Image forming apparatus

Abstract

An image forming apparatus comprising a cartridge P, a laser scanner 2, a fixing device 80, a shutter 2S, and a door 20. The shutter 2S is movable between a shielding position in which laser light is shielded in a state where the fixing device 80 is detached from an apparatus body 1A, and a transmissive position in which laser light is not shielded in a state where the fixing device 80 is attached to the apparatus body 1A and the door 20 is closed.

Description

Image forming apparatus

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

[0002] In conventional image forming apparatuses, a cartridge system is adopted in which an electrophotographic photoreceptor and process means acting on the electrophotographic photoreceptor are integrally formed into a cartridge, and this cartridge is detachable from the main body of the image forming apparatus. According to the cartridge system, since the maintenance of the apparatus can be performed by the user himself / herself without depending on a service technician, the operability can be improved. Therefore, this cartridge system is widely used in image forming apparatuses. In an image forming apparatus adopting the cartridge system, a mechanism for shielding laser light is incorporated so that laser light is not inadvertently irradiated when replacing the cartridge or performing maintenance on various other components. As these mechanisms, there are those in which the opening and closing of a shutter member are performed in conjunction with the opening and closing of a cover when the cartridge is detached or attached, and those in which the opening and closing of a shutter member are performed in conjunction with the detachment and attachment of the cartridge (see, for example, Japanese Patent Application Laid-Open No. 06-297755 and Japanese Patent Application Laid-Open No. 06-312530).

[0003] In the prior art, when opening and closing the cover to detach and attach the cartridge, the laser shutter opens and closes according to the detachment and attachment operation of the cartridge, so laser light is not irradiated to the outside. In an image forming apparatus, in addition to the detachment and attachment of the cartridge, the cover is opened and closed for the detachment and attachment during maintenance replacement of replacement parts such as a fixing unit and a secondary transfer unit, and the above-described replacement unit shields laser light regardless of the presence or absence of the cartridge. In an image forming apparatus having such a configuration, it is necessary for the laser shutter to open and close according to the detachment and attachment operation of replacement parts other than the cartridge.

[0004] The present invention has been made under such circumstances, and an object thereof is to surely shield laser light even when the cover is opened and closed during the detachment and attachment of a replacement unit other than the cartridge.

[0005] In order to solve the above-described problems, the present invention has the following configuration.

[0006] (1) An image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device detachable from the main body of the apparatus for fixing a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; a shielding member capable of blocking the optical path of the laser light; and an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device, wherein the shielding member is movable between a shielding position that blocks the laser light when the fixing device is detached from the main body of the apparatus, and a transmission position that does not block the laser light when the fixing device is mounted on the main body of the apparatus and the opening / closing member is closed.

[0007] (2) An image forming apparatus comprising: a cartridge having an image carrier and being detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device that is detachable from the main body of the apparatus and fixes a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device; a first detection means for detecting whether the fixing device is attached to the main body of the apparatus; a second detection means for detecting whether the opening / closing member is in an open or closed state; and a control means for enabling the scanner to emit laser light or controlling the scanner so as not to emit laser light based on the detection results of the first and second detection means.

[0008] (3) An image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device detachable from the main body of the apparatus for fixing a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; an interlock that can switch between a power-off state in which no power is supplied to the main body of the apparatus and a power-supply state in which power is supplied to the main body of the apparatus; and an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device, wherein the interlock is in the power-off state when the fixing device is detached from the main body of the apparatus, and is in the power-supply state when the fixing device is attached to the main body of the apparatus and the opening / closing member is closed.

[0009] According to the present invention, laser light can be reliably blocked even when the cover is opened and closed when attaching or detaching replacement units other than the cartridge.

[0010] Figure 1 is a diagram illustrating the overall configuration of the printer in Example 1.

[0011] Figure 2 shows the door in the open state of Example 1 and the movement state of the fixing device.

[0012] Figure 3 shows the extension state of the transfer unit and tray unit in Example 1, and the extension state of the transfer unit alone.

[0013] Figure 4 shows the laser shielding state by the fixing device of Example 1.

[0014] Figure 5 shows the fixing device and the link operation in conjunction with the door in Example 1.

[0015] Figure 6 shows the configuration of the shutter in Example 1.

[0016] Figure 7 is a top view and a cross-sectional view showing the scanner configuration including the shutter of Embodiment 1.

[0017] Figure 8 is a cross-sectional view showing the shielding and transmission states of the shutter of Embodiment 1.

[0018] Figure 9 shows the fixing device and the sensor detection operation linked to the door in Example 2.

[0019] Figure 10 shows the fixing device and the interlock detection operation linked to the door in Example 3.

