Image forming apparatus

Abstract

To provide an image forming apparatus that can reduce the effects of noise. [Solution] The image forming apparatus 1 comprises a main body housing 2 having a first side surface 21 and a second side surface 22, a photosensitive drum 53 rotatable with respect to a rotation axis X, a toner cartridge 55 having a memory 56 including a memory contact 56a, a main body contact 72a that can contact the memory contact 56a, a motor 71 that drives the photosensitive drum 53, a main board 81 that controls the motor 71, and a first relay board 82 connected to the main board 81. The main body contact 72a and the motor 71 are located closer to the first side surface 21 than to the second side surface 22 in the left-right direction, the main board 81 is located closer to the second side surface 22 than to the first side surface 21 in the left-right direction, the first relay board 82 and the main board 81 are connected by a first wiring 91, the main body contact 72a and the first relay board 82 are connected by a second wiring 92, and the motor 71 and the first relay board 82 are connected by a third wiring 93.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1, there is known an image forming apparatus including a main body housing that houses an image forming unit for forming an image on a sheet, a left main body frame located on the left side of the image forming unit in the main body housing, and a right main body frame located on the right side of the image forming unit in the main body housing.

[0003] In such an image forming apparatus, a motor is provided on the left main body frame, and a main board is provided on the right main body frame.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an image forming apparatus, when a plurality of electrical components such as a motor that transmits signals to and from a main board are arranged on a left main body frame on the side opposite to the right main body frame where the main board is provided, the length and number of wirings for connecting the main board and the plurality of electrical components increase.

[0006] When the length and number of wirings increase, there is a risk that the influence of noise on the wirings increases, such as being more likely to pick up surrounding electromagnetic waves or the signal quality deteriorating.

[0007] Therefore, the present invention provides an image forming apparatus capable of reducing the influence of noise.

Means for Solving the Problems

[0008] The image forming apparatus that solves the above problems has the following features.

[0009] That is, the image forming apparatus comprises a main body housing having a first side and a second side arranged apart along a first direction, a photosensitive drum rotatable with respect to a rotation axis extending in the first direction, a toner cartridge containing toner for supplying to the photosensitive drum and having memory including memory contacts, a main body contact that can contact the memory contacts, a motor for driving the photosensitive drum, a main board for controlling the operation of the motor, and a first relay board connected to the main board, wherein the main body contact and the motor are located closer to the first side than the second side in the first direction, the main board is located closer to the second side than the first side in the first direction, the first relay board and the main board are connected by a first wiring capable of transmitting signals, the main body contact and the first relay board are connected by a second wiring capable of transmitting signals, and the motor and the first relay board are connected by a third wiring capable of transmitting signals.

[0010] This reduces the number of wires connecting the first relay board, to which the main contacts and motor are connected, to the main board, thereby reducing the overall length of the wires connecting the main contacts and motor to the main board and mitigating the effects of noise.

[0011] Furthermore, the main circuit board is positioned opposite the second side surface.

[0012] This allows the main board to be placed in a space-saving manner.

[0013] Furthermore, the main housing has a front surface located on the front side in the front-to-back direction perpendicular to the first direction, and the first relay board is positioned in front of the photosensitive drum and facing the front surface.

[0014] This allows users to access the first relay board more easily.

[0015] Furthermore, the first relay substrate is located closer to the first side surface than the second side surface in the first direction.

[0016] This allows for shorter second wiring connections between the main unit contacts and the first relay board, and shorter third wiring connections between the motor and the first relay board.

[0017] Furthermore, the device includes a sheet storage section for storing sheets that are transported toward the photosensitive drum, and the motor and the first relay board are located above the sheet storage section.

[0018] This allows the third wiring connecting the motor and the first relay board to be shortened.

[0019] Furthermore, the main board, the first relay board, and the main body contacts are arranged in order from top to bottom.

[0020] This makes it possible to shorten the first wiring connecting the first relay board and the main board, and the second wiring connecting the main contacts and the first relay board.

[0021] Furthermore, the first relay board has a mounting surface on which a connector portion is arranged to connect the main body contacts and the motor, and is located in front of the main body contacts and the motor in the front-to-back direction perpendicular to the first direction, with the mounting surface of the first relay board facing rearward.

[0022] This allows for shorter second wiring connections between the main unit contacts and the first relay board, and shorter third wiring connections between the motor and the first relay board.

[0023] Furthermore, the main body contacts are located in front of the photosensitive drum.

[0024] This allows the second wiring connecting the main unit contacts and the first relay board to be shortened.

[0025] Furthermore, it includes a main connector having the main body contact point and a harness connection portion to which the second wiring is connected. The main body contact point faces rearward, and the harness connection portion is located forward of the main body contact point.

[0026] Thereby, the second wiring connecting the main body contact point and the first relay board can be shortened.

[0027] Moreover, the first relay board has a photosensor for detecting the rotation amount of the motor.

[0028] Thereby, the wiring connecting the photosensor and the first relay board can be reduced.

[0029] It further includes a sheet sensor for detecting the size of the sheet conveyed toward the photosensitive drum. The sheet sensor is located closer to the first side surface than the second side surface in the first direction. The sheet sensor and the first relay board are connected by a fourth wiring capable of signal transmission.

[0030] Thereby, the length of the wiring for connecting the sheet sensor and the main board can be shortened.

