SUBSTRATE FOR PHOTOSENSITIVE DRUM

• US 20140295206A1
• Filed: 08/13/2012
• Published: 10/02/2014
• Est. Priority Date: 08/19/2011
• Status: Abandoned Application

• Current Assignee: Showa Denko KK
• Original Assignee: Showa Denko KK
• Inventors: Aoya, Shigeru, Oide, Masaaki
• Application Number:
  US14/238,879
• Publication Number:
  US 20140295206A1
• Time in Patent Office: Days
• US Class Current: 428/600
• CPC Class Codes: B21C 23/217 Tube extrusion presses B21C23/218 takes precedence
• CPC Class Codes: G03G 5/102 consisting of or comprising metals
• CPC Class Codes: Y10T 428/12389 having variation in thickness

Abstract

A substrate 41 for a photosensitive drum is formed from an uncut metal tube. In an observation visual field 52 in which an image forming surface 41aa of a surface 41a of the substrate 41 is observed in a visual field having an arbitrary size, a total occupancy area ratio of pits having an area ratio of 1 μm² or more with respect to the observation visual field area is 2% or more, and the average area per pit having an area of 1 μm² or more is greater than 8 μm².

Claims

1. A substrate for a photosensitive drum formed from an uncut metal tube,

wherein, in an observation visual field in which an image forming surface is observed in a visual field having an arbitrary size, a total occupancy area ratio of pits having an area of 1 μ

m² or more with respect to an area of the observation visual field is 2% or more, and an average area per pit having an area of 1 μ

m² or more is greater than 8 μ

m².

2. The substrate for a photosensitive drum as recited in claim 1, wherein, in the observation visual field,

the total occupancy area ratio of pits having an area of 1 μ

m² or more with respect to the area of the observation visual field is 15% or less,

the average area per pit having an area of 1 μ

m² or more is 20 μ

m² or less, and

no large pits having an area of 300 μ

m² or more exist.

3. The substrate for a photosensitive drum as recited in claim 1, wherein the substrate is made of aluminum.

4. A production method of the substrate for a photosensitive drum as recited in claim 1, the method comprising:

a drawing process step of obtaining an uncut metal tube by subjecting an extruded metal tube to a drawing process using a drawing device equipped with a drawing die for processing an outer surface of the extruded metal tube and a drawing plug for processing an inner surface of the extruded metal tube,

wherein the drawing die includes

a first curved surface portion from which the extruded metal tube separates while being subjected to a diameter reducing process,

a die bearing portion arranged radially inward of and downstream of an extruded metal tube separating position on the first curved surface portion, and

a guiding portion having a second curved surface portion smoothly continued to an upstream end of the die bearing portion, the guiding portion being configured to guide the extruded metal tube to the die bearing portion while subjecting the extruded metal tube to a diameter reducing process by coming into re-contact with the extruded metal tube separated from the first curved surface portion, and

wherein the drawing plug is equipped with a plug bearing portion shorter than a length of the die bearing portion.