[0020] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately modified depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of this invention is not intended to be limited to the following embodiments. [Example 1] [Overall Configuration]

[0021] Using Figure 1, the printer 1 as an image forming apparatus will be described. In the following description, the vertical direction will be the Z direction, the direction in which the replacement unit described later is pulled out will be the X direction, and the direction perpendicular to the Z direction and the X direction will be the Y direction. Figure 1 is a diagram illustrating the overall configuration of the printer 1 of Embodiment 1. The printer 1 is an electrophotographic color laser beam printer that forms an image on a sheet S (on the recording material) as a recording material. The printer 1 has a device body (housing) 1A, a scanner (exposure device) 2, a control unit 3, and a door 20 as an opening / closing member that can be opened and closed relative to the device body 1A. The printer 1 has a sheet feeding unit 30, a transfer unit 40, a tray unit (tray unit, moving unit, support unit) 50, and a fixing device 80. The part including the device body 1A and the door 20 can also be called the main frame 100.

[0022] The main frame 100 includes the exterior of the printer 1. The main body 1A houses a laser scanner 2 (scanner), a control unit 3, a sheet feeding unit 30, a transfer unit 40, a tray unit 50, and a fixing device 80. The sheet feeding unit 30 has a loading tray 31 for loading sheets S and a supply roller 32. The loading tray 31 can be pulled out in the direction of the door 20 to replenish the sheets S.

[0023] The tray unit 50 includes 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 removablely mounted on the tray 51. Each of the cartridges PY, PM, PC, and PK can be attached to and detached from 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 color of the toner they contain. Therefore, the configuration and operation of one of the cartridges PY, PM, PC, or PK may be described, and the descriptions of the others may be omitted. Also, when there is no need to distinguish between the cartridges PY, PM, PC, and PK, they may simply be referred to as cartridge P. The tray unit 50 can be said to have a plurality of cartridges P and a tray 51 on which the plurality of cartridges P are removably mounted.

[0024] In Example 1, the tray unit 50 has a plurality of photosensitive drums (image carriers, photoreceptors) 61, a plurality of charging rollers 62 (charging members), and a plurality of developing rollers (developer carriers, developing members) 71. Specifically, the tray unit 50 has four photosensitive drums 61, four charging rollers 62, and four developing rollers 71. The rotation axis direction of the photosensitive drum 61, the rotation axis direction of the developing roller 71, and the rotation axis direction of the charging roller 62 are parallel. The part that forms the black (K) image is called the black station (first station), and 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. The part that forms the cyan (C) image is called the cyan station (second station), and the photosensitive drum 61 of the second station is called the second photosensitive drum, the developing roller 71 is called the second developing roller, and the charging roller 62 is called the second charging roller. The part that forms the magenta (M) image is called the magenta station (third station), and 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. The part that forms the yellow (Y) image is called the yellow station (fourth station), and 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.

[0025] Cartridge PK is installed in the black station, cartridge PC in the cyan station, cartridge PM in the magenta station, and cartridge PY in the yellow station. In Example 1, cartridge PK is referred to as the first cartridge, cartridge PC as the second cartridge, cartridge PM as the third cartridge, and cartridge PY as the fourth cartridge. The numbers 1st, 2nd, 3rd, and 4th are used for convenience in explanation. The photosensitive drum 61, charging roller 62, and developing roller 71 may be provided in either cartridge P or tray 51. In Example 1, cartridge P has the photosensitive drum 61, charging roller 62, and developing roller 71.

[0026] The transfer unit 40 includes a belt 41, a primary transfer roller 42, a cleaning unit 43, a drive roller 46 for driving the belt 41, and a tension roller (driven roller) 47. The printer 1 is equipped with an optical sensor 44 for detecting the toner image (developer image) transferred to the belt 41. The belt 41 is positioned below the photosensitive drum 61 and is able to contact the photosensitive drum 61 so that a primary transfer section is formed between the belt 41 and the photosensitive drum 61. The printer 1 also has a secondary transfer roller 45 (transfer member) that contacts the belt 41 so that a secondary transfer section is formed. The secondary transfer section is formed between the belt 41 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. A pair of registration rollers 4 is positioned in front of the secondary transfer section. [Fusing device]

[0027] The fixing device 80 includes a fixing unit 81 and a flapper 5. When an image forming operation is performed on the sheet S, the fixing device 80 is in the use position. When the shutter 2S, described later, is in a transparent state, the fixing device 80 in the use position shields the laser beam from the door 20 at the upstream end with respect to the projection direction of the laser beam and the door 20. The fixing device 80 is housed inside the main body 1A when in the use position. The fixing device 80 is also configured to heat the sheet S when in the use position. In Embodiment 1, the fixing unit 81 includes a heating unit (heating roller) including a heater and a pressurizing unit (pressurizing roller).

[0028] The movement of the transfer unit 40 and the tray unit 50 will be explained using Figures 1, 2, and 3. Note that some reference numerals have been omitted in Figures 1 to 3. Figure 2(a) shows the printer 1 with the door 20 open. Figure 2(b) shows the printer 1 with the fuser 80 moved. Figure 3(a) shows the printer 1 with the transfer unit 40 and the tray unit 50 extended. Figure 3(b) shows the printer 1 with the transfer unit 40 extended independently.

[0029] The transfer unit 40 and the tray unit 50 are movable from the inside to the outside of the device body 1A. In the horizontal direction X, the device body 1A has a first end 1b1 with an opening 1A1 and a second end 1b2 opposite to the first end 1b1. The tray unit 50 is movable through the opening 1A1 to a first inner position inside the device body 1A and to a first outer position outside the device body 1A. The transfer unit 40 is movable through the opening 1A1 to a second inner position inside the device body 1A and to a second outer position outside the device body 1A. The opening 1A1 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 moves, and at least a portion of the belt 41 protrudes from the device body 1A toward the outside.

