JP6026452B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus having a cover for maintenance inside the apparatus, and more particularly to an image forming apparatus having an interlock switch that detects opening and closing of the cover.

  In image forming devices such as printers and copiers, the cover for internal maintenance (replenishment of toner and paper jams) is provided with an interlock switch connected in series to the power line. In order to ensure, generally, control is performed so that the image forming operation is not performed when the cover is open (see, for example, Patent Document 1).

  In Patent Document 1, an interlock switch provided between the output control unit and the drive unit connects the output control unit and the drive unit when the cover is closed, and drives the cover open / close detection circuit when the cover is open. It is comprised so that a part may be connected. In addition, in the sleep mode, a minute power supply other than the power supplied to the drive unit is used in the cover open / close detection circuit so that the cover open / close detection can be performed even when the power supply to the drive unit is stopped in the sleep mode. It has become.

JP 2004-148724 A

  However, in the technique of Patent Document 1, when two covers are provided, and each of the two covers is provided with two interlock switches connected in series to the power supply line, When the interlock switch on the downstream side of the interlock switch is turned off, it is not possible to detect the on / off state of the upstream interlock switch, and it is impossible to detect the opening / closing of the cover. .

  The present invention has been made in view of the above points, and an object of the present invention is to reliably detect on / off of each of the two interlock switches connected in series to the power supply line without error. An object of the present invention is to provide an image forming apparatus capable of performing the above.

In order to solve such a problem, an image forming apparatus of the present invention is an image forming apparatus provided with a first cover and a second cover, which is turned on / off in response to opening / closing of the first cover, and is loaded when turned on. A first interlock switch that connects a power supply line to which power is supplied and a power supply voltage, and connects the power supply line to a detection voltage lower than the power supply voltage and at which the load does not operate, A second interlock switch that turns on and off the power supply line between the first interlock switch and the load in response to opening and closing of the second cover; the first interlock switch; and the second interlock switch; A first comparison means for comparing the voltage of the power line during a period with a set threshold, and before the second interlock switch and the load A second comparison means for comparing the voltage of the power supply line with the set threshold value, a threshold value setting means for setting the threshold value respectively used in the first comparison means and the second comparison means, and the first comparison Cover opening / closing detecting means for detecting opening / closing of each of the first cover and the second cover in accordance with a comparison result of the first comparing means and the second comparing means, wherein the threshold setting means is the first comparing means. The threshold value used is set to a first threshold value between the detection voltage and the power supply voltage in the normal mode, and to a second threshold value between 0 V and the detection voltage in the sleep mode, and the second comparison The threshold used by the means may be the second threshold when no jam is detected, between 0 V and the power supply voltage when a jam is detected, and at the load during jam processing. And setting each of that the electromotive force third threshold higher than the voltage of.
Furthermore, the image forming apparatus according to the present invention may further include a first cover locking unit that locks the first cover in a closed state when a jam is detected.

  According to the present invention, it is possible to reliably detect on / off of each of the two interlock switches connected in series to the power line without error, and to open / close each of the first cover and the second cover without error. There is an effect that it can be ensured.

1 is a schematic cross-sectional view showing an internal configuration of an embodiment of an image forming apparatus according to the present invention. FIG. 2 is an external perspective view showing a state where a first cover of the image forming apparatus shown in FIG. 1 is open. FIG. 2 is an external perspective view showing a state where a second cover of the image forming apparatus shown in FIG. 1 is open. FIG. 2 is a block diagram illustrating a schematic configuration of the image forming apparatus illustrated in FIG. 1. FIG. 2 is a block diagram illustrating a configuration of a cover open / close detection unit in the image forming apparatus illustrated in FIG. 1. It is a table | surface which shows the judgment result by the control part shown in FIG.

Next, embodiments of the present invention will be specifically described with reference to the drawings.
Referring to FIG. 1, the image forming apparatus according to the present embodiment forms four images corresponding respectively to different four color C (cyan), M (magenta), Y (yellow), and K (black) color image data. The color printer 1 is provided with sections 10a, 10b, 10c, and 10d. An intermediate transfer belt 20 is provided adjacent to the upper parts of the four image forming units 10a, 10b, 10c and 10d.

