Image forming apparatus

Abstract

To prevent contamination of components in an image forming apparatus in which a transfer unit is movable from inside to outside.SOLUTION: An image forming apparatus includes: an apparatus main body having an opening and accommodating a photosensitive drum; a door unit connected to the apparatus main body and movable between a closed position where it closes the opening and an open position where it opens the opening; and a belt unit having a belt which can contact with the photosensitive drum and being movable between inside and outside of the apparatus main body through the opening with the door unit opened. When the belt unit is outside of the apparatus main body, an upper end of the belt is located lower than an upper end of the door unit in a vertical direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Some image forming devices, such as printers, copiers, and multifunction devices, have a removable transfer unit. In addition to the transfer unit, some also have a removable cartridge mounted on a tray that moves between the inside and outside of the image forming device.

[0003] Patent Document 1 discloses an image forming apparatus including a tray to which cartridges are removably attached and a fixing device. The tray is movable to the outside of the main body of the image forming apparatus through a plurality of openings.

[0004] Furthermore, Patent Document 2 discloses an image forming apparatus including a tray to which a cartridge is removably attached, a transfer unit, and a fixing device. In Patent Document 2, the tray and transfer unit are movable from the inside to the outside of the image forming apparatus. Specifically, the fixing device is disposed at one end of the main body of the image forming apparatus, and when the transfer unit moves to the outside of the main body, the transfer unit moves in a direction from the other end of the main body to the one end. On the other hand, when the tray moves to the outside of the main body, the tray moves in a direction from one end of the main body to the other end. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-244018 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-206897 Summary of the Invention [Problem to be solved by the invention]

[0006] In a configuration in which the transfer unit as well as the cartridge tray can be pulled out from inside to outside the image forming apparatus, there is a possibility that a user may come into contact with components included in the transfer unit (typically, transfer materials such as an intermediate transfer belt or an electrostatic transport belt). Such contact by the user is preferably suppressed because it may cause inconvenience such as soiling of the components.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to prevent parts from becoming soiled in an image forming apparatus in which a transfer unit can be pulled out from the inside to the outside. [Means for solving the problem]

[0008] In order to achieve the above object, an image forming apparatus according to the present invention comprises: a device body that houses a photosensitive drum and has an opening; a door unit connected to the device body and movable between a closed position for closing the opening and an open position for opening the opening; a belt unit having a belt capable of coming into contact with the photosensitive drum, the belt unit being movable between the inside of the apparatus main body and the outside of the apparatus main body through the opening when the door unit is open; Equipped with When the belt unit is located outside the device body, an upper end of the belt is positioned vertically lower than an upper end of the door unit. The image forming apparatus is characterized by the above. [Effects of the Invention]

[0009] According to the present invention, it is possible to prevent parts from becoming soiled in an image forming apparatus in which the transfer unit can be pulled out from the inside to the outside. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating the overall configuration of a printer according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing a printer in a state where a door unit is open according to a first embodiment; [Figure 3] FIG. 10 is a diagram showing a state in which the tray unit of the first embodiment is pulled out. [Figure 4] FIG. 10 is a diagram showing a state in which the transfer unit of the first embodiment is pulled out. [Figure 5] FIG. 10 is a view showing the transfer unit of the first embodiment pulled out from a different direction. [Figure 6] FIG. 10 is a diagram showing a printer according to a second embodiment with the door unit open. [Figure 7] FIG. 1 shows the transfer unit and tray unit of the second embodiment pulled out. [Figure 8] FIG. 10 is a diagram showing a connecting member between the tray and the transfer unit according to the second embodiment. [Figure 9] FIG. 10 is a diagram showing a connecting member between the tray and the transfer unit according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing a connecting member between the tray and the transfer unit according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes in detail exemplary embodiments of the present invention with reference to the drawings. The dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, the scope of the present invention is not limited to the following embodiments.

[0012] [Example 1] [Overall configuration] A printer 301 as an image forming apparatus will be described with reference to Fig. 1. Fig. 1 is a diagram illustrating the overall configuration of the 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.

[0013] Printer 301 has an apparatus main body (housing) 301A, a scanner (exposure device) 2, a control unit 3, and a door unit (opening / closing member) 20 that can be opened and closed relative to apparatus main body 301A. Printer 301 also has a sheet feeding unit 30, a transfer unit 40, a tray unit (moving unit, support unit) 50, and a fixing device 80. The part including apparatus main body 301A and door unit 20 connected thereto can also be called a "main frame." The main frame includes the exterior of printer 301.

[0014] The apparatus main body 301A accommodates the scanner 2, the control unit 3, the sheet feeding unit 30, the transfer unit 40, the tray unit 50, and the fixing device 80.

[0015] The sheet feeding section 30 has a stacking tray 31 for stacking sheets S as recording materials, and a supply roller 32. The stacking tray 31 can be pulled out toward the door unit 20 to replenish the sheets S.

[0016] The tray unit 50 has a tray (support member, drawer) 51 and cartridges PY, PM, PC, and PK. The tray 51 has a tray handle 52. The cartridges PY, PM, PC, and PK are removably attached to the tray 51.

