Image forming apparatus

Abstract

The present disclosure relates to an image forming apparatus including: a main body having an opening and accommodating a photosensitive drum; a door unit connected to the main body and movable between a closed position in which the door unit closes the opening and an open position in which the door unit opens the opening; and a belt unit including a belt configured to be in contact with the photosensitive drum. The belt unit is movable between the inside and the outside of the main body through the opening of the main body with the door unit in the open position. The upper end of the belt is positioned to be lower than the upper end of the door unit in the vertical direction when the belt unit is outside the main body.

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus. Background Art

[0002] Some image forming apparatuses (e.g., printers, copiers, and multifunction printers) have a detachably mounted transfer unit. In some apparatuses, not only the transfer unit but also the cartridge is detachably mounted on a tray that moves between the interior and exterior of the image forming apparatus.

[0003] Japanese Patent Application Laid-Open No. 2010-244018 discloses an image forming apparatus having a tray with a detachably mounted cartridge and a fixing device. The tray can be moved outside a main body of the image forming apparatus through a plurality of openings.

[0004] Japanese Patent Application Laid-Open No. 2015-206897 discloses an image forming device including a tray, a transfer unit, and a fixing device, wherein the tray has a detachably mounted cartridge. The tray unit and the transfer unit described in Japanese Patent Application Laid-Open No. 2015-206897 are capable of moving from the interior to the exterior of the image forming device. More specifically, the fixing device is disposed at one end of a main body of the image forming device. When the transfer unit moves toward the exterior of the main body, the transfer unit moves from the other end of the main body toward one end. When the tray moves toward the exterior of the main body, the tray moves from one end of the main body toward the other end. Summary of the Invention

[0005] In a configuration that allows not only the cartridge tray but also the transfer unit to be pulled out of the image forming apparatus, a user may accidentally touch components in the transfer unit (typically, a transfer member such as an intermediate transfer belt or an electrostatic transfer belt). Such accidental contact by the user may contaminate the components and cause problems, so it is preferable to prevent contamination of the components.

[0006] An object of the present disclosure is to prevent contamination of components in an image forming apparatus equipped with a pull-type transfer unit.

[0007] The present disclosure provides an image forming apparatus, comprising: a main body having an opening and configured to accommodate a photosensitive drum; a door unit connected to the main body and configured to be movable between a closed position in which the door unit closes the opening and an open position in which the door unit opens the opening; a belt unit including a belt configured to contact the photosensitive drum, the belt unit configured to be movable between the interior and exterior of the main body through the opening of the main body when the door unit is in the open position; and a tray unit configured to be movable between the interior and exterior of the main body through the opening of the main body when the door unit is in the open position. The tray unit includes a cassette and a tray, the cassette being detachably mounted on the tray. One of the cassette or the tray contains the photosensitive drum. The door unit is configured to support the belt unit outside the main body when in the open position, and when the belt unit is outside the main body, the upper end of the belt is positioned vertically lower than the upper end of the door unit.

[0008] According to the present disclosure, it is possible to prevent contamination of components in an image forming apparatus having a pull-type transfer unit.

[0009] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 1 is a diagram illustrating the overall configuration of a printer according to Embodiment 1.

[0011] Figure 2 1 is a diagram showing the printer according to Embodiment 1 with the door unit open.

[0012] Figure 3 1 is a diagram showing the printer according to Embodiment 1 with the tray unit pulled out.

[0013] Figure 4 is a diagram showing the printer according to Embodiment 1 with the transfer unit pulled out.

[0014] Figure 5 1 and 2 are diagrams showing the printer according to Embodiment 1 when the transfer unit is pulled out, as viewed from different directions.

[0015] Figure 6 1 is a diagram showing the printer according to Embodiment 2 with the door unit open.

[0016] Figure 7 1 is a diagram showing the printer according to Embodiment 2 with the transfer unit and the tray unit pulled out.

[0017] Figure 8 : is a diagram illustrating a coupling member coupling the tray unit and the transfer unit according to Embodiment 2.

[0018] Figure 9 2 is a diagram illustrating a coupling member coupling the tray unit and the transfer unit according to Embodiment 2.

[0019] Figure 10 : is a diagram illustrating a coupling member coupling the tray unit and the transfer unit according to Embodiment 2. Specific embodiments

[0020] The following describes in detail some embodiments of the present disclosure based on some embodiments with reference to the accompanying drawings. It should be noted that the sizes, materials, shapes, and relative arrangements of the components described in the embodiments should be appropriately modified according to the configuration and various conditions of the device to which the present disclosure is applied. In other words, the following embodiments are not intended to limit the scope of the present disclosure.

[0021] Example 1

[0022] Overall structure

[0023] Will refer to Figure 1 A printer 301 as an image forming apparatus is described. Figure 1 3 is a diagram illustrating the overall configuration of a printer 301 according to this embodiment. In this embodiment, the printer 301 is an electrophotographic color laser beam printer that forms an image on a sheet S as a recording material.

[0024] The printer 301 includes a main body (housing) 301A, a scanner (exposure device) 2, a controller 3, and a door unit (opening and closing member) 20 that can be opened and closed relative to the main body 301A. The printer 301 also includes a sheet feeder 30, a transfer unit 40, a tray unit (moving unit or supporting unit) 50, and a fixing device 80. The main body 301A and the portion connected thereto, including the door unit 20, can be referred to as the "main frame." The main frame comprises the exterior components of the printer 301.

