JPS60196382A - Paper feeder for printer - Google Patents

Abstract

PURPOSE:To enable to prevent frictional load in feeding a paper from being increased, even when using a thicker paper, by a construction wherein a plurality of paper guides are provided so that the curvature of a printing paper differs depending on each of the guides, and a guide extension part is provided on the inlet side of the lower one of the guides. CONSTITUTION:Other than a paper guide 16 for ordinary papers which is provided at an upper part, a paper guide 20 for thick papers is provided at a lower part so that the curvature of the printing paper in feeding the paper differs depending on each of the guides (the curvature is smaller for the guide 20). Accordingly, when using a thick paper, the paper is passed through the lower guide 20 to a position between a feeding roller 14 and pinch rollers 14B, whereby it is possible to prevent the pressure and frictional forces exerted on the paper being passed from being increased and to prevent unsatisfactory actions, residual curl or the like from being generated. In addition, since the guide extension part is detachably provided on the inlet side of the guide 20, a thick paper can be easily inserted. Further, since a rear part of the printer is supported by bulking when fitting it, the curvature can be made sufficiently small, without increasing the size of the printer itself.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a paper feeding device for a printing machine such as a printer, a copying machine, or a facsimile machine, and more particularly to the structure of a paper guide portion that guides printing paper to a paper feeding roller.

[Prior art]

Inside each of the above-mentioned printing machines, there is a paper feeding device consisting of a feed roller for feeding the printing paper and a paper guide for guiding the printing paper to the outer periphery of the feeding roller. A mechanism is provided in which the inserted printing paper is brought into contact with the outer periphery of the feed roller, and is caused to pass through the print head (including recording and reproducing heads) by driving rotation of the feed roller.

Conventional paper feeding devices of this type generally have one paper guide, that is, one paper guide that runs from an insertion opening provided on the top surface of the printing machine to an internal feeding roller, and the printing paper fed out from the feeding roller. The paper was turned upward and guided to the printing section, and the paper after printing was taken out from a discharge port provided on the top of the printing machine.

That is, in the conventional paper feeding device, one insertion port and one discharge port for printing paper are provided on the top surface of the printing machine.
During paper feeding, the direction of the printing paper is reversed on the peripheral surface of the feeding roller, so the curvature of the printing paper from the paper guide is increased.

For this reason, the paper feed operation for general paper with a thickness of about 40μ to 100μ is smooth, but for paper with a thickness of about 200μ to 300μ (
When feeding thick paper (of the same size as Fi), the operation becomes unsmooth and, in some cases, it becomes impossible to feed the paper.

In other words, the stiffness of paper is approximately proportional to the third power of its thickness, and when stiff cardboard is fed with the same large curvature as regular paper, it rubs against the paper guide or paper path with a strong force, causing a frictional load. The problem was that the paper became sluggish and paper could not be fed.

Another drawback was that curls remained on the cardboard after printing.

Furthermore, in the structure of the conventional paper feeding device, if an attempt was made to reduce the curvature of the paper feeding path in order to eliminate the above-mentioned drawbacks, there was a problem in that the printing machine would become larger, which would go against the demand for reduction in size and weight.

〔the purpose〕

An object of the present invention is to provide a paper feeding device for a printing machine that eliminates the drawbacks of the conventional paper feeding device and allows normal paper feeding operation without increasing frictional load even when thick paper is used as printing paper. The goal is to provide the following.

[Summary]

In the present invention, paper guides are provided at least at two locations, at the top and bottom of the printing machine, and are arranged so that the curvature of the printing paper from the paper guide during paper feeding is smaller in the lower paper guide than in the upper paper guide. In addition, the above object is achieved by providing a guide extension at the entrance of the lower paper guide.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where an embodiment of the present invention is applied to a thermal transfer printer will be described below with reference to FIGS. 1 and 2.

In FIGS. 1 and 2, the printing machine has a structure in which a printing machine main body 1 is housed and installed in exterior cases 2A and 2B.

