JPH03224770A - Thermal printer - Google Patents

Abstract

PURPOSE:To prevent color shift by bringing a paper guide allowing a clamper to clamp, a member to be transferred after the feed of paper into contact with the member to be transferred during a period when the member to be transferred is moved to a printing start position in a clamped state while brought into contact with the outer periphery of a platen roller to apply tension thereto. CONSTITUTION:A timing belt 3 begins to run in the direction shown by an arrow A and the clamper 9 provided on a bar 9a also begins to run in the same way. At this time, a paper guide 10 is revolved by a paper guide revolving mechanism to press recording paper 6 between the guide 10 and a roller 16 to apply load to the recording paper 6. A thermal head 8 is present at the position moved in the direction shown by an arrow E to be separated from a platen roller 1 and the clamper 9 passes through the gap between the thermal head 8 and the roller 1. When the clamper 9 reaches a printing start position, the recording paper 6 is closely brought into contact with the platen 1 by the load due to the paper guide 10 and the roller 16 and the thermal head 8 is moved in the direction opposite to the arrow E to come into contact with the platen roller 1 so as to hold the recording paper 6 and printing is started with the rotation of the platen roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording paper feeding device for a thermal printer.

[Conventional technology]

FIG. 5 shows a side view of the paper feeding mechanism of a conventional thermal printer.One recording paper 6 is fed one by one from the paper feeding mechanism opening, and the leading edge of the recording paper is inserted into the clamper 9 along the paper guide, and the clamper The clamper is closed by the opening/closing mechanism H, and the recording paper is gripped by the clamper 9.

The clamper 9 is attached to a bar 9a extending parallel to the platen roller 1 and between the timing belts 3,3.

As the timing belt 3 rotates, the clamper 9 moves in the direction of the arrow, and the thermal head 8 and platen roller 1
After passing through the gap and reaching the printing start position t, the recording paper 6 is brought into pressure contact with the thermal head 8 and the platen roller l, and the color of the ink sheet 7 that supplies the printing colorant is transferred. Particularly in the case of color printing, such transfer is repeated 8 to 4 times by changing the color of the ink sheet 7. In other words, the recording paper 6 is rotated on each pulley 2.4.5 repeatedly 8 to 4 times. become. After the above transfer is completed, as shown in FIG.
The timing belt 3 is moved in accordance with the rotation of the timing belt 3 in the input direction as described above until the point a is near the center of the recording paper discharge path 14. Next, the timing belt 3 reversely rotates in direction B, which is opposite to the input direction, and accordingly, the terminal end 6a of the recording paper 6 is guided to the recording paper ejection path 14, and
The recording paper is sandwiched between the pair of recording paper discharge rollers 15 (151) in 4 and is discharged. This state is shown in FIG. At this time, when the clamper 9 reaches the point of the clamper opening/closing mechanism H, the rotation of the timing belt 3 is stopped,
Release clamper 9. Therefore, only the recording paper 6 is discharged according to the rotation of the pair of recording paper discharge rollers 15a and 15b, and the series of color printing steps is completed.

[Problem to be solved by the invention]

Conventional thermal printers simply feed the recording paper and move it to the printing start position as described above.
There was a problem in that the recording paper could not be tightly wrapped around the platen roller, resulting in color shift in color printing. This invention was made to solve the above problems. The two objectives are to obtain a highly accurate thermal printer.

[Means to solve the problem]

The thermal printer according to the present invention includes: a platen roller for bringing the transfer member and the transfer material into close contact; a timing belt that runs in forward and reverse directions at a speed substantially equal to the circumferential speed of the platen roller; and a timing belt provided on the timing belt. , a clamper that clamps the end of a sheet-shaped transfer material, a timing belt pulley that is clamped by this clamper and causes the transfer material to run while being in contact with the outer periphery of the platen roller, and a platen roller of the transfer material when performing thermal transfer. The printer is equipped with a thermal head that contacts a portion that contacts the image forming apparatus, and a means for applying tension to the transfer member when the transfer member is conveyed to the printing start position fat.

[Effect]

In the thermal printer according to the present invention, after paper is fed, the paper guide for clamping the transfer member to the clamper is brought into contact with the transfer member while the transfer member is clamped and moves to the printing start position while contacting the outer periphery of the platen roller. By applying tension to the transfer member, the transfer start position can be fixed at a predetermined position, and color shift can be prevented.