[0017] Each of the cartridges PY, PM, PC, and PK is detachably mounted on the tray 51 independently of the others. The cartridges PY, PM, PC, and PK contain yellow (Y), magenta (M), cyan (C), and black (K) toner (developer), respectively. The cartridges PY, PM, PC, and PK have the same configuration except for the toner colors they contain. Therefore, the configuration and operation of only one of the cartridges PY, PM, PC, and PK will be described, and a description of the others will be omitted. Furthermore, when there is no need to distinguish between the cartridges PY, PM, PC, and PK, the cartridges PY, PM, PC, and PK may be simply referred to as cartridges P. The tray unit 50 can be said to have multiple cartridges P and a tray 51 to which the multiple cartridges P are detachably mounted.

[0018] In this embodiment, the tray unit 50 has a plurality of photosensitive drums (image carriers) 61, a plurality of charging rollers 62 (charging members), and a plurality of developing rollers (developer carriers) 71. Specifically, the tray unit 50 has four photosensitive drums 61, four charging rollers 62, and four developing rollers 71. The rotational axis directions of the photosensitive drums 61, the developing rollers 71, and the charging rollers 62 are parallel to one another.

[0019] The portion where a black (K) image is formed is called the black station (first station), the photosensitive drum 61 of the first station is called the first photosensitive drum, the developing roller 71 is called the first developing roller, and the charging roller 62 is called the first charging roller.

[0020] The portion where a cyan (C) image is formed is called a cyan station (second station), the photosensitive drum 61 of the second station is called a second photosensitive drum, the developing roller 71 is called a second developing roller, and the charging roller 62 is called a second charging roller.

[0021] The portion where a magenta (M) image is formed is called the magenta station (third station), the photosensitive drum 61 of the third station is called the third photosensitive drum, the developing roller 71 is called the third developing roller, and the charging roller 62 is called the third charging roller.

[0022] The portion where a yellow (Y) image is formed is called the yellow station (fourth station), the photosensitive drum 61 of the fourth station is called the fourth photosensitive drum, the developing roller 71 is called the fourth developing roller, and the charging roller 62 is called the fourth charging roller.

[0023] The cartridge PK is installed in the black station, the cartridge PC in the cyan station, the cartridge PM in the magenta station, and the cartridge PY in the yellow station. In this embodiment, the cartridge PK is referred to as the first cartridge, the cartridge PC as the second cartridge, the cartridge PM as the third cartridge, and the cartridge PY as the fourth cartridge. Note that the numbers 1, 2, 3, and 4 are used for convenience of explanation.

[0024] The photosensitive drum 61, the charging roller 62, and the developing roller 71 may be provided in either the cartridge P or the tray 51. In this embodiment, the cartridge P has the photosensitive drum 61, the charging roller 62, and the developing roller 71.

[0025] The transfer unit 40 is a belt unit having a belt 41, a primary transfer roller 42, a cleaning unit 43, a drive roller 46 that drives 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 is disposed below the photosensitive drum 61, is supported by the primary transfer roller 42, and can abut against the photosensitive drum 61 so that a primary transfer portion is formed between the belt 41 and the photosensitive drum 61.

[0026] The printer 301 also has a secondary transfer roller 45 that contacts the belt 41 to form a secondary transfer portion. The secondary transfer portion is formed between the belt 41, which is supported by a drive roller 46, and the secondary transfer roller 45. The rotational axis directions 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 arranged before the secondary transfer portion in the conveying direction of the sheet S.

[0027] The fixing device 80 has a fixing section 81 and a flapper 5. The fixing device 80 is configured to heat the sheet S. In this embodiment, the fixing section 81 includes a heating section (heating roller) including a heater, and a pressure section (pressure roller). The section that conveys the sheet S can be called a sheet conveying section. The supply roller 32, the pair of registration rollers 4, the belt 41, the secondary transfer roller 45, and the fixing section 81 are each an example of a sheet conveying section. The direction of the rotation axes of these members can be called the width direction, which is perpendicular to the conveying direction of the sheet S.

[0028] The movement of the transfer unit 40 and the tray unit 50 will be described using Figures 1, 2, 3, and 4. Figure 2 is a diagram showing the printer 301 with the door unit 20 open. Figure 3 is a diagram showing the printer 301 with the tray unit 50 pulled out by itself. Figure 4 is a diagram showing the printer 301 with the transfer unit 40 pulled out by itself.

[0029] The transfer unit 40 and the tray unit 50 are movable from the inside to the outside of the device main body 301A. In the horizontal direction H, the device main body 301A has a first end 1b1 provided with an opening 301A1 and a second end 1b2 opposite to the first end 1b1.

[0030] The tray unit 50 is movable through the opening 301A1 to a first inner position inside the device body 301A and a first outer position outside the device body 301A. The transfer unit 40 is movable through the opening 301A1 to a second inner position inside the device body 301A and a second outer position outside the device body 301A. The opening 301A1 may include an opening through which the tray unit 50 passes and an opening through which the transfer unit 40 passes. When the transfer unit 40 moves from the second inner position to the second outer position, at least the belt 41 is moved, and at least a part of the belt 41 protrudes from the device body 301A toward the outside of the device body 301A.

[0031] The direction in which the tray unit 50 moves from the first inner position to the first outer position is called the tray pull-out direction Dd1 (first pull-out direction), and the direction opposite to the tray pull-out direction Dd1 is called the tray installation direction Da1 (first installation direction). The tray pull-out direction Dd1 can be said to be the direction from the second end 1b2 toward the first end 1b1.

