Digital image forming apparatus which specifies a sensitivity characteristic of a photoconductor

Claim 2

An image forming apparatus for converting image data into light emission data, indicating the quantity of emission light based on γ correction data, to form an image based on the light emission data, said image forming apparatus comprising: image forming means for forming an image, said image forming means including: a photoconductor, charging means for charging said photoconductor, exposing means for exposing said photoconductor, charged by said charging means, to light modulated by the light emission data to form an electrostatic latent image on said photoconductor, and developing means for developing, with a developer material, the electrostatic latent image on said photoconductor formed by said exposing means; developer material detecting means for detecting the amount of the developer material adhering to the image on said photoconductor developed by said developing means; first specifying means for specifying a sensitivity characteristic of said photoconductor; second specifying means for specifying a development characteristic of said developing means based on the sensitivity characteristic specified by said first specifying means and the amount of adhering developer material detected by said developer material detecting means; deciding means for deciding an optimal operating condition of said image forming means based on the development characteristic of said developing means specified by said second specifying means; and calculating means for calculating γ correction data for obtaining a desired gradation characteristic under the operating condition decided by said deciding means.

Claim 3

The image forming apparatus according to claim 1, wherein: said first specifying means includes potential detecting means for detecting a surface potential of said photoconductor, and specifies the sensitivity characteristic of said photoconductor by controlling said exposing means to expose said photoconductor, charged by said charging means, to a plurality of different quantities of light and by controlling said potential detecting means to detect the surface potential of the exposed photoconductor and approximating a relationship between the surface potential of the exposed photoconductor and the quantity of exposure by a function based on the detection result obtained by said potential detecting means.

Claim 4

The image forming apparatus according to claim 2, wherein: said second specifying means specifies the development characteristic of the developing means by controlling said image forming means to prepare a plurality of test images different in density, by controlling said developer material detecting means to detect the amount of developer material adhering to the respective test image, and by calculating a potential of the respective test image by the sensitivity characteristic specified by said first specifying means, to approximate a relationship between a development potential, which is the difference between the surface potential of said photoconductor and a development bias potential, and the amount of adhering developer material by development based on the detected amount of the developer material adhering to the respective test image and the calculated potential of the respective test image.

Claim 5

The image forming apparatus according to claim 3, wherein: said deciding means calculates the development potential, at which a predetermined target amount of adhering developer material is obtained based on the specified development characteristic, and calculates a charge potential and a development bias potential at which the calculated development potential is obtained based on the specified sensitivity characteristic of said photoconductor, to decide the calculated charge potential and development bias potential as an operating condition of said image forming means.

Claim 6

The image forming apparatus according to claim 1, further comprising: determining means for comparing the sensitivity characteristic specified by said first specifying means with a predetermined characteristic to determine whether the specified sensitivity characteristic is regular or irregular based on the comparison result.

Claim 7

The image forming apparatus according to claim 5, further comprising: means for, when said determining means determines that the specified sensitivity characteristic is irregular, employing said predetermined characteristic instead of the specified sensitivity characteristic.

Claim 8

The image forming apparatus according to claim 5, wherein: said first specifying means specifies the sensitivity characteristic in a predetermined period, and said determining means determines that the specified sensitivity characteristic is irregular by comparing the specified sensitivity characteristic with one specified in the previous period.

Claim 9

The image forming apparatus according to claim 5, further comprising: warning means for warning the user of irregularity when said determining means determines that the specified sensitivity characteristic is irregular.

Claim 10

The image forming apparatus according to claim 1, further comprising: determining means for comparing the development characteristic specified by said second specifying means with a predetermined characteristic to determine whether the specified development characteristic is regular or irregular based on the comparison result.

Claim 11

The image forming apparatus according to claim 9, further comprising: means for, when said determining means determines that the specified development characteristic is irregular, employing said predetermined characteristic instead of the specified development characteristic.

