US 5,444,525 A · Image forming apparatus with image recording timing control

Abstract

The image forming apparatus can retain a stable and high image quality for many hours without use of any high precise mechanical parts and without causing any non-uniformity and mal-registration in a color image. In the image forming apparatus, an image recording medium (photosensitive drum) (6a) is driven by a rotative driving mechanism (pulleys and belts) (40a); and an image recording section (print bar) (6c) records an image repeatedly on the rotating image recording medium (6a) in a direction perpendicular to a rotational direction of the image recording medium. The image recorded on the image recording medium (6a) is transcribed onto an image transcribing medium (paper) (22) being fed in the rotational direction of the image recording medium (6a) to form an image. In particular, the apparatus comprises a rotation detecting section (rotary encoder) (6r) for detecting angular travel rates of the image recording medium (6a); and a recording timing control section (5) for controlling recording timing (HSYNC) at which the image is started to be recorded in the direction perpendicular to the rotational direction of the image recording medium (6a), on the basis of the angular travel rates detected by the rotation detecting section (6r).

Claims20

Dependent claims

An image forming apparatus for forming an image by recording image information and transcribing the recorded image information on an image transcribing medium, which comprises:

an image recording medium for recording the image information;
a rotational driving mechanism for rotating said image recording medium;
image recording means for recording an image repeatedly on said rotating image recording medium in a direction roughly perpendicular to a rotational direction of said image recording medium;
rotation detecting means for detecting angular travel rates of said image recording medium;
and
recording timing control means for controlling recording timing at which the image is started to be recorded in the direction perpendicular to the rotational direction of said image recording medium, on the basis of the angular travel rates detected by said rotation detecting means, wherein
said image recording means includes optical beam scanning and recording means for rotating a rotary polygonal mirror to scan an optical beam in the direction roughly perpendicular to the rotational direction of said image recording medium and for recording an image on said image recording medium by turning on and off the optical beam;
and
said recording timing control means includes scanning speed control means for controlling a scanning speed of the optical beam on the basis of the angular travel rates detected by said rotation detecting means. 58

6 more elements

An image forming apparatus for forming an image by recording image information and transcribing the recorded image information on an image transcribing medium, which comprises:

an image recording medium for recording the image information;
a rotational driving mechanism for driving said image recording medium;
image recording means for recording an image repeatedly on said rotating image recording medium in a direction perpendicular to a rotational direction of said image recording medium;
rotation detecting means for detecting angular travel rates of said image recording medium;
recording timing control means for controlling recording timing at which the image is started to be recorded in the direction perpendicular to the rotational direction of said image recording medium;
memory means for previously storing fluctuations in angular travel rates of said image recording medium;
calculating means for calculating predicted mal-register rates at a transfer position at which the image recorded on said image recording medium is transcribed onto the image transcribing medium, on the basis of the fluctuations in the angular travel rates stored in said memory means;
and
correcting means for correcting the recording timing on the basis of the calculated mal-register rates at the transfer position.

6 more elements

An image forming apparatus for forming a color image by recording image information and transcribing the recorded image information on an image transcribing medium, which comprises:

a plurality of image forming units arranged in a feed direction of the image transcribing medium, each of said image forming units including:
an image recording medium for recording the image information;
a rotational driving mechanism for rotating said image recording medium;
image recording means for recording an image repeatedly on said rotating image recording medium in a direction roughly perpendicular to a rotational direction of said image recording medium;
rotation detecting means for detecting angular travel rates of said image recording medium;
and
recording timing control means for controlling recording timing at which the image is started to be recorded in the direction perpendicular to the rotational direction of said image recording medium, on the basis of the angular travel rates detected by said rotation detecting means, wherein
said image recording means includes optical beam scanning and recording means for rotating a rotary polygonal mirror to scan an optical beam in the direction roughly perpendicular to the rotational direction of said image recording medium and for recording an image on said image recording medium by turning on and off the optical beam;
and
said recording timing control means includes scanning speed control means for controlling a scanning speed of the optical beam on the basis of the angular travel rates detected by said rotation detecting means.

7 more elements

A color image forming apparatus for forming a color image by recording image information and transcribing the recorded image information on an image transcribing medium, which comprises:

a plurality of image forming units arranged in a feed direction of the image transcribing medium, each of said image forming units including:
an image recording medium for recording the image information;
a rotational driving mechanism for driving said image recording medium;
image recording means for recording an image repeatedly on said rotating image recording medium in a direction perpendicular to a rotational direction of said image recording medium;
and
rotation detecting means for detecting angular travel rates of said image recording medium;
and
recording timing control means for controlling recording timing at which the image is started to be recorded in the direction perpendicular to the rotational direction of said image recording medium;
memory means for previously storing fluctuations in angular travel rates of said image recording medium;
calculating means for calculating predicted mal-register rates at a transfer position at which the image recorded on said image recording medium is transcribed onto the image transcribing medium, on the basis of the fluctuations in the angular travel rates stored in said memory means;
and
correcting means for correcting the recording timing on the basis of the calculated mal-register rates at the transfer position.

9 more elements

Dependencies are inferred from the claim text.

Image forming apparatus with image recording timing control

Life of this patent

Image forming apparatus with image recording timing control

Life of this patent

Abstract

Claims20