Technology for High-Reliability, High-Durability Photoconductors
Ricoh has developed a technology for high-reliability, high-durability photoconductors that make possible reduced service costs for high-speed copiers for the commercial printing market and the corporate in-house printing market.
Photoconductor Quality for Demanding Commercial Use
In the commercial printing market and corporate in-house printing market, in recent years a shift to high-variety, small-lot printing has resulted in increased needs for color print on demand (POD), the capability to print at low cost the exact quantity of printed materials required as and when they are required. Thanks to a newly developed high-speed print engine that incorporates a photoconductor developed using this technology, the RICOH Pro C900 realizes higher definition, higher reliability and durability, and higher productivity as well as sharp reductions in size and weight in comparison with previous machines. This photoconductor plays an especially important role in the assurance of high reliability and durability.
This photoconductor was adopted for a highly efficient production printer, RICOH Pro C901S/901、Pro C751EX/C651EX.
The Structure of the Newly Developed Functionally Separated Photoconductor
As shown in Figure 1, the newly developed high-reliability, high-durability photoconductor has a structure consisting of functionally separated layers on top of a large-diameter (100mm) aluminum support. These layers are configured as described below in a high-sensitivity photoconductor suitable for high-speed machines.
(a) Charge generation layer (CGL)
(b) Charge transport layer (CTL)
(c) Intermediate layer (IL): Improves electrostatic stability by increasing voltage endurance and preventing local leaks.
(d) Overcoat layer (OL): Combines the required electrical characteristics and abrasion resistance by means of the adoption of a new material developed in-house on the basis of materials technologies nurtured over many years.
Through a combination of these functionally separated layers, the newly developed photoconductor realizes the high-reliability and high-durability required for commercial use by achieving balance between mechanical abrasion resistance and electrical stability.
An Independently Developed Material Combining Electrical Characteristic Stability and Durability
The application of an overcoat to increase reliability is a commonplace technique in widespread use. However, the simple application of an overcoat to copier photoconductors would obstruct electrical charge movement, an electrical characteristic that is a basic characteristic of photoconductors, which would result in problems such as image density deterioration. Consequently, Ricoh developed in-house a new material that offers an increase in durability with no loss of electrical characteristics. By using this material in an overcoat, Ricoh has realized highly reliable photoconductors that combine greater durability with electrical characteristic stability.
This has made it possible to ensure stable copier operation and greatly reduce downtime and service costs required to respond to mechanical failure.