An external additive for toner comprising a particle of a silicon polymer having a siloxane bond and a Si—O—C bond, wherein in an FT-IR spectrum of the external additive obtained by an ATR method, a maximum peak is present in a range of from 1030 cm.sup.−1 to 1070 cm.sup.−1, where an average intensity in a range of from 1015 cm.sup.−1 to 1025 cm.sup.−1 of the spectrum is denoted by A and an average intensity in a range of from 1085 cm.sup.−1 to 1095 cm.sup.−1 is denoted by B, the A and the B satisfy a following formula (1):

[00001]$\begin{array}{cc}0.55\le A/B\le 1.5.& \left(1\right)\end{array}$

An external additive for toner comprising a particle of a silicon polymer having a siloxane bond and a Si—R.sup.1 bond, wherein the R.sup.1 represents an alkyl group having from 1 to 6 carbon atoms, in a chart obtained by .sup.29Si—NMR measurement of the external additive, where a total peak area attributed to the external additive is denoted by A, and a peak area attributed to the Si—R.sup.1 bond is denoted by B, a following formula (1) is satisfied, and in the chart obtained by .sup.29Si—NMR measurement of the external additive, where a total peak area attributed to the silicon polymer is denoted by SA, and a peak area attributed to a T unit structure is denoted by S3, a following formula (2) is satisfied;

[00001]$\begin{array}{cc}0.260\le B/A\le 0\mathrm{.450}& \left(1\right)\\ 0.00\le S3/\mathrm{SA}\le 0\mathrm{.50}.& \left(2\right)\end{array}$

A fine particle of a silicon polymer having a siloxane group and a silanol group, wherein a moisture adsorption amount of the fine particle at a temperature of 30° C. and a humidity of 80% RH is from 1.0 mg/g to 22.0 mg/g, an amount of the silanol group of the fine particle measured by a titration method using KOH is from 0.012 mmol/g to 0.120 mmol/g, and a number average particle diameter of primary particle of the fine particle is from 0.05 μm to 0.30 μm.

A toner comprising a toner particle comprising a resin A, and an external additive A, wherein the resin A is a resin represented by formula (1) below, the resin A is present at the surface of the toner particle, the external additive A is a fine particle containing silicon, the average value of the shape factor SF-1 of the external additive A is from 105 to 120, the average value of the shape factor SF-2 of the external additive A is from 100 to 130.

##STR00001##

Toner contains toner base particles and an organosilicon polymer on the surface of the toner base particles, and silica particles are added to the toner as an external additive. The surface roughness Rz of an intermediate transfer belt, against which a blade abuts, in the width direction of the intermediate transfer belt perpendicular to the belt conveying direction is larger than the average particle diameter Ry of the organosilicon polymer and is smaller than the average particle diameter Rk of the silica particles.

A toner comprising a toner particle and an external additive, wherein the external additive comprises a composite particle comprising an organosilicon polymer fine particle covering a surface of an alumina particle, a coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle is 1 to 50 area %, and given A (nm) as a number-average particle diameter of primary particles of the organosilicon polymer fine particle and B (nm) as a number-average particle diameter of primary particles of the alumina particle, following formulae (I) and (II) are satisfied:

A≤90  (I)

100≤B≤1000  (II).

A negative-charging toner comprising a toner particle comprising a binder resin and an organic-inorganic composite fine particle comprising resin fine particles and inorganic fine particles A, wherein the organic-inorganic composite fine particle is negative charging, the organic-inorganic composite fine particle has a structure in which at least a part of the inorganic fine particle A is embedded in the resin fine particle, a number average particle diameter Db of the organic-inorganic composite fine particle is 50 to 350 nm, and a plurality of convex portions derived from the inorganic fine particles A are present on the surface of the organic-inorganic composite fine particle.

Toner contains toner base particles and an organosilicon polymer on the surface of the toner base particles. After a toner image is transferred from an intermediate transfer belt to a transfer material, residual toner on the intermediate transfer belt is collected into a belt cleaning device by a blade. A CPU executes supply control of supplying toner from a developing device toward the blade via a photosensitive drum and via the intermediate transfer belt on the basis of the counter accumulated value that correlates with the amount of organosilicon polymer adhering to the blade.

An external additive for toner, wherein the external additive is an organosilicon polymer particle, and defining A (nm) as the number-average particle diameter of primary particles of the external additive measured using a scanning electron microscope, and defining B (nm) as the number-average particle diameter of the external additive measured in accordance with a centrifugal sedimentation method, the A and the B satisfy a following Expression (1):

1.5≤B/A≤3.0  (1).

A toner comprising a toner particle that contains a binder resin and fine particles A at the surface of the toner particle, wherein the fine particles A are organosilicon polymer fine particles, the organosilicon polymer fine particles have a number-average primary particle diameter of 30 nm to 500 nm, the organosilicon polymer fine particles have an attachment index for a polycarbonate film of not more than 3.5, the organosilicon polymer fine particles penetrate into the toner particle in a penetration depth b (nm), and protrude from the toner particle in a protrusion height c (nm), and b and c satisfy 0.05≤b/(b+c)≤0.40.