JPH09185298A - Iamge forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of saving power with high reliability by preventing trouble such as the damage of a switch for turning on/off a power source and a serious accident such as contact welding. SOLUTION: A control part 210 turns off a resetting signal to a timer circuit 213, when there are no image forming operations and operation inputs from an operating part 211. The timer circuit 213 counts the duration of 'a standby state' without any image forming operations and operation inputs. When the counted time exceeds a predetermined time, a shutoff signal is outputted. An SSR 208 and a DC load 207 are stopped with AND gates 217 and 218, with the shutoff signal and a transistor 212 is turned on after a specified time, for instance, one second, with a delay circuit 209, to reset, that is, turn off a main switch 204.

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 such as a copying machine or a printer, and more particularly to power saving thereof.

[0002]

2. Description of the Related Art In recent years, a digital color copying apparatus has been developed in which a color image pickup apparatus using a CCD or the like and a digital color printer such as a laser beam printer or an inkjet printer have been developed. It has become possible to faithfully reproduce and record the data, and the demand for full-color copying machines is increasing year by year.

For example, in an electrophotographic full-color copying machine, an original is decomposed into R (red), G (green), and B (blue) for reading, and M (magenta), C (cyan), and Y (yellow) are read. , Bk (black) are converted into image signals of four colors to form an electrostatic latent image on the photosensitive drum. After that, the electrostatic latent image is developed for each color by a developing device to form a toner image, and the toner image is transferred to the recording paper. For all the colors, the toner image is transferred onto the recording paper and then fixed on the recording paper by the fixing device to obtain an image.

On the other hand, as a trend in the world in recent years, energy saving has been sought, and even if the copying machine as described above is not used for a certain period of time, the display of the operation unit is erased, the set temperature of the fixing device is lowered, and the like. However, it has been proposed to consume unnecessary energy as much as possible. Further, some devices have a function of shutting off power to the device itself, and have a function of turning off the power by itself after a predetermined time has elapsed.

[0005]

However, in the case of the above-mentioned conventional example, many energy-saving functions are merely auxiliary ones, and it is assumed that the operator often kills the function from the operation unit or the like. In reality, the frequency of use is not so high.

However, it is expected that demands for energy saving will increase in the future, such as legal regulations for energy saving represented by Energy Star are being considered. This is to limit the power consumption per unit time when the apparatus is in the standby state. In the color copying machine as in the conventional example, the heat energy required for the fixing device is high, so that the predetermined time is required. When the standby state continues, it is essential to cut off the power supply of the device. In this case, the operator manually turns on / off the power of the switch, and the device itself turns off the switch, so that the number of times of opening / closing of the switch is increased more than ever.

Therefore, by interrupting a high load at a high frequency, the contacts inside the switch are likely to be greatly damaged, and the probability of causing troubles such as switch damage and serious accidents such as contact welding increases. The problem is fully anticipated.

Further, in order to avoid the above-mentioned accident, the number of times of opening and closing of the switch is required to be several times higher than that in the conventional case, so that there is a problem that the cost of the switch itself is increased.

The present invention has been made under such circumstances, and reduces troubles such as damage to a switch that opens and closes a power source and reduces the possibility of occurrence of a serious accident such as contact welding. An object of the present invention is to provide an image forming apparatus that can realize reliability and power saving.

[0010]

In order to achieve the above object, according to the present invention, an image forming apparatus is configured as described in the following (1) to (4).

(1) A power-on means having a reset function, a load supplied with power by the power-on means, a standby detection means for detecting a standby state of the apparatus, and a standby detected by the standby detection means. Timer means for detecting that the state continues for a predetermined time or longer, and control means for stopping the load in response to detection of continuation of the standby state for a predetermined time or longer by the timer means, and subsequently resetting the power-on means. An image forming apparatus provided with.

(2) Power-on means having a reset mechanism, a load supplied with power by turning on the power-on means, standby detection means for detecting a standby state of the apparatus, and standby detected by the standby detection means. Timer means for detecting that the state continues for a predetermined time or longer, and control means for waiting for the load to stop and resetting the power-on means after the timer means detects that the standby state continues for a predetermined time or longer. Image forming apparatus equipped.

(3) The image forming apparatus according to (1) or (2), wherein the standby state is a state in which there is no image forming operation and no operation input.

