Image forming apparatus

Abstract

To provide an image forming apparatus that allows for easy replacement of the ASIC. [Solution] The image forming apparatus comprises a low-voltage power supply board 140, a sub-board 120, and a main board 110. The low-voltage power supply board 140 converts AC voltage to a first DC voltage. The sub-board 120 has a first connector C1 to which terminals of a harness connecting the low-voltage power supply board 140 are connected, and a second connector C2 to which terminals of a harness connecting the main motor 160 are connected. The main board 110 is detachably housed in the main body housing. The main board 110 electrically connects the ASIC 111, which controls the main motor 160, to the sub-board 120. 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. The ASIC 111 transmits control signals to the main motor 160 via the main connector CM and the sub-board 120.

Description

Technical Field

[0005] , , ,

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

Background Art

[0002] Conventionally, an image forming apparatus including a detachable main board has been known (see Patent Document 1). The main board has an ASIC (main control circuit) for controlling the image forming apparatus. The main board is connected to a plurality of electrical components such as an image forming unit and an operation panel, and is configured such that control signals, electric power, etc. are transmitted from the ASIC to the plurality of electrical components.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a conventional image forming apparatus, since the main board having an ASIC is connected to a plurality of electrical components, a lot of wirings are required. For this reason, when replacing the main board, it is necessary to disconnect and reconnect a lot of wirings, and there is a problem that it takes time to replace the ASIC. Therefore, an object of the present invention is to provide an image forming apparatus capable of easily replacing an ASIC.

Means for Solving the Problems

[0005] To solve the above problems, an 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 around a rotation axis extending in a first direction. The main motor provides driving force to the photosensitive drum. The low-voltage power supply board has an AC / DC converter that converts the AC voltage supplied from the commercial power supply into a DC voltage of the first voltage. The sub-board has a first connector to which the terminals of the harness connecting the low-voltage power supply board are connected, and a second connector to which the terminals of the harness connecting the main motor are connected. The main board is detachably housed in the main body housing. The main board electrically connects the ASIC that controls the main motor to the sub-board. The main motor receives its first voltage DC voltage via a sub-board from the low-voltage power supply board, bypassing the main board. The ASIC transmits control signals to the main motor via the main connector and sub-board.

[0006] The main motor is supplied with the first DC voltage without passing through the main board. Therefore, there is no need to connect the main board and the main motor with a harness, reducing the amount of wiring on the main board and allowing for a more compact design. As a result, the time and effort required to disconnect and reconnect wires when replacing the main board is reduced, making ASIC replacement easier. Furthermore, because the first DC voltage is not supplied to the main board, unnecessarily high voltages are not supplied to the main board.

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

[0008] Because the main motor drive circuit is located on a sub-board, compared to a configuration where the main motor drive circuit is located on the main board, wiring connecting the main board and the main motor is unnecessary, reducing the labor required to disconnect and reconnect wires when replacing the main board. This allows for easy replacement of the ASIC. Furthermore, because the first DC voltage is not supplied to the main board, unnecessarily high voltages are not supplied to the main board.

[0009] Furthermore, the sub-board may have a DC / DC converter that converts the first voltage to a second voltage lower than the first voltage. The main board may then be supplied with the second DC voltage via a main connector.

[0010] Because a DC / DC converter that converts the first voltage to a lower second voltage is located on the sub-board, the first voltage is never supplied to the main board, and unnecessarily high voltages are 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 a 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 the voltage applied to the developing roller, charger, and transfer roller via a main connector and a sub-board.

[0012] Furthermore, the image forming apparatus may further include a high-voltage power supply board on which a charging voltage application circuit for applying a charging voltage to a charger, a developing voltage application circuit for applying a developing voltage to a developing roller, and a transfer voltage application circuit for applying a transfer voltage to a transfer roller are arranged, and the high-voltage power supply board may be connected to a sub-board via a harness. The sub-board may have a third connector to which the terminals of the harness connecting the high-voltage power supply board are connected. The DC voltage of the first voltage may be supplied to the high-voltage power supply board from a low-voltage power supply board via the sub-board, without passing through the main board. The ASIC may be configured to transmit control signals to the charging voltage application circuit, the developing voltage application circuit, and the transfer voltage application circuit via the main connector and the sub-board.

