JPS6213248B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a paper conveying device that is installed in, for example, a thermal transfer color printer, a color copying machine, etc., which performs overlapping printing by conveying paper back and forth.

[Technical background of the invention and its problems]

In this type of device, the paper may meander when it is transported back and forth, but to prevent this,
For example, as shown in FIG. 1, a sheet of paper P is pinched between two pinch rollers 2, 2 driven by a platen roller 1 and the platen roller 1, and is conveyed while being wrapped around the platen roller 1 whose surface has an elastic layer such as rubber. Methods for doing so are well known. In this case, the pressure between the pinch rollers 2, 2' and the platen roller 1 must be equally distributed in the longitudinal direction at a (pressure per unit length) as shown in the figure. If a difference occurs, the amount of deformation of the elastic layer will be different due to the pressure difference, and as a result, a difference will occur in the paper conveyance distance on both sides, causing the paper P to meander and cause overlap printing position deviation.

However, it is difficult to match the longitudinal pressure between the platen roller 1 and the pinch rollers 2 with considerable precision, and the parts precision is high, resulting in a configuration with a large number of parts. I couldn't figure it out.

In addition, as shown in FIGS. 2 and 3, the paper P
The tip of the platen roller 1 and thermal head 3
In other words, the distance (l ₁ + α) from the printing point A to the pinch roller 2 cannot be printed, and the rear edge of the paper P has the distance from the printing point A to the pinch roller 2' and the distance between the thermal transfer paper 4 and the paper P. This means that a portion corresponding to the sum of (l ₂ +α+l ₃ ) and the distance to separation point B cannot be printed. For example, for _A4 size paper P, the total length is 297 mm, the leading edge P ₁ is 25 mm, and the trailing edge P ₃ is
About 45mm cannot be printed, so the printing range P ₂
had the inconvenience of being extremely short at about 227 mm.

[Purpose of the invention]

The present invention has been made focusing on the above circumstances,
The purpose is to provide a conveyance device which has a relatively simple configuration and is capable of preventing skew of the transferred material.

[Summary of the Invention] In order to achieve the above object, the present invention includes a conveyance means for conveying a transfer material, and a conveyance means provided near the conveyance means to align the transfer material in a direction perpendicular to the conveyance direction. The apparatus includes an alignment means, and causes the transferred material to reciprocate between the transfer section and the alignment means via the conveying means, and aligns the transferred material by the alignment means.

[Embodiments of the invention]

The present invention will be described below with reference to an embodiment shown in FIGS. 4 to 8. In the figure, reference numeral 11 denotes a platen roller, and a thermal head 12 as a recording head is brought into contact with and separated from the platen roller 11. The pressure contact portion between the thermal head 12 and the platen roller 11 is a transfer portion 13, and a pinch roller 14 is provided on the paper discharge side bordering the transfer portion 13, and this pinch roller 14 rolls into contact with the platen roller 11. has been done. Further, an ink ribbon 15 is interposed between the platen roller 11 and the thermal head 12, and this ink ribbon 1
5 is guided and moved by a pair of guide rollers 16, 16. On the other hand, on the supply side of the paper P as a transfer material to the transfer section 13, a pair of feed rollers 1 as a conveyance means are provided.
7, 18 and alignment means 20 are provided.
The pair of feed rollers 18 and 19 are provided so as to be able to move toward and away from each other, and are configured to rotate forward and backward. Further, a detection sensor 19 is provided between the pair of feed rollers 18 and 19 and the platen roller 11.
is provided, and this detection sensor 19 is designed to detect the leading edge and trailing edge of the paper P.
When this detection sensor 19 detects the leading and trailing ends of the paper P, it gives an operating command to the driving sources (not shown) for the pair of feed rollers 17 and 18. In addition, as a result, the above-mentioned feed reroller 1
When the rollers 8 and 19 are rotated, the number of rotations is counted by a counter (not shown), and the distance over which the paper P is fed by the feed rollers 18 and 19 is controlled. That is, the paper P is reciprocated between the printing unit 13 and the alignment means 20 via the feed rollers 18 and 19, and the entire paper P passes through the transfer unit 13 each time during this reciprocation. It's getting old.

