Electrophotographic photoreceptor, process cartridge, and image forming apparatus
An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer disposed on the conductive substrate. An outermost surface layer of the electrophotographic photoreceptor contains a fluorine-containing resin particle and a fluorine-based graft polymer having a fluorinated alkyl group. A ratio of an amount of a fluorine-based graft polymer separated from the fluorine-containing resin particle to a total amount of the fluorine-based graft polymer in the outermost surface layer is 15% or less.
1. An electrophotographic photoreceptor comprising:
a conductive substrate; and
a photosensitive layer disposed on the conductive substrate, wherein
an outermost surface layer of the electrophotographic photoreceptor contains a fluorine-containing resin particle and a fluorine-based graft polymer having a fluorinated alkyl group, and
a ratio of an amount of a fluorine-based graft polymer separated from the fluorine-containing resin particle to a total amount of the fluorine-based graft polymer in the outermost surface layer is 15% by mass or less,
wherein the fluorine-based graft polymer has a weight-average molecular weight of 116,000 or more and 200,000 or less.
2. The electrophotographic photoreceptor according to claim 1 , wherein
the fluorine-based graft polymer includes a structural unit A having a fluorinated alkyl group having 2 to 8 carbon atoms and a structural unit B having a graft chain, and
in an infrared absorption spectrum of the fluorine-based graft polymer, a ratio (S 2 /S 1 ) of a peak area S 2 in a wavenumber range of from 1,020 cm −1 to 1,308 cm −1 to a peak area S 1 in a wavenumber range of from 1,673 cm −1 to 1,779 cm −1 is 2.7 or more and 4.8 or less.
3. The electrophotographic photoreceptor according to claim 2 , wherein, in the infrared absorption spectrum of the fluorine-based graft polymer, the ratio (S 2 /S 1 ) of the peak area S 2 in the wavenumber range of from 1,020 cm −1 to 1,308 cm −1 to the peak area S 1 in the wavenumber range of from 1,673 cm −1 to 1,779 cm −1 is 2.9 or more and 3.9 or less.
4. The electrophotographic photoreceptor according to claim 3 , wherein the fluorine-based graft polymer is a binary copolymer constituted by a structural unit represented by general formula (FA) and a structural unit represented by general formula (FB),
in the general formulae (FA) and (FB),
R F1 , R F2 , R F3 , and R F4 each independently represent a hydrogen atom or an alkyl group;
X F1 represents an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH—, or a single bond;
Y F1 represents an alkylene chain, a halogen-substituted alkylene chain, —(C fx H 2fx-1 (OH))—, or a single bond;
Q F1 represents —O— or —NH—;
fl and fin each represent a content by mass of a structural unit enclosed in parentheses relative to the total structural units of the fluorine-based graft polymer;
fn is a number of structural units enclosed in parentheses and represents an integer of 1 or more;
fp, fq, fr, and fs each independently represent an integer of 0 or 1 or more;
ft represents an integer of 1 or more and 7 or less; and
fx represents an integer of 1 or more.
5. The electrophotographic photoreceptor according to claim 3 , wherein a content of the fluorine-based graft polymer is 1% by mass or more and 10% by mass or less relative to the fluorine-containing resin particle.
6. The electrophotographic photoreceptor according to claim 3 , wherein
the outermost surface layer contains a dispersant-carrying particle formed of the fluorine-containing resin particle having a surface to which the fluorine-based graft polymer adheres, and
a content of perfluorooctanoic acid in the dispersant-carrying particle is 0 ppb or more and 25 ppb or less relative to a total mass of the fluorine-containing resin particle.
7. The electrophotographic photoreceptor according to claim 2 , wherein the fluorine-based graft polymer is a binary copolymer constituted by a structural unit represented by general formula (FA) and a structural unit represented by general formula (FB),
in the general formulae (FA) and (FB),
R F1 , R F2 , R F3 , and R F4 each independently represent a hydrogen atom or an alkyl group;
X F1 represents an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH—, or a single bond;
Y F1 represents an alkylene chain, a halogen-substituted alkylene chain, —(C fx H 2fx-1 (OH))—, or a single bond;
Q F1 represents —O— or —NH—;
fl and fin each represent a content by mass of a structural unit enclosed in parentheses relative to the total structural units of the fluorine-based graft polymer;
fn is a number of structural units enclosed in parentheses and represents an integer of 1 or more;
fp, fq, fr, and fs each independently represent an integer of 0 or 1 or more;
ft represents an integer of 1 or more and 7 or less; and
fx represents an integer of 1 or more.
8. The electrophotographic photoreceptor according to claim 2 , wherein a content of the fluorine-based graft polymer is 1% by mass or more and 10% by mass or less relative to the fluorine-containing resin particle.
9. The electrophotographic photoreceptor according to claim 2 , wherein
the outermost surface layer contains a dispersant-carrying particle formed of the fluorine-containing resin particle having a surface to which the fluorine-based graft polymer adheres, and
a content of perfluorooctanoic acid in the dispersant-carrying particle is 0 ppb or more and 25 ppb or less relative to a total mass of the fluorine-containing resin particle.
10. The electrophotographic photoreceptor according to claim 1 , wherein the fluorine-based graft polymer is a binary copolymer constituted by a structural unit represented by general formula (FA) and a structural unit represented by general formula (FB),
in the general formulae (FA) and (FB),
R F1 , R F2 , R F3 , and R F4 each independently represent a hydrogen atom or an alkyl group;
X F1 represents an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH—, or a single bond;
Y F1 represents an alkylene chain, a halogen-substituted alkylene chain, —(C fx H 2fx-1 (OH))—, or a single bond;
Q F1 represents —O— or —NH—;
fl and fin each represent a content by mass of a structural unit enclosed in parentheses relative to the total structural units of the fluorine-based graft polymer;
fn is a number of structural units enclosed in parentheses and represents an integer of 1 or more;
fp, fq, fr, and fs each independently represent an integer of 0 or 1 or more;
ft represents an integer of 1 or more and 7 or less; and
fx represents an integer of 1 or more.
11. The electrophotographic photoreceptor according to claim 1 , wherein a content of the fluorine-based graft polymer is 1% by mass or more and 10% by mass or less relative to the fluorine-containing resin particle.
12. The electrophotographic photoreceptor according to claim 1 , wherein
the outermost surface layer contains a dispersant-carrying particle formed of the fluorine-containing resin particle having a surface to which the fluorine-based graft polymer adheres, and
a content of perfluorooctanoic acid in the dispersant-carrying particle is 0 ppb or more and 25 ppb or less relative to a total mass of the fluorine-containing resin particle.
13. A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising:
the electrophotographic photoreceptor according to claim 1 .
14. An image forming apparatus comprising:
the electrophotographic photoreceptor according to claim 1 ;
a charging unit that charges a surface of the electrophotographic photoreceptor;
an electrostatic latent image forming unit that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;
a developing unit that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor by using a developer that contains a toner to form a toner image; and
a transfer unit that transfers the toner image onto a surface of a recording medium.