JP2007110355A - Data communication equipment and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide data communication equipment along with an image forming apparatus, capable of optimizing a used carrier frequency for improved communication stability and suppressed radiation noises, and also capable of significantly reducing connection bundle in electronic devices. <P>SOLUTION: The communication equipment in an electronic device communicates with load modules by superposing carrier waves on the power line. It comprises a means for detecting transmission path characteristics between modules by transmitting/receiving the sine wave signal set with specified frequency range and amplitude, using a communication means provided to a main control module and the load modules. The frequency of communication carriers is selected for each module, based on the detection result of the transmission path detection means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a data communication apparatus and an image forming apparatus that transmit a plurality of data by serial communication using a power supply line as a communication medium.

  Currently, in various devices, data is exchanged between devices existing inside the device, and the amount of data to be handled tends to increase as the size of the device increases. When data is exchanged on the same board, data can be exchanged in a normal bus format.

  However, when data in a bus format is exchanged between different substrates using bundles or the like, an enormous number of bundles is required. On the other hand, serial communication in which data is arranged and transmitted in time series using one or a few signal lines is well known as a method for reducing the number of bundles.

  There are various types of serial communication, such as clock synchronous communication that performs communication while adding a serial transfer clock, and asynchronous communication that does not add a clock.

  The asynchronous communication method without adding a clock has a great advantage that the number of bundles can be reduced. On the other hand, the clock synchronous communication does not require a circuit such as a synchronization circuit on the receiving side, so that the circuit configuration is simple and has an advantage that it can be constructed at a low cost as a whole.

Stepping motor drive control that can be controlled by receiving various sensor data at regular intervals and sending command value data as a main application utilizing the features of serial communication means in devices such as copiers and printers And is used to reduce the circuit scale (see, for example, Patent Document 1 and Non-Patent Document 1).
JP 2003-224552 A "Transistor technology SPECIAL No.51" CQ publication

  As described above, the data transmission / reception means can reduce the number of bundled wires by serial communication. However, in addition to data communication, each power supply line corresponding to each load is connected to each board constituting the electronic circuit. Is indispensable and the number of wire numbers is small due to the difference in the amount of current required compared to the signal line (thick wire diameter), and as a result, there is no significant difference in the volume of the bundled wire. The ratio of the internal ratio has not changed significantly. In particular, when a plurality of motors need to be arranged and controlled inside a device such as a copying machine, the number of bundled wires required and the volume of the wires obstruct the downsizing of the device, and the power line As a result, inductive noise is generated by connecting the signal line and the signal line, resulting in sensor malfunction and the like.

  In such a situation, it is further necessary to reduce the bundling by serial communication as multiple drive sources and multiple sensor signals for control are required due to the necessity of complicated control accompanying the enhancement of equipment functions. On the other hand, a large improvement in the volume ratio of the in-device bundles is becoming impossible due to the increase in the number of power supplies and detection bundles exceeding that.

  Also, the speed required for communication between modules is increasing as the speed of the apparatus increases. For example, conventional serial communication on a PC, which was relatively low-speed communication from 9600 bps to 56 kbps at the fastest, as in the RS232C standard, has now adopted the universal serial bus (commonly known as USB) standard for serial transmission. .1 standard has been adopted as being capable of supporting up to 4 M to 10 Mbps, and higher speed 2.0 standard up to 480 Mbps.

  In this way, with the increase in functionality and speed of equipment, the number of load module groups constituting the equipment and the increase in communication speed between modules are indispensable.

  However, the increase in communication speed is a major factor that increases the generation of radiation noise. Conventionally, noise countermeasures for communication lines have not been required much, but the cost required for noise countermeasures and the volume ratio due to increased members The problem of an increase has been occurring.

  The present invention has been made in view of the above problems, and the intended process is to optimize the carrier frequency to be used, improve the stability of communication, and suppress radiation noise. An object of the present invention is to provide a data communication apparatus and an image forming apparatus that can reduce connection bundles in an electronic apparatus device.

