Document conveyance apparatus

Abstract: A document conveyor for conveying a document to a predetermined position on a platen glass of a copying machine, comprising; a document feeder for feeding the document from outside of the document conveyer to a conveyance roller, the conveyance roller, located on the platen glass, for conveying the document onto the platen glass by rotating in the forward direction, the conveyance roller for subsequently bringing the trailing edge of the document into contact with an edge setting member, located adjacent to the platen glass, by rotating in the reverse direction so that the document is set at the predetermined position on the platen glass, an auxiliary conveyance roller, located on the platen glass, for conveying the document onto the platen glass by functioning with the conveyance roller when the document is longer than a predetermined size, and a roller retractor for retracting the auxiliary conveyance roller from the platen glass so that the auxiliary conveyance roller does not convey the document, in which the auxiliary conveyance roller is retracted from the platen glass by the roller retractor while the document is being brought into contact with the setting edge member by the conveyance roller.

Description: The present invention relates to improvement of a document conveyance apparatus according to the preamble of claim 1, which automatically feeds the document onto the document table (platen glass) of a copier, image reading equipment, etc. and discharges the document after processing from such document table. Generally, the document conveyance apparatus of this type is composed of the document store (paper feeding tray) placed on the side of document table, the document feeding means for feeding the document one by one onto the above document table from such paper feeding tray, the document conveyance means placed on the above document table which conveys the document fed from the above document feeding means, places it correctly on the exposure position on the above document base surface and discharges the document from the above document base upon completion of a prescribed number of exposures, and the paper discharging means which collects the documents, for which exposure has been completed, and places them on the discharging paper tray. This document conveyance apparatus was provided with the document conveying means for conveying the document by pressing the document against the platen glass surface with white endless belt on the platen glass of a copier and also by movement of such belt. In other words, this document conveyance means pressed the document by covering the entire surface of the platen glass with the endless belt and simultaneously conveyed it while generating frictional force with appropriate places on the document surface via slight slackness therebetween. On account of the above arrangement, there were the following problematic points: 1 Space in the thickness direction became necessary to allow for the belt rotation, thereby increasing the height of the equipment proper, and the equipment became large. 2 Maintenance quality was not satisfactory because of lowering of the pressing force with the passage of time due to fatigue or degradation of the belt and also because of frequent troubles due to lack in elasticity. 3 A large-sized motor of high output had to be used, because the belt was rotated while sliding it on the platen glass. Applicant of the present invention has earlier improved the above problematic points, and has proposed a document conveyance apparatus which can realize simultaneously reduction in equipment thickness and improvement in maintenance quality (GB-A-2213805). The document conveyance apparatus of the present invention is so constructed to have low overall apparatus height and also to permit the document conveyance without use of an endless belt, where the document holding sheet member (white-colored fixing sheet member, hereinafter called the sheet member) is provided along the platen glass surface in the apparatus proper placed above the copier and the document conveyance roller is slidably contacted to the above platen glass surface via perforated holes provided at appropriate places in such sheet member. The document conveyance roller in the above document conveyance apparatus consists of a multiple number of rollers for conveying documents of various sizes on the platen glass, and each roller will have the rotating force transmitted thereto from the driving source. In this document conveyance apparatus, the document is normally conveyed into the space between the platen glass surface and the document holding sheet by its conveyor, then such document is sent in reverse direction, so that it will run against the stopper board (striking board) for the document rear end, in determining and stopping the document at the correction position, then exposure will be made on the document in such striking and stopping conditions. Fig. 21 is a plan view showing the document sizes and the layout of conveying rollers. In the diagram, the document of various sizes will stop at the striking board 12 in the extreme left of the document table (platen glass) 11, where the document will have exposure process. On the upper surface of the above document table there are provided document conveying rollers 301, 302, 303 and the white-colored sheet member 304 of the document conveyance apparatus. However, in such document conveyance apparatus, when a document is conveyed toward the striking board on the document table, in the case of a document of the smallest size, for example, B6 size or B5 size document, such document will be conveyed under pressure contact, being slidably moved by one set of the document conveying rollers closest to the striking board, and in the case of a document of the largest size, for example, A3 size document, such document will be conveyed under pressure contact, being slidably moved by a number of document conveying roller sets. In this manner, with respect to documents of each size which are run against the striking board, in the case of a document of small size, its striking force will be small, being run and stricken only by the sliding conveying force of one set of the document conveying rollers closest to the striking board, and in the case of a document of medium size and in the case of a document of large size, they are run and stricken by the sliding conveying force of 2 sets or 3 sets of the document conveying rollers. Therefore, the striking force of medium size documents and large size documents against the striking board will become large proportionately with the number of roller sets. At the time of sending the document backward and stopping it at the striking board, when the striking force of the document by each document conveying roller is excessive, the rear end of the document may be folded, wrinkles may be generated in the document, or the document may be set diagonally. Alternately, there may arise such troubles, where rear end of the document rides on the upper surface of the striking board or the document further passes above the striking board and returns to the paper feeder side. SUMMARY OF THE INVENTION In consideration of the above described points, the present invention aims at providing the document conveyance