This application is based on application Ser. No. 2000-45858 filed in Japan on Feb. 23, 2000, the contents of which are hereby incorporated by reference.
The present invention relates to a process cartridge and an image forming apparatus using the same.
In an image forming apparatus used in a copying machine, a printer or the like, for the purposes of exchanging or repairing elements necessary for image forming processes, treating a jam or the like, process cartridges including the elements are detachably mounted on the image forming apparatus. Such process cartridges are necessary to be securely mounted and positioned on the image forming apparatus so as not to cause a maloperation.
U.S. Pat. No. 5,066,976 proposes such a mechanism that if a process cartridge is not perfectly push into an apparatus body, a part of holding member for holding the process cartridge protrudes out of an opening portion of grip, whereby it can be possible to judge whether or not the process cartridge is pushed into a predetermined position. Japanese Utility Model Laid-open publication No. 63-100736 proposes such a mechanism that when a cover is closed, a stopper mechanism provided on the cover pushes and fixes a process unit. Japanese Utility Model Laid-open publication No. 62-149046 proposes such a mechanism that a process unit detachably mounted so as to approach to and separate from a photosensitive is moved by a lever to position in place.
However, the positioning mechanisms of process cartridges proposed above have a disadvantage that when the process cartridges are positioned in a half-locked state or a half-inserted condition, or when the operation of the lever is omitted, the positioning of the process cartridges has to be conducted again, and also have a disadvantage that the push-fixation mechanism is complicated.
Accordingly, it is an object of the present invention to provide a process cartridge which has a simple mechanism and can be easily positioned with respect to an apparatus body and securely mounted on the apparatus body even in a half-locked state or a half-inserted condition, and also provide an image forming apparatus using the process cartridge.
According to a first aspect of the present invention, there is provided a process cartridge which can be mounted on and dismounted from an image forming apparatus, the process cartridge comprising:
a unit comprising an element used for an image forming process;
a positioning member having a positioning member which engages with an engagement portion formed on the image forming apparatus to position the process cartridge at a predetermined mount position in the image forming apparatus;
a holding member for holding the unit to allow displacement of the unit relative to the positioning member; and
a restricting and releasing mechanism for restricting or releasing the displacement of the unit relative to the positioning member.
In the first aspect of the present invention, when the process cartridge is mounted on the image forming apparatus, the unit is secured by restricting the displacement of the unit relative to the positioning member, it is possible to stably surely mount the process unit. The term xe2x80x9cdisplacementxe2x80x9d in this specification of the present invention includes pivot, vibration, movement, swing and so on.
It is preferable that the engagement portion of the image forming apparatus comprises a recess or projection, and wherein the positioning member comprises a projection or recess which engages with the recess or projection of the engagement portion. In this case, the projection or recess of the positioning member may comprise a plurality of projections or recesses which are disposed around the holding member.
Preferably, the holding member comprises a screw member.
Preferably, the process cartridge further comprises a cover member for interlocking with the restricting and releasing mechanism to cover or open a specific portion of the unit. In this case, the element may comprise a toner container and a developing roller, and cover member may cover or open the developing roller.
Preferably, the restricting and releasing mechanism comes into contact with a member provided on the image forming apparatus and operates. In this case, the restricting and releasing mechanism may operate when the process cartridge is mounted on and dismounted from the image forming apparatus. Alternately, the restricting and releasing mechanism mat operate when the process cartridge is mounted on the image forming apparatus.
According to a second aspect of the present invention, there is provided a process cartridge which can be mounted on and dismounted from an image forming apparatus, the process cartridge comprising:
a unit comprising an element used for an image forming process;
a positioning member having a first positioning member which engages with an engagement portion formed on the image forming apparatus to position the process cartridge at a first predetermined position in the image forming apparatus; and
a first pressed portion which is pressed by a first press portion provided on the image forming apparatus when the process cartridge is moved from the first predetermined position to a second predetermined position to position the process cartridge at the second predetermined position.
In the second aspect of the present invention, when the process cartridge moves in the image forming apparatus, the first pressed portion of the process cartridge is pressed by the first press portion of the image forming apparatus and positioned in place, whereby the process cartridge can be securely mounted in the predetermined position even in an incompletely mounted condition.
It is preferable that the engagement portion of the image forming apparatus comprises a recess or projection, and wherein the positioning member comprises a projection or recess which engages with the recess or projection of the engagement portion.
Preferably, the first pressed portion is provided on the positioning member.
preferably, the process cartridge further comprises a second pressed portion which is pressed by a second press portion provided on a cover of the image forming apparatus when closing the cover, the process cartridge is positioned at the first predetermined position by pressing the second press portion on the second pressed portion. In this case, the second pressed portion may be provided on the positioning member. The second pressed portion may be the first pressed portion.
Preferably, the process cartridge may further comprises a third pressed portion which is pressed by a third press portion provided on the image forming apparatus when the process cartridge is moved from the second predetermined position to a third predetermined position to position the process cartridge at the third predetermined position. In this case, the pressing direction by the third press portion may be substantially perpendicular to the pressing direction by the first press portion. When the process cartridge is positioned at the third predetermined position, the first and second pressed portions are not pressed by the first and second press portion.
Preferably, the pressing direction by the first and second press portions may be identical to the direction that the process cartridge is mounted on the image forming apparatus.
According to a third aspect of the present invention, there is provided an image forming apparatus, comprising:
a process cartridge comprising:
a unit comprising an element used for an image forming process;
a positioning member having a positioning member;
a holding member for holding the unit to allow displacement of the unit relative to the positioning member; and
a restricting and releasing mechanism for restricting or releasing the displacement of the unit relative to the positioning member;
an image forming unit for forming an image using the element of the process cartridge; and
an engagement portion which engages with the positioning member of the process cartridge to position the process cartridge at a predetermined mount position in the image forming apparatus.
According to a fourth aspect of the present invention, there is provided an image forming apparatus, comprising:
a process cartridge comprising:
a unit comprising an element used for an image forming process;
a positioning member having a first positioning member; and
a first pressed portion;
an image forming unit for forming an image using the element of the process cartridge;
an engagement portion which engages with the positioning member of the process cartridge to position the process cartridge at a first predetermined position in the image forming apparatus; and
a first press portion for pressing the first pressed portion of the process cartridge when the process cartridge is moved from the first predetermined position to a second predetermined position to position the process cartridge at the second predetermined position.