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US 7,068,957 B2Granted
Image forming apparatus and image forming method involving application of a developing bias to a toner carrier
AssigneeSeiko Epson Corporation
InventorsHidetsugu Shimura, Takashi Hama
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Abstract
Optimization of a density control factor accompanying formation of a patch image is executed every time a predetermined period of time elapses since the end of a preceding image forming operation. Since an image is formed at regular intervals in this manner, it is possible to suppress a density variation which is created as toner carried on a developer roller is left unused for long. This effect further improves when the developer roller is rotated idle prior to formation of a patch image or regularly at predetermined timing.
Claims28
An image forming apparatus comprising:
- an image carrier which is structured to carry an electrostatic latent image on a surface of said image carrier;
- a toner carrier which rotates in a predetermined direction while carrying toner and transports said toner to an opposed position facing said image carrier;
- an image forming means which applies a predetermined developing bias upon said toner carrier, causes said toner carried by said toner carrier to move to said image carrier, visualizes said electrostatic latent image with said toner, and forms a toner image;
- and
- a timer which measures an elapsed period since an end of formation of a toner image by said image forming means,
- wherein an image forming operation for forming a toner image corresponding to an image formation request upon receipt of said image formation request by a user, and an optimization for forming a toner image as a patch image, are selectively executed to detect a density of said patch image and to optimize a density control factor influencing an image density based on the result of the detection to control an image density,
- wherein if said image formation request is not newly received after said elapsed period, measured by said timer, has reached a first predetermined period, said optimization is executed, and
- wherein if said image formation request is newly received when said elapsed period is shorter than said first predetermined period but is equal to or longer than a second predetermined period which is shorter than said first predetermined period, said image forming operation in response to said image formation request is executed after executing said optimization.
5 more elements
An image forming method comprising:
- forming an electrostatic latent image on a surface of an image carrier in response to an image formation request from a user;
- and
- applying a predetermined developing bias upon a toner carrier which rotates while carrying toner on a surface of said toner carrier, to thereby move said toner carried by said toner carrier to said image carrier, visualize said electrostatic latent image with toner and form a toner image,
- wherein if said image formation request is not newly received after an elapsed period since an end of formation of a previous toner image, by an image forming means, has reached a first predetermined period, optimization is executed which includes forming the toner image as a patch image, to detect a density of said patch image and to optimize a density control factor influencing an image density based on the result of the detection to control an image density,
- and wherein if said image formation request is newly received when said elapsed period is shorter than said first predetermined period but is equal to or longer than a second predetermined period which is shorter than said first predetermined period, said image forming operation in response to said image formation request is executed after executing said optimization.
2 more elements
An image forming apparatus comprising:
- an image carrier which is structured to carry an electrostatic latent image on a surface of said image carrier;
- a toner carrier which rotates in a predetermined direction while carrying toner and transports said toner to an opposed position facing said image carrier;
- and
- image forming means which applies a predetermined developing bias upon said toner carrier, causes said toner carried by said toner carrier move to said image carrier, visualizes said electrostatic latent image with said toner, and forms a toner image,
- wherein in the event that said formation request is not newly received after an elapsed period, since an end of formation of a previous toner image, has reached a fourth predetermined period, idling of said toner carrier is executed which includes rotating said toner carrier at least one round,
- and wherein in the event that said image formation request is not newly received even after said fourth predetermined period from the end of said idling, said idling is executed once again.
3 more elements
An image forming apparatus comprising:
- an image carrier which is structured to carry an electrostatic latent image on a surface of said image carrier;
- a toner carrier which rotates in a predetermined direction while carrying toner and transports said toner to an opposed position facing said image carrier;
- and
- image forming means which applies a predetermined developing bias upon said toner carrier, causes said toner carried by said toner carrier move to said image carrier, visualizes said electrostatic latent image with said toner, and forms a toner image,
- wherein in the event that said image formation request is not newly received after an elapsed period, since an end of formation of a previous toner image, has reached a fourth predetermined period, idling of said toner carrier is executed which includes rotating said toner carrier at least one round,
- and wherein when said elapsed period reaches a fifth predetermined period which is longer than said fourth predetermined period, said idling is executed, a toner image is formed as a patch image, a density of said patch image is detected, and a density control factor influencing an image density is optimized based on the result of the detection.
3 more elements
An image forming apparatus comprising:
- an image carrier which is structured to carry an electrostatic latent image on a surface of said image carrier;
- a toner carrier which rotates in a predetermined direction while carrying toner and transports said toner to an opposed position facing said image carrier;
- and
- image forming means which applies a predetermined developing bias upon said toner carrier, causes said toner carried by said toner carrier move to said image carrier, visualizes said electrostatic latent image with said toner, and forms a toner image,
- wherein an image forming operation is executed which includes forming the toner image corresponding to an image formation request upon receipt of said image formation request by a user, and
- in the event that said image formation request is newly received when an elapsed period, since an end of formation of a previous toner image, is equal to or longer than a sixth predetermined period, and before executing said image forming operation in response to said image formation request, idling of said toner carrier is executed which includes rotating said toner carrier at least one round.
3 more elements
An image forming method comprising:
- forming an electrostatic latent image on a surface of an image carrier, and
- applying a predetermined developing bias upon a toner carrier which rotates in a predetermined direction while carrying toner on a surface of said toner carrier, to thereby move said toner carried by said toner carrier to said image carrier, visualize said electrostatic latent image with toner and form a toner image,
- wherein in the event that said image formation request is not newly received after an elapsed period, since an end of formation of a previous toner image, has reached a fourth determined period, idling of said toner carrier is executed which includes rotating said toner carrier at least one round,
- and wherein in the event that said image formation request is not newly received even after said fourth predetermined period from the end of said idling, said idling is executed once again.
1 more element
An image forming method comprising:
- forming an electrostatic latent image on a surface of an image carrier;
- and
- applying a predetermined developing bias upon a toner carrier which rotates in a predetermined direction while carrying toner on a surface of said toner carrier, to thereby move said toner carried by said toner carrier to said image carrier, visualize said electrostatic latent image with toner and form a toner image,
- wherein in the event that said image formation request is not newly received after an elapsed period, since an end of formation of a previous toner image, has reached a fourth predetermined period, idling of said toner carrier is executed which includes rotating said toner carrier at least one round,
- and wherein when said elapsed period reaches a fifth predetermined period which is longer than said fourth predetermined period, said idling is executed, a toner image is formed as a patch image, a density of said patch image is detected, and a density control factor influencing an image density is optimized based on the result of the detection.
2 more elements
An image forming method comprising:
- forming an electrostatic latent image on a surface of an image carrier in response to an image formation request from a user;
- and
- applying a predetermined developing bias upon a toner carrier which rotates in a predetermined direction while carrying toner on a surface of said toner carrier, to thereby move said toner carried by said toner carrier to said image carrier, visualize said electrostatic latent image with toner and form a toner image,
- wherein in the event that said image formation request is newly received when an elapsed period, since an end of formation of a previous toner image, is equal to or longer than a sixth predetermined period, and before forming the toner image in response to said image formation request, idling of said toner carrier is executed which includes rotating said toner carrier at least one round.
1 more element
Dependencies are inferred from the claim text.