JP2007147844A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of automatically switching to a suitable circuit module matched with an inputted power system. <P>SOLUTION: The image forming apparatus provided with a power supply device required to be switched to a first voltage specification circuit module or a second voltage specification circuit module and a fixing device for heating and fixing toner to a recording medium by an electric heating means after transferring a toner image formed on an image carrier to the recording medium by using electrophotographic process technology is further provided with: a current detection means 9 for detecting a current allowed to flow into the electric heating means 109c; a circuit module switching means 3 for switching the circuit module to the first voltage specification or the second voltage specification; a comparing means for comparing an output from the current detection means 9 with a reference value of a prescribed level; and a control means 126 for controlling the switching of the circuit module switching means in accordance with an output result of the comparing means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that can support commercial AC power supplies in various countries.

2. Description of the Related Art Conventionally, in image forming apparatuses such as printers and copiers, in order to support the power system of each country, for example, a 100V region and a commercial AC power source in the 200V region, separate power supplies corresponding to the 100V region and the 200V region respectively. Manufacture and use devices and individual fixing devices. For this reason, two types of image forming apparatuses, 100V specification and 200V specification, must be manufactured.
Therefore, there is a problem that costs are incurred in product distribution and inventory management.

  In order to solve this problem, an image forming apparatus that can be used in both a 100 V system region and a 200 V system region is provided using a power supply device and a fixing device that are compatible with both 100 V and 200 V power systems. (Hereinafter referred to as a universal image forming apparatus).

The power supply apparatus in this universal image forming apparatus may require switching of 100V / 200V specification circuit modules according to the input power system in order to support commercial AC power supplies in various countries. In this case, the user manually switches the circuit module of the power supply device to an appropriate mode suitable for the power system in the area to be used (see the conventional example and Patent Document 1).
JP-A-10-105254

  However, in the above-described conventional example, since the user needs to manually switch the specification mode, there is a possibility that an incorrect specification mode is selected. For example, when the user mistakenly switches the specification mode and 200 V input is made to the device switched to the 100 V specification mode, there is a problem that the power supply device and the fixing device break down. On the other hand, when a 100V input is made to the apparatus switched to the 200V specification mode, there is a problem that a fixing temperature sufficient to fix the toner image on the recording paper cannot be secured, resulting in a fixing failure.

  An object of the present invention is to provide an image forming apparatus capable of automatically switching to an appropriate circuit module corresponding to an input power system under the circumstances. To do.

  In order to solve the above problems, in the present invention, the image forming apparatus is configured as described in the following (1), (2), and (3).

(1) The first voltage specification and the second voltage specification circuit module (where the second voltage> the first voltage) need to be switched, and formed on the image carrier using electrophotographic process technology In an image forming apparatus provided with a fixing device that transfers a toner image onto a recording medium and then heat-fixes the toner on the recording medium by an electric heating unit.
Current detecting means for detecting current flowing in the electric heating means;
Said first voltage specification, second voltage specification circuit module switching means;
Comparison means for comparing the magnitude relationship between the output of the current detection means and a reference value of a predetermined level;
Control means for controlling to switch the circuit module switching means according to the output result of the comparison means;
An image forming apparatus.

(2) The first voltage specification and the second voltage specification circuit module (where the second voltage> the first voltage) need to be switched, and formed on the image carrier using the electrophotographic process technology. In an image forming apparatus provided with a fixing device that transfers a toner image onto a recording medium and then heat-fixes the toner on the recording medium by an electric heating unit.
An exothermic temperature detecting means for detecting an exothermic temperature in the electric heating means;
Said first voltage specification, second voltage specification circuit module switching means;
Comparison means for comparing the magnitude relationship between the output of the heat generation temperature detection means and a reference value of a predetermined level;
Control means for controlling to switch the circuit module switching means according to the output result of the comparison means;
An image forming apparatus.

(3) The first voltage specification and the second voltage specification circuit module (where the second voltage> the first voltage) need to be switched, and formed on the image carrier using the electrophotographic process technology. In an image forming apparatus provided with a fixing device that transfers a toner image onto a recording medium and then heat-fixes the toner on the recording medium by an electric heating unit.
Current detecting means for detecting current flowing in the electric heating means;
An exothermic temperature detecting means for detecting an exothermic temperature in the electric heating means;
Said first voltage specification, second voltage specification circuit module switching means;
A comparison means for comparing the output of the current detection means and the output of the heat generation temperature detection means with a reference value of each predetermined level;
Control means for controlling to switch the circuit module switching means according to the output result of the comparison means;
An image forming apparatus.

