JP4801980B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a copying machine, a facsimile machine, and a printer.

Conventionally, a photosensitive drum, a semiconductor laser for forming a latent image on the photosensitive drum, and a large number of transport rollers for transporting recording paper from the paper feed cassette to the photosensitive drum, transfer paper discharge section, etc. A transfer paper transport system mainly configured, a drive source for rotating the photosensitive drum and the transport roller, and in a normal state, the respective units are not closed so as not to contact the user of the apparatus. In an image forming apparatus equipped with an openable / closable door, the output of the DC power supply is turned off when it is detected that the door has been opened so as to prevent various problems including accidental power down due to the opening / closing of the door. When the closed state is detected, the output of the DC power supply is turned on after waiting for a certain time, or the voltage of the DC power supply is increased stepwise after detecting the closed state (for example, Patent Document 1) there is.
JP 2001-272885 A

However, in the conventional image forming apparatus described above, since it detects that the door is closed and waits for a certain period of time or increases the output of the DC power supply step by step, it takes time until the output of the power supply rises. There was a problem. In addition, a door opening / closing detection sensor is required separately from the control unit, which increases the cost of parts.
The present invention has been made in view of the above points, and prevents problems caused by accidental power down associated with the opening and closing of the door of the main body of the apparatus, and the power supply can be turned on in a shorter time after detecting that the door is closed. The purpose is to enable the use of the device by raising the output.

To achieve the above object, the present invention opens and closes an output path of a power source having a low output voltage among the plurality of power sources by opening and closing a door including a power source device including a plurality of power sources having different output voltages and a cover or a door. A first switch; a second switch that opens and closes an output path of a power supply having a high output voltage among the plurality of power supplies by opening and closing the first switch; and a control unit that is connected to an output path subsequent to the first switch. When the control means detects that the output from the output path downstream of the first switch is an output indicating the open state of the first switch when the door is opened, the control means outputs the power to the power source having the high output voltage. When the door is closed and it is detected at least twice in succession that the output from the output path downstream of the first switch is an output indicating the closed state of the first switch. To provide an image forming apparatus having a means for starting the output to a high output voltage power supply.

In the image forming apparatus as described above, when the control unit detects the output indicating the closed state of the first switch twice in succession, the detection time interval is the opening / closing of the first switch. And a first total time obtained by totaling the bounce time until the first switch is fully opened or closed during the opening / closing operation of the first switch, the opening / closing operation time of the second switch, It is preferable that the time interval is equal to or greater than the larger total time of the second total time, which is the sum of the bounce time until the switch fully opens or closes when the two switches are opened and closed.
Further, in the image forming apparatus as described above, the detection time interval when the control unit detects an output indicating the open state of the first switch is the operation time of opening and closing the first switch. , A first total time obtained by adding up the bounce time until the first switch is fully opened or closed during the opening / closing operation of the first switch, the opening / closing operation time of the second switch, and the opening / closing of the second switch It is preferable that the time interval be equal to or greater than the larger total time of the second total time, which is the sum of the bounce time until the fully opened state or closed state during the operation.
Furthermore, in the image forming apparatus as described above, the detection time interval when the control means detects the output indicating the closed state of the first switch is the operation time of opening and closing the first switch. And a first total time obtained by summing up the bounce time until the first switch is fully opened or closed during the opening / closing operation of the first switch, the opening / closing operation time of the second switch, It is preferable that the time interval be equal to or larger than the larger total time of the second total time, which is the sum of the bounce time until the fully opened state or closed state during the opening / closing operation.

  The image forming apparatus according to the present invention prevents inadvertent power-down caused by the opening / closing of the door of the apparatus main body, and raises the output of the power supply in a shorter time after detecting that the door is closed. Can be used.

Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.
〔Example〕
FIG. 2 is a diagram showing an example of the appearance of the image forming apparatus according to the embodiment of the present invention.
The image forming apparatus is, for example, a digital color copying machine, and includes a main body unit 10 that performs a copying operation including a large-capacity sheet feeding unit that accommodates and supplies a large amount of sheets, and sorts and punches the copied sheets. And a finisher (abbreviated as “FIN”) 9 for performing each process including binding.
The main body 10 has an automatic document feeder (abbreviated as “ADF”) 2 provided at the top thereof so as to be freely opened and closed. The document set on the ADF 2 passes through the scanning position by the scanner unit by the ADF 2. Thus, the contact glass 1 is conveyed. Further, the original can be read by placing the original on the contact glass 1 provided on the upper portion of the main body 10.

