JP6123240B2 - Ground plate, end member, and photosensitive drum unit - Google Patents

Description

  The present invention relates to an end member provided in an image forming apparatus such as a laser printer or a copying machine, a photosensitive drum unit including the end member, and a ground plate disposed on the end member.

  Image forming apparatuses such as laser printers and copiers are provided with a photosensitive drum. The photosensitive drum is a member on which contents such as characters and figures to be transferred to a recording medium such as paper are formed. Such a photosensitive drum is configured such that a photosensitive layer is coated on the outer peripheral surface of a conductive substrate such as aluminum. The type of the photosensitive layer to be coated can be appropriately selected depending on the apparatus to which the photosensitive drum is applied.

  At both ends of the photosensitive drum, end portions for holding the photosensitive drum in the image forming apparatus main body (hereinafter sometimes referred to as “apparatus main body”) and rotating the photosensitive drum around the cylindrical axis. A member is mounted. Therefore, the photoconductive drum is disposed in the apparatus main body as a photoconductive drum unit in a state where end members are attached to both ends thereof.

  Conventionally, the end member is attached to the photosensitive drum by inserting a part (fitting portion) of the end member into the inside of the cylindrical photosensitive drum, and connecting the outer surface of the fitting portion to the inner side of the photosensitive drum. This is done by fixing the surface with an adhesive. Therefore, in this case, the fitting portion of the end member is inserted into the inside of the photosensitive drum, and the end member and the photosensitive drum are fixed by an adhesive.

  Here, the fixing of the end member to the photosensitive drum with an adhesive has a problem in adhesiveness such as peeling and durability against load torque (torque strength). This is considered to be due to the operating environment in which the photosensitive drum unit repeatedly rotates and stops and is heated during operation, and vibrations and changes in atmosphere due to transportation. As a specific example, since the thermal expansion coefficients of the end member, the photosensitive drum, and the adhesive are different from each other, a heat shock due to a thermal load occurs, and the adhesive surface is destroyed. Further, for example, polyacetal resin often used as an end member can reduce costs and has excellent slidability and noise reduction in gear driving, etc. Some resins have a problem in adhesion due to compatibility with the adhesive.

From this point of view, Patent Documents 1 and 2 disclose techniques for increasing the adhesion between the photosensitive drum and the end member.
According to Patent Document 1, a groove is provided in advance in the fitting portion of the resin end member at the time of injection molding, so that the adhesiveness can be improved by an anchor effect or the like.
Patent Document 2 discloses a technique for mechanically “crimping” and fixing after inserting an end member into a photosensitive drum.

By the way, the photosensitive drum is charged by applying voltage from the main body of the apparatus, and an image to be formed is developed by this charged state. Therefore, in each process such as image formation and transfer to a medium, charging and discharging are performed as necessary. Is done. When removing the charge, it is necessary to electrically connect the photosensitive drum to the apparatus main body side and take the ground.
Therefore, as disclosed in Patent Document 3, for example, a method is known in which a conductive member formed of metal or the like is disposed on an end member to obtain an electrically connected state.

JP 2001-83838 A Japanese Patent Laid-Open No. 06-230706 Japanese Patent No. 3352609

However, for example, many reused end members do not have a groove as described in Patent Document 1, and sufficient adhesion strength cannot be obtained if they are bonded as they are.
In addition, as described in Patent Document 2, fixing by caulking reduces productivity, and there is a possibility that the shake of the photosensitive drum and the roundness of the end portion of the product may also decrease.

  On the other hand, when an electrical connection is obtained as described in Patent Document 3, an electrical connection may not be stably obtained due to an alumite film formed on the inner surface of the photosensitive drum.

  That is, when the end member is mounted on the photosensitive drum, stable fixing and improvement in electrical connection are required.

  In view of the above problems, an object of the present invention is to provide an end member that enables stable fixing and energization of the end member and the photosensitive drum. Also provided are a photosensitive drum unit including the end member and a ground plate provided in the end member.