  According to the present invention, it is possible to automatically switch to an appropriate circuit module corresponding to the input power system, and to improve the reliability of switching selection.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to an embodiment of an image forming apparatus.

An “image forming apparatus” that is Embodiment 1 will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram showing an image forming apparatus using the electrophotographic process of this embodiment, and shows a configuration example of a laser beam printer. The laser beam printer shown in FIG. 1 has a laser beam printer main body (hereinafter referred to as a main body) 101 that can be connected to an external device 131. In addition, a cassette 102 for storing a recording paper 118 as a transfer material is provided at the lower stage of the main body 101.

  Inside the main body 101, there is a recording paper presence sensor 103 that detects the presence or absence of the recording paper 118 in the cassette 102, a cassette size sensor 104 that detects the size of the recording paper 118 in the cassette 102, and a feed that feeds the recording paper 118 from the cassette 102. A paper roller 105 and the like are provided. A registration roller pair 106 that synchronously conveys the recording paper 118 is provided downstream of the paper feed roller 105. Further, an image forming unit 108 that forms a toner image on the recording paper 118 based on the laser beam from the laser scanner unit 107 is provided downstream of the registration roller pair 106. Further, a fixing device 109 that heats and fixes a toner image formed on the recording paper 118 is provided downstream of the image forming unit 108. Downstream of the fixing device 109, a paper discharge sensor 110 that detects the conveyance state of the paper discharge unit, a paper discharge roller 111 that discharges the recording paper 118, and a stacking tray 112 on which the recorded recording paper 118 is stacked are provided. Yes.

  The laser scanner unit 107 includes a laser unit 113 that emits a laser beam modulated based on an image signal transmitted from the external device 131. Further, it is constituted by a polygon motor 114, an imaging lens 115, a folding mirror 116, and the like for scanning laser light from the laser unit 113 on a photosensitive drum 117 described later.

  The image forming unit 108 includes a photosensitive drum 117, a primary charging roller 119, a developing device 120, a transfer charging roller 121, a cleaner 122, and the like necessary for a known electrophotographic process. The fixing device 109 includes a fixing film 109a, a pressure roller 109b, a ceramic heater 109c provided inside the fixing film, and a temperature detection element 109d such as a thermistor for detecting the surface temperature of the ceramic heater.

  The main motor 123 applies a driving force to the paper feed roller 105 via a paper feed roller clutch 124 and to the registration roller pair 106 via a registration roller clutch 125. Further, a driving force is applied to each unit of the image forming unit 108 including the photosensitive drum 117, the fixing device 109, and the paper discharge roller 111.

  The main body 101 has an engine controller 126 and a video controller 127 as control devices. The engine controller 126 and the video controller 127 are connected to each other by an interface 128.

  The engine controller 126 performs control of each electrophotographic process in the laser scanner unit 107, the image forming unit 108, and the fixing device 109, conveyance control of the recording paper 118 in the main body 101, and the like.

  The video controller 127 is connected to an external device 131 such as a personal computer via a general-purpose interface 130. Then, the image information sent from the general-purpose interface 130 is expanded into bit data, and the bit data is sent to the engine controller 126.

  Next, circuit configurations of the power supply device and the fixing device in the laser beam printer will be described.

  FIG. 2 is a block diagram showing circuit configurations of the power supply device and the fixing device in the laser beam printer. A ceramic heater 109 c is connected to the AC power source 1 that supplies power to the entire printer via a fixing device control circuit 7. The fixing device control circuit 7 is composed of a switching element such as a triac or MOSFET, and power supply to the ceramic heater 109c is carried out by on / off control of the switching element. The temperature detection element 109d is a temperature detection element for detecting the temperature of the ceramic heater 109c, for example, a thermistor temperature sensing element. The temperature detected by the thermistor 109d is detected by the resistor 8 and the thermistor 109d as a partial pressure of a control voltage V1 described later, and is A / D input to the engine controller 126.

  The engine controller 126 calculates the electric power to be supplied to the ceramic heater 109c so that the ceramic heater 109c has a predetermined temperature by comparing with the set temperature of the ceramic heater 109c set inside. Then, a drive signal corresponding to the supplied electric power is sent to a switching element in the fixing device control circuit 7, and the ceramic heater 109c is temperature-controlled.

