The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
A feed device according to an embodiment of the invention and a recording apparatus being one example of a liquid ejecting apparatus that uses the feed device are described below. Firstly, a general structure of an ink jet printer as the best mode for carrying out a liquid ejecting apparatus according to an embodiment of the invention and a recording apparatus being one example thereof is schematically described below with reference to the drawings.
As illustrated in
The hopper 220 can swing on an upper back portion of the ink jet printer 100 such that a lower portion of the hopper 220 can come into contact with and be separated from the feed roller 231. Specifically, the lower portion of the hopper 220 is normally biased against the feed roller 231 by biasing force (not shown). A shaft 133 on which the feed roller 231 is disposed can be rotated by a power device (not shown). A second cam 132 on the shaft 133 is rotated with rotation of the shaft 133, comes into contact with the lower portion of the hopper 220, and thus causes the hopper 220 to swing.
The sheets P are restricted in a main scanning direction X by a pair of side-end restricting units 221 disposed on the hopper 220 in the main scanning direction X. A sub-scanning direction Y is the direction of transport of the sheets P. The sheets P stacked on the hopper 220 are supported from below by the bank portion 211 as an end support portion disposed on a feed base portion 260 being a base of the feed unit 110. It is, of course, to be understood that the feed base portion 260 may be integral with a base unit 210 of the ink jet printer 100.
The timing of swinging of the hopper 220 is described below. While the feed roller 231, which has a shape of “D” in side view, is rotated one rotation counterclockwise in
A retard roller 233 being one example of a separation unit 232 is disposed on the base unit 210 so as to face the feed roller 231. The rotation of the retard roller 233 needs a certain load. These components are disposed so as to satisfy the following relationship:
μ1>μ3
μ2>μ3
where μ1 is the coefficient of friction between the feed roller 231 and the sheet P, μ2 is the coefficient of friction between the retard roller 233 and the sheet P, and μ3 is the coefficient of friction between the sheets P. Therefore, even if a plurality of sheets invade a front opening 245 (see
Subsequently, when the hopper 220 returns to the original place distant from the feed roller 231, a first cam 131 disposed on the shaft 133 comes into contact with a cam follower 134. The cam follower 134 is provided with a return lever member 250 which pushes a sheet back to the bank portion 211 upstream. As will be described below, the return lever member 250 includes a plurality of lever units 251, a lever base 256 being its base, and the cam follower 134. The lever units 251 and the cam follower 134 are integral with each other via the lever base 256.
The return lever member 250 can pivot together with the rotation of the cam follower 134. The return lever member 250 can be protruded into and retracted from a feed path 109 from and to below first guide 112 through lever insertion openings 114 of the feed base portion 260. The lever units 251 can push back to the hopper 220 another sheet almost unnecessarily being fed when a sheet P is being fed by the feed roller 231. Therefore, the sheet restricted by the retard roller 233 is returned to the hopper 220 by the lever units 251 of the return lever member 250.
The sheet P fed to the pair of transport rollers 240 is subjected to a so-called skew removal.
The “skew removal” can use a so-called “nip and release method”, in which a leading end of the sheet P is nipped between the pair of transport rollers 240 and then the end is released by reversed rotation of the pair of transport rollers 240 to bend the sheet P, or a so-called “abutment method”, in which a leading end of the sheet P abuts against the pair of transport rollers 240 to bend the sheet P.
The pair of transport rollers 240 includes a transport driving roller 241 driven by a power from a power device and a transport driven roller 242 rotated by the transport driving roller 241. The transport driven roller 242 is rotatably hold by a holder 244 and is biased against the transport driving roller 241.
The sheet P is transported to the recording unit 120 by the rotation of the transport driving roller 241. The recording unit 120 records information on the sheet P.
The recording unit 120 includes a recording head 123 which ejects ink onto the sheet P, a platen 124 which supports the sheet P from below and guides the sheet P to a place that faces the recording head 123, a carriage 121 which moves the recording head 123 thereon in the main scanning direction X, and a carriage guide 122 which is attached to the base unit 210 and guides the carriage 121 in the main scanning direction X.
While the sheet P is transported by the rotation of the transport driving roller 241, the carriage 121 scans in the main scanning direction X and the recording head 123 ejects ink, thereby recording information.
In the feed path 109 for the sheet P in the feed device 200, at a side where the sheet P is supported from below in a vertical direction and is guided to the pair of transport rollers 240, the first guide 112 is disposed at the LSD side, which is adjacent to the feed roller 231, and a retraction guide 111 retracted below with respect to the first guide 112 is disposed at the MSD side in the main scanning direction X. The place of the feed roller 231 is biased toward the LSD side with respect to the center of the entire width of the feed path 109. As a result, if the MSD-side portion of the sheet P floats because the pressing force of the feed roller 231 is not substantially applied to the MSD-side of the sheet P, the feed path 109 at the MSD side may be shorter than that at the LSD side. To address this problem, the retraction guide 111 is retracted with respect to the first guide 112 by an amount of shortness so that the feed path 109 at the MSD side is increased. Therefore, the difference between the feed path 109 at the MSD side and that at the LSD side can be reduced, and the possibility of the occurrence of a skew caused by this difference can be suppressed.