[0013] In the high-voltage power supply board, the first DC voltage is supplied via a sub-board from the low-voltage power supply board, bypassing the main board. As a result, the first voltage is never supplied to the main board, preventing unnecessarily high voltages from being supplied to it. Furthermore, the wiring connected to the main board can be reduced, making it easier to replace the ASIC.

[0014] Furthermore, the image forming apparatus may further include an exposure unit for exposing a photosensitive drum, which comprises a light source device for emitting laser light, a polygon mirror for deflecting the laser light, and a polygon motor for rotating the polygon mirror. The sub-board may further have a fourth connector to which the terminals of a harness connecting the polygon motor are connected. The polygon motor may be supplied with a DC voltage of the first voltage from a low-voltage power supply board via the sub-board, without passing through the main board. The ASIC may be configured to transmit control signals to the polygon motor via the main connector and the sub-board.

[0015] In the polygon motor, the DC voltage of the first voltage is supplied from the low-voltage power supply board via a sub-board, without passing through the main board. Therefore, the first voltage is not supplied to the main board, and unnecessarily high voltages are not supplied to the main board. In addition, the wiring connected to the main board can be reduced, and the ASIC can be easily replaced.

[0016] Furthermore, the sub-board may have a fifth connector that connects directly to the main connector without going through a harness.

[0017] The sub-board has a fifth connector that connects directly to the main connector without going through a harness, thus reducing the number of harnesses. Furthermore, because the fifth connector supports the main connector, the main board can be supported by the sub-board.

[0018] Furthermore, the main board may be oriented in the same direction as the sub-board, and the main connector may be connected to the fifth connector in a direction aligned with the surface of the sub-board.

[0019] Furthermore, the main housing may have a removable opening that opens in the vertical direction and in a second direction perpendicular to the first direction. The main board may be removable by pulling it out in the second direction through the removable opening.

[0020] Furthermore, the sub-board may have a notch recessed in the second direction, and the main board may be positioned in the notch when mounted inside the main body housing.

[0021] When the main board is mounted inside the main unit casing, it is positioned within a notch, allowing for a compact arrangement of the main board and sub-boards.

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

[0023] Because the main board has a smaller surface area than the sub-board, the main board can be easily replaced.

[0024] Further, the main board may have a USB connection terminal to which a USB connector can be connected. And in a state where the main board is mounted on the main body housing, the USB connection terminal may be exposed on the outer surface of the main body housing.

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

[0026] Further, the main board may have a LAN connection terminal to which a LAN connector can be connected. And in a state where the main board is mounted on 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 the LAN connector.

[0028] Further, the main board may further have an authentication IC for authenticating a device that communicates with the ASIC.

[0029] Since the main board has an authentication IC for authenticating a device that communicates with the ASIC, it is possible to prevent hacking and prevent the intrusion of unauthorized programs. Also, since the authentication IC can be replaced together with the ASIC when replacing the main board, it is always possible to update to an authentication IC according to the security performance required when replacing the ASIC. By replacing the main board even when the product life is long, the performance and security performance of the ASIC can be maintained.

Advantages of the Invention

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

Brief Description of the Drawings

[0031] [Figure 1] It is a cross-sectional view showing an image forming apparatus according to an embodiment. [Figure 2]This is a perspective view showing the main board, sub-board, low-voltage power supply board, high-voltage power supply board, and main motor, among other components. [Figure 3] This block diagram shows the electrical connections and control signals for the main board, sub-board, low-voltage power supply board, high-voltage power supply board, and main motor. [Figure 4] This is a top view of an image forming apparatus, showing the positions of the main circuit board, sub-circuit board, low-voltage power supply board, high-voltage power supply board, and main motor. [Figure 5] This figure shows the state after removing the main circuit board from the state shown in Figure 4. [Figure 6] This is a view of the image forming apparatus from the left, showing the positional relationships of the main board, sub-board, low-voltage power supply board, high-voltage power supply board, and main motor. [Figure 7] This figure shows the state after removing the main circuit board from the state shown in Figure 6. [Modes for carrying out the invention]

[0032] Embodiments of this disclosure will be described in detail with reference to the drawings as appropriate. As shown in Figure 1, the image forming apparatus 1 is a monochrome printer. In the following description, the direction is defined as "front" when viewed from the user of the image forming apparatus 1 (right side in Figure 1) and "back" when viewed from the user (left side in Figure 1). The up-down direction is the vertical direction. The front-back direction is perpendicular to the up-down direction. Also, the left side (front side of the paper in Figure 1) when viewed from the user is defined as "left" and the right side (back side of the paper in Figure 1) is defined as "left".