Further, the alignment means 20 includes a substrate 21 and an alignment reference plate 22 provided on one side of the substrate 21, and is moved to the other side of the substrate 20 in a direction perpendicular to the conveying direction of the paper P. It has a flexible press plate 23. The pressing plate 23 is rotatably connected to the pressing shaft 24 via a rotating shaft 25, and has a degree of freedom in the direction of arrow DD. The push shaft 24 is moved forward and backward by a drive source (not shown).

Therefore, at the time of transfer, the inclination of the paper P is first aligned by the alignment means 20. That is, the eighth
As shown in the figure, the push shaft of the alignment means 20 is advanced in the direction of the mismark a, and the push plate 23 moves the
As shown by the dotted chain line, one side end of the sheet P in an inclined state is pressed to move it, and the other side end is brought into contact with the alignment reference plate 21. As a result, the paper P is aligned with the alignment reference plate 21, and its inclination is corrected.

After the alignment operation is completed in this way, as shown in FIG.
18 and conveys the paper in the direction of the platen roller 11. At this time, the detection sensor 19 once aligns the leading edge of the paper P, and the exact distance from the detection sensor 19 to the transfer unit 13 is determined by the feed roller 1.
The paper P is conveyed while counting the number of rotations of 7 and 18. Thereafter, the paper P is conveyed by the platen roller 11 and the pinch roller 14 driven by the platen roller 11 while being printed in the transfer section 13, and the entire paper P passes through the transfer section 13.

After printing is completed, as shown in FIG. 6, the thermal head 12 is lowered, the platen roller 11 and the feed rollers 17, 18 are rotated in the opposite direction to the printing direction, and the paper P is conveyed to the alignment means 20. The leading edge of the paper P is detected by the detection sensor 19 again, and the leading edge of the paper P is slightly moved from the detection sensor 19 by the alignment means 2.
0 direction, the platen roller 11 and feed rollers 17, 18 stop rotating, and the paper P
After the paper P is brought to rest, a gap is provided between the feed rollers 17 and 18, and the paper P is aligned again in the state shown in FIG. 4 to perform overlapping printing.

With the above configuration, it is possible to print on the entire surface of the paper P, and after each printing, the paper P is aligned,
Since the paper position is determined by the detection sensor 19, printing is always started in the same state, eliminating the accumulation of skew during paper conveyance, and reliably preventing positional shift in overlapped printing.

[Effects of the Invention] As explained above, in the present invention, during transfer, the material to be transferred is reciprocated between the transfer section and the alignment means via the conveying means, and the material to be transferred is aligned by the alignment means. , it is possible to reliably prevent the shift of the overlapping transfer position and to perform image transfer in a good manner.

[Brief explanation of the drawing]

Figures 1 to 3 are explanatory diagrams showing conventional examples, and Figures 4 to 3 are explanatory diagrams showing conventional examples.
FIG. 8 shows one embodiment of the present invention, FIGS. 4 to 6 are explanatory diagrams showing the operation at the time of overlapping transfer, and FIG.
The figure is a plan view showing the alignment means, and FIG. 8 is an explanatory view showing its operating state. 11...Platen, 12...Recording head (thermal head), P...Transfer material (paper), 17,1
8... Conveyance means (feed roller), 20... Alignment means.

Claims (1)

[Scope of Claims] 1. In an apparatus in which a transfer material is reciprocally conveyed to a transfer portion where a platen and a recording head are in pressure contact with each other to transfer images in an overlapping manner, a conveyance means for conveying the transfer material and a vicinity of the conveyance means. an alignment means for aligning the transferred material in a direction perpendicular to the conveyance direction thereof, the transfer material being transferred between the transfer section and the alignment means via the conveyance means; A conveyance device characterized in that the transfer material is aligned by the alignment means by reciprocating the transfer material. 2. The conveyance device according to claim 1, wherein the transfer material is aligned every time it is reciprocated. 3. The conveyance device according to claim 1 or 2, wherein the position of the transferred material is detected between the conveyance means and the platen roller.