JPH07257094A - Device for conveying roll paper for plotter - Google Patents

Abstract

PURPOSE:To prevent printing failures from occurring such as void in printing or the like due to the abrupt change of a moisture content of roll paper. CONSTITUTION:Roll paper 16 held by a roll shaft 14 rotatably supported by an airframe of a plotter is drawn along paper guide plates 20, 24 by a pinch roller mechanism 26 to be conveyed to a printing mechanism 22, and print- drawing is effected on the roll paper 16 by means of the printing mechanism 22. After stopping a conveyance of the roll paper, a drawn part 16b of the roll paper 16 is loosened between the roll part of the roll paper 16 and paper guide plates 20.24, thereby preventing abrupt temperature and moisture changes of the roll paper 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll paper transport device for an inkjet or thermal raster plotter.

[0002]

2. Description of the Related Art An ink jet or thermal type raster plotter shown in FIG. 2 is disclosed in JP-A-62-20278.
No. 5 is disclosed. In this plotter, a roll paper 4 supported by a roll shaft 2 is pulled out from 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. It is supplied to a printing mechanism composed of 12 and the printing and printing are performed on the roll paper 4.

[0003]

In the above raster plotter, the portion 4a of the roll paper 4 pulled out from the roll portion 4a is always held in tension between the roll portion 4a and the pinch roller mechanism. Therefore, the boundary A between the portion of the plotter device that is in contact with the air and the portion inside the roll unit that is not in contact with the air are
The water content changes rapidly at the points. That is, during continuous use of the plotter, the air inside the plotter device dries at a high temperature, so that the roll portion 4a of the roll paper is
The inside of the sheet is at the point A, and the part 4b where the roll paper is pulled out
It is in a state where it has changed drastically to a high humidity state. At the start of the plotter, since the air inside the plotter device is in a low temperature and high humidity state, the roll paper 4 is rapidly dried inside the roll portion 4a at the point A. As described above, the rapid change in the water content of the roll paper causes printing defects such as white spots. The present invention aims to solve this problem.

[0004]

[Means for Solving Problems] In order to achieve the above object,
The present invention draws a roll paper supported by a roll shaft rotatably supported by a machine of a plotter along a paper guide plate by a pinch roller mechanism, conveys it to a printing mechanism, and prints an image on a drawing portion of the roll paper. In the roll paper transport device of the plotter configured to perform the above, after the transport of the roll paper is stopped, slack is generated in the roll paper pull-out portion between the roll paper roll portion and the paper guide plate. It is a thing.

[0005]

The slack of the paper in the roll paper pull-out portion between the roll shaft and the paper guide plate prevents a sudden change in temperature and humidity of the roll paper.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 is a schematic explanatory view of the configuration of an inkjet or thermal raster plotter, in which a roll shaft 16 supports a roll paper 16 on the machine body of the plotter. The roll shaft 14 is connected to an output shaft of a motor 18 fixed to the machine body via a power transmission mechanism having an electromagnetic clutch.

At the time of printing, the electromagnetic clutch is disengaged, and the roll shaft 14 is constructed so as to be rotatable against a predetermined frictional force. Reference numeral 20 denotes a lower guide plate for guiding the drawn-out portion of the roll paper 16 to a printing mechanism 22 arranged in the machine body, and an upper guide plate 24 is arranged in parallel to and opposed to the upper guide plate 24 at a predetermined interval.

Reference numeral 26 is a pinch roller mechanism for conveying a sheet, which is composed of a drive roller 30 connected to an output shaft of a motor 28 and a pressure roller 32 which is pressed against the drive roller 30 via the sheet. A plurality of ventilation holes 34 are provided through the guide plates 20 and 24, and the lower guide plate 20 is formed with an extension portion 20a for preventing excessive slack of the paper. The motors 18, 28 and the printing mechanism 22 are connected to the controller.

Next, the operation of this embodiment will be described. At the time of printing, the roll paper 16 is pulled out from the roll portion by the pinch roller mechanism 26, is supplied to the print mechanism 22 via the guide plate 20, and printing is performed here.

When the controller finishes printing, the roll paper 1
When the conveyance of No. 6 is stopped, the controller then turns on the electromagnetic clutch to drive the motor 18 in the forward rotation direction to rotate 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.

As a result, the roll portion 16 of the roll paper 16
The degree of adhesion of the boundary portion A of the sheet a with the pull-out portion 16b becomes loose, and the change in the amount of water between the surface portion of the roll portion 16a and the inner portion in contact with the roll portion 16a changes rapidly at the boundary portion A. In the inner part of the roll part 16a, the peripheral part thereof is adapted to the temperature and humidity of the air outside the roll part 16a with the boundary part A as a reference, and the water content changes gradually. 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 drawer portion 16b of the roll paper 16 so as not to be too slack when the drawer portion of the roll paper 16 is slackened. Excessive slack in the pull-out section 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.

[0013]

Since the present invention is configured as described above, it is possible to prevent the occurrence of printing and defective printing such as white spots during printing by simple control.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a plotter.

FIG. 2 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 2 roll shaft 4 roll paper 6 drive roller 8 pressure roller 10 platen roller 12 print head 14 roll shaft 16 roll paper 18 motor 20 lower guide plate 22 print mechanism 24 upper guide plate 26 print mechanism 28 motor 30 drive roller 32 pressure roller 34 Vents

Claims (1)

[Claims] 1. A roll paper supported on a roll shaft rotatably supported by a machine body of a plotter is pulled out along a paper guide plate by a pinch roller mechanism, conveyed to a printing mechanism, and printed on a roll paper drawer. In the roll paper transport device of the plotter configured to perform the drawing, after the transport of the roll paper is stopped, slack is generated in the drawer portion of the roll paper between the roll portion of the roll paper and the paper guide plate. A plotter roll paper feeder characterized in that