US 8,477,171 B2Granted

Image forming apparatus with selective application of light source

AssigneeBrother Kogyo Kabushiki Kaisha

InventorIsao Kubo

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Abstract

An image forming apparatus includes: a light source; a light-source driving unit; a photosensitive member including an image forming region; a determining unit determining a level of a rotation speed of the photosensitive member; a scanner unit exposing the photosensitive member by deflecting the light beam from the light source by a deflecting unit; a sensor receiving the light beam and outputs a detection signal; and a control unit controlling the image forming apparatus based on the detection signal output from the sensor. When the determining unit determines that the rotation speed is low, the light-source driving unit is configured to drive the light source to emit the light beam when a deflecting direction of the light beam is oriented toward the sensor and not to drive the light source to emit the light beam when the deflecting direction of the light beam is oriented toward the image forming region.

Claims16

Dependent claims

An image forming apparatus comprising:

a light source configured to emit a light beam;
a light-source driving unit configured to drive the light source;
a photosensitive member that comprises an image forming region;
a determining unit configured to determine a level of a rotation speed of the photosensitive member;
a scanner unit configured to expose the photosensitive member by deflecting the light beam emitted from the light source by a deflecting unit;
a sensor configured to receive the light beam and output a detection signal;
and
a control unit configured to control the image forming apparatus based on the detection signal output from the sensor,
wherein when the determining unit determines that the rotation speed is low, the light-source driving unit is configured:
to drive the light source to emit the light beam when a deflecting direction of the light beam is oriented toward the sensor;
and
not to drive the light source to emit the light beam when the deflecting direction of the light beam is oriented toward the image forming region,
wherein an intensity of the light beam emitted from the light source is configured to vary according to a current supplied to the light source,
wherein the light-source driving unit is configured to supply:
a first current configured to drive the light source to emit a light beam having a first intensity for exposing the photosensitive member with an intensity of greater than or equal to a predetermined exposure amount;
and
a second current configured to drive the light source to emit a light having a second intensity for exposing the photosensitive member with an intensity of less than the predetermined exposure amount,
wherein when the deflecting direction of the light beam is oriented toward the sensor, the light-source driving unit is configured to supply the first current to the light source,
wherein when the determining unit determines that the rotation speed of the photosensitive member is high, the light-source driving unit is configured to constantly supply the second current as a bias current to the light-source driving unit, and
wherein when the determining unit determines that the rotation speed of the photosensitive member is low, the light-source driving unit is configured to stop supplying the bias current to the light source and to make a timing at which the light source is supplied with the first current faster than a timing at which the first current is supplied when the rotation speed of the photosensitive member is high.

17 more elements

An image forming apparatus comprising:

a light source configured to emit a light beam;
a light-source driving unit configured to drive the light source;
a photosensitive member that comprises an image forming region;
a determining unit configured to determine a level of a rotation speed of the photosensitive member;
a scanner unit configured to expose the photosensitive member by deflecting the light beam emitted from the light source by a deflecting unit;
a sensor configured to receive the light beam and output a detection signal;
and
a control unit configured to control the image forming apparatus based on the detection signal output from the sensor,
wherein when the determining unit determines that the rotation speed is low, the light-source driving unit is configured:
to drive the light source to emit the light beam when a deflecting direction of the light beam is oriented toward the sensor;
and
not to drive the light source to emit the light beam when the deflecting direction of the light beam is oriented toward the image forming region,
wherein an intensity of the light beam emitted from the light source is configured to vary according to a current supplied to the light source,
wherein the light-source driving unit is configured to supply:
a first current configured to drive the light source to emit a light beam having a first intensity for exposing the photosensitive member with an intensity of greater than or equal to a predetermined exposure amount;
and
a second current configured to drive the light source to emit a light having a second intensity for exposing the photosensitive member with an intensity of less than the predetermined exposure amount,
wherein when the deflecting direction of the light beam is oriented toward the sensor, the light-source driving unit is configured to supply the first current to the light source,
wherein when the determining unit determines that the rotation speed of the photosensitive member is high, the light-source driving unit is configured to constantly supply the second current as a bias current to the light-source driving unit, and
wherein when the determining unit determines that the rotation speed of the photosensitive member is low, the light-source driving unit is configured to stop supplying the bias current to the light source and to adjust a value of the first current supplied to the light source to substantially the same value as the first current supplied to the light source when the rotation speed of the photosensitive member is determined to be high.