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

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

[0035] The control panel 180 is located on the top surface 10A of the main housing 10. The control panel 180 can display various messages and allows commands to be input to the image forming apparatus 1. The control panel 180 is located towards the front of the main housing 10.

[0036] The sheet supply unit 30 supplies sheets S to the image forming unit 40. The sheet supply unit 30 is located in the lower part of the main housing 10. The sheet supply unit 30 comprises a sheet tray 31 and a sheet supply mechanism 32. The sheet tray 31 holds the sheets S supplied to the image forming unit 40. The sheet tray 31 is detachable from the main housing 10. When the sheet tray 31 is removed, it is pulled forward from the main housing 10. When the sheet tray 31 is attached to the main 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 transport roller, a separation roller 34, a separation pad 35, a first roller 36, and a registration roller 37. The pickup roller 33 feeds the sheet S contained in the sheet tray 31 toward the photosensitive drum 61. The separation roller 34 and separation pad 35 separate the sheet S fed by the pickup roller 33 into individual sheets. The first roller 36 and registration roller 37 transport the sheet S toward the image forming unit 40.

[0038] The image forming unit 40 forms an image on the sheet S. The image forming unit 40 comprises 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 housing 10. The exposure unit 50 includes 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 dashed line, the exposure unit 50 emits a light beam from the optical device 51, deflects it with the polygon mirror 52, and then exposes the surface of the photosensitive drum 61 of the image forming unit 40.

[0040] The process unit 60 is located within the main housing 10 between the exposure unit 50 and the sheet tray 31. The process unit 60 comprises 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 with the front cover 20 open. To remove the process unit 60, with the front cover 20 open, the process unit 60 is pulled forward from the main body housing 10. The developing unit 60B is detachable from the drum unit 60A with the process unit 60 removed from the main body housing 10. The drum unit 60A includes 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 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 explanation, the direction in which the rotation axis 61X of the photosensitive drum 61 extends is referred to as the "first direction." The vertical direction and the direction perpendicular to the first direction are referred to as the "second direction." The arrows in the figures indicate one side of each direction. The opposite direction of 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 being the left side and the other side of the second direction being the right side. The second direction is the front-back direction. In this embodiment, one side of the second direction is the rear side and the other side is the front side.

[0044] The developing unit 60B includes 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 within the main 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 unit 40, the exposure unit 50 emits a light beam onto the surface of the charged photosensitive drum 61. This forms an electrostatic latent image on the photosensitive drum 61 based on the image data. The developing roller 64 supplies toner to the surface of the exposed photosensitive drum 61. This forms a toner image on the photosensitive drum 61.

[0047] The photosensitive drum 61 and transfer roller 63 transport the sheet S supplied from the sheet supply unit 30. This transfers the toner image formed on the photosensitive drum 61 to the sheet S. The heating unit 71 and pressure roller 72 transport the sheet S on which the toner image has been transferred. This fixes the toner image transferred to the sheet S.

[0048] The discharge roller 81 is located above the fixing unit 70. The discharge roller 81 discharges the sheet S, on which the image has been formed in the image forming unit 40, to the discharge tray 13. The discharge tray 13 is formed on the top surface 10A of the main housing 10.

[0049] As shown in Figures 2 and 3, the image forming apparatus 1 comprises a main substrate 110, a sub-sub-substrate 120, a wireless substrate 130, a low-voltage power supply substrate 140, a high-voltage power supply substrate 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 the use of a harness. 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 the first harness H1. The sub-board 120 and the main motor 160 are connected via the second harness H2. The sub-board 120 and the high-voltage power supply board 150 are connected via the third harness H3. The sub-board 120 and the exposure unit 50 are connected via the fourth harness H4 and the fifth harness H5. The sub-board 120 and the control panel 180 are connected via the sixth harness H6.

[0052] The type of harness is optional, and it may be an FFC (Flexible Flat Cable).

[0053] Here, as shown in Figure 4, the main housing 10 has a first region RE1 and a second region RE2. The first region RE1 is the outer side of the photosensitive drum 61 in the first direction and is the region on one side of the photosensitive drum 61 in the first direction. The second region RE2 is the outer side of the photosensitive drum 61 in the first direction and is the region on the other side of the photosensitive drum 61 in the first direction.

