Image forming device

Abstract

To provide an image formation apparatus which can suppress the power consumption.SOLUTION: An image formation apparatus (1) comprises: an image formation unit (70); a power source substrate (40) which has a main power source circuit (41) that converts the AC voltage supplied from a commercial AC power source (AC) to a first DC voltage (DV1) and outputs the first DC voltage and a sub power source circuit (42) that converts the AC voltage supplied from the commercial AC power source into a second DC voltage (DV2) and outputs the second DC voltage; a controller substrate (50) which has a main controller (51) that is driven on the basis of the first DC voltage; and an engine substrate (60) which has an engine controller (61) that is driven on the basis of the first DC voltage and controls the image formation unit and a sub controller (62) that is driven on the basis of the second DC voltage and outputs an on / off signal to the main power source circuit of the power source substrate. The engine substrate is arranged so as to be close to the power source substrate with respect to the controller substrate.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus such as a printer. [Background technology]

[0002] The image forming apparatus disclosed in Patent Document 1 includes an image forming unit, a main ASIC, a sub-ASIC, a power supply unit, and a sub-power supply circuit. In this image forming apparatus, the image forming unit and the main ASIC are driven by power output from the power supply unit, and the sub-ASIC is driven by power output from the sub-power supply circuit. The sub-ASIC issues on / off instructions to the power supply unit, detects a detection signal indicating whether the voltage from the power supply unit is equal to or higher than the voltage required to drive the main ASIC, and detects the on / off status of the power switch. Depending on the detection results, the sub-ASIC sends a start signal or a stop signal to the power supply unit and a reset signal or a reset release signal to the main ASIC. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-84699 Summary of the Invention [Problem to be solved by the invention]

[0004] In an image forming device, in addition to a power supply board on which a main power supply circuit and a sub-power supply circuit are arranged, two printed circuit boards may be used, with a main controller arranged on one printed circuit board, a controller board, and an engine controller and a sub-controller arranged on the other printed circuit board, an engine board.

[0005] The main controller has the function of controlling LAN and wireless communication, and connection to external devices via a USB connector. The engine controller has the function of controlling the image forming unit. The sub-controller is powered by power from the sub-power supply circuit and controls the on / off of the main power supply circuit.

[0006] In the above configuration, the engine board has an engine controller that controls many of the electrically powered components that make up the image forming unit, and the instantaneous power consumption of the engine board is greater than that of the controller board. Also, the sub-controller arranged on the engine board is driven by power from the sub-power supply circuit, so power consumption needs to be reduced.

[0007] An object of the present disclosure is to provide an image forming apparatus that can reduce power consumption. [Means for solving the problem]

[0008] In order to solve the above problem, an image forming apparatus according to one embodiment of the present invention includes a power supply board having an image forming unit, a main power supply circuit that converts AC voltage supplied from a commercial power source through a first power supply line into a first DC voltage and outputs the first DC voltage, and a sub-power supply circuit that converts AC voltage supplied from the commercial power source through a second power supply line into a second DC voltage and outputs the second DC voltage, a controller board having a main controller that operates based on the first DC voltage, an engine board that operates based on the first DC voltage and controls the image forming unit, and a sub-controller that operates based on the second DC voltage and outputs an on / off signal to the main power supply circuit of the power supply board, and the engine board is located closer to the power supply board than the controller board.

[0009] According to the above configuration, the engine board is located closer to the power supply board than the controller board. This shortens the wiring from the main power supply circuit mounted on the power supply board to the engine controller mounted on the engine board, thereby reducing power consumption in the wiring. Also, this shortens the wiring from the sub-power supply circuit mounted on the power supply board to the sub-controller mounted on the engine board, thereby reducing power consumption in the wiring.

[0010] In an image forming apparatus according to one aspect of the present invention, the controller board and the engine board may be arranged so that their respective board surfaces are parallel to each other, and the power supply board and the controller board may be arranged on opposite sides of the engine board.

[0011] According to the above configuration, the controller board, engine board, and power supply board are arranged in this order, so that the engine board can be arranged closer to the power supply board than the controller board.

[0012] In an image forming apparatus according to one aspect of the present invention, the controller board and the engine board may be arranged so that their respective board surfaces are included in the same plane, and the power supply board and the controller board may be arranged on opposite sides of the engine board.

[0013] According to the above configuration, the controller board, engine board, and power supply board are arranged in this order, so that the engine board can be arranged closer to the power supply board than the controller board.

[0014] In an image forming apparatus according to one aspect of the present invention, the sub-power supply circuit may include a first capacitor connected to one end of the commercial power supply, a second capacitor connected to the other end of the commercial power supply, and a rectifying and smoothing circuit that rectifies and smoothes the AC voltage applied to the first capacitor and the second capacitor to generate the second DC voltage, and the sub-controller may be driven by the second DC voltage generated by the rectifying and smoothing circuit.

[0015] According to the above configuration, a stable DC voltage can be supplied to the sub-controller by the rectifying and smoothing circuit of the sub-controller.

[0016] In an image forming apparatus according to one aspect of the present invention, the engine board may have a storage element that stores power using the second DC voltage generated by the sub-power supply circuit, and the sub-controller may be driven by the second DC voltage output by the sub-power supply circuit when the commercial power supply is connected to the second power supply line, and may be driven by the voltage output by the storage element when the commercial power supply is not connected to the second power supply line.

