Image forming apparatus and process cartridge
An image forming apparatus includes an image holding member including a conductive substrate, a photosensitive layer, and a protection layer; a charging unit; an electrostatic image forming unit; a developing unit that includes an electrostatic image developer having a toner and develops the electrostatic image to form a toner image; a transfer unit that transfers the toner image onto a surface of a recording medium; a fixing unit that fixes the toner image; and a cleaning unit that includes a cleaning blade. The toner includes toner particles and silica particles having a number average particle size of 110 nm to 130 nm, a large-diameter-side number particle size distribution index (upper GSDp) of less than 1.080, and an average circularity of 0.94 to 0.98, wherein 80 number % or more of the silica particles have a circularity of 0.92 or more.
1. An image forming apparatus comprising:
an image holding member including
a conductive substrate,
a photosensitive layer disposed on the conductive substrate, and
a protection layer disposed on the photosensitive layer;
a charging unit that charges a surface of the image holding member;
an electrostatic image forming unit that forms an electrostatic image on the charged surface of the image holding member;
a developing unit that includes an electrostatic image developer having a toner and develops the electrostatic image formed on the surface of the image holding member with the electrostatic image developer to form a toner image;
a transfer unit that transfers the toner image onto a surface of a recording medium;
a fixing unit that fixes the toner image transferred on the surface of the recording medium; and
a cleaning unit that includes a cleaning blade that removes toner particles present on the surface of the image holding member,
the toner including
toner particles; and
silica particles having a number average particle size of 110 nm to 130 nm, a large-diameter-side number particle size distribution index (upper GSDp) of less than 1.080, and an average circularity of 0.94 to 0.98, wherein 80 number % or more of the silica particles have a circularity of 0.92 or more.
2. The image forming apparatus according to claim 1 ,
wherein the silica particles have a large-diameter-side number particle size distribution index (upper GSDp) of 1.075 or less.
3. The image forming apparatus according to claim 1 ,
wherein the silica particles have a small-diameter-side number particle size distribution index (lower GSDp) of 1.080 or less.
4. The image forming apparatus according to claim 1 ,
wherein the silica particles have an average circularity of 0.95 to 0.97.
5. The image forming apparatus according to claim 1 ,
wherein 85 number % or more of the silica particles have a circularity of 0.92 or more.
6. The image forming apparatus according to claim 1 ,
wherein the protection layer includes an acrylic resin.
7. The image forming apparatus according to claim 6 ,
wherein the acrylic resin has a charge transporting skeleton.
8. The image forming apparatus according to claim 7 ,
wherein the charge transporting skeleton includes a triarylamine skeleton.
9. The image forming apparatus according to claim 1 ,
wherein the toner particles include a styrene acrylic resin as a binder resin.
10. The image forming apparatus according to claim 1 ,
wherein the toner particles include a polyester resin as a binder resin.
11. A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising:
an image holding member including
a conductive substrate,
a photosensitive layer disposed on the conductive substrate, and
a protection layer disposed on the photosensitive layer;
a developing unit that includes an electrostatic image developer having a toner and develops an electrostatic latent image formed on a surface of the image holding member with the electrostatic image developer to form a toner image; and
a cleaning unit that includes a cleaning blade that removes toner particles present on the surface of the image holding member,
the toner including
toner particles; and
silica particles having a number average particle size of 110 nm to 130 nm, a large-diameter-side number particle size distribution index (upper GSDp) of less than 1.080, and an average circularity of 0.94 to 0.98, wherein 80 number % or more of the silica particles have a circularity of 0.92 or more.
12. The image forming apparatus according to claim 1 ,
wherein the large-diameter-side number particle size distribution index (upper GSDp) of the silica particles is 1.072 or less.
13. The image forming apparatus according to claim 1 ,
wherein the large-diameter-side number particle size distribution index (upper GSDp) of the silica particles is 1.065 or less.