Image forming apparatus

Abstract

To facilitate maintenance work in a casing.SOLUTION: The printer 100 includes an image forming unit 1, a conveying unit 2, a substrate 71, and a housing side 100A that accommodates the image forming unit 1, the conveying unit 2, and the substrate 71. The housing side 100A includes a frame 80 and five covers. The substrate 71 is disposed between the conveyance unit 2 and the image forming unit 1, and the cover on the D2 in the left-right direction. The length L1 of the side D1 in the front-rear direction of the substrate 71 is equal to or less than half the length L of the side D1 in the front-rear direction of the housing side 100A.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that forms an image on a recording medium. [Background technology]

[0002] Patent Document 1 describes an image forming apparatus including a high-voltage unit that supplies power to a drive unit. The high-voltage unit of this image forming apparatus has a high-voltage circuit board that is elongated in one direction (second direction). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-9421 Summary of the Invention [Problem to be solved by the invention]

[0004] In the image forming apparatus described in Patent Document 1, the length of the high-voltage circuit board in one direction is more than half the length of the apparatus main body (housing) in one direction. Therefore, when the cover covering the high-voltage unit of the apparatus main body is removed, more than half of the inside of the apparatus main body in one direction is covered by the high-voltage circuit board (high-voltage unit). Therefore, it is difficult to perform maintenance work inside the apparatus main body unless the high-voltage circuit board and other components are removed first.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus in which maintenance work inside the housing is easy. [Means for solving the problem]

[0006] The image forming apparatus of the present invention comprises a transport unit that transports a recording medium, an image forming unit that forms an image on the recording medium transported by the transport unit, a substrate having a first surface and a second surface opposite to the first surface and having electronic components mounted on at least one of the first surface and the second surface, a frame that supports the transport unit, the image forming unit, and the substrate, and a housing that is detachable from the frame and includes a cover that covers the transport unit, the image forming unit, and the substrate in a first direction that is perpendicular to the vertical direction and perpendicular to the first surface, wherein the substrate is positioned between the transport unit and the image forming unit and the cover in the first direction, and the length of the substrate is less than half the length of the housing in a second direction that is perpendicular to both the vertical direction and the first direction. [Effects of the Invention]

[0007] According to the image forming apparatus of the present invention, when the cover is removed, at least half of the interior of the housing is exposed to the outside without being covered by the circuit board in the second direction, which makes it easier to perform maintenance work on the conveying unit and image forming unit inside the housing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a printer according to an embodiment of the present invention as viewed from the left front. [Figure 2] FIG. 2 is a schematic plan view showing the internal configuration of the printer shown in FIG. [Figure 3] FIG. 2 is a left side view of the printer shown in FIG. [Figure 4] 2 is a perspective view of the main part of the printer shown in FIG. 1 with covers 91 and 93 removed. FIG. [Figure 5] FIG. 4 is a left side view of the printer shown in FIG. 3 with two covers 91 and 93 removed. [Figure 6] FIG. [Figure 7] FIG. 2 is a block diagram showing the electrical configuration of the printer. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Embodiment> First, with reference to FIGS. 1 and 2, the overall configuration of a printer 100 according to one embodiment of the present invention will be described. The printer 100 according to this embodiment is a so-called multifunction device that is capable of printing on paper 9 (recording medium) as well as reading images. In the following description, the front-rear direction D1 and the left-right direction D2 are horizontal directions that are perpendicular to the up-down direction D3. The front-rear direction D1 is perpendicular to the left-right direction D2. The left-right direction D2 is the direction when the printer 100 is viewed from the front. The left-right direction D2 corresponds to the "first direction" of the present invention, and the front-rear direction D1 corresponds to the "second direction" of the present invention. In this embodiment, the up-down direction D3 is aligned with the vertical direction, but it may also be an up-down direction that intersects with the vertical direction. In this case, it is sufficient that the left-right direction and the front-rear direction are perpendicular to the up-down direction.

[0010] <Overall printer configuration> 1 and 2, the printer 100 includes a housing 100A, a scanner unit 100B, an image forming unit 1, a conveying unit 2, a paper feed tray 5, a paper discharge tray 6, an operation unit 7, a display unit 8, a power supply unit 65 (see FIG. 3), a control unit 70 (see FIG. 7), etc. The printer 100 corresponds to the "image forming apparatus" of the present invention.

