JP2007219266A - Cartridge, and electrophotographic image forming device equipped with the cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge having superior usability at low cost, using a longitudinal cartridge insertion method with a rotational coupling mechanism, whereby a rotation passive part on the cartridge side is connected to a drum-driving gear on the image forming device side, when the cartridge is inserted. <P>SOLUTION: The process cartridge 7 is inserted into cartridge support parts 112, provided to a front side plate 110 and a back side plate 111 of the body of the device along the rotational axis line of the photoreceptor drum 1. The rotation passive part 15 protrudes from the edge of the drum shaft 14, and an alignment convex part (first alignment part) 16 further protrudes from the rotation passive part. When the cartridge is inserted, the cartridge is fitted to the concave rotary drive part 123a and the alignment concave part (second alignment part) 123b provided to the drum drive gear 123 on the device body side, and the connection is made by the end face coupling method. Positioning is made by a positioning rod 18, which is thicker and longer than the cartridge support part 112. The user can attach or detach the process cartridge 7, and carry out positioning with natural and easy usability, without being especially aware of this. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus (hereinafter simply referred to as an “image forming apparatus”) such as a copying machine, an electrophotographic printer such as a laser beam printer or an LED printer, a facsimile machine, and a multifunction machine. The present invention relates to a cartridge used.

  2. Description of the Related Art Conventionally, an image forming apparatus that executes an electrophotographic image forming process to form an image on a sheet such as recording paper is known. In this image forming apparatus, an electrostatic image formed on an electrophotographic photosensitive drum (hereinafter simply referred to as “photosensitive drum”) or the like is developed with a developer (toner) attached by a developing means, and transferred onto a sheet. The method is used. In this case, the photosensitive drum as the electrostatic latent image carrier and the process means acting on the photosensitive drum are integrated into a cartridge so that the process cartridge can be detachably attached to the image forming apparatus main body. There is something that was made The process means means at least one of a charging means, a developing means, and a cleaning means. By making the photosensitive drum and the process means into such a cartridge, the user himself can perform maintenance of the apparatus that has been dependent on the serviceman, and the usability has been greatly improved. Yes.

  An inline type color image forming apparatus in which a plurality of such process cartridges are arranged in a line is well known. In the case of this inline type color image forming apparatus, if the parallelism between the photosensitive drum and the scanner unit (exposure means) that irradiates the latent image pattern on the surface of the photosensitive drum with laser light is lost, the printed image will be misregulated. Arise. In order to prevent this, it is required to position the photosensitive drum and the plurality of scanner units in parallel with high accuracy. The parallel state of the photosensitive drum and the scanner unit means that the rotation axis of the photosensitive drum and the plane formed by the irradiation light from the scanner unit are parallel to each other, and the optical path length of the irradiation light on the left and right of the photosensitive drum. Is equivalent. By positioning the photosensitive drum and the scanner unit in this way, it is possible to form an image without distortion. On the other hand, it is necessary to consider not only the relative positions of the photosensitive drum and the scanner unit but also the parallelism between the image forming processes. Since a color image is formed by superimposing a plurality of color toner images, even if image formation that does not cause distortion is executed in each image forming process, color misregistration occurs if parallelism is not ensured. It is.

  By the way, there are the following two cartridge attachment / detachment methods when classified from the direction in which the process cartridge is incorporated into and removed from the image forming apparatus main body.

  One is a case where the process cartridge is attached to and detached from the main body of the image forming apparatus from a direction orthogonal to the rotational axis of the photosensitive drum. Hereinafter, this is referred to as a “cartridge lateral insertion method” for convenience of explanation. One is a case where the process cartridge is attached to and detached from the main body of the image forming apparatus from the longitudinal direction of the drum along the rotational axis of the photosensitive drum.

