Aluminum pipe having excellent surface quality, method and apparatus for manufacturing the aluminum pipe, and photosensitive drum base body

Abstract

In a manufacturing method in which an aluminum bullet is extruded to obtain an extruded raw pipe 4 and then the extruded raw pipe 4 is subjected to a drawn process, the aluminum extruded raw pipe 4 is cut at a position within 10 m from a discharge position M of an extruding die to obtain an aluminum extruded raw pipe 4 with a length of 10 m or shorter, and the extruded raw pipe 4 is subjected to a drawing process. With this, an aluminum pipe excellent in surface quality having no surface defect such as white peeling can be manufactured at high manufacturing efficiency.

1 . A method of manufacturing an aluminum pipe excellent in surface quality by extruding an aluminum billet to obtain an aluminum extruded raw pipe and then drawing the aluminum extruded raw pipe, 
 wherein the extruded aluminum extruded raw pipe is cut at a position within 10 m from a discharge position of an extruding die to obtain an aluminum extruded raw pipe with a length of 10 m or shorter, and the cut aluminum extruded raw pipe is subjected to a drawing process.    
   
   
       2 . A method of manufacturing an aluminum pipe excellent in surface quality, comprising; 
 an extruding step for extruding an aluminum billet to obtain an aluminum extruded raw pipe;    a cutting step for cutting the extruded aluminum extruded raw pipe at a position within 10 m from a discharge position of an extruding die to obtain an aluminum extruded raw pipe with a length of 10 m or shorter; and    a drawing step for drawing the cut aluminum extruded raw pipe to obtain an aluminum pipe.    
   
   
       3 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the extruded aluminum extruded raw pipe is cut at the position within 10 m from the discharge position of the extruding die to thereby obtain an aluminum extruded raw pipe with a length of 1 to 6 m.  
   
   
       4 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the extruded aluminum extruded raw pipe is cut at the position within 7 m from the discharge position of the extruding die to thereby obtain an aluminum extruded raw pipe with a length of 2 to 5 m.  
   
   
       5 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in any one of  claims 1  to  4 , wherein the extruded aluminum extruded raw pipe is conveyed towards an extruding direction while supporting the raw pipe with a supporting roller having a synthetic fiber felt circumferentially attached on an external peripheral surface of a roller core portion.  
   
   
       6 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 5 , wherein a main fiber constituting the felt is an aramid fiber.  
   
   
       7 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein, as the aluminum billet, a billet consisting of Mn: 1.1 to 1.6 mass %, Si: 0.7 mass % or less, Fe: 0.8 mass % or less, Cu: 0.04 to 0.21 mass %, Zn: 0.11 mass % or less, and the balance being aluminum and inevitable impurities is used.  
   
   
       8 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the extruding is performed using an extruding die in which an extrusion directional length L of a die bearing portion defining an external surface of the aluminum extruded raw pipe is 5 mm or shorter and a relationship between a peripheral directional center line average roughness Ra(Y) of the bearing portion and an extrusion directional center line average roughness Ra(X) of the bearing portion is set to Ra(Y)<Ra(X).  
   
   
       9 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the extruding is performed using an extruding die in which a bearing portion is formed of superhard material and surface roughness of the bearing portion is adjusted to 5 to 30 μm in Ry (maximum height).  
   
   
       10 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein peripheral directional surface roughness of the aluminum extruded raw pipe obtained by the cutting is 0.5 to 10 μm in Ry (maximum height).  
   
   
       11 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein, in drawing the aluminum extruded raw pipe after the cutting by pulling the extruded raw pipe between a drawing die and a drawing plug, 
 the drawing is performed while supplying lubricating oil of 200 cst or less in viscosity between the drawing die and the extruded raw pipe so that an external diameter reduction rate from the extruded raw pipe to an aluminum pipe is 30% or less and a cross-sectional area reduction rate is 5% or more.    
   
   
       12 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein, in drawing the aluminum extruded raw pipe after the cutting by pulling the extruded raw pipe between a drawing die and a drawing plug, 
 as a rod for supporting the drawing plug, a rod provided with one or a plurality of cores coming into contact with an internal peripheral surface of the extruded raw pipe along an entire length of the extruded raw pipe is used.    
   
   
       13 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 12 , wherein a groove parallel to an axis is formed on an external peripheral surface of the core.  
   