Claim 12

The image forming apparatus according to claim 9, wherein: said second specifying means specifies the development characteristic in a predetermined period, and said determining means determines that the specified development characteristic is irregular by comparing the specified development characteristic with one specified in the previous period.

Claim 13

The image forming apparatus according to claim 9, further comprising: warning means for warning the user of irregularity when said determining means determines that the specified development characteristic is irregular.

Claim 14

The image forming apparatus according to claim 1, further comprising: reset means for resetting to an initial value at least one of the sensitivity characteristic specified by said first specifying means and the development characteristic specified by said second specifying means.

Claim 15

The image forming apparatus according to claim 13, wherein: said reset means is started up in response to a manual keying operation.

Claim 16

The image forming apparatus according to claim 13, wherein: said reset means is started up in response to an exchange of parts of the image forming apparatus.

Claim 17

The image forming apparatus according to claim 15, wherein: said reset means includes means for detecting an exchange of another photoconductor for said photoconductor.

Claim 18

The image forming apparatus according to claim 15, wherein: said reset means includes means for detecting an exchange of another developing means for said developing means.

Claim 19

The image forming apparatus according to claim 15, wherein: said reset means includes means for detecting an exchange of another developer material detecting means for said developer material detecting means.

Claim 20

The image forming apparatus according to claim 1, wherein: said exposing means is modulated in first and second modes different in emission ratio, and said calculating means calculates respective γ correction data for said first and second modes.

Claim 21

An image forming apparatus for forming an image under a set image forming condition, said image forming apparatus comprising: image forming means for forming an image, said image forming means including: a mobile photoconductor, charging means for charging said photoconductor, exposing means for exposing said photoconductor, charged by said charging means, to light modulated by light emission data to form an electrostatic latent image on said photoconductor, and developing means for developing, with a developer material, the electrostatic latent image on said photoconductor formed by said exposing means; potential detecting means for detecting a potential of said photoconductor at a predetermined detection position; first specifying means for specifying a sensitivity characteristic of said photoconductor at said detection position based on the potential of said photoconductor detected by said potential detecting means; second specifying means for specifying the sensitivity characteristic of said photoconductor at a development position of said developing means based on the sensitivity characteristic of said photoconductor specified by said first specifying means; and setting means for determining and setting an image forming condition based on the sensitivity characteristic specified by said second specifying means.

Claim 22

An image forming apparatus for forming an image under a set image forming condition, said image forming apparatus comprising: image forming means for forming an image, said image forming means including: a mobile photoconductor, charging means for charging said photoconductor, exposing means for exposing said photoconductor, charged by said charging means, to light modulated by light emission data to form an electrostatic latent image on said photoconductor, and developing means for developing, with a developer material, the electrostatic latent image on said photoconductor formed by said exposing means; potential detecting means for detecting a potential of said photoconductor at a predetermined detection position; first specifying means for specifying a sensitivity characteristic of said photoconductor at said detection position based on the potential of said photoconductor detected by said potential detecting means; second specifying means for specifying the sensitivity characteristic of said photoconductor at a development position of said developing means based on the sensitivity characteristic of said photoconductor specified by said first specifying means; and setting means for determining and setting an image forming condition based on the sensitivity characteristic specified by said second specifying means.

Claim 23

The image forming apparatus according to claim 20, wherein: said image forming condition includes a charge potential of said charging means and a development bias potential of said developing means.

Claim 24

The image forming apparatus according to claim 20, wherein: said first specifying means specifies the sensitivity characteristic of said photoconductor by controlling said exposing means to expose said photoconductor, charged by said charging means, to a plurality of different quantities of light and by controlling said potential detecting means to detect a surface potential of the exposed photoconductor to approximate a relationship between the surface potential of the exposed photoconductor and the quantity of exposure by a function based on the detection result obtained by said potential detecting means.

Claim 25

The image forming apparatus according to claim 22, wherein: said second specifying means specifies the sensitivity characteristic at the development position by a function obtained by correcting a coefficient of the function, based on the detection result obtained by said potential detecting means, according to the development position.