On the upper part of the main body 10 is provided an operation unit 3 on which a display panel for displaying various information to the user and an interface including buttons for the user to input various instructions are arranged. The user can use the operation unit 3 to specify switching of copy modes including, for example, monochrome, single color, two colors, and full color (four colors).
A main power switch 7 for turning on / off the main power of the image forming apparatus is provided on the upper portion of the main body 10. The user activates the image forming apparatus by turning on the main power switch 7. In addition, by turning off the main power switch 7, the power supply from the commercial power source to the image forming apparatus can be turned off and the operation can be stopped.
Further, a power sub key 4 is provided on the upper portion of the main body 10, and the image forming apparatus can be shifted to the energy saving mode by operating the power sub key 4, and the power sub key 4 is operated in the energy saving mode. By doing so, it is possible to return to the normal mode.

A door including a front door (front cover) 5 and a toner cover 8 is provided on the front side of the main body 10 so as to be openable and closable, and the front door 5 and the toner cover 8 are opened when maintenance or parts replacement is performed. It can be in a state.
The front door 5 is composed of two covers, a left door (left door) and a right door (right door), and a switch that is turned on / off in conjunction with the opening and closing of the left door and the right door is shown in the figure. Although one is provided inside each of the left door and the right door.
The main body 10 is provided with a paper feed tray 6, and the image forming apparatus forms an image on a recording medium including paper and an OHP sheet stored in the paper feed tray 6.

FIG. 1 is a block diagram showing a configuration of a main part according to the present invention including a control unit of the image forming apparatus shown in FIG.
The power supply device 20 includes a 5VDC power supply circuit 21 that supplies a current of 5V voltage to the control unit 51 and the relay unit 40 of the control device 50, and a 24VDC power supply that supplies a current of 24V voltage to the load unit 52 via the relay unit 40. The circuit 22 comprises a plurality of direct current (DC) power supplies.
As described above, power supply to the control unit 51 and the relay unit 40 and power supply to the load unit 52 are performed by different DC power supply circuits.

On the voltage supply line from the 5VDC power supply circuit 21 to the control unit 51 and the relay unit 40, the left door switch 30 and the right door switch 31 are provided in series. The left door switch 30 and the right door switch 31 are switches that are turned on / off in conjunction with the opening and closing of the left door and the right door of the front door 5. That is, it corresponds to a first switch that switches to an on or off state in conjunction with opening or closing of the door including the cover or door.
The relay unit 40 is an interlock relay and includes a first coil 42 and a second coil 43 that open and close the first relay contact unit 44 and the second relay contact unit 45 depending on whether or not the 5VDC power supply circuit 21 is energized. 41 is a relay switch. That is, it corresponds to a second switch that switches start and stop of power supply from the power source to the load unit in conjunction with the switching of the first switch.

In this embodiment, since the power supply to the load part 52 of the interlock system has a large capacity, a case where two relays with one contact are provided as an interlock application is shown.
The control device 50 includes a control unit 51 and a load unit 52 that are realized by a microcomputer (which may be an MPU) including a CPU, a ROM, and a RAM.
In the control unit 51, a voltage supply line from the 5VDC power supply circuit 21 is connected to an input terminal (also referred to as a “switch opening / closing detection terminal”) 53 for detecting 5V voltage. That is, it corresponds to detection means for detecting the open state and the closed state of the door based on the state of the first switch.
The control unit 51 has an interrupt timer function, and performs a timer interrupt process and outputs a 24V voltage generation command signal to the 24VDC power supply circuit 22 of the power supply device 20.

That is, the control unit 51 determines that the door is in an open state when the open state is detected by the detection means, and the door is in a closed state when the closed state is detected continuously twice or more. Based on the determination result, the function of the control means for controlling the start and stop of the power supply to the power source is achieved, and the switching of the first switch is performed as a time interval for continuously detecting the closed state twice or more. The first total time that is the sum of the operation time and the bounce time when the switch is not completely turned on or off, and the switching operation time of the second switch and the feeding start or stop completely during the switching operation. The time interval is set to be equal to or greater than the larger total time of the second total time obtained by adding the bounce time when the state is not in the state.
The above bounce time is an unstable state in which the contacts are intermittently opened and closed due to the collision of the contacts when the switch (including the relay switch) is operated and restored, and the contacts are not completely closed (or not fully opened). It's time.