  Referring to FIG. 2, a first cover 40 is provided on the upper surface of the color printer 1, and the upper portion of the intermediate transfer belt 20 is opened by opening the first cover 40, and toner containers 50 a, 50 b, 50 c. And 50d are in a detachable state. The toner containers 50a, 50b, 50c, and 50d include four colors C (cyan), M (magenta), Y (yellow), and K (black) supplied to the four image forming units 10a, 10b, 10c, and 10d, respectively. Toner is contained. 2 is a display unit such as a liquid crystal display on which the state of the color printer 1 is displayed, and 4 is an operation unit that receives various instructions from the user. Further, as shown in FIG. 1, the first cover 40 includes a first interlock switch 80 that is turned on and off by opening and closing the first cover 40, and a first cover lock portion that locks the first cover 40 in a closed state. 81 is provided. The first interlock switch 80 is turned off when the first cover 40 is opened, and is configured to cut off the power supply voltage supplied to each component of the color printer 1. Moreover, as the 1st cover lock part 81, the linear actuator which advances / retreats the rod 81a can be used, for example. In this case, the first cover 40 is locked by moving the rod 81a forward and inserting the rod 81a into the opening 40a (see FIG. 2) provided in the first cover 40.

  The four image forming units 10a, 10b, 10c, and 10d are respectively provided with photosensitive drums 11a, 11b, 11c, and 11d that carry visible images (toner images) of the respective colors. Around the photosensitive drums 11a, 11b, 11c, and 11d, charging devices 12a, 12b, 12c, and 12d for charging the photosensitive drums 11a, 11b, 11c, and 11d, and the photosensitive drums 11a, 11b, 11c, and 11d, respectively. Respectively, an exposure unit 13 for exposing image information, developing devices 14a, 14b, 14c and 14d for forming toner images on the photosensitive drums 11a, 11b, 11c and 11d, and photosensitive drums 11a, 11b, 11c and A primary transfer roller 15a, 15b, 15c and 15d for transferring the toner image on 11d to the intermediate transfer belt 20, respectively, and a cleaning device for removing the developer (toner) remaining on the photosensitive drums 11a, 11b, 11c and 11d. 16a, 16b, 16c and 16d are provided. That.

  The toner images formed on the photosensitive drums 11a, 11b, 11c, and 11d are sequentially transferred onto the intermediate transfer belt 20 that moves while contacting the photosensitive drums 11a, 11b, 11c, and 11d. The toner images sequentially transferred onto the intermediate transfer belt 20 are transferred onto the recording paper P at a time by the secondary transfer roller 17. The recording paper P is accommodated in a paper cassette 30 disposed in the lower part, and is conveyed through the recording paper conveyance path 33 to the secondary transfer roller 17 via the paper feed roller 31 and the registration roller 32. The toner image transferred onto the recording paper P is fixed on the recording paper P by the fixing device 18, and the printed recording paper P passes through the recording paper conveyance path 33 and is discharged onto the first cover 40 by the discharge roller 34. To be discharged.

  Referring to FIG. 3, a second cover 41 is provided on the side surface on which the recording paper conveyance path 33 is disposed, and the recording paper conveyance path 33 is opened by opening the second cover 41. It is configured. Thereby, the paper jam of the recording paper P in the recording paper conveyance path 33 can be eliminated. Further, as shown in FIG. 1, the second cover 41 is provided with a second interlock switch 82 that is turned on and off by opening and closing the second cover 41. The second interlock switch 82 is turned off when the second cover 41 is opened, and is configured to cut off the power supply voltage supplied to each component of the color printer 1.

