Electrophotography – Diagnostics – Unit or part identification
Reexamination Certificate
2003-01-23
2004-12-07
Grainger, Quana (Department: 2852)
Electrophotography
Diagnostics
Unit or part identification
C399S027000
Reexamination Certificate
active
06829443
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of Korean Application No. 2002-32524, filed Jun. 11, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of detecting toner depletion in an image forming apparatus, and more particularly, to a method of detecting toner depletion in an image forming apparatus having an improved structure, in which toner low and toner depletion states are detected without using an additional detection sensor.
2. Description of the Related Art
In general, image forming apparatuses using toner form an electrostatic latent image corresponding to a desired image by scanning light on a photosensitive body, develop the electrostatic latent image by supplying toner to the electrostatic latent image from a developing unit in which toner is received, transfer the developed electrostatic latent image onto paper, and fuse the transferred electrostatic latent image on the paper, thereby forming an image.
In such image forming apparatuses, it is possible to detect whether toner that is received in the developing unit is exhausted and to inform a user of the toner depletion, and the concentration of a developer needs to be properly adjusted so as to improve the efficiency of the developer.
FIG. 1
illustrates a conventional apparatus to detect the amount of toner remaining in a developing unit. As shown in
FIG. 1
, a sensing unit
120
is formed in a lower portion of a developing unit
100
and has an uneven shape, and transparent windows
121
are placed on the right and left sides of the sensing unit
120
, respectively. A detection sensor
130
, outside the developing unit
100
, includes a light emitting unit
131
and a light receiving unit
132
. The transparent windows
121
are placed between the light emitting unit
131
and the light receiving unit
132
.
In addition, an agitator
110
, having a shaft
111
and a wing
112
, is installed in the developing unit
100
. The agitator
110
distributes toner uniformly while rotating in the developing unit
100
, and rubs and charges the toner to prepare for image development.
If the wing
112
passes through the sensing unit
120
while the agitator
110
rotates in the developing unit
100
, the toner adhered to the transparent windows
121
is cleaned, and then, the toner is pushed into the sensing unit
120
. This is done to prevent sensing errors, which may be caused by toner adhered to the transparent windows
121
by static electricity and moisture. Such errors cause the sending unit
120
to detect toner even when toner does not remain in the developing unit
100
.
Because of the above structure, light emitted from the light emitting unit
131
passes through the toner of the sensing unit
120
and is detected by the light receiving unit
132
. In this case, the amount of light detected by the light receiving unit
132
depends on the amount of the toner remaining in the sensing unit
120
. Hence, after the relation between the amount of light detected by the light receiving unit
132
and the amount of toner remaining in the sensing unit
120
is experimentally obtained, the amount of toner remaining in the developing unit
100
can be calculated using the experimental result.
However, the conventional apparatus to detect the amount of toner remaining in the developing unit
100
shown in
FIG. 1
detects the amount of toner remaining only in a partial region of the developing unit
100
, i.e., only in the sensing unit
120
. Thus, the conventional apparatus shown in
FIG. 1
determines that the toner is exhausted and displays a toner depletion message if toner does not remain in the sensing unit
120
, even when toner remains in another region of the developing unit
100
. Hence, a user cannot rely on the toner depletion message. Also, an additional detection sensor
130
should be provided, and thus overall costs of the apparatus increase.
In addition, even though the agitator
110
cleans the transparent windows
121
while rotating in the developing unit
100
, when an image forming apparatus does not perform a print operation and is in a print standby state for a long time, or when the image forming apparatus is turned off for a long time and thus toner adheres to the transparent windows
121
, the agitator
110
may not completely clean the transparent windows
121
. In this case, although toner is completely exhausted, it may be determined by the detection sensor
130
that toner remains in the sensing unit
120
.
In another method of detecting toner depletion in an image forming apparatus, the number of pixels printed from an initial time when the developing unit is used is counted without using the detection sensor shown in
FIG. 1
, and a toner depletion message is displayed if the number of pixels reaches a predetermined value. This method can be used only if the amount of toner required to print one pixel is uniform. However, the amount of toner that is actually used varies according to the concentration of an image printed even when the same number of pixels is printed. Thus, in the above method, the accuracy of detecting toner depletion is poor.
SUMMARY OF THE INVENTION
Accordingly, it is an aspect of the present invention to provide a method of detecting toner depletion in an image forming apparatus, in which a toner low state or a toner depletion state is detected by counting the number of pixels of a printed image without using an additional detection sensor, and by periodically detecting the concentration of the printed image.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing, and/or other aspects may be achieved by providing a method of detecting toner depletion in an image forming apparatus which includes a photosensitive medium, a laser scanning unit to scan light on the photosensitive medium and to form an electrostatic latent image thereon, a developing unit to supply toner to the electrostatic latent image and thereby form a toner image, and an image controller to control the forming of the toner image. The method includes comparing an accumulation pixel number Qt obtained by accumulating and counting a number of pixels of the formed image with a reference pixel number Qr, calculated from an amount of toner initially received by the developing unit, and recognizing that the image forming apparatus is in a toner low state if the accumulation pixel number Qt is larger than the reference pixel number Qr, comparing a concentration of the formed image with a reference concentration Dr and detecting a toner depletion state if it is recognized that the image forming apparatus is in the toner low state; determining whether the developing unit is reinstalled; and determining whether the developing unit is a new developing unit, if it is determined that the developing unit is reinstalled.
The reference pixel number Qr may be set to be smaller than a quotient obtained by dividing the amount of toner that is initially received in the developing unit by the amount of toner required to print one pixel.
The method may further include detecting whether the amount of toner received in the developing unit is in a toner low state or a toner depletion state, if the image forming apparatus is turned on. The detecting includes checking a toner depletion state variable TE stored in the image controller and detecting whether the image forming apparatus is in the toner depletion state, and checking a toner low state variable TL stored in the image controller, and detecting whether the image forming apparatus is in the toner low state.
The comparing of the concentration may include forming a test patch to measure the concentration of the formed image printed per a predetermined print number Pr
1
; detecting the image concentration Di from the test pa
Byun Seung-young
Shim Woo-jung
Grainger Quana
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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