The present invention relates to a medium supply apparatus for supplying a medium which is wound into a roll shape.
A printer featuring a roll sheet guide member provided has been proposed (see patent number 1). In the printer, the roll sheet guide member guides the roll sheet to a roller, the roll sheet being pulled from a roll sheet support part. When performing a printing, the roll sheet guide member is advanced by a driving unit to a advancing position at which a roll sheet path is bent so that the roll sheet comes to contact with the roller for a predetermined length. When not performing the printing, the roller paper guide member is retrieved by the driving unit to a releasing position at which the roller paper is released. In the printer in patent document 1, the roller paper is prevented from having a curved habit (a curved portion) by retrieving the roll sheet guide member when not printing.
[Patent Document 1]
JP Laid Open Patent Publication H10-297043 (e.g., paragraphs 0012-paragraph 0019, FIG. 2)
It is noted that, in the specification, a “retracted position” and a “releasing position” of a tension roller are used for a similar meaning in correspondence with contexts.
However, according to the technique of Patent Document 1, the roll sheet guide member is merely retrieved to the releasing position for releasing the roll sheet, and the roll sheet passed between the roll sheet support part and the roller is held while being curved. It is impossible to avoid that the roll sheet is curved.
The present invention is made to solve the above-described drawback. It aims to provide a medium supply apparatus capable of avoiding a curved habit that affects transportation of a medium wound in a roll shape.
A medium supply apparatus, disclosed in the application, includes a holder that is configured to rotatably support a medium, which is wound in a rolled shape and to be rotated by a drive part, a conveyance part that conveys the medium in a conveyance direction, and is disposed in a downstream side with respect to the holder in the conveyance direction, a tension member that is disposed between the holder and the conveyance part, and contacts to the medium, which is positioned between the holder and the conveyance part, to apply a tension to the medium, a state switching part that has a detection sensor that detects a position of the tension member and switches states of the tension member between two states in correspondence with a detection result by the detection sensor, one state being a fixed state where the tension member is locked such that the tension member is not movable, and the other state being releasing state where the tension members is not locked such that the tension member is movable, a control unit that controls the drive part for the holder, conveyance part, and the state switching part, wherein the tension member is swingable between a first position at which a first corner angle (θ1) is formed and a second position at which a second corner angle (θ2) is formed, the first and second corner angles being determined with two tangent lines formed on the tension member which are seen from a rotational axis view of the holder, one tangent line being at an upstream contact point (UCP) where the medium comes in first contact with the tension member, and the other tangent line being at a downstream contact point (DCP) where the medium, which curves around an outer peripheral of the tension member, departs from the outer peripheral of the tension member, the second corner angle (θ2) being greater than the first corner angle (θ1), the control unit causes the state switching part to switch the state of the tension member to the fixed state in the first position when the medium is supplied, and the control unit causes the state switching part to switch the state of the tension member to the releasing state in the first position when the control unit does not receive an image forming start signal, which is a signal to start an image forming process, for a predetermined period after the conveyance part stops conveying the medium so that the tension medium is moved to the second position as the drive part drives the holder to rotate in an opposite direction to the conveyance direction, and the control unit causes the state switching part to switch the state of the tension member to the fixed state when the tension member reaches the second position.
Also, another medium supply apparatus, which is disclosed in the application, includes a holder that is configured to rotatably support a medium, which is wound in a rolled shape and to be rotated by a drive part, a conveyance part that conveys the medium in a conveyance direction, and is disposed in a downstream side with respect to the holder in the conveyance direction, a medium guide part that has a curved portion, is disposed in a upstream side with the conveyance part in the conveyance direction, a tension member that is disposed between the holder and the medium guide part along the conveyance path and applies a tension to the medium by contacting, the tension member being swingable between a first position and a second position, when the tension member is at the first position, the medium being curved by the curved portion of the medium guide part so that the medium is in a curved shape, seen from a side view of the medium being conveyed, the side view being perpendicular to the conveyance direction and to flat surfaces of the medium, when the tension member is at the second position, the medium not contacting to the curved portion of the medium guide part so that the medium is in a linear shape, seen from the side view of the medium, the tension applied by the tension member being oriented from the second position to the first position, a state switching part that has a detection sensor that detects a position of the tension member and switches states of the tension member between two states in correspondence with a detection result by the detection sensor, one state being a fixed state where the tension member is locked such that the tension member is not movable, and the other state being releasing state where the tension members is not locked such that the tension member is movable, a control unit that controls the drive part for the holder, conveyance part, and the state switching part, wherein the control unit causes the state switching part to switch the state of the tension member to the fixed state in the first position when the medium is conveyed to the downstream side for an image forming process, and the control unit causes the state switching part to switch the state of the tension member to the releasing state in the first position when the control unit does not receive print data for the image forming process for a predetermined period after the conveyance part stops conveying the medium so that the tension medium is moved to the second position as the drive part drives the holder to rotate in an opposite direction to the conveyance direction, and the control unit causes the state switching part to switch the state of the tension member to the fixed state when the tension member reaches the second position.