  The former image forming apparatus using the cartridge horizontal insertion method has been previously proposed by the present applicant (see, for example, Patent Document 1). The image forming apparatus in this case has an opening between the left and right side plate frames of the image forming apparatus main body. The photosensitive drum faces the opening from the longitudinal direction, and the drum rotation axis is moved in parallel toward the opening so that the process cartridge is inserted horizontally. The left and right side plate frames receive and support both ends of the drum shaft of the photosensitive drum so as to be rotatable, and also support both ends of the scanner unit. In the left and right side plate frames, the drum shaft bearing and the support unit of the scanner unit are respectively pressed by elastic members and positioned so as not to be loose.

JP 2001-242671 A

  However, the image forming apparatus disclosed in Patent Document 1 has the following problems.

  That is, when the end face coupling fitting method is adopted and the process cartridge is attached to and detached from the image forming apparatus main body by the cartridge lateral insertion method, the drum driving gear needs to be released from the cartridge attaching / detaching track once. Then, it is necessary to return the drum drive gear in the retracted position to the fixed position when the process cartridge is inserted to the fixed position. Patent Document 1 discloses a configuration in which the drum drive gear is retracted in conjunction with the retracting operation of the transfer belt. However, a complicated mechanism for such a retreat operation may be required. In addition, there is a problem that the number of parts increases.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the degree of design freedom of a configuration for rotatably supporting an electrophotographic photosensitive drum in a configuration in which a cartridge is mounted on an electrophotographic image forming apparatus main body. Another object of the present invention is to reduce the cost of the structure for rotatably supporting the electrophotographic photosensitive drum.

A typical configuration of the present invention for achieving the above object is as follows.
In the cartridge that can be mounted on the electrophotographic image forming apparatus main body,
A frame forming a cartridge frame;
An electrophotographic photosensitive drum provided rotatably on the frame and having a rotation axis parallel to a mounting direction in which the cartridge is mounted on the apparatus main body;
A bearing held by the frame and rotatably supporting a tip portion of the electrophotographic photosensitive drum in the mounting direction of the cartridge;
In the mounting direction, it is a rotational passive portion provided on the tip side of the bearing and coaxially with the rotation axis so as to protrude from the tip portion, and in a state where the cartridge is mounted on the apparatus body, A rotary passive unit that receives rotational power to rotate the electrophotographic photosensitive drum by engaging with a rotation driving unit provided in the apparatus main body;
A first centering portion provided on the same axis as the rotation axis so as to protrude from the rotation passive portion on the tip side of the rotation passive portion in the mounting direction, and the cartridge is mounted to the apparatus main body. A first alignment unit that engages with a second alignment unit provided in the main body of the electrophotographic image forming apparatus to align the rotation passive unit and the rotation axis of the rotation drive unit,
A member to be positioned provided in contact with the outer periphery of the bearing, and is guided by sliding with a positioning portion provided in the electrophotographic image forming apparatus body when the cartridge is mounted in the apparatus body. And a positioned member that is positioned by the positioning portion in a state where the cartridge is mounted on the apparatus main body.

  According to the present invention, in the configuration in which the cartridge is mounted on the electrophotographic image forming apparatus main body, the degree of freedom in designing the support member that rotatably supports the electrophotographic photosensitive drum can be improved. Further, according to the present invention, the support member that rotatably supports the electrophotographic photosensitive drum can be reduced in cost.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a process cartridge and an image forming apparatus according to the invention will be described in detail with reference to the drawings.

(Image forming device)
As shown in FIG. 1, the apparatus main body 100 of the image forming apparatus to which the process cartridge 7 of the present embodiment is detachably mounted is provided with four cartridge mounting portions 101 arranged in parallel in the horizontal direction. Each process cartridge 7 mounted on each cartridge mounting unit 101 has one photosensitive drum 1 and corresponds to, for example, each color of yellow (Y), magenta (M), cyan (C), and black (K). Thus, a toner image is formed. The photosensitive drum 1 receives rotational driving from a drum driving gear (see reference numeral 123 in FIG. 7) on the apparatus main body 100 side and rotates in the clockwise direction indicated by an arrow in the drawing. Around the photosensitive drum 1, the following devices constituting process means and the like are sequentially arranged along the rotation direction.

