Image-forming device

Abstract

Provided is an image-forming device in which an ASIC can be easily replaced. This image-forming device comprises a low-voltage power supply substrate (140), a sub-substrate (120), and a main substrate (110). The low-voltage power supply substrate (140) converts AC voltage into DC voltage at a first voltage. The sub-substrate (120) has a first connector (C1) to which a terminal of a harness for connecting the low-voltage power supply substrate (140) is connected, and a second connector (C2) to which a terminal of a harness for connecting a main motor (160) is connected. The main substrate (110) is detachably housed in a main body housing. The main substrate (110) electrically connects the sub-substrate (120) and an ASIC (111) that controls the main motor (160). The DC voltage at the first voltage is supplied to the main motor (160) from the low-voltage power supply substrate (140) via the sub-substrate (120) without passing through the main substrate (110). The ASIC (111) transmits a control signal to the main motor (160) via the main connector (CM) and the sub-substrate (120).

Description

Image forming device

[0001] The present invention relates to an image forming apparatus having a detachable main board.

[0002] Conventionally, there has been known an image forming apparatus equipped with a detachable main board (see Patent Document 1). The main board is provided with an ASIC (main control circuit) that controls the image forming apparatus. The main board is connected to multiple electrical components, such as an image forming unit and an operation panel, and is configured to transmit control signals, power, and the like from the ASIC to the multiple electrical components.

[0003] Japanese Patent Application Laid-Open No. 2003-241924

[0004] In conventional image forming devices, the main board with the ASIC is connected to multiple electrical components, requiring numerous wiring connections. This necessitates the need to reconnect and reconnect numerous wiring connections when replacing the main board, making replacing the ASIC time-consuming. Therefore, the present invention aims to provide an image forming device that allows for easy ASIC replacement.

[0005] In order to solve the above problems, the image forming apparatus according to the present invention includes a main body housing, a photosensitive drum, a low-voltage power supply board, a sub-board, and a main board. The photosensitive drum is rotatable about a rotation axis extending in a first direction. The main motor provides driving force to the photosensitive drum. The low-voltage power supply board is provided with an AC / DC converter that converts AC voltage supplied from a commercial power source into DC voltage of a first voltage. The sub-board has a first connector to which a terminal of a harness connecting the low-voltage power supply board is connected, and a second connector to which a terminal of a harness connecting the main motor is connected. The main board is detachably housed in the main body housing. The main board electrically connects the sub-board to an ASIC that controls the main motor. The main motor receives DC voltage of the first voltage from the low-voltage power supply board via the sub-board, without passing through the main board. The ASIC sends a control signal to the main motor via the main connector and the sub-board.

[0006] The main motor is supplied with the first DC voltage without passing through the main board. This eliminates the need to connect the main board and the main motor with a harness or the like, reducing the amount of wiring on the main board and allowing the main board to be made more compact. As a result, the amount of work required to plug and unplug wiring when replacing the main board can be reduced, making it easier to replace the ASIC. Furthermore, because the first DC voltage is not supplied to the main board, an unnecessarily high voltage is not supplied to the main board.

[0007] The sub-board may further include a main motor drive circuit that outputs drive power for driving the main motor. The main motor drive circuit may be supplied with the first DC voltage from the low-voltage power supply board without passing through the main board. The main board may transmit a control signal for controlling the main motor to the main motor drive circuit via the main connector.

[0008] Because the main motor drive circuit is located on the sub-board, wiring connecting the main board and the main motor is not required, compared to a configuration in which the main motor drive circuit is located on the main board, and the labor required to plug and unplug wiring when replacing the main board can be reduced. This makes it easy to replace the ASIC. Furthermore, because the first DC voltage is not supplied to the main board, an unnecessarily high voltage is not supplied to the main board.

[0009] The sub-board may further include a DC / DC converter that converts the first voltage into a second voltage that is lower than the first voltage, and the main board may be supplied with the second DC voltage via the main connector.

[0010] Since the DC / DC converter that converts the first voltage into a second voltage that is lower than the first voltage is located on the sub-board, the first voltage is not supplied to the main board, and an unnecessarily high voltage is not supplied to the main board. Furthermore, by supplying voltage from the sub-board to the main board and transmitting signals from the main board to the sub-board via a single main connector, the number of connectors and harnesses connected to the main board can be reduced, and the ASIC can be easily replaced.

[0011] The image forming apparatus may further include a developing roller that supplies toner to the photosensitive drum, a charger that charges the photosensitive drum, and a transfer roller that transfers the toner image from the photosensitive drum to a sheet. The ASIC may be configured to control voltages applied to the developing roller, the charger, and the transfer roller via the main connector and the sub-board.

[0012] The image forming apparatus may further include a high-voltage power supply board on which a charging voltage application circuit that applies a charging voltage to the charger, a development voltage application circuit that applies a development voltage to the development roller, and a transfer voltage application circuit that applies a transfer voltage to the transfer roller are arranged, the high-voltage power supply board being connected to a sub-board via a harness. The sub-board may have a third connector to which a terminal of the harness that connects the high-voltage power supply board is connected. The high-voltage power supply board may receive a first DC voltage from the low-voltage power supply board via the sub-board, without passing through the main board. The ASIC may be configured to send control signals to the charging voltage application circuit, development voltage application circuit, and transfer voltage application circuit via the main connector and the sub-board.

[0013] Since the high-voltage power supply board receives the first DC voltage from the low-voltage power supply board via the sub-board, not via the main board, the first voltage is not supplied to the main board, and an unnecessarily high voltage is not supplied to the main board. In addition, the wiring connected to the main board can be reduced, making it easy to replace the ASIC.

