JP2005121681A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply power stably and efficiently even in an image forming apparatus having a large power consumption. Further, erroneous determination of abnormality of the power control element due to connection of the power cord at that time is eliminated.
A main power cord 1 and a sub power cord 16 are provided as power cords for supplying AC power to the image forming apparatus. From the main power cord 1, a central control device 9 and the like mainly DC load system are provided. The sub power cord 16 supplies power to an AC load with high power consumption such as the fixing heater 15. Further, even when the central control circuit 9 that operates with the power from the main power cord 1 receives an abnormality signal from the SSR abnormality detection circuit 11, the AC power detection circuit 19 detects that no power is supplied by the sub power cord 16. In this case, it is not determined that the SSR 14 is abnormal, and a display prompting the connection of the sub power cord 16 is displayed.
[Selection] Figure 1

Description

  The present invention relates to an image forming apparatus having a plurality of AC input terminals.

Conventionally, the power consumption of an image forming apparatus main body excluding accessories such as a DF (document feeding apparatus) connected to the image forming apparatus and a sorter and a finisher is about several kW, and many general apparatuses are single. Electric power was supplied from one AC input terminal. (For example, see Patent Document 1)
Also, conventionally, in the image forming apparatus, the runaway of the fixing device has led to overheating of the fixing heater. Before this problem occurs, a short-circuit detection mechanism for the AC power control element of the fixing device heater can be prevented in advance. It has. (For example, see Patent Document 2)
The AC power control element short-circuit detection mechanism is a mechanism in which the control mechanism detects whether or not AC voltage is generated at both ends of the heater AC power control block when the heater is OFF.

  This is because when the control mechanism commands the heater of the fuser to be turned off, the AC power control element is normally opened, thereby inevitably generating an AC voltage across the AC power control block.

When the command logic of the control mechanism and the AC voltage logic contradict each other at both ends of AC power control inhibition, this problem is given top priority and the operation of the image forming apparatus is completely stopped and the user is informed. This mechanism prevents the occurrence of this problem from being canceled.
JP 2000-23354 A Japanese Patent Laid-Open No. 05-100603

  However, with the recent increase in speed and functionality, the image forming apparatus has become larger and the power consumption has increased, making it difficult to supply power to the apparatus with a conventional single AC input terminal. In this case, there are methods to deal with by increasing the current and voltage while maintaining single-phase power, or changing the power from single-phase to three-phase, but in either case the AC input terminal or AC code is changed and the device is installed. The scale of change of the electrical equipment in the place to be performed is large, which is an adverse effect of device replacement.

  Further, as described above, since the malfunction of the AC power control element of the fixing unit is given the highest priority in the entire apparatus, the user does not return it. Therefore, until the service person arrives, A decrease in productivity occurs.

  In order to solve the above problems, an image forming apparatus of the present invention includes a control unit that controls the operation of a load, a fixing unit that fixes an unfixed image formed on a recording medium by a first heating source, and the control. A DC power source for supplying power to the unit, a first AC input terminal for supplying AC power to the DC power source, and a second AC input terminal for supplying AC power to the first heating source. It is characterized by having.

  According to another aspect of the present invention, there is provided an image forming apparatus that stops an operation of the apparatus upon detecting an abnormality of an element that controls an operation of a load. Power is supplied from a first AC input terminal among the AC input terminals, and a central control circuit that controls the entire image forming apparatus, and power supply from a second AC input terminal among the plurality of AC input terminals. A power control element that controls and controls driving of the load, and an abnormality detection circuit that detects an abnormality of the power control element, and the central control circuit detects an abnormality of the power control element by the abnormality detection circuit. When detected, it is not determined that the power control element is abnormal when the second AC input terminal is not connected to an AC power source.

  According to the first aspect of the present invention, changes in the electrical equipment at the installation location of the apparatus are reduced, and an increase in power consumption of the apparatus can be handled.

  According to the fourth aspect of the present invention, in the image forming apparatus having a plurality of power cords, when the abnormality of the power control element is detected, it is determined whether the second power cord is connected or not. By determining the operation of the image forming apparatus, it is possible to prevent erroneous determination of abnormality of the power control element and to prevent the image forming apparatus from becoming inoperable even after the power cord is connected.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an image forming apparatus to which the present invention can be applied. This image forming apparatus is characterized by having a plurality of power cords. In this embodiment, the power supply cord has two power cords, but the present invention can be applied even when there are three or more power cords.

