JP2000247513A - Paper sheet guiding unit and printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the catching of the tip or perforation of a printing paper sheet to the gap in an opening recess. SOLUTION: In this paper sheet guiding unit, driven rollers 6 and 7 held by means of a roller holder 15 are provided in an opening recess 4C provided on a paper sheet guiding surface in a paper sheet guiding unit body 4, to guide printing paper sheets in a paper sheet carrying direction while nippedly holding the printing paper sheets by the rollers 6 and 7 and platens opposite to the rollers 6 and 7, and the holder 15 is formed into a shape along a paper sheet carrying direction at the upper surface 15B of the holder 15, to form the holder tip part 15A near to the upstream side inner wall surface 16 of the recess 4C. The tip of the printing paper sheet being carried on the paper sheet guiding surface of the unit body 4 can be received by the upper surface 15B of the tip part 15A, thereby guiding the tip to the driven roller 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper guide unit for guiding print paper to a platen, and a printing apparatus equipped with the paper guide unit.

[0002]

2. Description of the Related Art Conventionally, a printing apparatus in which printing paper is wound around a cylindrical platen to feed the paper has a driven roller which is elastically contacted with the platen, and the platen is rotated by a fixed angle by a driving source such as a motor. On the other hand, the driven roller is elastically contacted with the peripheral surface of the platen by an elastic urging means such as a spring. The printing paper is sandwiched between a platen and a driven roller, and is fed by the frictional force. When a continuous sheet having a feed hole such as a field sheet is used, as shown in Japanese Utility Model Publication No. Sho 60-145048, a sheet transport device including a sprocket or a tractor is used.

[0006] In order to guide printing paper to a platen, a paper guiding unit is usually provided below the platen. An opening recess is formed in the paper guide unit, and a driven roller is disposed according to the opening recess. The printing paper can be guided in the paper transport direction while nipping the printing paper between the platen and the driven roller, and the printing paper can be wound around the outer peripheral surface of the platen.

[0004]

However, in the above-mentioned prior art, there is a large gap between the inner wall surface of the opening recess formed in the paper guide unit and the roller holder that holds the driven roller. There is a problem that the leading edge of the printing paper is caught in the gap, and paper folding or paper jam occurs. Further, when the printing paper is continuous paper, since there is a perforation (fold), the perforation is caught in the gap, and there is also a problem that a paper break or a paper jam occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper guide unit capable of preventing the leading edge or perforation of printing paper from being caught in a gap between a roller holder and an inner wall surface of an opening, and a printing apparatus equipped with the paper guide unit. It is to provide.

[0006]

According to a first aspect of the present invention, a driven roller held by a roller holder has an opening recess provided on a sheet guide surface of a sheet guide unit body. A paper guide unit provided in the guide roller for guiding the print paper in the paper transport direction while nipping the print paper between the driven roller and a platen opposed thereto, and winding the print paper around the outer peripheral surface of the platen; The top surface of the paper guide unit body is formed so that the upper surface thereof is formed along the paper transport direction, and the upstream end of the holder is formed close to the upstream inner wall surface of the opening recess. It is characterized in that it is formed so that the leading end or the fold of the printing paper conveyed on the guide surface is received on the upper surface of the leading end of the holder and guided to the driven roller. It is intended.

According to the present invention, the tip of the holder of the roller holder is formed close to the inner wall surface on the upstream side of the opening recess, and the tip of the printing paper conveyed on the paper guide surface of the unit body. Is formed so as to be received by the upper surface of the holder leading end portion and guided to the driven roller, so that the leading end of the printing paper does not get caught in the gap of the full-opening concave portion when the paper is conveyed, and the paper breaks or paper jam occurs. Can be prevented from occurring.

According to a second aspect of the present invention, in the paper guide unit according to the first aspect, a first projection is formed on the inner wall surface of the opening recess toward the tip of the holder. It is characterized by the following. According to the present invention, the degree of the approach can be further increased by the first protrusion, that is, the gap can be further reduced, and the catch of the printing paper can be reliably prevented.

According to a third aspect of the present invention, in the paper guide unit according to the second aspect, a guide rib is provided on a paper guide surface of the unit body in a paper transport direction, and the first protrusion is provided. The portion is formed on the inner wall surface in a series with the guide rib. According to the present invention, the printing paper guided and conveyed from below by the guide ribs of the unit main body is further guided by the guide ribs and the series of first rib-shaped projections and received on the upper surface of the roller tip. Therefore, the paper can be smoothly transported in the unit, and the occurrence of the jam can be further prevented.