(4) The image forming apparatus according to any one of (1), (2) and (3), wherein the load includes a fixing device.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to an embodiment of a full-color copying machine. The present invention is not limited to this full-color copying machine, and can be implemented in an appropriate image forming apparatus such as a black-and-white copying machine and a printer. Further, in each of the embodiments, the load has a fixing device, but the present invention is not limited to this, and the present invention can be implemented in a load having a high-output motor or the like. Further, in each of the embodiments, the main switch that is the power-on means is reset after a predetermined time from the stop of the load, but the present invention is not limited to this.
Detecting the stop of the load and resetting the power-on means, etc.
By appropriate means, the power-on means can be reset after the load is stopped.

[0016]

【Example】

(Embodiment 1) FIG. 1 is a sectional view showing the construction of a "full color copying machine" which is Embodiment 1. This copying machine is a full-color copying machine with an automatic double-sided function that employs an electrophotographic recording system in the image forming process.

In FIG. 1, reference numeral 101 denotes an image scanner unit which reads a power source up to A3 size and performs digital image signal processing. 102 is a printer unit,
This is a part for outputting an image corresponding to the original image read by the image scanner unit 101 on a sheet in full color.

The image scanner unit 101 includes a first scanning mirror 11, a second scanning mirror 12, a third scanning mirror 13,
CCD integrated with imaging lens 14, R, G, B filters
(Imaging element) 15 and original illumination lamp 18.

The original document placed on the original table glass 28 is illuminated by the original document illumination lamp 18, guided by the first to third scanning mirrors 11, 12 and 13, passes through the lens 14, and then the light receiving surface of the CCD 15. Projected on.

The original image projected on the light receiving surface of the CCD 15 is color-separated into full-color information red (R), green (G), and blue (B) components by an RGB three-color separation filter and converted into an electric signal for image processing. Sent to the section 103.

In the case of this embodiment, the CCD 15 has about 5000
In addition, the original illumination lamp 18 and the first scanning mirror 11 have pixels at a speed V, and the second and third scanning mirrors 12 and 13 are provided.
Scans the entire surface of the original by mechanically moving at a speed of 1/2 V in a direction perpendicular to the electrical scanning direction of the CCD 15.

The image processing unit 103 subjects the image signal to processing such as logarithmic conversion, UCR, masking, gradation correction, etc. for each of magenta (M), cyan (C), yellow (Y), and black (Bk). The components are decomposed and sent to the laser scanner unit 16 in the printer unit 102.

Further, one component of M, C, Y, and Bk is sent to the laser scanner unit 16 by one scan of the document in the image scanner unit 101, and a total of 4 components are sent.
One full-color recording is completed by scanning the document once.

The laser scanner unit 16 modulates and drives the semiconductor laser according to the image signal. The laser light emitted from the semiconductor laser is the laser scanner unit 1
Polygon mirror, lens, and fixed mirror 1 in 6
The photosensitive drum 1 is scanned via 7 to form an electrostatic latent image.

A primary charger 2 and a pre-exposure lamp 6 are arranged above the photosensitive drum 1, and a surface potential sensor 3 for measuring the surface potential of the photosensitive drum 1 is arranged on the upper right side. Before the electrostatic latent image is formed on the photosensitive drum 1, the pre-exposure lamp 6 exposes the photosensitive drum 1 to remove the electric charge remaining on the surface, and then the primary charger 2 uniformly disperses the charge. The charge is charged.

The surface of the photosensitive drum, which has been uniformly charged before image formation, is exposed by the laser scanner unit 16 with a predetermined amount of light, the surface potential at that time is measured by the surface potential sensor 3, and charging at the time of image formation is performed. Give feedback to control the quantity.

The latent image formed is formed into a toner image by the developing device 40 arranged below the photosensitive drum 1. The developing device 40 has a configuration in which four developing units 41, 42, 43 and 44 using a two-component developer in which toners of M, C, Y and Bk colors and carriers are mixed are stacked.
Each developing device is attached and detached so as to come close to the photosensitive drum 1 only when developing a corresponding color.

The toner image formed on the photosensitive drum 1 is transferred onto the recording paper P by the transfer device 5. After that, the toner remaining on the surface of the photosensitive drum 1 is removed by the cleaning device 7 to prepare for the next latent image formation.

The transfer device 5 includes an adsorption charger 51, a transfer sheet 52, a transfer charger 53, a separation charger 54, and a charge eliminator 55.
It consists of. The recording paper P fed from the paper cassettes 31 and 32 is electrostatically attracted to the transfer sheet 52 by the adsorption charger 51, and after the toner image is transferred by the transfer charger 53, the separation claw 8 and the separation charger 54. Is separated from the transfer sheet 52 by. Further, the charge remaining on the transfer sheet 52 is removed by the charge remover 55 to prepare for the next electrostatic attraction of the recording paper P.

