JP2000131997A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming device for automatically, always and appropriately setting a standby time. SOLUTION: A time correspondence table as for the history of a power saving period just before an actual operation (power saving time Ts) and the corresponding standby period after the end of the actual operation (standby time Tr) is previously stored in a memory. In the case the power saving time Ts is <=20 minutes, the standby time is set to be 20 minutes, in the case the power saving time Ts is >20 minutes, the standby time Tr is sequentially set to that the standby time Tr may be shortened in reverse proportion to the length of the power saving time Ts until a lapse of 60 minutes. In the case the power saving time is >=60 minutes, the standby time is always set to be zero minute. Thus, the device is immediately made in a power saving state after the end of printing, in such a situation that the device is in use once in an hour or more hours, that is, in the case the device using frequency is low at night.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus which variably controls a standby state of a heat source of a fixing unit and a power consumption reducing state in accordance with the frequency of an image forming operation.

[0002]

2. Description of the Related Art Conventionally, electrophotographic image forming apparatuses such as plain paper facsimile apparatuses and page printers have been widely used. In these, a toner image formed on a sheet by an electrophotographic method is fixed on the sheet surface by a heat fixing device. In many cases, when the time during which no signal is received from the outside, that is, the time during which the printing operation of the received information is not performed, continues for a predetermined period or more, in order to save power consumption, the heater for the heat fixing device is used. As a power saving mode in which the duty ratio is reduced, the temperature of the thermal fixing device is controlled to be lower than the printable temperature.

FIG. 8 is a time chart showing the operation of an image forming apparatus having such a power saving mode. As shown in the figure, in the image forming apparatus provided with the power saving mode, the printing (printing) execution state, that is, the actual operation state of the apparatus main body,
The subsequent operation standby state and the power saving state after a predetermined time tr has elapsed are repeated.

In such a power saving mode, the apparatus enters an operation standby state after the actual operation of the main body, and an elapsed time (hereinafter simply referred to as a standby time) tr from the operation standby state to the power saving mode is set to an initial value at the time of factory shipment. For example, a setting (default) is set to 20 minutes, or a predetermined time is set in advance by setting by an input from an operation panel by a user or the like.

[0005]

However, the operating time of the image forming apparatus changes every moment, regardless of whether the standby time tr before entering the power saving mode is a default value or a user setting value. Therefore, in order to obtain a better power saving effect, there is an inconvenience that the user has to estimate the operation frequency and reset the preset standby time tr each time. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional circumstances,
It is an object of the present invention to provide an image forming apparatus that automatically determines a standby time until power saving is performed as an appropriate standby time according to a history of operation states.

[0007]

The structure of the image forming apparatus of the present invention will be described below. An image forming apparatus according to the present invention includes a fixing device having a heat source for fixing a toner image formed on a sheet on a sheet based on print data from a host device, and a fixing state in which the fixing unit can perform a fixing operation. When the fixing operation is not started within a predetermined time, the heat source is set to a lower power consumption state than the standby state, and the power consumption is reduced in response to a print signal from a host device. Fixing temperature control means for controlling the heat source to shift from the power reduction state to the standby state, wherein the fixing temperature control means variably sets the predetermined time. Means, storage means for storing the power consumption reduction time immediately before the transition from the power consumption reduction state to the standby state, and the longer the power consumption reduction time stored in the storage means, the longer the standby time Configured with a standby time change control means for controlling so as to shorten the setting of the predetermined time by the setting means.

The standby time change control means has data in which the power consumption reduction time and the standby time are set and stored in a predetermined relationship in advance, and based on the data, It is configured to control.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side sectional view illustrating a configuration of an image forming apparatus (page printer) according to an embodiment. As shown in FIG.
Is composed of a paper feeding unit 2, a printing unit 3, an image fixing unit 4, a control unit 5, and a paper transport mechanism distributed in each unit.

The paper feeding section 2 is an apparatus main body (image forming apparatus 1).
A paper cassette 7 detachably mounted from a front (right side in the figure) mounting opening 6, a large number of sheets 8 placed and stored in the paper cassette 7, and a paper feed end of the paper cassette 7 (see FIG. (The left end of the paper) and a paper feed roller 9 and a paper feed guide 11.

