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公开(公告)号：JP2001175075A
公开(公告)日：2001-06-29
申请号：JP36204099
申请日：1999-12-21
Applicant: SHARP KK
Inventor： TOYOSHIMA TETSURO , AZUMA NOBUYUKI , NAKAJIMA YOSHINORI , IWAMATSU TADASHI , MUTO YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To prevent the occurrence of uneven density, fogging and irregularities in an image due to a mechanical fluctuation at a contact part between a toner carrier and an electrostatic latent image holding body, and to form an image of good quality even at the time of forming an image of high resolution. SOLUTION: At a developing position where the circumferential surface of a developing roller 10 comes into press contact with the surface of a photoreceptor drum 2, as for a nip pressure P applied to the developer roller 10, the deformation δ of the developing roller 10, and a nip width S as the contact width of the circumferential surface of the developing roller 10 with the surface of the photoreceptor drum 2 in the circumferential direction, a spring constant P/δ is set within an extent of 2-200, P>1 gf/mm, S>2 mm, P/S (the ratio of the nip pressure P to the nip width S) is set to be 0.5 to 7. The dispersion of the dot diameter of a toner image formed on the surface of the photoreceptor drum 2 is suppressed, then, the outline of the dot becomes clear.
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公开(公告)号：JP2002123071A
公开(公告)日：2002-04-26
申请号：JP2000315332
申请日：2000-10-16
Applicant: SHARP KK
Inventor： TOYOSHIMA TETSURO , IWAMATSU TADASHI , AZUMA NOBUYUKI , MUTO YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To provide an electrophotographic image pickup unit by which a toner image obtained by development is stuck by a desired ratio even in the case that a beam size is larger than a dot pitch. SOLUTION: In a digital electrophotographic image pickup process by which an electrostatic latent image is written in an electrified photoreceptor by using the exposure beam size Ds of a larger size than that of a picture element pitch Dp and is developed by the development, the non-saturation area of the light discharge characteristic of an photoreceptor is used at the image part of an isolated 1 line, and the saturation area of the light discharge characteristic or the developing γ characteristic of the photoreceptor is used at the image part at the time of (n) lines (n>=2).
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公开(公告)号：JP2001134027A
公开(公告)日：2001-05-18
申请号：JP2000142663
申请日：2000-05-16
Applicant: SHARP KK
Inventor： IWAMATSU TADASHI , TOYOSHIMA TETSURO , AZUMA NOBUYUKI , MUTO YOSHINORI , NAKAJIMA YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To provide a high-quality image forming device capable of faithfully reproducing a high-resolution image pattern over 600 to 1200 DpI. SOLUTION: In this image forming device, the diameter W of the peak intensity 1/e2 of an exposing beam used in an exposure device is twice or less times as large as (p), the value of a latent image spatial frequency characteristic function MTFltnt defined by the film thickness (1) of the photoreceptor and the dielectric constant εa of the photoreceptor, the thickness (m) of a developer layer and the dielectric constant εb of the developer layer and spatial frequency ωdefined by ω=ρ/p is >=0.3.
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公开(公告)号：JP2000351237A
公开(公告)日：2000-12-19
申请号：JP16572399
申请日：1999-06-11
Applicant: SHARP KK
Inventor： MUTO YOSHINORI , TOYOSHIMA TETSURO , IWAMATSU TADASHI , AZUMA NOBUYUKI , NAKAJIMA YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To improve the image reproducibility of both of a cycle line pattern and an isolated dot pattern without reducing the thickness of a photosensitive body even case of high resolution. SOLUTION: When exposure energy density applied when image data is a line pattern every other line is set to Eline (μJ/cm2), the exposure energy control part of an image forming apparatus controls exposure energy density Edot (μJ/cm2) applied when image data is one isolated dot pattern so as to satisfy the relation of the formula -0.11P+6.4
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公开(公告)号：JP2001287402A
公开(公告)日：2001-10-16
申请号：JP2000107058
申请日：2000-04-07
Applicant: SHARP KK
Inventor： MUTO YOSHINORI , TOYOSHIMA TETSURO , IWAMATSU TADASHI , AZUMA NOBUYUKI , NAKAJIMA YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To reproduce both isolated line patterns and isolated dot patterns of a high resolution by a high image quality without increasing costs because of the requirement for a high accuracy to process and position lenses and without decreasing a life of a photoreceptor because of thinning a photosensitive layer. SOLUTION: A pulse height (driving power) of driving pulses for every dot is changed by a power control means set to a laser driver 6 between the isolated dot pattern and the isolated line pattern. Images are formed by controlling a driving energy supplied to an LD 2 from the laser driver 6 in accordance with an image pattern. A reproducibility for the isolated dot pattern of a dot diameter of approximately 30 μm at the resolution of 1,200 dpi is improved, and also a reproducibility for the isolated line pattern is improved. Since the power control means which controls the pulse height of driving pulses for every dot according to the image pattern is used, the image reproducibility can be satisfied both for the isolated dot pattern and for the isolated line pattern.
