JP2007116625A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can perform motor control while reducing a capacity ratio of bundles within the apparatus and reducing an occupancy ratio of a connector in a substrate of circuits caused by the bundle reduction. <P>SOLUTION: An image forming apparatus comprises: a power line communication transmission device constructed from a modulation circuit for converting data into a predetermined data form with respect to a power feeding line, a carrier frequency setting means for setting a carrier wave to be used for the modulation circuit to an arbitrary frequency, and a transmission coupling means for superimposing a communication signal generated by the modulation circuit onto said power line; a reception coupling means for receiving a signal from the transmission device and extracting the superimposed communication data from the power feeding line; and a means for detecting the frequency of the carrier wave corresponding to the modulation means from the communication signal from the reception coupling means. Furthermore, a control CLK generating means is provided for generating a CLK signal for motor driving control by providing a means for demodulating said communication signal and setting a frequency dividing ratio of the carrier wave in accordance with the data. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that transmits 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 bus-type data 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 exchanged in time series using one or a few signal lines is well known as a method for reducing the number of bundled lines.

  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).

  Here, a conventional serial communication example will be described with reference to FIGS.

  FIG. 13 shows an internal circuit of the conventional transmission apparatus 200. Control of the transmission device 200 is performed by the control CPU 201. A ROM memory 202 and a RAM memory 203 are connected to the CPU as program storage devices. S-CLOCK as a communication clock signal is supplied by CLOCK 207, and some circuits inside transmission apparatus 200 operate in synchronization with the clock from CLOCK 207.

  A parallel / serial conversion circuit 206 exists to generate S-DATA as a serial data signal. Data to the converter is supplied from the CPU via the latch circuit 204. When the CPU decides to start communication, data is loaded into the parallel / serial conversion circuit. In practice, a signal is generated from the CPU port (hereinafter referred to as a transmission start source signal), and load data is generated in the LD * signal via the SYNC circuit 208.

  As shown in FIG. 14, the SYNC circuit 208 is a timing circuit that detects a signal falling edge of the In input unit and generates an “L” signal for one clock synchronized with the input clock signal. S-LATCH * as a reception timing signal is generated by the down counter circuit 209. The start of the down-count is synchronized with the output of the SYNC circuit 208 as in the parallel / serial conversion circuit 206.

  CPU obtained by adding the number of effective bits of the serial communication data set by the latch circuit 204 to the internal delay number (clock delay required until the data latch unit) of the receiving apparatus 102, which will be described later, as a downcount load value Is set through the latch circuit 205. As a result, the reception confirmation timing on the receiving apparatus 400 side in FIG. 9 can be changed, and even when the circuit of the receiving apparatus is changed, it can be easily handled.

  FIG. 15 shows an internal circuit of the receiving apparatus 400.

  In the synchronous communication, the clock is also transferred at the same time, so that no specific clock is required for reception. The receiving device 400 includes a serial / parallel conversion circuit 402 that changes serial data to parallel data, and a latch circuit 403 that latches parallel data. Since S-DATA is transmitted in synchronization with the rising edge of S-CLOCK, the receiving device 400 side inverts the input S-CLOCK by the inversion circuit 401 and uses it as an operation clock in the serial / parallel conversion circuit 402. use. As a result, by receiving at the falling edge of S-CLOCK, the margin for transmission delay by the communication line is increased. The latch circuit 403 determines the parallel data from the serial / parallel conversion circuit 402 at the rising edge of S-LATCH *.

  FIG. 16 shows an example of communication when the transmitting apparatus 200 of FIG. 13 and the receiving apparatus 400 of FIG. 15 are used. Here, the effective bit number of the communication data is 8 bits, the data to be sent is D1 [7: 0], and the data already determined on the receiving device 400 side is D0 [7: 0]. Data D1 is transmitted in order from 0 bit in synchronization with the rising edge of S-CLOCK. Either LSB first or MSB first may be used.

  Only the circuit in the serial / parallel conversion circuit 402 in the receiving apparatus 400 changes. At the same time as the transfer of the eighth bit data D1 [7], S-LATCH * becomes “L” for one clock. In the receiving circuit shown in FIG. 9, since no internal delay occurs, it is simultaneously with D1 [7]. The data is changed from D0 [7: 0] to D1 [7: 0] in synchronization with the rising edge of S-LATCH *.

The data change timing depends on S-LATCH *. The S-LATCH * is output after being shifted from the port output of the CPU 201 by a certain time corresponding to the down count value set by the down counter 209. As a result, if the CPU generates a transmission start source signal (reception timing signal) at regular intervals, the data output can be updated at regular intervals.
JP 2003-224552 A

  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 become obstacles to downsizing the device, and the power line As a result, inductive noise is generated by connecting the signal lines, resulting in sensor malfunction.

