Circuit board, and image forming apparatus

Abstract

To solve the problem in which: an IC cannot be replaced with another IC replaceable with the IC.SOLUTION: A circuit board 300 has an IC 10 and an IC 20 exclusively mounted thereon and is used for achieving a predetermined function, and the circuit board has: a first conductor pattern formed to electrically connect an electrical part component 3031 including the IC 10 mounted on one face of the circuit board 300 and a common part; vias electrically connected with the first conductor pattern; and a second conductor pattern formed to electrically connect an electrical part component 3032 including the IC 20 mounted on the other face of the circuit board 300 and the common part mounted on one face through the vias.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a printer, a copier, or a multifunction peripheral, having a circuit board on which electrical components for operating built-in actuators and other components are mounted. [Background technology]

[0002] The image forming apparatus includes a plurality of control circuit boards for controlling a plurality of actuators for image formation. A plurality of electric components, such as an electric component for performing logical operations, an electric component for performing drive control, and an electric component for generating a power supply voltage, are mounted on the control circuit board. Each electric component constitutes an electric component component that realizes a predetermined function together with surrounding electric components. For example, an electric component component is constituted by an integrated circuit (IC) and surrounding electric components such as resistors, capacitors, and inductors that are connected to input / output terminals of the IC.

[0003] Circuit boards are manufactured by procuring and mounting many electrical components. However, due to various reasons such as distribution, the environment, and accidents, it can become difficult to obtain electrical components. For example, a supply shortage of ICs has become a problem in recent years. To avoid such situations, for each electrical component, replaceable parts with the same function and the same or similar shape and specifications are investigated in advance, and when a problem occurs in procuring parts, the replaceable parts are procured. The production of circuit boards continues using the replaceable parts.

[0004] An image forming apparatus prints an image on paper through multiple processes such as paper transport, image formation, image transfer onto paper, and fixing of the image onto the paper. To achieve this, the image forming apparatus needs to control a wide variety of actuators such as optical sensors, temperature sensors, motors, and solenoids. A control circuit board mounted on the image forming apparatus is equipped with multiple ICs for controlling the actuators. For example, a motor driver board that drives a motor has an 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). In addition, multiple control circuit boards themselves are provided within the image forming apparatus.

[0005] In a control circuit board, the voltage value required may differ depending on the actuator connected. For this reason, electrical components for generating a plurality of voltages that generate different voltage values ​​are mounted on the circuit board. In such a configuration, power supply voltages of a plurality of different voltage values ​​are generated within the control circuit board. DC-DC converter ICs with low heat loss are widely used as electrical components for generating voltages (Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2022-6639 [Patent Document 2] JP 2021-164356 A Summary of the Invention [Problem to be solved by the invention]

[0007] DC-DC converter ICs and motor driver ICs often require peripheral components for normal operation. In addition, DC-DC converter ICs and motor driver ICs often have different terminal functions and electrical specifications for each IC. For this reason, even if you replace an IC with another IC, the required peripheral components, terminal functions, voltage values, etc. are different, so there is a high possibility that normal operation will not be guaranteed.

[0008] Therefore, a circuit board for realizing a specified function is mounted with electrical components consisting of an IC and peripheral parts (electrical components) that complement the functions of the IC. Furthermore, the wiring (conductor pattern) on the circuit board is often specific to the IC. When replacing an IC with another IC, peripheral parts and wiring (conductor pattern) that correspond to the IC to be replaced are required. In other words, when replacing an IC with another IC, it is necessary to start from the design of the circuit board. Therefore, it is not easy to replace an IC on a circuit board for realizing a specified function.

[0009] In view of the above-mentioned problems, an object of the present invention is to provide a circuit board that enables an IC to be easily replaced with another IC that can replace the IC. [Means for solving the problem]

[0010] The circuit board of the present invention is a circuit board on which a first integrated circuit and a second integrated circuit different from the first integrated circuit are exclusively mounted and used to realize a predetermined function, and is characterized in having: a first mounting portion provided on a first surface of the circuit board and to which a terminal of the first integrated circuit is attached; a first conductor pattern formed on the first surface so as to electrically connect the first mounting portion to an electrical component mounted on the first surface; a via electrically connected to the first conductor pattern; a second mounting portion provided on a second surface different from the first surface of the circuit board and to which a terminal of the second integrated circuit is attached; and a second conductor pattern formed on the second surface so as to electrically connect the second mounting portion to the electrical component mounted on the first surface via the via. Effect of the Invention

