1、Designation: F 1425 06Standard Test Method forDetermining the Tribocharge of Two-Component DeveloperMaterials1This standard is issued under the fixed designation F 1425; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、material.1.2 This test method determines the concentration of tonerin a sample of developer material.2. Referenced Documents2.1 ASTM Standards:2F 335 Terminology Relating to Electrostatic Imaging3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 charge to mass ratiothe quantity o
4、f 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 met
5、hod may befound in Terminology F 335.4. 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
6、 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 conn
7、ection 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 ra
8、tio 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
9、 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
10、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 col
11、lisions 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 t
12、he 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.6.4 The 400-mesh screen of the sample cell can becomeclo
13、gged 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 air1This test method is under the jurisdiction ofASTM Committee F05 on BusinessImaging Products and is the direct responsibility o
14、f Subcommittee F05.04 onElectrostatic Imaging Products.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1992. Last previous edition approved in 2001 as F 1425 92 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Serv
15、ice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.through the cell from a hand-operated nozzle
16、. 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
17、 particles have passed through the finescreen, giving lower after blow-off cell weights.7. Apparatus7.1 Sample CellThe sample cell contains a very finescreen (400 mesh) supported by a coarse screen. The finescreen allows toner to pass through and blocks carrier frompassing through. See Fig. 1.7.2 Tr
18、ibometer, any device which provides the functions ofholding the cell in the proper electrical connection, blowing theair through the cell under controlled conditions of air pressureand time, and collecting the waste toner. See Fig. 2.7.3 Vacuum Cleaner, of a type used in copier servicesuitable for r
19、emoval of toner (fine particle filter).NOTE 1The hose should be made of material which is resistant totoner, if possible. The vacuum cleaner is used to remove the waste toner.37.4 Electrometer, capable of measuring charge in the rangefrom 108to 106C.47.5 Air Supply Line, capable of supplying air at
20、a minimumflow rate of 1.6 to 2.0 ft3/min at 100 psi. The air supplied mustbe filtered to be free of particulate matter as well as oil (mostindustrial air systems supply air which includes a minuteamount of oil used as a lubricant in air-operated equipment).A5-m pre-filter and oil coalescing filter w
21、ill remove particlesand oil. Either the air supply line, or the tribometer unit mustinclude an air-pressure regulator.7.6 Analytical Balance, capable of weighing the cell (ap-proximately 85 g) to 0.0001 g.7.7 Roller UnitA two-roll device where one roll is pow-ered by a motor. The sample container is
22、 placed on the tworollers such that when the roller is powered, the samplecontainer rolls on top of the two rollers. The roller unit shouldbe capable of rolling several sizes of containers of developer,and have a variable speed motor with enough torque to rollsamples, or developer mixed of weights a
23、ppropriate to theapplication. See Fig. 3.8. Sample Preparation8.1 Roll commercially prepared developer mixes or previ-ously prepared large batches for at least 30 min at theappropriate speed for the size of the container.8.2 Roll freshly made large batches for at least 4 h at theappropriate speed fo
24、r the size of the container.8.3 Prepare small carrier/toner samples (approximately 100g) in a glass jar and roll for at least1hattheappropriate speedfor the size of the container.8.4 Run samples taken from a copy machine as soon aspossible. Take the sample after the machine has been turningthe devel
25、oper unit for at least 10 min, so that the toner has hadan opportunity to tribocharge.8.5 All speeds are relative to the container size. The actualsurface speed of the containers in all cases is approximately 90ft/min.9. Calibration9.1 Initially, make a series of measurements of a developermaterial
26、to determine the sample size, air pressure, and timerequired to completely remove the toner from the carrier for thetribometer device being used. Use these standard conditions forall similar samples. For typical negative toners, a 3-g developer3The sole source of supply of the apparatus (vacuum clea
27、ner 3M Model 496 AG) known to the committee at this time is 3M, 3M Center, St. Paul, MN551441000. If you are aware of alternative suppliers, please provide this informa-tion to ASTM International Headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical
28、committee,1which you mayattend.4The sole source of supply of the apparatus (Keithley 610C electrometer) knownto the committee at this time is Keithley Instruments Inc., 28775 Aurora Road,Cleveland, OH 44139. If you are aware of alternative suppliers, please provide thisinformation to ASTM Internatio
29、nal Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.FIG. 1 Sample CellFIG. 2 TribometerF1425062sample requires 60 psi of air pressure for 120 s yieldingcharge-to-mass ratios of 5 to 25 C/g for 3 to 4 % tonerconcen
