Patent Publication Number: US-6659444-B2

Title: Sheet feed apparatus, and recording apparatus having sheet feed apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sheet feed apparatus and a recording apparatus having the sheet feed apparatus, and more particularly, to a sheet feed apparatus capable of performing manual sheet feeding and a recording apparatus having this sheet feed apparatus. 
     2. Related Background Art 
     Conventionally, a recording apparatus such as a printer, a copying machine, a facsimile apparatus or the like ordinarily has a sheet feed apparatus for feeding sheets stored in a sheet storing means by using a sheet feed means. The sheets fed by the sheet feed apparatus are transported to an image recording unit by a sheet transportation means, and images are to be recorded on the sheets in the image recording unit. 
     As such the sheet feed apparatus, there is provided a sheet feed apparatus capable of performing manual sheet feeding so as to record images not only on standard sheets stored in the sheet storing means but also on nonstandard sheets designated by a user. 
     However, in this conventional sheet feed apparatus capable of performing the manual sheet feeding and the recording apparatus having this sheet feed apparatus, a dedicated sheet feed roller for the manual sheet feeding has to be added, and a space for the manual sheet feeding has to be separately secured. 
     Thus, if the dedicated sheet feed roller is added and the space for the manual sheet feeding is secured, the structure becomes complex and the size of the apparatus becomes large as a whole, and costs increase because the number of parts increases. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a sheet feed apparatus capable of performing manual sheet feeding with simple structure at low costs, and a recording apparatus having such the sheet feed apparatus. 
     Another object of the present invention is to provide a sheet feed apparatus which comprises a sheet storing means for storing sheets; a sheet feed means, disposed in a state capable of closing to and leaving from the sheets stored in the sheet storing means, for feeding the sheets; a manual sheet feed unit disposed above the sheet storing means; and a guide member, disposed in the manual sheet feed unit, for guiding the manually fed sheets to the sheet feed means while underpropping those sheets, wherein the guide member is formed by a flexible member. 
     Still another object of the present invention is to provide a recording apparatus which comprises a head mounting unit for mounting a recording head; a sheet storing means for storing sheets; a sheet feed means, disposed in a state capable of closing to and leaving from the sheets stored in the sheet storing means, for feeding the sheets; and a guide member, disposed above the sheet storing means, for guiding the manually fed sheets to the sheet feed means while underpropping those sheets, wherein the guide member is formed by a flexible member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing an ink-jet printer being an example of a recording apparatus equipped with a sheet feed apparatus according to an embodiment of the present invention; 
     FIG. 2 is a sectional view showing the schematic structure of the ink-jet printer; 
     FIG. 3 is a sectional view showing the structure of the sheet feed apparatus; 
     FIG. 4 is a side-view showing the locking state of the sheet feed apparatus; 
     FIG. 5 is a perspective view showing the structure of a sheet feed cassette of the sheet feed apparatus; 
     FIG. 6 is a side-view showing a state in case of manual sheet feeding in the sheet feed apparatus; and 
     FIG. 7 is a view for explaining the structure of a manual guide unit provided in the sheet feed apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, the embodiments of the present invention will be explained in detail with reference to the attached drawings. 
     FIG. 1 is a perspective view showing an ink-jet printer being an example of a recording apparatus equipped with a sheet feed apparatus according to the embodiment of the present invention. 
     In FIG. 1, numeral  1  denotes the ink-jet printer, numeral  1 A denotes a printer main body (hereinafter called a main body), and numeral  3 A denotes an image recording unit. The image recording unit  3 A has a recording head  3  and a carrier  2  used to mount the recording head  3 . 
     The recording head  3  is structured to have plural nozzle arrays (not shown) in the sub scanning direction on the surface opposite to sheets P to discharge different color inks for each nozzle array. The ink is supplied to each color nozzle array in the recording head  3  from an ink tank  4  through a supply tube  5 . The carrier  2  is slidably supported along a guide shaft  7  and a guide rail  8 , of which the both ends are fixed to a frame  6  of the main body  1 A, mutually disposed in parallel. 