In this way, the recording paper P to which the toner image is transferred by the transfer device 5 and separated is sent to the fixing device 20 by the transfer paper conveying system 25, and the toner image on the recording paper P is fixed.

The fixing device 20 includes an upper fixing roller 26, a lower fixing roller 27, a fixing cleaner 28, an upper fixing heater 29,
The lower fixing heater 30 is provided. The toner on the recording paper P is melted by the thermal energy of the upper fixing heater 29 and the lower fixing heater 30, and is entangled with the fibers of the recording paper P by the pressure applied between the upper fixing roller 26 and the lower fixing roller 30. Fix by. Fixing upper roller 2
An upper fixing heater 29 is arranged at the center of 6 and a lower fixing heater 30 is arranged at the center of the lower fixing roller 26. The surfaces of the upper fixing roller 26 and the lower fixing roller 27 are independently maintained so as to have a constant temperature. Temperature controlled. Further, a fixing cleaner 28 is disposed above the upper fixing roller 26, and dust attached to the surface of the upper fixing roller 26 is wiped off by a web impregnated with silicone oil.

The recording paper P fixed by the fixing device 20 is ejected by the ejection roller pair 24 by the ejection roller pair 24 at a preset mode, for example, at the end of copying in the single-sided mode or at the end of back-side copying in the double-sided mode. When the front side copy in the double sided mode is completed, the sheet is conveyed to the double sided unit 60 by the double sided flapper 61.

The duplex unit 60 includes a pair of reversing rollers 62,
It comprises a reversing tray 63, a duplex transport system 64, a reversing transport system 65, a reversing guide 66, and a duplex tray 67.

The recording paper P conveyed by the double-sided flapper 61 is guided by the double-sided conveying system 64 and sent to the reversing roller pair 62. The reversing roller pair 62 is used for the recording paper P.
When the recording paper P is sent to the reversing tray 63 in the direction of the arrow A in the figure by a predetermined length according to the size of the above, the recording paper P is then rotated in the opposite direction and sent in the direction of the arrow B, and is guided by the reversing conveyance system 65. And is conveyed to the double-sided tray 67. At this time, the recording paper P placed in the double-sided tray is prepared for the next back surface recording,
It is turned inside out with the trailing edge of the recorded surface as the beginning.
Further, a reversing guide 66 is provided at the joining point of the double-sided conveying system 64 and the reversing conveying system 65 so as not to enter the double-sided conveying system 64 when the recording paper P is fed in the direction of arrow B.

The recording paper P placed on the double-sided tray 67 is
Similar to the paper feeding from the paper cassettes 31 and 32, the paper is again sent to the transfer device 5, the image is transferred to the back surface, fixed by the fixing device 20, and discharged to the recording paper tray 23 by the paper discharge roller pair 24.

FIG. 2 shows a circuit diagram of a main part of this embodiment, which will be described below.

In FIG. 2, a plug 201 is an input plug for obtaining power supply from a commercial power source. Plug 2
The commercial power input from 01 is the circuit breaker 2
02, and is input to the main switch 204 via the noise filter 203.

Here, the circuit breaker 202 is a device for preventing an excessive current from flowing due to the insulation failure generated inside the machine. Further, the noise filter 203 is
The noise is removed so that various noises on the commercial power supply do not adversely affect the parts inside the device.

The main switch 204 is a seesaw switch with a reset function that has a relay inside. When the user manually operates the main switch 204, the contacts can be opened and closed to supply / shut off the electric power to the inside of the apparatus.
By energizing and exciting the internal relay, it is possible to release the contact and cut off the power supply.

Reference numeral 210 denotes a control unit for controlling the apparatus, which is composed of a CPU, ROM, RAM, I / O and the like (not shown). Further, reference numeral 211 denotes an operation unit, which is used by the operator to input a mode to be operated and instruct the control unit 210.

DC is provided downstream of the main switch 204.
A load such as a power supply 205 and a fixing device 206 is connected. The DC power source 205 is further connected to a DC load such as a motor, a clutch, a solenoid, sensors (not shown), an electric circuit for controlling the device, etc., but the description will be simplified in this embodiment. Therefore, the DC load 207 is simply used. The control unit 210 responds to the DC
The energization of the load 207 is controlled.

The fixing device 206 of the present embodiment is as described above.
A halogen heater of 600 W is used for each of the upper fixing heater 29 and the lower fixing heater 30. However, even if only the fixing upper heater 29 is described, it does not hinder the understanding, so the fixing device 206 will be described.