[0011] According to the present invention, an IC can be easily replaced with another IC that can replace the IC. [Brief description of the drawings]

[0012] [Figure 1]FIG. 1 is a system configuration diagram of an image forming apparatus. [Diagram 2] FIG. 1 is a diagram illustrating the configuration of an image forming apparatus. [Diagram 3] FIG. [Figure 4] Circuit diagram of a DCDC converter. [Diagram 5] An explanatory diagram of a DC-DC converter on a circuit board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations and circuits of the devices described in the present embodiment are examples for explaining the proposed contents, and the present invention is not limited to the described contents.

[0014] (Configuration of Image Forming Apparatus) 1 is a system configuration diagram of an image forming apparatus having a circuit board according to the present embodiment. Unless otherwise specified, it goes without saying that the image forming apparatus 100 may be a system made up of multiple devices connected via a network, as long as the functions of the image forming apparatus 100 are executed.

[0015] The image forming apparatus 100 of this embodiment is communicatively connected to a host computer 101 via a network 105. The network 105 is configured with communication lines such as a local area network (LAN), a wide area network (WAN), and a public line. A plurality of image forming apparatuses 100 and a plurality of host computers 101 may be connected to the network 105. The host computer 101 generates a print job and transmits the print job to the image forming apparatus 100 via the network 105.

[0016] The image forming apparatus 100 includes a controller board 110, a storage 115, a paper feed unit 140, a printer engine 150, and an operation panel 180. The controller board 110, the storage 115, the paper feed 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 able to communicate with each other.

[0017] The controller board 110 includes an I / O control unit 111, a Read Only Memory (ROM) 112, a Random Access Memory (RAM) 113, and a Central Processing Unit (CPU) 114. The I / O control unit 111, the ROM 112, the RAM 113, and the CPU are mounted on a circuit board. The controller board 110 functions as a main control unit of the image forming apparatus 100, and controls the overall operation of the image forming apparatus 100. The circuit board is a multi-layer printed circuit board.

[0018] The I / O control unit 111 controls communication with external devices such as the host computer 101 via the network 105. The CPU 114 controls operations such as image formation processing by the image forming apparatus 100 by executing computer programs stored in the ROM 112 and storage 115. The RAM 113 provides a working area for the CPU 114 to execute processing, and stores temporary data, etc. The storage 115 stores large volumes of data such as image data and print data temporarily or for a long period of time. For example, the storage 115 stores image data for generating an adjustment image for adjusting image formation conditions. The control programs and operating system executed by the CPU 114 are stored in the ROM 112 and storage 115.

[0019] Operation panel 180 is a user interface equipped with an input interface and an output interface. The input interface is, for example, a key button, a touch panel, etc. The output interface is a display, a speaker, etc. Operation panel 180 accepts instructions and the like by user operation and inputs them to CPU 114. CPU 114 controls the operation of image forming apparatus 100 in response to the instructions. Operation panel 180 also displays the status of image forming apparatus 100 and various setting screens in response to instructions from CPU 114.

[0020] The paper feed unit 140 includes a paper feed device including one or more paper feed stages and a transport unit that transports paper from the paper feed stages to a paper discharge unit. The paper feed unit 140 feeds paper one sheet at a time from the paper feed stages in response to an instruction from the CPU 114.

[0021] Printer engine 150 includes image forming section 152, print position control section 153, image position detection section 154, fixing section 260, and image reading section 290. Image forming section 152 forms an image (toner image) on paper fed by paper feed section 140. Fixing section 260 fixes the image (toner image) on the paper. Image reading section 290 reads the adjustment image printed on the image. Image position detection section 154 detects the image position on the paper based on the result of reading the adjustment image by image reading section 290. Print position control section 153 controls the position of the image formed on the paper based on the image position detected by image position detection section 154.

[0022] 2 is a configuration diagram of image forming apparatus 100. Image forming apparatus 100 has operation panel 180 on top of housing 201. Inside housing 201, controller board 110, storage 115, paper feed unit 140, and printer engine 150 shown in FIG. 1 are provided. Printer engine 150 has built-in mechanisms constituting the engine unit and an engine control unit that controls the processing by each mechanism. The mechanisms constituting the engine unit include an optical processing mechanism for forming an electrostatic latent image, visualizing the electrostatic latent image, and transferring the visual image to paper P, and a fixing processing mechanism for fixing the toner image transferred to paper P.

