Claims
- 1. An image forming apparatus for transcribing a toner image produced on the rotating surface of an image forming drum onto a recording medium, said image forming apparatus comprising:
- a developing unit for visualizing the toner image on the image forming drum by developing an electrostatic image formed on the image forming drum, said developing unit being juxtaposed the image forming drum so as to produce a first gap between said developing unit and the image forming drum at a predetermined value when an upper and a lower frame are closed relative to each other;
- said upper frame supporting the image forming drum and said developing unit;
- said lower frame being pivotally connected to said upper frame so that said upper frame is openable, leaving said lower frame stationary, said lower frame including first connecting means for rotatably connecting said upper frame and said lower frame; and
- link means pivotally coupled to both said upper and lower frames for moving said developing unit away from the image forming drum, when said upper frame is opened, the link means being expandable and contractible in accordance with movement of the upper frame so as to produce a second gap between said developing unit and the image forming drum, said second gap being sufficiently wide to permit the developing unit and the image forming drum to be dismounted from or mounted to said upper frame without contacting each other.
- 2. An image doming apparatus according to claim 1, wherein said upper frame further comprises:
- first mounting means for mounting and demounting said developing unit into and from said upper frame respectively in a first direction parallel with a rotational axis of the image forming drum; and
- second mounting means for allowing said developing unit to be moved in a second direction perpendicular to the first direction when said developing unit is united with the image forming drum, having the first gap between said developing unit and the image forming drum.
- 3. An image forming apparatus according to claim 2, wherein said link means comprises:
- a first lever rotatably attached to said upper frame by second connecting means positioned near and above the first connecting means, said first lever having a first arm short from the second connecting means and a second arm long from said second connecting means, said first arm having third connecting means at the end thereof, said second arm having a slide hole at the end thereof, through which fourth connecting means attached to said lower frame is passed so that said first lever can be rotated around the second connecting means and the fourth connecting means, sliding along the slide hole, and positional relationship among the first, second and fourth connecting means being such that a first acute angle made by a line passing through the points of the first and second connecting means and a line passing through the points of the second and fourth connecting means increases when said upper frame is opened.
- a rotation shaft provided to said upper frame in parallel with the first direction;
- a second lever attached to said rotatory shaft, said second lever having fifth connecting means at the end thereof;
- a link member connecting the first arm of said first lever and said second lever through the third connecting means and the fifth connecting means respectively, for transferring the rotating motion of said first lever to said rotation shaft so that when the first acute angle increases in accordance with the opening of said upper frame, a second acute angle made by a line passing through the positions of an axis of said rotatory shaft and the first connecting means and a line passing through the positions of the axis of said rotatory shaft and said second lever increases;
- first spring lever means, attached to said rotatory shaft, for pushing said developing unit toward the cylindrical surface in the second direction so as to have the first gap between said developing unit and the cylindrical surface when said upper frame is closed, decreasing the second acute angle; and
- second spring lever means, attached to said rotatory shaft, for separating said developing unit from the cylindrical surface in the second direction so as to have the second gap between said developing unit and the cylindrical surface when said upper frame is opened, increasing the second acute angle.
- 4. A linkage mechanism provided between first and second frame members, of an image forming apparatus, which are movable relative to each other between open and closed positions, one of the frame member carrying a developing unit and an image forming drum, comprising:
- linkage means coupled to both the first and second frame members, and being movable in response to relative movement between the first and second frame member; and
- sliding means for slideably supporting the developing unit in the one frame member, and being actuated by the linkage means for movement between first and second positions.
- 5. A linkage mechanism according to claim 4, wherein the first and second frame members are connected for pivotal movement relative to each other.
- 6. A linkage mechanism according to claim 5, wherein the linkage means includes a first pivotal lever operatively coupled to the sliding means and being operative to impart sliding movement to the sliding means in response to relative pivotal movement between the first and second frame members.
- 7. A linkage mechanism according to claim 6, wherein the linkage means includes a second pivotal lever pivotally connected between the first and second frame members, and being operative to impart pivotal movement to the first pivotal lever in response to relative pivotal movement between the firs and second frame members.
- 8. A linkage mechanism according to claim 7, further comprising a link connecting the first and second pivotal levers.
- 9. A linkage mechanism according to claim 7, wherein the second pivotal lever has a slot formed at one end providing a sliding, pivotal connection between the first and second frame members.
- 10. A linkage mechanism according to claim 6, wherein the first pivotal lever includes a first flat spring for pushing the sliding means towards the image forming drum and a second flat spring for pulling the sliding means away from the image forming drum.
- 11. A linkage mechanism according to claim 10, further comprising a spacer disposed between the first and second flat springs.
Priority Claims (1)
Number |
Date |
Country |
Kind |
62-250992 |
Oct 1987 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 250,174, filed on Sept. 28, 1988, now abandoned.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
3689146 |
Ito et al. |
Sep 1972 |
|
4609277 |
Yokoyama et al. |
Sep 1986 |
|
4615605 |
Kida et al. |
Oct 1986 |
|
4641947 |
Ishida et al. |
Feb 1987 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
2184396 |
Jun 1987 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
250174 |
Sep 1988 |
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