ASTM_F_1425_-_06_2011.pdf

Designation:F142506(Reapproved 2011)Standard Test Method forDetermining the Tribocharge of Two-Component DeveloperMaterials1This standard is issued under the fixed designation F1425;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes a technique for measuringthe tribocharge or charge-to-mass ratio of a sample of devel-oper material.1.2 This test method determines the concentration of tonerin a sample of developer material.2.Referenced Documents2.1 ASTM Standards:2F335 Terminology Relating to Electrostatic Imaging3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 charge to mass ratiothe quantity of charge per unitof mass.In xerography,the tribocharge per unit of mass of thetoner.3.1.2 tribochargethe general term for the electric chargeof a material whose charge is created by the tribo electriceffect,or the rubbing of unlike surfaces together.3.2 Terms and definitions used in this test method may befound in Terminology F335.4.Summary of Test Method4.1 Two component developer materials used in the xero-graphic process are charged by the tribo electric effect.Xerographic developers are commonly made up of two mate-rials:toner and carrier.Toners are typically under 38 m in sizewhile carriers are several times larger.This size difference isused in the measurement of tribocharge.4.2 The sample cell contains a very fine screen(400 mesh),which allows toner to pass through and blocks carrier frompassing through.The sample cell is held in an insulated blockwith an electrical connection between the sample cell and theelectrometer.The electrometer measures the charge on the cellas the toner is blown off the carrier by a highpressure airstream.From the difference in weight of the cell before andafter the blow-off,and the electrometer charge measurement,the charge to mass ratio and percent toner concentration of thedeveloper material can be calculated.5.Significance and Use5.1 This test method measures a fundamental property of atoner and developer mix used in copiers and printers.This testmethod is used for quality control purposes and to determinethe ability of the toner and developer materials to develop ontothe photoreceptor.5.2 This test method may be used to measure the chargeto-mass ratio of new developer mixes.5.3 This test method may be used to measure the chargeto-mass ratio of developer material samples taken from a ma-chine.5.4 This test method may be used to measure the tonerconcentration of new developer mixes.5.5 This test method may be used to measure the tonerconcentration of developer material samples taken from amachine.6.Interferences6.1 Any differences in this test method used to charge thetoner that would effect the frequency of collisions of toner andcarrier,such as rolling the container of developer material in acontainer of different size or at a different rate,may causevariation in the results.6.2 Any differences in the material that the container used toroll the developer material is made from could cause variationsin the results.6.3 The environmental conditions(temperature,humidity)can effect the results because some toners and carriers absorbwater onto their surfaces.The water content of the compressedair can effect the results for hydroscopic materials.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 Oct.1,2011.Published September 2012.Originallyapproved in 1992.Last previous edition approved in 2006 as F142506.DOI:10.1520/F1425-06R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.4 The 400-mesh screen of the sample cell can becomeclogged with material.This is indicated by increasing cellweights.The clogged screen may be able to be cleaned byrunning a test with the cell empty or by blowing filtered airthrough the cell from a hand-operated nozzle.If the cellweights indicate that the cell is still clogged,the cell can becleaned in an ultrasonic cleaner.Be sure the cell is rinsed anddried before use.6.5 The 400-mesh screen can develop holes or gaps afterrepeated use.This is evidenced by high percent toner valuesindicating that the carrier particles have passed through the finescreen,giving lower after blow-off cell weights.7.Apparatus7.1 Sample Cell The sample cell contains a very finescreen(400 mesh)supported by a coarse screen.The finescreen allows tone