Image forming device

Abstract

Provided is an image forming device in which an ASIC can be easily replaced.　The image forming device comprises: a main motor 160; a main substrate 110 that is freely attachable to and detachable from a body housing 10; and a connector substrate 120. The connector substrate 120 has a first connector C1 and a second connector C2. The main substrate 110 is directly connected to the first connector C1 without going through a harness. A terminal of a first harness H1, to which the main motor 160 is connected, is connected to the second connector C2. An ASIC 111 transmits a control signal to the main motor 160 via the first connector C1 and the second connector C2.

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, so replacing the ASIC requires disconnecting all connections between the main board and the multiple electrical components. When disconnecting the harness connecting the electrical components from the main board, it is necessary to hold the main board while disconnecting the harness, which creates a problem of time and effort when replacing the ASIC.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus in which the ASIC can be easily replaced.

[0006] In order to solve the above problems, the image forming apparatus according to the present invention includes a main body housing, an image forming unit having a photosensitive drum, a main motor, a main board, and a connector board. The exposure unit exposes the photosensitive drum. The main motor provides driving force to the photosensitive drum. The main board is detachably housed in the main body housing. An ASIC that controls the exposure unit and the main motor is disposed on the main board. The connector board has a first connector and a second connector. The main board is directly connected to the first connector without a harness. A terminal of a first harness that connects the main motor is connected to the second connector. The ASIC sends a control signal to the main motor via the first connector and the second connector.

[0007] When replacing the main board on which the ASIC is mounted, there is no need to disconnect the terminals of the first harness, so the ASIC can be easily replaced.

[0008] The image forming unit may further include an exposure unit that exposes the photosensitive drum, and the connector board may further include a third connector to which a terminal of a second harness that connects the exposure unit is connected, and the ASIC may be configured to transmit a control signal to the exposure unit via the first connector and the third connector.

[0009] When replacing the main board on which the ASIC is mounted, there is no need to disconnect the terminals of the second harness, so the ASIC can be easily replaced.

[0010] The power supply circuit board may further include a low-voltage power supply board on which an AC / DC converter is disposed that converts AC voltage supplied from a commercial power source into DC voltage of the first voltage, and the connector board may include a fourth connector disposed thereon to which a terminal of a third harness that connects the low-voltage power supply board is connected.

[0011] The connector board has a fourth connector to which the terminal of the third harness that connects the low-voltage power supply board is connected, so when replacing the main board on which the ASIC is mounted, there is no need to remove the terminal of the third harness.

[0012] The main board may further include a main motor drive circuit that outputs drive power to the main motor. The main motor drive circuit may be configured to receive a DC voltage of the first voltage from the AC / DC converter via the fourth connector and the first connector, and to output drive power to the main motor based on a control signal sent from the ASIC.

[0013] Since the main motor drive circuit is disposed on the main board, the main motor drive circuit can be easily replaced by replacing the main board.

[0014] 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 to a sheet together with the photosensitive drum. The ASIC may be configured to control voltages applied to the developing roller, the charger, and the transfer roller.

[0015] The image forming unit may further include an exposure unit that exposes the photosensitive drum. The exposure unit may include 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 main board may further include a polygon motor drive circuit that outputs drive power to the polygon motor. The polygon motor drive circuit may be configured to receive a first DC voltage from the AC / DC converter via the fourth connector and the first connector, and to output drive power to the polygon motor based on a control signal sent from the ASIC via the first connector and the third connector.

[0016] Since the polygon motor drive circuit is disposed on the main board, the polygon motor drive circuit can be easily replaced by replacing the main board.

[0017] 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 developing voltage application circuit that applies a developing voltage to the developing roller, and a transfer voltage application circuit that applies a transfer voltage to the transfer roller are arranged, and which is connected to the connector board via a fourth harness. The connector board may have a fifth connector to which a terminal of the fourth harness is connected. The charging voltage application circuit may output the charging voltage based on a control signal sent from the ASIC via the first connector and the fifth connector. The developing voltage application circuit may output the developing voltage based on a control signal sent from the ASIC via the first connector and the fifth connector. The transfer voltage application circuit may output the transfer voltage based on a control signal sent from the ASIC via the first connector and the fifth connector.

[0018] The connector board has a fifth connector to which the terminal of the fourth harness that connects the high-voltage power supply board is connected, so when replacing the main board on which the ASIC is mounted, there is no need to disconnect the terminal of the fourth harness.

[0019] The sheet conveying device may further include a conveying roller that receives driving force from the main motor to convey the sheet, and an electric clutch that is switchable between a transmission state in which the driving force from the main motor is transmitted to the conveying roller and a disconnection state in which the driving force from the main motor is not transmitted to the conveying roller. The connector board may have a sixth connector, and a terminal of a fifth harness that connects the electric clutch may be connected to the sixth connector. The electric clutch may be configured to be switched between the transmission state and the disconnection state based on a control signal sent from the ASIC via the first connector and the sixth connector.

[0020] The connector board has a sixth connector to which the terminal of the fifth harness that connects the electric clutch is connected, so when replacing the main board on which the ASIC is mounted, there is no need to disconnect the terminal of the fifth harness.

[0021] The conveying rollers may also include a pickup roller that feeds the sheets stored in the sheet tray toward the photosensitive drum.