[0025] The main body 301A houses the scanner 2 , the controller 3 , the sheet feeder 30 , the transfer unit 40 , the tray unit 50 , and the fixing device 80 .

[0026] The sheet feeder 30 includes a carrying tray 31 that carries a bundle of sheets S as recording materials, and a supply roller 32. The carrying tray 31 can be pulled out toward the door unit 20 to allow the sheets S to be replenished.

[0027] The tray unit 50 includes a tray (support member or drawer) 51 and cartridges PY, PM, PC, and PK. The tray 51 includes a tray handle 52. The cartridges PY, PM, PC, and PK are detachably mounted on the tray 51.

[0028] Cartridges PY, PM, PC, and PK are independently removable from the tray 51. Cartridges PY, PM, PC, and PK store yellow (Y), magenta (M), cyan (C), and black (K) toners (developers), respectively. Cartridges PY, PM, PC, and PK are identical in construction, differing only in the color of the toner they contain. Therefore, when describing the construction and operation of any one of the cartridges PY, PM, PC, and PK, descriptions of the other cartridges may be omitted. When there is no need to distinguish between the cartridges PY, PM, PC, and PK, they may be simply collectively referred to as "cartridges P." In other words, the tray unit 50 includes a plurality of cartridges P and a tray 51, with the cartridges P being removably mounted on the tray 51.

[0029] In this embodiment, the tray unit 50 includes a plurality of photosensitive drums (image bearing members) 61, a plurality of charging rollers 62 (charging members), and a plurality of developing rollers (developer carrying members) 71. More specifically, the tray unit 50 includes four photosensitive drums 61, four charging rollers 62, and four developing rollers 71. The rotation axes of the photosensitive drums 61, the developing rollers 71, and the charging rollers 62 are parallel to each other.

[0030] The section forming a black (K) image will be referred to as a “black station (first station).” The photosensitive drum 61 , developing roller 71 , and charging roller 62 in the first station will be referred to as a “first photosensitive drum,” a “first developing roller,” and a “first charging roller.”

[0031] The section forming a cyan (C) image will be referred to as a “cyan station (second station).” The photosensitive drum 61 , developing roller 71 , and charging roller 62 in the second station will be referred to as a “second photosensitive drum,” a “second developing roller,” and a “second charging roller.”

[0032] The section where a magenta (M) image is formed will be referred to as a “magenta station (third station).” The photosensitive drum 61 , developing roller 71 , and charging roller 62 in the third station will be referred to as a “third photosensitive drum,” a “third developing roller,” and a “third charging roller.”

[0033] The section forming a yellow (Y) image will be referred to as a “yellow station (fourth station).” The photosensitive drum 61 , developing roller 71 , and charging roller 62 in the fourth station will be referred to as a “fourth photosensitive drum,” a “fourth developing roller,” and a “fourth charging roller.”

[0034] Box PK, PC, PM and PY are installed in black station, cyan station, magenta station and yellow station respectively.In the present embodiment, box PK, PC, PM and PY are referred to as first box, second box, third box and fourth box respectively.Such as first, second, third and fourth such numbering is only for illustrative purpose.

[0035] The photosensitive drum 61, the charging roller 62, and the developing roller 71 may be provided for the cartridge P or the tray 51. In the present embodiment, the cartridge P has the photosensitive drum 61, the charging roller 62, and the developing roller 71.

[0036] The transfer unit 40 is a belt unit that includes a belt 41, a primary transfer roller 42, a cleaner 43, a drive roller 46 for driving the belt 41, and a tension roller (driven roller) 47. The printer 301 in this embodiment is provided with an optical sensor 44 that detects the toner image transferred to the belt 41. In this embodiment, the belt 41, which is arranged below the photosensitive drum 61 and supported by the primary transfer roller 42, is configured to contact the photosensitive drum 61, thereby forming a primary transfer section between the belt 41 and the photosensitive drum 61.

[0037] The printer 301 also includes a secondary transfer roller 45, which contacts the belt 41 to form a secondary transfer section. The secondary transfer section is formed between the belt 41, which is supported by a drive roller 46, and the secondary transfer roller 45. The rotation axes of the primary transfer roller 42, the drive roller 46, the tension roller 47, and the secondary transfer roller 45 are parallel to one another. A registration roller pair 4 is provided before the secondary transfer section in the direction in which the sheet S is conveyed.

[0038] The fixing device 80 includes a fixing unit 81 and a baffle 5. The fixing device 80 is configured to heat the sheet S. In this embodiment, the fixing unit 81 includes a heating unit (heating roller) including a heater and a pressure unit (pressure roller). Components that facilitate conveying the sheet S can be referred to as sheet conveying components. Examples of sheet conveying components include the supply roller 32, the registration roller pair 4, the belt 41, the secondary transfer roller 45, and the fixing unit 81. The direction in which the rotational axes of these components extend can be referred to as the width direction, which is perpendicular to the conveyance direction of the sheet S.

[0039] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 4 The movement of the transfer unit 40 and the tray unit 50 will be described. Figure 2 3 is a diagram showing the printer 301 with the door unit 20 open. Figure 3 1 is a diagram showing the printer 301 when only the tray unit 50 is pulled out. Figure 4 3 is a diagram showing the printer 301 in a state where only the transfer unit 40 is pulled out.

[0040] The transfer unit 40 and the tray unit 50 are movable from the inside to the outside of the main body 301A. In the horizontal direction H, the main body 301A has a first end 1b1 provided with an opening 301A1 and a second end 1b2 on the opposite side.

