JPH07117291A - Serial dot printer equipment - Google Patents

Abstract

PURPOSE:To prevent occurrence of paper jamming by preventing the edge of a printing medium from being caught by a projecting part so provided on a platen as to be opposed to a dot pin of a printing head. CONSTITUTION:A platen 16 so opposed to a printing head 10 as to hold, together with the printing head, the surface and the rear of the large-width side of a printing medium 32 is constructed so that it runs in the same direction as the printing head 10 synchronously with this head. On the surface of the platen 16, projecting parts 31 are provided at positions being opposite to dot pins 30 in the printing head 10. On the surface side of the platen 16, a projecting and curved regulating part 36 having a little larger height than the height of the projecting parts 31 is provided so as to prevent the edge of the printing medium 32 from being caught by the projecting parts 31 when the printing medium 32 is inserted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head which runs along the surface of a print medium, and is arranged opposite to the print head with the print medium sandwiched therebetween, and in the same direction in synchronization with the print head. The present invention relates to a serial impact printer having a platen configured to move.

[0002]

2. Description of the Related Art Conventionally, an impact printer has placed a set of a plurality of print media on which pressure-sensitive paper such as carbon paper is stacked on the surface of a cylindrical platen, and dot pins are applied from the front side of the print media. It is used when printing all at once with the impact force of. As such a printer,
Recently, a multi-leaf set (so-called multi-part paper) in which a large number of sheets (for example, 10 sheets) are piled up to create a double slip.
There has been a demand for a material that can be printed on the target print medium.

However, when printing on a large number of sheets, there are the following two problems. First, since printing is performed with a sufficient density on the lowermost printing paper, there is a problem that when the printing is performed with a strong printing pressure, the uppermost paper is pierced by dot pin holes. Another problem is that the impact force of the dot pins is dispersed and the printed characters are more likely to be blurred as the lower layer of paper near the platen surface is approached.

In order to solve this problem, the present applicant first disclosed in Japanese Patent Application No. 4-164196 that a platen having a small area is arranged so as to face a print head with a print sheet, which is a print medium, interposed therebetween. An impact printer has been proposed in which the platen is moved in the same direction in synchronization with the print head, and a protrusion is provided on the surface side of the platen so as to face the dot pin of the print head.

According to this structure, when the dot pin applies a striking force to the printing paper, the printing paper is sandwiched between the surfaces of the protrusions having a small cross-sectional area, so that the striking force is not dispersed but concentrated on a small area. To do. As a result, it was possible to clearly print on all the leaves of the printing paper of the multi-sheet set.

[0006]

However, this structure has the following problems. That is, FIG.
As shown in FIG.
Since the gap size between the front surface of the platen 101 and the front surface of the projection block 103, which is arranged to face 00a, is small, the edge of the projection portion 103 protruding from the front surface of the platen 101 when the print medium 102 is inserted in the direction of arrow A In addition, the front edge of the print-receiving medium 102 is caught, so that the paper cannot be fed smoothly and reliably, and so-called paper feeding failure (paper jam) occurs.

In order to solve this problem, the carriage supporting the platen is configured to be movable back and forth with respect to the front surface of the print head, and when the paper is inserted, the front carriage is retracted so that the front surface of the platen and the nose portion of the print head are moved. It is conceivable that the platen is once again approached toward the print head during the printing operation after the distance between the print head and the print head is widened.

However, with such a structure, the structure for moving the carriage becomes complicated, and control for moving the carriage back and forth is also required, which increases the manufacturing cost of the printer device. Further, since it takes a time for moving the platen back and forth, there is another problem that the printing processing speed becomes slow as a whole. Moreover, when the print head and the platen are laterally moved in the direction orthogonal to the paper feeding direction, if the platen is moved beyond the lateral edge of the paper to the outside of the lateral side of the paper, and then returned, the front surface of the platen also remains. The protruding part is caught on the lateral edge of the paper,
The paper jam phenomenon such as tearing the paper could not be resolved.

The present invention has been made in order to solve these problems, and it is an object of the present invention to provide a dot impact printer device having a simple structure, which does not reduce the printing processing speed and does not cause a paper jam. It is intended.

[0010]

In order to achieve the above object, the present invention is directed to a print head which runs along the surface of a print medium and is arranged to face the print head with the print medium sandwiched therebetween. In a serial dot printer device including a platen that runs in the same direction in synchronization with a print head and a protrusion provided on the platen facing a dot pin of the print head, the protrusion is provided on the front surface side of the platen. The height of the protrusion is approximately equal to or higher than the height of the protrusion.