The frame 3 of the printing machine body 1 has a horizontal direction (scanning direction).
The main functional parts include a printing mechanism that prints on the printing paper 4 while moving, a paper feeding mechanism that guides the printing paper 4 and feeds it in the line feed direction, and a control mechanism that controls these.

The frame 3 is provided with a carrier shaft 5 extending in the left-right direction, and a carrier 6 is supported on the carrier shaft so as to be movable in the left-right direction (scanning direction). The carrier 6 is driven in the left-right direction by a pulse motor (not shown) or the like via a pulley 7 and a drive belt 8, and is controlled in that direction.

An ink ribbon cassette 9 is mounted on the carrier 6, and is driven in synchronization with the movement of the carrier in the scanning direction to feed an ink ribbon 10 for transfer to the printing section.

Further, a thermal print head 12 is swingably supported on a head shaft 11 provided on the carrier 6, and the print head is placed between a print position where pressure WG is applied to the print paper 4 and a head-up position where it is separated from this. is driven by.

A platen 13 extending left and right is attached to the printing machine main body 1 or its frame 3 at a position facing the print head 12, and a printing paper 4 and an ink ribbon 10 are inserted between the platen and the print head 12. At the same time, thermal transfer printing is performed by driving the print head while these are in pressure contact.

A feed roller 14 is provided below the platen 13 for feeding the printing paper 4 in the line feed direction. A pinch roller 15A% 15B is in contact with the circumferential surface of this feed roller. In the illustrated example, the pair of pinch rollers 15A and 115B are supported at a predetermined interval below the feed roller 14 so as to follow and rotate when the feed roller is driven.

A paper guide 16 for general paper is provided that extends from the rear upper part of the feed roller 14 to the lower side of the feed roller. The printing paper coming in from the paper insertion port 1γ is guided toward the circumferential surface of the feed roller 14.

On the other hand, a paper outlet 18 is provided on the top surface of the printing machine above the print head 12 (or platen 13) for discharging the print paper after printing.

Therefore, the printing paper 4 inserted from the pattern paper insertion slot 17 is moved to the feed roller 14 by the paper guide 16 for several papers, and in response to the rotation of the feed roller, the pair of pinch rollers 15A, 15B, and after being turned upward on the circumferential surface of the feed roller 14, the guide plate 19f provided as necessary: the printing section (between the print head 12 and the platen 13). After being printed, the paper is discharged upward from the paper outlet 18.

In the illustrated printing machine, the paper guide 16 for the -number of papers is
In addition, a paper guide 20 for thick paper is provided which extends from the lower part of the printing area toward the feed roller 14. This paper guide 20 for thick paper has a pair of pinch rollers 15 as shown in the figure.
The printing paper 4 is arranged so as to pass only through one of the pinch rollers A and 15B (the downstream pinch roller 15B),
Therefore, the paper path is the paper guide 16 for the -number of papers.
The passage is arranged to merge between the pair of pinch rollers 15A and 15B.

The inlet (insertion port) 21 of the paper guide 20 for thick paper is located at the lower part of the printing machine (in the illustrated example, at a position near the rear of the lower part).

The contact feldspar on the circumferential surface of the feed roller 14 is different between the printing paper inserted through the paper guide 16 for several papers and the printing paper inserted from the paper guide 20 for thick paper, and the former has a relatively long length. The thicker the contact, the greater the degree of direction change, whereas the latter has a smaller contact length, so the degree of direction change is small (or in some cases, no direction change).
ing.

In this way, with the paper guide 16 provided at the top of the printing machine and the paper guide 20 provided at the bottom, the curvature of the printing paper 4 from the paper guide during paper feeding is greater than the paper guide 16 for general paper at the top. Although it is relatively large when used, it is arranged so that it is relatively small when the lower paper guide 20 for cardboard is used as a box.

Additionally, a guide extension 22 is provided on the entrance side of the paper guide for thick paper, that is, the lower paper guide 20, to facilitate insertion of the printing paper 4. In the illustrated example, the paper guide 20 is provided within the printer 1 and the guide extension 2
2 is detachably attached to the outer case 2 B 11t11. The guide extension 22 is provided at the lower part of the back of the printing machine, and has a shape into which printing paper is inserted from the back, ie, an insertion opening 23 opens at the back.