The fixing device 206 includes a thermostat 214, a fixing heater 215, and a thermistor 216 for preventing overheating.
It consists of. The control unit 210 detects the temperature of the fixing device 206 based on the signal from the thermistor 216, and the SSR 20
8, the fixing heater 215 is turned on / off to control the temperature to be constant. The SSR 208 is a zero-cross type AC switch using a triac, and can control energization to the fixing heater 215 by an ON / OFF signal of the fixing heater from the control unit 210.

Reference numeral 213 is a timer for counting the time for shutting off the power source, and is configured so that the count value can be cleared by a reset signal from the control unit 210. The control unit 210 is configured to output a reset signal and stop the operation of the timer circuit while the operator operates the keys of the operation unit 211 to set the mode and during the copy sequence.

FIG. 3 is an internal circuit diagram of the timer circuit 213. In FIG. 3, 301 is a 24-bit counter, and a 2 ms pulse is input to the clock. The reset signal from the control unit 210 is input to the clear terminal of the counter 301, and the operation of the counter 301 is stopped while the reset signal is L. A CPU (not shown) sets data to the data input of the counter 301. By changing the value of the set data, the time taken for shutoff can be changed. In this embodiment, 60 minutes is set as the default.

When the counter 301 counts up,
A pulse is output from the RC output and input to a flip-flop (hereinafter referred to as FF) 302. The FF 302 latches the output pulse from the counter 301. Also, FF
A reset signal 302 is cleared from the control unit 210.

The shutoff signal output from the timer circuit 213 is output to the delay circuit 209, the AND gate 217,
218 is input. AND gates 217 and 218 are
The SSR 20 is obtained by taking the logical product of the shut-off signal, the fixing heater-on signal, and the CD load signal-on signal that are inverted.
8. Input to the driver of DC load 207. When the shutoff signal becomes active, AND gates 217, 2
By 18, the fixing heater 215 and the DC load 207 are turned off.

The delay circuit 209 activates the relay-on signal for turning on the relay of the main switch 204 after the shut-off signal is activated.
It has a delay. The triac in the SSR 208 does not turn off immediately even if the control signal turns off, and does not cut off the power supply to the fixing heater 215 until the commercial power supply voltage passes through zero cross. Therefore, if the main switch 204 is shut off at the same time when the shutoff signal becomes active, the contact is opened while the supply current of the fixing heater 215 is flowing to the contact of the main switch 204, and the contact is damaged. Will be given. Therefore, the fixing heater 21
A delay circuit 209 is provided in order to turn off 5 and delay the power supply to be surely cut off.

FIG. 4 is an internal circuit diagram of the delay circuit 209. In FIG. 4, 401 is a low-pass filter including a resistor and a capacitor. When the input shutoff signal becomes active (H in this embodiment), the capacitor r is charged with the current limited by the resistor r. Therefore, according to the time constant determined by the resistor r and the capacitor C,
The voltage across the capacitor rises.

Reference numeral 403 is a circuit for determining the slice voltage. In this embodiment, a fixed resistor having the same resistance value R has a slice level of 1/2 of the power supply voltage.

Reference numeral 402 denotes a comparator, the filtering signal of the shutoff signal is input to the + terminal, and the slice level signal is input to the-terminal. Therefore, when the filtering signal of the shutoff signal exceeds 1/2 power supply voltage,
Since the relay-on signal becomes active (H), this time becomes the delay time. In this embodiment, the delay time is about 1 second.

The relay-on signal output from the delay circuit 209 drives the transistor 212 to excite the relay in the main switch 204, so that the main switch 2
The contact of No. 04 can be opened with a minimum load applied, and the device can be safely turned off.

FIG. 5 shows a timing chart showing the operation of this embodiment. When the device finishes the copy operation and enters the standby state, the control unit 210 releases the reset signal and starts the operation of the timer circuit 213 (state 50).
1). When the time T1 (60 minutes in this embodiment) has elapsed without any key operation by the operator, the control unit 210 activates the shutoff signal in order to turn off the power of the apparatus for energy saving (state 502).

At almost the same time that the shutoff signal becomes active, the fixing heater ON signal and the DC load ON signal are forcibly turned OFF. Time T2 (about 10 ms)
The fixing heater 215 is turned off (state 503) after (time is exaggerated in the figure), and the relay-on signal is activated by the delay circuit 209 after time T3 (about 1 second in this embodiment) has passed ( State 504). After that, the device in the main switch 204 is turned off by the relay (state 505).

With this configuration, when the power of the apparatus is automatically turned off at least to save energy,
Since the contact of the main switch 204 is opened after the state of the minimum load, the load applied to the contact is reduced, and the probability of causing an accident such as damage or welding of the contact can be reduced.