[0023] The image forming unit 152 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 the colors of the images they form are different. 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 configurations of the M station 221, the C station 222, and the K station 223 will not be described.

[0024] The Y station 220 includes a photosensitive drum 205, a charger 211, an exposure unit 207, and a developing unit 212. The photosensitive drum 205 is a drum-shaped photoconductor having a photosensitive layer on its surface. The charger 211 uniformly charges the surface of the photosensitive drum 205, which rotates around the drum axis. The exposure unit 207 scans the charged surface of the photosensitive drum 205 with a laser beam modulated according to image data.

[0025] The exposure unit 207 includes a laser driver that controls the emission of a semiconductor laser (not shown) in accordance with image data obtained from the CPU 114, a rotary polygon mirror 208, and a reflecting mirror 209. The laser light emitted from the semiconductor laser is deflected in the main scanning direction by the rotary polygon mirror 208, and is guided to the surface of the photosensitive drum 205 by the reflecting mirror 209. An electrostatic latent image is formed on the surface of the photosensitive drum 205 by exposing the surface to light.

[0026] The developing unit 212 develops the electrostatic latent image with toner 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.

[0027] The intermediate transfer belt 252 is wound around rollers such as the inner secondary transfer roller 240, and rotates in a clockwise direction in the figure. The toner images of each color formed on each photosensitive drum 205 are transferred to the rotating intermediate transfer belt 252 so as to be superimposed on each other. The toner images are transferred from the photosensitive drums 205 to the intermediate transfer belt 252 by applying a bias voltage having opposite characteristics to the toner images to the intermediate transfer belt 252. As a result, the intermediate transfer belt 252 carries a full-color toner image. The intermediate transfer belt 252 conveys the carried toner image to a secondary transfer section composed of the inner secondary transfer roller 240 and the outer secondary transfer roller 251 as it rotates.

[0028] The paper feed unit 140 corresponds to a feeding mechanism for the paper P, and includes a storage 210 that stores the paper P, a transport path, transport rollers, etc. The paper feed unit 140 transports the paper P one by one from the storage 210 to the secondary transfer unit. The secondary transfer unit sandwiches and transports the intermediate transfer belt 252 and the paper P between the secondary transfer inner roller 240 and the secondary transfer outer roller 251. At this time, a bias voltage of the opposite polarity to the toner image is applied to the secondary transfer outer roller 251, so that the toner image is transferred from the intermediate transfer belt 252 to the paper P.

[0029] The paper P onto which the toner image has been transferred is transported to the fixing unit 260, which is a fixing processing mechanism. The fixing unit 260 includes a fixing roller 261 having an internal heat source, a pressure roller 262 that is biased toward the fixing roller 261, and a circuit board 300 that controls the fixing processing by the fixing unit 260. The fixing unit 260 fixes the toner image onto the paper P by sandwiching and transporting the paper P 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 paper P between the fixing roller 261 and the pressure roller 262.

[0030] In this manner, an image is printed on the paper P. In the case of double-sided printing, the paper P with an image printed on its first side is transported again to the secondary transfer unit via inversion path 270. By being transported to the secondary transfer unit via inversion path 270, the image-formed side of the paper P is inverted. After the image-formed side of the paper P is inverted, an image is printed on the second side, which is different from the first side, by the secondary transfer unit and fixing unit 260.

[0031] The paper P on which the image is printed passes through an image reading unit 290 provided downstream of the fixing unit 260 in the paper transport direction, and is discharged to the outside of the image forming apparatus 100. When the image formed on the paper P is an image for adjusting the image forming conditions, the image reading unit 290 is used to read the image for adjusting the image forming conditions.

[0032] (Circuit board) In order to perform the image formation process as described above, the image forming apparatus 100 is internally provided with a number of actuators, such as motors and sensors. The actuators are connected to a circuit board on which electrical components for control are mounted. The electrical components mounted on the circuit board are connected by printed wiring. The electrical components control the operation of the actuators. To this end, a number of circuit boards are provided in the image forming apparatus 100 corresponding to the actuators. The circuit boards are controlled by a CPU 114. Note that the controller board 110 on which the CPU 114 is mounted is also an example of a circuit board.

