Image recording apparatus and image recording method

An image recording apparatus usable with a rotationally-driven image carrier and a photosensitive drum, said image recording apparatus comprising:

• position signal output means for outputting a position signal when the image carrier is at a predetermined rotational position and, in response to the output position signal, starting each of a plurality of color component image formations using each of a plurality of color components, respectively;
• scanning means for scanning the photosensitive drum with a light beam modulated in accordance with an image signal;
• beam detection signal generating means for generating a beam detection signal upon detection of the light beam at a predetermined position, so as to regulate a timing of the light beam modulation for each line of scan;
• image transferring/superposing means for sequentially transferring and superposing on the image carrier a plurality of color component images formed on the photosensitive drum;
• measuring means for measuring a time difference between the position signal and the beam detection signal for each of the plurality of color component images;
• control means for controlling at least the rotation of the image carrier based on the time difference measured by said measuring means;
• developing means provided for each of the plurality of color components;
• and
• moving means for bringing said developing means for the color component to be formed to a developing position,
• wherein said moving means commences, before the transfer of a color component image to the image carrier, the movement of said developing means for a subsequent color component image towards the developing position.

An image recording apparatus usable with a rotationally-driven image carrier and a photosensitive drum, said image recording apparatus comprising:

• position signal output means for outputting a position signal when the image carrier is at a predetermined rotational position and, in response to the output position signal, starting each of a plurality of color component image formations using each of a plurality of color components, respectively;
• scanning means for scanning the photosensitive drum with a light beam modulated in accordance with an image signal;
• beam detection signal generating means for generating a beam detection signal upon detection of the light beam at a predetermined position, so as to regulate a timing of the light beam modulation for each line of scan;
• image transferring/superposing means for sequentially transferring and superposing on the image carrier a plurality of color component images formed on the photosensitive drum;
• measuring means for measuring a time difference between the position signal and the beam detection signal for each of the plurality of color component images;
• and
• control means for controlling, based on the time difference measured by said measuring means, a position of the light beam in a direction that crosses a scanning direction of said scanning means,
• wherein said control means comprises one of means for controlling a position of a light beam generating means and means for controlling a position of a mirror for reflecting the light beam.

An image recording apparatus for forming a color image by superposing frame images of a plurality of colors, comprising:

• forming means for making a light beam in accordance with an image signal reflected by a rotating rotational polyhedric mirror, scanning on a predetermined photosensitive member with said light beam, and forming a frame image on said photosensitive member;
• superposing means for transferring a plurality of frame images formed by said forming means on a moving predetermined image bearing member and superposing said plurality of frame images;
• first generating means for generating a first synchronizing signal indicating a state of rotation for said rotational polyhedric mirror;
• second generating means for generating a second synchronizing signal indicating that said image bearing member has moved to a predetermined position;
• and
• rotation velocity control means for varying a moving velocity of said image bearing member in accordance with a phase difference between said first and second synchronizing signals.

An image recording method for forming a color image by superposing frame images of a plurality of colors, comprising the steps of:

• forming step for making a light beam in accordance with an image signal reflected by a rotating rotational polyhedric mirror, scanning on a predetermined photosensitive member with said light beam, and forming a frame image on said photosensitive member;
• superposing step for transferring a plurality of frame images formed in said forming step on a moving predetermined image bearing member and superposing said plurality of frame images;
• first generating step for generating a first synchronizing signal indicating a state of rotation of said rotational polyhedric mirror;
• second generating step for generating a second synchronizing signal indicating that said image bearing member has moved to a predetermined position;
• and
• rotation velocity control step for varying a moving velocity of said image bearing member in accordance with a phase difference between said first and second synchronizing signals.

