Circuit board and image forming apparatus

Abstract

To provide a circuit board that allows a plurality of electronic components exclusively to be mounted thereon, and can reduce the area of a wiring pattern while ensuring the normal operation of a load.SOLUTION: A circuit board 300 allows motor driver ICs 406, 416 to be exclusively mounted on its front face and rear face. The circuit board 300 comprises: a CPU (304) that can generate a first control signal that is input to the motor driver IC 406 to control the logical value of a phase output signal OUTA output from the motor driver IC 406, and a second control signal that is input to the motor driver IC 416 to control the logical value of a phase output signal OUTB output from the motor driver IC 416; and a via VIA1 that connects wiring from which the phase output signal OUTA is output and wiring from which the phase output signal OUTB is output to each other. The logical value of the first control signal and the logical value of the second control signal are in the mutually reverse relationship (DIR signals).SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a circuit board on which electronic components are mounted, and an image forming apparatus such as a printer, a copier, or a multifunction peripheral having such a circuit board.

Background Art

[0002] An image forming apparatus includes a plurality of circuit boards for controlling a plurality of actuators for image formation. The control circuit boards include a circuit board having a function of performing image formation control, a circuit board having a function of performing paper conveyance control, and the like. On each control circuit board, a plurality of electronic components such as an electronic component for performing logical operations, an electronic component for performing drive control, and an electronic component for generating a power supply voltage are mounted according to the function to be realized. The electronic components on the circuit board are connected by wirings such as printed wirings. Each electronic component constitutes an electronic component component that realizes a predetermined function including peripheral electronic components. For example, an electronic component component is constituted by a semiconductor device such as an IC (Integrated Circuit) and peripheral components such as a resistor, a capacitor, and an inductor connected to the input / output terminals of the semiconductor device.

[0003] An image forming apparatus prints an image on a sheet through a plurality of steps such as sheet conveyance, image formation, image transfer to the sheet, and image fixing on the sheet. Therefore, the image forming apparatus needs to control various actuators such as an optical sensor, a temperature sensor, a motor, and a solenoid. The control circuit board mounted on the image forming apparatus has a plurality of electronic components mounted thereon for actuator control. For example, a driver board for driving a motor has a semiconductor device (motor driver IC) for generating a drive signal for the motor based on a control signal input from a controller in order to appropriately control the motor (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the prior art, in order to arrange more electronic components, the electronic components are arranged on both sides of the circuit board. However, the logical values of the control signals supplied to those electronic components have not been studied. Therefore, it has been difficult to obtain appropriate signal output depending on the arrangement situation of the electronic components.

[0006] In view of the above problems, the main object of the present invention is to provide a circuit board capable of outputting an appropriate signal.

Means for Solving the Problems

[0007] The circuit board of the present invention is a circuit board on which a first electronic component can be mounted on a first surface and a second electronic component can be mounted on a second surface different from the first surface, and a first control signal input to the first electronic component for controlling the logical value of an output signal output from the first electronic component, and a second control signal input to the second electronic component for controlling the logical value of an output signal output from the second electronic component, a control means capable of generating, a wiring through which the output signal from the first electronic component is output, and a first via connecting the wiring through which the output signal from the second electronic component is output, and the logical value of the first control signal and the logical value of the second control signal are in a reverse relationship with each other.

Effects of the Invention

[0008] According to the present invention, a plurality of electronic components can be exclusively mounted on the circuit board, and the area of the wiring pattern can be suppressed while ensuring the normal operation of the load.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The configuration and circuit of the apparatus described in this embodiment are examples for explaining the proposed content, and are not limited to the described content.

[0011] (Configuration of the image forming apparatus) FIG. 1 is a system configuration diagram of an image forming apparatus having the circuit board of this embodiment. Unless otherwise specified, it goes without saying that the image forming apparatus 100 may be a system composed of a plurality of devices connected via a network as long as the functions of the image forming apparatus 100 are executed.

[0012] The image forming apparatus 100 of this embodiment is communicably connected to a host computer 101 via a network 105. The network 105 is composed of communication lines such as a LAN (Local Area Network), a WAN (Wide Area Network), and a public line. The image forming apparatus 100 and the host computer 101 may be respectively connected to the network 105 in plurality. The host computer 101 generates a print job based on input information from a user acquired by an input device (not shown), and transmits the generated print job to the image forming apparatus 100 via the network 105.

[0013] The image forming apparatus 100 includes a controller board 110, a storage 115, a paper feeding unit 140, a printer engine 150, and an operation panel 180. The controller board 110, the storage 115, the paper feeding unit 140, the printer engine 150, and the operation panel 180 are connected to each other via a system bus 116 so as to be communicable with each other.

[0014] The controller board 110 includes an I / O control unit 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, and a CPU (Central Processing Unit) 114. The I / O control unit 111, the ROM 112, the RAM 113, and the CPU 114 are electronic components mounted on a circuit board. The controller board 110 functions as a main control unit of the image forming apparatus 100, performs various data processes, and controls the operation of the entire image forming apparatus 100. Note that the circuit board is, for example, a printed wiring board on which printed wiring is formed.

