U.S. patent application number 09/123367 was filed with the patent office on 2001-08-16 for recording apparatus.
Invention is credited to HASHIMOTO, HIROSHI, KIMIZUKA, JUNICHI.
Application Number | 20010013943 09/123367 |
Document ID | / |
Family ID | 26441725 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010013943 |
Kind Code |
A1 |
HASHIMOTO, HIROSHI ; et
al. |
August 16, 2001 |
RECORDING APPARATUS
Abstract
An image recording apparatus comprises an image information
generation unit for generating image information, a record control
unit for recording an image represented by the image information
generated by the image information generation unit and a
communication unit for transferring information between the image
information generation unit and the record control unit. The record
control unit has multi-level energy saving modes and the
communication unit includes a unit for designating at least one of
the multi-level energy saving modes from the image information
generation unit in response to command data outputted from the
image information generation unit.
Inventors: |
HASHIMOTO, HIROSHI; (TOKYO,
JP) ; KIMIZUKA, JUNICHI; (YOKOHAMA-SHI, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
26441725 |
Appl. No.: |
09/123367 |
Filed: |
July 28, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09123367 |
Jul 28, 1998 |
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08944417 |
Oct 6, 1997 |
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5828462 |
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Current U.S.
Class: |
358/1.13 |
Current CPC
Class: |
G03G 21/206 20130101;
G03G 15/2003 20130101 |
Class at
Publication: |
358/1.13 |
International
Class: |
B41B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 14, 1994 |
JP |
6-100766 |
Apr 10, 1995 |
JP |
7-109029 |
Claims
What is claimed is:
1. An image recording apparatus comprising: image information
generation means for generating image information; record control
means for recording an image represented by the image information
generated by said image information generation means; and
communication means for transferring information between said image
information generation means and said record control means, wherein
said record control means has multi-level energy saving modes, and
wherein said communication means includes means for designating at
least one of the multi-level energy saving modes from said image
information generation means in response to command data outputted
from said image information generation means.
2. An image recording apparatus according to claim 1, wherein said
communication means includes means for indicating transition from
one level energy saving mode to other level energy saving mode.
3. An image recording apparatus according to claim 1, further
comprising: means including a photo-sensor having a light emitting
element and a photo-sensing element for controlling deenergization
of said light emitting element in a predetermined level energy
saving mode.
4. An image recording apparatus according to claim 1, wherein said
communication means includes means for independently indicating the
energization of a predetermined load as the energy saving
control.
5. An image recording apparatus according to claim 1, further
comprising: detection means for detecting a user access to said
image recording apparatus; and means for stopping the energy saving
control when said detection means detects the user access.
6. An image recording apparatus according to claim 1, wherein said
communication means includes a signal for indicating that said
image information generation means is ready to communicate, and
when said record control means is not conducting the energy saving
control, said image information generation means renders said
record control means from an enable state to a disable state to
reset said record control means, and when said record control means
is conducting the energy saving control, said record control means
is not reset even if said communication ready signal is rendered
from the ready state to a not ready state to continue the energy
saving control.
7. An image recording apparatus according to claim 1, wherein said
communication means includes means for setting a time from the
designation of the energy saving control to the start of the energy
saving control by said record control means to said record control
means and means for setting a continuation time of the energy
saving control.
8. An image recording apparatus according to claim 1, wherein said
communication means includes means for simultaneously setting a
time before the start of the energy saving control by said record
control means and a time to continue the energy saving control.
9. An image recording apparatus according to claim 1, wherein said
image information generation means generates image information for
each pixel based on data of a predetermined command scheme
outputted from an external unit.
10. An image recording apparatus comprising: image information
generation means for generating image information; record control
means for recording an image represented by the image information
generated by said image information generation means; and
communication means for transferring information between said image
information generation means and said record control means; said
record control means including an MPU; said communication means
including means for stopping an operation clock of said MPU in
response to command data outputted from said image information
generation means.
11. An image recording apparatus according to claim 10, further
comprising start-up means for starting up the stopped operation
clock.
12. An image recording apparatus according to claim 11, wherein
said start-up means includes a start-up signal line in said
communication means between said image information generation means
and said record control means.
13. An image recording apparatus according to claim 11, wherein
said start-up means starts up said MPU in response to a reset
signal from said image information generation means.
14. An image recording apparatus according to claim 11, wherein
said start-up means starts up said MPU in response to a
non-maskable interrupt signal from said image information
generation means.
15. An image recording apparatus according to claim 10, further
comprising means for switching the energy saving mode between when
the energy saving mode is started up by a command code from said
image information generation means and when the energy saving mode
is started by the start-up signal line.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to energy saving control of an
image recording apparatus which has an interface with an external
unit such as a personal computer and records an image on a record
sheet based on image information inputted from an external unit
through the interface.
[0003] 2. Related Background Art
[0004] As an image recording apparatus of this type, a laser
printer which uses an electrographic process has been known. Many
laser printers have the following three types of operation
modes.
[0005] First, a print mode in which a record sheet is transported
and a print operation is carried out.
[0006] Secondly, a stand-by mode in which an immediate print
operation is ready. For example, in a laser printer having a
thermal fixing unit using a halogen heater, temperature control is
effected to maintain the thermal fixing unit at a slightly lower
temperature in the stand-by mode than a fixing temperature in the
print mode.