  The present invention will be described below. Here, for ease of understanding, reference numerals of the drawings are given in parentheses, but the present invention is not limited to this.

According to the first aspect of the present invention, there is provided an end member (20) attached to the end portion of the photosensitive drum (11), and a fitting portion (24) which is a portion to be inserted inside the photosensitive drum. And an earth plate (30) disposed in contact with the fitting portion, and the earth plate is a surface of the fitting portion that does not contact the photosensitive drum. in it a base (31) arranged on the end face, a holding piece which is provided so as to extend in a direction away from the base portion to the base portion (32), provided with, the holding piece, the fitting portion on the surface thereof The holding member is an end member that is provided with locking means having a rough surface for locking to the surface, and that the holding piece is in contact with so that at least a portion thereof overlaps a part of the outer peripheral surface of the fitting portion. .

The invention of claim 2 is provided at the end member according to claim 1 (20), a projection provided so as to protrude from the locking means (33) retaining piece (32).

The invention described in claim 3 includes a cylindrical photosensitive drum (11) and an end member (20) attached to the end of the photosensitive drum, and the end member is a member of the photosensitive drum. An end member main body (21) having a fitting portion (24) which is a portion to be inserted inside, and a ground plate (30) disposed in contact with the fitting portion, A base portion (31) disposed on an end surface of the fitting portion that does not contact the photosensitive drum, and a holding piece (32) provided on the base portion so as to extend away from the base portion. The holding piece is provided with locking means having a rough surface for locking to the surface of the fitting portion and / or the photosensitive drum on the surface thereof, and at least a part of the holding piece is provided on the photosensitive drum. Between the inner surface and a part of the outer peripheral surface of the fitting portion, and is in contact with the photosensitive drum. It is a photosensitive drum unit (10).

The invention of claim 4 is provided in the photosensitive drum unit (10) according to claim 3, the projection provided so as to protrude from the locking means (33, 34) is holding piece (32).

  According to the present invention, the end member can be stably held at the end of the photosensitive drum, and a stable electrical conductivity can be obtained.

2 is an external perspective view of the photosensitive drum unit 10. FIG. 3 is an exploded perspective view of an end member 20. FIG. 3 is an exploded sectional view of an end member 20. FIG. 4A is a perspective view of the end member 20, and FIG. 4B is a cross-sectional view of the end member 20. As shown in FIG. 2 is a view focusing on a portion where an end member 20 is arranged in a cross section of the photosensitive drum unit 10. FIG. FIG. 6A is an external view for explaining the posture in which the energizing shaft 1 is inserted into the photosensitive drum unit 10, and FIG. 6B is a cross-sectional view for explaining the posture in which the energizing shaft 1 is inserted into the photosensitive drum unit 10. is there. FIG. 7A is a perspective view of the ground plate 130, and FIG. 7B is a cross-sectional view of the ground plate 130.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments.

FIG. 1 is a view for explaining one embodiment, and is an external perspective view of a photosensitive drum unit 10 having an end member 20.
The photosensitive drum unit 10 is mounted on an image forming apparatus such as a laser printer or a copying machine, and characters, graphics, and the like to be transferred to a recording medium such as paper are formed. As can be seen from FIG. 1, the photosensitive drum unit 10 includes a photosensitive drum 11, an end member 20, and a lid member 40.

  The photosensitive drum 11 is a member in which a photosensitive layer is coated on the outer peripheral surface of a cylindrical substrate. The base body is formed of a cylindrical conductive material such as aluminum or aluminum alloy. The photosensitive layer formed on the outer peripheral surface of the substrate is not particularly limited, and a known layer can be applied depending on the purpose. Here, when an aluminum alloy is used as the substrate, the type thereof is not particularly limited, but is a 6000 series, 5000 series, or 3000 series aluminum alloy that is often used as a conductive substrate of a photosensitive drum. It is preferable.

  The substrate can be manufactured by forming a cylindrical shape by cutting, extruding, drawing, or the like. The photosensitive drum 11 can be produced by laminating the photosensitive layer on the outer peripheral surface of the substrate.