[0015] The I / O control unit 111 controls communication with external devices such as a host computer 101 via a network 105. The CPU 114 controls operations such as image forming processes by the image forming apparatus 100 by executing computer programs stored in the ROM 112 and the storage 115. The RAM 113 provides a work area when the CPU 114 executes processes and stores temporary data and the like. The storage 115 stores large-capacity data such as image data and print data temporarily or long-term. For example, the storage 115 stores image data for generating adjustment images for adjusting image forming conditions. The storage 115 is a large-capacity storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). Computer programs such as a startup program, a control program, and an operating system executed by the CPU 114 are stored in the ROM 112 and the storage 115.

[0016] The operation panel 180 is a user interface including an input interface and an output interface. The input interface is, for example, a keyboard button, a touch panel, etc. The output interface is a display, a speaker, etc. The operation panel 180 receives instructions, etc. according to the user's operation and inputs them to the CPU 114. The CPU 114 controls the operation of the image forming apparatus 100 according to the instructions. Also, the operation panel 180 displays the state of the image forming apparatus 100 and various setting screens according to the instructions from the CPU 114.

[0017] The paper feeding unit 140 includes a paper feeding device composed of one or more paper feeding stages and the entire conveying unit that conveys the paper from the paper feeding stage to the paper discharging unit. The paper feeding unit 140 feeds the paper one by one from the paper feeding stage according to the instruction from the CPU 114.

[0018] The printer engine 150 includes an image forming unit 152, a printing position control unit 153, an image position detection unit 154, a fixing unit 260, and an image reading unit 290. The image forming unit 152 forms an image (toner image) on the paper fed by the paper feeding unit 140. The fixing unit 260 fixes the image (toner image) on the paper. The image reading unit 290 reads the adjustment image printed on the paper. The image position detection unit 154 detects the position of the image printed on the paper based on the reading result of the adjustment image by the image reading unit 290. The printing position control unit 153 controls the position of the image printed on the paper based on the position of the image detected by the image position detection unit 154.

[0019] Figure 2 is a configuration diagram of the image forming apparatus 100. The image forming apparatus 100 includes an operation panel 180 at the upper part of the housing 201. Inside the housing 201, the controller board 110, the storage 115, the paper feeding unit 140, and the printer engine 150 shown in FIG. 1 are provided. The printer engine 150 includes each mechanism constituting the engine unit and an engine control unit that controls the processing by each mechanism. Each mechanism constituting the engine unit includes an optical processing mechanism for forming an electrostatic latent image, visualizing the electrostatic latent image, and transferring the visualization to the paper S, and a fixing processing mechanism for fixing the toner image transferred to the paper S.

[0020] The image forming unit 152 (see FIG. 1) of the printer engine 150 corresponds to an optical processing mechanism and includes a Y station 220, an M station 221, a C station 222, a K station 223, an intermediate transfer belt 252, and a secondary transfer outer roller 251. The Y station 220, the M station 221, the C station 222, and the K station 223 have the same configuration, and only differ in the color of the image to be formed. The Y station 220 forms a yellow image. The M station 221 forms a magenta image. The C station 222 forms a cyan image. The K station 223 forms a black image. Here, the configuration of the Y station 220 will be described, and the descriptions of the configurations of the M station 221, the C station 222, and the K station 223 will be omitted.

[0021] The Y station 220 includes a photosensitive drum 205, a charger 211, an exposure device 207, and a developing device 212. The photosensitive drum 205 is a drum-shaped photoreceptor having a photosensitive layer on its surface. The charger 211 uniformly charges the surface of the photosensitive drum 205 that rotates about the drum axis. The exposure device 207 scans the charged surface of the photosensitive drum 205 with laser light modulated according to image data.

[0022] The exposure device 207 includes a laser driver that controls the emission of a semiconductor laser (not shown) according to image data acquired from the controller board 110 (CPU 114), a rotating polygon mirror 208, and a reflection mirror 209. The laser light emitted from the semiconductor laser moves in the main scanning direction according to the rotation of the rotating polygon mirror 208 and is guided to the surface of the photosensitive drum 205 by the reflection mirror 209. As a result, the laser light scans the surface of the photosensitive drum 205 in the drum axis direction. When the surface of the photosensitive drum 205 is exposed, an electrostatic latent image is formed.

[0023] The developing unit 212 visualizes the electrostatic latent image with the toner of the corresponding color to form a toner image on the surface of the photosensitive drum 205. A yellow toner image is formed on the photosensitive drum 205 of the Y station 220. A magenta toner image is formed on the photosensitive drum 205 of the M station 221. A cyan toner image is formed on the photosensitive drum 205 of the C station 222. A black toner image is formed on the photosensitive drum 205 of the K station 223.

