Electrophotography – Diagnostics – Consumable
Reexamination Certificate
2001-07-12
2003-10-07
Ngo, Hoang (Department: 2852)
Electrophotography
Diagnostics
Consumable
C399S025000
Reexamination Certificate
active
06631248
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an image forming apparatus and to an apparatus unit, which has a non-volatile memory, removably attached to the main body of the image forming apparatus. More particularly, the invention relates to an image forming apparatus and to an apparatus unit thereof, wherein even if data in a non-volatile memory has been rewritten as a result of a malfunction in the image forming apparatus, the rewritten content can be restored, without internally providing the non-volatile memory with data back-up area, by controlling the method in which data is written from the main body of the image forming apparatus to the non-volatile memory.
BACKGROUND OF THE INVENTION
A laser printer
30
shown in
FIG. 14
is an example of an electrophotographic printer according to the prior art. The structure and functions thereof are as follows:
An optical unit
5
generates a laser beam
6
, and the laser beam
6
thus generated irradiates a photosensitive drum
1
. The latter is charged uniformly by a charging roller
2
. An electrostatic latent image is formed on the photosensitive drum
1
by the laser beam
6
that irradiates the drum.
The electrostatic latent image formed on the photosensitive drum
1
by the laser beam
6
is developed by toner in a developing unit
3
. A transfer charging roller
4
is for transferring the toner image, which has been formed on the photosensitive drum
1
, to a prescribed printing paper P. The toner image that has been transferred to the paper P is fused and fixed to the paper P by a fixing unit
7
.
Next, the paper P is ejected to the exterior of the machine by ejection rollers
12
. An ejection sensor
14
confirms whether or not the paper P has been ejected from the fixing unit
7
normally. The paper P is stacked in a standard cassette
8
. The paper P is transported from the standard cassette
8
by a paper feed roller
9
, and a registration sensor
13
is used to register the leading edge of the paper in order that the paper P may be printed on. Whether or not paper P is present in the standard cassette
8
is checked using a sensor
15
.
In a case where the printing paper P is supplied from a manual feed tray
10
, the paper is transported from the manual feed tray by a manual feed roller
11
. Whether or not paper P is present in the manual feed tray
10
is checked using a sensor
16
.
The above-described photosensitive drum
1
, charging roller
2
, developing unit
3
and toner are integrated within a toner cartridge
17
. The latter has a structure that allows it to be attached to and detached from the laser printer
30
. The toner cartridge
17
is fitted with a non-volatile memory
18
storing information relating to the toner cartridge
17
(e.g., status of use of the toner cartridge, whether or not it is necessary to replace the photosensitive drum, etc.).
In the prior art, signals are exchanged between a printer control unit
20
, which is provided in the main body of the laser printer
30
, and the non-volatile memory
18
mounted on the toner cartridge
17
, via a connector
19
. The printer control unit
20
writes data relating to, say, the status of use of the toner cartridge, to the non-volatile memory
18
and exercises control of the toner cartridge using this data, e.g., performs control such as management of whether or not the photosensitive drum requires replacement.
FIG. 15
is a block diagram illustrating the printer control unit
20
according to the prior art.
The functions of various blocks will be described first. A printer controller
101
communicates with a host computer (not shown), receives image data, expands the received image data into information capable of being printed by the printer, and exchanges signals with and communicates serially with a printer-engine controller
102
, described later.
The engine controller
102
exchanges signals with the printer controller
101
and controls the various blocks, described later, of the printer control unit
20
via serial communication. A paper transport controller
103
feeds and transports printing paper up to the point of paper ejection following printing in accordance with a command from the engine controller
102
, and an optics controller
104
drives a scanner motor (not shown) and controls the ON/OFF operation of the laser beam
6
in accordance with a command from the engine controller
102
.
A high-voltage controller
105
controls the output of high voltage, which is necessary for the charging, development and transfer steps of the electro-photographic process, in accordance with a command from the engine controller
102
, and a fixing-temperature controller
106
controls the temperature of the fixing unit
7
in accordance with a command from the engine controller
102
, and senses malfunction of the fixing unit
7
.
If information from a sensor indicating whether or not paper is present in the paper feeder and paper transport path, information indicative of a transport problem during paper transport or information indicative of a malfunction in any of the functional blocks of the printer is sensed by a paper-presence sensor input unit
107
, jam sensor
108
or malfunction sensor
109
, these sensors send the information to the engine controller
102
.
The toner cartridge
17
has a structure that allows it to be attached to and detached from the printer control unit
20
. The toner cartridge
17
is internally equipped with the non-volatile memory
18
capable of sending data to and receiving data from the engine controller
102
. Data can be read out of the engine controller
102
and data can be written to the engine controller
102
.
On the basis of data sensed by the printer controller
101
or printer control unit
20
, the engine controller
102
reads out the content of the non-volatile memory
18
or rewrites the content of the non-volatile memory
18
.
FIGS. 16 and 17
illustrate the exchange of signals between the printer control unit
20
and non-volatile memory
18
. The printer control unit
20
has an internal CPU
120
connected by a serial communication line to the non-volatile memory
18
inside the toner cartridge
17
via a drawer connector
121
.
The serial communication line comprises TDATA
124
, which is command data output from the printer control unit
20
to the non-volatile memory
18
, RDATA
125
, which is status sent back from the non-volatile memory
18
, SCLK
126
, which is a synchronizing clock, power supply VCC
122
and ground GND
123
.
TDATA
124
is a signal transmitted if the printer control unit
20
reads out the content of the non-volatile memory
18
and if the printer control unit
20
rewrites the content of the non-volatile memory
18
. Read-out/rewrite is specified using a command
127
(FIG.
17
).
Further, TDATA
124
transmits, in series following the command
127
, an address
128
to an address from which data is desired to be read, and data
129
if the data is desired to be rewritten.
If data is to be read out of the non-volatile memory
18
in response to the command
127
of TDATA
124
, an address
130
and the data
131
are sent back. If the non-volatile memory
18
is to be rewritten, the address
130
and write data
131
are sent back.
The conventional non-volatile memory
18
only has functions relating to the above-described read-out and write operations. For example, if the printer control unit
20
writes data that is important in terms of control, such as whether it is necessary to replace the toner cartridge
17
or not, to the non-volatile memory
18
, the memory
18
allows this important data to be recovered if it has been rewritten inadvertently due to effects of a malfunction or the like.
The method of recovering this important data is implemented by allocating, to a plurality of addresses, an area to which the important data is to be written. That is, even if a certain data area has been written due to effects of a malfunction or the like, the information at another address is read to perform control so as to recover the data or prevent the dat
Canon Kabushiki Kaisha
Ngo Hoang
LandOfFree
Image forming apparatus with restorable non-volatile memory does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image forming apparatus with restorable non-volatile memory, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming apparatus with restorable non-volatile memory will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3125956