[0041] The tray unit 50 can be moved through the opening 301A1 to a first inner position within the main body 301A and a first outer position outside the main body 301A. The transfer unit 40 can be moved through the opening 301A1 to a second inner position within the main body 301A and a second outer position outside the main body 301A. The opening 301A1 may include an opening for passing the tray unit 50 and an opening for passing the transfer unit 40. The transfer unit 40 moves from the second inner position to the second outer position to at least cause the belt 41 to be moved, and at least a portion of the belt 41 protrudes outward from the main body 301A.

[0042] The direction in which the tray unit 50 moves from the first inner position to the first outer position will be referred to as the "tray pull-out direction Dd1 (first pull-out direction)", and the direction opposite to the tray pull-out direction Dd1 will be referred to as the "tray mounting direction Da1 (first mounting direction)". The tray pull-out direction Dd1 can be considered to be a direction from the second end 1b2 toward the first end 1b1.

[0043] The direction in which the transfer unit 40 moves from the second inner position to the second outer position will be referred to as the "transfer unit pull-out direction Dd2 (second pull-out direction)," and the direction opposite to the transfer unit pull-out direction Dd2 will be referred to as the "transfer unit mounting direction Da2 (second mounting direction)." The drive roller 46 is disposed downstream of the tension roller 47 along the transfer unit pull-out direction Dd2. The transfer unit pull-out direction Dd2 can be considered to be a direction from the second end 1b2 toward the first end 1b1.

[0044] The tray pull-out direction Dd1 and the tray installation direction Da1 intersect (preferably are perpendicular to) the rotation axis of the photoconductive drum 61. The transfer unit pull-out direction Dd2 and the transfer unit installation direction Da2 intersect (preferably are perpendicular to) the rotation axis of the drive roller 46. The rotation axes of the drive roller 46 and the photoconductive drum 61 are parallel to each other.

[0045] The door unit 20 attached to the main body 301A is movable between a closed position and an open position. Figure 1 As shown, when the door unit 20 is in the closed position (in the closed state), the door unit 20 covers the opening 301A1. Figure 2As shown, when the door unit 20 is in the open position (in the open state), the opening 301A1 is exposed. The closed position is a position in which the door unit 20 closes the opening, and the open position is a position in which the door unit 20 opens the opening. The door unit 20 can move between the closed position and the open position by rotating about a rotation axis 20d located vertically below the opening 301A1.

[0046] like Figure 1 As shown, when the door unit 20 is in the closed position, the door unit 20 covers the fixing device 80 attached to the main body 301A. More specifically, when the door unit 20 is in the closed position, the upper cover portion 20b of the door unit 20 surrounded by the dotted line in the figure is located above the fixing device 80. The upper cover portion 20b of the door unit 20 serves as an exterior portion and provides a function of protecting the belt 41 when the door unit 20 is in the open position. This is one of the features of the present disclosure and will be described in more detail below. The door unit 20 includes an upper cover portion 20b as an upper cover portion to cover at least a portion of the upper surface 301A3 of the main body, and a side cover portion 20c covering at least a portion of the side surface 301A4 of the main body.

[0047] The door unit 20 can be moved to an open position and a closed position when the fixing device 80 is supported on the main body 301A. In other words, the door unit 20 can be moved from the closed position to the open position, thereby moving away from the fixing device 80 supported on the main body 301A. Figure 2 As shown, when the door unit 20 is in the open position, the door unit 20 is positioned away from the fixing device 80 supported on the main body 301A. The transfer unit 40 and the tray unit 50 can be moved from the inside to the outside of the main body 301A through the opening 301A1. Figure 3 and Figure 4 The units are shown after they have been removed.

[0048] In the case where the tray unit 50 is moved out of the main body 301A ( Figure 3 ), allowing the cartridges PY, PM, PC, and PK to be removed from and attached to the tray 51. Thus, the cartridges PY, PM, PC, and PK can be replaced with new ones. In this embodiment, the cartridges P can be removed from and attached to the tray 51 in a direction intersecting (preferably perpendicular) with the direction of the rotation axis of the photosensitive drum 61.

[0049] The cartridges PY, PM, PC, and PK move away from the tray 51 in the opposite direction to the transfer unit 40 when being detached from the tray 51. In the present embodiment, the transfer unit 40 is provided below the tray unit 50. Therefore, the cartridges PY, PM, PC, and PK move upward from the tray 51 when being detached from the tray 51.

[0050] Furthermore, the transfer unit 40 can be removed from the main body 301A independently of the tray unit 50 so as to be replaced with a new transfer unit 40 .

[0051] Image forming operation

[0052] Reference Figure 1 The image forming operation of the printer 301 is described. The controller 3 of the printer 301 starts the image forming operation on the sheet S based on an image signal received from the external host device 400. The external host device 400 is, for example, a personal computer, an image reader, or a facsimile machine.

[0053] During image formation on the sheet S, the tray unit 50 is in the first inner position, the transfer unit 40 is in the second inner position, and the door unit 20 is in the closed position. When the transfer unit 40 is in the second inner position, the belt 41 can contact the photosensitive drum 61. In this state, the tray unit 50 is located above the transfer unit 40.

[0054] A charging voltage is applied to the charging roller 62, and the photosensitive drum 61 starts to rotate. The photosensitive drum 61 is irradiated with laser light from the scanner 2 according to image information, which exposes the surface of the photosensitive drum 61 charged by the charging roller 62. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 61.