  Here, the main body configuration of a conventional digital multifunction peripheral is shown in FIG. 16, 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. The exposure lamp 122 includes a fluorescent lamp, a halogen lamp, and the like, and irradiates a document on a document placement glass (document table) 126 while moving in a 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 synchronization with 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 that has been transferred 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. 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 taking 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 bottom plate 1 is moved by the movement of the belt.
82 is controlled to rise and fall. The transfer paper at the standby position is conveyed to the paper feed roller pair 184 by the pickup roller 185, and the transfer paper is conveyed to the conveyance path while preventing double feeding as in the case of main body paper feeding. 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.

  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 such as a discharge destination of processing that is interrupted during normal processing.

  Usually, the trays for 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 reversing process timing and the like are detected and used for controlling the driving timing of the flapper and the reversing 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.

  However, in the above-described paper feed stage or the like, it is necessary to supply power to a plurality of motors. Along with the signal lines for data communication, a plurality of drive circuits such as at least a logic power supply and a motor drive power supply are provided to each drive circuit. Power supply will be performed, and even if the data signal lines can be reduced by serial communication, it is impossible to greatly improve the volume ratio of the bundled wires in the equipment.

  In order to improve these, domestic home appliance manufacturers are participating in the “Echo Net” and “High Speed Power Line Communication Council” to form a network using existing commercial power supply lines. Focusing on power line communication that has been established to enable network communication between power equipment and home appliances, the “Echo Net” etc. are equipment / home appliances using commercial power supply lines. In contrast to what is intended to construct a general network between the devices, power line communication is used for the motor drive system, in particular, using the power line in the equipment.

  Accordingly, an object of the present invention is to provide an image forming apparatus capable of controlling a motor while enabling a reduction in the volume ratio of the bundled wires in the device and a reduction in the occupancy ratio of the connectors on each circuit board due to the reduced bundled wires. It is to provide.

  Another object of the present invention is to generate a control clock for driving a motor from a carrier wave and received data at the time of communication on the receiving device side, thereby enabling acceleration / deceleration control and constant speed control of each motor. An object of the present invention is to provide an image forming apparatus capable of controlling a motor from a main body controller using only a supply line.

  The present invention relates to a modulation circuit for converting data into a predetermined data format for a power supply line, carrier frequency setting means for setting a carrier used for the modulation circuit to an arbitrary frequency, and generation by the modulation circuit A power line communication transmitter comprising: a transmission coupling means for superimposing the transmitted communication signal on the power line; and a signal received from the transmitter for extracting communication data superimposed from the power supply line A receiving and coupling means; and a communication signal from the receiving and coupling means, and a means for detecting a carrier frequency according to the modulation means. The carrier signal is demodulated and a carrier frequency division ratio is determined according to the data. The power line communication receiving device is characterized by comprising control CLK generation means for generating a CLK signal for motor drive control.

  Further, in the case of a multi-carrier (multi-carrier) system as a modulation system having a configuration different from that of the communication apparatus, the first or second frequency for data transmission is used as a carrier wave, and the third or fourth for control CLK. The power line communication apparatus is characterized in that the carrier wave has a frequency of a predetermined frequency.

  Furthermore, the transmission means varies the frequency for superimposing the average value of the supply voltage of the power supply in accordance with the transmission data used as the control CLK, and has a combined configuration with a low-pass filter on the reception side, By adopting a configuration in which the average value of the power supply voltage is varied in accordance with the drive CLK, an image forming apparatus that can optimize the generated torque of a stepping motor or the like in particular is configured.

  According to the present invention, when power line communication is performed, a control CLK signal to the motor drive device is generated based on the carrier wave, and data communication is enabled, thereby greatly reducing the number of bundles in the image forming apparatus. It becomes possible to do. Further, torque control more optimal than level control of the motor drive voltage is possible.

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

<Embodiment 1>
The configuration diagram of the first 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 operation of the image forming apparatus is performed as described above. Here, a power line communication method to which the present invention is applied to each motor drive unit of the image forming apparatus will be described.

  The power line communication system includes a transmitting device 101 that transmits data and a receiving device 201 that receives data.

  The transmission apparatus 101 includes an interface 111 for transmitting / receiving command data to / from the motor driving apparatus from the controller 1000 of the image forming apparatus, modulation / demodulation means 112 for data transmitted / received to / from the motor driving apparatus, and motor driving from a DC power source A coupling means 113 for superimposing (separating) modulation (demodulation) data on a DC power supply line for supplying power to the apparatus. 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. In addition, 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 apparatus 201 also generates a clock signal for generating a driving pulse from a carrier wave used for data modulation, and a demodulator 212 to demodulate the signal and output the serial-parallel converter 213. Drive pulse generation means 215 for generating a drive pulse for driving the motor 222 according to the pulse division set value is provided.

