JP2001354338A - Sheet carrying mechanism of printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet carrying mechanism of a printer capable of guiding and carrying sheets highly precisely without position shift even if there is a variety in the width, etc., of the sheets. SOLUTION: In the sheet carrying mechanism, the width D of a pair of guide members 4 is smaller than the width E of a sheet 3. Each guide member 4 has a restricting part 5 for restricting the curving direction of left or right edge 3a or 3b of the sheet 3. The left and right edges 3a and 3b of the sheet 3 are curved in the same direction with the restricting parts 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport mechanism of a printer, and more particularly, to a paper transport mechanism of a printer which can prevent a paper sheet from being conveyed while being transported.

[0002]

2. Description of the Related Art An apparatus using a paper transfer mechanism of a conventional printer in a thermal transfer printer will be described with reference to FIG.
Paper 13 sandwiched between transport roller 11 and driven roller 12
Is transported by a rotation of the transport roller 11 between a thermal head (not shown) in a head-up state and a platen roller (not shown) disposed downstream of the transport roller 11 in the transport direction of the paper 13. I do. An ink ribbon (not shown) is disposed between the thermal head and the paper 13. Then, the thermal head is moved down to selectively heat the plurality of heating elements of the thermal head based on the print information, and returned to the upstream side of the transport roller 11 in the transport direction of the paper 13 by the rotation of the transport roller. Thus, a desired image is printed on a sheet.

If the image to be printed on the paper 13 is a color image, the paper 13 is repeatedly moved back and forth to the downstream and upstream sides of the transport roller 11 to print different color inks on the paper in an overlapping manner. Desired color image on paper 13
It can be printed on. The left and right ends in the width direction of the paper 13 during such reciprocating movement are guided by the guide member 14.

[0004]

However, the paper transport mechanism of the conventional printer as described above has a gap between the left and right ends of the paper 13 being transported and the guide member 14 due to variations in the width and the like of the paper 13. In some cases, a gap having a dimension A was generated. If the paper 13 is transported in such a state that the gap A is generated, the paper 13 may play in the direction of the arrow B or the direction of the arrow C, and the print quality may be degraded.
This problem may occur particularly when a color image is printed, such as when the paper 13 is reciprocated and reprinted.

The present invention has been made in view of the above-described problems, and can guide a sheet without displacement and transport it with high accuracy even if the width of the sheet varies. An object of the present invention is to provide a paper transport mechanism of a printer.

[0006]

According to a first aspect of the present invention, there is provided a paper transport mechanism for a linter, comprising: a pair of guide members capable of guiding a sheet being transported in a width direction; A guide roller includes a transport roller and a driven roller capable of transporting the paper in a state where the paper is guided in the width direction of the paper, the width dimension of the pair of guide members is made smaller than the width dimension of the paper, and the transport roller and While the sheet is being conveyed by the driven roller, the left and right ends in the width direction of the sheet are curved by the guide member.

As a second means for solving the above-mentioned problem, a regulating portion for regulating a bending direction of the left and right end portions of the sheet is formed on the guide member, and the regulating portion forms the sheet on the sheet. The left and right ends are configured to bend in the same direction.

As a third means for solving the above-mentioned problem, the regulating section forms an inclined surface which is inclined at a predetermined angle in a direction in which the right and left ends of the paper are to be curved. The left and right ends of the sheet are curved along the inclined surface.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A paper transport mechanism of a printer according to the present invention will be described below with reference to FIGS. First, FIG. 1 is a sectional view of an essential part for explaining an embodiment of the present invention.
FIG. 3 is a plan view of a sheet according to the present invention, FIG. 3 is a schematic view of a printer according to the present invention, and FIG. 4 is a cross-sectional view of a main part illustrating another embodiment of the present invention.

An embodiment of the paper transport mechanism of the printer according to the present invention will be described with reference to FIG. 1. First, a transport roller 1 rotatable by transmitting rotation from a driving source (not shown).
And a driven roller 2 which is in elastic contact with the transport roller 1 and is rotatable in conjunction with the rotation of the transport roller 1.
Between the transport roller 1 and the driven roller 2 in the elastic contact state, the paper 3 sent from a paper supply unit (not shown) is pressed and held. By rotating the transport roller 1, the paper 3 can be transported in a direction orthogonal to the paper surface shown in FIG.

