Fluorescing yellow toner particles and methods of use

1. A fluorescing yellow polymeric toner particle comprising a polymeric binder phase, and having distributed therein:

one or more non-fluorescing yellow colorants having one or more absorbance peak wavelengths of at least 480 nm and up to and including 600 nm, and one or more fluorescing yellow colorants having one or more emission peak wavelengths of at least 480 nm and up to and including 600 nm,

wherein:

the molar ratio of the one or more fluorescing yellow colorants to the one or more non-fluorescing yellow colorants is such that the covering power of the fluorescing yellow polymeric toner particle is greater than the covering power of non-fluorescing yellow polymeric toner particles having the same composition and size except that the one or more fluorescing yellow colorants are absent,

the molar ratio of the one or more fluorescing yellow colorants to the one or more non-fluorescing yellow colorants is such that the L* value of the one or more non-fluorescing yellow colorants, when present in a non-fluorescing yellow polymeric toner particle comprising the same polymeric binder phase, is increased by at least 50% in the presence of the one or more fluorescing yellow colorants in the non-fluorescing yellow polymeric toner particle the molar ratio of the one or more fluorescing yellow colorants to one or more non-fluorescing yellow colorants is at least 2:1 and up to 8:1, and

the one or more non-fluorescing yellow colorants are selected from group consisting of coumarins, naphthalimides, perylenes, and anthrones.

2. The fluorescing yellow polymeric toner particle of claim 1 , wherein the one or more fluorescing yellow colorants are selected from the group consisting of coumarins, naphthalimides, perylenes, and anthrones.

3. The fluorescing yellow polymeric toner particle of claim 1 , wherein the polymeric binder phase comprises one or more polyesters or styrene-acrylate copolymers.

4. The fluorescing yellow polymeric toner particle of claim 1 having a mean volume weighted diameter (D vol ) before fixing of at least 4 μm and up to and including 15 μm.

5. The fluorescing yellow polymeric toner particle of claim 1 , wherein the molar ratio of the one or more fluorescing yellow colorants to the one or more non-fluorescing yellow colorants is such that the covering power of the fluorescing yellow polymeric toner particle to the covering power of the non-fluorescing yellow polymeric toner particles having the same composition and size except that the one or more fluorescing yellow colorants are absent, is at least 1:1 and up to and including 10:1.

6. The fluorescing yellow polymeric toner particle of claim 1 , wherein the total amount of the one or more non-fluorescing yellow colorants is up to and including 40% of the total amount of the one or more fluorescing yellow colorants, by weight.

7. A two-component developer comprising carrier particles and one or more of the fluorescing yellow polymeric toner particles of claim 1 .

8. The fluorescing yellow polymeric toner particle of claim 1 , wherein:

the one or more fluorescing yellow colorants are selected from the group consisting of coumarins, naphthalimides, perylenes, and anthrones,

the one or more non-fluorescing yellow colorants and one or more fluorescing yellow colorants, independently have one or more absorbance peak wavelengths of at least 480 nm and up to and including 580 nm, and

the fluorescing yellow polymeric toner particle has a mean volume weighted diameter (D vol ) before fixing of at least 4 μm and up to and including 15 μm.