[0007] Thirdly, a sleep mode which is set by a social demand in
recent energy saving trend and in which a power consumption is
further reduced than that in the stand-by mode.
[0008] Many prior art laser printers comprise video control means
for generating bit map data for each pixel as a video signal from
data described by a command scheme such as PDL (page description
language) based on a record command from the external unit and
record control means for recording an image represented by the
video signal. The control of the operation modes is effected by the
record control means. A command to shift to the sleep mode and
return from the sleep mode is effected from the video control means
to the record control means based on information from the external
unit.
[0009] In the prior art sleep mode, however, since the energization
and deenergization of the thermal fixing unit used in the laser
printer are uniformly set, optimum energy saving control to fit a
variety of operation states of the printer is not attained.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide an image
recording apparatus which permits optimum energy saving control for
various operation states of the printer such as frequency of use
and reduction of financial burden to power consumption.
[0011] It is another object of the present invention to provide a
recording apparatus which can direct various types of sleep modes
from an external unit which supplies image information to the
recording apparatus.
[0012] Other objects, advantages and effects of the present
invention will be apparent from the accompanying drawings,
following description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a schematic sectional view of a laser printer
in a first embodiment of the present invention,
[0014] FIG. 2 shows a block diagram of a video interface of the
first embodiment,
[0015] FIG. 3 shows a timing chart for illustrating serial
communication in the video interface of the first embodiment,
[0016] FIG. 4 shows a timing chart of a print operation in the
first embodiment,
[0017] FIG. 5 shows a timing chart of the print operation in the
first embodiment,
[0018] FIG. 6 shows a state transition chart of sleep control in
the first embodiment,
[0019] FIG. 7 shows a list of command codes relating to the sleep
control in the first embodiment,
[0020] FIG. 8 shows a bit configuration of a sleep mode designation
command in the first embodiment,
[0021] FIG. 9 illustrates a relation between a sleep level code and
a process content in the first embodiment,
[0022] FIG. 10 shows a circuit diagram of a configuration relating
to fixing unit control and cooling fan control in the first
embodiment,
[0023] FIG. 11 shows a state transition chart of sleep control in a
second embodiment of the present invention,
[0024] FIG. 12 shows a circuit diagram of a configuration relating
to fixing unit control, cooling fan control and photo-sensor
control in a third embodiment of the present invention,
[0025] FIG. 13 illustrate a relation between a sleep level code and
a process content in the third embodiment,
[0026] FIG. 14 shows a timing chart of a detection timing of a
photo-sensor in the third embodiment,
[0027] FIG. 15 shows a bit configuration of a sleep mode
designation command in a fourth embodiment,
[0028] FIG. 16 shows a state transition chart relating to sleep
control in a fifth embodiment,
[0029] FIG. 17 shows a circuit diagram of a principal part of the
fifth embodiment,
[0030] FIG. 18 shows a timing chart illustrating a relation between
CPRDY and a printer state in a sixth embodiment of the present
invention,
[0031] FIG. 19 shows a state transition chart for sleep control in
a seventh embodiment,
[0032] FIG. 20 shows a list of command codes relating to the sleep
control in the seventh embodiment,
[0033] FIG. 21 shows a bit configuration of a sleep-in delay time
designation command in the seventh embodiment,
[0034] FIG. 22 illustrates a bit configuration of a sleep time
designation command in the seventh embodiment,
[0035] FIG. 23 illustrates a list of command codes relating to
sleep control in an eighth embodiment of the present invention,
[0036] FIG. 24 illustrates a bit configuration of a sleep-in delay
time designation/sleep time designation command in the eighth
embodiment,
[0037] FIG. 25 shows a block diagram of a video interface in a
ninth embodiment of the present invention,
[0038] FIG. 26 shows a state transition chart relating to the sleep
control in the ninth embodiment,
[0039] FIG. 27 illustrates a relation between a sleep level code
and a process content in the ninth embodiment,
[0040] FIG. 28 shows a circuit diagram of a configuration relating
to fixing unit control and cooling fan control in the ninth
embodiment,
[0041] FIG. 29 shows a block diagram of a configuration of a
control circuit of a clock oscillation circuit of an MPU of the
ninth embodiment,
[0042] FIG. 30 shows a block diagram of a configuration of a
control circuit of a clock oscillation circuit of an MPU of a tenth
embodiment of the present invention, and
[0043] FIG. 31 shows a state transition chart relating to sleep
control in an eleventh embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] Preferred embodiments of the present invention are now
described in conjunction with the accompanying drawings.
[0045] [First Embodiment]
[0046] FIG. 1 shows a schematic sectional view of a construction of
an image recording apparatus in an embodiment of the present
invention.
[0047] A laser printer main unit 1 (hereinafter referred to as a
main unit 1) has a cassette 2 for accommodating record sheets S, a
cassette sheet sensor 3 for sensing the presence or absence of the
record sheet S in the cassette 2, a cassette size sensor 4
(comprising a plurality of microswitches) for detecting a size of
the record sheet S of the cassette 2 and a sheet feed roller 5 for
feeding the record sheet S from the cassette 2.
[0048] A pair of registration rollers 6 for synchronously feeding
the record sheet S is arranged downstream the sheet feed roller 5.
An image forming unit 8 for forming a toner image on the record
sheet S based on a laser beam from a laser scanner unit 7 is
arranged downstream the pair of registration rollers 6.
