Image forming apparatus

Abstract

To simplify wiring of a signal line.SOLUTION: An image forming apparatus comprises: a control section 304 that is arranged on a first surface of a main body (100A) and transmits a first control signal for controlling a first exposure unit (4) and a second control signal for controlling a second exposure unit (4); and a relay section 110 that is arranged on a second surface of the main body (100A) and relays the first control signal and the second control signal transmitted from the control section 304. The relay section 110 has a receiving connector (591) that receives the first control signal and the second control signal, a first connector (581) for transmitting the first control signal received by the receiving connector (591) to the first exposure unit (4), and a second connector (582) for transmitting the second control signal received by the receiving connector (591) to the second exposure unit (4).SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus equipped with an exposure device. [Background technology]

[0002] An electrophotographic image forming apparatus forms an image by exposing a photosensitive drum. To this end, the image forming apparatus is equipped with an exposure device. The exposure device disclosed in Patent Document 1 has a plurality of light-emitting elements, such as LEDs (Light Emitting Diodes) or organic EL (electroluminescence) elements, arranged linearly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-025381 Summary of the Invention [Problem to be solved by the invention]

[0004] In the exposure device disclosed in Patent Document 1, one exposure unit (exposure device) is arranged for each of a plurality of photosensitive drums. In other words, the exposure device disclosed in Patent Document 1 is equipped with a plurality of exposure units. Since a signal line for transmitting a control signal to each of the plurality of exposure units is wired, the number of signal lines increases.

[0005] Structurally, the image forming unit, including the photosensitive drum, is located inside the main body of the image forming device. The exposure unit is also located near the photosensitive drum. In contrast, the electrical components, including the control unit for controlling the operation of the image forming unit and the exposure unit, are often located together on the back of the main body of the image forming device. This can lead to complex wiring of the signal lines that send control signals to the exposure unit.

[0006] SUMMARY OF THE INVENTION In view of the above-mentioned problems, a main object of the present invention is to provide an image forming apparatus in which the wiring of signal lines is simplified. [Means for solving the problem]

[0007] The image forming apparatus of the present invention comprises a main body having a first surface and a second surface, a first photosensitive member disposed inside the main body and carrying a first toner image, a first exposure unit disposed inside the main body and exposing the first photosensitive member, a second photosensitive member disposed inside the main body and carrying a second toner image, a second exposure unit disposed inside the main body and exposing the second photosensitive member, a control unit disposed on the first surface of the main body and transmitting a first control signal for controlling the first exposure unit and a second control signal for controlling the second exposure unit, and a relay unit disposed on the second surface of the main body and relaying the first control signal and the second control signal transmitted from the control unit, wherein the relay unit has a receiving connector for receiving the first control signal and the second control signal, a first connector for transmitting the first control signal received by the receiving connector to the first exposure unit, and a second connector for transmitting the second control signal received by the receiving connector to the second exposure unit. [Effects of the Invention]

[0008] According to the present invention, it is possible to simplify the wiring of the control signals transmitted to the exposure unit. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an image forming apparatus. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 4 is a perspective view of the exposure unit attached to the cartridge tray. [Figure 5] Cross section B-B of Figure 4. [Figure 6] FIG. [Figure 7] Cross section AA of Figure 1. [Figure 8] Cross section CC of Figure 7. [Figure 9] FIG. 2 is an explanatory diagram of an electrical component of the image forming apparatus. [Figure 10] FIG. [Figure 11] FIG. 2 is a diagram illustrating the left side configuration of the image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0011] Fig. 1 is a diagram showing the configuration of an image forming apparatus according to this embodiment. The image forming apparatus 100 according to this embodiment is a tandem-intermediate transfer type four-color full-color printer using an electrophotographic process. The image forming apparatus 100 forms an image on a sheet S based on a signal input to a control unit (not shown) from an external device (not shown), such as a personal computer. Fig. 1 shows the internal configuration of the image forming apparatus 100 as seen from the front.

[0012] Image forming apparatus 100 has image forming section 1 disposed approximately in the center of main body 100A for forming toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). Image forming section 1 has four image creating units U corresponding to the four colors. The four image creating units U have approximately the same configuration. Here, the configuration of image creating unit U that forms a cyan toner image will be described, and descriptions of the configurations of image creating units U that form toner images of the other colors will be omitted.

