Electrophotography – Diagnostics – Consumable
Reexamination Certificate
2000-10-13
2003-04-08
Grainger, Quana M. (Department: 2852)
Electrophotography
Diagnostics
Consumable
C399S012000
Reexamination Certificate
active
06546212
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus and a unit detachably attachable (mountable) to the image forming apparatus, and also relates to an information displaying system related to a “unit detachably attachable to the image forming apparatus”.
2. Related Background Art
Conventionally, in an image forming apparatus such as a copier and a laser beam printer, for example, the image forming apparatus of an electrophotography system, an image is formed on a recording medium by a latent image formed by projecting light, which corresponds to an image information, on an electrophotographically photosensitive body, a developer (including a toner) is supplied to the latent image by using developing means for making a visualized image, and the image is transferred from the photosensitive body to the recording medium.
In such image forming apparatus, for the purpose of replacing such consumable items as the electrophotographically photosensitive body and a developer and making maintenance convenient, there is a process-cartridge system, in which the electrophotographically photosensitive body is assembled with developing means, charging (electrifying) means, cleaning means, and also a storage part of the developer and a container of a waste developer, which are processing means acting on the electrophotographically photosensitive body, as a process cartridge to make it detachably attachable to a main body of the image forming apparatus. According to the process cartridge system, maintenance of the apparatus can be carried out by a user himself or herself, and not by a service person to make considerable improvement of operability possible. Therefore, the process cartridge system is widely applied to the electrophotographic image forming apparatus.
Meanwhile, for instance, in a color image forming apparatus having developing means for a plurality of colors, in the case where the degree of consumption of the different developing means differs from each other and in the case where the degree, i.e., life, of consumption of the electrophotographic photosensitive body differs from that of the developing means, the developing means for respective colors or the electrophotographic photosensitive body is allowed individual replacement and maintenance by, for example, individually making a cartridge of a developing cartridge for respective colors, in which the developing means and a developer containing section are assembled as the cartridge, and a photosensitive body drum cartridge, in which the cleaning means and the container of the waste developer and the electrophotographically photosensitive body are assembled integrally to make the cartridge.
In the image forming apparatus of the cartridge detachably attachable system as described above, in the case where the developer is exhausted and the electrophotographic photosensitive body falls down, the user can obtain a good image output again by replacing the cartridge.
Conventionally, such cartridge has an expiration date, within which a high quality image can be obtained, after manufacture of the cartridge. This is because by temporal change since the day of manufacture of the cartridge, deterioration, which is exemplified by a decrease in image density, loss of evenness of a halftone image, and the occurrence of a fog, of the quality of the output image is caused by reasons such as a change of sensitivity of the electrophotographic photosensitive body, a change of the modulus of elasticity of a member made by using an elastic body, and the change of resistance of the developer.
When the cartridge is started to be used, the cartridge is taken out from a sealed packing member and a developer seal, which seals the developer within the storage part of the developer, is removed allowing outer ambient conditions to influence the cartridge, e.g., taking up of moisture by the developer. Therefore, the quality of the removed cartridge is lowered slightly faster than a packed cartridge. Thus, it is preferable that the expiration date before which a high quality image can be obtained after the cartridge has been started to be used, is set separately from the expiration date after manufacture of the cartridge, as described above.
The expiration date after manufacture and the expiration date after start of use of the cartridge are conventionally generally described on the outside of a package of the cartridge or the instructions for use. Reading the description, the user can know information about the expiration date of the cartridge including the expiration date after manufacture of the cartridge or the expiration date after start of use of the cartridge.
However, when the cartridge is taken out from the package and used by mounting on the main body of the image forming apparatus, the user loses information about the expiration date of the cartridge, such as the expiration date after manufacture of the cartridge or the expiration date after start of the use.
In the case where the cartridge is used after the expiration date after manufacture of the cartridge or the expiration date after the start of use, as described above, though it very slowly occurs, deterioration of the output quality occurs, exemplified by a decrease in image density. Therefore, it is preferable that the cartridge is used before the expiration date. However, when the cartridge is used for a long period, the cartridge may be occasionally used after the expiration date after manufacture of the cartridge or the expiration date after the start of use.
In such cases, conventionally, information about the expiration date of the cartridge including the expiration date after manufacture or the expiration date after the start of use of the cartridge becomes difficult, because the manufacture date and the starting date of use of the cartridge are unknown.
In addition, in the image forming apparatus of the cartridge detachably attachable system as described above, in the case where the developer is exhausted and the electrophotographic photosensitive body falls down, the user can obtain a good image output again by replacing the cartridge. However, cartridge replacement should be carried out by the user and therefore, detection of deterioration, which is exemplified by consumption of the developer and removal of the electrophotographic photosensitive body, of the cartridge is performed.
In methods for detection of the degree of deterioration of the cartridge, for example, there are methods of detecting the degree of deterioration of the electrophotographic photosensitive body (the photosensitive body drum) made in a cylindrical shape:
a method of counting the number of sheets printed,
a method of counting the rotation of the photosensitive body drum,
a method of measuring current running in the photosensitive body drum, and
a method of measuring the rotation time of the photosensitive body drum and the application time of an electrification bias to estimate the degree of deterioration of the photosensitive body drum by conversion system.
Further, there are methods of detecting the degree of consumption of the developer:
an image dot count method of counting image dots which make up an image on the electrophotographic photosensitive body and converting the image dot composition to the quantity of the developer used,
a torque detection method of detecting the torque of means for agitating the developer in the developer containing section, and
a static capacity detection method in which a flat antenna substrate comprising an electrode pattern having a pair of conductive portions, which is formed in parallel with a certain distance from each other, is arranged in a position which is the position of a internal side surface of the developer containing section, contacting with developer, and where an area of contact with the developer, according to a reduction of the quantity of the developer changes and the change of the static capacity detectable by the flat antenna substrate according to reduction of the quantity of the develop
Ogata Hiroaki
Sasame Hiroshi
Yamamoto Shinya
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Grainger Quana M.
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