[0014] The image forming apparatus may further include an exposure unit that exposes the photosensitive drum, the exposure unit having a light source device that emits laser light, a polygon mirror that deflects the laser light, and a polygon motor that rotates the polygon mirror. The sub-board may further include a fourth connector to which a terminal of a harness that connects the polygon motor is connected. The polygon motor may receive a first DC voltage from the low-voltage power supply board via the sub-board, not via the main board. The ASIC may be configured to send a control signal to the polygon motor via the main connector and the sub-board.

[0015] In the polygon motor, the first voltage is supplied to the main board from the low-voltage power supply board via the sub-board, bypassing the main board, so the first voltage is not supplied to the main board, and an unnecessarily high voltage is not supplied to the main board. In addition, the wiring connected to the main board can be reduced, making it easy to replace the ASIC.

[0016] The sub-board may also have a fifth connector that is directly connected to the main connector without using a harness.

[0017] The sub-board has a fifth connector that is directly connected to the main connector without a harness, which reduces the number of harnesses required. In addition, the fifth connector supports the main connector, allowing the main board to be supported by the sub-board.

[0018] Alternatively, the main board may face the same direction as the sub-board, and the main connector may be connected to the fifth connector in a direction along the surface of the sub-board.

[0019] The main body housing may have an attachment / detachment opening that opens in the vertical direction and in a second direction perpendicular to the first direction, and the main board may be removable by being pulled out in the second direction from the attachment / detachment opening.

[0020] The sub-board may also have a notch recessed in the second direction, and the main board may be disposed in the notch when attached inside the main body housing.

[0021] When the main board is attached inside the main body housing, the main board is disposed in the notch, so that the main board and the sub-board can be disposed compactly.

[0022] The area of ​​the main board may be smaller than the area of ​​the sub-board.

[0023] Since the area of ​​the main board is smaller than the area of ​​the sub-board, the main board can be easily replaced.

[0024] The main board may also have a USB connection terminal to which a USB connector can be connected, and the USB connection terminal may be exposed on the outer surface of the main body housing when the main board is attached to the main body housing.

[0025] The USB connection terminal is exposed on the outer surface of the main body housing, making it easy to connect a USB connector.

[0026] The main board may also have a LAN connection terminal to which a LAN connector can be connected, and when the main board is attached to the main body housing, the LAN connection terminal may be exposed on the outer surface of the main body housing.

[0027] Since the LAN connection terminal is exposed on the outer surface of the main body housing, it is easy to connect a LAN connector.

[0028] The main board may further include an authentication IC for authenticating devices that communicate with the ASIC.

[0029] The main board has an authentication IC for authenticating devices that communicate with the ASIC, which helps prevent hacking and the intrusion of malicious programs. In addition, because the authentication IC can be replaced along with the ASIC when the main board is replaced, the authentication IC can always be updated to match the security performance required when replacing the ASIC, and even if the product has a long lifespan, the performance and security of the ASIC can be maintained by simply replacing the main board.

[0030] According to the present invention, it is possible to provide an image forming apparatus in which the ASIC can be easily replaced.

[0031] 1 is a cross-sectional view showing an image forming apparatus according to an embodiment; FIG. 2 is a perspective view showing a main board, a sub-board, a low-voltage power supply board, a high-voltage power supply board, a main motor, etc.; FIG. 3 is a block diagram showing electrical connections and control signals for the main board, the sub-board, the low-voltage power supply board, the high-voltage power supply board, the main motor, etc.; FIG. 4 is a view of the image forming apparatus as seen from above, showing the positions of the main board, the sub-board, the low-voltage power supply board, the high-voltage power supply board, the main motor, etc.; FIG. 5 is a view of the image forming apparatus as seen from the left, showing the positional relationship between the main board, the sub-board, the low-voltage power supply board, the high-voltage power supply board, the main motor, etc.; and FIG. 6 is a view of the image forming apparatus as seen from the left, showing the positional relationship between the main board, the sub-board, the low-voltage power supply board, the high-voltage power supply board, the main motor, etc.

[0032] An embodiment of the present disclosure will be described in detail with reference to the accompanying drawings as appropriate. As shown in FIG. 1, an image forming apparatus 1 is a monochrome printer. In the following description, the front side (right side in FIG. 1) as viewed from a user using the image forming apparatus 1 will be referred to as the "front" and the rear side (left side in FIG. 1) as the "rear." The up-down direction is the vertical direction. The front-to-rear direction is perpendicular to the up-down direction. Furthermore, the left side (front side of the paper in FIG. 1) as viewed from the user will be referred to as the "left," and the right side (rear side of the paper in FIG. 1) will be referred to as the "left."

[0033] The image forming apparatus 1 includes a main body housing 10 , a front cover 20 , a sheet supply unit 30 , an image forming unit 40 , discharge rollers 81 , and an operation panel 180 .

[0034] The main body housing 10 is a housing that houses the sheet supply unit 30, the image forming unit 40, etc. The front cover 20 opens and closes a front opening 11 of the main body housing 10. The front opening 11 is formed in the front surface of the main body housing 10.

[0035] The operation panel 180 is disposed on the top surface 10A of the main body housing 10. The operation panel 180 can display various messages and can also be used to input commands to the image forming apparatus 1. The operation panel 180 is disposed near the front of the main body housing 10.

[0036] The sheet supply unit 30 supplies sheets S to the image forming unit 40. The sheet supply unit 30 is located at the bottom inside the main body housing 10. The sheet supply unit 30 includes a sheet tray 31 and a sheet supply mechanism 32. The sheet tray 31 stores sheets S to be supplied to the image forming unit 40. The sheet tray 31 is detachable from the main body housing 10. When the sheet tray 31 is to be removed, the sheet tray 31 is pulled forward from the main body housing 10. When the sheet tray 31 is attached to the main body housing 10, it is located below the image forming unit 40.