[0017] According to the above configuration, even if the commercial power source is not connected to the second power source line, the sub-controller can continue to operate because it is driven by the voltage output from the storage element that stored power when the commercial power source was connected to the second power source line.

[0018] In an image forming apparatus according to one aspect of the present invention, the controller board includes a DC / DC converter that converts the first DC voltage into a third DC voltage and outputs the third DC voltage to the main controller, the DC / DC converter outputs a detection signal indicating whether the third DC voltage is equal to or greater than a voltage required to drive the main controller, and the sub-controller outputs an ON signal to the main power supply circuit when the main power supply circuit transitions from an OFF state to an ON state, receives the detection signal, and if the detection signal indicates that the third DC voltage is equal to or greater than the required voltage, instructs the main controller to start control.

[0019] According to the above configuration, when the main power supply circuit transitions from an off state to an on state, for example, when the power key is turned on, the main power supply circuit turns on and the main controller receives an instruction to start control, so that the main controller can be driven.

[0020] In an image forming apparatus according to one aspect of the present invention, when the main power supply circuit transitions from an on state to an off state, the subcontroller instructs the main controller to stop control, the main controller executes an off preparation process in response to the stop instruction from the subcontroller, and after the off preparation process is completed, instructs the subcontroller to transition the main power supply circuit from an on state to an off state, and the subcontroller outputs an off signal to the main power supply circuit in accordance with the transition instruction.

[0021] According to the above configuration, when the main power supply circuit transitions from an on state to an off state, for example, when the power key is turned off, the main power supply circuit turns off, and the main controller can be stopped.

[0022] In an image forming apparatus according to one aspect of the present invention, the main controller instructs the engine controller to stop control in response to the stop instruction from the sub-controller, the engine controller executes an off-preparation process for the engine controller in response to the stop instruction from the main controller, and after the main controller and the engine controller have completed their own off-preparation processes, the main controller instructs the sub-controller to transition the main power supply circuit from an on state to an off state.

[0023] According to the above configuration, the main controller can be stopped at the same time as the engine controller is stopped.

[0024] In one aspect of the image forming apparatus of the present invention, when the main power supply circuit transitions from an on state to an off state, the sub-controller instructs the main controller to stop control, the main controller instructs the engine controller to stop control in response to the sub-controller's stop instruction, the engine controller executes an off-preparation process for the engine controller in response to the main controller's stop instruction, and after the engine controller's off-preparation process is completed, the sub-controller instructs the sub-controller to transition the main power supply circuit from an on state to an off state.

[0025] According to the above configuration, after the engine controller has completed its turn-off preparation process, the engine controller instructs the sub-controller to transition the main power supply circuit from the on state to the off state, thereby eliminating the need for a signal line to transmit the instruction to transition the main power supply circuit from the main controller on the controller board to the sub-controller on the engine board. [Effects of the Invention]

[0026] According to one embodiment of the present invention, an image forming apparatus capable of reducing power consumption can be provided. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic cross-sectional side view showing an internal configuration of an image forming apparatus. [Figure 2] FIG. 1 is a diagram illustrating an outline of the configuration of an image forming apparatus. [Figure 3] FIG. 2 is a block diagram showing a circuit board configuration of the image forming apparatus. [Figure 4] FIG. 2 is a block diagram showing details of a power supply board and an engine board. [Figure 5] 10 is a sequence chart showing a process at the time of startup of the image forming apparatus. [Figure 6] 10 is a sequence chart showing a process at the time of termination of the image forming apparatus. [Figure 7] FIG. 1 is a diagram illustrating an outline of the configuration of an image forming apparatus. [Figure 8] FIG. 2 is a block diagram showing a circuit board configuration of the image forming apparatus. [Figure 9] 10 is a sequence chart showing a process at the time of termination of the image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0028] An embodiment of the present invention will be described in detail below. For ease of explanation, the same components are denoted by the same reference numerals, and the names and functions of the components are also the same. Therefore, detailed description thereof will not be repeated.

[0029] (Overall configuration of image forming apparatus 1) 1 is a schematic side cross-sectional view showing the internal configuration of image forming apparatus 1. In the following description, when referring to image forming apparatus 1, the terms "upper," "lower," "front," "rear," "right," and "left" respectively correspond to the directions of arrows shown appropriately in each drawing such as FIG.

[0030] As shown in FIG. 1, the image forming apparatus 1 is an LED color printer that forms color images using developers of four colors: yellow (Y), magenta (M), cyan (C), and black (K).

[0031] In the following description, when each component is distinguished by color, the letter "Y" for yellow, "M" for magenta, "C" for cyan, or "K" for black is added to the end of the reference numeral of the component, indicating the color. When each component is not distinguished by color, the letters "Y," "M," "C," and "K" are omitted. In FIG. 1, each component is distinguished by color, and the letters "Y," "M," "C," and "K" are added to the end of the reference numeral of the component.

[0032] However, the image forming apparatus 1 is not limited to an LED color printer, and may be, for example, a laser color printer, a facsimile machine, or a so-called multifunction machine having a printer function and a reading function.

[0033] As shown in Fig. 1, the image forming apparatus 1 includes a housing 2. A paper feed tray 4 on which sheets 3 are stacked is provided at the bottom of the housing 2. A pickup roller 5 is provided above the front end of the paper feed tray 4. As the pickup roller 5 rotates, the topmost sheet 3 stacked in the paper feed tray 4 is sent to a separation roller 71.