  An exposure unit that has a charging roller 2 that uniformly charges the surface of the photosensitive drum 1 by applying a charging bias voltage, and irradiates a laser beam based on image information to form an electrostatic latent image on the photosensitive drum 1. As a scanner unit 102. The image forming apparatus further includes a developing unit 4 that develops the electrostatic latent image using toner that is a developer. Further, a cleaning belt 103 is provided that circulates and moves in contact with the photosensitive drum 1 to electrostatically transfer the toner image on the photosensitive drum 1, and removes toner remaining on the surface of the photosensitive drum 1 after transfer. Means 6 are arranged. Around the photosensitive drum 1, a charging roller 2, a developing unit 4, and a cleaning unit 6 are integrated together to form a process cartridge 7. A primary transfer roller 104 is disposed at a position facing the photosensitive drum 1 across the transfer belt 103, and presses the transfer belt 103 toward the photosensitive drum 1. The transfer belt 103 is also opposed to and in contact with the secondary transfer roller 105 at the right end portion in the drawing, and the conveyance path of the sheet S as a recording medium is between the transfer belt 103 and the contact portion of the secondary transfer roller 105. Configured to pass through. The toner image on the transfer belt 103 is transferred onto the sheet S at this contact portion.

  The image forming operation is performed as follows.

  The process cartridges 7 corresponding to the colors Y, M, C, and K are sequentially driven in accordance with the timing of image formation, so that the photosensitive drum 1 starts rotating, and the scanner unit 102 is sequentially driven accordingly. When the photosensitive drum 1 rotates, the charging roller 2 uniformly applies a charging bias voltage to the surface of the photosensitive drum 1 to apply a charge. The scanner unit 102 exposes the surface of the photosensitive drum 1 according to an image signal, and forms an electrostatic latent image on the photosensitive drum 1. The developing roller 5 provided in the developing unit 4 develops the electrostatic latent image with toner.

  The toner images on the photosensitive drums 1 are sequentially transferred onto the transfer belt 103 by an electric field formed between the photosensitive drums 1 and the primary transfer roller 104. The transfer belt 103 to which the toner images of four colors Y, M, C, and K are transferred transfers the toner image to the sheet S interposed therebetween by an electric field formed between the secondary transfer roller 105 and the transfer belt 103. . Thereafter, the sheet S is carried into the fixing unit 106, the toner image is thermally fixed by the fixing unit 106, and then discharged from the discharge unit 107 to the outside of the apparatus main body 100.

(Process cartridge)
2 to 4 show the process cartridge 7 alone. 2 is attached to and detached from the apparatus main body 100 from the longitudinal direction of the cartridge indicated by the arrow in FIG. As shown in FIG. 3, the photosensitive drum 1 is disposed in a frame 13 forming a cartridge frame with the rotation axis set in the cartridge longitudinal direction. It is configured as a “cartridge longitudinal insertion method” in which the process cartridge 7 is inserted into the apparatus main body 100 from the longitudinal direction along the rotation axis of the photosensitive drum 1.

  The photosensitive drum 1 has a drum shaft 14 extending on the rotation axis from both ends, and bearings 8 that rotatably support both ends of the drum shaft 14 are fixedly held at both ends of the frame 13. A ball bearing structure is used for the bearing 14, but other bearings such as a sintered bearing and a resin bearing are also possible. In the case of a ball bearing, there is usually a standard in which the outer diameter and width are determined by the inner diameter, and by using the standard product, it can be expected that the component cost of the bearing 8 can be suppressed by mass production. The drum shaft 14 is formed of a metal having a sufficient rigidity so that the photosensitive drum 1 rotates stably without uneven rotation.