[0049] A fixing unit 9 for thermally fixing the toner image formed
on the record sheet S is arranged downstream the image forming unit
8, and a sheet ejection sensor 10 for sensing the sheet transport
state of a sheet ejection unit, a sheet ejection roller 11 for
ejecting the record sheet S and a stack tray 12 for stacking
recorded sheet S are arranged downstream the fixing unit 9.
[0050] The laser scanner unit 7 comprises a laser unit 13 for
emitting a laser beam modulated with an image signal (VDO) sent
from an external unit 28 to be described later, a polygon motor 14
for scanning the laser beam from the laser unit 13 onto a
photoconductor drum 17 to be described later, a group of focusing
lenses 15 and a deflection mirror 16.
[0051] The image forming unit 8 comprises the photoconductor drum
17, a pre-exposure lamp 18, a primary charger 19, a developing unit
20, a transfer charger 21 and a cleaner 22 which are required in a
known electrographic process. The fixing unit 9 comprises a heat
roller 9a, a pressure roller 9b, a halogen heater 9c arranged in
the heat roller and a thermistor 9d for detecting a surface
temperature of the heat roller.
[0052] A main motor 23 is energized through a sheet feed roller
clutch 24 and the pair of registration rollers 6 are energized
through a registration roller 25, and units in the image forming
units 8, the fixing unit 9 and the sheet ejection roller 11 are
also energized.
[0053] An engine controller 26 controls the electrographic process
by the laser scanner unit 7, the image forming unit 8 and the
fixing unit 9 and controls the feed of the record sheet in the main
unit 1.
[0054] A video controller 27 is connected to the external unit 31
such as a personal computer through a general purpose interface
(Centronics, RS232C, etc.) 30 and develops image data sent from the
general purpose interface 30 into bit data which is converted to a
VDO signal and sent to the engine controller 26.
[0055] A video interface 28 is communication means between the
video controller 27 and the engine controller 26.
[0056] A cooling fan 29 is rotated and stopped by the engine
controller 26 to cool the interior of the printer, particularly the
video controller 27.
[0057] FIG. 2 shows a block diagram of a configuration of the video
interface 28 shown in FIG. 1.
[0058] In FIG. 2, CPRDY is a signal indicating that the external
unit 3 is ready to communicate, and it is sent from the video
controller 27 to the video controller 26.
[0059] PPRDY is a signal indicating that the engine controller 26
is ready to communicate and it is sent from the engine controller
26 to the video controller 27.
[0060] SBSY is a status valid signal which is sent from the engine
controller 26 to the video controller 27.
[0061] CBSY is a command valid signal which is sent from the video
controller 27 to the engine controller 26.
[0062] SC is a status/command signal. When the status valid signal
SBSY is true, it is sent from the engine controller 26 to the video
controller 27 as status data indicating the internal status of the
printer, and when the command valid signal CBSY is true, it is sent
from the video controller 27 to the engine controller 26 as command
data indicating a command from the video controller 27 to the
engine controller 26.
[0063] CLK is a synchronization clock of the status/command signal
SC and it is sent from the video controller 27 to the engine
controller 26. The engine controller 26 sends back a corresponding
status to each command from the video controller.
[0064] Namely, the signals SBSY, CBSY, SC and CLK conduct the hand
shaking serial communication.
[0065] RDY is a ready signal which is true when the engine
controller 26 is ready to print and it is sent from the engine
controller 26 to the video controller 27.
[0066] PRINT is a print signal which is true when the video
controller 27 indicates the start of print and it is sent from the
video controller 27 to the engine controller 26.
[0067] VSREQ is a vertical synchronization request signal by which
the engine controller 26 requests the output of a vertical
synchronization signal VSYNC to be described later to the video
controller 27.
[0068] VSYNC is the vertical synchronization signal for vertically
(sub-scan direction/sheet feed direction) synchronizing the image
output sent from the video controller 27 to the engine controller
26.
[0069] BD is a horizontal synchronization signal for horizontally
(main scan direction/laser scan direction) synchronizing the image
output sent from the engine controller 26 to the video controller
27.
[0070] VDO is an image signal by which the video controller 27
serially sends a dot image to the engine controller 26 in
synchronism with the vertical synchronization signal VSYNC and the
horizontal synchronization signal BD.
[0071] FIG. 3 shows a timing chart of a serial communication
operation.
[0072] When the main unit 1 is powered and the engine controller 26
is initialized and is ready for the serial communication, the
engine controller 26 renders the PPRDY true.
[0073] On the other hand, when the video controller 27 is powered,
initialized and is ready for the serial communication, the video
controller 27 renders CPRDY true. The video controller 27, after
confirming that the PPRDY is true for a predetermined time period,
determined that it is ready for the serial communication, and
renders CBSY true if necessary, and sends an 8-bit command through
the SC line in synchronism with CLK. Then, it renders CBSY false
and waits for the send-back of the status from the engine
controller 26.
[0074] When the engine controller 26 receives the command, it
renders SBSY true to send back the status in accordance with the
content of the command. When the video controller 27 detects the
true state of SBSY, it starts the transmission of CLK and the
engine controller 26 sends back the status through the SC line in
synchronism with CLK and renders SBSY false.
[0075] When the engine controller 26 confirms the true state of
CPRDY for a predetermined time period, it is determined that the
serial communication is ready and the command is valid.