[0032] The direction in which the transfer unit 40 moves from the second inner position to the second outer position is called the transfer pull-out direction Dd2 (second pull-out direction), and the direction opposite to the transfer pull-out direction Dd2 is called the transfer attachment direction Da2 (second attachment direction). In the transfer pull-out direction Dd2, the drive roller 46 is disposed downstream of the tension roller 47. The transfer pull-out direction Dd2 can be said to be the direction from the second end 1b2 toward the first end 1b1.

[0033] The tray pull-out direction Dd1 and the tray mounting direction Da1 are directions that intersect (preferably perpendicular to) the rotational axis direction of the photosensitive drum 61. The transfer pull-out direction Dd2 and the transfer mounting direction Da2 are directions that intersect (preferably perpendicular to) the rotational axis direction of the drive roller 46. The rotational axis direction of the drive roller 46 is parallel to the rotational axis direction of the photosensitive drum 61.

[0034] The door unit 20 attached to the device main body 301A is movable between a closed position and an open position. As shown in FIG. 1, when the door unit 20 is in the closed position (closed state of the door unit 20), the door unit 20 covers the opening 301A1. As shown in FIG. 2, when the door unit 20 is in the open position (open state of the door unit 20), the opening 301A1 is exposed. The closed position of the door unit 20 is a closed position where the opening is closed, and the open position is an open position where the opening is open. The door unit 20 is movable between the closed position and the open position by rotating about a rotation axis 20d located below the opening 301A1 in the vertical direction.

[0035] As shown in FIG. 1, when the door unit 20 is in the closed position, the door unit 20 covers the fixing device 80 attached to the apparatus 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, which is surrounded by a dotted line, is located above the fixing device 80. The upper cover portion 20b of the door unit 20 functions as a part of the exterior and also has the function of protecting the belt 41 when the door unit 20 is in the open position, which is a feature of the present invention. Details will be described later. The door unit 20 includes the upper cover portion 20b as an upper surface cover portion that covers at least a part of the upper surface 301A3 of the apparatus main body, and a side cover portion 20c that covers at least a part of the side surface 301A4 of the apparatus main body.

[0036] The door unit 20 can move between an open position and a closed position while the fixing device 80 is supported by the apparatus main body 301A. In other words, the door unit 20 moves from the closed position to the open position so as to move away from the fixing device 80 supported by the apparatus main body 301A. Therefore, as shown in FIG. 2, when the door unit 20 is in the open position, the door unit 20 is away from the fixing device 80 supported by the apparatus main body 301A. The transfer unit 40 and the tray unit 50 can move from the inside to the outside of the apparatus main body 301A through the opening 301A1, and after moving, they are in the states shown in FIGS. 3 and 4.

[0037] With the tray unit 50 moved to the outside of the apparatus main body 301A (FIG. 3), it is possible to remove the cartridges PY, PM, PC, and PK from the tray 51 and to attach the cartridges PY, PM, PC, and PK to the tray 51. This allows the cartridges PY, PM, PC, and PK to be replaced with new cartridges PY, PM, PC, and PK. In this embodiment, the cartridge P is detachable from the tray 51 in a direction intersecting (preferably perpendicular to) the rotation axis of the photosensitive drum 61.

[0038] The cartridges PY, PM, PC, and PK are removed from the tray 51 by moving toward the opposite side of the transfer unit 40 relative to the tray 51. In this embodiment, the transfer unit 40 is disposed below the tray unit 50. Therefore, the cartridges PY, PM, PC, and PK are removed from the tray 51 by moving upward relative to the tray 51.

[0039] Furthermore, the transfer unit 40 can be removed from the apparatus main body 301A independently of the tray unit 50, and can be replaced with a new transfer unit 40.

[0040] [Image formation operation] 1, the image forming operation of the printer 301 will be described. The control unit 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.

[0041] When an image is formed on the sheet S, the tray unit 50 is located at the first inner position, the transfer unit 40 is located at the second inner position, and the door unit 20 is located at the closed position. When the unit 40 is in the second inner position, the belt 41 can come into contact with the photosensitive drum 61. At this time, the tray unit 50 is located above the transfer unit 40.

[0042] A charging voltage is applied to the charging roller 62, causing the photosensitive drum 61 to rotate. A laser corresponding to image information is irradiated from the scanner 2 onto the photosensitive drum 61, exposing the surface of the photosensitive drum 61 that has been 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.

[0043] The developing roller 71 carries toner. A developing voltage is applied to the developing roller 71, and the electrostatic latent image formed on the photosensitive drum 61 is developed with toner supplied from the developing roller 71, forming a toner image on the surface of the photosensitive drum 61. In this embodiment, the developing roller 71 develops the electrostatic latent image while in contact with the photosensitive drum 61, but the developing roller 71 may also develop the electrostatic latent image while there is a gap between the developing roller 71 and the photosensitive drum 61. When a full-color image is formed, a toner image of each color is formed on each photosensitive drum 61.

[0044] In this embodiment, when the tray unit 50 is in the first inner position, the developing roller 71 is movable between a contact position where it contacts the photosensitive drum 61 and a spaced position where it is spaced from the photosensitive drum 61. Specifically, a switching device (not shown) provided in the apparatus main body 301A switches between a state where the developing roller 71 is in the contact position and a state where the developing roller 71 is in the spaced position. This allows the developing roller 71 to be spaced from the photosensitive drum 61 when no image formation operation is being performed.

[0045] The printer 301 can perform monochrome printing when the developing roller 71 corresponding to the cartridge PK is in contact with the photosensitive drum 61 and the developing rollers 71 corresponding to the cartridges PY, PM, and PC are spaced apart from the photosensitive drums 61. The printer 301 can also perform full-color printing when the photosensitive drums 61 corresponding to the cartridges PY, PM, PC, and PK are in contact with the belt 41.

