Electrophotography – Control of electrophotography process – Control of fixing
Reexamination Certificate
2003-01-29
2004-09-14
Royer, William J. (Department: 2852)
Electrophotography
Control of electrophotography process
Control of fixing
C399S075000, C399S077000
Reexamination Certificate
active
06792223
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to image forming apparatus and, more particularly, to an image forming apparatus such as a digital copy machine or a digital printer that has a nonvolatile memory.
2. Description of the Related Art
In recent years, power-saving function is strongly required for image forming apparatuses from a viewpoint of environmental protection. In a conventional image forming apparatus using an electrophotographic process, the power consumption of a fixing part is dominant. A system, which realizes the power-saving function by maintaining a fixing part to a temperature lower than a temperature at the time of operation or interrupting power supply to the fixing part in a standby state, is widely used.
Recently, the power-saving technology has progressed further, and a system that interrupts power supply not only to the fixing part but the entire system or a large part of the system has been used. In this case, the power consumption at the time of standby becomes several watts or less, and an image forming apparatus having a very large power-saving effect can be achieved.
On the other hand, in consideration of convenience, a return time from a standby state is a very important element. That is, there are many cases where an image forming apparatus cannot be used immediately since the image forming apparatus is in the process of returning from a standby state, thereby deteriorating convenience very much.
In a case where the power-saving function in the standby state is achieved mainly by a temperature control of a fixing part, measures have been taken for an increase in efficiency of a heater, a formation of a thinner fixing roller and a reduction in the return time in association with other mechatronics parts. Consequently, the return time of a fixing part has been improved to the level of several minutes to the level of several seconds. On the other hand, generally in many cases, it takes several seconds to initialize a control part mainly containing a central processing unit (CPU).
In the case of the system which interrupts the power supply to the entire system or a large part of the system, if the return time is several minutes or several tens of seconds, the time of several seconds required for initialization is a negligibly short time with respect to the entire return time from a standby state. For this reason, there is no need to take the time required for initializing the control part into consideration.
However, in the recent image forming apparatus having the return time of a fixing part becoming the level of several seconds, several seconds required for initializing a control part influences greatly to the return time of the system.
It should be noted that, in the present specification, the term “fix” is used to represent an operation of fusing toner attached on a transfer sheet so as to securely bond the toner to the surface of the transfer sheet after cooling the fused toner. The fixing part may be referred to as a “fuser” in the field to which the present invention is related.
Hereafter, the initialization of the control part is explained.
FIG. 1
is a block diagram of a digital copy machine as a conventional image forming apparatus. Image data obtained by a read control part
1
is sent to a write control part
4
after image processing is applied by an image processing part (not shown in the figure) of a main control part
3
. The write control part
4
controls a laser diode (not shown in the figure) based on the image data sent from the image processing part, and forms an electrostatic latent image in an electrophotography process part
5
.
On the other hand, a toner image developed by the electrophotography process part
5
is transferred onto a transfer paper having been conveyed from a paper feed part (not shown in the figure). The toner image is fixed on the transfer paper by a fixing part (not shown in the figure) heated by a fixing heater
6
, and a copy
7
is formed. The fixing heater
6
is controlled by the main control part
3
, an IO control part
8
and a fixation control part
9
so that the fixing part is always maintained at a desired temperature during operation.
Additionally, in order to reduce the power consumption of the system at the time of standby, the fixing heater
6
is maintained at a temperature lower than that of operation, or the power supply to the fixing heater
6
is interrupted during the standby. Further, in the case of a system which interrupts the power supply to the entire system or a large part of the system, the power supply is interrupted not only to the fixing heater
6
but also to the main control part
3
, the IO control part
8
, and the fixation control part
9
.
It should be noted that the digital copy machine shown in
FIG. 1
is provided with, other than the above-mentioned parts, an operation part
10
, an auto-document feeder (ADF)
11
, a paper feed bank (BNK)
12
, sensors
13
, a clutch/solenoid (CL&SOL)
14
and a power source
15
.
FIG. 2
is a block diagram of the main control part
3
and the IO control part
8
of the digital copy machine shown in FIG.
1
. After a power is turned on, a central processing unit (CPU)
21
starts a series of operations upon cancellation of a reset signal generated by a reset integrated circuit (IC)
22
in accordance with a control program stored in a read only memory (ROM)
23
. A random access memory (RAM)
24
is used as a work area of the control program. Adjustment data of the image forming apparatus, history of use, and the like are stored in a nonvolatile memory
25
, and the stored data is used for maintenance. Since the CPU
21
has a general-purpose specification, the control program initializes the CPU
21
first after start of the operation. Additionally, since there are many cases where the contents of the RAM
24
are unfixed immediately after a power is turned on, the RAM
24
is initialized according to ALL“0” or ALL“1” write after the initialization of the CPU
21
. Further, since a CPU peripheral ASIC
26
and a peripheral control ASIC
31
also have a general-purpose specifications, the CPU peripheral ASIC
26
and the peripheral control ASIC
31
are initialized after the initialization of the RAM
24
.
Here, a description will be given of the peripheral control ASIC
31
in detail. The peripheral control ASIC
31
is mounted on a substrate different from a substrate on which the CPU
21
and the ROM
23
are mounted. For this reason, the peripheral control ASIC
31
is connected to an exclusive control bus separated from a CPU bus by the CPU peripheral ASIC
26
for the purpose of reduction in a load applied to buses.
The interfaces (I/F) of the I/O system, such as the ADF
11
, the bank
12
, the sensors
13
, the clutch/solenoid
14
, and the fixation control part
9
, are mainly connected to the peripheral control ASIC
31
. In order to make the general-purpose function of the peripheral control ASIC
31
correspond to the interfaces, it is necessary to perform an input setup, an output setup, and a serial communication setup.
FIG. 3
is a block diagram of the peripheral control ASIC
31
. The peripheral control ASIC
31
comprises a functional block
41
, a register block
423
and a CPU I/F
43
. The functional block
41
realizes each function such as a PIO, a UART, or a timer. The register block
42
performs various settings and operation control to the functional block
41
. The CPU I/F
43
is connected to control buses such as an address data bus or a data bus so as to perform an internal address decode and an access control to the register block
42
.
A description will be given below of the PIO as an example. Normally, all terminals of the PIO are set as input control ports by the register block
42
and I/O terminals are in a Hi-Z state so that a-control signal to a load is not turned active due to an unexpected output at a time of reset and after cancellation of the reset. The control signal to a load, which is desired to be inactive at the time of reset a
Ricoh & Company, Ltd.
Royer William J.
LandOfFree
Image forming apparatus for reducing a system return time 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 for reducing a system return time, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming apparatus for reducing a system return time will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3273562