The paper 3 pressed and held between the transport roller 1 and the driven roller 2 is formed by a pair of guide members 4 having left and right ends 3a and 3b arranged at a width D in the width direction. It is being guided. The width dimension D is formed smaller than the width dimension E of the sheet 3 shown in FIG. Therefore, when the left and right ends 3a and 3b of the paper 3 being conveyed are guided by the guide member 4, the left and right ends 3a and 3b are curved upward or downward in the drawing. Also,
The guide member 4 is provided with a regulating portion 5 for regulating the bending directions of the left and right end portions 3a and 3b of the sheet 3. The restricting portion 5 is formed with an inclined surface 5a for curving the left and right end portions 3a and 3b of the sheet 3 upward in the drawing at a predetermined angle.

The paper 3 is conveyed while being guided by the guide member 4, so that the left and right ends 3a, 3b can be curved in the same direction upward in the drawing along the inclined surface 5a. The restricting portion 5 is not limited to the inclined surface 5a having a predetermined angle, and although not shown, the left and right end portions 3a, 3b
May be formed in an arc in a direction in which is to be curved.

By bending the left and right end portions 3a and 3b of the sheet 3 in the same direction, a restoring force (elastic force) for returning the sheet 3 to its original flat state acts on the sheet 3. Due to this return force, a force acts to move the left and right ends 3a, 3b of the sheet 3 toward the center, which is the center of the sheet 3. Therefore, the paper 3 being transported can be prevented from being transported in the width direction, and high-quality printing can be performed without printing deviation when printing is performed by the thermal head 6 described later.

A printer using the above-described paper transport mechanism will be described as a thermal transfer printer, for example, as shown in FIG. 3. When a transport roller 1 and a driven roller 2 are disposed on the left side of FIG. A thermal head 6 and a rotatable platen roller 7 are provided below the thermal head 6. The thermal head 6 and the platen roller 7
The ink ribbon 8 coated with a desired color ink is accommodated in a ribbon cartridge (not shown).

In the thermal transfer printer as described above, paper 3
In order to print a desired image on the paper, first, the paper 3 is fed from a paper feeding unit (not shown) in the direction of arrow J, and the front end 3 c is located between the transport roller 1 and the driven roller 2. Is pressed and held. Then, by rotating the transport roller 1 in the counterclockwise direction and rotating the driven roller 2 following the rotation of the transport roller 1, the paper 3 moves downstream of the transport roller 1 in the transport direction indicated by the arrow J. Conveyed.

At this time, the front head 3c of the paper 3 passes between the thermal head 6 in the head-up state and the platen roller 7 and is further transported in the transport direction of arrow J. When the trailing end 3d of the sheet 3 reaches the vicinity of the transport roller 1, a sheet end detecting sensor (not shown) detects the trailing end 3d, and the thermal head 6 is moved to the platen roller 7 side. Then, the paper 3 and the ink ribbon 8 are pressed and held between the thermal head 6 and the platen roller 7 to selectively generate heat on a plurality of heating elements of the thermal head 6 based on the print information. Ink ribbon 8
Is thermally transferred to the paper, and the transport roller 1 is rotated in the clockwise direction to return the paper 3 in the direction of the arrow H opposite to the transport direction of the arrow J, thereby printing a desired image on the paper 3. can do.

When the paper 3 is returned in the direction of the arrow H during the printing operation, the left and right ends 3a and 3b of the paper 3 are curved upward by the inclined surface 5a of the regulating portion 5, so that the paper 3 Of the paper 3 in the width direction can be prevented by the returning force acting on the left and right ends 3a and 3b of the paper 3 to return to the flat shape.

If the image to be printed on the paper 3 is a color image, the thermal head 6
Is transported again in the transport direction of arrow J, and the ink of the ink ribbon of a different color is thermally transferred onto the image formed by the first printing. By repeating such a printing operation, reciprocating conveyance is performed to the downstream side and the upstream side of the thermal head, and a desired color image can be printed by overlaying and printing inks of different colors on paper. ing. Even if the paper 3 is repeatedly moved back and forth when printing such a color image, the left and right ends 3a and 3b of the paper 3 are curved in the same direction by the regulating portion 5, so that the paper 3 is not shifted in the width direction. Transport can be performed with high accuracy.