The paper feed roller 9 feeds one uppermost sheet of the paper 8 toward the rear of the apparatus (left side in the figure) for each rotation, and the paper guide 11 moves the paper 8 from above to the front of the apparatus. It is reversed and guided to the printing unit 3.

On the upstream side of the printing unit 3 in the paper transport direction, a transport roller pair 12 and a paper sensor 13 constituting a paper transport mechanism are provided.
An auxiliary roller 14 and a guide plate 15, which are other components of the paper transport mechanism, are disposed downstream of the printing unit 3 in the paper transport direction. A paper roller pair 16 is provided.

The printing unit 3 is a device that prints on the paper 8 based on print data output from the control unit 5 based on reception from the outside, and controls the photosensitive drum 17 and the vicinity of the photosensitive drum 17. It includes an initializing charging brush 18, an exposure head 19, a developing roller 22, a transfer charging roller 23, and a cleaner 24 disposed in a lower opening of the developing device 21, which are sequentially disposed in a surrounding manner.

The photosensitive drum 17 rotates in a counterclockwise direction in the figure by engaging with a drive system (not shown). The initialization charging brush 18 is connected to a high-voltage unit, which will be described later, and charges the peripheral surface of the photosensitive drum 17 to a uniform negative high potential. The exposure head 19 performs optical writing on the peripheral surface of the photosensitive drum 17 in accordance with the print data (dot-patterned data) output from the control unit 5, and the negative high potential and the optical writing by the above initialization are performed. As a result, an electrostatic latent image composed of a negative potential portion having a reduced potential is formed.

The developing roller 22 is rotatably supported by the developing device 21. The developing roller 22 also engages with a rotation drive system (not shown), rotates along the photosensitive drum 17, and is housed inside the developing device 21. The toner agitated and supplied by the agitator 25 is transferred (reversed development) to a negative low potential portion of the photosensitive drum 17 to convert the electrostatic latent image into a toner image. Transfer roller 23
Is connected to a high-voltage unit, which will also be described later, and applies a positive high voltage to the paper 8 fed to the printing unit 3 via the paper transport mechanism to transfer the toner image on the photosensitive drum 17 to the paper 8 I do. The cleaner 24 cleans toner remaining on the photosensitive drum 17.

The sheet 8 onto which the toner image has been transferred is carried into the image fixing section 4 via the auxiliary roller 14 and the guide plate 15. The image fixing section 4 includes a heat-insulating housing 25, a pair of fixing rollers 26 including a heating roller 26a and a pressing roller 26b surrounded by the housing 25, a fixing separation claw 27, and the like. The heat generating roller 26a has a fixing heater 30 built therein.
The sheet 8 carried into the image fixing section 4 is fixed to a pair of fixing rollers 26.
The toner image on the paper surface is fixed by heat and pressure, and the image is transferred onto the paper discharge tray 29 arranged in the opening 28 in front of the apparatus by the paper discharge roller pair 16. Is discharged upward.

A fan 31 is provided in the vicinity of the image fixing section 4 on the downstream side in the sheet conveying direction, and dissipates heat trapped inside the apparatus to the outside. An operation panel 32 is provided on the front upper surface of the apparatus main body, and includes a power button, various command input keys, a liquid crystal display device, an LED notification light, and the like.

The control unit 5 for controlling the operation of each unit is composed of an electrical unit 33 and an interface unit 34 for connecting the printer 1 to an external host device. A predetermined number of printed circuit boards on which a control device including a large number of electronic components is mounted is mounted on the electrical unit 33.

FIG. 2 is a block diagram showing a system configuration of the control unit 5. As shown in FIG.
It comprises an interface controller 35 and a printer engine controller 36. The interface controller 35 includes an MPU 37, a system ROM 38, a RAM 39, a font ROM 41, a non-volatile memory 42, a buzzer 43, an operation panel (operation panel) I / F (interface) 44 connected to the MPU 37 via a bus,
It comprises a video I / F 45, the above-mentioned interface unit 34 (extended I / F 34a, parallel I / F 34b) and a clock circuit 46.

The MPU 37 controls all the components. The system ROM 38 supplies a control program to the MPU 37. The RAM 39 has a work area for temporarily storing intermediate data generated during the control processing of the MPU 37 and a frame memory area for temporarily storing print data. The font ROM 41 stores a character font corresponding to the character code of the print data. The non-volatile memory 42 stores various default values.