[0033] 3 is a functional block diagram of a circuit board 300 provided in the fixing unit 260. A plurality of motors 309-311 in the fixing unit 260 and a plurality of sensors 312-314 in the fixing unit 260 are electrically connected to the circuit board 300. 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 transports the paper P after the fixing process to a subsequent stage. The sensor 312 detects the paper P transported to the fixing unit 260. The sensor 313 detects the temperature of the fixing roller 261. The sensor 314 detects the paper P after the fixing process.

[0034] The circuit board 300 realizes various functions by using a plurality of electric components. In the example of Fig. 3, the circuit board 300 includes an ACDC converter 302 and a DCDC converter 303 used to generate a desired voltage from a commercial power supply 301. The circuit board 300 further includes a CPU 304, an ASIC (Application Specific Integrated Circuit) 305, and motor drivers 306 to 308 used to control the actuators. A plurality of integrated circuits (ICs) and peripheral electric components corresponding to each IC are mounted on the circuit board 300.

[0035] The ACDC converter 302 generates a power supply voltage (DC) having a predetermined voltage value from the power (AC) supplied from the commercial power supply 301. The DCDC converter 303 generates a power supply voltage having a voltage value different from the power supply voltage generated by the ACDC converter 302 from the power supply voltage supplied from the ACDC converter 302. The power supply voltage generated by the DCDC converter 303 is supplied to the CPU 304, the ASIC 305, etc. The CPU 304 and the ASIC 305 operate by the power supply voltage supplied from the DCDC converter 303. The power supply voltage output from the ACDC converter 302 is also supplied to circuits and motors 309 to 310 that operate at a voltage value different from that of the CPU 304 and the ASIC 305.

[0036] The CPU 304 is connected to the motor drivers 306-308 and the sensors 312-314 via the ASIC 305. The CPU 304 acquires the detection results of the sensors 312-314 and detects the state of the fixing unit 260 based on the detection results. The CPU 304 controls the motor drivers 306-308 via the ASIC 305 in accordance with the detected state of the fixing unit 260, thereby controlling the driving of the motors 309-311.

[0037] Since the circuit board 300 is provided in the fixing unit 260, it controls the operation of the fixing unit 260, but other circuit boards provided in the image forming apparatus 100 also control the operation of corresponding components. Each circuit board in the image forming apparatus 100 is communicatively connected to the controller board 110. Each circuit board can communicate with each other via the controller board 110. Each circuit board appropriately controls the components in the image forming apparatus 100 while sharing information related to the detection results of each sensor and the control state of the motors with each other.

[0038] A large number of electrical components are mounted on the circuit board 300 in FIG. 3. However, there is a possibility that some of the electrical components may become difficult to procure. In order to deal with such a situation, electrical components having the same or similar shapes and specifications as each electrical component are generally investigated in advance as possible substitutes. If a problem occurs in procuring a component, the production of the circuit board can be continued by procuring the replaceable component and mounting it on the circuit board.

[0039] However, certain ICs such as the IC of the DC-DC converter 303 and the IC of the motor driver 306 (or 307, 308) may require specific peripheral components when using the IC. In addition, the number, arrangement, and layout of terminals of the IC, or electrical specifications, may differ, and there may be no substitute IC. In such a case, in order to deal with the situation where it is difficult to procure each IC, there is a method of adding a different electrical component having the same function as the electrical component consisting of each IC and peripheral components to the circuit board and mounting the electrical component exclusively. With this method, it is possible to continue manufacturing the circuit board because the IC that can be procured is mounted according to the availability of mounting parts.

[0040] The circuit board 300 of this embodiment has a configuration that can cope with situations where parts are difficult to procure, and can reduce the area required for mounting electrical parts. A specific circuit diagram and wiring (conductor pattern) of the circuit board will be described below.

[0041] (DCDC converter) 4 is a circuit diagram of the DCDC converter 303. The DCDC converter 303 is exclusively provided with a first electric component 3031 including IC10 and a second electric component 3032 including IC20, which is a replaceable part of IC10. The DCDC converter 303 has an input section 3033 to which a predetermined power supply voltage is supplied from the ACDC converter 302. The DCDC converter 303 converts the power supply voltage supplied by the first electric component 3031 or the second electric component 3032 into a power supply voltage with a DC voltage value different from the DC voltage value of the supplied power supply voltage. Here, the DCDC converter 303 converts a power supply voltage of 12 [V] into a power supply voltage of 3.3 [V] and outputs it.