Further, when it is determined that the door is in an open state, power supply to the load unit is stopped for the power source, and when it is determined that the door is in a closed state, the power source is supplied to the load unit. The control for starting the power supply is also performed.
Further, when the door is in the open state, the detection results of the open state and the closed state by the detection means are monitored at a time interval equal to or greater than the greater of the first total time and the second total time. Control is also performed.
When the door is in the closed state, the detection results of the open state and the closed state by the detecting means are monitored at a time interval equal to or shorter than the smaller of the first total time and the second total time. Control is also performed.

  The load unit 52 is driven by the power supply from the 24 VDC power supply circuit 22 and conveys the recording paper from the paper feed cassette to a photosensitive drum, a transfer paper discharge unit, and the like on which a latent image is formed by laser light irradiation by a semiconductor laser. A transfer paper conveyance system mainly composed of a large number of conveyance rollers, and a motor as a drive source for rotating the photosensitive drum and the conveyance rollers.

First, the basic operation of an interlock system using this interlock relay will be described.
In a state where both the left door and the right door of the front door 5 are closed, both the left door switch 30 and the right door switch 31 are closed, and 5V voltage is supplied from the 5VDC power supply circuit 21 to the control unit 51 and the relay unit 40. When the left door or the right door of the front door 5 is open, at least one of the left door switch 30 and the right door switch 31 is opened to cut off the supply of 5V voltage from the 5VDC power circuit 21 to the control unit 51 and the relay unit 40. To do.
When 5V voltage is supplied from the 5VDC power supply circuit 21 to the first coil 42 and the second coil 43 of the relay unit 40, the first coil 42 and the second coil 43 are respectively connected to the first relay contact unit 44 and the second relay. The contact portion 45 is turned on and closed, and a 24 V voltage is supplied from the 24 VDC power supply circuit 22 to each load of the load portion 52.

When the 5V voltage from the 5VDC power supply circuit 21 is not energized to the coil part 41, the first coil 42 and the second coil 43 are opened with the first relay contact part 44 and the second relay contact part 45 turned off, respectively. The supply of 24V voltage from the 24VDC power supply circuit 22 to each load of the load unit 52 is cut off.
Thus, when the left door and the right door of the front door 5 are both closed, power is supplied to the load section 52, and when the left door or the right door is opened, power supply to the load section 52 is interrupted. Therefore, the driving power is not applied to the load section 52 including the motor and the high temperature / high pressure section, and the safety of the user in a state in which the user can directly contact the load section 52 can be ensured.

Next, the operation time of the left door switch 30, the right door switch 31, and the relay unit 40 and the bounce time of the relay unit 40 will be described.
The operation time of the left door switch 30 and the right door switch 31 is generally 0 ms, the bounce time is generally several ms, and the longest time is, for example, 10 ms. Therefore, the total time of the operation time and the bounce time of the left door switch 30 and the right door switch 31 (corresponding to “first total time”) is 10 ms.

Further, the maximum operating time from when the coil portion 41 of the relay unit 40 is energized until the first relay contact portion 44 and the second relay contact portion 45 are actually closed is, for example, 20 ms. After the relay contact portion 44 and the second relay contact portion 45 are closed, the first relay contact portion 44 or the second relay contact portion 45 bounces, and the first relay contact portion 44 and the second relay contact portion 45 are stabilized. The maximum bounce time until closing is, for example, 10 ms.
Therefore, the total time of the operation time and the bounce time of the relay unit 40 (corresponding to the “second total time”) is 30 ms.
Since the above-described operation time and bounce time vary depending on the characteristics of switches and relays actually used in the image forming apparatus, it is preferable to use values measured each time.