[0011] Scanner unit 100B is a known scanner disposed to cover the entire upper portion of housing 100A. Scanner unit 100B includes an opening / closing cover 100B1 and an image reading unit 100B2 (see FIG. 7). Opening / closing cover 100B1 is configured so that the front portion thereof can rotate up and down about a rotation axis (a rotation axis parallel to the left-right direction D2) at the rear end. Image reading unit 100B2 is disposed between image forming unit 1 and opening / closing cover 100B1 in the up-down direction D3. When opening / closing cover 100B1 is closed, the entire upper surface of image reading unit 100B2 is covered by opening / closing cover 100B1. Image reading unit 100B2 outputs the scanned image to control unit 70.

[0012] The housing 100A has a roughly rectangular parallelepiped shape and contains the image forming unit 1, the conveying unit 2, the platen 19, the receiving unit 3, the waste liquid tank 50, the encoder 60, the power supply unit 65, a circuit board 71 that constitutes part of the function of the control unit 70, and a wireless circuit board 78.

[0013] 1, the housing 100A has an opening 100C formed in approximately the center of the front wall 100A1. A paper feed tray 5 and a paper discharge tray 6 are provided in two tiers, one above the other, in the opening 100C. In this embodiment, the paper discharge tray 6 is provided above the paper feed tray 5. The paper feed tray 5 and the paper discharge tray 6 are configured to be insertable and removable from the opening 100C in the front-rear direction D1, i.e., detachable from the housing 100A.

[0014] 1 to 3, the housing 100A includes five covers 91 to 95 and a frame 80 (see FIG. 6). The frame 80 supports the image forming unit 1, the transport unit 2, the waste liquid tank 50, the substrate 71, etc.

[0015] Of the five covers 91-95, two covers 91 and 92 form the front wall 100A1, cover 93 forms the left end portions of the left side wall 100A2 and the rear wall 100A4, cover 94 forms the right end portions of the right side wall 100A3 and the rear wall 100A4, and cover 95 forms the center portion of the rear wall 100A4 in the left-right direction D2. These five covers 91-95 are each detachably supported on the frame 80 by screws or hooks. The five covers 91-95 can be easily removed from the frame 80 by removing these screws and hooks from the frame 80. The five covers 91-95 can be easily attached to the frame 80 by reversing the removal procedure.

[0016] 1 and 4, cover 91, which forms the left side of front wall 100A1, is attached to frame 80 so as to cover the front end of substrate 71 in the front-rear direction D1. Cover 91 and cover 93 are configured to be separable from each other, and cover 93 is attached to frame 80 so as to cover image forming unit 1, conveying unit 2, receiving unit 3, waste liquid tank 50, encoder 60, power supply unit 65, and most of substrate 71 in the left-right direction D2, as shown in FIGS. 3 and 5. Cover 93 also has a recess 93A recessed toward waste liquid tank 50 in a portion that faces waste liquid tank 50 in the left-right direction D2 from the center of waste liquid tank 50 in the front-rear direction D1 to its front end.

[0017] 2 and 5, the image forming unit 1 includes a head 10 and a head moving mechanism 11. The image forming unit 1 is disposed behind a center line C passing through the center of the housing 100A in the front-to-rear direction D1. The front corresponds to the "one side" in the present invention, and the rear corresponds to the "other side" in the present invention.

[0018] As shown in FIG. 2, the head moving mechanism 11 includes a carriage 12, a pair of guides 13 and 14, a belt 15, and a carriage motor 12M (see FIG. 7). The carriage 12 holds the head 10. The pair of guides 13 and 14 support the carriage 12. The belt 15 is connected to the carriage 12. The guides 13 and 14 and the belt 15 extend in a scanning direction parallel to the left-right direction D2. When the carriage motor 12M is driven under the control of the control unit 70, the belt 15 runs, and the carriage 12 moves in the scanning direction along the guides 13 and 14.

[0019] The head 10 is supplied with ink from an ink tank (not shown). As shown in FIG. 2, the head 10 also has a plurality of nozzles N formed on its underside. The plurality of nozzles N are arranged so that four nozzle rows are aligned in the scanning direction. The nozzle rows are configured with a plurality of nozzles N aligned in the front-to-rear direction D1. From the plurality of nozzles N, black, yellow, cyan, and magenta inks are ejected, starting from the nozzle row on the right side in the scanning direction.