  A low voltage power source 6 is connected to the AC power source 1 via a diode bridge 2 and capacitors 4 and 5. When the relay 3 located between the diode bridge 2 and the capacitors 4 and 5 is on, the AC voltage from the AC power source 1 is doubled rectified and smoothed and input to the low voltage power source 6. When the relay 3 is off, the AC voltage from the AC power source 1 is full-wave rectified and smoothed and input to the low-voltage power source 6. Therefore, the low voltage power source 6 can be a universal power source by turning on the relay 3 when the AC power source 1 is a 100V system and turning off the relay 3 when the AC power source 1 is a 200V system. The diode bridge 2, the capacitors 4 and 5, and the low-voltage power supply 6 constitute a control voltage generating device that generates control voltages (V1, V2) necessary for controlling each part of the printer.

  Next, FIG. 3 shows an amplitude waveform of the current i flowing through the ceramic heater 109c when energization of the ceramic heater 109c is started. 3A shows a case where power is supplied by a 100V AC power source 1, and FIG. 3B shows a case where power is supplied by a 200V AC power source 1. FIG. As shown in FIG. 3, when energized by the 100V AC power supply 1 and when energized by the 200V AC power supply 1, the amplitude of the current i flowing through the ceramic heater 109c at the time of energization becomes 100V system due to the difference in voltage. In comparison, the 200V system is larger.

  Therefore, in the present embodiment, using this, it is attempted to flow the current i through the ceramic heater 109c on a trial basis for a certain period of time until the printer enters a standby state after the printer is turned on. Here, the time for flowing the current i to the ceramic heater 109c is set to a time necessary for flowing a half cycle of the alternating current in order to obtain a peak voltage value of the voltage v described later. A current i detected by a current transformer 9 which is a current detecting device is detected as a voltage v by a voltage conversion circuit including resistors 10 and 11 and diodes 13 and 14. The peak voltage value of the voltage v is detected as shown in FIG. 4 by a peak hold circuit including an operational amplifier 15, a resistor 12, a diode 16, and a capacitor 17. Then, A / D is input to the engine controller 126.

  The engine controller 126 compares the input peak voltage signal with a reference voltage of a predetermined level set inside. If the input peak voltage signal is smaller than the reference voltage, the engine controller 126 determines that the AC power supply 1 is 100V system. . If it is larger, it is determined that the 200V AC power supply 1 is input. The engine controller 126 outputs a High signal when the 100V system is determined and a Low signal when the 200V system is determined to the relay drive circuit including the resistor 18, the transistor 19, and the diode 20.

  When a high signal is output from the engine controller 126, the transistor 19 is turned on, so that the relay 3 is turned on by the control voltage V <b> 2, and the AC power supply 1 is double-voltage rectified and input to the low-voltage power supply 6. That is, the mode is switched to the 100V specification mode. On the other hand, when a low signal is output from the engine controller 126, the transistor 19 is turned off, so that the relay 3 is turned off, and the AC power supply 1 is full-wave rectified and input to the low-voltage power supply 6. That is, the mode is switched to the 200V specification mode. Here, the circuit module is selected in the 200 V specification mode from the time of power-on until the series of control sequences such as current detection, voltage conversion, peak hold, comparison determination, and switching are completed. That is, by turning off the relay 3, it is possible to prevent a situation in which a 200V system input is made to the circuit module switched to the 100V specification mode. Here, when a 100 V system input is made to the circuit module switched to the 200 V specification mode, the maximum power of the low-voltage power supply 6 cannot be output, but the power for driving the engine controller 126 and the control voltages V1, V2 This control sequence can be realized.

  As described above, according to this embodiment, it is possible to automatically switch to an appropriate circuit module regardless of whether the power system of the AC power supply 1 is a 100 V system or a 200 V system, and the switching selection is performed. Can improve the reliability.

  An “image forming apparatus” that is Embodiment 2 will be described with reference to FIGS. In addition, in the following description, description is abbreviate | omitted about the point which overlaps with Example 1. FIG.

  In this embodiment, instead of the peak hold circuit in the first embodiment, an integration circuit constituted by an operational amplifier 15, resistors 12, 21 and capacitors 17, 22 and a discharge switch 23 as shown in FIG. The configuration applied in the previous stage is adopted. As a result, the switching sequence of the 100V / 200V specification circuit module is performed as in the first embodiment.