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

[0055] The first harness H1 extends along the first direction from the first region RE1 to the second region RE2. More specifically, the first harness H1 extends from the first region RE1 to the second region RE2, passing through one side of the second direction from the rotation axis 61X of the photosensitive drum 61.

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

[0057] As shown in Figure 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. Also, 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, and the low-voltage power supply board 140.

[0058] The sub-substrate 120 has a notch 120K that is 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 elongated in the vertical direction. The second portion 120B extends from the top of the first portion 120A to one side in the second direction and has a rectangular shape that is elongated in the second direction. The third portion 120C extends from the bottom of the first portion 120A to one side in the second direction and has a rectangular shape that is elongated 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 casing 10, it is positioned in the notch 120K of the sub-board 120. In other words, when the main board 110 is installed inside the main casing 10, it is positioned between the second part 120B and the third part 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] As shown in Figure 3, the wireless board 130 has a wireless communication module 131. The wireless communication module 131 is capable of performing wireless communication to wirelessly connect the image forming apparatus 1 and wireless equipment. The wireless communication is, for example, wireless LAN standard wireless communication represented by Wi-Fi® communication.

[0062] Furthermore, the wireless communication module 131 may perform short-range wireless communication. Here, short-range wireless communication refers to NFC (Near Field Communication), a short-range wireless communication standard with a communication distance of approximately 10 cm or less, exemplified by ISO / IEC 18092, ISO / IEC 21481, etc., and includes technologies such as FeliCa (registered trademark) and Mifare (registered trademark). Bluetooth (registered trademark) may also be considered a type of short-range 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 an AC voltage supplied from the commercial power supply into a DC voltage of a first voltage. The first voltage is, for example, 24V. 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 detachably housed in the main body housing 10.

[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 boosts the first voltage supplied from the low-voltage power supply board 140 to generate a high voltage. The high-voltage power supply board 150 includes 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, 5kV to 8kV. 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, 300V to 500V. 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, around minus several thousand volts.

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

[0067] As shown in Figure 3, the main board 110 includes an ASIC 111, a subconverter 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] ROM 114 stores control programs and setting data for controlling the image forming apparatus 1. RAM 115 and non-volatile memory 116 are used as a work area from which the control program is read and as a storage area for temporarily storing image data included in the print job.

[0069] ASIC111 is a semiconductor integrated circuit for performing print control of the image forming apparatus 1. ASIC111 performs print control by performing calculations based on programs and data stored in ROM114, RAM115, and non-volatile memory116. In this embodiment, ASIC111 controls the operation panel 180, the exposure unit 50, and the main motor 160.

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

[0071] The authentication IC 113 is an IC used to authenticate the security of devices and networks that communicate with the ASIC 111. When a long period of time has passed since the start of use of the image forming apparatus 1, 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 located at one end of the main board 110 in the second direction. When the main board 110 is mounted in 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) in the second direction of the main body housing 10.

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

[0074] The LAN connection terminal 119 is a terminal to which a LAN connector can be connected. When a LAN connector is connected to the LAN connection terminal 119, the ASIC 111 can send and receive data with external devices.

[0075] The main connector CM is a connector that connects to the sub-board 120. The main connector CM faces the other side (forward) of the second direction. The main connector CM is connected to and disconnected from the 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 Figure 5, the main circuit board 110 is detachably housed in the main body housing 10. The main circuit board 110 is an easily replaceable circuit board. Specifically, the main body housing 10 has a second opening 12 and a rear cover 12A. The second opening 12 is a detachable opening formed in the first region RE1 that opens in a second direction. The second opening 12 is formed on the rear surface of the main body housing 10. The second opening 12 is an opening that allows the main circuit board 110 to be pulled out in the second direction and removed. The rear cover 12A is rotatable between a closed position that covers the second opening 12 (see Figure 4) and an open position that opens the second opening 12 (see Figure 5). As shown in Figure 5, when the rear cover 12A is in the closed position, the main circuit board 110 can be detached from the second opening 12.

[0077] As shown in Figure 3, the sub-board 120 does not have a main control circuit such as an ASIC or CPU. The sub-board 120 electrically connects to the main board 110 and several 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 Figure 3 is a block diagram showing the electrical connections of each board, so the positions of the connectors may differ from those in Figures 2 and 4.