[0030] The direction in which the tray unit 50 moves from the first inner position to the first outer position is called the tray removal direction Dd1, and the direction opposite to the tray removal direction Dd1 is called the tray mounting direction Da1. The tray removal direction Dd1 can be described as the direction from the second end 1b2 to the first end 1b1. The direction in which the transfer unit 40 moves from the second inner position to the second outer position is called the transfer removal direction Dd2, and the direction opposite to the transfer removal direction Dd2 is called the transfer mounting direction Da2. In the transfer removal direction Dd2, the drive roller 46 is located downstream of the tension roller 47. The transfer removal direction Dd2 can be described as the direction from the second end 1b2 to the first end 1b1.

[0031] The tray removal direction Dd1 and the tray mounting direction Da1 are directions that intersect (preferably orthogonal to) the rotation axis direction of the photosensitive drum 61. The transfer removal direction Dd2 and the transfer mounting direction Da2 are directions that intersect (preferably orthogonal to) the rotation axis direction of the drive roller 46. The rotation axis direction of the drive roller 46 is parallel to the rotation axis direction of the photosensitive drum 61. In the horizontal direction X, the fixing device 80 is located on one end side of the apparatus body 1A (the side where the first end 1b1 is located).

[0032] The door 20 attached to the main body 1A of the device is movable between a closed position and an open position.

[0033] As shown in Figure 1, when the door 20 is in the closed position (closed state), the door 20 covers the opening 1A1. As shown in Figure 2(a), when the door 20 is in the open position (open state), the opening 1A1 is exposed. As shown in Figure 1, when the door 20 is in the closed position, the door 20 covers the fixing device 80 attached to the main body 1A. More specifically, when the door 20 is in the closed position, the upper cover portion 20b of the door 20 is located above the fixing device 80. The upper cover portion 20b of the door 20 functions as part of the exterior. The door 20 can move between the open and closed positions while the fixing device 80 is supported by the main body 1A. In other words, the door 20 moves from the closed position to the open position so as to move away from the fixing device 80 supported by the main body 1A. Therefore, as shown in Figure 2(a), when the door 20 is in the open position, the door 20 is separated from the fixing device 80 supported by the main body 1A of the device.

[0034] The fixing device 80 is movable from the state shown in Figure 2(a) to the state shown in Figure 2(b) so that the opening 1A1 is widely exposed. More specifically, the fixing device 80 can be retracted in the +Z direction (upward) so that the opening 1A1 is widely exposed. With the door 20 and the fixing device 80 moved (Figure 2(b)), the transfer unit 40 and the tray unit 50 can move from the inside to the outside of the device body 1A through the opening 1A1, and after the movement, it will be in the state shown in Figure 3(a). In this way, because the fixing device 80 can be retracted upward, the transfer unit 40 and the tray unit 50 can be housed in the device body 1A diagonally rather than horizontally, as shown in Figure 1, etc. Reference numeral 85 denotes an arm for moving the fixing device 80 upward, and reference numeral 85A denotes the pivot axis of the arm 85.

[0035] With the tray unit 50 moved to the outside of the main body 1A (Figure 3(a)), it is permissible to remove cartridges PY, PM, PC, and PK from the tray 51 and to attach cartridges PY, PM, PC, and PK to the tray 51. This allows cartridges PY, PM, PC, and PK to be replaced with new cartridges PY, PM, PC, and PK. In Embodiment 1, cartridge P is detachable from the tray 51 in a direction intersecting (preferably perpendicular to) the rotation axis of the photosensitive drum 61.

[0036] Cartridges PY, PM, PC, and PK are removed from the tray 51 by moving them away from the transfer unit 40 relative to the tray 51. In other words, cartridges PY, PM, PC, and PK are removed from the tray 51 by moving them away from the transfer unit 40 relative to the tray 51. In Embodiment 1, the transfer unit 40 is located below the tray unit 50. Therefore, cartridges PY, PM, PC, and PK are removed from the tray 51 by moving them upward relative to the tray 51. Furthermore, the transfer unit 40 is detachable from the main body 1A independently of the tray unit 50 and can be replaced with a new transfer unit 40. [Image forming operation]

[0037] The image formation operation of printer 1 will be explained using Figure 1. The control unit 3 of printer 1 starts the image formation operation on the sheet S based on the image signal received from the external host device 400. The external host device 400 is, for example, a personal computer, an image reader, and a facsimile machine.

[0038] When an image is formed on the sheet S, the fixing device 80 is in the use position, the tray unit 50 is in the first inner position, the transfer unit 40 is in the second inner position, and the door 20 is in the closed position. With the transfer unit 40 in the second inner position, the belt 41 can contact the photosensitive drum 61. At this time, the tray unit 50 is positioned above the transfer unit 40.

