Device for feeding a recordable paper in an ink jet printer

Abstract: An ink jet printer (100) is described. It is designed such that a record paper stacking plate (221) is moved upward by reciprocating movement of a print-head carriage (410), to be positioned at a paper feeding position at an initial printing operation. As a result, it is possible to save time spent in record paper feeds. Further, the time taken to pick up the record paper can be reduced by using a CR motor having a large torque.

Description: BACKGROUND TO THE INVENTION The present invention relates to a device for feeding record sheets in, for example, an ink jet printer. In a conventional ink jet printer, record paper stacked on a stacking and feeding plate is fed by a pick up roller between a friction roller and a feed roller. The pick up roller is rotated by the drive from an electric motor. When the record paper reaches a base frame, a carriage is reciprocated along a guide shaft and a print-head in the carriage prints data on the record paper. Then, the paper on which the data are printed is discharged from the printer by a discharging roller. The device for feeding the record paper includes a stacking plate that carries the record sheets and a pick up roller for picking up a sheet of paper on the stacking plate and feeding the paper to the feed roller. The device also has a feeding spring between a main frame and the stacking plate. Such a device is known from for instance US-A-5 672 019. Since a LF (line feed) electric motor which is used as a power source has a low speed, it is difficult to drive the pick up roller and different driven rollers. As a result, there is a problem in that it takes a long time to feed the record paper and print the data on the record paper. SUMMARY OF THE INVENTION The present invention is designed to overcome this problem. Accordingly, the present invention provides an image-forming apparatus (such as an ink jet printer) comprising: a reciprocating print-head; a stacking plate for supporting a stack of record sheets; a feed roller for feeding a record sheet stacked on the plate to a printing region of the print-head; a linkage for translating movement of the print-head during an initial printing operation into movement of the stacking plate to position the record paper at a pick-up position of the feed roller. Preferably, the apparatus comprises means for preventing the operation of the linkage during normal reciprocation of the print-head. Preferably, the feed roller is adapted to rotate in reverse during the said initial printing operation and the means for preventing the operation of the linkage comprises means for moving the linkage into co-operation with the print-head when the feed roller is rotating in reverse. The means for preventing the operation of the linkage may comprise a clutch lever coupled to the feed roller and a tension spring coupled between the clutch lever and the linkage. Preferably, the linkage includes a first stage adapted to contact the print-head and to translate linear movement of the print-head into rotary movement and a second stage, positioned at least in part below the stacking plate and adapted to be rotated by rotary movement of the first stage and thus to contact and raise the stacking plate. The first stage may comprise a first gear shaft and a first bevel gear attached to it and the second stage may comprise a second gear shaft and a second bevel gear attached to it, the first and second bevel gears meshing together substantially at a right angle. Preferably, the second stage contacts the stacking plate via an intermediate plate against which it bears, a guide plate is provided to guide the leading edge of the intermediate plate and the trailing edge of the intermediate plate is pivoted on a hinge, so that upward movement of the second stage plate causes upward movement of only the leading edge of the intermediate plate. The intermediate plate may be divided into two halves adapted to contact respective sides of the stacking plate, one of the two halves being adapted to slide relative to the other to accommodate different sizes of record sheets stacked on the stacking plate. The apparatus may further comprise a plurality of auxiliary paper stacking plates adapted to be stacked upon each other, respectively having a width that decreases from rear to front and in which a lower plate is received in a bottom portion of an adjacent upper plate, and a discharged paper stacking plate on which a discharged paper is to be stacked. