Printing – Multicolor – Rotary machines
Reexamination Certificate
2001-04-24
2003-04-01
Hirshfeld, Andrew H. (Department: 2854)
Printing
Multicolor
Rotary machines
C400S582000, C400S062000, C400S067000, C400S076000
Reexamination Certificate
active
06539860
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a synchronous control system of rotary presses, and more particularly to a synchronous control system of rotary presses comprising a plurality of printing mechanisms driven individually by separate driving means that rotate N turns (N is a natural number) as a plate cylinder rotates one turn, a control section for controlling each driving means, so that printing images are matched with each other and printed on a paper web sequentially passing through each printing mechanism.
BACKGROUND OF THE INVENTION
Synchronous control systems for rotary presses of a type comprising a plurality of printing mechanisms driven individually by separate driving means, a control section for controlling each driving means, so that printing images are matched with each other and printed on a paper web sequentially passing through the printing mechanisms are disclosed in Japanese Published Unexamined Patent Application No. Hei-10(1998)-32992 and Japanese Patent Publication No. 2964238, for example.
The synchronous control system for rotary presses disclosed in Japanese Published Unexamined Patent Application No. Hei-10(1998)-32992 accomplishes synchronous control of rotary presses by monitoring changes in the phase difference between the master shaft mechanical movement and the slave shaft mechanical movement, that is, changes in the distance (phase difference) between the Z-phase signal of a master-side rotary encoder with Z phase connected to a master-shaft driving motor for driving a master-shaft mechanical movement and the Z-phase signal of a slave-side rotary encoder with Z phase connected to a slave-shaft motor for driving a slave-shaft mechanical movement, so that when the phase difference is changed, the slave-shaft driving motors are controlled to correct the change in the phase difference.
The synchronous control system for rotary presses disclosed in Japanese Patent Publication No. 2964238 controls motors for driving driven cylinders by providing phase signal output means to a reference cylinder, and driven cylinders, such as a plate cylinder and a blanket cylinder, each driven by different motors, causing the driving motors for the reference and driven cylinders to operate based on a speed instruction output by a speed command center, outputting a phase-difference signal by processing a signal from the phase signal output means for the reference cylinder and a signal from the phase signal output means for the driven cylinders, both being outputs as the result of the operation of the driving motors, and correcting the speed instruction to the driving motors for the driven cylinders based on the phase-difference signal.
The aforementioned prior-art synchronous control systems have the following problems.
That disclosed in Japanese Published Unexamined Patent Application No. Hei-10(1998)-32992 monitors the phase difference between the driving motors, and corrects the phase difference between the driving motors by regarding the change in the phase difference as the change in the phase difference between the mechanical movements driven by the driving motors. Consequently, it is effective so long as the rotation of driving motors agrees with the rotation of the mechanical movements, that is, the mechanical movements rotate one turn as the driving motors rotate one turn. However, when the rotations of the driving motors and the mechanical movements do not agree with each other, that is, when the mechanical movements rotate only ½ turns or ⅓ turns as the driving motors rotate one turn, the rotational phase of the mechanical movements would remain shifted by ½ or ⅓ turns, the phase shift could not be eliminated unless the entire system is started after the rotational phase of the mechanical movements is corrected to an almost proper phase. For this reason, this synchronous control system has not been put into practical use for rotary presses where the rotation of the mechanical movements is not in a one-for-one relation with that of the driving motors (driving means).
That disclosed in Japanese Patent Publication No. 2964238, on the other hand, obtains a phase difference between both cylinders by processing the phase signal of a reference cylinder and the phase signals of other driven cylinders, and corrects the phase difference by changing the rotational phase of motors for driving the other driven cylinders on the basis of the phase difference. Consequently, the synchronous control system disclosed in Japanese Patent Publication No. 2964238 has no such problems as experienced in that disclosed in Japanese Published Unexamined Patent Application No. Hei-10(1998)-32992. The synchronous control system disclosed in Japanese Patent Publication No. Hei-10(1998)-32992, however, uses transmission mechanisms not only between the reference cylinder and the motor for driving it, but also between the other driven cylinders and the motors for driving them. The “play,” such as backlash, inherent in these transmission mechanisms tends to allow errors to creep into any of the phase signals of the reference cylinder and the other driven cylinders, making the signals unstable and inaccurate. Generating control signals for the driving motors by processing such phase signals may result in unstable control signals, making the control of the driving motors unstable and inaccurate. Thus, it has taken long time before the phase becomes stable at proper levels. For this reason, the conventional controlling method of plate cylinder rotation in rotary presses has often caused defective printing (spoilage) due to phase shifts before the phase becomes stable. From the foregoing, it may be appreciated that a need has arisen for countermeasures to cope with these problems.
SUMMARY OF THE INVENTION
The present invention has been conceived in view of the aforementioned problems. It is an object of the present invention to provide a synchronous control of rotary presses that can be applied to printing mechanisms having plate cylinders rotating 1/N (N being a natural number) turns for one turn of driving means, can control the driving means quite accurately, and can stabilize rotation quickly, accordingly stabilizing the rotation of the plate cylinders and reducing spoilage due to phase shifts.
It is a more specific object of the present invention to provide a synchronous control system for rotary presses where the rotation of plate cylinders is synchronized by using a plate cylinder signal generated for one turn of the plate cylinders, a first pulse signal output in proportion to the amount of angular displacement along with the rotation of the driving means, and a second pulse signal output for one turn of the driving means, setting in advance a driving reference comprising a reference speed and a reference phase, replacing the rotational phase of the plate cylinders for matching printing images with a predetermined reference with a rotational phase of the driving means corresponding to the aforementioned rotational phase, converting a shift between the driving means rotational phase for matching printing images with a predetermined reference and the driving means rotational phase in the normal state into the number of outputs of the first pulse signals, which is set as a correction value, producing a virtual feedback phase by shifting the driving means rotational phase by the amount of the correction value, and controlling so as to synchronize the driving reference phase with the virtual feedback phase of each driving means.
It is another object of the present invention to provide a synchronous control system for rotary presses where a plate cylinder signal output for one turn of the plate cylinders, a first pulse signal generated in proportion to the amount of angular displacement in accordance with the rotation of the driving means, a second pulse signal output for one turn of the driving means, and a driving reference comprising a driving reference speed and a driving reference phase based on a third pulse signal and a fourth pu
Kawamori Hideo
Tsunashima Makoto
Cone Darius N.
Hirshfeld Andrew H.
McGlew and Tuttle , P.C.
Tokyo Kikai Seisakusho Ltd.
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