  The end member 20 is one form of the end member, is attached to one end portion of the end portions of the photosensitive drum 11, and includes an end member main body 21 and a ground plate 30. 2 is an exploded perspective view of the end member 20, and FIG. 3 is an exploded sectional view in the axial direction along the line III-III shown in FIG.

The end member main body 21 is a member that receives the rotational driving force from the rotational driving shaft of the image forming apparatus directly or via another member and rotates the photosensitive drum unit 10 itself. Therefore, the end member main body 21 is provided with a gear portion 22 provided with a gear for transmitting a rotational force. In addition, this rotational force can be transmitted to other rollers (for example, a charging roller) adjacent by the gear.
The end member main body 21 has a cylindrical shape as a whole, and the end member main body 21 has a gear portion 22, a contact wall portion 23, and a fitting portion 24 arranged in the cylindrical axis direction.

The gear part 22 is a part where a gear is formed on the outer peripheral surface of the end member main body 21, and the rotational driving force from the apparatus main body is transmitted by the gear. Accordingly, the type of gear is not particularly limited, and may be a helical gear or a spur gear. Moreover, although the example in which the gear portion is provided is shown in the present embodiment, the end member main body is not necessarily provided with the gear portion. Further, a gear may be provided on the lid member 40 side described later.
In the present embodiment, the gear is exemplified as the transmission means for the rotational driving force, but other means may be used as long as the rotational force can be transmitted from the apparatus main body. For example, a configuration in which a coupling is configured by engaging with the drive shaft of the apparatus main body by providing a bearing member having a non-circular cross section can be exemplified.

  The contact wall portion 23 is a portion formed to have a larger diameter on the outer peripheral side than the fitting portion 24. As shown in FIG. 1 and FIGS. 5 and 6 described later, the contact wall portion 23 is in a posture in which the end member 20 is mounted on the photosensitive drum 11, and the surface of the contact wall portion 23 is the surface of the photosensitive drum 11. It arrange | positions so that an end surface may be contacted. As a result, the insertion depth of the end member 20 into the photosensitive drum 11 is restricted.

The fitting portion 24 is one end side of the end member and is a portion that is inserted inside the photoconductor drum 11 and fixes the end member 20 to the photoconductor drum 11. Accordingly, the outer diameter of the fitting portion 24 is substantially the same as the inner diameter of the photosensitive drum 11 as long as it can be inserted inside the cylindrical shape of the photosensitive drum 11.
When the photosensitive drum unit 10 is provided in a process cartridge mounted on the apparatus main body, it is necessary to reliably and repeatedly transmit the rotational driving force from the apparatus main body via the gear unit 22. Therefore, the end member 20 is firmly coupled to the photosensitive drum so as not to drop off or loosen.

  In addition, as can be seen from the cross-sectional view of FIG. 3, a part of the inside of the cylinder is closed on the inner side which is the cylinder of the end member main body 21. ), See FIG. 6B.) A hole 21a is provided.

Such an end member main body 21 is not necessarily limited, but is preferably formed of a crystalline resin. If it is a crystalline resin, when it is injection-molded using a mold, the flow is good, so the molding processability is good, and it is released from the mold by crystallization and solidification without cooling to the glass transition point. Therefore, productivity can be greatly improved. In addition, the crystalline resin is excellent in heat resistance and solvent resistance, has good friction wear resistance and sliding property, and is also preferable as a material applied to the end member from the viewpoint of rigidity and hardness.
Examples of the crystalline resin include polyethylene, polypropylene, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, methylpentene, polyphenylene sulfide, polyether ether ketone, polytetrafluoroethylene, and nylon.
Among these, it is preferable to use polyacetal from the viewpoint of moldability.

  Since the end member 20 does not necessarily require an adhesive when mounted on the photosensitive drum 11 as will be described later, even if the fitting portion 24 of the end member main body 21 is provided with a groove in advance, It may not be provided.

