ASTM F577 - 03(2009) Standard Test Method for Particle Size Measurement of Dry Toners (Withdrawn 2017).pdf

1、Designation: F577 03 (Reapproved 2009)Standard Test Method forParticle Size Measurement of Dry Toners1This standard is issued under the fixed designation F577; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revisi

2、on. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers aperture particle size analysisusing an electronic sensing zone apparatus provided with adigital pulse pr

3、ocessor. Dry inks, toners, and so forth, arecovered. Particles as small as 1 m and as large as 120 m canbe analyzed.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafe

4、ty concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 chan

5、nela size subgroup that has been obtained bydividing the range of the analysis into a certain number of sizecategories. The resolution of the analysis is increased when thenumber of channels is increased.2.1.2 dynamic rangethe ratio between the upper andlower limit of an analysis.2.1.3 number size d

6、istributionthe number size distributionis measured and may be represented in a number percent curveas differential, cumulative larger than or cumulative smallerthan. (Figs. 1-3).2.1.4 pulse (man height average) by sequencethe maxpulse height average is calculated from the pulses generatedduring the

7、anaylsis (Fig. 4).2.1.5 median particle sizethe median size (50 % oversizeor undersize) is a convenient value for the central tendency ofa size distribution curve. For a distribution derived by numberof particles, it is called the number median size.2.1.6 volume size distributionthe volume size dist

8、ributionis calculated by the instruments software and may be repre-sented in a volume percent curve as differential, cumulativelarger than or, cumulative smaller than. (Figs. 5-7).3. Summary of Test Method3.1 This technique (1)2determines the number and size ofparticles suspended in an electrolyte b

9、y causing them to flowthrough a small orifice on both sides of which are immersedelectrodes. Voltage pulses, whose amplitudes are proportionalto the particle volumes, are generated by changes in resistanceas the particles pass through the orifice. The signal generated isscanned, digitized and integr

10、ated in pulses. These pulses areprocessed yielding size and pulse distributions. The pulse datais saved and may be reprocessed at a later time for a differentanalysis range or resolution.3.2 This test method covers the size range from 2 % to 60 %of the aperture diameter chosen as being appropriate t

11、o theexpected particle size range.Aperture Diameter, m Particle Size Range, m50 1to3070 1.4 to 42100 2.0 to 60140 2.8 to 84200 4 to 200For broader size ranges two aperture tubes may be used andboth results are combined by the instruments software into asingle size distribution.4. Significance and Us

12、e4.1 This test is useful in determining particle size charac-teristics of dry toners used in electrostatic imaging devicessuch as copiers and laser printers. It is a practiced method foruse in quality control of toner particle size.5. Apparatus5.1 Electrical Sensing Zone Instrumentation (2), equippe

13、dwith a minimum capability of 256 size channels, a digital pulseprocessor and 50, 70, 100, 140, or 200-m aperture tubes.5.2 Software, capable of processing the pulse data to yieldsize distribution graphs and statistics.5.3 Ultrasonic Dispersing Probe , or alternative equipmentsuitable for dispersing

14、 the dry toner in an aqueous electrolyte.1This test method is under the jurisdiction ofASTM Committee F05 on BusinessImaging Products and is the direct responsibility of Subcommittee F05.04 onElectrostatic Imaging Products.Current edition approved Feb. 1, 2009. Published February 2009. Originallyapp

15、roved in 1978. Last previous edition approved in 2003 as F577 031. DOI:10.1520/F0577-03R09.2The boldface numbers in parentheses refer to the list of references at the end ofthe test method.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Stat

16、esNOTICE: This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International (www.astm.org) for the latest information16. Reagents and Materials6.1 Electrolyte4 weight % aqueous sodium pyrophos-phate or 1 weight % sodium chloride. The electrolyte shall bea

17、dequately filtered to remove almost all particle contaminantsgreater than 1 m. Some aqueous electrolytes are commerciallyavailable.6.2 Surfactanta nonionic surface active agent suitable forkeeping toner particles separated while in suspension.6.3 Near monosized spherical particles standardized for t

18、henumber % modal size as calibration standards.37. Sampling7.1 Sample the powder when flowing (1).3The standardized particles are usually available from the equipment manufac-turer.FIG. 1 Differential Number Size DistributionFIG. 2 Cumulative Number Size Distribution Larger ThanF577 03 (2009)27.2 Sa