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

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

[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 voltage DC voltage from the low-voltage power supply board 140. Based on the control signal sent from the ASIC 111, the polygon motor drive circuit 123 outputs drive power to the polygon motor 53.

[0081] The first connector C1 is a connector to which the terminals of the harness connecting the low-voltage power supply board 140 to the sub-board 120 are connected. The terminals of the 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 the terminals of the harness connecting the main motor 160 to the sub-board 120 are connected. The terminals of the 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 the terminals of the harness connecting the high-voltage power supply board 150 to the sub-board 120 are connected. The terminals of the third harness H3, which is an example of a harness, are connected to the third connector C3.

[0084] The fourth connector C4 is a connector to which the terminals of the harness connecting the polygon motor 53 of the exposure unit 50 to the sub-board 120 are connected. The terminals of the fourth harness H4, which is an example of a harness, are 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 main connector CM of the main board 110 is connected to the fifth connector C5. As shown in Figure 2, the main board 110 is directly connected to the fifth connector C5 without a harness.

[0086] In this embodiment, the main board 110 is arranged 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 they are facing each other. In other words, the fifth connector C5 faces one side in the second direction, for example, towards the rear.

[0087] The fifth connector C5 and the main connector CM are board-to-board connectors for connecting boards to each other. 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. The terminals of the fifth harness H5 are connected to the sixth connector C6.

[0089] Connector 7 C7 is a connector for connecting the control panel 180 to the sub-board 120. The terminals of harness 6 H6 are connected to connector 7 C7.

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

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

[0092] The main motor drive circuit 122 is powered by the low-voltage power supply board 140. More specifically, the main motor drive circuit 122 is supplied with a first voltage DC voltage from the AC / DC converter 141 via the first connector C1. In other words, the main motor 160 is supplied with the first voltage 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 receives a 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 to the main motor drive circuit 122 via the main connector CM to control the main motor 160. In this way, the main motor drive circuit 122 converts the first DC voltage into a drive voltage for the main motor 160 and outputs it based on the control signal sent from the ASIC 111.

[0094] The ASIC111 transmits control signals to the main motor 160 via the main connector CM and the sub-board 120. The ASIC111 also receives signals from the main motor 160 via the sub-board 120 and the main connector CM.

[0095] The polygon motor drive circuit 123 is powered by the low-voltage power supply board 140. More specifically, the polygon motor drive circuit 123 is supplied with a first voltage DC voltage from the AC / DC converter 141 via the first connector C1. In other words, the polygon motor 53 is supplied with the first voltage 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 a 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 to the polygon motor drive circuit 123 via the main connector CM to control the polygon motor 53. 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 ASIC111 transmits control signals to the polygon motor 53 via the main connector CM and the sub-board 120. The ASIC111 also receives signals 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 voltage DC voltage via the sub-board 120 from the low-voltage power supply board 140, bypassing the main board 110. The ASIC 111 controls the voltage 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 is powered from the low-voltage power supply board 140 via the sub-board 120, without going through the main board 110. The ASIC 111 transmits control signals 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 signals sent from the ASIC 111 via the sub-board 120. The ASIC 111 also receives signals from the charging voltage application circuit 151 via the sub-board 120.

[0100] The developing voltage application circuit 152 is powered from the low-voltage power supply board 140 via the sub-board 120, without going through the main board 110. The ASIC 111 transmits control signals 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 signals sent from the ASIC 111 via the sub-board 120. The ASIC 111 also receives signals from the developing voltage application circuit 152 via the sub-board 120.

[0101] The transfer voltage application circuit 153 is powered from the low-voltage power supply board 140 via the sub-board 120, without going through the main board 110. The ASIC 111 transmits control signals 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 signals sent from the ASIC 111 via the sub-board 120. The ASIC 111 also receives signals from the transfer voltage application circuit 153 via the sub-board 120.

[0102] The DC / DC converter 121 is powered by the low-voltage power supply board 140. More specifically, the DC / DC converter 121 is supplied with a first voltage DC voltage from the AC / DC converter 141 via the fourth connector C4 and the first connector C1. The DC / DC converter 121 converts the first voltage DC current 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 the control signal sent from the ASIC 111.

[0103] The ASIC111 communicates with the wireless communication module 131 via the sub-board 120.