[0020] The platen 19 is a plate along a plane perpendicular to the up-down direction D3, and is disposed below the head 10. The upper surface of the platen 19 supports from below the paper 9 that is transported by the transport unit 2. An image is formed on the paper 9 by ejecting ink from the head 10 onto the paper 9 that is supported by the platen 19.

[0021] The transport unit 2 has two roller pairs 2A and 2B, a transport motor 2M (see FIGS. 5 and 7), and a transmission mechanism (not shown). The two roller pairs 2A and 2B are arranged in the front-rear direction D1 with the platen 19 sandwiched between them. As shown in FIG. 5, the transport motor 2M is arranged behind the center line C of the casing 100A. The transmission mechanism transmits power from the transport motor 2M to each of the roller pairs 2A and 2B.

[0022] When the conveying motor 2M is driven under the control of the control unit 70, the pair of rollers 2A and 2B rotate with the paper 9 sandwiched between them, and the paper 9 is conveyed from rear to front in a conveying direction along the front-rear direction D1. The paper 9 stored in the paper feed tray 5 is conveyed to the conveying unit 2 by a paper feed unit (not shown). The paper 9 conveyed by the conveying unit 2 is then discharged to the paper output tray 6.

[0023] 2 and 4, the encoder 60 is a known encoder including an encoder disk 61 and an optical sensor 62, and is used to detect the amount of transport of the paper 9 by the roller pair 2A. Also, as shown in FIG. 5, the encoder 60 is disposed behind the center line C of the housing 100A.

[0024] As shown in FIGS. 2 and 5, a disk fixing portion 2A1 is disposed on the left end of one of the rollers of the roller pair 2A, coaxially rotating with the roller. The encoder disk 61 is detachably attached to the disk fixing portion 2A1. The encoder disk 61 has a circular shape that is slightly larger than the disk fixing portion 2A1 and is attached to the disk fixing portion 2A1 with double-sided tape. The outer peripheral edge of the encoder disk 61 has a plurality of slits (not shown) formed along the circumferential direction. The encoder disk 61 is disposed between the waste liquid tank 50 and the cover 93 in the left-right direction D2, and is disposed so that a portion of the encoder disk 61 overlaps with a rear portion 50B (described later) of the waste liquid tank 50 in the left-right direction D2.

[0025] As shown in Figures 2 and 4, the optical sensor 62 is arranged to sandwich the outer circumferential edge of the encoder disk 61 in the left-right direction D2. More specifically, the optical sensor 62 has a light-emitting section and a light-receiving section (neither of which are shown). These light-emitting section and light-receiving section are arranged to sandwich the outer circumferential edge of the encoder disk 61 in the left-right direction D2. The optical sensor 62 also detects the presence or absence of a slit in the encoder disk 61 and outputs a detection signal to the control unit 70. The control unit 70 derives the transport amount of the paper 9 based on the detection signal from the optical sensor 62 and detects the transport amount of the paper 9.

[0026] The receiving unit 3 is a member that receives ink as waste liquid when flushing is performed, in which ink is ejected from the nozzles N while facing the head 10 in the up-down direction D3. As shown in FIG. 2, the receiving unit 3 is disposed between the guides 13 and 14 in the front-to-back direction D1. The receiving unit 3 is disposed to the left (closer to the cover 93) of the transport region R through which the paper 9 is transported by the transport unit 2. The receiving unit 3 is disposed above the waste liquid tank 50 and at a position overlapping the waste liquid tank 50 in the up-down direction D3. The receiving unit 3 guides the ink (waste liquid) received by flushing to flow into the waste liquid tank 50. By providing such a receiving unit 3, the ink ejected from the head 10 by flushing can be discharged into the waste liquid tank 50.

[0027] As shown in FIG. 2, the waste liquid tank 50 extends elongatedly in the front-rear direction D1, and the length in the front-rear direction D1 is longer than the length in the left-right direction D2. The waste liquid tank 50 has a front portion 50A including its front end, and a rear portion 50B located rearward of the front portion 50A and including its rear end. The rear portion 50B has a longer length in the left-right direction D2 than the front portion 50A. As shown in FIG. 5, the front portion 50A is positioned higher than the rear portion 50B. The waste liquid tank 50 is detachably supported by the frame 80.

