Canon Kabushiki Kaisha

Jfe Steel Corporation

Jfe Civil Engineering & Construction Corporation

Wataru Kitamura

Mai Murakami

Ryoichi Tokimitsu

Kumiko Takizawa

Yuka Ishiduka

Tsuyoshi Shimada

Takeshi Murakami

Kenichi Kaku

Ikuyo Kuroiwa

Kan Tanabe

Eileen Takeuchi

Hideki Ogawa

Kenichi Ikari

Harunobu Ogaki

Atsushi Okuda

Hidetoshi Hirano

Haruhiko Mitsuda

Kimihiro Yoshimura

Kazumichi Sugiyama

Masaki Nonaka

Hideaki Nagasaka

Daisuke Kawaguchi

Koji Takahashi

Yuki Yamamoto

Akira Yoshida

Osamu Tamura

Takanori Ueno

Yoshihisa Saito

Tatsuya Ikezue

Hideki Anayama

Yohei Miyauchi

Takakazu Tanaka

Yasuhiro Kawai

Hirotoshi Uesugi

Naoaki Ichihashi

Tomohiro Kinoshita

Kazuaki Miyagawa

Takumi Ishii

Provided is an electrophotographic photosensitive member in which the generation of a positive ghost image is suppressed under a low-temperature and low-humidity environment, and the occurrence of cracking is suppressed under a high-temperature and high-humidity environment. Also provided are a process cartridge mounted with the electrophotographic photosensitive member, and an electrophotographic apparatus including the process cartridge. The electrophotographic photosensitive member of the present disclosure is characterized in that an undercoat layer contains aluminum oxide particles and titanium oxide particles at a specific mass ratio.

Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

An electrophotographic photosensitive member includes a support, an undercoat layer, a photosensitive layer, and a surface layer, the undercoat layer containing a binder resin and strontium titanate particles, the surface layer being a cured film of a composition containing at least one compound selected from a guanamine compound and a melamine compound, and a charge transport material having at least one substituent selected from &#x2014;OH, &#x2014;OCH, &#x2014;NH, &#x2014;SH, and &#x2014;COOH.

Provided is an electrophotographic photosensitive member that can suppress the generation of both an interference fringe and a streaky uneven part in a circumferential direction on an image. The generation of the interference fringe and the generation of the streaky uneven part in the circumferential direction on the image are suppressed by defining a length of a line-shaped groove of a support in a circumferential direction, and defining roughness parameters of a support in an axial direction.

Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus

There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus in which residual potential is suppressed and a ghost image is prevented from being generated in a low-humidity environment in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member including: an undercoat layer containing a strontium titanate particle having a maximum peak at a position of 2&#x3b8;=32.20&#xb1;0.20 (&#x3b8; represents a Bragg angle) in a CuK&#x3b1; characteristic X-ray diffraction pattern and a half-value width of the maximum peak of 0.10 deg or more and 0.50 deg or less, and a titanium oxide particle; and a photosensitive layer containing a polyvinyl butyral resin, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.

There is provided an electrophotographic photosensitive member in which the variation in potential during repeated use is reduced. The electrophotographic photosensitive member is the electrophotographic photosensitive member of which an undercoat layer comprises a urethane resin and titanium oxide particles whose primary particle and secondary particle diameters are defined.

There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus that are excellent in charging properties and can suppress residual potential in the case where a strontium titanate particle is used as a metal oxide particle in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member in which an undercoat layer contains a strontium titanate particle having a maximum peak at a position of 2&#x3b8;=32.20&#xb1;0.20 (&#x3b8; represents a Bragg angle) in a CuK&#x3b1; characteristic X-ray diffraction pattern, the maximum peak having a half-value width of 0.10 deg or more and 0.50 deg or less, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.

In the electrophotographic photosensitive member of the present invention, a plurality of convex portions having a longest diameter Lin the generatrix direction of the electrophotographic photosensitive member of 30 &#x3bc;m or more arid a height Hof 1 &#x3bc;m or more are formed on the surface of the electrophotographic photosensitive member, a plurality of convex portions corresponding to the convex portions formed on the surface of the surface layer are formed at the interface between the surface layer and a layer immediately below the surface layer, and the rate of fitting of the convex portions formed on the surface of the surface layer to the convex portions formed at the interface between the surface layer and the layer immediately below the surface layer is 20% or more and 200% or less.