[0031] It further includes a sheet storage portion for storing the sheet conveyed toward the photosensitive drum, a paper feed roller for feeding the sheet stored in the sheet storage portion, and a solenoid for switching the drive of the paper feed roller. The paper feed roller is located rearward of the motor in the front-rear direction orthogonal to the first direction. The solenoid and the first relay board are connected by a fifth wiring capable of signal transmission.

[0032] Thereby, the length of the wiring for connecting the solenoid and the main board can be shortened.

[0033] Furthermore, the main housing has a rear surface located on the rear side in a front-to-back direction perpendicular to the first direction, and further comprises a paper discharge sensor located behind the photosensitive drum for detecting sheets discharged from the main housing, and a second relay board located behind the photosensitive drum and facing the rear surface, wherein the second relay board and the main board are connected by a sixth wiring capable of transmitting signals, and the paper discharge sensor and the second relay board are connected by a seventh wiring capable of transmitting signals.

[0034] This allows for a shorter wiring length to connect the paper output sensor and the main board.

[0035] Furthermore, the device includes a high-voltage board connected to the main board by an eighth wiring capable of transmitting signals, and a low-voltage board connected to the main board by a ninth wiring capable of transmitting signals, wherein the high-voltage board and the low-voltage board are located closer to the second side surface than to the first side surface in the first direction.

[0036] This allows for shortening the eighth wiring that connects the high-voltage board to the main board, and the ninth wiring that connects the low-voltage board to the main board.

[0037] Furthermore, the first relay substrate is positioned in the first direction at a location closer to the first side surface than the second side surface, and facing the first side surface.

[0038] This allows for shorter second wiring connections between the main unit contacts and the first relay board, and shorter third wiring connections between the motor and the first relay board. [Effects of the Invention]

[0039] According to the present invention, the number of wires connecting the first relay board, to which the main contacts and motor are connected, to the main board can be reduced, thereby reducing the overall length of the wires connecting the main contacts and motor to the main board. This makes it possible to reduce the effects of noise. [Brief explanation of the drawing]

[0040] [Figure 1] This is a central cross-sectional view showing an image forming apparatus. [Figure 2] This is a left front perspective view showing an image forming apparatus. [Figure 3] This is a right front perspective view showing an image forming apparatus. [Figure 4] This is a rear right perspective view showing an image forming apparatus. [Figure 5] This is a perspective view showing the process cartridge. [Figure 6] This is a wiring diagram for electrical components. [Figure 7] This is a left side view showing the inside of the main unit's casing. [Figure 8] This is a left-side cross-sectional view showing the inside of the main unit's casing. [Figure 9] This is a front view showing the inside of the main unit's casing. [Figure 10] This is a right-side view showing the inside of the main unit's casing. [Figure 11] This is a plan cross-sectional view showing a motor and a first relay board supported by a motor case. [Figure 12] This is a right-side cross-sectional view showing a rotary encoder, which consists of a rotating disk fixed to a motor and a photosensor mounted on a first relay board. [Figure 13] This is a left side cross-sectional view showing the main body connector supported by the first main body frame 25. [Figure 14] This is a rear view showing the inside of the main unit's casing. [Figure 15] This is a left front perspective view showing a modified example of the placement of the first relay board. [Modes for carrying out the invention]

[0041] Next, embodiments for carrying out the present invention will be described with reference to the attached drawings.

[0042] [Image forming apparatus] The image forming apparatus 1 shown in Figure 1 is one embodiment of the image forming apparatus according to the present invention, and is a laser printer that forms an image on a sheet S using an electrophotographic method.

[0043] In the following explanation, the right side of Figure 1 is defined as the front side of the image forming apparatus 1, the left side of Figure 1 is defined as the rear side of the image forming apparatus 1, the front of the page in Figure 1 is defined as the left side of the image forming apparatus 1, and the back of the page in Figure 1 is defined as the right side of the image forming apparatus 1. Furthermore, the top and bottom sides of Figure 1 are defined as the top and bottom sides of the image forming apparatus 1, respectively.

[0044] The image forming apparatus 1 comprises a main housing 2, a paper feeding unit 3, an image forming unit 5, a fuser 60, and a paper discharge unit 65. The main housing 2 houses the paper feeding unit 3, the image forming unit 5, the fuser 60, and the paper discharge unit 65.

[0045] An opening 2A is provided at the front upper part of the main housing 2, and the main housing 2 has a top cover 20 that can open and close the opening 2A. The top cover 20 is located at the rear end of the top cover 20 and is configured to be rotatable around a pivot shaft 20a that extends in the left-right direction. By rotating around the pivot shaft 20a, the top cover 20 can move between a closed position that closes the opening 2A and an open position that opens the opening 2A.

[0046] The paper feeding unit 3 comprises a sheet tray 10 for storing sheets S and a sheet transport unit 30. The paper feeding unit 3 is located at the bottom of the main body housing 2 and transports the sheets S stored in the sheet tray 10 to the image forming unit 5. The image forming apparatus 1 has a transport path P for sheets S from the paper feeding unit 3 through the image forming unit 5 to the paper discharge unit 65. The sheet tray 10 is an example of a sheet storage unit that stores sheets that are transported toward the photosensitive drum.

[0047] The sheet transport unit 30 is a transport mechanism that separates and removes the sheets S contained in the sheet tray 10 one by one and transports them toward the image forming unit 5, and is equipped with a paper feed roller 31, a separation roller 32, a separation pad 33, and a transport roller 34.