  In FIG. 1, reference numeral 1 denotes a main power cord which is a first AC input terminal, and a first ground leakage breaker 2 and a first line filter 3 are arranged downstream thereof.

  When the first AC input terminal 1 is connected to an AC power source, power is immediately supplied to the four night-time power sources. There are two systems, namely, a system in which power is supplied through the night-time switch SW12 and a system in which power is supplied immediately without going through the night-time switch SW12. The night-time power supply 4 is activated when the two systems of power are supplied together.

  When the night-time power supply 4 is activated and the DC power VCCA is output, it is supplied to the central control unit 9 that controls the entire image forming apparatus, and the central control unit 9 starts to operate, and the first solid state 7 The relay SSR (including triac) is controlled to control 8 drum heaters and 24 cassette heaters. In addition, power is supplied to the night-time DC load 25 controlled by the central control unit 9.

  Further, when the user turns on 6 main switches provided in the apparatus casing, 5 main power supplies are activated, and DC power VCCR is output, so that the operation display unit 21, main system DC load 22, and high voltage power supply are output. 23 is supplied with electric power. As a result, half of the image forming apparatus can be operated.

  Reference numeral 16 denotes a sub power cord which is a second AC input terminal, and 10 second leakage breakers and 17 second line filters are provided downstream thereof. 13 is an AC relay for safety, and 18 controllers control ON / OFF of the relay.

  This apparatus is configured to be able to detect on / off of the main switch SW6 by the central control unit 9. When the central control unit 9 detects the on of the main switch SW6, the operation / display unit 21, the main system DC load, and The high voltage power source 23 is controlled, and further, an SSR group 14 for controlling the fixing heater 15 to be described later is controlled, and the driving of the fixing heater 15 is started.

  If the night switch SW12 is opposite to the contact state shown in FIG. 1, power is supplied to the night power source 4 in synchronization with the main switch SW6 being turned on, and the night power source 4 is activated. Then, DC power VCCA is supplied to the central controller 9.

  The line system of the main switch SW6 is connected to a document illumination lamp 20 and a lamp regulator CVR19 for controlling the lighting voltage of the document illumination lamp 20, and power can be supplied in synchronization with the main switch SW6 being turned on. The central controller 9 controls the lamp regulator CVR19.

  The central control unit 9 is connected to an environmental SSR abnormality detection unit 26 that monitors the abnormality of the first solid state relay (SSR) group 7. When the central control unit 9 detects the SSR abnormality signal from the environmental SSR abnormality detection unit 26, the central control unit 9 turns off the environmental AC relay 27 and turns off the supply of AC power to the drum heater 8 and the cassette heater 24. Here, AC power to the drum heater 8 and the cassette heater 24 is configured to be supplied from the same first AC input terminal 1 as the night power supply 4 that supplies power to the central control unit 9. As a result, the environment SSR abnormality detection unit 26 does not detect the abnormality of the environment SSR 7 regardless of which of the first AC input terminal 1 and the second AC input terminal 16 is supplied with power first. When power is supplied from the first AC input terminal 1 regardless of the AC power supply sequence of the AC input terminal 1 and the second AC input terminal 16, the central controller 9 causes the drum heater 8 and the cassette heater 24 to operate normally. To be operated.

  As a result, the night-time power supply 4 and the main power supply 5 of the image forming apparatus, the central control unit 9, the AC controller 18, the operation / display unit 21, and the power supplied from the power supply and each load can be operated.

  Reference numeral 16 denotes a second power supply cord (sub power supply cord) which is a second AC input terminal, and 10 second earth leakage breakers and 17 second line filters are provided downstream thereof.

  Reference numeral 13 denotes a fixing AC relay for shutting off the AC power supply to the fixing heater 15 for safety protection when the fixing heater 15 is abnormal, which will be described later. An ON / OFF of the relay is controlled by an 18 AC controller.

  The AC controller 18 controls the SSR group 14 based on a command from the central control unit 9 to perform on / off control of the power supplied to the fixing heater 15, or from the fixing SSR abnormality detecting unit 11 that monitors SSR abnormality. The SSR state is transmitted to the central control unit 9.

  Under normal conditions, the fixing AC relay 13 is maintained in the ON state under the control of the AC controller 18, and the power from the second AC input terminal is supplied to the 14th second SSR group (including the triac). By this SSR group 14, 15 fixing heater groups can be driven. The heaters used here are an upper heater and a lower heater for heating upper and lower rollers for heating and pressing a fixing unit (not shown), and an external heater for heating an external heating roller for heating the upper roller. is there.