(Embodiment 2) FIG. 6 is a block diagram of essential parts of a "full color copying machine" which is Embodiment 2. In FIG. In the description, in FIG. 6, the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

In this embodiment, the control in the first embodiment is performed by software. This embodiment will be described with reference to FIGS.

In FIG. 6, reference numeral 601 denotes a CPU which performs a required control according to a control program stored in the ROM 602, and in this embodiment, a general-purpose microprocessor is used. A RAM 603 is a working memory of the CPU 601.

Reference numeral 604 is a timer, which counts an input clock having a predetermined frequency and outputs a pulse signal.
The output pulse output from the timer 604 is input to the interrupt input INTR of the CPU 601. In the case of this embodiment,
The timer 604 interrupts the CPU 601 once every 2 ms. Further, the CPU 601 can measure the time by incrementing the data of the area secured on the RAM 603 each time the interrupt is applied.

In 605, the CPU 601 controls the operation unit 211.
I / O for receiving a key input signal from the thermistor 216, temperature data from the thermistor 216, and operating the DC load 207, SSR 208, and shutoff transistor 212.
Port. In the case of the present embodiment, the CPU 601 and the timer 604 used are configured on one chip.

FIG. 7 shows the CPU 610 in the standby operation.
2 is a flowchart of control of.

After the power is turned on, the CPU 601 completes a predetermined power-on sequence, and the fixing device reaches a predetermined temperature to make a copy, or when the copy sequence ends and the next copy becomes possible. Start standby operation.

When the standby operation is started, step 7
At 01, it is checked whether there is a key operation from the operation unit 211. If there is no key operation, RA is performed in step 702.
The timer count area (hereinafter abbreviated as timer) secured on the M603 is incremented, and step 703 is performed.
Move on to In step 703, it is checked whether or not the timer has counted up (in this embodiment, 60 minutes are counted),
If it is not counted up, step 701 is performed again.
Return to

If there is a key operation in step 701, the timer is reset in step 704 and the process proceeds to step 703. Therefore, in this case, step 7 is inevitable.
It returns from 03 to step 701.

When the timer counts up in step 703, the operation of the CD load 207 is checked in step 705, and the process waits until the predetermined operation is completed. D
When the operation of the C load 207 ends, in step 706,
By turning off the SSR 208, the fixing heater 215 is turned off. After that, in step 707, the timer is set to measure 1 second, and the fixing heater 215 is waited until it is turned off. Then, in step 708, the transistor 212 is driven to excite the relay in the main switch 204. Shut down the device.

With such a configuration, when the load on the contacts is operating when the power of the device is automatically turned off at least for energy saving, the operation waits until the operation is finished, and the state of the minimum load is reached. From the
Since the contacts of the main switch 204 are opened, the load applied to the contacts is reduced, and the probability of causing accidents such as damage or welding of the contacts can be reduced.

[0067]

As described above, according to the present invention,
When the standby state continues for more than the scheduled time, the load on the switch contacts is minimized and the device power is shut down, so troubles such as switch damage and serious accidents such as contact welding can be prevented. It becomes possible to realize power saving with high reliability.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment.

FIG. 2 is a block diagram of a main part of the first embodiment.

[Fig. 3] Internal circuit diagram of timer

FIG. 4 is an internal circuit diagram of the delay circuit.

FIG. 5 is a timing chart of the first embodiment.

FIG. 6 is a block diagram of a main part of the second embodiment.

FIG. 7 is a flowchart showing the operation of the second embodiment.

[Explanation of symbols]

 204 main switch 209 delay circuit 210 control unit 211 operation unit 213 timer circuit 208 SSR

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuneo Motobo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Takashi Suzuki Takashi Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Akiko Kanno 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroyuki Tsuji 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuhito Ohashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tetsuya Nakamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. A power-on means having a reset function,
A load that receives power supply when the power-on means is turned on, a standby detection means for detecting a standby state of the device, and a timer means for detecting that the standby state detected by the standby detection means continues for a predetermined time or longer, An image forming apparatus comprising: a control unit that stops the load and then resets the power-on unit in response to detection of continuation of a standby state for a predetermined time or longer by the timer unit. 2. Power-on means having a reset mechanism,
A load that receives power supply when the power-on means is turned on, a standby detection means for detecting a standby state of the device, and a timer means for detecting that the standby state detected by the standby detection means continues for a predetermined time or longer, An image forming apparatus comprising: a control unit that waits for the load to stop and resets the power-on unit after the timer unit detects that the standby state continues for a predetermined time or longer. 3. The image forming apparatus according to claim 1, wherein the standby state is a state in which there is no image forming operation and no operation input. 4. The image forming apparatus according to claim 1, wherein the load includes a fixing device.