[0037] The sheet supply mechanism 32 includes a pickup roller 33 as an example of a conveying roller, a separation roller 34, a separation pad 35, a first roller 36, and a registration roller 37. The pickup roller 33 feeds the sheets S stored in the sheet tray 31 toward the photosensitive drum 61. The separation roller 34 and the separation pad 35 separate the sheets S fed by the pickup roller 33 into single sheets. The first roller 36 and the registration roller 37 convey the sheets S toward the image forming unit 40.

[0038] The image forming section 40 forms an image on the sheet S. The image forming section 40 includes an exposure unit 50, a process unit 60, and a fixing unit 70.

[0039] The exposure unit 50 is located at the top of the main body housing 10. The exposure unit 50 has an optical device 51, a polygon mirror 52, and a polygon motor 53. The optical device 51 emits laser light. The polygon mirror 52 deflects the laser light emitted from the optical device 51. The polygon motor 53 rotates the polygon mirror 52. As shown by the imaginary lines, the exposure unit 50 emits a light beam from the optical device 51, which is deflected by the polygon mirror 52 and then exposes the surface of a photosensitive drum 61 of the image forming unit 40.

[0040] The process unit 60 is located between the exposure unit 50 and the sheet tray 31 inside the main body casing 10. The process unit 60 includes a drum unit 60A and a developing unit 60B that is detachable from the drum unit 60A.

[0041] The process unit 60 is detachable from the main body housing 10 through the front opening 11 when the front cover 20 is open. To remove the process unit 60, the process unit 60 is pulled forward from the main body housing 10 with the front cover 20 open. The development unit 60B is detachable from the drum unit 60A when the process unit 60 is removed from the main body housing 10. The drum unit 60A has a photosensitive drum 61, a charger 62, and a transfer roller 63.

[0042] The photosensitive drum 61 is rotatable about a rotation axis 61X extending in a first direction. A toner image is formed on the surface of the photosensitive drum 61. The charger 62 uniformly and positively charges the photosensitive drum 61. The transfer roller 63 transfers the toner image from the photosensitive drum 61 to the sheet S.

[0043] In the following description, the direction in which the rotation axis 61X of the photosensitive drum 61 extends is referred to as the "first direction." Furthermore, the direction perpendicular to the up-down direction and the first direction is referred to as the "second direction." Furthermore, the arrow directions in the drawings point to one side of each direction. Furthermore, the direction opposite to one side is referred to as the other side. In this embodiment, the first direction is the left-right direction, with one side of the first direction referring to the left side and the other side of the second direction referring to the right side. The second direction is the front-rear direction. In this embodiment, one side of the second direction is the rear side and the other side of the second direction is the front side.

[0044] The developing unit 60B has a developing roller 64, a supply roller 65, a layer thickness regulating blade 66, an agitator 67, and a toner storage section 68. The toner storage section 68 stores toner. The agitator 67 agitates the toner in the toner storage section 68. The agitator 67 also supplies toner to the supply roller 65. The supply roller 65 supplies toner to the developing roller 64. The layer thickness regulating blade 66 contacts the surface of the developing roller 64 to regulate the thickness of the toner on the developing roller 64 to a constant thickness. The developing roller 64 supplies toner to the photosensitive drum 61.

[0045] The fixing unit 70 is located behind the process unit 60 inside the main body housing 10. The fixing unit 70 includes a heating unit 71 and a pressure roller 72. The heating unit 71 heats the sheet S. The pressure roller 72 is pressed against the heating unit 71.

[0046] In the image forming section 40, the exposure unit 50 emits a light beam onto the surface of the charged photosensitive drum 61. As a result, an electrostatic latent image based on image data is formed on the photosensitive drum 61. The development roller 64 supplies toner to the surface of the exposed photosensitive drum 61. As a result, a toner image is formed on the photosensitive drum 61.

[0047] The photosensitive drum 61 and the transfer roller 63 transport the sheet S supplied from the sheet supply unit 30. As a result, the toner image formed on the photosensitive drum 61 is transferred onto the sheet S. The heating unit 71 and the pressure roller 72 transport the sheet S onto which the toner image has been transferred. As a result, the toner image transferred onto the sheet S is fixed onto the sheet S.

[0048] The discharge rollers 81 are located above the fixing unit 70. The discharge rollers 81 discharge the sheet S, on which an image has been formed by the image forming section 40, onto the discharge tray 13. The discharge tray 13 is formed on the top surface 10A of the main body housing 10.

[0049] As shown in Figures 2 and 3, the image forming apparatus 1 includes a main board 110, a sub-board 120, a wireless board 130, a low-voltage power supply board 140, a high-voltage power supply board 150, a main motor 160, a first harness H1, a second harness H2, a third harness H3, a fourth harness H4, a fifth harness H5, and a sixth harness H6.

[0050] The main board 110 and the sub-board 120 are directly connected without a harness, and the sub-board 120 and the wireless board 130 are directly connected without a harness.

[0051] The sub-board 120 and the low-voltage power supply board 140 are connected via a first harness H1. The sub-board 120 and the main motor 160 are connected via a second harness H2. The sub-board 120 and the high-voltage power supply board 150 are connected via a third harness H3. The sub-board 120 and the exposure unit 50 are connected via a fourth harness H4 and a fifth harness H5. The sub-board 120 and the operation panel 180 are connected via a sixth harness H6.

[0052] The type of harness is arbitrary, and the harness may be an FFC (flexible flat cable).

[0053] 4, the main body housing 10 has a first region RE1 and a second region RE2. The first region RE1 is located outside the photosensitive drum 61 in the first direction and is on one side of the photosensitive drum 61 in the first direction. The second region RE2 is located outside the photosensitive drum 61 in the first direction and is on the other side of the photosensitive drum 61 in the first direction.

[0054] The main board 110, the sub-board 120, the wireless board 130, and the main motor 160 are all arranged in the first region RE1. The low-voltage power supply board 140 and the high-voltage power supply board 150 are arranged in the second region RE2.