  A predetermined DC power source of the DC power source 3 is supplied to the motor 222 via the power supply line, and is required in the receiving device 201 and the driving circuit 221 by a DC-DC converter (not shown) in the motor driving device. Used after being converted to voltage.

  Here, a method for converting a carrier wave into a CLK signal will be described.

  As means for modulating the data signal to be superimposed on the power line, amplitude modulation (AM: Amplitude Modulation, for digital modulation, ASK: Amplitude Shift Keying) and frequency modulation (FM: Frequency Modulation, for digital modulation) as shown in FIG. A technique such as FSK (Frequency Shift Keying) is employed. FIG. 4 shows generation of a modulation signal during amplitude modulation, and FIG. 5 shows a method of generating a frequency modulation signal.

  In the present embodiment, a method of generating a CLK signal in the CLK conversion unit 214 will be described in the case of using the amplitude modulation shown in FIG.

  As shown in FIG. 4, depending on the modulated data, the amplitude may be “0” when the data is “0”. Here, as shown in FIG. 5 ((a) to (c)). A carrier wave of communication data received using a digital processing unit (not shown) included in the demodulation / modulation unit 212 is Fourier-transformed (in a DSP programming environment, a fast Fourier transform FFT function is prepared as a general function. By converting the time-series data of the carrier wave into frequency domain data, the frequency f0 of the carrier wave input to the modulator is obtained, and the CLK signal having a cycle setting that matches the frequency is set, for example, the cycle setting. It is set by up / down count, and it is generated by using the compare match function with the comparison value to be an arbitrary duty. In this regard, if the amplitude does not become “0” at the time of data “0”, a predetermined threshold value is simply set by a comparison operation as shown in FIGS. It is also possible to generate the CLK signal directly from. As a result, the CLK signal generated by the CLK conversion means 214 is converted into a pulse signal having a frequency corresponding to the communication data as shown in FIG. 6 in the drive pulse generation means 215 using the demodulated communication data as the division ratio setting data. Will be converted. As a result, the acceleration / deceleration drive pattern of the motor 222 is generated according to the instruction data from the controller, and the motor 222 is driven by the drive circuit 221.

  By adopting the configuration as described above, the control signal is extracted from the communication data superimposed on the power supply line, so that in addition to the conventional power supply line, the CLK signal line for motor drive control, the signal for drive current switching control Lines, drive mode (full step / half step) switching signals, motor drive device status monitoring, signal lines for various sensor signals, etc. are required only for power supply lines It is possible to achieve a significant reduction in the number of bundled wires.

  In addition, according to the modulation method, motor drive noise can be expected to be prevented from being erroneously detected by induction noise between bundled wires in various sensor outputs, and the bundled wire routing freedom is greatly increased along with the bundle wire volume reduction effect. The advantage of becoming.

<Embodiment 2>
The second embodiment is a case where frequency modulation is used, whereas the first embodiment uses amplitude modulation, and FIG. 7 shows a configuration block diagram. In the circuit configuration, the CLK conversion unit 214 of the first embodiment is not necessary, and a drive pulse is generated by a method as shown in FIG.

  As described above, the frequency modulation performs modulation / demodulation by assigning frequencies f0 and f1 to 0/1 of the digital data as shown in FIG. Here, the frequency f0 is assigned as data “0”, the other frequency is set as data “1”, and the frequency f1 of the carrier wave of data “1” is arbitrarily variable (f1-1 to f1-2). did. Thereby, the drive pulse generation means 215 generates a drive pulse from the frequency ratio (or difference) between the carrier waves f0 and f1. For this reason, the modulation / demodulation means 112 on the transmission apparatus 101 side performs modulation after setting the frequency of the carrier wave f1 based on the command value from the controller 10.

  With the configuration as described above, it is possible to make it more difficult for a communication error or the like to occur with respect to noise such as a power supply line than communication using only amplitude modulation.

  Furthermore, by making it possible to appropriately set the amplitude value of the carrier wave according to the voltage supplied by the power supply line, for example, in the case of a power supply voltage of 24V, When the carrier wave 1 and the carrier wave 2 are superimposed, the effective voltage value of the voltage supplied to the motor changes as shown in FIG. 10 by the high-pass filter (or low-pass filter) 231 set according to the frequency of the carrier wave 2. In the case of a motor or the like whose torque changes depending on the driving frequency, such as a stepping motor, it is possible to suppress a decrease in torque by correcting the power supply voltage.

