Question MIamki CJV30 160 zig zag printing

turn on the printer in service mode (function+remote+power on). Go to function->#test->linear encoder, and do test at widths 200mm, 400mm, 600 mm etc. put here photos of the results.
check y-motor motion compensation setting. function ->#parameter-> comp Y

 

Had this issue happen a few times. Ended up replacing encoder but didn't need too. It ended up being the ribbon cable that connects from the carriage board to the print head. Check all connections going to print head, take them out and re-insert all connections.

 

I would change the encoder sensor. Usually when you see this pattern and the encoder strip doesn't fix it, it's the sensor.

 

I am surprised to see such test results for the first time. Usually in case of sensor malfunction (E), its data lags behind the motor data (M).
for example, with a dough width of 200, M=200.0 E=199.5; width of 400 M=400 E=399.0; width 1600 M=1600 E=1596.
In case malfunction encoder strip, the readings (M and E) change from one place on width.
Your sensor (E) results are growing. Either the sensor is broken or the problem is deeper.
Try clean sensor, maybe there is a hair or a bunch of dust.
check the gears on the Y-motor.
How printing in uni-dir mode?