Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2002-04-19
2004-08-24
Goodrow, John L (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C430S110300, C430S110400, C430S045320, C399S294000
Reexamination Certificate
active
06780558
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an image forming method, an image forming apparatus and a developing toner to be used therein.
BACKGROUND OF THE INVENTION
Recently, electrophotography is utilized in various fields, for example, not only in the field of monochromatic copying machine but in the fields of printer as the output terminal of computer, color copy machine and color printer.
Requirement to the image quality is made higher accompanied with the progress of the utilization. As the color image formation method, a method in which plural images are piled on a photoreceptor and then the images are transferred all at once onto an image support and a method in which the plural images are piled on an intermediate transfer member and transferred onto the image forming support have been know. These methods, however, has a shortcoming that the image forming speed of full color image is become to ¼ or less of that of the monochromatic image formation since the color images are successively formed and fixed after finishing of the full color image formation.
A method so called tandem system is proposed to solve the problem. In such the method, set of a static latent image forming member or a photoreceptor and a developing device, namely an image forming unit, for each of the colors are arranged in the image forming apparatus.
This method is noticed as an image forming method with a very high efficiency since there is no difference in the printing speed of a monochromatic image and that of a full color image even though the mechanism of the apparatus is become complex because the photoreceptor and the developing device are necessary for each color. In this image forming method, the images formed in each color developing devices are once transferred onto an intermediate transfer member and then transferred onto an image support (transfer material) or the each color toner images are successively and directly transferred onto the image forming support and fixed.
In such the system, however, the image formed on (intermediate) image support member repeatedly receives an effect of static treatment such as corona discharge. Therefore, the degree of the influence of such the effect on the firstly formed image is different from that on the lastly formed image. Such the difference of the influence degree is the same when the toner images are directly transferred to the image support.
The images are further subjected to such the static influence largely in the course of the transferring process and the fixing process. Consequently, repulsion and off-set caused by the static force are occurred, and problems of blur character due to toner scattering and discrepancy of color images tend to be raised.
Therefore, the tandem system is insufficient as the color forming method to form a high quality image.
SUMMARY OF THE INVENTION
The object of the invention is to provide an image forming method, an image forming apparatus and a developing toner to be used in them by which a high quality image without occurrence of the blur character due to toner scattering and image discrepancy (drift of colors) by the tandem color image forming system.
The invention and its embodiments are described below.
An image forming method comprising the steps of
developing latent images each formed on a static latent image forming member by serially arranged plural image forming units each including a toner to form toner images, respectively,
successively transferring the toner images onto an image support so as to form a piled up image, and
fixing the piled up image by a fixing device having a rotatable heating member including a heater fixed therein and a pressing member,
wherein the toner for developing the latent image has a variation coefficient of the shape coefficient of not more than 16% and a number variation coefficient of the particle diameter distribution in number of not more than 27%.
It is preferable in the image forming method that the developing toner contains toner particles each having a shape coefficient within the range of from 1.0 to 1.6 in a ratio of not less than 65% in number.
The developing toner preferably contains toner particles each having a shape coefficient within the range of from 1.2 to 1.6 in a ratio of not less than 65% in number.
The developing toner preferably contains toner particles having no corner in a ratio of not less than 50% in number.
The developing toner preferably has a number average diameter of from 3 to 8 &mgr;m.
It is preferable that the sum M of a relative frequency of the toner particles included in the highest frequency class m1 and a relative frequency of the toner particles included the next high frequency class m2 is not less than 70% in a histogram showing a particle diameter distribution in number classified into plural classes every 0.23 of natural logarithm ln D graduated on the horizontal axis of the histogram, where D is the diameter of the toner particle in &mgr;m.
The developing toner is preferably one prepared by polymerizing a polymerizable monomer in an aqueous medium.
The developing toner is preferably one prepared by association of resin particles in an aqueous medium.
An image forming method comprising the steps of
developing latent images each formed on a static latent image forming member by serially arranged plural image forming units each including a toner to form toner images, respectively,
successively transferring the toner images onto an image support member so as to form a piled up image, and
fixing the piled up image by a fixing device having a rotatable heating member including a heater fixed therein and a pressing member,
wherein the toner for developing the latent image contains toner particles having no corner in a ratio of not less than 50% and a number variation coefficient of the particle diameter distribution in number of not more than 27%.
An image forming method comprising the steps of
developing latent images each formed on a static latent image forming member by serially arranged plural image forming units each including a toner to form toner images, respectively,
successively transferring the toner images onto an image support member so as to form a piled up image, and
fixing the piled up image by a fixing device having a rotatable heating member including a heater fixed therein and a pressing member,
wherein the toner for developing the latent image contains toner particles each having a shape coefficient within the range of from 1.2 to 1.6 in a ratio of not less than 65% in number and a variation coefficient of the shape coefficient of not more than 16%.
An image forming apparatus for
developing latent images each formed on a static latent image forming member by serially arranged plural image forming units each including a toner to form toner images, respectively,
successively transferring the toner images onto an image support member so as to form a piled up image, and
fixing the piled up image by a fixing device having a rotatable heating member including a heater fixed therein and a pressing member,
wherein the toner for developing the latent image each has a variation coefficient of the shape coefficient of not more than 16% and a number variation coefficient of the particle diameter distribution in number of not more than 27%.
An image forming apparatus for
developing latent images each formed on a static latent image forming member by serially arranged plural image forming units each including a toner to form toner images, respectively,
successively transferring the toner images onto an image support member so as to form a piled up image, and
fixing the piled up image by a fixing device having a rotatable heating member including a heater fixed therein and a pressing member,
wherein the toner for developing the latent image contains toner particles having no corner in a ratio of not less than 50% and a number variation coefficient of the particle diameter distribution in number of not more than 27%.
An image forming apparatus for
developing latent images each formed on a static latent image forming m
Kouno Shigenori
Shirose Meizo
Yamada Hiroyuki
Yamazaki Hiroshi
Goodrow John L
Konica Corporation
Squire Sanders & Dempsey L.L.P.
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