Drum unit

Abstract

The present invention provides a structure that allows the holder to be moved without getting caught in an opening provided in the frame. [Solution] The drum unit 2 comprises a charging wire 41, a charging frame 33, a cleaner, and a holder 60. The charging wire 41 charges the outer surface of the photoreceptor drum. The charging frame 33 supports the charging wire 41. The cleaner cleans the charging wire 41. The holder 60 holds the cleaner. The holder 60 moves along the charging wire 41 in a first direction together with the cleaner. The charging frame 33 has a first guide rail 71, an opening 73, and a second guide rail 74. The first guide rail 71 guides the holder 60 in a first direction. The opening 73 is located between the first guide rail 71 and one end of the charging frame 33 in a first direction. The second guide rail 74 is located on one side of the opening 73 in a second direction intersecting the first direction and guides the holder 60 in a first direction.

Description

Technical Field

[0001] The present disclosure relates to a drum unit.

Background Art

[0002] Conventionally, electrophotographic image forming apparatuses such as laser printers and LED printers are known. For conventional image forming apparatuses, for example, they are described in Patent Document 1. The image forming apparatus of Patent Document 1 includes a developing cartridge having a developing roller and a drum unit having a photosensitive drum. The developing cartridge is attached to the drum unit. Further, the drum unit to which the developing cartridge is attached is attached to the image forming apparatus.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The drum unit has a charging wire for charging the outer peripheral surface of the photosensitive drum. Further, the drum unit has a cleaner for cleaning the charging wire and a holder for moving the cleaner along the charging wire. The holder moves along a guide rail provided on the frame of the drum unit. After cleaning, the holder is returned along the guide rail to a position where it contacts a wall provided at one end of the drum unit.

[0005] However, drum units may have an opening between the guide rail and the wall. This opening may be provided, for example, during the manufacturing of the drum unit to allow a holder to pass through. In this case, when the holder is moved towards the wall after cleaning, it may get caught in the opening. Printing may then begin with the holder still caught in the opening.

[0006] Therefore, the object of this disclosure is to provide a structure that allows the holder to be moved without getting caught in an opening provided in the frame. [Means for solving the problem]

[0007] The first disclosure is a drum unit comprising: a photoreceptor drum rotatable about a drum axis extending in a first direction; a charging wire extending in the first direction along the outer surface of the photoreceptor drum, the charging wire charging the outer surface of the photoreceptor drum; and a charging frame supporting the charging wire, wherein the drum unit comprises: a cleaner for cleaning the charging wire; and a holder for holding the cleaner, the holder moving in the first direction along the charging wire together with the cleaner with respect to the charging frame between one end and the other end of the charging frame in the first direction, the charging frame comprising: a first guide rail having a first guide surface for guiding the holder in the first direction; an opening located between the first guide rail and one end of the charging frame in the first direction; and a second guide rail located on one side of the opening in a second direction intersecting the first direction, and having a second guide surface for guiding the holder in the first direction.

[0008] The second disclosure is a drum unit of the first disclosure, wherein the charging frame is located between the second guide rail and the other end of the charging frame in the first direction and has a non-contact surface that is spaced apart from the holder in a third direction intersecting the first and second directions, and the second guide rail has an inclined surface that connects the non-contact surface and the second guide surface and whose position in the third direction gradually changes according to the position in the first direction, and which guides the holder in the first direction.

[0009] The third disclosure is a drum unit of the first or second disclosure, characterized in that the second guide rail is located only on one of the two sides of the opening in the second direction.

[0010] The fourth disclosure is a drum unit according to any one of the first to third disclosures, wherein the charging frame further has a wall located at one end in the first direction, and when the holder is located at one end of the charging frame in the first direction, the holder is in contact with the wall.

[0011] The fifth disclosure is a drum unit according to any one of the first to fourth disclosures, characterized in that the position of the second guide surface in a third direction intersecting the first and second directions is the same as the position of the first guide surface in the third direction, or is further away from the charged wire than the position of the first guide surface in the third direction.

[0012] The sixth disclosure is a drum unit of the second disclosure, characterized in that one end of the first guide rail and the inclined surface are located at the same position in the first direction.