  In the front end drum shaft 14 of the front process cartridge 7 in the cartridge insertion direction, a rotary passive portion 15 that receives rotational power at the front end of the shaft portion is formed in a substantially triangular shape and is integrally provided. As shown in each figure after FIG. 7, a drum drive gear (drum drive member) 123 is provided on a terminal unit that outputs a motor at a required rotation speed (rpm) through a reduction device or the like on the apparatus main body 100 side. Yes. A concave flange-shaped rotation driving portion 123a is provided so as to protrude to the front side facing the photosensitive drum 1 on the same axis as the drum driving gear 123.

  When the cartridge is inserted, the rotation passive portion 15 of the process cartridge 7 is engaged with the rotation drive portion 123a of the drum drive gear 123 on the apparatus main body 100 side, whereby mechanical connection by end face coupling is performed. The drum drive gear 123 is gear-coupled to the motor of the rotational power source, and transmits the rotation moderately decelerated from the motor to the photosensitive drum 1 of the process cartridge 7. Further, the drum drive gear 123 can be retracted in the gear axis direction when the rotation drive unit 123a is out of phase with the rotation passive unit 15 when the cartridge is inserted. That is, after the cartridge is inserted, the spring member 125 always urges the cartridge in the direction opposite to the cartridge insertion direction so that the coupling is performed when the coupling phases are matched in the first rotation.

  The spring member 125 has a function of absorbing and absorbing the engagement force due to the insertion of the process cartridge 7 by the drum drive gear 123 retreating by an automatic adjustment action at the time of phase shift. Although it is called backward, it is a one-cushion with a small distance, and has a different purpose and function from the conventional retracting mechanism, and does not cost. Further, the drum drive gear 123 operates like a kickback against the spring member 125. As a result, even if the user is not particularly conscious to insert the process cartridge 7 straightly, the drum drive gear 123 is automatically aligned as described below by the kickback operation of the drum drive gear 123 even if it is inserted slightly obliquely. Therefore, it is very convenient for the user.

  In FIG. 7, the drum drive gear 123 is supported roughly within the apparatus main body 100 with a slight backlash in the gear radial direction in an unloaded state where the process cartridge 7 is not inserted. Further, the drum drive gear 123 has a hole-shaped aligning recess (second aligning portion) 123b formed in a step shape inside the rotation driving portion 123a on the rotation axis. Corresponding to the alignment recess 123b, the drum shaft 14 of the photosensitive drum 1 is provided with a rod-shaped alignment protrusion (first alignment portion) 16 that is further protruded from the rotary passive portion 15 and is step-formed. Yes. That is, when the cartridge is inserted, the alignment protrusion 16 on the drum shaft side engages with the alignment recess 123b on the apparatus main body side, so that the rotation axes of both the photosensitive drum 1 and the drum drive gear 123 automatically coincide. Automatic alignment. This automatic alignment makes it possible to suppress angular velocity fluctuations in one rotation cycle of the photosensitive drum 1 and is effective in preventing color misregistration.

(Main structure of cartridge vertical insertion system)
As shown in FIG. 3, in the cartridge frame 13, a cylindrical rod (positioned member) 18 is held in contact with the outer periphery of the bearing 8 of the drum shaft 15. The rod 18 can automatically position the photosensitive drum 1 at a predetermined position of the apparatus main body 100 when the process cartridge 7 is attached to and detached from the apparatus main body 100 from the longitudinal direction, that is, along the rotation axis of the photosensitive drum 1. It is a member for making it.