  As described above, since the portion that receives power supply from the second AC input terminal can operate, the entire image forming apparatus can operate including the operation of the portion that receives power supply from the first AC input terminal. Become.

  A configuration distributed to the first AC input terminal 1 and the second AC input terminal 16 will be described. When the overall power of the image forming apparatus becomes enormous, it is impossible to supply necessary power with a single power cord. Therefore, a plurality of power cords are provided, and necessary power is supplied by connecting each to an AC power source. The fixing heater group 15 is the maximum power consumption part in this image forming apparatus. The fixing unit is a single unit, and the other control mechanism, the low-power drum heater 8 and the cassette heater 24 are a single unit. By dividing, efficient power supply control from two power cords becomes possible.

  In addition, the fixing heater group 15 is supplied with power through the second AC input terminal 16 and the first AC input terminal 1 of the night power supply 4 that supplies power to the central control unit 9 is separated from the AC supply system. Even when no power is supplied to either the first AC input terminal or the second AC input terminal, there is no adverse effect from the viewpoint of the operation and safety of the apparatus main body.

  FIG. 2 shows the relationship between the power supply state to the AC input terminal and the main body operation. When no AC power is supplied to either the first AC input terminal or the second AC input terminal, all operations in the apparatus are not performed.

  When power is not supplied to the first AC input terminal and power is supplied only to the second AC input terminal, both the night-time power supply 4 and the main power supply 5 are turned off, the central control unit 9 cannot be activated, and the operation of the apparatus Is not done. At this time, the AC relay 13 is turned off because the main power source 5 is turned off, and the SSR group 14 is also turned off because the AC controller 18 is turned off, so that the fixing system heater 15 is not supplied with power.

  When power is supplied to the first AC input terminal and power is not supplied to the second AC input terminal, the night power supply 4 and the main power supply 5 are turned on, the central control unit 9 and the AC controller 18 are activated, and the device Although the operation display unit 21, the DC load systems 22 and 25, and the high voltage load 23 can be operated, AC power is not supplied to the fixing system heater 15. As a result, the AC controller 18 detects the SSR abnormality from the fixing SSR abnormality detection unit 11 and transmits it to the central control unit 9, and the central control unit 9 stops the operation of the apparatus. The control in this case will be described later.

  When power is supplied to both the first AC input terminal and the second AC input terminal, power is supplied to the entire apparatus, and it starts normally and starts normal operation.

  As a result, the change in the electrical equipment at the installation location of the apparatus is reduced, the power consumption of the apparatus can be increased, and the AC load system and the DC load system are separated, so that the first AC input terminal and the second AC input terminal are separated. Power balance is relatively easy.

  Next, a description will be given of when power supply abnormality is detected.

  FIG. 3 is a block diagram showing the fixing unit in the block diagram of FIG. 1, and 11 SSR abnormality detection circuits for monitoring each SSR of the second SSR group 14 are connected. When the abnormality detection circuit 11 detects an abnormality in the SSR group 14, the controller 10 notifies the controller 10 of the information, and the controller 10 notifies the central control device 9 and cuts off the AC relay 13 as well as the operation of the entire image forming apparatus. Stop. The user is prohibited from returning from this state with an emphasis on safety until the cause of the abnormality is resolved.

  The operation of this abnormality detection circuit 11 will be described. FIG. 4 is an explanatory diagram of the operation of the abnormality detection circuit 11. The abnormality detection circuit 11 measures the output terminal voltage of the SSR 14 with respect to the input signal to the SSR 14.

  The abnormality detection circuit 11 detects an abnormality based on a combination of the SSR output terminals and the SSR on / off signal. FIG. 5 shows a truth table for explaining SSR operation abnormality detection. Four types of combinations of whether or not voltage is generated between SSR output terminals are defined for the SSRON / OFF signal that is an input of the SSR 14.

  In number 1, when the SSR is OFF, the SSR is in an open state, so that an AC voltage is generated at the output terminal of the SSR, resulting in normal operation.

  On the other hand, in the case of No. 2, when the SSR is set to OFF but no AC voltage is generated at the output terminal of the SSR, the SSR has failed in the short mode. In this state, a voltage is generated at both ends of the fixing heater 15, and the fixing heater 15 is continuously generating heat without being controlled by the SSR.

