JP3345911B2 - Serial impact printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a serial impact printer, and more particularly to a structure of a serial impact printer for applying tension to printed paper by using a tension roller, and more particularly, to a paper intended to reduce noise. Regarding the guide structure.

[0002]

2. Description of the Related Art A conventional serial impact printer according to the present invention will be described below with reference to FIG.

FIG. 4 is a sectional view schematically showing a conventional serial impact printer. 1 is a platen, 2 is a tension roller, and 3, 4, and 5 are paper press rollers.

The platen 1 and the tension roller 2 rotate in the directions of arrows A and B, respectively, and convey the sheet P in the direction of arrow C. Reference numeral 6 denotes a paper holding plate for preventing the paper P from floating on the upstream of the printing unit, and is urged toward the platen 1. Reference numeral 7 denotes a paper guide, and reference numerals 8 and 9 denote paper guides for guiding the leading edge of the printed paper P to the tension roller 2. Reference numeral 10 denotes an impact dot head, and reference numeral 11 denotes a carriage on which the impact dot head 10 is mounted and which is guided by guide shafts 12 and 13 and moves vertically on the paper along the platen 1. 14
Is integrally attached to the carriage 11, and the platen 1
And a guide member for guiding the paper P along the outer periphery of the platen 1 in a portion opposed to the impact dot head 10, that is, in the vicinity of the printing portion. The guide surface 14 of this guide member is
The leading end of the sheet P is guided along the platen 1, and then the platen 1 is guided in the direction of the tension roller 2.
And a tangent line connecting the platen 1 and the tension roller 2 with a slight gap.

In the conventional serial impact printer having such a configuration, the tension roller 2 is driven at a peripheral speed slightly higher than the peripheral speed of the platen 1. This assists the paper transport by the platen 1 and at the same time imparts an appropriate tension to the paper P, thereby preventing the paper from floating and reducing noise generated during printing. A plurality of tension rollers 2 are installed in parallel along the axial direction of the platen 1. At the time of printing, the guide member 14 is not in contact with the paper P as shown in FIG.

[0006]

However, such a serial impact printer has the following problems.

In general, a serial impact printer uses a sheet of about 4 inches to about 16 inches, but only a plurality of tension rollers 2 are installed in parallel along the axial direction of the platen 1 as described above. is there. For this reason, when considering the distribution of the tension in the width direction of the sheet P, an appropriate tension is applied to a portion where the tension roller 2 is provided, but an appropriate tension is not applied to a portion where the tension roller 2 is not provided. 1
Paper floated between the paper and the paper, and the paper fluttered during printing.

If a wide continuous tension roller is used in the same manner as the platen 1 in order to make the tension uniform, the cost of parts becomes high and it is difficult to reduce the price. Since polishing was required, the diameter of the tension roller could not be reduced, and miniaturization was difficult.

When the paper conveying force of the tension roller 2 is increased in order to secure the tension in the portion where the tension roller 2 is not provided, the peripheral speed of the tension roller 2 is higher than the peripheral speed of the platen 1, Between the paper P and the paper P, it is difficult to secure appropriate paper transport accuracy. In particular, when a continuous form is used by a push-type tractor or the like, since the paper pressing rollers 3 and 4 are released and used, slipping is more likely to occur between the platen 1 and the paper P, which causes troubles such as climbing over a pin. Had occurred.

Accordingly, an object of the present invention is to provide a low-noise serial impact printer which can be reduced in cost and size and has good paper conveyance accuracy.