[0076] FIGS. 4 and 5 show timing charts of a print operation of the
main unit 1. Referring to those figures, the print operation is
explained.
[0077] When the engine controller 26 is ready for the print
operation, it renders RDY true and informs the print ready state to
the video controller 27. In response thereto, the video controller
27 renders PRINT true if a print request is issued to indicate the
start of printing.
[0078] When the engine controller 26 detects the true state of
PRINT, it starts to drive the main motor 23 and the polygon motor
14. When the main motor is driven, the photoconductor drum 17, the
fixing roller (in the fixing unit 9) and the sheet ejection roller
11 are rotated. The engine controller 26 activates the high voltage
for the primary charger 19, the developing unit 20 and the transfer
charger 21, turns on the sheet feed clutch 24 to drive the sheet
feed roller 5 t1 second after the steady state of the rotation of
the polygon motor 14 (see FIG. 4), and feeds the record sheet S
toward the pair of registration rollers 6.
[0079] At the timing when the leading edge of the record sheet S
reaches the pair of registration rollers 6 (t2 second after the
drive of the sheet feed roller 5), the engine controller 26 sends
the vertical synchronization request signal VSREQ to the video
controller 27 and turns off the sheet feed clutch 24 to stop the
drive of the sheet feed roller 5.
[0080] When the video controller 27 completes the development of
the image information into the dot image and the image signal VDO
is ready to output, it confirms that the vertical synchronization
request signal VSREQ is true and renders the vertical
synchronization signal VSYNC true, and starts to output one page of
image signal VDO tV second later in synchronism thereto.
[0081] The engine controller 26 turns on the registration roller
clutch 25 t3 second after the rise of the vertical synchronization
signal VSYNC to drive the pair of registration rollers 6. The pair
of registration rollers 6 are driven for t4 second until the
trailing edge of the record sheet S is fed past the pair of
registration rollers 6.
[0082] During this period, the engine controller 26 sends the
horizontal synchronization signal BD to the video controller 27 at
a predetermined timing in synchronism with the laser scan and
modulates the laser beam emitted from the laser unit 13 based on
the image signal VDO.
[0083] As shown in FIG. 5, the video controller 27 outputs one scan
of image signal VDO in synchronism with the rise of the horizontal
synchronization signal BD.
[0084] When the next page is to be printed, the print signal PRINT
is rendered true t5 second later. Then, the same operation as that
for the first page is carried out.
[0085] Through the above operation, the record sheet S is
sequentially fed to the sheet feed roller 5, the pair of
registration rollers 6, the image forming unit 8, the fixing unit 9
and the sheet ejection roller 11 so that the image is recorded.
[0086] The energy saving, that is, the sleep control in the present
embodiment is now explained.
[0087] The printer 1 is either in the stand-by mode or in the sleep
mode except in the print mode and provided that no abnormal state
such as failure occurs.
[0088] In the stand-by mode, it may be immediately shifted to the
print mode upon the print request. Specifically, a temperature of
the fixing unit 9 is set to a lower temperature than a temperature
in the print mode (for example, the fixing unit temperature in the
stand-by mode is 150.degree. C. while the fixing unit temperature
in the print mode is 190.degree. C.) and the cooling fan 29 is
energized to cool the video controller.
[0089] On the other hand, in the sleep mode, the power consumption
is more reduced than that in the stand-by mode. The sleep mode has
a sleep level 0 and a sleep level 1. In the level 0, the
energization to the fixing unit 9 is stopped, and in the level 1,
the energization to the fixing unit 9 is stopped as well as the
energization of the cooling fan 29 is stopped. The shift from the
stand-by mode to the sleep mode is controlled by a command sent
from the video controller 27 to the engine controller 26 through
the video interface 28.
[0090] FIG. 6 shows a state transition chart illustrating the state
transition for the sleep control of the main unit 1.
[0091] As shown, the transition from the stand-by mode to the sleep
level 0 mode is effected by the sleep designation command and the
designation of the sleep level 0 by the sleep mode designation
command.
[0092] The transition from the stand-by mode to the sleep level 1
mode is effected by the sleep designation command and the
designation of the sleep level 1 mode by the sleep mode designation
command.
[0093] The mode is shifted to the stand-by mode from the level 0 or
level 1 sleep mode by a wake-up designation command.
[0094] FIG. 7 shows command codes relating to the sleep control.
45H in a hexadecimal code is allocated to the sleep designation,
and 46H is allocated to the wake-up designation.
[0095] The sleep mode designation is made by a 2-byte command. The
video controller 27 sends a command code 80H at the first byte, and
sends a predetermined command code at the second byte to designate
the sleep level.
[0096] FIG. 8 shows a bit configuration of the second byte of the
sleep mode designation command.
[0097] The command designates the sleep level by the three bits
(5th to 7th bits) of the eight bits.
[0098] FIG. 9 illustrates a relation between the sleep level code
and a process content. A code 000 designates the sleep level 0,
that is, the deenergization of the fixing unit. A code 001
designate the sleep level 1, that is, the deenergization of the
fixing unit and the deenergization of the cooling fan. Codes 010 to
111 are unused.
[0099] FIG. 10 shows a circuit diagram of a halogen heater drive
circuit for controlling the temperature of the fixing unit 9 shown
in FIG. 1 and a drive circuit for the cooling fan 29.