[0055] The first harness H1 extends from the first region RE1 to the second region RE2 along the first direction. Specifically, the first harness H1 passes on one side of the rotation axis 61X of the photosensitive drum 61 in the second direction and extends from the first region RE1 to the second region RE2.

[0056] The main board 110 and the sub-board 120 are located on one side in the second direction of the rotation axis 61X of the photosensitive drum 61. The main board 110 and the sub-board 120 are located on one side in the second direction of the photosensitive drum 61.

[0057] 6 , when viewed from the first direction, the low-voltage power supply board 140 overlaps with the main board 110 and the sub-board 120. When viewed from the first direction, the high-voltage power supply board 150 does not overlap with the main board 110, the sub-board 120, or the low-voltage power supply board 140.

[0058] The sub-substrate 120 has a notch 120K recessed in the second direction. Specifically, the sub-substrate 120 has a first portion 120A, a second portion 120B, and a third portion 120C. The first portion 120A has a rectangular shape that is long in the vertical direction. The second portion 120B extends from an upper portion of the first portion 120A to one side in the second direction and has a rectangular shape that is long in the second direction. The third portion 120C extends from a lower portion of the first portion 120A to one side in the second direction and has a rectangular shape that is long in the second direction. The notch 120K is formed between the first portion 120A, the second portion 120B, and the third portion 120C.

[0059] When the main board 110 is installed inside the main housing 10, it is disposed in the notch 120K of the sub-board 120. In other words, when the main board 110 is installed inside the main housing 10, it is disposed between the second portion 120B and the third portion 120C of the sub-board 120.

[0060] In this embodiment, the area of ​​the main board 110 is smaller than the area of ​​the sub-board 120 .

[0061] 3, the wireless board 130 has a wireless communication module 131. The wireless communication module 131 is capable of performing wireless communication for wirelessly connecting the image forming apparatus 1 and a wireless device. The wireless communication is, for example, wireless communication conforming to the wireless LAN standard, such as Wi-Fi (registered trademark) communication.

[0062] The wireless communication module 131 may also perform short-distance wireless communication. The short-distance wireless communication referred to here is called NFC (Near Field Communication), and particularly refers to a short-distance wireless communication standard with a communication distance of approximately 10 cm or less, such as ISO / IEC 18092 and ISO / IEC 21481, including FeliCa (registered trademark) and Mifare (registered trademark). Bluetooth (registered trademark) may also be considered a type of short-distance wireless communication.

[0063] The low-voltage power supply board 140 has an AC / DC converter 141. The AC / DC converter 141 is a converter that converts AC voltage supplied from a commercial power source into DC voltage of a first voltage. The first voltage is, for example, 24 V. The low-voltage power supply board 140 is covered by a box-shaped metal enclosure (not shown). The low-voltage power supply board 140 is housed in the main body housing 10 in a detachable manner.

[0064] The high-voltage power supply board 150 is detachably housed in the main body housing 10. The high-voltage power supply board 150 is connected to the sub-board 120 via a harness. The high-voltage power supply board 150 has a circuit that generates a high voltage by boosting the first voltage supplied from the low-voltage power supply board 140. The high-voltage power supply board 150 has a charging voltage application circuit 151, a developing voltage application circuit 152, and a transfer voltage application circuit 153.

[0065] The charging voltage application circuit 151 is a circuit that applies a positive charging voltage to the charger 62. The charging voltage is, for example, 5 kV to 8 kV. The developing voltage application circuit 152 is a circuit that applies a positive developing voltage to the developing roller 64. The developing voltage is, for example, 300 V to 500 V. The transfer voltage application circuit 153 is a circuit that applies a transfer voltage to the transfer roller 63. The transfer voltage application circuit 153 controls the transfer voltage so that the current flowing through the transfer roller 63 becomes a predetermined current value. The transfer voltage is, for example, about minus several thousand volts.

[0066] The main motor 160 applies a driving force to the pickup roller 33, the separation roller 34, the first roller 36, the registration roller 37, the photosensitive drum 61, the developing roller 64, the supply roller 65, the agitator 67, the pressure roller 72, and the discharge roller 81. The pickup roller 33, the separation roller 34, the first roller 36, the registration roller 37, the photosensitive drum 61, the pressure roller 72, and the discharge roller 81 receive the driving force from the main motor 160 and transport the sheet S.

[0067] As shown in FIG. 3, the main board 110 has an ASIC 111, a sub-converter 112, an authentication IC 113, a ROM 114, a RAM 115, a non-volatile memory 116, a USB connection terminal 118, a LAN connection terminal 119, and a main connector CM.

[0068] The ROM 114 stores a control program, setting data, and the like for controlling the image forming apparatus 1. The RAM 115 and the non-volatile memory 116 are used as a working area from which the control program is read and as a storage area for temporarily storing image data included in a print job.

[0069] The ASIC 111 is a semiconductor integrated circuit for executing print control of the image forming apparatus 1. The ASIC 111 executes print control by performing arithmetic processing based on programs and data stored in the ROM 114, the RAM 115, and the non-volatile memory 116. In this embodiment, the ASIC 111 controls the operation panel 180, the exposure unit 50, and the main motor 160.

[0070] The sub-converter 112 is a converter that converts a second DC voltage into a third DC voltage that is lower than the second voltage. The second voltage is, for example, 5 V or 3.3 V. The third voltage is, for example, 1.1 V.

[0071] The authentication IC 113 is an IC for authenticating the security of devices, networks, etc. that communicate with the ASIC 111. If a long period of time has passed since the image forming apparatus 1 began to be used, the authentication IC 113 can be replaced with a new one at the same time as the main board 110 is replaced, thereby updating the security of communication with devices connected to the ASIC 111.

[0072] The USB connection terminal 118 and the LAN connection terminal 119 are disposed at one end of the main board 110 in the second direction. When the main board 110 is attached to the main body housing 10, the USB connection terminal 118 and the LAN connection terminal 119 are exposed on the outer surface of the main body housing 10 from one side (rear side) of the main body housing 10 in the second direction.

