JP3438081B2 - Roll paper transport device for plotter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll paper transport device of a raster plotter of an ink jet type or a thermal type. 2. Description of the Related Art An ink jet or thermal type raster plotter shown in FIG.
No. 5 discloses this. In this plotter, a roll paper 4 supported by a roll shaft 2 is pulled out of a roll portion 4a by a pinch roller mechanism including a driving roller 6 and a pressure roller 8, and the pulled out portion 4b is a platen roller 10 and a print head. 12, where printing and drawing are performed on the roll paper 4. In the above-mentioned raster plotter, the portion 4a of the roll paper 4 pulled out from the roll portion 4a is always kept in tension between the roll portion 4a and the pinch roller mechanism. ing. Therefore, the boundary A between the portion that is in contact with the air in the plotter device and the portion that is not in contact with the air in the plotter device inside the roll portion.
At the point, the water content changes rapidly. That is, during continuous use of the plotter, the air in the plotter device dries at a high temperature, so that the roll portion 4a of the roll paper
Is the part 4b where the roll paper is pulled out from the point A
The state is abruptly changed to a humid state compared to. Further, when the plotter starts, the air in the plotter device is at a low temperature and high humidity, so that the roll paper 4 is rapidly dried inside the roll portion 4a at the point A. As described above, a sudden change in the amount of water in the roll paper causes printing defects such as white spots. An object of the present invention is to solve this problem. [0004] To achieve the above object,
The present invention relates to a pinch roller comprising a driving roller and a pressure roller, wherein a roll paper is mounted on a roll shaft rotatably supported so that a predetermined frictional force is imparted to the body of a plotter. A mechanism pulls out the paper in a fixed direction against a predetermined frictional force along the paper guide plate, rotates the roll shaft forward by this pulling force, conveys the rolled paper to the printing mechanism, and prints on the rolled paper drawer. In the roll paper transport device of the raster plotter, the transport of the roll paper is stopped, and after the transport of the roll paper is stopped, the roll shaft is driven in the normal rotation direction or the drive roller is driven in the reverse direction to form the roll portion of the roll paper. The roll paper drawer is slackened between the roll paper and the guide plate, and the degree of adhesion of the paper at the boundary between the roll paper and the drawer of the roll paper is reduced. The looseness of the paper at the roll paper drawer between the roll shaft and the paper guide plate lowers the degree of adhesion of the paper at the boundary between the roll and the drawer of the roll paper. Prevent humidity changes. Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating the configuration of an inkjet or thermal raster plotter. A roll paper 16 is supported by a roll shaft 14 on the body of the plotter. The roll shaft 14 is connected to an output shaft of a motor 18 fixed to the body via a power transmission mechanism having an electromagnetic clutch. At the time of printing, the electromagnetic clutch is disconnected, and the roll shaft 14 is configured to be rotatable against a predetermined frictional force. Reference numeral 20 denotes a lower guide plate for guiding a drawer of the roll paper 16 to a printing mechanism 22 disposed on the machine body, and an upper guide plate 24 is arranged in parallel with and opposed to the lower guide plate 24 at a predetermined interval. Reference numeral 26 denotes a pinch roller mechanism for conveying a sheet, which comprises a driving roller 30 connected to an output shaft of a motor 28 and a pressing roller 32 pressed against the driving roller 30 via a sheet. The guide plates 20 and 24 are provided with a plurality of ventilation holes 34, and the lower guide plate 20 is formed with an extension portion 20a for preventing the paper from excessively slackening. The motors 18, 28 and the printing mechanism 22 are connected to a controller. Next, the operation of this embodiment will be described. At the time of printing, the roll paper 16 is pulled out of the roll portion by the pinch roller mechanism 26, and is supplied to the printing mechanism 22 via the guide plate 20, where printing is performed. When the printing is completed, the controller
6, the controller turns on the electromagnetic clutch, drives the motor 18 in the normal rotation direction, rotates the roll shaft 14 in the counterclockwise direction in FIG. The portion 16b pulled out from the roll portion 16a is slackened as shown in FIG. Thus, the roll portion 16 of the roll paper 16
a, the degree of adhesion of the boundary portion A with the drawer portion 16b is loosened, and the change in the water content between the surface portion of the roll portion 16a and the inner portion in contact with the roll portion 16a changes abruptly at the boundary portion A. Instead, the portion inside the roll portion 16a has its peripheral portion adapted to the temperature and humidity of the air outside the roll portion 16a with reference to the boundary portion A, and the amount of moisture gradually changes. This prevents the occurrence of printing defects such as white spots during the next printing. The extension portion 20a of the guide plate 20 supports the draw-out portion 16b of the roll paper 16 so that the draw-out portion of the roll paper 16 does not slack when the draw-out portion of the roll paper 16 is slackened. Excessive slack in the drawer of the roll paper 16 causes deformation of the paper. The slack between the roll portion 16a of the roll paper 16 and the paper guide plate 20 may be generated by reversing the drive roller 30. According to the present invention, as described above, it is possible to prevent the occurrence of printing defects, such as printing, such as white spots, at the time of printing and drawing, with simple control.

[Brief description of the drawings] FIG. 1 is a schematic explanatory view of a plotter. FIG. 2 is an explanatory diagram of a conventional technique. [Explanation of symbols] 2 Roll axis 4 Roll paper 6 Drive roller 8 Pressure roller 10 Platen roller 12 Print head 14 Roll axis 16 Roll paper 18 motor 20 Lower guide plate 22 Printing mechanism 24 Upper guide plate 26 Printing mechanism 28 motor 30 Drive roller 32 pressure roller 34 vents

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B43L 13/00 B41J 15/00-15/24

Claims (1)

(1) A roll paper is mounted on a roll shaft rotatably supported so that a predetermined frictional force is applied to the rotation of the body of the plotter, and the roll paper is driven. A pinch roller mechanism composed of a roller and a pressure roller draws out a predetermined direction along a paper guide plate against a predetermined frictional force, and the pulling force rotates the roll shaft forward to convey the roll paper to a printing mechanism. In a raster plotter roll paper transport device that prints images on the roll paper drawer,
After the conveyance of the roll paper is stopped, the roll shaft is driven in the normal rotation direction or the drive roller is driven in the reverse direction to pull out the roll paper between the roll portion of the roll paper and the guide plate. A roll paper transport device for a plotter, wherein slack is generated, and the degree of close contact between the roll paper and the paper at the boundary between the roll portion and the drawer portion is reduced.