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described by way of example with reference to the accompanying drawings, in which: FIG. 1 is a perspective view of an ink jet printer according the present invention; FIG. 2 is a perspective view of the mechanism for moving the record paper stacking plate; FIG. 3 is further perspective view, in which the stacking plate is lifted; FIG. 4 is an exploded perspective view of a lifting lever; and FIG. 5 is a sectional view of the ink jet printer, showing a paper feed operation. BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGs. 1 and 2, the ink jet printer 100 according to the present invention includes a device 200 for feeding the record paper which has the record paper stacked upon it and is mounted at a front of the ink jet printer 100 for convenience. The device 200 has a stacking plate 221 for stacking the record paper and shifting plates 211 and 211' disposed below the stacking plate 221. The shifting plate 211 is separated from the shifting plate 211' and a space is present between the shifting plates 211 and 211'. The stacking plate 221 is disposed on mound 212 of the shifting plates 211 and 211' so that the record papers are stacked upon it. The ink jet printer 100 includes a pair of supporting frames 103 and 104 which respectively have a first projection 105 and a second projection 106 to combine an auxiliary feeding unit 250 with the ink jet printer 100 so that the auxiliary feeding unit 250 has some of the record papers stacked upon it. The auxiliary feeding unit 250 include an auxiliary stacking plate 253 used for stacking a record paper having a larger size, for example A3 sized paper, which has walls 251 and 252 respectively extending upwards from its edges. The walls 251 and 252 have a first engaging groove 251a and a second engaging groove 251b so that the auxiliary feeding unit 250 is combined with the main frame of the ink jet printer 100 in such a manner that the first and second engaging grooves 251a and 251b are engaged with the first and second projections 105 and 106 of the supporting frame 103 and 104. The auxiliary stacking plate 253 has a slidable stacking plates 254 and 255 disposed below its bottom surface. A grip 255a is formed to project upward from an edge of the slidable stacking plate 255. The auxiliary stacking plate 253 and the slidable stacking plate 254 respectively have grooves 253a and 253b on their edges to receive the grip 255a when the slidable stacking plates 254 and 255 are present in the auxiliary stacking plate 253. First and second record paper receiving plates 256 and 257 are assembled with the auxiliary stacking unit 253 in such a manner as to be connected through an engaging latch 258 with the walls 251 and 252. The second record paper receiving plate 257 is smaller in length that the first record paper receiving plate 256 and connected with the first record paper receiving plate 256 by a hinge. Further, the second record paper receiving plate 257 has first and second connecting slot 257a and 257b formed on its edge, to be assembled with the supporting frame 1034 and 104. A clutch 213b is mounted on a shaft for the feed roller 320, supported by the supporting frames 103 and 104. A tension spring 213a is connected between the clutch 213b and an operation lever 213. The clutch 213b pulls the operation lever 213 so that it approaches or contacts the guide shaft 102, so that the shifting plates 211 and 211' are moved upward as the carriage 410 is reciprocated along the guide shaft 102. When the record paper is fed to the print-head on the carriage 410, the feed roller 320 rotates reversely according to the electric signal of a ROM while the clutch 213b rotates in the same direction as the feed roller 320 and causes the operation lever 213, connected to the clutch by means of the tension spring 213a, to approach or contact the guide shaft 102. Then, the carriage 410 moving along the guide shaft 102 pushes the operation lever 213 outwards to a wall 101a so that the operation lever 213 reaches a hole 101b. Then, when the feed roller 320 rotates forward while feeding the record paper to the print-head, the operation lever 213 is moved away from the guide shaft 102 by means of the clutch 213b mounted on the shaft for the feed roller 320 and is contacts the main frame 101. Then, since the operation lever 213 is spaced from the guide shaft 102, the carriage 401 does not contact the operation lever 213 in spite of being reciprocated along the guide shaft 102. Thus, the operation lever 213 contacts the print-head, by use of the clutch 213b, only when the record paper is being fed to the print-head. A gear box 216 is assembled to the supporting frame 102 to receive first and second bevel gears 214 and 215 and the operation lever 213. Reference numeral 107 indicates a base plate on which the main frame 101, the supporting frames 103 and 104, the gear box 216, and the like are disposed. Reference numeral 108 indicates an encoder strip which detects a signal from a sensor mounted on the carriage 410 while the carriage 410 is reciprocally moved along