[0073] The USB connection terminal 118 is a terminal to which a USB connector of an external device such as a PC can be connected. When the USB connector of the external device is connected to the USB connection terminal 118, the ASIC 111 can send and receive data to and from the external device.

[0074] A LAN connector can be connected to the LAN connection terminal 119. When a LAN connector is connected to the LAN connection terminal 119, the ASIC 111 can transmit and receive data to and from external devices.

[0075] The main connector CM is a connector that is connected to the sub-board 120. The main connector CM faces the other side (forward) in the second direction. The main connector CM is attached to and detached from a fifth connector C5 of the sub-board 120, which will be described later, in the second direction. The main connector CM electrically connects the ASIC 111 and the sub-board 120.

[0076] As shown in FIG. 5 , the main board 110 is detachably housed in the main body housing 10. The main board 110 is an easily replaceable board. Specifically, the main body housing 10 has a second opening 12 and a rear cover 12A. The second opening 12 is a removable opening formed in the first region RE1 and opening in a second direction. The second opening 12 is formed on the rear surface of the main body housing 10. The second opening 12 allows the main board 110 to be pulled out in the second direction for removal. The rear cover 12A is rotatable between a closed position (see FIG. 4 ) that covers the second opening 12 and an open position (see FIG. 5 ) that opens the second opening 12. As shown in FIG. 5 , when the rear cover 12A is in the closed position, the main board 110 can be attached and detached through the second opening 12.

[0077] As shown in FIG. 3 , the sub-board 120 does not have a main control circuit such as an ASIC or CPU. The sub-board 120 electrically connects the main board 110 to multiple electrical components. The sub-board 120 has a DC / DC converter 121, a main motor drive circuit 122, and a polygon motor drive circuit 123. The sub-board 120 also has a first connector C1, a second connector C2, a third connector C3, a fourth connector C4, a fifth connector C5, a sixth connector C6, a seventh connector C7, and an eighth connector C8. Note that because FIG. 3 is a block diagram showing the electrical connections of each board, the positions of the connectors may differ from those in FIGS. 2 and 4 .

[0078] The DC / DC converter 121 is a converter that converts a first voltage DC to a second voltage lower than the first voltage. For example, the first voltage is 24 V. The second voltage is 5 V or 3.3 V. The second voltage DC is supplied to the main board 110 via the main connector CM.

[0079] The main motor drive circuit 122 is a circuit that outputs drive power for driving the main motor 160. Specifically, the main motor drive circuit 122 is supplied with a first DC voltage from the low-voltage power supply board 140. The main motor drive circuit 122 outputs drive power to the main motor 160 based on a control signal sent from the ASIC 111.

[0080] The polygon motor drive circuit 123 is a circuit that drives the polygon motor 53. Specifically, the polygon motor drive circuit 123 is supplied with a first DC voltage from the low-voltage power supply board 140. The polygon motor drive circuit 123 outputs drive power to the polygon motor 53 based on a control signal sent from the ASIC 111.

[0081] The first connector C1 is a connector to which terminals of a harness that connects the low-voltage power supply board 140 to the sub-board 120 are connected. Terminals of a first harness H1, which is an example of a harness, are connected to the first connector C1.

[0082] The second connector C2 is a connector to which terminals of a harness that connects the main motor 160 to the sub-board 120 are connected. Terminals of a second harness H2, which is an example of a harness, are connected to the second connector C2.

[0083] The third connector C3 is a connector to which a terminal of a harness that connects the high-voltage power supply board 150 to the sub-board 120 is connected. A terminal of a third harness H3, which is an example of a harness, is connected to the third connector C3.

[0084] The fourth connector C4 is a connector to which a terminal of a harness that connects the polygon motor 53 of the exposure unit 50 to the sub-board 120 is connected. A terminal of a fourth harness H4, which is an example of a harness, is connected to the fourth connector C4.

[0085] The fifth connector C5 is a connector for connecting the main board 110 to the sub-board 120. The fifth connector C5 is connected to the main connector CM of the main board 110. As shown in Fig. 2, the main board 110 is directly connected to the fifth connector C5 without using a harness.

[0086] In this embodiment, the main board 110 is disposed parallel to the sub-board 120 and faces the same direction. The main connector CM is connected to the fifth connector C5 in a direction along the surface of the sub-board 120. That is, the fifth connector C5 faces the main connector CM in the second direction, and the two connectors face each other. That is, the fifth connector C5 faces one side of the second direction, for example, backward.

[0087] The fifth connector C5 and the main connector CM are board-to-board connectors for connecting the boards together. At least one of the fifth connector C5 and the main connector CM may be a floating connector designed to absorb positional errors by moving relative to the main board 110 and the sub-board 120.

[0088] The sixth connector C6 is a connector for connecting the optical device 51 of the exposure unit 50 to the sub-board 120. A terminal of the fifth harness H5 is connected to the sixth connector C6.

[0089] The seventh connector C7 is a connector for connecting the operation panel 180 to the sub-board 120. A terminal of the sixth harness H6 is connected to the seventh connector C7.

[0090] The eighth connector C8 is a connector for connecting the wireless communication module 131. The eighth connector C8 is connected to the wireless connector CW of the wireless board 130. That is, the wireless board 130 is directly connected to the eighth connector C8 without using a harness. The eighth connector C8 is a board-to-board connector for connecting boards to each other. In this embodiment, the eighth connector C8 is disposed on the second portion 120B of the sub-board 120.

[0091] Here, the transmission path of the power supplied from the low-voltage power supply board 140 and the transmission path of the control signal sent from the ASIC 111 will be described.

[0092] The main motor drive circuit 122 is supplied with power from the low-voltage power supply board 140. More specifically, the main motor drive circuit 122 is supplied with a first DC voltage from the AC / DC converter 141 via the first connector C1. That is, the main motor 160 is supplied with the first DC voltage from the low-voltage power supply board 140 via the sub-board 120, without passing through the main board 110.