The buzzer 43 emits a sound to notify a warning when the paper is out of paper, a paper jam occurs, or other maintenance is required. A key operation signal is input from the operation panel 32 to the operation panel I / F 44, and display data and lighting signals are output to the operation panel 32 from the MPU 37 via the operation panel I / F 44.

The video I / F 45 outputs a command signal and print data output from the MPU 37 to the printer engine controller 36. The extension I / F 34a is connected to a plurality of PCs (personal computers) 48 (48a, 48b, 48c,...) As host devices via a LAN board 47, and transmits dot pattern data (video data) as print data. Is entered. The parallel I / F 34b is an interface for connecting other devices. The clock circuit 46 oscillates a predetermined clock pulse signal used by the MPU 37 for processing.

On the other hand, the printer engine controller 36
Are a MPU 51, a video I / F 52, a control ROM 53, and a head I / F 5 connected to the MPU 51 via a bus.
4, fixing control unit 55, fan control unit 56, high-voltage control unit 5
7. The MPU 51 controls the control ROM 53 based on a command signal input from the interface controller 35 via the video I / F 52 and print data.
Each part of the printer engine controller 36 is controlled in accordance with the control program read from the printer.

The head I / F 54 outputs dot pattern data to the exposure head 19. The fixing control unit 55 controls the heat generation drive of the fixing heater 30 of the fixing unit 4. The fan control unit 56 controls driving of the fan 31. High pressure control unit 5
Reference numeral 7 controls the output of a high-voltage unit that supplies a high bias voltage to the initialization charging brush 18, the developing roller 22, and the transfer charging roller 23.

FIG. 3 is a flowchart of a processing operation by the interface controller 35 having the above-described configuration.
4 and 5 are flowcharts 1 and 2 of a processing operation by the printer engine controller 36 having the above configuration.

FIG. 6 (a) shows the power saving time Ts and the standby time T
FIG. 6B is a time characteristic table showing a relationship with the time r. FIG. 6B is a time correspondence table stored in a predetermined area of the RAM 39 in advance based on the time characteristic diagram.

FIGS. 7A and 7B are operation state diagrams showing an example of a standby time automatically set by the control unit 5 in the above processing operation. The processing operation of the control unit 5 will be described with reference to FIGS. In this process, it is assumed that the power saving mode has been designated by key input from the operation panel 32 before the start of printing. In the RAM 39, areas of a timer Tm, a standby time register Tr (using the same symbol as the standby time for convenience), and a power saving time register Ts (also using the same symbol as the power saving time) are set in advance.

First, as shown in FIG. 3, the extended I / F 34a of the interface controller 35 is set to "Redy".
In the state (step ST1), when the LAN board 47 receives the print data from the PC 48 (step ST1).
2) The print data is transmitted to the interface controller 35 (step ST3).

The MP of the interface controller 35
U37 analyzes the input print data via the extended I / F 34a, and converts the print data into bitmap data in the RAM 3.
9 in the frame memory area (step ST
4). When the development is completed, the bitmap data developed in the frame memory area is transferred to the video I / F.
45 to the printer engine controller 36 (step ST5), and again sets the extended I / F 34a to "R".
edy "state (step ST6).

The MPU 51 of the printer controller 36
Receives the bitmap data via the video I / F 52 (step ST7), releases the sleep mode (power saving mode) (step ST8), and starts warming up (step ST9). In this process, the fixing control unit 55, the fan control unit 56, and the high-voltage control unit 57 are each activated, whereby the fixing heater 30 is driven to generate heat, the fan 31 is driven to rotate, and the high-voltage unit 59 is driven to output.

When it is confirmed that the surface of the heat generating roller 26a has risen to a predetermined temperature by the warming-up process, each part of the transport mechanism is driven to feed the paper 8, and printing is started by the printing unit 3 (step ST10). , FIG.
(See time t1 in (a)). Then, at the timing when the printing surface of the paper 8 is fixed by the fixing unit 4 and the paper 8 is discharged onto the paper discharge tray 29, the printing process ends (step ST1).
1. See time t2 in FIG. 7 (a)).

Then, following the end of the printing process, since the power saving mode has just been designated before the start of printing and the history of the power saving time Ts has not been recorded yet,
The power saving time Ts = 20, which is the default value, is adopted. The power saving time data "20" is stored in the power saving time register Ts, and then the time saving table shown in FIG. Time data "2
The standby time Tr = 20 corresponding to “0” is read, the read standby time data “20” is set in the timer Tm, and the timer Tm is started (step ST1).
2) Enter a standby state where printing can be performed at any time (step S)
T13, see period t3 in FIG. 7 (a)).