[0028] 2, the waste liquid tank 50 is disposed in a position where a rear portion 50B overlaps with a connector 72 (described later) of the substrate 71 in the front-rear direction D1. The waste liquid tank 50 is disposed in a position where a front portion 50A does not overlap with the connector 72 in the front-rear direction D1. A recessed portion 93A of the cover 93 is disposed to the left of the front portion 50A and between the connector 72 and the rear portion 50B. As shown in FIG. 3, a through-hole 93B facing the connector 72 is formed in the front side surface of the recessed portion 93A. A wiring arrangement space 100D is provided in the portion surrounded by the recessed portion 93A of the cover 93, in which wiring connected to an external connector mated with the connector 72 is arranged. The wiring arrangement space 100D is disposed to the left of the waste liquid tank 50 and at a position displaced rearward from the connector 72.

[0029] The waste liquid tank 50 has a box shape that opens upward and houses an ink absorber 55 inside. In this embodiment, urethane foam capable of absorbing liquid is used as the ink absorber 55, but any absorber capable of absorbing liquid may be used. The ink absorber 55 does not have to be housed inside the waste liquid tank 50.

[0030] The frame 80 supports the image forming unit 1, the transport unit 2, the waste liquid tank 50, the encoder 60, the substrate 71, etc. The image forming unit 1 and the transport unit 2 are supported by the frame 80 via support members (not shown) including screws, etc. As shown in FIG. 6, the frame 80 also includes a tank support portion 81, an encoder support portion 82, and a substrate support portion 86. The tank support portion 81 supports the waste liquid tank 50 from below. The encoder support portion 82 supports the optical sensor 62 of the encoder 60 via a support plate 82A (see FIG. 5).

[0031] The board support portion 86 is disposed forward of the tank support portion 81 in the front-rear direction D1 and is formed of a generally plate-shaped member extending in the front-rear direction D1 and the up-down direction D3. The board support portion 86 also has three screw holes 86A to 86C for screwing the board 71. Of the three screw holes 86A to 86C, two screw holes 86A and 86B are disposed in the front, and the screw hole 86C is disposed in the rear. The three screw holes 86A to 86C are disposed in different positions from one another in the up-down direction D3. The board support portion 86 also has a notch 86D in its front portion, which is a cutout. The notch 86D extends in the up-down direction D3 from the center of the board support portion 86 in the up-down direction D3 to the vicinity of the screw hole 86A.

[0032] 2, the substrate 71 is disposed on the left side of the substrate support portion 86 and is disposed forward of the waste liquid tank 50 in the front-to-rear direction D1. In other words, the substrate 71 is disposed forward of the center line C of the housing 100A, and is disposed to the left of the waste liquid tank 50 so as not to overlap with the waste liquid tank 50 in the left-to-right direction D2. The substrate 71 is disposed between the image forming unit 1 and the conveying unit 2 and the cover 93 in the left-to-right direction D2.

[0033] As shown in FIG. 5 , the board 71 is formed of a plate-like member extending in the front-rear direction D1 and the up-down direction D3. The length L1 of the board 71 in the front-rear direction D1 is less than half the length L of the housing 100A in the front-rear direction D1. The length L2 of the board 71 in the up-down direction D3 is less than half the length L of the housing 100A. The length L2 of the board 71 is less than the length D3 of the housing 100A. In this embodiment, the length L of the housing 100A is 320 mm, the length L1 of the board 71 is 103 mm, and the length L2 of the board 71 is 110 mm, but these are not particularly limited. The length L1 of the board 71 is preferably 128 mm or less. If the length L1 of the board 71 is 128 mm, it will be less than the width of a B6-sized book. This makes it easier for an operator to hold the board 71 with one hand when attaching or detaching the board 71.

[0034] As shown in Fig. 2, electronic components such as connectors 72, 73, 75, and 77 are mounted on both left and right surfaces 71A and 71B of the substrate 71. The connectors 72, 73, and 75 are mounted on the left side surface 71A of the substrate 71, and the connector 77 and the wireless substrate 78 are mounted via the connector 77 on the right side surface 71B opposite the left side surface 71A. The left side surface 71A of the substrate 71 faces the cover 93 in the left-right direction D2. As shown in Fig. 5, the substrate 71 has a cutout portion 71C that is partially cut out to avoid overlap with the power supply unit 65 in the left-right direction D2. The left side surface 71A corresponds to the "first surface" of the present invention, and the right side surface 71B corresponds to the "second surface" of the present invention.