  In FIG. 3 and FIG. 4 showing a cross section from the arrow AA line in this figure, the rod 18 is longer than the width of the bearing 8 and protrudes to the front side in the cartridge insertion direction, and is perpendicular to the rotation center of the bearing 8. On the other hand, the two bearings 8 are provided so as to be distributed at equal angular positions on the left and right. These rods 18 are slightly allowed to play in the radial direction of the bearing 8 with respect to the frame 13 of the cartridge frame body, but the dimensional tolerance in the circumferential direction of the bearing 8 is strictly regulated by high-precision machining. ing. However, the cross-sectional shape of the rod 18 is a circular member that can be easily processed with the required outer diameter accuracy, but it is not necessarily limited to a circular member. Therefore, the two rods 18 are in contact with the bearing 8 on one side of the outer peripheral surface of the rod at the stage of inserting the cartridge into the apparatus main body 100 and on both sides of the V-shaped cartridge support portion (positioning recess) 112 on the other side. It is supported in contact with the inclined surface.

  As described above, the photosensitive drum 1 of the process cartridge 7 is supported by the cartridge support 112 of the apparatus main body 100 by the two bearings 8 on the front and rear sides of the photosensitive drum 1 through the bearings 8 in the longitudinal direction. The In this supported state, the bearing 8 and the rod 18 are pressed against the cartridge support 112 by pressing means or urging means (not shown) provided in the apparatus main body 100, and the photosensitive drum 1 is attached to the V-shape of the cartridge support 112. It is stabilized by pressing against the inclined surface.

  The cartridge support portion 112 is composed of two parallel side plates 110 and 111 on the front side and the rear side in the cartridge insertion direction, and the openings 118 and 119 formed in the front side plate 110 and the back side plate 111 are formed. It is the same shape formed in V shape in the lower part. The openings 118 and 119 are arranged such that the inclined end surfaces of the V-shape are parallel to each other with high accuracy. Further, the front side plate 110 and the back side plate 111 are provided for each of the process cartridges 7 corresponding to the four colors, and the scanner base 124 is also positioned and supported (see FIG. 1).

  A scanner unit 102 as a plurality of exposure means is positioned with high accuracy on the scanner table 124, and all the process cartridges 7 and the scanner table 124 are positioned with a pair of components. Therefore, the positional accuracy between the process cartridge 7 and the scanner base 124 can be kept within the range of the processing accuracy error of a single component. Further, as shown in FIG. 5, the shape of the support portion of the scanner base 124 is the same for the front side plate 110 and the back side plate 111 as in the cartridge support portion 112. In the present embodiment, the front side plate 110 and the back side plate 111 are simultaneously stacked and punched so that there is no difference in shape between the front side and the back side of the cartridge support portion 112 and the scanner support portion.

  Further, a rotation-preventing hole 19 is provided through the side surface of the frame 13 of the rear cartridge frame in the cartridge insertion direction, and engages with a rotation-preventing boss 120 shown in FIG. Thus, the rotational direction of the insertion back side drum shaft 14 is regulated. Similarly, the rotation direction of the drum shaft 14 on the front side of the insertion is made by engaging the rotation prevention boss 20 provided on the upper surface of the end portion of the frame 13 with the rotation prevention hole 121 provided on the apparatus main body 100 also on the front side of the insertion. To regulate. As a result, the slight rotational behavior at the front and rear ends of the process cartridge 7 in the insertion longitudinal direction is completely stopped.

  By adopting the positioning structure as described above, deviation and parallelism of the positional relationship between the scanner unit 102, the photosensitive drum 1, and the photosensitive drums 1 are minimized. As a result, color shift can be suppressed.

(Cartridge loading operation)
As shown in FIG. 6, the process cartridges 7 corresponding to the respective colors Y, M, C, and K are inserted into the apparatus main body 100 from this longitudinal direction, that is, along the photosensitive drum rotation axis, and loaded. When loading, the opening / closing cover 108 provided in front of the apparatus main body 100 is opened to expose the four cartridge mounting portions 101 arranged side by side. Each cartridge mounting portion 101 is provided with a guide rib 109 and a guide pin 114 for smoothly guiding the insertion of the process cartridge 7. Guided projections 9 and guided grooves 10 that are engaged with the guide ribs 109 and the guide pins 114 are provided in each process cartridge 7, and both are engaged with each other and slid by sliding to the apparatus main body 100. It can be loaded smoothly.