[0022] The electric clutch may be configured so that the first DC voltage is supplied from the low-voltage power supply board via the fourth connector and the sixth connector without passing through the first connector.

[0023] The electric clutch is supplied with the first DC voltage without passing through the main board, which simplifies the wiring of the connector board.

[0024] The ASIC may further include a wireless communication module capable of performing wireless communication. The connector board may have a seventh connector disposed thereon to which the wireless communication module is directly connected without a harness. The ASIC may perform wireless communication with the wireless communication module via the first connector and the seventh connector.

[0025] The connector board has a seventh connector for connecting the wireless communication module, so there is no need to disconnect the seventh connector when replacing the main board on which the ASIC is mounted. In addition, the wireless communication module is connected directly to the seventh connector without a harness, which reduces the number of harnesses required.

[0026] The device may further include an operation panel. The connector board may have an eighth connector, and the eighth connector may be connected to a terminal of a sixth harness that connects the operation panel. The ASIC may be configured to receive commands input to the operation panel via the eighth connector and the first connector.

[0027] Since the connector board has an eighth connector for connecting the operation panel arranged thereon, there is no need to remove the eighth connector when replacing the main board on which the ASIC is arranged.

[0028] The image forming unit may further include an exposure unit that exposes the photosensitive drum. The first connector may include a power connector having a terminal for sending power and a signal connector having a terminal for sending control signals without sending power. The power connector may have a terminal for outputting drive power from the main board to the main motor. The signal connector may have a terminal for outputting control signals for controlling the exposure unit from the main board.

[0029] By concentrating as many terminals for sending power as possible in the power connector and as many terminals for sending digital signals as possible in the signal connector, it is possible to reduce the amount of radio wave shielding placed between the power and signal paths in the first connector, thereby making the entire first connector more compact.

[0030] The photosensitive drum may be rotatable about a rotation axis extending in the first direction. The main body housing may have a first region on one side of the photosensitive drum in the first direction, outside the photosensitive drum in the first direction, and a second region on the other side of the photosensitive drum in the first direction, outside the photosensitive drum in the first direction. The main board, connector board, and main motor may all be arranged in the first region.

[0031] Since the main board, connector board, and main motor are all arranged in the first area, the harness connecting the main board, connector board, and main motor can be shortened.

[0032] In addition, the connector board may be located between the main board and the main motor in the vertical direction and in a second direction perpendicular to the first direction.

[0033] In the second direction, since the connector board is located between the main board and the main motor, the harness connecting the connector board and the main motor can be shortened.

[0034] The main board may have a main connector that is detachable from the first connector in the second direction, and may be configured to be detachable from the connector board in the second direction.

[0035] Since the main board is attached to and detached from the connector board in the second direction, no large opening is required when attaching and detaching the main board.

[0036] The power supply may further include a low-voltage power supply board on which an AC / DC converter is disposed that converts AC voltage supplied from a commercial power source into DC voltage of the first voltage. The low-voltage power supply board may be located in the second area and may overlap with the connector board when viewed from the first direction.

[0037] By positioning the low-voltage power supply board in the second area, interference between the main board and the connector board can be suppressed. Also, because the low-voltage power supply board overlaps with the connector board when viewed from the first direction, the harness connecting the low-voltage power supply board and the connector board can be shortened.

[0038] The connector board may be located on one side of the rotation axis of the photosensitive drum in a second direction perpendicular to the up-down direction and the first direction, and the third harness may extend from the first region to the second region, passing on the one side of the rotation axis of the photosensitive drum in the second direction.

[0039] The sheet conveying device may further include a pickup roller that receives a driving force from the main motor and feeds the sheets stored in the sheet tray toward the photosensitive drum, and an electric clutch that can be switched between a transmission state in which the driving force from the main motor is transmitted to the pickup roller and a cut-off state in which the driving force from the main motor is not transmitted to the pickup roller. The electric clutch may be disposed in the first region, and the main motor may be positioned between the connector board and the electric clutch in the second direction.

[0040] The image forming apparatus may further include a high-voltage power supply circuit 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, and which is connected to the connector board via a fourth harness. The high-voltage power supply circuit board may be arranged in the second region.

[0041] By arranging the high-voltage power supply board in the second area, it is possible to prevent the main board and the connector board from interfering with the high-voltage power supply board.

[0042] According to the present invention, it is possible to provide an image forming apparatus in which the ASIC can be easily replaced.

[0043] 1 is a cross-sectional view showing an image forming apparatus according to a first embodiment; FIG. 2 is a perspective view showing a main board, connector board, low-voltage power supply board, high-voltage power supply board, and main motor; FIG. 3 is a block diagram showing electrical connections and control signals for the main board, connector board, low-voltage power supply board, high-voltage power supply board, and main motor; FIG. 4 is a top view of the image forming apparatus, showing the positions of the main board, connector board, low-voltage power supply board, high-voltage power supply board, and main motor; FIG. 5 is a view showing a state in which the main board has been removed from the state shown in FIG. 5; FIG. 6 is a view of the image forming apparatus from the left, showing the positional relationships between the main board, connector board, low-voltage power supply board, high-voltage power supply board, and main motor; FIG. 7 is a view showing a process of removing the main board from the state shown in FIG. 6; FIG. 8 is a view of the image forming apparatus from the left, showing the positional relationships between the main board, connector board, main motor, electric clutch, and gear train; FIG. 9 is a perspective view (a) showing a state in which the main board is attached to a main body housing, and FIG. 10 is a perspective view (b) showing a state in which the main board has been removed from the main body housing. 1A is a perspective view showing a state in which the main board is attached to a main body housing in a configuration in which the main board and the enclosure are integrated, and FIG. 1B is a perspective view showing a state in which the main board is removed from the main body housing. FIG. 1B is a block diagram corresponding to FIG. 3 in a configuration in which the power connector and the signal connector C12 are combined into one connector. FIG. 1C is a block diagram corresponding to FIG. 3 in a configuration in which a wireless communication module is arranged on the main board.