[0046] The toner images formed on each photosensitive drum 61 are transferred onto the belt 41 by the primary transfer roller 42 at the primary transfer section, and then transported toward the secondary transfer section formed by the belt 41 and the secondary transfer roller 45.

[0047] Meanwhile, the apparatus main body 301A is provided with a transport path 301c through which the sheet S heading toward the fixing device 80 passes. The door unit 20 is provided with a transfer unit support member 602 indicated by diagonal lines. As shown in FIG. 1, the transport path 301c and the transfer unit support member 602 overlap in the width direction (depth direction in FIG. 1). However, since the position of the transport path through which the sheet S passes and the position of the transfer unit support member 602 do not overlap in the width direction, the transfer unit support member 602 does not interfere with the transport of the sheet S. The door unit 20 also has a duplex transport path 20a through which the sheet S passes after passing through the fixing device 80. The door unit 20 covers the transport path 301c in the closed position. When the door unit 20 is opened, the transport path 301c and the duplex transport path 20a are exposed. When the door unit 20 is opened, the transfer unit support member 602 and the transfer unit support member 602 are also exposed, as shown in FIG. 2.

[0048] In the sheet feeding section 30, one sheet S is separated and fed from the sheets S stacked on the stacking tray 31 by the supply roller 32 at a predetermined timing, and is transported through a pair of registration rollers 4 toward the secondary transfer section and fixing device 80.

[0049] In the secondary transfer portion, the toner image is transferred from the belt 41 to the sheet S. The toner that has not been transferred to the sheet S is removed by a cleaning blade (cleaning member) provided in the cleaning portion 43. It is removed from the belt 41 by 43A.

[0050] The sheet S onto which the toner image has been transferred in the secondary transfer unit is transported toward a fixing device 80. In the fixing device 80, the sheet S is heated and pressurized in a fixing unit 81, and the toner image is fixed onto the sheet S. The sheet S onto which the toner image has been fixed is transported toward a flapper 5 serving as a path switching unit.

[0051] The flapper 5 is movable between a paper discharge position where the sheet S that has passed through the fixing device 80 is guided toward a paper discharge path 301d and a reversing position where the sheet S is guided toward a reversing path 301e.

[0052] When single-sided printing is performed, in which an image is formed on one side of the sheet S, the sheet S is guided to the paper discharge path 301d by the flapper 5 and discharged onto a discharge tray 1f formed on the top of the apparatus main body 301A.

[0053] On the other hand, when double-sided printing is performed, in which images are printed on both sides of the sheet S, the sheet S is guided to the reversing path 301e by the flapper 5. After the sheet S is guided to the reversing path 301e, the conveying direction of the sheet S is reversed by the reversing roller pair 49, and the sheet S is conveyed toward the secondary transfer unit through the double-sided conveying path 20a formed in the door unit 20. After the toner image is transferred to the back side of the sheet S in the secondary transfer unit, the sheet S passes through the fixing device 80, is guided by the flapper 5 to the paper discharge path 301d, and is discharged onto the discharge tray 1f of the apparatus main body 301A.

[0054] [Configuration and effect for moving the tray unit and transfer unit] The configuration and effect of removing the tray unit 50 and the transfer unit 40 will be described with reference to FIGS. 1, 2, 3, and 4. FIG.

[0055] 1, with the tray unit 50 in the first inner position and the transfer unit 40 in the second inner position, in the movement direction (Dd1) in which the tray unit 50 moves from the first inner position to the first outer position, a part of the transfer unit 40 (the cleaning unit 43 in this embodiment) is downstream of the tray unit 50 in the horizontal direction H. In addition, in the vertical direction V, the area in which the part of the transfer unit 40 (the cleaning unit 43) downstream of the tray unit 50 is disposed at least partially overlaps with the area in which the tray unit 50 is disposed. Therefore, to pull the tray unit 50 out of the apparatus main body 301A, it is necessary to move it away so as not to interfere with the cleaning unit 43.

[0056] The trajectory of the tray unit 50 moving out of the apparatus main body 301A will now be described. As shown in FIG. 2, in conjunction with the opening of the door unit 20, the tray unit 50 is lifted away from the transfer unit 40. The position of the tray unit 50 at this time is called the first intermediate position. When the door unit 20 is closed in this state, the tray unit 50 descends and moves to the first inner position. When the tray unit 50 is in the first intermediate position, the belt 41 is away from the photosensitive drum 61.

[0057] Thereafter, the user grasps the tray handle 52 and moves the tray unit 50 toward the outside of the apparatus main body 301A. As shown in Fig. 3, the tray unit 50 moves to the outside of the apparatus main body 301A through the opening 301A1 between the transfer unit 40 and the fixing device 80.

[0058] Next, the drawer structure of the transfer unit 40, which is a feature of the present invention, will be described. In the printer 301 of this embodiment, as shown in FIG. 4, the transfer unit 40 can be moved to the outside of the device main body 301A (second outside position). The transfer unit 40 can be removed from the device main body 301A and replaced with a new transfer unit 40. When replacing In order to protect the belt 41 of the transfer unit 40, which is easily damaged, and to allow the user to intuitively understand the stopping position of the pulled-out transfer unit 40, the upper end 20b_upper of the upper cover part 20b of the door unit 20 is higher than the surface of the belt 41 that contacts the photosensitive drum 61. When the door unit 20 is in the open position, the height of the door unit 20 in the vertical direction V is referred to as height Hd. In this embodiment, height Hd is the same as the height of the upper cover part 20b of the door unit 20 in the closed position.