  7 to 9 show the operation when the cartridge is inserted. The user places the guided protrusion 9 on the guide rib 109 and then loads the process cartridge 7 in the longitudinal direction and starts loading. In the insertion start position shown in FIG. 7, the process cartridge 7 is guided at a position higher than the loading completion position. It is guided so as to fall obliquely after being inserted to some extent horizontally in the longitudinal direction. As shown in FIG. 8, the outer peripheral surface of the rod 18 contacts the cartridge support portion 112 while falling obliquely. The subsequent guide of the cartridge is transferred from the guide rib 109 and the guide pin 114 to the cartridge support portion 112. From this contact, the process cartridge 7 is inserted horizontally in the longitudinal direction while the rod 18 slides at the cartridge support portion 112. Then, when the longitudinal contact surface 21 contacts the inner surface of the cartridge mounting portion 112, the loading is completed as shown in FIG. At that time, the first alignment portion 16 that first protrudes from the tip of the drum shaft side rotation passive portion 15 in the initial stage is fitted with the second alignment portion 123b that passes through the axis of the drum drive gear 123, The rotation axis of the photosensitive drum 1 is aligned with the rotation axis of the drum driving gear 123 and is automatically aligned. Subsequently, the rotation passive portion 15 of the drum shaft 14 is coupled to the rotation drive portion 123a of the drum drive gear 123 by coupling with an end face, and mechanical connection is performed.

  At the same time, the photosensitive drum 1 is positioned and supported by the two rods 18 in the front and rear bearings 8 in contact with the front and rear cartridge support portions 112 on the apparatus main body 100 side.

  It should be noted that the rear end drum shaft is used to buffer an impact when the first centering portion 16 at the foremost portion of the drum shaft 14 is first engaged with the second centering portion 123b of the drum drive gear 123 when the cartridge is inserted. A buffer spring 17 can be provided on 14.

  As described above, in this embodiment, if the user inserts the process cartridge 7 into the apparatus main body 100 without particular care, the mechanical coupling that is positioned with high accuracy and receives rotation is completed, so that the usability is very good. It will be something.

As shown in FIG. 9, the convex first alignment portion 16 provided on the drum shaft 14 side and the concave second alignment portion 123b provided on the drum drive gear 123 side are fitted at the large diameter portion. Both the length B dimension and the fitting length C dimension at the small diameter portion can be set to about several millimeters, for example. In order to accurately engage the recesses and protrusions in the middle of the cartridge insertion, it is necessary to move at least an engagement length of several millimeters horizontally. When the cartridge is inserted, the distance D from the contact of the rod 18 with the cartridge support 112 to the loading completion position after being guided by the guide rib 109 and the guide pin 114 is set appropriately. The length L of the rod 18 can be set to several tens of millimeters. Now, if the length required for mating is B + α,
B + α <D <L (1)
The following relational expression (1) holds.

  By doing so, in the cartridge loading trajectory, the distance from the near side of the loading position to the loading position can be moved horizontally at least longer than the concave and convex engagement length while maintaining the height of the loading position. It becomes possible. As a result, the first aligning portion 16 can be engaged with the second aligning portion 123b.

  In addition, although embodiment of this invention was described as mentioned above, in the range which does not deviate from the main point of this invention, other embodiment, an application example, a modification, and those combinations are also possible.

  Further, according to the present embodiment, in the longitudinal direction of the cartridge 7, at least a part of the rod 18 and at least a part of the rotary passive part 15 can be arranged to overlap each other. Therefore, the process cartridge 7 can be made compact by reducing the length in the longitudinal direction. In addition, since the drum drive gear 123 on the apparatus main body 100 side can be arranged close to the cartridge side, it is effective for suppressing an increase in the size of the apparatus main body 100.