[0024] The intermediate transfer belt 252 is an endless belt wound around a plurality of rollers such as the secondary transfer inner roller 240. The intermediate transfer belt 252 rotates in the clockwise direction in the figure. The toner images of each color formed on each photosensitive drum 205 are transferred so as to be superimposed on the rotating intermediate transfer belt 252. The transfer of the toner image from the photosensitive drum 205 to the intermediate transfer belt 252 is performed by applying a bias voltage having a polarity opposite to that of the toner image to the intermediate transfer belt 252. Thereby, the intermediate transfer belt 252 carries a full-color toner image. The intermediate transfer belt 252 rotates to convey the carried toner image to the secondary transfer section composed of the secondary transfer inner roller 240 and the secondary transfer outer roller 251.

[0025] The paper feeding unit 140 corresponds to a paper feeding mechanism for the paper S, and includes a storage bin 210 which is a paper feeding stage for storing the paper S, a conveyance path, conveyance rollers, and the like. The paper feeding unit 140 conveys the paper S from the storage bin 210 to the secondary transfer section one by one. The secondary transfer section sandwiches and conveys the intermediate transfer belt 252 and the paper S by the secondary transfer inner roller 240 and the secondary transfer outer roller 251. At this time, by applying a bias voltage having a polarity opposite to that of the toner image to the secondary transfer outer roller 251, the toner image is transferred from the intermediate transfer belt 252 to the paper S.

[0026] The sheet S onto which the toner image has been transferred is conveyed to a fixing unit 260 which is a fixing processing mechanism. The fixing unit 260 includes a fixing roller 261 having a heat source inside, a pressure roller 262 biased toward the fixing roller 261 side, and a circuit board 300 that controls the fixing process by the fixing unit 260. The fixing unit 260 fixes the toner image onto the sheet S by sandwiching and conveying the sheet S onto which the toner image has been transferred between the fixing roller 261 and the pressure roller 262. At that time, the fixing roller 261 heats and melts the toner image and presses the sheet S between it and the pressure roller 262.

[0027] As described above, an image is printed on the sheet S. In the case of double-sided printing, the sheet S with an image printed on the first side (front surface) is conveyed to the secondary transfer unit again via the reverse path 270. By being conveyed to the secondary transfer unit via the reverse path 270, the printed surface of the image on the sheet S is reversed. The sheet S with the printed surface of the image reversed has an image printed on the second side (back surface) different from the first side by the secondary transfer unit and the fixing unit 260.

[0028] The sheet S on which the image has been printed passes through an image reading unit 290 provided on the downstream side of the fixing unit 260 in the sheet conveyance direction and is discharged out of the image forming apparatus 100. The image reading unit 290 is used for reading the adjustment image when the image formed on the sheet S is an adjustment image for image forming conditions.

[0029] (Circuit board) In order to perform the image forming process as described above, the image forming apparatus 100 includes various types of actuators (loads) such as motors and sensors inside. The actuators are connected to a circuit board on which control electronic components are mounted. Each electronic component mounted on the circuit board is connected by a conducting wire. The circuit board of the present embodiment is, for example, a printed wiring board using printed wiring for the conducting wire.

[0030] The electronic components control the operation of the actuator. For this purpose, a large number of circuit boards are provided in the image forming apparatus 100 corresponding to the actuator. One circuit board controls one or more actuators. The circuit board is controlled by the CPU 114 of the controller board 110. Note that the controller board 110 on which the CPU 114 is mounted is also an example of a circuit board.

[0031] FIG. 3 is a configuration diagram of a circuit board 300 provided in the fixing unit 260. A plurality of motors 309 to 311 in the fixing unit 260 and a plurality of sensors 312 to 314 in the fixing unit 260 are electrically connected to the circuit board 300. The motors 309 to 311 are actuators (loads) whose operations are controlled by the circuit board 300.

[0032] The motor 309 is a drive source for driving the fixing roller 261 which is a rotating body. The motor 310 is a drive source for urging the pressure roller 262 toward the fixing roller 261. The motor 311 is a drive source for driving a roller which is a rotating body that conveys the sheet S after the fixing process to the subsequent stage. The sensor 312 is a detector for detecting the sheet S conveyed to the fixing unit 260. The sensor 313 is a temperature detector for detecting the temperature of the fixing roller 261. The sensor 314 is a detector for detecting the sheet S after the fixing process.

[0033] The circuit board 300 realizes various functions with a plurality of electronic components. In the example of FIG. 3, it includes an AC-DC converter 302 used to generate a predetermined DC voltage from an AC voltage and a DC-DC converter 303 for converting the voltage value of the DC voltage. Further, the circuit board 300 includes a CPU 304, an ASIC (Application Specific Integrated Circuit) 305, and motor driver ICs 306 to 308 used for controlling the actuator. The circuit board 300 has mounted thereon, as electronic components, a plurality of semiconductor devices (hereinafter referred to as "ICs") as described above and peripheral electronic components corresponding to the ICs.