The MSD-side portion of the shaft 133 for the feed roller 231 is supported by a bearing (not shown) disposed on the back of the carriage guide 122.
In the specification, a “first position” of the lever units 251 of the return lever member 250 refers to a position at which the lever units 251 are retracted from the feed path 109. The “second position” refers to the most upstream end in a stroke of each of the lever units 251, and at this position, the lever units 251 protrude above the bank portion 211. The “third position” refers to a position between the first and second positions, and at this position, a return operative portion 252 of each of the lever units 251 blocks the feed path 109.
The sheets P refer to general sheets of paper, a sheet P1 is a sheet of paper to be fed, a sheet P2 refers to a sheet of paper that has unnecessarily entered the feed path, and sheets P3 refers to sheets of paper stacked on a hopper.
As illustrated in
Although operations will be described below, each of the lever units 251 functions to return the sheet P2 (see
The front opening 245 is defined by the first guide 112 below the feed path 109 and the feed roller 231 above the feed path 109. The feed path 109 between the feed roller 231 and the pair of transport rollers 240 is defined by the first guide 112 disposed therebelow and a second guide (not shown) provided on the lower portion of the holder 244 disposed thereabove.
Each of the lever units 251 includes the return operative portion 252 which pushes back upstream the sheet P2 and a raising portion 253 nearer the pivot than the return operative portion 252. The raising portion 253 includes an slant section 255 gradually rising with respect to the return operative portion 252.
Alternatively, the raising portion 253 may include a stepped section 254 being a step disposed on the return operative portion 252. The raising portion 253 may have any shape as long as it can raise the leading end of the sheet P2 above the bank portion 211. Therefore, the shape of the raising portion 253 is not limited to the disclosed embodiments.
As illustrated in
The degree of descent of a leading end of the sheet P2 that is not directly raised by the lever unit 251 (e.g., the MSD side) by its own weight below a leading end of the sheet P2 that is directly raised by the lever unit 251 (e.g., the LSD side) differs depending on the size and type of the sheet P and the location and size of the lever unit 251. Therefore, the degree of protrusion of the slant section 255 above the bank portion 211 is determined in consideration of these factors.
The expression “the slant section 255 is substantially parallel to the bank portion 211” used herein is such that the slant section 255 is substantially parallel to the bank portion 211 while the slant section 255 protrudes above the bank portion 211 during the pivoting of the slant section 255 together with the pivoting of the lever unit 251.
As illustrated in
As illustrated in
The hopper 220 is biased by a coil spring (not shown) in a direction at which the hopper 220 pivots clockwise about a hopper pivot 220b at the upper portion of the hopper 220. The biasing force brings about the engagement between a projection 220a at the lower portion of the hopper 220 and a depression 132a of the second cam 132.
The feed base portion 260 is also provided with a cam-follower insertion opening (not shown) for allowing the cam follower 134 to pass therethrough. The both sides of the cam-follower insertion opening in the main scanning direction X are provided with a pair of follower guides 270 which regulates the position and attitude (inclination) of the cam follower 134 in the main scanning direction X throughout a range of rotation of the cam follower 134.
As previously described, in the “third position” of the lever unit 251, the return operative portion 252 of the lever unit 251 blocks the feed path 109. This can prevent the sheets P stacked on the hopper 220 from entering the front opening 245.
As illustrated in
The lever units 251 and the cam follower 134 are formed integrally with each other via the lever base 256. The lever base 256 extends along the main scanning direction X, is formed on the both ends in the main scanning direction X, and can pivot about the lever fulcrums 257 supported by the feed base portion 260.
Therefore, together with counterclockwise rotation of the cam follower 134, the lever units 251 pivot counterclockwise.
The lever fulcrums 257 at the both ends of the lever base 256 are rotatably supported by the feed base portion 260.
As illustrated in
Together with the rotation of the shaft 133, the lever units 251 pivot further counterclockwise and are retracted with respect to the first guide 112 in the feed path 109. This retracted position is the “first position” of the lever units 251.
As illustrated in
As illustrated in
The second cam 132 moves the projection 220a disposed at the lower portion of the hopper 220 against the above-described biasing force. Therefore, the hopper 220 pivots counterclockwise about the hopper pivot 220b such that the lower portion of the hopper 220 becomes separated from the feed roller 231.
