US 12,228,881 B2Granted

Toner, developer, process cartridge, image forming apparatus, and image forming method

AssigneeRicoh Company, Ltd.

InventorsShoki Matsuda, Keisuke Tada, Yasuyuki Sanui

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Abstract

Yellow toner with excellent cleanability, transferability and device contamination resistance is provided. When intensity of spectrum at wavenumber λ, at which total intensity of Raman spectrums of toner particles from 950 cm−1 through 3,250 cm−1 in Raman spectroscopy of toner is maximum, is normalized to 1, and distribution is generated for ≥300 particles regarding LC calculated by [LC (%)=CH5 rate (%)−CHc rate (%)] based on CHc rate (%) defined as [(Inc−Iave)/Iave]×100 and CHs rate (%) defined as [(Ins−Iave)/Iave]×100 where In and Ins represent integrated intensities of spectrums of center and surface portions of each particle from 2,750 cm−1 through 3,250 cm−1, and Iave represents average of Inc and Ins of all particles, percentage by number of particles having LC deviating from LC distribution median by absolute value of ≥25.0; is ≥1.0% by number and ≤25.0% by number.

A yellow toner, comprising:

a binder resin;
and
a pigment,
wherein in a case where an intensity of a Raman spectrum of each toner particle at a wavenumber λ, at which a total intensity obtained by summing up Raman spectrums of toner particles that occur in a wavenumber range of 950 cm−1 or greater and 3,250 cm−1 or less in Raman spectroscopy of the yellow toner is maximum, is normalized to 1, and when a distribution is generated for 300 or more toner particles regarding a Localization Coefficient (LC) that is calculated according to a formula (3) below based on a CHc rate defined by a formula (1) below and a CHs rate defined by a formula (2) below where In represents an integrated intensity of a Raman spectrum of a center portion of each toner particle that occurs in a wavenumber range of 2,750 cm−1 or greater and 3,250 cm−1 or less and an integrated intensity of a Raman spectrum of a surface portion of each toner particle that occurs in the wavenumber range of 2,750 cm−1 or greater and 3,250 cm−1 or less, and Iave represents an average value of the In, a percentage by number of toner particles having the LC that deviates from a median of the distribution of the LC by an absolute value of 25.0% or greater is 1.0% by number or greater and 25.0% by number or less,
CH
c
⁢
rate
⁢
(
%
)
=
[
(
I
nc
-
I
ave
)
/
I
ave
]
×
100
(
1
)
CH
s
⁢
rate
⁢
(
%
)
=
[
(
I
ns
-
I
ave
)
/
I
ave
]
×
100
(
2
)
LC
⁢
(
%
)
=
CH
s
⁢
rate
⁢
(
%
)
-
CH
c
⁢
rate
⁢
(
%
)
(
3
)
where Inc represents the integrated intensity of the Raman spectrum of the center portion of an n-th toner particle in the wavenumber range of 2,750 cm−1 or greater and 3,250 cm−1 or less,
Ins represents the integrated intensity of the Raman spectrum of the surface portion of the n-th toner particle in the wavenumber range of 2,750 cm−1 or greater and 3,250 cm−1 or less, and
Iave represents the average value of the In of the toner particles including their center portions and surface portions.

82 more elements

Facts

Application

18/536,261Filed 12 Dec 2023

Priority

JP 2022-20018915 Dec 2022

Published

US 2024/0210847 A127 Jun 2024

Granted

18 Feb 2025

Term ends

Not estimatedThe source records don’t support an estimate.

Classification8 codes

G03G 9/0821
With toner particles: characterised by physical parameters
G03G 9/09
With toner particles: colouring agents for toner particles
G03G 9/0926
Colouring agents for toner particles: characterised by physical or chemical properties
G03G 15/08
For developing: using a solid developer, e.g. powder developer

Abstract

Claims8