[0042] In FIG. 4, an input voltage VDD_IN of 12 [V] is supplied from an AC / DC converter 302. When a first electric component 3031 including an IC10 is mounted, the input voltage VDD_IN is input to a second terminal VIN of the IC10. When a second electric component 3032 including an IC20 is mounted, the input voltage VDD_IN is input to a third terminal VIN of the IC20. The first electric component 3031 and the second electric component 3032 can each convert the input voltage VDD_IN into an output voltage VDD_OUT and output it. The function of converting the input voltage VDD_IN into an output voltage VDD_OUT and outputting it is a function common to the IC10 and the IC20.

[0043] The output enable signal is input to the 7th terminal CE of IC10 or the 7th terminal EN of IC20. The output enable signal is transmitted, for example, from the CPU 114 of the controller board 110. The output timing of the output voltage VDD_OUT of IC10 and IC20 is controlled by the output enable signal. IC10 outputs the output voltage VDD_OUT from the 3rd terminal SW. IC20 outputs the output voltage VDD_OUT from the 2nd terminal SW. Both IC10 and IC20 have an output control function of the output voltage VDD_OUT by the output enable signal. In addition, when the input voltage VDD_IN is input, IC10 is supplied with the input voltage VDD_IN to the 7th terminal CE of IC10 so as to enable the output of the output voltage VDD_OUT even if the output enable signal is not input from the CPU 114. Similarly, when the input voltage VDD_IN is input, IC20 is supplied with the input voltage VDD_IN to the 7th terminal EN of IC20 so as to enable the output of the output voltage VDD_OUT even if the output enable signal is not input from the CPU 114. The circuit board 300 includes a resistor R1 and a capacitor C1 as electrical components commonly used by the IC10 and the IC20 to adjust the time until the output voltage VDD_OUT transitions to an output-enabled state.

[0044] IC20 outputs a signal (output status signal) indicating the output status from terminal 4 PG. The output function of the output status signal is unique to IC20, and IC10 does not have a similar function. The output status signal is a signal that indicates whether IC20 is outputting the output voltage VDD_OUT normally. IC20 outputs an output status signal indicating that it is operating normally when the output voltage VDD_OUT output from terminal 2 SW is within the target voltage range, and outputs an output status signal indicating that it is not operating normally when it is outside the target voltage range. For example, IC20 outputs an output status signal of 2.0 [V] when it is operating normally, and outputs an output status signal of 0.8 [V] when it is not operating normally.

[0045] (Unique peripherals) The first electrical component 3031 is composed of the IC 10 and specific peripheral components necessary for the normal operation of the IC 10. The second electrical component 3032 is composed of the IC 20 and specific peripheral components necessary for the normal operation of the IC 20.

[0046] The first electric component 3031 has capacitors C11, C12, C13, C14, C15, and C16 and a resistor R10 as peripheral components of IC10. The second electric component 3032 has capacitors C21, C22, C23, C24, C25, and C26 as peripheral components of IC20. The capacitors C11 to C13 of the first electric component 3031 and the capacitors C21 to C23 of the second electric component 3032 have the same function of removing noise from the input voltage VDD_IN. However, the capacitors C11 to C13 and the capacitors C21 to C23 have different capacitances in order to maintain the operating performance of IC10 and IC20.

[0047] The first electric component component 3031 and the second electric component component 3032 are exclusively mounted on the circuit board 300. However, the circuit board 300 may be configured so that the IC10 and the IC20 are exclusively mounted. For example, the peripheral components of the IC10 and the peripheral components of the IC20 may be mounted in advance, and the IC10 and the IC20 may be exclusively mounted on the circuit board 300 depending on the procurement situation of the electric components. The first electric component component 3031 may be configured so that the IC10 and its peripheral components are configured as one package, and the second electric component component 3032 may be configured so that the IC20 and its peripheral components are configured as one package. In this case, the first electric component component 3031 and the second electric component component 3032 are exclusively mounted on the circuit board 300 as a package.

[0048] (Common peripheral parts) The DC-DC converter 303 is configured to include electrical components that are commonly used by IC10 and IC20. The commonly used electrical components include capacitors C1, C2, C3, C4, C5, and C6, resistors R1, R2, and R3, and peripheral components such as an inductor L1.

