US 8,269,811 B2Granted

Image forming apparatus that controls an exposure amount to expose an image bearing member so that an electric intensity for forming a first image formed of an equal or smaller number of consecutive dots than a predetermined number in a predetermined direction is higher than an electric intensity for forming a second image formed of a larger number of consecutive dots than the predetermined number

AssigneeCanon Kabushiki Kaisha

InventorTakahiro Nakase

Life of this patent

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Abstract

In an image forming apparatus, an exposure device performs exposure on a non-image area of image pattern, performs an exposure on the image area in an exposure amount lower than the non-image area or does not perform exposure, and an exposure amount control device controls, with respect to pixels having the same density data, an exposure amount given by an exposure device to be smaller in a first portion, which is a thin-line of a width that is equal to or less than a predetermined number of pixels or which is an isolated dot of widths that are equal to or less than the predetermined number of pixels in two directions substantially orthogonal to each other, than in a second portion which is a line of a width exceeding the predetermined number or a surface of widths that exceed the predetermined number in two directions substantially orthogonal to each other.

Claims5

Dependent claims

An image forming apparatus for forming a toner image on a photosensitive member, the image forming apparatus comprising:

an image forming unit comprising an exposure unit configured to form an electrostatic latent image by exposing the photosensitive member and a development unit configured to develop the electrostatic latent image with toner, wherein a first portion on the photosensitive member exposed by the exposure unit is not developed with the toner, and a second portion on the photosensitive member is developed with the toner, and the second portion is either not exposed by the exposure unit or exposed in an exposure amount smaller than an exposure amount for the first portion;
a determination unit configured to determine whether the toner image formed in the second portion is a first image in which a number of dots equal to or smaller than a predetermined number are continuously formed in a predetermined direction or a second image in which a number of dots larger than the predetermined number are continuously formed in the predetermined direction;
and
a control unit configured to control the exposure unit so that an exposure amount in which the exposure unit exposes the photosensitive member for forming the second image is larger than an exposure amount in which the exposure unit exposes the photosensitive member for forming the first image and so that an exposure amount in which the exposure unit exposes the photosensitive member for forming the second image is smaller than an exposure amount in which the exposure unit exposes the first portion.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 13/033,506Filed 23 Feb 2011 · continuation
Priority: JP 2007-32137212 Dec 2007
Published: US 2011/0142464 A116 Jun 2011
Granted: 18 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G03G 15/326
In which the charge pattern is formed dotwise, e.g. by a thermal head: by application of light, e.g. using a LED array
G03G 15/0435
With means for controlling illumination or exposure: by introducing an optical element in the optical path, e.g. a filter
G03G 2215/0404
Exposure devices: laser
G03G 2215/0429
Arrangements for exposing and producing an image: changing or enhancing the image

Family

Application12/331,314Parent of this continuation · filed 9 Dec 2008
US 2011/0142464 A1Pre-grant publication · published 16 Jun 2011
US 7,920,157 B2Parent of this continuation
US 2009/0154946 A1Published application
US 8,269,811 B2This patent

From the US filing history. Foreign family members aren’t listed.