Next, when the front door 5 is in the closed state, the control unit 51 monitors the left door switch 30 and the right door switch 31 as the time interval for monitoring the on-state and off-state detection results. Total time of operation time and bounce time of door switch 31 (corresponding to “first total time”) 10 ms, and total time of operation time and bounce time of relay unit 40 (corresponding to “second total time”) 30 ms The smaller one of them is set to a time interval of 10 ms or less, for example, 10 ms.
Further, when the front door 5 is in the open state, the operation time of the left door switch 30 and the right door switch 31 is set as a time interval for monitoring the detection results of the on state and the off state of the left door switch 30 and the right door switch 31. And the total time of the bounce time (corresponding to “first total time”) 10 ms, and the total of the operation time of the relay unit 40 and the bounce time (corresponding to “second total time”) 30 ms, whichever is larger The total time is 30 ms or more, for example, 50 ms.

Next, power supply control processing of the power supply device 20 shown in FIG. 1 will be described.
FIG. 3 is a waveform diagram for explaining power supply control processing of the power supply device 20 shown in FIG.
After the image forming apparatus is turned on, as shown in FIG. 5C, the control unit 51 sets the time interval of the interrupt timer to 10 ms and starts counting, and energizes the input terminal 53 for 5V voltage detection. Monitor for the presence or absence of

  First, when both the left door and the right door of the front door 5 are closed, the left door switch and the right door switch are closed and on (ON) as shown in FIG. As shown in FIG. 5B, the control unit 51 detects that the 5V voltage is supplied to the input terminal 53 for 5V voltage detection because the 5V voltage is high. Then, as shown in (d) of the figure, it is determined that the opening / closing judgment result of the left and right doors is in the closed state, and as shown in (e) of the figure, a 24V voltage generation command signal is sent to the 24VDC power supply circuit 22. As a result, the 24VDC power supply circuit 22 outputs a 24V voltage to the load section 52, as shown in FIG.

  Next, when the left door or the right door of the front door 5 is opened, the left door switch and the right door switch are opened and turned off (OFF) as shown in FIG. Therefore, as shown in (b) of the figure, the 5V voltage to the input terminal 53 for 5V voltage detection becomes low, and as shown in (c) of the figure, the control unit 51 When it is detected that the 5V voltage to the input terminal 53 for detecting the 5V voltage is in the low state by counting the interrupt timer, the time interval of the interrupt timer is changed to 50 ms. As shown in (d) of the figure, it is determined that the open / closed determination result of the left and right doors is in the open state, and as shown in (e) of the figure, output is turned off as a 24 V voltage generation command signal to the 24 VDC power supply circuit 22 ( OFF) command is sent, and as a result, (f) in the figure As shown, 24VDC power supply circuit 22 stops the output of the 24V voltage to the load 52.

Next, during transmission of the output off command to the 24VDC power supply circuit 22, the control unit 51 executes timer interrupt processing every 50 ms by counting the interrupt timer, and sets the input terminal 53 for 5V voltage detection to high. Monitor row status.
As shown in (a) of the figure, the left door switch and the right door switch are closed again and turned off, and as shown in (b) of the figure, the input terminal 53 for 5V voltage detection is again turned on. As shown in FIG. 5C, the control unit 51 detects the 5V voltage in both the first and second timer interrupt processes every 50 ms after the output stop instruction to the 24VDC power supply circuit 22. When it is detected that the input terminal 53 is in the high state, the time interval of the interrupt timer is changed to 10 ms again, and the open / close determination result of the left and right doors is closed as shown in FIG. As shown in (e) of the figure, an output on (ON) command is sent to the 24VDC power supply circuit 22 as a 24V voltage generation command signal, and as a result, as shown in (f) of the figure, The 24VDC power supply circuit 22 returns to the load unit 52 again. To start the output of 24V voltage.

FIG. 4 is a flowchart showing processing when the main power switch (main power SW) of the image forming apparatus is turned on.
When the main power switch of the image forming apparatus is turned on, the 5VDC power circuit and the 24VDC power circuit of the power supply apparatus are activated, the control unit of the control apparatus is activated, the interrupt timer is activated, and the process proceeds to timer interrupt processing. To do.