[0035] The connector 72 in this embodiment is a board-mounted USB female connector. The connector 72 can be mated with an external connector, which in this embodiment is a USB male connector. The connector 72 is mounted on the board 71 so that the insertion direction (forward direction) and removal direction (rear direction) of the external connector relative to the connector 72 are parallel to the front-to-rear direction D1.

[0036] Connector 73 in this embodiment is a female connector for a coaxial harness. As shown in Fig. 5, a coaxial harness 74 having a male connector 74E that can be mated with connector 73 is connected to connector 73. Male connector 74E is provided at one end (front end) of coaxial harness 74. Connector 73 corresponds to the "first connector for board" of the present invention, coaxial harness 74 corresponds to the "first wiring member" of the present invention, and male connector 74E corresponds to the "first connector for wiring" of the present invention.

[0037] As shown in FIG. 2, one end of the coaxial harness 74 is connected to the connector 73, and the other end (rear end) is connected to the optical sensor 62. As shown in FIGS. 2 and 4, the coaxial harness 74 has a first portion 74A that is located forward of the rear end of the front portion 50A of the waste liquid tank 50 in the front-rear direction D1, and is disposed below the waste liquid tank 50 and to the left of the front portion 50A. In addition, the coaxial harness 74 has a central portion 74B, one end (left end) of which is connected to the rear end of the first portion 74A, that is also disposed below the waste liquid tank 50. The central portion 74B is disposed so as to cross the waste liquid tank 50 from left to right. The coaxial harness 74 has a second portion 74C that is connected to the other end (right end) of the central portion 74B and is disposed rearward and connected to the optical sensor 62.

[0038] The connector 75 in this embodiment is also a female connector for a coaxial harness. The connector 75 is disposed at the front end of the substrate 71. As shown in FIG. 5, a coaxial harness 76 having a male connector 76E that can be mated with the connector 75 is connected to the connector 75. The male connector 76E is provided at one end (front end) of the coaxial harness 76. The connector 75 corresponds to the "second connector for the substrate" of the present invention, the coaxial harness 76 corresponds to the "second wiring member" of the present invention, and the male connector 76E corresponds to the "second connector for wiring" of the present invention.

[0039] One end of the coaxial harness 76 is connected to the connector 75, and the other end (rear end) is connected to a sensor (for example, an optical sensor of an encoder that detects the amount of movement of the carriage 12 in the scanning direction; not shown). As shown in FIGS. 2 and 4 , the coaxial harness 76 has a first portion 76A that is forward of the rear end of the front portion 50A of the waste liquid tank 50 in the front-rear direction D1, and is disposed below the waste liquid tank 50 and to the left of the front portion 50A. The coaxial harness 76 also has a central portion (not shown) whose one end (left end) is connected to the rear end of the first portion 76A, and is disposed below the waste liquid tank 50. This central portion is disposed so as to cross the waste liquid tank 50 from left to right. The coaxial harness 76 has a second portion (not shown) that is connected to the other end (right end) of the central portion and is connected to an optical sensor (not shown).

[0040] The connector 77 in this embodiment is a board-to-board connector. As shown in FIG. 2, the connector 77 is disposed at the front end of the board 71, facing the recessed portion 86D of the board support portion 86 on the right side surface 71B. A wireless board 78 is connected to the connector 77. The wireless board 78 is made of a plate-like member extending in the left-right direction D2 and the up-down direction D3, and is disposed at a position overlapping the board 71 in the left-right direction D2. Electronic components for implementing wireless functions are mounted on the wireless board 78. The wireless board 78 corresponds to the "another board" of the present invention.

[0041] The power supply unit 65 supplies power to the electronic components mounted on the substrate 71, the electronic components mounted on the wireless substrate 78, the optical sensor 62, the carriage motor 12M, the transport motor 2M, the head 10, etc. As shown in Fig. 5, the power supply unit 65 extends in the front-to-rear direction D1 and is disposed below the waste liquid tank 50. The front end of the power supply unit 65 is disposed forward of a center line C passing through the center of the housing 100A in the front-to-rear direction D1, and the rear end is disposed rearward of the center line C. In other words, a portion of the power supply unit 65 is disposed forward of the center of the housing 100A in the front-to-rear direction D1.