  As one means for solving such an increase in the number of bundled wires, power line communication in which inter-module communication is already performed using a power supply line is known. As a conventional power line communication technique, a communication system using a plurality of carriers used for wireless communication for the purpose of improving communication efficiency and improving reliability has been proposed. In particular, as a countermeasure against the occurrence of a communication error due to a change in the signal attenuation rate for each carrier frequency when using a plurality of carrier waves, there is also a proposal such as correcting and outputting a signal that is attenuated between communication devices in advance. Has been done.

  However, in the case of correcting the attenuation as described above, the receiving side needs a measuring means such as what value the communication data has with respect to a predetermined value. Had a problem that made it unsuitable.

  In view of these points, the present invention proposes a method that can implement a measurement function only in a module on the main control side so that it can be installed in a copying machine or the like, and can realize the reception side with a simple configuration, In addition, the following configuration is provided for the purpose of proposing a method capable of suppressing radiation noise generated from a power supply line used for communication without providing physical means by increasing communication speed. .

1. In an electronic device communication device that communicates with each load module by superimposing a carrier wave on a power line,
Means for detecting transmission path characteristics between the modules by transmitting and receiving a sine wave signal set with a specified frequency range and amplitude by means of communication provided in the main control module and each load module. And a frequency of a communication carrier wave is selected for each of the modules based on a detection result of the transmission path detecting means.

  2.1. The transmission line characteristic detection means transmits a sine wave signal of a predetermined frequency range and amplitude to a specific module at an arbitrary timing between the main control module and each load module or between each load module. And a means for measuring a change delay time of a standing wave generated by the reflected wave, and calculating a transmission line characteristic.

  3.1. The transmission line characteristic detection means transmits a sine wave signal having a predetermined frequency range and amplitude to a specific module at any timing between the main control module and each load module or between each load module. The transmission impedance of the power supply line is calculated by means of measuring the amplitude ratio of the standing wave generated by the reflected wave and the phase difference for each frequency, and the length of the power supply line is detected from the result. It is characterized by doing.

  4.1. The transmission line characteristic length detection means includes an input impedance switching means for each load module, a current detection means on the main control module side, and a means for measuring a voltage and current phase difference for each frequency to be transmitted. Thus, the transmission impedance of the power supply line is calculated, and the length of the power supply line is detected from the result.

5. In an image forming apparatus that communicates with each load module by superimposing a carrier wave on a power line,
It is configured to transmit a sine wave signal set to an arbitrary frequency set with a reference amplitude by the communication means, and is generated by the transmitted sine wave signal and a reflected wave with respect to the transmitted sine wave signal in the communication line between the load modules. By providing means to detect amplitude fluctuations due to standing waves and changing the communication carrier frequency so that the amplitude ratio is below the specified value, the noise emission from the power supply line will be reduced and communication will be reduced. It is characterized by improving the error correction frequency due to waveform distortion of data.

  6.5. The communication means provided in each module includes an input impedance switching means, so that the short-circuit / opening of the input stage can be set at a predetermined timing when detecting the amplitude of the standing wave by the reflected wave. And

  With the configuration as described above, line characteristics can be measured from standing waves generated in the power supply line, and the communication carrier frequency setting in the line does not become 1/4 or 1/2 of the wavelength of the carrier wave at which noise radiation increases. This makes it possible to eliminate the need for physical noise countermeasures, and it is also possible to set the frequency so that waveform distortion does not occur due to line characteristics, resulting in communication data errors. It is characterized by providing power line communication capable of suppressing the frequency and improving the communication efficiency.

  According to the present invention, when performing power line communication, the carrier frequency to be used can be optimized by obtaining the transmission line characteristics and line length from the reflected wave of the carrier wave, and waveform distortion due to the line impedance can be reduced. It is possible to improve the stability of communication by considering it, and by setting the carrier frequency from the transmission line length, it is possible to set the carrier frequency that makes the transmission line difficult to become an antenna, so it is possible to suppress radiation noise, In addition, it is possible to greatly reduce the number of connection wires in the electronic device.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  The configuration diagram of the embodiment shown in FIG. 1 shows the configuration of a communication system incorporated in an image forming apparatus 100 represented by a copying machine or a printer. The power line communication system includes a transmitting device 101 that transmits data and a receiving device 201 that receives data.