  FIG. 4 is a block diagram illustrating a schematic configuration of the color printer 1. The color printer 1 includes a control unit 3 connected to a communication unit 60, a storage unit 70, and a jam detection unit 71. The control unit 3 is an information processing unit such as a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The ROM stores a control program for controlling the operation of the image forming apparatus. The control unit 3 reads out a control program stored in the ROM and develops the control program in the RAM, thereby responding to predetermined instruction information input from the operation unit 4 and a print job received by the communication unit 60. A series of image forming operations are realized by controlling each component (image forming units 10a, 10b, 10c and 10d, exposure unit 13, fixing device 18, intermediate transfer belt 20 and the like). Further, the control unit 3 switches from the normal mode to the sleep mode as power control for reducing power consumption when there is no user instruction input from the operation unit 4 or an instruction to start an image forming operation and a predetermined time has elapsed. Transition. In the sleep mode, the control unit 3 controls a power supply circuit (not shown), turns off the power supply voltage supplied to each component that realizes the image forming operation, and some standby components such as the CPU of the control unit 3 Is supplied with a voltage sufficiently lower than the power supply voltage.

  The communication unit 60 has a function of transmitting and receiving various data to and from a peripheral device 62 such as a personal computer via a network 61 such as a LAN, and includes print data used for image formation such as color image data. A job is received from the peripheral device 62.

  The storage unit 70 is a storage unit such as a semiconductor memory or an HDD (Hard Disk Drive), and is a storage unit in which print data such as color image data received by the communication unit 60 is accumulated.

  The jam detection unit 71 includes a recording paper detection sensor that detects the recording paper P conveyed through the recording paper conveyance path 33, and the recording paper P is detected by the recording paper detection sensor for a predetermined time or a predetermined timing. When the recording paper P is not detected in step S1, a jam (paper jam) of the recording paper P is detected, and a jam detection signal is notified to the control unit 3.

  A first cover lock unit 81 is connected to the control unit 3. When the jam detection signal is notified from the jam detection unit 71, the control unit 3 causes the first cover lock unit 81 to lock the first cover 40 in the closed state. The lock of the first cover 40 by the first cover lock unit 81 may be maintained until the jam of the recording paper P is eliminated, or may be configured to be released by the operation unit 4.

  Further, the control unit 3 is connected to a first comparison unit 83 and a second comparison unit 84 that compare the voltages of the power supply lines, and a threshold setting unit 85. The control unit 3 functions as cover opening / closing detection means for detecting opening / closing of the first cover 40 and the second cover 41 in accordance with outputs from the first comparison unit and the second comparison unit 84, and a detection result as necessary. Is displayed on the display unit 2 to notify the user.

  The threshold setting unit 85 is a threshold setting unit that sets a threshold to be compared with the voltage of the power supply line in the first comparison unit 83 and the second comparison unit 84 based on an instruction from the control unit 3. The threshold value at 83 is switched between the normal mode and the sleep mode, and the threshold value at the second comparison unit 84 is switched between when the jam is not detected and when the jam is detected.

  Referring to FIG. 5, a first interlock switch 80 and a second interlock switch 82 are connected in series to a power supply line that supplies power from a power supply voltage to a load (motor, heater, etc.) 90 of each part. Thereby, when both or one of the first cover 40 and the second cover 41 is open, at least one of the first interlock switch 80 and the second interlock switch 82 is turned off, and the power supply When the supply of the voltage to each part of the load 90 is interrupted and both the first cover 40 and the second cover 41 are closed, either the first interlock switch 80 or the second interlock switch 82 is used. Is turned on, and the power supply voltage is supplied to the load 90 of each part.

  The first interlock switch 80 is a one-circuit two-contact switch disposed upstream of the second interlock switch 82, and a power supply voltage is applied to a contact connected when the first cover 40 is closed, A detection voltage is connected to each contact point that is connected when the first cover 40 is open, via a backflow prevention diode. Thus, when the first cover 40 is closed, the power supply voltage is supplied to the power supply line, and when the first cover 40 is open, the detection voltage is supplied to the power supply line. The detection voltage is a voltage that is sufficiently lower than the power supply voltage and does not operate the load 90. For example, a voltage supplied to the CPU of the control unit 3 during sleep is used. In this embodiment, it is assumed that 24V is supplied as the power supply voltage and 3.3V is supplied as the detection voltage.