  As can be seen from FIGS. 2 and 3, the ground plate 30 is a plate-like member deformed into a predetermined shape, and is formed of a conductive material. As a result, as will be described later, the end member 20 can be stably fixed to the photosensitive drum 11 and stable energization between the photosensitive drum 11 and the apparatus main body can be ensured. The material to be used is not particularly limited as long as it has electrical conductivity, but is preferably a metal material from the viewpoint of low electrical resistance, and examples thereof include stainless steel alloys and copper alloys.

The ground plate 30 includes a base 31, a holding piece 32, and locking means 33 and 34.
The base portion 31 is a portion that becomes the base portion of the ground plate 30, and has a flat plate shape in this embodiment. However, it does not necessarily have to be flat, and may be provided with unevenness or may have some other three-dimensional shape.
The base 31 is sized to be included inside the photosensitive drum 11, and is provided with a through hole 31 a into which the current-carrying shaft 1 (see FIGS. 6A and 6B) on the apparatus main body side can be inserted. ing. In the through hole 31a, two plate-like contact plates 31b extending from the edge of the through hole 31a in the direction closing the through hole 31a are formed.

  The holding piece 32 is a piece extending from the base portion 31 to the outside of the base portion 31. In this embodiment, a plurality of holding pieces 32 are arranged at predetermined intervals on the outer peripheral edge portion of the base portion 31. As will be described later, the holding piece 32 is in contact with at least a part (tip portion) of the holding member 32 so as to overlap the outer peripheral surface of the fitting portion 24 of the end member main body 21, and Positioned to be sandwiched between the faces. Therefore, the holding piece 32 has a size (length) positioned in this way.

  The locking means 33 is provided on the holding piece 32 and is a means for locking the ground plate 30 by acting on the end member main body 21 side in a posture in which the end member 20 is mounted on the photosensitive drum 11. In this embodiment, the locking means 33 is a protrusion that protrudes toward the end member main body 21. Further, in this embodiment, the locking means 33 are arranged at every other holding piece 32 (two locking means 33 appear in FIG. 2, and the others are not visible as blind spots. ).

  The locking means 34 is provided on the holding piece 32 and is a means for locking the ground plate 30 by acting on the photosensitive drum 11 side in a posture in which the end member 20 is mounted on the photosensitive drum 11. In this embodiment, the locking means 34 is a protrusion that protrudes toward the side opposite to the end member main body 21. Further, in this embodiment, the locking means 34 is arranged on the holding piece 32 where the locking means 33 is not arranged among the plurality of holding pieces 32 (two locking means 34 appear in FIG. 2). Others are blind spots and cannot be seen.)

In the present embodiment, the protrusions are exemplified as the locking means 33 and 34, but the end member main body 21 and the photosensitive drum 11 may be locked with a high frictional force. For example, the surface of the holding piece 32 may be roughened by mechanical treatment or chemical treatment to form a rough surface. Examples of the mechanical treatment include a method of scratching the surface with a blade or the like to raise burrs, shot blasting, and the like. On the other hand, examples of the chemical treatment include etching. These various means may be used in combination.
However, these various treatments are preferably performed in consideration of the electrical conductivity (particularly surface electrical conductivity) between the holding piece and the photosensitive drum. This is because ensuring stable conductivity is also important.

  The end member main body 21 and the ground plate 30 as described above are combined as follows to form the end member 20. A diagram is shown in FIG. 4A is a perspective view, and FIG. 4B is a cross-sectional view taken along the line IVb-IVb in FIG. 4A.

  As can be seen from FIG. 4A and FIG. 4B, among the end surfaces of the end member main body 21, the grounding plate is closed so as to block the end surface on the fitting portion 24 side (the surface not in contact with the photosensitive drum 11). 30 bases 31 are stacked. And the holding piece 32 is arrange | positioned along the outer surface of the fitting part 24 so that it may extend toward the direction of the contact wall part 23. FIG. As shown in FIG. 4 (b), the ground plate 30 is engaged by engaging the projection, which is the engagement means 33 of the holding piece 32, so as to be caught on the outer peripheral surface of the fitting portion 24 of the end member main body 21. It is held by the member main body 21.