  Here, a main body configuration of a conventional digital multifunction peripheral is shown in FIG. 10, and the above problem will be described in detail by taking a digital copying machine as an image forming apparatus as an example. The document conveying unit 130 is configured as follows.

  That is, the documents set on the document table 131 are conveyed one by one to the document reading position by the paper feed roller 132. The original reading position is set at a predetermined position by the original conveying belt 137 driven by the motor 136, and the original reading operation is performed by the original reading unit 120. After the document reading operation, the conveyance path is changed by the flapper 135, and the document is discharged to the discharge tray 138 by rotating the motor 136 in the reverse direction.

  The document reading unit 120 is configured as follows.

  That is, the exposure lamp 122 is composed of a fluorescent lamp, a halogen lamp, and the like, and irradiates the document on the document placement glass (document table) 126 while moving in the direction perpendicular to the longitudinal direction. Scattered light from the document due to irradiation of the exposure lamp 122 is reflected by the first, second, and mirror tables 121 and 123 and reaches the lens 124. At this time, the second mirror stage 123 moves at a half speed relative to the movement of the first mirror stage 121, and the distance from the irradiated original surface to the lens 124 is always kept constant.

  The first mirror stage 121 and the second mirror stage 123 are moved by a reading motor 125. An image on the original is formed on a light receiving portion of a CCD line sensor 127 in which thousands of light receiving elements are arranged in a line via mirror stands 121 and 123 and a lens 124, and the CCD line sensor 127 sequentially forms a line. It is photoelectrically converted in units. The photoelectrically converted signal is processed by a signal processing unit (not shown), PWM-modulated and output.

  The image forming unit 100 is configured as follows.

  That is, the exposure control unit drives the semiconductor laser 50 based on the PWM-modulated image signal that is the output of the signal processing unit, and irradiates the surface of the photoconductor 52 rotating at a constant speed. At this time, the light beam is deflected and scanned using the polygon mirror 51 rotated by the motor 54 in parallel with the axial direction of the drum-shaped photoconductor 52. Note that the remaining charge on the drum is removed from the photosensitive member 52 by a pre-exposure lamp (not shown) before the light beam is irradiated, and the surface of the primary charger (not shown) is uniformly charged. Accordingly, the photosensitive member 52 receives the light beam while rotating, thereby forming an electrostatic latent image on the drum surface. The developing unit 53 visualizes the electrostatic latent image on the drum surface with a developer (toner) of a predetermined color.

  Transfer paper transported from transfer paper feed stages 140, 150, 160, 170, 180 described later is transported to the registration roller 55. The registration roller 55 detects the arrival of the transfer paper using the sensor 56, and feeds the transfer paper to the transfer position in accordance with the timing of the leading edge of the image formed on the photoconductor 52 and the leading edge of the transfer paper.

  Further, in order to detect the transfer timing of the transfer paper in addition to the sensor 56 in the paper feed path, a sensor (not shown) is also arranged at each transfer paper feed stage exit or the like, and the stop position when it is not normally conveyed. It is also used to grasp the relationship.

  A transfer charger 57 transfers the developed toner image on the photosensitive member 52 onto the fed transfer paper. After the transfer, the remaining toner is removed from the photoconductor 52 by a cleaner (not shown). The transfer paper after the transfer is easily separated from the photoconductor 52 because the curvature of the photoconductor 52 is large. Further, by applying a voltage to a static elimination needle (not shown), the adsorption between the photoconductor 52 and the transfer paper is performed. We weaken power and make separation easy.

  The separated transfer paper is sent to the fixing unit 58 to fix the toner. Reference numeral 110 denotes a ceramic heater and film 111 and two rollers, and the heat of the ceramic heater 110 is efficiently transferred through the thin film 111. The cooling roller radiates heat from the fixing unit roller. The feeding roller is composed of one large roller and two small rollers, and feeds the transfer paper from the fixing unit and corrects the curl of the transfer paper.

  The direction flapper 112 switches the discharge destination of the transfer paper to the tray 114 and the transport unit 190 according to the operation mode.