[0093] The main motor drive circuit 122 is supplied with the first DC voltage from the low-voltage power supply board 140 without passing through the main board 110. The main board 110 then transmits a control signal for controlling the main motor 160 to the main motor drive circuit 122 via the main connector CM. In this way, the main motor drive circuit 122 converts the first DC voltage into a drive voltage for the main motor 160 based on the control signal sent from the ASIC 111 and outputs the converted voltage.

[0094] The ASIC 111 transmits a control signal to the main motor 160 via the main connector CM and the sub-board 120. The ASIC 111 also receives a signal from the main motor 160 via the sub-board 120 and the main connector CM.

[0095] The polygon motor drive circuit 123 is supplied with power from the low-voltage power supply board 140. More specifically, the polygon motor drive circuit 123 is supplied with a first DC voltage from the AC / DC converter 141 via the first connector C1. That is, the polygon motor 53 is supplied with the first DC voltage from the low-voltage power supply board 140 via the sub-board 120, without passing through the main board 110.

[0096] The polygon motor drive circuit 123 is supplied with the first DC voltage from the low-voltage power supply board 140 without passing through the main board 110. The main board 110 then transmits a control signal for controlling the polygon motor 53 to the polygon motor drive circuit 123 via the main connector CM. In this way, the polygon motor drive circuit 123 converts the first DC voltage into a drive voltage for the polygon motor 53 and outputs it based on the control signal sent from the ASIC 111.

[0097] The ASIC 111 transmits a control signal to the polygon motor 53 via the main connector CM and the sub-board 120. The ASIC 111 also receives a signal from the polygon motor 53 via the sub-board 120 and the main connector CM.

[0098] The high-voltage power supply board 150 receives the first DC voltage from the low-voltage power supply board 140 via the sub-board 120, without passing through the main board 110. The ASIC 111 controls the voltages applied to the developing roller 64, the charger 62, and the transfer roller 63 via the main connector CM and the sub-board 120.

[0099] The charging voltage application circuit 151 receives power from the low-voltage power supply board 140 via the sub-board 120, without passing through the main board 110. The ASIC 111 transmits a control signal to the charging voltage application circuit 151 via the main connector CM and the sub-board 120. That is, the charging voltage application circuit 151 outputs a charging voltage to the charger 62 based on the control signal sent from the ASIC 111 via the sub-board 120. The ASIC 111 also receives a signal from the charging voltage application circuit 151 via the sub-board 120.

[0100] The developing voltage application circuit 152 receives power from the low-voltage power supply board 140 via the sub-board 120, without passing through the main board 110. The ASIC 111 transmits a control signal to the developing voltage application circuit 152 via the main connector CM and the sub-board 120. That is, the developing voltage application circuit 152 outputs a developing voltage to the developing roller 64 based on the control signal sent from the ASIC 111 via the sub-board 120. The ASIC 111 also receives a signal from the developing voltage application circuit 152 via the sub-board 120.

[0101] The transfer voltage application circuit 153 receives power from the low-voltage power supply board 140 via the sub-board 120, without passing through the main board 110. The ASIC 111 sends a control signal to the transfer voltage application circuit 153 via the main connector CM and the sub-board 120. That is, the transfer voltage application circuit 153 outputs a transfer voltage to the transfer roller 63 based on the control signal sent from the ASIC 111 via the sub-board 120. The ASIC 111 also receives a signal from the transfer voltage application circuit 153 via the sub-board 120.

[0102] The DC / DC converter 121 is supplied with power from the low-voltage power supply board 140. More specifically, the DC / DC converter 121 is supplied with a direct current voltage of the first voltage from the AC / DC converter 141 via the fourth connector C4 and the first connector C1. The DC / DC converter 121 converts the direct current of the first voltage into a second voltage and outputs it to the main board 110. The amount of power supplied from the low-voltage power supply board 140 to the DC / DC converter 121 is adjusted based on a control signal sent from the ASIC 111.

[0103] The ASIC 111 communicates with the wireless communication module 131 via the sub-board 120 .

[0104] The ASIC 111 transmits a control signal to the optical device 51 via the sub-board 120 to control the emission of laser light from the optical device 51. The ASIC 111 also receives a signal from the optical device 51 via the sub-board 120.

[0105] The ASIC 111 can receive commands input to the operation panel 180 via the sub-board 120 and can also send messages to the operation panel 180 .

[0106] Next, a method for attaching and detaching the main board 110 will be described.

[0107] 6, the main board 110 and the sub-board 120 are detachably housed in the main body housing 10. Here, the main body housing 10 has a metal plate 10B, a first rail RA1, and a second rail RA2.

[0108] The metal plate 10B is a metal plate and extends in a direction perpendicular to the first direction. The first rail RA1 extends in the second direction. The first rail RA1 is arranged along the lower end of the second portion 120B of the sub-board 120. The second rail RA2 extends in the second direction. The second rail RA2 is arranged along the upper end of the third portion 120C of the sub-board 120. The first rail RA1 and the second rail RA2 can guide the main board 110 so that it can slide in the second direction (front-to-back direction).

[0109] The sub-board 120 is fixed to the main body housing 10. Specifically, the sub-board 120 is fixed to the metal plate 10B with four screws N. When removing the sub-board 120, the four screws N are removed to remove the sub-board 120 from the metal plate 10B.

[0110] The main board 110 is fixed to the main housing 10. The upper end of the main board 110 is held by a first rail RA1, and the lower end is held by a second rail RA2, so that the main board 110 cannot move in the vertical direction. Furthermore, the main connector CM is connected to the first connector C1 of the sub-board 120, so that the main board 110 cannot move in the second direction.