the guide shaft 102. FIG. 2 is a view of the device 200 for feeding the record paper. In FIG. 2, the operation lever 213 is upright and the shifting plates 211 and 211' are present in a rest state and disposed on the supporting plates 204. The gear box 216 is separately positioned beside a first housing 201. The first and second bevel gears 214 and 215 are engaged with each other in a gear receiving chamber 216a defined by the gear box 216. The operation lever 213 is disposed in an operation lever receiving section 216b defined in the gear box 216, and is fitted to a first bevel gear shaft 214a at its lower end. The first bevel gear 214 is mounted on an end of the first bevel gear shaft 214a, which is engaged with the second bevel gear 215 mounted on a second bevel gear shaft 201 having a square section. The operation lever 213 is connected to the first bevel gear shaft 214a, which makes the first bevel gear shaft 214a rotate in the forward or reverse directions when the operation lever 213 is pushed by the carriage 410. On the other hand, the operation lever 214 is moved in the direction of the first bevel gear shaft 214a when being shifted by the clutch 213b. If the operation lever 213 is not moved, the shifting plates 211 and 211' are present in a horizontal state. The second bevel gear shaft 210 extends through a first housing 201, of which one end is supported by a second housing 202. The first and second housings 201 and 222 has a hinge axis at one end thereof is distal from the second bevel gear shaft 210. A guide place 218 is extended between the first and second housings 201 and 202. The guide plate 218 has an uneven upper surface 219, which is engaged with a locking element 217 disposed in the first housing 201 to restrain the first housing 201 as well as to change a position of the first housing 201. In that case, the locking element 217 is pushed and released from the uneven surface 219 of the guide plate 218 and then the position of the first housing 201 can be changed. Referring to FIG 3, the carriage 410 is moved along the shaft 102 to push the operation lever 213 which is positioned outside the printing region outward. The operation lever 213 is moved outward and the first bevel gear shift 214a is rotated clockwise. On the other hand, the second bevel gear 215 engaged with the first bevel gear 214 is rotated anticlockwise together with the second bevel gear shaft 210 as the first bevel gear 214 mounted on the first bevel gear shaft 214a is rotated clockwise. The shifting lever 207 is rotated by the second bevel gear shaft 210 to shift the shifting plate 211 upward, which in turn is pivoted on the hinge shaft 220 to an inclined position. At the same time, an operation member 208 is moved upward along guide channels formed in side walls 203 and 203' to incline paper guiding plates 206 as the shifting lever is rotated. Since the shifting plates 211 and 211' disposed on supporting plates 204 and the paper guiding plates 206 are inclined in the same direction, the record paper can be smoothly fed by the feed roller 320 as the stacking plate is disposed on the shifting plates 211 and 211'. When the printing is started and the feed roller 320 is rotated in the forward direction, the clutch 231b connected to a shaft of the feed roller in rotated clockwise to push the operation lever 213 from the guide shaft 102 to the main frame 101. Accordingly, the operation lever 213 is not operated even when the carriage 410 reciprocates along the guide shaft 102. Thus, even though the operation lever 213 is moved by the clutch 213b forward and backward, the first bevel gear shaft 214a is not rotated and the second bevel gear shaft 210 also is not rotated. FIG. 4 is an exploded perspective view of a shifting lever according to the present invention. The shifting lever 207 is assembled with a shifting lever support 207a and a spring 207b is disposed between the shifting lever 207 and the shifting lever support 207a. A through hole 207c is formed in the shifting lever support 207a, through which the second bevel gear shaft 210 is extended. Thus, the shifting lever support 207a is rotated together with the second bevel gear shaft 210. When the second bevel gear shaft 210 is rotated, the shifting lever 207 is shifted upward to push the operating member 208 so that the paper guiding plate 206 is inclined by means of the resilience of the spring 209. FIG. 5 is a sectional view of the ink jet printer according to the present invention, which shows a paper feed operation. When an initial printing is started or the carriage 410 is moved along the guide shaft 102 to push the operation lever 213 outward, to feed a new sheet of record paper, as described above, the second bevel gear shaft 210 is rotated to shift the shifting levers 207 disposed in the first and second