JP2015041088A - End member, photosensitive drum unit, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an end part member that sufficiently transmits rotation driving force, suppresses a scratch or a bruise occurring in a driving shaft and a bearing member, makes an attachment/detachment between a device main body and a photoreceptor drum smooth, facilitates alignment of a shaft line between the driving shaft and the bearing member, and is excellent in productivity.SOLUTION: An end part member 20 is arranged at an end part of a photoreceptor drum unit removable with respect to an image formation device main body, and is provided with a bearing member 30 having a convex shape. The bearing member 30 has no undercut part in a direction along a shaft line of an outer peripheral surface, and in a cross section orthogonal to the direction where the shaft line extends, an outer peripheral shape is polygonal. The polygon contacts with an inner surface of a concave part, and comprises: at least three rotation force transmission apex parts being apex parts that transmits hook rotation force to the concave part upon a rotation of the driving shaft; a rotation force transmission side being a side at least partially in contact with the concave part; and at least one alignment protrusion which is arranged at a portion other than the rotation force transmission side between the rotation force transmission apex parts, and of which a tip is a protrusion in contact with the concave part.

Description

  The present invention relates to a process cartridge mounted on an image forming apparatus such as a laser printer or a copying machine, a photosensitive drum unit included in the process cartridge, and an end member provided in the photosensitive drum unit.

2. Description of the Related Art Image forming apparatuses such as laser printers and copiers include a process cartridge that is detachable from a main body of the image forming apparatus (hereinafter sometimes referred to as “apparatus main body”).
The process cartridge is a member that forms contents to be represented such as characters and figures in a posture mounted on the apparatus main body and transfers the contents to a recording medium such as paper. For this purpose, the process cartridge includes a photosensitive drum on which the content to be transferred is formed, and a charging unit and a developing unit for forming the content to be transferred to the photosensitive drum.

  For the process cartridge, the same process cartridge is attached to or detached from the apparatus main body for maintenance, or an old process cartridge is detached from the apparatus main body and a new process cartridge is attached to the apparatus main body. Such a process cartridge can be attached and detached by the user of the image forming apparatus by himself / herself.

In addition, the photosensitive drum included in the process cartridge needs to be rotated during its operation. Therefore, an end member (bearing member) is connected to the photosensitive drum so that the drive shaft of the apparatus main body is engaged directly or via another member, and the photosensitive drum rotates by receiving a rotational force from the drive shaft. Is provided.
On the other hand, in order to attach and detach the process cartridge to and from the apparatus main body as described above, the engagement (disengagement) between the drive shaft of the apparatus main body and the bearing member provided on the photosensitive drum is re-engaged. It is necessary to match.

In Patent Documents 1 and 2, a drive shaft that moves in the axial direction is provided on the apparatus main body side, and the drive shaft has a polygonal cross section, and a twisted hole is formed in the direction along the axis. On the photosensitive drum side, a technique is disclosed that includes a polygonal columnar protrusion that is inserted into a twisted hole of a drive shaft as a bearing member and transmits a driving force. The protrusion described in Patent Document 1 has a columnar shape that is twisted corresponding to the twisted hole of the drive shaft. On the other hand, the protrusions described in Patent Document 2 are columnar shapes that are not twisted.
Each of the techniques described in Patent Documents 1 and 2 aims to improve the rotational accuracy of the photosensitive drum and reliably transmit the driving force from the apparatus main body to the photosensitive drum.

JP-A-8-328449 Japanese Patent Laid-Open No. 10-153941

However, in the technique including a twisted hole and a twisted columnar protrusion corresponding to the twisted hole as described in Patent Document 1, when a twisted columnar protrusion is produced by injection molding, rotation is given in accordance with the twist of the columnar protrusion. And the mold structure tends to be complex and large. Further, since the mold structure becomes complicated and large, it is difficult to produce a mold that can simultaneously mold a plurality of end members having twisted columnar protrusions.
Further, in the technique described in Patent Document 1, when the process cartridge is detached from the apparatus main body, it is necessary to provide rotation in a direction opposite to the driving direction when removing the twisted columnar protrusion from the twisted hole of the drive shaft. There is. Thereby, separation may not be performed smoothly.

  In addition to this, the bearing member provided with the columnar protrusions as described in Patent Documents 1 and 2 can smoothly engage and disengage from the drive shaft of the apparatus body while having sufficient rotation transmission accuracy. That wasn't always enough. For example, when the bearing member has a shape in which the contact portion between the drive shaft and the bearing member is reduced in order to smoothly engage and disengage the drive shaft of the apparatus main body, the driving force may not be transmitted properly. In addition, even if the driving force can be transmitted, the contact area between the two is reduced, the force is concentrated and scratches become dents, resulting in functional and appearance defects, and the drive shaft and bearing member. There was a case that the axis line of was not matched.

  Therefore, in view of the above problems, the present invention sufficiently transmits the rotational driving force, suppresses scratches and dents generated in the drive shaft and the bearing member, and the attachment and detachment between the apparatus main body and the photosensitive drum is smooth. An object of the present invention is to provide an end member that can be aligned with the bearing member and is excellent in productivity. Further, a photosensitive drum unit using the end member and a process cartridge are provided.

  The present invention will be described below.

  According to a first aspect of the present invention, there is provided a photosensitive drum unit that is detachably attached to an image forming apparatus main body provided with a drive shaft having a concave portion that is a hole having a substantially triangular cross section and twisted in the axial direction. It is an end member disposed at the end, and is provided with a convex bearing member that can be engaged and disengaged in the recess, and the bearing member has no undercut portion in the direction along the axis of the outer peripheral surface, Of the cross section orthogonal to the direction in which the axis extends, the outer peripheral shape is a polygon, and the polygon is at least three parts that are in contact with the inner surface of the recess and are caught by the recess when the drive shaft rotates and transmit the rotational force. Rotational force transmission top, a rotational force transmission side that is at least a part that contacts the recess, and a protrusion that is disposed between the adjacent rotational force transmission tops other than the rotational force transmission side and whose tip contacts the recess. At least one Aligning includes projections and the an end portion member.

  According to a second aspect of the present invention, in the end member according to the first aspect, the aligning protrusion is provided at a position where the tip of the aligning protrusion is in contact with the center of the side that is a triangle of the recess.