[0048] The paper feed roller 31 is a roller for feeding sheets S, which are stored in the sheet tray 10, toward the separation roller 32. The separation roller 32 is located downstream of the paper feed roller 31 in the sheet transport direction, and the separation pad 33 is positioned opposite the separation roller 32 and is biased toward the separation roller 32.

[0049] The sheets S, fed towards the separation roller 32 by the paper feed roller 31, are separated one by one between the separation roller 32 and the separation pad 33. The separated sheets S are then fed to the transport path P by the transport roller 34. The sheets S fed to the transport path P are transported towards the image forming unit 5.

[0050] The image forming unit 5 is located downstream of the paper feeding unit 3 in the sheet transport direction and forms an image on the sheet S transported from the paper feeding unit 3. The image forming unit 5 includes a process cartridge 50 that transfers an image to the surface of the sheet S transported from the paper feeding unit 3, and an exposure unit 41 that exposes the surface of the photosensitive drum 53 of the process cartridge 50.

[0051] The process cartridge 50 is detachably mounted in the main unit housing 2. The process cartridge 50 comprises a drum unit 51 and a toner cartridge 55, and the toner cartridge 55 is mounted in the drum unit 51 before being mounted in the main unit housing 2. The process cartridge 50 mounted in the main unit housing 2 is positioned above the paper feed section 3 in the main unit housing 2.

[0052] The drum unit 51 includes a photosensitive drum 53, a charger 54, and a transfer roller 42. The toner cartridge 55 includes a toner storage chamber 57, a supply roller 58, and a developer roller 59.

[0053] The opening 2A of the main housing 2 is configured to allow the process cartridge 50 to pass through, and by moving the top cover 20 to the open position, the process cartridge 50 can be attached to and detached from the main housing 2 through the opening 2A. The process cartridge 50 installed in the main housing 2 can be removed from the main housing 2, for example, when the process cartridge 50 needs to be replaced, or when the sheet S jams around the photosensitive drum 53 and transfer roller 42.

[0054] When the process cartridge 50 is mounted in the main housing 2, the photosensitive drum 53 is positioned such that its rotation axis X extends along the left-right direction. The photosensitive drum 53 rotates about its rotation axis X. In other words, the photosensitive drum 53 is rotatable with respect to its rotation axis X. The left-right direction is one example of a first direction.

[0055] When the process cartridge 50 is mounted in the main housing 2, the developing roller 59 is positioned such that its rotation axis Y extends along the left-right direction. The developing roller 59 rotates about its rotation axis Y. In other words, the developing roller 59 is rotatable with respect to its rotation axis Y. The rotation axis Y of the developing roller 59 is positioned parallel to the rotation axis X of the photosensitive drum 53.

[0056] Furthermore, in the image forming apparatus, a drum unit 51 having a photosensitive drum 53 and a toner cartridge 55 having a developing roller 59 can be configured to be mounted separately in the main body housing 2.

[0057] The exposure unit 41 is equipped with a laser diode, a polygon mirror, a lens, and a reflector, and exposes the surface of the photosensitive drum 53 by irradiating the photosensitive drum 53 with laser light based on image data input to the image forming apparatus 1.

[0058] The toner storage chamber 57 contains toner to be supplied to the photosensitive drum 53. The toner stored in the toner storage chamber 57 is agitated by the agitator 571 and sent to the supply roller 58. The supply roller 58 then supplies the toner sent from the toner storage chamber 57 to the developing roller 59.

[0059] The developing roller 59 is positioned in close contact with the supply roller 58 and carries toner that is supplied from the supply roller 58 and has been positively charged by friction between the supply roller 58 and the developing roller 59. In addition, a developing bias is applied to the developing roller 59 by a bias application means (not shown).

[0060] The photosensitive drum 53 is positioned adjacent to the developing roller 59. The surface of the photosensitive drum 53 is uniformly charged by the charger 54 and then exposed by the exposure unit 41. The exposed portion of the photosensitive drum 53 has a lower potential than other portions, and an electrostatic latent image based on the image data is formed on the photosensitive drum 53. Then, positively charged toner is supplied from the developing roller 59 to the surface of the photosensitive drum 53 on which the electrostatic latent image has been formed, causing the electrostatic latent image to become visible and form a toner image.

[0061] The transfer roller 42 is positioned opposite the photosensitive drum 53, and a transfer bias is applied by a bias application means (not shown). With the transfer bias applied to the surface of the transfer roller 42, the sheet S is transported while being sandwiched between the photosensitive drum 53, on which the toner image has been formed, and the transfer roller 42, thereby transferring the toner image formed on the surface of the photosensitive drum 53 to the surface of the sheet S. The sheet S on which the toner image has been transferred is then transported to the fuser 60.

[0062] The fuser 60 includes a heating roller 61 and a pressure roller 62, and fixes the image transferred to the sheet S by the process cartridge 50. The heating roller 61 is heated by power supplied from the power supply of the image forming apparatus 1. The pressure roller 62 is positioned opposite the heating roller 61. One of the heating roller 61 and the pressure roller 62 is biased toward the other by a biasing mechanism (not shown), and the heating roller 61 and the pressure roller 62 are in close contact.

[0063] When the sheet S on which the toner image has been transferred is transported to the fuser unit 60, the sheet S is heated while being held between the heating roller 61 and the pressure roller 62, thereby fixing the toner image transferred to the sheet S as it is being transported. In this way, the fuser unit 60 fixes the toner image to the sheet S. The sheet S on which the toner has been fixed by the fuser unit 60 is then transported to the paper discharge unit 65.

