Toner, and image forming method and process cartridge using the toner
A toner is provided including toner particles A having a circularity of greater than 0.93 and not greater than 1.00 and toner particles B having a circularity of from 0.85 to 0.93, wherein the following relationships are satisfied: 70≦R A ≦95, 5≦R B ≦30, 0.014≦SD≦0.025, and 0.940≦ED≦0.950, wherein R A (% by number) represents a ratio of a number of the toner particles A to a total number of toner particles included in the toner, R B (% by number) represents a ratio of a number of the toner particles B to the total number of toner particles included in the toner, SD represents a standard deviation of circularity of the toner particles A, and ED represents an average envelope degree of the toner particles B.
1. A toner, comprising:
toner particles A having a circularity of greater than 0.93 and not greater than 1.00; and
toner particles B having a circularity of from 0.85 to 0.93,
wherein the following relationships are satisfied:
70 ≦R A ≦95
5 ≦R B ≦30
0.014 ≦SD≦ 0.025
0.940 ≦ED≦ 0.950
wherein R A (% by number) represents a ratio of a number of the toner particles A to a total number of toner particles included in the toner, R B (% by number) represents a ratio of a number of the toner particles B to the total number of toner particles included in the toner, SD represents a standard deviation of circularity of the toner particles A, and ED represents an average envelope degree of the toner particles B, and
wherein the toner has a ½ method melting temperature from 100 to 115° C., and
wherein both toner particles A and B comprise a polyol resin.
2. The toner according to claim 1 , further comprising silica particles having a number average primary particle diameter (R) of from 80 to 200 nm.
3. The toner according to claim 2 , wherein the silica particles have a shape factor SF-1 of from 100 to 130 and a shape factor SF-2 of from 100 to 125, and the following relationship is satisfied:
R/ 4 ≦σ≦R
wherein R represents a number average primary particle diameter of the silica particles and σ represents a standard deviation of particle diameter distribution of the silica particles.
4. An image forming method, comprising:
forming an electrostatic latent image on an electrostatic latent image hearing member;
developing the electrostatic latent image with the toner according to claim 1 to form a toner image;
transferring the toner image onto a recording medium; and
fixing the toner image on the recording medium by a non-contact fixing means.
5. An image forming method according to claim 4 , wherein the toner further comprises silica particles having a number average primary particle diameter (R) of from 80 to 200 nm.
6. An image forming method according to claim 5 , wherein the silica particles have a shape factor SF-1 of from 100 to 130 and a shape factor SF-2 of from 100 to 125, and the following relationship is satisfied:
R/ 4 ≦σ≦R
wherein R represents a number average primary particle diameter of the silica particles and σ represents a standard deviation of particle diameter distribution of the silica particles.
7. A process cartridge detachably attachable to an image forming apparatus, comprising:
an electrostatic latent image bearing member configured to bear an electrostatic latent image; and
a development device which includes the toner according to claim 1 and configured to develop the electrostatic latent image with the toner.
8. A process cartridge according to claim 7 , wherein the toner further comprises silica particles having a number average primary particle diameter (R) of from 80 to 200 nm.
9. A process cartridge according to claim 8 , wherein the silica particles have a shape factor SF-1 of from 100 to 130 and a shape factor SF-2 of from 100 to 125, and the following relationship is satisfied:
R/ 4 ≦σ≦R
wherein R represents a number average primary particle diameter of the silica particles and σ represents a standard deviation of particle diameter distribution of the silica particles.