[0034] The sheets 3 are separated one by one between the separation roller 71 and a separation pad (not shown) and conveyed toward the conveying roller 72. Thereafter, the position of the leading edge of the sheet 3 is regulated by the registration roller 6, which is in a stopped state of rotation, and then the sheet 3 is conveyed onto the belt unit 11 through the conveying path.

[0035] Also provided on the conveyance path are a paper feed sensor 9, a pre-registration sensor 8, and a post-registration sensor 7, each capable of detecting the passage of a sheet 3. The paper feed sensor 9 is disposed downstream of the pickup roller 5 and separation roller 71 in the conveyance direction of the sheet 3. The pre-registration sensor 8 is disposed downstream of the paper feed sensor 9 and conveyance roller 72 and upstream of the registration rollers 6 in the conveyance direction of the sheet 3. The post-registration sensor 7 is disposed downstream of the registration rollers 6 and upstream of the photosensitive drum 28Y in the conveyance direction of the sheet 3.

[0036] The belt unit 11 is configured such that a circular belt 13 is stretched between a belt support roller 12A disposed at the front side and a belt drive roller 12B disposed at the rear side. Inside the belt 13, transfer rollers 14Y to 14K are provided at positions facing the photosensitive drums 28Y to 28K corresponding to the four process sections 19Y to 19K, respectively, with the belt 13 interposed therebetween.

[0037] When the belt unit 11 is installed in the housing 2, the belt drive roller 12B is connected to a process motor (not shown) provided in the housing 2 via a gear mechanism (not shown). The belt drive roller 12B is driven to rotate by the power of the process motor, causing the belt 13 to circulate in the clockwise direction as shown in the drawing, thereby transporting the sheet 3 on the top surface of the belt 13 backward.

[0038] Above the belt unit 11, exposure units 17Y-17K corresponding to the four process units 19Y-19K are arranged in a line in the front-to-rear direction. The exposure units 17Y-17K are supported on the underside of the cover 2A, and each has an LED head 18Y-18K with a plurality of LEDs arranged in a row at its bottom end. The light emission of the exposure unit 17 is controlled based on the image data to be formed, and the LED head 18 irradiates the surface of the photosensitive drum 28 with light line by line, i.e., the photosensitive drum 28 is scanned line by line to perform exposure.

[0039] Each of the process units 19Y-19K includes a cartridge frame 21Y-21K, a developing cartridge 22Y-22K detachably mounted in the cartridge frame 21Y-21K, a photosensitive drum 28Y-28K, and a charger 29Y-29K. When the cover 2A is opened, the exposure unit 17 moves upward together with the cover 2A, and the process unit 19 can be individually detached from the housing 2.

[0040] The developing cartridges 22Y to 22K each include a developer containing chamber 23Y to 23K that contains a developer of a corresponding color, and each include a supply roller 24Y to 24K, a developing roller 25Y to 25K, and a layer thickness regulating blade 26Y to 26K below it.

[0041] The developer discharged from the developer storage chamber 23 is supplied onto the developing roller 25 by the rotation of the supply roller 24, and is positively triboelectrically charged between the supply roller 24 and the developing roller 25. Furthermore, as the developing roller 25 rotates, the developer supplied onto the developing roller 25 enters between the layer thickness regulating blade 26 and the developing roller 25, where it is further sufficiently triboelectrically charged and carried on the developing roller 25 as a thin layer of a constant thickness.

[0042] A photosensitive drum 28, the surface of which is covered with, for example, a positively chargeable photosensitive layer, and a charger 29 are provided below the cartridge frame 21. During image formation, the photosensitive drum 28 is rotated, and the surface of the photosensitive drum 28 is uniformly positively charged by the charger 29. The positively charged portion is then exposed by scanning of the exposure unit 17, and an electrostatic latent image is formed on the surface of the photosensitive drum 28.

[0043] Next, the positively charged developer carried on the developing roller 25 is supplied to the electrostatic latent image on the surface of the photosensitive drum 28, thereby making the electrostatic latent image on the photosensitive drum 28 visible. Thereafter, the developer image carried on the surface of the photosensitive drum 28 is sequentially transferred onto the sheet 3 by a negative transfer voltage applied to the transfer roller 14 while the sheet 3 passes through the nip position between the photosensitive drum 28 and the transfer roller 14. The sheet 3 onto which the developer image has been transferred is then transported to a fixing unit 31 equipped with a heater 31A.

[0044] The fixing unit 31 includes a heating roller 33 having a heater 31A, a pressure roller 32 that presses the sheet 3 toward the heating roller 33, and a third thermistor 36, and thermally fixes the developer image transferred onto the sheet 3 to the paper surface. After that, the sheet 3 that has been thermally fixed by the fixing unit 31 is transported upward and discharged onto the top surface of the cover 2A. A third thermistor 36 is located near the heating roller 33. The third thermistor 36 detects the temperature of the heating roller 33.

[0045] The image forming apparatus 1 is provided with a fan 10 for ventilating the inside of the image forming apparatus 1 and a duct 10A with a ventilation hole, above the paper feed tray 4. Within the image forming apparatus 1, heat is generated from the fixing unit 31, the process unit 19, etc. during image formation. In order to prevent the temperature inside the image forming apparatus 1 from rising due to the generated heat, the fan 10 has the function of lowering the temperature inside the image forming apparatus 1 by letting outside air flow into the image forming apparatus 1.

