JPH07195777A - Paper feed device - Google Patents

Abstract

PURPOSE:To reduce not only a roller but also a drive system and to reduce the number of parts to a large extent by providing a paper feed and discharge roller in contact with the paper placed on a paper placing stand. CONSTITUTION:A paper feed and discharge roller 4' is rotated in the direction shown by an arrow (a) and a retard roller 5 is allowed to follow the roller 4' and a slide clutch 22b races. Next, a push-up lever 3 is revolved in the direction shown by an arrow (b) to push up the paper in a paper feed cassette 2. The slide clutch 22 begins to slide upon the reception of definite load and the paper is continuously pressed upwardly under the definite load by the push-up lever 3. By this constitution, the leading end of the paper is appropriately pressed to the surface of the paper feed and discharge roller 4' and the paper is taken out to the outside of the paper feed cassette 2 by the rotation of the paper feed and discharge roller 4' to be fed in the direction of a printing part. When printing due to a final color is completed, the paper feed and discharge roller 4' is reversed in the direction shown by an arrow (c) and printed paper is discharged to the outside of a main body apparatus from a paper discharge port by the paper feed and discharge roller 4' and a paper discharge roller 11'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device having a reliable paper feeding / discharging function with a simple and inexpensive mechanism provided inside a printer or the like.

[0002]

2. Description of the Related Art In a conventional thermal printer, for example, as shown in FIG. 4, when feeding paper, a paper feed cassette 2 in a main body 1 is pushed upward by a push-up lever 3 as shown by an arrow D in the figure. Then, the leading end of the paper P stored in the paper feed cassette 2 is brought into contact with the paper feed roller 4, and the paper feed roller 4 is rotated in the clockwise direction indicated by the arrow C in the figure. And
The retard roller 5 functions to prevent double feed of paper (double feed) while the uppermost paper P in the paper feed cassette 2 is directed toward the printing unit 6 arranged on the left side of the apparatus. The paper was feeding to the left as indicated by the arrow. Paper P
Is fed to the printing unit 6 while being guided by the paper feed guide plate 7 and the paper feed / discharge guide plate 8. Further, when printing is completed and the printed paper is discharged, the paper feed / discharge guide plate 8 and the discharge guide plate 9
The printed sheet P ′ guided and delivered by the sheet is sandwiched between the sheet discharge roller 10 and the sheet discharge roller 11, and the sheet discharge roller 10 is rotated to print the sheet P ′ printed from the sheet discharge port 12.
Was discharged to the outside.

[0003]

By the way, such a small electronic device, which is used for personal use, is required to be further small and inexpensive as much as possible. Therefore, it must be produced at the lowest possible cost. Therefore, if the number of parts is reduced by one, not only the reduced unit price of the parts,
Assembling man-hours can be reduced, which will contribute greatly to product cost reduction. Not only that, but also because the number of parts is reduced, the failure rate will be reduced and the reliability of the product will be improved.

However, the above-mentioned thermal printer is sufficiently miniaturized, and it goes without saying that the printed portion is
Both the paper feeding system and the paper discharging system are indispensable parts for the printer, and it can be said that there are no more parts to be reduced, and there is a problem that further downsizing and cost reduction are difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet transporting device which surely functions with a simple and inexpensive mechanism composed of a smaller number of parts.

[0006]

The structure of the sheet conveying apparatus according to the present invention will be described below. A sheet conveying device of the present invention includes a sheet feeding / discharging roller that contacts a sheet placed on a sheet mounting table, a sheet discharging assisting unit that contacts the sheet feeding / discharging roller, and the sheet feeding / discharging roller in both forward and backward directions. And driving means for rotating the mounting table in a direction separating from the paper feeding / discharging roller. The paper is conveyed from the inside of the device to the paper feeding and discharging roller by rotating the paper feeding and discharging roller in the opposite direction by the driving means. It is configured to be discharged to the outside of the apparatus by the paper assisting means.

[0007]

According to the present invention, the sheet feeding / discharging roller which is rotationally driven by the driving means rotates in the forward direction to convey the sheet on the mounting table into the apparatus, and the sheet feeding / discharging roller also rotates in the reverse direction. Then, the sheet inside the apparatus is discharged to the outside of the apparatus with the help of the sheet discharge assisting means. In the case of automatic paper feeding, the moving means moves the mounting table in a direction away from the paper feeding / ejection roller every time one paper is fed.

As a result, the number of rollers dedicated to paper discharge is reduced,
It is possible to realize a paper transporting device that surely functions with a simple and inexpensive mechanism including a smaller number of parts.

[0009]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a side sectional view schematically showing the configuration of a thermal printer according to an embodiment. In the figure, the same components as those of the thermal printer shown in FIG. 4 are designated by the same reference numerals.

