PROCESS CARTRIDGE AND ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS

• US 20080159772A1
• Filed: 01/17/2007
• Published: 07/03/2008
• Est. Priority Date: 12/28/2006
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Koishi, Isao, Nittani, Susumu, Tsuzuki, Masatomo, Imaizumi, Chikara
• Granted Patent: US 7,890,012 B2
• Time in Patent Office: Days
• US Class Current: 399/90
• CPC Class Codes: G03G 15/0194 primary transfer to the final recording medium G03G15/0184 takes precedence
• CPC Class Codes: G03G 21/1623 Means to access the interior of the apparatus
• CPC Class Codes: G03G 21/1671 for the photosensitive element
• CPC Class Codes: G03G 21/1676 for the developer unit
• CPC Class Codes: G03G 21/1817 having a submodular arrangement
• CPC Class Codes: G03G 21/1853 the process cartridge being mounted perpendicular to the axis of the photosensitive member
• CPC Class Codes: G03G 21/1857 for transmitting mechanical drive power to the process cartridge, drive mechanisms, gears, couplings, braking mechanisms
• CPC Class Codes: G03G 21/1871 associated with a positioning function
• CPC Class Codes: G03G 2221/1654 Locks and means for positioning or alignment
• CPC Class Codes: G03G 2221/1657 transmitting mechanical drive power
• CPC Class Codes: G03G 2221/1684 using extractable subframes, e.g. on rails or hinges

Abstract

A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus including a movable member movable from an outside of the main assembly of the apparatus to an inside thereof while carrying the process cartridge. The cartridge includes a drum, charging and developing rollers, rotatably connected first and second frames supporting different rollers, drum and developing roller driving force receiving portions, first and second portions-to-be-supported, on one and the other ends of the first frame, first and second portions-to-be-positioned, on one and the other ends of the first frame positioned to first and second main assembly side positioning portions during a lowering movement of the movable member toward a transfer belt, charging and developing bias contacts exposed at the other end, and a portion-to-be-urged, on the first frame upper surface for receiving an elastic force to position the process cartridge relative to the main assembly.

Claims

1. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus including a movable member movable from an outside of the main assembly of the apparatus to an inside thereof while carrying said process cartridge, said process cartridge comprising:

1) an electrophotographic photosensitive drum;

2) a charging roller for charging said electrophotographic photosensitive drum;

3) a first frame for supporting said electrophotographic photosensitive drum and said charging roller;

4) a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum with a developer;

5) a second frame for supporting said developing roller, said second frame being rotatably connected with said first frame;

6) a drum driving force receiving portion, provided on one longitudinal end of said electrophotographic photosensitive drum, for receiving a driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus in a state in which process cartridge is mounted to the main assembly of the apparatus;

7) a developing roller driving force receiving portion, provided on one end of said second frame with respect to a longitudinal direction of said electrophotographic photosensitive drum, for receiving a driving force for rotating said developing roller in a direction opposite that of said electrophotographic photosensitive drum in the state in which process cartridge is mounted to the main assembly of the apparatus;

8) a first portion-to-be-supported, provided on one end of said first frame with respect to the longitudinal direction, for being supported by the movable member to support said process cartridge on said movable member;

9) a second portion-to-be-supported, provided on other end of said first frame with respect to the longitudinal direction, for being supported by said movable member to cooperate with said first portion-to-be-supported to support said process cartridge on said movable member;

10) a first portion-to-be-positioned, provided on said one longitudinal end of said first frame coaxially with said electrophotographic photosensitive drum, for being positioned to a first main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

11) a second portion-to-be-positioned, provided on said other longitudinal end of said second frame co-axially with said electrophotographic photosensitive drum, for being positioned to a second main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

12) a cartridge side charging bias contact, provided exposed at the other end, for receiving a charging bias voltage to be supplied to said charging roller from the main assembly of the apparatus in the state in which process cartridge is mounted to the main assembly of the apparatus;

13) a cartridge side developing bias contact, provided exposed at the other end, for receiving a developing bias contact to be supplied to said developing roller from the main assembly of the apparatus in the state in which process cartridge is mounted to the main assembly of the apparatus; and

14) a portion-to-be-urged, provided on an upper surface of said first frame adjacent the other longitudinal end, for receiving an inclined downward elastic force of a first main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge toward other end thereof to position the other end of said process cartridge relative to the main assembly of the apparatus and to urge said second portion-to-be positioned to the second main assembly side positioning portion, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

2. A process cartridge according to claim 1, further comprising a portion-to-be-regulated contactable to said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned when said drum driving force receiving portion and said developing roller driving force receiving portion receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

3. A process cartridge according to claim 2, wherein said portion-to-be-regulated includes a projection projected outwardly with respect to the longitudinal direction from said one longitudinal end of said first frame, and said projection is contactable to an inner surface of a recess provided in said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned.

