Method and apparatus for indicating time for exchanging toner recovery container of electrographic apparatus

In order to provide an indication when it is necessary to exchange toner recovery container, an electrophotographic apparatus monitors the accumulated driving time of a toner supply drive unit, and a massage indicating "exchange the toner recovery container" is displayed at the time when a toner supply switch is operated under state in which the accumulated driving time exceeds a preset value.

BACKGROUND OF THE INVENTION 
The present invention relates to an electrophotographic apparatus and a 
notifying method of exchanging a toner recovery container for the 
electrophotographic apparatus. 
In an electrophotographic apparatus, almost all of a toner image formed on 
the surface of a photosensitive body is transferred onto a record member, 
such as a sheet of paper, in a transferring process. However, a small 
residual amount of toner is not transferred onto the record member and 
remains on the surface of the photosensitive body. Such residual toner is 
removed by a cleaning device and then recovered in a toner recovery 
container. 
In an electrophotographic apparatus of this kind, if the status of toner 
recovery in a toner recovery container is not monitored, the cleaning 
efficiency of the cleaning device is degraded and, accordingly, the 
residual toner is not sufficiently removed, thereby affecting the quality 
of printing. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a method and apparatus in 
an electrophotographic apparatus which are capable of properly indicating 
when it is time to exchange a toner recovery container. 
The above object of the present invention can be attained by a method of 
indicating when it is time to exchange a toner recovery container in an 
electrophotographic apparatus having a toner supply driving unit for 
transferring toner to a toner hopper unit, a toner supply switch for 
performing driving/stopping operation of said toner supply driving unit 
and a toner recovery container for recovering residual toner removed from 
a surface of a photosensitive body, the method comprising steps of 
monitoring the accumulated period of time of driving operation of said 
toner supply driving unit from the time when said toner recovery container 
is exchanged, and indicating a need for exchanging said toner recovery 
container if said accumulated period of driving operation exceeds a preset 
value. 
Further, the object of the present invention can be attained by an 
electrophotographic apparatus having a toner supply driving unit for 
transferring toner to a toner hopper unit, a toner supply switch for 
performing driving/stopping operation of said toner supply driving unit, 
and a toner recovery container for recovering residual toner removed from 
a surface of a photosensitive body, which apparatus comprises an 
accumulated driving period monitoring means for monitoring an accumulated 
period of time of driving operation of said toner supply driving unit from 
the time when said toner recovery container is exchanged, and a toner 
recovery container exchange notifying means for indicating a need for 
exchanging said toner recovery container if said accumulated period of 
driving operation exceeds a preset value. 
According to the present invention, it is possible to reliably indicate a 
need to exchange the toner recovery container at a proper time. According 
to another characteristic of the present invention, the burden on an 
operator of the apparatus can be reduced, since the notification of a need 
to recover the toner recovery container is performed only when the 
operator is present near the apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An embodiment of the present invention will be described in detail below 
with reference to the accompanying drawings. 
FIG. 1 is a schematic diagram showing the construction of an embodiment of 
an electrophotographic apparatus in accordance with the present invention. 
FIG. 2 is a perspective view showing the overall construction of an 
electrophotographic apparatus. 
Referring to the drawings, an electrophotographic apparatus 100 has a toner 
hopper 4, which is a container for storing toner 1 for printing, and a 
toner empty sensor 7. The toner empty sensor 7 detects a lack of toner 1 
in the toner hopper 4. When the toner 1 is supplied to the toner hopper 4, 
a toner bottle 2 filled with toner 1 is mounted onto a toner supply port 3 
to transfer the toner 1 to the toner hopper 4 through the toner supply 
port 3 using a toner supply drive unit 5. The toner supply drive unit 5 
starts to transfer toner when a toner supply switch 6 is actuated, and, 
after a certain time (SI) has elapsed, the motor is stopped. However, if 
the toner supply switch 6 is actuated again during operation of the drive 
unit 5, the drive unit 5 is stopped. 
A toner feed driving unit 8 transfers toner 1 from the toner hopper 4 to a 
developer 9. Developing agent 11 is formed by mixing the toner 1 and a 
carrier 10 is a certain proportion for friction-charging the toner 1. The 
developing agent 11 is transferred to a photosensitive drum 12 by a 
developing roll 13 mounted on the developer 9. 
The electrophotographic apparatus 100 starts to rotate the photosensitive 
drum 12 based on a printing operation starting signal received from a 
control system 22 (refer to FIG. 3). The photosensitive drum 12 is rotated 
with a speed corresponding to a printing speed, and continues to rotate 
until the printing operation is completed. As the photosensitive drum 12 
is started to rotate, a voltage is applied to a corona charger to 
uniformly charge the surface of the photosensitive drum 12, for example, 
with a positive charge. 
As character data and/or picture data converted into dot data is 
transmitted from the control system to the electrophotographic apparatus 
100 as ON/OFF signals of a laser beam, portions irradiated with the laser 
beam and portions not irradiated with the laser beam are formed on the 
surface of the photosensitive drum 12. When the portions where the charge 
on the photosensitive drum 12 disappears due to irradiation by the laser 
beam arrive at a position facing the developer 9, the toner 1, which is 
positively charged, is attracted by static electricity to form a toner 
image on the photosensitive drum 12. 