[0064] The paper discharge section 65 is located downstream of the fuser 60 in the sheet transport direction and discharges the sheet S, on which an image has been formed in the image forming section 5, to the outside of the image forming apparatus 1. The paper discharge section 65 includes a pair of paper discharge rollers 66, a paper discharge tray 67, and an extension tray 68. The pair of paper discharge rollers 66, the paper discharge tray 67, and the extension tray 68 are provided on the top cover 20. The pair of paper discharge rollers 66 is configured to discharge the sheet S, which has been transported from the fuser 60 along the transport path P, toward the outside of the main housing 2. The paper discharge tray 67 supports the sheet S that has been discharged to the outside of the main housing 2 by the pair of paper discharge rollers 66.

[0065] The extension tray 68 is configured to rotate around a pivot center 68a. The extension tray 68 can move between a storage position where it is folded above the output tray 67 by rotating backward, and an extended position where it is extended in front of the output tray 67 by rotating forward. By moving to the extended position, the extension tray 68 can support the sheets S that have been ejected to the outside of the main housing 2 together with the output tray 67.

[0066] [Main unit] As shown in Figures 2 to 4, the main body housing 2 has a first side surface 21 and a second side surface 22 that are separated along the left-right direction. The first side surface 21 is the left side of the main body housing 2, and the second side surface 22 is the right side. The first side surface 21 extends in the front-rear and up-down directions and faces to the left. The second side surface 22 extends in the front-rear and up-down directions and faces to the right.

[0067] The main body housing 2 has a front surface 23 and a rear surface 24 that are separated along the front-rear direction. The front surface 23 is located on the front side of the main body housing 2 in the front-rear direction, and the rear surface 24 is located on the rear side of the main body housing 2 in the front-rear direction. The front surface 23 extends in the left-right and up-down directions and faces forward. The rear surface 24 extends in the left-right and up-down directions and faces rearward. The front-rear direction is an example of a direction perpendicular to the first direction.

[0068] [Main frame] As shown in Figures 2 to 4, a first main frame 25 and a second main frame 26 are arranged inside the main body housing 2, separated from each other along the left-right direction. The first main frame 25 is located at the left end of the main body housing 2, and the second main frame 26 is located at the right end of the main body housing 2. The first main frame 25 extends in the front-rear and up-down directions, and is positioned so that its plate surface faces the left-right direction. The second main frame 26 extends in the front-rear and up-down directions, and is positioned so that its plate surface faces the left-right direction.

[0069] The process cartridge 50 and fuser unit 60 are positioned between the first main frame 25 and the second main frame 26 in the left-right direction. The first main frame 25 is located to the left of the process cartridge 50 and fuser unit 60, and the second main frame 26 is located to the right of the process cartridge 50 and fuser unit 60.

[0070] [Toner Cartridge] As shown in Figure 5, the toner cartridge 55 has a memory 56. The memory 56 is located at the left end of the toner cartridge 55. The memory 56 is a storage medium that stores information about the toner cartridge 55. The memory 56 is composed of, for example, an IC chip.

[0071] Memory 56 stores, for example, identification information and lifespan information of the toner cartridge 55. The identification information is information for identifying the toner cartridge 55. For example, information regarding the serial number of the toner cartridge 55 can be used as identification information. The lifespan information is information representing the lifespan of the toner cartridge 55. For example, information regarding the cumulative rotation count of the toner cartridge 55 can be used as lifespan information.

[0072] The memory 56 includes a memory contact 56a, which is a conductive metal surface. The memory contact 56a is electrically connected to the memory element of the memory 56. The memory contact 56a faces forward and downward. The memory 56 is exposed to the outside from the process cartridge 50 when the toner cartridge 55 is installed in the drum unit 51.

[0073] [Electrical components for image forming machines] (Motor, main board, first relay board, photosensor, and main unit connector) As shown in Figures 1, 6 to 10, the image forming apparatus 1 includes, as electrical components, a motor 71, a main board 81, a first relay board 82, a photosensor 76, and a main connector 72.

[0074] The motor 71 is a drive source for driving the photosensitive drum 53. The motor 71 drives the rollers of the paper feeding unit 3, the image forming unit 5, the fuser 60, and the paper discharge unit 65. The motor 71 is supported by the first main frame 25 and is located closer to the first side surface 21 than to the second side surface 22 of the main housing 2 in the left-right direction. The motor 71 is located at the front and upper end of the first main frame 25. The motor 71 is located above the sheet tray 10.

[0075] The main board 81 is a board for controlling the operation of the motor 71. The motor 71 is connected to the main board 81, and signals can be transmitted between the main board 81 and the motor 71. For example, the motor 71 is driven by the control of the main board 81.

[0076] The main board 81 is supported on the right side of the second main frame 26. The main board 81 is located on the upper part of the second main frame 26. In the left-right direction, the main board 81 is located closer to the second side 22 of the main housing 2 than to the first side 21. The second side 22 of the main housing 2 is located to the right of the main board 81, and the main board 81 faces the second side 22 in the left-right direction.

[0077] The first relay board 82 is positioned between the main board 81 and the motor 71 and is connected to both the main board 81 and the motor 71. Signal transmission between the main board 81 and the motor 71 is performed via the first relay board 82.