19、mple the entire powder flow over small intervals oftime. This is preferable to a continuous withdrawal of a smallfraction of the flow.7.3 A further positive aspect is that electrostatic imagingrequires material that produces uniform, stable, and acceptableimage quality, one copy after the other. In

20、general, the usagerate is in the range from 1 to 100 mg per copy, depending onthe original document and the electrostatic conditions. Eachcopy, consequently, contains a small sampling of the bulktoner.NOTE 1Often the processes used to produce dry toner and thesemicohesive, electrostatic nature of th

21、e fine material can make itprohibitively difficult to follow these important general rules for powdersampling.FIG. 3 Cumulative Number Size Distribution Small ThanFIG. 4 Max Pulse Height Average by SequenceF577 03 (2009)3NOTE 2The above considerations tend to permit a practical assess-ment of qualit

22、y by the measurement of a number of small samples takenfrom various sections of nonmoving powder beds and containers. Thesesamples may be obtained by probes, also known as “thieves,” for whichmany designs exist. In fact, this method is often preferable to moreelaborate techniques, like sample splitt

23、ers, which have moving parts. Suchdevices are difficult to maintain, and may have places where the thermallysensitive powder is fused by shear to form large, undesirable aggregates.8. Calibration and Standardization8.1 The electrical sensing zone equipment should be cali-brated with monosized latex

24、polymer microspheres (3, 4)which have been standardized for the number % modal size.Calibration should be regularly verified to ensure the accuracyFIG. 5 Differential Volume Size DistributionFIG. 6 Cumulative Volume Size Distribution Larger ThanF577 03 (2009)4of calibration. For calibration and veri

25、fication follow themanufacturers recommended procedure.9. Procedure for Toner Samples within 1:30 DynamicSize Range9.1 Select the appropriate aperture from 3.2 according to thesize range of the sample.9.2 Set up the electrical sensing zone apparatus in accor-dance with the manufacturers instruction

26、manual.9.3 Measure approximately 5 to 10 mg of toner into a50-mL borosilicate beaker filled with filtered electrolyte, andadd 1 or 2 drops of filtered nonionic surfactant(5) . The amountof toner used in an analysis is very important if the material hasa high percentage of finer particles.9.4 Fully d

27、isperse the toner in the electrolyte-surfactantmixture using an ultrasonic probe at approximately 6 W power.Care should be taken in sonication to avoid the fracturing ofparticles from the beaker. Thirty seconds maximum sonicationat the wattage setting recommended has been found acceptable.9.5 Transf

28、er the dispersed sample suspension to a largerborosilicate round-bottom beaker and dilute to 150 to 200 mLvolume with filtered electrolyte. Sample concentrations shouldnot exceed the level recommended by the manufacturer.9.6 Place the sample on the sensor stand and mechanicallystir the toner suspens

29、ion for approximately 1 min. Take carehere to avoid cavitation and air bubbles. Erroneous largeparticle counts can cause a shift in the volume size distributionif this procedure is not carefully followed.9.7 Measure at least three samplings of the particle suspen-sion. It is advisable to accumulate

30、at least 50 000 counts ineach analysis to ensure good statistical precision.9.8 Overlay the max high average pulse distribution graphsfor the three samples and verify that all of them were stablethrough the analysis. If the sample was not stable in any of theanalyses, that is, formation of aglomerat

31、es, repeat the analysis.9.9 Using the instruments software, average the threeresults and report the resulting number as the parameter beingmeasured.9.10 Clean all glassware and thoroughly rinse the orificetube externally with clean electrolyte between measurements.This will prevent contamination bet

32、ween analyses and keepnoise level at an acceptably low level.9.11 Repeat 9.3 through 9.11 using a second sampling of thetoner.10. Procedure for Toner Samples with Larger than 1:30Dynamic Size Range10.1 Select two apertures from 3.2 to cover the size range ofthe sample.10.2 Set up the electrical sens

33、ing zone apparatus in accor-dance with the manufacturers instruction manual for the largerof the two apertures selected in 10.1.10.3 Measure approximately 5 to 10 mg of toner into a50mL borosilicate beaker filled with filtered electrolyte, andadd 1 or 2 drops of filtered nonionic surfactant (5). The

34、 amountof toner used in an analysis is very important if the material hasa high percentage of finer particles.10.4 Fully disperse the toner in the electrolyte-surfactantmixture using an ultrasonic probe at approximately 6 W power.Care should be taken in sonication to avoid the fracturing ofparticles