     Images are recorded on the sheet by discharging the ink toward the sheet P from the recording head  3  while reciprocating the carrier  2 . It should be noted that the carrier  2  is reciprocated by a belt driving apparatus and a motor (both not shown). 
     FIG. 2 is a sectional view showing the schematic structure of the ink-jet printer  1 . In FIG. 2, numeral  1 B denotes a sheet feed apparatus. The sheet feed apparatus  1 B has a sheet feed cassette  10  being a sheet storing means detachably installed in the main body  1 A, and a sheet feed roller  15  being a sheet feed means to feed the sheets P stored in the sheet feed cassette  10 . 
     The sheet feed cassette  10  has a separation board  19  being an inclined plane member which is in contact with the sheets P fed by the rotation of the sheet feed roller  15  at the end of the downstream side of the sheet feed direction, so as to separate the sheet P. 
     The sheet feed roller  15  is provided above the sheet feed cassette  10 . The roller  15  is stored rotatively by an arm  14 , being a supporting member, also rotatively supported by a fulcrum  14   a  on the upstream side of the sheet feed roller  15 , and in a state capable of closing to and leaving from the sheets P stored on the sheet feed cassette  10 . 
     When the images are recorded, the sheet feed roller  15  comes into contact with an uppermost sheet P 1  of the sheets P stored on the sheet feed cassette  10  owing to the weight of the roller  15  itself and the downward rotative motion of the arm  14 . Then, the sheet feed roller  15  is rotated by the driving force from a not-shown driving source transmitted through a pulley  16 , a belt  17  and a gear  18  shown in FIG.  3 . 
     In FIG. 2, numeral  9  denotes a transportation roller, numeral  24  denotes a U-turn roller, and numeral  23  denotes a roller guide provided at the position opposite to the U-turn roller  24 . The sheet P 1  fed by the rotation of the sheet feed roller  15  is transported to the transportation roller  9  through a sheet transportation path R formed between the U-turn roller  24  and the roller guide  23 . 
     Next, an image recording operation of the ink-jet printer  1  structured as above will be explained. 
     At first, the sheet feed roller  15  comes into contact with the uppermost sheet P 1  of the sheets P stored on the sheet feed cassette  10  owing to the weight of the roller  15  itself and the downward rotative motion of the arm  14 . In this state, the sheets P are fed if the sheet feed roller  15  rotates. Then, only the uppermost sheet P 1  is separated by the separation board  19  (due to inclined plane separation), and the separated sheet P 1  is then transported to the roller guide  23  while being in contact with the separation board  19 . 
     The uppermost sheet P 1  enters the sheet transportation path R and is then guided to a nipped portion between the transportation roller  9  and a pinch roller  12  by the rotation of the U-turn roller  24 . The sheet P 1  is further transported to a platen  25  provided on the recording position opposite to the recording head  3  in a state that the sheet P 1  is being nipped between the transportation roller  9  and the pinch roller  12 . 
     Next, for the sheet P 1  transported to the platen  25  as above, the recording operation by the recording head  3  mounted on the carrier  2  is started. If the recording operation for one scan by the recording head  3  ends, the recording operation is once interrupted, and the sheet P 1  on the platen  25  is transported for a predetermined amount by the transportation roller  9 . Then, a recording operation for next one scan is performed while moving again the carrier  2  along the guide shaft  7 . After sequentially performing the recording operations by the recording head  3  on the platen  25  as above, the sheet is discharged on a cassette cover  13  by a sheet discharge roller  11   a  and a sheet discharge spur  11   b.    