[0049] The inductor L1 and the capacitors C2 to C5 are connected to the output line of the output voltage VDD_OUT and have the function of smoothing the output voltage VDD_OUT. The inductor L1 and the capacitors C2 to C5 are large-sized components among the electric components used in the DC-DC converter 303. In the circuit board 300 on which the first electric component 3031 and the second electric component 3032 are exclusively mounted, it is effective in reducing wasted mounting area to treat large components as electric components that can be used in common as much as possible.

[0050] Resistors R2 and R3 are voltage-dividing resistors that divide the output voltage VDD_OUT. The result of dividing the output voltage VDD_OUT by resistors R2 and R3 (divided voltage) is input to the feedback terminals of IC10 and IC20. The feedback terminal of IC10 is terminal 5 FB. The feedback terminal of IC20 is terminal 6 VFB. The feedback terminals monitor whether the output voltage VDD_OUT has reached the target voltage based on the divided voltage. Capacitor C6 removes the AC component of the output voltage VDD_OUT.

[0051] IC10 and IC20 use the divided voltage to determine whether the output voltage VDD_OUT is output at a normal voltage value. If the output voltage VDD_OUT is lower than the target voltage, IC10 and IC20 short-circuit the terminal SW and the terminal VIN internally, and if the output voltage VDD_OUT is higher than the target voltage, they short-circuit the terminal SW and the ground terminal GND internally. For this reason, the divided voltage input to the feedback terminal becomes a reference signal for controlling the output voltage VDD_OUT. The feedback terminal, like the terminal SW, is a necessary terminal for both IC10 and IC20. Resistors R2 and R3 and capacitor C6, which generate the divided voltage input to the feedback terminal for this reason, are electrical components commonly used by IC10 and IC20.

[0052] (Circuit board mounting area) FIG. 5 is an explanatory diagram of the DC-DC converter 303 on the circuit board 300. The circuit board 300 has a four-layer structure. FIG. 5 illustrates the first, third, and fourth layers. The second layer is not shown because it is entirely grounded. The first layer is a component surface (first surface), on which common peripheral components and a first electric component component 3031 are mainly mounted. The third layer is formed with wiring (conductor pattern) of the terminal SW that outputs the output voltage VDD_OUT of the IC10 and a conductor pattern for grounding. The fourth layer is a solder surface (second surface), on which a second electric component component 3032 is mainly mounted. That is, the IC10 can be mounted on one surface (first surface) of the circuit board 300, and the IC20 can be mounted on the other surface (second surface) of the circuit board 300. The mounting area of ​​the IC10 and the mounting area of ​​the IC20 are provided at positions facing each other across the circuit board 300.

[0053] When the first mounting area Z1 where the IC10 is mounted and the second mounting area Z2 where the IC20 is mounted are projected onto a virtual plane parallel to the circuit board 300, the first mounting area Z1 encompasses the second mounting area Z2. When the first mounting area Z1 and the second mounting area Z2 are projected onto a virtual plane parallel to the circuit board 300, a part of the first mounting area Z1 projected onto the virtual plane may overlap with the second mounting area Z2 projected onto the virtual plane. In other words, the first mounting area Z1 has an area that overlaps on the virtual plane when the first mounting area Z1 and the second mounting area Z2 are projected onto a virtual plane parallel to the circuit board 300. This allows the mounting area to be reduced compared to a configuration in which the IC10 and the IC20 are exclusively mounted on the same surface, thereby suppressing an increase in the area of ​​the circuit board 300.

[0054] The inductor L1, the capacitors C1 to C6, and the resistors R1 to R3, which are common peripheral components, are mounted on the first layer, which is the component side. Therefore, the IC10 of the first electric component component 3031 is electrically connected to the inductor L1, the capacitors C1 to C6, and the resistors R1 to R3 by the wiring (conductor pattern) of the first layer. For example, the component side of the circuit board 300 has nine pads as mounting parts for mounting the terminals of the IC10, and a conductor pattern formed to electrically connect the pads and the inductor L1. On the other hand, the IC20 of the second electric component component 3032 is mounted on the fourth layer, which is the solder side, and is electrically connected to the inductor L1 through four vias VIA. For example, the solder side of the circuit board 300 has eight pads as mounting parts for mounting the terminals of the IC20, and a conductor pattern formed to electrically connect the pads and the inductor L1 on the mounting side through four vias VIA. Moreover, these four vias VIA are part of the wiring for connecting IC10 and capacitor C14 included in first electric component 3031. IC10 and capacitor C14 are connected via the third layer. That is, capacitor C14 of first electric component 3031 is mounted on the fourth layer. In this way, in this embodiment, the board area including the vias is reduced.

