Quality Control System

at the Milwaukee Journal Sentinel

Standard Operating Procedure (SOP)

Duke Water Pick-Up Test

Reference Material:

1.  D-10 Ink-Water Emulsification Instrument Operator’s & Maintenance Manual

2.  US Ink SOP #09LQC09 and #09LIM14

Calibration:

1.  The following should be performed prior to testing a shipment of ink.

2.  Check the following items:

a.  Bowl Flatness. Rock bowl back and forth on a flat surface to ensure a flat bottom.

b.  Bowl Damage. Check bowl for any dents or out of roundness. Check the inside of bowl for any scratches

Preparing for Test:

1.  Be sure that the switch on the front of the testing device is turned off until Step 6 of the Performing the Test section. The main power at the back of the machine may be left on.

2.  Obtain following items prior to conducting test:

a.  Duke Ink-Water Emulsification Tester

b.  Plastic spatula (for working the ink)

c.  Cleaning rags and solvents

d.  Duke testing bowl

e.  Plastic beaker

f.  Test ink

g.  Pre-made Fountain Solution. This material should be made by hand and not taken from the Technatran Delta cabinets. Pre-made solution should not be let to set for longer than 2 weeks or if the conductivity should change by 100 micromhos or more from the time of original mixing.

h.  Laboratory scale (+/- 0.1grams)

3.  Place some of test ink on to the glass and work out any air bubbles with a spatula.

4.  Clean the Duke testing bowl and blades

5.  Program the device to the required testing time period. See table below for times

a.  Press the “Next Digit” on the control manual to highlight the digit.

b.  Once the digit is flashing, press the to adjust the pre-set value in the device.

c.  Once the setting has been entered, Press the “Enter” button to the value into memory.

d.  Press the “Reset” button to activate counter.

Black / Cyan / Magenta / Yellow
Time / 10 min. / 5 min / 5 min / 5 min

Performing the Test:

1.  Measure out 50.0 grams of pre-mixed fountain solution into a plastic beaker. Be sure to zero out the plastic beaker prior to filling with solution.

2.  Weigh in the Duke testing bowl 50.0 grams of test ink. . Be sure to zero out the Duke testing bowl prior to filling with ink.

3.  Place mixing blades into bowl and zero out the scale.

4.  Put the testing bowl into the turntable and then insert the mixing blades into their holders.

5.  Verify counter is set correctly

6.  Lower mixer head into testing position and turn on device on.

7.  Allow the mixer blades to completely coat the blades and bottom of bowl for approximately 5 revolutions.

8.  Quickly pour the 50.0 grams of fountain solution in the mixing bowl.

9.  An alarm will sound when the device has performed the task based upon the pre-set time.

10.  Disengage the blades from the testing unit and leave them in the testing bowl.

11.  Carefully pour off any extra fountain solution which was not absorbed by the ink into a plastic beaker.

12.  Slowly rotate the blades by hand in the testing bowl for a few seconds.

13.  Repeat step #11.

14.  Place the testing bowl, mixing blades, ink/fountain solution mixture on the laboratory scale and note the weight.

15.  To calculate the mount of water emulsification by the ink, take the weight from Step #14; multiply it by a factor of 2. A factor of 2 is being used due to the test is on a 100 gram basis.

Example: Scale reading was 25 grams

Water Pick-up Value: 25 x 2 = 50%

16.  Record measurements in to the Ink Testing Workbook.

17.  Clean all items used during testing.

18.  Any left over test ink should be stored in the storage cabinet in the Quality Control Lab as a reference.

Duke.SOP.doc; Rev. 1 1 of 2 3/17/2005