apparatus, where all documents of various sizes sent backward will uniformly contact with and certainly stop at the striking board, thereby permitting the document to stop at the correct position, by improvement of the document conveyance apparatus consisting of the above document holding sheet member and the document conveying rollers rotatably driven, in realizing reduction in thickness of the body frame and improvement in maintenance property as well. In order to accomplish the above purpose, in the document conveyance apparatus consisting of the document conveying rollers, which convey the document fed from the paper feeding means in normal direction on the document table of the copier and which also convey such document in reverse direction so as to contact against the striking board, and also of the document holding sheet member, which presses the document against the document table surface, the document conveyance apparatus of the present invention is characterized by having a number of document conveying rollers, in which a number of roller sets are provided to press against the above document table, arranged longitudinally along the document conveying direction, and also by providing a means of separating the conveying rollers, at least other than the document conveying roller set closest to the above striking board, from the document table, and is also characterized by having a construction where a spring clutch is built-in on the driving axis of conveying rollers and such driving axis is moved against the spring force, thereby separating the above document conveying rollers from the document table and driving thereof, by having a construction where a wire is connected to the driving axis of the conveying rollers, at least other than the document conveying roller set closest to the above striking board, such wire being moved correspondingly with the pressed driving of the above document holding sheet member, thereby driving the above document conveying rollers, being separated from the document table, and also by having a construction where the conveying rollers, at least other than the document conveying roller set closest to the above striking board, are attached to the elevating means having a freely rotatable supporting board, thereby separating the above document conveying rollers from the document table and driving thereof. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a sectional view of the document conveyance apparatus of the present invention, Fig. 2 an overall driving system diagram of this document conveyance apparatus, Fig. 3 a perspective view of the conveying roller driving system, Fig. 4 a perspective view showing layout of the white-colored sheet member and document conveying rollers, Fig. 5 a plan view of each part of conveying rollers in Embodiment 1, Fig. 6 a sectional view of the conveying driver in Embodiment 1, Fig. 7 a sectional view of the conveying roller in Embodiment 1, Fig. 8 and Fig. 10 sectional views of elevating means for conveying rollers in Embodiment 1, Fig. 9 and Fig. 11 side views showing elevating and rotating of conveying rollers in Embodiment 1, Fig. 12 a plan view of conveying mechanism in Embodiment 2 in the document conveyance apparatus of the present invention, Fig. 13 and Fig. 14 schematic illustrations which explain operating conditions of each conveying roller in Embodiment 2, Fig. 15 a plan view of the conveying roller driving system in Embodiment 3, Fig. 16 and Fig. 19 side views of the conveying roller driving system in Embodiment 3, Fig. 17 and Fig. 20 side views of the conveying roller elevating means in Embodiment 3, Fig. 18 a perspective view of the spring clutch, and Fig. 21 a plan view showing document sizes and conveying roller layout. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, embodiments of the present invention are explained according to the attached diagrams. Fig. 1 shows a sectional view of the document conveyance apparatus of the present invention, Fig. 2 an entire driving system of this document conveyance apparatus, Fig. 3 a perspective view of the conveying roller driving system, Fig. 4 a perspective view of white-colored sheet member and conveying rollers, and Fig. 5 a plan view showing driving mechanism of conveying rollers. In these diagrams, 10 is the copier proper, 11 the platen glass (document table), 12 the document rear end stopper (striking board), and the document conveyance apparatus 100 is mounted above the platen glass 11. Such document conveyance apparatus 100 is of shakable construction, being attached to the hinge above the copier proper 10, permitting opening or closing of the upper surface of platen glass 11. The above document conveyance apparatus 100 consists of the three principal parts, namely, paper feeder 200, conveyor 300 and paper discharger 400. On the upper portion of the document conveyance apparatus 100, there are provided the paper feeding tray, consisting of the movable paper feeding plate 102, which is foldable, and the fixed paper feeding plate 103, which is firmly attached to the housing proper 101, both of which are installed with an inclination. Document D can be loaded on such paper feeding tray in layers, and the end of document D can be inserted into the paper feeder 200. Further, on the above fixed paper feeding plate 103 there are provided the paper width control boards 104, movable in width direction, so as to control the lateral width in setting the document D. There is a cut-out notch near the middle on the downstream side in paper feeding direction in the above fixed paper feeding plate 103, and in such cut-out notch there is a movable guide plate, which is freely shakable in vertical direction from the upper surface of the fixed paper feeding plate 103. Such movable guide board 105 is connected to the solenoid, which is not shown in the diagram. On the other hand, the feeding lever 201 is shakably supported on top of the above movable guide board. In other words, the axis at one end of the feeding lever 201 is rotatably supported by axis on top of the paper feeder outlet 106 of the housing proper 101, and the other end descends due to own weight of the feeding lever 201, thereby pressing upper surface of the document D. At the time of feeding the document, the above movable guide board 105 is in ascending position, being stopped at slightly above the outer peripheral surface of the feeding roller 212. When document D is set on the movable paper feeding plate 102 and the fixed paper feeding plate 103 in the above position and document D is pushed out forward in paper feeding direction, the forward end of document D is pushed out along the upper surface of the above movable guide board and simultaneously pushes up the lower surface of the feeding lever 201, which is supported at the top and is hanging by its own weight. Then, document D stops by coming into contact with the outer peripheral surface of the double-feeding prevention roller 213, which is to be described later, and also with the rib of the housing proper 101. Fig. 1 is a sectional view showing this document setting condition. When the above solenoid is supplied with electricity by the starting signal of paper feeding, the movable guide board 105 is shaked and its forward end falls and starts descending from the upper surface of the above