[0044] A first embodiment of the present disclosure will be described in detail with appropriate reference to the drawings. 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."

[0045] 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 .

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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 onto the sheet S together with the photosensitive drum 61.

[0055] 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.

[0056] 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 and regulates the thickness of the toner on the developing roller 64 to a constant thickness.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] As shown in Figures 2 and 3, the image forming apparatus 1 includes a main board 110, a connector board 120, a wireless board 130, a low-voltage power supply board 140, a high-voltage power supply board 150, a main motor 160, an electric clutch 170, a gear train 190 (see Figure 8), a first harness H1, a second harness H2, a third harness H3, a fourth harness H4, a fifth harness H5, a sixth harness H6, and a seventh harness H7.

[0062] The main board 110 and the connector board 120 are connected directly without a harness. The connector board 120 and the wireless board 130 are connected directly without a harness. The connector board 120 and the main motor 160 are connected via a first harness H1. The connector board 120 and the exposure unit 50 are connected via a second harness H2 and a seventh harness H7. The connector board 120 and the low-voltage power supply board 140 are connected via a third harness H3. The connector board 120 and the high-voltage power supply board 150 are connected via a fourth harness H4. The connector board 120 and the electric clutch 170 are connected via a fifth harness H5. The connector board 120 and the operation panel 180 are connected via a sixth harness H6.

[0063] The type of harness is arbitrary, and the harness may be an FFC (flexible flat cable).

[0064] 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.

[0065] The main board 110, connector board 120, wireless board 130, main motor 160, and electric clutch 170 are all arranged in the first region RE1. The low-voltage power supply board 140 and high-voltage power supply board 150 are arranged in the second region RE2.

[0066] The third harness H3 extends from the first region RE1 to the second region RE2 along the first direction. Specifically, the third harness H3 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.

[0067] The main board 110 and the connector 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 connector board 120 are located on one side in the second direction of the photosensitive drum 61. In addition, in the second direction, the connector board 120 is located between the main board 110 and the main motor 160. In addition, in the second direction, the main motor 160 is located between the connector board 120 and the electric clutch 170.

[0068] 6 , when viewed from the first direction, the low-voltage power supply board 140 overlaps with the main board 110 and the connector board 120. Furthermore, when viewed from the first direction, the high-voltage power supply board 150 does not overlap with the main board 110, the connector board 120, or the low-voltage power supply board 140.

[0069] The main board 110 and the connector board 120 are rectangular with their long sides in the vertical direction. The vertical dimension of the connector board 120 is the same as the vertical dimension of the main board 110. The dimension of the connector board 120 in the second direction is smaller than the dimension of the main board 110 in the second direction.

[0070] 9A, the main body housing 10 has an enclosure EN. The enclosure EN is fixed to the main body housing 10. The enclosure EN is a metal case that houses the main board 110. When the main board 110 is attached to the main body housing 10, the main board 110 is covered and protected by the enclosure EN.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] The high-voltage power supply board 150 is detachably housed in the main body housing 10. 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.

[0075] 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.

[0076] 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.

[0077] The electric clutch 170 is switchable between a transmission state in which the driving force from the main motor 160 is transmitted to the pickup roller 33 and a disconnection state in which the driving force from the main motor 160 is not transmitted to the pickup roller 33 .

[0078] As shown in FIG. 8, the gear train 190 has a first gear G1, a second gear G2, a third gear G3, a fourth gear G4, a fifth gear G5, a sixth gear G6, and a seventh gear G7.

[0079] The first gear G1 meshes with a motor gear MG provided on the output shaft of the main motor 160. The second gear G2 meshes with the first gear G1. The third gear G3 meshes with the second gear G2. The fourth gear G4 meshes with the third gear G3. The fifth gear G5 meshes with the fourth gear G4. The sixth gear G6 meshes with the fifth gear G5. The seventh gear G7 meshes with the sixth gear G6.

[0080] The driving force of the main motor 160 is input to the electric clutch 170 through the seventh gear G7.

[0081] The image forming apparatus 1 further includes a tenth gear G10. The tenth gear G10 is in mesh with the first gear G1. Although not shown, the driving force of the main motor 160 is transmitted to the photosensitive drum 61, the developing roller 64, the pressure roller 72, the discharge roller 81, and the like via the first gear G1 and the tenth gear G10.

[0082] The electric clutch 170 and the gear train 190 are located on the other side of the main motor 160 in the second direction.