[0055] The developing roller 71 carries toner. A developing voltage is applied to the developing roller 71, and the toner supplied from the developing roller 71 develops the electrostatic latent image formed on the photosensitive drum 61. Consequently, a toner image is formed on the photosensitive drum 61. In this embodiment, the electrostatic latent image is developed by the developing roller 71 contacting the photosensitive drum 61. Alternatively, the electrostatic latent image can be developed using the developing roller 71 with a gap between the developing roller 71 and the photosensitive drum 61. When forming a full-color image, the toner image is formed on the corresponding photosensitive drum 61.

[0056] In this embodiment, when the tray unit 50 is in the first internal position, the developing roller 71 is movable between a contact position in which it contacts the photosensitive drum 61 and a separated position in which it is spaced apart from the photosensitive drum 61. More specifically, the main body 301A is provided with a switching mechanism (not shown) for switching the position of the developing roller 71 between the contact position and the separated position. This allows the developing roller 71 to remain separated from the photosensitive drum 61 when no image forming operation is being performed.

[0057] The printer 301 also allows monochrome printing by bringing the developing roller 71 and the photosensitive drum 61 of the cartridge PK into contact with each other when the respective developing rollers 71 and the photosensitive drum 61 of the cartridges PY, PM, and PC are separated from each other. The printer 301 allows full-color printing by bringing the respective photosensitive drums 61 of the cartridges PY, PM, PC, and PK into contact with the belt 41.

[0058] The toner images formed on the respective photosensitive drums 61 are transferred onto the belt 41 by the primary transfer roller 42 in the primary transfer section, and are conveyed to a secondary transfer section formed by the belt 41 and the secondary transfer roller 45 .

[0059] A conveying passage 301c for passing the sheet S toward the fixing device 80 is formed inside the main body 301A. The door unit 20 is provided with a transfer unit support 602 indicated by hatching. Figure 1 As shown, along the width direction ( Figure 1 When viewed from the side (depth direction in the image), the conveying path 301c and the transfer unit support 602 overlap with each other. However, the conveying path through which the sheet S passes and the transfer unit support 602 do not overlap in their lateral positions, so that the transfer unit support 602 does not hinder the conveyance of the sheet S. A duplex printing conveying path 20a is formed in the door unit 20 for allowing the sheet S leaving the fixing device 80 to pass through. The door unit 20 in the closed position covers the conveying path 301c. When the door unit 20 is opened, the conveying path 301c and the duplex printing conveying path 20a are exposed. When the door unit 20 is opened, the transfer unit support 602 is also exposed, as shown in FIG. Figure 2 shown.

[0060] In the sheet feeder 30 , a supply roller 32 separates and sends out one sheet S from the stack of sheets S on the carrying tray 31 at a predetermined timing. The sheet travels toward the secondary transfer section and the fixing device 80 by the registration roller pair 4 .

[0061] In the secondary transfer section, the toner image is transferred from the belt 41 to the sheet S. Any toner not transferred to the sheet S is removed from the belt 41 by a cleaning blade (cleaning member) 43A provided inside the cleaner 43 .

[0062] The sheet S carrying the toner image transferred in the secondary transfer section is conveyed to the fixing device 80. In the fixing device 80, the sheet S is heated and pressurized by the fixing unit 81, thereby fixing the toner image on the sheet S. The sheet S carrying the fixed toner image is conveyed toward the flapper 5 serving as a path switching section.

[0063] The flapper 5 is movable between a paper discharge position and a reversing position. At the paper discharge position, the flapper guides the sheet S from the fixing device 80 toward the paper discharge path 301 d . At the reversing position, the flapper guides the sheet toward the reversing path 301 e .

[0064] During single-sided printing in which an image is formed on one side of a sheet S, the flapper 5 guides the sheet S to a paper discharge path 301 d , thereby discharging the sheet onto a discharge tray 1 f formed on the top of the main body 301A.

[0065] On the other hand, during duplex printing, in which images are formed on both one side and the back side of the sheet S, the flapper 5 guides the sheet S to the reversing path 301e. The sheet S guided to the reversing path 301e is turned over by a pair of reversing rollers 49 to travel in the reverse direction and is conveyed toward the secondary transfer section via the duplex printing conveying path 20a formed in the gate unit 20. After the toner image is transferred to the back side of the sheet S in the secondary transfer section, the sheet S passes through the fixing device 80, is guided by the flapper 5 to the sheet discharge path 301d, and is discharged onto the discharge tray 1f of the main body 301A.

[0066] The moving mechanism of the tray unit and transfer unit and its effects

[0067] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 4 A configuration that allows the tray unit 50 and the transfer unit 40 to be pulled out and its effects are described.

[0068] like Figure 1 As shown, when the tray unit 50 is in its first inner position and the transfer unit 40 is in its second inner position, a portion of the transfer unit 40 (in this embodiment, the cleaner 43) is located downstream of the tray unit 50 in the horizontal direction H, in the direction of movement (Dd1) of the tray unit 50 from the first inner position toward the first outer position. The area of ​​this portion of the transfer unit 40 (in this embodiment, the cleaner 43) located downstream of the tray unit 50 at least partially overlaps with the area where the tray unit 50 is located in the vertical direction V. Therefore, in order to pull the tray unit 50 out of the main body 301A, the tray unit 50 needs to avoid the cleaner 43.