  According to a third aspect of the present invention, in the end member according to the first aspect, the aligning protrusion is provided at a position where the tip of the aligning protrusion contacts the hypotenuse of the wall surface which is a twisted triangle of the recess. ing.

According to a fourth aspect of the present invention, in the end member according to any one of the first to third aspects, the polygon is a polygon having 10 or more corners.
Here, the “polygon” is a concept including a convex polygon and a concave polygon.

According to a fifth aspect of the present invention, in the end member according to any one of the first to fourth aspects, in the cross section of the bearing member, a hexagonal shape in which each of the three rotational force transmission tops is a vertex that is not adjacent to each other. The radius of the circumscribed circle of the smallest triangle including three sides that are not adjacent to each other among the sides constituting the hexagon is defined as R _1p, and the radius of the circumscribed circle of the smallest triangle including the substantially triangular sectional shape of the recess is defined as When R _1h ,
0.85 ≦ R _1p / R _1h ≦ 1.07
It is.

According to a sixth aspect of the present invention, in the end member according to the fifth aspect, the shape of the hexagonal cross section has a corrected shape, and the corrected shape is adjacent to the hexagonal cross section. One set that does not contribute to the transmission of rotational force among the three sides that do not contribute is a shape in which the inclination angle is changed from the correction angle to the correction angle θ ₁ before and after the correction, and the correction angle θ ₁ is set such that R _1p / R _1h is 0. In the range of 85 to 0.93, θ ₁ is 0.1 ° to 10 °.

According to a seventh aspect of the present invention, in the end member according to the fifth or sixth aspect, the ridge line and the bearing at the opening of the concave portion are in a posture in which the concave portion and the bearing member can be engaged with each other to transmit the rotational force. The contact length with the member is L _c , the angle formed between the contact bearing member portion and the ridge line of the recess is θ _m , and the correction angle that is changed from the hexagon before the change to change θ _m is θ ₂ When R _1p / R _1h is 0.85 or more and 0.93 or less, θ ₂ is 0.1 ° or more and 10 ° or less.

According to an eighth aspect of the present invention, in the end member according to the fifth or sixth aspect, the ridge line and the bearing at the opening of the concave portion are in a posture in which the concave portion and the bearing member can be engaged with each other to transmit the rotational force. The contact length with the member is L _c , the angle formed between the contact bearing member portion and the ridge line of the recess is θ _m , and the correction angle that is changed from the hexagon before the change to change θ _m is θ ₂ When R _1p / R _1h is 0.96 or more and 1.07 or less, θ ₂ is −10 ° or more and −0.1 ° or less.

  According to a ninth aspect of the present invention, there is provided a cylindrical photosensitive drum, and the end member according to any one of the first to eighth aspects, which is attached to at least one end of the photosensitive drum. And a photosensitive drum unit.

  According to a tenth aspect of the present invention, there is provided the photosensitive drum unit according to the ninth aspect, a charging roll for charging the photosensitive drum of the photosensitive drum unit, and a developing roll for developing the electrostatic latent image on the photosensitive drum. A process cartridge.

  According to the present invention, the rotational driving force from the apparatus main body is transmitted to the photosensitive drum, and the apparatus main body and the photosensitive drum unit are smoothly attached and detached. It is possible to obtain a state in which the axis line is aligned. Further, when the rotational driving force is transmitted, it is possible to suppress deformation such as scratches and dents on the drive shaft and the bearing member. On the other hand, the productivity is good because the bearing member has no undercut portion.

FIG. 3 is a schematic diagram illustrating an image forming apparatus with a diagram illustrating one embodiment. FIG. 2A is a perspective view showing one end side of the drive shaft, and FIG. 2B is a front view showing one end side of the drive shaft. It is a figure explaining the shape of a recessed part. FIG. 4A is a front view showing another example of the recess, and FIG. 4B is a diagram for explaining the shape of another example of the recess. It is the figure which showed notionally the structure of the process cartridge. 2 is an external perspective view of a photosensitive drum unit. FIG. It is an external appearance perspective view of an edge part member. FIG. 8A is a front view of the end member, and FIG. 8B is a side view of the end member. It is a figure explaining the shape of a bearing member. It is a diagram illustrating a hexagonal T ₄ that defines the bearing member. Is a perspective view illustrating the engagement between the temporary bearing member by hexagonal T ₄ and the recess of the drive shaft. Is a diagram of the axial cross-section schematically illustrating a view for explaining the engagement between the recess of the drive shaft temporary bearing member by hexagonal T _4. It is a front view illustrating the engagement between the temporary bearing member by hexagonal T ₄ and the recess of the drive shaft. FIG. 14A is a diagram illustrating a state before the correction angle θ ₂ is applied, and FIG. 14B is a diagram illustrating the correction angle θ ₂ . FIG. 15A is a diagram illustrating a state before the correction angle θ ₁ is applied, and FIG. 15B is a diagram illustrating the correction angle θ ₁ . It is a front view explaining engagement of the bearing member 30 and the recessed part 52. FIG. This is a bearing member 130 of an example in which the depressions 37, 38, 39 are not provided. 18A shows a bearing member 230 in which only the alignment protrusion 34 is provided, and FIG. 18B shows a bearing member 330 in which a depression that is curved with respect to the side where the alignment protrusion is not provided is provided. . The bearing member 430 is provided with two alignment protrusions 34 and 35. This is a bearing member 530 having three alignment protrusions 534, 535, and 536 and apexes 534a, 534a, and 536a.

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

  FIG. 1 is a diagram illustrating one embodiment, and a process cartridge 3 included in the image forming apparatus 1 and an image forming apparatus main body 2 (hereinafter referred to as “apparatus main body 2”) to which the process cartridge 3 is attached may be described. It is the perspective view which showed typically. As shown in FIG. 1, the image forming apparatus 1 includes an apparatus main body 2 and a process cartridge 3. The process cartridge 3 can be attached to and detached from the apparatus main body 2 by moving in the direction indicated by A in FIG.

  Here, the apparatus main body 2 has a drive shaft 51 described below. For other parts, known structures can be used.