[0039] When an image is formed on the sheet S, a charging voltage is applied to the charging roller 62, causing the photosensitive drum 61 to rotate. A laser corresponding to the image information is emitted from the laser scanner 2 to the photosensitive drum 61, and the surface of the photosensitive drum 61, which has been charged by the charging roller 62, is exposed. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 61.

[0040] 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 by the toner supplied from the developing roller 71, forming a toner image on the surface of the photosensitive drum 61. In Example 1, the developing roller 71 develops the electrostatic latent image while in contact with the photosensitive drum 61, but the developing roller 71 may develop the electrostatic latent image with a gap between the developing roller 71 and the photosensitive drum 61.

[0041] When a full-color image is formed, toner images of each color are formed on each photosensitive drum 61. In Embodiment 1, with the tray unit 50 in the first inner position, the developing roller 71 is movable between a contact position in contact with the photosensitive drum 61 and a separated position away from the photosensitive drum 61. Specifically, a switching device provided in the main body 1A switches between the developing roller 71 being in the contact position and the developing roller 71 being in the separated position. This allows the developing roller 71 to be kept away from the photosensitive drum 61 when no image forming operation is being performed.

[0042] Furthermore, printer 1 can perform monochrome printing with the developing roller 71 corresponding to cartridge PK and the photosensitive drum 61 in contact, and with the developing roller 71 corresponding to cartridges PY, PM, and PC separated. Also, printer 1 can perform full-color printing with the photosensitive drum 61 corresponding to cartridges PY, PM, PC, and PK in contact with the belt 41. The toner image formed on each photosensitive drum 61 is transferred onto the belt 41 by the primary transfer roller 42 in the primary transfer section and transported toward the secondary transfer section formed by the belt 41 and the secondary transfer roller 45.

[0043] On the other hand, a conveyance path (first path, first conveyance path) 1c through which the sheet S heading toward the fixing device 80 passes is formed in the apparatus main body 1A. Further, a duplex conveyance path (second path, second conveyance path) 20a through which the sheet S that has passed through the fixing device 80 passes is formed in the door 20. The door 20 covers the conveyance path 1c in the closed state. When the door 20 is opened, the conveyance path 1c and the duplex conveyance path 20a are exposed (see Fig. 2(a)).

[0044] In the sheet feeding unit 30, out of the plurality of sheets S stacked on the stacking tray 31, one sheet S is separated and fed by the supply roller 32 at a predetermined timing, and is conveyed through the conveyance path 1c toward the secondary transfer unit and the fixing device 80. In the secondary transfer unit, 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 from the belt 41 by a cleaning blade (cleaning member) 43A provided in the cleaning unit 43.

[0045] The sheet S on which the toner image has been transferred in the secondary transfer unit is conveyed toward the fixing device 80. In the fixing device 80, the sheet S is heated and pressed by the fixing unit 81, and the unfixed toner image is fixed to the sheet S. The sheet S on which the toner image has been fixed is conveyed toward the flapper 5 as a path switching unit. The flapper 5 is movable to a discharge position for guiding the sheet S that has passed through the fixing device 80 toward the discharge path 1d and a reverse position for guiding the sheet S toward the reverse path 1e. When single-sided printing in which an image is formed on one side of the sheet S is performed, the sheet S is guided to the discharge path 1d by the flapper 5 and discharged to the discharge tray 1f formed at the upper part of the apparatus main body 1A.

[0046] On the other hand, in the case of double-sided printing where images are printed on both the front and back sides of the sheet S, the sheet S is guided to the reverse path 1e by the flapper 5. After the sheet S is guided to the reverse path 1e, the conveyance direction of the sheet S is reversed, and the sheet S is conveyed toward the secondary transfer unit through the double-sided conveyance path 20a formed in the door 20. In the secondary transfer unit, after the toner image is transferred to the back side of the sheet S, the sheet S passes through the fixing device 80, is guided to the discharge path 1d by the flapper 5, and is discharged to the discharge tray 1f of the apparatus main body 1A. [Operation of shutter according to door opening / closing operation and attachment / detachment state of fixing device]

[0047] As described above, the photosensitive drum 61 charged by the charging roller 62 is irradiated with lasers 2Y, 2M, 2C, 2K (see FIG. 4) from the laser scanner 2 to form an electrostatic latent image. These lasers 2Y, 2M, 2C, 2K must be reliably shielded by the exterior including the door 20 from the viewpoint of user safety. Therefore, it is necessary to control the laser irradiation state from the laser scanner 2 according to the operation of the openable and closable door 20. In addition, it is necessary to shield the lasers 2Y, 2M, 2C, 2K according to the attachment state of the apparatus main body 1A of the tray unit 50, the transfer unit 40, and the fixing device 80 including the cartridges PY, PM, PC, PK that can be exchanged by the user described above.

[0048] FIG. 4 shows the attachment state of the fixing device 80 to the apparatus main body 1A in a state where the tray unit 50 and the transfer unit 40 including the cartridges PY, PM, PC, PK are not attached to the apparatus main body 1A. FIG. 4(a) shows that the fixing device 80 is attached to the apparatus main body 1A, and the lasers 2Y, 2M, 2C, 2K can be shielded regardless of the opening / closing of the door 20. Here, Ls is a virtual line indicating the line of sight of the user, and will be referred to as the virtual line Ls hereinafter. In FIG. 4(a), even if the door 20 is assumed to be in an open state, since the virtual line Ls intersects the fixing device 80, the lasers 2Y, 2M, 2C, 2K, particularly the laser 2Y closest to the front as viewed from the door 20 side, are shielded by the fixing device 80.