[0013] The imaging unit U includes a drum unit and a developing unit. The drum unit includes a rotating drum-type electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum") 2, which is an image carrier. The developing unit includes a developing sleeve 5 that develops an electrostatic latent image formed on the photosensitive drum 2 to generate a toner image. The drum unit and developing unit are replaceable and detachable from the image forming apparatus 100.

[0014] The drum unit includes a photosensitive drum 2, a charging roller 3 that charges the surface of the photosensitive drum 2, and a drum cleaner (not shown). The development unit includes a developing sleeve 5 and a screw 7 that agitates toner and supplies the agitated toner to the developing sleeve 5. Between the drum unit and the development unit, an exposure unit 4 having a plurality of light-emitting elements such as LED elements and organic EL elements is arranged as an exposure device.

[0015] A cartridge tray 30 that guides the drum unit and the developing unit when they are inserted into the image forming apparatus 100 is disposed below the imaging unit U. A cooling unit 60 including a fan 62 for cooling the exposure unit 4 is disposed below the cartridge tray 30.

[0016] An intermediate transfer belt unit 8 is provided above the image forming unit 1, and a sheet cassette 12 is provided below it. The intermediate transfer belt unit 8 includes four primary transfer rollers 6 arranged opposite the photosensitive drums 2 of each color, a belt drive roller 10, and a belt 9. The sheet cassette 12 includes two cassettes: cassette 12A arranged on the upper level, and cassette 12B arranged on the lower level.

[0017] Toner bottles 22Y, 22M, 22C, and 22K corresponding to each color are arranged above the intermediate transfer belt unit 8. The toner bottles 22Y, 22M, 22C, and 22K contain replenishment toner for each development unit of the four image forming units U. The toner bottles 22Y, 22M, 22C, and 22K are detachable and replaceable. An appropriate amount of toner is replenished to each development unit of the four image forming units U from the corresponding toner bottles 22Y, 22M, 22C, and 22K at the appropriate time by a toner replenishment mechanism (not shown).

[0018] In the image formation process, an electrostatic latent image is formed on each photosensitive drum 2 of the four imaging units U. As a preparatory operation, a high voltage is applied to the charging roller 3 while it is pressed against the photosensitive drum 2, uniformly charging the surface of the rotating photosensitive drum 2. The light-emitting elements of the exposure unit 4 irradiate the uniformly charged surface of the photosensitive drum 2 with light. The exposure unit 4 is an exposure section that controls the light emission of each light-emitting element based on a control signal representing an image sent from a control section (not shown). The potential on the surface of the photosensitive drum 2 is different between the position irradiated with light and the position not irradiated with light. As a result, an electrostatic latent image corresponding to the control signal is formed on the surface of the photosensitive drum 2.

[0019] The developing sleeve 5 has a built-in magnet, and the surface is uniformly coated with charged toner from inside the developing unit. Inside the developing unit, the toner is circulated and transported at high speed by a screw 7. The rotation speed of the screw 7 is much faster than the rotation speeds of the developing sleeve 5 and the photosensitive drum 2. This allows the toner to be coated evenly and uniformly on the developing sleeve 5. A high voltage is applied to the developing sleeve 5 via a route different from that of the charging roller 3, causing the toner to adhere to the electrostatic latent image and develop it. This forms a toner image on the photosensitive drum 2.

[0020] The toner images of each color formed on each photosensitive drum 2 are sequentially transferred (primary transfer) onto the surface of the belt 9, which is rotated counterclockwise in the drawing by the belt drive roller 10. In this embodiment, the toner images are transferred in the order of yellow, magenta, cyan, and black. As a result, the toner images of each color are formed on the belt 9 in a superimposed manner.

[0021] When viewed from the front, image forming apparatus 100 has a sheet transport path disposed on the right side of the image forming unit for transporting sheet S from bottom to top. In the sheet transport path, a pair of paper feed rollers 13, a pair of registration rollers 15, a secondary transfer roller 16, a fuser 19, and a pair of discharge rollers 20 are provided in this order from bottom to top. The secondary transfer roller 16 abuts against a belt drive roller 10 of the intermediate transfer belt unit 8 with a predetermined pressing force via the belt 9, forming a secondary transfer nip portion 17 between the secondary transfer roller 16 and the belt 9.

[0022] The pair of paper feed rollers 13 is driven at a predetermined control timing according to the image forming process, and separates and feeds the sheets S one by one from the sheet cassette 12. The fed sheets S are transported to the pair of registration rollers 15 via a sheet transport path. The pair of registration rollers 15 corrects skew of the sheet S and transports the sheet S to the secondary transfer nip portion 17 in accordance with the timing at which the toner image transferred to the belt 9 is transported to the secondary transfer nip portion 17.