According to a fourth aspect of the present invention, in the paper guide unit according to any one of the first to third aspects, the second projection facing the roller surface of the driven roller is provided on the inner wall surface of the opening recess. Wherein a portion is formed. According to the present invention, the gap between the outer peripheral surface of the driven roller and the inner wall surface of the opening recess is also reduced similarly to the gap between the roller holder and the inner wall surface of the opening recess. The leading edge or perforation of the paper does not get caught in the gap, and the occurrence of paper breakage and paper jam can be prevented.

According to a fifth aspect of the present invention, there is provided a printing apparatus which has a cylindrical platen, winds a printing sheet around the platen, rotates the platen, and performs printing while feeding the printing sheet. Wherein the paper guide unit according to any one of claims 1 to 4 is mounted. ADVANTAGE OF THE INVENTION According to the printing apparatus concerning this invention, since the paper folding of a printing paper and the occurrence of paper jam can be prevented, it becomes possible to perform printing smoothly.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a longitudinal sectional view showing a paper transport mechanism of a printing apparatus according to the present invention, FIG. 2 is an external perspective view of the paper transport mechanism, FIG. 3 is an external perspective view of a paper guide unit, and FIG.
FIG. 5 is an enlarged sectional view of the paper guide unit, and FIG.
6 is an enlarged perspective view of a main part of the paper guide unit according to the second embodiment.

(Embodiment 1) As shown in FIGS. 1 and 2, the paper transport mechanism of the printing apparatus according to the present invention includes a push-in tractor 1, a printing unit 2, and a paper discharging unit 3. The push-in tractor 1 is provided with two belts 1A. The belt 1A has a large number of pins 1B around it, and these pins 1B fit into holes at both ends of a printing sheet (not shown). The printing paper can be conveyed by rotating the belt 1A with a driving source (not shown). Note that the push-in tractor 1 includes a printing unit 2
Are also provided on the opposite side of.

The printing section 2 is provided with a paper guide unit main body 4 and a cylindrical platen 5. As shown in FIGS. 3 and 4, the upper surface of the paper guide unit main body 4 is a flat surface 4 on the upstream side (upper right side in FIG. 3) along the paper transport direction.
A is provided with a concave curved surface 4B on the downstream side of the flat surface 4A. A plurality of guide ribs 4R that directly support and guide the printing paper are provided on the flat surface 4A and the concave curved surface 4B that form the paper guiding surface in parallel at predetermined intervals in the paper transport direction. The curvature of the concave curved surface 4 </ b> B is substantially equal to the curvature of the platen 5.

In the present embodiment, the paper guide unit main body 4 is formed with four opening recesses 4C along the width direction, and each opening recess 4C is provided with driven rollers 6, 7 along the paper transport direction. It is arranged so as to be rotatable on the roller holder 15. The platen 5 is driven to rotate by a predetermined angle by a driving source (not shown), and conveys the printing paper (not shown) sent from the push-in tractor 1 while nipping it between the driven rollers 6 and 7. . Then, the paper guide unit main body 4 guides the printing paper to the platen 5 side with the concave curved surface 4B, and winds the printing paper around the outer peripheral surface of the platen 5 in a U-shape.

As shown in FIG. 1, a print head 8 is provided to face the outer peripheral surface of the platen 5. The print head 8 is reciprocally movable in a direction perpendicular to the paper surface of FIG.
At the time of printing, printing is performed on the printing paper in close contact with the printing paper wound in a U-shape around the outer peripheral surface of the platen 5.

The paper discharge section 3 is provided with a paper discharge drive roller 9 and a paper discharge driven roller 10. The paper ejection drive roller 9 and the paper ejection driven roller 10 are rotatably supported by the paper ejection unit frame 11. The print paper printed by the print head 8 is conveyed while being sandwiched between the paper discharge drive roller 9 and the paper discharge driven roller 10, and the space 14 between the paper discharge unit frame 11 and the paper discharge unit cover 13 is moved. It is designed to be carried out.

In the present embodiment, the roller holder 15 is
As shown in an enlarged manner in FIG. 5, the upper surface 15B is formed in a shape along the sheet transport direction, that is, a substantially concave curved surface shape. Further, a holder tip 15A, which is located upstream of the roller holder 15 in the sheet transport direction, is formed close to the upstream inner wall surface 16 of the opening recess 4C. With this approach structure, the paper guide surface (flat surface 4) of the paper guide unit main body 4 is formed.
A, the leading end or perforation (fold) of the printing paper conveyed on the concave curved surface 4B) is received by the upper surface of the holder leading end portion 15A and guided to the driven roller 6.