[0049] On the other hand, in Figure 4(b), the fixing device 80 is not mounted on the main body 1A, and when the door 20 is opened, the lasers 2Y, 2M, 2C, and 2K are not shielded. In other words, if the door 20 were open in Figure 4(b), the lasers 2Y, 2M, 2C, and 2K, especially the laser 2Y closest to the door 20, would not be shielded by the fixing device 80. Therefore, it is necessary to control the laser shielding state according to the state in which the fixing device 80 is mounted on the main body 1A.

[0050] To achieve this requirement, a shutter 2S that shields the laser, a fixing link 80L that is linked to the attachment and detachment of the fixing device 80, and a shutter link 90 are required, as shown in Figure 5. The shutter 2S is a shielding member that can block the optical path of the laser light emitted from the laser scanner 2. Figure 5(a) shows the fixing device 80 mounted on the device body 1A and the door 20 closed. In this state, the fixing link 80L inside the fixing device 80 moves due to the pressing member 20P (pressing part) located on the door 20. More specifically, the fixing link 80L moves when one end 80La (pressed part) of the fixing link 80L is pressed by the pressing member 20P.

[0051] The shutter link 90 moves in the same way as the fixed link 80L moves. More specifically, the shutter link 90 moves when one end 90a of the shutter link 90 is pressed against the other end 80Lb of the fixed link 80L. At this time, as the shutter link 90 moves, the shutter 2S rotates in a counterclockwise direction (hereinafter referred to as the CCW direction) when viewed from the side of the regulating wall 2S4, which will be described later, so that the lasers 2Y, 2M, 2C, and 2K can be irradiated. That is, the shutter 2S moves to the transmission position when the pressing member 20P is pressing against the end 80La of the fixed link 80L.

[0052] Figure 5(b) shows the state in which the fixing device 80 is attached to the main body 1A and the door 20 has begun to open. As the door 20 moves from the state in Figure 5(b) to the open state in Figure 2(a), the pressing member 20P moves away from the end 80La of the fixing link 80L. The fixing link 80L is biased by an elastic member (not shown) to follow the movement of the pressing member 20P. The shutter link 90 is also biased by an elastic member (not shown) to follow the movement of the fixing link 80L. As the door 20 opens in this way, the shutter link 90 moves away, and the shutter 2S rotates clockwise (hereinafter referred to as the CW direction) when viewed from the side of the regulating wall 2S4, thereby shielding the lasers 2Y, 2M, 2C, and 2K. In other words, the shutter 2S moves to the shielding position when the pressing member 20P moves away from the end 80La.

[0053] As shown in Figure 5(c), when the fixing device 80 is detached from the main body 1A, the fixing link 80L does not exist. Therefore, the shutter link 90 moves apart, and the shutter 2S rotates in the CW direction, so that the lasers 2Y, 2M, 2C, and 2K are always shielded by the shutter 2S regardless of the open or closed state of the door 20. [Control configuration for laser shielding and irradiation by shutter operation]

[0054] Next, the laser shielding configuration associated with the shutter operation described above will be explained in detail. Figure 6 shows a schematic perspective view of the shutter 2S of Embodiment 1. The shutter 2S is movable between a shielding position that shields the laser light when the fixing device 80 is detached from the main body 1A, and a transmission position that does not shield the laser light when the fixing device 80 is attached to the main body 1A and the door 20 is closed.

[0055] As shown in Figure 6, the shutter 2S consists of a rotating shaft 2S1, a laser light shielding wall 2S2, a rotating boss 2S3, a regulating wall 2S4, and a positioning projection 2S5 (first engaging part). Figure 7(a) shows a bottom view of the shutter 2S installed on the laser scanner 2 (view of the laser scanner 2 from the bottom side of the device body 1A), and Figure 7(b) shows a cross-sectional view. First, the center CL of the rotating shaft 2S1 of the shutter 2S is located below the rotating polyhedron mirror 210 of the laser scanner 2, and is positioned on the bisector E of the lasers 2K, 2C and 2M, 2Y incident from a semiconductor laser (not shown) onto the rotating polyhedron mirror 210. The direction of the rotating shaft 2S1 is the Y direction, and the direction of the rotation axis of the rotating polyhedron mirror 210 is the Z direction.

[0056] Next, the positional restriction of the shutter 2S relative to the laser scanner 2 will be explained. As shown in Figure 7(a), the X direction is restricted by the rotation axis 2S1 provided on the laser scanner 2, by the first restricting wall 201 and the second restricting wall 202. The Y direction is restricted by the shielding wall 2S2 and the restricting wall 2S4 sandwiching the first restricting wall 201 and the second restricting wall 202. As shown in Figure 7(b), the Z direction is restricted by the rotation axis 2S1 provided on the laser scanner 2, by the third restricting wall 203 and the fourth restricting wall 204, and by the fifth restricting wall 205 and the sixth restricting wall 206, which are positioned opposite the third restricting wall 203 and the fourth restricting wall 204, respectively.