Claim 26

The image forming apparatus according to claim 23, wherein: said second specifying means includes means for detecting a using condition of the image forming apparatus, and corrects the sensitivity characteristic at the development position according to the detected using condition.

Claim 27

The image forming apparatus according to claim 24, wherein: said using condition includes an ambient temperature.

Claim 28

The image forming apparatus according to claim 20, wherein: said photoconductor is mobile in a plurality of modes different in moving speed, and said second specifying means specifies the sensitivity characteristic at the development position according to the moving speed of said photoconductor.

Claim 29

An image forming apparatus for forming an image under a set image forming condition, said image forming apparatus comprising: image forming means for forming an image, said image forming means including: a photoconductor, charging means for charging said photoconductor, exposing means for exposing said photoconductor, charged by said charging means, to light modulated by light emission data to form an electrostatic latent image on said photoconductor, and developing means for developing, with a developer material, the electrostatic latent image on said photoconductor formed by said exposing means; developer material detecting means for detecting the amount of developer material adhering to the image on said photoconductor developed by said developing means; specifying means for specifying a sensitivity characteristic of said photoconductor; deciding means for controlling said image forming means to form a test image, for controlling said developer material detecting means to detect the amount of developer material adhering to the test image, and for calculating a surface potential of the test image based on the sensitivity characteristic specified by said specifying means to decide the surface potential of said photoconductor at which development by said developing means is started based on the detected adhering amount and the calculated surface potential; and setting means for setting an image forming condition based on the surface potential decided by said deciding means.

Claim 30

An image forming apparatus for forming an image under a set image forming condition, said image forming apparatus comprising: image forming means for forming an image, said image forming means including: a photoconductor, charging means for charging said photoconductor, exposing means for exposing said photoconductor, charged by said charging means, to light modulated by light emission data to form an electrostatic latent image on said photoconductor, and developing means for developing, with a developer material, the electrostatic latent image on said photoconductor formed by said exposing means; developer material detecting means for detecting the amount of developer material adhering to the image on said photoconductor developed by said developing means; specifying means for specifying a sensitivity characteristic of said photoconductor; deciding means for controlling said image forming means to form a test image, for controlling said developer material detecting means to detect the amount of developer material adhering to the test image, and for calculating a surface potential of the test image based on the sensitivity characteristic specified by said specifying means to decide the surface potential of said photoconductor at which development by said developing means is started based on the detected adhering amount and the calculated surface potential; and setting means for setting an image forming condition based on the surface potential decided by said deciding means.

Claim 31

The image forming apparatus according to claim 27, wherein: said set image forming condition includes a charge potential of said charging means and a development bias potential of said developing means.

Claim 32

The image forming apparatus according to claim 27, wherein: said specifying means includes potential detecting means for detecting the surface potential of said photoconductor, and specifies the sensitivity characteristic of said photoconductor by controlling said exposing means to expose said photoconductor, charged by said charging means, to a plurality of different quantities of light and by controlling said potential detecting means to detect the surface potential of the exposed photoconductor to approximate a relationship between the surface potential of the exposed photoconductor and the quantity of exposure by a function based on the detection result obtained by said potential detecting means.

Claim 33

The image forming apparatus according to claim 28, further comprising: adjusting means for adjusting the surface potential of said photoconductor at which said development is started manually.

Claim 34

An image forming apparatus for converting image data into light emission data, indicating the quantity of light emission based on γ correction data, to form an image based on the light emission data, said image forming apparatus comprising: image forming means for forming an image, said image forming means including: a photoconductor, charging means for charging said photoconductor, exposing means for exposing said photoconductor, charged by said charging means, to light modulated by the light emission data to form an electrostatic latent image on said photoconductor, developing means for developing, with a developer material, the electrostatic latent image on said photoconductor formed by said exposing means, and transferring means for transferring the image developed by said developing means onto a transfer material; developer material detecting means for detecting the amount of developer material adhering to the image on said photoconductor developed by said developing means; first specifying means for specifying a sensitivity characteristic of said photoconductor; second specifying means for specifying a development characteristic of said developing means based on the sensitivity characteristic specified by said first specifying means and the adhering amount of developer material detected by said developer material detecting means; third specifying means for specifying a transfer characteristic of said transferring means; deciding means for deciding an optimal operating condition of said image forming means based on the development characteristic of said developing means specified by said second specifying means and the transfer characteristic specified by said third specifying means; and calculating means for calculating γ correction data for obtaining a desired gradation characteristic under the operating condition decided by said deciding means.