The first comparator 83 is set by the voltage Va of the power line between the first interlock switch 80 and the second interlock switch 82 (hereinafter referred to as switch-switch power line) and the threshold setting unit 85. And the comparison result is output to the control unit 3.
The second comparison unit 84 also includes a voltage Vb of a power line between the second interlock switch 82 and the load 90 (hereinafter referred to as a switch-to-load power line), and a threshold set by the threshold setting unit 85. And the comparison result is output to the control unit 3.

  Referring to FIG. 5, the first comparison unit 83 is non-inverted at the connection point between the resistor R1 and the resistor R2 connected in series between the switch-to-switch power line and the ground terminal, and the resistor R1 and the resistor R2. It can be configured by a comparator U1 to which an input terminal is connected and an output terminal is connected to the control unit 3. The second comparison unit 84 includes a resistor R3 and a resistor R4 connected in series between the switch-load power supply line and the ground terminal, and a non-inverting input terminal connected to a connection point between the resistor R3 and the resistor R4. And a comparator U 2 whose output terminal is connected to the control unit 3. In this case, the threshold setting unit 85, based on an instruction from the control unit 3, the voltage input to the inverting input terminal of the comparator U1 in the first comparison unit 83 and the comparator U2 in the second comparison unit 84. And a DAC (D / A converter) that respectively generates a voltage input to the inverting input terminal.

  In the normal mode, the threshold setting unit 85 sets the threshold to be compared with the voltage Va of the switch-to-switch power supply line in the first comparison unit 83 to the first threshold set to a voltage between the detection voltage and the power supply voltage. To do. Thus, in the normal mode, the first comparison unit 83 compares the voltage Va of the switch-to-switch power line with the first threshold value, and when the voltage Va is higher than the first threshold value, the high level signal. When the voltage Va is lower than the first threshold, a low level signal is output to the control unit 3. Referring to FIG. 6, in the normal mode, the voltage Va of the switch-to-switch power line is 24V which is the power supply voltage when the first cover 40 is closed, and the detection voltage when the first cover 40 is opened. It becomes 3.3V. Therefore, when the high level signal is input from the first comparison unit 83 in the normal mode, the control unit 3 detects that the first cover 40 is closed, and the low level signal from the first comparison unit 83. Is input, it is detected that the first cover 40 is open.

  In the sleep mode, the threshold setting unit 85 sets the threshold to be compared with the voltage Va of the switch-to-switch power line in the first comparison unit 83 to a second threshold set to a voltage between 0 V and the detection voltage. . Thus, in the sleep mode, the first comparison unit 83 compares the voltage Va of the switch-to-switch power line with the second threshold value, and when the voltage Va is higher than the second threshold value, the high level signal. When the voltage Va is lower than the second threshold, a low level signal is output to the control unit 3. Referring to FIG. 6, in the sleep mode, the voltage Va of the switch-to-switch power line is 0 V (power supply voltage in the sleep mode) when the first cover 40 is closed, and the first cover 40 is open. And the detected voltage is 3.3V. Therefore, when the low level signal is input from the first comparison unit 83 in the sleep mode, the control unit 3 detects that the first cover 40 is closed, and the high level signal from the first comparison unit 83. Is input, it is detected that the first cover 40 is open.

  Regardless of whether the mode is the normal mode or the sleep mode, when the jam detection unit 71 does not detect a jam of the recording paper P, the threshold setting unit 85 switches the switch-load in the second comparison unit 84. The threshold value to be compared with the voltage Vb of the intermediate power supply line is set to a second threshold value set to a voltage between 0 V and the detection voltage. As a result, when no jam is detected, the second comparison unit 84 compares the voltage Vb of the switch-to-load power supply line with the second threshold, and when the voltage Vb is higher than the second threshold, the high level When the signal has a voltage Vb lower than the second threshold, a low level signal is output to the control unit 3. Referring to FIG. 6, in the normal mode, when the second cover 41 is open, the voltage Vb of the switch-to-load power line is 0 V regardless of whether the first cover 40 is open or closed, and the second cover 41 is closed. When the first cover 40 is opened and closed, the power supply voltage becomes 24 V or the detection voltage 3.3 V. Therefore, when the high level signal is input from the second comparison unit 84 in the normal mode, the control unit 3 detects that the second cover 41 is closed, and the low level signal from the second comparison unit 84. Is input, it is detected that the second cover 41 is open.

