Processing

Please wait...

Settings

Settings

Goto Application

1. WO1997046386 - SCREEN PRINTING PRESS HAVING LONGITUDINAL, LATERAL AND ANGULAR SCREEN FRAME REGISTRATION SYSTEM AND METHOD

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

What is Claimed Is

1 In a screen printing press for a web having defined, successive areas and indicia provided in predetermined positions relative to each of the defined areas, the press including a base defining a work station, a screen supported on the base for movement between a printing position overlying the work station and an interrupted position spaced from the work station, and a feeding means for advancing the web along a path of travel to successively feed the defined areas of the web toward the work station, a registration system for successively positioning the defined areas of the web in a desired predetermined relationship to the screen as successive defined areas are brought into a position to be printed, the registration system comprising
a longitudinal shifting means for adjusting the longitudinal alignment between the screen and the web along the path of travel of the web,
a lateral shifting means for adjusting the lateral alignment between the screen and the web in a direction transverse to the path of travel of the web,
an angular shifting means for adjusting the angular alignment between the screen and the web about a reference axis perpendicular to a plane containing the web, a sensing means for sensing the correct positions and orientation of the indicia that are occupied when the defined areas of the web are in the predetermined relationship relative to the screen, and
a control means responsive to the sensing means for controlling the longitudinal, lateral and angular shifting means to adjust the alignment between the screen and the web until the correct positions and orientation of the indicia are sensed

2 A registration system as recited in claim 1 , wherein the feeding means is the longitudinal shifting means 3 A registration system as recited in claim 1 , further comprising a pair of longitudinally spaced, laterally extending support bars on which the screen is supported for movement, each support bar being supported on the base for axial shifting movement in a direction transverse to the path of travel of the web, the lateral and angular shifting means including a pair of motors supported on the base, each motor having an axially shiftable output shaft connected to one of the support bars for shifting the support bar when the motor is energized such that lateral alignment between the screen and web is achieved by energization of both motors to shift the support bars relative to the base without shifting the bars relative to one another, and angular alignment is achieved by energization of the motors to shift the support bars relative to one another

4 A registration system as recited in claim 1 , wherein the sensing means includes a pair of sensing elements movable with the screen

5 A registration system as recited in claim 3, wherein the sensing means includes a pair of sensing elements suspended from the support bars so that the sensing elements are moved with the support bars upon actuation of the lateral and angular shifting means

6 A registration system as recited in claim 5, wherein the sensing elements are supported for movement between an extended sensing position and a retracted storage position, the registration system further including an actuator for moving the sensing elements between the sensing and storage positions

7 A registration system as recited in claim 6, wherein the sensors, in the sensing position, extend over the work station between the web and the screen

8 A registration system as recited in claim 7, wherein each sensing element includes at least one fiber optic bundle directed toward the web when the sensing element is in the sensing position 9 A registration system as recited in claim 3, further comprising a frame unit on which the screen is supported, wherein the support bars each include a pair of spaced vertical pins and the frame unit includes structure defining a circular hole and three slots, each aligned with one of the pins of the support bars so that the frame is supported for movement with the support bars, the circular hole defining a vertical axis about which the frame unit is pivoted upon actuation of the angular shifting means to adjust the angular alignment between the screen and the web The frame unit defines a single pivot point about which the frame can be pivoted to adjust the theta position of the frame The pivot axis is adjustable in the Y axis to facilitate Y-axis adjustment of the frame

10 In a screen printing press for a web having defined, successive areas and indicia provided in predetermined positions relative to each of the defined areas, the press including a base defining a work station, a screen supported on the base for movement between a printing position overlying the work station and an interrupted position spaced from the work station, and a feeding means for advancing the web along a path of travel to successively feed the defined areas of the web a predetermined distance toward the work station, a registration system for successively positioning the defined areas of the web in a desired predetermined relationship to the screen as successive defined areas are brought into a position to be printed, the registration system comprising
a longitudinal shifting means for adjusting the longitudinal alignment between the screen and the web along the path of travel of the web,
a lateral shifting means for adjusting the lateral alignment between the screen and the web in a direction transverse to the path of travel of the web,
an angular shifting means for adjusting the angular alignment between the screen and the web about a reference axis perpendicular to a plane containing the web, at least one camera for receiving images from the desired locations that are occupied by the indicia when the defined areas of the web are in the predetermined relationship relative to the screen,
a reference means for providing reference image data representative of the desired locations of the indicia relative to the screen, a comparison means for comparing the reference image data with the actual positions of the indicia within the images received by the at least one camera after the web has been advanced by the feeding means, and for generating longitudinal, lateral and angular difference data representative of the difference in position between the indicia within the image and the desired locations of the indicia, and a control means for receiving the longitudinal, lateral and angular difference data and operating the longitudinal, lateral and angular shifting means to change the alignment between the screen and the web to compensate for the difference in position between the indicia within the image and the desired locations of the indicia so that one of the defined areas of the web is positioned in the desired predetermined relationship with the screen

11 A registration system as recited in claim 10, wherein the feeding means is the longitudinal shifting means

12 A registration system as recited in claim 10, further comprising a pair of longitudinally spaced, laterally extending support bars on which the screen is supported for movement, each support bar being supported on the base for axial shifting movement in a direction transverse to the path of travel of the web, the lateral and angular shifting means including a pair of motors supported on the base, each motor having an axially shiftable output shaft connected to one of the support bars for shifting the support bar when the motor is energized such that lateral alignment between the screen and web is achieved by energization of both motors to shift the support bars relative to the base without shifting the bars relative to one another, and angular alignment is achieved by energization of the motors to shift the support bars relative to one another

13 A registration system as recited in claim 10, wherein the at least one camera includes a charge coupled device (CCD)

14 A registration system as recited in claim 12, wherein the at least one camera moves with the support bars 15 A registration system as recited in claim 10, wherein the reference means includes indicia affixed to the screen at positions which appear within the images received by the at least one camera

16 A registration system as recited in claim 12, further comprising a frame unit on which the screen is supported, wherein the support bars each include a pair of spaced vertical pins, and the frame unit includes structure defining a circular hole and three slots, each aligned with one of the pins of the support bars so that the frame is supported for movement with the support bars, the circular hole defining a vertical axis about which the frame unit is pivoted upon actuation of the angular shifting means to adjust the angular alignment between the screen and the web