US 7,496,324 B2
Lubricant applying unit and image forming apparatus
Kenji Sugiura, Yokohama (Japan); Takahiko Tokumasu, Atsugi (Japan); Daichi Yamaguchi, Hino (Japan); and Takuya Seshita, Yokohama (Japan)
Assigned to Ricoh Company, Ltd., Tokyo (Japan)
Filed on Oct. 27, 2005, as Appl. No. 11/259,031.
Claims priority of application No. 2004-312097 (JP), filed on Oct. 27, 2004; application No. 2005-040420 (JP), filed on Feb. 17, 2005; and application No. 2005-159781 (JP), filed on May 31, 2005.
Prior Publication US 2006/0133872 A1, Jun. 22, 2006
Int. Cl. G03G 21/00 (2006.01)
U.S. Cl. 399—346  [399/350] 21 Claims
OG exemplary drawing
 
1. A lubricant applying unit for use in an image forming apparatus having a photosensitive member and a charge device, comprising:
a lubricant applying member configured to apply lubricant on a surface of the photosensitive member; and
a leveling member configured to level off the lubricant applied on the surface of the photosensitive member,
wherein the charge device is configured to apply a bias voltage, having direct current voltage and alternating current voltage superimposed to the direct current voltage, to the photosensitive member, and a metal element percentage EP(%) of the lubricant on the photosensitive member, measured by X-ray photoelectron spectroscopy after applying the lubricant, satisfies a relationship of
EP≧1.52×10−4×(Vpp−2×Vth)×(f/v),
wherein Vpp is a voltage amplitude of an alternating current component applied to the charge device, f is frequency (Hz) of the alternating current component applied to the charge device, v is a moving speed (mm/see) of the surface of the photosensitive member, and Vth is a discharge initiation voltage defined by a formula of
Vth=312+6.2×(d/εopc+Gpp/εair)+√(7737.6×d/ε)
wherein d(μm) is a layer thickness of a to-be-charged portion of the photosensitive member, Gpp is a minimum distance (μm) between a surface of the charge device and a surface of the photosensitive member, εopc is a relative dielectric constant of the photosensitive member, and εair is a relative dielectric constant of space between the charge device and the photosensitive member.