  First, the drive shaft 51 provided in the apparatus main body 2 will be described. FIG. 2 shows an end portion of the drive shaft 51 provided in the apparatus main body 2 that applies a rotational driving force to the photosensitive drum unit 10 on the side that engages with the bearing member 30 (see FIG. 7). FIG. 2A is a perspective view, and FIG. 2B is a front view. In FIG. 2A and FIG. 2B, a part of the recess 52 is seen through and indicated by a broken line. The opposite end of the drive shaft 51 is directly or indirectly connected to the drive source of the apparatus main body 2.

  As can be seen from FIGS. 2A and 2B, a recess 52 is provided at the end of the drive shaft 51. The recess 52 has a substantially equilateral triangular cross-section in a direction orthogonal to the direction in which the axis of the drive shaft 51 extends, and the axis is formed at a predetermined angle as it advances from the end face of the drive shaft 51 in the direction (depth direction). It is a hole having a shape that twists to the center. In addition, a cylindrical protrusion 53 is erected from the bottom of the recess 52 along the axis from the axial position of the drive shaft 51. Accordingly, the recess 52 has an opening at the end of the drive shaft 51 and is formed in a container shape having a depth in the direction in which the axis extends and having a bottom.

As can be seen from FIG. 2B, when the recess 52 is seen through from the front in the axial direction, the triangle (T ₁ ) formed in the opening of the recess 52 and the bottom of the recess 52 are formed. The triangle (T ₂ ) appears to overlap two triangles rotated about the axis. The following features are defined from this form. FIG. 3 shows a diagram for explanation. FIG. 3 focuses on the recess 52 from the same viewpoint as FIG.

In FIG. 2B and FIG. 3, the triangle formed at the opening of the recess 52 is denoted by reference symbol T ₁ , and the triangle formed at the bottom of the recess 52 is denoted by reference symbol T ₂ . Here, when the concave portion 52 is viewed from the viewpoint of FIG. 3, a shape T ₃ having an apex at the intersection of T ₁ and T ₂ is formed inside the _two triangles T ₁ and T ₂ ( shape _{T 3} is indicated by a thick line in FIG. 3.). In this embodiment the shape T ₃ is hexagonal. The following shape is defined from such a recess 52.

The circumscribed circle of the triangles T ₁ and T ₂ is C _1h, and the radius of the circumscribed circle C _1h is R _1h . In this embodiment, T ₁ and T ₂ are formed by perfect triangles, but the shape of the recesses may be formed by polygons in which the vertices of the triangles are cut off. In this case, the triangles T ₁ and T ₂ are defined by the smallest triangle including the polygon.

Rotation angle of the triangle _{T 1} and a triangle _{T 2} (i.e. twist angle of the recess 52) to theta _a.

A circumscribed circle of the shape _{T 3} and _{C 2h,} the radius of the circumscribed circle _{C 2h} and _{R 2h.} Also the largest circle that is included in contact with the inner shape _{T 3} and _{C 3h,} the radius of the circle _{C 3h} and _{R 3h.}

FIG. 4 shows a view for explaining a recess 52 ′ which is a modification of the recess. 4A corresponds to FIG. 2B, and FIG. 4B corresponds to FIG. In addition to the concave portion 52, the concave portion 52 ′ has a shape in which an arc is formed by hollowing out the inside with a circle centering on the axis. Even in such a case, as shown in FIG. 4B, each shape in the recess can be defined. At this time, the circle _C3h is a circle that forms an arc that is hollowed out.

  The relationship between each shape demonstrated above and the bearing member 30 (refer FIG. 7) is demonstrated later.

  Next, the process cartridge 3 will be described. FIG. 5 schematically shows the structure of the process cartridge 3. As can be seen from FIG. 5, the process cartridge 3 includes a photosensitive drum unit 10 (see FIG. 6), a charging roller 4, a developing roller 5, a regulating member 6, and a cleaning blade 7. When the process cartridge 3 is mounted on the apparatus main body 2 and the recording medium such as paper moves along the line indicated by V in FIG. 5, the image is transferred to the recording medium.

The process cartridge 3 is attached to and detached from the apparatus main body 2 in the following manner. Since the photosensitive drum unit 10 provided in the process cartridge 3 receives a rotational driving force from the apparatus main body 2 and rotates, the driving shaft 51 (see FIG. 2) of the apparatus main body 2 and the bearing member of the photosensitive drum unit 10 are at least operated. 30 (see FIG. 7) must be engaged. On the other hand, when the process cartridge 3 is attached to or detached from the apparatus main body 2, the engagement between the drive shaft 51 of the apparatus main body 2 and the bearing member 30 of the photosensitive drum unit 10 needs to be released (released).
Therefore, the drive shaft 51 of the apparatus main body 2 is configured to be movable in the direction along the axis, and the drive shaft 51 is detached from the bearing member 30 of the photosensitive drum unit 10 when the process cartridge 3 is attached or detached. is there. On the other hand, after the process cartridge 3 is mounted on the apparatus main body 2, the drive shaft 51 moves and engages with the bearing member 30 of the photosensitive drum unit 10.
As described above, it is preferable that the drive shaft 51 of the apparatus main body 2 and the bearing member 30 of the photosensitive drum unit 10 transmit an appropriate rotational driving force and be smoothly engaged and disengaged.
Each configuration will be described below.

  As described above, the process cartridge 3 includes the charging roller 4, the developing roller 5, the regulating member 6, the cleaning blade 7, and the photosensitive drum unit 10, each of which is as follows.

The charging roller 4 charges the photosensitive drum 11 of the photosensitive drum unit 10 by applying a voltage from the image forming apparatus main body 2. This is performed by the charging roller 4 rotating following the photosensitive drum 11 and contacting the outer peripheral surface of the photosensitive drum 11.
The developing roller 5 is a roller that supplies a developer to the photosensitive drum 11. Then, the electrostatic latent image formed on the photosensitive drum 11 is developed by the developing roller 5. The developing roller 5 contains a fixed magnet.
The regulating member 6 is a member that adjusts the amount of the developer adhering to the outer peripheral surface of the developing roller 5 and imparts triboelectric charge to the developer itself.
The cleaning blade 7 is a blade that contacts the outer peripheral surface of the photosensitive drum 11 and removes the developer remaining after the transfer by the tip.

  The photosensitive drum unit 10 includes a photosensitive drum 11 on which characters, graphics, and the like to be transferred to a recording medium are formed. FIG. 6 shows an external perspective view of the photosensitive drum unit 10. As can be seen from FIG. 6, the photosensitive drum unit 10 includes a photosensitive drum 11, a lid material 12, and an end member 20.