17 more elements

An image forming apparatus comprising:

a light source configured to emit a light beam;
a light-source driving unit configured to drive the light source;
a photosensitive member that comprises an image forming region;
a determining unit configured to determine a level of a rotation speed of the photosensitive member;
a scanner unit configured to expose the photosensitive member by deflecting the light beam emitted from the light source by a deflecting unit;
a sensor configured to receive the light beam and output a detection signal;
and
a control unit configured to control the image forming apparatus based on the detection signal output from the sensor,
wherein when the determining unit determines that the rotation speed is low, the light-source driving unit is configured:
to drive the light source to emit the light beam when a deflecting direction of the light beam is oriented toward the sensor;
and
not to drive the light source to emit the light beam when the deflecting direction of the light beam is oriented toward the image forming region,
wherein an intensity of the light beam emitted from the light source is configured to vary according to a current supplied to the light source,
wherein the light-source driving unit is configured to supply:
a first current configured to drive the light source to emit a light beam having a first intensity for exposing the photosensitive member with an intensity of greater than or equal to a predetermined exposure amount;
and
a second current configured to drive the light source to emit a light having a second intensity for exposing the photosensitive member with an intensity of less than the predetermined exposure amount,
wherein when the deflecting direction of the light beam is oriented toward the sensor, the light-source driving unit is configured to supply the first current to the light source,
wherein when the determining unit determines that the rotation speed of the photosensitive member is high, the light-source driving unit is configured to constantly supply the second current as a bias current to the light-source driving unit, and
wherein when the determining unit determines that the rotation speed of the photosensitive member is low, the light-source driving unit is configured to stop supplying the bias current to the light source and to adjust a value of the first current supplied to the light source to a value less than that of the first current supplied to the light source when the rotation speed of the photosensitive member is determined to be high.

17 more elements

An image forming apparatus comprising:

a light source configured to emit a light beam;
a light-source driving unit configured to drive the light source;
a photosensitive member that comprises an image forming region;
a determining unit configured to determine a level of a rotation speed of the photosensitive member;
a scanner unit configured to expose the photosensitive member by deflecting the light beam emitted from the light source by a deflecting unit;
a sensor configured to receive the light beam and output a detection signal;
and
a control unit configured to control the image forming apparatus based on the detection signal output from the sensor,
wherein when the determining unit determines that the rotation speed is low, the light-source driving unit is configured:
to drive the light source to emit the light beam when a deflecting direction of the light beam is oriented toward the sensor;
and
not to drive the light source to emit the light beam when the deflecting direction of the light beam is oriented toward the image forming region,
wherein an intensity of the light beam emitted from the light source is configured to vary according to a current supplied to the light source,
wherein the light-source driving unit is configured to supply:
a first current configured to drive the light source to emit a light beam having a first intensity for exposing the photosensitive member with an intensity of greater than or equal to a predetermined exposure amount;
and
a second current configured to drive the light source to emit a light having a second intensity for exposing the photosensitive member with an intensity of less than the predetermined exposure amount,
wherein when the deflecting direction of the light beam is oriented toward the sensor, the light-source driving unit is configured to supply the first current to the light source,
wherein when the determining unit determines that the rotation speed of the photosensitive member is high, the light-source driving unit is configured to constantly supply the second current as a bias current to the light-source driving unit, and
wherein when the determining unit determines that the rotation speed of the photosensitive member is low, the light-source driving unit is configured:
not to supply the bias current when the deflecting direction of the light beam is oriented toward the image forming region;
and
to supply the bias current when the deflecting direction of the light beam is oriented toward the sensor.

20 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/715,378Filed 1 Mar 2010
Priority: JP 2009-0483042 Mar 2009
Published: US 2010/0220368 A12 Sep 2010
Granted: 2 Jul 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H04N 1/0473
Detection, control or error compensation of scanning velocity or position: in subscanning direction, e.g. picture start or line-to-line…
H04N 1/053
Detection, control or error compensation of scanning velocity or position: in main scanning direction, e.g. synchronisation of line start or…
H04N 2201/0082
Types of the still picture apparatus: image hardcopy reproducer
H04N
Pictorial communication