<Embodiment 3>
The third embodiment is a development of the second embodiment, in which a plurality of carrier frequencies are set, and a plurality of motor drive devices can be controlled.

  As shown in FIG. 11, the basic configuration is the same, and for a plurality of motor drive devices, carrier wave 1: f0 is common and carrier wave 2: f1, carrier wave 3: f2,..., Carrier wave N: fn− 1, each of the carriers 2 to N can be controlled to be arbitrarily variable (fn-1-1 to fn-1-2) while limiting a certain frequency width to each of the carriers 2 to N, thereby enabling multiple control.

  In each motor drive control device, a combination of carrier waves to be used is set. As shown in FIG. 12, in the motor drive device 221, as in the second embodiment, carrier waves 1: f0 and carrier waves 2: f1. In the motor driving device 222, the combination of the carrier wave 1: f0 and the carrier wave 3: f2, and in the Nth motor driving device, the combination of the carrier wave 1: f0 and the carrier wave N: fn−1. In combination, a plurality of motor drive devices can be controlled.

  As a result, load control can be performed for each motor drive device used in the image forming apparatus by connecting only the power bundles, and the bundles can be greatly reduced.

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 modulated signals in amplitude modulation (ASM) and frequency modulation (FMS). It is a schematic diagram of data modulation by amplitude modulation (ASM). It is a schematic diagram of data modulation by frequency modulation (FSM). It is a schematic diagram which produces | generates CLK from the carrier wave in Embodiment 1 of this invention. It is a figure which shows the drive pulse generation method of Embodiment 1 of this invention. It is a block diagram which shows the structural example of the communication system of Embodiment 2 of this invention. It is a figure which shows the production | generation method of the drive pulse in Embodiment 2 of this invention. It is a block diagram which shows the structural example of the communication system in Embodiment 3 of this invention. It is a figure which shows the change method of the power supply voltage by the carrier wave in Embodiment 3 of this invention. It is a block diagram which shows the structural example of the communication system by multiple carriers in Embodiment 3 of this invention. It is a figure which shows the production | generation method of the drive pulse of multiple motor load from the multiple carrier wave of Embodiment 3 of this invention. It is a figure which shows the conventional serial transmission circuit. It is a figure which shows the synchronizing circuit of the conventional serial transmission circuit. It is a figure which shows the conventional serial receiving circuit. 1 is a cross-sectional view of a digital copying machine as an image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Transmission apparatus 111 Interface 112 Demodulation means 113 Coupling means 201 Reception apparatus 211 Coupling means 212 Demodulation / modulation means 213 Serial-apparel conversion means 214 CLK conversion means 215 Drive pulse generation means 221 Drive circuit 1000 Controller

Claims (6)

In an image forming apparatus that performs communication between units by superimposing a carrier wave on a power line,
An image forming apparatus characterized in that, in particular, a motor load driving means demodulates a motor drive control CLK signal and various control signals from a communication carrier wave and communication data, and performs motor drive control based on the demodulation.   2. The image forming apparatus according to claim 1, wherein when the amplitude modulation is used as the control CLK signal generation means, the CLK signal is generated directly from a carrier wave by a comparison means with respect to a predetermined threshold value.   2. The image forming apparatus according to claim 1, wherein the CLK signal is generated by determining the carrier frequency by performing Fourier transform on the modulated signal when amplitude modulation is used as the control CLK signal generating means. .   When the modulation mode of communication is frequency modulation, the frequency of the first carrier wave is fixed, and the frequency of the second carrier wave can be arbitrarily changed, so that the ratio between the first carrier wave and the second carrier wave 2. The image forming apparatus according to claim 1, wherein a motor control CLK is generated from the motor.   When the modulation mode of communication is frequency modulation, the frequency of the first carrier wave is fixed, and the frequency of the nth carrier wave can be arbitrarily changed in the second and subsequent periods. When the first carrier wave and the other carrier wave are not overlapped, a motor control CLK is generated from the ratio of the first carrier wave and the other carrier wave, and each of the plurality of motor driving devices is generated. The image forming apparatus according to claim 1, wherein the control CLK can be generated.   When performing communication by frequency modulation, a high-pass filter or a low-pass filter is connected in series to the power supply line of the motor driving device, and the voltage level of the amplitude value of the carrier wave is at the level of the supplied power supply voltage. 6. The image forming apparatus according to claim 4, wherein the image forming apparatus can be set as appropriate, and the power supply voltage value supplied to the motor driving device can be corrected according to the frequency of a carrier other than the first carrier.

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