The photosensitive drum 11 is a member in which a photosensitive layer is coated on the outer peripheral surface of a cylindrical base. Characters, figures, and the like to be transferred to a recording medium such as paper are formed on the photosensitive layer.
The base is formed of a conductive material made of aluminum or aluminum alloy in a cylindrical shape. The type of aluminum alloy used for the substrate is not particularly limited, but is a 6000 series, 5000 series, 3000 series aluminum alloy defined by JIS standards (JIS H 4140) which is often used as a substrate of a photosensitive drum. It is preferable that
Further, the photosensitive layer formed on the outer peripheral surface of the substrate is not particularly limited, and a known one can be applied according to the purpose.
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.

  An end member 20 is attached to one end of the photosensitive drum 11 as will be described later, and a lid member 12 is disposed at the other end.

The lid member 12 is a member formed of resin, and a fitting portion that is fitted inside the cylinder of the photosensitive drum 11 and a bearing portion that is arranged so as to cover one end surface of the photosensitive drum 11 are coaxial. Are combined. The bearing portion has a disk shape that covers the end surface of the photosensitive drum 11 and includes a portion that receives the shaft. In addition, a ground plate made of a conductive material is disposed on the lid member 12, thereby electrically connecting the photosensitive drum 11 and the apparatus main body 2.
Note that although an example of the lid material is shown in this embodiment, the present invention is not limited to this, and it is also possible to apply other forms of the lid material that can be normally taken. For example, a gear for transmitting rotational force may be disposed on the lid material.
Moreover, the said electroconductive material may be provided in the edge part member 20 side mentioned later.

  The end member 20 is a member that is attached to the end of the photosensitive drum 11 opposite to the lid member 12, and includes a main body 21 and a bearing member 30. FIG. 7 shows a perspective view of the end member 20. FIG. 8 shows a front view and a side view of the end member 20. 8A is a front view of the end member 20 viewed from the direction indicated by VIIIa in FIG. 7, and FIG. 8B is a side view of the end member 20 viewed from the direction indicated by VIIIb in FIG. FIG.

  As can be seen from FIGS. 6 to 8, in this embodiment, the end member 20 is configured by integrally forming the main body 21 and the bearing member 30. The end member 20 has a main body 21 mounted on the photosensitive drum 11, and a bearing member 30 provided integrally with the main body 21 is engaged with the drive shaft 51 of the apparatus main body 2 to receive a rotational driving force. The body drum unit 10 is rotated.

  The main body 21 includes a cylindrical body 22, a contact wall 23 that contacts and locks the end surface of the photosensitive drum 11, and a fitting portion 24 that is inserted inside the photosensitive drum 11.

  The cylindrical body 22 is a bottomed cylindrical member having a bottom at one end and a contact wall 23 at the other end. From the bottom of the cylindrical body 22, the bearing member 30 is provided so as to protrude outward.

  The contact wall 23 is provided at the end of the cylindrical body 22 opposite to the side on which the bearing member 30 is provided, and is a ring (annular) shape standing on the outer peripheral surface of the cylindrical body 22. It is a member. As can be seen from FIG. 6, the contact wall 23 is disposed so as to contact the end surface of the photosensitive drum 11 with the end member 20 mounted on the photosensitive drum 11. As a result, the insertion depth of the end member 20 into the photosensitive drum 11 is restricted.

The fitting portion 24 is a cylindrical portion that protrudes to the opposite side of the contact wall 23 from the side on which the cylindrical body 22 is provided. The fitting portion 24 is inserted inside the photosensitive drum 11 and is fixed to the inner surface of the photosensitive drum 11 with an adhesive. As a result, the end member 20 is fixed to the end of the photosensitive 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.
A groove 24 a may be formed on the outer peripheral surface of the fitting portion 24. As a result, the groove 24a is filled with an adhesive, and adhesion between the end member 20 and the photosensitive drum 11 is improved by an anchor effect or the like.

  The bearing member 30 is a convex member that engages with the recess 52 provided in the drive shaft 51 of the apparatus main body 2 described above and has a function of transmitting the rotational force from the drive shaft 51 to the end member 20. Further, when the process cartridge 3 is attached to and detached from the apparatus main body 2, the bearing member 30 is configured to be detached from the concave portion 52 of the drive shaft 51. Specifically, the bearing member 30 of the present embodiment has the following shape.

  As can be seen from FIGS. 8A and 8B, the bearing member 30 is a cylindrical body provided so as to protrude in the axial direction from the bottom of the cylindrical body 22, and is orthogonal to the direction in which the axis extends. In the cross section, the outer peripheral shape is a polygon described below, and the inner peripheral shape is a circle. FIG. 9 shows an enlarged view of the outer peripheral shape of the bearing member 30 in FIG. 8A and explaining the outer peripheral shape of the bearing member 30.

As can be seen from FIG. 9, the bearing member 30 has three rotational force transmission tops 31, 32, 33, rotational force transmission sides 41, 42, 43 and adjacent rotational force transmission tops 31, 32, 33 in its outer peripheral shape. There are alignment protrusions 34, 35, and 36 that are protrusions that are arranged at portions that do not overlap the rotational force transmission sides 41, 42, and 43. As will be described in detail later, the rotational force transmission tops 31, 32, 33 and the rotational force transmission sides 41, 42, 43 are hooked on the wall surface of the recess 52 of the drive shaft 51, and are attached to the end member 20 and the photosensitive drum 11. It functions as a part for transmitting the rotational force from the drive shaft 51. On the other hand, the alignment protrusions 34, 35, 36 position the bearing member 30 so that the top portions 34 a, 35 a, 36 a are in contact with the wall surface of the recess 52 and the axis of the bearing member 30 and the axis of the recess 52 coincide. Functions as a site.
The shape of each part of the bearing member 30 that functions in this way is configured based on the matters described below.

As shown by a broken line in FIG. 9, a hexagon T _{4 including the} bearing member 30 is defined in this cross section. In this hexagon T ₄ , the apexes not adjacent to each other coincide with the rotational force transmission apexes 31, 32, 33.

Representing a diagram illustrating further the hexagonal T ₄ in FIG. 10 (hexagonal T ₄ are indicated by the bold line in FIG. 10.). In the bearing member 30, define the following shape from the hexagonal T _4.

