1. Field of the Invention
The present invention relates to a recording medium cutting apparatus that cuts off unwanted portions of a recording medium, to obtain single-leaf products of a target size from the recording medium.
2. Description of the Related Art
Conventionally, in image forming apparatus that can obtain single-leaf sheet-like image product, the apparatus can be broadly divided into one that forms an image on a medium of a target size of the product, and one that forms an image on a medium larger than the target size, and subsequently cut unwanted portion to attain the target size.
The apparatus that performs cutting after image formation like the latter includes a large scale apparatus that can obtain a single-leaf product from a roll-like continuous sheet. Such an apparatus has therein a conveyance unit and a cutting unit of a sheet, and separates unwanted portions from the products inside the apparatus.
Separation of the unwanted portions from the products including the cutting unit is generally demanded to respond to various sizes by the identical apparatus.
Japanese Patent Application Laid-Open No. 2007-22070 discusses a cutting unit for cutting trailing edge of a sheet on which an image has been recorded and an unwanted portion separation unit. Japanese Patent Application Laid-Open No. 2007-22070 discusses a method for responding to various purposes such as guiding of a sheet to a cutting and conveyance unit, sandwiching, separation from the conveyance path, by employing a movable type of a paper guide on the upstream downside of a cutter serving as the cutting unit provided in the conveyance path, and by changing a position of the movable paper guide.
With respect to this type of image forming apparatus, as well as mixing of different products with various cutting lengths, performing control for cutting and separation in response to media with various thicknesses or different rigidities also exist as demand issues. Further, even in relation to a layout inside the apparatus, demands for arranging the cutting unit by making the conveyance path other than horizontal or enhancement of processing speeds also have arisen.
In a unit discussed in Japanese Patent Application Laid-Open No. 2007-22070, separation of the unwanted portions after cutting always involves an operation of the paper guide, and since the separation mainly utilizes gravity, an operation time per one cycle which surely enables the separation is liable to become longer.
One aspect of the present invention is directed to discarding portions cut off from a recording medium from the conveyance path in a reliable manner and at a high speed.
According to an aspect of the present invention, a recording medium cutting apparatus includes a conveyance unit configured to convey a recording medium, a conveyance path on which the recording medium to be conveyed by the conveyance unit passes, a cutting unit configured to cut the recording medium, a discharge port provided on the midway of the conveyance path, for discharging from the conveyance path a portion cut off from the recording medium by the cutting unit, and a discharge unit configured, when the recording medium is cut, to come into contact with the recording medium from an opposite side to the discharge port, to cause a portion to be cut off from the recording medium to be positioned toward an outside of a conveyance path from the discharge port.
Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings.
Hereinbelow, exemplary embodiments in a printer using an inkjet method will be described. The printer of the example is a high-speed line printer using a continuous sheet wound into a roll shape and is suitable for printing of a huge amount of sheets in, for example, a print labo.
Inside the printer, there are mainly provided respective units of a sheet supplying unit 1, a decurling unit 2, a skew correction unit 3, a print unit 4, an inspection unit 5, a sheet cutting and conveying unit 6, an information recording unit 7, a drying unit 8, a discharging and conveying unit 10, a sorter unit 11, a discharge tray 12, and a control unit 13. The sheet is conveyed by the conveying mechanism including roller pairs and belts along the sheet conveyance path represented with solid lines in
The sheet supplying unit 1 accommodates and supplies the continuous sheet wound in a roll shape. The sheet supplying unit 1 is configured to accommodate two rolls P1 and P2, and to alternatively pull out and supply the sheet from either roll. The number of accommodatable rolls is not limited to two, and the sheet supplying unit that accommodates one or three or more rolls may be used.
The decurling unit 2 is a unit that eliminates curl (warpage) of the sheet supplied from the sheet supplying unit 1. In the decurling unit 2, the curl is eliminated by pressing the continuous sheet against circumferential surface of one drive roller using two pinch rollers, and by conveying the sheet while making the sheet to be curved so as to cause the warpage reversely to the curl.
The skew correction unit 3 is a unit that corrects a skew (inclination relative to an original traveling direction) of the sheet which has passed through the decurling unit 2. The skew of the sheet is corrected by pressing a sheet side edge on a reference side against the guide member.
A print unit 4 is a unit that forms an image on the sheet by the print head 14 with respect to the conveyed sheet. The print unit 4 is provided with a plurality of conveyance rollers which conveys the sheet. The print head 14 has a line type print head in which nozzle arrays of the inkjet method are formed within a range that covers a maximum width of the sheets which are assumed to be used.
The print head 14 is configured such that a plurality of print heads is aligned along the conveying direction. Each print head 14 is disposed parallel to one another. The inkjet method can employ a method using heating elements, a method using piezoelectric elements, a method using electrostatic elements, a method using micro-electro-mechanical systems (MEMS) elements or the like. Inks for respective colors each are supplied to the print head 14 via ink tubes from ink tanks.
The inspection unit 5 optically reads out inspection pattern or an image printed on the sheet by the print unit 4, and inspects a state of nozzles of the print heads, a sheet conveyance state, an image position and so forth.
