Special Issue; Products for Industrial Machinery - NTN

NTN TECHNICAL REVIEW No.742006
Technical Article
Technical Trends in Bearings for Office Equipment
Chikara KATAGIRI
Recently, the demand for digital color PPC's (Plain Paper
Copiers) and MFP's (Multi Function Printers) has been
increasing alongside personal computers, digital cameras and
the internet. During this time, NTN has been aggressively
working to develop technologies and products for this ever
increasing digital media market. This report discusses the
required function of photosensitive drums and fuser rollers for
the latest PPC's and MFP's, as well as bearing technologies
for these applications.
1. Introduction
Electrophotography began as a monochromatic
analog technology. Then, in 1983, Carlson (USA)
proposed color xerography, and in the 1990’s, digital
electrophotography became a technology that was
more commonly used. As more and more people have
begun using personal computers and the Internet,
electrophotographic equipment, including digital plain
paper copiers (PPC) and laser beam printers (LBP)
have become increasingly used as imaging devices
for diverse applications worldwide.
The requirements for bearings used in digital
copying machines and printers have become more
demanding. This paper describes the most recent
requirements for these bearings and the technologies
used to satisfy these requirements.
2. Structure of Color Copying
Machines and Color LBPs
The structure of a typical color copying machine or
color LBP is illustrated schematically in Fig. 1. Many
rolling bearings are used in color copying machines
and color LBPs. Recently, thin deep groove ball
bearings, such as those shown in Photo 1, have been
used more frequently in photosensitive sections and
fusing sections of these devices. Featuring smaller
cross-sectional areas, thin deep groove ball bearings
contribute to the compact design of mechanisms in
color copying machines and color LBPs and also help
provide extra space around the bearings.
Basic process of color copying machines and
color LBPs
1) Image exposure: The image being copied or
printed is formed as a latent image on the
photosensitive drum.
2) Developing: The toner is allowed to be attracted to
the latent image on the photosensitive drum to
make the image visible.
3) Transfer: The toner powder on the photosensitive
drum is transferred to a sheet of copy paper.
4) Fusing (fixing): The toner powder is fixed to the
copy paper by heat and pressure.
Industrial Engineering Dept. Industrial Sales headquarters
-62-