[0104] The ASIC111 transmits control signals to the optical device 51 via the sub-board 120 to control the emission of laser light from the optical device 51. The ASIC111 also receives signals from the optical device 51 via the sub-board 120.

[0105] The ASIC111 can receive commands input to the control panel 180 via the sub-board 120 and can also send messages to the control panel 180.

[0106] Next, we will explain how to attach and detach the main board 110.

[0107] As shown in Figure 6, the main board 110 and the sub-board 120 are detachably housed in the main body housing 10. The main body housing 10 comprises a sheet metal 10B, a first rail RA1, and a second rail RA2.

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

[0109] The sub-board 120 is fixed to the main casing 10. Specifically, the sub-board 120 is fixed to the sheet metal 10B with four screws N. To remove the sub-board 120, the four screws N are removed, thereby detaching the sub-board 120 from the sheet metal 10B.

[0110] The main board 110 is fixed to the main body housing 10. The main board 110 is held at the top by the first rail RA1 and at the bottom by the second rail RA2, so as not to move in the vertical direction. Furthermore, the main board 110 is held so as not to move in the second direction because the main connector CM is connected to the first connector C1 of the sub-board 120.

[0111] When removing the main board 110 from the main housing 10, the rear cover 12A is moved from the closed position shown in Figure 4 to the open position shown in Figure 5. As shown in Figure 5, when the rear cover 12A is moved to the open position, 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, when the main board 110 is pulled backward, the connection between the main connector CM of the main board 110 and the first connector C1 of the sub-board 120 is released, allowing the main board 110 to move in the second direction along the first rail RA1 and the second rail RA2. As a result, the main board 110 can be pulled out to one side in the second direction, for example, backward.

[0113] As shown in Figure 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 Figure 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. At this point, the main connector CM of the main board 110 faces the first connector C1 of the sub-board 120, and when pushed further forward, the main connector CM is connected to the first connector C1.

[0114] As shown in Figure 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 the reference for positioning the main board 110 in the front-to-back direction. After attaching the main board 110 to the main housing 10, close the rear cover 12A (see Figure 5).

[0115] Based on the above, the following effects can be obtained in this embodiment. In the image forming apparatus 1, the main motor 160 is supplied with a DC voltage of the first voltage without passing through the main board 110. Therefore, there is no 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 making the main board 110 more compact. As a result, the amount of work required to disconnect and reconnect wires when replacing the main board 110 is reduced, and the ASIC 111 can be easily replaced. In addition, because the DC voltage of the first voltage is not supplied to the main board 110, unnecessarily high voltages are not supplied to the main board 110.

[0116] Furthermore, since the main motor drive circuit 122 is located on the sub-board 120, compared to a configuration where the main motor drive circuit 122 is located on the main board 110, wiring connecting the main board 110 and the main motor 160 is unnecessary, reducing the amount of work required to disconnect and reconnect wires when replacing the main board 110. As a result, the ASIC 111 can be easily replaced. In addition, since the first voltage DC voltage is not supplied to the main board 110, an unnecessarily high voltage is not supplied to the main board 110.

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

[0118] Furthermore, since the DC voltage of the first voltage is supplied to the high-voltage power supply board 150 via the sub-board 120 from the low-voltage power supply board 140, 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. In addition, the wiring connected to the main board 110 can be reduced, and the ASIC 111 can be easily replaced.

[0119] Furthermore, since the polygon motor 53 receives the first DC voltage via the sub-board 120 from the low-voltage power supply board 140, without passing through the main board 110, the first voltage is never supplied to the main board 110, and unnecessarily high voltages are not supplied to the main board 110. In addition, the wiring connected to the main board 110 can be reduced, and the ASIC 111 can be easily replaced.

[0120] Furthermore, since the sub-board 120 has a fifth connector C5 that connects directly to the main connector CM without going through a harness, the number of harnesses can be reduced. Also, because the fifth connector C5 supports the main connector CM, the main board 110 can be supported by the sub-board 120.

[0121] Furthermore, when the main board 110 is installed inside the main body casing 10, the main board 110 is positioned within the notch 120K, allowing for a compact arrangement of the main board 110 and the sub-board 120.

[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 unit casing 10, it is easy to connect the USB connector.