Claim 35

An image forming apparatus for converting image data into light emission data, indicating the quantity of light emission based on γ correction data, to form an image based on the light emission data, said image forming apparatus comprising: image forming means for forming an image, said image forming means including: a photoconductor, charging means for charging said photoconductor, exposing means for exposing said photoconductor, charged by said charging means, to light modulated by the light emission data to form an electrostatic latent image on said photoconductor, developing means for developing, with a developer material, the electrostatic latent image on said photoconductor formed by said exposing means, and transferring means for transferring the image developed by said developing means onto a transfer material; developer material detecting means for detecting the amount of developer material adhering to the image on said photoconductor developed by said developing means; first specifying means for specifying a sensitivity characteristic of said photoconductor; second specifying means for specifying a development characteristic of said developing means based on the sensitivity characteristic specified by said first specifying means and the adhering amount of developer material detected by said developer material detecting means; third specifying means for specifying a transfer characteristic of said transferring means; deciding means for deciding an optimal operating condition of said image forming means based on the development characteristic of said developing means specified by said second specifying means and the transfer characteristic specified by said third specifying means; and calculating means for calculating γ correction data for obtaining a desired gradation characteristic under the operating condition decided by said deciding means.

Claim 36

The image forming apparatus according to claim 31, wherein: said first specifying means includes potential detecting means for detecting a surface potential of said photoconductor, and specifies the sensitivity characteristic of said photoconductor by controlling said exposing means to expose said photoconductor, charged by said charging means, to a plurality of different quantities of light and by controlling said potential detecting means to detect the surface potential of the exposed photoconductor to approximate a relationship between the surface potential of the exposed photoconductor and the amount of exposure by a function based on the detection result obtained by said potential detecting means.

Claim 37

The image forming apparatus according to claim 32, wherein: said second specifying means specifies the development characteristic of the developing means by controlling said image forming means to form a plurality of test images different in density, by controlling said developer material detecting means to detect the amount of developer material adhering to the respective test image, and by calculating a potential of the respective test image by the sensitivity characteristic specified by said first specifying means to approximate a relationship between a development potential, which is the difference between the potential of said photoconductor and a development bias potential, and the amount of developer material adhering by development by a function based on the amount of developer material adhering to the respective test image and the calculated potential of the respective test image.

Claim 38

The image forming apparatus according to claim 33, wherein: said deciding means calculates, based on the specified transfer characteristic, the amount of adhering developer material on said photoconductor with which a predetermined target density is obtained on a transfer material, calculates a development potential at which the calculated amount of adhering developer material is obtained, and calculates a charge potential and the development bias potential at which the calculated development potential is obtained based on the specified sensitivity characteristic of said photoconductor, to decide the calculated charge potential and the development bias potential as an operating condition of said image forming means.

Claim 39

The image forming apparatus according to claim 31, wherein: said third specifying means has a memory storing a transfer efficiency.

Claim 40

The image forming apparatus according to claim 35, wherein: said memory further stores correction data for correcting the transfer efficiency according to a using condition.

Claim 41

The image forming apparatus according to claim 36, wherein: said correction data includes data on an ambient temperature.

Claim 42

The image forming apparatus according to claim 36, wherein: said correction data includes data on the kind of transfer materials.

Claim 43

The image forming apparatus according to claim 36, wherein: said correction data includes data on the number of copies to be made by the apparatus.