As illustrated in
As illustrated in
During the states illustrated in
As illustrated in
The time at which the return operative portion 252 is protruded from the first guide 112 is a time immediately before the chord of the feed roller 231, which has a shape of “D” in side view, becomes separated from the retard roller 233 and, that is, a time immediately before the sheet P2 stopping at the retard roller 233 becomes released. As a result, there is no possibility of moving the sheet P2 stopping at the retard roller 233 downstream. In addition, the sheet P2 stopping at the retard roller 233 can be pushed back upstream by a reduced force.
As illustrated in
The operation itself of feeding the single sheet P1 to the pair of transport rollers 240 by the feed roller 231 is completed in
As illustrated in
As illustrated in
For example, this is highly effective for when the number of the lever units 251 is small relative to the length of the feed path 109 in the main scanning direction X or when the number of the lever units 251 is small and the places of the lever units 251 are biased with respect to the center of the feed path 109 in the main scanning direction X. In other words, in the feed device according to the embodiment of the invention, the number of lever units 251 and the length of the return lever member 250 in the main scanning direction X can be reduced. As a result, compared with known arts, dimensional control in manufacture of the return lever member can be facilitated. Since the length of the return lever member in the main scanning direction X is short, costs can also be reduced. In addition, distortion caused by twisting can be reduced.
As illustrated in
When the shaft 133 is further rotated clockwise, the state shifts to the stand-by state illustrated in
The stroke of the lever unit 251 according to the embodiment of the invention is longer by an amount corresponding to the stroke from the “second position” to the “third position” than that according to the known feed device. The number of positions that the lever unit 251 can take according to the embodiment of the invention is three, whereas the number of positions of the lever unit according to the known feed device is two.
The feed device 200 according to the present embodiment includes the feed roller 231 which picks up the sheet P1 as a recording medium from sheets stacked on the hopper 220 as a stacking unit and the bank portion 211 and which feeds the sheet P1 downstream via the feed path 109 and the return lever member 250 which pushes back upstream the sheet P2, which has unnecessarily entered the feed path 109 in feeding the sheet P1 downstream. The stacking unit includes the bank portion 211 as an end support portion that supports the leading end of the sheets P1 to P3 from below. The return lever member 250 includes the lever base 256 and the lever units 251. The lever base 256 and the lever units 251 are formed integrally with each other. The lever base 256 is a shaft extending in the main scanning direction X, which is the direction of width of the sheet P. The lever units 251 radially extend from the lever base 256 and can be protruded into and retracted from the feed path 109 by pivoting of the lever base 256. When protruding into the feed path 109, the lever unit 251 pushes back the sheet P2 upstream. Each of the lever units 251 includes the return operative portion 252 which pushes back upstream the sheet P2 and the raising portion 253 which raises the sheet P2 above the bank portion 211.
The lever units 251 may be moved to the first position, at which the lever units 251 are retracted from the feed path for the sheet P, the second position, at which the raising portion 253 protrudes above the bank portion 211 and raises the leading end of the sheet P2 upward, and the third position, at which the raising portion 253 does not protrude above the bank portion 211 and the return operative portion 252 blocks the feed path 109. The lever units 251 may pivot from the first position to the second position such that the return operative portion 252 is moved upstream in the feed path 109, pivot from the second position to the third position such that the return operative portion 252 is moved downstream in the feed path 109, and pivot from the third position to the first position such that the return operative portion 252 is moved downstream.
The raising portion 253 according to the present embodiment may include the stepped section 254 protruding with respect to the return operative portion 252.
Alternatively, the raising portion 253 according to the present embodiment may include the slant section 255 rising with respect to the return operative portion 252. The slant section 255 may be substantially parallel to the bank portion 211 while the slant section 255 protrudes above the bank portion 211.
According to the present embodiment, the place of the feed roller 231 is biased with respect to the center of the feed path 109 in the main scanning direction X. The return lever member 250 includes at least two lever units 251 in the main scanning direction X. The at least two lever units 251 are adjacent to opposite sides of the feed roller 231.
The ink jet printer 100 according to the present embodiment includes the feed unit 100 which picks up the sheet P from the stacked sheets and which feeds the sheet P to the recording unit and the recording unit 120 which records information by ejecting ink to the sheet P. The feed unit 100 includes the feed device 200 described above.
Two lever units described in the embodiment may be replaced with one lever unit or three or more lever units. In the case of one lever unit, it is preferable that the return operative portion and the raising portion be wide in the main scanning direction.
The invention is not limited to the above-described embodiment. It is, of course, to be understood that that various modifications may be made within the scope of the following claims, and the invention encompasses the modifications.
Number | Date | Country | Kind |
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2006-171988 | Jun 2006 | JP | national |