[0046] (Circuit board arrangement of image forming device 1) Fig. 2 is a diagram showing the general configuration of the image forming apparatus 1. Fig. 2(A) is a diagram showing the general configuration of the interior of the image forming apparatus 1 as viewed from above. Fig. 2(B) is a diagram showing the general configuration of the interior of the image forming apparatus 1 as viewed from the left side.

[0047] 2(A) is a diagram showing an outline of the internal configuration of the image forming apparatus 1 as seen from above. The image forming apparatus 1 includes a power supply board 40, a controller board 50, an engine board 60, and an image forming unit 70 inside a housing 2. Details of each board will be described later.

[0048] Furthermore, the image forming apparatus 1 includes a resin frame JF, a drive system member KB such as a clutch and gears, two sheet metal frames BF, and a fan 10. The photosensitive drums 28K, 28C, 28M, and 28Y that constitute the image forming unit 70 are axially supported between the two sheet metal frames BF, and are rotationally driven by the drive system member KB.

[0049] 2A, in the image forming apparatus 1, the controller board 50 and the engine board 60 are arranged so that the board surface 501 of the controller board 50 and the board surface 601 of the engine board 60 are parallel to each other. In this case, the controller board 50 and the engine board 60 are connected by a board-to-board connector. The power supply board 40 and the controller board 50 are arranged on opposite sides of the engine board 60.

[0050] As shown in FIG. 2B, in the image forming device 1, the controller board 50 and the engine board 60 overlap each other, but the lower end 602 of the engine board 60 is closer to the power supply board 40 than the lower end 502 of the controller board 50.

[0051] As shown in Figures 2(A) and 2(B), in the image forming device 1, the power supply board 40 is arranged so that the board surface 401 of the power supply board 40, the board surface 501 of the controller board 50, and the board surface 601 of the engine board 60 are perpendicular to each other.

[0052] According to the above, the engine board 60 is disposed closer to the power supply board 40 than the controller board 50. As a result, the engine board 60, which has higher instantaneous power consumption than the controller board 50, is closer to the power supply board 40, and the wiring between the boards is shortened, thereby reducing power consumption due to the wiring and allowing sufficient power to be supplied from the power supply board 40 to the engine board 60. Furthermore, when the sub-controller 62 of the engine board 60 is driven by power from the sub-power supply circuit 42 of the power supply board 40, the wiring between the boards is shortened, and power consumption due to the wiring can be reduced.

[0053] (Board configuration of image forming apparatus 1) 3 is a block diagram showing the board configuration of the image forming apparatus 1. As shown in FIG.

[0054] <Power supply board 40> The power supply board 40 has a main power supply circuit 41 and a sub-power supply circuit 42 .

[0055] The main power supply circuit 41 converts an AC voltage supplied from an external commercial AC power supply AC through the first power supply line PL1 into a first DC voltage DV1 and outputs the first DC voltage DV1. The commercial AC power supply AC is, for example, a 100V AC power supply.

[0056] The sub-power supply circuit 42 converts an AC voltage supplied from an external commercial AC power supply AC through the second power supply line PL2 into a second DC voltage DV2 and outputs the second DC voltage DV2. The first power supply line PL1 and the second power supply line PL2 are, for example, power cords.

[0057] <Controller board 50> The controller board 50 has a main controller 51 , a third DC / DC converter 52 , a fourth DC / DC converter 53 , a USB interface 54 , and a LAN interface 55 .

[0058] The main controller 51 is driven by a third DC voltage DV3 output by the fourth DC / DC converter 53. The third DC / DC converter 52 converts the first DC voltage DV1 output by the main power supply circuit 41 into a first intermediate DC voltage MDV1 and outputs the first intermediate DC voltage MDV1 to the fourth DC / DC converter 53. The fourth DC / DC converter 53 converts the first intermediate DC voltage MDV1 output by the third DC / DC converter 52 into a third DC voltage DV3 and outputs the third DC voltage DV3 to the main controller 51.

[0059] The third DC / DC converter 52 and the fourth DC / DC converter 53 correspond to DC / DC converters that convert the first DC voltage DV1 output by the main power supply circuit 41 into a third DC voltage DV3 and output the third DC voltage DV3 to the main controller 51.

[0060] The USB interface 54 controls USB connections with external devices, and the LAN interface 55 controls communications via a LAN.

[0061] <Engine board 60> The engine board 60 has an engine controller 61 , a sub-controller 62 , a first DC / DC converter 63 , a second DC / DC converter 64 , and a power storage element circuit 65 .

[0062] The engine controller 61 is driven by a fourth DC voltage DV4 output by the second DC / DC converter 64, and controls the image forming unit 70. The sub-controller 62 is driven by a second DC voltage DV2 output by the sub-power supply circuit 42, and outputs an on / off signal to the main power supply circuit 41 of the power supply board 40. The on / off signal is a signal that indicates on or off.

[0063] The first DC / DC converter 63 converts the first DC voltage DV1 output by the main power supply circuit 41 into a second intermediate DC voltage MDV2 and outputs the second intermediate DC voltage MDV2 to the second DC / DC converter 64. The second DC / DC converter 64 converts the second intermediate DC voltage MDV2 output by the first DC / DC converter 52 into a fourth DC voltage DV4 of 3 V and outputs the fourth DC voltage DV4 to the engine controller 61.