[0059] This will be described in detail using Figures 2, 4, and 5. First, in Figure 2, the transfer unit 40 is in the second inner position. When the transfer unit 40 is in the second inner position, the belt surface ("belt surface 90" in the figure) where the belt 41 contacts the photosensitive drum 61 is lower than the height Hd of the upper cover portion 20b of the door unit 20. The transfer unit abutting member 601, indicated by diagonal lines, is located at the end of the transfer unit 40 in the depth direction, and when the transfer unit 40 is pulled out from the second inner position, it can be moved to the second outer position without interfering with other members. The transfer unit abutting member 601 comes into contact with the transfer unit support member 602. When the transfer unit 40 is moved from the second inner position to the second outer position, the transfer unit 40 can be moved horizontally, and the belt 41 is always lower than the height Hd of the upper cover portion 20b of the door unit 20.

[0060] Next, in Figure 4, the transfer unit 40 is in the second outer position. When the transfer unit 40 is in the second outer position, the belt surface 90 that contacts the photosensitive drum 61 of the belt 41 is lower than the height Hd of the upper cover portion 20b of the door unit 20, and covers and protects the front surface of the belt 41. The definition of the "front surface" will be explained later in Figure 5. When the transfer unit 40 is pulled out, a transfer unit abutment member 601, shown with diagonal lines, comes into contact with a transfer unit support member 602, also shown with diagonal lines, and acts as a stopper. Because the height Hd of the upper cover portion 20b of the door unit 20 is higher than the surface of the belt 41 that contacts the photosensitive drum 61, the user can intuitively understand that the transfer unit 40 will stop in front of the upper cover portion 20b.

[0061] Finally, protection of the front surface of the belt 41 will be described using FIG. 5. Like FIG. 4, FIG. 5 illustrates the printer 301 with the door unit 20 open and the transfer unit 40 pulled out by itself. However, unlike FIG. 4, the perspective is different, as the view is from the side with the door unit 20 open. FIG. 5 is a view viewed in the horizontal direction H, looking from the first end 1b1 toward the second end 1b2 of the printer 301. In FIG. 5, the direction indicated by arrow D is the width direction D. As described above with reference to FIG. 4, when the transfer unit 40 is pulled out, the belt surface 90 of the belt 41 of the transfer unit 40 that contacts the photosensitive drum 61 is below the upper end 20b_upper (height Hd) of the upper cover portion 20b of the door unit 20. With this configuration, when a user pulls out the transfer unit 40, the upper cover portion 20b is located in front of the front surface 92 of the belt 41 (the surface on which the grid lines are drawn). This reduces the risk of the user coming into contact with the front surface of belt 41, and prevents unintended damage to the front surface of belt 41. Note that the "front surface" here refers to the portion of belt 41 that is located most upstream in the direction in which transfer unit 40 moves from the inside to the outside of device main body 301A.

[0062] As shown in FIG. 5 , the length of the upper end 20b_upper of the upper cover part 20b in the width direction D is longer than the length of the belt surface 90. Furthermore, one end and the other end of the upper end 20b_upper are located outside the belt surface 90 in the width direction D. In other words, the belt surface 90 is located 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 protected more reliably. Furthermore, the position of the upper end of the cleaning part 43 is higher than the position of the upper end 20b_upper of the upper cover part 20b. Therefore, the cleaning part 43 can protect the belt surface 90 more reliably.

[0063] In this embodiment, the image forming apparatus for color printing has been described in detail. This is not intended to be limiting, and an image forming apparatus that performs monochrome printing may also be used.

[0064] [Example 2] A second embodiment will be described. In the second embodiment, the same components as those described in the above-described embodiments are designated by the same reference numerals as those used in the respective embodiments. Also, the description of the same components as those in the respective embodiments may be omitted.

[0065] This embodiment differs from the first embodiment in that when the tray unit 750 is pulled out, the transfer unit 740 is also pulled out at the same time.

[0066] [Relationship between the tray unit and the transfer unit] 6 and 7, the relationship between the tray unit 750 and the transfer unit 740 and the movement of the transfer unit 740 and the tray unit 750 will be described. Fig. 6 is an overall view of the printer 701 in this embodiment with the door unit 20 open. Fig. 7 is an overall view of the printer 701 in this embodiment with the tray unit 750 and the transfer unit 740 pulled out at the same time.

[0067] The tray unit 750 passes through a predetermined space when moving between a first inner position where an image forming operation is performed on the sheet S and a first outer position where replacement of the cartridge P is permitted. In this way, the space through which the tray unit 750 passes when moving from the first inner position to the first outer position is called a first space 780. The first space 780 is a space through which the tray unit 750 moves.

[0068] The transfer unit 740 passes through a predetermined space when moving between the second inner position where an image forming operation is performed on the sheet S and the second outer position. The space through which the transfer unit 740 passes when moving from the second inner position to the second outer position is called the second space 790. The second space 790 is the movement space of the transfer unit 740.

[0069] 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, but it may also be disposed so as to overlap with the space through which the cartridge P passes. This allows the apparatus main body 701A to be made smaller than in a configuration in which the transfer unit 740 at the second inner position is positioned outside the first space.