〔Example〕

An embodiment of the present invention will be explained below with reference to the drawings. Figs. 1 to 4 show a side view and a plan view of the main parts of the paper feed mechanism in an embodiment of the invention. In Figs. Each timing belt 3 has 8 pulleys 2.4
and 5, and the left and right ones are driven at a constant speed in the direction shown by arrow A. A clamper 9 is provided on a bar 9a fixed to each timing belt 3 at both ends thereof at right angles to the running direction of the two timing belts 3. The platen roller l is supported coaxially with the pulley 2, and its circumferential speed is made substantially equal to the running speed of the timing belt 3. The thermal head 8 is connected to the platen roller 1 by a mechanism (not shown).
The platen roller 1 is brought into contact with the platen roller l only when transferring onto the recording paper 6 as a transfer target member. An ink sheet 7 serving as a transfer member is supplied from a supply roller 7a, passes between the platen roller 1 and the thermal head 8, and is wound up by a winding roller 7b.

More specifically, in FIGS. 1 to 4, the recording paper 6 is fed one by one from the paper supply mechanism 13, and its leading edge is inserted into the clamper 9 along the paper guide IO by the paper feed mechanism. Next, the clamp 9 is closed by the clamper opening/closing mechanism H, and the recording paper 6 is gripped by the clamper 9. Next, the timing belt 3 starts running in the direction shown by the arrow M, and along with this, the clamper 9 provided on the bar 9a similarly starts running. At this time, the paper guide lO is rotated by a paper guide rotation mechanism (not shown), and presses the recording paper 6 against the roller 16, thereby applying a load to the recording paper 6. The thermal head 8 is at a position moved in the direction shown by arrow E and separated from the platen roller 1, and the clamper 9 passes through the gap. When the clamper 9 reaches the printing start position, the recording paper 6 is moved between the paper guide lO and the roller 16.
The thermal head 8 moves in the opposite direction of the arrow E, comes into contact with the platen roller l across the recording paper 6, and as the platen roller l rotates, printing begins. . In other words, the ink is thermally transferred from the ink sheet 7 that is in close contact with the recording paper 6.
The recording paper 6 is transferred onto the recording paper 6 by the gutter 8.
is transported in the direction of arrow M. By the time the clamper 9 reaches the vicinity of the clamper opening/closing mechanism 11 via the second pulley 4 and the eighth pulley 5, the first transfer onto the recording paper 6 has been completed, and the thermal head 8 is moving as shown by the arrow. It moves in the direction shown by E and separates from the platen roller l.

The timing belt 3 further travels in the direction shown by the arrow M, and the clamper 9 again passes through the gap between the thermal head 8 and the platen roller 1 and returns to the printing start position. Therefore, the recording paper 6 clamped by the clamper 9 also returns to the printing start position. During this time, the ink sheet 7 is centamped to the next color. This operation is repeated 2 to 8 times to complete color printing. [Effects of the Invention] As described above, according to the present invention, a load can be applied to the printing start position after paper feeding before the recording paper is set up. This causes the recording paper to wrap tightly around the platen roller.
It becomes possible to provide a printer with good printing quality and less color shift. It is also possible to attach a high friction material such as rubber to the roller surface to increase the load.

[Brief explanation of drawings]

1 to 8 are side views showing the respective operating modes of an embodiment of the present invention, FIG. 4 is a plan view in a printing state, and FIGS. 5 to 7 are respective views of a conventional thermal printer. FIG. 3 is a side view showing an operation mode. In the figure, 1 is a platen roller, 2.4.5 is a pulley 3 is a timing belt, 6 is a recording paper (transferring member), 7 is an ink sheet, 8 is a thermal head, g is a clamper,
10 is a paper conveyance guide, ■ is a clamper opening/closing mechanism, 13
14 is a paper supply mechanism, 14 is a discharge path, and 16 is a roller.

Claims (1)

[Claims] A platen roller for bringing the transfer material into close contact with the transfer material; a timing belt that runs in a fixed direction at a speed substantially equal to the circumferential speed of the platen roller; A clamper that clamps, a timing belt pulley that causes the transferred member clamped by the clamper to run while contacting the outer periphery of the platen roller, a thermal head that contacts the portion of the transferred member that contacts the platen roller when performing thermal transfer,
and a thermal printer comprising means for applying tension to the transfer target member when conveying the transfer target member to a printing start position.