JPH02266968A - Paper feed mechanism of printer - Google Patents

Abstract

PURPOSE:To improve the operability of paper feeding by providing a paper- feeding roller with at least two sensors for detecting the starting end of a printing paper and by operating said paper-feeding roller after the outputs of both sensors indicate that there is paper. CONSTITUTION:When a printing paper 3 is fitted to an apparatus, its starting end 3' is detected by respective paper-feeding sensors 11a, 11b. When said printing paper 3 is fitted in parallel with a paper-feeding roller 8 from the beginning, two paper-detecting sensors 11a and 11b detect the starting end 3' at the same time. However, when said paper is fitted in an inclined state, one paper-detecting sensor 11a first detects the starting end 3'. If the printing paper 3 is pushed up further, the right side of said starting end 3' comes to be detected by the paper-detecting sensor 11b. When said both paper-detecting sensors 11a, 11b detect the printing paper 3, the starting end 3' and paper-feeding roller 8 are in parallel with each other. That is, the AND of 'there is paper' signal of both paper-detecting sensors 11a and 11b is taken to start driving of said paper- feeding roller 8. Thus, said printing paper 3 is pulled up without inclination.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an automatic sheet feeding mechanism for printing paper in a printing device using continuous paper.

[Background of the invention]

The configuration of a printing device to which the present invention is applied and problems occurring regarding automatic paper feeding of printing paper will be explained with reference to FIGS. 3 and 4.

The printing device described below forms characters, figures, etc. in a dot matrix while reciprocating a hammer bank 1, which is equipped with a plurality of printing hammers (not shown), in the left and right direction using a reciprocating means (not shown). belongs to. As another type of printing device, for example, there is a printing device that uses an endless band of thin steel plate called a print band with characters formed thereon as a type carrier, and of course the same thing occurs with this type of printing device. That applies. In addition, 0 or more, which is the same for printing devices generally called serial dot printers, are impact type printing devices, but the same applies to non-impact type printing devices such as inkjet type or laser type.

On the front surface of the hammer bank 1, there are platens 2 arranged in parallel at predetermined intervals and constitute a printing mechanism section. The printing paper 3 passes through a vapor guide 4 between a hammer bank 1 and a platen 2, and is applied to a pair of paper feed tractors 5. The paper feed tractor 5 is driven by a belt 7 by a paper feed motor 6.
The printing paper 3 is sent by being driven through the printer.

In some printing apparatuses having the above configuration, a paper feed roller 8 is provided below the platen 2 for the purpose of improving operability. In a printing device without a paper feed roller 8, when loading a new printing paper 3, the printing paper 3 is manually fed from the vapor guide 4, and after the starting edge of the printing paper 3 appears above the platen 2, the printing paper 3 is manually fed in. The operations associated with mounting the printing paper 3, such as pulling it up and mounting it on the paper feed tractor 5, may seem simple, but are extremely difficult because the operations must be done in a bent or half-slumped posture. In order to make this operation as easy as possible, a paper feed roller 8 is disposed below the platen 2 to pull up the printing paper 3 by a predetermined amount. By doing this, the amount of printing paper 3 to be manually fed becomes extremely small, making the operation easier.

The paper feed roller 8 is driven by a motor 9 via a belt 10. In order to detect the starting edge 3' of the printing paper 3, a starting edge detection sensor 11 is provided on the left side (1st digit side) of the paper feed roller 8. The mountain range provided on the left side is because printing sheets 3 of various widths are used, and narrower printing sheets 3 are also set with the one-digit side (left side) as a reference.

The printing apparatus having the paper feeding configuration described above has the following problems.

The printing paper 3 is manually fed to the paper feeding roller 8, and the starting edge 3' of the printing paper 3 is not necessarily fed parallel to the paper feeding roller 8.As shown in FIG. 3 is generally fed in an inclined state. When the paper feed roller 8 is driven in this state, the printing paper 3 is fed in an inclined state as shown by the two-dot chain line, so it hits the side of the vapor guide (not shown) on the way and becomes jammed. Since it is difficult to pull up the paper 3, the paper 3 is returned to its original position and reloaded, but at that time, the leading edge 3' becomes bent or wrinkled and cannot be loaded normally. Then, the first page is torn up and thrown away, resulting in waste. Devices designed to improve operability become meaningless.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to improve the operability of paper feeding in this type of printing device.

[Summary of the invention]

The present invention focuses on the fact that the paper feeding roller operates even when the printing paper does not enter the paper feeding roller parallel to the paper feeding roller, making it difficult to load the printing paper. The paper feed roller is devised to operate after detecting whether the paper is parallel to the rollers.