[0057] More specifically, on the side of the rotating shaft 2S1 where the shielding wall 2S2 is provided, movement in the Z direction is restricted by the third restricting wall 203 and the fifth restricting wall 205, which is provided opposite the third restricting wall 203. On the side of the rotating shaft 2S1 where the restricting wall 2S4 is provided, movement in the Z direction is restricted by the fourth restricting wall 204 and the sixth restricting wall 206, which is provided opposite the fourth restricting wall 204. In addition, each restricting part is provided with clearance to allow the shutter 2S to operate smoothly.

[0058] Next, the operation of the shutter 2S in Example 1 will be explained with reference to Figure 8. Figure 8(a) shows the positional relationship between the shutter 2S, lasers 2K, 2C, 2M, 2Y, and the rotating polyhedron mirror 210 when the door 20 is open or the fixing device 80 has been removed. Figure 8(b) shows the positional relationship between the shutter 2S, lasers 2K, 2C, 2M, 2Y, and the rotating polyhedron mirror 210 when the fixing device 80 is installed and the door 20 is closed.

[0059] As shown in Figure 8(a), when the door 20 is open or the fixing device 80 is removed, the lasers 2K, 2C, 2M, and 2Y are prevented from leaking outside the laser scanner 2. That is, the optical paths of the lasers 2K, 2C, 2M, and 2Y from the semiconductor laser (not shown) to the rotating polyhedron mirror 210 are blocked by the shielding wall 2S2. At this time, as viewed from the side of the restricting wall 2S4, the shutter 2S rotates in the CW direction, and the positioning projection 2S5 engages (contacts) with the engaging portion 90e of the shutter link 90 to maintain its position. As shown in Figure 8(b), when the door 20 is closed and the fixing device 80 is installed, as viewed from the side of the restricting wall 2S4, the shutter 2S rotates in the CCW direction. As a result, the optical paths of the lasers 2K, 2C, 2M, and 2Y from the semiconductor laser (not shown) to the rotating polyhedron mirror 210 are opened, and the electrostatic latent image described above can be formed.

[0060] In Example 1, the fixing link 80L and the shutter link 90 are configured to operate linearly, but the method of operation is not limited to linear motion. Also, the shutter 2S rotates to irradiate / shield the laser, but the operation of the shutter 2S is not limited to rotation; it may also irradiate / shield the laser linearly. In this way, the fixing link 80L, shutter link 90, and shutter 2S, which are linked to the attachment and detachment of the fixing device 80, ensure that the lasers 2Y, 2M, 2C, and 2K are reliably shielded regardless of the state in which the user opens the door 20.

[0061] As described above, according to Example 1, the laser light can be reliably blocked even when the cover is opened and closed when attaching or detaching replacement units other than the cartridge. [Example 2] <Electric shutter>

[0062] Example 2 is a configuration in which the shielding state of lasers 2Y, 2M, 2C, and 2K is controlled by means of detecting the state in which the fixing device 80 is attached to the device body 1A, without using the fixing link 80L and shutter link 90 described in Example 1 above.

[0063] As shown in Figure 9, the printer 1 is equipped with a fuser switch 80S that detects whether the fuser unit 80 is mounted on the main unit 1A, and a door switch 20S (second detection means) that detects whether the door 20 is open or closed. The door 20 has a pressing portion 20c that presses against the door switch 20S. The fuser unit 80 has a pressing portion 80a that presses against the fuser switch 80S. The pressing portion 80a may be the bottom of the fuser unit 80. The fuser switch 80S functions as a first detection means (detection means) that detects whether or not the fuser unit 80 is mounted on the main unit 1A. The control unit 3 functions as a control means that controls the laser scanner 2 based on the detection result from the fuser switch 80S.

[0064] The control unit 3 receives detection signals from the fixing switch 80S and the door switch 20S. The control unit 3 determines that the fixing device 80 is installed when the pressing part 80a is pressing the fixing switch 80S, and determines that the fixing device 80 is removed when the pressing part 80a is not pressing the fixing switch 80S. The control unit 3 also determines that the door 20 is closed when the pressing part 20c is pressing the door switch 20S, and determines that the door 20 is open when the pressing part 20c is not pressing the door switch 20S.

[0065] If the control unit 3 detects, based on the detection result of the fixing switch 80S, that the fixing device 80 has been removed from the main body 1A, it controls the laser scanner 2 so as not to irradiate (emit) the lasers 2Y, 2M, 2C, and 2K. On the other hand, if the control unit 3 detects, based on the detection result of the fixing switch 80S, that the fixing device 80 has been attached to the main body 1A, it further detects, based on the detection result of the door switch 20S, that the door 20 has been closed, and then irradiates the lasers 2Y, 2M, 2C, and 2K.