[0023] The secondary transfer nip portion 17 sandwiches and transports the belt 9 and the sheet S. The secondary transfer nip portion 17 performs a secondary transfer of the four color toner images on the belt 9 onto the sheet S all at once. As a result, an unfixed toner image is formed on the sheet S. The sheet S is transported from the secondary transfer nip portion 17 to a fuser 19. The fuser 19 heats and pressurizes the sheet S on which the toner image has been formed, thereby fixing the toner image to the sheet S. The sheet S on which the toner image has been fixed by the fuser 19 is discharged as an image-formed product by a pair of discharge rollers 20 onto a discharge tray 21 provided above the toner bottles 22Y, 22M, 22C, and 22K.

[0024] (Exposure unit) Fig. 2 is a perspective view from above of the exposure unit 4. Fig. 3 is a perspective view from below of the exposure unit 4. Note that when the exposure unit 4 is attached to the image forming apparatus 100 as shown in Fig. 1, the direction in which the photosensitive drum 2 is located as viewed from the exposure unit 4 is above the exposure unit 4. Also, in Fig. 1, the direction in which the cooling unit 60 is located as viewed from the exposure unit 4 is below the exposure unit 4.

[0025] As shown in FIG. 2, the exposure unit 4 has a shape that extends in the drum axis direction of the photosensitive drum 2 when installed in the image forming apparatus 100. In other words, the longitudinal direction of the exposure unit 4 is approximately parallel to the drum axis direction of the photosensitive drum 2. The exposure unit 4 has a lens assembly 49 on its upper part. The lens assembly 49 is fixed to a holder 41 with an adhesive or the like. A slit is formed on the surface of the holder 41 that faces the photosensitive drum 2. The lens assembly 49 is inserted into the slit. Light output from each light-emitting element of the exposure unit 4 is imaged on the surface of the photosensitive drum 2 by the lens assembly 49. The holder 41 is supported by a support member 42.

[0026] As shown in FIG. 3, the exposure unit 4 includes a mounting substrate 50. A plurality of light-emitting elements are arranged in the longitudinal direction on a first surface of the mounting substrate 50 facing the lens assembly 49. More specifically, the mounting substrate 50 includes a printed circuit board on which wiring and the like are formed. The mounting substrate 50 further includes a plurality of chips mounted on the first surface of the printed circuit board. A plurality of light-emitting elements are formed on each of the plurality of chips. As described above, the plurality of light-emitting elements may be LED elements, organic EL elements, or the like. The mounting substrate 50 is fixed to the holder 41 with an adhesive or the like. Since the light-emitting elements are present on the first surface of the mounting substrate 50, the first surface of the mounting substrate 50 is a light-emitting surface.

[0027] As shown in FIG. 3, a connector 57 is mounted on a second surface of the mounting board 50 opposite the first surface. A flexible flat cable (hereinafter referred to as "FFC") 58 is connected to the connector 57 as a signal line for transmitting control signals for driving and controlling the light-emitting elements. The connector 57 is provided near one end of the exposure unit 4 in the longitudinal direction of the exposure unit 4. In this embodiment, the connector 57 is located on the front side of FIG. 1 when the exposure unit 4 is attached to the image forming apparatus 100. Also, as shown in FIG. 3, the second surface of the mounting board 50 is exposed to a space surrounded by the holder 41 and the support member 42. As can be seen from FIG. 3, an opening is provided in the bottom surface of the support member 42, which communicates with the space and the outside of the exposure unit 4. In this embodiment, three openings 43a to 43c are formed.

[0028] Next, a state in which the exposure unit 4 is attached to the image forming apparatus 100 will be described. When attached to the image forming apparatus 100, the exposure unit 4 of this embodiment is configured integrally with the cartridge tray 30. Figure 4 is a perspective view from above of the exposure unit 4 attached to the cartridge tray 30. Figure 5 is a cross-sectional view taken along line BB in Figure 4.