A sheet of paper 15 is transferred to a position between the photosensitive 
drum 12 and a transferring unit 14 from a paper hopper 21 by a tractor 22 
in synchronism with the timing of arrival of the print data formed on the 
photosensitive drum 12 at the transfer position. 
The toner image formed on the photosensitive drum 12 is attracted onto the 
paper 15 by the action of a transferring unit 14 for applying a charge 
having a polarity opposite to the toner image to the reverse side surface 
of the paper 15. 
The paper 15 arriving at the transferring unit 14 is heated by a 
pre-heater, and nipped and transferred by a nip unit composed of a pair of 
fixing rolls, including a heating roll 23 and a pressing roll 24, while 
being heated and pressed, and thereby the toner image is melt-fixed on the 
paper 15. The paper 15, which is transferred by the heating roll 24 and 
the pressing roll 23, is transferred to a stacker table 25 where it is 
stacked. 
Unnecessary toner remaining on the surface of drum 12 after passing through 
the image transferring position of the photosensitive drum 12 is scraped 
off by a cleaning brush 16 and is accumulated in a toner bag 18 after 
being sucked up with a blower 17 through a duct 20. The reference 
character 19 denotes a toner bag sensor which detects the time when the 
toner bag 18 is exchanged. 
FIG. 3 is a diagram showing the construction of a control system of an 
electrophotographic apparatus in accordance with the present invention. 
The control system is composed of a printer engine controller 30 and a 
controller 36. The printer engine controller 30 receives each of the 
outputs from the toner supply switch 6, the toner empty sensor 7 and the 
toner bag sensor 19. The printer engine controller has a toner supply 
accumulating time counter 32, which represents a means to monitor the 
accumulated time of use of the toner supply drive unit by measuring the 
periods during which a toner supply signal is at a high level. The 
controller 36, which is connected to the printer engine controller 30 
through an interface, has a display 38. Toner supply control in the first 
embodiment of an electrophotographic apparatus in accordance with the 
present invention will be described below with reference to the timing 
chart of FIG. 4. 
When a certain accumulated time elapses after a toner bag has been set, a 
massage indicating "exchange the toner bag" is displayed on the display 
unit 38 (406). When the toner bag 18 is exchanged in response to this 
display, an output (405) of the toner bag sensor 19 becomes low level (L) 
for a moment, and the accumulated time indicated by the time counter 32 in 
the printer engine controller 30 is reset to zero, so that it may restart 
its count (404). 
The signal of the toner supply switch 6 indicates a high level (H) when the 
toner supply switch is actuated and a low level (L) when the toner supply 
switch is released. When the toner supply switch 6 is actuated to supply 
toner after printing is started (401), a signal (402) of the toner supply 
switch 6 changes from high level to low level, and a toner supply signal 
(403) becomes high level to start toner supply. Toner supply is 
automatically stopped when a certain time SI elapses. Otherwise, toner 
supply can be stopped by actuating the toner supply switch 6 once again. 
The toner supply accumulating time counter 32 counts the time during which 
the toner supply signal (403) is in high level state, and monitors the 
accumulated time while comparing it to a preset value. When the toner 
supply switch is next actuated to start supplying toner after the 
accumulated time counter (404) reaches the preset value S2, the toner 
recovery container exchange signal (406) becomes high level, and a message 
indicating "exchange the toner recovery container" is displayed using the 
display unit 38. 
The message indicating "exchange the toner recovery container" is not 
displayed immediately after the accumulated time counter (404) reaches the 
preset value S2, but is displayed only when the toner supply switch is 
actuated the next time after the accumulated time counter (404) reaches 
the preset value S2. The reason for this is that, at the time when the 
toner supply switch is actuated, an operator is always present near the 
apparatus. Thereby, the message is easily noticed, and the burden on the 
operator can be reduced. 
FIG. 5 is a view showing an embodiment of a multicolor printer to which the 
present invention is applied. Four photosensitive drums 121-124 each 
performing respective color development processes, have developers 91-94, 
toner bottles 201-204, heating rolls 141-144 and cleaning brushes 161-164, 
respectively. A blower 17, a toner bag 18 and a toner bag sensor 19 are 
provided in common to the four drum arrangement. 
FIG. 6 is a timing chart showing operation of the apparatus of FIG. 5. In 
this embodiment, when a certain accumulated time elapses after a toner bag 
is set, a message indicating "exchange the toner bag" is displayed on a 
display unit 38 (413). When the toner bag 18 is exchanged based on this 
display, the output (412) of the toner bag set sensor 19 becomes low level 
(L) for a moment, and the accumulated time indicated by the time counter 
32 in the printer engine controller is reset to zero, so that it may 
restart its count (411). The toner supply accumulating time counter 32 
counts periods of time during which the toner supply signals (403, 405, 
407, 409) corresponding to operations of the toner supply switches (402, 
404, 406, 408) of the developers 91-94, respectively, are at a high level, 
and the accumulated time is monitored and compared with a preset value. 
When the toner supply switch is next actuated so as to start supplying 
toner after the accumulated time counter (411) reaches the preset value 
S2, the toner recovery container exchange signal (413) becomes high level, 
and the message indicating "exchange the toner recovery container" is 
displayed using the display unit 38. 
According to the present invention, it is possible to indicate a need to 
exchange the toner recovery container at a proper time. Further, the 
burden on the operator to handle the apparatus can be reduced since the 
notification is performed only when the operator is present near the 
apparatus.