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US 6,122,468 AGranted
Method and apparatus for forming toner images
AssigneeRicoh Company, Ltd.
InventorsKoji Sakamoto, Akio Kosuge
Life of this patent
Estimating the term…
Abstract
In an electrophotographic image forming apparatus, a photoconductive element includes a photoconductive film having a thickness of 15 .mu.m or below. A light beam having a diameter of 50 .mu.m or below optically forms a latent image on the photoconductive element. Toner is caused to deposit on a dot image in an amount 1.2 times greater than on an area image. This is successful to minimize the variation of image quality and to render dots inconspicuous. The method of forming toner images is also included.
Claims27
An image forming apparatus comprising:
- a photoconductive element including a photoconductive film having a thickness of 15 .mu.m or below;
- an exposing device for forming an electrostatic latent image in a form of dots on said photoconductive element by selectively turning on or turning off a light beam having a beam diameter of 50 .mu.m or below in terms of a 1/e.sup.2 diameter and intense enough to sufficiently attenuate a potential deposited on said photoconductive element;
- and
- a developing device for developing the latent image with a dry developer to thereby form a corresponding toner image;
- wherein tonality is rendered on the basis of a density of the dots for a unit area, and wherein the toner deposits on the dots in an amount 1.2 times greater than an amount to deposit on an area image for a given uniform density and a given unit area.
2 more elements
A copier comprising:
- an image reading device for reading a document;
- and
- an image forming apparatus for electrophotographically forming an image read by said image reading means;
- said image forming apparatus comprising:
- a photoconductive element including a photoconductive film having a thickness of 15 .mu.m or below;
- an exposing device for forming an electrostatic latent image in a form of dots on said photoconductive element by selectively turning on or turning off a light beam having a beam diameter of 50 .mu.m or below in terms of a 1/e.sup.2 diameter and intense enough to sufficiently attenuate a potential deposited on said photoconductive element;
- and
- a developing device for developing the latent image with a dry developer to thereby form a corresponding toner image;
- wherein tonality is rendered on the basis of a density of the dots for a unit area, and wherein the toner deposits on the dots in an amount 1.2 times greater than an amount to deposit on an area image for a given uniform density and a given unit area.
6 more elements
A copier comprising:
- an image reading device for reading a document;
- and
- an image forming apparatus for electrophotographically forming a color image read by said image reading device;
- said image forming apparatus comprising:
- a photoconductive element including a photoconductive film having a thickness of 15 .mu.m or below;
- an exposing device for forming, color by color, an electrostatic latent image in a form of dots on said photoconductive element by selectively turning on or turning off a light beam having a beam diameter of 50 .mu.m or below in terms of a 1/e.sup.2 diameter and intense enough to sufficiently attenuate a potential deposited on said photoconductive element;
- and
- a plurality of developing devices each for developing a particular electrostatic latent image with a dry developer of particular to thereby produce a corresponding toner image;
- and
- a transferring device for transferring toner images of different colors produced by said plurality of developing devices to a recording medium one upon the other to thereby form a composite color image;
- wherein tonality is rendered on the basis of a density of the dots for a unit area, and wherein the toner deposits on the dots in an amount 1.2 times greater than an amount to deposit on an area image for a given uniform density and a given unit area.
8 more elements
An electrophotographic image forming method comprising the steps of:
- an exposing step for forming on a photoconductive element including a photoconductive film having a thickness of 15 .mu.m or below an electrostatic latent image in a form of dots by selectively turning on or turning off a light beam having a beam diameter of 50 .mu.m or below in terms of a 1/e.sup.2 diameter and intense enough to sufficiently attenuate a potential deposited on said photoconductive element;
- and
- a developing step for developing the latent image with a dry developer to thereby form a corresponding toner image;
- wherein tonality is rendered on the basis of a density of the dots for a unit area, and wherein the toner deposits on the dots in an amount 1.2 times greater than an amount to deposit on an area image for a given uniform density and a given unit area.
1 more element
An image forming apparatus comprising:
- a photoconductive element;
- charging means for uniformly charging a surface of said photoconductive element;
- exposing means for exposing the charged surface of said photoconductive element in a form of dots to thereby form an electrostatic latent image;
- developing means for developing the latent image to thereby produce a corresponding toner image;
- transferring means for transferring the toner image from said photoconductive element to a recording medium;
- and
- fixing means for fixing the toner image on the recording medium;
- wherein said charging means deposits a charge potential of 350 V to 550 V in absolute value on said photoconductive element, and wherein use is made of toner having a tinting strength which causes said toner to deposit on the paper in an amount of 0.3 mg/cm.sup.2 to 0.7 mg/cm.sup.2 when measured after fixation.
5 more elements
Dependencies are inferred from the claim text.