  The difference from the first embodiment is that the integration value v ′ of the voltage v is detected as shown in FIG. 6 by the integration circuit, and the integration value signal is A / D input to the engine controller 126. The engine controller 126 compares the input integral value signal with a reference voltage of a predetermined level set internally, and if the input integral value signal is smaller than the reference voltage, it is a 100V AC power supply 1, and if larger, it is 200V. It is a point to determine that the AC power supply 1 of the system is input. Note that after a current corresponding to a half cycle of the alternating current flows, the engine controller 126 outputs a signal for turning on the discharge switch 23 to reset the integral value v ′.

  In this embodiment, since the voltage value is integrated and output by the integration circuit, the influence of disturbance noise can be reduced as compared with the first embodiment.

  As described above, according to the present embodiment, it is possible to automatically switch to an appropriate circuit module regardless of whether the power system of the AC power supply 1 is a 100V system or a 200V system. Further, by using an integration circuit in the current value detection sequence, the reliability of the switching selection can be further enhanced.

  An “image forming apparatus” that is Embodiment 3 will be described with reference to FIGS. In addition, in the following description, description is abbreviate | omitted about the point which overlaps with Example 1 and Example 2. FIG.

  In this embodiment, the switching sequence of the 100V / 200V specification circuit module is the same as that in the first embodiment, and a signal to be A / D input to the engine controller 126 is generated by a temperature detection element such as a thermistor 109d as shown in FIG. It is detected and generated as a temperature rise.

  As in the case described in the first embodiment, FIG. 8 shows how the heat generation temperature T rises in the ceramic heater 109c when the energization of the ceramic heater 109c is started. 8A shows a case where power is supplied by a 100V AC power source 1, and FIG. 8B shows a case where power is supplied by a 200V AC power source 1. FIG.

  As shown in FIG. 8, when energized by a 100V AC power source 1 and when energized by a 200V AC power source 1, the degree of heat generation temperature rise in the ceramic heater 109c during energization is 100% compared to 100V due to the difference in power. 200V is larger.

  Therefore, in this embodiment, using this, it is attempted to energize the ceramic heater 109c experimentally for a certain period of time until the printer enters a standby state after the printer is turned on.

  The temperature detected by the thermistor 109d, which is a temperature detection device, is detected as a partial pressure of the control voltage V1 by the resistor 8 and the thermistor 109d, and the degree of increase in heat generation temperature before and after the energization of the ceramic heater 109c is detected by the engine controller 126. D is input. The engine controller 126 compares the input heat generation temperature information with a reference value of a predetermined level set internally, and if the input heat generation temperature rise is smaller than the reference value, it is 100V AC power supply 1; It is determined that the 200V AC power supply 1 is input. As described above, in this embodiment, the current detection device, the voltage conversion circuit, and the like provided in the first and second embodiments can be not mounted. Note that the power supply system may be determined based on the length of time until the predetermined temperature is reached.

  As described above, according to this embodiment, it is possible to automatically switch to an appropriate circuit module regardless of whether the power system of the AC power supply 1 is a 100 V system or a 200 V system, and the switching selection is performed. Can improve the reliability.

  An “image forming apparatus” that is Embodiment 4 will be described with reference to FIGS. 5 and 9. In addition, in the following description, description is abbreviate | omitted about the point which overlaps with Example 1- Example 3. FIG.

  In this embodiment, as shown in FIG. 5, the switching sequence of the 100V / 200V specification circuit module similar to that in the second embodiment is performed together with the detection of the heat generation temperature of the ceramic heater 109c by the thermistor 109d.

  A control flow in this embodiment is shown in FIG. The processing of the illustrated flow is performed by the CPU in the engine controller 126 in FIG.

  In this embodiment, as shown in FIG. 9, after the printer is turned on, until the printer enters a standby state, a current i is experimentally applied to the ceramic heater 109c until the ceramic heater 109c reaches a predetermined target temperature. Attempt to flow (S3). Meanwhile, a sequence of current detection (S4), voltage conversion (S5), integration (S6) is performed, and the integration value signal is A / D input to the engine controller 126 (S7). As soon as the ceramic heater 109c reaches the target temperature, the energization is cut off (S8).

  After the energization is completed, the engine controller 126 compares the average value of the input integral value signal with a reference voltage of a predetermined level set inside, and if the average value of the input integral value signal is smaller than the reference voltage. For example, it is determined that the 100V AC power source 1 is input, and if it is larger, the 200V AC power source 1 is input (S9, S10).

  When it is determined that the input voltage is 100V, the relay 3 is turned on (S11). When it is determined that the input voltage is not 100V, the relay 3 is turned off.