The sheet cutting and conveying unit 6 is equipped with a mechanical cutter that cuts to a predetermined length the sheet after printing. The sheet cutting and conveying unit 6 is also provided with a plurality of conveyance rollers for feeding out the sheet to the next step, and a space for reserving scraps produced by cutting, and includes the sheet trailing edge cutting and separation mechanism according to the present invention.
Print information is recorded on a back surface of the cut sheet, which has been cut for each unit image in the cutter unit 6, by the information recording unit 7, as necessary.
The drying unit 8 heats the sheet printed by the print unit 4, and dries an applied ink in a short time. The drying unit 8 is provided with a heater and also a conveying belt and conveyance rollers for feeding out the sheet to the next step.
The discharging and conveying unit 10 conveys the sheet cut by the sheet cutting and conveying unit 6 and dried by the drying unit 8, and delivers the sheet to the sorter unit 11. The sorter unit 11 sorts the printed sheets for each group as necessary into different trays of the discharge tray 12 and discharges them.
The control unit 13 performs control of the entire printer. The control unit 13 includes a controller 15 equipped with a central processing unit (CPU) 601, a memory, various types of I/O interfaces and a power source. Operation of the printer is controlled based on commands from the controller 15 or an external device 16 such as a host computer connected to the controller 15 via an input/output (I/O) interface.
The conveyance path from printing of the sheet supplied from the sheet supply to discharging into the discharge tray 12 is illustrated with bold lines. The sheet supplied from the sheet supplying unit 1, and processed each by the decurling unit 2, and the skew correction unit 3, is printed on its surface in the print unit 4. The printed sheet is cut to each predetermined unit length set in advance in the sheet cutting and conveying unit 6 via the inspection unit 5. Print information is recorded on the back surface of the cut sheet by the information recording unit 7 as necessary. Then, the cut sheets are conveyed one by one to the drying unit 8 where drying operation is performed. Thereafter, the cut sheets are discharged and stacked on the tray 12 of the sorter unit 11 in sequence via the discharging and conveying unit 10.
The sheet cutting and conveying unit including the sheet trailing edge cutting and separation mechanism according to the present invention, in the printer with the above-described configuration, will be described more in detail.
A load at the time of cutting fluctuates significantly depending on medium conditions or the like, and a direct current (DC) motor is used for the cutter motor 403. A cutter sensor 407 realizes a high-speed move and stop control by detecting positions of the movable blade 402, and causing it to be stopped by a short brake which causes both terminals of the DC motor to be directly coupled in response to a detecting timing. The cutter sensor 407 is arranged so that the movable blade 402 is stopped usually at the top dead center, and when further one wants to cause it to be stopped at the bottom dead center, this can be coped with by adding a similar sensor.
The conveyance unit of the sheets includes conveyance roller pairs including drive rollers that rotate by obtaining power from motors (not illustrated) and driven rollers that rotate freely by being press-contacted by the drive rollers each aligned along a conveying direction. Arrangement spacing of respective conveyance roller pairs are designed to be a little shorter than lengths of a product of which conveyance can be coped with by the apparatus. The sheet shorter than the arrangement spacing of the conveyance roller pairs cannot be conveyed, which accordingly becomes out of specification. As a conveyance assist unit, a guide member of the sheet is arranged between the rollers, but it is unnecessary for descriptions of the present invention, and is not illustrated in
A most-upstream conveyance roller pair RC feeds the continuous sheet at a constant speed into the first cutter C1, and will not change the speed in connection with cutting operation of the first cutter C1, and may be configured not to be included in the sheet cutting and conveying unit, but to be included in the inspection unit as the previous step. A conveyance roller pair R1 is arranged on the upstream side with respect to the first cutter C1. Between the first cutter C1 and the second cutter C2 are arranged conveyance roller pairs R2 and R3. On the downstream of the second cutter C2 are arranged conveyance roller pairs R4, R5, R6, and R7. On the upstream side of R2, R3, R4, R5, R6, and R7 are arranged edge sensors SE2, SE3, SE4, SE5, SE6, and SE7 that can detect edges of the leading edge or the trailing edge of the sheet to be conveyed. In a case where a length of the sheet after being cut becomes large, an edge sensor SE (N) and a conveyance roller pair R(N) are added on the downstream side.
A control program which the CPU 601 should perform is stored in the read only memory (ROM) 603, and the data used when the CPU 601 performs control is stored in the random access memory (RAM) 602. Among the control data, data relating to lengths and cutting positions of sheets as products after cutting is input from an external device 16 to a main body controller 15, and is processed by an image information processing unit 604 within the main body controller 15 and is input into the CPU 601.
The recording medium cutting apparatus according to the present invention relates to the periphery of the second cutter C2 which separates the unwanted portions from the products.
The second cutter C2 is composed of a pair of blades consisting of a fixed blade 401 as a first blade, and a movable blade 402 as a second blade arranged on the upstream upside in the conveying direction of the fixed blade 401. The movable blade 402, one of the pair of blades moves across the conveyance path in a downward direction as a cutting direction, thereby cutting the recording medium.