In the present embodiment, the first projection 4 facing the holder tip 15A is provided on the inner wall surface 16 of the opening recess 4C.
D is formed integrally. That is, the first protrusion 4 is provided at a position facing the both end portions 15A of the roller holder 15.
D is formed. Further, the first projection 4D is formed in a rib shape on the inner wall surface 16 in series with the guide rib 4R provided on the paper guide surface of the paper guide unit main body 4. That is, the first protrusion 4D is provided with the opening recess 4C.
Two of them are provided in the vertical direction on the inner wall surface 16 on the upstream side in the transport direction of the printing paper.

As described above, since the first protrusion 4D is formed on the inner wall surface 16 of the opening recess 4C, the roller holder 15
The gap between the leading end portion 15A and the inner wall surface 16 of the opening concave portion 4C becomes small, and the leading end or perforation of the printing paper transported on the paper guiding surface of the paper guiding unit main body 4 is located on the upper surface 15B of the holder distal end portion 15A. The driven roller 6
It is led to. Therefore, it is possible to prevent the leading edge or perforation of the printing paper from being caught in the gap during the paper transport, thereby preventing the printing paper from breaking or a paper jam.

(Embodiment 2) Next, another embodiment will be described. The protruding portion such as the first protruding portion 4D can be formed not only at a position facing the holder tip 15A of the roller holder 15, but also at a position facing the outer peripheral surface of the driven roller 6. That is, in the second embodiment, as shown in FIG. 6, at the position facing the outer peripheral surface of the driven roller 6 on the inner wall surface of the opening concave portion 4 </ b> C, The two protrusions 4E are formed integrally with the sheet transport unit main body 4. Further, a ridge 4F wider than the first protrusion 4D in the first embodiment is formed at a position facing the distal end 15A of the roller holder 15.

With this configuration, the roller holder 15
Not only the gap between the holder tip 15A and the inner wall surface 16 of the opening recess 4C, but also the outer peripheral surface of the driven roller 6 and the opening recess 4C.
The gap between the printing paper and the inner wall surface 16 can also be reduced, and the occurrence of paper folding and paper jam can be more reliably prevented.

In the first and second embodiments, the first projection 4
D, the projection 4F and the second projection 4E
The first projection 4D, the projection 4F
And the second protruding portion 4E are formed of a member different from the sheet transport unit 4, and these are bonded by an adhesive or the like to the inner wall surface 16 of the opening recess 4C.
May be fixed.

[0024]

As described above, according to the present invention,
Since the gap between the holder tip of the roller holder and the inner wall surface of the opening recess is small, the leading edge or perforation of the printing paper does not get caught in the gap when transporting the paper, preventing the occurrence of paper breakage and paper jam. Can be. As a result, printing can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a sheet transport mechanism of a printing apparatus according to the present invention.

FIG. 2 is an external perspective view of the paper transport mechanism of FIG.

FIG. 3 is an external perspective view of a paper guide unit.

FIG. 4 is an enlarged sectional view of the paper guide unit.

FIG. 5 is an enlarged perspective view of a main part of the paper guide unit according to the first embodiment of the present invention.

FIG. 6 is an enlarged perspective view of a main part of a paper guide unit according to a second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 push-in tractor 2 print unit 3 paper discharge unit 4 paper guide unit main body 4C opening concave portion 4D first projection 4E second projection 4F projection 5 platen 6,7 driven roller 8 print head 15 roller holder 15A holder tip

Claims (5)

[Claims] A driven roller held by a roller holder is provided in an opening recess provided on a paper guide surface of a paper guide unit main body, and the driven paper and a platen opposed to the driven roller pinch a print sheet. A paper guide unit that guides in the transport direction and winds the printing paper around the outer peripheral surface of the platen, wherein the roller holder has an upper surface formed in a shape along the paper transport direction and an upstream side thereof. The holder leading end is formed close to the upstream inner wall surface of the opening recess, and receives the leading end or fold of the printing paper conveyed on the paper guiding surface of the paper guiding unit main body on the upper surface of the holder leading end. A sheet guide unit formed so as to guide the driven roller to the driven roller. 2. The paper guide unit according to claim 1, wherein a first protrusion toward the tip of the holder is formed on the inner wall surface of the opening recess. 3. The paper guide unit according to claim 2, wherein a guide rib is provided on a paper guide surface of the paper guide unit body in a paper transport direction, and the first protrusion is formed on the inner wall surface in a series with the guide rib. A paper guide unit, characterized in that: 4. The paper guide unit according to claim 1, wherein a second projection is formed on the inner wall surface of the opening recess toward the roller surface of the driven roller. 5. A printing apparatus having a cylindrical platen, wrapping a printing sheet around the platen, and rotating the platen to feed the printing sheet while performing printing.
A printing apparatus comprising the paper guide unit according to claim 1.