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US 5,315,351 AGranted
Image forming apparatus
AssigneeMinolta Camera Kabushiki Kaisha
InventorsMoriyoshi Matsushiro, Naoki Toyoshi, Tsugihito Yoshiyama
Life of this patent
Estimating the term…
Abstract
An image forming apparatus in which a light amount of an irradiation lamp for exposure or voltage value of a developing bias applied to a developing electrode is adjusted based upon density value of test toner images formed on the surface of the photosensitive member for preventing the occurrence of toner fogging.
Claims26
An image forming apparatus comprising:
- discharging means for discharging an electric charge on a surface of a photosensitive member upon test image formation;
- developing means for forming a toner image on the surface of the photosensitive member with a toner, said developing means includes a developing electrode to which at least two kinds of biases having different voltages and a same polarity as a toner charge polarity are applied upon test image formation, so that at least two test toner images having different densities are formed on the surface of the photosensitive member that has been discharged by said discharging means;
- detecting means for detecting the density of each of the test toner images;
- and
- control means for controlling the voltage value of a developing bias to be applied to the developing electrode during normal image formation based on the detected values of the test toner images.
2 more elements
An image forming apparatus comprising:
- charging means for charging a surface of a photosensitive member;
- exposure means for exposing the charged surface of the photosensitive member with an image of an original to form an electrostatic latent image on the surface of the photosensitive member;
- discharging means for discharging the electric charge on the surface of the photosensitive member when the exposure means is not operated;
- developing means having a developing electrode for forming a toner image on the surface of the photosensitive member with a toner;
- applying means for applying to the developing electrode a first developing bias having a polarity opposite that of a toner charge polarity when the exposure means is operated and applying to the developing electrode a second developing bias having a polarity which is the same as that of the toner charge polarity when the exposure means is not operated, said second developing bias having a voltage which is applied on at least two levels so that at least two test toner images having different densities are formed on the surface of the photosensitive member;
- detecting means for detecting the density of each of the test toner images;
- and
- determining means for determining a voltage value of the first developing bias by use of the detected values of the test toner images.
5 more elements
In an image forming apparatus comprising a developing device having a developing electrode for developing, with a toner, an electrostatic latent image formed on a photosensitive member by image forming means, an image stabilization method that is performed when the electrostatic latent image is not formed on the photosensitive member, which comprises the following steps of:
- discharging an electric charge on a surface of the photosensitive member;
- applying a first developing bias having a polarity which is the same as a toner charge polarity to the developing electrode while changing a bias voltage on a least two levels, so that at least two test toner images having different densities are formed on the surface of the photosensitive member that is discharged by said discharging means;
- detecting the density of each of the test toner images;
- and
- controlling a voltage value of a second developing bias applied to the developing electrode when the electrostatic latent image is formed during image formation based on the detected values of the test toner images.
2 more elements
An image forming apparatus comprising:
- charging means for charging a surface of a photosensitive member at a predetermined potential;
- exposure means for exposing the charged surface of the photosensitive member with at least two different light amounts to form at least two test electrostatic latent images;
- a developing unit for developing said test electrostatic latent images with a developer accommodated therein to form test toner images;
- detecting means for detecting a density of each of the test toner images;
- calculating means for calculating a sensitivity characteristics value of the photosensitive member based on the detected values of the test toner images;
- storing means for storing a reference light amount of exposure and a reference sensitivity characteristics value of the photosensitive member;
- and
- control means for controlling the amount of exposure light based on the reference light amount and the sensitivity characteristics value of the photosensitive member respectively stored in said storing means, and the sensitivity characteristics value of the photosensitive member calculated by said calculating means.
5 more elements
A method performed in image forming apparatus, which comprises:
- charging a surface of a photosensitive member at a predetermined potential;
- exposing the charged surface of the photosensitive member with at least two different light amounts of form at least two test electrostatic latent images on the surface of the photosensitive member;
- developing said test electrostatic latent images to form test toner images with a toner;
- detecting a density of each of the test toner images;
- inputting a reference light amount and reference densities of the test toner images in a memory;
- and
- determining a suitable amount of exposure light based on the detected values of the test toner images, and the reference light amount and the reference densities of the test toner images respectively input in said memory.
4 more elements
An image forming apparatus comprising:
- charging means for charging a surface of a photosensitive member at a predetermined potential;
- original image forming means for forming an original electrostatic latent image by exposing the charged surface of the photosensitive member with an image light corresponding to the original;
- test image forming means for forming a test electrostatic latent image by exposing the charged surface of the photosensitive member with a predetermined light amount;
- a developing unit for developing said test electrostatic latent image with a developer accommodated therein to form a test toner image;
- first detecting means for detecting a density of the test toner image on the surface of the photosensitive member;
- second detecting means for detecting a density of the developer in the developing unit;
- first control means for controlling the image light amount based on the density of the test toner image;
- and
- second control means for controlling the density of the developer based on the value detected by the second detecting means.
6 more elements
Dependencies are inferred from the claim text.