[0064] The power storage element circuit 65 stores power using the second DC voltage DV2 generated by the sub-power supply circuit .

[0065] <Image forming unit 70> The image forming unit 70 is an electrophotographic mechanism that forms a color image on a sheet 3 (see FIG. 1) such as print paper that is conveyed one sheet at a time along a conveyance path. The image forming unit 70 has a scanner unit that includes a light source that outputs laser light, a polygon mirror, and a polygon motor, and a conveyance unit that includes conveyance rollers that convey the sheet, and is equipped with a motor that generates driving force for rotating the polygon mirror and for the conveyance rollers, etc.

[0066] <Operation panel 80> The operation panel 80 has a power key 81 for turning the power of the image forming apparatus 1 on and off.

[0067] FIG. 4 is a block diagram showing the power supply board 40 and the engine board 60 in detail.

[0068] <Main power supply circuit 41> The main power supply circuit 41 is connected to a first power supply line PL1 and receives an AC voltage from a commercial AC power supply AC via the first power supply line PL1. The first power supply line PL1 includes a pair of power feed lines PL11 and PL12. The main power supply circuit 41 includes a rectifying and smoothing circuit 411, a transformer 412, and a control IC 413.

[0069] The rectifying and smoothing circuit 411 has a pair of input terminals 4111 and 4112. One of the input terminals 4111 is connected to one of the power supply lines PL11. The other of the input terminals 4112 is connected to the other of the power supply lines PL12.

[0070] The rectifying and smoothing circuit 411 includes, for example, a transformer having both terminals of a primary coil connected to a pair of input terminals 4111 and 4112, a bridge circuit formed by connecting four diodes in a bridge configuration, with a pair of input terminals connected to both terminals of the secondary coil of the transformer, and a capacitor having a pair of electrodes connected to each of a pair of output terminals of the bridge circuit.

[0071] With this configuration, the AC voltage input from a pair of power supply lines PL11, PL12 of the first power line PL1 to a pair of input terminals 4111, 4112 of the rectifying smoothing circuit 411 is converted into a DC voltage of a predetermined voltage by the rectifying smoothing circuit 411 and output from the rectifying smoothing circuit 411.

[0072] The transformer 412 transforms the DC voltage output from the rectifying and smoothing circuit 411 into a first DC voltage DV1 of 6 V or 24 V in accordance with the control of the control IC 413, and outputs the first DC voltage DV1 to the engine board 60.

[0073] The control IC 413 controls the transformer 412 to output the first DC voltage DV1 from the transformer 412 and also stops the output of the first DC voltage DV1. The control IC 413 starts / stops control of the transformer 412 in response to an on signal / off signal received from the sub-controller 62, thereby turning on / off the output of the first DC voltage DV1 to the engine board 60. The control IC 413 also receives a 6V / 24V switching signal from the main controller 51 and controls the transformer 412 to switch the output of the first DC voltage DV1 to the engine board 60 in response to the received 6V / 24V switching signal.

[0074] <Sub-power supply circuit 42> The sub-power supply circuit 42 is connected to the second power supply line PL2 and receives AC voltage from the commercial AC power supply AC through the second power supply line PL2. The sub-power supply circuit 42 has a first capacitor 421, a second capacitor 422, and a rectifying and smoothing circuit 423.

[0075] The first capacitor 421 has a first electrode EP1 and a second electrode EP2. The first electrode EP1 is connected to one power supply line PL21 of the second power supply line PL2 via a connection line CL1. The power supply line PL21 is connected to one end of a commercial AC power supply AC. The second electrode EP2 is connected to an input terminal 4231 of the rectifying and smoothing circuit 423.

[0076] The second capacitor 422 has a third electrode EP3 and a fourth electrode EP4. The third electrode EP3 is connected to the other power supply line PL22 of the second power supply line PL2 via a connection line CL2. The power supply line PL22 is connected to the other end of the commercial AC power supply AC. The fourth electrode EP4 is connected to an input terminal 4232 of the rectifying and smoothing circuit 423.

[0077] The rectifying and smoothing circuit 423 has a pair of input terminals 4231 and 4232. The second electrode EP2 of the first capacitor 421 is connected to one input terminal 4231. The fourth electrode EP4 of the second capacitor 422 is connected to the other input terminal 4232.

[0078] The AC power supplied from the commercial AC power supply AC through the second power supply line PL2 has its voltage amplitude suppressed to a small value by the impedance of the first capacitor 421 and the second capacitor 422, and is input to a pair of input terminals 4231, 4232 of the rectifying and smoothing circuit 423.

[0079] The rectifying and smoothing circuit 423 has a configuration similar to that of the rectifying and smoothing circuit 411 of the main power supply circuit 41. The rectifying and smoothing circuit 423 rectifies and smoothes the AC voltage that is applied to the first capacitor 421 and the second capacitor 422 and input to a pair of input terminals 4231, 4232, to generate a second DC voltage DV2 that is a predetermined sub-power supply voltage. The rectifying and smoothing circuit 423 outputs the second DC voltage DV2 to the sub-controller 62 via the power storage element circuit 65.

[0080] <Engine Controller 61> The engine controller 61 is driven when it is in an ON state, in which the fourth DC voltage DV4 is supplied from the second DC / DC converter 64. In the ON state, the engine controller 61 receives a control start signal or a control stop signal from the main controller 51.

