JPH06246992A - Printer - Google Patents

Abstract

PURPOSE:To reduce the blank part of paper and to make paper jamming hard to generate in a printer performing printing by bringing a thermal head into contact with a platen roller under pressure. CONSTITUTION:The feed leading end part of fed paper 14 is held by a clamper 2. The clamper 2 is rotated centering around the center axis of a platen roller 1 in the rotary direction of the platen roller 1 in synchronous relation to the rotation of the roller. A thermal head 4 is brought into contact with the platen roller 1 under pressure through the paper 14 held by the clamper 2. This pressure contact is released corresponding to the rotary position of the clamper 2. Since the paper 14 is rotated while held by the clamper 2, even when a printing position is separated from the position of a pinch roller 3a or 3b, the blank part of the paper can be reduced and paper jamming can be made hard to generate.

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 for printing by pressing a thermal head against a platen roller.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG. FIG. 8 is a perspective view showing a paper feeding mechanism portion and a printing portion of a conventional printer. This figure shows a color printer that performs overpainting with three or four colors.

During standby, the thermal head 4 and the platen roller 1 are separated from each other. An ink ribbon 10 passes between the thermal head 4 and the platen roller 1, and a constant tension is applied. A capstan roller 11 and a pinch roller 12 are provided above the thermal head 4, and the capstan roller 11 is connected to the paper feed motor 104 via a speed reduction mechanism 13.

When the printing operation is started, the paper 14 indicated by the broken line is sent to the printing section through between the thermal head 4 and the platen roller 1, and the leading end of the paper 14 is capstan roller 11 and fixed pinch roller. It is strongly sandwiched between 12. After that, the thermal head 4 is pressed against the platen roller 1, and the capstan roller 11 moves to the paper feed motor 1.
By 04, it rotates at a constant speed and printing (printing) is started.

The ink ribbon 10 is fed from the supply side 10a to the take-up side 10b at a constant speed with the paper 14 while maintaining tension. The dye is transferred from the ink ribbon 10 to the paper 14 by the heat given by the thermal head 4. The platen roller 1 is pulled by the paper 14 and rotates at the same speed as the paper 14.

When the printing is completed up to the rear end of the sheet 14, the thermal head 4 separates from the platen roller 1. Next, the paper feed motor 104 is rotated in the reverse direction, the leading edge of the paper 14 is returned to a position between the capstan roller 11 and the fixed pinch roller 12, and printing for the second and subsequent colors is performed.

When the printing of three or four colors is completed, the paper 1
4 is discharged from the printing section.

[0008]

In the above-mentioned conventional printer, the positions of the capstan roller and the fixed pinch roller for holding the paper and the position for printing with the thermal head and the platen roller are separated from each other. There is a drawback that the blank area on the paper is large.

Further, in the conventional printer, the paper is returned as indicated by the arrow Y for the purpose of multicolor printing, so that the point where static electricity is generated due to the friction between the ink ribbon and the paper and the rear end portion of the paper conveyed. There is a drawback that a paper jam is likely to occur at the time of returning the paper because of two reasons that it is free.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to provide a printer in which a margin portion on a sheet is reduced and a sheet jam is less likely to occur.

[0011]

A printer according to the present invention is a printer for performing printing by pressing a thermal head against a platen roller, and a clamper for holding a conveying leading end portion of a conveyed sheet, and the platen roller. Rotation drive means for rotating the clamper in the rotation direction of the roller about the rotation center axis of the roller in synchronism with the rotation of the roller, and the thermal head is pressed against the platen roller via the paper held by the clamper. And a pressure contact releasing means for releasing the pressure contact by the pressure contact means according to the rotational position of the clamper.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the construction of a printing section of an embodiment of a printer according to the present invention, and the same portions as those in FIG. 8 are designated by the same reference numerals. In the figure, in the printer of the present embodiment, a clamper 2 is provided in the printing portion, and the clamper 2 holds the leading end portion of the sheet 14 conveyed. Then, in this held state, the clamper 2 is moved in the direction of the arrow Y around the rotation center axis of the platen roller 1.
It is rotated in the direction of 2.

Further, in this printing section, motors 102 to 104 for driving the respective sections are provided. The thermal head drive motor 104 drives the thermal head 4 so as to press the platen roller 1 into or out of contact with it, as indicated by an arrow Y4.

The platen roller drive motor 101 rotates the platen roller 1 in the direction of arrow Y3 at an arbitrary speed.

The clamper drive motor 102 rotates the clamper 2 around the platen roller 1 while holding the leading end of the sheet 14 by the clamper 2. At this time, the clamper drive motor 102 and the clamper 2 are connected through the clutch 6 to match the speed so that the rotation speed of the platen roller 1 and the conveyance speed of the paper 14 pulled by the clamper 2 match. Moreover, the paper 14 is given a constant tension.

The rotational position of the clamper 2 is read by the clamper position detection sensor 7, the movement of the clamper drive motor 102 and the pinch roller movement motors 103a and 103b.
A signal is sent to regulate the movement of the. Then, depending on the rotational position of the clamper 2, the pressure contact of the thermal head 4 with the platen roller 1 and the pressure contact of the pinch rollers 3a, 3b are released.