[0078] The first relay board 82 is located at the front and upper end of the main housing 2, and is positioned in front of the photosensitive drum 53. The front surface 23 of the main housing 2 is located in front of the first relay board 82, and the first relay board 82 faces the front surface 23 in the front-to-back direction. In the left-to-right direction, the first relay board 82 is located closer to the first side surface 21 of the main housing 2 than to the second side surface 22. The first relay board 82 is located above the sheet tray 10.

[0079] As shown in Figures 11 and 12, the image forming apparatus 1 includes a motor case 27 that houses a motor 71. The motor case 27 is supported on the right side of the first main frame 25. The motor 71 is supported on the first main frame 25 via the motor case 27. The first relay board 82 is supported on the motor case 27 in front of the motor 71.

[0080] A rotating disk 711 with a slit 711a is fixed to the rotating shaft 71a of the motor 71. The rotating disk 711 can rotate integrally with the rotating shaft 71a. A photosensor 76 is mounted on the first relay board 82. The first relay board 82 has a mounting surface 82a facing the rear, and the photosensor 76 is mounted on the mounting surface 82a of the first relay board 82.

[0081] A rotary encoder is configured with a rotating disk 711 and a photosensor 76. By detecting the light transmitted through the slit 711a of the rotating disk 711 using the photosensor 76, it is possible to detect the amount of rotation of the motor 71. Thus, the first relay board 82 has a photosensor 76 for detecting the amount of rotation of the motor 71.

[0082] The photosensor 76 is connected to the main board 81, and signals can be transmitted between the photosensor 76 and the main board 81. For example, the amount of rotation of the motor 71 detected by the photosensor 76 is input to the main board 81.

[0083] As shown in Figure 8, the main unit connector 72 is supported by the first main unit frame 25. The main unit connector 72 is located in the center of the first main unit frame 25 in the front-to-back direction and at the bottom in the up-to-down direction. In the left-to-right direction, the main unit connector 72 is located closer to the first side surface 21 than to the second side surface 22 of the main unit housing 2. The main unit connector 72 is located in front of the photosensitive drum 53.

[0084] As shown in Figure 13, the main connector 72 has a main contact 72a that can contact the memory contact 56a of the memory 56. The main contact 72a is connected to the main board 81, and it is possible to transmit signals between the main contact 72a and the main board 81. For example, information stored in the memory 56 is input to the main board 81 through the main contact 72a that contacts the memory contact 56a.

[0085] The main unit contact 72a contacts the memory contact 56a of the toner cartridge 55 when the toner cartridge 55 is installed in the main unit housing 2. The main unit contact 72a is a pin member that protrudes rearward and upward. In other words, the main unit contact 72a faces rearward and upward.

[0086] The first relay board 82 and the main board 81 are connected by a first wiring 91 that allows signal transmission. For example, a flat cable or harness can be used as the first wiring 91.

[0087] The main contact 72a and the first relay board 82 are connected by a second wiring 92 that allows signal transmission. For example, a cable or harness can be used as the second wiring 92. Signal transmission between the main contact 72a and the main board 81 is performed via the second wiring 92, the first relay board 82, and the first wiring 91.

[0088] The second wiring 92 is connected to the main contact 72a within the main connector 72 and extends from the harness connection portion 72b of the main connector 72 to the outside of the main connector 72. The harness connection portion 72b is located at the lower end of the main connector 72 and in front of the main contact 72a. The second wiring 92 extends forward and downward from the harness connection portion 72b.

[0089] The motor 71 and the first relay board 82 are connected by a third wiring 93 that allows signal transmission. For example, a cable or harness can be used as the third wiring 93. Signal transmission between the motor 71 and the main board 81 is performed via the third wiring 93, the first relay board 82, and the first wiring 91.

[0090] A connector section 821 is located on the mounting surface 82a of the first relay board 82, and the second wiring 92 and the third wiring 93 are connected to the first relay board 82 at the connector section 821. The connector section 821 is located at the upper end of the mounting surface 82a, and the second wiring 92 and the third wiring 93 are connected to the connector section 821 from above the first relay board 82. In other words, the motor 71 and the main body connector 72 are connected to the connector section 821. The first relay board 82 is located in front of the motor 71 and the main body connector 72 in the front-to-back direction.

[0091] In the image forming apparatus 1, several electrical components, such as a motor 71 and a main body connector 72 that transmit signals to the main board 81, are arranged on the first main body frame 25, which is on the opposite side of the second main body frame 26 on which the main board 81 is provided.

[0092] Here, if we were to attempt to connect the main contact 72a and the motor 71 to the main board 81 directly without going through the first relay board 82, it would be necessary to connect the main contact 72a and the main board 81, and the motor 71 and the main board 81, with separate wiring over their entire ranges.

[0093] However, by connecting the main contact 72a and motor 71 to the main board 81 via the first relay board 82, it becomes possible to connect the first relay board 82 and the main board 81 with a single first wire 91. Therefore, the number of wires connecting the first relay board 82 to which the main contact 72a and motor 71 are connected and the main board 81 can be reduced, and the overall length of the wires connecting the main contact 72a and motor 71 to the main board 81 can be reduced. This makes it possible to reduce the impact of noise on the main board 81.

[0094] In this case, since the first relay board 82 is located closer to the first side surface 21 than to the second side surface 22 in the left-right direction, the second wiring 92 connecting the main body contact 72a and the first relay board 82, and the third wiring 93 connecting the motor 71 and the first relay board 82 can be shortened.

[0095] Furthermore, since both the motor 71 and the first relay board 82 are located above the seat tray 10, and their heights are close together, the third wiring 93 connecting the motor 71 and the first relay board 82 can be shortened.