[0100] In FIG. 10, the halogen heater 9c in the fixing unit 9 is
connected to a commercial power source (AC power source) 32 through
a TRIAC 33a in a SSR 33 which is a solid state relay comprising the
TRIAC 33a, a LED 33b and a zero-crossing detection circuit (not
shown). When the LED 33b emits a light, the TRIAC 33a conducts and
the halogen heater is turned on. The LED 33b is connected to a +5 V
power supply (generated from the commercial power source by a low
voltage power circuit (not shown)) which powers the DC-powered
engine controller 26 and has a cathode thereof connected to a
collector of a grounded emitter NPN transistor 37. A base of the
transistor 37 is connected to an output port (OUT1) of the MPU 26a
through a grounded resistor 39 and a resistor 38.
[0101] The MPU 26a is a microcomputer which controls the engine
controller 26. When the MPU 26a renders the output port (OUT1) to L
(off), the LED 33b is not turned on and the halogen heater 9c is
not turned on. When it renders an output port (OUT2) to H (on), the
LED 33b is turned on and the halogen heater 9c is turned on.
[0102] The thermistor 9d in the fixing unit 9 has one end thereof
connected to the DC +5 V power supply and the other end thereof
connected to a resistor 35.
[0103] An analog voltage Vt determined by the thermistor 9d and the
resistor 35 is supplied to an A/D conversion input port of the MPU
26a and the MPU 26a detects the fixing unit temperature.
[0104] In the above arrangement, the MPU 26a monitors the fixing
unit temperature by the analog voltage Vt and changes an on/off
duty factor of the output port to control the temperature of the
fixing unit 9.
[0105] On the other hand, a transistor for driving the cooling fan
29 is connected to the output port (OUT2) of the MPU 26a through a
base resistor 41. A counter emf absorbing diode 43 for the cooling
fan 29 is connected to a DC +24 V power supply which powers to a
collector of the transistor 43 and the cooling fan. Accordingly,
when the MPU 26a renders the output port (OUT2) to H (on), the
cooling fan is energized, and when it renders the output port
(OUT2) to L (off), the cooling fan is deenergized.
[0106] In the above arrangement, the video controller 27 may
arbitrarily designates the sleep level 0 mode in which the cooling
fan is energized and the sleep level 1 mode in which the cooling
fan is deenergized.
[0107] [Second Embodiment]
[0108] A second embodiment of the present invention is now
explained. A difference between the second embodiment and the first
embodiment resides in that the sleep level may be changed only by
the sleep mode designation command.
[0109] FIG. 11 shows a state transition chart relating to the sleep
control in the second embodiment.
[0110] When the printer is in the sleep level 0 state and the video
controller 27 sends the sleep mode designation command to the
engine controller 26 while designating the sleep level 1, the
printer is shifted to the sleep level 1 mode. On the other hand,
when the printer is in the sleep level 1 mode and the sleep mode
designation command is sent while designating the sleep level 0,
the printer is shifted to the sleep level 0 mode.
[0111] In this manner, the video controller 27 may omit the wake-up
designation command and the sleep designation command when the
sleep level is to be changed so that a process load is reduced.
[0112] [Third Embodiment]
[0113] A third embodiment of the present invention is now
explained. A difference between the third embodiment and the first
embodiment resides in the addition of photo-sensor control to the
control in the sleep mode.
[0114] FIG. 12 shows a circuit diagram of the halogen heater drive
circuit, the cooling fan drive circuit and the photo-sensor control
circuit.
[0115] In FIG. 12, the halogen heater drive circuit and the cooling
fan drive circuit are identical to those of FIG. 10 shown for the
first embodiment and the explanation thereof is omitted.
[0116] The photo-sensor control circuit is now explained.
[0117] The laser printer of the present embodiment uses two
photo-sensors, one being a cassette sheet sensor 3 and the other
being a sheet ejection sensor 10. The cassette sheet sensor 3
comprises an LED 3a and a photo-transistor 3b and detects the
status by checking if a light from the LED 3a impinges to the
photo-transistor 3b or not.
[0118] An anode of the LED 3a is connected to the DC +24 V power
supply through a resistor 47 and a cathode thereof is connected to
a collector of a transistor 45. An emitter of the transistor 45 is
connected to GND and a base thereof is connected to an output port
(OUT3) of the MPU 26a through a base resistor 44.
[0119] Accordingly, when the MPU 26a renders the output port (OUT3)
to H, the LED 3a is turned on and the detection by the photo-sensor
is enabled, and when it renders the output port (OUT3) to L, the
LED 3a is turned off and the detection is disabled.
[0120] An emitter of the photo-transistor 3b is connected to GND
and a collector thereof is connected to an input port (IN1) of the
MPU 26a and a pull-up resistor 46. When the light from the LED 3a
is impinged to a base of the photo-transistor 3b, the input port
(IN1) is rendered to L, and if it is not impinged, the input port
(IN1) is rendered to H.
[0121] The same connection is made for the sheet ejection sensor
10, and the LED 3a in the above description corresponds to an LED
10a, the photo-transistor 3b corresponds to a photo-transistor 10b,
the resistor 47 corresponds to a resistor 49, the pull-up resistor
46 corresponds to a pull-up resistor 48, and the input port (IN1)
corresponds to an input port (IN2).
[0122] FIG. 13 illustrates a relation between the sleep level code
and a process content in the third embodiment.