[0069] The tray unit 50 moves out of the main body 301A along the following track. Figure 2 As shown, the tray unit 50 is lifted away from the transfer unit 40 in conjunction with the opening of the door unit 20. The position of the tray unit 50 at this time will be referred to as the "first intermediate position." When the door unit 20 is closed in this state, the tray unit 50 moves downward to the first inner position. When the tray unit 50 is in the first intermediate position, the belt 41 is separated from the photosensitive drum 61.

[0070] Thereafter, the user holds the tray handle 52 and moves the tray unit 50 toward the outside of the main body 301A. Figure 3 As shown, the tray unit 50 is moved out of the main body 301A through the opening 301A1 between the transfer unit 40 and the fixing device 80 .

[0071] Next, a configuration that allows the transfer unit 40 to be pulled out, which is a characteristic of the present disclosure, will be described. Figure 4As shown, the printer 301 in this embodiment allows the transfer unit 40 to be moved out of the main body 301A (the second external position). The transfer unit 40 can be removed from the main body 301A and replaced with a new transfer unit 40. To protect the fragile belt 41 in the transfer unit 40 during replacement, and to enable the user to intuitively identify the rest position of the pulled-out transfer unit 40, the upper end 20b_upper of the upper cover 20b of the door unit 20 is positioned higher than the surface of the belt 41 that contacts the photosensitive drum 61. When the door unit 20 is in its open position, the height of the door unit 20 in the vertical direction V will be referred to as "height Hd." The height Hd in this embodiment is the same as the height of the upper cover 20b of the door unit 20 in the closed position.

[0072] Will refer to Figure 2 、 Figure 4 and Figure 5 This feature is described in more detail. Figure 2 , the transfer unit 40 is in the second inner position. When the transfer unit is in the second inner position, the surface of the belt 41 that contacts the photosensitive drum 61 (indicated as "belt surface 90" in the figure) is positioned lower than the height Hd of the upper cover portion 20b of the door unit 20. The transfer unit abutment member 601, indicated by hatching, is located at one end in the depth direction of the transfer unit 40 so as not to interfere with other components when the transfer unit is pulled out from the second inner position, allowing the transfer unit to be moved to the second outer position. The transfer unit abutment member 601 contacts only the transfer unit support 602. When the transfer unit 40 shifts from the second inner position to the second outer position, it can move horizontally so that the belt 41 is always positioned lower than the height Hd of the upper cover portion 20b of the door unit 20.

[0073] Next, in Figure 4 , the transfer unit 40 is located at the second outer position. When the transfer unit 40 is at the second outer position, the surface 90 of the belt 41 in contact with the photosensitive drum 61 is positioned lower than the height Hd of the upper cover portion 20b of the door unit 20. The belt surface 90 covers and protects the front surface of the belt 41. Figure 5 A definition of "front surface" is provided. When the transfer unit 40 is pulled out, the transfer unit abutment member 601 and the transfer unit support member 602, both indicated by hatching, come into contact with each other and serve as stoppers. The height Hd of the upper cover portion 20b of the door unit 20 is greater than the height of the surface of the belt 41 that contacts the photosensitive drum 61. This allows the user to intuitively recognize that the transfer unit 40 will stop before the upper cover portion 20b.

[0074] Finally, refer to Figure 5 How to protect the front surface of the belt 41 is described. Figure 4 , Figure 53 is a diagram showing the printer 301 when the door unit 20 is open and only the transfer unit 40 is pulled out. Figure 4 The difference is, Figure 5 The printer is shown when viewed from the side where the door unit 20 is opened. Figure 5 1b1 is a view showing the printer 301 along the horizontal direction H from the first end 1b1 toward the second end 1b2. Figure 5 , arrow D indicates the width direction D. As previously referred to Figure 4 As described above, when the transfer unit 40 is pulled out, the surface 90 of the belt 41 that contacts the photosensitive drum 61 in the transfer unit 40 is positioned lower than the upper end 20b_upper (height Hd) of the upper cover portion 20b of the door unit 20. In this configuration, when the user pulls out the transfer unit 40, the upper cover portion 20b is located in front of the front surface 92 (indicated by grid lines) of the belt 41. This reduces the risk of the user coming into contact with the front surface of the belt 41 and prevents the user from accidentally damaging the front surface of the belt 41. The "front surface" here refers to the upstreammost portion of the belt 41 in the direction of movement from the interior to the exterior of the transfer unit 40.

[0075] like Figure 5 As shown, the length of the upper end 20b_upper of the upper cover portion 20b in the width direction D is greater than the length of the belt surface 90. One end and the other end of the upper end 20b_upper in the width direction D are positioned further outward from the belt surface 90. In other words, the belt surface 90 is positioned between one end and the other end of the upper end 20b_upper in the width direction D. Therefore, the belt surface 90 can be more reliably protected. Furthermore, the upper end of the cleaner 43 is positioned higher than the upper end 20b_upper of the upper cover portion 20b. Therefore, the cleaner 43 helps to more reliably protect the belt surface 90.

[0076] Although the image forming apparatus that performs color printing has been described in detail in this embodiment, this is not intended to limit the present disclosure to this apparatus. The image forming apparatus may be configured to perform monochrome printing.

[0077] Example 2

[0078] Embodiment 2 will be described. In Embodiment 2, elements similar to those of the above-described embodiment are given the same reference numerals. Description of elements similar to those of the above-described embodiment may be omitted.

[0079] The difference between this embodiment and the first embodiment is that the transfer unit 740 is also pulled out when the tray unit 750 is pulled out.