According to the present invention, it is possible to prevent the curved habit of the medium wound into the roll shape, which affects the transportation.
The roll sheet supply device 100 according to the embodiment feeds a continuous sheet 101a from the roll sheet 101 formed of the continuous sheet (medium) 101a, which is wound in a roll form, and supplies the continuous sheet 101a to the printing device 200, which is an external apparatus. Note that the printing device 200 is an example of the external apparatus, and that the external apparatus is not limited to the printing device 200. In the present application, the roll sheet 101 is configured with a portion wound in a roll form and a portion drawn out from the wound portion in the roll form. The drawn portion is referred to as the “continuous sheet 101a.”
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The roll sheet holder 10 rotates clockwise or counter-clockwise by a rotational driving force generated by a holder drive motor 117 as a driving part. The Roll sheet holder 10 feeds the continuous sheet 101a from the roll sheet 101 which is supported on the roll sheet holder 10 by rotating counterclockwise, which is the first direction in
Further, the roll sheet holder 10, in a state where the leading end 101b of the fed continuous sheet 101a is sandwiched by the conveyance rollers 40, rotates such that the continuous sheet 101a is wound to the rearward (or opposite direction of the conveyance direction E of the continuous sheet 101a), and pulls the continuous sheet 101a rearwardly, and operates so as to provide a tension (hereinafter referred to as “back tension”) to the continuous sheet 101a. The roll sheet holder 10 rewinds the continuous sheet 101a by rotating in the clockwise direction which is the second direction in
When applying the back tension against the continuous sheet 101a, for example, it is preferred not to apply a load, which is the predetermined upper limit value or more (pulling force), to the continuous sheet 101a by a mechanical torque limiter. Further, it is preferred that the upper limit value set in the torque limiter is equal to or larger than the self weight of the tension roller part 20.
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A sheet guide part 401 (or medium guide part) is disposed between the tension roller 25 and the conveyance roller 40 (or nipping point NP) on the medium conveyance path. The sheet guide part has a curved portion along which the sheet is curved and held in the curved shape while the tension roller 25 stays at a first position discussed below. With the structure, a certain tension provided by the tension roller to the sheet is maintained between the conveyance roller and the tension roller in order to enhance the conveyance accuracy. In other words, a steady conveyance of sheet is achieved.
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When the tension roller is positioned at the first position, the sheet, which is between the nipping portion and the tension roller, is in contact with the curved portion of the sheet guide part 401 such that the sheet is curved along the sheet guide part 401. On the other hand, when the tension roller is positioned at the second position, the sheet, which is between the nipping portion and the tension roller, is not in contact with the curved portion of the sheet guide part 401. The sheet between them has a linear shape in the side view. The linear shape of the sheet is illustrated in
At the tension roller shaft 21, a solenoid 119 is provided to hold or release the position of the tension roller part 20 (fixed) (shown in
The bar 22 is fixed to the tension roller support shaft 21. The bar 22 is provided with the spring 24, and the bar 22 is connected to the bar 23 as a support member via the spring 24. At one end of the bar 23, the roller 25 as a contact part is rotatably provided with respect to the bar 23. The continuous sheet 101a contacts to the lower portion of the roller 25. The roller 25 is driven to rotate in correspondence with the conveyance of the continuous sheet 101a.
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<<2>> Operations
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Here, the medium lengths between the roll sheet holder 10 and conveyance roller 40 are more specifically defined by lengths along the conveyance path starting at departing point DP on the roll sheet up to nipping point NP on the conveyance roller 40. The departing point DP is a surface point of the roll sheet where a conveyed continuous sheet departs from the remaining roll sheet, see DPs in
The tension roller part 20 is detected with the upper sensor 31 when reaching the second position.
When the roll sheet holder 10 is rotated in the back feed direction, which is opposite to the conveyance direction E, under a condition where the sheet 101a is nipped by the conveyance roller 40 (or sandwiched by a pair of rollers), the continuous sheet 101a, which has been fed to the conveyance path from the rolled sheet 101, is wound around the roll sheet holder 10. In correspondence with such a motion of the sheet, the tension roller part 20, which is at the first position and contacts to the sheet, is moved upward (or toward the second position). When the tension roller part 20 is detected by the upper sensor 31, it is shut down to energize the solenoid 119 so that the tension roller part 20 is held at the second position (in a lock state).