(Embodiment of the Invention) An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

Since the parts other than the parts described below are the same as those described in the prior art, the description will be omitted.

A paper detection sensor 11b is arranged near the center of the paper feed roller 8. On the left side of the paper feed roller 8, there is a paper detection sensor lla as in the conventional case. When the printing paper 3 is loaded in this state, its starting edge 3' is detected by each paper feed sensor lla, llb.

FIG. 2 is a timing chart showing the detected state. If the printing paper 3 is installed parallel to the paper feed roller 8 from the beginning, two paper detection sensors lla and llb are activated.
detects the starting edge 3' at the same time, but if the paper is installed in an inclined state, one of the paper detection sensors lla detects the starting edge 3' first. In this state, the starting end 3' hits the paper feed roller 8 and cannot move forward. As the printing paper 3 is further pushed up, the right side of the starting edge 3' comes to be detected by the paper detection sensor llb. When both paper side ratio sensors 1la11b detect the printing paper 3, its starting edge 3' and the paper feed roller 8 are parallel to each other. Namely.

Paper presence signals from both paper detection sensors lla and llb are ANDed to start driving the paper feed roller 8. By doing this, printing paper 3
Since the paper can be pulled up without tilting, there will be no jamming caused by the paper getting caught on the paper guide.

In the embodiment described above, the paper detection sensors 11 are provided at two locations, one on the left side and the other near the center, but in order to handle various types of paper with different @ marks, three may be provided in the middle.

The above embodiment also has the following operability problems. - The distance between hammer bank 1 and platen 2 in the membrane is 0.3
5 to 0.41, which is very narrow. Even if you try to pass the printing paper 3 through this space, it will not pass. Therefore, when installing the printing paper 3, first make sure to widen the above-mentioned space sufficiently. perform operations. This is called platen opening.

If the paper feeding mechanism is operated without operating the platen, the leading edge 3' of the printing paper 3 will get caught between the hammer bank 1 and the platen 2, resulting in a jam.

In order to prevent this operational error, when the paper detection sensor 11 detects the printing paper 3, it is configured to detect whether or not the platen 2 is open.If the platen 2 is not open, an alarm is issued and the operator If the printer is equipped with a mechanism that automatically opens and closes the platen 2, the platen 2 will be opened by detecting the printing paper 3 and then activating the platen opening/closing mechanism. After that, the paper feed roller 8 is operated. By using such a sequence, the above-mentioned erroneous operation can be prevented.

After loading the printing paper 3, printing is performed, but eventually the printing paper 3 runs out. At this time, in order to detect the end of the printing paper 3, what is generally called an end switch is provided. It is also possible to use the paper detection sensor 11 described above as a termination switch.

〔Effect of the invention〕

According to the present invention, at least two print paper starting edge detection sensors are provided at the paper feed roller, and the paper feed roller is operated only after the output of the sensor indicates that paper is present. The paper can be pulled up without tilting, preventing paper jams caused by getting caught in the paper guide, and improving operability.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of a paper feeding device of a printing device according to the present invention, FIG. 2 is a timing chart showing a paper detection state of a paper detection sensor, and FIG. 3 is a front view of a conventional technology.
FIG. 4 is a sectional view. In the figure, 8 is a paper feed roller, and lla and llb are paper side ratio sensors. Name of patent applicant Hitachi Koki Co., Ltd.

Claims (4)

[Claims] (1) A printing mechanism unit for printing characters, figures, etc. on printing paper, at least a pair of paper feed tractors for feeding the printing paper, and a mechanism located below the printing mechanism unit for pulling up the printing paper. In the printing device having a paper feed roller, a plurality of the prints are arranged at intervals of such an extent that it can be detected that at least the starting edge of the printing paper and the paper feed roller are parallel to each other in the longitudinal direction of the paper feed roller. A paper feed mechanism for a printing device, characterized in that it is provided with a detector for detecting the starting edge of paper. (2) When the printing paper is attached, the plurality of paper detectors detect the printing paper, and then the paper feed roller is driven to feed the printing paper by a predetermined amount. Paper feed mechanism of the listed printing device. (3) The printing mechanism section has a plurality of printing hammers and a platen for supporting the printing force of the printing hammers, and a platen opening/closing mechanism for changing the distance between the platen and the printing hammers. and a driving means for driving the platen opening/closing mechanism, and after the paper detector detects the starting edge of the printing paper, the platen opening/closing mechanism sets the platen to the open position, and then the platen is moved to the open position. 2. A paper feed mechanism for a printing device according to claim 1, wherein the paper feeding mechanism is adapted to feed the printing paper by a predetermined amount. (4) A paper feeding mechanism for a printing device according to claim 1, wherein the paper detector detects the end of the printing paper.