For negative overprinting errors, the stroke of the aluminum foil may be increased, or the printing plate may be rotated by a certain angle along the running direction, so that the color mark is imprinted with dots. The centerline of the space is relatively "backward", so that the swatches are printed on the centerline.
The photoelectric scanner is the location of the full-track trace scan color code. During the scanning process, two pulse signals are generated to send the input circuit, and the input circuit converts the time difference of the two pulses to lag (or advance) to an error pulse having the error time width. This error pulse passes through the integration circuit and shows the actual overprint error. the size of. The output circuit starts the correcting motor operation to drive the adjustment roller to swing.
Quasi-deviation.
In the multi-color overprinting of aluminum foil, the tracking of the position of the color mark on the photoelectric scanner is performed by first turning on the main power switch of the automatic overprinting apparatus, turning on the control power of each channel computer and tracking the scanning power, and aligning the photoelectric scanning head with the reflecting plate. , adjust the distance between the near and far to minimize the light spot on the reflector. The detection distance at this time is approximately equal to the focal length of the photoelectric scanning head. Move the photoelectric scanning head left and right so that the light spot hits the center of the color mark. When the color scale of the color scale is higher than the gray level of the background color, the light-on/dark-out switch plate of the photoelectric scanning head is directed toward the dark (black dot) side. Optoelectronics is facing the color mark, adjust the switching threshold multi-turn potentiometer until the status indicator lights up. With the light spot facing the background, the multiturn potentiometer rotates in the black direction and the number of rotations is recorded until the status indicator lights up.
Reverse the multi-turn potentiometer back to half the number of cells, after the photoelectric scanner is adjusted, perform the overprint operation. At this time, the manual printing should be performed with the lowest possible printing line speed, so that each overprint color code enters its own corresponding Overprint space. The maximum allowable overprint error detection range is 18mm. It is better to be closer to the center of overprinting spaces. After manual overprinting, the printing line speed is increased to about 30 meters/minute. When the control panel has "line speed" and "overprinting error" displayed, it can be transferred to "automatic" control. When the automatic overprinting operation is normal, the machine speed can be gradually increased until the expected working line speed.
---- Printed in China