housings upward. Thus, the shifting plates 211 and 211' are raised by the shifting levers 207. At the same time, the shifting lever 207 raises the operating member 208, which in turn moves the paper guiding plate 206 upward. Accordingly, the paper guiding plate 206 is inclined. Thus, the record paper stacked on the stacking plate 221 is picked-up by the feed roller 320 and moved to an upper portion of the base frame 530 during the rotation of the feed roller 320. At that time, the print-head on the carriage 410 starts to print the data on the record paper. As described above, the feed roller 320 picks up and moves the record paper stacked on the stacking plate 221 of the device for feeding the record paper in the ink jet printer. At the end, the record paper is discharged from the printer by means of a star-shaped wheel 531 and a discharging roller 532 to be stacked on a first record paper receiving plate 256 and a second record paper receiving plate 257. Reference numeral 105 indicates the first projection and 106 indicates the second projection. Reference numeral 251 indicates a side wall and 258 indicates the connecting latch used for combining the first and second record paper receiving plates 256 and 257 with the side wall 251. As described above, the record paper is picked up by rotation of the feed roller and moved to a base frame. As a result, it is possible to save the time taken to feed the record paper and printing data on the record paper. Further, there is an advantage in that the time for picking up the record paper can be reduced by using a CR (carriage return) motor having a large torque.

Claims: An image-forming apparatus comprising: a reciprocating print-head (411); a stacking plate (221) for supporting a stack of record sheets; a feed roller (320) for feeding a record sheet stacked on the plate (221) to a printing region of the print-head (411); characterised by a linkage (213, 214, 215, 210, 207) for translating movement of the print-head (411) during an initial printing operation into movement of the stacking plate (221) to position the record paper at a pick-up position of the feed roller (320). Apparatus according to claim 1 comprising means for preventing the operation of the linkage during normal reciprocation of the print-head. Apparatus according to claim 2 in which the feed roller is adapted to rotate in reverse during the said initial printing operation and the means for preventing the operation of the linkage comprises means for moving the linkage into co-operation with the print-head when the feed roller is rotating in reverse. Apparatus according to claim 3 in which the means for preventing the operation of the linkage comprises a clutch lever coupled to the feed roller and a tension spring coupled between the clutch lever and the linkage. Apparatus according to any preceding claim in which the linkage includes: a first stage adapted to contact the print-head and to translate linear movement of the print-head into rotary movement; a second stage, positioned at least in part below the stacking plate and adapted to be rotated by rotary movement of the first stage and thus to contact and raise the stacking plate. Apparatus according to claim 5 in which: the first stage comprises a first gear shaft and a first bevel gear attached to it; the second stage comprises a second gear shaft and a second bevel gear attached to it, the first and second bevel gears meshing together substantially at a right angle. Apparatus according to claim 5 or claim 6 in which second stage contacts the stacking plate via an intermediate plate against which it bears, a guide plate is provided to guide the leading edge of the intermediate plate and the trailing edge of the intermediate plate is pivoted on a hinge, so that upward movement of the second stage plate causes upward movement of only the leading edge of the intermediate plate. Apparatus according to claim 7 in which the intermediate plate is divided into two halves adapted to contact respective sides of the stacking plate, one of the two halves being adapted to slide relative to the other to accommodate different sizes of record sheets stacked on the stacking plate. Apparatus according to any preceding claim further comprising a plurality of auxiliary paper stacking plates adapted to be stacked upon each other, respectively having a width that decreases from rear to front and in which a lower plate is received in a bottom portion of an adjacent upper plate, and a discharged paper stacking plate on which a discharged paper is to be stacked. Apparatus according to any preceding claim which is an ink jet printer.

Inventors: YUN SUK-JIN, YUN, SUK-JIN
Applicants: SAMSUNG ELECTRONICS CO LTD, SAMSUNG ELECTRONICS CO., LTD.
Application year: 1998
Main classification: B41J13
IPC codes: B41J13, B65H1