  In the switching sequence of the 100V / 200V specification circuit module in the first and second embodiments, the time for supplying the current i to the ceramic heater 109c is limited to the time required for supplying a half cycle of the alternating current. However, in this embodiment, by monitoring the heat generation temperature of the ceramic heater 109c by the thermistor 109d, the ceramic heater 109c can be energized until a certain target temperature is reached. For this reason, it becomes possible to take a plurality of samples of the current detection signal, and the accuracy of the current value detection sequence can be further improved.

  As described above, according to the present embodiment, it is possible to automatically switch to an appropriate circuit module regardless of whether the power system of the AC power supply 1 is a 100V system or a 200V system. In the switching sequence of the 100V / 200V specification circuit module, the reliability of the switching selection can be further enhanced by using both current detection and heat generation temperature detection.

1 is a configuration diagram of an image forming apparatus according to a first embodiment. Block diagram of power supply and fixing device in embodiment 1 The figure which shows the electric current amplitude of the ceramic heater in Example 1. The figure which shows the peak value of the electric current amplitude of the ceramic heater in Example 1. Block diagrams of a power supply device and a fixing device in the second and fourth embodiments The figure which shows the integrated value of the electric current amplitude of the ceramic heater in Example 2. Block diagram of a power supply device and a fixing device in Embodiment 3 The figure which shows the heat_generation | fever temperature rise of the ceramic heater in Example 3 The figure which shows the control flow in Example 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Diode bridge 3 Relay 4, 5 Capacitor 7 Fixing device control circuit 9 Current transformer 126 Engine controller

Claims (8)

A power supply device that requires switching between a first voltage specification and a second voltage specification circuit module (where second voltage> first voltage), and a toner image formed on an image carrier using electrophotographic process technology In an image forming apparatus provided with a fixing device that heat-fixes the toner on the recording medium by an electric heating means after being transferred onto the recording medium.
Current detecting means for detecting current flowing in the electric heating means;
Said first voltage specification, second voltage specification circuit module switching means;
Comparison means for comparing the magnitude relationship between the output of the current detection means and a reference value of a predetermined level;
Control means for controlling to switch the circuit module switching means according to the output result of the comparison means;
An image forming apparatus comprising: The image forming apparatus according to claim 1.
An image forming apparatus comprising: an energizing unit configured to energize the electric heating unit for a certain period of time; the energizing unit energized the electric heating unit for a certain period of time; and the current detecting unit detects a current flowing through the electric heating unit. apparatus. A power supply device that requires switching between a first voltage specification and a second voltage specification circuit module (where second voltage> first voltage), and a toner image formed on an image carrier using electrophotographic process technology In an image forming apparatus provided with a fixing device that heat-fixes the toner on the recording medium by an electric heating means after being transferred onto the recording medium.
An exothermic temperature detecting means for detecting an exothermic temperature in the electric heating means;
Said first voltage specification, second voltage specification circuit module switching means;
Comparison means for comparing the magnitude relationship between the output of the heat generation temperature detection means and a reference value of a predetermined level;
Control means for controlling to switch the circuit module switching means according to the output result of the comparison means;
An image forming apparatus comprising: The image forming apparatus according to claim 3.
An image is provided with energizing means for energizing the electric heating means for a certain period of time, the energizing means energizes the electric heating means for a certain period of time, and the exothermic temperature detecting means detects the heat generation temperature in the electric heating means. Forming equipment. A power supply device that requires switching between a first voltage specification and a second voltage specification circuit module (where second voltage> first voltage), and a toner image formed on an image carrier using electrophotographic process technology In an image forming apparatus provided with a fixing device that heat-fixes the toner on the recording medium by an electric heating means after being transferred onto the recording medium.
Current detecting means for detecting current flowing in the electric heating means;
An exothermic temperature detecting means for detecting an exothermic temperature in the electric heating means;
Said first voltage specification, second voltage specification circuit module switching means;
A comparison means for comparing the output of the current detection means and the output of the heat generation temperature detection means with a reference value of each predetermined level;
Control means for controlling to switch the circuit module switching means according to the output result of the comparison means;
An image forming apparatus comprising: The image forming apparatus according to claim 5.
The comparison unit compares the output of the current detection unit with the reference value until the output of the heat generation temperature detection unit reaches the reference value. The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the control means switches to the second voltage specification circuit module until the circuit module switching means is switched according to the output result of the comparison means. The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the first voltage specification is a 100V system specification, and the second voltage specification is a 200V system specification.

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