[0011]

In order to achieve the above object, a serial impact printer according to the present invention is located downstream of a portion where a platen and an impact dot head face each other in a paper feeding direction, and applies tension to the paper. a tension roller for discharging, to abut on the tension roller
A serial impact printer comprising a paper holding roller, and a guide member that moves integrally with the impact dot head and guides the paper along the platen in the vicinity of the opposing portion between the platen and the impact dot head. The tension roller and the paper presser
It is characterized in that it protrudes to the platen side beyond a common tangent line between the nip point with the roller and the platen. Also, near the tension roller, the printing surface side of the paper and
The first paper guide and the second paper guide provided on the back side
The guide section is formed at the leading edge of the paper.
To the nip point between the tension roller and paper press roller
In the transport direction upstream.
It is a feature . Also, the tip of the guide member is
The first paper guide and the second paper plan constituting a guide unit
Between the inside and the predetermined direction in the vertical direction of the guide surface of each guide member
Make sure that they are arranged so that they
2. The serial impact pre-charge according to claim 1, wherein
Nta. Further, the peripheral speed of the tension roller is set higher than the peripheral speed of the platen.

[0012]

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to FIGS.

FIG. 1 is a sectional view schematically showing a serial impact printer according to the present invention. 1 is a platen, 2 is a tension roller, and 3, 4, and 5 are paper press rollers. The platen 1 and the tension roller 2 rotate in the directions of arrows A and B, respectively, and convey the sheet P in the direction of arrow C. The tension rollers 2 are driven at a peripheral speed slightly higher than the peripheral speed of the platen 1, and a plurality of the tension rollers 2 are arranged in parallel along the axial direction of the platen 1. Reference numeral 6 denotes a paper holding plate for preventing the paper P from floating on the upstream of the printing unit, and is urged toward the platen 1. 7 is paper guide, 8 and 21 are paper printing
This is a paper ejection guide provided on the front side and the back side for guiding the leading end of the printed paper P to the tension roller 2 , both of which are transported.
It is arranged so as to expand toward the direction upstream. 10
Reference numeral denotes an impact dot head, and reference numeral 11 denotes a carriage on which the impact dot head 10 is mounted and moves in a direction perpendicular to a guide axis.

Reference numeral 20 denotes a guide member which is integrally attached to the carriage 11 and guides the paper P along the outer periphery of the platen 1 in a portion where the platen 1 and the impact dot head 10 are opposed to each other, that is, in the vicinity of the printing portion. The guide surface 20
Reference numeral 1 denotes a shape along the outer shape of the platen so that the leading end of the sheet P is guided along the platen 1 and then guided toward the tension roller 2. The leading end 202 of the guide member 20 on the tension roller side 2 is located closer to the platen 1 than the paper path between the platen 1 and the tension roller 2 as shown in FIG. 1, that is, the tangent T connecting the two ( see FIG. 3 ) . It protrudes slightly. This tip 202 is similar to that shown in FIG.
As shown in the figure, the projection is located at least above the print wire assignment section 203 of the impact dot head 10 and protrudes toward the platen 1 side. As shown in FIG. 3, the guide surface 211 of the sheet discharge guide 21 is configured such that the leading end of the sheet P facing the platen 1 by the guide surface 201 of the guide member 20 is connected to the tension roller 2.
And the tip 202
A predetermined interval in the vertical direction of the guide surface 211 of the paper ejection guide 21
Is provided so as to overlap with the paper ejection guide 21.
Thus, the leading end of the sheet P is guided as shown by a broken line P1 in FIG.
In FIG. 3, a dashed line T is a tangent line connecting the platen 1 and the tension roller 2.

In the serial impact printer having such a configuration, the state of the paper P at the time of printing is such that the portion of the sheet P which is not opposed to the leading end 202 of the guide member 20 is tensioned with the platen 1 indicated by a chain line in FIG. Although the paper path substantially coincides with the tangent line T connecting to the roller 2, the paper P contacts the leading end 202 of the guide member 20 at a portion facing the leading end 202, and is indicated by a solid line in FIG. As shown in the figure, the paper path has an inverted "ku" shape. Therefore, even in a portion where the tension roller 2 where the paper floating occurs conventionally does not exist, the impact dot head 1 comes into contact with the guide member 20 when the impact dot head 1 passes, so that the paper path is formed in an inverted "C" shape. And the tension of the paper P is increased, so that an appropriate tension can be applied and the floating of the paper P can be prevented.

