JPH028921Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Industrial application field This invention is based on continuous paper (CONTINUOUS paper).
This product relates to a device for preventing print misalignment, paper wrinkling, and distortion in a printing paper feeding device for printers that uses a tractor to feed paper (FORM) to a printing station and then pull it up with a pair of rollers after passing through the printing station. be.

B. Prior Art There is currently an apparatus that transfers and feeds continuous paper from a tractor to a pair of rollers. However, an inexpensive and effective technique for resolving the stress that occurs in continuous paper that is delivered and fed between different feeding means such as a tractor and a pair of rollers has not yet been developed.

C. Problems to be solved by the invention In the feeding method where continuous paper is fed from below to the printing station by a tractor and then pulled up by a pair of rollers after passing through the printing station, (1) the feed amount of each of the tractor and roller pair is Due to factors such as slight differences (2) resistance of the roller pair to the paper (3) slight skew (SKEW) in the roller pair, there is a slight difference between the tractor and the roller pair.
Stress gradually accumulates on the paper. If the strength of the paper itself is exceeded, the paper may become wrinkled or distorted, or in the case of multi-leaf continuous paper for copying, the first sheet may bulge. cause problems. For example, even if the bulge on the first sheet of paper is very small per page, after 5 to 10 pages have been fed, the amount accumulates and reaches a non-negligible amount.

D. Means for solving the problem Every time the continuous paper fed from the tractor side and passed through the printing station is pulled up by the pull-up roller pair 7 for a predetermined number of pages (for example, one page to several pages), the pull-up roller pair 7 is pulled up. 7 pinch roller 7
b is lifted and momentarily separated from the roller 7a.

As a result, the lower part momentarily releases the upper part of the continuous paper, which is still restrained by the tractor, and its own rigidity causes the upper part to return to its original shape. This dissipates the stress created on the continuous paper and prevents the accumulation of wrinkles, warps, and bulges.

E. Example The printer schematically shown in the longitudinal cross-sectional view of FIG.
A tractor 2, a pair of auxiliary rollers 3, a printing station 4, a stopper 5, a sensor 6, and a pair of pulling rollers 7 are provided along the paper feeding line 1. The pulling roller pair 7 is composed of a feeding roller 7a and a pinch roller 7b.

The tractor 2 has a series of pins 21 that engage with feed holes provided on both side edges of the continuous paper 10, and a paper press plate 22 that is hinged to the main body of the tractor so as to be openable and closable. The auxiliary roller pair 3 includes a feeding roller 3a and a pinch roller 3b. The pinch roller 3b is pushed down toward the feed roller 3a and remains engaged until the upper end of the continuous paper is bitten by the pair of pull-up rollers 7 (feeding a single piece of paper, i.e., a cut form). (times always mesh). The stopper 5 is for aligning (horizontally) when inserting a single piece of paper, and is retracted below the paper feed line 1 when inserting continuous paper. When the upper end of the continuous paper is bitten by the pull-up roller pair 7, the auxiliary roller pair 3 is opened by releasing the pinch roller 3b. The continuous paper 10 fed by the tractor 2 passes between the platen 4a and the print head 4b that constitute the print station 4, and is pulled up by the pair of pulling rollers 7.
(See Figure 1).

The platen 4a may be roll-shaped, flat plate-shaped, or any other arbitrary shape. In order to take up the slack in the continuous paper, the pair of pull-up rollers 7 feeds the continuous paper at a speed slightly faster than that of the tractor 2 (for example, about +0.2%).

When continuous paper is continued to be fed in the state shown in Fig. 1 (see the schematic diagram in Fig. 2A), the tractor 2 (engages with the feed holes provided on both side edges of the paper and feeds it).
Misalignment and distortion caused by the difference in the feeding mode between the pair of rollers (which feed the paper by engaging with the central portion thereof), and contradictions caused by the difference in speed accumulate on the paper itself in the form of stress. As a result, an abnormally large tension is generated in the paper, which damages the feed holes and causes sag, which in turn causes the paper to deviate from the ruled lines of the format, causing misalignment of the print position. Accumulation of misalignment can also cause wrinkles on the paper surface, making the print unclear or distorted. In the case of multi-leaf continuous paper for copying, the first sheet of paper swells, causing defective prints.

Therefore, every time continuous paper is fed by a predetermined amount (for example, one page to several pages), the pinch roller 3b of the auxiliary roller pair 3 is pressed in the direction of the feeding roller 3a (see FIG. 2B), and then the roller pair 7 pinch roller 7b
momentarily (for example, less than 1 second) (2nd C
Figure 2B) and immediately re-engaged (Figure 2B). During that moment, the continuous paper returns to its original shape due to its own rigidity, releasing stress. Thereafter, the pinch roller 3b is released (FIG. 2A) to continue the next feeding. As a means for releasing, any ordinary pinch roller engagement and release mechanism can be used.

The method for determining when the pinch rollers 7b and 3b should be alternately engaged and released from the respective feeding rollers 7a and 3a, that is, when the scheduled number of pages of continuous paper has been fed, is determined by the printer. The paper length information stored in the control circuit may be compared with the feeding amount by the tractor 2, or the actual number of pages passed as detected by the sensor 6 provided in FIG. 1 may be selected as appropriate.

It is possible to arbitrarily select whether the pinch rollers 7b and 3b are alternately engaged and disengaged by temporarily stopping paper feeding or by continuous feeding, but the former is easier and cheaper to implement. .

The embodiment shown in FIG. 1 shows an example of a printer that can selectively use either continuous paper or single-piece paper, but in the case of a printer exclusively for continuous paper, the upper end of the tractor 2 should be brought close to the printing station 4. Therefore, the auxiliary roller pair 3 may be omitted. In that case, it is sufficient to engage and release only the pinch roller 7b.

F. Effects of the invention When we conducted feeding experiments on continuous paper using an actual printer, we found that stress did not accumulate on the continuous paper even after several hundred pages were fed. It was fed normally without any inconvenience.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS. 2A to 2C are illustrations of states in which the pinch rollers are alternately engaged and released according to the present invention. DESCRIPTION OF SYMBOLS 1... Paper feed line, 2... Tractor, 3... Auxiliary roller pair, 4a... Platen, 4b... Print head, 5... Stopper, 6... Sensor, 7... Pull-up roller pair, 10 ...Continuous paper.

Claims (1)

[Scope of Claim for Utility Model Registration] A continuous paper feeding device that feeds continuous paper to a printing station using a tractor and pulls it up with a pair of rollers, comprising a feeding roller that constitutes the pair of rollers that bite and pull the continuous paper; A pinch roller is disposed on a paper feed line after the continuous paper passes the printing station, and pinches the continuous paper every time at least one page of the continuous paper passes the printing station. A continuous paper feeding device characterized by instantaneously disengaging a pair of pull-up rollers and re-engaging them.