting spindles, with brake actuating cyliners and controlled air pressure commutation thereto as required.
The prior art “Predrive” systems lack the sensitivity desired in order to avoid over reaction as well as under reaction, which heretofore has required activating a clutch/brake on the new roll accelerator mechanism that functions when the paster-knife mechanism is fired (actuated). This prior art clutch/brake is required because of the “transition period” during which the tension belts are inactive when transfering engagement from the expired newsprint roll to the new newsprint roll in the process of attachment.
The prior art requires a “transition period” control circuit that causes the “Predrive” to be alternately energized and de-energized, and/or re-energized etc., resulting in variable tension and particularly the misregistration of color printing. Consequently, it is not unusual for 350 to 700 full copies of a newspaper to be unacceptable; but these are not always discarded and the paying Advertisers complain about the significant number of poorly printed color adds that are arbitrarily delivered to the readers. Some newspapers throw away about 50 papers before and after a splice, but this is not commonplace. Previous presses ran slower and allowed the pressman to manually intercept the product stream and discard “waste”; but not so with state of the art printing establishments where the pressmen are housed in “quite rooms” and operate the presses remotely. All the good and bad is sold and the Advertisers continue to complain, it being an object of this invention to eliminate poorly printed advertising.
The typical prior art newsprint feed system operates as follows: After the paster-knife mechanism fires and while the Predrive belt is in contact with the new roll, but the new roll not yet in contact with the tension belts, the only means to stop the new roll in an emergency is with the clutch/brake and its control circuit. Accordingly, there is an electrical bypass set at a pre-set resistance in the brake control circuit so as to pass high braking current to the brake for this type of Emergency Stop (E-STOP). This control circuit is set to a fixed voltage value based upon the average mass which is equal to half of the newsprint mass running at a normal press velocity. However, this prior art control circuit does not compensate for smaller or larger width and/or diameter rolls, nor for changes in press velocity. Therefore, the same braking used for a ½ roll is arbitrarily used for a ¼, ¾ and full roll, for an E-STOP during the transition period, which results in abrupt changes in web tension and which often causes the web to break. Since it is common that a press starts with multiple rolls of the same nominal diameter, multiple splices can occur together. And, if any roll splice is “missed” an E-STOP results; several rolls can be in the transition period herein referred to. This occurs more often than one would expect, and usually results in a web break on any roll that is within said
Eickholt Eugene
Maxwell William H.
LandOfFree
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