JP2564989Y2 - Printer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly, to a printer having a paper feed mechanism.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view of a main part of a paper feed mechanism of a conventional printer, and FIG. 5 is a side view of a main part of a paper feed mechanism of a conventional printer. In the drawing, reference numeral 1 denotes a platen, 2 denotes a print medium such as paper, and 3 denotes a print head for printing on the print medium 2. The platen 1 is supported by a side frame 11 by gears 4 and 5 and a belt 6 for transmitting power of a driving means 7 such as a pulse motor so that the platen 1 can rotate in conjunction with the driving means 7. The paper chute 8 is provided so as to surround the platen 1 from the back to the front. The paper chute 8 is formed so that the printing medium 2 is smoothly fed along the platen 1, and is supported by the side frame 11 like the platen 1. The ribbon protector 9 guides the print medium 2 so as to be wound around the platen 1. The paper chute 8 is provided with windows 10 at a plurality of intervals for a plurality of pinch rollers 12 to contact the platen 1. The plurality of pinch rollers 12-a and 12-b are supported by a roller holder 15 in a structure that can be independently rotated. The pinch roller 12 is provided so as to abut the platen 1 by the spring force of a spring 16 fixed to the base frame 17, and the print medium 2 is held between the platen 1 by the spring force. The printing medium 2 can be conveyed with the rotation of the platen 1 due to the contact friction between the platen 1 and the printing medium 2 generated by the rotation.

[0003]

However, in the apparatus having the above structure, when the printing medium is thick paper or the like, the leading end of the printing medium is at the position A shown in FIG. 5, that is, the inserted printing medium 2 is moved to the pinch roller 12-a. When the print medium is not completely engaged, the print medium is not strongly pressed by the platen by the pinch roller, so that the contact friction between the print medium and the platen is small. Since the pinch roller needs to be spread out in a direction away from the platen, a force that hinders the conveyance of the print medium is generated. For this reason, there was a problem that the supply of the printing medium was not performed smoothly. Also, if the print medium is 1
Even in the state where only one of 2-a and 12-b is pressed, the contact friction between the print medium and the platen similarly becomes small, so that the print medium is not smoothly transported and a line feed is performed. There is a problem that pitch accuracy unevenness occurs.

[0004]

According to the present invention, there is provided a printer comprising: a platen connected to a driving means; a paper chute for guiding a printing medium to be wound around the platen; In a printer having a pinch roller for pinching a medium guided by the paper chute, the pinch roller is a first pinch roller, and a second pinch is arranged in parallel with the first pinch roller in a sheet conveying direction. A first pinch roller and the second pinch roller,
Power transmission means for transmitting power so that the first pinch roller and the second pinch roller rotate at a constant speed to each other; the first pinch roller, the second pinch roller, and the power transmission A support member for supporting the means in a predetermined positional relationship, and pressing the support member in a direction connecting an axis of the first pinch roller and an axis of the second pinch roller to the axis of the platen. It is characterized by comprising a pressing means.

[0005]

According to the printer of the present invention, even when the pinch roller moves in the direction away from the platen due to the thick paper biting into the pinch roller, the pressing means is arranged to increase the pressing force between the other pitch rollers and the platen. And the support member secures the positional relationship between the other pinch rollers, the power transmission means, and the pinch rollers, so that the rotation from the platen is reliably transmitted to the pinch rollers, so that the transport of the thick paper is ensured.

[0006]

1 is an exploded perspective view showing a main part of a printer according to an embodiment of the present invention, and FIG. 2 is a side view thereof.
In the drawing, 1 is a platen, 2 is a print medium such as paper, 3 is a print head for printing on the print medium 2, and 7 is a driving means such as a pulse motor. The pulse motor 7 has a gear 4,
5. The platen 1 can be rotated via the belt 6. The paper chute 8 guides the print medium along the platen 1, and has a plurality of windows 10 through which a plurality of pinch rollers 12 contact the platen 1. The ribbon protector 9 guides the print medium so as to be wound around the platen.
Side frame 11 consists of platen 1 and paper chute 8
I support.