[0070] In the printer 701 of this embodiment, the part of the transfer unit 740 that overlaps with the first space is the cleaning section 43 that houses the cleaning member 43A. However, other parts of the transfer unit 740 may overlap with the first space. In this embodiment, the cleaning member 43A of the transfer unit 740 that is in the second inner position overlaps with the first space.

[0071] It can be said that the tray unit 750 and the transfer unit 740 satisfy the following relationship: With the tray unit 750 in the first inner position and the transfer unit 740 in the second inner position, in the movement direction in which the tray unit 750 moves from the first inner position to the first outer position, a part of the transfer unit 740 (cleaning unit 43) is downstream of the tray unit 750 in the horizontal direction H. In addition, in the vertical direction V, the area (range) in which the part of the transfer unit 740 (cleaning unit 43) downstream of the tray unit 750 is arranged at least partially overlaps with the area (range) in which the tray unit 750 is arranged.

[0072] As described above, when the transfer unit 740 is in the second inner position, at least a part of the transfer unit 740 is located inside 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 apparatus main body 701A, At the same time, the transfer unit 740 is also moved from the second inner position to the second outer position relative to the apparatus main body 701A. That is, with the transfer unit 740 and the tray unit 750 integrated together, 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.

[0073] 7, when the door unit 20 is open, the tray unit 750 is in the first outer position, and the transfer unit 740 is in the second outer position, the transfer unit 740 supports the tray unit 750 from below the tray unit 750. 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. In this state, it can also be said that the door unit 20 supports the tray unit 750 via the transfer unit 740.

[0074] [Configuration for moving the tray unit and transfer unit together] The configuration for integrally moving the tray unit 750 and the transfer unit 740 will be described with reference to Figures 8, 9, and 10. Figures 8, 9, and 10 are diagrams illustrating a connecting member (lever, stopper, locking member) 53 that connects the tray 51 of the tray unit 50 and the transfer unit 740.

[0075] The printer 701 according to this embodiment has a locking member 53. In this embodiment, the locking member 53 is provided on a tray 751 of a tray unit 750. The locking member 53 has a transfer locking portion 53A and is rotatable around a rotation center 53B.

[0076] The tray 751 has a transfer connection portion 51A. The transfer unit 40 has a transfer frame 48 that supports a drive roller 46, a tension roller 47, and a primary transfer roller 42, and the transfer frame 48 has a tray connection groove 48A and a lock connection portion 48B.

[0077] The locking member 53 rotates around the rotation center 53B, whereby the transfer locking portion 53A engages with the lock connecting portion 48B, and the locking member 53 can move to a connecting position where the transfer unit 740 and the tray unit 750 are connected, and to a release position where the transfer unit 740 is retracted from the connecting position.

[0078] By engaging the transfer connecting portion 51A with the tray connecting groove 48A, the tray unit 750 is restricted from moving in the first pull-out direction Dd1 and in a direction perpendicular to the first pull-out direction Dd1 relative to the transfer unit 740. On the other hand, the transfer unit 740 is restricted from moving in the second mounting direction Da2 and in a direction perpendicular to the second mounting direction Da2 relative to the tray unit 750.

[0079] Similar structures are provided at four locations in total: near both ends of the tension roller 47 in the direction of its rotation axis, and near both ends of the drive roller 46 in the direction of its rotation axis.

[0080] When the transfer lock portion 53A of the lock member 53 in the coupled position engages with the lock coupling portion 48B, the tray unit 750 is restricted from moving in the first mounting direction Da1 relative to the transfer unit 740. On the other hand, the transfer unit 740 is restricted from moving in the second pull-out direction Dd2 relative to the tray unit 750.

[0081] The locking member 53 and the locking connecting portion 48B may also be provided at both ends of the transfer unit 740 in the direction of the rotation axis of the tension roller 47.

[0082] That is, the transfer connecting portion 51A is engaged with the tray connecting groove 48A, and the locking member 51A is in the connecting position. When the lock connecting portion 53 is engaged with the lock connecting portion 48B, the transfer unit 740 and the tray unit 50 are restricted from moving relative to each other. In this state, there may be play between the transfer unit 740 and the tray unit 750.

[0083] In other words, it can be said that the transfer connecting portion 51A and the locking member 53 function as a tray-side connecting device, and the tray connecting groove 48A and the lock connecting portion 48B function as a transfer-side connecting device. By connecting the tray-side connecting device and the transfer-side connecting device, the tray unit 750 and the transfer unit 740 are connected, and the tray unit 750 and the transfer unit 740 move integrally.

[0084] 10, the apparatus main body 701A has an unlocking portion 1B. When the tray unit 750 is in the first inner position and the transfer unit 740 is in the second inner position, the locking member 53 is in contact with the unlocking portion 1B and is in the unlocked position. In this state, the transfer locking portion 53A is separated from the lock connecting portion 48B.

[0085] When the tray unit 750 is moved in the first pull-out direction Dd1 with the locking member 53 in the released position, the transfer unit 740 is pushed in the second pull-out direction Dd2 by the transfer connecting portion 51A. As a result, the transfer unit 740 is also moved integrally with the tray unit 750 in the second pull-out direction Dd2. When the tray unit 750 moves a predetermined distance in the first pull-out direction Dd1, the locking member 53 separates from the lock releasing portion 1B, moves to the connected position, and engages with the lock connecting portion 48B. With the locking member 53 in the connected position and engaged with the lock connecting portion 48B, the tray unit 750 is moved to the first outer position, and the transfer unit 740 is moved to the second outer position.

