Claims
- 1. A sheet supplying and conveying apparatus comprising:
- a sheet supporting means for supporting sheets;
- a convey roller contacted with the sheet supported by said sheet supporting means with a predetermined sheet supplying pressure for feeding out the sheet and conveying the sheet around said convey roller by a rotation thereof;
- a separation rotary member urged against said convey roller with predetermined separation pressure for separating the sheets fed out by said convey roller one by one;
- a torque limiter (i) for permitting rotation of said separation rotary member in a sheet conveying direction when a rotational torque directing toward the sheet conveying direction and having a value greater than a predetermined value acts on said separation rotary member and (ii) for preventing the rotation of said separation rotary member in the sheet conveying direction when the rotational torque having a value smaller than the predetermined value acts on said separation rotary member; and
- a pressure releasing means for releasing the sheet supplying pressure and the separation pressure on the way of the conveyance of the sheet by said convey roller.
- 2. A sheet supplying and conveying apparatus according to claim 1, wherein said sheet supporting means has a sheet support member for supporting the sheets, and a biasing means for biasing said sheet support member toward said convey roller to urge the sheets supported by said sheet support member against said convey roller; and, said pressure releasing means has a sheet supplying pressure releasing means for shifting said sheet support member away from said convey roller in opposition to a biasing force of said biasing means, and a separation pressure releasing means for separating said separation rotary member from said convey roller when said sheet support member is shifted away from said convey roller by said sheet supplying pressure releasing means.
- 3. A sheet supplying and conveying apparatus according to claim 2, wherein said sheet support member is a pivotable pressure plate, and said biasing means is a spring for elastically biasing said pressure plate toward said convey roller; wherein said sheet supplying pressure releasing means is so designed as to separate said pressure plate from said convey roller in opposition to an elastic force of said spring.
- 4. A sheet supplying and conveying apparatus according to claim 3, wherein said sheet supplying pressure releasing means has a cam which can be rotated to slidably contacted with said pressure plate, and a rotation controlling means for rotating said cam by a predetermined amount.
- 5. A sheet supplying and conveying apparatus according to claim 2 or 3, wherein said separation rotary member is attached to a holder; and further comprising a spring for biasing said holder toward said convey roller to urge said separation rotary member against said convey roller, wherein said separation pressure releasing means includes an engagement portion provided on said pressure plate so that, when said pressure plate is shifted by said sheet supplying pressure releasing means, said engagement portion is engaged by said holder to separate said separation rotary member from said convey roller in opposition to an elastic force of said spring.
- 6. A sheet supplying and conveying apparatus according to claim 5, wherein said separation rotary member has a separation roller rotatably supported by a shaft secured to said holder, and said torque limiter has a coil spring wound around said shaft with a predetermined tightening force and having one end connected to said separation roller so that, (i) when said separation roller is subjected to rotational torque having a predetermined value or more in the sheet conveying direction, said coil spring is loosened to release the tightening force, thereby rotating said separation roller, and (ii) when said separation roller is subjected to rotational torque smaller than said predetermined value, the rotation of said separation roller is regulated by the tightening force of said coil spring.
- 7. A sheet supplying and conveying apparatus according to claim 2, further comprising a sheet returning means shifted from a downstream side to an upstream side to return a sheet remaining in the vicinity of a nip between said convey roller and said separation rotary member to said sheet supporting means when said separation rotary member is separated from said convey roller by said separation pressure releasing means.
- 8. A sheet supplying and conveying apparatus according to claim 7, wherein said sheet returning means has a return lever pivotally disposed in the vicinity of the nip between said convey roller and said separation rotary member, and a spring for biasing said return lever to return said return lever from the downstream side to the upstream side, and a spring force of said spring is set to shift said return lever toward the downstream side by the sheet conveyed by said convey roller.
- 9. A sheet supplying and conveying apparatus according to claim 1, further comprising a drive transmitting means for rotating said separation rotary member in a reverse direction, and said torque limiter is designed so that, (i) when said drive transmitting means is subjected to rotational torque having a predetermined value or more, drive transmission is interrupted, whereby, when said separation rotary member is subjected to the rotational torque having the predetermined value or more, the drive in the reverse direction is interrupted, and (ii) when said separation rotary member is subjected to rotational torque smaller than said predetermined value, the drive in the reverse direction is transmitted to said separation rotary member.
- 10. A sheet supplying and conveying apparatus according to claim 1, further comprising a guide means for guiding the sheet along a periphery of said convey roller to U-return and convey the sheet being conveyed by said guide means.
- 11. A sheet supplying and conveying apparatus according to claim 10, wherein said guide means has a guide plate disposed along the periphery of said convey roller, and a pinch roller urged against said convey roller.
- 12. A sheet supplying and conveying apparatus according to claim 1, wherein said convey roller is constituted by a plurality of elastic rollers disposed coaxially, and said separation rotary member is urged against at least one of said elastic rollers and pinch rollers are urged against the other elastic rollers to separate and convey the sheet.
- 13. A sheet supplying and conveying apparatus according to claim 12, wherein a hardness of the elastic roller against which said separation rotary member is urged is smaller than that of the other elastic rollers.
- 14. A sheet supplying and conveying apparatus according to claim 13, wherein a frictional coefficient of the elastic roller against which said separation rotary member is urged is greater than that of the other elastic rollers.