The plurality of pinch rollers 12-a, 12
-B has an axis in the same direction as the axial direction of the platen 1, and this axis is provided with gears 13-a and 13-b, respectively.
It is rotatably supported by a roller holder 15. The roller holder 15 has an idle gear 14,
The gears 13-a and 13-b are in mesh with each other, so that when one of the pinch rollers rotates, the idle gear 14
, The other pinch roller also rotates. The rotation ratio between the pinch rollers 12-a and 12-b is set to be 1: 1. A spring 16 fixed to the base frame 17 is provided below the roller holder 15, and the plurality of pinch rollers 12 come into contact with the platen 1 by this spring force.

Next, the operation of the paper feed mechanism of the present invention will be described. In FIG. 2, when the print medium 2 is inserted and the leading end of the print medium 2 comes to the position A in the figure and abuts on the platen 1 and the pinch roller 12-a, the print medium is
While being pushed downward, 2-a is pinched by the platen 1 and the pinch roller 12-a. At this time, the pinch roller 12-a is separated from the platen,
Since 2-b is in contact with the platen 1, the pinch roller 12-b rotates with the rotation of the platen, and the gears 13-b,
The pinch roller 12-a also rotates via the idle gear 14 and the gear 13-a. As a result, the print medium is fed by the rotation of both the platen 1 and the pinch roller 12-a, so that the print medium is stably conveyed. Similarly, even after the end of the print medium 2 is disengaged from the pinch roller 12-a, the pinch roller 12-b is driven by the pinch roller 12-a.
Is sent stably. 3A and 3B show another embodiment of the present invention, in which FIG. 3A shows a pair of pinch rollers 12-a, 1--1.
2-b is coupled by a toothed belt 19. (B) is a pair of pinch rollers 12-a and 12-a.
-B is coupled by a rubber roller 20 that presses against both pinch rollers. Even when the pinch roller is coupled by such a method, the same effect as described above can be obtained, and the print medium can be stably conveyed.

In each of the above embodiments, the pinch rollers 12 are arranged in two rows in the circumferential direction of the platen, but may be arranged in three or more rows.

[0010]

As described above in detail, according to the present invention, in a mechanism in which a print medium is pressed against a platen by a pinch roller and the print medium is transported by rotation of the platen, A pair of pinch rollers arranged side by side are connected by a power transmission means, and a supporting member for securing the positional relationship between the pinch rollers and a pressing means for pressing the supporting member are used to separate the end of the printing medium from the rear pinch roller when the printing medium is inserted. Even when this occurs, the rotation corresponding to the sheet feed amount of the platen can be transmitted to the pinch roller, so that the print medium can be stably conveyed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part of a printer having a paper feed mechanism according to an embodiment of the present invention.

FIG. 2 is a side view of a main part of the printer having the paper feeding mechanism according to the embodiment of the present invention;

FIG. 3 is a perspective view of a pinch roller according to another embodiment of the present invention.

FIG. 4 is an exploded perspective view of a main part of a printer having a conventional paper feed mechanism.

FIG. 5 is a side view of a main part of a printer having a conventional paper feed mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Platen 12 Pinch roller 13 Gear 14 Idle gear 15 Roller holder

Claims (1)

(57) [Scope of request for utility model registration] 1. A platen connected to a driving means, a paper chute for guiding a printing medium to be wound around the platen, and a medium which is brought into contact with the platen in the same axial direction and is guided by the paper chute. in a printer having a pinch roller for the pinch roller and the first pinch roller, while being configured for the first peak <br/> Nchirora from the second pinch rollers that are arranged in the sheet conveying direction Coupling the first pinch roller and the second pinch roller ,
The roller and the second pinch roller rotate at a constant speed relative to each other
Power transmission means for transmitting power so that the first pinch roller and the second pinch roller
A support member for supporting the power transmission means in a predetermined positional relationship
When the second pinch roller and the axis of the first pinch roller
In the direction connecting the axis of the platen to the intermediate axis of the axis
Characterized by comprising a pressing means for pressing the support member
Printer.