fixed paper feeding plate 103. Next, at the left side of the document conveyance apparatus 100 (in Fig. 1), the paper feeder 200 installed on the feeding downstream side of the above paper feeding tray is provided with the sending means (No. 1 paper feeding means) for sending a bundle of document D inserted from the paper feeding tray and, further, for sending such document, by separating each sheet from the lowest layer, and also with the No. 2 paper feeding means of feeding the document D onto the platen glass 11 of the copier proper 10. This sending means consists of the sending roller (No. 1 paper feeding roller) 212, which is rotatably inserted in the center of No. 1 driving axis 210 and is driven by No. 2 driving axis 211, and the double-feeding prevention roller 213, which is axially supported by the double-feeding prevention roller attachment board 214, installed in diagonally upper direction of such sending roller 212. Fig. 2 is the driving system diagram for the entire document conveyance apparatus. Driving axis of the main motor 215 rotates the above No. 2 driving axis 211 via gears 216 and 217, timing pulleys 218 and 219 and timing belt 220, gear 221 which is coaxial with the timing pulley 219 and gear 222 which is integral with No. 2 driving axis 211. At one end of such No. 2 driving axis 211 there is provided gear 224 which has one-direction clutch 223 built therein. This gear 224 engages with gear 225 which is integral with the sending roller 212, rotatably inserted in the above No. 1 driving axis 210. That is to say, with respect to the main motor 215 which makes normal and reverse rotation, while the sending roller 212 rotatably inserted into No. 1 driving axis 210 rotates by having power transmitted from No. 2 driving axis 211 only when the main motor 215 is making reverse rotation, it rotates freely with no power being transmitted when the main motor 215 is making normal rotation. On the other hand, on the axis of No. 2 driving axis 211, on both sides of the above sending roller 212, No. 2 paper feeding rollers 226, 226 are fixed on the axis, thereby rotating integrally with the driving axis. Further, close to the axis tip of the above No. 1 driving axis 210, there are respectively attached two gears 227 and 228, which have one-direction clutch built therein, and gear 229, which is fixed on the axis. On the other hand, at the axis tip of the above No. 2 driving axis 211, gear 230 is fixed on the axis, and such gear 230 engages with gear 227 at the axis tip of the above No. 1 driving axis 210. In this manner, No. 1 driving axis 210 and No. 2 paper feeding rollers 226, 226 integral thereto make a fixed rotation always in the direction of paper feeding, with respect to normal and reverse rotation of the main motor 215. Gear 229 fixed on the axis of the above No. 1 driving axis 210 is transmitting power to No. 3 driving axis (torque limiter axis) 234 having gear 233 fixed at one tip thereof, via idler gear 232. At another tip of No. 3 driving axis 234 there is provided gear 236 having torque limiter 235. Such gear 236 engages with gear 238 which is integral with the above double-feeding prevention roller 213 via idler gear 237. Double-feeding prevention roller 213 forms a nip, being pressure contacted to the above sending roller 212 at a prescribed pressure. As described above, the above No. 1 driving axis 210 makes rotation in the fixed direction, regardless of the normal or reverse rotation of the main motor 215, and it is also possible to have rotation in the fixed direction for the double-feeding prevention roller 213 coupled thereto via gears. During the document feeding through use of the above sending roller 212 and double-feeding prevention roller 213, No. 2 paper feeding rollers 226, 226 fixed on the axis of No. 1 driving axis 210, which rotatably support the sending roller 212 also rotate at the same speed and in the same direction as the sending roller 212, thereby performing a supplementary role of U-turn feeding of document D. No. 2 paper feeding means in the paper feeding means 200 consists of two No. 2 paper feeding rollers 226, 226 fixed on both sides of the above sending roller 212, rotatably inserted in the above No. 1 driving axis 210, and the driven roller 240 pressure contacted on the lower side of such rollers 226, 226, capable of being rotatably driven by such rollers. These No. 2 paper feeding rollers 226, 226 can be driven independently from the sending roller 212, and, further, when the sending roller 212 rotates, they will rotate in the same direction, thereby not interfering with the sending of document D. There is provided a document detection sensor 241 on the conveyance path in the downstream of feeding from the nip position between the above sending roller 212 and double-feeding prevention roller 213 and close to the pressure contacting position of the above driven roller 240. Such document detection sensor 241 is so arranged to be turned ON when forward end of one document, separated and sent at the nip position, among the above bundle of documents passes, to be turned and OFF when the rear end thereof passes. When the above document detection sensor 241 detects forward end of a document, after a definite time from issuance of such detection signal, solenoid is made ON and each member of the link mechanism is actuated, thereby descending the movable guide board 105. Further, simultaneously with the above, while the main motor 215 will shift from reverse rotation to normal rotation, No. 1 driving axis 210 at this time will still continue rotation in the same direction, and No. 2 paper feeding roller 226, fixed on the axis of such axis 210, will also continue rotating in the same direction, via gear 230 of No. 2 driving axis 211, idler gear 232, gear 227 which has one-direction clutch built therein (but rotation is not transmitted to the gear 228 which has the above one-direction clutch built therein). However, with shifting of the main motor 215 to normal rotation, No. 2 driving axis 211 will also shift from reverse rotation to normal rotation, but gear 224 will become free rotation by the one-direction clutch 223 provided at the axis tip of such No. 2 driving axis 211, and rotation will not be transmitted to any of gear 225 engaging thereto and sending roller 212 integral with gear 225. Here, when forward end of document D is head with pressure between the above No. 2 paper feeding roller 226 and the driven roller 240, document D which is tightly wound between the sending roller 212, which makes free rotation, and No. 2 paper feeding roller 226, which makes normal rotation, will rotate the sending roller 212 in the direction of paper feeding. Further, double-feeding prevention roller 213 acts to prevent double-feeding of the document in the second sheet and thereafter and to return thereof by continuously making normal rotation, since No. 1 driving axis 210 maintains normal rotation. Additionally, No. 2 paper feeding roller 226 will continue its rotation thereafter and will continuously feed the separated one sheet of document D to conveyor 300. Conveyor 300 is for the purpose of conveying document D on platen glass 11, and is provided with white-colored sheet member 304 and document conveying rollers 301, 302 and 303 as principal elements. White-colored sheet member 304 (hereinafter called the