[0034] The AC-DC converter 302 generates a DC power supply voltage having a predetermined voltage value based on the AC power supplied from the commercial power supply 301. The DC-DC converter 303 generates a DC power supply voltage having a voltage value different from that of the power supply voltage based on the power supply voltage supplied from the AC-DC converter 302. The power supply voltage generated by the DC-DC converter 303 is supplied to the CPU 304, the ASIC 305, etc. The CPU 304 and the ASIC 305 operate with the power supply voltage supplied from the DC-DC converter 303. The power supply voltage output from the AC-DC converter 302 is also supplied to electronic components and motors 309 to 311 that operate at a voltage value different from that of the CPU 304 and the ASIC 305.

[0035] The CPU 304 is connected to the motor driver ICs 306 to 308 and the respective sensors 312 to 314 via the ASIC 305. The CPU 304 acquires the detection results from each of the sensors 312 to 314, and detects the state of the fixing unit 260 based on the detection results. The CPU 304 controls the driving of each of the motors 309 to 311 by controlling each of the motor driver ICs 306 to 308 via the ASIC 305 according to the detected state of the fixing unit 260. In this way, the CPU 304 and the ASIC 305 control the operation of the fixing unit 260.

[0036] Since the circuit board 300 is provided in the fixing unit 260, it controls the operation of the fixing unit 260. Similarly, other circuit boards provided in the image forming apparatus 100 also control the operation of the corresponding components. Each circuit board (including the circuit board 300 and other circuit boards) in the image forming apparatus 100 is communicably connected to the controller board 110. Communication is possible between each circuit board via the controller board 110. Each circuit board appropriately controls the components in the image forming apparatus 100 while sharing information regarding the detection results of each sensor and the control state of the load with each other.

[0037] A large number of electronic components are mounted on the circuit board. However, due to various reasons such as distribution, environment, and accidents, there may be a situation where it is difficult to procure at least some of the electronic components. In order to address the situation where difficult-to-procure electronic components (which may be referred to as "first planned parts" for convenience) occur, electronic components with the same or similar shapes and specifications may be prepared as substitute parts (which may be referred to as "second planned parts" for convenience) for each electronic component. If there are electronic components that cannot be procured, the manufacturing of the circuit board 300 is continued by mounting the substitute parts of the electronic components on the circuit board.

[0038] However, for example, in the circuit board 300, specific ICs such as the IC of the DCDC converter 303 and the motor driver ICs 306, 307, 308, etc. may require specific peripheral components during use. Also, the number, arrangement, array, or electrical specifications of the IC terminals may be different, and there may be no replaceable ICs. In such cases, in order to address the situation where it is difficult to procure each IC, another electronic component component capable of realizing the same function as the electronic component component composed of the IC and the peripheral components is prepared. These electronic component components are exclusively mounted on the circuit board. With this countermeasure method, it is possible to continue the manufacturing of the circuit board 300 in order to mount an IC that can be procured according to the availability of the mounted components.

[0039] When the first planned parts of the electronic components and the second planned parts of the electronic components are exclusively mounted on the circuit board, if they can be mounted on the same surface of the circuit board, the wiring routing becomes complicated and the area occupied by the wiring pattern on the circuit board becomes large. On the other hand, for example, by making it possible to mount the first planned parts on one surface of the circuit board and the second planned parts on the other surface, and making the wiring patterns as common as possible, the area occupied by the wiring patterns can be reduced.

[0040] The circuit board has a determined arrangement of terminals for connection to loads such as actuators. For this reason, the electronic components of the first planned product and the electronic components of the second planned product have the same order of arrangement of terminals for supplying signals and current to the load. There is no problem when the first planned product and the second planned product are exclusively mounted on the same surface of the circuit board. However, when they are mounted on different surfaces, the arrangement of terminals for transmitting signals to the load may be reversed between the first planned product and the second planned product. For example, when the signals transmitted by the electronic components to the load are complementary signals, the arrangement of the terminal for outputting the positive-phase signal and the terminal for outputting the inverted-phase signal of the complementary signal may be reversed between the genuine product and the replacement product depending on the surface on which they are mounted. This will interfere with the normal operation of the load. For example, when the load is a motor, the rotation direction will be reversed between the genuine product and the replacement product.

[0041] The circuit board 300 of the present embodiment has a configuration that can cope with situations where component procurement is difficult, can appropriately control electronic components, and can further suppress the area required for wiring. Hereinafter, the specific circuit configuration and the wiring (wiring pattern) of the circuit board 300 will be described. In this embodiment, the configuration of a motor driver IC for controlling a two-phase bipolar drive stepping motor will be used for the description.

[0042] (Electronic component) FIG. 4 is an explanatory diagram of an electronic component including a motor driver IC and its peripheral components. This electronic component includes a first electronic component 410 including a genuine motor driver IC 406 and a second electronic component 420 including a replacement motor driver IC 416 for the motor driver IC 406. The first electronic component 410 and the second electronic component 420 have equivalent functions and are exclusively mounted on the front and back surfaces of the circuit board 300.

