1、Designation: F 577 03e1Standard Test Method forParticle Size Measurement of Dry Toners1This standard is issued under the fixed designation F 577; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number i
2、n parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEBetter quality figures were added in March 2004.1. Scope1.1 This test method covers aperture particle size analysisusing an electronic sensing zone
3、apparatus provided with adigital pulse processor. Dry inks, toners, and so forth, arecovered. Particles as small as 1 m and as large as 120 m canbe analyzed.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o
4、f 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 channela size subgroup that has been obtained bydividing the range of the analysis into
5、 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 distributionthe number size distribu-tion is measured and may be represented in a nu
6、mber percentcurve as differential, cumulative larger than or cumulativesmaller than. (Figs. 1-3).2.1.4 pulse (man height average) by sequencethe maxpulse height average is calculated from the pulses generatedduring the anaylsis (Fig. 4).2.1.5 median particle sizethe median size (50 % oversizeor unde
7、rsize) 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 distributionis calculated by the instruments software and may be repre-sented in a vo
8、lume 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 by causing them to flowthrough a small orifice on both sides of which are immersed
9、electrodes. 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 integrated in pulses. These pulses areprocessed yielding size and pulse distributions.
10、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 to theexpected particle size range.Aperture Diameter, m Particle Size Range, m50 1
11、to3070 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 Use4.1 This test is useful in determining particle size charac-teristics of dry ton
12、ers 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), equippedwith a minimum capability of 256 size channels, a digital pulseprocessor and 50,
13、 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 the dry toner in an aqueous electrolyte.1This test method is under the jurisdicti
14、on of ASTM Committee F05 on BusinessImaging Products and is the direct responsibility of Subcommittee F05.04 onElectrostatic Imaging Products.Current edition approved Jan. 10, 2003. Published March 2003. Originallyapproved in 1978. Last previous edition approved in 1983 as F 577 83 (1997).2The boldf
15、ace numbers in parentheses refer to the list of references at the end ofthe test method.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Reagents and Materials6.1 Electrolyte4 weight % aqueous sodium pyrophos-phate or 1 weight % so
16、dium chloride. The electrolyte shall beadequately 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 monosize
17、d spherical particles standardized for thenumber % 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 Distr
18、ibution Larger ThanF57703e127.2 Sample 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 qual
19、ity, one copy after the other. In 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 thesemico
20、hesive, electrostatic nature of the 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 SequenceF57703e13NOTE 2The above considerations tend to permit a pra
21、ctical assess-ment of quality 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 te
22、chniques, like sample splitters, 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-
23、brated with monosized latex polymer microspheres (3, 4)which have been standardized for the number % modal size.Calibration should be regularly verified to ensure the accuracyof calibration. For calibration and verification follow themanufacturers recommended procedure.FIG. 5 Differential Volume Siz
24、e DistributionFIG. 6 Cumulative Volume Size Distribution Larger ThanF57703e149. 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 manu
25、facturers instruction 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
26、 particles.9.4 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 from the beaker. Thirty seconds maximum sonicationat the wattage setting recommended has been found
27、 acceptable.9.5 Transfer 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 mechanically
28、stir the toner suspension 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 ad
29、visable to accumulate 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,
30、formation of aglomerates, 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 pre
31、vent contamination between 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
32、up the electrical sensing 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 nonion
33、ic surfactant (5). The 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
34、fracturing ofparticles from the beaker. Thirty seconds maximum sonicationat the wattage setting recommended has been found acceptable.10.5 Transfer the dispersed sample suspension to a largerborosilicate round-bottom beaker and dilute to 150 to 200 mLvolume with filtered electrolyte. Sample concentr
35、ations 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 andFIG. 7 Cumulative Volume Size Distribution Smaller ThanF57703e15mechanically stir the toner suspension for approxim
36、ately 1min. Use 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
37、 each analysisto 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-si
38、s.10.8 Using the 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 ins
39、truction manual. 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 th
40、e original sample 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 be
41、aker in the instrument 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. Ca
42、lculation11.1 No 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 fo
43、rth, in many cases 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 tow
44、ards the lower size 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 tot
45、he results obtained 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 electri
46、cal sensing zonemethod (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 mode
47、l Instruments A, 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 sizeF57703e16REFERENCES(1) Allen, T., Particle
48、Size Measurements, 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 forCali
49、brating Electrical Sensing Zone Methods,” Powder Technology,Amsterdam, Vol 13, 1976, pp. 37.(4) Alliet, D. F., and Behringer, A. J., “A Performance Reliability Study onthe Model C Coulter Counter in the Characterization of PolymericMaterials,” Particle Size Analysis, Proceedings of the Conference ofthe Society of Analytical Chemistry, London, 1970, pp. 353365.(5) Llody, P. J. “Coincidence Effects on Particle Size Analysis by CoulterCounter,” paper presented at Nurmberg Particle Conference, Sept.1719, 1975.(6) Kinsman, S., and Coulter, J. R., “Particle
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