[0013] The seventh disclosure is a drum unit according to any one of the first to sixth disclosures, wherein the charging frame further comprises a third guide rail located between the opening and one end of the charging frame in a first direction, the third guide rail having a tapered surface that approaches the charging wire in a third direction intersecting the first and second directions as it approaches the opening in the first direction.

[0014] The eighth disclosure is a drum unit according to any one of the first to seventh disclosures, comprising: a first photoreceptor drum which is the photoreceptor drum; a second photoreceptor drum separate from the first photoreceptor drum; a first charging wire which is the charging wire which charges the outer surface of the first photoreceptor drum; and a second charging wire separate from the first charging wire which charges the outer surface of the second photoreceptor drum. [Effects of the Invention]

[0015] According to the first to eighth disclosures, the holder can be moved in the first direction between the first guide rail and one end of the charging frame in the first direction without getting caught in the opening.

[0016] Furthermore, according to the second disclosure, the holder can be smoothly moved between a position facing the non-contact surface and a position in contact with the second guide surface.

[0017] Furthermore, according to the sixth disclosure, the holder can be continuously guided by the first guide rail and the second guide rail.

[0018] Furthermore, according to the seventh disclosure, the holder can be smoothly moved from the second guide rail to the third guide rail. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram of an image forming apparatus. [Figure 2]It is a perspective view of a drum unit. [Figure 3] It is a cross-sectional view of the drum unit in the vicinity of the photoreceptor drum and the charger. [Figure 4] It is a partial perspective view of the charging frame. [Figure 5] It is a partial cross-sectional view of the charging frame. [Figure 6] It is a partial cross-sectional view of the charging frame.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0021] In the following, the direction in which the drum axis of the photoreceptor drum 20 extends is referred to as the "first direction". Also, the direction in which the opening 73 and the second guide rail 74 are arranged side by side is referred to as the "second direction". Further, the direction in which the non-contact surface 75 of the charging frame 33 and the holder 60 face each other is referred to as the "third direction".

[0022] The first direction and the second direction intersect each other. For example, the first direction and the second direction are perpendicular to each other. However, the intersection of the first direction and the second direction is not limited to perpendicularity. The second direction and the third direction intersect each other. For example, the second direction and the third direction are perpendicular to each other. However, the intersection of the second direction and the third direction is not limited to perpendicularity. The third direction and the first direction intersect each other. For example, the third direction and the first direction are perpendicular to each other. However, the intersection of the third direction and the first direction is not limited to perpendicularity.

[0023] <1. Configuration of the Image Forming Apparatus> FIG. 1 is a schematic diagram of an image forming apparatus 100. This image forming apparatus 100 is an electrophotographic printer. Specifically, the image forming apparatus 100 is a laser printer or an LED printer. As shown in FIG. 1, the image forming apparatus 100 includes a main body frame 101, a drum unit 2, and four developing cartridges 1.

[0024] The four developing cartridges 1 can be mounted on the drum unit 2. The drum unit 2 with the four developing cartridges 1 mounted can be mounted on the main frame 101. The drum unit 2 is mounted on the main frame 101 by moving relative to the main frame 101 in a direction that aligns the four developing cartridges 1.

[0025] The developing cartridge 1 contains toner. The developing cartridge 1 also has a developing roller 10. The drum unit 2 has four photoreceptor drums 20. When the developing cartridge 1 is installed in the drum unit 2, the developing roller 10 and the photoreceptor drums 20 come into contact.

[0026] The toner in the developing cartridge 1 is supplied to the photoreceptor drum 20 via the developing roller 10. The image forming apparatus 100 prints an image on the printing paper by transferring the toner from the photoreceptor drum 20 to the printing paper.

[0027] <2. Drum Unit Configuration> Figure 2 is a perspective view of the drum unit 2. As shown in Figure 2, the drum unit 2 comprises four photosensitive drums 20 and a drum frame 30.

[0028] <2-1. Photoconductor Drum> The photoreceptor drum 20 is a drum that can rotate about a drum axis extending in a first direction. Four photoreceptor drums 20 are arranged spaced apart from each other. The photoreceptor drum 20 has a cylindrical outer surface centered on the drum axis extending in the first direction. The outer surface of the photoreceptor drum 20 is covered with a photosensitive material.