[0083] As shown in FIG. 3, the main board 110 has an ASIC 111, a main motor drive circuit 112, a polygon motor drive circuit 113, a ROM 114, a RAM 115, a non-volatile memory 116, a DC / DC converter 117, a USB connector 118, a LAN connector 119, and a main connector CM.

[0084] 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.

[0085] 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, the main motor 160, and the electric clutch 170.

[0086] The main motor drive circuit 112 is a circuit that drives and controls the main motor 160. Specifically, the main motor drive circuit 112 is supplied with a first DC voltage from the low-voltage power supply board 140. The main motor drive circuit 112 outputs drive power to the main motor 160 based on a control signal sent from the ASIC 111.

[0087] The DC / DC converter 117 is a converter that converts the second voltage into a third voltage that is lower than the second voltage. For example, the third voltage is 1.1 V. In other words, in this embodiment, the ASIC 111 is supplied with the 1.1 V voltage converted by the DC / DC converter 117.

[0088] The USB connector 118 and the LAN connector 119 are disposed at one end of the main board 110 in the second direction. The USB connector 118 and the LAN connector 119 are exposed to the outside of the main body housing 10 from one side (rear side) of the main body housing 10 in the second direction.

[0089] The USB connector 118 is a connector to which a USB terminal of an external device such as a PC is connected. When the USB connector 118 is connected to the USB terminal of the external device, the ASIC 111 can send and receive data to and from the external device.

[0090] A LAN cable is connected to the LAN connector 119. When the LAN cable is connected to the LAN connector 119, the ASIC 111 can transmit and receive data to and from external devices.

[0091] The polygon motor drive circuit 113 is a circuit that drives and controls the polygon motor 53. Specifically, the polygon motor drive circuit 113 is supplied with a first DC voltage from the low-voltage power supply board 140. The polygon motor drive circuit 113 outputs drive power to the polygon motor 53 based on a control signal sent from the ASIC 111.

[0092] The main connector CM is a connector that is connected to the connector board 120. The main connector CM is connected to the connector 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 first connector C1 of the connector board 120, which will be described later, in the second direction. The main connector CM has a first main connector CM1 and a second main connector CM2.

[0093] 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 an opening formed in the first region RE1. The second opening 12 is formed on the rear surface of the main body housing 10. The second opening 12 is an opening for attaching and detaching the main board 110. 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.

[0094] As shown in Figure 3, the connector board 120 does not have a control device or main control circuit such as an ASIC or CPU. The connector board 120 electrically connects the main board 110 to multiple electrical components. The connector board 120 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, and therefore the positions of each connector differ from those in Figures 2 and 4.

[0095] The first connector C1 is a connector for connecting the main board 110 to the connector board 120. The main connector CM of the main board 110 is connected to the first connector C1. As shown in FIG. 2 , the main board 110 is directly connected to the first connector C1 without a harness. In this embodiment, the first connector C1 faces the main connector CM in the second direction, and the first connector C1 and the main connector CM face each other. That is, the first connector C1 faces one side of the second direction, for example, rearward.

[0096] The first connector C1 and the main connector CM are board-to-board connectors for connecting the boards together. At least one of the first connector C1 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 connector board 120.

[0097] The first connector C1 has a power connector C11 and a signal connector C12. The power connector C11 is connected to the first main connector CM1. The signal connector C12 is connected to the second main connector CM2.

[0098] The power connector C11 is a connector having terminals for transmitting power. In this embodiment, the power connector C11 transmits the first DC voltage supplied from the low-voltage power supply board 140, the drive voltages supplied from the main motor drive circuit 112 and the polygon motor drive circuit 113, control signals used by the ASIC 111 to control the high-voltage power supply board 150, and control signals used by the ASIC 111 to control the electric clutch 170. In this manner, the power connector C11 transmits power and control signals. The power connector C11 has terminals for transmitting power and terminals for transmitting control signals. The power connector C11 has more terminals than the signal connector C12. Note that the power connector C11 may also have a ground terminal in addition to the terminals for transmitting power and signals.

[0099] The signal connector C12 is a connector that does not transmit power and has a terminal for transmitting control signals. In this embodiment, the signal connector C12 transmits signals that the ASIC 111 uses to communicate with the wireless communication module 131, control signals that the ASIC 111 uses to control the optical device 51, and signals that the ASIC 111 uses to communicate with the operation panel 180. In this way, the signal connector C12 does not transmit power but transmits control signals. The signal connector C12 has a terminal for transmitting control signals. Note that the signal connector C12 may further have a ground terminal in addition to the terminal for transmitting signals.

[0100] 3, the second connector C2 is a connector for connecting the main motor 160 to the connector board 120. A terminal of the first harness H1 is connected to the second connector C2.

[0101] The third connector C3 is a connector for connecting the polygon motor 53 of the exposure unit 50 to the connector board 120. A terminal of the second harness H2 is connected to the third connector C3.

[0102] The fourth connector C4 is a connector for connecting the low-voltage power supply board 140 to the connector board 120. A terminal of the third harness H3 is connected to the fourth connector C4.

[0103] The fifth connector C5 is a connector for connecting the high-voltage power supply board 150 to the connector board 120. A terminal of the fourth harness H4 is connected to the fifth connector C5.