[0081] When the engine controller 61 receives the start signal, it performs initialization such as rewriting the registers built into the engine controller 61 to initial values, and starts executing the program that controls the image forming unit 70. When the engine controller 61 receives the stop signal, it stops executing the program that controls the image forming unit 70.

[0082] <Subcontroller 62> The sub-controller 62 is driven by a second DC voltage DV2 of 3 V that is generated by the rectifying and smoothing circuit 423 of the sub-power supply circuit 42 and input via the storage element circuit 65. Because the sub-controller 62 is driven by the second DC voltage DV2 from the sub-power supply circuit 42, it can be driven even when the main power supply circuit 41 is off.

[0083] When the sub-controller 62 detects that the power key 81 (see FIG. 3) on the operation panel 80 has been operated to on / off, it sends an on / off signal to the control IC 413 of the main power supply circuit 41. When the sub-controller 62 receives a main power supply circuit stop signal from the main controller 51, it sends an off signal to the control IC 413 of the main power supply circuit 41.

[0084] <Storage element circuit 65> The storage element circuit 65 is connected between the sub-power supply circuit 42 and the sub-controller 62. The storage element circuit 65 is a circuit in which a backup capacitor 651, a resistor 652, and a diode 653 are connected in series.

[0085] The backup capacitor 651 has a fifth electrode EP5 and a sixth electrode EP6. The fifth electrode EP5 is connected to the ground GR. A series circuit of a resistor 652 and a diode 653 is connected to the sixth electrode EP6. Specifically, the sixth electrode EP6 is connected to one end 6521 of the resistor 652. The diode 653 has an anode connected to the output terminal OUT3 of the first DC / DC converter 63 and a cathode connected to the other end 6522 of the resistor 652.

[0086] <First DC / DC converter 63> The first DC / DC converter 63 has a switch 631 and a conversion circuit 632. The switch 631 switches between a closed circuit and an open circuit between the main power supply circuit 41 and the conversion circuit 632 in response to an on signal or an off signal from the main controller 51. When the switch 631 is closed, the conversion circuit 632 converts the first DC voltage DV1 output from the main power supply circuit 41 into a second intermediate DC voltage MDV2 and outputs the second intermediate DC voltage MDV2 to the second DC / DC converter 64.

[0087] When a DC voltage is output from the output terminal OUT3 of the first DC / DC converter 63, the voltage is applied between the fifth electrode EP5 and the sixth electrode EP6 of the backup capacitor 651, and the backup capacitor 651 is charged.

[0088] When the commercial AC power supply AC is connected to the second power supply line PL2 of the power supply board 40, the sub-controller 62 is driven by the second DC voltage DV2 output from the sub-power supply circuit 42. When the commercial AC power supply AC is not connected to the second power supply line PL2 of the power supply board 40, the sub-controller 62 is driven by the DC voltage stored in and output from the backup capacitor 651 of the storage element circuit 65.

[0089] <Startup sequence> FIG. 5 is a sequence chart showing the process performed when the image forming apparatus 1 is started up.

[0090] When main power supply circuit 41 transitions from the off state to the on state, for example, when power key 81 on operation panel 80 is turned on, sub-power supply circuit 42 of power supply board 40 is turned on (step S101).

[0091] When the sub-power supply circuit 42 is turned on, the sub-controller 62 is activated from the off state to the on state, and outputs an on signal to the main power supply circuit 41 (step S102).

[0092] When the main power supply circuit 41 receives the ON signal from the sub-controller 62, it outputs the first DC voltage DV1 of 6 V to the third DC / DC converter 52 (step S103).

[0093] On the controller board 50, the third DC / DC converter 52 is turned on by receiving the first DC voltage DV1 of 6V from the main power supply circuit 41 (step S104), the fourth DC / DC converter 53 is turned on by the first intermediate DC voltage MDV1 (step S105), and the main controller 51 is turned on by the third DC voltage DV3 (step S106).

[0094] When the fourth DC / DC converter 53 is turned on, it transmits a PGOOD signal to the sub-controller 62, which is a detection signal indicating that the third DC voltage DV3 output to the main controller 51 is equal to or greater than the voltage required to drive the main controller 51 (step S107).

[0095] When the sub-controller 62 receives the PGOOD signal from the fourth DC / DC converter 53, the PGOOD signal indicates that the third DC voltage DV3 to be output to the main controller 51 is equal to or greater than the required voltage, and so the sub-controller 62 sends a control start signal to the main controller 51 (step S108).

[0096] When the main controller 51 receives a control start signal from the sub-controller 62 in the ON state, it initializes itself, including initializing registers, and transmits an ON signal to the first DC / DC converter 63 (step S109).

[0097] In the engine board 60, when the first DC / DC converter 63 receives an on signal from the main controller 51, it is turned on (step S110), the second DC / DC converter 64 is turned on by the second intermediate DC voltage MDV2 (step S111), and the engine controller 61 is turned on by the fourth DC voltage DV4 (step S112).

[0098] When the second DC / DC converter 64 is turned on, it transmits a PGOOD signal to the main controller 51, which is a detection signal indicating that the fourth DC voltage DV4 output to the engine controller 61 is equal to or greater than the voltage required to drive the engine controller 61 (step S113).

