Abstract: The transmitting and receiving sections are both energized, and the output of the transmitting section is connected to the input of the receiving section. The intensity of the transmitting section light source is varied, as by opening and closing a switch, and if the output of the receiving section is accurate in response to the light source variation, the transmitting and receiving sections are judged to be operating normally.

Abstract: A wet developer for use in electrophotography which consists of a carrier liquid having electric resistance of 10.sup.9 .OMEGA. . cm or more and dielectric constant of less than 3 and containing colored particles with a particle size of about 0.1 .about. 10 .mu., said particles being substantially insoluble in said carrier liquid, possessed of properties of solid matter and showing a distinct polarity within said carrier liquid, coupled with adhesive suspended particles with a particle size of about 0.01 .about. 10 .mu. which show the same polarity as said colored particles.

Abstract: Derivatives of polyglutamic acid with a molecular weight of from 1,000 to 100,000 and having the following general formula (I) are novel photoconductive substances which are superior in film forming ability and are suitable for use as photoconductors for electrophotographic copying materials:General formula (I) ##EQU1## wherein R represents a polynuclear aromatic or a heterocyclic nitrogen group, each containing up to sixteen carbon atoms, andn is the integer 1 or 2.