[0080] Relationship between the tray unit and the transfer unit

[0081] Will refer to Figure 6 and Figure 7The relationship between the tray unit 750 and the transfer unit 740 , and the movements of the tray unit 750 and the transfer unit 740 are described. Figure 6 2 is an overall view of the printer 701 in this embodiment with the door unit 20 opened. Figure 7 7 is an overall view of the printer 701 in this embodiment when the tray unit 750 and the transfer unit 740 are simultaneously pulled out.

[0082] When the tray unit 750 moves between a first inner position in which an image forming operation is performed on sheets S and a first outer position in which the tray unit allows replacement of the cartridge P, the tray unit 750 passes through a predetermined space. This space through which the tray unit 750 passes when moving from the first inner position to the first outer position will be referred to as a "first space 780." The first space 780 is a moving area of ​​the tray unit 750.

[0083] When the transfer unit 740 moves between the second inner position and the second outer position where the image forming operation on the sheet S is performed, the transfer unit 740 passes through a predetermined space. This space through which the transfer unit 740 passes when moving from the second inner position to the second outer position will be referred to as a "second space 790." The second space 790 is a moving area of ​​the transfer unit 740.

[0084] In this embodiment, at least a portion of the transfer unit 740 overlaps with the first space through which the tray unit 750 passes when the tray unit 750 moves from the first inner position to the first outer position. Alternatively, the transfer unit may partially overlap with the space through which the cartridge P passes. This arrangement allows the size of the main body 701A to be reduced compared to a configuration in which the transfer unit 740 in the second inner position is located outside the first space.

[0085] In the printer 701 of this embodiment, the portion of the transfer unit 740 that overlaps the first space is the cleaner 43 that houses the cleaning member 43A. Alternatively, other portions of the transfer unit 740 may overlap the first space. In this embodiment, the cleaning member 43A of the transfer unit 740 in the second inner position overlaps the first space.

[0086] In other words, the tray unit 750 and the transfer unit 740 satisfy the following relationship. When the tray unit 750 is in its first inner position and the transfer unit 740 is in its second inner position, a portion of the transfer unit 740 (the cleaner 43) is located downstream of the tray unit 750 along the horizontal direction H in the direction of movement of the tray unit 750 from the first inner position toward the first outer position. Furthermore, in the vertical direction V, the region (range) where the portion of the transfer unit 740 (the cleaner 43) is located downstream of the tray unit 750 at least partially overlaps with the region (range) where the tray unit 750 is located.

[0087] As described above, when the transfer unit 740 is in the second inner position, at least a portion of the transfer unit 740 is located within the first space. Therefore, in this embodiment, when the user moves the tray unit 750 from the first inner position to the first outer position relative to the main body 701A, the transfer unit 740 also moves from the second inner position to the second outer position relative to the main body 701A. In other words, when the tray unit 750 and the transfer unit 740 are integrated into a single unit, the tray unit 750 moves from the first inner position to the first outer position, and the transfer unit 740 moves from the second inner position to the second outer position.

[0088] like Figure 7 As shown, when the door unit 20 is opened with the tray unit 750 in its first outer position and the transfer unit 740 in its second outer position, the transfer unit 740 supports the tray unit 750 from below. Furthermore, in this embodiment, the door unit 20 supports the transfer unit 740. In other words, the transfer unit 740 supported by the door unit 20 supports the tray unit 750. This state can be interpreted as the door unit 20 supporting the tray unit 750 via the transfer unit 740.

[0089] Structure for integrally moving the tray unit and transfer unit

[0090] Reference Figure 8 、 Figure 9 and Figure 10 A configuration for integrally moving the tray unit 750 and the transfer unit 740 is described. Figure 8 、 Figure 9 and Figure 10 5 is a diagram for explaining a coupling member (including a lever, a stopper, and a locking member) 53 that couples the tray 751 of the tray unit 750 and the transfer unit 740 .

[0091] The printer 701 according to the present embodiment includes a locking member 53. In the present embodiment, the locking member 53 is provided on the tray 751 of the tray unit 750. The locking member 53 includes a transfer unit locking portion 53A and is rotatable around a rotation center 53B.

[0092] The tray 751 includes a transfer unit coupling portion 51A. The transfer unit 740 includes a drive roller 46, a tension roller 47, and a transfer roller frame 48 that supports the primary transfer roller 42. The transfer roller frame 48 includes a tray coupling groove 48A and a locking member coupling portion 48B.

[0093] The locking member 53 rotates around the rotation center 53B to move between a connection position and a release position, wherein the transfer unit locking portion 53A engages with the locking member connection portion 48B to connect the transfer unit 740 and the tray unit 750 together; and wherein the locking member 53 retracts from the connection position.

[0094] By engaging the transfer unit coupling portion 51A with the tray coupling groove 48A, the movement of the tray unit 750 relative to the transfer unit 740 in the first pull-out direction Dd1 and a direction perpendicular to the first pull-out direction Dd1 is restricted. On the other hand, the movement of the transfer unit 740 relative to the tray unit 750 in the second mounting direction Da2 and a direction perpendicular to the second mounting direction Da2 is restricted.

[0095] The tension roller 47 and the drive roller 46 are provided in a similar configuration at a total of four locations near both ends in the rotation axis direction of the tension roller 47 and the drive roller 46 .

[0096] When the transfer unit locking portion 53A of the locking member 53 in the coupling position engages the locking member coupling portion 48B, the movement of the tray unit 750 relative to the transfer unit 740 in the first mounting direction Da1 is restricted. On the other hand, the movement of the transfer unit 740 relative to the tray unit 750 in the second pulling-out direction Dd2 is restricted.