[0104] The sixth connector C6 is a connector for connecting the electric clutch 170 to the connector board 120. A terminal of the fifth harness H5 is connected to the sixth connector C6.

[0105] The seventh connector C7 is a connector for connecting the wireless communication module 131. The seventh connector C7 is connected to the wireless connector CW of the wireless board 130. That is, the wireless board 130 is directly connected to the seventh connector C7 without using a harness. In this embodiment, the seventh connector C7 and the wireless connector CW face each other in the first direction. That is, the seventh connector C7 faces one side of the first direction, for example, the left. The seventh connector C7 is a board-to-board connector for connecting boards to each other.

[0106] The eighth connector C8 is a connector for connecting the operation panel 180 to the connector board 120. A terminal of the sixth harness H6 is connected to the eighth connector C8.

[0107] The ninth connector C9 is a connector for connecting the optical device 51 of the exposure unit 50 to the connector board 120. A terminal of the seventh harness H7 is connected to the ninth connector C9.

[0108] 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.

[0109] The main motor drive circuit 112 receives power from the low-voltage power supply board 140 via the connector board 120. More specifically, the main motor drive circuit 112 receives a first DC voltage from the AC / DC converter 141 via the fourth connector C4 and the first connector C1. Based on a control signal sent from the ASIC 111, the main motor drive circuit 112 converts the first DC voltage into a drive voltage for the main motor 160 and outputs it. The ASIC 111 sends the control signal to the main motor 160 via the first connector C1 and the second connector C2. The ASIC 111 also receives a signal from the main motor 160 via the second connector C2 and the first connector C1.

[0110] The polygon motor drive circuit 113 receives power from the low-voltage power supply board 140 via the connector board 120. More specifically, the polygon motor drive circuit 113 receives a first DC voltage from the AC / DC converter 141 via the fourth connector C4 and the first connector C1. Based on a control signal sent from the ASIC 111, the polygon motor drive circuit 113 converts the first DC voltage into a drive voltage for the polygon motor 53 and outputs it. The ASIC 111 sends a control signal to the polygon motor 53 via the first connector C1 and the third connector C3. The ASIC 111 also receives a signal from the polygon motor 53 via the third connector C3 and the first connector C1.

[0111] The charging voltage application circuit 151 receives power from the low-voltage power supply board 140 via the connector board 120, without passing through the main board 110. More specifically, the charging voltage application circuit 151 receives a first DC voltage from the AC / DC converter 141 via the fourth connector C4 and the fifth connector C5. The charging voltage application circuit 151 outputs a charging voltage to the charger 62 based on a control signal sent from the ASIC 111 via the first connector C1 and the fifth connector C5. The ASIC 111 also receives a signal from the charging voltage application circuit 151 via the fifth connector C5 and the first connector C1.

[0112] The developing voltage application circuit 152 receives power from the low-voltage power supply board 140 via the connector board 120, without passing through the main board 110. More specifically, the developing voltage application circuit 152 receives a first DC voltage from the AC / DC converter 141 via the fourth connector C4 and the fifth connector C5. The developing voltage application circuit 152 outputs a developing voltage to the developing roller 64 based on a control signal sent from the ASIC 111 via the first connector C1 and the fifth connector C5. The ASIC 111 also receives a signal from the developing voltage application circuit 152 via the fifth connector C5 and the first connector C1.

[0113] The transfer voltage application circuit 153 receives power from the low-voltage power supply board 140 via the connector board 120, without passing through the main board 110. More specifically, the transfer voltage application circuit 153 receives a first DC voltage from the AC / DC converter 141 via the fourth connector C4 and the fifth connector C5. The transfer voltage application circuit 153 outputs a transfer voltage to the transfer roller 63 based on a control signal sent from the ASIC 111 via the first connector C1 and the fifth connector C5. The ASIC 111 also receives a signal from the transfer voltage application circuit 153 via the fifth connector C5 and the first connector C1.

[0114] The DC / DC converter 117 is supplied with power from the low-voltage power supply board 140 via the connector board 120. More specifically, the DC / DC converter 117 is supplied with a direct current voltage of the second voltage from the AC / DC converter 141 via the fourth connector C4 and the first connector C1. The DC / DC converter 117 converts the direct current of the second voltage into a third voltage and outputs it to the ASIC 111. The amount of power supplied from the low-voltage power supply board 140 to the DC / DC converter 117 and the like is adjusted based on a control signal sent from the ASIC 111.

[0115] The ASIC 111 communicates with the wireless communication module 131 via the connector board 120. Specifically, the ASIC 111 performs wireless communication with the wireless communication module 131 via the first connector C1 and the seventh connector C7.

[0116] The ASIC 111 transmits a control signal to the optical device 51 via the connector board 120 and controls the emission of laser light from the optical device 51. Specifically, the ASIC 111 transmits a control signal to the optical device 51 via the first connector C1 and the ninth connector C9 and controls the emission of laser light from the optical device 51. The ASIC 111 also receives a signal from the optical device 51 via the ninth connector C9 and the first connector C1.