[0111] When removing the main board 110 from the main body housing 10, the rear cover 12A is moved from the closed position shown in Fig. 4 to the open position shown in Fig. 5. When the rear cover 12A is moved to the open position as shown in Fig. 5, the second opening 12 is opened.

[0112] With the second opening 12 open, the user pulls the main board 110 to one side in the second direction, for example, backward. As shown in Figure 7, pulling the main board 110 backward releases the connection between the main connector CM of the main board 110 and the first connector C1 of the sub-board 120, allowing the main board 110 to move in the second direction along the first rail RA1 and the second rail RA2. This allows the main board 110 to be pulled out to one side in the second direction, for example, backward.

[0113] As shown in Fig. 5, when attaching the main board 110 to the main housing 10, the rear cover 12A is opened and the main board 110 is inserted into the second opening 12. Then, as shown in Fig. 7, the upper and lower ends of the main board 110 are inserted into the first rail RA1 and the second rail RA2, and the main board 110 is pushed forward along the first rail RA1 and the second rail RA2. This brings the main connector CM of the main board 110 into contact with the first connector C1 of the sub-board 120, and by further pushing the main board forward, the main connector CM is connected to the first connector C1.

[0114] 6, when the main connector CM is connected to the first connector C1, the main board 110 is fixed to the main housing 10. In this way, the first connector C1 serves as a reference for positioning the main board 110 in the front-to-rear direction. After the main board 110 is attached to the main housing 10, the rear cover 12A is closed (see FIG. 5).

[0115] As described above, the present embodiment can achieve the following advantages. In the image forming apparatus 1, the first DC voltage is supplied to the main motor 160 without passing through the main board 110. This eliminates the need to connect the main board 110 and the main motor 160 with a harness or the like, reducing the amount of wiring on the main board 110 and allowing the main board 110 to be made more compact. As a result, the amount of work required to plug and unplug wiring when replacing the main board 110 can be reduced, and the ASIC 111 can be easily replaced. Furthermore, because the first DC voltage is not supplied to the main board 110, an unnecessarily high voltage is not supplied to the main board 110.

[0116] Furthermore, because the main motor drive circuit 122 is disposed on the sub-board 120, wiring connecting the main board 110 and the main motor 160 is not required, compared to a configuration in which the main motor drive circuit 122 is disposed on the main board 110, and the labor required to plug and unplug wiring when replacing the main board 110 can be reduced. This makes it easy to replace the ASIC 111. Furthermore, because the first DC voltage is not supplied to the main board 110, an unnecessarily high voltage is not supplied to the main board 110.

[0117] Furthermore, because DC / DC converter 121 that converts the first voltage into a second voltage that is lower is disposed on sub-board 120, the first voltage is not supplied to main board 110, and an unnecessarily high voltage is not supplied to main board 110. Furthermore, by supplying voltage from sub-board 120 to main board 110 and transmitting signals from main board 110 to sub-board 120 via a single main connector CM, the number of connectors and harnesses connected to main board 110 can be reduced, and ASIC 111 can be easily replaced.

[0118] Furthermore, since the high-voltage power supply board 150 receives the first DC voltage from the low-voltage power supply board 140 via the sub-board 120, without passing through the main board 110, the first voltage is not supplied to the main board 110, and an unnecessarily high voltage is not supplied to the main board 110. Furthermore, the wiring connected to the main board 110 can be reduced, and the ASIC 111 can be easily replaced.

[0119] Furthermore, since the first DC voltage is supplied to the polygon motor 53 from the low-voltage power supply board 140 via the sub-board 120 without passing through the main board 110, the first voltage is not supplied to the main board 110, and an unnecessarily high voltage is not supplied to the main board 110. Furthermore, the wiring connected to the main board 110 can be reduced, and the ASIC 111 can be easily replaced.

[0120] Furthermore, the sub-board 120 has a fifth connector C5 that is directly connected to the main connector CM without a harness, which reduces the number of harnesses required. Furthermore, the fifth connector C5 supports the main connector CM, which allows the main board 110 to be supported by the sub-board 120.

[0121] Furthermore, when the main board 110 is attached inside the main housing 10, the main board 110 is disposed so as to fit into the notch 120K, so that the main board 110 and the sub-board 120 can be disposed compactly.

[0122] Furthermore, since the area of ​​the main board 110 is smaller than the area of ​​the sub-board 120, the main board 110 can be easily replaced.

[0123] Furthermore, since the USB connection terminal 118 is exposed on the outer surface of the main body housing 10, it is easy to connect a USB connector.

[0124] Furthermore, since the LAN connection terminal 119 is exposed on the outer surface of the main body housing 10, it is easy to connect a LAN connector.

[0125] Furthermore, because main board 110 has authentication IC 113 for authenticating devices that communicate with ASIC 111, it is possible to prevent hacking and the intrusion of malicious programs. Furthermore, because authentication IC 113 can be replaced along with ASIC 111 when main board 110 is replaced, authentication IC 113 can always be updated to match the security performance required when replacing ASIC 111, and even if the product has a long lifespan, the performance and security of ASIC 111 can be maintained by replacing main board 110.

[0126] Although the embodiment has been described above, the image forming apparatus 1 can be modified as appropriate as exemplified below.

[0127] In the above-described embodiment, the main connector CM of the main board 110 and the first connector C1 of the sub-board 120 face each other in the second direction, but they may face each other in a direction different from the second direction. For example, if the main connector CM and the first connector C1 face each other in the first direction, the main board 110 is pulled out from the first direction.

[0128] In the above-described embodiment, the area of ​​the main board is smaller than the area of ​​the sub-board, but the area of ​​the main board may be the same as the area of ​​the sub-board, or may be larger than the area of ​​the sub-board.

[0129] In the above-described embodiment, the main board has an ASIC as the main control circuit, but the main board may have a main control circuit other than an ASIC, such as a CPU.

