High-Reliability Cleaning Blade
The cleaning process of xerography involves removing such substances as corona products adhered to the surface of the photoreceptor after charging and toner or paper fibers remaining on the surface of the photoreceptor after the transfer process. The main component used in the cleaning process is the rubber blade, which scrapes off residual toner and other target matter by coming into contact with the surface of the rotating photoreceptor (Fig.1).
Deterioration of the cleaning blade's performance causes target matter to be left on the surface of the photoreceptor, and this in turn causes the performance of each step of the xerographic process to be impaired. The reasons for this deterioration in performance include wear or localized chipping of the blade edge, as well as diminished scraping ability due to permanent deformationNote1 of the blade rubber. These result in poor cleaning, causing colored or white streaks to appear on the output.
Fuji Xerox therefore developed a high-reliability cleaning blade that is able to maintain cleaning performance over the long term, enabling the provision of stable image quality.
In general, in order to prevent rubber from wearing, the hardness of the rubber is increased. However, high-hardness rubber is more prone to chipping and deformation.
In order to resolve these issues, Fuji Xerox designed a new cleaning blade by making the following changes from the conventional rubber blade, as shown in Fig. 2:
- The hardness of the rubber has been increased to improve its resistance to wear.
- The breaking elongation of the rubber has been increased so that stress is dispersed by local elongation when foreign material impacts the blade edge, thus improving its resistance to chipping.
In addition, we designed the blade with a two-layer configuration to solve the issue of the high-hardness rubber being prone to deformation. This two-layer cleaning blade is equipped with a back layer which minimizes permanent deformation (Fig. 3) in addition to the cleaning layer. As a result, the service life of the new cleaning blade has been prolonged to twice as long as that of the conventional blade (Fig. 4). Depending on use conditions, the two-layer configuration can cause an increased occurrence of blade noiseNote2. However, through computer simulation, it was revealed that the rebound resilience of the back layer has a great effect on the occurrence of blade noise, and we thereby designed a back layer with low rebound resilience. Thus, by developing a two-layered cleaning blade consisting of a high-hardness rubber cleaning layer with high breaking elongation and a back layer with small permanent elongation and low rebound resilience, we succeeded in creating a high-reliability cleaning blade that is resistant to wear and chipping while preventing the occurrence of permanent deformation and blade noise.
This new cleaning blade is incorporated into products which require a high degree of reliability.
- Note1 Plastic deformation caused by prolonged contact of the warped rubber blade with the photoreceptor
- Note2 Rubbing noise occurring when the photoreceptor rotates while in contact with the cleaning blade