- 15. A sheet supplying and conveying apparatus comprising:
- a liftable/lowerable sheet supporting means for supporting sheets;
- a convey roller having a function for feeding out the sheet supported by said sheet supporting means and a function for conveying the fed sheet;
- a guide means disposed along a periphery of said convey roller for cooperating with said convey roller to convey the sheet; and
- a separation means urged against said convey roller for separating the sheets from said sheet supporting means by said convey roller one by one;
- wherein said convey roller is constituted by a plurality of elastic rollers disposed coaxially, and a hardness of the elastic roller against which said separation means is urged is smaller than that of the other elastic rollers.
- 16. A sheet supplying and conveying apparatus according to claim 15, wherein a frictional coefficient of the elastic roller against which said separation means is urged is greater than those of the other elastic rollers.
- 17. A sheet supplying and conveying apparatus according to claim 15 or 16, wherein said separation means is urged against the central elastic roller disposed among said plurality of elastic rollers.
- 18. A sheet supplying and conveying apparatus according to claim 15, wherein said guide means has a guide plate disposed along the periphery of said convey roller, and pinch rollers urged against said other elastic rollers against which said separation means is not urged.
- 19. A sheet supplying and conveying apparatus according to claim 18, wherein said convey roller and said guide means define a convey path through which the sheet is U-turned and conveyed.
- 20. A recording apparatus comprising:
- a sheet supporting means for supporting sheets;
- a convey roller contacted with the sheet supported by said sheet supporting means with a predetermined sheet supplying pressure and for feeding out the sheet and conveying the sheet around said convey roller by a rotation of said convey roller;
- a separation rotary member urged against said convey roller with predetermined separation pressure for separating the sheets fed out by said convey roller one by one;
- a torque limiter (i) for permitting a rotation of said separation rotary member in a sheet conveying direction when rotational torque directing toward the sheet conveying direction and having a value greater than a predetermined value acts on said separation rotary member, and (ii) for preventing the rotation of said separation rotary member in the sheet conveying direction when the rotational torque having a value smaller than the predetermined value acts on said separation rotary member;
- a pressure releasing means for releasing the sheet supplying pressure and the separation pressure on the way of the conveyance of the sheet by said convey roller; and
- a recording means for executing recording to the sheet conveyed by said convey roller.
- 21. A recording apparatus comprising:
- a liftable/lowerable sheet supporting means for supporting sheets;
- a convey roller having a function for feeding out the sheet supported by said sheet supporting means and a function for conveying the fed sheets;
- a guide means disposed along a periphery of said convey roller for cooperating with said convey roller to convey the sheet;
- a separation means urged against said convey roller for separating the sheets from said sheet supporting means by said convey roller one by one; and
- a recording means for executing recording to the sheet conveyed by said convey roller;
- wherein said convey roller is constituted by a plurality of elastic rollers disposed on a common shaft, and hardness of the elastic roller against which said separation means is urged is smaller than those of the other elastic rollers.
- 22. A recording apparatus comprising:
- recording means for recording an image on a sheet;
- sheet supporting means for supporting the sheets to be recorded on by said recording means;
- a convey roller in contact with an uppermost sheet of the sheets supported by said sheet supporting means for feeding out the uppermost sheet from said sheet supporting means, said convey roller also conveying the sheet when said recording means records the image on the sheet;
- a separation rotary member urged against said convey roller for separating the sheets fed out by said convey roller one by one;
- a torque limiter (i) for permitting rotation of said separation rotary member in a sheet conveying direction when a rotational torque directed toward the sheet conveying direction and having a value greater than a predetermined value acts on said separation rotary member, and (ii) for preventing the rotation of said separation rotary member in the sheet conveying direction when the rotational torque having a value smaller than the predetermined value acts on said separation convey member; and
- releasing means for releasing the contact between said convey roller and the sheet supported by said sheet supporting means and the urge of said separation rotary member, during conveyance of the sheet by said convey roller.
- 23. A recording apparatus according to claim 22, wherein said convey roller conveys the sheet along a periphery of said convey roller in an U-return fashion, and said recording means records the image on the sheet U-returned by said convey roller.
- 24. A recording apparatus according to claim 23, wherein said sheet support means has a pivotable sheet support member for supporting the sheets and is biased by a first biasing means toward said convey roller; and said separation rotary member is biased towards said convey roller by a second biasing means, and
- said releasing means separates said sheet support member from said convey roller in opposition to a bias force of said first biasing means and separates said separation rotary member from said convey roller in opposition to a biasing force of said second biasing means.
- 25. A recording apparatus according to claim 22, wherein said recording means utilized an ink jet recording method for forming the image in which an ink is discharged by using thermal energy generated by an electrical-thermal converter.
Priority Claims (1)
Number |
Date |
Country |
Kind |
7-084288 |
Apr 1995 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 08/628,447, filed Apr. 5, 1996, now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (4)
Number |
Date |
Country |
357027839A |
Feb 1982 |
JPX |
62-105834 |
May 1987 |
JPX |
1-139286 |
May 1989 |
JPX |
2 140 784 |
Dec 1984 |
GBX |
Non-Patent Literature Citations (2)
Entry |
Patent Abstracts of Japan, vol. 017, No. 330 (M-1434), 23 Jun. 1993 & JP 05-03931 A (Matsushita Electric Ind. Co. Ltd.), 19 Feb. 1993. |
Patent Abstracts of Japan, vol. 018, No. 508 (M-1678), 26 Sep. 1994 & JP 06-171783 A (Ricoh Co. Ltd.) 21 Jun. 1994. |
Continuations (1)
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Number |
Date |
Country |
Parent |
628447 |
Apr 1996 |
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