Electrophotography – Diagnostics – Consumable
Reexamination Certificate
1999-09-30
2001-01-09
Chen, Sophia S. (Department: 2852)
Electrophotography
Diagnostics
Consumable
C399S064000, C399S254000
Reexamination Certificate
active
06173130
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a development-agent container for containing development agents in a development apparatus in an electrophotographic image forming apparatus, a process cartridge, and an image forming apparatus.
2. Related Background Art
In an image forming apparatus of an electrophotographic system, in other words, in an apparatus for obtaining images by developing with development agents, electrostatic latent images on an image carrier, such as a photosensitive drum or the like, it is required to supply development agents as expendables. As a method for supplying development agents, there are the following methods.
First of all, a development-agent receiving container is installed in an image forming apparatus body, such as a photocopier or the like, and a development-agent supplying container, filled with development agents in advance for supplying development agents, is prepared as another expendable, independent from the image forming apparatus, and when the development-agent receiving container comes to have the smaller remaining amount of the development agents, the development agents in the development-agent supplying container are supplied, as a supplying method, in the whole amount at once to the development-agent receiving container.
As another method, there is a method using a stationary container, in which, though a development-agent supplying container is prepared in the same way as the above method, after a development-agent supplying container is attached to the image forming apparatus body without supplying the agents in the whole amount, the development-agent supplying container is left over as it is in the image forming apparatus body, and the development agents are gradually delivered toward a development apparatus by operating a development-agent stirring apparatus until the development agents are used up.
In addition, there is a process cartridge method in which a photosensitive drum, a cleaning apparatus, and a development apparatus filled in advance with development agents, are formed unitedly and in which those elements are detachably attached to the image forming apparatus body. In this method, development agents are delivered gradually to a development sleeve and a photosensitive drum from a development-agent containing section formed in the cartridge by operating a development-agent stirring apparatus until the incorporated development agents are used up where the cartridge is attached once in the image forming apparatus body.
However, in all the methods, it is required to detect the remaining amount of the development agents in the development-agent container, and the remaining amount is detected by a light transmission method, an antenna method, and like.
FIG. 5
is an illustration of a development apparatus performing detection of the development-agent remaining amount through a light transmission method;
FIG. 6
is a diagram illustrating the relation between a toner-remaining amount and a light-transmission time. A development apparatus
100
shown in
FIG. 5
is structured of a development unit
107
in which a development sleeve
105
, a development agent supplying roller
106
, and so on are installed, and a development-agent container
104
welded thereto for containing the development agents. Light-transmission windows
101
,
102
for detecting the development-agent remaining amount are attached to the development-agent container
104
. A stirring member
103
is rotatively attached to the interior of the development-agent container
104
to stir the toners T serving as development agents, and is driven in an arrow AA direction by a drive means, not shown. The stirring member
103
is constituted of a stirring stay
103
a
connected to the drive means and a flexible stirring sheet
103
b
for removing the toners clinging to the light-transmission windows
101
,
102
.
In the image forming apparatus body, a light-emitting portion
108
and a light-receiving portion
109
are arranged, and the detection light L is emitted from the light emitting portion
108
, transmitted through the light transmission windows
101
,
102
, and received at the light-receiving portion
109
to detect the remaining amount of the development agents T in the development agent container
104
. More specifically, the detection light L is emitted for a period while the stirring member
103
rotates for one turn, and time t that light transmits in the development-agent container
104
is detected during this period. When this amount exceeds a prescribed threshold t
1
, it is judged as toners remain in a small amount, and the apparatus notifies it to the users.
With the development apparatus thus structured, though the stirring sheet
103
b
is structured to wipe the surfaces of the light-transmission windows
101
,
102
by a rotation of the stirring member
103
during the detection operation, the stirring sheet
103
b
is at a position shielding the detection light L from starting wiping the light-transmission window
101
to ending wiping the light-transmission window
102
. Although a flexible sheet, such as PET, is frequently used for a material of the stirring sheet, such a conventional sheet is generally transparent or semitransparent, which has low light-shielding property.
Where the toner-remaining amount is relatively large in the development-agent container
104
, toners clings to the surface of the stirring sheet
103
b
in a large amount, and when the stirring sheet
103
b
is on a beam axis of the detection light L, the stirring sheet
103
b
also shields the detection light L. However, if the toner-remaining amount become small, situations that the sheet can shield the light and cannot shield the light may occur, depending on the toner amount clinging to the stirring sheet
103
b
. In addition to the toner-clinging degree on the stirring sheet, situations that the sheet can shield the light and cannot shield the light may occur depending on differences in the light emitting of the detection light and sensitivity of the light receiving sensor.
FIG. 6
is a graph showing a relation between a toner amount in the development-agent container
104
and the transmission time t of the detection light. If the toner amount M is reduced, the transmission time t increases, and when the time t exceeds the threshold t
1
, the apparatus issues a warning of “empty of toner amount.” However, as described above, with the conventional structure, where the toner amount is small, the stirring sheet
103
b
may shield light in some case but may not shield light in other cases, and when the light is shielded, it becomes a curve as shown with numeral S
1
, whereas when the light is not shielded, it becomes a curve as shown with numeral S
2
. The toner-remaining amount M where the transmission time t exceeds the threshold t
1
is M
1
when the light is shielded and M
2
when the light is not shielded, and generates large differences.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a development-agent container, a process cartridge, and an image forming apparatus capable of detecting toner-remaining amounts stably and surely without being affected by toners clinging to a stirring sheet.
A representative structure of a development agent container according to the invention to accomplish the above object includes a development-agent containing unit for containing development agents for developing latent images formed on an image carrier; a light-transmission window formed at a frame of the development agent containing unit for detecting a remaining amount of the development agents in the development-agent containing unit; and a stirring member disposed in the development-agent containing unit for stirring the development agents, the stirring member having a light-shielding flexible sheet for rubbing the light-transmission window.
Where the flexible sheet is made of a synthetic resin sheet having flexibility, with a carbon coating thereon, the flexible sheet can be structured to have an adequate
Canon Kabushiki Kaisha
Chen Sophia S.
Fitzpatrick ,Cella, Harper & Scinto
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