W48- Leaflet | Set-off 2 fields
Set-off 2 fields
AMSTERDAM - Multi-purpose printability tester
Version 2022-09
Principle
A strip of the substrate to be tested is printed with an offset ink. After specific times the strip is brought into contact with a blank strip of a set-off reference (counter) paper. Part of the ink, which is still present at the surface of the printed strip, will set-off on the reference (counter) paper. The more ink is absorbed into the printed strip, the less ink will transfer to the counter strip. The amount of the transferred ink is a value for the set-off.
Method of operation
Standards
This methode had been standardized internationally in e.g. ISO/TS 19857:2021
Materials
- [402.331.412] Printing disc aluminium, pin, 50 mm (2x)
- [404.520.068] IGT Set-off ink blue
- [404.001.005] Paper packing, 55 mm
- [404.009.029] IGT C2846 reference paper (counter paper)
- [466.000.710] IGT High Speed Inking Unit (HSIU)
- [466.003.003] Top roller 4 segments for conventional inks
- [408.000.200] IGT ink pipette 0,01 ml resolution
- 5 strips of substrate to be tested, dimensions 55 x 340 mm
- lint free rags
- ethanol or cleaning naphtha
- spectrophotometer if required
Testing conditions
Standard test atmosphere according to ISO 187 (23,0 ± 1,0 °C and 50 ± 2% RH)
Sample Conditioning
Be aware of the fact that a different way of conditioning of the samples can have influence on the results.
Standard settings
Amsterdam – Multi-purpose printability tester
- Printing speed: constant, 0,7 m/s
- Printing force: 1.000 N
- Ink film thickness 4,0 µm
- Timer between print / set-off at choice
- Camera lamp: n/a
- Checkbox Scan: n/a
IGT High Speed Inking Unit (HSIU)
- Water bath: 23 °C (73,4 °F)
- Mode 2:
- Start-up time [10 s]
- Distribution time 1 [20 s] | Distribution speed 1 [0,5 m/s]
- Inking time discs [15 s]
Preparation
- Cut paper strips of 55 x 340 mm and mark with top and/or bottom side, machine and/or cross direction and a code for the paper.
- Mount the packing on the sector of the Amsterdam printability tester.
- Mount the strip of paper to be tested over the packing.
- Shorten a strip of C2846 set-off paper to a length of 200 mm and mount on one of the aluminium printing discs with adhesive tape.
- Observe the correct position of the seam in relation to the starting position: the beginning of the strip of set-off paper should be closest to the pin at the back of the disc. Keep in mind the disc rotates clockwise.
- Place this disc on the second shaft of the Amsterdam printability tester.
- Select the method Set-off 2 fields and set the timer to the desired interval between print and second set-off.
- If the penetration of an ink must be tested, a standard paper C2846 will be printed with the ink to be tested. Otherwise, the test is carried out as described in this information leaflet.
- Fill the ink pipet with IGT set-off ink.
- Set the High Speed Inking Unit to Mode 2 and apply 4,0 µm (= volume 0,17 ml) ink on one of the four segments and start inking.
Execution
- Take the inked disc from the inking unit and place on the first printing shaft of the Amsterdam.
- Touch the button PRINT to rotate the sector and the 1st printing shaft into the start position.
- Press both side buttons to make a print and a set-off print and to come into the end position; then release the side buttons.
- Remove the printed strip from the sector.
- Remove the set-off print from the second printing disc.
- Clean the printing disc.
- Repeat all of the above for at least another 4 prints.
- Store the printed strips in the standard atmosphere at a safe place so that it cannot be damaged for at least 4 hours.
Cleaning
- Clean the discs with lint-free rags and naphtha.
- Clean all rollers of the inking unit, including the metal ones with lint-free rags and naphtha.
- Make sure the Amsterdam is clean and if necessary clean with some ethanol or cleaning naphtha on a lint free rag.
Assessment
- 4 hours after making the print measure the printed and set-off strips with the spectrophotometer.
- Calculate the average of the measured results per set-off time per type of paper.
Set-off 2 fields: print and counter print
NOTES
- When standard settings are used at 0,7 m/s, the first set-off is always made after 0,1 s, timer 2 sets the time for the second set-off field.
- Due to drying of the ink, it is not advised to add some ink to the same segment of the inking unit after a test. Clean the used segment first or choose the next segment of the top roller.
- IGT Set-off ink blue: Shelf stock time: 3 years | open time: 1 year.
Randstad 22 - 02
1316 BX Almere
The Netherlands
P.O.box 22022
1302 CA Almere
The Netherlands