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By maintaining the second bending angle θ2 close to 180°, the continuous sheet 101a is held in a substantially horizontal state (or no curved state), it is possible to prevent the curling habit from being put of the roll sheet 101 while non-printing period (sheet feeding period). It is noted that the second bending angle θ2 becomes larger as the remaining amount of the rolled paper 101 becomes smaller and the sheet feeding spot (DP) of the continuous sheet 101a (or where a fed sheet departs from the remaining roller sheet) approaches the roll core 102. The second bending angle θ2 is eventually close to 180°.
In order to achieve the above range of the corner angle, the second position of the roller 25 may be on or closer to a connecting line that connects the conveyance roller 40 and a rotational shaft of the holder 10 than the first position. Also, when the first position is located on one side with respect to the connecting line. The second position may be located on the other side with respect to the connecting line.
As the roll sheet is conveyed to the conveyance path, the roll diameter of the roll sheet decreases. In the embodiment, the second bending angle θ2 is designed to be equal to or less than 180° at any time of the sheet conveyance.
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Next, in the process of step S2, the sheet sensor 33 detects a presence of sheet, and, when the lower sensor 32 detects the lowest position (YES in step S2), it proceeds to step S3, the energization of the solenoid 119 (or electrically powering the solenoid) provided in the tension roller support shaft 21 is cut off and locked so that the tension roller part 20 is held at a position at the printing time, which is the lowest position.
Next, it proceeds to step S4, the roll sheet holder 10 which is connected to the holder drive motor 117 rotates to convey the continuous sheet 101a. Then, in the process of step S5, when the sheet end sensor 34 detects the presence (or existence) of sheet (YES in step S5), it proceeds to step S6. In the step, the continuous sheet 101a is conveyed by a predetermined distance and it stops driving rotation of the holder drive motor 117 (see
Then, it proceeds to step S7, as a tension is applied by the tension roller part 20 against the continuous sheet 101a that is drawn too largely by the operator while setting the continuous sheet 101a, while monitoring the detection information from the holder rotation sensor 35, the roll sheet holder 10 which is connected to the holder drive motor 117 is rotated in the backward feed direction, and the winding of the continuous sheet 101a is performed (see
Next, in the process of step S8, when the output state of the holder rotation sensor 35 (detection information) becomes stable (YES in step S8), and it proceeds to step S9. The continuous sheet 101a is determined as fully wound and the rotation of the holder drive motor 117 stops. At this time, a tension by the tension roller part 20 is applied to the continuous sheet 101a, the tension is applied to the continuous sheet 101a that is positioned between the conveyance roller 40 and the roll sheet holder 10 (
Then, it proceeds to step S10, and waits until the print data is received from an upper host (or upper host device) within a predetermined t period. When the print data within the predetermined period is received (YES in step S10), it proceeds to step S11, performing printing by conveying the continuous sheet 101a to the printing device 200. In this embodiment, it starts to count the predetermined period at a timing when the rotation of the holder drive motor 117 stops (or conveyance part stops to convey the medium).
At the printing time, by rotating the roll sheet holder 10 which is connected to the holder drive motor 117 in the back feed direction, unnecessary feeding of the continuous sheet 101a is prevented, which is caused by the conveying of the conveyance roller 40, the supply roller 60, and a conveying mechanism inside the printing device 200. When the printing is finished, the holder drive motor stops driving (see
When the print data is not received within the preset period (NO in step S10), it proceeds to step S12 in
Then, it proceeds to step S13. In order to move the tension roller part 20 at the highest position, which is a retracted position during non-printing (second position), while detection information from the holder rotation sensor 35 and the highest position detection information of the upper sensor 31, the roll sheet holder 10 which is connected to the holder drive motor 117 is rotated in the back feed direction, winding the continuous sheet 101a.
At this time, the roll sheet holder 10 connected to the holder drive motor 117 is rotated in the back feed direction until the upper sensor 31 detects the highest position. The driving force for moving the tension roller part 20 in the upward direction is a tension of the continuous sheet 101a which is meshed with the conveyance roller 40 and is wound and conveyed with the holder drive motor 117.
Next, in the process in step S14, when the upper sensor 31 detects the highest position (YES in step S14), it proceeds to step S15. The energization of the solenoid 119 provided in the tension roller support shaft 21 is shut down, and locked. The tension roller part 20 is held at the highest position that is the retracted position during non-printing.
