Selective removal of photoreceptor coatings by ultrasonification
View Patent ↗A method for recycling photoconductors is disclosed. In this method, the charge transport layer is selectively removed from the photoconductor without adversely affecting the electrical properties of the charge generating layer. The recycled drum may then be recoated with a new charge transport layer and reused in an electrophotographic process. In this method, the photoconductor to be recycled is placed in a specifically selected solvent, such as a dibasic ester, and is subjected to ultrasonic energy, preferably for a period not to exceed about 15 minutes.
1. A method for selectively removing the charge transport layer from a photosensitive drum without damaging the charge generation layer on said drum, comprising the steps of:
immersing the drum in a solvent selected from dibasic esters, aromatic solvents, acetone and mixtures thereof; and
applying ultrasonic energy, for a period not to exceed about 30 minutes, to said drum while it is immersed in the solvent.
2. The method according to claim 1 wherein the ultrasonic energy is applied in a range of from about 300 to about 500 watts/ft 3 .
3. The method according to claim 2 carried at a temperature of from 25° C. to about 65° C.
4. The method according to claim 3 wherein the ultrasonic energy is applied for no more than about 15 minutes.
5. The method according to claim 4 wherein the solvent comprises dibasic esters.
6. The method according to claim 5 wherein the solvent comprises dimethyl succinate.
7. The method according to claim 5 wherein the solvent is a mixture of dibasic esters comprising dimethyl succinate.
8. The method according to claim 5 wherein the ultrasonic energy is applied for from about 5 minutes to about 10 minutes.
9. The method according to claim 7 wherein the ultrasonic energy is applied for from about 5 minutes to about 10 minutes.
10. The method according to claim 4 wherein the solvent is selected from the group consisting of dimethyl succinate, acetone, toluene, xylene, and mixtures thereof.
11. The method according to claim 10 wherein the charge generating layer of said drum has a polyvinyl butyral binder and the charge transport layer of said drum has a polycarbonate binder.
12. The method according to claim 5 which comprises the additional step of re-applying a new charge transport layer to the treated photosensitive drum.
13. The method according to claim 2 when the ultrasonic energy applied has a frequency of from about 35 to about 45 kHz.
14. A method for selectively removing the charge transport layer from a photosensitive drum without damaging the charge generating layer on said drum, comprising the steps of:
immersing the drum in a solvent selected from dibasic esters, aromatic solvents, acetone, and mixtures thereof, said solvent being substantially free of water; and
applying ultrasonic energy to said drum while it is immersed in the solvent.
15. The method according to claim 14 wherein the ultrasonic energy is applied in a range of from about 300 to about 500 watts/ft 3 .
16. The method according to claim 15 wherein the ultrasonic energy applied has a frequency of from about 35 to about 45 kHz.
17. The method according to claim 16 carried out at a temperature of from about 25° C. to about 65° C.
18. The method according to claim 17 wherein the ultrasonic energy is applied for a period of no greater than about 30 minutes.
19. The method according to claim 18 wherein the ultrasonic energy is applied for a period of no greater than about 15 minutes.
20. The method according to claim 19 wherein the solvent comprises dibasic esters.
21. The method according to claim 20 wherein the solvent comprises dimethyl succinate.
22. The method according to claim 20 wherein the solvent is a mixture of dibasic esters comprising dimethyl succinate.
23. The method according to claim 20 wherein the ultrasonic energy is applied for from about 5 minutes to about 10 minutes.
24. The method according to claim 22 wherein the ultrasonic energy is applied for from about 5 minutes to about 10 minutes.
25. The method according to claim 19 wherein the solvent is selected from the group consisting of dimethyl succinate, acetone, toluene, xylene, and mixtures thereof.
26. The method according to claim 20 which comprises the additional step of re-applying a new charged transport layer to the treated photosensitive drum.
27. The method according to claim 25 wherein the charge generating layer of said drum has a polyvinylbutyral binder and the charge transport layer has a polycarbonate binder.