The present invention provides an electrophotographic apparatus in which the deterioration of electrical properties in repetitive use is suppressed even in the case where an electrophotographic photosensitive member absorbs moisture under a high-temperature and high-humidity environment. An undercoat layer of the electrophotographic photosensitive member provided in the electrophotographic apparatus contains (&#x3b1;) a metal oxide particle, (&#x3b2;) a particular benzophenone compound and (&#x3b3;) a compound represented by the following formula (2). wherein Rto Reach independently represent a hydrogen atom, a hydroxy group, a halogen atom, an alkyl group, an alkoxy group or an amino group and Arepresents an alkenyl group having 2 or more and 4 or less carbon atoms.

Electrophotographic apparatus

In an electrophotographic photosensitive member, a circumferential surface has concave portions that are independent one another; each of the concave portions has an opening, a contour of the opening has an apex having an angle &#x3b1; of more than 0&#xb0; and 90&#xb0; or less on at least an upstream side of a rotational direction of the electrophotographic photosensitive member, and has a largest width in an axial direction of the electrophotographic photosensitive member of 20 &#x3bc;m or more and 80 &#x3bc;m or less, a width of the contour in the axial direction of the electrophotographic photosensitive member decreasing from a portion having the largest width toward the apex, when viewing each of the concave portions in the axial direction, each of the concave portions has a depth that decreases from a deepest point of each of the concave portions toward the apex.

An undercoat layer of an electrophotographic photosensitive member contains a binder resin and conductive particles. Each of the conductive particles has a core particle coated with tin oxide doped with aluminum.

A pin joint type structural member, made of double steel pipe consisting of a main pipe and a stiffening pipe, restrains buckling so as to be stable under axial compressive force. A clearance between the stiffening pipeand the reinforcing member is determined so that a ratio (P/P) of the reinforcing member contact force with the stiffening pipe inner surface at the endof a counter-clevis side, to the reinforcing member contact force with the stiffening pipe inner surface at the endof the clevis side may be 0.40 to 0.65 when the reinforcing memberinclines to the main pipedue to the axial force acting on the main pipe. In addition, a length Lthat the stiffening pipeoverlaps with the reinforcing memberis at least 1.1 times as large as the reinforcing member outer diameter at the overlapping portion.

Pin joint type structural member made of double steel pipe for restraining buckling thereof

An electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus wherein a streak-like image defect otherwise occurring in output in a low printing mode performed under a H/H environment can be reduced are provided. A surface of the photosensitive member has a convex and concave portions continuously in a peripheral direction of the photosensitive member, and alternately in an axial direction of the photosensitive member, a width w of the concave portion is 30 to 100 &#x3bc;m, a depth d of the concave portion is 1 to 5 &#x3bc;m, the convex portion has a rising slope and a descending slope in the peripheral direction of the photosensitive member, and a distance from a starting point of the rising slope to an end point of the descending slope and a distance from a starting point of the descending slope to an end point of the rising slope are 300 &#x3bc;m or less.

The present invention provides an electrophotographic photosensitive member in which an undercoat layer contains a metal oxide particle, a particular benzophenone compound and a particular ketone compound, a process cartridge and an electrophotographic apparatus each including the electrophotographic photosensitive member and a process for producing the electrophotographic photosensitive member.

Electrophotographic photosensitive member, process cartridge, electrophotographic apparatus and process for producing electrophotographic photosensitive member

An electrophotographic photosensitive member includes a support, an undercoat layer which contains a metal oxide particle and is formed on the support, a charge generating layer formed on the undercoat layer, and a charge transporting layer formed on the charge generating layer. Either or both of the undercoat layer and the charge generating layer contain a compound represented by formula (1).

Electrophotographic photosensitive member, method for producing electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

An electrophotographic photosensitive member includes a surface layer with a hexagonal boron nitride dispersed therein. The hexagonal boron nitride has a graphitization index (GI) of at least 3.0 and less than 15.0.

Growing community of inventors

Abiko, Japan

Wataru Kitamura