  In the sleep mode, as shown in FIG. 6, the voltage Vb of the switch-to-load power supply line is set to 0 V when the first cover 40 is closed, regardless of whether the second cover 41 is opened or closed. Is opened and the second cover 41 is closed, the detection voltage is 3.3 V. When the first cover 40 is opened and the second cover 41 is opened, the voltage is 0 V. Therefore, in the sleep mode, the control unit 3 inputs a high level signal from the second comparison unit 84 only when the input from the first comparison unit 83 is a high level signal and the first cover 40 is open. Then, it is detected that the second cover 41 is closed. When a low level signal is input from the second comparison unit 84, it is detected that the second cover 41 is open.

  When the load 90 is a motor, when the jam detection unit 71 detects a jam of the recording paper P, the motor is rotated by the jam processing of the recording paper P, an electromotive force is generated at the load 90, and the switch-load The voltage Vb of the intermediate power line may exceed the second threshold value. In other words, the second threshold value is a low voltage between 0 V and the detection voltage at which the load 90 does not operate. Therefore, when the second comparison unit 84 compares the voltage Vb of the switch-to-load power supply line with the second threshold value, the second cover 41 that opens the recording sheet conveyance path 33 is opened, and the recording sheet P is jammed. In this case, a high level signal is input from the second comparison unit 84 to the control unit 3 due to the electromotive force generated in the load 90, and it may be erroneously detected that the second cover 41 is closed.

  Therefore, in the present embodiment, at the time of detecting a jam, the control unit 3 locks the first cover 40 in the closed state by the first cover lock unit 81, and the threshold setting unit 85 switches the switch in the second comparison unit 84. The threshold value to be compared with the voltage Vb of the inter-load power supply line is set to a third threshold value that is a voltage between 0 V and the power supply voltage and is equal to or higher than the electromotive force voltage that is likely to be generated in the load 90 during jam processing. Thereby, at the time of jam detection, the second comparison unit 84 compares the voltage Vb of the power line between the switch and the load with the third threshold value, and when the voltage Vb is higher than the third threshold value, the High level signal When the voltage Va is lower than the third threshold, a low level signal is output to the control unit 3. Referring to FIG. 6, when the jam is detected, the first cover 40 is locked in the closed state, so that the voltage Vb of the power line between the switch and the load is 0 V when the second cover 41 is open, When 41 is closed, the power supply voltage becomes 24V. Therefore, when the high level signal is input from the second comparison unit 84 in the normal mode, the control unit 3 detects that the second cover 41 is closed, and the low level signal from the second comparison unit 84. Is input, it is detected that the second cover 41 is open. Since the third threshold is set to be equal to or higher than the voltage of the electromotive force that is likely to be generated in the load 90, a high level signal is output from the second comparison unit 84 due to the electromotive force generated in the load 90 during jam processing. It is possible to prevent erroneous detection that the second cover 41 is closed without being input to the control unit 3. Further, the third threshold value and the first threshold value may be shared.

  In the present embodiment, the first interlock switch 80 is provided on the first cover 40 that opens and closes the upper portion, but the cover on which the first interlock switch 80 is provided is not limited and can be opened and closed even in the sleep mode. The first interlock switch 80 may be provided on the cover to be detected.