Returning to FIG. 1, the lid member 40 will be described. The lid member 40 is an end member that is attached to the end of the photosensitive drum 11 opposite to the side where the end member 20 is disposed. The lid member 40 is not provided with a gear portion, but is one form of an end member. Therefore, the material is the same as that of the end member 20.
The lid member 40 includes a disc-shaped bearing portion 40a and a fitting portion 40b (indicated by a broken line in perspective in FIG. 1) that protrudes from the surface of the bearing portion 40a to the inside of the photosensitive drum 11. I have. In the lid member 40, a fitting portion 40 b that is fitted inside the cylinder of the photosensitive drum 11 and a bearing portion 40 a that is arranged so as to cover one end surface of the photosensitive drum 11 are formed coaxially. Here, the bearing portion 40a has a disk shape that covers the end surface of the photosensitive drum 11, and includes a portion that receives the shaft.

  Although the example in which the ground plate 30 is disposed on the end member 20 has been described in the present embodiment, the ground plate 30 may be disposed on the lid member 40 side. Even in that case, the same ground plate as described above can be applied.

  The photosensitive drum unit 10 is manufactured by combining the members described above, for example, as follows. FIG. 5 shows an axial cross section of a portion where the end member 20 is mounted on one end side of the photosensitive drum 11.

First, the ground plate 30 is attached to the end member main body 21 to obtain the state shown in FIG. According to this, the ground plate 30 is combined with the end member main body 21 relatively stably by the holding piece 32 and the locking means 33.
Next, the end member 20 is inserted by an arbitrary press-fitting means so that the fitting portion 24 of the end member 20 is inserted from an opening portion on one end side of the photosensitive drum 11. At that time, the contact wall 23 is inserted until it contacts the end surface of the photosensitive drum 11. For example, air, hydraulic pressure, or an electric cylinder can be used as the press-fitting means. In that case, it is possible to perform assembly with high accuracy by performing press-fitting by combining the press-fitting direction, the end member axis, and the photosensitive drum axis. As a result, the state shown in FIG. 5 is obtained. At this time, since the holding piece 32 of the ground plate 30 is disposed along the outer peripheral surface of the fitting portion 24 as described above, the holding piece 32 is interposed between the fitting portion 24 and the inner surface of the photosensitive drum 11. It contacts the inner surface of the photosensitive drum so as to be sandwiched. Further, the protrusions that are the locking means 34 of the holding piece 32 are locked so as to be caught on the inner surface of the photosensitive drum 11.

  As described above, at least a part of the ground plate 30 is sandwiched between the outer peripheral surface of the fitting portion 24 of the end member main body 21 and the inner surface of the photosensitive drum 11, thereby the end member. 20 is stably held on the photosensitive drum 11. Further, the adhesiveness between the photosensitive drum 11 and the ground plate 30 is high in the sandwiched portion, and the conduction property is also stabilized.

  Further, if the latching means is provided at the sandwiched portion of the ground plate 30 as in this embodiment, the end member main body 21, the ground plate 30, and the photosensitive drum 11 are engaged by the latching means. Fit and hold stronger. In addition, since the ground plate 30 and the photosensitive drum 11 are more strongly in contact with each other at the portion of the locking means, the stability of the conductivity is improved.

In the present embodiment, an adhesive for bonding the end member 20 and the photosensitive drum 11 can be made unnecessary. As a result, it is possible to prevent the occurrence of problems due to the scattering of the adhesive during the production of the photosensitive drum unit. However, this does not prevent the use of the adhesive, and for example, the adhesive may be used in a small amount.
When using an adhesive, it is not particularly limited, but it is preferable to use a cyanoacrylate, polyurethane, or acrylic resin. Among these, a cyanoacrylate-based adhesive having a high curing rate is preferable because it is rapidly cured by surrounding moisture.

  On the other hand, the lid member 40 is fixed to the opposite side of the end portion of the photosensitive drum 11 from the end portion to which the end member 20 is attached. A known method can be applied to this. However, as described above, the ground plate 30 can also be arranged for the lid member 40. That is, at this time, the ground plate 30 may be used as a fixing means for the lid member 40 that does not consider energization.