[0086] When the tray unit 750 is moved in the first mounting direction Da1 with the locking member 53 engaged with the lock connecting portion 48B, the transfer unit 740 is pushed in the second mounting direction Da2 by the locking member 53. As a result, the transfer unit 740 is also moved integrally with the tray unit 750 in the second mounting direction Da2.

[0087] When the transfer unit 740 is moved in the second mounting direction Da2 with the lock member 53 engaged with the lock connecting portion 48B, the transfer unit 740 pushes the transfer connecting portion 51A, and the tray unit 750 is pushed in the first mounting direction Da1. As a result, the tray unit 750 is also moved integrally with the transfer unit 740 in the first mounting direction Da1.

[0088] When the tray unit 750 and the transfer unit 740 are moved integrally toward the inside of the apparatus main body 701A, the lock member 53 is moved to the unlocking position by the lock release section 1B. In this state, even if the tray unit 750 is moved in the first mounting direction Da1, the transfer unit 740 does not move. Therefore, during the process of closing the door unit 20, the force of the secondary transfer roller 45 contacting the transfer unit 740 pushes the transfer unit 740 in the second mounting direction Da2 and pushes it to the back of the apparatus main body 701A (to the second inner position). In other words, the door unit 20 can push the transfer unit 740 so that the transfer unit 740 is located at the second inner position. Alternatively, the door unit 20 may push the tray unit 750 so that the tray unit 750 is located at the first inner position.

[0089] On the other hand, when the transfer unit 740 is moved in the second drawing direction Dd2 with the locking member 53 in the release position and the tray unit 750 in the first inner position, the transfer unit 740 can move from the second inner position to the second outer position independently of the tray unit 750. In the printer 701 of this embodiment, as in the first embodiment, with the tray unit 750 positioned inside the device main body 701A (first inner position), the transfer unit 740 can be moved to the outside of the device main body 701A (second outer position). The transfer unit 740 can be removed from the device main body 701A and replaced with a new transfer unit 740.

[0090] In this embodiment, when the tray unit 750 is in the first inner position, the tray unit 750 is positioned relative to the apparatus main body 701A independently of the transfer unit 740. Furthermore, when the transfer unit 740 is in the second inner position, the transfer unit 740 is positioned relative to the apparatus main body 701A independently of the tray unit 750. This is because priority is given to accurately positioning each of the transfer unit 740 and the tray unit 750 relative to the apparatus main body 701A. Therefore, when the tray unit 750 is in the first inner position and the transfer unit 740 is in the second inner position, a slight clearance is provided between the tray connecting groove 48A and the transfer connecting portion 51A.

[0091] The clearance between the tray connecting groove 48A and the transfer connecting portion 51A may be eliminated 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. In this case, the transfer unit 740 and the tray unit 750 can be positioned relative to each other with high precision.

[0092] [Effect of moving the tray unit and transfer unit together] The effect of removing the tray unit 750 and the transfer unit 740 will be described with reference to FIGS.

[0093] A feature of this embodiment, in which the transfer unit 740 is simultaneously pulled out when the tray unit 750 is pulled out, will be described.

[0094] As shown in FIG. 6, when the door unit 20 is open, unlike in the first embodiment, there is no need to move the tray unit 750 to the first intermediate position, and therefore the tray unit 750 is not raised.

[0095] The mechanism that integrates the tray unit 750 and the transfer unit 740 described above allows the user to grasp the tray handle 752 and move the tray unit 750 and the transfer unit 740 toward the outside of the apparatus main body 701A.

[0096] As shown in FIG. 7, the tray unit 750 and the transfer unit 740 move to the outside of the apparatus main body 701A through the opening 701A1.

[0097] By moving the tray unit 750 and the transfer unit 740 together, it is possible to prevent the photosensitive drum 61 from being exposed when the tray unit 750 moves to the first outer position, and to prevent the photosensitive drum 61 from being scratched or soiled. Furthermore, it is possible to protect the surface of the belt 41 that comes into contact with the photosensitive drum 61, which is easily damaged when replacing the cartridge.

[0098] In addition, as in the first embodiment, the height Hd of the upper cover portion 20b of the door unit 20 is higher than the belt surface 90 where the belt 41 contacts the photosensitive drum 61, which provides an additional effect.

[0099] This will be described in detail with reference to Figures 6 and 7. First, in Figure 6, 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 that contacts the photosensitive drum 61 is lower than the height Hd of the upper cover part 20b of the door unit 20. The transfer unit abutment member 601 shown with diagonal lines is located at the end of the transfer unit 740 in the depth direction, and is pulled out from the second inner position. When the transfer unit abutting member 601 is to be moved to the second outer position without interfering with other members, the transfer unit abutting member 601 comes into contact with the transfer unit supporting member 602.

[0100] When the tray unit 750 and the transfer unit 740 are moved from the first and second inner positions to the first and second outer positions, the transfer unit 740 can be moved horizontally, and the surface of the belt 41 that contacts the photosensitive drum 61 (belt surface 90) is always lower than the height Hd of the upper cover part 20b of the door unit 20.