Of the sides of the hexagonal T _4, and T ₅ the smallest triangle includes three sides not adjacent to one another. Further, among the sides constituting the hexagon T ₄ , the smallest triangle including three sides not included in the triangle T ₅ is defined as T ₆ . A circumscribed circle of the triangles T ₅ and T ₆ is C _1p, and a radius of the circumscribed circle C _1p is R _1p . That is, consider the hexagon T ₄ so that T ₅ and T ₆ have the same circumscribed circle.

The rotation angle of the triangle _{T 5} and a triangle _{T 6} and theta _p.

The circumscribed circle of the hexagon T ₄ is C _2p, and the radius of the circumscribed circle C _2p is R _2p . Further, the maximum circle included in the hexagon T ₄ is C _3p, and the radius of the circle C _3p is R _3p .

Next, assuming that a hexagonal column is formed by the hexagon T ₄ and is used as a temporary bearing member 30 ′, the engagement between the temporary bearing member 30 ′ and the recess 52 of the drive shaft 51 is considered. FIG. 11 to FIG. 13 are diagrams for explanation. FIG. 11 is a perspective view schematically showing a state in which the temporary bearing member 30 ′ is engaged with the recess 52. FIG. 12 is a diagram schematically showing a cross section along the direction in which the axis extends in a posture in which the recess 52 and the temporary bearing member 30 ′ are engaged. Accordingly, FIG. 12 shows a state in the depth direction in which the temporary bearing member 30 ′ is inserted into the recess 52. FIG. 13 is a view showing a posture in which the concave portion 52 and the temporary bearing member 30 ′ are engaged with each other on the end surface of the drive shaft 51. Also it showed a triangle T _h is a cross-section of the recess 52 in the insertion depth h by the dashed line in FIG. 13.

As can be seen from FIG. 11, after the process cartridge 3 is mounted on the apparatus main body 2, the drive shaft 51 moves in the axial direction and the temporary bearing member 30 ′ is inserted inside the recess 52. After the insertion, as shown in FIG. 13, at least three of the hexagonal outer peripheral surfaces of the temporary bearing member 30 ′ are in contact with the ridgeline of the triangle T _{1 on} the end surface of the recess 52, and the shaft Both engage with each other in a posture capable of transmitting the surrounding rotational driving force. At this time, the protrusion 53 provided in the recess 52 is inserted into the inner space of the temporary bearing member 30 ′ that is cylindrical.
When the drive shaft 51 and the temporary bearing member 30 ′ are engaged, the drive shaft 51, the temporary bearing member 30 ′, the main body 21, and the photosensitive drum 11 are coaxial.

The following shape is defined by the posture of engagement between the recess 52 and the temporary bearing member 30 ′. This form of hexagonal T ₄ is further identified by.

As can be seen from FIG. 12, the axial size of the dummy bearing member 30 'h _p, the axial size of the recess 52 (depth) and h _h. Accordingly, the insertion depth of the temporary bearing member 30 ′ into the recess 52 is set to h. In the example shown in FIG. 12, since h _p > h _h , h = h _h . On the other hand, when h _p <h _h , h = h _p . The relationship in the direction along the axis does not change in the process of changing from the temporary bearing member 30 ′ to the bearing member 30 as will be described later.

A triangle T ₁ appearing on the end face of the drive shaft 51 in the cross section of the recess 52, the twist angle of the triangle T _h is a cross-section of the recess 52 in the insertion depth h and theta _h (see FIG. 13). In the case of FIG. 12, θ _h = θ _a (see FIG. 3).

As can be seen from FIG. 13, the triangle T ₁ of the ridge line and the temporary bearing member 30 in the opening of the recess 52 'of the contact length between the L _c, temporary bearing member 30 in contact with the triangle T _1' side and triangular The angle formed by the side of T ₁ is defined as θ _m . Site of the contact length _{L c} is the rotational force transmitting sides 41, 42, 43. The rotational force transmission sides 41, 42, and 43 are portions that are caught by the wall surface of the recess 52 when the drive shaft 51 rotates and transmit the rotational drive force from the drive shaft 51 to the end member 20 and the photosensitive drum 11. is there. That is, it is a part having the same function as the above-described rotational force transmission tops 31, 32, 33. Here, in this embodiment, one end side of the rotational force transmission sides 41, 42, 43 is the rotational force transmission top portions 31, 32, 33.

  And it is preferable that each shape demonstrated above has the following relationship.

R _1p / R _1h is 0.85 or more and 1.07 or less. If this value is smaller than the range, the strength of the bearing member is weakened, and rotation transmission may not be performed properly. If the value is larger than this range, the bearing member and the recess may not be smoothly attached and detached.

R _2p -R _3h > 0 mm is preferable. Satisfying this makes it possible to transmit the rotational force between the bearing member and the recess.

When the part which forms a recessed part among drive shafts consists of nonmetallic materials, _{R2p- R3h} > 1mm is preferable. Thereby, non-metal (resin etc.) which is easy to be plastically deformed or broken can be appropriately applied.

L _c is preferably greater than 0.5 mm, more preferably greater than 1 mm, and most preferably greater than 1.5 mm. If _Lc is 0.5 mm or less, the rotational force cannot be transmitted, or even if the rotational force can be transmitted, the contact area is small, and there is a risk that large scratches or dents may occur. .

θ _m is preferably 5 ° or less. If it is larger than this, the edge (edge) of the bearing member comes into contact with the recess particularly strongly, and scratches and dents are easily formed.

It is preferable that 0.5 ≦ θ _p / θ _a ≦ 1.5.

The volume where the recess 52 and the bearing member 30 interfere with each other at a portion other than the contact portion to be considered as L _c is preferably 1 mm ³ or less. The presence or absence of such interference can be obtained by converting the concave portion and the bearing member into data using CAD or the like and combining them. That is, the volume which interferes can be calculated | required by assembling the bearing member and recessed part created on CAD, and imitating the state which both engage and transmit the rotation.