FIG. 5 is a flowchart showing timer interrupt processing of the control unit shown in FIG.
In this process, the control unit 51 determines whether or not the signal at the input terminal for 5V voltage detection is in a high state in step (indicated by “S” in FIG. 1). Flag is “1” (a flag set in the register of the control unit when it is detected that the input terminal for 5V voltage detection is in a high state and the left door switch or the right door switch is closed) When the 5V voltage detection flag is “1”, the front door state information is “closed” in step 3 (stored in the memory of the control unit when it is determined that the front door is closed). Output ON command is output as a 24V voltage generation command signal, the output of the 24VDC power circuit is turned on, and the timer interrupt time (interrupt timer time interval) of the interrupt timer is set to 10 ms. And return to the first process .

If it is determined in step 1 that the signal at the input terminal for detecting the 5V voltage is not in the high state but in the low state, the front door state information is “open” in step 4 (the front door is determined to be in the open state). Information stored in the memory of the control unit at times), an output off command is output as a 24V voltage generation command signal to turn off (stop) the output of the 24VDC power circuit, and the timer interrupt time of the interrupt timer Set (interrupt timer time interval) to 50 ms, set the 5V voltage detection flag to “0”, and return to the first process.
If it is determined in step 2 that the 5V voltage detection flag is not “1”, the 5V voltage detection flag is set to “1” in step 5 and the process returns to the first process.

Further, the above process will be described.
As soon as either the left door or the right door of the front door 5 is opened, the 5V voltage is not supplied to the 5V voltage detection input terminal 53 of the control unit 51, which is detected by a 10 ms timer interrupt. When the energization is no longer detected, exactly when the high signal is no longer detected, the control unit 51 determines that the front door 5 is in the “open” state.
In response, the control unit 51 sets the “24V voltage generation command signal” as an output off command, and the 24VDC power supply circuit 22 stops generating and outputting the 24V voltage based on the output off command from the control unit 51. Supply of 24V voltage to the load unit 52 is cut off.

Further, after the front door 5 is in the “open” state, the time interval of the interrupt timer for detecting the 5V voltage is changed from 10 ms to 50 ms. Therefore, the control unit 51 monitors the state of the input terminal 53 for 5V detection every 50 ms.
As a result, since the load of the software process is detected at a shorter time interval, the load of the software process is reduced since the load is detected at a longer time interval.

Next, when the opened front door 5 is closed (closed), the coil portion 41 of the relay portion 40 is energized again. Thereby, the first relay contact part 44 and the second relay contact part 45 of the relay part 40 are closed.
At the same time, since the 5V voltage is supplied to the 5V voltage detection input terminal 53, the control unit 51 confirms that the state of the 5V voltage detection input terminal 53 is high in the first 50 ms timer interrupt process. If it is detected and it is detected that the state of the input terminal 53 for 5V voltage detection is high even in the second 50 ms timer interruption process, it is determined that the front door is “closed”.

Here, the reason why the front door 5 is determined to be “closed” after detecting the high state twice in succession is that the input terminal 53 for 5V voltage detection is in a high state rarely due to noise or the like. When the input terminal 53 for detecting 5V voltage goes to the high state twice in order to prevent erroneous detection of noise or the like because the high state may be erroneously detected by the detection process every 50 ms. This is because the output of the 24 VDC power supply circuit 22 is restarted.
When the control unit 51 determines that the front door 5 is “closed”, the control unit 51 outputs the 24V voltage generation command signal to the 24VDC power supply circuit 22 as an output on command, whereby the output of the 24V voltage from the 24VDC power supply circuit 22 rises again.
For the sake of safety and reliability, the output of the 24VDC power supply circuit 22 may be resumed when the high state of the input terminal 53 for 5V voltage detection is detected three or more times continuously.

  In the above-described processing, the determination time for closing the front door 5 (the time until it is detected that the input terminal 53 for 5V voltage detection is continuously in the high state) is bounced with the operation time of the interlock relay. When the front door 5 is determined to be closed by setting it to be longer than the time, the first relay contact portion 44 and the second relay contact portion 45 of the relay portion 40 are securely closed, and thereafter When the 24V voltage generation command signal is set to the output on command and the generation of the 24V voltage from the 24VDC power supply circuit 22 is resumed, when viewed from the first relay contact portion 44 and the second relay contact portion 45, FIG. As shown, the 24V voltage rises slowly from 0V to 24V. This is because the 24V voltage is not generated at the moment when the first relay contact portion 44 and the second relay contact portion 45 are closed, so that a large rush does not flow from the 24VDC power supply circuit 22 side to the load portion 52 side. .