[0066] In Figure 9(a), the door 20 is closed and the fixing device 80 is installed, so the control unit 3 is in a state where it can emit a laser from the laser scanner 2 (ready to emit). On the other hand, in Figure 9(b), the fixing device 80 is installed but the door 20 is open, so the control unit 3 does not emit a laser from the laser scanner 2. In Figure 9(c), the door 20 is closed but the fixing device 80 is not installed, so the control unit 3 does not emit a laser from the laser scanner 2.

[0067] In this way, the control unit 3 controls the irradiation / shielding of lasers 2Y, 2M, 2C, and 2K based on the detection signals of the fixing switch 80S and the door switch 20S. As a result, lasers 2Y, 2M, 2C, and 2K can be reliably shielded regardless of the conditions under which the user opens the door 20.

[0068] Alternatively, the printer 1 may be equipped with the shutter 2S of Embodiment 1, and the control unit 3 may control the shutter 2S based on the detection results of the fuser switch 80S and the door switch 20S. That is, the control unit 3 may control the shutter 2S to move to the transparent position when the fuser device 80 is installed and the door 20 is closed, based on the detection results of the fuser switch 80S and the door switch 20S. Alternatively, the control unit 3 may control the shutter 2S to move to the shielding position when the fuser device 80 is removed or the door 20 is open, based on the detection results of the fuser switch 80S and the door switch 20S.

[0069] As described above, according to Example 2, the laser light can be reliably blocked even when the cover is opened and closed when attaching or detaching replacement units other than the cartridge. [Example 3] <Interlock shutter>

[0070] In Example 3, the interlock switch 101 is controlled by the other end 90b of the shutter link 90 pressing against the arm 101a of the interlock switch 101, as described in Example 1 above. This interlock switch 101 is an electrical component that controls the supply of power to the main body 1A of the device. The interlock switch 101 can switch between a power-off state, in which no power is supplied to the printer 1, and a power-supply state, in which power is supplied to the printer 1. The interlock switch 101 is in a power-off state when the fuser 80 is detached from the main body 1A of the device, and in a power-supply state when the fuser 80 is attached to the main body 1A of the device and the door 20 is closed.

[0071] As shown in Figure 10, the fixing link 80L and the shutter link 90 operate in the same manner as in Embodiment 1, so that the fixing device 80 is mounted on the device body 1A and the door 20 is closed, at which point the interlock switch 101 is driven. Similar to Embodiment 1, the fixing device 80 has an end portion 80La (pressed portion) of the fixing link 80L that is pressed by the pressing member 20P (pressing portion) of the door 20. The interlock switch 101 is powered when the pressing member 20P is pressing the end portion 80La (Figure 10(a)). Power is supplied to the device body 1A, so that lasers 2Y, 2M, 2C, and 2K are irradiated.

[0072] On the other hand, when the door 20 is open, or when the fixing device 80 is detached from the main body 1A, the interlock switch 101 is not driven (Figures 10(b) and 10(c)). The interlock switch 101 enters a power-off state when the pressing member 20P moves away from the end 80La. Since power is not supplied to the main body 1A, the lasers 2Y, 2M, 2C, and 2K are not emitted, which is equivalent to the lasers 2Y, 2M, 2C, and 2K being shielded.

[0073] In this way, the drive of the interlock switch 101 is controlled by the fixing link 80L and the shutter link 90, which are linked to the attachment and detachment of the fixing device 80. As a result, the lasers 2Y, 2M, 2C, and 2K can be reliably shielded regardless of the state in which the user opens the door 20.

[0074] As described above, according to Example 3, the laser light can be reliably blocked even when the cover is opened and closed when attaching or detaching replacement units other than the cartridge.

[0075] The disclosure of this embodiment includes the following configuration: (Configuration 1)

[0076] Image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device detachable from the main body of the apparatus for fixing a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; a shielding member capable of blocking the optical path of the laser light; and an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device, wherein the shielding member is movable between a shielding position that blocks the laser light when the fixing device is detached from the main body of the apparatus, and a transmission position that does not block the laser light when the fixing device is mounted on the main body of the apparatus and the opening / closing member is closed. (Configuration 2)

[0077] The fixing device, when the shielding member is in the transmission position, shields the laser beam from the opening / closing member at the upstream end with respect to the projection direction of the laser beam and the opening / closing member, as described in Configuration 1. (Configuration 3)

[0078] The image forming apparatus according to Configuration 1, wherein the opening / closing member has a pressing portion, the fixing device has a pressed portion that is pressed by the pressing portion, and the shielding member is in the transparent position when the pressing portion is pressing the pressed portion, and moves to the shielding position when the pressing portion moves away from the pressed portion. (Configuration 4)

[0079] The image forming apparatus according to configuration 1, comprising: detection means for detecting whether the fixing device is attached to the main body of the apparatus; and control means for controlling the shielding member to switch the shielding member to the shielding position or the transparent position based on the detection result by the detection means. (Configuration 5)

[0080] An image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device that is detachable from the main body of the apparatus and fixes a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device; a first detection means for detecting whether the fixing device is attached to the main body of the apparatus; a second detection means for detecting whether the opening / closing member is in an open or closed state; and a control means for controlling the scanner to enable or prevent the scanner from emitting laser light based on the detection results of the first and second detection means. (Configuration 6)

