Abstract: An image display medium capable of providing an image display with less change in the image density, with less change in the uniformness of the density and at stable density contrast even after repetitive rewriting over a long period of time, and an image forming apparatus using the image display medium are provided. The image display medium and image forming apparatus have a pair of facing substrates, at least two kinds of particles sealed in a space between the pair of the substrates in which the at least two kinds of particles have a characteristic that at least one kind of them is positively chargeable and at least one other kind of them is negatively chargeable, and the particles chargeable positively and negatively are of colors different from each other and a charge controller is internally added to one or both of the particles chargeable positively and negatively.

Abstract: A crosslinked polymer particle can be obtained by carrying out a crosslinking reaction between a non-crosslinked polymer particle containing a succinimidoxycarbonyl group and a compound having two or more amino groups.

Abstract: The present invention relates to a maleimide group-containing polymer particle containing a crosslinked polymer particle containing a group represented by the following formula (1) and to a method of producing the maleimide group-containing crosslinked polymer particle by reacting hydroxymethylmaleimide with a hydroxyl group-containing polymer particle obtained by introducing a polyethylene glycol into a crosslinked polymer particle: wherein n denotes an integer of 1 or more.

Abstract: The present invention provides a method for producing hydroxyl group-containing polymer particles including causing cross-linked polymer particles containing a (meth)acrylate polymer to react in the presence of a metal-containing ester-exchange reaction catalyst with at least one compound selected from the group consisting of a compound including at least two hydroxyl groups and a compound including at least one primary amino group and at least one hydroxyl group, the cross-linked polymer particles comprising the (meth)acrylate polymer represented by the following formula (I): wherein R1 represents a hydrogen atom or a methyl group; R2 to R4 may be the same or different from each other, and each independently represents a substituted or non-substituted alkyl group or a substituted or non-substituted aryl group, any one of which has 1 to 12 carbon atoms; and n represents an integer of 1 or more.

Abstract: An image display medium capable of displaying an image showing little change of the image density, and also little change of the image density uniformity, and being stable in density contrast, even when repeatedly rewritten over a long period, and an image formation apparatus are provided. The image display medium includes a pair of substrates disposed opposing to each other; and particle groups including at least two types of particles sealed in a space between the pair of the substrates, at least one type thereof having a positively chargeable property, and at least one of others having a negatively chargeable property, and the positively and negatively chargeable types of particles being different colors. The value of a coefficient of variation in each particle size distribution of both the positively and negatively chargeable types of particles is approximately not more than 15%.

Abstract: The present invention relates to a method of producing a functional polymer particle having at least one kind of functional group selected from the following structure group (A), which comprises the step of reacting a non-crosslinked polymer particle having a succinimidoxycarbonyl group with a compound having at least one kind of functional group selected from the following structure group (A) and at least one functional group selected from the group consisting of a primary amino group and a secondary amino group: 1

Abstract: A method of producing a non-crosslinked polymer particle having in a side chain thereof a succinimidoxycarbonyl group represented by the following structural formula (1): 1

Abstract: A crosslinked polymer particle can be obtained by carrying out a crosslinking reaction between a non-crosslinked polymer particle containing a succinimidoxycarbonyl group and a compound having two or more amino groups.

Abstract: An image display medium capable of displaying an image showing little change of the image density, and also little change of the image density uniformity, and being stable in density contrast, even when repeatedly rewritten over a long period, and an image formation apparatus are provided. The image display medium includes a pair of substrates disposed opposing to each other; and particle groups including at least two types of particles sealed in a space between the pair of the substrates, at least one type thereof having a positively chargeable property, and at least one of others having a negatively chargeable property, and the positively and negatively chargeable types of particles being different colors. The value of a coefficient of variation in each particle size distribution of both the positively and negatively chargeable types of particles is approximately not more than 15%.

Abstract: An electrophotographic toner excellent in dispersibility of a colorant, excellent in fixing property at a low temperature and having a broad fixing latitude of good offset resisting property, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided. The electrophotographic toner is provided that contains a binder resin and a colorant, in which the binder resin contains a crystalline polyester containing a carboxylic acid of two or more valences having a sulfonic acid group as a monomer component, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided.

Abstract: An image display medium capable of providing an image display with less change in the image density, with less change in the uniformness of the density and at stable density contrast even after repetitive rewriting over a long period of time, and an image forming apparatus using the image display medium are provided. The image display medium and image forming apparatus have a pair of facing substrates, at least two kinds of particles sealed in a space between the pair of the substrates in which the at least two kinds of particles have a characteristic that at least one kind of them is positively chargeable and at least one other kind of them is negatively chargeable, and the particles chargeable positively and negatively are of colors different from each other and a charge controller is internally added to one or both of the particles chargeable positively and negatively.

Abstract: An electrophotographic toner excellent in dispersibility of a colorant, excellent in fixing property at a low temperature and having a broad fixing latitude of good offset resisting property, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided. The electrophotographic toner is provided that contains a binder resin and a colorant, in which the binder resin contains a crystalline polyester containing a carboxylic acid of two or more valences having a sulfonic acid group as a monomer component, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided.

Abstract: An electrophotographic toner containing a binder resin and a colorant, wherein at the angular frequency of 1 rad/sec and 30° C., a storage elastic modulus (G′30) is at least 1×105 Pa and a loss elastic modulus (G″30) is at least 1×105 Pa; a melting point is in the temperature region of 45 and 110° C.; when a common logarithm of G′ is plotted against the temperature and G′ at melting point +20° C. is represented by G′ (Tm+20) and G′ at melting point +50° C. is represented by G′ (Tm+50) the condition of the following formula (1) is satisfied |logG′(Tm+20)−logG′(Tm+50)|≦1.5  (1); and when a common logarithm of G″ is plotted against the temperature and G″ at melting point +20° C. is represented by G″ (Tm+20) and G″ at melting point +50° C.