  As described above, according to the present embodiment, the first cover 40 is turned on / off according to the opening / closing of the first cover 40. When the first cover 40 is turned on, the switch-switch power line is connected to the power supply voltage. A first interlock switch 80 that connects a power supply line and a detection voltage that is lower than the power supply voltage and at which the load 90 does not operate, and a second interlock that turns on and off the power line between the switch and the load according to opening and closing of the second cover 41 The switch 82, the first comparison unit 83 that compares the voltage Va of the switch-to-switch power line and the set threshold value, and the second comparison that compares the voltage Vb of the switch-to-load power line and the set threshold value Unit 84, threshold setting unit 85 for setting thresholds used in first comparison unit 83 and second comparison unit 84, first comparison unit 83 and And a control unit 3 that detects the opening and closing of the first cover 40 and the second cover 41 according to the comparison result of the second comparison unit 84, and the threshold setting unit 85 sets the threshold used by the first comparison unit 83. In the normal mode, a first threshold value between the detection voltage and the power supply voltage is set to a second threshold value between 0 V and the detection voltage in the sleep mode. It is configured to set a second threshold value at the time of non-detection, a third threshold value between 0 V and the power supply voltage at the time of jam detection, and higher than the voltage of the electromotive force that is likely to be generated at the load 90 at the time of jam processing. Has been. With this configuration, each of the two first interlock switches 80 and the second interlock switch 82 connected in series to the power supply line can be reliably detected without error, and the first cover 40 and the second cover There is an effect that each of the two covers 41 can be reliably opened and closed without error. Furthermore, since the third threshold is set to be equal to or higher than the voltage of the electromotive force that is feared to be generated at the load 90, a high level signal is output from the second comparison unit 84 due to the electromotive force generated at the load 90 during jam processing. It is possible to prevent erroneous detection that the second cover 41 is closed without being input to the control unit 3.

  Furthermore, according to the present embodiment, the first cover lock portion 81 that locks the first cover in the closed state when a jam is detected is provided. With this configuration, when the jam is detected, the first cover is surely closed, and even if the threshold used by the second comparison unit 84 is set to the third threshold, the opening / closing of the second cover 41 is reliably detected. Can do.

  Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Color printer 2 Display part 3 Control part 4 Operation part 10a, 10b, 10c, 10d Image formation part 11a, 11b, 11c, 11d Photosensitive drum 12a, 12b, 12c, 12d Charging device 13 Exposure unit 14a, 14b, 14c, 14d Developing device 15a, 15b, 15c, 15d Primary transfer roller 16a, 16b, 16c, 16d Cleaning device 17 Secondary transfer roller 18 Fixing device 20 Intermediate transfer belt 30 Paper cassette 31 Paper feed roller 32 Registration roller 33 Recording paper transport path 34 Discharge roller 40 First cover 40a Opening 41 Second cover 50a, 50b, 50c, 50d Toner container 60 Communication unit 70 Storage unit 71 Jam detection unit 80 First interlock switch 81 First cover lock unit 81a Rod 82 Second interlock switch 83 First comparison unit 84 Second comparison unit 85 Threshold setting unit 90 Load

Claims (2)

An image forming apparatus provided with a first cover and a second cover,
A power supply line that is turned on and off according to the opening and closing of the first cover and that supplies power to the load when connected is connected to a power supply voltage, and the load is lower than the power supply line and the power supply voltage to turn off the load. A first interlock switch for connecting a non-operating detection voltage;
A second interlock switch that turns on and off the power line between the first interlock switch and the load in response to opening and closing of the second cover;
A first comparing means for comparing a voltage of the power line between the first interlock switch and the second interlock switch with a set threshold;
A second comparing means for comparing a voltage of the power line between the second interlock switch and the load with the set threshold;
Threshold value setting means for setting the threshold values respectively used in the first comparison means and the second comparison means;
A cover open / close detecting means for detecting opening / closing of each of the first cover and the second cover according to a comparison result of the first comparing means and the second comparing means;
The threshold value setting means sets the threshold value used in the first comparison means to a first threshold value between the detection voltage and the power supply voltage in the normal mode, and a first threshold value between 0 V and the detection voltage in the sleep mode. The threshold used by the second comparing means is set to the second threshold when no jam is detected, between 0 V and the power supply voltage when a jam is detected, and at the load during jam processing. An image forming apparatus characterized in that each of the third threshold values is set to be higher than a voltage of an electromotive force at which generation is a concern.   2. The image forming apparatus according to claim 1, further comprising first cover locking means for locking the first cover to a closed state when a jam is detected.

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