Patent Application
20130272766
Embodiments described herein relate generally to a core holding structure and a printer.
In the field of printers, there is conventionally known a core holding structure in which a roll-shaped core on which a strip-shaped material such as an ink ribbon is wound is held by a rotationally driven take-up shaft.
In the conventional printers, it is desirable to hold the core and prevent any idle rotation of the core when rotating the take-up shaft and winding the strip-shaped material around the core. It is also desirable that the core can be easily detachably mounted to the take-up shaft.
According to one embodiment, a core holding structure includes a shaft portion to which a core for winding thereon a strip-shaped material is inserted and by which the core is rotationally driven. A roller is provided on an outer circumferential surface of the shaft portion. The roller is configured to make contact with an inner circumferential surface of the core inserted to the shaft portion and rotate in a direction in which the core is attached to or removed from the shaft portion. The core holding structure further includes an elastic member configured to hold the roller and bias the roller radially outwards from the shaft portion when pressed toward the surface of the shaft portion.
A core holding structure and a printer according to embodiments will now be described in detail with reference to the accompanying drawings. The following description is directed to an application of embodiments to a thermal printer for performing printing on a paper through the use of an ink ribbon which is wound around a core held by a core holding structure.
As shown in
The paper roll holding shaft 3 holds the paper roll 11 formed by winding a strip-shaped paper 2, so that the paper roll 11 can rotate about an axis perpendicular to the plan view of
The conveying roller 4, the platen roller 5, the supply shaft 7 and the take-up shaft 8 are rotationally driven by motors (not shown). The conveying roller 4 is arranged at the upstream side of the printing unit 12 and the platen roller 5. The pinch roller block 10 includes a pinch roller (not shown) arranged above and near the conveying roller 4 in a parallel relationship with the conveying roller 4. The pinch roller is biased toward the conveying roller 4 under an appropriate biasing force. The strip-shaped paper 2 is interposed between the conveying roller 4 and the pinch roller and is conveyed by the rotation of the conveying roller 4. In the present embodiment, the conveying roller 4, the platen roller 5, the motors (not shown), the motor controller (not shown) and the pinch roller block 10 make up a conveying mechanism.
The supply shaft 7 or the take-up shaft 8 is a rotationally-driven shaft portion to which a ribbon roll 13 is fitted (the details of which will be described later). The ribbon roll 13 is formed by winding a strip-shaped material such as an ink ribbon 6 on a core 131. In the present embodiment, the core 131 is formed into a substantially cylindrical shape having a generally circular cross section. Alternatively, the core 131 may have a cross section of regular octagon shape or other cross-sectional shapes.
A ribbon roll 13 formed by winding an ink ribbon 6 on a core 131 is inserted and set to the supply shaft 7. Another core 131 for winding thereon the ink ribbon 6, which is drawn from the ribbon roll 13 inserted to the supply shaft 7, is inserted and set to the take-up shaft 8. Upon rotation of the take-up shaft 8 driven by a motor, the ink ribbon 6 is drawn from the ribbon roll 13 set to the supply shaft 7 and is wound on the core 131 set to the take-up shaft 8.
When supplied from the supply shaft 7 and taken up by the take-up shaft 8, the ink ribbon 6 and the strip-shaped paper 2 are interposed between the thermal head 9a of the printing block 9 and the platen roller 5. While the ink ribbon 6 is interposed between the thermal head 9a and the platen roller 5, the ink of the ink ribbon 6 is melted or sublimed as the thermal head 9a is heated. Consequently, specified patterns (e.g., text characters, numerals, barcodes or figures) are transferred to and printed on the inner surface 2a of the strip-shaped paper 2. In the present embodiment, the thermal head 9a and the platen roller 5 make up a printing unit 12 functioning as a printing mechanism for performing printing with the ink ribbon 6 drawn from the rotationally-driven core 131.
The following is a description on a more detailed configuration of the supply shaft 7 or the take-up shaft 8.
Referring to
More specifically, the leaf spring 101 is arranged on the outer circumferential surface 100 to extend in a width direction WD of the supply shaft 7 or the take-up shaft 8. The two opposite ends of the leaf spring 101 are fixed to the outer circumferential surface 100 by fasteners 103. The leaf spring 101 includes a raised portion 110 formed over a specified length of the leaf spring 101. The raised portion 101 is configured to be biased radially outwards from the shaft 7 or 8 when it is pressed toward to the shaft 7 or 8.
Plural pairs of bent portions 111, each of which is bent substantially in a vertical direction toward the outer circumferential surface 100, are formed in the raised portion 110 at specified intervals along the width direction WD. In particular, each pair of bent portions 111 is positioned at the front and rear sides of the raised portion 110 when it is viewed in
The rollers 102 partially protrude radially outwards from the raised portion 110 through holes 113 formed in the raised portion 110, in which the holes are positioned in alignment with the bent portions 111. Accordingly, when the core 131 is attached to or detached from the supply shaft 7 or the take-up shaft 8, the portions of the rollers 102 protruding from the raised portion 110 make contact with the inner circumferential surface of the core 131, such that the rollers 102 can be rotated (or driven) in conjunction with the movement of the core 131. The height of the raised portion 110 with respect to the outer circumferential surface 100 is determined such that, when the core 131 is inserted to the supply shaft 7 or the take-up shaft 8, the rollers 102 do not make contact with the surface of the outer circumferential surface 100.
Therefore, as noted in
The core 131 fitted to the supply shaft 7 or the take-up shaft 8 is supported by the rollers 102 pushed radially outwards by the biasing force of the leaf spring 101. As shown in
While the present embodiment has been described by taking as an example a configuration in which one leaf spring 101 is provided on the outer circumferential surface 100, a plurality of leaf springs 101 may be arranged on the outer circumferential surface 100. For example, another leaf spring having a plurality of rollers may be provided at the opposite side across the shaft axis from the leaf spring 101 shown in
While the present embodiment has been described by taking as an example a configuration in which a plurality of rollers 102 are provided in the leaf spring 101, the present disclosure is not limited thereto. Alternatively, only one roller may be provided in the leaf spring 101.
In the present embodiment, both the supply shaft 7 and the take-up shaft 8 are provided with the core holding structure. However, only the take-up shaft 8 may be provided with the core holding structure if the supply shaft 7 and the take-up shaft 8 are rotationally driven only in the direction in which the ink ribbon 6 is drawn from the supply shaft 7.
In the present embodiment, the supply shaft 7 and the take-up shaft 8 for holding the ribbon roll 13 formed by winding the ink ribbon 6 are provided with the core holding structure. However, the paper roll holding shaft 3 for holding the paper roll 11 formed by winding the strip-shaped paper 2 as a strip-shaped material may also be provided with the core holding structure. For example, in the configuration in which the paper roll holding shaft 3 is rotationally driven by a motor to rewind the unwound strip-shaped paper 2, the paper roll holding shaft 3 may be provided with the core holding structure described above.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel core holding structure and printer described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