[0011]

EXAMPLES Next, examples embodying the present invention will be described. FIG. 1 is a perspective view of a main part of a serial dot printer, and FIG. 2 is a side view of a main part of the serial dot printer. As shown, a print head 1 in a printer
The first carriage 11 supporting 0 is slidably supported by the main guide shaft 12. An auxiliary guide shaft 14 is loosely fitted in a rearward U-shaped guide groove 13 of the first carriage 11 so as to be movable back and forth toward a platen 16 described later.
The platen 16 is fixed on a support block 34 of the second carriage 15 slidably supported by guide shafts 17 and 18 extending in parallel with the main guide shaft 12.

Pulleys 20, 21 of the same diameter provided on a drive shaft 19 extending in a direction orthogonal to the main guide shaft 12 in the front-rear direction.
The timing belts 22 and 23 wound around are locked to the first carriage 11 and the second carriage 15, respectively, and the drive shaft 19 is driven by a drive motor (not shown) such as a step motor capable of rotating in the forward and reverse directions. The first carriage 11 and the second carriage 15 are configured to reciprocate in synchronization with each other in the same direction.

The first guide 11 and the second carriage 1 are rotated by rotating the main guide shaft 12 forward and backward around an eccentric shaft center provided at the end of the main guide shaft 12.
The front and back surfaces of No. 5 are adjusted for perspective movement so that the printing gap can be adjusted. Print information is transmitted from a control device (not shown) via a flexible printed wiring cable 24 connected to the print head 10, and via a drive mechanism (not shown) including an electromagnetic solenoid or a piezoelectric element built in the print head 10. , Nose portion 10a of print head 10
The dot pins 30 are driven to project toward the protrusions 31 provided on the surface of the platen 16, and the printing operation is performed toward the print-receiving medium 32 that is pressure-sensitive paper such as printing paper. As shown in FIG. 2, an ink ribbon 33 is inserted between the print-receiving medium 32 and the tip surface of the nose portion 10a, and the uppermost sheet of the print-receiving medium 32 is printed by the ink ribbon 33. However, after the second sheet, a copy can be obtained by striking force (impact force) with respect to the pressure-sensitive ink layer applied on the surface of each sheet (the layer coated with microcapsules containing ink particles). ing.

Further, as described above, the first carriage 1
1 and the platen 16 are moved in the same direction in synchronism with the printing operation, thereby causing the dot pin 30 to project.
Therefore, the tip end of is always in a position facing the front surface of the protrusion 31. As shown in FIG. 2, the print-receiving medium 32 includes a pair of paper feed rollers 2 disposed on the upstream side and the downstream side of the conveyance.
The sheets are nipped by 5a, 25b and 26a, 26b, and are fed in a direction intersecting with the moving direction of the first carriage 11 and the second carriage 15 (direction orthogonal to each other, arrow A direction).

In the embodiment shown in FIG. 3, there are a plurality of independent projections 31 projecting from the front surface of the platen 16 and integrally projecting from the base 35 to the front surface of the platen 24.
When viewed from the front, the projections 31 of the book are arranged in a rhombus shape, and the 24 dot pins 30 (not shown) are the projections 31.
Are arranged in a rhombus shape at a position facing the tip surface of the. The first and second carriages 11 and 15 are synchronously moved in the direction of arrow C in FIG. 1 so that the projections 31 are positioned in a one-to-one correspondence with the dot pins 30. .

Then, as in the first embodiment shown in FIG.
On the surface of the platen 16, there are provided laterally elongated projecting restricting portions 36, 36 having convexly curved tips at upper and lower positions apart from the group of the projecting portions 31. Each of these protruding control parts 3
The height dimension H1 of 6 is set to be slightly higher than or equal to the height H2 of the protrusion 31 (see FIG. 4). To explain the printing operation by such a configuration, as shown in FIG. 4, the medium to be printed is printed with the gap between the nose portion 10a of the print head 10 and the front surface of the platen 16 set to the gap dimension H3 in the normal printing operation. When 32 is conveyed in the direction of the arrow A, the tip of the print-receiving medium 32 is guided between the print head 10 and the platen 16 while being guided by the smooth convex curved tip of the protrusion regulating portion 36 on the lower side of the front surface of the platen 16. Since the tip end of the protrusion 31 and the tip of the print medium 32 do not interfere with each other after being inserted, the print medium 32 is smoothly inserted.