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Patent Agency Ranking
公开(公告)号：JP2001253110A
公开(公告)日：2001-09-18
申请号：JP2000066539
申请日：2000-03-10
Applicant: SHARP KK
Inventor： MUTO YOSHINORI , TOYOSHIMA TETSURO , IWAMATSU TADASHI , AZUMA NOBUYUKI , NAKAJIMA YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To ensure good reproducibility for various image patterns without requiring control of exposing energy and to prevent deterioration of image quality due to wear of a photosensitive material without sacrifice of image reproducibility. SOLUTION: When the diameter of exposing spot is 60 μm, such an exposing energy band as the image size falls within an appropriate range for all image patterns does not exist and a different exposing energy must be set for each image pattern in order to confine the image size within an appropriate range for all image patterns. On the other hand, when the diameter of exposing spot is 30 μm or 15 μm, such an exposing energy band as the image size falls within an appropriate range for all image patterns exists and the image size can be confined within an appropriate range for all image patterns without requiring the control of exposing energy. When the diameter of exposing spot is set within one time of the dot pitch, image reproducibility is made appropriate for all image patterns with a constant exposing energy without requiring modulation of exposing energy.
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公开(公告)号：JP2000343756A
公开(公告)日：2000-12-12
申请号：JP16221699
申请日：1999-06-09
Applicant: SHARP KK
Inventor： NAKAJIMA YOSHINORI , TOYOSHIMA TETSURO , IWAMATSU TADASHI , AZUMA NOBUYUKI , MUTO YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To provide an image forming apparatus having superior image reproducibility with respect to images with various dot densities. SOLUTION: A control section 105 for controlling the exposing energy in this image forming apparatus comprises a reference image memory section 207 storing a plurality of reference images, an image discriminating section 201 for comparing and discriminating image information consisting of plural pieces of image information on the basis of the data in the reference image memory section 207 and an exposing energy density memory section 209 for storing the exposing energy density with respect to each reference image stored in the reference image memory section 207. The control section 105 further comprises an exposing energy density determining section 203 for determining an exposing energy density to be applied to a dot position with respect to each image information on the basis of the data from the image discriminating section 201 and data in the exposing energy density memory section 209 and a laser driver 205 for driving a laser device in an exposing section in accordance with the data from the exposing energy density determining section 203.
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公开(公告)号：JP2000242081A
公开(公告)日：2000-09-08
申请号：JP3912799
申请日：1999-02-17
Applicant: SHARP KK
Inventor： TOYOSHIMA TETSURO , IWAMATSU TADASHI , AZUMA NOBUYUKI , MUTO YOSHINORI , NAKAJIMA YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To enhance the developing quality by making the electrifying amount large when toner is fed by a toner carrier and making it small when an electrostatic latent image is developed. SOLUTION: The one-component non-magnetic toner is supplied to the toner carrier 1 from a toner supply means 2 and electrostatically attracted so as to be attached to the carrier 1 with a large electrifying amount. Besides, electric charge is reduced from the toner by an electric charge adjustment means 3 such as a conductive roller to which potential is given by a triboelectrifying member (3a) or a volt source (33) when the toner is fed so that developer amount that the toner is attached to the electrostatic latent image is made large. Thus, the developing quality is enhanced.
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公开(公告)号：JP2000177171A
公开(公告)日：2000-06-27
申请号：JP36233198
申请日：1998-12-21
Applicant: SHARP KK
Inventor： YAMADA MASANORI , TOYOSHIMA TETSURO , IWAMATSU TADASHI , NAKAJIMA YOSHINORI , MUTO YOSHINORI
Abstract: PROBLEM TO BE SOLVED: To obtain an image faithful to an original data by setting the energy density for exposing image information of isolated pattern higher than that for exposing image information of every other dot or line pattern. SOLUTION: Dot diameter d of an isolated dot can be enlarged by increasing the energy density for exposure and attenuation of surface potential of a photosensitive body can be increased. Consequently, a pattern (1 by 1 pattern) 102 of black lines of 1 dot width and white lines of 1 dot width (nonprinting part) can be reproduced simultaneously with an isolated dot pattern 101 by varying the density of exposing energy being thrown in. For example, exposing energy is thrown in at a density Eb of about 1.2 μJ/cm2 when the 1 by 1 pattern 102 is exposed, and thrown in at a density Ea (Ea>Eb) of about 3.6 μJ/cm2 when the isolation pattern 101 is exposed. Consequently, the 1 by 1 pattern is formed at a duty of about 50% and the isolation pattern 101 is formed with dot diameter of about 28 μm.
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公开(公告)号：JP2002341643A
公开(公告)日：2002-11-29
申请号：JP2001148120
申请日：2001-05-17
Applicant: SHARP KK
Inventor： MUTO YOSHINORI , IWAMATSU TADASHI , HIRAKAWA HIROYUKI
Abstract: PROBLEM TO BE SOLVED: To provide an image forming device using conductive developer having various merits that development faithful to an electrostatic latent image and excellent image formation without fogging are realized, the device is made endurable to environmental fluctuation, the reduction of cost is attained, and a full color image in a vivid color is outputted by stabilizing the electrification characteristic of the developer. SOLUTION: By adjusting the surface roughness of an insulating layer or a high resistance layer provided on the surface of a developer carrier 11, the non-magnetic conductive developer 16 is carried nearly in an isolated state (discontinuous state) on the developer carrier 11. Then, the developer 16 is carried in a one-layer state in a direction perpendicular to the surface of the developer carrier 11. Thus, a phenomenon that the developer is developed also at a part (non-image part) other than the electrostatic latent image formed on the surface of an electrostatic latent image carrier 10 is prevented to restrain the occurrence of the fogging. The conductive developer is previously electrified to a polarity by which Coulomb's force works in the direction of the electrostatic latent image carrier at the part (image part) of the electrostatic latent image and brought into contact with the electrostatic latent image carrier in a developing area, whereby sufficient developing electric field is obtained and the image formation excellent in resolution is realized.
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