[0123] In addition to the first embodiment, a photo-sensor
intermittent detection process for the sleep level 0 mode and a
photo-sensor detection stop process for the sleep level 1 mode are
added.
[0124] FIG. 14 shows a timing chart of the photo-sensor detection
process in the respective modes.
[0125] In the stand-by mode, the MPU 26a renders to output port
(OUT3) to H to turn on the LED 3a and the LED 10a so that the
detection by the photo-sensor is continuously effected. In the
sleep level 0 mode, the LED is turned on at an interval of a period
t10 (for example, 10 seconds) and the intermittent detection is
made only during that period. In the sleep level 1 mode, the LEDs
are turned off and the detection is stopped.
[0126] Through this control, the power consumption by the light
emission of the LED in the photo-sensor is reduced or eliminated
during the sleep mode so that further energy saving is
attained.
[0127] [Fourth Embodiment]
[0128] A fourth embodiment of the present invention is now
explained. A difference between the fourth embodiment and the third
embodiment resides in that the setting of the sleep level is
controlled by controlling the energization to the load in
accordance with the sleep mode designation command bit.
[0129] FIG. 15 shows a bit configuration of the second byte of the
sleep mode designation command in the fourth embodiment and a
process for the bit.
[0130] As shown, when the fifth bit is 1, the detection by the
photosensor is stopped, when the sixth bit is 1, the cooling fan is
deenergized, and when the seventh bit is 1, the fixing unit is
deenergized.
[0131] By this process, the video controller 27 may designate any
combination of sleep modes.
[0132] [Fifth Embodiment]
[0133] A fifth embodiment of the present invention is now
explained. A difference between the fifth embodiment and the first
embodiment resides in the addition of the detection of the direct
access to the printer by a user as a condition to transit from the
sleep mode to the stand-by mode.
[0134] FIG. 16 shows a state transition chart indicating the state
transition relating to the sleep control in the fifth
embodiment.
[0135] In the sleep level 0 mode and the sleep level 1 mode, the
mode is shifted to the stand-by mode when the wake-up designation
command is received as well as when the open state of a door (not
shown) of the printer which is opened when jam is to be processed
or when the user depresses a test print switch (not shown) to
print. In the test print, the mode is then shifted to the print
mode from the stand-by mode for effecting the test print.
[0136] FIG. 17 shows a circuit diagram of a principal portion of
the fifth embodiment.
[0137] A door switch 50 is opened when the door is opened and
closed when the door is closed. One terminal of the door switch 50
is connected to GND and the other terminal is connected to a
pull-up resistor 51 and the input port (IN3) of the MPU 26a.
Accordingly, the MPU 26a determines that the door is closed when
the input port (IN3) is L, and the door is open when the input port
(IN3) is H.
[0138] A test print switch 52 is normally open and closed when the
user depresses the test print switch 52. One terminal of the test
print switch 52 is connected to GND and the other terminal is
connected to a pull-up resistor 53 and an input port (IN4) of the
MPU 26a. Accordingly, the MPU 26a determines that the test print is
requested when the input port (IN4) is L, and the test print is not
requested when the input port (IN4) is H.
[0139] [Sixth Embodiment]
[0140] A sixth embodiment of the present invention is now
explained. A difference between the sixth embodiment and the first
embodiment resides in the control which does not accept soft reset
by the signal CPRDY in the sleep mode.
[0141] FIG. 18 illustrates a relation between the signal CPRDY and
the printer state in the sixth embodiment.
[0142] In the sleep level 0 mode and the sleep level 1 mode, the
sleep mode is maintained whether the state of CPRDY is true (H) or
false (L). The video controller 27 renders CPRDY true (H) and sends
the wake-up designation command, and after the printer state has
been shifted to the stand-by mode, it renders CPRDY false (L) so
that the engine controller 26 is reset and the printer is
initialized.
[0143] Accordingly, even if CPRDY is rendered false by the energy
saving control (partial deenergization in the video controller) of
the video controller 27 when the printer is in the sleep mode, the
engine controller 26 is not reset and the sleep mode is
maintained.
[0144] [Seventh Embodiment]
[0145] A seventh embodiment of the present invention is now
explained. A difference between the seventh embodiment and the
first embodiment resides in that a time from the transmission of
the sleep designation command to the transition to the sleep mode
and a time from the transition to the sleep mode to the automatic
wake-up are settable.
[0146] FIG. 19 shows a state transition chart indicating the state
transition relating to the sleep control in the seventh
embodiment.
[0147] As shown, when the sleep designation command is received in
the stand-by mode, the mode is shifted to the sleep mode designated
by a sleep mode designation command after a delay time designated
by a sleep-in delay time command to be described later.
[0148] On the other hand, the mode is shifted from the sleep mode
to the stand-by mode after the elapse of the sleep time (the time
elapsed after the transition to the sleep mode) designated by a
wake-up designation command of a sleep time designation command to
be described later.
[0149] The sleep-in delay time designation and the sleep time
designation are now described.
[0150] FIG. 20 illustrates the commands relating to the sleep
control in the seventh embodiment.
[0151] The sleep-in delay time designation is effected by the
sleep-in delay time designation command which is the second byte
command as is the sleep mode designation command. The first byte of
the sleep-in delay designation command is 83H and the second byte
is configured as shown in FIG. 21. The binary value of the six
bits, second to seventh bits of the second byte indicates a time
with one bit corresponding to ten minutes.