The conveyance path of the sheet is inclined downwardly in the conveying direction, and the sheet is conveyed from top-right in
A discharge port 415 is used to discharge a portion of the recording medium cut off by the second cutter C2 in midway of the conveyance path. A movable paper guide 412 on the upstream down side is movable to two positions A and B by a driving source (not illustrated), and usually is stopped at the position A. When the movable paper guide 412 moves to the B position, the discharge port 415 is enlarged in the conveying direction.
The cutting and separation operation varies depending on a length of the unwanted portion SHw as a trailing edge side portion of the recording medium. The shortest first unwanted portion length is equivalent to a length shorter than a distance X along the conveying direction from a leading edge of the fixed blade 401 to the leading edge of the movable paper guide 412.
The next longer unwanted portion length is equivalent to a second unwanted portion length. A portion of the unwanted portion SHw can be held by the conveyance unit on the upstream side. The unwanted portion SHw is the portion of the trailing edge side of the recording medium when it is cut by the cutter portion C2. An unwanted portion length separable at this time only needs to be longer than a distance X2 along the conveying direction from the tip of the fixed blade 401 to a nip portion of the conveyance roller pair R3, and it is necessary to make adjustment during image formation as necessary.
Furthermore, the second length is divided into a length non-conveyable by the conveyance unit and a third unwanted portion length conveyable by the conveyance unit. The third unwanted portion length conveyable by the conveyance unit must be longer than a maximum distance between adjacent conveyance roller pairs within the apparatus.
An accommodating unit 416 receives and accommodates the unwanted portions SHw which has been cut and fallen.
The unwanted portion SHw to be conveyed to the downstream side is fed out downwardly while being guided by a vertical surface 401a constituting a guide unit by the surface on the upstream side of the fixed blade 401. To guide the unwanted portion SHw to the outside of the conveyance path, it is useful that the conveying direction of the conveyance roller pair R3, and the surface 401a on the upstream side of the fixed blade 401 serving as the guide surface for guiding the recording medium form a blunt angle. Further, at the same time the conveyance roller pair R4 may be driven to start conveying the product SHc to the next step. Since the conveying direction of the conveyance roller pair R3, and the surface 401a on the upstream side of the fixed blade 401 form a blunt angle, the unwanted portion SHw is downwardly guided and falls, while travel is not obstructed by the fixed blade 401.
In a case where the unwanted portion SHw is the second length, the unwanted portion SHw can be separated downwardly by the method as described above. However, in a case of a third length range in which the unwanted portion becomes longest, depending on capacity limitations of the accommodating unit 416, it is optional to convey the unwanted portion SHw, without operating the movable paper guide 412, after cutting similarly to the product SHc, and to separate the unwanted portion SHw by the sorter unit 11 on a most-downstream side.
In the exemplary embodiment described above, the guide surface 401a is formed by the surface on the upstream side of the fixed blade 401, but it may be configured to integrally fix a member different from the fixed blade 401 to the fixed blade 401.
The arrangement of the second cutter C2 and paper guides 410, 411,412, 413, and 414, and the conveyance roller pairs R3 and R4 is similar to that in the first exemplary embodiment. The conveyance roller pair R3 arranged on the upstream of the second cutter C2 is positioned such that the roller R3b on upside is offset by a distance Yon the downstream side in the conveying direction relative to the roller R3a on downside. More specifically, a center of rotation of the roller R3b on upside is arranged downstream by the distance Y than a center of rotation of the roller R3a on downside, and a common tangent line between the roller R3b on upside and the roller R3a on downside at a nip portion is inclined downwardly relative to the conveying direction. The sheet fed from the conveyance roller pair R3 is pushed by the movable paper guide 412 at the position A and is guided between the blade of the second cutter C2 and the movable paper guide 412. When the movable paper guide 412 moves to the position B, the sheet is actively fed downwardly, and operated similarly to the first exemplary embodiment.
In the above-described exemplary embodiment, the portion of the trailing edge side of the cut off recording medium is guided to the outside of the conveyance path, by forming a guide unit on the blade of the cutter. In a case where the portion of the leading edge side of the recording medium is cut off, the guide unit may be arranged on the downstream side of the cutter, and the portion of the leading edge side of the recording medium to be cut off may be guided toward the outside of the conveyance path by the guide unit. In this case, by guiding the portion of the leading edge side of the recording medium guide which has passed through the cutter before cutting toward the outside of the conveyance path by the guide unit, and cutting it by the cutter, the portion of the leading edge side of the recording medium is caused to fall by the guide unit. When the portion of the leading edge side has fallen, the guide unit is retracted from the conveyance path, a remainder of the recording medium is conveyed downstream through the conveyance path.
In the above-described exemplary embodiments, since the portion of the recording medium which has been cut off to obtain completed product can be guided toward the outside of the conveyance path without depending on only gravity, freedom of apparatus layouts, and enhancement of processing speeds are achieved. Even if a length of the portion to be cut off varies, cutting processing can be performed at a high speed.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.
This application claims priority from Japanese Patent Application No. 2011-028822 filed Feb. 14, 2011, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2011-028822 | Feb 2011 | JP | national |