[0043] The first electronic component 410 includes resistors R11, R12, R13 and capacitors C11, C12, C13 in addition to the motor driver IC 406. Resistors R12 and R13 are detection resistors for detecting current. Resistor R11 is a resistor for determining the chopping frequency of the constant current PWM (Pulse Width Modulation) control when controlling the motor current. Capacitors C11, C12, and C13 are provided for noise removal respectively.

[0044] Similarly, the second electronic component 420 includes resistors R21, R22, R23 and capacitors C21, C22, C23 in addition to the motor driver IC 416. Resistors R22 and R23 are detection resistors for detecting current. Resistor R21 is a resistor for determining the chopping frequency of the constant current PWM control when controlling the motor current. Capacitors C21, C22, and C23 are provided for noise removal respectively.

[0045] Control signals branched from the ASIC 305 via the damping resistors R1 to R6 are input to the motor driver ICs 406 and 416. The control signals include an ENABLE signal, a CLK signal, a VREF signal, MODE signals (MODE_1 signal and MODE_2 signal), and a DIR signal, etc. The ENABLE signal is a control signal for enabling the outputs of the motor driver ICs 406 and 416. The CLK signal is a control signal for controlling the speed of the motor. The VREF signal is a control signal for controlling the current value flowing through the motor. The MODE signal is a control signal for controlling the excitation pattern of the motor. The DIR signal is a control signal for controlling the rotation direction of the motor. An inverter 415, which is a logic inversion circuit for inverting the logic of the DIR signal, is provided in the middle of the path for inputting the DIR signal to the motor driver IC 416. Thereby, DIR signals with inverted logic are input to the motor driver IC 406 and the motor driver IC 416.

[0046] In response to commands based on these control signals, motor driver ICs 406 and 416 can drive the motor. The phase output signals OUTA, OUTA*, OUTB, and OUTB*, which are complementary signals output from motor driver ICs 406 and 416, are input to the motor at the shortest distance. The operation of the motor is controlled by these complementary signals input from motor driver ICs 406 and 416.

[0047] The wiring through which the phase output signals OUTA, OUTA*, OUTB, and OUTB* are transmitted usually has a wider wiring width than the wiring through which the control signals are transmitted because a current for driving the motor flows through it. Therefore, the wiring through which the phase output signals are transmitted has a lower degree of freedom in the wiring pattern and tends to have a larger area of the wiring pattern. In order to minimize the area of the wiring through which the phase output signals are transmitted, it is necessary to make the wiring through which the phase output signals are transmitted the shortest distance.

[0048] Furthermore, in this embodiment, motor driver IC 406 and motor driver IC 416 are exclusively mounted on both sides of the circuit board. At this time, in order to minimize the area of the wiring pattern, it is necessary to connect the wiring through which the phase output signals are transmitted at the shortest distance.

[0049] Motor driver IC 406 and motor driver IC 416, which are exclusively mounted, may have different package sizes. In this embodiment, the case where the package size of motor driver IC 416 is larger than that of motor driver IC 406 will be described.

[0050] In addition, the circuit board 300 of the present embodiment has a multilayer structure. Here, a circuit board 300 with a four-layer structure will be described, but it may have any number of layers as long as it is multilayer. The circuit board 300 with a four-layer structure is a double-sided reflow type, and electronic components can be mounted on one of the outermost layers (the first layer) and the other layer (the fourth layer) as mounting surfaces. The motor driver IC 406 and the motor driver IC 416 are exclusively mounted on the surface of the first layer, which is the first surface, and the surface of the fourth layer, which is the second surface. The second layer is a power supply layer and includes a power supply wiring for driving a load that supplies power to the motor driver ICs 406 and 416, a logic power supply wiring that supplies a low voltage to the CPU 304, the ASIC 305, etc. The third layer is a ground layer and is connected to the ground patterns of the first layer and the fourth layer via vias.

[0051] (Mounting area of the circuit board) FIG. 5 is an explanatory diagram of the mounting surface of the circuit board 300. In the present embodiment, the first electronic component 410 is mounted on the first surface (front surface) of the first layer, and the second electronic component 420 is mounted on the second surface (back surface) of the fourth layer. On the mounting surfaces (the first surface and the second surface), a wiring pattern is formed by a conductor such as copper foil, for example, by a printing method. The description of the wiring patterns of the second layer and the third layer is omitted.

[0052] In the present embodiment, as described with reference to FIG. 4, the first electronic component 410 and the second electronic component 420 are exclusively mounted on the front and back surfaces of the circuit board 300. The first electronic component 410 includes the genuine motor driver IC 406. The second electronic component 420 includes the motor driver IC 416, which is a substitute for the motor driver IC 406. The mounting area of the motor driver IC 406 on the front surface and the mounting area of the motor driver IC 416 on the back surface are provided at the same position (coordinate area) facing each other with the circuit board 300 (the second layer and the third layer) interposed therebetween. That is, the mounting area of the motor driver IC 406 and the mounting area of the motor driver IC 416 are provided so as to at least partially overlap when viewed from the normal direction of the surface of the circuit board 300. Wiring patterns (hatched portions) are formed so that the motor driver ICs 406 and 416 can be mounted in these mounting areas.