[0097] The locking member 53 and the locking member coupling portion 48B may also be provided at both ends of the transfer unit 740 in the rotation axis direction of the tension roller 47 .

[0098] That is, the transfer unit 740 and the tray unit 750 are restricted from moving relative to each other by the transfer unit coupling portion 51A engaging with the tray coupling groove 48A and the locking member 53 in the coupled position engaging with the locking member coupling portion 48B. In this state, some play may exist between the transfer unit 740 and the tray unit 750.

[0099] In other words, the transfer unit coupling portion 51A and the locking member 53 function as a tray-side coupling mechanism, while the tray coupling groove 48A and the locking member coupling portion 48B function as a transfer unit-side coupling mechanism. The tray-side coupling mechanism and the transfer unit-side coupling mechanism are coupled together to connect the tray unit 750 and the transfer unit 740, allowing them to move integrally.

[0100] The main body 701A includes Figure 10 When the tray unit 750 is in its first inner position and the transfer unit 740 is in its second inner position, the locking member 53 contacts the lock release portion 1B and is located in the released position. In this state, the transfer unit locking portion 53A is separated from the locking member coupling portion 48B.

[0101] With the locking member 53 in the released position, the tray unit 750, while moving in the first pull-out direction Dd1, causes the transfer unit coupling portion 51A to push the transfer unit 740 in the second pull-out direction Dd2. This causes the transfer unit 740 to move integrally with the tray unit 750 in the second pull-out direction Dd2. The tray unit 750 is moved a predetermined distance in the first pull-out direction Dd1 to cause the locking member 53 to separate from the lock-releasing portion 1B and move to the coupled position to engage with the locking member coupling portion 48B. With the locking member 53 in its coupled position engaged with the locking member coupling portion 48B, the tray unit 750 and the transfer unit 740 move to the first outer position and the second outer position, respectively.

[0102] With the locking member 53 engaged with the locking member coupling portion 48B, the tray unit 750 is moved in the first mounting direction Da1 to cause the locking member 53 to push the transfer unit 740 in the second mounting direction Da2. This causes the transfer unit 740 to move integrally with the tray unit 750 in the second mounting direction Da2.

[0103] With the locking member 53 engaged with the locking member coupling portion 48B, the transfer unit 740 is moved in the second mounting direction Da2 to cause the transfer unit 740 to push the transfer unit coupling portion 51A, thereby pushing the tray unit 750 in the first mounting direction Da1. This causes the tray unit 750 to move integrally with the transfer unit 740 in the first mounting direction Da1.

[0104] When the tray unit 750 and transfer unit 740 are integrally moved into the main body 701A, the lock release portion 1B shifts the locking member 53 to the released position. In this state, when the tray unit 750 moves in the first installation direction Da1, the transfer unit 740 does not move. Therefore, during the closing of the door unit 20, the secondary transfer roller 45, which contacts the transfer unit 740, applies a force to push the transfer unit 740 in the second installation direction Da2, thereby pushing the transfer unit 740 deeper into the main body 701A (the second interior position). In other words, the door unit 20 is able to push the transfer unit 740, thereby moving it to the second interior position. Alternatively, the door unit 20 can push the tray unit 750, thereby moving it to the first interior position.

[0105] On the other hand, when the locking member 53 is in its released position, the transfer unit 740 is allowed to move independently of the tray unit 750 in the second pull-out direction Dd2 from the second inner position toward the second outer position while the tray unit 750 is in its first inner position. Similar to Embodiment 1, the printer 701 in this embodiment allows the transfer unit 740 to be moved out of the main body 701A (the second outer position) while the tray unit 750 is located inside the main body 701A (the first inner position). The transfer unit 740 can be removed from the main body 701A and replaced with a new transfer unit 740.

[0106] In this embodiment, when the tray unit 750 is in the first inner position, the tray unit 750 is positioned relative to the main body 701A independently of the transfer unit 740. When the transfer unit 740 is in the second inner position, the transfer unit 740 is positioned relative to the main body 701A independently of the tray unit 750. This is because it is prioritized to more accurately position each of the transfer unit 740 and the tray unit 750 relative to the main body 701A. To this end, when the tray unit 750 is in the first inner position and the transfer unit 740 is in the second inner position, a slight gap exists between the tray coupling groove 48A and the transfer unit coupling portion 51A.

[0107] Alternatively, there may be no gap between the tray coupling groove 48A and the transfer unit coupling portion 51A, so that the tray unit 750 and the transfer unit 740 can be positioned relative to each other when the tray unit 750 is in the first inner position and the transfer unit 740 is in the second inner position. This allows the transfer unit 740 and the tray unit 750 to be positioned relative to each other more accurately.

[0108] Effects of moving the tray unit and transfer unit integrally

[0109] Reference Figure 6 and Figure 7 The effect of pulling out the tray unit 750 and the transfer unit 740 is described.

[0110] A configuration that allows the transfer unit 740 to be pulled out simultaneously with the tray unit 750 being pulled out, which is a feature of the present embodiment, will be described.

[0111] like Figure 6 As shown, when the door unit 20 is opened, the tray unit 750 is not lifted because there is no need to move the tray unit 750 to the first intermediate position as in the first embodiment.

[0112] The above-described mechanism for integrating the tray unit 750 and the transfer unit 740 allows the user to move the tray unit 750 and the transfer unit 740 outward in the main body 701A by gripping the tray handle 752 .