30、tration.9.2 On a regular basis, such as every 20 samples, or after theinstrument has not been used for more than one month, checkthe instrument by measuring the charge-to-mass ratio and tonerconcentration of a known developer mix. Any differences inthe measurements of the known developer mix could i
31、ndicatethe need for maintenance.9.3 Test the fit of the new screens by performing a test withonly carrier material in the cell. The before and after cellweights should be the same if the screens have been properlyinstalled. This procedure can also be used to verify that screensneed to be replaced.10
32、. Procedure10.1 Set the electrometer controls as follows:10.1.1 Polarity, + or as required. (Meter polarity dependson material.)10.1.2 Range, from 106to 108C.10.1.3 Refer to the electrometers instruction manual fordetailed operating instructions.10.2 Install the vacuum cleaner hose where appropriate
33、 toremove the waste toner.10.3 Set the pressure reducer valve so that the air pressurethrough the cell is 60 psi.10.4 Set the tribometer instrument to deliver the air for a settime period. A typical negative toner requires 120 s to removethe toner from the carrier. The time required can be determine
34、dby repetitive measurements of the same sample. When noadditional weight loss is detected, the time to remove all thetoner from the sample has been determined.10.5 Weigh the clean cell on an analytical balance to thenearest 0.0001 g. Record the weight under Item A on the datasheet.10.6 Add enough de
35、veloper material so that the amount oftoner expected to be in the sample is large enough to beweighed accurately. Typically, approximately3gofdeveloperis added to the cell and reweighed. Record this weight underItem B on the data sheet.10.7 Assemble the cell, taking care not to lose any material.10.
36、8 Place the cell in the cell holder and close the unit.10.9 Ready the electrometer controls.10.10 Turn on the vacuum cleaner, and then turn on the airsupply. The electrometer should show an immediate response.Turn off the air and vacuum cleaner after the appropriate timeperiod if the tribometer does
37、 not automatically shut them off.10.11 When the test is complete, record the electrometerreading on the data sheet under Item D. Note that theelectrometer measures the residual charge on the cell after thecharged toner is removed. The electrometer reading will beopposite in sign to the charge on the
38、 toner.10.12 Open the unit, remove the cell. Do not clean off theresidual toner on the surface of the cell. Weigh the cell. Recordthis weight under Item C on the data sheet.10.13 Open the cell, empty it out, and holding both halvesso that the open ends are facing down, bang the halves togetherto rem
39、ove the last traces of material. Alternatively, blow airthrough the cell halves. The cell is clean when it weighs thesame as the empty weight (A) on the data sheet.11. Calculation11.1 Calculate the charge-to-mass ratio (Q/M) as follows:Q/M 52D/10F 5 C/gwhere F=BC.11.2 Calculate the apparent toner co
40、ncentration as follows:F/E! 3 100 5 % tonerwhere E=BA.12. Interpretation of Results12.1 For any two component developer samples, the tribo-charge (charge-to-mass ratio) is created by the frictionalrubbing of the toner and carrier surfaces. The sample prepara-tion plays an important role in the measu
41、red tribocharge value.FIG. 3 Roller UnitFIG. 4 Sample Data SheetF1425063Samples must be allowed to fully charge before the measure-ment is performed or false low values will result.Additionally,when comparing two samples, their charging history must betaken into account.12.1.1 For two component deve
42、lopers, tribocharge is afunction of the concentration of toner in the developer sample.At very high toner concentrations, there is more toner than thesurface of the carrier can interact with. This condition leads tolower tribocharge values.12.2 The quality of a used developer can be inferred from ac
43、omparison of the tribocharge value of the test developer andthe tribocharge value of a fresh developer at the same concen-tration.12.2.1 If both samples are similarly prepared, a lowertribocharge value could indicate that the used developerscarrier is partially impacted with toner, thereby reducing
44、thecarrier surface area that can participate in charging. A highertribocharge value, accompanied by lower print density couldindicate that the used developer is contaminated with asubstance that can effectively compete with the toner atdevelopment.12.2.2 If the used developer sample was charged in a
45、developer unit, and the fresh developer sample was charged byrolling, a lower tribocharge value for the used sample couldalso indicate that the developer unit does not provide adequatemixing.13. Precision and Bias13.1 Repeated measurements of the same developer sample,measured over many days in one
46、laboratory gives a standarddeviation of 0.62 C/g for a charge-to-mass ratio of 12.60C/g, and 0.35 for a percent toner of 3.48 %.14. Keywords14.1 developer; tribo; tribocharge; two componentsASTM International takes no position respecting the validity of any patent rights asserted in connection with
47、any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technic
48、al committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration
49、 at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail);