In this embodiment, the sheet feeding / discharging guide plate 8 and the sheet discharging roller 10 are removed from the construction of the thermal printer shown in FIG. By removing the paper discharge roller 10, the drive system such as a drive motor that has driven the paper discharge roller 10 is also removed, although not particularly shown. Further, in this embodiment, the paper feed guide plate 7 and the paper discharge guide plate 9 shown in FIG. 4 are arranged such that the arrangement positions thereof are slightly inclined with respect to each other, that is, they are closer to each other, and they also have respective functions. It is provided as new paper feed / discharge guide plates 7'and 9 '. In particular, the paper feed roller 4 shown in FIG. 4 is provided with a new function as a paper feed / ejection roller 4'which serves both as paper feed and paper ejection in this embodiment. It is configured to be rotatable both in the direction of rotation and in the counterclockwise direction. Further, in this embodiment, the paper discharge roller 11 shown in FIG. 4 is changed in arrangement so as to come into contact with and follow the paper supply / discharge roller 4 ', and this also has a new function as the paper discharge roller 11'. ing. The main body device 1'of this embodiment is
The paper feed / discharge guide plate 8, the paper discharge roller 10, and the paper discharge roller 1
By removing the 0 drive system, it is formed to be more compact and lower in height than the configuration shown in FIG.

In the configuration of the embodiment shown in FIG. 1, the printing section 6 arranged on the left side of the apparatus has a structure as shown in FIG.
A sheet conveyance roller 13 and a driven roller 14 which is pressed against the sheet conveyance roller 13 by a spring or the like and is driven during printing are disposed. The driven roller 14 is configured so that it can be removed from the pressure contact with the sheet conveying roller 13 during non-printing. The sheet conveying roller 13 holds the sheet by the driven roller 14, rotates in the counterclockwise direction indicated by the arrow W in the figure to carry in the sheet P, and rotates in the clockwise direction indicated by the arrow in the figure. The printed paper P'is discharged. Further to the left of the paper transport roller 13 and the driven roller 14,
A platen roll 15 is arranged which is driven to rotate counterclockwise by a drive device (not shown). Below that, the thermal head 16 for printing on the paper P is
The platen roll 15 is opposed to the platen roll 15 and is movably arranged in both up and down directions indicated by arrows a and b in the figure. The thermal head 16 is a print head having a width substantially the same as the width of the paper P, and includes the same number of print elements (heating elements) as the maximum number of print dots in the main scanning direction (paper width direction). The thermal head 16 moves upward during printing, and presses the ink ribbon 17 and the paper P, which are indicated by the two-dot chain line in the figure, against the platen roll 15. The ink ribbon 17 is a long ink ribbon having a width substantially the same as the width of the paper P, and at the time of printing, it is sent out from the supply core 18 in the counterclockwise direction indicated by the arrow E in the figure. This ink ribbon 17 is used for the thermal head 1.
While the heat energy corresponding to the print data is transferred by the heating element 6 to transfer the ink on the ribbon onto the paper P (to the lower surface of the paper in the figure), the counterclockwise arrow of the winding core 19 shown by arrow C in the figure. The winding core 19 is wound by the rotation in the rotating direction. Normally, multicolor printing is performed by subtractive color mixture Y (yellow: yellow), M (magenta: red dye),
And three primary colors of C (cyan: greenish blue) are mixed in various proportions to express various shades (actually, black is further added and expressed in four colors, but omitted in the following description). . Therefore, the above three primary colors Y, M, and C are sequentially arranged in the transport direction on the multicolor printing ink ribbon in a size corresponding to the area of one sheet of paper.

The printing portion guide plate 20 disposed on the left side of the upper portion of the printing portion 6 is formed so as to be curved in a convex shape upward, and has a slightly waist like a business card carried into the printing portion. The hard paper P is appropriately received from above and pressed to be supported.

A plurality of sheets of paper P (image receiving paper) are placed in the paper feed cassette 2 in an overlapping manner during automatic paper feeding. The push-up lever 3 is rotationally driven by a slip clutch, which will be described later, on its support shaft, and is rotated in the upward direction indicated by arrow D in the figure to push up the bottom plate of the bottom of the paper feed cassette 2 to raise the uppermost sheet P. The leading end of the sheet is brought into contact with the sheet feeding / discharging roller 4 '. Then, at the timing when the feeding of one sheet of paper is completed, the entire sheet P is separated from the sheet feeding / discharging roller 4'by rotating downward in the direction indicated by arrow E in the figure.