The pinch roller moving motor 103a drives the pinch roller arm 5a to control the feed side pinch roller 3a to come into pressure contact with or separate from the platen roller 1 as shown by an arrow Y5. Further, the pinch roller movement motor 103b uses the pinch roller alarm 5b.
Is driven to control the pull-side pinch roller 3b to come into pressure contact with or separate from the platen roller 1 as indicated by an arrow Y6.

The clutch 6 is rotated by stopping the rotation axis common to the rotation axis of the platen roller 1, canceling out the difference between the rotation speed of the platen roller 1 and the rotation speed of the clamper 2, and rotating both in synchronization. It is provided for.

In this example, three clampers 2 are provided and fixed by a shaft 20 at a position separated from the rotation axis of the platen roller 1 by a predetermined distance.

The operation of the printer of this embodiment having the above configuration will be described with reference to the drawings. 2 to 7 are schematic views showing the operations of the paper 14, the clamper 2, the thermal head 4, and the pinch rollers 3a and 3b in the printer of this embodiment, and the same portions as those in FIG. 1 are designated by the same reference numerals. It is assumed that the state of each part changes in the order of FIGS.

First, FIG. 2 shows a state in which the leading end of the sheet 14 fed as indicated by arrow Y1 is held by the holding operation of the clamper 2 in the direction of arrow Y6. In addition,
At this time, the pinch rollers 3a and 3b and the thermal head 4 are separated from the platen roller 1.

FIG. 3 shows that the clamper 2 holding the paper 14 rotates around the platen roller 1 in the direction of the arrow Y2 and the paper 14 is pulled between the thermal head 4 and the platen roller 1. There is. At this time, the feed side pinch roller 3a is brought into pressure contact with the platen roller 1 to apply tension to the portion of the paper 14 sandwiched between the clamper 2 and the pinch roller 3a.

FIG. 4 shows how the thermal head 4 presses against the platen roller 1 to start printing. At this time, the platen roller 1 rotates in the direction of arrow Y3 at a constant speed. The paper 14 is pulled by the clamper 2, but is rotated together with the platen roller 1 in the direction of arrow Y3 due to the friction with the rubber of the platen roller 1. Therefore, the clamper 2 always applies a constant tension to the paper 14.

FIG. 5 shows that the clamper 2 has moved to the position shown and the pinch roller 3b on the pulling side is in pressure contact with the platen 1. Since the tension is applied to the paper 14 by pulling the clamper 2, the paper 14 in the section sandwiched between the two pinch rollers 3a and 3b is provided.
Presses against the platen roller 1.

FIG. 6 shows that when the clamper 2 moves to the illustrated position, the feed side pinch roller 3a separates from the platen roller 1 and the clamper 2 also stops. On the other hand, the platen roller 1 continues to rotate in the direction of the arrow Y3 and prints on the end portion of the paper 14.

FIG. 7 shows a state in which printing of one color is completed, and the thermal head 4 and the pulling side pinch roller 3b are also separated from the platen roller 1.

When printing the second and subsequent colors, the process returns to the state of FIG. 3 and this process is repeated for the number of times of overlapping.
During this time, the clamper 2 continues to hold the leading edge of the sheet 14.
When printing is completed, the clamper 2 is released and the paper 14 is ejected.

As described above, in the present embodiment, since the paper is drawn around while being held by the clamper, even if the position for printing and the position of the pinch roller are separated, the printing is performed from the leading end of the paper to the terminal. This can be done and the blank area of the paper can be reduced. In addition, multicolor printing can be performed without pulling back the paper, and paper jams are reduced.

Further, since the clamper is rotated about the central axis of rotation of the platen roller, the housing of the device can be made smaller.

[0031]

As described above, according to the present invention, the margin of the paper is reduced by performing the printing while rotating around the platen roller while the front end of the conveyed paper is held by the clamper. In addition to this, there is an effect that the paper jam can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a printing unit of a printer according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the operation of the printing unit in FIG.

FIG. 3 is a schematic diagram showing an operation of the printing unit in FIG.

FIG. 4 is a schematic diagram showing an operation of the printing unit in FIG.

5 is a schematic diagram showing the operation of the printing unit in FIG.

FIG. 6 is a schematic diagram showing an operation of the printing unit in FIG.

FIG. 7 is a schematic view showing the operation of the printing unit in FIG.

FIG. 8 is a perspective view showing a configuration of a printing unit of a conventional printer.

[Explanation of symbols]

 1 Platen Roller 2 Clamper 3a Feeding Pinch Roller 3b Tensioning Pinch Roller 4 Thermal Head 5a Feeding Pinch Roller Alarm 5b Tensioning Pinch Roller Alarm 6 Clutch 7 Clamper Position Detection Sensor 10 Ink Ribbon 14 Paper 20 Shaft

Claims (2)

[Claims] 1. A printer for performing printing by pressing a thermal head against a platen roller, the clamper holding a conveyance leading end portion of a conveyed sheet, and the clamper in a rotation direction of the platen roller. Rotation driving means for rotating the roller about the rotation center axis in synchronism with the rotation of the roller, pressing means for pressing the thermal head against the platen roller via the paper held by the clamper, and the rotational position of the clamper. And a pressure contact releasing means for releasing the pressure contact by the pressure contacting means. 2. The rotation driving means fixes a clutch that rotates around a rotation axis common to the rotation axis of the platen roller, and fixes the clamper at a position parallel to the rotation axis and separated from the rotation axis by a predetermined distance. The printer according to claim 1, further comprising: