Light scanning apparatus, image forming apparatus equipped with such light scanning apparatus, and control method or image forming method for such image forming apparatus

A control method for an image forming apparatus comprising:

• a latent image carrier whose surface includes an effective image region spanning across a predetermined width in a main scanning direction and is driven in a sub scanning direction approximately orthogonal to the main scanning direction;
• and a latent image former which has a light source and a deflection mirror oscillating, and deflects a light beam from the light source using the deflection mirror so as to scan the effective image region with the deflected light beam, the method comprising:
• executing a single-side scanning mode in which the light beam is scanned only in a first direction included in the main scanning direction;
• executing a double-side scanning mode in which the light beam is scanned in both the first direction and a second direction opposite to the first direction;
• and
• switching selectively between the single-side scanning mode and the double-side scanning mode, wherein
• a condition to form latent images on the latent image carrier in the single-side scanning mode is different from a condition to form latent images on the latent image carrier in the double-side scanning mode,
• a width of the light beam on the effective scanning region is equal to or wider than a scanning pitch in the sub scanning direction in the single-side scanning mode, and
• an amount of light beam in the double-scanning mode is set to be smaller than an amount of light beam in the single-side scanning mode.

A control method for an image forming apparatus comprising:

• a latent image carrier whose surface includes an effective image region spanning across a predetermined width in a main scanning direction and is driven in a sub scanning direction approximately orthogonal to the main scanning direction;
• and a latent image former which has a light source and a deflection mirror oscillating, and deflects a light beam from the light source using the deflection mirror so as to scan the effective image region with the deflected light beam, the method comprising:
• executing a single-side scanning mode in which the light beam is scanned only in a first direction included in the main scanning direction;
• executing a double-side scanning mode in which the light beam is scanned in both the first direction and a second direction opposite to the first direction;
• and
• switching selectively between the single-side scanning mode and the double-side scanning mode, wherein
• a condition to form latent images on the latent image carrier in the single-side scanning mode is different from a condition to form latent images on the latent image carrier in the double-side scanning mode,
• halftoning to realize a tone reproduction, as the condition to form latent images, is altered between the single-side scanning mode and the double-side scanning mode,
• halftoning uses a line screen, and
• an angle between lines of the line screen and the sub scanning direction in the double-side scanning mode is smaller than in the single-side scanning mode.

A control method for an image forming apparatus comprising:

• a latent image carrier whose surface includes an effective image region spanning across a predetermined width in a main scanning direction and is driven in a sub scanning direction approximately orthogonal to the main scanning direction;
• and a latent image former which has a light source and a deflection mirror oscillating, and deflects a light beam from the light source using the deflection mirror so as to scan the effective image region with the deflected light beam, the method comprising:
• executing a single-side scanning mode in which the light beam is scanned only in a first direction included in the main scanning direction;
• executing a double-side scanning mode in which the light beam is scanned in both the first direction and a second direction opposite to the first direction;
• and
• switching selectively between the single-side scanning mode and the double-side scanning mode, wherein
• a condition to form latent images on the latent image carrier in the single-side scanning mode is different from a condition to form latent images on the latent image carrier in the double-side scanning mode,
• halftoning to realize a tone reproduction, as the condition to form latent images, is altered between the single-side scanning mode and the double-side scanning mode,
• halftoning uses a halftone screen which grows halftone dots in accordance with a tone level, the halftone dots being spaced apart in a first arrangement direction and a second arrangement direction, and
• an angle between the sub scanning direction and the first arrangement direction or the second arrangement direction, whichever forms a greater angle with the sub scanning direction, is smaller in the double-side scanning mode than in the single-side scanning mode.

An image forming apparatus comprising:

• a latent image carrier whose surface includes an effective image region spanning across a predetermined width in a main scanning direction and is driven in a sub scanning direction approximately orthogonal to the main scanning direction;
• a latent image former which has a light source and a deflection mirror oscillating, and deflects a light beam from the light source using the deflection mirror so as to scan the effective image region with the deflected light beam;
• and
• a scanning mode controller which switches selectively between a single-side scanning mode and a double-side scanning mode, the single-side scanning mode being a mode in which the light beam is scanned only in a first direction included in the main scanning direction, the double-side scanning mode being a mode in which the light beam is scanned in both the first direction and a second direction opposite to the first direction, wherein
• a condition to form latent images on the latent image carrier in the single side scanning mode is different from a condition to form latent images on the latent image carrier in the double-side scanning mode,
• halftoning to realize a tone reproduction, as the condition to form latent images, is altered between the single-side scanning mode and the double-side scanning mode,
• halftoning uses a line screen, and
• an angle between lines of the line screen and the sub scanning direction in the double-side scanning mode is smaller than in the single-side scanning mode.

An image forming apparatus comprising:

• a latent image carrier whose surface includes an effective image region spanning across a predetermined width in a main scanning direction and is driven in a sub scanning direction approximately orthogonal to the main scanning direction;
• a latent image former which has a light source and a deflection mirror oscillating, and deflects a light beam from the light source using the deflection mirror so as to scan the effective image region with the deflected light beam;
• and
• a scanning mode controller which switches selectively between a single-side scanning mode and a double-side scanning mode, the single-side scanning mode being a mode in which the light beam is scanned only in a first direction included in the main scanning direction, the double-side scanning mode being a mode in which the light beam is scanned in both the first direction and a second direction opposite to the first direction, wherein
• a condition to form latent images on the latent image carrier in the single-side scanning mode is different from a condition to form latent images on the latent image carrier in the double-side scanning mode,
• halftoning to realize a tone reproduction, as the condition to form latent images, is altered between the single-side scanning mode and the double-side scanning mode,
• halftoning uses a halftone screen which grows halftone dots in accordance with a tone level, the halftone dots being spaced apart in a first arrangement direction and a second arrangement direction, and
• an angle between the sub scanning direction and the first arrangement direction or the second arrangement direction, whichever forms a greater angle with the sub scanning direction, is smaller in the double-side scanning mode than in the single-side scanning mode.

A control method for an image forming apparatus comprising:

• a latent image carrier whose surface includes an effective image region spanning across a predetermined width in a main scanning direction and is driven in a sub scanning direction approximately orthogonal to the main scanning direction;
• and a latent image former which has a light source and a deflection mirror oscillating, and deflects a light beam from the light source using the deflection mirror so as to scan the effective image region with the deflected light beam, the method comprising:
• executing a single-side scanning mode in which the light beam is scanned only in a first direction included in the main scanning direction;
• executing a double-side scanning mode in which the light beam is scanned in both the first direction and a second direction opposite to the first direction;
• switching selectively between the single-side scanning mode and the double-side scanning mode;
• identifying a tone reproduction characteristic of the apparatus in the single-side scanning mode by detecting densities of toner images as tonal patch images, the toner images being formed by developing latent images which are formed in single-side scanning mode;
• and
• identifying a tone reproduction characteristic of the apparatus in the double-side scanning mode by detecting densities of toner images as tonal patch images, the toner images being formed by developing latent images which are formed in double-side scanning mode, wherein
• a condition to form latent images on the latent image carrier in the single-side scanning mode is different from a condition to form latent images on the latent image carrier in the double-side scanning mode, and
• in the case of toner images being formed in the single-side scanning mode, the toner images are formed based on the tone reproduction characteristic in the single-side scanning mode, whereas in the case of toner images being formed in the double-side scanning mode, the toner images are formed based on the tone reproduction characteristic in the double-side scanning mode.

An image forming apparatus comprising:

• a latent image carrier whose surface includes an effective image region spanning across a predetermined width in a main scanning direction and is driven in a sub scanning direction approximately orthogonal to the main scanning direction;
• a latent image former which has a light source and a deflection mirror oscillating, and deflects a light beam from the light source using the deflection mirror so as to scan the effective image region with the deflected light beam;
• a scanning mode controller which switches selectively between a single-side scanning mode and a double-side scanning mode, the single-side scanning mode being a mode in which the light beam is scanned only in a first direction included in the main scanning direction, the double-side scanning mode being a mode in which the light beam is scanned in both the first direction and a second direction opposite to the first direction;
• a developer which develops latent images formed on the surface of the latent image carrier in order to form toner images;
• a single-side characteristic identifier which identifies a tone reproduction characteristic of the apparatus in the single-side scanning mode by detecting densities of toner images as tonal patch images, the toner images being formed by developing latent images which are formed in single-side scanning mode;
• and
• a double-side characteristic identifier which identifies a tone reproduction characteristic of the apparatus in the double-side scanning mode by detecting densities of toner images as tonal patch images, the toner images being formed by developing latent images which are formed in double-side scanning mode, wherein
• a condition to form latent images on the latent image carrier in the single-side scanning mode is different from a condition to form latent images on the latent image carrier in the double-side scanning mode, and
• in the case of toner images being formed in the single-side scanning mode, the toner images are formed based on the tone reproduction characteristic in the single-side scanning mode, whereas in the case of toner images being formed in the double-side scanning mode, the toner images are formed based on the tone reproduction characteristic in the double-side scanning mode.