   
       14 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein, in drawing the aluminum extruded raw pipe after the cutting by pulling the extruded raw pipe between a drawing die and a drawing plug, 
 as the drawing die, a die in which an approach angle is set so as to fall within a range of 10 to 40° and a bearing length is set so as to fall within a range of 8 to 25 mm is used, and    as the drawing plug, a plug in which an approach angle is set so as to fall within a range of 6 to 10° and a bearing length is set so as to fall within a range of 1.5 to 3 mm is used.    
   
   
       15 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the drawing is performed by drawing the aluminum extruded raw pipe having a crystal grain whose average length in a drawing direction is 60 μm or more on a surface of the aluminum extruded raw pipe obtained by the cutting so that the average length of the crystal grain in the drawing direction becomes 1.3 times or more, thereby obtaining an aluminum pipe having a crystal grain whose average length in the drawing direction exceeds 300 μm.  
   
   
       16 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein, after cutting off a chucked portion of the aluminum pipe obtained by the drawing by a press cutting method, straightening of the aluminum pipe is performed using a roll straightening machine.  
   
   
       17 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the aluminum pipe obtained by the drawing is washed using a solvent with a KB (kauri-butanol) value of 20 or more within three days after the drawing.  
   
   
       18 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the aluminum pipe obtained by the drawing is subjected to ultrasonic cleaning by setting a relationship between a frequency f (kHz) of a ultrasonic wave of an ultrasonic wave oscillator and an ultrasonic cleaning time T (minute) to f×T≦120 (kHz·min).  
   
   
       19 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 18 , wherein the ultrasonic cleaning is performed by setting a relationship between an output P (W) of the ultrasonic wave oscillator and an ultrasonic oscillation area S (cm 2 ) to 0.1≦P/S≦1.0 (W/cm 2 ).  
   
   
       20 . The method of manufacturing an aluminum pipe excellent in surface quality as recited in  claim 1  or  2 , wherein the aluminum pipe is an aluminum pipe for photosensitive drums.  
   
   
       21 . An aluminum pipe manufactured by the manufacturing method as recited in any one of  claims 1  to  19 .  
   
   
       22 . A photosensitive drum substrate made of an aluminum pipe manufactured by the manufacturing method as recited in any one of  claims 1  to  19 .  
   
   
       23 . An apparatus for manufacturing an aluminum pipe, comprising: 
 an extruding machine; and    a cutting machine disposed at an extruding direction front position of the extruding machine and configured to execute cutting of the aluminum extruded raw pipe which is being extruded from the extruding machine while moving in synchronization with a traveling speed of the aluminum extruded raw pipe,    wherein the cutting of the aluminum extruded raw pipe with the cutting machine is executed at a position within 10 m from a discharge position of the extruding die of the extruding machine.    
   
   
       24 . The apparatus for manufacturing an aluminum pipe as recited in  claim 23 , wherein a supporting roller with a synthetic fiber felt circumferentially attached on an external peripheral surface of a roller core portion is disposed between the extruding machine and the cutting machine.  
   
   
       25 . The apparatus for manufacturing an aluminum pipe as recited in  claim 24 , wherein a main fiber constituting the felt is an aramid fiber.  
   
   
       26 . The apparatus for manufacturing an aluminum pipe as recited in any one of  claims 23  to  25 , further comprising a control apparatus for controlling execution of an cutting operation of the cutting machine based on information of the traveling speed of the aluminum extruded raw pipe obtained from a speed sensor.  
   
   
       27 . The apparatus for manufacturing an aluminum pipe as recited in any one of  claims 23  to  25 , wherein the cutting of the aluminum extruded raw pipe with the cutting machine is executed at a position within 7 m from a discharge position of the extruding die of the extruding machine.  
   
   
       28 . An aluminum drawn pipe having substantially no fine thready surface defect extending approximately in a drawing direction on a surface of the aluminum drawn pipe.  
   
   
       29 . A photosensitive drum substrate made of an aluminum drawn pipe having substantially no fine thready surface defect extending approximately in a drawing direction on a surface of the aluminum drawn pipe.  
   
   
       30 . A photosensitive drum with a photosensitive layer formed on an external peripheral surface of the photosensitive drum substrate as recited in  claim 22  or  29 .  
   
   
       31 . An electrophotographic device constituted by the photosensitive drum as recited in  claim 30.