sheet member) is for the purpose of pressuring document D at the time of exposure and is made of plastic material (PET: polyethylene terephthalate in the present embodiment) which is rich in solid lubrication property, and this covers the entire upper surface of platen glass. Left end 304a of the above sheet member 304 on the side of paper feeder 200 is attachably fixed in the bend of sheet stopping board 361. Protruded both ends of such sheet stopping board 361 are fixed to the frame proper of paper feeder 200 with screws. On the other hand, right end 304b of the above sheet member 304 on the side of paper discharger 400, after make a U-turn, is attachably fixed in the bend of the other sheet stopping board 362. Center of such sheet stopping board 362 is connected to the fixed portion of conveyor 300 with pressure of a coil spring, which is not shown in the diagram. Further, at appropriate places along the center line of sheet member 304, there are provided perforated holes 305, 306 and 307, through which tips of document conveying rollers 301, 302 and 303 are made to protrude. Document conveying rollers 301, 302 and 303 are for the purpose of conveying document D on platen glass 11, and are provided to correspond with each perforated holes 305, 306 and 307 on the back surface side of sheet member 304, so as to convey document D by frictional force under pressure while rotating, through perforated holes 305, 306 and 307. Surface of such rollers 301, 302 and 303 are covered by an elastic material having large frictional force (for example, foamed material of EPDM rubber ethylene-propylene rubber or plastics), and its tip contacts with the surface of platen glass through perforated holes 305, 306 and 307. Additionally, document conveying rollers 301, 302 and 303 can make both normal and reverse rotation, so as to permit fine adjustment for final position of document D at the time of exposure. Sheet member pressuring means 360 is for the purpose of improving exposure conditions by closely contacting the sheet member 304 onto platen glass 11 at the time of exposing the document and also of making smooth conveyance of document by raising the sheet member from the surface of platen glass 11 at the time of conveying the document. Unless pressuring force is applied on sheet member 304, it is so arranged that such sheet member 304 is raised upward. Such pressuring means 360 consists of pressuring board 360A (swing back board) and pressuring driving axis 360B. Pressuring board 360A is co-axial with the sheet member 304, so as to permit pressuring of the above sheet member 304 against the striking board with uniform force, and is of elastic member, having a protruding curved surface on the contacting side with sheet member 304. End of the pressuring driving axis 360B is connected to the main motor 215 via a series of gears, from which driving is transmitted to the axis. (Refer to swing back board "E" in Fig. 2.) There is provided a torque limiter at the end of the above pressuring driving axis 360B, and when the above pressuring board 360A contacts with the striking board, it will act to maintain the contacting condition and also to eliminate undue load. The above main motor 215 drives the above paper feeder 200 and conveyor 300 simultaneously. That is to say, gear 216 which is integral with main motor 215 is connected to the conveying driver 310 via a series of gears, thereby rotatably driving the driving axis (station axis) 311. Fig. 6 is a sectional view of the above conveying driver 310. The above driving axis 311 is supported rotatably at its axis by bearings 312 and 313 close to both ends of the axis as well as by the attachment boards 314 and 315, which fix such bearings 312 and 313. Further, at one end of such driving axis 311 there is fixed the gear 316, and close to the other end there is fixed the pulley 317. Such gear 316 engages with freely-rotatable gear 320, having a small diameter, on the idler axis 319 fixed to the attachment board 318. Such small-diameter gear 320 is integral with large-diameter gear 321, and such gear 321 engages with gear 216, which is integral with driving axis of the above main motor 215. In this manner, the driving rotational force of main motor 215 is transmitted via a series of gears 216, 321, 320 and 316, thereby rotating the driving axis 311. Timing pulley 317 installed at end of driving axis 311 has geared pulley at two places on both ends, and they are respectively rotatable for winding the timing belts 322, 323. On the feeding upstream side of the above driving conveyor 310, there is placed No. 1 conveying roller 330 via timing belt 322. Further, on the feeding downstream side, there is placed No. 2 conveying roller 340 via timing belt 323, and on the farther feeding downstream side, there is placed No. 3 conveying roller 350 via timing belt 324, respectively. In the center of rotating axis 331 of No. 1 conveying roller 330, there is timing pulley 332 integrally fixed on the axis. On both sides of such timing pulley 332, there are fixed document conveying rollers 301, 301. At both ends of such rotating axis 301, there are fitted bearings 333, 333 made of an iron-copper group sintered alloy. Such bearings 333, 333 are respectively inserted into the longitudinal hole of the forward and rear conveying roller attachment boards 334, 334, and their rotation will be stopped by the notch. Rotating axis 301 of the above document conveying roller 301 is inserted into the above attachment boards 334, 334 together with bearings 333, 333. Bearings 333, 333 at both ends of rotating axis 301 will be spring energized by torsion springs 335, 335, thereby pressuring the outer peripheral surface of document conveying roller 301 against the surface of platen glass 11. No. 1 conveying roller 330 as constructed above is pressured against platen glass 11, and will simultaneously have driving transmitted thereto by the timing belt 322, which is wound on the timing pulleys 317, 331. Fig. 7 is a sectional view of No. 2 conveying roller 340. Document conveying roller 302 of No. 2 conveying roller 340 will be similarly spring energized by torsion springs 345, 345, thereby pressuring the outer peripheral surface of document conveying roller 302 against the surface of platen glass 11. Further, by rotation of the timing belt 323 the timing pulley 342 rotates, thereby transmitting such rotation. No. 3 conveying roller 350 consists of members common with those for No. 2 conveying roller 340. That is to say, driving force of the above timing pulley 342 and timing belt 324 is received with timing pulley 352, and it rotates integrally with such timing pulley 352. Tensioned spring force will pressure the conveying roller, in the same manner as before, thereby pressuring against the platen glass 11. Hereinafter, explanations will be made in using No. 2 conveying roller 340 as representative example. In the above rotating axis 341, there are timing pulley 342, document conveying rollers 302, 302 and collars 346, 346 are fixed with knock pin or the like etc. Document conveying roller 302 consists of bush member 3022 fixed to rotating axis 341 with pin and elastic member 3021 covering the outer periphery of such bush member 3022. Between the collar 346, fixed to the above rotating axis 341, and the timing pulley 342, spring clutch member 347 is