Further, in the outer peripheral shape (hexagonal T ₄ ) of the temporary bearing member 30 ′ described so far, the outer peripheral shape may be corrected in order to further improve the rotational force transmission performance and reduce the occurrence of dents. . FIGS. 14 and 15 are diagrams for explaining the correction. 14A and 14B are diagrams for explaining one correction. FIG. 14A is a diagram showing a state before correction, which is based on the same viewpoint as FIG. 13, and FIG. 14B is a diagram for explaining a concept regarding correction. From the same viewpoint as a). 15A and 15B are diagrams for explaining other corrections. FIG. 15A is a diagram showing the state before the correction, which is based on the same viewpoint as FIG. 13, and FIG. 15B is a diagram for explaining the concept regarding the correction. From the same viewpoint as a).

One correction is as follows. FIG. 14A shows an example of a scene when it is preferable to perform the one correction. That is, at this time, the rotational force can be transmitted, and the strength of the temporary bearing member 30 ′ is not problematic, but there are few contact portions between the temporary bearing member 30 ′ and the recess 52, and the rotational force transmitting sides 41, 42, since 43 L _C is small, here scratches and dents the force is concentrated is concerned. In such a case, as shown in FIG. 14B, the correction angle θ ₂ is subtracted from θ _m before correction. Thus, as can be seen from FIG. 14 (b), it is possible to increase the L _c of the rotation force transmission side 41, 42 and 43, it is possible to suppress the occurrence of scratches and dents.
On the other hand, contrary to the FIG. 14 (a), the there may be situations where theta _m becomes negative before correction. At this time, the apex indicated by B in FIG. 14A is in contact with the side wall of the recess 52, and the rotational force transmission top 31 that should be in contact with the side wall of the recess 52 is not in contact with the side wall of the recess 52. For this, a negative correction angle θ ₂ is subtracted from θ _m before correction. That is, in this case, the correction to increase the theta _m.

Such a correction angle θ ₂ is preferably applied according to the following criteria. That is, when R _1p / R _1h is 0.85 or more and 0.93 or less, θ ₂ is 1 ° or more and 10 ° or less. When R _1p / R _1h is 0.96 or more and 1.07 or less, θ ₂ is −10 ° or more and −0.1 ° or less. Here, θ ₂ is positive in the direction of increasing the volume of the temporary bearing member 30 ′, and θ ₂ is negative in the direction of decreasing the volume of the temporary bearing member 30 ′.
By correcting in this range, the rotation transmission surface of the rotational force transmitting side and the concave side of the bearing member is in contact with the linear, i.e., larger L _c of the rotation force transmission side 41, 42, 43 Therefore, scratches and dents associated with rotation transmission can be suppressed.

On the other hand, the other correction is as follows. The FIG. 15 (a), the are also shown a triangle T _h is a cross-section of the recess 52 in the insertion depth h by a broken line. In this example, like the correction of the above-mentioned θ _2, θ _m -θ ₂ is almost 0, it was possible to secure a large L _C, on the other hand, as shown in D in FIG. 15 (a), A corner portion of the temporary bearing member 30 ′ that does not transmit the rotational force is in contact (interference) with the side wall of the concave portion 52 at a portion that is an intersection of the opening side end portion and the bottom portion of the concave portion 52 in plan view. . Since this portion in the recess 52 is a portion formed by continuously twisting a triangle, it is a curved surface and interference is likely to occur.
In such a case, contact (interference) can be avoided by setting the correction angle θ ₁ and correcting the inclination angle of the interfering surface of the temporary bearing member 30 ′ as shown in FIG. can do. Here, the inclination angle means an angle formed with respect to the rotational force transmission sides 41, 42, and 43 in a hexagonal cross section that does not contribute to rotational force transmission, that is, a side that does not belong to the rotational force transmission sides 41, 42, and 43.

Such a correction angle θ ₁ is preferably applied according to the following criteria. That is, when R _1p / R _1h is 0.85 or more and 0.93 or less, θ ₁ is 0.1 ° or more and 10 ° or less. Thereby, since the corner | angular part which does not transmit rotational force among the temporary bearing members 30 'side is prevented from contacting without contacting the side wall of a recessed part, engagement and disengagement can be performed smoothly. Here, θ ₁ is positive means an angle in a direction in which a corner portion that does not transmit the rotational force before correction is away from D.

Here, the combination in which another correction (θ ₁ ) is performed according to the form generated by one correction (θ ₂ ) has been described, but the form of FIG. 15A regardless of whether or not one correction is performed. Sometimes it becomes. Accordingly, at this time, other corrections (θ ₁ ) can be performed regardless of one correction. Further, when a more appropriate form can be obtained with only one correction, there is no need to perform another correction.

  Further, the above correction may be applied in the same manner to all of the three rotational force transmission peaks 31, 32, 33 and the three rotational force transmission sides 41, 42, 43, or may be performed individually differently. Good.

So far, the provisional bearing member 30 ′ with the defined hexagon T ₄ has been described. According to this, a rotational driving force is transmitted, scratches and dents generated on the drive shaft and the bearing member are suppressed, and the apparatus main body and the photosensitive drum can be smoothly attached and detached. However, regardless of the presence or absence of the correction, in particular the rotational force transmitting sides 41, 42 and 43 becomes smaller (L _c becomes smaller.) In brought, elements to position the bearing member in the recess 52 is also reduced, both There is a risk that the axes will not fit.
Therefore, the bearing member 30 is based on the shape of the temporary bearing member 30 ′ described above, and is provided with alignment protrusions 34, 35, and 36 (see FIG. 9). Note that the shape of the temporary bearing member serving as a basis for providing the alignment protrusion does not need to be corrected, and when only the first correction is performed, only the second correction is performed. Or both of them may be performed.

The alignment protrusions 34, 35, 36 are arranged with the rotational force transmission tops 31, 32, 33 and the rotational force transmission sides 41, 42, 43 among the adjacent rotational force transmission tops 31, 32, 33. It is a protrusion provided in any part other than the part. Aligning projections 34, 35 and 36 as described above protrudes in a range enclosed in the hexagon _{T 4.} The shape of the alignment protrusions 34, 35, 36 is not particularly limited, and may be a triangle or another form in the viewpoint of FIG. In order to bring the aligning protrusions 34, 35, 36 into contact with the surface of the recess 52 with as little area as possible, the aligning protrusions 34, 35, 36 preferably have apexes 34a, 35a, 36a from the viewpoint of FIG.

