JP3341917B2 - 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 printer, for example, in a dot matrix impact printer and the like.
In particular, the present invention relates to a flat platen arranged to face a print head.

[0002]

2. Description of the Related Art As shown in FIGS. 8 and 9, a flat-shaped printing platen 1 used in a conventional dot matrix impact printer of this type is formed by plating a surface of a long hole 3 of a frame 2 formed by aluminum die casting. A structure is employed in which the processed elongated platen member 4 is press-fitted with an adhesive.

When the surface of the platen member 4 and the surface of the frame 2 are not finished to a predetermined dimensional accuracy with smoothness, the platen 1 has a dimension between the leading end position of the print head and the surface of the platen member 4. In other words, a large variation occurs in a so-called printing gap, so that not only printing quality cannot be ensured, but also the leading edge of the sheet is caught on the front side edge of the platen member 4 when the sheet is transported, so that the sheet is easily jammed. .

[0004]

In the platen 1 having a structure manufactured by press-fitting the platen member 4 into the frame 2,
There has been a problem that the number of man-hours required for precision machining including secondary machining for securing predetermined dimensional accuracy after forming by aluminum die casting and finishing machining of the platen member 4 is increased, resulting in an increase in cost.

In order to reduce the number of man-hours required for precision machining, it is conceivable to integrally mold a frame made of a synthetic resin material and a platen member formed of a metal material. Various synthetic resins such as a linear PPS resin material mixed with the filler as a filler were examined. The platen obtained by integrally molding the synthetic resin frame and the metal platen member depends on the dimensional manufacturing accuracy of the platen member. Due to the variation, a molding variation, which is a molding flash at the surface side edge portion of the platen member, is likely to occur largely, and there is a quality problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a printer for conveying a sheet between a platen facing a print head and performing printing on the sheet by the print head, the formability of the platen is improved. It is an object of the present invention to provide a printer that can improve the printing quality without the paper being caught on the platen.

[0007]

SUMMARY OF THE INVENTION A printer according to the present invention conveys a sheet between a print head and a platen disposed opposite the print head, and prints the sheet with the print head. A platen member having an inclined surface inclined toward the rear side toward the edge at an edge of the long exposed surface extending in the longitudinal direction,
The platen frame is made of a synthetic resin material that is exposed to the long surface of the long platen member and is insert-molded and held.

[0008]

According to the printer of the present invention, an inclined surface which is inclined rearward toward the edge is formed at an edge extending in the longitudinal direction of the surface where the elongated platen member is exposed, and this platen member is formed of a synthetic resin material. By performing insert molding on the platen frame, it is possible to prevent the formation of burrs on the surface side edge of the platen member due to variations in the manufacturing accuracy of the platen member. No need for machining.

Therefore, the platen can form the surface of the platen member and the surface of the frame with a predetermined dimensional accuracy with smoothness, and not only does not cause a large variation in the printing gap, but also causes the paper to be formed on the surface side of the platen member. The edge of the platen is not caught, the workability of the platen is improved, and the quality of the platen can be secured at low cost.

[0010]

Next, the configuration of an embodiment of the present invention will be described.

1 to 5, reference numeral 10 denotes a platen. The platen 10 is an elongated platen member 11 formed of steel, and a synthetic resin for insert-molding the platen member 11, for example, a wholly aromatic polyester ( (Vectra, Celanese, USA).

The platen member 11 has an exposed surface portion.
The upper and lower edges 13a and 13b along the longitudinal direction of the platen 13 are formed into a substantially U-shaped section having upper and lower edge pieces 14a and 14b bent toward the rear side, and extend along the longitudinal direction of the surface portion 13 of the platen member 11. As shown in FIG. 6, the upper and lower edges 13a, 13b are formed on inclined surfaces 15a, 15b inclined rearward toward the edges. At both ends in the longitudinal direction of the platen member 11, mounting pieces 17 having mounting holes 16 are formed. The lower edge pieces 14b of the edge pieces 14a and 14b are formed shorter.

The frame 12 is provided with the platen member.
A plurality of sheet guide pieces 19 project from the lower edge of the elongated base 18 into which the 11 is inserted, and a sheet guide edge piece 20 shorter than the sheet guide piece 19 projects from the upper edge. Further, screw hole members 21 are provided on both end surfaces in the longitudinal direction of the frame 12 by insert molding.

A mounting hole 23 for fitting and fixing a paper detector 22 is formed in one of the paper guide pieces 19.

Further, in FIG. 1, reference numeral 24 denotes a printer main body. The printer main body 24 is constructed by connecting a pair of main frames 25 arranged on both sides in a state of facing each other. In the vicinity of the lower end on the front side (left side in the figure), which is the operator side between the main frames 25, a cut sheet carry-in port 26 is provided as a sheet carry-in port. A paper outlet 27 is provided between the cut paper inlet 26 and the paper outlet 27 as a transport path curved upward to form an arc having a center of rotation on the front side. One transport path 28 is formed.