inserted into the rotating axis 341, permitting free movement in axial direction as well as rotation. Between receptacle of such clutch member 347 and timing pulley 342, there is torsion spring 348 placed in compressed condition, thereby pressuring clutch member 347 against collar 346. Fig. 8 shows a sectional view of elevating driving means of conveying rollers 302 and 303 at the time of normal sending of document, and Fig. 9 a side view of each position and rotational driving of conveying rollers 301, 302 and 303 in conveyor 300 at the time of normal sending of document. When rotating axis 341 is rotated in counterclockwise direction, collar 346 fixed to such rotating axis 341 will rotate as well, and the clutch member 347 pressure contacted by torsion spring 348 will rotate simultaneously by friction with collar 346. When protrusion 347a of clutch member 347 comes into contact with the stopper surface 349a, rotation of clutch member 347 will stop and slide idly on the contact surface with collar 346. In this condition, bearings 343, 343 which support both ends of rotating axis 341 will descend toward platen glass 11 along inner wall of the longitudinal holes of the above conveying roller attachment boards 344, 344, and will stop descending by coming into contact with the surface of platen glass 11. At the same time, document conveying roller 303 in No. 3 conveying roller 350 will also descend and come into contact with platen glass 11. In a condition where the above conveying rollers 302, 303 have descended, such rollers will pressure document on platen glass 11 and will convey the document in normal direction by rotatable driving. By reverse driving of main motor 215, document D send toward platen glass 11 from paper feeder 200 will slide above platen glass 11 by conveying rollers 301, 302 and 303 in conveyor 300, and rear end of document D passes the stopper for rear end of document (striking board) 12. After the rear end of document D, during the document feeding, passes the above document detection sensor 241 shown in Fig. 1 and the rear end detection signal is issued, the prescribed pulse corresponding to document size is counted. During this document normal feeding, each member in the conveying roller driver will rotate in the direction of arrow mark shown in Fig. 8 and Fig. 9 by the driving force of main motor 215, and protrusions 347a and 357a in spring clutches 347 and 357 will rotate in counterclockwise direction, and will stop by coming into contact with stoppers 349a, 359a. Conveying roller driver will continue rotating in the above direction of arrow mark by driving force of main motor 215. While clutch member 347 will stop, the rotating axis 341 and document conveying roller 302 integral therewith will continue rotation and driving. Document conveying roller 303 in No. 3 conveying roller 350 will similarly pressure against platen glass 11 and will rotate and drive in counterclockwise direction. Further, since only No. 1 conveying roller 330 does not have spring clutch, it will always rotate and drive in pressuring against platen glass 11. In other words, during the reverse driving of the above main motor 215, document conveying rollers 301, 302 and 303 will all pressure against platen glass 11 and rotate and drive in counterclockwise direction, thereby normally conveying document D in the direction of arrow mark. When the above pulse number is counted up, (Rear end of document D has already passed the striking board 12, and is advancing on the platen glass 11.) main motor 215 is switched from reverse rotation to normal rotation, and conveying rollers 301, 302 and 303 make reverse rotation, thereby conveying document D in reverse direction. By having the rear end of document coming into contact with the striking board 12, document D will be set at the prescribed position on platen glass 11. Fig. 10 is a sectional view of elevating driving means of conveying rollers 302 and 303 at the time of reverse sending of document, and Fig. 11 a side view of each position and rotational driving of conveying rollers 301, 302 and 303 in conveyor 300 in reverse sending condition of document. By switching the above main motor 215 to normal rotation, each of document conveying roller 301, 302 and 303 in each of conveying rollers 330, 340 and 350 will all at once rotate in the direction of arrow mark (rotation in clockwise direction) as shown in Fig. 10 and Fig. 11. Here, while clutch member 347 of No. 2 conveying roller 340 will initially rotate in clockwise direction together with rotating axis 341, being pressured by torsion spring 348, when its protrusion 347a comes into contact with stopper 349b, the rotation will stop, by having the movement obstructed, and it will rotate idly by having relative friction with collar 346 which is fixed to the rotating axis 341, which rotates being driven. While rotating axis 341 will continue driving rotation, due to restrictions by protrusion 347a of clutch member 347 and stopper 349b, bearings 343, 343 supporting both ends of rotating axis 341 will be pushed upward, in resisting the pressing force of torsion springs 345, 345, along inner wall of longitudinal hole of the conveying roller attachment boards 344, 344, and conveying rollers 302, 302 will separate from the surface of platen glass 11, thereby forming the gap S. Simultaneously with the above, conveying roller 303 will also be pushed upward, and will be separated from the surface of platen glass 11. However, since conveying roller 301 of No. 1 conveying roller 330 is always rotationally driven in pressing against platen glass 11, conveying rollers 302 and 303 will retreat upward and conveyance under pressure will be made only by conveying roller 301, at the time of sending document in reverse direction. Thereafter, when the prescribed pulse count is made, rear end of document D will come into contact with the striking board 12, conveyance is stopped once, sheet member 304 presses document D against platen glass 11, then exposure scanning of document and image forming process will be started continuously in copier body 10. After completing exposure scanning, main motor 215 is again switched to reverse rotation, where each rotating axis 331, 341 and 351 will make counterclockwise rotation as shown in Fig. 8 and Fig. 9, and document conveying rollers 302 and 303 will make driving rotation while pressing against the surface of platen glass 11. By pressure contacted rotation of each of the above conveying rollers 301, 302 and 303, the document will pass above platen glass 11 and be discharged being pressure held by paper discharging roller 401 of paper discharger 400 and pinch rollers 402 and 403, and be placed above the discharged paper tray 406, which is placed outside. When the front end or the rear end of document D is detected by paper discharging sensor 404 provided in the conveying path of the above paper discharger 400, the paper feeding action for 2nd and subsequent sheet of document will be repeated in the same manner as above. Fig. 12 is a plan view of the conveyor of document conveyance apparatus under Embodiment 2 of the present invention, and Fig. 13 and Fig. 14 are schematic diagrams in explaining elevating of document conveying rollers. Further, in these diagrams, portions having the same functions as those in the above embodiment will