Then, the interface controller 3
The standby state elapses without receiving the next print command from 5,
When the timer Tm counts up “20” (FIG. 7)
(See time t4 in (a)), power saving is set, and the timer Tm is started from "0" (step ST14). Each part of the printer engine is stopped by the setting of the power saving execution, that is, the heat generation of the fixing heater 30 is stopped,
1 stops, and the output of the high-pressure unit 59 stops (step ST15, see period t5 in FIG. 7A).

Next, when the LAN board 47 receives the print data from the PC 48 again, the interface controller 35 sends the print data to the printer engine controller 36.
Print data is output to

As a result, as shown in FIG. 5, when the printer engine controller 36 receives the print data (step ST16), the MPU 51 reads the time measurement data of the timer Tm and calculates the power saving time Ts (step ST17). The calculated power saving time data Ts (for example, "40" for the period t5 shown in FIG. 7A) is stored in the power saving time register Ts (step ST18). As a result, a history of the power saving time immediately before the start of the actual operation, for example, “40” is recorded.

Thereafter, the power saving mode is canceled (step ST).
19), start of warm-up (step ST2)
0), start of the printing process (step ST21), and
The printing process is sequentially terminated (step ST22) (see the period from time t6 to time t7 in FIG. 7A).
It should be noted that the processing in steps ST19 to ST22 is the same as that in FIG.
Are the same as the processes in steps ST8 to ST11 shown in FIG.

From here, processing of automatic correction (automatic setting) of the standby time, which is a feature of the present invention, is started. First, the power saving time data Ts (for example, the above-mentioned time data “40”) immediately before the actual operation stored in step ST18 is read from the power saving time register Ts, and the read power saving time data Ts ( The standby time data Tr (“10” in this case) corresponding to “40”) is read, and the read standby time data Tr (“1”) is read.
0 ") is set in the timer Tm, and after activating the timer Tm (step ST23), the apparatus is set in a standby state in which printing can be performed at any time (step ST24, refer to a period t8 in FIG. 7A)).

As described above, if the power saving time Ts immediately before the actual operation is long, for example, 40 minutes, a short standby time Tr (in this case, “10”) is set based on the history.

Thereafter, the interface controller 35
When the timer Tm counts up the newly set standby time Tr after the standby state has elapsed without receiving the next print command (see time t9 in FIG. 7A),
The execution of power saving is set, the timer Tm is started from "0" (step ST25), the heat generation of the fixing heater 30 stops, the rotation of the fan 31 stops, and the The output stops and the power saving state is set (step ST26, see period t10 in FIG. 7A).

Then, thereafter, as shown in FIG.
The same figure (a) again after only 10 minutes have passed after the power saving period t10.
When printing is started as shown in the printing period t11 of
It is recorded that the immediately preceding power saving period Ts was 10 minutes, and with the end of printing, the immediately preceding power saving period Ts = 10
Is read from the time correspondence table, and the standby time “20” is set as a new standby time Tr as shown in a period t12 in FIG.

If the printing is started as shown in the printing period t13 in FIG. 9A before the waiting time "20" is less than the predetermined time, the immediately preceding power saving time ts is less than 20 minutes. The waiting time of 20 minutes is read from the time correspondence table, and a new waiting time of 20 minutes is set after printing is completed. And if there is no next print command,
At time t15 when the set standby time 20 minutes has elapsed,
Power saving is started as shown in a period t16 in FIG.

In addition, the power saving state started from the time t9 is not 10 minutes as shown in the period t10.
When the time is 60 minutes as in the period t10 'shown in FIG. 7, this power saving time "60" is recorded, and the printing period t17 shown in FIG.
Ends, the power saving time T from the time correspondence table
The standby time Tr = 0 corresponding to s = 60 is read out, and the standby time data “0” is set in the timer Tm, so that the timer Tm is counted up as soon as the timer Tm is started. As shown in a period t18), immediately after the printing, the power saving state is entered.