[0152] Namely, if it is 000111 (B), it represents 6.times.10
minutes so that the delay time of 60 minutes is designated.
[0153] On the other hand, the sleep-in time is designated by the
sleep time designation command which is the second byte command.
The first byte of the sleep time designation command is 85H and the
second byte is configured as shown in FIG. 22. The binary value of
six bits, the second to seventh bits of the second byte indicates a
time with one bit corresponding to ten minutes.
[0154] For example, if it is 001000 (B), it indicates 8.times.10
minutes so that the sleep time of 80 minutes is designated.
[0155] By this arrangement, the video controller 27 may reduce the
time management process for the sleep control.
[0156] [Eighth Embodiment]
[0157] An eighth embodiment of the present invention is now
explained. A difference between the eighth embodiment and the
seventh embodiment resides in the consolidation of the sleep-in
delay time designation command and the sleep time designation
command.
[0158] FIG. 23 illustrates commands relating to the sleep control
in the eighth embodiment.
[0159] The sleep-in delay time designation and the sleep time
designation are effected by a sleep-in delay time designation/sleep
time designation command which is a 2-byte command. The first byte
of the command is 83H and the second byte is configured as shown in
FIG. 24. The binary value of three bits, second to fourth bits of
the second byte indicates the sleep-in delay time and the binary
value of three bits, fifth to seventh bits indicates the sleep
time, with one bit corresponding to 30 minutes.
[0160] For example, if it is 010100 (B), it indicates 4.times.30
minutes so that the delay time of 2 hours is designated, and
8.times.30 minutes so that the sleep time of 4 hours is
designated.
[0161] Thus, both the sleep-in delay time and the sleep time can be
designated by the single command so that the command configuration
and the exchange thereof are simplified.
[0162] [Ninth Embodiment]
[0163] A ninth embodiment of the present invention is now
explained. In the present embodiment, the construction of the laser
beam printer is common to that shown in FIG. 1 and the explanation
thereof is omitted. A basic operation is also common to that
described in connection with FIGS. 3 to 5 and the explanation
thereof is omitted.
[0164] FIG. 25 shows a block diagram of a configuration of the
video interface 28 shown in FIG. 1.
[0165] In FIG. 25, RESET is a reset signal by which the video
controller 27 hard-resets the engine controller 26. Others are
common to those shown in FIG. 2 and the explanation thereof is
omitted.
[0166] The energy saving or the sleep control in the present
embodiment is now explained.
[0167] The printer 1 is either in the stand-by mode or in the sleep
mode except in the print mode provide that no abnormal state such
as failure occurs.
[0168] In the stand-by mode, the mode may be immediately shifted to
the print mode upon print request. Specifically, the temperature of
the fixing unit 9 is set to a lower temperature than that in the
print mode (for example, the fixing unit temperature in the standby
mode is 150.degree. C. while the fixing unit temperature in the
print mode is 190.degree. C. and the cooling fan 29 is energized to
cool the video controller.
[0169] On the other hand, in the sleep mode, the power consumption
is further reduced than that in the standby mode. The sleep mode
includes three levels, sleep level 0, sleep level 1 and sleep level
2. In the level 0, the fixing unit is deenergized, in the level 1,
the fixing unit 9 is deenergized as well as the cooling fan 29 is
deenergized, and in the level 2, in addition to the level 1, the
clock of the MPU 26a in the engine controller is stopped. The
transition from the standby mode to the sleep mode is effected in
accordance with a command sent from the video controller 27 to the
engine controller 26 through the video interface 28.
[0170] FIG. 26 shows a state transition chart illustrating the
state transition relating to the sleep control of the main unit
1.
[0171] As shown, the mode is shifted from the stand-by mode to the
sleep level 0 mode by the sleep designation command and the
designation of the sleep level 0 by the sleep mode designation
command.
[0172] The mode is shifted from the stand-by mode to the sleep
level 1 mode by the sleep designation command and the designation
of the sleep level 1 by the sleep mode designation command.
[0173] Further, the mode is shifted from the stand-by mode to the
sleep level 2 mode by the sleep designation mode and the
designation of the sleep level 2 by the sleep mode designation
command.
[0174] The mode is shifted from the level 0 or level 1 sleep mode
to the stand-by mode by the wake-up designation command.
[0175] When hard-reset is applied in the level 2 sleep mode, the
mode is shifted to the stand-by mode through the initial reset.
[0176] In the commands relating to the sleep control, 45H of the
hexadecimal code is allocated to the sleep designation and 46H is
allocated to the wake-up designation, as shown in FIG. 7.
[0177] The sleep mode designation is of 2-byte command
configuration. The video controller 27 sends the command code 80H
at the first byte and sends a predetermined command at the second
byte to designate the sleep level.
[0178] The second byte of the sleep mode designation command is
configured as shown in FIG. 8.
[0179] The command designates the sleep level by the 3-bit (fifth
to seventh bits) of the 8 bits.
[0180] FIG. 27 illustrates a relation between the sleep level code
and a process content in the present embodiment. The code 000
designates the sleep level 0, that is, the deenergization of the
fixing unit. The code 001 designates the sleep level 1, that is,
the deenergization of the fixing unit and the deenergization of the
cooling fan. The code 010 designates the sleep level 2, that is,
the stop of the clock of the MPU 26a. The codes 011-111 are
unused.
