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US 7,479,977 B2Granted
Image forming apparatus and laser scanning method thereof
AssigneeSamsung Electronics Co., Ltd.
InventorsBong-hwan Choi, Dong-hyup Shin
Life of this patent
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Abstract
An image forming apparatus is provided with a laser scanning unit having at least two laser diodes to form an electrostatic latent image on a photosensitive body with laser beams emitted from the laser diodes; an engine driving unit having at least one driving motor to drive a plurality of built-in units; and a control unit arranged to control one of the laser scanning unit and the engine driving unit so as to adjust a process speed of the engine driving unit or a scan speed of the laser scanning unit with a certain rate depending on a selected resolution in order to enhance a resolution of an image.
Claims18
An image forming apparatus, comprising:
- a laser scanning unit having at least two laser sources to emit laser beams to form an electrostatic latent image on a photosensitive body;
- an engine driving unit having at least one driving motor to drive a plurality of built-in units so as to form an image on a printable medium with a certain process speed;
- and
- a control unit arranged to control one of the laser scanning unit and the engine driving unit to change one of a process speed of the engine driving unit and a scan speed of the laser scanning unit with a certain rate depending on a resolution selected when the laser scanning unit forms the electrostatic latent image on the photosensitive body,
- wherein the resolution selected is a resolution corresponding to a magnification (K) of a preset value or for a basic resolution calculated with the following expression:
- K=2n+1 (wherein n is a natural number), and
- wherein the control unit controls the laser scanning unit such that laser beams containing image information are to be emitted from the laser diodes advancing by a correction distance (D) in an initial scan of an image, and laser beams containing image information are to be emitted from the laser diodes lagging by the correction distance (D) in a last scan of the image calculated with the following expression:
- D=d×(K−1)/2
- wherein d is an interval between scan lines and K is the magnification for the basic resolution corresponding to the selected resolution.
6 more elements
A laser scanning method of an image forming apparatus, comprising:
- determining a resolution selected;
- and
- forming an electrostatic latent image on a photosensitive body along scan lines in a sub scanning direction through at least two laser diodes, while controlling one of a process speed and a scan speed with a certain rate in accordance with the selected resolution,
- wherein the selected resolution is selected from an external source as a resolution corresponding to a magnification (K) of a preset value or for a basic resolution calculated with the following expression:
- K=2n +1(wherein n is a natural number), and
- wherein, during the formation of the electrostatic latent image, laser beams containing image information are to be emitted from the laser diodes advancing by a correction distance (D) in an initial scan of an image and laser beams containing image information are to be emitted from the laser diodes lagging by the correction distance (D) in a last scan of the image calculated with the following expression:
- D=d×(K−1)/2
- wherein d is an interval between scan lines and K is the magnification for the basic resolution corresponding to the selected resolution.
5 more elements
An image forming apparatus, comprising:
- a laser scanning unit having at least two laser diodes to scan laser beams onto a photosensitive body in accordance with a scan speed so as to form an electrostatic latent image thereon;
- an engine driving unit having at least one driving motor to drive internal units so as to form an image on a printable medium with a process speed;
- and
- a control unit arranged to determine a resolution selected and control one of the process speed and the scan speed with a certain rate in accordance with the selected resolution for forming the electrostatic latent image on a photosensitive body and subsequently the image on the printable medium,
- wherein the selected resolution is selected from an external source as a resolution corresponding to a magnification (K) of a preset value or a basic resolution calculated with the following expression:
- K=2n +1(wherein n is a natural number), and
- wherein, during the formation of the electrostatic latent image, the control unit controls the laser scanning unit such that laser beams containing image information are to be emitted from the laser diodes advancing by a correction distance (D) in an initial scan of an image and laser beams containing image information are to be emitted from the laser diodes lagging by the correction distance (D) in a last scan of the image calculated with the following expression:
- D=d×(K−1)/2
- wherein d is an interval between scan lines and K is the magnification for the basic resolution corresponding to the selected resolution.
6 more elements
Dependencies are inferred from the claim text.