[0029] The cartridge tray 30 is a tray that mounts a drum unit and a developing unit and guides insertion into the main body 100A of the image forming apparatus 100. The exposure unit 4 is disposed in the space between the drum unit and the developing unit, which is approximately in the center of the cartridge tray 30. An inner door 102 is rotatably provided at the front end of the cartridge tray 30. The front end of the cartridge tray 30 is the part that is located on the front side of FIG. 1 when the cartridge tray 30 is attached to the image forming apparatus 100. The inner door 102 is rotatably provided to close the opening for attaching the imaging unit U after the imaging unit U is attached to the image forming apparatus 100.

[0030] The cartridge tray 30 is provided with a lifting duct 69 in approximately the center that can be raised and lowered in the vertical direction in Figure 5. The exposure unit 4 is attached to the lifting duct 69 in the W direction, thereby being configured as one unit with the cartridge tray 30. The lifting duct 69 is cylindrical with openings at the top and bottom ends. The lifting duct 69 is configured to communicate with the back surface (second surface) of the mounting board 50 of the exposure unit 4 when the exposure unit 4 is attached. In other words, the space where the second surface of the mounting board 50 is exposed and the space surrounded by the lifting duct 69 communicate with each other via the opening in the bottom surface of the support member 42 and the opening at the top end of the lifting duct 69.

[0031] FFC 58 is arranged to overlap with lifting duct 69 so as not to interfere with the insertion of the drum unit and development unit into image forming apparatus 100. In other words, when viewed from the front side of the apparatus, FFC 58 is located in front of lifting duct 69. FFC 58 transmits signals in the direction indicated by arrow X in FIG. 5.

[0032] (cooling unit) The exposure unit 4 dissipates heat when the light-emitting elements are driven. In particular, when the image formation process is repeated frequently (high productivity) or when images with high image density are output continuously, the light-emitting elements emit light for a long time and emit a large amount of light. This increases the amount of heat generated by the exposure unit 4. The exposure unit 4 is also located near the development unit that uses toner. Toner is easily altered by the effects of heat. Therefore, the image forming apparatus 100 of this embodiment is equipped with a cooling unit 60 for cooling the exposure unit 4.

[0033] FIG. 6 is a perspective view of a cooling unit 60 that cools the exposure unit 4. The cooling unit 60 has two fans 62, 63 at its end. One of the two fans 62, 63 functions as an intake fan that takes in fresh air (air outside the image forming apparatus 100), and the other functions as an exhaust fan that exhausts air. The fans 62, 63 are provided on either side of the main body 100A of the image forming apparatus 100. In this embodiment, the fans 62, 63 are provided on the left side of the main body 100A. The fan 62, which is located closer to the front of the image forming apparatus 100, functions as an intake fan, and the fan 63, which is located closer to the back, functions as an exhaust fan.

[0034] Providing a large space in front of the fan allows for an increased intake and exhaust volume of the fan. For this reason, in the prior art, it was considered preferable not to place any obstructions around the image forming apparatus 100. In contrast, in this embodiment, the fans 62 and 63 are arranged on one surface. Therefore, even if an obstruction is placed near one surface of the image forming apparatus 100, the intake and exhaust volume of the fans 62 and 63, and thus the cooling performance of the cooling unit 60, can be maintained. Furthermore, when the intake fan and the exhaust fan are spaced apart, as in this embodiment, the cooling performance of the cooling unit 60 can be improved. This is because, even if high-temperature air is released from the exhaust fan, the temperature of the air taken in by the intake fan is less likely to rise.

[0035] As shown in FIG. 1, the cooling unit 60 is disposed directly below the cartridge tray 30. The cooling unit 60 is configured to communicate with the mounting board 50 inside the exposure unit 4 through a lift duct 69. The cooling unit 60 includes an intake duct 64 that sends fresh air supplied by the fan 62 to the lift duct 69, and an exhaust duct 65 that sends the air used to cool the exposure unit 4 to the fan 63. Four openings 66a are provided on the upper surface of the intake duct 64. Four openings 66b are provided on the upper surface of the exhaust duct 65. In FIG. 6, the openings 66a and 66b corresponding to the cyan imaging unit U are labeled with reference numerals. The opening 66a of the intake duct 64 communicates with the opening 43a (FIG. 3) of the support member 42 of the exposure unit 4 through the lift duct 69. Opening 66b of exhaust duct 65 communicates with opening 43c (FIG. 3) of support member 42 of exposure unit 4 via lift duct 69. In this way, cooling unit 60 is arranged utilizing the space directly below image forming section 1, and is able to efficiently cool exposure unit 4 via the shortest airflow path (see FIG. 1).

