Toner, image forming apparatus using the same, image forming method using the same, and process cartridge

An image forming apparatus, comprising:

• a latent electrostatic image bearing member,
• a charging unit configured to charge the surface of the latent electrostatic image bearing member,
• an exposing unit configured to expose the charged surface of the latent electrostatic image bearing member to form a latent electrostatic image,
• a developing unit configured to develop the latent electrostatic image using a toner to form a visible image,
• a transfer unit configured to transfer the visible image onto a recording medium, and
• a fixing unit configured to fix the transferred image on the recording medium,
• wherein the toner comprises a binder resin, a colorant and a charge controlling agent,
• wherein the charge controlling agent comprises an aromatic oxycarboxylic acid metal compound having a trivalent or more central metal, the binder resin comprises a polyester resin (A) having a softening point Tm (A) of 120° C. to 160° C. and a polyester resin (B) having a softening point Tm (B) of 80° C. to less than 120° C., and at least any one of the polyester resins (A) and (B) contains 1,2-propane diol at a content of 65 mol% or more in a divalent alcohol component and can be obtained by condensation polymerizing an alcohol component substantially composed of only an aliphatic alcohol with a carboxylic acid component.

An image forming method, comprising:

• charging the surface of a latent electrostatic image bearing member,
• exposing the charged surface of the latent electrostatic image bearing member to form a latent electrostatic image,
• developing the latent electrostatic image using a toner to form a visible image,
• transferring the visible image onto a recording medium, and
• fixing the transferred image on the recording medium,
• wherein the toner comprises a binder resin, a colorant and a charge controlling agent,
• wherein the charge controlling agent comprises an aromatic oxycarboxylic acid metal compound having a trivalent or more central metal, the binder resin comprises a polyester resin (A) having a softening point Tm (A) of 120° C. to 160° C. and a polyester resin (B) having a softening point Tm (B) of 80° C. to less than 120° C., and at least any one of the polyester resins (A) and (B) contains 1,2-propane diol at a content of 65 mol% or more in a divalent alcohol component and can be obtained by condensation polymerizing an alcohol component substantially composed of only an aliphatic alcohol with a carboxylic acid component.

A process cartridge detachably mountable to an image forming apparatus main body, comprising:

• a latent electrostatic image bearing member, and
• a developing unit configured to develop a latent electrostatic image formed on the latent electrostatic image bearing member using a toner to form a visible image,
• wherein the toner comprises a binder resin, a colorant and a charge controlling agent,
• wherein the charge controlling agent comprises an aromatic oxycarboxylic acid metal compound having a trivalent or more central metal, the binder resin comprises a polyester resin (A) having a softening point Tm (A) of 120° C. to 160° C. and a polyester resin (B) having a softening point Tm (B) of 80° C. to less than 120° C., and at least any one of the polyester resins (A) and (B) contains 1,2-propane diol at a content of 65 mol% or more in a divalent alcohol component and can be obtained by condensation polymerizing an alcohol component substantially composed of only an aliphatic alcohol with a carboxylic acid component.