[0117] The electric clutch 170 is supplied with a first DC voltage from the low-voltage power supply board 140 via the fourth connector C4 and the sixth connector C6 without passing through the first connector C1. The ASIC 111 transmits a control signal to the electric clutch 170 via the connector board 120. More specifically, the ASIC 111 transmits a control signal to the electric clutch 170 via the first connector C1 and the sixth connector C6. That is, the electric clutch 170 is switched between a transmission state and a disconnection state based on the control signal transmitted from the ASIC 111 via the first connector C1 and the sixth connector C6. The ASIC 111 also receives a signal from the electric clutch 170 via the sixth connector C6 and the first connector C1.

[0118] The ASIC 111 can receive commands input to the operation panel 180 via the connector board 120 and can also send messages to the operation panel 180. Specifically, the ASIC 111 receives commands input to the operation panel 180 via the eighth connector C8 and the first connector C1. The ASIC 111 also sends messages to the operation panel 180 via the first connector C1 and the eighth connector C8.

[0119] Next, a method for attaching and detaching the main board 110 will be described.

[0120] As shown in Figure 6, the main board 110 and the connector board 120 are detachably housed in the main body housing 10. Here, the main body housing 10 has a metal plate 10B and rails RA. The metal plate 10B is a metal plate and extends in a direction perpendicular to the first direction. The rails RA are disposed on the upper and lower parts of the metal plate 10B. The rails RA can guide the main board 110 so that it can slide back and forth.

[0121] The connector board 120 is fixed to the main body housing 10. Specifically, the connector board 120 is fixed to the metal plate 10B with four screws N. When removing the connector board 120, the four screws N are removed to remove the connector board 120 from the metal plate 10B.

[0122] The main board 110 is fixed to the main housing 10. The main board 110 is held at its upper and lower ends by rails RA so as to be unable to move in the vertical direction. The main connector CM is connected to the first connector C1 of the connector board 120, so that the main board 110 is held so as not to move in the second direction.

[0123] 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.

[0124] 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 connector board 120, allowing the main board 110 to move in the second direction along the rail RA. This allows the main board 110 to be pulled out to one side in the second direction, for example, backward.

[0125] 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 rails RA, and the main board 110 is pushed forward along the rails RA. As a result, the main connector CM of the main board 110 faces the first connector C1 of the connector board 120, and by pushing the main board 110 further forward, the main connector CM is connected to the first connector C1.

[0126] 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).

[0127] When the main board 110 is attached to the main housing 10 from the state shown in FIG. 9B, the main board 110 is disposed inside the enclosure EN as shown in FIG. 9A.

[0128] As a result of the above, the present embodiment can achieve the following effects: According to the image forming apparatus 1, when replacing the main board 110 on which the ASIC 111 is arranged, it is sufficient to disconnect the main connector CM of the main board 110 from the first connector C1 of the connector board 120. Therefore, when replacing the main board 110, it is not necessary to disconnect the terminals of the first harness H1, second harness H2, third harness H3, fourth harness H4, fifth harness H5, sixth harness H6, and seventh harness H7 that connect the main motor 160, making it easy to replace the ASIC 111.

[0129] Furthermore, by consolidating the power supplied from the low-voltage power supply board 140 once on the connector board 120, there is no need to connect the low-voltage power supply board 140 to each component, and it is possible to reduce the harness connected to the low-voltage power supply board 140. This makes it easier to replace the low-voltage power supply board 140.

[0130] Furthermore, since the main motor drive circuit 112 is disposed on the main board 110, the main motor drive circuit 112 can be easily replaced by replacing the main board 110.

[0131] Furthermore, since the polygon motor drive circuit 113 is disposed on the main board 110, the polygon motor drive circuit 113 can be easily replaced by replacing the main board 110.

[0132] Furthermore, since the connector board 120 is provided with a fifth connector C5 to which a terminal of the fourth harness H4 that connects the high-voltage power supply board 150 is connected, there is no need to disconnect the terminal of the fourth harness H4 when replacing the main board 110 on which the ASIC 111 is mounted. This makes it possible to reduce the number of harnesses that connect the low-voltage power supply board 140 and the high-voltage power supply board 150. When replacing the low-voltage power supply board 140, it is only necessary to disconnect the third harness H3 that connects to the connector board 120, making it easier to replace the low-voltage power supply board 140.

[0133] Furthermore, since the connector board 120 is provided with a sixth connector C6 to which a terminal of the fifth harness H5 that connects the electric clutch 170 is connected, there is no need to disconnect the terminal of the fifth harness H5 when replacing the main board 110 on which the ASIC 111 is mounted. This makes it possible to reduce the number of harnesses connecting the low-voltage power supply board 140 and the high-voltage power supply board 150. When replacing the low-voltage power supply board 140, it is only necessary to disconnect the third harness H3 that connects to the connector board 120, making it easier to replace the low-voltage power supply board 140.

[0134] Furthermore, the electric clutch 170 is supplied with the first DC voltage without passing through the main board 110. This simplifies the wiring of the connector board 120. Furthermore, the number of terminals on the connector board 120 can be reduced.

[0135] Furthermore, the connector board 120 is provided with a seventh connector C7 for connecting the wireless communication module 131. Therefore, when replacing the main board 110 on which the ASIC 111 is mounted, there is no need to disconnect the seventh connector C7. Furthermore, the wireless communication module 131 is connected directly to the seventh connector C7 without using a harness. Therefore, the number of harnesses can be reduced.