be denoted by the same number. Further, explanations will be made on points which are different from the above embodiment. Conveyor 300 consists of the conveying driver 310 which transmit driving force of main motor 215 to document conveying rollers 301, 302 and 303, No. 1 conveying roller 330 which supports document conveying roller 301 close to the striking board 12, No. 2 conveying roller 340 which supports the middle document conveying 302, No. 3 conveying roller 350 which supports document conveying roller 303 close to the paper discharger 400, and the roller elevating means 370 which acts to elevate the above document conveying rollers 302 and 303 by wire. Here, the conveying driver 310 and No. 1 conveying roller 330 have almost identical construction with the above embodiment, and explanations on the construction and functions concerning No. 2 and No. 3 conveying rollers 340 and 350 are to be omitted. V-shaped groove 3170 is formed in the central drum of timing pulley 317 in conveying driver 310, to which wire 371, to be described later, will be hung. Further, V-shaped grooves 3420 and 3520 of the same form as above are respectively formed in each central drum of timing pulleys 3420 and 3520 in No. 2 and No. 3 conveying rollers 340 and 350. Flap board 372 is fixed to the pressure driving axis 360B of the above sheet pressing means 360, on the side close to paper feeder 200, and one end of wire 371 is fixed at the tip of such flap board 372. Close to document conveying roller 303, there is the terminal fixing member 373 attached to the above housing proper 101, to which the other end of wire 371 is fixed, thereby permitting adjustment of wire hanging. Between the above flap board 372 and the terminal fixing member 373, there are provided guide roller 374 and tension roller 375, on both of which V-shaped grooves 3740 and 3750 of the same form as above are formed. Guide roller 374 is freely rotatable, being supported by the supporting board 3741 and guide pin 3742. Tension roller 375 is supported by supporting board 3751, shaking lever 3752 and pin 3753, and is freely movable and rotatable to flip by the tension of spring 3754. The above wire 371 is held by the flip board 372 at its left end and is held by the terminal fixing member 373 at its right end, and is suspendedly hung, being pressured, in its middle portion, by V-shaped groove 3740 of guide roller 374, V-shaped groove 3170 on the axis of conveying driver 310, V-shaped groove 3420 on the same axis as document conveying roller 302, V-shaped groove 3750 of tension pulley 375 and V-shaped groove 3520 on the same axis as document conveying roller 303. Fig. 13 is a schematic diagram showing actions of the conveyor 300, when document D is normally conveyed in the direction of arrow mark. At the time of this normal conveying, the document conveying roller 301, 302 and 303 are driven and rotated in counterclockwise direction. Moreover, at this time the pressure driving axis 360B of sheet pressuring means 360 will also be driven in counterclockwise direction, and the pressure board (swing back board) 360A fixed to such pressure driving axis 360B will move to the upper position shown with a solid line, thereby facilitating document conveyance by not pressuring sheet member 304 and making it free. By this rotation of pressure driving axis 360B in counterclockwise direction, the flap board 372 fixed to such axis will also rotate in counterclockwise direction, thereby loosening the tension in wire 371. Therefore, document conveying rollers 302 and 303, forming one body with V-shaped grooves 3420 and 3520, which are wound with such wire 371, will descend being spring energized, thereby pressuring the surface of platen glass 11. Further, wire 371 is so laid that its tension or relaxation can be absorbed by upward movement of tension roller 375, being energized by spring. Driving rotation by the above document conveying rollers 301, 302 and 303 and pressuring against platen glass 11 will normally convey document D in the direction of arrow mark, with the joint action of releasing pressure by sheet member 304. When conveying document D in reverse direction toward the striking board 12, document conveying rollers 301, 302 and 303 are made to rotate in clockwise direction by switching driving axis 311 in reverse, and simultaneously pressure driving axis 360B will rotate in counterclockwise direction and flap board 372 fixed to such axis will also shake in counterclockwise direction, thereby lowering the wire 371. By the above actions, wire 371 will raise conveying rollers 302 and 303 upward, in resisting the tensioned spring force, via guide roller 374 and V-shaped groove 3170 on driving shaft, thereby forming gap S between upper surface of platen glass 11 and lower peripheral surface of document conveying rollers 302 and 303. Simultaneously with the above, pressuring board 360A will also descend and also press against the striking board 12 via sheet member 304, thereby shutting the space above the striking board 12. In this condition, since document conveying rollers 302 and 303 have retreated in the upper position, document D will be conveyed reversely in the direction of arrow mark in Fig. 14 on platen glass 11 only by driving rotation of document conveying roller 301 and will come in contact with the end surface of the striking board 12, which is in sealed condition, thereby making determination of document position. Further, while the above wire 371 is respectively wound in the central portion of No. 2 document conveying rollers 302, 302 and the central portion of No. 3 document conveying rollers 303, 303, the present invention is not necessarily restricted to this point. By laying a total of 2 wires, one wire respectively, close to both ends of rotating axis 341 which fixes No. 2 document conveying rollers 302, 302, and also close to both ends of rotating axis 351 which fixes No. 3 document conveying rollers 303, 303, elevating of each roller can be made more certain. Fig. 15 is a plan view of the conveyor of document conveyance apparatus under Embodiment 3 of the present invention, Fig. 16, Fig. 17, Fig. 19 and Fig. 20 are schematic diagrams for explaining elevating of document conveying roller, and Fig. 18 a perspective view of spring clutch. Further, in these figures portions having the same functions as those in Embodiments 1 and 2 will be denoted by the same number. Further, points different from Embodiments 1 and 2 will be explained. Driving rotational force of main motor 215 is transmitted via a series of gears 216, 321, 320 and 316 and rotates the driving axis 311, in the same manner as in the above two embodiments. Timing pulley 317 fixed at axis end of driving axis 311 has geared pulley at 2 places in both ends, which are rotatable by winding timing belts 322 and 323 respectively. On the feeding upstream side of driving conveyor 310 there is place No. 1 conveying roller 330, not shown in the diagram, via timing belt 322. Further, on the feeding downstream side there is placed No. 2 conveying roller 340, via timing belt 323, and on further feeding down stream side there is placed No. 3 conveying roller 350, via timing belt 324, respectively. Since the above conveying rollers 330, 340 and 350 are all consisted of common members, hereinafter explanations will be made on the conveying