US 4,450,766 AGranted

Unit-to-unit register adjusting apparatus of multicolor printing machine

AssigneeKomori Printing Machinery Co., Ltd.

InventorsTakehiro Inomata, Nobuya Oyabu

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Abstract

Substantially triangular shaped register marks are applied to respective plate cylinders of a multicolor printing machine. Each register mark is made up of a first side extending laterally of axial direction of a plate cylinder and a second inclined side extending downwardly to an end of the first side. Rotation of register marks is detected by a photoelectric detector and a rotary encoder rotating in synchronism with respective plate cylinders generates a reference pulse and a rotation pulse having a shorter period than the reference pulse. Based on the reference pulse, the rotation pulse and an output of the photoelectric detector, a leading edge time difference signal and a trailing edge time difference signal are formed and then integrated by integrators. In response to outputs of the integrators the peripheral direction and the lateral direction of the respective plate cylinders are adjusted. According to this invention in spite of contamination of register marks they can be detected accurately, and irrespective of peculiar rotation of a printing machine stable and accurate adjustment of the register can be made before commencing printing operation.

Claims13

Dependent claims

A unit-to-unit register adjusting apparatus of a multicolor printing machine including a plurality of plate cylinders, said apparatus comprising:

a single substantially triangularly shaped register mark applied to respective plate cylinders, each register mark having a first side extending laterally of axial direction of a plate cylinder and a second inclined side extending downwardly to an end of said first side;
a register mark detector including a projector for projecting light on said register mark and a light receiver for receiving light reflected by said register mark such that said register mark detector generates an output signal including an output pulse corresponding to the alignment of said register mark detector with said register mark as said plate cylinder rotates;
a rotary encoder rotating in synchronism with respective plate cylinders for generating a reference signal having a reference pulse and a rotation signal having a rotation pulse, said rotation pulse having a period shorter than that of said reference pulse;
an input unit comprising gain control means for controlling said output pulse of said register mark detector to have a predetermined peak value, and signal processing means for differentiating an output of said gain control means for producing a differentiated signal having a leading edge pulse and a trailing edge pulse corresponding to leading and trailing edges of the output of said gain control means, respectively;
time difference detecting means responsive to time differences between said leading edge pulse and said rotation pulse and between said trailing edge pulse and said rotation pulse for generating a leading edge time difference signal and a trailing edge time difference signal;
integrating means provided for said time difference detecting means for independently integrating said leading edge time difference signal to generate a leading edge integrated signal and said trailing edge time difference signal to generate edge integrated signal;
first adjusting means responsive to said leading edge integrated signal for adjusting the relative phase angles of respective plate cylinders in the peripheral direction;
and
second adjusting means responsive to said trailing edge integrated signal for adjusting lateral positions of respective plate cylinders.

6 more elements

A method for providing unit-to-unit adjusting of a plate cylinder for a multicolor printing machine including a plurality of plate cylinders, said method comprising the steps of:

disposing a single substantially triangularly shaped register mark on each of said plate cylinder, said register mark having a first side extending laterally of an axial direction of said plate cylinder and a second inclined side extending downwardly to an end of said first side;
projecting a beam of light on said plate cylinder such that said beam of light periodically encounters said register mark and further such that said beam of light is reflected therefrom in a reflected beam of light;
receiving said reflected beam of light and generating in response thereto an output signal including an output pulse corresponding to the detection of said register mark;
generating a reference signal having a reference pulse and a rotation signal having a rotation pulse, said rotation pulse having a period shorter than that of said reference pulse;
limiting said output pulse to a predetermined peak value;
generating a differentiated signal in response to said output signal, said differentiated signal having a leading edge pulse and a trailing edge pulse corresponding to the leading and trailing edges of said output pulse and, accordingly, corresponding to the detection of said first and said second sides of said triangularly shaped register mark;
generating a leading edge differentiated signal in response to the time difference between said leading edge pulse of said differentiated signal and said rotation pulse of said rotation signal;
generating a trailing edge differential signal in response to the time difference between said trailing edge pulse of said trailing edge signal and said rotating pulse of said rotating signal;
generating a leading edge integrated signal corresponding to the integration of said leading edge differentiated signal;
generating a trailing edge integrated signal corresponding to the integration of said trailing edge differentiated signal;
adjusting the relative phase angles of the said plate cylinder in the peripheral direction thereof in response to said leading edge integrated signal;
and
adjusting the lateral position of said plate cylinders in response to said trailing edge integrated signal.

10 more elements

Dependencies are inferred from the claim text.