[0055] The second layer is entirely grounded, but the third layer also has a large ground area. The second layer provides ground for IC10 on the first layer, and the third layer provides ground for IC20 on the fourth layer. In order to suppress noise generated by IC10 and IC20, which are ICs of the DCDC converter 303, and to improve heat dissipation characteristics, large ground areas are formed on the second and third layers. When the first to fourth layers are arranged in a straight line, the vias for connecting to ground are shared by IC10 and IC20. For this reason, the ground of the second layer and the ground of the third layer are connected through vias.

[0056] By using common peripheral components, the board area occupied by the second electric component 3032 is only about 30 to 40% of the fourth layer, which is the solder surface. If the first electric component 3031 and the second electric component 3032 can be mounted without using common peripheral components, the board area would increase because additional peripheral electric components that can be used in common for the second electric component 3032 would be required. In particular, when a large component such as the inductor L1 is mounted on both sides of the circuit board 300 by reflow mounting, there is a high possibility that it will fall or collide, which may reduce the mounting yield. Therefore, it is required to place a large component such as an inductor on one side of the circuit board 300. If the inductors of each unit are arranged on the component surface in consideration of the mounting yield of the circuit board 300, it is estimated that an area of ​​about 1.5 to 2 times the area of ​​the wiring (conductor pattern) in FIG. 5 is required.

[0057] In this embodiment, the inductor L1, the capacitors C1 to C6, the resistors R1 to R3, and the various vias are treated as peripheral components common to the ICs 10 and 20. As a result, even if two units (the first electric component 3031 and the second electric component 3032) can be arranged on both sides of the circuit board 300, it is possible to significantly reduce unused space on the circuit board 300 that would be wasted due to exclusive mounting.

[0058] In the above description, the first mounting area Z1 of the IC10 is larger than the second mounting area Z2 of the IC20, but the circuit board 300 is not limited to the above configuration. For example, when the second mounting area Z2 of the IC20 is larger than the first mounting area Z1 of the IC10, the second mounting area Z2 may be configured to include the first mounting area Z1 when the first mounting area Z1 and the second mounting area Z2 are projected onto a virtual plane parallel to the circuit board 300. Alternatively, when the first mounting area Z1 and the second mounting area Z2 are projected onto a virtual plane parallel to the circuit board 300, a part of the first mounting area Z1 projected onto the virtual plane may overlap with the second mounting area Z2 projected onto the virtual plane. This allows the mounting area to be reduced compared to a configuration in which the IC10 and the IC20 are exclusively mounted on the same surface, and therefore the increase in the area of ​​the circuit board 300 can be suppressed.

[0059] In the above description, the DC-DC converter 303 is used as an example of IC10 and IC20, but even if it is a motor driver IC that controls the driving of a motor, it can be configured so that the IC can be mounted on the component side and the solder side of the circuit board 300. For example, IC10 and IC20 are motor driver ICs included in motor drivers 306, 307, and 308 that drive and control motors 309, 310, and 311. With such a configuration, it is possible to significantly reduce the area of ​​the wiring (conductor pattern) on the circuit board 300.

Claims

1. A circuit board for an image forming apparatus provided with a first integrated circuit or a second integrated circuit, an electrical component provided on a first surface of the circuit board, a first mounting portion provided on the first surface of the circuit board and configured to enable mounting of terminals of the first integrated circuit, a first conductor pattern formed on the first surface and constituting at least a part of a first wiring that connects the first mounting portion and the electrical component, a second mounting portion provided on a second surface opposite to the first surface of the circuit board and configured to enable mounting of terminals of the second integrated circuit, a second conductor pattern formed on the second surface and constituting a part of a second wiring that connects the second mounting portion and the electrical component, a via that penetrates the circuit board and constitutes another part of the second wiring, and characterized by having a circuit board.