roller 340 in representing the rest. At the center of rotating axis 302a, which is integral with document conveying roller 302, there is fixed the timing pulley 341. Further, at both ends of such rotating axis 302a, there are insertedly fitted bearings 342A and 342B of iron and copper group sintered alloy. Such bearings 342A and 342B are respectively inserted in the longitudinal hole of front and rear conveying roller attachment board 343 respectively, and their rotation is stopped at the notch. Rotating axis 302a of the above document conveying roller 302 is inserted in the above attachment board 343 together with bearings 342A and 342B. Bearings 342A and 342B will contact the outer periphery of document conveying roller 302 with surface of platen glass 11 under pressure, being spring energized. No. 1 conveying roller 330, not shown in diagram, which is constructed in the same manner as No. 2 conveying roller, will have driving transmitted thereto by the timing belt 322, which is wound on timing pulleys 317, 331, while being pressed against platen glass 11. Document conveying roller 302 of No. 2 conveying roller 340, while being spring energized in the similar manner, will have rotation transmitted thereto with rotation of the timing pulley 341, by rotation of the timing belt 323. Here, 342A and 342B are bearings which rotatably support both ends of conveying roller 303 and which can move in vertical direction, being inserted in the long hole of attachment board 343, and they are pressured against platen glass 11 by torsion spring 344. Document conveying roller 303 of No. 3 conveying roller 350 receives driving force of the above timing pulley 341 and timing belt 324 with timing pulley 351, and rotates integrally with such timing pulley 351. Spring energized force will pressure the conveying roller, in the same manner as before, thereby pressing against the platen glass 11. Here, 352A and 352B are bearings which rotatably support both ends of conveying roller 302 and which can move in vertical direction, being inserted in the long hole of attachment board 353, and they are pressured against platen glass 11 by torsion spring 354. Fig. 16 is a side view of rotational driving means of conveying rollers 302 and 303, showing document conveying condition and Fig. 17 a side view of elevating driving means of such conveying rollers 302 and 303. On the axis of the above gears 320 and 321 there is timing pulley 361 integrally formed therewith, which is wound to the other timing pulley 363 by timing belt 362. Such timing pulley 363 forms one body with gear 364 and rotatable around the supporting axis placed on the supporting base board 366. The above gear 364 engages with gear 3671 in spring clutch 367 provided at one end of the cam axis 371, to be described later. Such cam axis 371 is rotatably supported by bearing 368 fixed to the above supporting base board 366 and by bearings 372A and 372B provided in supporting board 374 of the conveying roller elevating means 370, to be described later. Fig. 18 is a perspective view of spring clutch 367. In the diagram, spring clutch 367 consists of hub 3672 fixed to cam axis 371, the above gear 3671, which is freely rotatable, being integral with sliding bearing which fit into cam axis 371, coil spring 3674, which is freely tightened or loosened, being wound to each drum of such gear 3671 and hub 3672, and collar 3675 which ties one end of such coil spring and covers coil spring. Protrusion 3672A is formed on a part of the periphery of the above hub 3672, and rotation of hub 3672 will stop, when such protrusion 3672A comes into contact with one tongue 369A of the stopper 369, fixed to supporting base board 366. Further, there is formed protrusion 3675A on a part of the periphery of collar 3675, and rotation of collar 3675 will stop, when such protrusion 3675A comes into contact with the other tongue 369B of the above stopper 369. On the above cam axis 371, there are eccentric cams 373A and 373B fixed thereon. On both front and rear side walls of the above attachment board, there are studded 4 supporting axes 375A, 375B, 375C and 375D, on each of such supporting axes there are wound coil springs 376A, 376B, 376C and 376D. Further, on each such supporting axis there are respectively inserted flap levers 377A, 377B, 377C and 377D. The above flap levers 377A and 377B are respectively spring energized by coil springs 376A and 376B, thereby shaking in counterclockwise direction, centering around the above supporting axes 375A, 375B, raising right end (refer to Fig. 17) of each flap lever 377A and 377B and contacting with eccentric cams 373A, 373B under pressure. On the other hand, left end of flap levers 377A and 377B descends, and conveying roller 302 of No. 2 conveying roller 340 descends along the long hole of attachment board 343, by tensioned spring force of torsion spring 344 as well as its own weight, and comes into contact with the upper surface of platen glass 11, pressuring thereon. Simultaneously with the above, the other flap levers 377C and 377D are respectively energized by coil springs 376C and 376D, thereby shaking in counterclockwise direction, centering about the above supporting axes 375A and 375B, raising left end (refer to Fig. 8) of each shaking levers 377C and 377D and contacting with the eccentric cams 373C, 373D under pressure. On the other hand, right end of such flap levers 377C and 377D descends, and conveying roller 303 of No. 3 conveying roller 350 descends along the long hole of attachment board 353, by tensioned spring force of torsion spring 354 as well as its own weight, and comes into contact with the upper surface of platen glass 11, pressuring thereon. When conveying a large-sized document (for example, A3 size, B4 size, etc.), the document on platen glass 11 is conveyed by driving rotation under pressure, in conditions where the above conveying rollers 302 and 303 are in descent state. A large-sized document D fed toward platen glass 11 from paper feeder 200, by reverse driving of main motor 215, will slide on the platen glass 11 by conveying rollers 301, 302 and 303 of conveyor 300 shown in Fig. 1, and the rear end of document D will pass over the document end stopper (the striking board) 12. After the rear end of document D, which is being fed, passes the above document detection sensor 241 and the rear end detection signal is issued, prescribed pulse corresponding to document size will be counted. During this normal sending of document, each member of conveying roller driver rotates in the direction of arrow mark shown in Fig. 16 by driving force of the main motor 215, hub 3675 of spring clutch 367 rotates in counterclockwise direction, and protrusion 3675A stops by coming into contact with tongue 369B of stopper 369. This hub 3675 of spring clutch 367 rotates as one body with cam axis 371, being pin connected thereto, and cams 373A and 373B will stop, when reaching the upper dead point shown in Fig. 17. Conveying roller driver continues to rotate in the direction of the above arrow mark by driving force of main motor 215. While gear 3671 of spring clutch 367 is also rotating continuously, depending on the degree of loosening in coil spring 3674, which is built in spring clutch 367, it will rotate idly with sliding bearing 3673, thus the driving force will not be transmitted