4. A process cartridge according to claim 2 or 3, wherein said portion-to-be-regulated includes a recess which opens outwardly with respect to the longitudinal direction from the other longitudinal end of said first frame, and said projection is contactable to an outer surface of a projection provided on said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned.

5. A process cartridge according to claim 4, further comprising a second portion-to-be-urged, provided on an upper surface of said first frame adjacent said one longitudinal end, for receiving a substantially vertical downward elastic force of a second main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge downwardly thus urging said first portion-to-be-positioned to the first main assembly side positioning portion.

6. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus including a movable member movable from an outside of the main assembly of the apparatus to an inside thereof while carrying said process cartridge, said process cartridge comprising:

1) an electrophotographic photosensitive drum;

2) a first frame for supporting said electrophotographic photosensitive drum;

3) a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum with a developer;

4) a second frame for supporting said developing roller, said second frame being rotatably connected with said first frame;

5) a drum driving force receiving portion, provided on one longitudinal end of said electrophotographic photosensitive drum, for receiving a driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus in a state in which process cartridge is mounted to the main assembly of the apparatus;

6) a developing roller driving force receiving portion, provided on one end of said second frame with respect to a longitudinal direction of said electrophotographic photosensitive drum, for receiving a driving force for rotating said developing roller in a direction opposite that of said electrophotographic photosensitive drum in the state in which process cartridge is mounted to the main assembly of the apparatus;

7) a first portion-to-be-supported, provided on one end of said first frame with respect to the longitudinal direction, for being supported by the movable member to support said process cartridge on said movable member;

8) a second portion-to-be-supported, provided on other end of said first frame with respect to the longitudinal direction, for being supported by said movable member to cooperate with said first portion-to-be-supported to support said process cartridge on said movable member;

9) a first portion-to-be-positioned, provided on said one longitudinal end of said first frame axially with said electrophotographic photosensitive drum, for being positioned to a first main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

10) a second portion-to-be-positioned, provided on said other longitudinal end of said second frame co-axially with said electrophotographic photosensitive drum, for being positioned to a second main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt; and

11) a portion-to-be-regulated contactable to said movable member to prevent said process cartridge from rotating about said first portion-to-be positioned and said second portion-to-be-positioned when said drum driving force receiving portion and said developing roller driving force receiving portion receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

7. A process cartridge according to claim 6, wherein said portion-to-be-regulated includes a projection projected outwardly with respect to the longitudinal direction from said one longitudinal end of said first frame, and said projection is contactable to an inner surface of a recess provided in said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned.

8. A process cartridge according to claim 6 or 7, herein said portion-to-be-regulated includes a recess which opens outwardly with respect to the longitudinal direction from the other longitudinal end of said first frame, and said projection is contactable to an outer surface of a projection provided on said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned.

9. An apparatus according to claim 6, further comprising a second portion-to-be-urged, provided on an upper surface of said first frame adjacent said one longitudinal end, for receiving a substantially vertical downward elastic force of a second main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge downwardly thus urging said first portion-to-be-positioned to the first main assembly side positioning portion.

10. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus including a movable member movable from an outside of the main assembly of the apparatus to an inside thereof while carrying said process cartridge, said process cartridge comprising:

1) an electrophotographic photosensitive drum;

2) a first frame for supporting said electrophotographic photosensitive drum;

3) a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum with a developer;

4) a second frame for supporting said developing roller, said second frame being rotatably connected with said first frame;

5) a drum driving force receiving coupling, provided on one longitudinal end of said electrophotographic photosensitive drum, for receiving a driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus in a state in which process cartridge is mounted to the main assembly of the apparatus;

6) a developing roller driving force receiving coupling, provided on one end of said second frame with respect to a longitudinal direction of said electrophotographic photosensitive drum, for receiving a driving force for rotating said developing roller in a direction opposite that of said electrophotographic photosensitive drum in the state in which process cartridge is mounted to the main assembly of the apparatus;

7) a first portion-to-be-supported, provided on one end of said first frame with respect to the longitudinal direction, for being supported by the movable member to support said process cartridge on said movable member;

8) a second portion-to-be-supported, provided on other end of said first frame with respect to the longitudinal direction, for being supported by said movable member to cooperate with said first portion-to-be-supported to support said process cartridge on said movable member;

9) a first portion-to-be-positioned, provided on said one longitudinal end of said first frame coaxially with said electrophotographic photosensitive drum, for being positioned to a first main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

10) a second portion-to-be-positioned, provided on said other longitudinal end of said second frame co-axially with said electrophotographic photosensitive drum, for being positioned to a second main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

11) a first portion-to-be-urged, provided on an upper surface of said first frame adjacent the other longitudinal end, for receiving an inclined downward elastic force of a first main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge toward other end thereof to position the other end of said process cartridge relative to the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

12) a second portion-to-be-urged, provided on an upper surface of said first frame adjacent said one longitudinal end, for receiving a substantially vertical downward elastic force of a second main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge downwardly thus urging said first portion-to-be-positioned to the first main assembly side positioning portion.