  Further, according to the present embodiment, by using the rod 18, restrictions on the longitudinal width and the outer diameter due to the standard of the bearing can be easily eliminated. That is, the bearing has dimensions such as a longitudinal width and an outer diameter determined according to the standard. Therefore, the cost increases when using a non-standard bearing. However, according to the present embodiment, by using the rod 18, the degree of freedom in designing the bearing configuration can be improved while using a standard bearing.

  In addition, a mechanism for separating the primary transfer roller 104 from the photosensitive drum 1 can be provided in conjunction with the operation of opening the front cover 108 of the apparatus main body 100 with respect to the position of the transfer belt 103 when the process cartridge 7 is attached or detached. The separation mechanism is operated when the process cartridge 7 is attached / detached, and is retracted in a state where a certain gap or more can always be secured between the transfer belt 103 and the process cartridge 7. As a result, when the rod 18 comes into contact with the cartridge support portion 112, damage to both of the transfer belt 103 and the photosensitive drum 1 due to friction between the transfer belt 103 and the photosensitive drum 1 is prevented until the rod 18 is moved horizontally and reaches the mounting position thereafter. it can.

である。 In this embodiment, the bearing 8 is a ball bearing having an inner diameter of φ8 mm and an outer diameter of φ22 mm. The positioned member 18 is a φ5 mm metal pin. The photosensitive drum 1 has an outer diameter of 30 mm. The amount of protrusion Δ of the bearing 8 with respect to the outer diameter of the photosensitive drum 1 is

It is.

となり、逆に軸受は４ｍｍ引っ込んだ位置にある。このような構成の場合、カートリッジ7の挿入開始位置の高さは、本実施例の構成と比較して、Δ−Δ‘＝５ｍｍ余計に高くする必要がある。なぜなら、手前側カートリッジ支持部を感光体ドラム１が乗り越える必要があるからである。したがって、カートリッジ７を装着した状態では、カートリッジ上部の高さ方向５ｍｍ分の空間がデッドスペースとなってしまう。上記５ｍｍ分の空間を現像ユニット４のトナー収容部の容積に換算すると、約2800枚分のトナー収容室に相当する。つまり、本実施例にすることによって、スペース効率が良く、コンパクトな画像形成装置を実現できる。 If the rod 18 is not provided and the configuration in which the outer diameter of the bearing 8 abuts against the cartridge support 112 is applied to the present embodiment, consider. In this case, the amount of protrusion Δ ′ of the bearing relative to the outer diameter of the photosensitive drum 1 is

On the contrary, the bearing is in a position retracted by 4 mm. In the case of such a configuration, it is necessary to make the height of the insertion start position of the cartridge 7 extra high by Δ−Δ ′ = 5 mm as compared with the configuration of the present embodiment. This is because it is necessary for the photosensitive drum 1 to get over the front cartridge support portion. Therefore, in a state where the cartridge 7 is mounted, a space of 5 mm in the height direction above the cartridge becomes a dead space. When the space of 5 mm is converted into the volume of the toner storage portion of the developing unit 4, it corresponds to a toner storage chamber of about 2800 sheets. That is, by adopting the present embodiment, a space-efficient and compact image forming apparatus can be realized.

