JPH0532358A - Sheet inclination correction device for thermal transfer color printer - Google Patents

Abstract

PURPOSE:To prevent the rubber roll section of a platen roller from being scraped by a correction lever for correcting sheet inclination. CONSTITUTION:A disc-shaped positioning plate 7c is fitted at both sides of the rubber roll section 7b of a platen roller 7. The plate 7c is so sized as to have a smaller diameter than the rubber roll section 7b. The ends 8a of correction levers 8 as a pair to correct the inclination of a sheet 50 are pressed against a positioning plate 7c with a slight gap G from the rubber roll section 7b, thereby preventing the progress of the sheet 50. According to this construction, the ends 8a do not come in contact with the rubber roll section 7b and, therefore, the scraping of the section 7b can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper skew correction device for correcting the skew of paper supplied to a thermal transfer color printer such as a video printer or a card printer.

[0002]

2. Description of the Related Art FIGS. 5 to 7 show a conventional example of a sheet inclination correcting device used in a thermal transfer color printer. Paper 50
Is guided by the guides 51 and 52, and the platen roller 53
To the platen roller 53 by the pressure roller 54.
Is pressed by. The platen roller 53 has a rubber roll section, and the sheet 50 is conveyed by friction with the rubber roll section when the sheet 50 is pressed against the rubber roll section. When the sheet 50 is conveyed by the platen roller 53, the front end of the sheet 50 contacts a pair of straightening levers 56 provided near both ends of the platen roller 53 and contacting the rubber roll portion of the platen roller 53 by the spring 55. Contact.

By the way, the paper 50 is often conveyed with its front end inclined with respect to the axis of the platen roller 53. In that case, first, the leading edge of the paper 50
It contacts one of the correction levers 56. In this state, the platen roller 53 continues to rotate, so that the paper 50
And the platen roller 53 are slipped, the inclination of the sheet 50 is corrected, and the leading end of the sheet 50 contacts both of the correction levers 56. Therefore, for example, the correction lever 56 is moved to the platen roller 53 only for a certain period after the sheet 50 is detected by the sheet detection unit 57 realized by a reflection type optical sensor or the like.
The inclination of the sheet 50 is corrected by bringing the sheet 50 into contact with the rubber roll portion to prevent the sheet 50 from advancing.

When the inclination of the sheet 50 is corrected, the correction lever 56 is rotated by the driving means 58 in the direction away from the rubber roll portion of the platen roller 53. As a result, the sheet 50 is again conveyed by the platen roller 53 and is sent to the print start position.

[0005]

In such a conventional sheet inclination straightening apparatus, the straightening lever 56 is brought into contact with the rubber roll portion of the rotating platen roller 53 during straightening.
As a result, the progress of the sheet 50 is reliably prevented, and the effect of correcting the inclination is high. On the other hand, the rubber roll portion of the platen roller 53 is gradually moved by the correction lever 56 as the number of prints increases. It is scraped. Therefore, there is a problem that rubber pieces are scattered and accumulated inside the thermal transfer color printer, and the inside of the printer must be regularly cleaned and the platen roller 53 must be replaced.

The present invention was devised in view of the above circumstances, and provides a sheet inclination correcting device which can surely correct the inclination of a sheet by using a platen roller and can prevent the platen roller from being scraped. The purpose is to

[0007]

SUMMARY OF THE INVENTION A sheet inclination straightening apparatus according to the present invention is configured to prevent a sheet from being pushed by a rubber roll portion of a platen roller included in a thermal transfer color printer and receiving a propulsive force from the rubber roll portion by a stop member. A sheet tilt straightening device that blocks and corrects the skew of the sheet, and the restraining member is retracted to a position where the sheet passes after the straightening, wherein the restraining member does not contact the rubber roll portion of the platen roller during the straightening, In addition, it is characterized in that it is held at a position that can prevent the progress of the paper.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing the basic structure of a thermal transfer color printer, FIG. 2 is a block diagram showing the electrical structure of a thermal transfer color printer, and FIG. 3 is a side view showing the principal parts of a paper skew correction apparatus according to the present invention. FIG. 4 is a front view showing a main part of the sheet inclination correcting device according to the present invention.

The thermal transfer color printer is composed of a single sheet of paper 50.
Transfer the color image to the. The paper 50 is the guides 1, 2
And the guides 5 by the paper feed rollers 3 and 4,
It is sent to the platen roller 7 from between 6. The platen roller 7 is combined with a pair of left and right straightening levers 8 which are a stopping member of the sheet tilt straightening device. Further, around the platen roller 7, in order to press the sheet 50 against the outer peripheral surface of the platen roller 7 and convey it, a plurality of pressure roller 9
a to 9f are provided.

As shown in FIGS. 3 and 4, the platen roller 7 includes a rubber roll portion 7b supported by a shaft 7a and disc-shaped positioning plates 7c joined to both end surfaces thereof.
7c and. The positioning plate 7c has a smaller diameter than the rubber roll portion 7b and is supported by the shaft 7a. The straightening lever 8 rotates about a shaft 10 as a fulcrum, and its tip 8a
Has an L-shaped cross section, and contacts the positioning plate 7c from below with a slight gap G between both ends of the rubber roll portion 7b. The gap G is made sufficiently smaller than the thickness of the paper 50.