[0036] 7 and 8, the airflow path for cooling the exposure unit 4 by the cooling unit 60 will be described. FIG. 7 is a cross-sectional view taken along line AA in FIG. 1. The upper side of FIG. 7 corresponds to the rear side of the main body 100A of the image forming apparatus 100. FIG. 7 shows the lifting duct 69 in a transparent state so that the positional relationship between the cooling unit 60 and the cartridge tray 30 can be clearly seen. In the following description, the suffixes Y, M, C, and K indicate the corresponding colors (yellow, magenta, cyan, and black).

[0037] 7 and 8, the airflow path of the cooling unit 60 is indicated by dashed lines. The fan 62 draws fresh air from outside the image forming apparatus 100 into the image forming apparatus 100. The air drawn into the image forming apparatus 100 passes through the interior of the lifting / lowering ducts 69 (69Y, 69M, 69C, 69K) from below the cartridge trays 30 (30Y, 30M, 30C, 30K) corresponding to each color. The air passes through the lifting / lowering ducts 69 and is sent to a space surrounded by the holder 41 and the support member 42. The second surface of the mounting board 50 is exposed in this space. Therefore, the sent air cools the mounting board 50. The air then passes through the lifting / lowering ducts 69 and the exhaust duct 65 and is exhausted to the outside of the image forming apparatus 100 via the fan 63. In this manner, the cooling unit 60 cools the exposure unit 4.

[0038] The cooling unit 60 is disposed in the space between the front plate 122 and the rear plate 123. The front plate 122 is a side plate that is disposed closer to the front of the image forming apparatus 100 than the cooling unit 60, and the rear plate 123 is a side plate that is disposed closer to the rear of the image forming apparatus 100 than the cooling unit 60. The imaging unit U is provided between the front plate 122 and the rear plate 123. Because the cooling unit 60 is disposed between the front plate 122 and the rear plate 123, the exposure unit 4 is cooled efficiently via the shortest airflow path.

[0039] The arrangement of the FFC 58 in Fig. 7 will be described. The FFC 58 is connected to the exposure units 4 for each color from the left side surface of the image forming apparatus 100, passing through an area 70 in Fig. 7. The area 70 is the space between the front panel 122 and the cooling unit 60. Because the FFC 58 is routed in this way, it does not interfere with the airflow path of the cooling unit 60. Therefore, the FFC 58 does not reduce cooling efficiency.

[0040] FIG. 8 is a cross-sectional view taken along CC in FIG. 7. To avoid cluttering the drawing, the reference numerals for the components of the exposure unit 4 shown in FIG. 5 have been omitted. Starting from the bottom of the image forming apparatus 100, the cooling unit 60, the lifting ducts 69 (69Y, 69M, 69C, 69K), and the exposure units 4 (4Y, 4M, 4C, 4K) are arranged vertically stacked. Fresh air drawn in by the fan 62 passes through the intake duct 64 of the cooling unit 60 and is blown onto the exposure units 4 (4Y, 4M, 4C, 4K). The air that enters the exposure unit 4 travels toward the rear side of the main body 100A, passes through the lifting duct 69, and enters the exhaust duct 65 of the cooling unit 60. The air inside the exhaust duct 65 is then exhausted to the left side of the image forming apparatus 100 by the fan 63. The cross-sectional configuration of the exhaust duct 65 is substantially the same as that of the intake duct 64.

[0041] (Signal transmission path to exposure unit) Fig. 9 is an explanatory diagram of the electrical components of the image forming apparatus 100. Fig. 9 shows the arrangement of a plurality of electrical components such as a control unit and the connections between the electrical components when the image forming apparatus 100 is viewed from the rear side.

[0042] The electrical components of the present embodiment include a power supply unit 300 to which a power cable is connected, and control units 301, 302, 303, and 304 that control the various units within the image forming apparatus 100. The power supply unit 300 receives power from a commercial power source via a power cable 290. The power supply unit 300 supplies power to each of the control units 301, 302, 303, and 304 based on the power supplied from the commercial power source. In the present embodiment, the control unit 304 controls the exposure unit 4. The control unit 304 is, for example, a controller that controls the entire image forming apparatus 100. The power supply unit 300 and the control units 301 to 304 are provided on the rear side of the main body 100A of the image forming apparatus 100. The control unit 304 is located at the top of the power supply unit 300 and the control units 301 to 304. The power supply unit 300 and the control units 301 to 304 are, for example, configured by an electric circuit board on which electrical components are mounted. A relay unit 110 is provided on the left side surface (the right side in FIG. 9) of a main body 100A of the image forming apparatus 100.