  The transport unit 190 is configured as follows.

  That is, the transfer paper is transported by the transport roller 191 in a unit for transporting the transfer paper to the post-processing apparatus 10 described later. Reference numerals 140, 150, 160, and 170 denote main body sheet feed stages, which are configured by the same mechanism. 180 is a deck paper feed stage that can store a larger amount of transfer paper than 140, 150, 160, and 170. Since the main body paper feed stages 140, 150, 160, and 170 have almost the same configuration, the configuration will be described using the main body paper feed stage 140 as an example.

  A bottom plate 142 that is moved up and down by a lift-up motor 143 is disposed on the bottom surface of the cassette 141 that stores and stores transfer paper. When the bottom plate 142 is raised, the transfer paper can be waited at a predetermined standby height. The transfer paper waiting at a predetermined position is conveyed to the paper feed roller pair 145 using the pickup roller 144. The feed roller pair 145 is applied with a torque in the reverse rotation direction to the paper feed, thereby feeding the transfer sheets one by one to the transport path while preventing double feeding of the recording medium. The transport roller pair 146 is a pair of rollers for transporting the transfer paper transported from the paper feed stage below the main body paper feed stage 140 further upward. The paper feed motor 147 is a motor for driving the paper feed roller pair 145 and the transport roller pair 146.

  The deck paper feed stage 180 is configured as follows.

  That is, the bottom plate 182 for raising the transfer paper to the standby position is also arranged on the bottom surface of the paper storage 181 for storing and storing the transfer paper. The bottom plate 182 is connected to a belt that is rotated by a motor 183, and the raising and lowering of the bottom plate 182 is controlled by the movement of the belt. The transfer paper in the standby position is conveyed to the paper feed roller pair 184 by the pick-up roller 185, and the transfer paper is conveyed to the conveyance path while preventing multi-feeding as in the case of the main body paper feed. The paper feed motor 187 is a motor for driving the paper feed roller pair 184.

  The post-processing device 10 is configured as follows.

  That is, the transfer paper from the image forming unit 100 is received by the roller 32 into the post-processing apparatus 10. When the tray 14 is selected as the output destination of the received transfer paper, the transport direction is switched by the flapper 33 and the transfer paper is discharged to the tray 14 using the roller 34. The tray 14 is a discharge tray that is used temporarily for a discharge destination or the like of processing that is interrupted during normal processing.

  The trays for normal discharge are the tray 18 and the tray 19. These trays can be discharged by switching the conveyance path downward by the flapper 33 and further selecting the conveyance path toward the roller 16 by the flapper 30. When the conveyance path is selected vertically downward by the flappers 30 and 31, and the conveyance direction is reversed by the reversing roller 15, reverse paper discharge is possible. When the trays 18 and 19 are discharged, stapling using the stapler 17 is possible. Whether the transfer paper is output to the tray 18 or the tray 19 is determined by moving the tray itself up and down using the shift motor 20. Also in this case, a plurality of sensors (not shown) are provided in the conveyance path during the paper discharge process, and the reversal process timing is detected and used to control the drive timing of the flapper and the reversal roller.

  The tray 27 is a discharge tray used during bookbinding. The transfer paper is conveyed from the roller 15 to the roller 21 and a predetermined amount of transfer paper is stored in the primary storage unit 23. After the accumulation is completed, the bookbinding operation is performed by the stapler 24, the direction of the flapper 25 is changed, the roller 22 is rotated in the direction opposite to that during accumulation, and the sheet is discharged to the tray 27 via the roller 26.

  When the image forming unit 100, the document reading unit 120, the main body paper feed stage 140, and the deck paper feed stage 180 are separable, a connection method by serial communication is generally used in consideration of simplification of the interface. It is. In this case, each motor, for example, the reading motor 125 and the paper feeding motor 147 is controlled by serial communication from a control device (not shown) inside the image forming unit 100.

  Next, the communication device will be described.

