A photoresponsive polymer includes a structural unit represented by the following general formula (1), the photoresponsive polymer being fluidized by light irradiation, and reversibly non-fluidized:

[Chemical formula 1]

R.sub.1—Z.sub.1═Z.sub.2—R.sub.2  General formula (1) in the formula, Z.sub.1 and Z.sub.2 each represent CH or N, and Z.sub.1≠Z.sub.2, R.sub.1 represents an aromatic hydrocarbon group having a substituent R.sub.a selected from the group consisting of an alkyl group, an alkoxy group, and a halogen atom at each of two ortho positions with respect to Z.sub.1, R.sub.2 represents an aromatic heterocyclic group with or without a substituent, and at least one of the R.sub.1 and the R.sub.2 is bonded to a group containing a structure derived from a polymerizable group.

A method for producing an electrostatic image developing toner includes mixing toner particles containing an amorphous resin with additive particles. A mixing device used in the mixing includes a stirring vessel, a stirring blade, and a jacket configured to cool the stirring vessel, and condition (1) and condition (2) are satisfied. Condition (1): an internal temperature Ti of the mixing device in the mixing and a glass transition temperature Tg of the amorphous resin contained in a near-surface portion of the toner particles satisfy Tg−50° C.≤Ti<Tg (inequality 1). Condition (2): 0.08≤ (Pm−P0)/w≤0.50 (inequality 2) is satisfied. In inequality 2, Pm represents an average power (kW) of a motor for driving the stirring blade of the mixing device in the mixing, P0 represents an idling power (kW) of the motor, and w represents a total mass (kg) of the toner particles and the additive particles in the mixing device.

An electrostatic image developing toner includes toner particles containing a binder resin. In a differential scanning calorimetry curve of the toner particles, Tg1 is 58° C. or more and 68° C. or less, and Tg1−Tg2 is 20° C. or more and 40° C. or less, where Tg1 is a lowest onset temperature in an endothermic change during a first temperature increase, and Tg2 is a lowest onset temperature in an endothermic change during a second temperature increase.

A white toner for electrostatic image development contains white toner particles that contain a binder resin and a white pigment and satisfy condition 1 below:

condition 1: a grain size distribution index GSD.sub.vL of the white toner particles satisfies formula (1) below, and a ratio of a number of white toner particles having a diameter of 3 μm or less to a total number of white toner particles is 1% by number or more and less than 6% by number:

1.2≤GSD.sub.vL(=D.sub.84v/D.sub.50v)≤1.5   formula (1):

(in formula (1), D.sub.84v is a particle diameter at which a cumulative frequency cumulated from a small diameter side in a volume-based particle size distribution is 84%, and D.sub.50v is a particle diameter at which the cumulative frequency cumulated from the small diameter side in the volume-based particle size distribution is 50%).

A toner, comprising a toner particle comprising a binder resin, wherein the binder resin comprises an amorphous polyester and a crystalline polyester; (i) a weight-average molecular weight of a soluble matter of the crystalline polyester in o-dichlorobenzene at 100° C. is 1500 to 4900; (ii) the crystalline polyester comprises a modified crystalline polyester having at least one terminal-modified structure selected from among a structure in which a hydroxy group at a main chain terminal of the crystalline polyester is terminal-modified with a C16 to C31 aliphatic monocarboxylic acid, and a structure in which a carboxy group at a main chain terminal of the crystalline polyester is terminal-modified with a C15 to C30 aliphatic monoalcohol; and (iii) a content ratio of the terminal-modified structure in the crystalline polyester is 80.0 mol % or higher.

A toner for developing an electrostatic charge image includes toner particles that include a binder resin, a releasing agent, a brilliant pigment, and an aminocarboxylic acid compound.

A toner for developing an electrostatic charge image contains toner particles containing at least one binder resin, a release agent, and a coloring agent, and a cross-sectional image of the toner particles meets requirements (1) and (2): requirement (1), an average of ten or more domains, per toner particle, of the release agent have an area of 0.5% or more and 5.0% or less of the area of the toner particle; requirement (2), in a Voronoi tessellation generated from the centroids of the domains of the coloring agent, the mean area of the Voronoi cells is 0.020 μm.sup.2 or more and 0.060 μm.sup.2 or less, and the standard deviation of the areas of the Voronoi cells is 0.010 μm.sup.2 or less.

A toner, comprising a toner particle comprising a binder resin and a water-soluble polyvalent metal salt, wherein a main component of the binder resin is a polyester resin having specific acid value, the water-soluble polyvalent metal salt is a chloride, nitrate or sulfate of the specific metal, the water-soluble polyvalent metal salt has a solubility in water at 25° C. of 30 to 200 g/100 mL, in a cross-sectional observation of the toner particle, a proportion of the area of domains having a concrete surface area, relative to the total area of domains derived from the water-soluble polyvalent metal salt, is 80 to 100 area %, the expression below is satisfied, where At (area %) denotes the proportion of the total area of domains and Fm (atomic %) denotes the proportion of the polyvalent metal atom relative to the atoms in the toner as detected by X-ray fluorescence analysis.

0.02≤At/Fm≤0.10

Described herein is a printed photovoltaic cell comprising an anode; an LEP printed cathode; and an LEP printed photovoltaic layer disposed between the anode and the cathode. The photovoltaic layer comprises a material with a perovskite structure having a chemical formula selected from ABX.sub.3 and A.sub.2BX.sub.6 and a thermoplastic resin comprising a copolymer of an alkylene monomer and a monomer having acidic side groups; and/or a copolymer of an alkylene monomer and an ethylenically unsaturated monomer comprising an epoxide; and/or a copolymer of an alkylene monomer, an ethylenically unsaturated monomer comprising an epoxide, and a monomer selected from a monomer having acidic side groups, a monomer having ester side groups and a mixture thereof. The printed cathode comprises: a thermoplastic resin; and electrically conductive metal particles. Also described herein is a method of producing the printed photovoltaic cell and an ink set for use in the method.

A toner composition having improved toner usage efficiency, wherein toner particles having an average size range of 1-25 μm may be mixed with an extra particulate additive package including a first small silica surface treated with both a silane and an aminosilane having a primary particle size of about 5 nm-20 nm, a second fumed silica having a primary particle size of 30 nm-60 nm, a third silica having a primary particle size of about 70 nm-120 nm, an electro-conductive titania having a primary particle size of 30 nm-60 nm and an acicular titania having a size of about 1.6 μm to 1.7 μm in length and about 130 nm in diameter. An alternative embodiment of the extra particulate additive package does not include a third silica having a primary particle size of about 70 nm-120 nm.