[0042] As shown in FIG. 7, the control unit 70 includes a CPU 70A, a ROM 70B, and a RAM 70C, and controls the operation of the head 10, carriage motor 12M, transport motor 2M, optical sensor 62, image reader 100B2, display unit 8, etc. The CPU 70A executes various controls in accordance with programs and data stored in the ROM 70B and RAM 70C based on data input from an external device or operation unit 7. The external device is, for example, a personal computer (PC). The control unit 70 also derives and detects the transport distance of the paper 9 based on a detection signal from the optical sensor 62.

[0043] The ROM 70B stores programs and data for the CPU 70A to perform various controls. The RAM 70C temporarily stores data used when the CPU 70A executes programs.

[0044] Next, the maintenance work for the printer 100 will be described below with reference to Figures 1, 4, and 5. The maintenance work in this embodiment includes replacing the circuit board 71, the encoder 60, the transport motor 2M, and the waste liquid tank 50, removing jammed paper 9, and the like.

[0045] When replacing the circuit board 71 in the printer 100, first remove the cover 91 shown in FIG. 1 from the frame 80, and then remove the cover 93 from the frame 80. Because the cover 91 covers the front end portion of the cover 91 from the outside, the cover 91 must be removed first. Opening the open-close cover 100B1 exposes the screws (not shown) that secure the cover 91 to the frame 80. After removing these screws, the cover 91 can be removed from the frame 80 by disengaging the hooks (not shown) of the cover 91 from the frame 80. Removing the cover 91 exposes the front end of the circuit board 71 to the outside, as shown in FIGS. 4 and 5. This makes it easier to insert and remove the coaxial harness 76 into and from the connector 75.

[0046] Next, two screws (not shown) that secure the portion of the left end portion of the rear wall 100A4 of the cover 93 to the frame 80 are removed. Thereafter, by disengaging the hooks (not shown) of the cover 93 from the frame 80, the cover 93 can be removed from the frame 80 as shown in FIGS. 4 and 5.

[0047] The wiring members (including coaxial harnesses 74, 76) connected to the connectors 73, 75, etc. of the board 71 are disconnected from the connectors 73, 75, so that the board 71 and the wiring members are no longer connected. After this, the three screws 89 that secure the board 71 are removed. At this time, because the length L1 of the board 71 is relatively short, the worker can remove the three screws 89 while holding the board 71 with one hand.

[0048] Next, when attaching the repaired board 71 or a new board 71 to the frame 80, the board 71 can be attached to the frame 80 by reversing the board removal procedure described above. When fixing the board 71 to the frame 80, the worker can fix the board 71 to the frame 80 with three screws 89 while holding the board 71 in one hand, without temporarily holding the board 71 with another member. In this way, the board 71 can be replaced.

[0049] 5, by removing the cover 93, the central portion and rear portion of the housing 100A in the front-rear direction D1 are exposed to the outside without being covered by the substrate 71. As a result, the encoder 60 is exposed to the outside, and if a malfunction occurs in the encoder 60, it becomes possible to easily replace the encoder 60.

[0050] Furthermore, when replacing the carry motor 2M and the waste liquid tank 50, the encoder disk 61, which is attached to the disk fixing portion 2A1 with double-sided tape, is peeled off and removed from the disk fixing portion 2A1. This ensures that there are no obstructing components of the printer 100 to the left of the carry motor 2M and the waste liquid tank 50. The carry motor 2M can be removed from the frame 80 and replaced by removing the screws (not shown) that secure it to the frame 80 from the left. The waste liquid tank 50 can be removed from the frame 80 by rotating the rear portion 50B to the left and then moving the waste liquid tank 50 rearward along its longitudinal direction. When attaching the waste liquid tank 50 to the frame 80, the waste liquid tank 50 can be attached to the frame 80 in the reverse order of the waste liquid tank removal procedure described above. In this manner, the carry motor 2M and the waste liquid tank 50 can be replaced.

[0051] Furthermore, by removing the encoder disk 61, the area between the head 10 and the platen 19 becomes accessible from the left. This makes it possible to remove paper 9 that has jammed in the area between the head 10 and the platen 19 or in the vicinity thereof. Furthermore, since the conveying unit 2 and the image forming unit 1 are also accessible from the left, if a malfunction occurs in a component that constitutes these units, the malfunctioning component can be replaced. In other words, maintenance work on the conveying unit 2 and the image forming unit 1 can be easily performed. After these replacements and other work are completed, the encoder disk 61 is attached to the disk fixing portion 2A1, and the covers 93 and 91 are attached to the frame 80, completing the maintenance work.