[0043] An FFC 59 connects the control unit 304 and the relay unit 110. The FFC 59 is a single cable that includes all signal lines for transmitting control signals for the exposure units 4 of yellow, magenta, cyan, and black. The control signals for the exposure units 4 are generated based on image data. The exposure units 4 are controlled by the control signals, thereby forming electrostatic latent images and toner images on the corresponding photosensitive drums 2. Connectors are provided on both ends of the FFC 59. One connector of the FFC 59 is connected to the control unit 304, and the other connector is connected to the relay unit 110. As shown in FIG. 9, the FFC 59 is disposed so as to extend from the connector of the control unit 304 toward the left side surface of the main body 100A of the image forming apparatus 100. After reaching the left side surface of the main body 100A, the FFC 59 is further routed along the left side surface of the main body 100A and connected to the relay unit 110 (FIG. 10).

[0044] The relay unit 110 separates the control signals for the exposure units 4 of each color (yellow, magenta, cyan, and black) transmitted by the FFC 59, and transmits them to the corresponding exposure units 4. For this purpose, four FFCs 58 corresponding to the exposure units 4 of the four colors are connected to the relay unit 110. Each of the four FFCs 58 is connected to a corresponding exposure unit 4. In this configuration, the control signals for each color are transmitted from the control unit 304 to the exposure units 4 via the relay unit 110 by the FFCs 59 and FFCs 58.

[0045] Furthermore, a cable 280 connects the control unit 302 and the relay unit 110. The cable 280 includes a plurality of bundled wires. The cable 280 supplies power from the control unit 302 to a semiconductor device mounted on the relay unit 110. The semiconductor device mounted on the relay unit 110 is, for example, an ASIC (Application Specific Integrated Circuit). An opening 270 is provided on the rear surface of the image forming apparatus 100. One connector of the cable 280 is connected to the control unit 302, and the other connector passes through the opening 270 from the rear surface of the main body 100A of the image forming apparatus 100 around to the left side surface and is connected to the relay unit 110. Note that the control unit 302 in this embodiment outputs a control signal for controlling the operation of the fans 62 and 63.

[0046] The arrangement of the FFCs 58, 59 on the left side surface of the main body 100A will be described. Fig. 10 is a perspective view of the image forming apparatus 100 from the left front. Fig. 10 shows the image forming apparatus 100 with the exterior cover removed. To make it easier to understand the signal transmission path to the exposure unit 4, Fig. 10 shows only the frame 101 of the image forming apparatus 100 and the peripheral components of the signal transmission path.

[0047] As described with reference to FIG. 9 , the FFC 59 is routed from the rear side to the left side of the image forming apparatus 100 (frame 101). As shown in FIG. 10 , the FFC 59 is arranged on the left side of the image forming apparatus 100, from the upper rear to the lower rear. The FFC 59 is then bent forward and connected to the relay unit 110. The relay unit 110 is an electrical board that divides the control signals for each color transmitted by the FFC 59 into individual color signals and transmits them to the corresponding exposure units 4 via the FFCs 58. The multiple FFCs 58 connected to the relay unit 110 are arranged in a stacked manner. The multiple FFCs 58 are arranged on the left side of the image forming apparatus 100 (frame 101), from the rear side to the front side. The FFC 59 is then bent toward the right. The multiple FFCs 58 then pass under the cartridge tray 30 (area 70 in FIG. 7 ) and are connected to the corresponding exposure units 4. 10 shows an inner door 102 arranged on the front side of the image forming apparatus 100 for inserting and removing the cartridge tray 30. The cartridge tray 30 is arranged on the back side of the corresponding inner door 102.

[0048] As described above, the cable 280 that passes through the rear surface of the main body 100A and goes around through the opening 270 is connected to the relay unit 110. The cable 280 that passes through the opening 270 goes around below the fan 63 and is connected to the relay unit 110. The cable 280 is connected to the relay unit 110 in a different arrangement and route from the FFC 59.

[0049] 11 is a structural diagram of the left side of the frame 101 of the image forming apparatus 100. A front side plate 122 and a rear side plate 123 are connected by a stay 120. The relay section 110 is fixed at multiple points to the stay 120 and a stay 121, which is a frame component, with screws. This allows the relay section 110 to be firmly fixed to the frame 101, and at the same time, the fixed points stabilize the ground potential.