As shown in FIG. 3, the right and left end portions 3a of the sheet 3 curved upward by the regulating portion 5 of the guide member 4,
When the sheet 3b comes off the guide member 4 indicated by the two-dot chain line, the sheet 3 returns to its original flat shape due to the restoring force of the sheet 3, so that the printed sheet 3 does not warp.

As another embodiment of the present invention, as shown in FIG. 4, a downwardly inclined surface 9a is formed on the regulating member 9, and the left and right end portions 3a of the sheet 3 are formed by the inclined surface 9a. , 3b may be curved downward. In other words, the regulating section 5 (or 9)
a, 3b are formed at a predetermined angle in the direction in which the sheets 3 and 3b are to be curved, and the left and right end portions 3a and 3b of the sheet 3 are curved along the inclined surface 5a (or 9a). It is like that. Further, in the embodiment of the present invention, the guide member 4 and the restricting portion 5 are described as being formed as separate members. However, the restricting portion 5 may be formed integrally with the guide member 4.

[0021]

As described above, in the paper transport mechanism of the printer according to the present invention, the width of the pair of guide members is made smaller than the width of the paper, and the paper is transported by the transport roller and the driven roller. Since the left and right ends of the sheet in the width direction are curved by the guide member, the left and right ends of the curved sheet can be prevented from being displaced in the width direction of the sheet being conveyed. A paper transport mechanism of a printer capable of printing can be provided.

Further, a regulating portion for regulating the bending direction of the left and right ends of the sheet is formed on the guide member, and the right and left ends of the sheet are curved in the same direction by the regulating portion. In this way, it is possible to prevent the paper being conveyed from shifting in the width direction.

Further, the regulating portion forms an inclined surface which is inclined at a predetermined angle in a direction in which the right and left ends of the sheet are to be curved, and curves the left and right ends of the sheet along the inclined surface. As a result, even if the sheet is repeatedly reciprocated, the left and right ends of the sheet can be reliably curved on the inclined surface, and a high-quality color image can be printed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part for describing an embodiment of the present invention.

FIG. 2 is a plan view of a sheet according to the present invention.

FIG. 3 is a schematic diagram illustrating a printer according to the invention.

FIG. 4 is a cross-sectional view of a principal part explaining another embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a main part of a paper transport mechanism of a conventional printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Half twin roller 2 Follower roller 3 Paper 3a Left end 3b Right end 3c Front end 3d Rear end 4 Guide member 5 Restriction 5a Inclined surface 6 Thermal head 7 Platen roller 8 Ink ribbon

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazunari Takeda 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. F-term (reference) 2C059 DD02 DD07 DD14 DD27 3F049 AA02 DA11 EA17 LA07 LB03 3F053 HA01 HA06 HB12 LA07 LB03 3F101 FA01 FA06 FB14 FC18 LA07 LB03 3F102 AA11 AB01 BA02 BB04 EA03 FA07

Claims (3)

[Claims] A pair of guide members capable of guiding the width direction of the paper being transported, a transport roller and a driven roller capable of transporting the paper in a state where the guide member guides the paper in the width direction. The width dimension of the pair of guide members is made smaller than the width dimension of the paper, and the right and left ends in the width direction of the paper are curved by the guide members while the paper is being transported by the transport roller and the driven roller. A paper transport mechanism for a printer, wherein 2. A method according to claim 1, wherein a regulating portion for regulating a bending direction of the left and right ends of the sheet is formed on the guide member, and the right and left ends of the sheet are curved in the same direction by the regulating portion. The paper transport mechanism of a printer according to claim 1, wherein: 3. The regulating section forms an inclined surface which is inclined at a predetermined angle in a direction in which the right and left ends of the sheet are to be curved, and curves the left and right ends of the sheet along the inclined surface. 3. The paper transport mechanism of a printer according to claim 2, wherein the paper transport mechanism is configured to cause the paper transport mechanism.