[0029] <2-2. Drum Frame> The drum frame 30 supports four photoreceptor drums 20 so that they can rotate around the drum axis. The drum frame 30 has a first side frame 31, a second side frame 32, and four charging frames 33.

[0030] The first side frame 31 is located at one end of the drum frame 30 in the first direction. The first side frame 31 extends in the second and third directions. The first side frame 31 may be composed of multiple plates. For example, the first side frame 31 may be composed of a metal plate and a resin plate fixed to the metal plate.

[0031] The second side frame 32 is located at the other end of the drum frame 30 in the first direction. The second side frame 32 extends in the second and third directions. The second side frame 32 may be composed of multiple plates. For example, the second side frame 32 may be composed of a metal plate and a resin plate fixed to the metal plate.

[0032] The charging frame 33 is a frame that supports the charger 40, which will be described later. The charging frame 33 is made of resin. The four charging frames 33 are arranged with space between them. Each charging frame 33 extends in a first direction between the first side frame 31 and the second side frame 32. One end of the charging frame 33 in the first direction is connected to the first side frame 31. The other end of the charging frame 33 in the first direction is connected to the second side frame 32.

[0033] The four developing cartridges 1 are mounted on the drum frame 30. The four developing cartridges 1 can be individually attached to and detached from the drum frame 30. When the developing cartridges 1 are mounted on the drum frame 30, the developing cartridges 1 are located between the first side frame 31 and the second side frame 32 in a first direction.

[0034] Furthermore, with the developing cartridge 1 positioned on the drum frame 30, the developing roller 10 comes into contact with the photoreceptor drum 20. More specifically, the outer surface of the developing roller 10 comes into contact with the outer surface of the photoreceptor drum 20. This allows the toner carried on the outer surface of the developing roller 10 to be supplied to the photoreceptor drum 20.

[0035] <2-3. Charger and Cleaner Unit> The drum unit 2 is equipped with four chargers 40. The chargers 40 are devices that charge the outer surface of the photoreceptor drum 20. The four chargers 40 are spaced apart from each other. The chargers 40 are supported by a charging frame 33. When four developing cartridges 1 are mounted on the drum frame 30, the charging frame 33 and the chargers 40 are located between adjacent developing cartridges 1.

[0036] Figure 3 is a cross-sectional view of the drum unit 2 near the photoreceptor drum 20 and the charger 40. Figure 3 shows a cross-section perpendicular to the first direction. The charger 40 is a scorotron charger. As shown in Figure 3, the charger 40 has a charging wire 41 and a charging grid 42. The charging wire 41 and the charging grid 42 are located near the outer circumferential surface of the photoreceptor drum 20.

[0037] The charging wire 41 is a metal wire. The charging wire 41 extends in a first direction along the outer surface of the photoreceptor drum 20. The charging wire 41 is positioned at a distance from the outer surface of the photoreceptor drum 20. One end of the charging wire 41 in the first direction is fixed to one end of the charging frame 33 in the first direction. The other end of the charging wire 41 in the first direction is fixed to the other end of the charging frame 33 in the first direction.

[0038] The charging grid 42 is a metal plate having multiple holes. The charging grid 42 extends in a first direction along the outer circumferential surface of the photoreceptor drum 20. The charging grid 42 is positioned at a distance from the outer circumferential surface of the photoreceptor drum 20. The charging grid 42 is located between the outer circumferential surface of the photoreceptor drum 20 and the charging wire 41. One end of the charging grid 42 in the first direction is fixed to one end of the charging frame 33 in the first direction. The other end of the charging grid 42 in the first direction is fixed to the other end of the charging frame 33 in the first direction.

[0039] With the drum unit 2 mounted on the main frame 101, the charging wire 41 and the charging grid 42 are electrically connected to the control unit of the image forming apparatus 100. When the image forming apparatus 100 performs printing, the control unit applies a voltage between the charging wire 41 and the charging grid 42. This causes a corona discharge to occur between the charging wire 41 and the charging grid 42. As a result, the outer surface of the photoreceptor drum 20 becomes charged.