A guide 11 is provided in front of the straightening lever 8, and a paper detection sensor 1 realized by a reflection type optical sensor or the like is provided between the guide 11 and the pressure roller 9a.
2 are provided. The similar paper detection sensor 13 is also arranged on the downstream side of the pressure roller 9b.

The tip end 8a of the straightening lever 8 which is a restraining member of the sheet inclination straightening device is pressed against the positioning plate 7c by a spring 14. The base end of the straightening lever 8 is connected to the lever 16 by a pin 15. The lever 16 is rotated by a spiral groove provided in the cam 17 so as to rotate the correction lever 8 in a direction in which the tip portion 8a of the correction lever 8 moves away from the positioning plate 7c. 18 is a motor for rotating the platen roller 7,
Reference numeral 19 is a motor for rotating the cam 17.

The paper 50 sent to the platen roller 7 is
The pressure roller 9a presses against the rubber roll portion 7b of the platen roller 7, and the rubber roll portion 7b is conveyed by friction with the rubber roll portion 7b. At this time, the tip portion 8a of the correction lever 8 is
A gap G, which is sufficiently smaller than the thickness of the sheet 50, is formed between the rubber roll portion 7b and both ends thereof, and the positioning plate 7
It is pressed against c from below. Therefore, the paper 50
Hits the tip surface of the straightening lever 8 and stops. At this time, if the front end of the paper 50 is inclined with respect to the axis of the platen roller 7, the front end of the paper 50 is first corrected.
Abut the tip surface of. The platen roller 7 continues to rotate even after the tip of the sheet 50 comes into contact with the tip surface of one of the straightening levers 8, causing slippage between the sheet 50 and the platen roller 7 and correcting the inclination of the sheet 50. As a result, its tip comes into contact with both correction levers 8.

When the inclination of the sheet 50 is corrected in this way, the tip portion 8a of the correction lever 8 is fixed to the positioning plate 7.
The correction lever 8 rotates in a direction away from the
To the downstream side. This timing is determined based on the time when the paper detection sensor 12 detects the leading edge of the paper 50. The paper 50 that has finished the correction of the inclination is the pressure roller 9
The sheet is pressed by the platen roller 7 by b to 9f and conveyed, and printing is performed at the print start position 20.

In the printing operation, the ink sheet 21 is moved by the thermal head 22 to the paper 50 on the platen roller 7.
It is carried out by pressing the ink of the ink sheet 21 onto the paper 50 by pressing it against. Thermal head 22
Are attached to the head holder 23. The head holder 23 is rotated by the cam 17 that rotates the correction lever 8 to move the thermal head 22 toward and away from the platen roller 7. Reference numeral 24 is a supply reel for the ink sheet 21, 25 is a take-up reel for the ink sheet 21, and 26 is a motor for rotating the take-up reel 25.

As shown in FIG. 2, the electrical construction of the thermal transfer color printer is such that the print information input means 27, which is realized by a random access memory or the like, gives print information to a control unit 28 which is realized by a microcomputer or the like. It has become. The control unit 28 controls the thermal head 22.
To print. It also controls the motor 18 that drives the platen roller 7, the motor 19 that drives the cam 17, and the motor 26 that drives the take-up reel 25. At this time, the outputs of the paper detection sensors 12 and 13 are used as timing signals.

[0017]

As described above, in the case of the sheet inclination straightening device of the thermal transfer color printer according to the present invention, the restraining member does not come into contact with the rubber roll portion of the platen roller during the straightening and is held at a position where the progress of the sheet can be prevented. Therefore, the inclination of the sheet is surely corrected and the platen roller is prevented from being scraped. Therefore, the situation where the rubber pieces are scattered and accumulated inside the thermal transfer color printer can be avoided, and the frequency of cleaning inside the printer can be reduced. Also, the frequency of replacing the platen roller can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a side view showing a basic configuration of a thermal transfer color printer.

FIG. 2 is a block diagram showing an electrical configuration of a thermal transfer color printer.

FIG. 3 is a side view showing a main part of the paper skew correction device according to the present invention.

FIG. 4 is a front view showing a main part of the paper skew correction device according to the present invention.

FIG. 5 is a side view of a conventional sheet tilt correction device.

FIG. 6 is a front view of a conventional sheet tilt correction device.

FIG. 7 is a side view showing an operation of a conventional sheet tilt correcting device.

[Explanation of symbols]

 7 Platen Roller 7b Rubber Roll 7c Positioning Plate 8 Straightening Lever (Stopping Member) 8a Tip 21 Ink Sheet 22 Thermal Head 50 Paper

Claims (1)

Claim: What is claimed is: 1. A platen roller provided in a thermal transfer color printer is pressed by a rubber roll portion, and a stopping member prevents the paper sheet from receiving a propulsive force from the rubber roll portion, thereby correcting the inclination of the paper sheet. A sheet inclination straightening device in which the restraint member is retracted to a position where the sheet passes after straightening, and the restraint member does not come into contact with the rubber roll portion of the platen roller at the time of straightening, and the sheet can be prevented from advancing. A sheet inclination correction device for a thermal transfer color printer, which is held by