Accordingly, since the electric charge is gradually supplied from 0 V to the capacitor on the load portion 52 side, a large inrush current does not flow. In this way, since inrush current does not flow to the relay unit 40 and the load unit 52, various problems caused by inrush current including wear of relay contacts, malfunction of the overcurrent detection circuit of the DC power supply circuit, malfunction of the CPU, and the like. It can be prevented in advance.
Unlike the control in which the output of the 24V power supply circuit is turned on after waiting for a certain time after the front door 5 is closed or the output voltage is increased stepwise, there is no time loss.

Further, since the output on command is output to the 24VDC power supply circuit 24 immediately after the front door 5 is closed, the 24V voltage can be quickly raised to a predetermined potential, and the user of the image forming apparatus is made to wait. It has the effect of reducing time.
Further, since the DC power supply circuit has two DC power supply circuits of 5V and 24V, when the image forming apparatus shifts to the energy saving mode, it is not necessary to supply 24V voltage to the movable part including the motor and the solenoid. The control unit 51 may turn off the 24V voltage generation command signal. As a result, the 24 VDC power supply circuit 22 does not operate, and the loss of power consumption at all times in the power supply device 20 can be reduced to save energy.

Next, in the above-described embodiment, the case where two relays with one contact are used has been described. However, as shown in FIG. 6, a relay unit with two contacts that controls opening and closing of two contacts with one coil. Even when 40 'is used, the same operation as described above can be performed.
In this case, when the coil 46 of the coil portion 47 is energized, the opening and closing of the first relay contact portion 44 and the second relay contact portion 45 is controlled, and the other processes are the same as described above.
Further, the image forming apparatus having a plurality of interlock system DC power supply circuits can be implemented in the same manner as described above.

  For example, as illustrated in FIG. 7, the power supply device 20 ′ includes a 12 VDC power supply circuit 23 that supplies a 12 V voltage to the load unit 52 and a 24 VDC power supply circuit 24 that supplies a 24 V voltage. Supply and stop of the output 12V voltage is controlled by opening and closing the first relay contact portion 44 of the relay unit 40, and the 24V voltage output from the 24VDC power supply circuit 24 is controlled by opening and closing the second relay contact portion 45 of the relay unit 40. Supply and stop are controlled, and the control unit 51 ′ outputs an output on command as a 12 V / 24 V voltage generation command signal to each of the 12 VDC power circuit 23 and the 24 VDC power circuit 24 by the timer interrupt process similar to the above, and outputs 12 VDC. The voltage output of the power supply circuit 23 and the 24VDC power supply circuit 24 is performed, the output off command is output, and the 12VDC power supply circuit 2 Stopping the voltage output of 24VDC power supply circuit 24 and the other processes are the same as described above.

In this way, by using a relay in the interlock circuit, it is possible to prevent occurrence of inrush current when the relay contact is closed in consideration of the operation time of the relay contact, and welding of the relay contact due to the inrush current is achieved. It is possible to eliminate malfunction of the DC power supply circuit and malfunction of the CPU.
Further, since the voltage generation operation of the DC power supply circuit is turned off in conjunction with the opening and closing of the door of the image forming apparatus, the voltage generation operation is performed in a state where the door is open and power supply to the load portion side is unnecessary. As a result, it is possible to reduce power consumption loss and save energy.
Further, since the voltage generation command signal of the DC power supply circuit is determined and issued by the control unit, the voltage generation command signal can be turned off when the image forming apparatus shifts to the energy saving mode, so that the door is opened. Can save energy as well.
In addition, since sequence control is performed in which no inrush current occurs, the relay life due to welding of the relay contacts is not shortened, and the life of the relay can be extended.

This image forming device is not a method of increasing the voltage step by step while monitoring the power output to the load unit after waiting for a certain time after detecting the door closing in the control unit. Since it is turned on, the output of the power source can be started up in a shorter time after the door of the apparatus is closed, and the parts cost for that purpose can be reduced. Also, the software load can be reduced by a simple method.
In addition, the open / close detection of the device door is determined by the general-purpose control unit, not the open / close detection sensor, and the door open / close detection sensor is not required. be able to.