[0050] An FFC 59, which is routed from the upper rear of the left side of the image forming apparatus 100, is branched by a relay unit 110 into multiple FFCs 58 corresponding to each color. To this end, the relay unit 110 is provided with a receiving connector 591 to which the FFC 59 is connected and connectors 581 to 584 to which the multiple FFCs 58 are connected. A control signal output from the control unit 304 is transmitted to the relay unit 110 by the FFC 59, separated by the relay unit 110 for each color, and transmitted to each exposure unit 4 by the FFC 58. The multiple FFCs 58 corresponding to each color are arranged overlapping each other. Each FFC 58 is bent in a direction toward the inside of the image forming apparatus 100, passing above the fan 62. Each FFC 58 is then routed below the cartridge tray 30. Because the exposure units 4 are arranged side by side in a substantially vertical direction on the left side of the image forming apparatus 100, the FFCs 58 are bent substantially vertically for routing.

[0051] The relay section 110 is disposed between the fan 62 and the fan 63. In this embodiment, the fan 62, the relay section 110, and the fan 63 are arranged in this order from the front to the rear in the front-rear direction of the image forming apparatus 100 (the left-right direction in FIG. 11 ). The cooling unit 60 is disposed so as to be compact and efficiently cool the exposure unit 4. As described above, the cooling performance of the cooling unit 60 is improved by disposing the fan 62 and the fan 63 at a distance from each other. Therefore, by disposing the relay section 110 between the fan 62 and the fan 63, the image forming apparatus 100 can be made more compact. Furthermore, in order to not obstruct the airflow path of the cooling unit 60 and to dispose the relay section 110 close to the exposure unit 4, it is appropriate to dispose the relay section 110 in the space between the fan 62 and the fan 63.

[0052] The relay unit 110 includes an ASIC 118 and a connector 114. A cable 280 runs from the control unit 302 through the opening 270, wraps around the left side surface of the main body 100A, and wraps around below the fan 63 to be connected to the connector 114. The ASIC 118 is responsible for part of the processing of the control signals to be sent to the exposure unit 4.

[0053] By implementing the ASIC 118 in the relay unit 110 instead of the control unit 304, the control signal for the exposure unit 4 is processed near the exposure unit 4. This shortens the input path of the processed control signal to the exposure unit 4. Furthermore, since the processing for controlling the exposure unit 4 is concentrated in the relay unit 110, it is possible to easily accommodate changes to the exposure unit 4. This increases the scalability.

[0054] The relay unit 110 includes fan connectors 112 and 113. Signal lines (wire bundles) that transmit drive signals for controlling the drive of the fans 62 and 63 are connected to the fan connectors 112 and 113, respectively. This means that control signals are transmitted to the fans 62 and 63 via the relay unit 110. Because the relay unit 110 is disposed between the fans 62 and 63, it is possible to aggregate the transmission paths of the control signals to the fans 62 and 63 at the relay unit 110. This makes it possible to reduce the number of signal lines, etc., for transmitting control signals to the fans 62 and 63, thereby achieving cost reduction.

[0055] The cable 280 not only transmits control signals for the fans 62 and 63, but also supplies power to the fans 62 and 63. The relay unit 110 generates drive signals for the fans 62 and 63 based on the control signals for the fans 62 and 63 obtained from the control unit 302 via the cable 280. In this way, the relay unit 110 is connected to two clearly separated systems: the FFC 59 that transmits control signals for each exposure unit 4, and the cable 280 that transmits other signals and power. This means that signals are input to the relay unit 110 separately via the FFC 59 used for transmitting high-speed control signals that are highly affected by noise, and the cable 280 used for transmitting power that is less affected by noise. This reduces the possibility of noise contamination due to mutual interference.

[0056] The connectors for the fans 62, 63 and relay unit 110 are all concentrated on the left side of the image forming apparatus 100. Therefore, the fans 62, 63 and FFCs 58, 59 can be easily replaced by removing the left cover of the image forming apparatus 100. In this way, consolidating these on one side of the image forming apparatus 100 is also advantageous from the perspective of serviceability. In this embodiment, they are concentrated on the left side, but they may be concentrated on another side.