When such a bearing member 30 is engaged with the recess 52 of the drive shaft 51, the following occurs. FIG. 16 shows a view from the same viewpoint as FIG. 13 in a posture in which the bearing member 30 is inserted into the recess 52. As can be seen from FIG. 16, in a posture in which the bearing member 30 is disposed inside the recess 52, the rotational force transmission tops 31, 32, 33 and the rotational force transmission sides 41, 42, 43 are cross sections at the opening end of the recess 52. caught in the triangle T ₁ is brought into a state for transmitting a rotational force. Furthermore, alignment projections 34, 35 and 36 is its tip apex 34a, 35a, 36a is, in this embodiment in contact with the approximate center of each triangle strip _{T h} is a one cross-section of the recess. Thereby, positioning of the bearing member 30 in the recessed part 52 is performed, and both axial lines can be made to correspond.

  In other words, the alignment protrusions 34, 35, and 36 are set so that the number of the alignment protrusions 34 and the protrusion amount can be adjusted so that the axis lines of the bearing member and the recess coincide with each other.

Further, there is no particular limitation on the portions other than the rotational force transmission top portions 31, 32, 33, the rotational force transmission sides 41, 42, 43, and the alignment protrusions 34, 35, 36 in the bearing member 30, but as described above. It can be a shape based on the hexagon T ₄ and its correction. In addition, from the viewpoint of avoiding interference (contact) with the concave portion 52, depressions 37, 38, and 39 may be provided on both sides of the alignment protrusions 34, 35, and 36 as in the present embodiment.

  According to the bearing member 30 described above, if all of the shapes shown in FIG. 9 are broken lines and ridge lines and valley lines are formed, the total number of ridge lines and valley lines is 10 or more, that is, as shown in FIG. The outer peripheral shape of the bearing member 30 in the cross section is formed by a polygon having 10 or more corners.

Further, the bearing member 30 does not have a so-called twisted shape in the axial direction, and there is no portion that becomes an undercut. That the undercut does not exist, that is, when the bearing member 30 is viewed in the axial direction from the base side end portion (the main body 21 side end portion) of the bearing member 30 (the back side opposite to FIG. 8A) When the bearing member 30 is viewed from above, the other parts of the bearing member 30 are invisible.
Thereby, when the bearing member 30 (end member 20) is formed, the filling of the material into the mold and the release property are improved, and the productivity is improved. Further, since the slide core and the top rotation mechanism are not required, the configuration of the mold itself can be simplified. Further, as will be described later, when the bearing member 30 is engaged with the recess 52 and when it is disengaged, the engagement / disengagement can be performed smoothly.

  The inner peripheral shape of the bearing member 30 does not necessarily have a circular cross section, and may be any shape as long as it can engage with the recess 52. In this embodiment, the bearing member 30 is a cylindrical body, but it may be a solid column.

The end member 20 is preferably formed of a crystalline resin. If it is a crystalline resin, the mold has a good flow when injection molding using a mold, so that the moldability is good, and it is released from the mold by crystallizing and solidifying without cooling to the glass transition point. can do. Therefore, productivity can be greatly improved. In addition, the crystalline resin is excellent in heat resistance, solvent resistance, oil resistance, grease resistance, friction wear resistance and slidability, and also in the end member from the viewpoint of rigidity and hardness. It is preferable as a material to be applied.
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 a polyacetal resin from the viewpoint of moldability.
Further, from the viewpoint of increasing the strength, glass fiber, carbon fiber or the like may be filled.

  Further, a conductive plate (ground plate) is provided on the end member side provided with the bearing member 30 and is brought into contact with an electrode provided on the drive shaft 51 side of the apparatus main body 2 so that the photosensitive drum 11 is conductive. Is also possible. In that case, forms, such as a method of forming the bearing member 30 itself with a conductive material or exposing a conductive plate on the inner periphery of the bearing member 30, can be applied.

Next, operations and operations of the image forming apparatus 1 described above will be described.
The process cartridge 3 is attached to the apparatus main body 2 by inserting the process cartridge 3 into the apparatus main body 2 along a predetermined guide as shown in FIG. At this time, the drive shaft 51 of the apparatus main body 2 is in a position retracted from the orbit of movement of the process cartridge 3.
After the process cartridge 3 is placed in a predetermined position of the apparatus main body 2, the drive shaft 51 moves to the process cartridge 3 as shown in FIG. 10 in conjunction with the operation of closing the lid of the apparatus main body 2 or by another operation. The bearing member 30 is inserted into the recess 52 of the drive shaft 51 as shown in FIG. As a result, the rotational driving force from the apparatus main body 2 is transmitted to the bearing member 30, the end member 20, and the photosensitive drum 11, and can rotate around the axis line in synchronization. Further, the rotational driving force from the apparatus main body 2 is transmitted directly or via other members to other constituent members (for example, the charging means 4) provided in the process cartridge 3, and these can also rotate.

In this manner, the image forming apparatus is operated in a posture in which the process cartridge 3 is mounted and the photosensitive drum 11 and the like can be rotated. When a desired character or figure is represented on the recording medium, a rotational driving force is applied from the apparatus main body 2, the photosensitive drum unit 10 is rotated, and the photosensitive drum 11 is charged by the charging roller 4.
While the photosensitive drum unit 10 is rotating, laser light corresponding to image information is irradiated to the photosensitive drum 11 using various optical members (not shown), and an electrostatic latent image based on the image information is obtained. This latent image is developed by the developing roller 5.
On the other hand, a recording medium such as paper is set in another part of the apparatus main body 2 and is conveyed to a transfer position by a feed roller, a conveyance roller, etc. provided in the apparatus main body 2 and moves along a line V in FIG. . A transfer unit 1a is disposed at the transfer position. A voltage is applied to the transfer unit 1a as the recording medium passes, and an image is transferred from the photosensitive drum 11 to the recording medium. Thereafter, the image is fixed to the recording medium by applying heat and pressure to the recording medium. Then, the recording medium on which the image is formed is discharged from the apparatus main body 2 by a discharge roll or the like.
In the photosensitive drum 11, in preparation for the next image, the cleaning blade 7 comes into contact with the outer peripheral surface of the photosensitive drum 11 and the developer remaining after the transfer is removed by the tip of the cleaning blade 7. The developer scraped off by the cleaning blade 7 is discharged in a known manner.

