Titanylphthalocyanine crystal and method of producing the titanylphthalocyanine crystal, and electrophotographic photoreceptor, method, apparatus and process cartridge using the titanylphthalocyanine crystal

Abstract

A titanylphthalocyanine crystal having an X-ray diffraction spectrum having plural diffraction peaks and a primary particle diameter not greater than 0.2 μm, wherein a maximum diffraction peak is observed at a Bragg (2 θ) angle of 27.2±0.2°; main peaks are observed at 9.4°, 9.6° and 24.0°; and a minimum diffraction peak is observed at 7.3°; and preferably no diffraction peak is observed at an angle greater than 7.3° and less than 9.4° when a specific X-ray of CuKα having a wavelength of 1.542 Å irradiates the titanylphthalocyanine crystal.

1 - 19 . (canceled) 
   
   
       20 : A crystalline pigment comprising titanylphthalocyanine and tetra hydrofuran or toluene;
 wherein said crystalline pigment has a CuKα 1.542 Å X-ray diffraction spectrum comprising plural diffraction peaks and a primary particle diameter not greater than 0.2 μm,   wherein a maximum diffraction peak is observed at a Bragg (2θ) angle of 27.2°; main peaks are observed at 9.4°, 9.6° and 24.0°; and a minimum diffraction peak is observed at 7.3°; and no diffraction peak is observed at an angle greater than 7.3° and less than 9.4°,   wherein said angles may vary by ±0.2° and the minimum interval where no peak is observed between required peaks at 7.3 and 9.4 is 2.0 degrees absolute or more, and   wherein no diffraction peak is observed at 26.3°.   
   
   
       21 : An electrophotographic photoreceptor comprising:
 an electroconductive substrate;   a charge generation layer located overlying the electroconductive substrate and comprising the crystalline pigment according to  claim 20 ; and   a charge transport layer located overlying the charge generation layer.   
   
   
       22 : The electrophotographic photoreceptor of  claim 21 , wherein the charge transport layer comprises a charge transport polymer material. 
   
   
       23 : The electrophotographic photoreceptor of  claim 21 , further comprising a protection layer located overlying the charge transport layer. 
   
   
       24 : The electrophotographic photoreceptor of  claim 22 , wherein the protection layer comprises at least one of an inorganic pigment and a metal oxide, which have a resistivity not less than 10 10  Ω·cm. 
   
   
       25 : The electrophotographic photoreceptor of  claim 24 , comprising a metal oxide selected from the group consisting of alumina, titanium oxide and silica. 
   
   
       26 : The electrophotographic photoreceptor of  claim 23 , wherein the protection layer comprises a charge transport polymer material. 
   
   
       27 : The electrophotographic photoreceptor of  claim 21 , wherein an oxide film is formed on the substrate by anodizing. 
   
   
       28 : An image forming method comprising;
 charging the electrophotographic photoreceptor according to  claim 21 ;   irradiating the electrophotographic photoreceptor with imagewise light to form an electrostatic latent image thereon;   developing the electrostatic latent image with a developer comprising a toner to form a toner image thereon; and   transferring the toner image onto a transfer sheet.   
   
   
       29 : An image forming apparatus comprising;
 at least one image forming unit comprising;   the electrophotographic photoreceptor according to  claim 21 ;   a charger configured to charge the electrophotographic photoreceptor;   an irradiator configured to irradiate the electrophotographic photoreceptor with imagewise light to form an electrostatic latent image thereon;   an image developer configured to develop the electrostatic latent image with a developer comprising a toner to form a toner image thereon; and   a transferer configured to transfer the toner image onto a transfer sheet.   
   
   
       30 : The image forming apparatus of  claim 29 , comprising plural image forming units. 
   
   
       31 : The image forming apparatus of  claim 29 , wherein the charger is contacted or located close to the electrophotographic photoreceptor. 
   
   
       32 : The image forming apparatus of  claim 31 , wherein the charger is located close to the electrophotographic photoreceptor and a gap between the charger and the electrophotographic photoreceptor is not greater than 200 μm. 
   
   
       33 : The image forming apparatus of  claim 29 , wherein the charger applies a DC voltage overlapped with an AC voltage to the electrophotographic photoreceptor. 
   
   
       34 : A process cartridge for an image forming apparatus, comprising;
 the electrophotographic photoreceptor according to  claim 21 ; and at least one of:   a charger configured to charge the electrophotographic photoreceptor;   an irradiator configured to irradiate the electrophotographic photoreceptor with imagewise light to form an electrostatic latent image thereon;   an image developer configured to develop the electrostatic latent image with a developer comprising a toner to form a toner image thereon;   a transferer configured to transfer the toner image onto a transfer sheet;   a cleaner configured to clean the photoreceptor after the toner image is transferred into the transfer sheet; and   a discharger configured to discharge charges remaining on the photoreceptor after the toner image is transferred into the transfer sheet.   
   
   
       35 : A method of producing the crystalline pigment of  claim 20  comprising:
 subjecting a titanylphthalocyanine, which is either amorphous or low-crystalline, and which has a maximum CuKα 1.542 Å diffraction peak having a half width not less than 1° at a Bragg (2 θ) angle of from 7.0 to 7.5°±0.2° and an average primary particle diameter not greater than 0.1 μm, to crystal conversion with an organic solvent in the present of water; and   separating the titanylphthalocyanine from the organic solvent before the titanylphthalocyanine crystal grows to a size where the average primary particle diameter is greater than 0.2 μm;   wherein the organic solvent is selected from the group consisting of tetra hydrofuran, toluene, and dichloromethane.   
   
   
       36 : The crystalline pigment of  claim 20 , wherein the pigment comprises tetra hydrofuran. 
   
   
       37 : The crystalline pigment of  claim 20 , wherein the pigment comprises toluene.