13) a projection, provided projected longitudinally outwardly from said one longitudinal end of said first frame, for being contacted by an inner surface of a recess provided in the movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned when said drum driving force receiving coupling and said developing roller driving force receiving coupling receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion; and

14) a recess, provided in the other longitudinal end of said first frame and opening longitudinally outwardly, for being contacted by an outer surface of a projection provided in the movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned when said drum driving force receiving coupling and said developing roller driving force receiving coupling receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

11. An electrophotographic image forming apparatus, to which a process cartridge is detachably mountable, for forming an image on a recording material, said apparatus comprising:

1) a movable member which is linearly movable between an inside and an outside of a main assembly of the electrophotographic image forming apparatus while carrying a plurality of such process cartridges;

2) a first main assembly side positioning portion;

3) a second main assembly side positioning portion;

4) a first main assembly side elastic member;

5) a transfer belt;

6) an output charging bias contact;

7) an output developing bias contact; and

8) a process cartridge including,

a electrophotographic photosensitive drum;

a charging roller for charging said electrophotographic photosensitive drum;

a first frame for supporting said electrophotographic photosensitive drum and said charging roller;

a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum with a developer;

a second frame for supporting said developing roller, said second frame being rotatably connected with said first frame;

a drum driving force receiving portion, provided on one longitudinal end of said electrophotographic photosensitive drum, for receiving a driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus in a state in which process cartridge is mounted to the main assembly of the apparatus;

a developing roller driving force receiving portion, provided on one end of said second frame with respect to a longitudinal direction of said electrophotographic photosensitive drum, for receiving a driving force for rotating said developing roller in a direction opposite that of said electrophotographic photosensitive drum in the state in which process cartridge is mounted to the main assembly of the apparatus;

a first portion-to-be-supported, provided on one end of said first frame with respect to the longitudinal direction, for being supported by the movable member to support said process cartridge on said movable member;

a second portion-to-be-supported, provided on other end of said first frame with respect to the longitudinal direction, for being supported by said movable member to cooperate with said first portion-to-be-supported to support said process cartridge on said movable member;

a first portion-to-be-positioned, provided on said one longitudinal end of said first frame coaxially with said electrophotographic photosensitive drum, for being positioned to a first main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

a second portion-to-be-positioned, provided on said other longitudinal end of said second frame coaxially with said electrophotographic photosensitive drum, for being positioned to a second main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

a cartridge side charging bias contact, provided exposed at the other end, for receiving a charging bias voltage to be supplied to said charging roller from the main assembly of the apparatus in the state in which process cartridge is mounted to the main assembly of the apparatus;

a cartridge side developing bias contact, provided exposed at the other end, for receiving a developing bias contact to be supplied to said developing roller from the main assembly of the apparatus in the state in which process cartridge is mounted to the main assembly of the apparatus; and

a portion-to-be-urged, provided on an upper surface of said first frame adjacent the other longitudinal end, for receiving an inclined downward elastic force of a first main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge toward other end thereof to position the other end of said process cartridge relative to the main assembly of the apparatus and to urge said second portion-to-be-positioned to the second main assembly side positioning portion, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

14. An apparatus according to claim 11, wherein said process cartridge further includes a portion-to-be-regulated contactable to said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned when said drum driving force receiving portion and said developing roller driving force receiving portion receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

16. An apparatus according to claim 14, wherein said portion-to-be-regulated includes a recess which opens outwardly with respect to the longitudinal direction from the other longitudinal end of said first frame, and said projection is contactable to an outer surface of a projection provided on said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned.

17. An apparatus according to claim 16, wherein said process cartridge further includes a second portion-to-be-urged, provided on an upper surface of said first frame adjacent said one longitudinal end, for receiving a substantially vertical downward elastic force of a second main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge downwardly thus urging said first portion-to-be-positioned to the first main assembly side positioning portion.