[0130] In the above-described embodiment, the main motor drives the photosensitive drum, but the main motor may also be configured to drive a transport unit and the like in addition to the photosensitive drum.

[0131] In the above-described embodiment, the image forming unit 40 is configured to perform so-called direct transfer, in which the toner image formed on the photosensitive drum 61 is transferred to the sheet S by the transfer roller 63. However, the image forming unit may also be configured to perform so-called intermediate transfer, in which the toner image formed on the photosensitive drum is transferred from the intermediate transfer belt to the sheet.

[0132] In the above-described embodiment, the image forming apparatus 1 is a monochrome printer, but the image forming apparatus may be, for example, a color printer. The image forming apparatus may also be a copier, a multifunction peripheral, or the like. In the embodiment, an electrophotographic image forming apparatus is exemplified, but the image forming apparatus may also be, for example, an inkjet image forming apparatus, a dot impact image forming apparatus, or the like.

[0133] The elements described in the embodiments and modifications may be implemented in any combination.

[0134] REFERENCE SIGNS LIST 1 image forming apparatus 10 main body housing 110 main board 111 ASIC 120 sub-board 140 low-voltage power supply board 141 AC / DC converter 160 main motor C1 first connector C2 second connector

Claims

1. An image forming apparatus comprising: a main body housing; a photosensitive drum rotatable around a rotation axis extending in a first direction; a main motor that provides driving force to the photosensitive drum; a low-voltage power supply board on which is mounted an AC / DC converter that converts AC voltage supplied from a commercial power source into DC voltage of a first voltage; a sub-board having a first connector to which a terminal of a harness connecting the low-voltage power supply board is connected and a second connector to which a terminal of a harness connecting the main motor is connected; and a main board that is detachably housed in the main body housing and has a main connector for electrically connecting an ASIC that controls the main motor to the sub-board, wherein DC voltage of the first voltage is supplied to the main motor from the low-voltage power supply board via the sub-board without passing through the main board, and the ASIC sends a control signal to the main motor via the main connector and the sub-board.

2. The image forming apparatus according to claim 1, wherein the sub-board further includes a main motor drive circuit that outputs drive power for driving the main motor, the main motor drive circuit is supplied with the first DC voltage from a low-voltage power supply board without passing through the main board, and the main board transmits a control signal for controlling the main motor to the main motor drive circuit via the main connector.

3. The image forming apparatus according to claim 1, wherein the sub-board further has a DC / DC converter that converts the first voltage into a second voltage that is lower than the first voltage, and the main board is supplied with a DC voltage of the second voltage via the main connector.

4. The image forming apparatus described in claim 1, further comprising a developing roller that supplies toner to the photosensitive drum, a charger that charges the photosensitive drum, and a transfer roller that transfers the toner image from the photosensitive drum to a sheet, wherein the ASIC controls the voltages applied to the developing roller, the charger, and the transfer roller via the main connector and the sub-board.

5. The image forming apparatus according to claim 4, further comprising a high-voltage power supply board on which a charging voltage application circuit that applies a charging voltage to the charger, a development voltage application circuit that applies a development voltage to the development roller, and a transfer voltage application circuit that applies a transfer voltage to the transfer roller are arranged, the high-voltage power supply board being connected to the sub-board via a harness, the sub-board having a third connector to which a terminal of the harness that connects the high-voltage power supply board is connected, the high-voltage power supply board is supplied with a first DC voltage from the low-voltage power supply board via the sub-board without passing through the main board, and the ASIC transmits control signals to the charging voltage application circuit, the development voltage application circuit, and the transfer voltage application circuit via the main connector and the sub-board.

6. The image forming apparatus according to claim 1, further comprising an exposure unit that exposes the photosensitive drum, the exposure unit having a light source device that emits laser light, a polygon mirror that deflects the laser light, and a polygon motor that rotates the polygon mirror; the sub-board further has a fourth connector to which a terminal of a harness that connects the polygon motor is connected; the polygon motor is supplied with a first DC voltage from the low-voltage power supply board via the sub-board without passing through the main board; and the ASIC sends a control signal to the polygon motor via the main connector and the sub-board.

7. The image forming apparatus according to claim 1, wherein the sub-board has a fifth connector that is connected directly to the main connector without a harness.

8. An image forming apparatus according to claim 7, wherein the main board faces the same direction as the sub-board, and the main connector is connected to the fifth connector in a direction along the surface of the sub-board.

9. The image forming device described in claim 1, characterized in that the main body housing has an attachment / detachment opening that opens in the vertical direction and in a second direction perpendicular to the first direction, and the main board can be removed by pulling it out of the attachment / detachment opening in the second direction.

10. An image forming apparatus as described in claim 9, characterized in that the sub-board has a notch recessed in the second direction, and the main board is positioned in the notch when installed inside the main body housing.

11. The image forming apparatus according to claim 1, wherein the area of ​​the main board is smaller than the area of ​​the sub-board.

12. The image forming apparatus according to claim 9, wherein the main board has a USB connection terminal to which a USB connector can be connected, and when the main board is attached to the main housing, the USB connection terminal is exposed on the outer surface of the main housing.

13. An image forming apparatus as described in claim 9, characterized in that the main board has a LAN connection terminal to which a LAN connector can be connected, and when the main board is attached to the main housing, the LAN connection terminal is exposed on the outer surface of the main housing.

14. The image forming apparatus according to claim 1, wherein the main board further comprises an authentication IC for authenticating devices that communicate with the ASIC.

15. The image forming apparatus described in claim 1, characterized in that the main body housing has a first region outside the photosensitive drum in the first direction and on one side of the photosensitive drum in the first direction, and a second region outside the photosensitive drum in the first direction and on the other side of the photosensitive drum in the first direction, and the main board, the sub-board and the main motor are all arranged in the first region.

16. The image forming apparatus according to claim 15, wherein the low-voltage power supply board is disposed in the second area.

Images