The retard roller 5 which is urged to come into pressure contact with the paper feeding / discharging roller 4'is driven via a slip clutch to be described later so as to rotate in a clockwise direction shown by an arrow mark in the figure. However, in a normal state, the retard roller 5 resists the driving force due to the frictional force with the sheet feeding / discharging roller 4 ′ that overcomes the driving force of the slip clutch or the frictional force with the sheet of paper P to be fed. Is driven by the rotation of the paper feeding / discharging roller 4'and rotates in the counterclockwise direction indicated by the arrow in the figure. When the paper P is double-fed by the paper feed / ejection roller 4 ', the driving force of the slip clutch is more double-fed.
Overcoming the frictional force acting between them, the retard roller 5 rotates in the clockwise direction indicated by the arrow N in the figure according to the driving force,
The lower multi-fed paper P is pushed back into the paper feed cassette 2. As a result, one sheet P is always fed.

Although not shown in the figure, a controller for controlling the drive system and the printing unit is arranged in the main body 1 '. FIG. 2 shows a usage state of the slip clutch. This figure shows the paper feed cassette 2, the push-up lever 3, the paper feed / discharge roller 4 ', the retard roller 5 and the two paper discharge rollers 11' shown in FIG. 1, the push-up lever 3 and the retard roller 5 respectively. The slip clutches 22a and 22b which transmit rotational driving force are shown. The slip clutches 22a and 22b shown in FIG. 2 are slightly loosely fitted to the drive side and the non-drive side, each of which has a large number of concave and convex portions, in the viscous oil contained in the clutch, and are transmitted from a drive source (not shown). The generated driving force is transmitted to the push-up lever 3 and the retard roller 5 by viscous resistance of the viscous oil agent. When the load of the retard roller 5 (or the push-up lever 3) on the non-driving side exceeds a certain limit, the slip clutch 22b (or the slip clutch 22a) is configured to start idling. The arrows and reference numerals shown in FIG. 2 are the same as the arrows and reference numerals shown in FIG.

Next, referring to FIG. 3 (a) and FIG. 3 (b), the operation state diagram of the sheet feeding / discharging roller 4'and FIG. This will be described below.

First, when the paper feeding / discharging roller 4'starts rotating in the clockwise direction shown by the arrow H in the figure, the retard roller 5 is driven by this and the slip clutch 22b idles. Next, the push-up lever 3 starts to rotate in the upward direction indicated by the arrow D in the figure to push up the paper P in the paper feed cassette 2. The slip clutch 22a starts slipping when a constant load is applied, and under the constant load, the push-up lever 3 continues to press the paper P upward. As a result, the leading edge of the paper P is appropriately pressed against the surface of the paper feed / discharge roller 4 ', and the paper P is taken out of the paper feed cassette 2 by the rotation of the paper feed / discharge roller 4'. It is conveyed in the direction of the printing unit 6 shown. At this time, even if the plurality of sheets P are taken out from the sheet feeding cassette 2, only the uppermost one sheet is conveyed by the action of the retard roller 5 described above.

When the paper P starts to be conveyed, the rotation direction of the drive system for driving the push-up lever 3 is reversed. As a result, the push-up lever 3 is rotated downward as shown by arrow E in the figure. By this rotation, the paper P in the paper feed cassette 2
Is separated from the surface of the paper supply / discharge roll 4 '. As a result, the feeding of the sheet from the sheet feeding cassette 2 is stopped until the next sheet feeding timing. The push-up lever 3 is pressed against the lower part of the case of the main body device 1 ', and the slip clutch 22a starts idling to stop at the lower position of the case.

The leading edge of the sheet P conveyed to the printing section 6 reaches the sheet conveying roller 13 before long. The driven roller 14 descends from the position where the driven roller 14 is located until then, and comes into pressure contact with the sheet conveying roller 13 so as to contact the sheet conveying roller 13 and the sheet P.
To pinch. The paper transport roller 13 rotates in the counterclockwise direction indicated by the arrow w in the figure to carry the paper P into the printing unit 6,
The rear end of the carried-in paper P is gripped together with the driven roller 14 and stopped.

The thermal head 16 moves from the lower position, which has been positioned up to that point, to the upper position shown by the arrow A in the figure, and presses the ink ribbon 17 and the paper P against the platen roller 15.
The control controller (not shown) heats the heating elements of the thermal head 16 corresponding to the print information,
The sheet conveying roller 13 is rotated in the clockwise direction indicated by arrow W in the figure, and the winding core 19 is rotated in the counterclockwise direction indicated by arrow C in the figure.

By winding the winding core 19, the ink ribbon 17 is pulled out from the supply core 18, and the unused ink portion is continuously supplied to the thermal head 16. On the other hand, the paper P is discharged in the direction of the paper feeding / discharging roller 4'while being sequentially printed from the rear end of the lower surface, and its rear end reaches the upper surface of the paper feeding / discharging roller 4'and the paper feeding / discharging roller 4'and the paper discharging. Roll 1
It is sandwiched between 1 '.