12. An electrophotographic image forming apparatus, to which a process cartridge is detachably mountable, for forming an image on a recording material, said apparatus comprising:

1) a movable member which is linearly movable between an inside and an outside of a main assembly of the electrophotographic image forming apparatus while carrying a plurality of such process cartridges;

2) a first main assembly side positioning portion;

3) a second main assembly side positioning portion;

4) a transfer belt; and

5) a process cartridge including,

a electrophotographic photosensitive drum;

a first frame for supporting said electrophotographic photosensitive drum;

a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum with a developer;

a second frame for supporting said developing roller, said second frame being rotatably connected with said first frame;

a drum driving force receiving portion, provided on one longitudinal end of said electrophotographic photosensitive drum, for receiving a driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus in a state in which process cartridge is mounted to the main assembly of the apparatus;

a developing roller driving force receiving portion, provided on one end of said second frame with respect to a longitudinal direction of said electrophotographic photosensitive drum, for receiving a driving force for rotating said developing roller in a direction opposite that of said electrophotographic photosensitive drum in the state in which process cartridge is mounted to the main assembly of the apparatus;

a first portion-to-be-supported, provided on one end of said first frame with respect to the longitudinal direction, for being supported by the movable member to support said process cartridge on said movable member;

a second portion-to-be-supported, provided on other end of said first frame with respect to the longitudinal direction, for being supported by said movable member to cooperate with said first portion-to-be-supported to support said process cartridge on said movable member;

a first portion-to-be-positioned, provided on said one longitudinal end of said first frame coaxially with said electrophotographic photosensitive drum, for being positioned to a first main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

a second portion-to-be-positioned, provided on said other longitudinal end of said second frame coaxially with said electrophotographic photosensitive drum, for being positioned to a second main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt; and

a portion-to-be-regulated contactable to said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned when said drum driving force receiving portion and said developing roller driving force receiving portion receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

15. An apparatus according to claim 12 or 14, wherein said portion-to-be-regulated includes a projection projected outwardly with respect to the longitudinal direction from said one longitudinal end of said first frame, and said projection is contactable to an inner surface of a recess provided in said movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned.

13. An electrophotographic image forming apparatus, to which a process cartridge is detachably mountable, for forming an image on a recording material, said apparatus comprising:

1) a movable member which is linearly movable between an inside and an outside of a main assembly of the electrophotographic image forming apparatus while carrying a plurality of such process cartridges;

2) a first main assembly side positioning portion;

3) a second main assembly side positioning portion;

4) a first main assembly side elastic member;

5) a second main assembly side elastic member;

6) a transfer belt; and

7) a process cartridge including,

a electrophotographic photosensitive drum;

a first frame for supporting said electrophotographic photosensitive drum;

a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum with a developer;

a second frame for supporting said developing roller, said second frame being rotatably connected with said first frame;

a drum driving force receiving coupling, provided on one longitudinal end of said electrophotographic photosensitive drum, for receiving a driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus in a state in which process cartridge is mounted to the main assembly of the apparatus;

a developing roller driving force receiving coupling, provided on one end of said second frame with respect to a longitudinal direction of said electrophotographic photosensitive drum, for receiving a driving force for rotating said developing roller in a direction opposite that of said electrophotographic photosensitive drum in the state in which process cartridge is mounted to the main assembly of the apparatus;

a first portion-to-be-supported, provided on one end of said first frame with respect to the longitudinal direction, for being supported by the movable member to support said process cartridge on said movable member;

a second portion-to-be-supported, provided on other end of said first frame with respect to the longitudinal direction, for being supported by said movable member to cooperate with said first portion-to-be-supported to support said process cartridge on said movable member;

a first portion-to-be-positioned, provided on said one longitudinal end of said first frame axially with said electrophotographic photosensitive drum, for being positioned to a first main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

a second portion-to-be-positioned, provided on said other longitudinal end of said second frame coaxially with said electrophotographic photosensitive drum, for being positioned to a second main assembly side positioning portion provided in the main assembly of the apparatus during a lowering movement of said movable member toward the transfer belt;

a first portion-to-be-urged, provided on an upper surface of said first frame adjacent the other longitudinal end, for receiving an inclined downward elastic force of a first main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge toward other end thereof to position the other end of said process cartridge relative to the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.

a second portion-to-be-urged, provided on an upper surface of said first frame adjacent said one longitudinal end, for receiving a substantially vertical downward elastic force of a second main assembly side elastic member provided in the main assembly of the apparatus to urge said process cartridge downwardly thus urging said first portion-to-be-positioned to the first main assembly side positioning portion.

a projection, provided projected longitudinally outwardly from said one longitudinal end of said first frame, for being contacted by an inner surface of a recess provided in the movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned when said drum driving force receiving coupling and said developing roller driving force receiving coupling receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion; and

a recess, provided in the other longitudinal end of said first frame and opening longitudinally outwardly, for being contacted by an outer surface of a projection provided in the movable member to prevent said process cartridge from rotating about said first portion-to-be-positioned and said second portion-to-be-positioned when said drum driving force receiving coupling and said developing roller driving force receiving coupling receive the rotational driving forces from the main assembly of the apparatus, in a state in which first portion-to-be-positioned is positioned to the first main assembly side positioning portion and in which said second portion-to-be-positioned is positioned to the second main assembly side positioning portion.