  The transmission apparatus 101 supplies power to each load module from an interface 111 for transmitting / receiving command data for each load module from the controller 110 of the image forming apparatus, modulation / demodulation means 112 for data to be transmitted / received, and a DC power source. It comprises a coupling means 113 for superimposing (separating) modulation (demodulation) data on the DC power line. The interface 111 is connected to the controller in a bus format, and has a function of converting received parallel data serially and converting data to be transmitted from serial data to parallel data.

  Similarly to the transmission apparatus 101, the reception apparatus 201 separates data transmitted from the transmission apparatus 101 from the DC power supply line, and demodulates the received data, and a coupling unit 211 that superimposes data to be transmitted to the transmission apparatus 101. Further, the motor driving circuit includes a duplex / modulation unit 212 for modulating data to be transmitted and a serial-parallel conversion unit 213 that converts the modulated serial data into parallel data as various control data to the driving circuit. It is used to change the drive current value to, and to change the full-step / half-step drive mode.

  In contrast to the above procedure, the result of detecting the state of the drive circuit is converted from parallel data to serial data, modulated, and superimposed as communication data on the power supply line.

  The receiving device 201 is provided with an impedance switching unit 251 that also serves as a low-pass filter, and a predetermined DC power source from the DC power source 1002 is supplied to the load control unit 221 through the power supply line and It is used after being converted into a voltage required by the receiving device 201 and the load control means 221 by the illustrated DC-DC converter or the like. As means for modulating the data signal in order to superimpose the communication data signal on the power line, amplitude modulation (AM: Amplitude Modulation, ASK: Amplitude Shift Keying in digital modulation) as shown in FIG. 2 and as shown in FIG. A method such as frequency modulation (FM: Frequency Modulation, or FSK: Frequency Shift Keying in digital modulation) can be set.

  Here, a transmission characteristic detection method will be described.

  The controller 1000 of the main control module 101 superimposes the carrier wave on the power supply line as a sine wave set as a predetermined amplitude value. At this time, the frequency of the carrier wave is swept at a predetermined increase d [Hz] at any two or more values (for example, 10 k to 1 MHz) and transmitted for a predetermined time. The modulation / demodulation means 112 has a function of demodulating the received data, and has a configuration for reading the frequency and amplitude of the signal superimposed on the power supply line by this demodulation function. Thus, the reflected wave from each load module of the predetermined sine wave signal transmitted within the predetermined time is received, and the amplitude ratio (FIG. 6: for the transmission sine wave with respect to each frequency setting) is received by the demodulating means. Reflected waves with reflection ratios 0.8 and 0.4) and phase difference (FIG. 7: phase difference of reflected wave due to difference in reception impedance when reflection ratio is 1 with respect to transmission sine wave) are read. .

  Here, the frequency is swept, the amplitude ratio of the standing wave at each frequency is updated, and the maximum frequency and the minimum frequency are recorded. From these two measurement results, the resistance component and the inductor component can be calculated. That is, since the reluctance for the inductor L changes from the frequency f1 that is the minimum impedance and the frequency f2 that is the maximum impedance, and the phase also changes, the impedance of the target line: Z = R + jωL (−j1 / ωC) : Ignored here for simplification).

  The configuration of the impedance switching means 251 provided on the load module side is such that the inductor 252 and the resistor 253 constituting the low-pass filter are switched by the switching means 255 as shown in FIG. Thereby, even when a plurality of load modules are connected, the line impedance of the measurement target module changes as shown in FIG. 5 by sequentially changing the switching for each load module. That is, by grasping the order of the switching operation on the load module side, the corresponding load module can be determined.

  Also, when the frequency is swept, the part where the rate of change of impedance becomes extremely large is regarded as the resonance frequency of the transmission line, and when the carrier wave of that frequency is set, the noise emission from the line is the largest. As a part to be used, it is set as a use prohibited area as a communication carrier wave.

As described above, the carrier frequency is set avoiding the resonance point where the impedance changes extremely. For example, as shown in FIG. 8, two types of carrier waves having different frequencies are used for two types of load modules. By adopting a communication configuration, it is also possible to use a configuration in which the reception timing of communication data is set using the level change of the basic carrier wave (n, p). As an operation on the receiving side in this case, the amplitude modulation shown in FIG. 2 is performed from the second carrier data further superimposed on the basic carrier, with the case where the level of the basic carrier exceeds a predetermined value as a synchronization timing. Demodulated as communication data.