[0136] The connector board 120 is also provided with an eighth connector C8 that connects to the operation panel 180. Therefore, when replacing the main board 110 on which the ASIC 111 is arranged, it is not necessary to detach the eighth connector C8.

[0137] The first connector C1 also has a power connector C11 and a signal connector C12. For this reason, the power connector C11 is configured to have as many terminals as possible for sending power as possible, and the signal connector C12 is configured to have as many terminals as possible for sending digital signals as possible. As a result, it is possible to reduce the amount of electromagnetic wave shielding disposed between the power and signal paths in the first connector C1, making it possible to make the entire first connector C1 compact.

[0138] Furthermore, the main board 110, the connector board 120, and the main motor 160 are all disposed in the first region RE1, which allows the harnesses connecting the main board 110, the connector board 120, and the main motor 160 to be shortened.

[0139] Furthermore, in the second direction, the connector board 120 is located between the main board 110 and the main motor 160. Therefore, the first harness H1 connecting the connector board 120 and the main motor 160 can be shortened.

[0140] Furthermore, since the main board 110 is attached to and detached from the connector board 120 in the second direction, no large opening is required when attaching and detaching the main board 110 .

[0141] Furthermore, the low-voltage power supply board 140 is located in the second region RE2. This prevents the main board 110 and the connector board 120 from interfering with the low-voltage power supply board 140. Furthermore, because the low-voltage power supply board 140 overlaps with the connector board 120 when viewed from the first direction, the third harness H3 connecting the low-voltage power supply board 140 and the connector board 120 can be shortened.

[0142] Furthermore, when the main board 110 is attached to the main housing 10, the main board 110 is placed inside the enclosure EN, so that the main board 110 can be isolated from other components and protected.

[0143] Although the embodiment has been described above, the image forming apparatus 1 can be modified as appropriate as exemplified below.

[0144] In the above-described embodiment, the pickup roller 33 is exemplified as an example of the conveying roller, but the conveying roller may be another sheet conveying roller such as a registration roller or a discharge roller 81 .

[0145] In the above-described embodiment, the main board 110 and the connector board 120 are directly connected to each other by the main connector CM and the first connector C1, which are board-to-board connectors, without using a harness. However, they may be connected to each other via a harness. If the main board 110 and the connector board 120 are connected to each other via a harness, the main board 110 can be removed by first disconnecting the harness terminals.

[0146] In the above-described embodiment, the main connector CM of the main board 110 and the first connector C1 of the connector 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.

[0147] In the above-described embodiment, the first connector C1 has two connectors, a power connector C11 and a signal connector C12 (see FIG. 3), but the first connector C1 may also be configured as a single connector, as shown in FIG. 11.

[0148] In the above-described embodiment, the enclosure EN is fixed to the main housing 10 (see FIGS. 9( a) and 9(b)), but the enclosure EN may be detachable from the main housing 10 together with the main board 110. For example, in the configuration shown in FIGS. 10(a) and 10(b), the main board 110 is fixed to the enclosure EN, and the enclosure EN is detachable from the main housing 10. In this configuration, as shown in FIG. 10(b), to remove the main board 110 from the main housing 10, it is sufficient to remove the enclosure EN. In this configuration, the user can replace the main board 110 without touching it.

[0149] 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.

[0150] In the above-described embodiment, the main motor drives the image forming unit and the conveying unit, but the main motor may be configured to drive the image forming unit without driving the conveying unit, or may be configured to drive the conveying unit without driving the image forming unit.Furthermore, the main motor may be configured to drive part of the image forming unit without driving the conveying unit, or part of the conveying unit without driving the image forming unit.

[0151] In the above-described embodiment, the main motor drive circuit 112 and the polygon motor drive circuit 113 are arranged on the main board 110, but it is also possible to configure at least one of the main motor drive circuit 112 and the polygon motor drive circuit 113 to be arranged on the connector board 120.

[0152] 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.

[0153] 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.

[0154] The elements described in the embodiments and modifications may be implemented in any combination.

[0155] REFERENCE SIGNS LIST 1 Image forming apparatus 10 Main housing 50 Exposure unit 110 Main board 111 ASIC 120 Connector board 160 Main motor C1 First connector C2 Second connector C3 Third connector H1 First harness H2 Second harness

Claims

1. An image forming apparatus comprising: a main body housing; an image forming unit having a photosensitive drum; a main motor that provides driving force to the image forming unit; a main board that is detachably housed in the main body housing and on which an ASIC that controls the main motor is arranged; and a connector board having a first connector and a second connector, the main board is directly connected to the first connector without via a harness, and a terminal of a first harness that connects the main motor is connected to the second connector, wherein the ASIC sends a control signal to the main motor via the first connector and the second connector.

2. The image forming apparatus described in claim 1, characterized in that the image forming unit further includes an exposure unit that exposes the photosensitive drum, the connector board further includes a third connector to which a terminal of a second harness that connects the exposure unit is connected, and the ASIC transmits a control signal to the exposure unit via the first connector and the third connector.

3. An image forming apparatus as described in claim 1, further comprising a low-voltage power supply board on which an AC / DC converter is arranged to convert AC voltage supplied from a commercial power source into DC voltage of a first voltage, and wherein the connector board is arranged with a fourth connector to which a terminal of a third harness that connects the low-voltage power supply board is connected.