35、 from the beaker. Thirty seconds maximum sonicationat the wattage setting recommended has been found acceptable.FIG. 7 Cumulative Volume Size Distribution Smaller ThanF577 03 (2009)510.5 Transfer the dispersed sample suspension to a largerborosilicate round-bottom beaker and dilute to 150 to 200 mLv

36、olume with filtered electrolyte. Sample concentrations shouldnot exceed the level recommended by the manufacturer.10.6 With the larger of the two selected apertures installedin the instrument, place the sample on the sensor stand andmechanically stir the toner suspension for approximately 1min. Use

37、caution to avoid cavitation and air bubbles. Erroneouslarge particle counts can cause a shift in the volume sizedistribution if this procedure is not carefully followed. Measureat least three samplings of the particle suspension. It isadvisable to accumulate at least 50 000 counts in each analysisto

38、 ensure good statistical precision.10.7 Overlay the max high average pulse distribution graphsfor the three samples and verify that all of them were stablethrough the analysis. If the sample was not stable in any of theanalyses, that is, formation of agglomerates, repeat the analy-sis.10.8 Using the

39、 instruments software, average the threeresults and save the resultant size distribution.10.9 Remove the sample beaker and the larger aperture.Install the smaller aperture and set up the electrical sensingzone apparatus for the smaller aperture in accordance with themanufacturers instruction manual.

40、 Transfer the sample sus-pension to a clean second beaker passing all of it through anappropriate large particle-scalping screen to remove particleslarger than the upper size range for the smaller aperture butleaving particles overlapping part of the range for bothapertures. Flush the original sampl

41、e beaker with clean electro-lyte. Transfer the entire flushing electrolyte to the secondbeaker passing it through the scalping screen. Further flushdown the scalping screen into the second beaker to get as manysample particles through the screen as possible. Place thesecond sample beaker in the inst

42、rument and using the smallaperture repeat 10.6 through 10.8.10.10 Open the files for the averaged size distribution fromthe tow apertures; merge both in a single size distribution usingthe instruments software.10.11 Repeat 10.3 through 10.10 using a second sampling ofthe toner.11. Calculation11.1 No

43、 manual calculations are necessary; all measuredparameters are automatically calculated by the instrumentssoftware.12. Interpretation of Results12.1 The most common ways to display particle size distri-butions are number % and volume %; the values for the mean,meidan, mode, and so forth, in many cas

44、es will be totallydifferent. A number size distribution reflects the percentage ofthe particle population in different size categories. In general,most powder grinds have more fines than large and because ofthis, the graphs for the number size distribution have atendency to shift towards the lower s

45、ize of the distribution (Fig.1). A volume % size distribution reflects the percentage of theparticle volume in different size categories. Sinc ethe largerparticles have the most volume displacement, the graph will beshifted to the larger sizes (Fig. 5). This graph is very similar tothe results obtai

46、ned from running a sample through a sieve set.If the relative number of fine particles in a powder will affectthe quality of a product, it will be advisable to report the resultsof size analyses as a number distribution.13. Precision and Bias13.1 The precision and bias of the electrical sensing zone

47、method (4, 6, 7) have been reported in the referenced scientificliterature.13.2 An example of the precision obtained for dry tonerbased on triplicate measurements of the mean value of the sizedistribution is shown in Table 1. Analyses were done on fivedifferent units of the same model Instruments A,

48、 B and C werein a different location from instruments D and E. The unit ofmeasurement was microns (m).13.3 It is not difficult to obtain this level of precision if theprocedure is carefully followed.14. Keywords14.1 dry toners; particle sizeF577 03 (2009)6REFERENCES(1) Allen, T., Particle Size Measu

49、rements, 2nd Edition, Chapman andHall, Ltd., London, 1975.(2) Allen, T., and Marshal, K., The Electrical Sensing Zone Method ofParticle Size Measurement, Bibliography, published by University ofBradford, England, 1972.(3) Alliet, D. F.,“ A Study of Available Particle Size Standards forCalibrating Electrical Sensing Zone Methods,” Powder Technology,Amsterdam, Vol 13, 1976, pp. 37.(4) Alliet, D. F., and Behringer, A. J., “A Performance Reliability Studyon the Model C Coulter Counter in the Characterization of PolymericM