Furthermore, feet 24 for supporting the printing machine are provided on the bottom of the guide extension 22, and when the guide extension is used (attached), the rear part of the printing machine is raised and the position of the insertion 23 is raised. This facilitates the work of inserting the printing paper from the top and increases the degree of freedom in designing the guide extension part 22.

Note that reference numeral 25 indicates a rear leg that supports the printing machine when the guide extension 22 is removed.

According to the embodiment described above, the paper guide 16 for general paper is provided in the upper part, and the paper guide 2 for thick paper is provided in the lower part 81 (
0, and the curvature of the printing paper 4 from the paper guide during paper feeding is arranged so that the lower paper guide 20 is smaller than the upper paper guide 16, so when using thick and stiff printing paper. can be inserted through the lower paper guide 20, thereby suppressing an increase in frictional load due to friction with the paper guide, and allowing smooth paper feeding operation. It is also possible to prevent curls from remaining on the paper after printing.

Furthermore, a guide extension 2 is provided on the entrance side of the lower paper guide 20.
2 so that it can be inserted from the back of the printing machine, it is possible to easily insert cardboard from the lower paper guide 20.

Furthermore, since the guide extension part 22 is made detachable and has a structure in which the rear part of the printing machine is raised and supported when attached, the curvature of the printing paper can be made sufficiently small without increasing the size of the printing machine itself. This makes it possible to more easily and reliably insert cardboard from the bottom, thereby providing a paper feeding device.

In addition, in the illustrated embodiment, the upper paper guide 16 for general paper is
Two paper guides are provided: and a kite guide 20 for thick paper at the bottom.This means that three or more paper guides are provided and arranged so that the curvature of the printing paper in each is different, and the thickness of the printing paper is adjusted accordingly. It is also possible to configure such a structure that these three or more paper guides can be used appropriately depending on the situation.

Further, in the illustrated example, the guide passage 22 is detachably installed, but it may also be installed in a fixed manner. Furthermore, it is also possible to attach it to the printing machine main body 1 instead of attaching it to the outer case as shown in the figure.

Additionally, in the illustrated printing machine, the platen 13 and feed roller 1
4 are separated, but the present invention can be similarly applied to a printing machine having an integral structure in which a part of the peripheral surface of the feed roller is used as a platen. Further, the present invention can be similarly applied to a printing machine in which the printing machine main body 1 and the outer cases 2A and 2B are integrated.

〔effect〕

As is clear from the above description, according to the present invention, even when thick paper is used as printing paper, an increase in frictional load during paper feeding can be suppressed without increasing the size of the printing machine. A paper feeder force S is provided that can prevent paper from curling after printing.

[Brief explanation of drawings]

FIG. 1 is a perspective view illustrating a printing machine equipped with a paper feeding device according to an embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view of the central part showing essential parts of the printing machine shown in FIG. 1...Printing machine main body, 2A, 2B...Exterior case, 4
...Print paper, 12...Print head, 14...Feed roller, 15A, 15B...Pinch row 2.16.
...Top paper guide, 18...Paper outlet, 20...
Lower paper guide, 22...guide extension.

Claims (3)

[Claims] (1) In a paper feeding device of a printing machine, which is equipped with a feed roller for feeding printing paper and a paper guide for guiding the printing paper to the outer periphery of the feeding roller, the paper guide is placed in at least two locations, one at the top and one at the bottom of the printing machine. The curvature of the printing paper from the paper guide during paper feeding is arranged so that the lower paper guide has a smaller curvature than the upper paper guide, and a guide extension is provided on the entrance side of the lower paper guide. Characteristic paper feeding device. (2) The paper feeding device according to claim 1, wherein the guide extension portion is located at the lower part of the back of the printing machine. (3) A patent claim characterized in that the guide extension is detachably attached to the printing machine, the guide extension is provided with feet for supporting the printing machine, and the rear part of the printing machine is raised when the guide extension is attached. A paper feeding device according to scope 1 or 2.