1、Designation: F 470 89 (Reapproved 2003)Standard Practice forCaking Temperature of Dry Electrostatic Toner1This standard is issued under the fixed designation F 470; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 practice covers the determination of the tempera-ture at which a dry toner will cake as storage temperatures areraised
3、1.2 In certain cases the effects of pressure or pressurecombined with heat can cause blocking and caking of a drytoner. This recommended practice does not provide for evalu-ation of such pressure effects.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wit
4、h 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. Summary of Practice2.1 This practice consists of testing samples at controlledtemperatures and evaluating t
5、hem for any sign of blocking aftera specified period.3. Significance and Use3.1 Dry toners for use in electrostatic copiers and printersare normally free-flowing powders at room temperatures. Theyare often formulated to fuse at elevated temperatures as part ofthe electrostatic printing and copying p
6、rocess. The specifictemperature at which fusing takes place has implications ofpremature change in the physical characteristics of a giventoner, defined as blocking or caking. This is undesirable, butcan result when the dry toner is subjected to temperatures in therange of its fusing point during co
7、nditions of transport, storage,or local handling; as well as to the environmental parameters ina given location after the product is introduced and held for usein the machine reservoir itself.4. Apparatus4.1 Circulating Air Oven, forced, provided with a thermom-eter and capable of being set at vario
8、us temperatures and ofremaining at 6 1C over a range from 40 to 80C.4.2 Weighing Dishes, round, aluminum, approximately 60mm in diameter and 17 mm deep.4.3 Balance, capable of weighing 10 g with a precision of0.1 g.4.4 Spatulas, Tongs, etc.5. Procedure5.1 Set the oven to remain at 40C.5.2 In separat
9、e aluminum weighing dishes, weigh twosamples each of 5.0 g of toner and, using a spatula, spread thesamples evenly over the dish bottoms. Provide the dishes withsuitable covers.5.3 Place one covered dish and sample in the oven, close toits center, and leave at 40C for 24 h. Keep the other sample atr
10、oom temperature.5.4 Remove the dish and sample from the oven, allow tocool, examine visually, stir with a spatula, and look for anyevidence of caking. Use the room temperature sample forcomparison purposes.5.5 If the oven-treated sample shows any evidence ofclumping, record its blocking temperature
11、as below 40C. If noevidence is noted, set the oven for 45C and repeat with a freshsample of toner. Repeat the test at 5C increments until thecaking temperature is determined. If the sample does not cakebefore or at 80C, record its blocking temperature as above80C.6. Report6.1 Report the blocking tem
12、perature or the caking tempera-ture.7. Precision7.1 When this practice is used to compare two or moretoners within a laboratory, the comparable ranking order isrepeatable. Because the interpretation of results is dependentupon the subjectivity of the observations, reproducibility be-tween laboratori
13、es may not be possible.8. Keywords8.1 caking temperature; dry toners; electrostatic toners1This practice is under the jurisdiction of ASTM Committee F05 on BusinessCopy Products and is the direct responsibility of Subcommittee F05.04 onElectrostatic Copy Products.Current edition approved Oct. 27, 19
14、89. Published December 1989. Originallypublished as F 470 76. Last previous edition F 470 85.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.ASTM International takes no position respecting the validity of any patent rights asserted i
15、n connection with 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 r
16、esponsible technical 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 car
17、eful consideration 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 Internation
18、al, 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); or through the ASTM website(www.astm.org).F 470 89 (2003)2