Then, it proceeds to step S16, the output state of the holder rotation sensor 35 is monitored to make sure if the output state of the holder rotation sensor 35 is constantly changing. When the output state of the holder rotation sensor 35 is stable (YES in step S16), and it proceeds to step S18. It determines that the continuous sheet 101a is wound, and stops the rotation of the holder drive motor 117. At this time, the continuous sheet 101a between the conveyance roller 40 and the roll sheet holder 10 is held in a substantially horizontal state with respect to the tension roller part 20 and in a state where a tension is applied (see
When the output state of the holder rotation sensor 35 is constantly changing (NO in step S16), it determines that the continuous sheet 101a is still being wound. it continues the rotation of the holder drive motor 117 (step S17).
Next, in the processing in step S19, it waits until the print data is received from the upper host (upper host device). When the print data from the upper host is received (YES in step S19), it proceeds to step S20. The solenoid 119 provided in the tension roller support shaft 21 is energized, and unlocked to rotate the tension roller part 20 up and down.
Next, it proceeds to step S21, in order to move the tension roller part 20 to the lowermost position at the printing time, while monitoring the lowest position detection information of the lower sensor 32, it causes the holder drive motor 117 to rotate in the feeding direction of the continuous sheet 101a, and performs the feeding of the continuous sheet 101a.
Next, in the processing in step S22, it keeps rotating the holder drive motor 117 until the lower sensor 32 detects the lowest position. The driving force for moving the tension roller part 20 in the downward direction is a tension of the continuous sheet 101a which is meshed with the conveyance roller 40 and is fed and conveyed by the holder drive motor 117 (see
When the lower sensor 32 detects the lowest position (YES in step S22), it proceeds to step S23 in
Next, in the process of step S24, in order to perform to wind up the slack of the continuous sheet 101a, while monitoring the detection information from the holder rotation sensor 35, the roll sheet holder 10 which is connected to the holder drive motor 117 again rotate in the back feed direction, and to wind the continuous sheet 101a (see
Next, in the process of step S25, it monitors the output state of the holder rotation sensor 35 (detection information) to determine if the output state of the holder rotation sensor 35 is constantly changing. When the output state of the holder rotation sensor 35 is stable (YES in step S25), it proceeds to step S26, determines that the continuous sheet 101a is wound, and stops the rotation of the holder drive motor 117.
Next, in the process of step S27, the printing device 200 which received the supply of the continuous sheet 101a from the roll sheet supply device 100 performs printing on the continuous sheet 101a. After the printing operation is completed, it proceeds to step S10 in
<<3>> Effects
As described above, with the roll sheet supply device 100 according to the embodiment, when print data is not received within a preset waiting period from the upper host, as shown in
With the roll sheet supply device 100 according to the embodiment, the solenoid 119 provided in the tension roller support shaft 21 is configured to hold the position of the tension roller part 20 when the electric power is shut down (or deenergized). Even when the apparatus entirely turns off, the tension roller part 20 does not fall, holding the position. Therefore, when the power to the entire apparatus is turned OFF, it can also continue the effect of preventing the curved habit of the continuous sheet 101a.
Also, based on conventional device in which a tension is always applied to a roll sheet which is fed between a roll sheet support part and a roller by a tension mechanism such as the tension roller or the like, and the conveyance accuracy of the roll sheet is improved by using friction against the tension mechanism, because the tension roller is moved to a releasing position during non-printing period, and a necessary tension is not provided to the paper roll, which is fed between the roll sheet support part and the roller, resulting that the roll sheet is kept in a curved state. Therefore, as the transport interruption time (non-printing period) is longer, the roll sheet is curved more large amount, adversely affecting on the conveyance accuracy of the roll sheet after the conveyance restarts. In contrast, according to the roll sheet supply device 100 of the embodiment, the continuous sheet 101a is held in a substantially straight state (or horizontal to the conveyance path) during a period of which the conveyance sheet 101a is not conveyed, preventing to put the curved habit (curl) to the sheet. In the case where there is conveyance suspension, it can also prevent the conveyance accuracy of the roll sheet 101 from being deteriorated after the conveyance restarts.
In the invention, the first corner angle (θ1) is formed when the tension member (or contact portion 25) is in the first position. The second corner angle (θ2) is formed when the tension member (or contact portion 25) is in the second position. Regardless of its position, these corner angles are defined by two tangent lines. The first tangent line is formed at an upstream contact point where the medium comes in contact with the contact portion 25 first after fed from the rolled sheet. In
Number | Date | Country | Kind |
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2017-037350 | Feb 2017 | JP | national |