[0081] The image forming apparatus according to configuration 5, wherein the control means enables the emission of laser light from the scanner when the first detection means detects that the fixing device is mounted on the main body of the apparatus and the second detection means detects that the opening / closing member is in the closed state, and controls the scanner so as not to emit laser light when the first detection means detects that the fixing device has been removed or the second detection means detects that the opening / closing member is in the open state. (Configuration 7)

[0082] Image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device detachable from the main body of the apparatus for fixing a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; an interlock switch capable of switching between a power-off state in which no power is supplied to the main body of the apparatus and a power-supply state in which power is supplied to the main body of the apparatus; and an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device, wherein the interlock switch is in the power-off state when the fixing device is detached from the main body of the apparatus, and is in the power-supply state when the fixing device is attached to the main body of the apparatus and the opening / closing member is closed. (Configuration 8)

[0083] The image forming apparatus according to configuration 5, wherein the scanner does not emit laser light when the interlock switch is powered off, and emits laser light when the interlock is powered. (Configuration 9)

[0084] The fixing device, when the scanner is emitting laser light, shields the laser light from the opening / closing member at the upstream end with respect to the projection direction of the laser light and the opening / closing member, as described in configuration 5 of the image forming apparatus. (Configuration 10)

[0085] The image forming apparatus according to configuration 5, wherein the opening / closing member has a pressing portion, the fixing device has a pressed portion that is pressed by the pressing portion, and the interlock switch is in the power supply state when the pressing portion is pressing the pressed portion, and is in the power stop state when the pressing portion moves away from the pressed portion.

[0086] According to the present invention, an image forming apparatus is provided that can reliably block laser light even when the cover is opened and closed.

[0087] The present invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are attached to make the scope of the invention public.

[0088] This application claims priority based on Japanese Patent Application No. 2024-158652, filed on September 12, 2024, and all of its contents are incorporated herein by reference.

Claims

1. An image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device detachable from the main body of the apparatus for fixing a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; a shielding member capable of blocking the optical path of the laser light; and an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device, wherein the shielding member is movable between a shielding position that blocks the laser light when the fixing device is detached from the main body of the apparatus, and a transmission position that does not block the laser light when the fixing device is mounted on the main body of the apparatus and the opening / closing member is closed.

2. The fixing device, when the shielding member is in the transmission position, shields the laser light from the opening / closing member at the upstream end with respect to the projection direction of the laser light and the opening / closing member, as described in claim 1.

3. The image forming apparatus according to claim 1, wherein the opening / closing member has a pressing portion, the fixing device has a pressed portion that is pressed by the pressing portion, and the shielding member is in the transparent position when the pressing portion is pressing the pressed portion, and moves to the shielding position when the pressing portion moves away from the pressed portion.

4. An image forming apparatus according to claim 1, comprising: detection means for detecting whether or not the fixing device is attached to the main body of the apparatus; and control means for controlling the shielding member to switch the shielding member to the shielding position or the transparent position based on the detection result by the detection means.

5. An image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device that is detachable from the main body of the apparatus and fixes a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device; a first detection means for detecting whether or not the fixing device is attached to the main body of the apparatus; a second detection means for detecting whether the opening / closing member is in an open or closed state; and a control means for enabling the scanner to emit laser light or controlling the scanner so as not to emit laser light based on the detection results of the first and second detection means.

6. The image forming apparatus according to claim 5, wherein the control means enables the emission of laser light from the scanner when the first detection means detects that the fixing device is mounted on the apparatus body and the second detection means detects that the opening / closing member is in the closed state, and controls the scanner so as not to emit laser light when the first detection means detects that the fixing device has been removed or the second detection means detects that the opening / closing member is in the open state.

7. An image forming apparatus comprising: a cartridge having an image carrier and detachable from the main body of the apparatus; a scanner that emits laser light to form a latent image on the image carrier; a fixing device detachable from the main body of the apparatus for fixing a toner image onto a sheet onto which a toner image developed from the latent image formed on the image carrier has been transferred; an interlock switch capable of switching between a power-off state in which no power is supplied to the main body of the apparatus and a power-supply state in which power is supplied to the main body of the apparatus; and an opening / closing member that can be opened and closed relative to the main body of the apparatus for attaching and detaching the cartridge and the fixing device, wherein the interlock switch is in the power-off state when the fixing device is detached from the main body of the apparatus, and is in the power-supply state when the fixing device is attached to the main body of the apparatus and the opening / closing member is closed.

8. The image forming apparatus according to claim 7, wherein the scanner does not emit laser light when the interlock switch is powered off, and emits laser light when the interlock is powered.

9. The image forming apparatus according to claim 7, wherein the fixing device shields the laser light from the opening / closing member at the upstream position with respect to the projection direction of the laser light and the opening / closing member when the scanner is emitting laser light.

10. The image forming apparatus according to claim 7, wherein the opening / closing member has a pressing portion, the fixing device has a pressed portion that is pressed by the pressing portion, and the interlock switch is in the power supply state when the pressing portion is pressing the pressed portion, and is in the power stop state when the pressing portion moves away from the pressed portion.

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