[0057] The FFC 59 used to transmit the control signals for each color from the control unit 304 to the relay unit 110 is a shielded FFC covered with a shield that is effective for noise suppression. The FFC 58 used to transmit the control signals from the relay unit 110 to the exposure units 4 corresponding to each color is a shieldless FFC that is not at least partially covered with a shield that is effective for noise suppression. Shielded FFCs are more expensive, stiffer, and bulkier than shieldless FFCs. For this reason, shielded FFCs are less convenient than shieldless FFCs in terms of wiring management.

[0058] Because the path from the control unit 304 to the relay unit 110 is long and has few bends, it is appropriate to use a shielded FFC, which is effective at suppressing noise, for FFC 59. For FFC 58, which is wired in a location where four FFCs are stacked and has many bends, it is appropriate to use a shielded FFC, which is easy to handle. Because the path of FFC 58 is short, even if it is a shielded FFC, there is little chance that noise will affect the signal. By using different types of FFC depending on the wiring location in this way, it is possible to minimize the impact of noise on the signal while suppressing increases in costs.

[0059] The image forming apparatus 100 of this embodiment includes a relay unit 110. Therefore, transmission of control signals from the control unit 304 to the exposure unit 4 can be achieved by wiring a simple signal line. Note that, although the description has been given of the case where the exposure unit 4 is an exposure unit in which a plurality of light-emitting elements are arranged in one direction in this embodiment, the configuration of the exposure device is not limited to this. The configuration of the image forming apparatus 100 described above is effective as long as an exposure device is provided for each color corresponding to the photosensitive drum 2 of each color. For this purpose, the exposure device may employ, for example, a laser scanning system in which the photosensitive drum 2 is scanned by the rotation of a rotary polygon mirror.

Claims

1. a body having a first surface and a second surface; a first photoreceptor disposed inside the main body and carrying a first toner image; a first exposure unit disposed inside the main body and configured to expose the first photosensitive member; a second photoreceptor disposed inside the main body and carrying a second toner image; a second exposure unit disposed inside the main body and configured to expose the second photosensitive member; a control unit disposed on the first surface of the main body and configured to transmit a first control signal for controlling the first exposure unit and a second control signal for controlling the second exposure unit; a relay unit that is disposed on the second surface of the main body and relays the first control signal and the second control signal transmitted from the control unit, The relay unit is a receiving connector for receiving the first control signal and the second control signal; a first connector for transmitting the first control signal received by the receiving connector to the first exposure unit; a second connector for transmitting the second control signal received by the receiving connector to the second exposure unit, Image forming device.

2. a first flexible flat cable that connects the control unit and the receiving connector of the relay unit and transmits the first control signal and the second control signal; a second flexible flat cable that connects the first connector of the relay unit and the first exposure unit and transmits the first control signal; a third flexible flat cable that connects the second connector of the relay unit and the second exposure unit and transmits the second control signal, 2. The image forming apparatus according to claim 1.

3. the first flexible flat cable is covered with a shield; The second flexible flat cable and the third flexible flat cable are at least partially not covered with a shield.

3. The image forming apparatus according to claim 2.

4. The first flexible flat cable is a signal line that is more effective in suppressing noise than the second flexible flat cable and is also a signal line that is more effective in suppressing noise than the third flexible flat cable.

3. The image forming apparatus according to claim 2.

5. an intake fan that draws in air for cooling the first exposure unit and the second exposure unit; An exhaust fan that exhausts the air, 2. The image forming apparatus according to claim 1.

6. The intake fan and the exhaust fan are disposed on the second surface of the main body.

6. The image forming apparatus according to claim 5.

7. The relay unit is provided between the intake fan and the exhaust fan.

7. The image forming apparatus according to claim 6.

8. each of the first exposure unit and the second exposure unit includes a substrate having a light-emitting surface on which a plurality of light-emitting elements are arranged, and a lens disposed opposite the light-emitting surface; The air is blown onto a surface of the substrate opposite to the light-emitting surface, thereby cooling the substrate.

6. The image forming apparatus according to claim 5.

9. The relay unit transmits a drive signal for controlling the drive of the intake fan and the exhaust fan.

6. The image forming apparatus according to claim 5.

10. the relay unit has a first fan connector to which a signal line for transmitting a drive signal to the intake fan is connected, and a second fan connector to which a signal line for transmitting a drive signal to the exhaust fan is connected, 10. The image forming apparatus according to claim 9.

11. the intake fan and the exhaust fan are disposed on the second surface of the main body, The relay unit is provided between the first fan and the second fan. The image forming apparatus according to claim 10.

Images