[0052] As described above, in the printer 100 of this embodiment, the length L1 of the circuit board 71 is equal to or less than half the length L of the housing 100A. As a result, when the cover 93 is removed, at least about half of the interior of the housing 100A in the left-right direction D2 is exposed to the outside without being covered by the circuit board 71. This makes it easier to perform maintenance work on the conveying unit 2 and image forming unit 1 inside the housing 100A.

[0053] The length L2 of the board 71 is equal to or less than half the length L of the housing 100A. As a result, the length L2 of the board 71 in the up-down direction D3 is also short, and the board 71 itself becomes relatively small. Therefore, when removing the board 71 from the frame 80, an operator can remove the screws 89 and the like that secure the board 71 while holding the board 71 with one hand. Furthermore, if the board 71 is relatively small, the board 71 can be attached to the frame 80 without being temporarily held in place by another member.

[0054] The circuit board 71 is disposed forward of the center line C of the housing 100A. As a result, when the cover 93 is removed, more than half of the interior of the housing 100A in the left-right direction D2 is continuously exposed to the outside without being covered by the circuit board 71. This makes it easier to perform maintenance work on the conveying unit 2 and the image forming unit 1.

[0055] The length L1 of the board 71 is 128 mm or less. In other words, the length L1 of the board 71 is equal to or less than the width of a B6-sized book, making the board 71 easy to hold in one hand. This makes it easy for an operator to hold the board 71 in one hand when attaching or detaching the board 71.

[0056] The circuit board 71 is disposed in front of the center line C of the housing 100A, and the carry motor 2M is disposed behind the center line C. As a result, the carry motor 2M and the circuit board 71 do not overlap in the left-right direction D2, making it possible to replace the carry motor 2M and perform maintenance work around it without removing the circuit board 71.

[0057] The encoder 60 is disposed behind the center line C of the housing 100A. This makes it easier to replace the encoder 60 and perform maintenance work around it.

[0058] The image forming unit 1 is disposed behind the center line C of the housing 100A, which makes it easier to perform maintenance work on the image forming unit 1 and its surroundings.

[0059] The cover 93 faces the left side surface 71A of the board 71 in the left-right direction D2. As a result, the left side surface 71A of the board 71 is exposed to the outside by removing the cover 93. This makes it easier to insert and remove the coaxial harness 74 into and from the connector 73.

[0060] The wireless board 78 is disposed at a position overlapping with the board 71 in the left-right direction D2. As a result, by providing a wireless board 78 separate from the board 71, the board 71 does not need to have the function of the wireless board 78, and the planar size of the board 71 can be reduced. Furthermore, because the wireless board 78 is disposed overlapping with the board 71 in the left-right direction D2, the area covered by the board 71 and the wireless board 78 in the left-right direction D2 is smaller than in a configuration in which the wireless board 78 is disposed without overlapping with the board 71 in the left-right direction D2. Therefore, even if a wireless board 78 separate from the board 71 is provided, the area covered by the board 71 and the wireless board 78 in the left-right direction D2 is unlikely to become large, and therefore, ease of maintenance work from the left after removing the cover 93 from the frame 80 can be maintained.

[0061] The board 71 has a cutout 71C to avoid overlapping with the power supply unit 65 in the left-right direction D2. This makes it possible to prevent interference with the board 71 when the power supply unit 65 is moved in the left-right direction D2 after the cover 93 is removed from the frame 80.

[0062] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims.

[0063] The length L2 of the substrate 71 in the above-described embodiment may be longer than half the length L of the housing 100A as long as it is shorter than the length D3 of the housing 100A in the up-down direction. Furthermore, the length D3 of the housing 100A in the up-down direction may be equal to or greater than the length L of the housing 100A.

[0064] The circuit board 71 may be disposed rearward of the center line C of the housing 100A. The length of the circuit board 71 in the front-to-rear direction D1 may exceed 128 mm. The conveying motor 2M, the encoder 60, and the image forming unit 1 may be disposed forward of the center line C of the housing 100A.

[0065] The circuit board 71 may be disposed to the right of the center of the housing 100A in the left-right direction D2. In this case, when the cover 94 is removed, at least about half of the interior of the housing 100A in the left-right direction D2 is exposed to the outside without being covered by the circuit board 71, as described above. This makes it easier to perform maintenance work on the conveying unit 2 and the image forming unit 1 inside the housing 100A.