As described above, the standby time is shortened in inverse proportion to the length of the power saving time, and when the power saving time immediately before the actual operation is particularly long, that is, it is a time zone in which the frequency of use is reduced. For example, if the length of the power saving time is 60 minutes or more, the standby time is set to always be "0" corresponding to this. As a result, the power saving state is set immediately after printing is completed, for example, when the printer is used less frequently, such as once during one hour or more, for example, at night.

[0044]

As described above in detail, according to the present invention, the standby time is determined based on the history of the operation status (power saving period) and the determined standby time is automatically set. Whenever the standby time needs to be changed due to the fluctuation of the above, the inconvenience and trouble of the user setting the standby time by estimation are eliminated, and therefore, it is possible to provide a user-friendly image forming apparatus.

Similarly, since the standby time is appropriately determined based on the history of the operation status, there is no waste in the time until the power saving state, and the power saving effect is improved.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view illustrating a configuration of an image forming apparatus (page printer) according to an embodiment.

FIG. 2 is a block diagram illustrating a system configuration of the image forming apparatus according to the embodiment;

FIG. 3 is a flowchart of a processing operation by an interface controller of the image forming apparatus according to the embodiment;

FIG. 4 is a flowchart (part 1) of a processing operation by a printer controller of the image forming apparatus according to the embodiment.

FIG. 5 is a flowchart (part 2) of a processing operation by the printer controller of the image forming apparatus according to the embodiment.

FIG. 6 (a) is a time characteristic diagram showing a relationship between a power saving time and a standby time as a calculation reference by a control unit, and FIG. It is a time correspondence table.

FIGS. 7A and 7B are operation state diagrams illustrating an example of a standby time automatically set by a control unit; FIGS.

FIG. 8 is a time chart illustrating an operation of an image forming apparatus having a conventional power saving mode.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 image forming apparatus 2 paper feed unit 3 printing unit 4 image fixing unit 5 control unit 6 mounting port 7 paper cassette 8 paper 9 paper feed roller 11 paper feed guide 12 transport roller pair 13 paper sensor 14 auxiliary roller 15 guide plate 16 paper discharge Roller pair 17 Photoreceptor drum 18 Initializing charging brush 19 Exposure head 21 Developing device 22 Developing roller 23 Transfer charging roller 24 Cleaner 25 Stirrer 25 Insulating housing 26 Fixing roller pair 26a Heating roller 26b Press roller 27 Fixing separation claw 28 Front Opening section 29 Paper discharge tray 30 Fixing heater 31 Fan 32 Operation panel 33 Electrical section 34 Interface section 34a Expansion I / F 34b Parallel I / F 35 Interface controller 36 Printer engine controller 37 MPU 38 System ROM 39 RAM 41 Phone ROM 42 Non-volatile memory 43 Buzzer 44 Operation panel (operation panel) I / F (interface) 45 Video I / F 46 Clock circuit 47 LAN board 48 (48a, 48b, 48c, ...) PC (personal computer) 51 MPU 52 Video I / F 53 Control ROM 54 Head I / F 55 Fixing control unit 56 Fan control unit 57 High voltage control unit 58 High voltage unit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takashi Inoue 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Co., Ltd. Tokyo Office F-term (reference) 2H027 DA12 DA38 DA40 EA12 ED25 EE08 EF15 FC08 2H033 AA32 BB00 CA04 CA05 CA07 CA30 CA32 CA44 9A001 BB06 HH23 LL09

Claims (2)

[Claims] A fixing device having a heat source for fixing a toner image formed on paper based on print data from a host device to the paper, and the fixing device is set to a standby state in which a fixing operation can be performed. The heat source is maintained at a predetermined temperature, and when the fixing operation is not started within a predetermined time, the power consumption is reduced to a lower power consumption state than the standby state, and the power consumption reduction state is responded to a print signal from a host device. A fixing temperature control unit that controls the heat source so as to shift from the standby state to the standby state. The fixing temperature control unit includes: a standby time setting unit that variably sets the predetermined time; A storage means for storing a power consumption reduction time immediately before the transition from the power reduction state to the standby state; and a standby time setting step as the power consumption reduction time stored in the storage means is longer. An image forming apparatus characterized in that a waiting time change control means for controlling so as to shorten the setting of the predetermined time by. 2. The apparatus according to claim 2, wherein the standby time change control unit has data in which the power consumption reduction time and the standby time are set and stored in a predetermined relationship in advance, and control is performed based on the data. The image forming apparatus according to claim 1.