     In FIG. 1, numeral  11  denotes a head recovery means. The head recovery means  11  is provided at the position which becomes opposite to the recording head  3  when the carrier  2  moves to a home position provided in the vicinity of one end of the moving range of the carrier  2 . The head recovery means  11  is operated in a recording standby state, before/after the recording operation, or in an interval between successive one-line recording operations, so as to perform various operations such as capping, absorption, wiping and the like to the recording head  3 , whereby clogginess or the like of the recording head  3  is prevented, and thus the performance of the recording head  3  is maintained. 
     Incidentally, in the present embodiment, a manual lever  20  being a lever member is provided as shown in FIG. 3 so that manual sheet feeding can be performed. In case of performing the manual sheet feeding, the manual lever  20  has to be pulled toward the direction indicated by an arrow A. When the manual lever  20  is pulled, the manual lever  20  rotatively moves clockwise around a manual lever shaft  20   a  treated as a fulcrum. When the manual lever  20  rotatively moves, an action part  20   b  provided at the inner end of the manual lever  20  rotatively moves downward to depress a release boss  14   b  being an engagement part of the arm  14 . 
     The release boss  14   b  is provided at the manual lever side (upstream side of the sheet feed direction) across the arm shaft  14   a.  Consequently, as shown in FIG. 4, the sheet feed arm  14  rotatively moves counterclockwise around the arm shaft  14   a  as indicated by an arrow B, whereby the sheet feed roller  15  comes to a state of leaving from the sheets P set in the cassette  10 . 
     On the other hand, as shown in FIG. 4, the cassette cover  13  being a cover member disposed on an upper surface of the sheet feed cassette  10  covers a part of the upstream side of the sheet feed direction of the sheet feed cassette  10 . An aperture  10 A for the manual sheet feeding is disposed at the downstream side of the sheet feed direction of the sheet feed cassette  10  not covered by the cassette cover  13 . 
     Next, a manual sheet feeding operation of the ink-jet printer  1  as structured above will be explained. 
     In case of performing the manual sheet feeding operation, at first, the sheet feed roller  15  has to be in a state of leaving from the sheets by using the manual lever  20  as shown in FIG.  4 . Next, as shown in FIG. 5, a manual feed sheet PA is fed from the aperture  10 A for the manual sheet feeding along a sheet base rib  13   a  provided in the cassette cover  13  with a state that the sheet PA reaches the separation board  19  of the sheet feed cassette  10 . 
     Subsequently, in this state, the manual lever  20  is rotatively moved backward against the direction indicated by the arrow A to release the locking state of the arm  14 , whereby, as shown in FIG. 6, the sheet feed roller  15  comes into contact with the uppermost sheet PA 1  of the manually fed sheets PA. Thereafter, the sheet PA 1  is transported to the image recording unit  3 A by the rotation of the sheet feed roller  15  which is in a state of being in contact with the sheet PA 1 . 
     Incidentally, in FIGS. 5 and 6, numeral  21  denotes a manual guide unit being a guide member which is provided at the downstream side of the sheet feed direction of the cassette cover  13  and used to guide the sheets PA to be manually fed to the position below the sheet feed rollers  15  while underpropping the sheets PA. This manual guide unit  21  is disposed at a position opposite to the sheet feed rollers  15  when the sheet feed cassette  10  is installed in the main body  1 A. It should be noted that this manual guide unit  21  has flexibility so that the manual feed sheets PA can be surely guided to the position below the sheet feed rollers  15 . 
     In this manner, the manual guide unit  21  having the flexibility is disposed at the aperture  10 A for the manual sheet feeding provided on the upper surface of the sheet feed cassette  10 , and the manual feed sheets PA are guided to the position below the sheet feed rollers  15  by the manual guide unit  21 , whereby the manual sheet feeding can be performed with the simple structure at low costs. Further, a space for the manual sheet feeding and the number of parts can be minimized. 
     On the other hand, as shown in FIG. 5, apertures  21 A for the contact of the manual guide unit  21  are provided at the positions opposite to the sheet feed rollers  15 . By providing the apertures  21 A for the contact, even when the manual sheet feeding is not performed, the sheet feed rollers  15  can come into contact with the uppermost sheet P 1  stored on the sheet feed cassette  10 , and the sheets stored in the sheet feed cassette  10  can be sent out. 