[0096] Furthermore, in the image forming apparatus 1, the main board 81, the first relay board 82, and the main contact 72a are arranged in order from top to bottom, so the first wiring 91 connecting the first relay board 82 and the main board 81, and the second wiring 92 connecting the main contact 72a and the first relay board 82 can be shortened.

[0097] Furthermore, since the main board 81 is positioned opposite the second side surface 22 of the main body housing 2, it is possible to position the main board 81 in a space-saving manner.

[0098] Furthermore, since the first relay board 82 is positioned in front of the photosensitive drum 53 and facing the front surface 23 of the main housing 2, it is possible to easily access the first relay board 82 when a user accesses the image forming apparatus 1 from the front to replace the first relay board 82.

[0099] Furthermore, since the main contact 72a is located in front of the photosensitive drum 53, the front-to-back position of the main contact 72a and the first relay board 82 can be brought closer together, and the second wiring 92 connecting the main contact 72a and the first relay board 82 can be shortened.

[0100] Furthermore, in the main unit connector 72, the main unit contact 72a faces rearward, and the harness connection portion 72b is located in front of the main unit contact 72a, so the second wiring 92 connecting the main unit contact 72a and the first relay board 82 can be shortened.

[0101] Furthermore, since the first relay board 82 is located in front of the main contact 72a and the motor 71, and the mounting surface 82a on which the connector portion 821 is placed faces backward, the second wiring 92 connecting the main contact 72a and the first relay board 82, and the third wiring 93 connecting the motor 71 and the first relay board 82 can be shortened.

[0102] Furthermore, since the photosensor 76 is directly mounted on the first relay board 82, it is possible to reduce the amount of wiring required to connect the photosensor 76 and the first relay board 82.

[0103] (Sheet sensor) As shown in Figures 1, 6, 7, and 9, the image forming apparatus 1 is equipped with a sheet sensor 73 as an electrical component. The sheet sensor 73 is a sensor for detecting the size of the sheet S that is housed in the sheet tray 10 and transported toward the photosensitive drum 53.

[0104] The sheet sensor 73 is connected to the main board 81, and signals can be transmitted between the sheet sensor 73 and the main board 81. For example, the size of the sheet S detected by the sheet sensor 73 is input to the main board 81.

[0105] The sheet sensor 73 is supported by the first main frame 25 and is located closer to the first side surface 21 than to the second side surface 22 of the main housing 2 in the left-right direction. The sheet sensor 73 is located in front of the main contact 72a.

[0106] As shown in Figure 9, the sheet tray 10 has side guides 11 that guide the left and right edges of the sheet S housed in the sheet tray 10. The side guides 11 are located at the left end of the main housing 2 and are configured to be movable along the left and right directions. In this case, the sheet sensor 73 can detect the left and right size of the sheet S according to the left and right position of the side guides 11.

[0107] The sheet sensor 73 and the first relay board 82 are connected by a fourth wiring 94 that allows signal transmission. Signal transmission between the sheet sensor 73 and the main board 81 is performed via the fourth wiring 94, the first relay board 82, and the first wiring 91.

[0108] If we were to attempt to connect the sheet sensor 73 and the main board 81 directly without going through the first relay board 82, it would be necessary to connect dedicated wiring to connect the sheet sensor 73 to the main board 81 over the entire area between the sheet sensor 73 and the main board 81.

[0109] However, by connecting the sheet sensor 73 and the main board 81 via the first relay board 82, the only dedicated wiring required to connect the sheet sensor 73 to the main board 81 is the fourth wiring 94 connecting the sheet sensor 73 and the first relay board 82. This allows the overall length of the wiring connecting the sheet sensor 73 and the main board 81 to be shortened.

[0110] (Solenoid) As shown in Figures 1, 6, and 7, the image forming apparatus 1 is equipped with a solenoid 74 as an electrical component. The solenoid 74 is configured to switch whether or not to transmit the driving force of the motor 71 to the paper feed roller 31.

[0111] In the image forming apparatus 1, the paper feed roller 31 is located behind the motor 71 in the front-to-back direction. The sheets S contained in the sheet tray 10 are fed backward, then transported upward, and further transported forward to be discharged outside the main body housing 2. With this configuration, the transport path P of the sheets S from the sheet tray 10 through the image forming unit 5 to the paper discharge unit 65 is formed in a roughly C shape.

[0112] The solenoid 74 is connected to the main board 81, and signals can be transmitted between the solenoid 74 and the main board 81. For example, the solenoid 74 is driven by the control of the main board 81.

[0113] The solenoid 74 is supported by the first main frame 25 and is located closer to the first side surface 21 than to the second side surface 22 of the main housing 2 in the left-right direction. The solenoid 74 is located in front of the photosensitive drum 53. The solenoid 74 is located behind the motor 71.

[0114] The solenoid 74 and the first relay board 82 are connected by a fifth wiring 95 that allows signal transmission. Signal transmission between the solenoid 74 and the main board 81 is performed via the fifth wiring 95, the first relay board 82, and the first wiring 91.

[0115] If we were to attempt to connect the solenoid 74 and the main board 81 directly without going through the first relay board 82, it would be necessary to connect a dedicated wiring harness to connect the solenoid 74 to the main board 81, extending across the entire area between the solenoid 74 and the main board 81.