  In No. 3, when the SSR is set to ON and the AC voltage is generated at the SSR output terminal, the SSR is broken in the open mode.

  In No. 4, since the SSR is set to ON and the SSR is in a conductive state, no voltage is generated at the SSR output terminal, resulting in a normal operation.

  Returning to the block diagram of FIG. When central controller 9 receives a report of an SSR abnormality from controller 18, central controller 9 detects the presence or absence of power from the second AC input terminal by 28 AC power supply detection circuits. Here, if there is no AC input from the second AC input terminal, all the SSR output terminals in the truth table of FIG. Thereby, it corresponds to the state of number 2 in the truth table, and it is determined that the element is short-circuited. However, in actuality, the element is not abnormal, and there is no power supply from the second power cord.

  Therefore, when the central controller 9 detects that there is no AC input from the second AC input terminal based on the information of the AC power supply detection circuit 28, the central controller 9 does not determine that the SSR element is short-circuited.

  Further, the central control device issues a warning to the user that the second AC input terminal 16 is not properly mounted on the operation display unit 21 of the image forming apparatus, and connects the second AC input terminal to the AC power source. Prompt.

  As a result, it is possible to prevent the central control unit from erroneously detecting an abnormality in the SSR when only the first power cord is connected to the AC power source and the second power cord is not connected. It is possible to prevent the inconvenience that the device does not move even if connected.

1 is a block diagram showing an entire image forming apparatus to which the present invention can be applied. The figure explaining the relationship between each AC power supply normal state and device operation 1 is a block diagram showing the configuration of the fixing unit in FIG. Explanatory drawing of operation | movement of the SSR abnormality detection part of FIG. The figure which shows the truth table for demonstrating the abnormal operation | movement detection of SSR of FIG.

Explanation of symbols

1 First AC input terminal (main power cord)
4 Night power 5 Main power 6 Main switch 7 1st SSR
9 Central Control Unit 11 Fixing SSR Abnormality Detection Unit 13 Fixing AC Relay 14 Second SSR Group 15 Fixing Heater Group 16 Second AC Input Terminal (Sub Power Cord)
18 AC controller

Claims (7)

A control unit for controlling the operation of the load;
A fixing unit for fixing an unfixed image formed on the recording medium by a first heating source;
A DC power source for supplying power to the control unit;
A first AC input terminal for supplying AC power to the DC power source;
A second AC input terminal for supplying AC power to the first heating source;
An image forming apparatus comprising:   A second heating source controlled by the control unit and provided at a different location from the fixing unit is provided, and AC power from the first AC input terminal is supplied to the second heating source. The image forming apparatus according to claim 1.   It has a main switch independent of the AC power supply to the second heating source, and the power supply to the first heating source is controlled by the control unit in response to turning on of the main switch. The image forming apparatus according to claim 2. In the image forming apparatus that stops the operation of the apparatus when detecting an abnormality of the element that controls the operation of the load,
A plurality of AC input terminals each connected to an AC power source;
A central control circuit that is supplied with power from a first AC input terminal of the plurality of AC input terminals and controls the entire image forming apparatus;
A power control element that controls power supply from a second AC input terminal of the plurality of AC input terminals and controls driving of a load;
An abnormality detection circuit for detecting an abnormality of the power control element;
And the central control circuit detects the abnormality of the power control element by the abnormality detection circuit, and the second AC input terminal is not connected to an AC power source when the abnormality is detected in the power control element. An image forming apparatus characterized in that it is not determined to be abnormal.   When the abnormality detection circuit detects an abnormality of the power control element, the central control circuit connects the second AC input terminal to an AC power supply when the second AC input terminal is not connected to an AC power source. The image forming apparatus according to claim 4, wherein a display prompting connection to a power source is performed.   The image forming apparatus according to claim 4, wherein the abnormality detection circuit determines an abnormality based on an on / off signal of the power control element and an output voltage of the power control element. In an image forming apparatus having a plurality of AC input terminals connected to an AC power source,
An AC input terminal of a power source that operates a central control mechanism that controls the entire image forming apparatus and an AC input terminal that is used as heater power in a fixing mechanism of the image forming apparatus are separated, and A mechanism having both a failure detection mechanism of the AC power control element of the heater in the fixing device mechanism and a detection mechanism of whether or not the AC input terminal is mounted on the AC power source for receiving the heater power in the fixing device mechanism. An image forming apparatus.

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