An image recording apparatus for forming a color image by superposing frame images of a plurality of colors, comprising:

• forming means for making a light beam in accordance with an image signal reflected by a rotational polyhedric mirror, scanning on a predetermined photosensitive member, and forming a frame image on said photosensitive member;
• superposing means for transferring a plurality of frame images formed by said forming means on a predetermined image bearing member to move by the velocity based on a first control clock and superposing said plurality of frame images;
• first generating means for generating a first synchronizing signal indicating a timing of rotation of said rotational polyhedric mirror;
• second generating means for generating a second synchronizing signal indicating that said image bearing member has moved to a predetermined position;
• third generating means for generating pulses of the number indicating a phase difference between said first and second synchronizing signals;
• and
• switching means for switching a first control clock for deciding a velocity of said image bearing member in accordance with the number of said pulses to a second control clock.

An image recording method for forming a color image by superposing frame images of a plurality of colors, comprising the steps of:

• forming step for making a light beam in accordance with an image signal reflected by a rotational polyhedric mirror, scanning on a predetermined photosensitive member, and forming a frame image on said photosensitive member;
• superposing step for transferring a plurality of frame images formed on said forming step on a predetermined image bearing member to move by the velocity based on a first control clock and superposing said plurality of frame images;
• first generating step for generating a first synchronizing signal indicating a timing of rotation of said rotational polyhedric mirror;
• second generating step for generating a second synchronizing signal indicating that said image bearing member has moved to a predetermined position;
• third generating step for generating pulses of the number indicating a phase difference between said first and second synchronizing signals;
• and
• switching step for switching a first control clock for deciding velocity of said image bearing member in accordance with the number of said pulses to a second control clock.

An image recording apparatus for superposing a plurality of images having a plurality of lines and forming a color image on a moving image bearing member, comprising:

• first generating means for generating a first synchronizing signal indicating a timing of writing each of said plurality of lines;
• second generating means for generating a second synchronizing signal indicating that said image bearing member has moved to a predetermined position;
• and
• rotation velocity control means for varying moving velocity of said image bearing member in accordance with a phase difference between said first and second synchronizing signals.

An image recording method for superposing a plurality of images having a plurality of lines and forming a color image on a moving image bearing member, comprising the steps of:

• first generating step for generating a first synchronizing signal indicating a timing of writing each of said plurality of lines;
• second generating step for generating a second synchronizing signal indicating that said image bearing member has moved to a predetermined position;
• and
• rotation velocity control step for varying moving velocity of said image bearing member in accordance with a phase difference between said first and second synchronizing signals.

An image recording apparatus comprising:

• exposure means for exposing in the main scanning direction of an image bearing member;
• driving means for driving said image bearing member in a sub scanning direction;
• first detection means for detecting a predetermined position of said image bearing member;
• second detection means for detecting an exposure position of said exposure means;
• generation means for generating a driving clock signal to control driving said image bearing member;
• and
• control means for controlling the driving clock signal generated by said generation means in accordance with an amount of mis-registration between the predetermined position detected by said first detection means and the exposure position detected by said second detection means,
• wherein said driving means drives said image bearing member on the basis of the driving clock signal controlled by said control means.

An image recording apparatus comprising:

• exposure means for exposing in a main scanning direction of an image bearing member;
• driving means for driving said image bearing member in a sub scanning direction;
• first detection means for detecting a predetermined position of said image bearing member;
• second detection means for detecting an exposure position of said exposure means;
• clock generation means capable of generating a first clock signal and a second clock signal to control driving said image bearing member;
• and
• control means for driving said image bearing member by selectively using the first clock signal and the second clock signal in accordance with an amount of mis-registration between the predetermined position detected by said first detection means and the exposure position detected by said second detection means.

An image recording apparatus comprising:

• exposure means for exposing in a main scanning direction of an image bearing member;
• driving means for driving said image bearing member in a sub scanning direction;
• first detection means for detecting a predetermined position of said image bearing member;
• second detection means for detecting an exposure position of said exposure means;
• clock generation means capable of generating a first clock signal and a second clock signal to control driving said image bearing member;
• and
• control means for driving said image bearing member by selectively using the first clock signal and the second clock signal in accordance with an amount of mis-registration between the predetermined position detected said first detection means and the exposure position detected by said second detection means,
• wherein selection of a clock by said control means is performed during a predetermined compensation period before forming an image.