Next, an aspect in a scene where the energizing shaft 1 arranged on the apparatus main body side is inserted into the photosensitive drum unit 10 will be described. FIG. 6 shows a diagram for explanation. 6A is an external view showing the side where the end member 20 is arranged in the photosensitive drum unit 10, and FIG. 6B is an axial sectional view from the same viewpoint as FIG. 6A.
As can be seen from FIGS. 6A and 6B, the energizing shaft 1 on the apparatus main body side extends through the inside of the end member main body 21 which is a cylinder and protrudes from the other end side. At this time, the energizing shaft 1 passes through the hole 21 a of the end member main body 21 and the through hole 31 a of the ground plate 30. Since the contact plate 31b is provided in the through hole 31a as described above, the energizing shaft 1 passes through the through hole 31a so as to push the contact plate 31b, and the contact plate 31b contacts the energizing shaft 1.
With such a configuration, the photosensitive drum 11, the ground plate 30, and the energizing shaft 1 are electrically connected. A stable electrical contact state can be obtained by the above-described configuration of the end member 20.

  FIG. 7 is a diagram for explaining another embodiment. FIG. 7A is an external perspective view of the ground plate 130, and FIG. 7B is a cross-sectional view taken along line VIIb-VIIb in FIG. Since the configuration other than the ground plate 130 is the same as described above, the ground plate 130 will be described here, and the other configurations will be omitted.

The ground plate 130 includes a base 31 and a holding piece 132. Here, the base 31 is the same as the ground plate 30.
In this embodiment, the holding piece 132 is formed by a cylindrical body provided so as to stand upright from the outer periphery of the base portion 31. Therefore, the ground plate 130 has a shallow bottomed cylindrical shape in which the base 31 is the bottom and the holding piece 132 is the wall. In this embodiment, rough surfaces are formed as locking means on both surfaces of the holding piece 132.

  Such a ground plate 130, an end member using the ground plate 130, and the photosensitive drum unit also have the same effects as described above.

DESCRIPTION OF SYMBOLS 10 Photosensitive drum unit 11 Photosensitive drum 20 End member 21 End member main body 22 Gear part 23 Contact wall part 24 Fitting part 30 Ground plate 31 Base part 32 Holding piece 33 Locking means 34 Locking means 40 Cover member 130 Ground plate 132 Holding piece

Claims (4)

An end member attached to the end of the photosensitive drum,
An end member main body having a fitting portion which is a portion to be inserted inside the photosensitive drum;
A ground plate disposed in contact with the fitting portion;
The ground plate is
A base portion disposed on an end surface which is a surface not in contact with the photosensitive drum among the fitting portions;
A holding piece provided on the base portion so as to extend in a direction away from the base portion,
Wherein the holding piece, with the locking means is provided with a rough surface for engaging the surface of the fitting portion on the surface thereof, wherein the holding piece has at least a portion of the outer peripheral surface of the fitting portion In contact with some part,
End member. End member according to claim 1, further comprising a protrusion, wherein the locking means is provided so as to protrude from the holding piece. A cylindrical photosensitive drum;
An end member attached to an end of the photosensitive drum,
The end member is
An end member main body having a fitting portion which is a portion to be inserted inside the photosensitive drum;
A ground plate disposed in contact with the fitting portion;
The ground plate is
A base portion disposed on an end surface which is a surface not in contact with the photosensitive drum among the fitting portions;
A holding piece provided on the base portion so as to extend in a direction away from the base portion,
Wherein the holding piece, with the locking means is provided with a rough surface for engaging at least one of a surface and the photosensitive drum of the fitting portion on the surface thereof, wherein the holding piece at least partly the A photosensitive drum unit that is disposed between the inner surface of the photosensitive drum and a part of the outer peripheral surface of the fitting portion and is in contact with the photosensitive drum. Photosensitive drum unit according to claim 3, wherein the locking means comprises a projection provided so as to protrude from the holding piece.

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