[0099] When the main controller 51 receives the PGOOD signal from the second DC / DC converter 64, the PGOOD signal indicates that the fourth DC voltage DV4 to be output to the engine controller 61 is equal to or greater than the required voltage, and so the main controller 51 transmits a control start signal to the engine controller 61 (step S114). When the engine controller 61 receives the control start signal from the main controller 51 in the on state, it initializes itself (step S115).

[0100] The main controller 51 further transmits a 24V switching signal to the main power supply circuit 41 (step S116). Upon receiving the 24V switching signal from the main controller 51, the main power supply circuit 41 outputs a first DC voltage DV1 of 24V (step S117). This completes the startup process of the image forming apparatus 1.

[0101] <End sequence> FIG. 6 is a sequence chart showing the process of the image forming apparatus 1 when it is shut down.

[0102] When the main power supply circuit 41 transitions from an ON state to an OFF state, for example, when the power key 81 of the operation panel 80 is turned OFF, the sub-controller 62 transmits a control stop signal to the main controller (step S201).

[0103] When the main controller 51 receives the control stop signal from the sub-controller 62, it executes a power-off preparation process, and after the power-off preparation process is completed, it transmits a control stop signal to the engine controller 61 (step S202).

[0104] When the engine controller 61 receives the control stop signal from the main controller 51, the engine controller 61 executes and completes the off preparation process of the engine controller 61 (step S203).

[0105] Thereafter, the main controller 51 transmits an OFF signal to the first DC / DC converter 63 (step S204).

[0106] In the engine board 60, when the first DC / DC converter 63 receives an off signal from the main controller 51, it turns off (step S205), the third DC / DC converter 64 turns off (step S206), and the engine controller 61 turns off (step S207).

[0107] After the main controller 51 has completed its own off preparation process and the off preparation process of the engine controller 61, it transmits a stop signal to the sub-controller 62 to instruct the main power supply circuit 41 to transition from the on state to the off state (step S208). Upon receiving the stop signal from the main controller 51, the sub-controller 62 transmits an off signal to the main power supply circuit 41 (step S209).

[0108] The main power supply circuit 41 is turned off when it receives an off signal from the sub-controller 62 (step S210). When the main power supply circuit 41 is turned off, on the controller board 50, the third DC / DC converter 52 is turned off (step S211), the fourth DC / DC converter 53 is turned off (step S212), and the main controller 51 is turned off (step S213). This completes the shutdown process of the image forming apparatus 1.

[0109] [Variation 1] An image forming apparatus 1A will be described as Modification 1. In particular, differences between image forming apparatus 1 and image forming apparatus 1A will be described.

[0110] Fig. 7 is a diagram showing the general configuration of image forming apparatus 1A. Fig. 7(A) is a diagram showing the general configuration of the interior of image forming apparatus 1A as viewed from above. Fig. 7(B) is a diagram showing the general configuration of the interior of image forming apparatus 1A as viewed from the left side.

[0111] 7(A), in image forming apparatus 1A, engine board 60 is hidden by controller board 50 when viewed from a direction parallel to board surfaces 601, 501. In other words, controller board 50 and engine board 60 are arranged so that board surface 501 of controller board 50 and board surface 601 of engine board 60 are included in the same plane. In this case, controller board 50 and engine board 60 are connected by a normal harness.

[0112] As shown in FIG. 7(B), the power supply board 40 and the controller board 50 are arranged on opposite sides of the engine board 60.

[0113] As shown in Figures 7(A) and 7(B), in the image forming apparatus 1A, the power supply board 40 is arranged so that the board surface 401 of the power supply board 40, the board surface 501 of the controller board 50, and the board surface 601 of the engine board 60 are perpendicular to each other.

[0114] According to the above, the engine board 60 is disposed closer to the power supply board 40 than the controller board 50 is.

[0115] [Variation 2] Image forming apparatus 1B will be described as Modification 2. In particular, differences between image forming apparatus 1 and image forming apparatus 1B will be described.

[0116] 3, in the image forming apparatus 1, the main controller 51 of the controller board 50 transmits a stop signal for the main power supply circuit 41 to the sub-controller 62 of the engine board 60. Therefore, a signal line for transmitting the stop signal for the main power supply circuit 41 is arranged between the controller board 50 and the engine board 60.

[0117] 8 is a block diagram showing the board configuration of the image forming apparatus 1B. As shown in FIG. 8, in the image forming apparatus 1B, the engine controller 61 in the engine board 60 sends a stop signal for the main power supply circuit 41 to the sub-controller 62.

[0118] As described above, in image forming apparatus 1B, main controller 51 does not transmit a stop signal for main power supply circuit 41 to sub-controller 62, so there is no need for a signal line for transmitting a stop signal for main power supply circuit 41 between controller board 50 and engine board 60. Therefore, the number of signal lines between controller board 50 and engine board 60 can be reduced.

[0119] FIG. 9 is a sequence chart showing the process at the time of termination of the image forming apparatus 1B.

[0120] When the main power supply circuit 41 transitions from an ON state to an OFF state, for example, when the power key 81 on the operation panel 80 is turned OFF, the sub-controller 62 transmits a control stop signal to the main controller 51 (step S301).

[0121] When the main controller 51 receives the control stop signal from the sub-controller 62, it executes a power-off preparation process, and after the power-off preparation process is completed, it transmits a control stop signal to the engine controller 61 (step S302).