2. The circuit board according to claim 1, wherein the via is electrically connected to the first conductor pattern.

3. The circuit board further has an input portion to which a voltage is input, and is characterized by converting a value of the voltage input from the input portion. The circuit board according to claim 1.

4. The circuit board according to claim 1, characterized by controlling a drive source electrically connected to the circuit board.

5. The circuit board according to claim 1, wherein an arrangement of terminals of the first mounting portion corresponding to terminals of the first integrated circuit is different from an arrangement of terminals of the second mounting portion corresponding to terminals of the second integrated circuit.

6. The circuit board according to claim 1, wherein a number of terminals of the first mounting portion corresponding to terminals of the first integrated circuit is different from a number of terminals of the second mounting portion corresponding to terminals of the second integrated circuit.

7. a first region on the first surface where the first integrated circuit is arranged, a second region on the second surface where the second integrated circuit is arranged, and when the first region is projected onto the second surface in a direction perpendicular to the first surface, the projection of the first region at least partially overlaps the second region. The circuit board according to claim 1.

8. An image forming apparatus for forming an image on a sheet, including a circuit board provided with a first integrated circuit or a second integrated circuit, and having conversion means for converting a value of a voltage input to the circuit board, wherein the circuit board is an electrical component provided on a first surface of the circuit board, A first mounting portion provided on the first surface of the circuit board and configured to be able to mount terminals of the first integrated circuit; A first conductor pattern formed on the first surface and constituting at least a part of a first wiring that connects the first mounting portion and the electrical component; A second mounting portion provided on a second surface opposite to the first surface of the circuit board and configured to be able to mount terminals of the second integrated circuit; A second conductor pattern formed on the second surface and constituting a part of a second wiring that connects the second mounting portion and the electrical component; An image forming apparatus, comprising: a via that penetrates the circuit board and constitutes another part of the second wiring.

9. The image forming apparatus according to claim 8, wherein the via is electrically connected to the first conductor pattern.

10.

8. The image forming apparatus according to claim 8, wherein an arrangement of terminals of the first mounting portion corresponding to terminals of the first integrated circuit is different from an arrangement of terminals of the second mounting portion corresponding to terminals of the second integrated circuit.

11.

8. The image forming apparatus according to claim 8, wherein a number of terminals of the first mounting portion corresponding to terminals of the first integrated circuit is different from a number of terminals of the second mounting portion corresponding to terminals of the second integrated circuit.

12. A first region on the first surface where the first integrated circuit is disposed; A second region on the second surface where the second integrated circuit is disposed; and

8. The image forming apparatus according to claim 8, wherein when the first region is projected onto the second surface in a direction perpendicular to the first surface, the projection of the first region at least partially overlaps the second region.

13. An image forming apparatus that forms an image on a sheet, comprising: a rotating body that rotates to form an image; a drive source; and a circuit board provided with a first integrated circuit or a second integrated circuit and configured to control the drive source to rotate the rotating body, wherein the circuit board has an electrical component provided on a first surface of the circuit board; a first mounting portion provided on the first surface of the circuit board and configured to be able to mount terminals of the first integrated circuit; a first conductor pattern formed on the first surface and constituting at least a part of a first wiring that connects the first mounting portion and the electrical component; a second mounting portion provided on a second surface opposite to the first surface of the circuit board and configured to be able to mount terminals of the second integrated circuit; A second conductor pattern formed on the second surface and constituting a part of a second wiring that connects the second mounting portion and the electrical component; An image forming apparatus, comprising: a via that penetrates the circuit board and constitutes another part of the second wiring.

14. The image forming apparatus according to claim 13, wherein the via is electrically connected to the first conductor pattern.

15.

15. The image forming apparatus according to claim 13, wherein an arrangement of terminals of the first mounting portion corresponding to terminals of the first integrated circuit is different from an arrangement of terminals of the second mounting portion corresponding to terminals of the second integrated circuit.

16.

16. The image forming apparatus according to claim 13, wherein a number of terminals of the first mounting portion corresponding to terminals of the first integrated circuit is different from a number of terminals of the second mounting portion corresponding to terminals of the second integrated circuit.

17. A first region where the first integrated circuit is disposed on the first surface; A second region where the second integrated circuit is disposed on the second surface; and

17. The image forming apparatus according to claim 13, wherein when the first region is projected onto the second surface in a direction perpendicular to the first surface, a projection of the first region at least partially overlaps the second region.

Images