[0181] FIG. 28 shows a circuit diagram of the halogen heater drive
circuit for controlling the temperature of the fixing unit 9 shown
in FIG. 1 and the drive circuit for the cooling fan 29.
[0182] Basically, it is identical to that shown in FIG. 1 for the
first embodiment but in the present embodiment, the MPU 26a uses
the NEC .mu.PD78214 and has a crystal oscillator 68 shown and RESET
* terminal (where * indicates a negative logic).
[0183] The sleep mode 2 is now explained in detail.
[0184] The sleep modes 0 and 1 are designated by the MPU 26a and
the MPU 26a continues its operation even during the sleep mode
while the MPU 26a per se does not operate in the sleep mode 2. In
the sleep mode 2, the MPU 26a stops the oscillation and stops the
overall operation.
[0185] The MPU 26a may be operated with a very small power
consumption with a leakage current only. This is referred to as a
stop mode of the MPU.
[0186] FIG. 29 shows a block diagram of a configuration of a
control circuit of a clock oscillation circuit of the MPU 26a.
Referring to FIG. 29, an internal operation of the MPU 26a is
explained.
[0187] When the MPU 26a receives the sleep mode 2 request, it
carries out the sleep mode process, that is, deenergizes the fixing
unit 9 and deenergizes the fan 29 and renders PPRDY of the
interface signal 28 false and then sets the bit 1 of a stand-by
control register STBC 61 through an internal bus. Thus, a stop
flip-flop 62 is set and stops the operation of a system clock
oscillator 64 which generates a clock by using the crystal
oscillator 63.
[0188] When the oscillator 64 is stopped, a frequency divider 65
which divides the output of the oscillator 64 is also stopped and
the clock supplied to the MPU 26a is stopped so that the entire MPU
26a is stopped. Thus, the stop mode is entered.
[0189] In order to wake up from the stop mode, the system should be
hard-started up. The start-up may be effected by a non-maskable
interrupt terminal NMI or a reset signal. In the ninth embodiment,
a method by the reset signal is explained.
[0190] When a signal RESET of the interface signal 28 of FIG. 25 is
applied to the terminal RESET * of the MPU 26a, the stop flip-flop
62 is reset through an inverter 66 and an OR circuit 67 of FIG. 29
and the system clock oscillator 64 is started and the MPU 26a is
started.
[0191] The MPU 26a is reset simultaneously with the start so that
it is initialized such as memory clear and port initialization. To
start up from the sleep mode, whether a command 46H, the wake-up
designation is to be used or the reset signal is to be used is
stored by the video controller 27.
[0192] If PPRDY signal is false, the reset signal from the video
controller 27 may be outputted.
[0193] [Tenth Embodiment]
[0194] A tenth embodiment of the present invention is now
explained.
[0195] In the tenth embodiment, another start-up method from that
of the ninth embodiment is explained. In the ninth embodiment, the
signal RESET is applied to the terminal RESET * of the MPU 26a.
Thus, the initialization operation is started simultaneously with
the start-up from the sleep mode and the memory is cleared.
[0196] Thus, when the signal PPRDY of the interface signal 28 is
rendered true after the start-up, it is necessary for the video
controller 27 to conduct the entire communication protocol from the
beginning.
[0197] In the tenth embodiment, as shown in FIG. 30, the signal
RESET for the start-up is applied to the non-maskable interrupt
terminal NMI of the MPU 26a.
[0198] In this case, the MPU 26a is started up without being reset.
After the start-up, the engine controller 26 is immediately set to
the stand-by mode and the signal PPRDY of the interface signal 28
is rendered true. Thus, the video controller 27 need not conduct
the initial protocol to start the communication with the printer
and the data in the memory of the MPU 26a is maintained.
Accordingly, the retransmission of the data prior to the sleep is
not necessary.
[0199] The signal RESET is not the reset function and it may be
correctly referred to as a signal WAKE-UP.
[0200] [Eleventh Embodiment]
[0201] An eleventh embodiment of the present invention is now
explained.
[0202] FIG. 31 illustrates a state transition relating to the sleep
control capable of changing the level during the sleep.
[0203] When the printer is in the sleep level 0 or 1 and the video
controller 27 sends the sleep mode designation command to the
engine controller 26, and if the sleep level 2 is designated, the
printer is shifted to the sleep level 2 mode.
[0204] When a printer is in the sleep level 0 and the sleep level 1
is designated, the printer is shifted to the sleep level 1, and
when the printer is in the sleep level 1 and the sleep level 0 is
designated, the printer is shifted to the sleep level 0.
[0205] However, when the printer is in the sleep level 2, it is not
possible to change the sleep level by the command because the MPU
26a is not operating and the signal RESET is applied to the
terminal RESET * or the terminal NMI to reset it to the stand-by
mode.
[0206] Since the wake-up designation command and the sleep
designation command may be omitted in changing the sleep level, the
process load is reduced.
[0207] In accordance with the present invention, the function to
designate the mode from the video control means for a plurality of
sleep modes in the recording means is provided in the communication
means so that optimum energy saving control to various operation
conditions of the printer such as the frequency of use and the
reduction of the financial burden of the power consumption is
attained.
[0208] The present invention should not be limited to the above
illustrated embodiments but many modifications thereof may be made.
The above embodiments may be combined in any manner and they are
within the scope of the present invention.
* * * * *