As described above, since the area of the portion of the paper that is in close contact with the platen increases, the fluttering of the paper hit by the print wire of the impact dot head is reduced, and the noise generated therefrom is reduced.

Table 1 summarizes the results of measuring the noise when a letter quality alphabet is printed at about 90 characters / second on a 24-pin serial impact printer. The interval between the tension rollers 2 is about 50 mm,
The tension was set to about 20 g per 50 mm, the noise was measured in accordance with ISO7779 while changing the protrusion amount of the guide member tip 202 from 0 to 3 mm and changing the width of the guide member tip 202 to 10, 25, and 50 mm.

According to Table 1, under the conditions of this experiment, in order to reduce noise, the width of the guide member tip 202 is preferably at least half of the interval between the tension rollers 2, and the protrusion amount is at least 1.0 mm. desirable. If the protrusion amount is 3.0 mm or more, the paper surface immediately after printing and the guide member tip 202
Is strongly rubbed, and printing stains are generated. Therefore, the protrusion amount of the guide member tip 202 is not less than 1.0 mm and not more than 2.5 mm.
The following is desirable.

[0020]

[Table 1]

[0021]

According to the present invention, the following effects can be obtained.

A part of the guide member which moves integrally with the impact dot head projects to the platen side and comes into contact with the paper, and the tension is applied to the paper by making the paper path of the contact portion into an inverted "-" shape. Therefore, it is possible to prevent the floating of the paper downstream of the printing unit by increasing the number of rollers, so that even if a plurality of tension rollers are installed in parallel along the axial direction of the platen, an appropriate tension is applied downstream of the printing unit. Therefore, even if a tension roller having a small diameter and a small diameter is used, noise can be reduced, and a low-cost, small-size, low-noise serial impact printer can be provided. In addition, since the paper float can be prevented without increasing the paper transport force of the tension roller more than necessary, a good paper transport can be achieved without lowering the paper transport accuracy or jumping over a pin when a push type tractor is used. And a low-noise serial impact printer capable of performing the above operations.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a serial impact printer according to the present invention.

FIG. 2 is an external perspective view of the guide member of the embodiment.

FIG. 3 is a schematic sectional view illustrating a paper path of the embodiment.

FIG. 4 is a schematic cross-sectional view of a conventional serial impact printer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 platen 2 tension roller 3, 4, 5 paper press roller 6 paper press plate 7 paper guide 8, 9 discharge paper guide 10 impact dot head 11 carriage 12, 13 guide shaft 20 guide member 202 tip (projection) 21 discharge Paper guide P paper

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 15/16 B41J 13/00 B41J 13/10 B65H 5/36 B65H 29/52

Claims (4)

(57) [Claims] 1. A and the tension roller located in the paper feeding direction downstream side of the portion facing the platen and the impact dot head, and discharged to give tension to the sheet, the extensible
And a guide member that moves integrally with the impact dot head and guides a sheet along the platen in the vicinity of an opposing portion between the platen and the impact dot head. In the serial impact printer, the leading end of the guide member may be in front of the tension roller.
A serial impact printer wherein the nip point with the paper pressing roller and a common tangent to the platen are projected to the platen side. 2. A sheet of paper is provided near the tension roller.
A first paper guide and a second paper guide provided on the printing side and the back side, respectively.
And a guide portion comprising a paper guide of
The leading edge of the paper with the tension roller and the paper holding roller.
To the upstream side in the transport direction to guide to the nip point with the roller
2. The series according to claim 1, wherein
Al impact printer. 3. The guide member according to claim 1, wherein said guide member has a distal end portion provided with said guide member.
Of the first paper guide and the second paper guide constituting
Between the guides of each paper guide in the vertical direction.
And are arranged to overlap in the transport direction.
2. The serial impact printer according to claim 1, wherein: 4. The serial impact printer according to claim 1, wherein a peripheral speed of said tension roller is set higher than a peripheral speed of said platen.