During the printing operation, the ink ribbon 33 and the print medium 32, which is a pressure sensitive paper, are positioned between the surface of the platen 15 and the print head 10. When the dot pin 30 projects toward the protrusion 31 in response to the print command,
Since the area of the tip of the protruding portion 31 is substantially the same as the cross-sectional area of the dot pin 30, the pressing force by the impact force of the dot pin 30 extends only to a range approximately equal to the cross-sectional area of the dot pin 30. In other words, unlike the case where the platen has a large area, the impact force of the dot pin 30 does not disperse. From the paper nearer to the paper nearer to the paper nearer to the protrusion 31, approximately the same pressing force is applied, and clear copy printing can be performed on all the papers.

In the second embodiment shown in FIG. 5, when the platen 16 moves in the direction of arrow C with respect to the print medium 32 (not shown), the tip end of the projection 31 protruding from the surface of the platen 16 is the print medium. In order not to get caught on the lateral edge of 32, the platen 16 is vertically long on both left and right sides of the surface,
The projecting restricting portions 37, 37 each having a convexly curved tip are provided. With this configuration, the print head 10
When the platen 16 and the platen 16 move laterally in the direction of arrow C in synchronization with each other and return beyond the lateral edge of the print-receiving medium 32, the lateral edge of the print-receiving medium 32 has a convex curved tip of the projecting regulating portion 37. As a result, the lateral edge of the print-receiving medium 32 is projected toward the protrusion 31.
It is possible to prevent an accident in which the print-receiving medium 32 is damaged by being caught by.

In the third embodiment shown in FIG. 6, a pair of vertically elongated paired projection regulating portions 36, 36 are provided on the surface of the platen 16 so as to surround a group of the projections 31, and a pair of vertically elongated left and right projections. Part 3
7 and 37 are provided. According to this structure, the projections 31 on the surface of the platen 16 have the protrusions 31 on the print medium 32 regardless of the relative movement directions of the print medium 32 (not shown) and the platen 16 in the arrow A direction and the arrow C direction. It does not interfere with.

In the fourth embodiment shown in FIG. 7, the platen 16
On the surface of, the projecting restricting portions 38 each having a hemispherical tip are projected at four positions surrounding the group of the projecting portions 31.
Also in this embodiment, when the print medium 32 (not shown) moves in the direction of the arrow A, the print medium is moved by the pair of left and right projection-shaped restricting portions 38, 38 protruding toward the lower surface portion or the upper surface portion of the platen 16. When guiding the upper edge (lower edge) of 32 and moving the platen 16 laterally in the direction of arrow C,
The medium to be printed 3 is formed by a pair of upper and lower projection-shaped restricting portions 38, 38 projecting to the right side portion or the left side portion of the platen 16.
Since the left and right edges of 2 are guided, it is possible to reliably prevent the print-receiving medium 32 from being caught by the protrusion 31 in any direction.

Although not shown, if the shape of the tip surface of each of the independently protruding protrusions 31 is formed to be longer in the direction of the adjacent protrusions, the protrusions facing the 30 hit dot pins. In the direction in which the shape of the distal end surface of 31 intersects with the longer shape of the distal end surface, the print-receiving medium 32 is largely curved and dented on the outer periphery of the protruding portion. Since the print-receiving medium 32 is supported in a flat shape without being greatly depressed along the line, printing on the paper on the back side of the print-receiving medium is performed on the outer periphery of the projection 31 at a position facing the dot pin 30 that operates to project. There is an effect that the back surface of the print medium is pressed against the tips of the adjacent protrusions so that unnecessary shadows cannot be formed.

The dot pins 30 and the protrusions 31 corresponding thereto may be arranged in an annular shape in a front view, in a zigzag arrangement in two rows, or the like, and the protrusions 31 protruding on the surface of the platen 16 are the above-mentioned ones. Instead of the independent one as in the example,
The dot pins 30 may be formed in a long ridge shape along the arrangement direction, and the ridge restricting portions of the above-described embodiments can be applied to these as well.

Further, as shown in FIG. 8, the second carriage 15 that moves laterally in synchronization with the print head 10 (see FIG. 1).
The print head 10 on the front surface of a support 40 supported by
Forming a recess 41 opening in the direction, and arranging a piezoelectric element 42 formed by stacking a large number of piezoelectric ceramics in the recess 41, and fixing the base end of the piezoelectric element 42 to the support body 40,
The left and right ends of a spring plate 43 adhered to the front end of the piezoelectric element 42 are fixed to the support body 40, and the platen 16 having the projection 31 in each of the above embodiments is fixed to the front surface of the spring plate 43. It is also possible to provide projecting restricting portions 36, 37, 38 on the surface of 16 as shown in each of the above embodiments.