There are many opportunities to attach and detach the process cartridge also from the operation and operation of the image forming apparatus, and when the image forming apparatus 1 is operated, the photosensitive drum 11 is subjected to heavy load due to repeated rotation and stoppage, and charging, heating, etc. It can be seen that there is a severe condition that there is. According to the present invention, with the above-described form, in addition to the basic function of appropriately transmitting the rotational driving force, it is possible to ensure sufficient rotational accuracy because the axis is located. Further, since the bearing member 30 is not twisted and there is no undercut portion, the recess 52 and the bearing member 30 can be easily attached and detached.
Furthermore, from the viewpoint of production of the bearing member 30, since it is not a twisted shape and there is no undercut part, it is possible to improve the filling of the material into the mold and the releasability, thereby improving the productivity of the end member. It is done. Further, since the slide core and the top rotation mechanism are not required, the mold configuration can be simplified.

  Although one example of the bearing member has been described above, it is sufficient that at least one alignment protrusion is provided, and various forms can be applied to the sectional shape of the bearing member. Several forms are illustrated below. Each figure is a figure from the same viewpoint as FIG. 16, and functions in the same manner as the bearing member 30.

  FIG. 17 shows an example of the bearing member 130 in which the depressions 37, 38, and 39 are not provided in the bearing member 30 described above.

  FIG. 18 is an example in which only one alignment protrusion is provided. FIG. 18A shows a bearing member 230 in which only the alignment protrusion 34 is provided with respect to the bearing member 30. FIG. 18B shows a bearing member 330 provided with a hollow that is curved with respect to a side where no alignment protrusion is provided. According to this, in the said hollow, it is spaced apart greatly from the wall surface of the recessed part 52, and an unnecessary contact can be prevented more reliably.

  FIG. 19 is an example in which two alignment protrusions are provided, and is a bearing member 430 in which two alignment protrusions 34 and 35 are provided on the bearing member 30.

FIG. 20 shows a bearing member 530 having three alignment protrusions 534, 535, and 536 and its apexes 534a, 534a, and 536a as in the bearing member 30. The alignment protrusions 534, 535, and 536 are formed over the entirety between the ends of the rotational force transmission sides 41, 42, and 43 and the rotational force transmission vertices 31, 32, and 33. Further, in this example, the vertices 534 a, 534 a, and 536 a are in contact with the recess 52 at a position largely deviated from the center of the side of the recess 52, that is, the twisted inclined surface of the recess 52.
In this example, three alignment protrusions 534, 535, and 536 are provided, but any one or two may be provided.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming apparatus main body 3 Process cartridge 10 Photoconductor drum unit 11 Photoconductor drum 20 End member 30 Bearing member 51 Drive shaft 52 Recessed part

Claims (10)

An end member disposed at the end of the photosensitive drum unit that is detachably mounted to the main body of the image forming apparatus provided with a drive shaft having a recess having a substantially triangular cross-sectional shape and a twisted hole in the axial direction. Because
A convex bearing member that can be engaged with and detached from the concave portion is provided,
The bearing member has no undercut portion in the direction along the axis of the outer peripheral surface, and the outer peripheral shape is polygonal in the cross section orthogonal to the direction in which the axis extends.
The polygon is
At least three rotational force transmission tops that are in contact with the inner surface of the concave portion and are caught by the concave portion when the drive shaft rotates and transmit rotational force;
A rotational force transmission side that is a side at least partially in contact with the recess;
An end member comprising: at least one aligning protrusion which is disposed at a portion other than the rotational force transmitting side between the adjacent rotational force transmitting tops, and whose tip is a protrusion contacting the concave portion.   2. The end member according to claim 1, wherein the aligning protrusion is provided at a position where the tip of the aligning protrusion contacts a center of the triangular side of the recess.   2. The end member according to claim 1, wherein the aligning protrusion is provided at a position where the tip of the aligning protrusion is in contact with a hypotenuse of a wall surface that is the twisted triangle of the recess.   The end member according to any one of claims 1 to 3, wherein the polygon is a polygon having 10 or more corners. In the cross-section of the bearing member, a hexagonal shape in which each of the three rotational force transmission tops is a vertex that is not adjacent to each other, and the smallest triangular shape including three sides that are not adjacent to each other among the sides constituting the hexagonal shape. When the radius of the circumscribed circle is R _1p and the radius of the circumscribed circle of the smallest triangle including the substantially cross-sectional shape of the recess is R _1h ,
0.85 ≦ R _1p / R _1h ≦ 1.07
The end member according to any one of claims 1 to 4, wherein The hexagonal cross-sectional shape has a corrected shape,
The corrected shape is a shape in which the inclination angle is changed from the pre-correction to the post-correction inclination angle θ _{1 in} one set that does not contribute to rotational force transmission among the three non-adjacent sides of the hexagonal cross section,
6. The end member according to claim 5, wherein the correction angle θ ₁ is such that θ ₁ is 0.1 ° or more and 10 ° or less when the R _1p / R _1h is 0.85 or more and 0.93 or less. In a posture in which the concave portion and the bearing member are engaged and can transmit a rotational force, a contact length between the ridge line in the opening of the concave portion and the bearing member is L _c , When the angle formed by the ridge line of the concave portion is θ _m , and the correction angle to be changed from the hexagon before the change to change the θ _m is θ ₂ ,
The end member according to claim 5 or 6, wherein θ ₂ is 0.1 ° or more and 10 ° or less when R _1p / R _1h is 0.85 or more and 0.93 or less. In a posture in which the concave portion and the bearing member are engaged and can transmit a rotational force, a contact length between the ridge line in the opening of the concave portion and the bearing member is L _c , When the angle formed by the ridge line of the concave portion is θ _m , and the correction angle to be changed from the hexagon before the change to change the θ _m is θ ₂ ,
The end member according to claim 5 or 6, wherein θ ₂ is -10 ° or more and -0.1 ° or less when R _1p / R _1h is 0.96 or more and 1.07 or less.   A photosensitive drum unit comprising: a cylindrical photosensitive drum; and an end member according to claim 1 attached to at least one end of the photosensitive drum. A photosensitive drum unit according to claim 9,
A charging roll for charging the photosensitive drum of the photosensitive drum unit;
And a developing roll for developing an electrostatic latent image on the photosensitive drum.

Images