ASTM D4949-94(2002)

Paper generally is considered to be a material having good electrical insulating characteristics; for example, relatively high resistivity when dry. However, in certain applications, control of electrical resistivity to within specified limits is an important function, and resistivity measurement techniques are required.

While it is possible to measure resistivity using a variety of instruments (Test Methods D 257), this test method is specific for the Keithley Model 6105 resistivity adapter.⁶ The precision statement was based on the use of that instrument. Studies have shown that results will vary depending upon the type of resistivity adapter used and if reproducibility between different instruments in the same laboratory or between different laboratories is to be achieved, it is essential that the same model resistivity adapter be used in each determination.

The power supply and electrometer referred to in this method are manufactured by Keithley and the procedure describes their use. It is believed that comparable equipment manufactured by others would serve the same purpose. The precision statement was developed with Keithley equipment.

The control of resistivity is of special importance on high-speed nonimpact printing machines where that characteristic will affect printing, machine feeding and handling, or both. Resistivity is important in the image transfer function of a nonimpact printer or copier using the electrophotographic process. Resistivity is an important factor in controlling static buildup on high-speed nonimpact printers and copiers.

1.1 This test method describes the procedure for determination of both surface and volume (bulk) d-c resistivity of writing paper. This test method is specific for the Keithley 6105 resistivity adapter.

1.2 This test method has been developed as a special case for use on writing papers processed in high-speed nonimpact printers where resistivity control is critical. It is not in conflict with Test Methods D 257.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.