At the same time as the printing is started, the paper feeding / discharging roller 4'restarting to rotate in the clockwise direction indicated by the arrow in the drawing is the paper discharge port indicated by the arrow in the drawing at the rear end of the printed paper P '. 12 Carry it out (see Fig. 3 (a)).

When the printing of the first color is completed, the paper transport roller 13 stops while holding the leading edge of the paper P, and the thermal head 16 descends downward as indicated by the arrow B in the figure, while
The winding of the ink ribbon 17 by the winding core 19 is stopped.

Subsequently, the paper transport roller 13 is rotated in the counterclockwise direction indicated by the arrow w in the figure, and the paper feed / discharge roller 4'is provided.
Is rotated counterclockwise as indicated by the arrow in the figure. As a result, the paper P is conveyed again in the direction of the printing unit 6 indicated by the arrow (see FIG. 3B), and is carried into the printing unit 6 by the paper carrying roller 13.

The printing of the second color is performed in the same manner as the printing of the first color described above. In this way, the first color Y
Alternatively, every time printing with the second color M is completed, the paper P is carried to the printing start position in the printing unit 6 in order to print the next color, the second color M or the third color C, in an overlapping manner. Is
When the printing with the last color C is completed, the sheet is discharged from the sheet discharge port 12 to the outside of the main body apparatus 1'by the sheet supply / discharge roller 4 '.

In the present embodiment, the case of a thermal printer has been described as an example, but the paper conveying apparatus of the present invention is not limited to a thermal printer, and any paper feeding and discharging apparatus can be used. It can also be applied to devices. Further, the shape is not limited to the shape shown in the present embodiment, and for example, the discharge roller 11 'may be changed to a plate shape.
Further, the shape of the paper feeding portion need not be limited to this embodiment. For example, instead of using a paper cassette, a paper placing table dedicated to manual paper feeding may be used. In this case, the retard roller 5 and the push-up lever 3 may be constantly pressed against the paper feeding / discharging roller 4 ', and the rotation mechanism may be used. It becomes unnecessary. Also, when using a paper having a soft waist, the retard roller is almost unnecessary. In the case of automatically feeding such soft paper, it is sufficient to provide double feed preventing claws at both ends of the leading end of the paper feeding cassette 2. Also, the slip clutch 22
Although viscous oil is used for a and 22b, for example, a spring slip clutch may be used, and any kind of slip clutch may be used.

[0027]

As described above in detail, according to the present invention, the use of the two rollers of the paper feed roller and the paper discharge roller is stopped, and the paper feed and the paper discharge are performed by the one paper feed and discharge roller. As a result, not only the rollers but also the drive system can be reduced, so that the number of parts is greatly reduced and the product cost is reduced. Further, since the number of parts is small, the apparatus main body can be downsized.
Further, since the number of parts is small, the product failure is reduced and the product reliability is improved.

[Brief description of drawings]

FIG. 1 is a side sectional view schematically showing a configuration of a thermal printer according to an embodiment.

FIG. 2 is a diagram illustrating a usage state of a slip clutch.

3 (a) and 3 (b) are diagrams for explaining an operating state of a paper supply / discharge roller.

FIG. 4 is a diagram showing a sheet conveying device of a conventional thermal printer.

[Explanation of symbols]

 1'Main unit 2 Paper feed cassette 3 Push-up lever 4'Paper feeding and discharging roller 5 Retard roller 6 Printing section 7 ', 9'Paper feeding and discharging guide plate 11' Paper discharging roller 12 Paper discharging port 13 Paper conveying roller 14 Followed roller 15 Platen roller 16 Thermal head 17 Ink ribbon 18 Supply core 19 Winding core 20 Printing part guide plate P Paper P'Printed paper 1 Main unit (conventional) 4 Paper feed roller (conventional) 7 Paper feed guide (conventional) 8 Supply Paper ejection guide plate (conventional) 9 Paper ejection guide plate (conventional) 10 Paper ejection roller (conventional) 11 Paper ejection roller (conventional)

Claims (2)

[Claims] 1. A paper feeding / discharging roller that abuts a sheet placed on a sheet mounting table, a sheet ejection assisting unit that abuts the sheet feeding / discharging roller, and the sheet feeding / discharging roller is rotationally driven in both forward and reverse directions. Driving means for rotating the paper feeding / discharging roller in the forward direction by the driving means to convey the paper on the mounting table into the apparatus, and the driving means for moving the paper feeding / discharging roller in the reverse direction. The sheet conveying apparatus, wherein the sheet conveyed from the inside of the apparatus by being rotated to the outside is discharged to the outside of the apparatus by the sheet feeding / discharging roller and the sheet discharge assisting means. 2. The sheet conveying apparatus according to claim 1, further comprising a moving unit that moves the mounting table in a direction in which it separates from the sheet feeding / discharging roller.