[0116] However, by connecting the solenoid 74 and the main board 81 via the first relay board 82, the only dedicated wiring required to connect the solenoid 74 to the main board 81 is the fifth wiring 95 connecting the solenoid 74 and the first relay board 82. This allows the overall length of the wiring connecting the solenoid 74 and the main board 81 to be shortened.

[0117] (Paper ejection sensor and second relay board) As shown in Figures 1, 6, 7, and 14, the image forming apparatus 1 includes a paper discharge sensor 75 and a second relay board 83 as electrical components.

[0118] The paper ejection sensor 75 is a sensor for detecting the sheet S ejected from the main body housing 2. The paper ejection sensor 75 is supported by the first main body frame 25 and is located closer to the first side surface 21 than to the second side surface 22 of the main body housing 2 in the left-right direction. The paper ejection sensor 75 is located at the rear end and upper end of the first main body frame 25 and is located behind the photosensitive drum 53.

[0119] The paper ejection sensor 75 is connected to the main board 81, and signals can be transmitted between the main board 81 and the paper ejection sensor 75. For example, the detection result from the paper ejection sensor 75 indicating that a sheet S has been ejected from the main housing 2 is input to the main board 81.

[0120] The second relay board 83 is positioned between the main board 81 and the paper discharge sensor 75, and is connected to both the main board 81 and the paper discharge sensor 75. Signal transmission between the main board 81 and the paper discharge sensor 75 is performed via the second relay board 83.

[0121] The second relay board 83 is located at the rear end of the main body housing 2 and is positioned behind the photosensitive drum 53. The second relay board 83 is positioned behind the photosensitive drum 53 and facing the rear surface 24 of the main body housing 2.

[0122] The second relay board 83 and the main board 81 are connected by a sixth wiring 96 that allows signal transmission. For example, a cable or harness can be used as the sixth wiring 96.

[0123] The paper discharge sensor 75 and the second relay board 83 are connected by a seventh wiring 97 that can transmit signals. For example, a cable or harness can be used as the seventh wiring 97. Signal transmission between the paper discharge sensor 75 and the main board 81 is performed via the seventh wiring 97, the second relay board 83, and the sixth wiring 96.

[0124] Since the paper output sensor 75 is located at the rear end of the main casing 2, if we were to connect the paper output sensor 75 to the first relay board 82 located at the front end of the main casing 2, the wiring connecting the paper output sensor 75 and the first relay board 82 would become long.

[0125] However, in the image forming apparatus 1, since the paper discharge sensor 75 is connected to the second relay board 83 which is located behind the photosensitive drum 53, the length of the seventh wiring 97 connecting the paper discharge sensor 75 and the second relay board 83 can be made shorter than the length of the wiring when the paper discharge sensor 75 is connected to the first relay board 82. As a result, the overall length of the wiring connecting the paper discharge sensor 75 and the main board 81 can be shortened.

[0126] (High-voltage substrates and low-voltage substrates) As shown in Figures 1, 6, and 10, the image forming apparatus 1 includes a high-voltage substrate 84 and a low-voltage substrate 85 as electrical components. The high-voltage substrate 84 is a substrate for generating high voltage, and the low-voltage substrate 85 is a substrate that constitutes a power supply circuit, etc.

[0127] The high-voltage board 84 and the low-voltage board 85 are connected to the main board 81, and signals can be transmitted between the main board 81 and the high-voltage board 84 and the low-voltage board 85. For example, the operation of the high-voltage board 84 and the low-voltage board 85 is controlled by the main board 81.

[0128] The high-voltage substrate 84 and the low-voltage substrate 85 are supported on the right side of the second main frame 26. In other words, the high-voltage substrate 84 and the low-voltage substrate 85 and the main substrate 81 are located on the same side of the second main frame 26.

[0129] The high-voltage substrate 84 is located below the main substrate 81, and the low-voltage substrate 85 is located below the high-voltage substrate 84. The upper end of the high-voltage substrate 84 and the lower end of the main substrate 81 overlap when viewed from the left-right direction, and the high-voltage substrate 84 is located to the right of the main substrate 81.

[0130] The high-voltage circuit board 84 and the low-voltage circuit board 85 are located closer to the second side 22 of the main housing 2 than to the first side 21 in the left-right direction. The second side 22 of the main housing 2 is located to the right of the high-voltage circuit board 84 and the low-voltage circuit board 85, and the high-voltage circuit board 84 and the low-voltage circuit board 85 face the second side 22 in the left-right direction.

[0131] The high-voltage board 84 and the main board 81 are connected by an eighth wiring 98 capable of transmitting signals. For example, a flat cable or harness can be used as the eighth wiring 98.

[0132] The low-voltage board 85 and the main board 81 are connected by a ninth wiring 99 capable of transmitting signals. For example, a flat cable or harness can be used as the ninth wiring 99.

[0133] Since the high-voltage board 84 and the low-voltage board 85 are located on the right side of the second main frame 26 on which the main board 81 is placed, it is possible to shorten the eighth wiring 98 connecting the high-voltage board 84 to the main board 81, and the ninth wiring 99 connecting the low-voltage board 85 to the main board 81.

[0134] [Modified example of the placement of the first relay board] The first relay board 82, which is positioned opposite the front surface 23 of the main body housing 2, can also be positioned as shown in Figure 15, as shown in the first relay board 82A.

[0135] The first relay board 82A is supported on the left side of the first main frame 25 and is located closer to the first side surface 21 than to the second side surface 22 of the main housing 2 in the left-right direction. The first relay board 82A is located at the front and upper end of the main housing 2. The first side surface 21 of the main housing 2 is located to the left of the first relay board 82A, and the first relay board 82A faces the first surface 21 in the left-right direction.