[0101] 7, the tray unit 750 and the transfer unit 740 are in the first and second outer positions. When the transfer unit 740 is in the second outer position, the belt 41 is lower than the height Hd of the upper cover portion 20b of the door unit 20, covering and protecting the front of the belt 41. When the tray unit 750 and the transfer unit 740 are pulled out, the transfer unit abutment member 601, shown with diagonal lines, and the transfer unit support member 602, also shown with diagonal lines, come into contact and act as a stopper. Because the height Hd of the upper cover portion 20b of the door unit 20 is higher than the surface of the belt 41 that contacts the photosensitive drum 61, the user can intuitively understand that the transfer unit 740 will stop in front of the upper cover portion 20b.

[0102] According to each embodiment of the present invention, it is possible to prevent the user from coming into contact with the belt 41, thereby preventing the belt 41 from becoming dirty or damaged, and preventing problems such as poor image quality.

[0103] The transfer unit in the above embodiment uses an intermediate transfer belt as the transfer material, but the present invention is not limited to this and may be applied to a belt unit that uses, for example, an electrostatic transport belt.

[0104] [Configuration 1] a device body that houses a photosensitive drum and has an opening; a door unit connected to the device body and movable between a closed position for closing the opening and an open position for opening the opening; a belt unit having a belt capable of coming into contact with the photosensitive drum, the belt unit being movable between the inside of the apparatus main body and the outside of the apparatus main body through the opening when the door unit is open; Equipped with When the belt unit is located outside the device body, an upper end of the belt is positioned vertically lower than an upper end of the door unit. An image forming apparatus characterized by: [Configuration 2] the door unit is configured to support the belt unit outside the apparatus body when in the open position; when the belt unit is located outside the apparatus main body and supported by the door unit in the open position, an upper end of the belt of the belt unit is positioned lower in the vertical direction than an upper end of the door unit; 2. The image forming apparatus according to claim 1, [Configuration 3] the door unit includes a side cover portion that covers at least a portion of a side surface of the device body and an upper cover portion that covers at least a portion of an upper surface of the device body, and is rotatable about a rotation axis that is located below the opening in the vertical direction to move between the closed position and the open position; When the belt unit is located outside the device body, an upper end of the belt is positioned lower in the vertical direction than an upper end of the top cover. 3. The image forming apparatus according to claim 1, wherein: [Configuration 4] further comprising a fixing device; When the door unit is in the closed position, the upper cover portion covers the fixing device, and when the door unit is in the open position, the fixing device is exposed. 4. The image forming apparatus according to configuration 3. [Configuration 5] When the door unit is in the open position, the upper cover portion is always located upstream of the front surface of the belt in the direction in which the belt unit moves from the inside to the outside of the device body. 5. The image forming apparatus according to configuration 3 or 4. [Configuration 6] When the belt unit moves from the inside of the apparatus body to the outside of the apparatus body, the upper end of the belt of the belt unit is always positioned lower in the direction than the upper end of the door unit. 6. The image forming apparatus according to any one of configurations 1 to 5. [Configuration 7] The image forming apparatus of any one of configurations 1 to 6 further comprises a tray unit that is movable between the inside of the apparatus main body and the outside of the apparatus main body through the opening when the door unit is in the open position, the tray unit including a cartridge and a tray to which the cartridge is removably attached, one of the cartridge and the tray having the photosensitive drum. [Configuration 8] When the tray unit moves from inside the device body to outside the device body, the belt unit also moves from inside the device body to outside the device body. 8. The image forming apparatus according to configuration 7. [Explanation of symbols]

[0105] 20: Door unit, 40: Transfer unit, 41: Belt, 301: Printer, 301A: Device body, 301A1: Opening

Claims

1. a device body that houses a photosensitive drum and has an opening; a door unit connected to the device body and movable between a closed position for closing the opening and an open position for opening the opening; a belt unit having a belt capable of coming into contact with the photosensitive drum, the belt unit being movable between the inside of the apparatus main body and the outside of the apparatus main body through the opening when the door unit is open; Equipped with When the belt unit is located outside the device body, an upper end of the belt is positioned vertically lower than an upper end of the door unit. An image forming apparatus characterized by:

2. the door unit is configured to support the belt unit outside the apparatus body when in the open position; when the belt unit is located outside the apparatus main body and supported by the door unit in the open position, an upper end of the belt of the belt unit is positioned lower in the vertical direction than an upper end of the door unit; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. the door unit includes a side cover portion that covers at least a portion of a side surface of the device body and an upper cover portion that covers at least a portion of an upper surface of the device body, and is rotatable about a rotation axis that is located below the opening in the vertical direction to move between the closed position and the open position; When the belt unit is located outside the device body, an upper end of the belt is positioned lower in the vertical direction than an upper end of the top cover.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. further comprising a fixing device; When the door unit is in the closed position, the upper cover portion covers the fixing device, and when the door unit is in the open position, the fixing device is exposed.

4. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

5. When the door unit is in the open position, the upper cover portion is always located upstream of the front surface of the belt in the direction in which the belt unit moves from the inside to the outside of the device body.

4. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

6. When the belt unit moves from the inside of the apparatus body to the outside of the apparatus body, the upper end of the belt of the belt unit is always positioned lower in the direction than the upper end of the door unit.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. 7. The image forming apparatus according to claim 1, further comprising a tray unit that is movable between the inside and outside of the device body through the opening when the door unit is in the open position, the tray unit including a cartridge and a tray to which the cartridge is removably attached, one of the cartridge and the tray having the photosensitive drum.

8. When the tray unit moves from inside the device body to outside the device body, the belt unit also moves from inside the device body to outside the device body.

8. The image forming apparatus according to claim 7,

Images