Electrophotography – Diagnostics – Unit or part identification
Reexamination Certificate
2002-05-01
2004-03-02
Ngo, Hoang (Department: 2852)
Electrophotography
Diagnostics
Unit or part identification
Reexamination Certificate
active
06701096
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image-forming device such as a printer, more specifically to the management of a consumable component in such a device.
2. Description of the Related Art
One example of an image-forming device in which the present invention can be practiced is the tandem color electrophotographic printer
1
shown in FIGS.
17
and
18
:
FIG. 17
is a side sectional view;
FIG. 18
is a schematic block diagram of the printing engine.
The printer in these drawings has a low-voltage power source
2
, a high-voltage power source
3
, and four printing mechanisms: a yellow (Y) printing mechanism
4
, a magenta (M) printing mechanism
5
, a cyan (C) printing mechanism
6
, and a black (K) printing mechanism
7
. The printing mechanisms include respective photosensitive drum units (ID units)
4
a
-
7
a
, light-emitting diode (LED) heads
4
b
-
7
b,
discharge lamps
4
c
-
7
c,
and transfer rollers
4
e
-
7
e,
and are driven by respective motors
4
d
-
7
d.
Printing media such as sheets of paper, not shown, are placed in a cassette tray
8
, and fed into the printer
1
by the rotation of a hopping roller
9
. An attraction roller
10
generates a static electric charge that holds the printing media to a transfer belt in a transfer belt unit
11
. Driven by the rotation of a transfer-belt driving roller
11
a,
the transfer belt carries the printing media past the printing mechanisms
4
-
7
, which perform printing processes that transfer yellow, magenta, cyan, and black toner images onto the printing media. The media next pass through a fuser
12
, which fuses the toner images onto them, and are finally delivered into a stacker
13
. The printing media may also be supplied manually, in which case they are fed into the printer
1
by a front roller
14
, but the subsequent printing operations are the same.
These printing operations are controlled by the engine controller
15
in FIG.
18
. The engine controller
15
controls the LED heads
4
b
-
7
b
through a relay board
16
, and directly controls the discharge lamps
4
c
-
7
c,
the above-mentioned motors (M)
4
d
-
7
d,
a hopping motor
9
d
that drives the hopping roller
9
, a belt motor
11
d
that drives the transfer-belt driving roller
11
a
, a heater motor
12
d
that drives a heating roller in the fuser
12
, a front motor
14
d
that drives the front roller
14
, and the power sources
2
,
3
. The low-voltage power source
2
supplies power to a heat source such as a halogen lamp (not shown) in the fuser
12
. The high-voltage power source
3
supplies power to the ID units
4
a
-
7
a
and the transfer belt unit
11
. The engine controller
15
is also connected to various sensors
17
, such as a sensor that senses the presence of printing media and a sensor that senses whether the printer's cover is open or closed.
In this printer
1
, the ID units
4
a
-
7
a,
the transfer belt
11
, and the fuser
12
are consumable components that must be replaced at the end of their service lives. To tell the user when to replace the consumable components, the printer has counters that count the cumulative number of rotations made by rotating parts such as the photosensitive drums. When a counter reaches a predetermined value, the printer displays a service-life alarm indicating that the corresponding consumable component needs replacement. Notified by this alarm, the user can replace the consumable component at the appropriate time.
When the consumable component is replaced, it is also necessary to reset the counter. It is known art to reset the counter automatically by means of the structure shown in FIG.
19
. The consumable component
20
, which may be any one of the ID units
4
a
-
7
a,
or the transfer belt
11
or fuser
12
, includes an internal fuse F
1
. The printer has a consumable-component sensing section
18
that senses whether the fuse F
1
is blown. If the fuse F
1
is not blown, the consumable-component sensing section
18
blows it and resets the counter.
The consumable-component sensing section
18
includes a transistor TR
1
, a resistor R
1
, and a central processing unit (CPU)
19
, the functions of which will be described below with reference to the flowchart in FIG.
20
.
When the printer's power is switched on or its cover is opened and then closed, to determine whether the consumable component
20
has been replaced, the CPU
19
reads (step S
201
) and tests (step S
202
) the input value at a one-bit digital input port IN, which is connected through fuse F
1
to ground and through resistor R
1
to a power supply (Vcc). If the input value is at the high logic level, indicating that fuse F
1
is already blown and the consumable component
20
is not new, the CPU
19
terminates the process in FIG.
20
. If the input value is at the low logic level, indicating that fuse F
1
is not blown and the consumable component
20
is new, the CPU
19
resets the counter that keeps track of the service life of the consumable component
20
(step S
203
), and outputs a ‘0’ pulse from an output port OUT (step S
204
), sending a current pulse through transistor TR
1
to blow fuse F
1
. To confirm that fuse F
1
has blown, the CPU
19
reads (step S
205
) and tests (step S
206
) the input value at the input port IN again. If the input value is at the high logic level, the process ends; if the input value is at the low logic level, steps S
204
, S
205
, and S
206
are repeated until the input value becomes high, or until a limit number of repetitions is reached.
Consumable components such as the ID units, transfer belt, and fuser have different specifications for different printers, and when they are replaced, the user may mistakenly install a consumable component of the wrong type. Since there are four ID units with different toner colors, the user may also install an ID unit of the wrong color.
When this happens, a conventional printer cannot recognize that the consumable component has been incorrectly replaced, and operates as if the replacement had been made correctly, creating various problems. One problem is that the user does not realize that the wrong consumable component has been installed until a defective printing result is obtained, at which point the user must replace the consumable component again, repeat the printing job, and either dispose of the consumable component that was mistakenly installed, or store it for later use. Another problem is that the mistakenly installed consumable component now has a blown fuse, so if it is later reinstalled and used, its counter will not be reset, and its service life will not be indicated correctly.
If consumable components with different specifications or colors have different external shapes, these problems can be avoided by a mechanical interlocking mechanism that prevents the installation of the wrong type of consumable component, but such mechanisms increase the manufacturing cost of the printer and the consumable component.
Instead of a fuse, the consumable component may have an internal memory circuit storing, for example, identification information and either a count value or a flag indicating whether the consumable component is new or not, but this memory circuit also increases the cost of the consumable component.
Another problem is that when a new consumable component is installed, its fuse may fail to blow. In this case, a conventional printer displays an alarm indicating that the consumable component is defective, and disables printing. The user must then replace the consumable component again, even though its functioning is not normally impaired by the fuse failure, and the failure may be due to a temporary condition that will disappear later.
A further problem is that the printer cannot distinguish between the state in which the consumable component is not installed, and the state in which the consumable component is installed but has a blown fuse. One conventional solution to this problem is shown in FIG.
21
. The consumable component
20
and sensing section
18
m
Arai Kazuaki
Negishi Koichi
Uchida Takao
Akin Gump Strauss Hauer & Feld & LLP
Ngo Hoang
Oki Data Corporation
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