In the above-described embodiment, the case has been described in which the left door switch 30 and the right door switch 31 are turned on in conjunction with the left door and the right door of the front door 5 being closed and turned off when the front door 5 is opened. The switches may be turned off when both doors are closed and turned on when the doors are opened, and the relay unit may be switched in conjunction therewith.
Moreover, although the case where the drive voltage of the coil part of the relay part was 5V was shown, you may make it 24V and another voltage value.
In addition, one switch is provided for each of the left and right doors, and two of them are connected in series. However, if the door is one type of image forming apparatus, the door opening / closing detection means has only one switch. It is sufficient, and two switches may be provided in series with respect to one door in order to improve safety.
Furthermore, in the above-described embodiment, the case of the front door has been described, but the same can be applied to other doors including the toner cover.

  The image forming apparatus according to the present invention can be applied to all other image forming apparatuses including a facsimile machine and a printer.

FIG. 3 is a block diagram illustrating a configuration of a main part according to the present invention including a control unit of the image forming apparatus illustrated in FIG. 2. 1 is a diagram illustrating an example of an appearance of an image forming apparatus according to an embodiment of the present invention. It is a wave form diagram with which it uses for description of the electric power feeding control process of the power supply device 20 shown in FIG. FIG. 3 is a flowchart showing processing when a main power switch (main power SW) of the image forming apparatus shown in FIG. 2 is turned on.

It is a flowchart figure which shows the timer interruption process of the control part shown in FIG. It is a block diagram which shows the other structural example of the principal part which concerns on this invention including the control part of the image forming apparatus shown in FIG. FIG. 10 is a block diagram showing still another configuration example of a main part according to the present invention including a control unit of the image forming apparatus shown in FIG. 2.

Explanation of symbols

1: Contact glass 2: ADF 3: Operation section 4: Power subkey 5: Front cover 6: Paper feed tray 7: Main power switch 8: Toner cover 9: Finisher 10: Main body 20, 20 ': Power supply 21: 5VDC Power supply circuit 22, 24: 24VDC power supply circuit 23: 12VDC power supply circuit 30: Left door switch 31: Right door switch 40, 40 ': Relay part 41, 47: Coil part 42: First coil 43: Second coil 44: First 1 relay contact part 45: second relay contact part 46: coil 50: control device 51, 51 ': control part 52: load part 53: input terminal for 5V voltage detection

Claims (4)

A power supply device comprising different plurality of supply of the output voltage, a first switch for opening and closing a lower power output paths of the output voltage of the plurality of power supply by opening and closing the door includes a cover or door, opening and closing of the first switch A second switch that opens and closes an output path of a power supply having a high output voltage among the plurality of power supplies, and a control means that is connected to an output path downstream of the first switch,
When the control unit detects that the output from the output path downstream of the first switch is an output indicating the open state of the first switch when the door is opened, the output is stopped at the power source having the high output voltage. When the door is closed and the output from the output path downstream of the first switch is the output indicating the closed state of the first switch, the power is output to the power source having the high output voltage An image forming apparatus comprising means for starting the process. The detection time interval when the control means detects the output indicating the closed state of the first switch twice in succession is the operation time of opening / closing the first switch and the opening / closing of the first switch. The first total time obtained by adding up the bounce time until the fully opened state or the closed state during the operation, the open / close operation time of the second switch, and the fully open state during the open / close operation of the second switch The image forming apparatus according to claim 1 , wherein the time interval is equal to or greater than a larger total time of a second total time obtained by adding up bounce times until the closed state is reached . The detection time interval when the control means detects that the output indicates the open state of the first switch is complete when the first switch is opened and closed and when the first switch is opened and closed. The first total time obtained by adding up the bounce time until the switch is opened or closed, the opening / closing operation time of the second switch, and the opening / closing operation of the second switch. 3. The image forming apparatus according to claim 1 , wherein the time interval is equal to or greater than the larger total time of the second total time obtained by adding up the bounce time until the bounce . When the control means detects that the output indicates the closed state of the first switch, the detection time interval is completely the opening / closing operation time of the first switch and the opening / closing operation of the first switch. The first total time obtained by adding up the bounce time until the switch is opened or closed, the opening / closing operation time of the second switch, and the opening / closing operation of the second switch. the image forming apparatus according to any one of claims 1 to 3, characterized in that the total time over the time interval, whichever is greater and the second total time which is the sum of the bounce time until.

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