  By setting the carrier frequency to be set for each communication target module according to the line length in this way, it becomes possible to share the synchronization timing and suppress waveform distortion due to the line impedance. It becomes possible.

  Further, when the multicarrier modulation method is adopted as another modulation method, the frequency allocation of communication data bits may be performed based on the calculation of the line length from the measurement results at any two frequencies as described above. Alternatively, the amplitude ratio of the carrier wave in the entire frequency band of the carrier wave to be used is measured, and the standing wave ratio is large where the carrier wave amplitude ratio is large as shown in FIG. Since there is a concern, there is no problem in adopting a configuration in which communication data bits are excluded from the frequency band to be allocated (in FIG. 9, the allocation at frequencies f0 and fn-1 where the reflected wave amplitude ratio is equal to or higher than the predetermined value Aref is excluded). . In this case, the means for calculating the line constant can be reduced, and the configuration on the main control module side can be simplified.

1 is a block diagram illustrating a configuration example of a communication system including a transmission device and a reception device in an image forming apparatus according to a first embodiment of the present invention. Modulation scheme: a schematic diagram of a modulation signal in amplitude modulation (ASM). It is a schematic diagram of data modulation by frequency modulation (FSM). It is a block diagram of a load module side impedance switching means. It is a track constant calculation conceptual diagram. It is an amplitude change figure of the reflected wave according to load module with respect to a transmission sine wave. It is a phase change figure of the reflected wave by the impedance switching means with respect to a transmission sine wave. It is a data modulation schematic diagram according to the module at the time of the frequency modulation by a multicarrier. It is a frequency allocation conceptual diagram at the time of multicarrier modulation (frequency spreading). 1 is a cross-sectional view of a digital copying machine as an image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Post-processing apparatus 100 Image forming apparatus 101 Transmission apparatus 120 Document reading part 130 Document conveyance part 201 Reception apparatus

Claims (6)

In an electronic device communication device that communicates with each load module by superimposing a carrier wave on a power line,
Means for detecting transmission path characteristics between the modules by transmitting and receiving a sine wave signal set with a specified frequency range and amplitude by means of communication provided in the main control module and each load module. A data communication apparatus comprising: selecting a frequency of a communication carrier for each module based on a detection result of the transmission path detection means.   The transmission path characteristic detection means transmits a sine wave signal having a predetermined frequency range and amplitude to a specific module at an arbitrary timing between the main control module and each load module or between each load module. 2. The data communication apparatus according to claim 1, wherein the transmission line characteristic is detected by measuring a change delay time of the reflected wave.   The transmission line characteristic detection means transmits a sine wave signal having a predetermined frequency range and amplitude to a specific module at an arbitrary timing between the main control module and each load module or between each load module. The transmission impedance of the power supply line is calculated by measuring the attenuation factor of the amplitude and the phase difference for each frequency, and the length of the power supply line is detected from the result. Item 4. A data communication device according to Item 1.   The bundle wire length detection means includes input impedance switching means for each load module, current detection means on the main control module side, and means for measuring a phase difference between a voltage and a current for each frequency to be transmitted. The data communication device according to claim 1, wherein the transmission impedance of the power supply line is calculated and the length of the power supply line is detected from the result. In an image forming apparatus that communicates with each load module by superimposing a carrier wave on a power line,
It is configured to transmit a sine wave signal set to an arbitrary frequency set with a reference amplitude by the communication means, and is generated by the transmitted sine wave signal and a reflected wave with respect to the transmitted sine wave signal in the communication line between the load modules. By providing means to detect amplitude fluctuations due to standing waves and changing the communication frequency so that the amplitude ratio is less than the specified value, the noise emission is reduced and errors due to waveform distortion of communication data An image forming apparatus characterized by improving a correction frequency.   6. The communication means provided in each module is provided with an input impedance switching means so that the short-circuit / opening of the input stage can be set at a predetermined timing when the amplitude of the reflected wave is detected. Image forming apparatus.

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