4. An image forming apparatus as described in claim 3, characterized in that the main board further has a main motor drive circuit arranged thereon that outputs drive power to the main motor, and the main motor drive circuit is supplied with a first DC voltage from the AC / DC converter via the fourth connector and the first connector, and outputs drive power to the main motor based on a control signal sent from the ASIC.

5. 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 to a sheet together with the photosensitive drum, wherein the ASIC controls the voltages applied to the developing roller, the charger, and the transfer roller.

6. The image forming apparatus according to claim 3, wherein the image forming section further comprises 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 main board further having a polygon motor drive circuit that outputs drive power to the polygon motor, the polygon motor drive circuit being supplied with a first DC voltage from the AC / DC converter via the fourth connector and the first connector, and outputting drive power to the polygon motor based on a control signal sent from the ASIC via the first connector and the third connector.

7. An image forming apparatus as described in claim 5, further comprising a high-voltage power supply board on which a charging voltage application circuit that applies a charging voltage to the charger, a developing voltage application circuit that applies a developing voltage to the developing 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 connector board via a fourth harness, the connector board having a fifth connector to which a terminal of the fourth harness is connected, the charging voltage application circuit outputs the charging voltage based on a control signal sent from the ASIC via the first connector and the fifth connector, the developing voltage application circuit outputs the developing voltage based on a control signal sent from the ASIC via the first connector and the fifth connector, and the transfer voltage application circuit outputs the transfer voltage based on a control signal sent from the ASIC via the first connector and the fifth connector.

8. An image forming apparatus as described in claim 3, further comprising a conveying roller that receives driving force from the main motor to convey a sheet, and an electric clutch that can be switched between a transmission state in which the driving force from the main motor is transmitted to the conveying roller and a cut-off state in which the driving force from the main motor is not transmitted to the conveying roller, wherein the connector board has a sixth connector, and a terminal of a fifth harness that connects the electric clutch is connected to the sixth connector, and the electric clutch can be switched between the transmission state and the cut-off state based on a control signal sent from the ASIC via the first connector and the sixth connector.

9. The image forming apparatus according to claim 8, wherein the transport rollers include a pickup roller that feeds the sheet stored in the sheet tray toward the photosensitive drum.

10. An image forming apparatus as described in claim 8, wherein the electric clutch is supplied with the first voltage DC voltage from the low-voltage power supply board via the fourth connector and the sixth connector, without passing through the first connector.

11. An image forming apparatus as described in claim 1, further comprising a wireless communication module capable of performing wireless communication, wherein the connector board is provided with a seventh connector to which the wireless communication module is directly connected without a harness, and wherein the ASIC performs wireless communication with the wireless communication module via the first connector and the seventh connector.

12. An image forming apparatus as described in claim 1, further comprising an operation panel, wherein the connector board has an eighth connector, to which a terminal of a sixth harness that connects the operation panel is connected, and wherein the ASIC receives commands input to the operation panel via the eighth connector and the first connector.

13. The image forming apparatus described in claim 4, characterized in that the image forming section further comprises an exposure unit that exposes the photosensitive drum, the first connector comprises a power connector having a terminal for sending power and a signal connector having a terminal for sending control signals without sending power, the power connector having a terminal for outputting drive power from the main board to the main motor, and the signal connector having a terminal for outputting control signals for controlling the exposure unit from the main board.

14. The image forming apparatus described in claim 3, characterized in that the photosensitive drum is rotatable around a rotation axis extending in a first direction, 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 connector board and the main motor are all arranged in the first region.

15. The image forming apparatus according to claim 14, wherein the connector board is located between the main board and the main motor in the vertical direction and in a second direction perpendicular to the first direction.

16. An image forming apparatus according to claim 15, characterized in that the main board has a main connector that is detachable from the first connector in the second direction, and is detachable from the connector board in the second direction.

17. An image forming apparatus as described in claim 15, further comprising a low-voltage power supply board on which an AC / DC converter is arranged that converts AC voltage supplied from a commercial power source into DC voltage of a first voltage, the low-voltage power supply board being located in the second area, and the low-voltage power supply board overlapping the connector board when viewed from the first direction.

18. The image forming apparatus described in claim 17, characterized in that the connector board is located above and below the rotation axis of the photosensitive drum and on one side of a second direction perpendicular to the first direction, and the third harness passes through the one side of the rotation axis of the photosensitive drum in the second direction and extends from the first area to the second area.

19. An image forming apparatus as described in claim 18, further comprising a pickup roller that receives driving force from the main motor and feeds sheets stored in a sheet tray toward a photosensitive drum, and an electric clutch that can be switched between a transmission state in which the driving force from the main motor is transmitted to the pickup roller and a cut-off state in which the driving force from the main motor is not transmitted to the pickup roller, wherein the electric clutch is disposed in the first region, and the main motor is located between the connector board and the electric clutch in the second direction.

20. An image forming apparatus as described in claim 14, further comprising a high-voltage power supply board on which a charging voltage application circuit that applies a charging voltage to a charger, a development voltage application circuit that applies a development voltage to a development roller, and a transfer voltage application circuit that applies a transfer voltage to a transfer roller are arranged, the high-voltage power supply board being connected to the connector board via a fourth harness, the high-voltage power supply board being arranged in the second area.

Images