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

[0125] Furthermore, since the main board 110 has an authentication IC 113 for authenticating devices that communicate with the ASIC 111, hacking and the intrusion of malicious programs can be prevented. In addition, since the authentication IC 113 can be replaced along with the ASIC 111 when the main board 110 is replaced, the authentication IC 113 can always be updated to meet the security performance requirements when the ASIC 111 is replaced. Even in the case of a long product lifespan, the performance and security performance of the ASIC 111 can be maintained by replacing the main board 110.

[0126] Although embodiments have been described above, the image forming apparatus 1 can be modified as appropriate as shown below.

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

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

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

[0130] In the embodiment described above, the main motor drove the photosensitive drum, but the main motor may also be configured to drive other components such as the transport unit.

[0131] In the above-described embodiment, the image forming unit 40 was configured to perform a 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 include an intermediate transfer belt, and the toner image formed on the photosensitive drum is transferred to the sheet from the intermediate transfer belt, a configuration known as an intermediate transfer.

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

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

[0134] 1. Image forming apparatus 10 Main Unit 110 Main board 111 ASIC 120 Sub-boards 140 Low-voltage power supply board 141 AC / DC Converter 160 Main motor C1 First Connector C2 Second Connector

Claims

1. The main casing and A photosensitive drum that can rotate around a rotation axis extending in the first direction, A main motor that provides driving force to the photosensitive drum, A low-voltage power supply board is provided, which includes an AC / DC converter that converts the AC voltage supplied from the commercial power supply into a DC voltage for the first voltage, A sub-board having a first connector to which the terminals of the harness connecting the low-voltage power supply board are connected, and a second connector to which the terminals of the harness connecting the main motor are connected, A main board that is detachably housed in the main body housing, comprising a main board having a main connector for electrically connecting the ASIC that controls the main motor and the sub-board, The main motor is supplied with a first voltage DC voltage, which bypasses the main board and is supplied from the low-voltage power supply board via the sub-board. The image forming apparatus is characterized in that the ASIC transmits control signals to the main motor via the main connector and the sub-board.

2. 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 DC voltage of the first voltage from the low-voltage power supply board without passing through the main board. The image forming apparatus according to claim 1, characterized in that the main board transmits a control signal for controlling the main motor to the main motor drive circuit via the main connector.

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

4. A developing roller that supplies toner to the photosensitive drum, A charger for charging the photosensitive drum, The system further comprises a transfer roller for transferring a toner image from the photosensitive drum to a sheet, The image forming apparatus according to claim 1, characterized in that the ASIC controls the voltage applied to the developing roller, the charger, and the transfer roller via the main connector and the sub-board.

5. A high-voltage power supply board comprising a charging voltage application circuit for applying a charging voltage to the charger, a developing voltage application circuit for applying a developing voltage to the developing roller, and a transfer voltage application circuit for applying a transfer voltage to the transfer roller, further comprising a high-voltage power supply board connected to the sub-board via a harness, The sub-board has a third connector to which the terminals of the harness connecting the high-voltage power supply board are connected. The high-voltage power supply board receives the first voltage DC voltage via the sub-board, without passing through the main board. The image forming apparatus according to claim 4, characterized in that the ASIC transmits control signals to the charging voltage application circuit, the developing voltage application circuit, and the transfer voltage application circuit via the main connector and the sub-board.

6. An exposure unit for exposing the photosensitive drum, further comprising: 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 the terminals of the harness connecting the polygon motor are connected. The polygon motor is supplied with a DC voltage of the first voltage not through the main board, but from the low-voltage power supply board via the sub-board. The image forming apparatus according to claim 1, characterized in that the ASIC transmits control signals to the polygon motor via the main connector and the sub-board.

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

8. The main board is oriented in the same direction as the sub-board. The image forming apparatus according to claim 7, characterized in that the main connector is connected to the fifth connector in a direction along the surface of the sub-board.

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

10. The sub-substrate has a notch recessed in the second direction, The image forming apparatus according to claim 9, characterized in that the main board is positioned in the notch when mounted inside the main housing.

11. The image forming apparatus according to claim 1, characterized in that the area of ​​the main substrate is smaller than the area of ​​the sub-substrate.

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

13. The main board has a LAN connection terminal to which a LAN connector can be connected. The image forming apparatus according to claim 9, characterized in that the LAN connection terminal is exposed on the outer surface of the main body housing when the main board is mounted in the main body housing.

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

Images