[0113] The tray unit 750 and the transfer unit 740 are moved out of the main body 701A through the opening 701A1. Figure 7 shown.

[0114] By integrally moving the tray unit 750 and the transfer unit 740, the photosensitive drum 61 can be prevented from being exposed when the tray unit 750 is moved to the first outer position, thereby minimizing the possibility of damaging or contaminating the photosensitive drum 61. In addition, the vulnerable surface of the belt 41 that contacts the photosensitive drum 61 can be protected when replacing the cartridge.

[0115] Furthermore, as in Embodiment 1, further advantageous effects can be obtained by positioning the height Hd of the upper cover portion 20 b of the door unit 20 higher than the surface 90 of the belt 41 in contact with the photosensitive drum 61 .

[0116] Will refer to Figure 6 and Figure 7 This feature is described in more detail. Figure 6 In FIG. 7 , the tray unit 750 is in the first inner position, and the transfer unit 740 is in the second inner position. When the transfer unit 740 is in the second inner position, the surface of the belt 41 in contact with the photosensitive drum 61 is positioned below the height Hd of the upper cover portion 20b of the door unit 20. The transfer unit abutment member 601, indicated by hatching, is located at one end in the depth direction of the transfer unit 740 so as not to interfere with other components when the transfer unit is pulled out of the second inner position, thereby allowing the transfer unit to move to the second outer position. The transfer unit abutment member 601 contacts only the transfer unit support 602.

[0117] When the tray unit 750 and the transfer unit 740 are displaced from the first inner position and the second inner position to the first outer position and the second outer position, respectively, the transfer unit 740 can move horizontally. The surface of the belt 41 (belt surface 90) that contacts the photosensitive drum 61 is always positioned lower than the height Hd of the upper cover portion 20b of the door unit 20.

[0118] Next, in Figure 7 In the figure, the tray unit 750 is in the first outer position, and the transfer unit 740 is in the second outer position. When the transfer unit 740 is in the second outer position, the belt 41 is positioned below the height Hd of the upper cover portion 20b of the door unit 20, so that the front surface of the belt 41 is covered and protected. When the tray unit 750 and transfer unit 740 are pulled out, the transfer unit abutment member 601 and the transfer unit support member 602 (both indicated by hatching) contact each other and serve as stops. The height Hd of the upper cover portion 20b of the door unit 20 is positioned higher than the surface of the belt 41 that contacts the photosensitive drum 61. This allows the user to intuitively recognize that the transfer unit 740 will stop before the upper cover portion 20b.

[0119] Various embodiments of the present disclosure provide the above-described effect of preventing the user from touching the tape 41. Therefore, contamination or damage to the tape 41 is prevented, and the occurrence of problems such as image defects can be minimized.

[0120] The transfer unit in the above embodiment uses an intermediate transfer belt as a transfer member. The present disclosure is not limited to this configuration and can be applied to other types of belt units, such as a belt unit using an electrostatic transfer belt.

[0121] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An image forming apparatus, comprising: a main body having an opening and configured to accommodate a photosensitive drum; a door unit connected to the main body and configured to be movable between a closed position in which the door unit closes the opening and an open position in which the door unit opens the opening; a belt unit including a belt configured to be in contact with the photosensitive drum, the belt unit configured to be movable between the inside and the outside of the main body through the opening of the main body when the door unit is in the open position; as well as a tray unit configured to be movable between the interior and exterior of the main body through the opening of the main body when the door unit is in the open position, the tray unit including a cartridge and a tray, the cartridge being detachably mounted on the tray, one of the cartridge or the tray having the photosensitive drum, wherein the door unit is configured to support the belt unit outside the main body when in the open position, and When the belt unit is outside the main body, an upper end of the belt is positioned vertically lower than an upper end of the door unit.

2. The image forming apparatus according to claim 1, wherein When the belt unit is outside the main body and supported by the door unit in the open position, an upper end of the belt in the belt unit is positioned vertically lower than an upper end of the door unit.

3. The image forming apparatus according to claim 1 or 2, wherein the door unit includes a side cover portion covering at least a portion of a side surface of the main body, and an upper cover portion covering at least a portion of an upper surface of the main body, and the door unit is configured to be movable between the closed position and the open position by rotating about a rotation axis located vertically below the opening, and When the belt unit is outside the main body, the upper end of the belt is positioned lower than the upper end of the upper cover in the vertical direction.

4. The image forming apparatus according to claim 3, further comprising: fixing device, wherein The upper cover portion covers the fixing device when the door unit is in the closed position, and the fixing device is exposed when the door unit is in the open position.

5. The image forming apparatus according to claim 3, wherein The belt has a front surface in an upstream portion in a direction in which the belt unit moves from the inside to the outside of the main body, and the upper cover is configured to always be located upstream of the front surface of the belt when the door unit is in the open position.

6. The image forming apparatus according to claim 1 or 2, wherein When the belt unit moves from the inside to the outside of the main body, the upper end of the belt in the belt unit is positioned to be always lower than the upper end of the door unit in the vertical direction.

7. The image forming apparatus according to claim 1 or 2, wherein When the tray unit moves from the inside to the outside of the main body, the belt unit is configured to move together with the tray unit from the inside to the outside of the main body.

8. The image forming apparatus according to claim 1 or 2, wherein: An upper end of a portion of the belt unit is positioned vertically higher than an upper end of the door unit.

9. The image forming apparatus according to claim 8, wherein The portion of the belt unit is a cleaner configured to clean the belt.

Images