[0136] In this way, by positioning the first relay board 82A closer to the first side surface 21 than the second side surface 22 and facing the first surface 21, the distance between the first relay board 82A and the main body contact 72a and motor 71 can be shortened compared to when the first relay board 82 is positioned facing the front surface 23.

[0137] This makes it possible to shorten the second wiring 92 connecting the main body contact 72a and the first relay board 82A, and the third wiring 93 connecting the motor 71 and the first relay board 82A. [Explanation of symbols]

[0138] 1. Image forming apparatus 2 Main unit 10-seat tray 21 First aspect 22 Second aspect 23 Front 24 Rear 31 Paper feed roller 53 Photosensitive drum 55 Toner Cartridges 56 memory 56a Memory contact 71 Motor 72 Main unit connector 72a Main body contact 72b Harness connection section 73. Sheet Sensor 74 Solenoid 75 Paper output sensor 76 Photosensor 81 Main board 82, 82A First relay board 82a Mounting surface 83 Second relay board 84 High-voltage substrate 85 Low-voltage substrate 91 1st wiring 92 2nd wiring 93 3rd wiring 94 4th wiring 95 5th wiring 96 6th wiring 97 7th wiring 98 8th wiring 99 9th wiring 821 Connector section S Seat X (rotation axis of the photosensitive drum)

Claims

1. A main body housing having a first side and a second side arranged apart along a first direction, A photosensitive drum rotatable with respect to a rotation axis extending in the first direction, A toner cartridge containing toner for supplying to the photosensitive drum and having memory including memory contacts, The main body contacts that can contact the aforementioned memory contacts, A motor that drives the photosensitive drum, A main board that controls the operation of the motor, It comprises a first relay board connected to the main board, The main body contact and the motor are located closer to the first side surface than to the second side surface in the first direction. The main substrate is located closer to the second side surface than to the first side surface in the first direction. The first relay board and the main board are connected by a first wiring that allows signal transmission. The main body contact and the first relay board are connected by a second wiring capable of transmitting signals. An image forming apparatus in which the motor and the first relay board are connected by a third wiring capable of transmitting signals.

2. The image forming apparatus according to claim 1, wherein the main substrate is arranged opposite to the second side surface.

3. The main housing has a front surface located on the front side in the front-rear direction perpendicular to the first direction, The image forming apparatus according to claim 1, wherein the first relay substrate is positioned in front of the photosensitive drum and facing the front surface.

4. The image forming apparatus according to claim 3, wherein the first relay substrate is located closer to the first side surface than the second side surface in the first direction.

5. The system further includes a sheet storage section for storing sheets that are transported toward the photosensitive drum, The image forming apparatus according to claim 4, wherein the motor and the first relay board are located above the sheet housing portion.

6. The image forming apparatus according to claim 1, wherein the main board, the first relay board, and the main body contacts are arranged in order from top to bottom.

7. The first relay board has a mounting surface on which a connector portion is arranged to connect the main body contacts and the motor, and is located in front of the main body contacts and the motor in the front-to-back direction perpendicular to the first direction. The image forming apparatus according to claim 1, wherein the mounting surface of the first relay substrate faces the rear.

8. The image forming apparatus according to claim 7, wherein the main body contact is located in front of the photosensitive drum.

9. The main body connector has the main body contacts and a harness connection portion to which the second wiring is connected, The aforementioned main body contact faces the rear, The image forming apparatus according to claim 8, wherein the harness connection portion is located in front of the main body contact.

10. The image forming apparatus according to claim 1, wherein the first relay board has a photosensor for detecting the amount of rotation of the motor.

11. The system further includes a sheet sensor that detects the size of the sheet being transported toward the photosensitive drum, The sheet sensor is located closer to the first side surface than the second side surface in the first direction. The image forming apparatus according to claim 1, wherein the sheet sensor and the first relay substrate are connected by a fourth wiring capable of transmitting signals.

12. A sheet storage section for storing sheets that are transported toward the photosensitive drum, A paper feed roller for feeding sheets to be stored in the sheet storage section, The system further includes a solenoid for switching the drive of the paper feed roller, The paper feed roller is located behind the motor in the front-rear direction perpendicular to the first direction. The image forming apparatus according to claim 1, wherein the solenoid and the first relay board are connected by a fifth wiring capable of transmitting signals.

13. The main housing has a rear surface positioned on the rear side in the front-rear direction perpendicular to the first direction, The system further comprises a paper discharge sensor located behind the photosensitive drum for detecting sheets discharged from the main housing, and a second relay board positioned behind the photosensitive drum and facing the rear surface. The second relay board and the main board are connected by a sixth wiring that allows signal transmission. The image forming apparatus according to claim 1, wherein the paper discharge sensor and the second relay board are connected by a seventh wiring capable of transmitting signals.

14. A high-voltage board connected to the main board by an eighth wiring capable of transmitting signals, The system further comprises a low-voltage board connected to the main board by a ninth wiring capable of transmitting signals, The image forming apparatus according to claim 1, wherein the high-voltage substrate and the low-voltage substrate are located closer to the second side surface than to the first side surface in the first direction.

15. The image forming apparatus according to claim 1, wherein the first relay substrate is positioned in the first direction closer to the first side surface than the second side surface and facing the first side surface.

Images