[0053] The circuit board 300 includes output terminals 501, 502, 503, and 504 for outputting the phase output signals OUTA, OUTA*, OUTB, and OUTB* to the motor. When the motor driver IC 406 is mounted, the phase output signal OUTA is output from the output terminal 501, the phase output signal OUTA* is output from the output terminal 502, the phase output signal OUTB is output from the output terminal 503, and the phase output signal OUTB* is output from the output terminal 504.

[0054] The motor driver IC 416 has the same arrangement of output terminals for outputting the phase output signals as the motor driver IC 406 so that the same wiring pattern can be used when the motor driver IC 416 is mounted on the surface of the circuit board 300. Therefore, when the motor driver IC 416 is mounted on the back surface of the circuit board 300, the arrangement of the output terminals for outputting the phase output signals is opposite to that of the motor driver IC 406.

[0055] That is, the position opposite to the output terminal for outputting the phase output signal OUTB of the motor driver IC 406 is the position of the output terminal for outputting the phase output signal OUTA of the motor driver IC 416. The position opposite to the output terminal for outputting the phase output signal OUTB* of the motor driver IC 406 is the position of the output terminal for outputting the phase output signal OUTA* of the motor driver IC 416. The position opposite to the output terminal for outputting the phase output signal OUTA* of the motor driver IC 406 is the position of the output terminal for outputting the phase output signal OUTB* of the motor driver IC 416. The position opposite to the output terminal for outputting the phase output signal OUTA of the motor driver IC 406 is the position of the output terminal for outputting the phase output signal OUTB of the motor driver IC 416.

[0056] A via VIA3 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTB of the motor driver IC406. A via VIA4 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTB* of the motor driver IC406. A via VIA2 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTA* of the motor driver IC406. A via VIA1 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTA of the motor driver IC406.

[0057] A via VIA1 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTB of the motor driver IC416. A via VIA2 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTB* of the motor driver IC416. A via VIA4 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTA* of the motor driver IC416. A via VIA3 is provided on the wiring connected to the output terminal that outputs the phase output signal OUTA of the motor driver IC416.

[0058] The vias VIA1 to VIA4 can penetrate the circuit board 300 and electrically connect the first layer and the fourth layer of the circuit board 300. Due to such a configuration, the wiring connected to the output terminal that outputs the phase output signal OUTA of the motor driver IC406 and the wiring connected to the output terminal that outputs the phase output signal OUTB of the motor driver IC416 are connected by the via VIA1. The wiring connected to the output terminal that outputs the phase output signal OUTA* of the motor driver IC406 and the wiring connected to the output terminal that outputs the phase output signal OUTB* of the motor driver IC416 are connected by the via VIA2. The wiring connected to the output terminal that outputs the phase output signal OUTB of the motor driver IC406 and the wiring connected to the output terminal that outputs the phase output signal OUTA of the motor driver IC416 are connected by the via VIA3. The wiring connected to the output terminal that outputs the phase output signal OUTB* of the motor driver IC406 and the wiring connected to the output terminal that outputs the phase output signal OUTA* of the motor driver IC416 are connected by the via VIA4.

[0059] By using vias VIA1 to VIA4, the output terminals that output the respective phase output signals of the motor driver IC406 and the output terminals that output the respective phase output signals of the motor driver IC416 are connected by the shortest distance. Therefore, the area of the wiring patterns on the mounting surfaces of the first layer and the fourth layer is suppressed. However, the wirings of the output terminals that output the same phase output signal are not connected to each other. For example, as described above, the wiring connected to the terminal that outputs the phase output signal OUTA of the motor driver IC406 is connected to the wiring connected to the terminal that outputs the phase output signal OUTB of the motor driver IC416. Therefore, as it is, when the motor driver IC416 is mounted, for example, the phase output signal OUTB will be output from the output terminal 501.

[0060] In this way, the phase output signals of the motor driver IC406 and the motor driver IC416 have opposite connection relationships with respect to the motor. This indicates that the rotation direction of the motor is reversed depending on the motor driver IC to be mounted. In the present embodiment, an inverter 415 is connected to the terminal to which the DIR signal of the motor driver IC416 is input so that the DIR signal for controlling the rotation direction of the motor driver IC416 has a logic opposite to that of the DIR signal input to the motor driver IC406.

[0061] By providing the inverter 415, the logical value of the phase output signal of the motor driver IC416 is inverted and becomes the same logic as the phase output signal of the motor driver IC406. Therefore, the motor will rotate in the appropriate rotation direction. Thus, the DIR signal is a control signal that controls the logical values of the respective phase output signals of the motor driver IC406 and the motor driver IC416. In addition to the inverter 415, it is also possible to use transistors, FETs (Field Effect Transistors), etc. as the logic inversion circuit.