[0122] When the engine controller 61 receives the control stop signal from the main controller 51, the engine controller 61 executes and completes the engine controller 61 off preparation process (step S303).

[0123] Thereafter, the engine controller 61 transmits a stop signal to the sub-controller 62 to instruct the main power supply circuit 41 to transition from the on state to the off state (step S304). Upon receiving the stop signal from the engine controller 61, the sub-controller 62 transmits an off signal to the main power supply circuit 41 (step S305).

[0124] When the main power supply circuit 41 receives the off signal from the sub-controller 62, it is turned off (step S306).

[0125] When the main power supply circuit 41 is turned off, the first DC / DC converter 63 on the engine board 60 is turned off (step S307), the second DC / DC converter 64 is turned off (step S308), and the engine controller 61 is turned off (step S309).

[0126] When the main power supply circuit 41 is turned off, the third DC / DC converter 52 is turned off on the controller board 50 (step S310), the fourth DC / DC converter 53 is turned off (step S311), and the main controller 51 is turned off (step S312). This completes the shutdown process of the image forming apparatus 1B.

[0127] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0128] 1, 1A, 1B Image forming device 40 Power supply board 41 Main power circuit 42 Sub-power circuit 50 Controller board 51 Main Controller 52 Third DC / DC converter 53 4th DC / DC converter 60 Engine board 61 Engine Controller 62 Sub-controller 65 Storage element circuit 70 Image forming unit 411, 423 Rectifier smoothing circuit 421 First Capacitor 422 Second Capacitor PL1 First power line PL2 Second power line DV1 First DC voltage DV2 Second DC voltage DV3 Third DC voltage

Claims

1. an image forming unit; a power supply substrate including: a main power supply circuit that converts an AC voltage supplied from a commercial power supply through a first power supply line into a first DC voltage and outputs the first DC voltage; and a sub-power supply circuit that converts an AC voltage supplied from the commercial power supply through a second power supply line into a second DC voltage and outputs the second DC voltage; a controller board having a main controller that is driven based on the first DC voltage; an engine board including an engine controller that is driven based on the first DC voltage and controls the image forming unit, and a sub-controller that is driven based on the second DC voltage and outputs an on / off signal to a main power supply circuit of the power supply board; Equipped with The engine board is disposed closer to the power supply board than the controller board. An image forming apparatus characterized by:

2. the controller board and the engine board are arranged so that their respective board surfaces are parallel to each other; The power supply board and the controller board are disposed on opposite sides of the engine board.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. the controller board and the engine board are arranged so that their respective board surfaces are included in the same plane; The power supply board and the controller board are disposed on opposite sides of the engine board.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. The sub-power supply circuit includes: a first capacitor connected to one end of the commercial power supply; a second capacitor connected to the other end of the commercial power supply; a rectifying and smoothing circuit that rectifies and smoothes the AC voltage applied to the first capacitor and the second capacitor to generate the second DC voltage, the sub-controller is driven by the second DC voltage generated by the rectifying and smoothing circuit; 4. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. the engine board has a power storage element that stores power using the second DC voltage generated by the sub-power supply circuit, The sub-controller The power supply circuit is driven by the second DC voltage output from the sub-power supply circuit when the commercial power supply is connected to the second power supply line, The power supply is driven by a voltage output from the power storage element in a state where the commercial power supply is not connected to the second power supply line.

5. The image forming apparatus according to claim 4.

6. The controller board a DC / DC converter that converts the first DC voltage into a third DC voltage and outputs the third DC voltage to the main controller; The DC / DC converter outputting a detection signal indicating whether the third DC voltage is equal to or greater than a voltage required to drive the main controller; The sub-controller When the main power supply circuit transitions from an off state to an on state, an on signal is output to the main power supply circuit; receiving the detection signal, and if the detection signal indicates that the third DC voltage is equal to or greater than the required voltage, instructing the main controller to start control; 6. The image forming apparatus according to claim 4, wherein the image forming apparatus is a recording medium.

7. The sub-controller When the main power supply circuit transitions from an on state to an off state, an instruction to stop control is given to the main controller; The main controller executes a power-off preparation process in response to the instruction to stop from the sub-controller, and after the power-off preparation process is completed, instructs the sub-controller to transition the main power supply circuit from an on state to an off state; the sub-controller outputs an OFF signal to the main power supply circuit in accordance with the instruction to transition; 6. The image forming apparatus according to claim 4, wherein the image forming apparatus is a recording medium.

8. The main controller instructing the engine controller to stop control in response to the stop instruction from the sub-controller; The engine controller executes a turn-off preparation process for the engine controller in response to the stop instruction from the main controller; The main controller After the completion of the respective off preparation processes of the sub-controller and the engine controller, the sub-controller issues an instruction to transition the main power supply circuit from an on state to an off state.

8. The image forming apparatus according to claim 7,

9. The sub-controller When the main power supply circuit transitions from an on state to an off state, an instruction to stop control is given to the main controller; The main controller instructing the engine controller to stop control in response to the stop instruction from the sub-controller; The engine controller executes an engine controller off preparation process in response to the stop instruction from the main controller, and after the engine controller off preparation process is completed, issues an instruction to the sub-controller to transition the main power supply circuit from an on state to an off state; 6. The image forming apparatus according to claim 4, wherein the image forming apparatus is a recording medium.

Images