With this structure, the piezoelectric element 42 is synchronized with the impact operation of the dot pin 30 of the print head 10.
When a voltage is applied to the piezoelectric element 42,
The platen 16 and, by extension, the projection 31 apply an impact force from the back surface side of the print medium 32 toward the dot pins 30. Therefore, in combination with the impact force of the dot pins 30, the print medium It is possible to perform clearer printing on 32. The piezoelectric element 4
The voltage is applied to 2 for the number of print media 32 (the number of sheets)
It may be controlled so that it is turned off when the number is small and is turned on only when the number is large. In this way, the platen 16 is mounted via the piezoelectric element 42 mounted on the second carriage 15.
When driven back and forth, the driven parts (platen 16 and spring plate 4
Since the mass of 2) is small, the required energy can be reduced, which can contribute to energy saving and each component can be made compact.

Further, in order to reduce the abrasion of the protrusion 31 due to the repeated impact with the dot pin 30, it is preferable to form the protrusion 31 in each of the above-mentioned embodiments by a member having abrasion resistance. For example, in the case where the base portion 35 and the protrusion portion 31 are integrally formed as shown in FIG.
It is made of wear resistant material such as cemented carbide, high speed steel, alumina ceramics, zirconia ceramics, silicon carbide ceramics, silicon nitride ceramics and artificial ruby.

The surface of the protrusion 31 in each of the above-described embodiments made of ordinary carbon steel or the like is coated with hard chrome having a layer thickness of 5 microns or more and titanium nitride coating or nitriding treatment having a layer thickness of 3 microns or more. Apply or iron alloy (steel, etc.)
The wear resistant layer may be formed by performing induction hardening or carburizing on the above. In each of the above-mentioned embodiments, the protrusions 31 and the protrusion restricting portions 3 which are ridge-shaped or independent
If a block-shaped one formed by integrally or implanting 6, 37, 38 on the base 35 is attached to the surface of the platen 16 or the second carriage 15, material cost and processing It also has the effect of significantly reducing costs and the like. By reducing the height of the protrusion 31, the breakage accident of the protrusion 31 can be reduced.

[0027]

As described above, according to the present invention, the print head which runs along the surface of the print medium and the print head which is disposed so as to face the print head with the print medium sandwiched therebetween. In a serial dot printer device provided with a platen that runs in the same direction in synchronization with the platen, and a protrusion provided on the platen facing the dot pin of the print head, the height of the protrusion on the surface side of the platen. Since a protrusion-shaped restricting portion having a surface that is approximately equal to or higher than the above is provided with a smooth surface, even if the gap between the print head and the platen is small, the print medium is inserted and conveyed in the gap. In some cases, when the platen and the print head move back over the lateral edge of the print medium as a result of the printing operation,
Before the print medium is caught by the projections on the platen surface, the print medium is guided by the tip of which the surface of the protrusion regulating portion is smooth, so that it is possible to prevent the occurrence of paper jam. Since the structure for that purpose is as simple as projecting the protruding restricting portion on the surface of the platen, the manufacturing cost of the dot impact printer can be reduced. Furthermore, unlike the conventional technology, there is no need to move the platen back and forth,
This has an effect that the print processing speed is not reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a printer.

FIG. 2 is a side view of a main part of the printer.

FIG. 3 is a perspective view of a platen surface portion of the first embodiment.

FIG. 4 is an operation explanatory view.

FIG. 5 is a perspective view of a platen surface portion of a second embodiment.

FIG. 6 is a perspective view of a platen surface portion of a third embodiment.

FIG. 7 is a perspective view of a platen surface portion of a fourth embodiment.

FIG. 8 is a perspective view of an embodiment using a piezoelectric element.

FIG. 9 is a diagram for explaining the operation of the prior art.

[Explanation of symbols]

 10 Print Head 11 First Carriage 15 Second Carriage 16 Platen 19 Drive Shaft 20,21 Pulley 22,23 Timing Belt 30 Dot Pin 31 Projection 32 Print Target Medium 33 Ink Ribbon 34 Stand 36, 37, 38 Projection Restriction

Claims (1)

[Claims] 1. A print head which runs along the surface of a print medium, a platen which is arranged so as to face the print head with the print medium sandwiched therebetween, and which runs in the same direction in synchronization with the print head, In a serial dot printer device having a dot pin of a print head and a protrusion provided on a platen facing the dot pin, a surface of the platen having a surface approximately equal to or higher than the height of the protrusion is smooth. A serial dot printer device characterized in that it is provided with a protruding control section.