[0040] The drum unit 2 includes a cleaner unit 50. The cleaner unit 50 is a unit for cleaning the charged wire 41. The cleaner unit 50 is movable in a first direction relative to the charged wire 41. As shown in Figure 3, the cleaner unit 50 has a cleaner 51 and a holder 60. The cleaner 51 is made of a sponge, for example. The cleaner 51 is held in the holder 60. The cleaner 51 comes into contact with the charged wire 41. Specifically, the charged wire 41 is sandwiched between the cleaner 51. When the cleaner unit 50 moves in the first direction relative to the charged wire 41, the cleaner 51 rubs against the charged wire 41. This wipes away toner and dust adhering to the charged wire 41. Note that the cleaner 51 may be made of a material other than sponge, for example, resin or cloth.

[0041] Figure 4 is a partial perspective view of the charging frame 33. Figures 5 and 6 are partial cross-sectional views of the charging frame 33. Figures 5 and 6 show cross-sections of the charging frame 33 along the first and third directions.

[0042] As shown in Figure 3, a holding portion 52 is provided at one end of the holder 60 in the third direction. The holding portion 52 holds the cleaner 51. As shown in Figures 4 to 6, a handle 61 for operating the holder 60 is provided at the other end of the holder 60 in the third direction. The handle 61 is exposed on the surface of the charged frame 33. The handle 61 is, for example, a recess into which a user's finger can be inserted. The holder 60 is movable in the first direction along the charged wire 41 together with the cleaner 51, relative to the charged frame 33, between one end and the other end of the charged frame 33 in the first direction.

[0043] With the developing cartridge 1 removed from the drum frame 30, the user of the image forming apparatus 100 can insert their finger into the handle 61 and move the holder 60 in a first direction relative to the drum frame 30. When the holder 60 is moved in the first direction relative to the charged frame 33, the cleaner 51 also moves in the first direction relative to the charged frame 33 along with the holder 60. This cleans the charged wire 41.

[0044] As shown in Figure 4, the charging frame 33 has a guide slit 70. The guide slit 70 is a slit extending in a first direction. The guide slit 70 penetrates the charging frame 33 in a third direction. The holder 60 is inserted into the guide slit 70.

[0045] The charged frame 33 has two first guide rails 71. The first guide rails 71 are rails that extend in a first direction along the guide slit 70. One of the first guide rails 71 is formed along one edge of the guide slit 70 in a second direction. The other first guide rail 71 is formed along the other edge of the guide slit 70 in a second direction.

[0046] The first guide rail 71 has a first guide surface 711. The first guide surface 711 is a surface that extends in a first direction. The first guide surface 711 is capable of guiding the holder 60 in a first direction while in contact with the holder 60.

[0047] As shown in Figures 4 to 6, the charged frame 33 has a wall 72. The wall 72 is located at one end of the charged frame 33 in a first direction. The wall 72 faces the holder 60 in the first direction. When the charged wire 41 is not being cleaned, the holder 60 is located at one end of the charged frame 33 in the first direction. At this time, the holder 60 is in contact with the wall 72. This positions the holder 60 in a fixed position in the first direction.

[0048] As shown in Figure 4, the charging frame 33 has an opening 73. The opening 73 is a hole through which the holder 60 passes during the manufacturing process of the drum unit 2. In the first direction, the opening 73 is located between the two first guide rails 71 and one end of the charging frame 33 in the first direction. Also, in the first direction, the opening 73 is located between the guide slit 70 and one end of the charging frame 33 in the first direction. The opening 73 penetrates the charging frame 33 in the third direction. The guide slit 70 and the opening 73 are connected to each other. However, the width of the opening 73 in the second direction is greater than the width of the guide slit 70 in the second direction.

[0049] As shown in Figures 4 to 6, the charging frame 33 has a second guide rail 74. The second guide rail 74 extends in the first direction on one side of the opening 73 in the second direction. The second guide rail 74 is located on only one side of the opening 73 in the second direction.