[0062] (Modification example) FIG. 6 is a configuration diagram of a modified example of the circuit board 300 provided in the fixing unit 260. This circuit board 300a has a configuration in which a determination bit unit 320 connected to the CPU 304 is provided in the configuration of FIG. 3. The CPU 304 determines the drive control method of each motor 309 to 311 based on the signal output from the determination bit unit 320.

[0063] FIG. 7 is an explanatory diagram of a modified example of an electronic component including a motor driver IC and its peripheral components. Compared with the example of FIG. 4, the determination bit unit 320 is added and the inverter 415 is removed. The determination bit unit 320 exclusively includes two resistors R320 and R321. When the resistor R320 is provided, the determination bit unit 320 outputs the power supply voltage (+3.3 [V]) as a determination signal. When the resistor R321 is provided, the determination bit unit 320 outputs the ground voltage (0.0 [V]) as a determination signal. When the first electronic component 410 is mounted, one of the resistors R320 and R321 is mounted, and when the second electronic component 420 is mounted, the other of the resistors R320 and R321 is mounted. That is, the determination bit unit 320 outputs information indicating which one of the first electronic component 410 and the second electronic component 420 is exclusively mounted when one of them is mounted.

[0064] The CPU 304 acquires a determination signal from the determination bit unit 320 and determines which one of the motor driver IC 406 and the motor driver IC 416 is mounted. For example, when the determination signal acquired by the CPU 304 from the determination bit unit 320 is the power supply voltage, it determines that the logic is high and determines that the motor driver IC 406 is mounted. When the determination signal acquired by the CPU 304 from the determination bit unit 320 is the ground voltage, it determines that the logic is low and determines that the motor driver IC 416 is mounted.

[0065] Based on the determination result, the CPU 304 determines the logic of the DIR signal for controlling the rotation direction of the motor. For example, when the CPU 304 determines that the motor driver IC 416 is connected, as the DIR signal, it outputs a control signal with the logic inverted so that the logic is opposite to that of the motor driver IC 406. By determining the logic of the DIR signal according to the motor driver IC implemented in this way, the phase output signal that is inverted due to the wiring connection relationship is further inverted, and the rotation direction of the motor is appropriately controlled.

[0066] Note that the signal for determining the semiconductor device in which the CPU 304 is implemented is not limited to the determination signal output from the determination bit section 320 as long as it is a signal whose value changes depending on the implemented semiconductor device. Such a signal may have different voltage values when the motor driver IC 406 is implemented and when the motor driver IC 416 is implemented.

[0067] FIG. 8 is a flowchart showing the process of determining the logic of the DIR signal according to the determination signal. This process is performed when driving the motor.

[0068] The CPU 304 acquires the determination signal from the determination bit section 320 (S101). The CPU 304 determines the logic of the acquired determination signal (S102). If the determination signal is the power supply voltage of 3.3 [V], the CPU 304 determines that the logic of the determination signal is high (S102: Y). In this case, the CPU 304 sets the logic of the DIR signal to high (S103). If the determination signal is the power supply voltage of 0.0 [V], the CPU 304 determines that the logic of the determination signal is low (S102: N). In this case, the CPU 304 sets the logic of the DIR signal to low (S104). The DIR signal can be generated by the ASIC 305 according to the instruction of the CPU 304 and is transmitted from the ASIC 305 to the motor driver IC implemented therein. Note that the combination of the logic of the determination signal and the logic of the DIR signal is not limited to this.

[0069] With the above configuration, in the circuit board 300 where two electronic components or two electronic component components having the same function are exclusively mounted, the space on the mounting surface occupied by the wiring pattern can be suppressed. Specifically, two electronic components or two electronic component components can be mounted on the front surface of the circuit board 300, and the other can be mounted on the back surface of the circuit board 300, and they are exclusively mounted. Since the control signals for controlling the load are output from the same terminal of the circuit board 300, the arrangement of the terminals for outputting the control signals of the two electronic components becomes almost the same. Each terminal of the two electronic components is connected by a via penetrating the circuit board 300 and is connected to the same terminal of the circuit board 300. Due to such a configuration, the area of the wiring pattern can be suppressed.

[0070] The control signals output from the two electronic components are complementary signals. Therefore, there are two terminals for the positive-phase signal and the negative-phase signal for outputting the control signals. Since the electronic components are exclusively mounted on the front and back surfaces of the circuit board 300, the arrangement of the terminals for the positive-phase signal and the terminals for the negative-phase signal is interchanged depending on the mounted electronic components. That is, when mounted on the same surface, the arrangement of the terminals for the positive-phase signal and the terminals for the negative-phase signal is the same for the two electronic components, but since one is mounted on a different surface, the arrangement of the terminals for the positive-phase signal and the terminals for the negative-phase signal is reversed.