1 is an overall configuration diagram showing a process cartridge according to an embodiment of the present invention and a color electrophotographic image forming apparatus equipped with the process cartridge. FIG. The perspective view which shows the process cartridge by the cartridge vertical insertion system of this embodiment single-piece | unit. Side surface sectional drawing of the process cartridge. The front longitudinal cross-sectional view from the arrow AA line in FIG. FIG. 6 is a perspective view showing the engagement with the image forming apparatus main body showing a cartridge insertion state. The perspective view which shows the initial state of cartridge insertion. FIG. 5 is a side cross-sectional view illustrating a process in which a process cartridge is inserted while being guided by a guide portion. FIG. 4 is a side cross-sectional view illustrating an initial alignment process in which a process cartridge is inserted while being guided by a cartridge support portion. FIG. 6 is a side cross-sectional view showing a state where alignment and positioning are performed in a process cartridge loaded state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 7 Process cartridge 8 Bearing 13 Cartridge frame 14 Drum shaft 15 Rotation passive part 16 Alignment convex part (1st alignment part)
17 Buffer spring 18 Positioning rod (positioned member)
DESCRIPTION OF SYMBOLS 100 Image forming apparatus main body 101 Cartridge mounting part 112 Cartridge support part 123 Drum drive gear (drum drive member)
123a Rotation drive part 123b Alignment recess (second alignment part)
125 Spring member

Claims (9)

In the cartridge that can be mounted on the electrophotographic image forming apparatus main body,
A frame forming a cartridge frame;
An electrophotographic photosensitive drum provided rotatably on the frame and having a rotation axis parallel to a mounting direction in which the cartridge is mounted on the apparatus main body;
A bearing held by the frame and rotatably supporting a tip portion of the electrophotographic photosensitive drum in the mounting direction of the cartridge;
In the mounting direction, it is a rotational passive portion provided on the tip side of the bearing and coaxially with the rotation axis so as to protrude from the tip portion, and in a state where the cartridge is mounted on the apparatus body, A rotary passive unit that receives rotational power to rotate the electrophotographic photosensitive drum by engaging with a rotation driving unit provided in the apparatus main body;
A first centering portion provided on the same axis as the rotation axis so as to protrude from the rotation passive portion on the tip side of the rotation passive portion in the mounting direction, and the cartridge is mounted to the apparatus main body. A first alignment unit that engages with a second alignment unit provided in the main body of the electrophotographic image forming apparatus to align the rotation passive unit and the rotation axis of the rotation drive unit,
A member to be positioned provided in contact with the outer periphery of the bearing, and is guided by sliding with a positioning portion provided in the electrophotographic image forming apparatus body when the cartridge is mounted in the apparatus body. A member to be positioned that is positioned by the positioning unit in a state where the cartridge is mounted on the apparatus main body;
A cartridge comprising:   The cartridge according to claim 1, wherein the rotation passive portion has a convex shape, the rotation drive portion has a concave shape, and the rotation passive portion and the rotation drive portion are fitted.   The first aligning portion has a convex shape, the second aligning portion is one of a through hole, a blind hole, or a recess, and the first aligning portion and the second aligning portion are fitted to each other. The cartridge according to claim 1, wherein the cartridge is a cartridge.   4. The cartridge according to claim 1, wherein the positioned member is held by the frame in parallel with the rotation axis direction. 5.   5. The cartridge according to claim 1, wherein the member to be positioned overlaps at least a part of the rotation passive portion in the mounting direction. 6. In the mounting direction, the to-be-positioned portion is longer than the longer of the fitting length of the rotation passive portion and the rotation driving portion or the fitting length of the first alignment portion and the second alignment portion. The cartridge according to claim 1, wherein the length of the portion is long.   The positioned member is composed of two parallel rod members distributed at a right and left equal angle with respect to a perpendicular passing through the rotation center of the bearing, the positioning recess is V-shaped, and the two rod members The cartridge according to any one of claims 1 to 6, wherein each of the cartridges is supported in contact with inclined surfaces on both sides of the V-shape.   The cartridge according to any one of claims 1 to 7, wherein the cartridge includes a process unit that acts on the electrophotographic photosensitive drum, and is a process cartridge that is detachably attached to the electrophotographic image forming apparatus main body. An electrophotographic image forming apparatus.   9. The electrophotographic image forming apparatus according to claim 8, wherein the drum driving member is urged in a direction in which the drum driving member is retracted on a rotation axis by an engaging force by insertion of the cartridge and then returned to a fixed position again. apparatus.

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