Toner for developing electrostatic latent image and image forming method using the same

Abstract

The toner of the present invention is characterized in that the charges rise up rapidly, the charge quantity is not insufficient nor excessive, the photoreceptor contamination is minimized and the toner is endurable under harsh conditions and against the high stress usage. The magnetic particle contained in the toner is of average particle size 0.01 mum through 0.50 mum, is of octahedron shape that is a convex polyhedron surrounded by eight triangles as a basis, each of vertexes and edges of the octahedron being in a curved surface shape and having a portion that can be taken as a straight line on the outer periphery of a projected image of said octahedron. The sphericity of the toner is 0.94 through 0.98. Here, the sphericity is defined by C2 / C1, where C1 is a circumferential length of an image projected on a plane and C2 is a circumferential length of an assumed circle area as same as that of the projected image. Further, a number content of the toner of particle size 0.6 mum through 2.0 mum is smaller than 10%.

Description

technical field [0001] The present invention relates to a toner for developing an electrostatic latent image and an image forming method using the toner, and particularly relates to optimizing the shape of magnetic particles added to the toner and the shape of the toner. Background technique [0002] In electrophotographic image forming devices, such as laser printers, copiers, facsimile machines, and their hybrid devices, firstly, the electrostatic latent image holding member, that is, the photoreceptor is uniformly charged, secondly, the photoreceptor is exposed, thereby forming an electrostatic latent image, and thirdly The latent image is developed with toner, the fourth is to transfer the toner image to paper or an intermediate transfer member, and finally the transferred toner image is fixed on the paper. [0003] Although dry developing and wet developing methods exist, dry developing is more widely used than wet developing. In addition, dry developers are classified...

AI Technical Summary

Problems solved by technology

However, it has a disadvantage in that, similarly to spherical magnetic toners, magnetic toners are overcharged, thereby possibly deteriorating image quality

First of all, the conventional toner that adds magnetic powder inside the toner has the disadvantages that it cannot be charged quickly and is overcharged and unstable to environmental conditions

Second, another disadvantage is that if the toner sphericity is too low (i.e., far from a sphere), the interior of the full-width image cannot be transferred well, while if the toner sphericity is too high (i.e., almost spherical), the photoreceptor roller is not cleaned well due to the toner slipping onto the cleaning blade

Third, the content of toner smaller than 2 μm is abundant, and the toner charge distribution becomes broad, thereby causing background fogging, photoreceptor cleaning, and deterioration of long-term durability

In particular, toner tends to adhere to the developing roller and photoreceptor, thereby deteriorating the above-mentioned image transferability and long-term stability

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