[0050] The second guide rail 74 has a second guide surface 741. The second guide surface 741 is a surface that intersects with respect to the third direction and extends in the first direction. The position of the second guide surface 741 in the third direction is the same as, or further away from, the charged wire 41 than, the position of the first guide surface 711 in the third direction. The second guide surface 741 is capable of guiding the holder 60 in the first direction while in contact with the holder 60.

[0051] As described above, the first guide rail 71 does not extend into the range of the first direction where the opening 73 exists. However, the charging frame 33 of this embodiment has a second guide rail 74 on one side of the opening 73 in the second direction. Therefore, the holder 60 is guided by the second guide rail 74 between the first guide rail 71 and one end of the charging frame 33 in the first direction. This prevents the holder 60 from getting caught in the opening 73. Thus, the holder 60 can be moved smoothly in the first direction between the first guide rail 71 and one end of the charging frame 33 in the first direction. As a result, after cleaning, it is possible to prevent the holder 60 from returning to the position where it contacts the wall 72, and printing from starting while it is caught in the opening 73.

[0052] As shown in Figures 4 to 6, the charged frame 33 has a non-contact surface 75. The non-contact surface 75 is a surface that extends in the first direction between the second guide rail 74 and the other end of the charged frame 33 in the first direction. The position of the non-contact surface 75 in the third direction is closer to the charged wire 41 than the position of the second guide surface 741 in the third direction. While the holder 60 is guided by the first guide rail 71, the holder 60 does not come into contact with the non-contact surface 75. That is, while the holder 60 is guided by the first guide rail 71, the holder 60 faces the non-contact surface 75 at a distance in the third direction.

[0053] As shown in Figures 4 to 6, the second guide rail 74 has an inclined surface 742. The inclined surface 742 is the surface that connects the non-contact surface 75 and the second guide surface 741. The second guide surface 741 is further away from the charged wire 41 in the third direction than the non-contact surface 75. The position of the inclined surface 742 in the third direction gradually changes depending on its position in the first direction. More specifically, the inclined surface 742 is inclined so that as you approach the inclined surface 742 in the first direction, you move away from the charged wire 41 in the third direction.

[0054] The holder 60 is guided in a first direction along the inclined surface 742 between the non-contact surface 75 and the second guide surface 741. This allows the holder 60 to move smoothly between a position facing the non-contact surface 75 and a position in contact with the second guide surface 741.

[0055] In the first direction, the area where the first guide rail 71 is provided and the area where the second guide rail 74 is provided partially overlap. Specifically, one end of the first guide rail 71 and the inclined surface 742 are in the same position in the first direction. In this way, the holder 60 is always in contact with either the first guide surface 711, the inclined surface 742, or the second guide surface 741 from the first guide rail 71 to the second guide rail 74. Therefore, the holder 60 can be continuously guided by the first guide rail 71 and the second guide rail 74.

[0056] As shown in Figure 4, the charging frame 33 has a third guide rail 76. The third guide rail 76 is located between the opening 73 and one end of the charging frame 33 in a first direction. More specifically, the third guide rail 76 extends in a first direction between the opening 73 and the wall 72. The holder 60 is guided in a first direction by the third guide rail 76 between the opening 73 and the wall 72.

[0057] The third guide rail 76 has a tapered surface 761. The tapered surface 761 is located at the end of the third guide rail 76 furthest from the wall 72 in the first direction. The tapered surface 761 is inclined with respect to the first and third directions. More specifically, the tapered surface 761 is inclined to approach the opening 73 in the first direction and to approach the charged wire 41 in the third direction.

[0058] In this way, the tapered surface 761 prevents the holder 60 from catching on the corner of the third guide rail 76 when it moves from the second guide rail 74 to the third guide rail 76. Therefore, the holder 60 can move smoothly from the second guide rail 74 to the third guide rail 76.

[0059] <3. Variant> Although one embodiment has been described above, this disclosure is not limited to the above embodiment.

[0060] In the above embodiment, the second guide rail 74 was provided on only one side of the opening 73 in the second direction. However, the second guide rail 74 may be provided on both the one and the other side of the opening 73 in the second direction.