to cam shaft 371. When this pulse number is counted up, the main motor 215 will have its rotation changed from reverse to normal, and conveying rollers 301, 302 and 303 will rotate in reverse direction and make the rear end of document D to contact with the striking board 12, thereby placing document D in the prescribed position on the platen glass 11. Fig. 19 is a side view of rotational driving means of conveyor 300 in document reverse sending condition, and Fig. 20 a side view of elevating driving means of conveying rollers 302 and 303 at the time of document reverse sending. By normal rotation of the above main motor 215, each member of conveying roller driver will rotate in the direction of arrow mark shown in Fig. 19, and gear 3671 of spring clutch 367 rotates in clockwise direction, thereby integrally rotating hub 3672, which is spring connected to such gear via coil spring 3674. Protrusion 3672A of hub 3672 rotates in reverse direction and comes into contact with tongue 369A of the above stopper 369, and hub 3672 stops. By the above action, cam axis 371 integral with hub 3672 will also stop after rotating in reverse direction, and cams 373A and 373B come to the lower dead point shown in Fig. 20. Further, the above gear 3671 continues to rotate in reverse direction by normal driving force of the above main motor 215, even after hub 3672 stopped, depending on the slackening condition of coil spring 3674. Due to rotational movement of the above cams 373A and 373B to the lower dead point, flap levers 377A and 377B will flip, centering around supporting axes 375A and 375B respectively, being pressured by such cams 373A and 373B, and ends of flap levers 377A and 377B will pressure against and push up bearings 342A and 342B, inserted into both ends of conveying roller 302, thereby separating conveying roller 302 from the surface of platen glass 11. Simultaneously with the above, flap levers 377C and 377D will also be flaped by the above cams 373A, 373B, and thereby separating conveying roller 303 from the surface of platen glass 11. However, since conveying roller 301 of No. 1 conveying roller 330 is always driven rotatably, pressuring against platen glass 11, it is pressure conveyed only by conveying roller 301 at the time of conveying document, regardless of document size. Thereafter, after the prescribed pulse count, the sheet member 304 will pressure contact document D to platen glass 11, and exposure scanning and image forming process of the document will be started consecutively within the copier proper 10. Document D, for which exposure scanning has been completed, passes above platen glass 11 by pressured rotation of conveying rollers 301, 302, and 303, is discharged being held with pressure by paper discharging roller 401 of paper discharger 400 and pinch rollers 402, 403, and is placed above the paper discharging plate 406, which is located outside. When the front end or rear end of document D is detected by paper discharging sensor 404, placed in the conveying path of the above paper discharger 400, paper feeding actions for second and subsequent sheets will be repeated in the same manner as described above. As described in the foregoing, the document conveyance apparatus of the present invention is a document conveyance apparatus of roller conveying type, which has realized reduction in equipment thickness and improvement in maintenance quality, in each of Embodiments 1, 2 and 3. Particularly, when document is sent in reverse direction toward the striking board, document is conveyed by reverse driving by at least one set of conveying rollers closest to the striking board, among a number of conveying rollers. Since other rollers are separated from the surface of platen glass, the document being sent in reverse direction will be sent smoothly in reverse direction always by a constant conveying force, regardless of the document size. By such arrangement, the pressure contacting force for stopping the document, being sent in reverse direction, against the striking board will become nearly constant, thereby eliminating troubles such as damages on document, unsatisfactory determination of document position, etc. Further, elevating means of conveying rollers does not require an exclusive power source and construction of conveyor is simple, thereby exhibiting excellent effects in realizing low cost and improvement of reliability.

Claims: A document conveyance apparatus (100) for conveying a document (D) to a predetermined position on a platen glass (11) of a copying apparatus (10), comprising: a document feed means (200) for feeding said document (D) from outside of said document conveyance apparatus (100); a conveyance roller means (310, 330), located on said platen glass (11), for conveying said document (D) from said document feed means (200) onto said platen glass (11) by rotating in the forward direction and for subsequently bringing the trailing edge of said document (D) into contact with an edge setting member (12), located adjacent to said platen glass (11), by rotating in the reverse direction so that said document (D) is set at said predetermined position on said platen glass (11); characterized in that said document conveyance apparatus (100) further comprises: a retractable conveyance roller means (340, 350), located on said platen glass (11), for conveying said document (D) onto said platen glass (11) by cooperating with said conveyance roller means (310, 330) when said document (D) is longer than a predetermined size; and a roller retraction means (370) for retracting said retractable conveyance roller means (340, 350) from said platen glass (11) so that said retractable conveyance roller means (340, 350) does not convey said document (D); wherein said retractable conveyance roller means (340, 350) is capable of being retracted from said platen glass (11) by said roller retraction means (370) while said conveyance roller means (310, 330) is rotating in the reverse direction to bring said document (D) into contact with said edge setting member (12). The apparatus of claim 1, wherein said roller retraction means (370) comprises a spring clutch member (347) for retracting said retractable conveyance roller means (340, 350) when said conveyance roller means (310, 330) rotates in the reverse direction. The apparatus of claim 1, wherein said roller retraction means (370) comprises a wire member (371) for retracting said retractable conveyance roller means (340, 350). The apparatus of claim 1, wherein said roller retraction means (370) comprises an arm member (377A, 377B, 377C, 377D) and a cam member (371, 373A, 373B) for pivotally moving the arm member (377A, 377B, 377C, 377D), said retractable conveyance roller means (340, 350) being rotatably positioned on said arm member (377A, 377B, 377C, 377D) and retractable from said platen (11) in response to movement of said cam member (371, 373A, 373B).

Inventors: KAWANO MINORU C O KONICA CORPO, MIURA KAZUNOBU C O KONICA CORP, MURATA KAZUSHIGE C O KONICA CO, NAGOSHI MITSURU C O KONICA COR, KAWANO, MINORU C/O KONICA CORPORATION, MIURA, KAZUNOBU C/O KONICA CORPORATION, MURATA, KAZUSHIGE C/O KONICA CORPORATION, NAGOSHI, MITSURU C/O KONICA CORPORATION
Applicants: KONISHIROKU PHOTO IND, KONICA CORPORATION
Application year: 1989
Main classification: B65H3
IPC codes: G03B27, B65H5, G03G15