[0066] The three connectors 73, 75, and 77 do not have to be mounted on the board 71. In this case, the two coaxial harnesses 74 and 76 and the wireless board 78 do not have to be provided inside the housing 100A. Also, electronic components such as connectors may be mounted only on the surface of the board 71 that faces the cover. Also, the board 71 does not have to have the cutout portion 71C.

[0067] The type of liquid ejection head of the present invention is not limited to a serial type, but may also be a line type.

[0068] The object onto which the liquid is ejected is not limited to paper, but may be, for example, a cloth, a substrate, or plastic.

[0069] The liquid ejected from the head 10 may be black ink alone, or may be a liquid other than ink. For example, the liquid may be a treatment liquid that aggregates or precipitates components in the ink.

[0070] In the present invention, the printer 100 does not necessarily have to have the scanner unit 100B. The image forming apparatus can also be applied to a facsimile or a copier. The present invention can also be applied to an electrophotographic printer equipped with a laser-type image forming unit in which an electrostatic latent image is formed by exposing a photosensitive member to a laser, or an LED-type image forming unit in which an electrostatic latent image is formed by exposing a photosensitive member to an LED. [Explanation of symbols]

[0071] 1 Image forming unit 2. Conveyor section 2M transport motor 60 Encoder 65 Power Supply Unit 71 PCB 71A left side 71B Right side 71C Missing part 73,75,77 Connectors 74,76 Coaxial harness 74E, 76E male connector 78 Wireless board 80 frames 91~95 Cover 100 printers 100A housing D1 Anteroposterior direction D2 Left / right direction D3 Up and down direction

Claims

1. a conveying unit that conveys the recording medium; an image forming unit that forms an image on the recording medium conveyed by the conveying unit; a substrate having a first surface and a second surface opposite to the first surface, and having electronic components mounted on at least one of the first surface and the second surface; a frame that supports the transport unit, the image forming unit, and the substrate; and a housing that is detachable from the frame and includes a cover that covers the transport unit, the image forming unit, and the substrate in a first direction that is perpendicular to the up-down direction and perpendicular to the first surface, the substrate is disposed between the conveying unit and the image forming unit and the cover in the first direction; an image forming apparatus, wherein the length of the substrate is equal to or less than half the length of the housing in a second direction perpendicular to both the vertical direction and the first direction;

2. 2. The image forming apparatus according to claim 1, wherein the length of the circuit board in the vertical direction is equal to or less than half the length of the housing in the second direction.

3. 2. The image forming apparatus according to claim 1, wherein the circuit board is disposed on one side in the second direction from the center of the housing in the second direction.

4. 2. The image forming apparatus according to claim 1, wherein the length of the substrate in the second direction is 128 mm or less.

5. the conveying unit has a conveying motor, 4. The image forming apparatus according to claim 3, wherein the transport motor is disposed on the other side in the second direction from the center of the housing in the second direction.

6. The recording medium conveying device further includes an encoder for detecting the amount of conveyance of the recording medium by the conveyance unit, 4. The image forming apparatus according to claim 3, wherein the encoder is disposed on the other side in the second direction from the center of the housing in the second direction.

7. 4. The image forming apparatus according to claim 3, wherein the image forming unit is disposed on the other side in the second direction from the center of the housing in the second direction.

8. The device further includes a first wiring member having a first wiring connector, the electronic component includes a first board connector that is mateable with the first wiring connector and is mounted on the first surface; 4. The image forming apparatus according to claim 3, wherein the cover faces the first surface of the substrate in the first direction.

9. a second wiring member having a second wiring connector; the electronic component includes a second board connector that is mateable with the second wiring connector and is mounted on either the first surface or the second surface; the second board connector is disposed at one end of the board in the second direction, 9. The image forming apparatus according to claim 8, wherein the housing further includes another cover that is separable from the cover and covers the one end of the board in the second direction.

10. 2. The image forming apparatus according to claim 1, further comprising another substrate disposed at a position overlapping the substrate in the first direction.

11. Further comprising a power supply unit for supplying power to the electronic components; a portion of the power supply unit is disposed on one side in the second direction relative to a center of the housing in the second direction, 4. The image forming apparatus according to claim 3, wherein the substrate has a cutout portion formed by cutting out a part of the substrate so as to avoid overlapping with the power supply unit in the first direction.

Images