     Incidentally, the manual guide unit  21  sometimes does not bend downward due to its rigidity (toughness), or if the manual guide unit  21  bends, the bent magnitude is sometimes resulted in insufficient. In this case, if the sheet feed rollers  15  rotatively move downward upon decreasing the sheets stored in the sheet feed cassette  10 , a shaft  15   a  of the sheet feed rollers  15  comes into contact with a part between the apertures of the manual guide unit  21 . When the shaft  15   a  of the sheet feed rollers  15  comes into contact with the manual guide unit  21 , the sheet feed rollers  15  are not completely fallen due to the rigidity (toughness) of the manual guide unit  21 , and the sheet feed rollers  15  sometimes can not come into contact with the sheets P stored on the sheet feed cassette  10 . 
     Therefore, in the present embodiment, the manual guide unit  21  is structured by the member having the flexibility so that the manual guide unit  21  can bend downward when the shaft  15   a  of the sheet feed rollers  15  comes into contact with the manual guide unit  21 . That is, the manual guide unit  21  is structured by the member having such the rigidity capable of being bent together with the sheet feed rollers  15  when the manual guide unit  21  is in contact with the shaft  15   a  of the sheet feed rollers  15 . According to this structure, even if the number of the sheets stored in the sheet feed cassette  10  decreases, the sheet feed rollers  15  can rotatively move downward, and the sheets P are surely sent out. 
     On the other hand, in case of sending out the sheets PA manually fed by the sheet feed rollers  15 , the sheets P stored on the sheet feed cassette  10  have not to be transported together with the sheets PA. Accordingly, it is required to structure that the sheets PA do not come into contact with the sheets P stored on the sheet feed cassette  10  even if the sheet feed rollers  15  dig into the sheets PA manually fed when the sheets are fed. 
     Therefore, in the present embodiment, thickness (height size) around the apertures of the manual guide unit  21  is structured thicker than that of the manual feed sheets PA as shown in FIG.  7 . For example, if the thickness of the manual feed sheets PA is about 0.2 mm, the thickness around the apertures may be set to 0.8 mm to 1.0 mm. According to this structure, the manual feed sheets PA and the sheets P stored on the sheet feed cassette  10  are not transported in a state of overlapping each other. 
     Furthermore, when the few manual feed sheets PA are remained, for example, the last two sheets are remained, in order to surely separate the second to the last sheet from the last sheet, a separation sheet  22  being a friction member consisted of the material having a large friction coefficient such as the leather article or the like is pasted around the aperture. As a result, it is structured that the thickness around the aperture when the separation sheet  22  is pasted becomes such the thickness of 0.8 mm to 1.0 mm. According to this structure, even if plural sheets are manually fed, the sheet transportation can be surely performed until the last manual feed sheet without occurring the sheet overlapped transportation. 
     The above embodiment is structured in that the present invention is applied to a serial type recording apparatus of moving the recording head in the main scanning direction. However, the present invention is also applicable to a full-line type recording apparatus which records images by a recording head while sequentially transporting recording sheets using the recording head extensively exists for the whole area of the recording sheet width direction. 
     Further, in the above embodiment, an example of using a recording head of the so-called BJ (bubble-jet) system in the ink-jet system was explained. However, the present invention is not limited to the recording system of this kind of the recording head, but may be applied to various recording systems. The recording system of the recording head can be, for example, a piezoelectric system other than the BJ system, and a recording head based on a system having various recording elements such as a thermal transfer system or the like can be used besides the ink-jet system. 
     As explained above, according to the present invention, the guide member formed by the flexible member is disposed at the aperture for the manual sheet feeding provided on the upper surface of a sheet storing means, and the sheets are to be guided to the position below a sheet feed means by the guide member, while underpropping the sheets, whereby the manual sheet feeding can be performed with the simple structure at low costs.