[0071] In this case, the terminal for the positive-phase signal of the electronic component mounted on the front surface of the circuit board 300 and the terminal for the negative-phase signal of the electronic component mounted on the back surface are connected by a via. Similarly, the terminal for the negative-phase signal of the electronic component mounted on the front surface of the circuit board 300 and the terminal for the positive-phase signal of the electronic component mounted on the back surface are connected by a via. Therefore, depending on the mounted electronic components, the logic of the control signal transmitted from the circuit board 300 to the load is reversed. This interferes with the normal operation of the load. When the load is a motor, the motor will rotate in the reverse direction.

[0072] To prevent this, in the present embodiment, the electronic component mounted on the back surface is controlled so that the logic of the positive-phase signal and the negative-phase signal is reversed. By such control, the load operates normally. When the load is a motor, the motor rotates in the normal direction. Therefore, in the present embodiment, even when two electronic components are exclusively mounted on both sides of the circuit board 300, it is possible to maintain the normal operation of the load while suppressing the area of the wiring pattern.

[0073] In the embodiment described above, an example in which the first planned product and the second planned product are exclusively mounted on both sides of the circuit board has been taken. However, the application range of the present technology is not limited to such a form. For example, when platformizing the development of a plurality of products having different functions, two electronic components may be exclusively mounted according to the functions required for the products.

[0074] Furthermore, the present technology may be applied to a form in which both of the two electronic components are mounted. For example, the two electronic components may operate exclusively according to the operating status of the device. The present technology is also effective in such a case.

Claims

1. A circuit board on which a first electronic component can be mounted on a first surface and a second electronic component can be mounted on a second surface different from the first surface, control means capable of generating a first control signal input to the first electronic component to control the logical value of an output signal output from the first electronic component and a second control signal input to the second electronic component to control the logical value of an output signal output from the second electronic component; a first via connecting a wiring through which the output signal from the first electronic component is output and a wiring through which the output signal from the second electronic component is output; characterized in that the logical value of the first control signal and the logical value of the second control signal are in a reverse relationship with each other. Circuit board.

2. The first electronic component has a first terminal that outputs a positive-phase signal of a first complementary signal as the output signal, The second electronic component is characterized by having a second terminal that outputs a positive-phase signal of a second complementary signal as the output signal. The circuit board according to claim 1.

3. Further comprising a second via, The first electronic component has a third terminal that outputs an inverted-phase signal of the first complementary signal as the output signal, The second electronic component has a fourth terminal that outputs an inverted-phase signal of the second complementary signal as the output signal, The second via is connected to the third terminal and the fourth terminal. The circuit board according to claim 2.

4. The arrangement of the first terminal and the third terminal and the arrangement of the second terminal and the fourth terminal are provided so as to be reversed when the first electronic component and the second electronic component are mounted on different surfaces. The circuit board according to claim 3.

5. The control means is characterized by having a logic inversion means that receives the first control signal and generates the second control signal by inverting the logic value of the received first control signal. The circuit board according to claim 1.

6. The output signal output from the first electronic component and the output signal output from the second electronic component are signals for controlling the rotation of a motor. The circuit board according to claim 1.

7. When the first electronic component is mounted, the control means transmits the first control signal to the first electronic component so as to control the rotation direction of the motor in a first direction. When the second electronic component is mounted, the control means transmits the second control signal to the second electronic component so as to control the rotation direction of the motor in a second direction opposite to the first direction. The circuit board according to claim 6.

8. The circuit board further comprises a determination means for outputting a determination signal indicating which of the first electronic component and the second electronic component is mounted. The circuit board according to claim 1.

9. The control means transmits either the first control signal or the second control signal based on the determination signal obtained from the determination means. The circuit board according to claim 8.

10. The determination means outputs the determination signal of a first voltage value when the first electronic component is mounted, and outputs the determination signal of a second voltage value different from the first voltage value when the second electronic component is mounted. The circuit board according to claim 8.

11. The mounting area of the first electronic component and the mounting area of the second electronic component at least partially overlap when viewed from the normal direction of the first surface. The circuit board according to claim 1.

12. Characterized in that the first electronic component and the second electronic component are exclusively mounted. The circuit board according to claim 1.

13. A load for performing image formation, A first electronic component can be mounted on a first surface, a second electronic component having the same function as the first electronic component can be mounted on a second surface different from the first surface, the first electronic component and the second electronic component are exclusively mounted, and the operation of the load is controlled by the mounted electronic components. The circuit board according to claim 1, characterized by comprising: An image forming apparatus.

14. The load is a motor, The output signal output from the first electronic component and the output signal output from the second electronic component are signals for controlling the rotation of the motor. The image forming apparatus according to claim 13.

15. When the first electronic component is mounted, the control means transmits the first control signal to the first electronic component so as to control the rotation direction of the motor in a first direction. When the second electronic component is mounted, the control means transmits the second control signal to the second electronic component so as to control the rotation direction of the motor in a second direction opposite to the first direction. The image forming apparatus according to claim 14.

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