[0061] Furthermore, in the above embodiment, the drum unit 2 comprised a plurality of photoreceptor drums 20 and a plurality of charging wires 41. That is, the drum unit 2 included a first photoreceptor drum and a second photoreceptor drum separate from the first photoreceptor drum. The drum unit 2 also included a first charging wire for charging the outer surface of the first photoreceptor drum and a second charging wire separate from the first charging wire for charging the outer surface of the second photoreceptor drum.

[0062] However, the number of photoreceptor drums 20 and charging wires 41 in the drum unit 2 is not limited to the above embodiment. For example, the drum unit 2 may have one photoreceptor drum 20 and one charging wire 41 for charging the outer surface of the photoreceptor drum 20.

[0063] Furthermore, the elements that appear in the above embodiments and modifications may be combined or partially deleted as appropriate, to the extent that no inconsistencies arise. [Explanation of symbols]

[0064] 1: Developing cartridge 2: Drum Unit 10: Developing roller 20: Photoconductor drum 30: Drum frame 33: Charged frame 40: Charger 41: Electrostatically charged wire 42: Charging Grid 50: Cleaner Unit 51: Cleaner 52: Holding part 60: Holder 71: First guide rail 72: Wall 73 :Aperture 74: Second guide rail 75: Non-contact surface 76: Third guide rail 100: Image forming apparatus 711: First guide surface 741: Second guide surface 742: Inclined surface 761: Tapered surface

Claims

1. A photoreceptor drum that is rotatable with respect to a drum shaft extending in a first direction, A charging wire extending in the first direction along the outer surface of the photoreceptor drum, comprising a charging wire that charges the outer surface of the photoreceptor drum, A charging frame that supports the aforementioned charging wire, A drum unit equipped with, A cleaner for cleaning the aforementioned charged wire, A holder for holding the cleaner, comprising a holder that moves in the first direction along the charging wire together with the cleaner between one end and the other end of the charging frame in the first direction, Equipped with, The aforementioned charging frame is A first guide rail having a first guide surface that guides the holder in the first direction, An opening located between the first guide rail and one end of the charging frame in the first direction, A second guide rail having a second guide surface that guides the holder in the first direction, located on one side of the opening in a second direction intersecting the first direction, A drum unit characterized by having the following features.

2. A drum unit according to claim 1, The aforementioned charging frame is A non-contact surface located between the second guide rail and the other end of the charging frame in the first direction, and facing the holder at a distance in a third direction intersecting the first and second directions. It has, The aforementioned second guide rail is An inclined surface connecting the non-contact surface and the second guide surface, wherein the position in the third direction gradually changes according to the position in the first direction, and the inclined surface guiding the holder in the first direction. A drum unit characterized by having the following features.

3. A drum unit according to claim 1 or claim 2, The drum unit is characterized in that the second guide rail is located only on one side of the opening in the second direction.

4. A drum unit according to claim 1 or claim 2, The aforementioned charging frame is A wall located at one end in the first direction. It further possesses, A drum unit characterized in that, when the holder is located at one end of the charging frame in the first direction, the holder contacts the wall.

5. A drum unit according to claim 1, A drum unit characterized in that the position of the second guide surface in a third direction intersecting the first and second directions is the same as the position of the first guide surface in the third direction, or is further away from the charged wire than the position of the first guide surface in the third direction.

6. The drum unit according to claim 2, A drum unit characterized in that one end of the first guide rail and the inclined surface are located at the same position in the first direction.

7. A drum unit according to claim 1, The aforementioned charging frame is A third guide rail located between the opening and one end of the charging frame in the first direction. It further possesses, The aforementioned third guide rail is As it approaches the opening in the first direction, the tapered surface approaches the charged wire in the third direction intersecting the first and second directions. A drum unit characterized by having the following features.

8. A drum unit according to claim 1 or claim 2, The first photosensitive drum, which is the aforementioned photosensitive drum, A second photoreceptor drum, separate from the first photoreceptor drum, The charging wire is a first charging wire which charges the outer surface of the first photoreceptor drum, A second charging wire, separate from the first charging wire, which charges the outer surface of the second photoreceptor drum, A drum unit characterized by having the following features.

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