A first frame is provided between the main frames 25.
A plurality of lower transport rollers 29 are supported rotatably and reversely along a transport surface 28a on the lower side of the transport path 28, and a first transport path 28 The platen 10 is attached, and a pair of transport rollers 32a and 32b are provided on the upper portion of the platen 10.

A tractor mounting table 33 is formed on the rear side of the main frame 25. A pair of tractor sets 34 for supplying continuous paper to the tractor mounting table 33 are mounted on the tractor mounting table 33. And this tractor set 34
Continuous paper entrance 35 into printer body 24
The second transport path 36 is communicated with the first transport path 28 below the platen 10 along the lower side of the peripheral surface of the main roller 30 from the continuous paper entrance 35. Is provided. A paper pan 37 and a continuous paper transport roller 38 are provided along the lower surface of the second transport path 36.

In the vicinity of the cut-sheet carry-in port 26 at the lower front side of the main frame 25, a rotation shaft 41 constituting a rotation support portion is fixed, and is located near the platen 10, The lock mechanism pin 42 is fixed.

Reference numeral 44 denotes a carriage block. The carriage block 44 is arranged on both sides and is formed by connecting a pair of carrier frames 45 in a state of facing each other.
On the rear surface side of the carriage block 44, an upper transfer surface serving as a curved bonding portion facing a lower transfer surface 28a serving as a bonding portion of the main frame 25 with a gap therebetween.
A plurality of upper transport rollers 47 that rotate in close contact with the main roller 30 and the lower transport roller 29 of the main frame 25 are supported along the upper transport surface 28b. .

A carrier (not shown) is provided above the carriage block 44. A print head 51 and a ribbon cassette 53 are mounted on the carrier so as to be reciprocally movable in the width direction of the paper. 51
Is composed of a dot matrix impact type print head, and the print head 51 has a predetermined accuracy between a print portion 55 facing the platen 10 at the tip and a surface portion 13 of the platen 10 attached to the main frame 25. They are opposed via a printing gap.

At the lower end of the front side of the carrier frame 45, there is provided a bearing portion 56 which constitutes a rotation support portion which is cut out in a substantially U-shape, and this bearing portion 56 is attached to the main frame 25. The carriage block 44 is rotatably attached to the front side of the main frame 25 by being fitted to the rotating shaft 41 of the main frame 25.

Further, a lock mechanism hook 58 is rotatably provided near the upper end of the carriage block 44, and the carriage block 44 is rotated rearward to be in the first position.
1, the lock mechanism hook 58 is connected to the lock mechanism pin 42 of the main frame 25 in the state shown in FIG.
The platen 10 and the print head 51 are opposed to each other with a printing gap of a predetermined accuracy, and the upper transport roller 47 and the lower transport roller 29 are rotated in close contact with each other. In this state, the carriage block 44 is fixed and held at a predetermined position.

Next, the operation of this embodiment will be described.

First, when molding the platen, as shown in FIG. 6, the platen member 11 is mounted on the molding die 65 such that the surface portion 13 of the platen member 11 is exposed in a state of being insert-molded. Molding is performed by filling a resin material from two gates 60a and 60b located at one end in the longitudinal direction of the long platen member 11 of the mold 65, for example, at the rear end. Then, the platen member 11 has upper and lower edges 13 on the front side.
inclined surfaces 15a, 15b inclined to the rear side toward a, 13b
Thus, even if the platen member 11 has a slight variation in manufacturing accuracy due to bending or the like, it is possible to prevent the occurrence of a gap between the molding die 65 and the edges 13a and 13b of the platen member 11 during molding. The synthetic resin does not go around the gap during molding, and the surface side edge of the platen member 11
The formation of molding burrs on 13a and 13b can be prevented.

Further, since the platen member 11 has the mounting pieces 17, 17 at both ends thereof protruding from the end face of the frame 12, the platen member 11 does not shift due to thermal expansion and thermal contraction due to insert molding.

Next, the operation of the printer will be described.

When printing using cut paper,
With the carriage block 44 closed as shown in FIG. 1, cut paper is inserted into the first transport path 28 from the front cut paper carry-in entrance 26. By turning on the paper feed switch in this state, the motor is driven based on a command signal of a drive control unit controlled by a CPU (not shown), and the upper and lower transport rollers 29 and 47 and the main roller are transmitted via the rotation shaft of the motor and the transmission mechanism. The cut paper is transported by rotating 30 or the like, and the cut head is transported to the print gap between the platen 10 and the print head 51, and the print head 51 is moved to the carrier based on the print command signal from the print control unit. Each dot element is output while being reciprocated while being guided, and printing is performed by the print head 51. The cut sheet printed in this way is conveyed by the rollers 29, 30, 47 and the conveying rollers 32a, 32b, and is discharged vertically from the sheet outlet 27.

The paper is printed while the paper is conveyed from above to below by using the upper paper outlet 27 as the paper inlet and the lower paper inlet 26 as the paper outlet, or the paper is reciprocated. It is also possible to print while performing.

Further, when printing is performed using the continuous paper, the paper feed switch is turned on while the continuous paper is set in the rear tractor set 34, so that the tractor set based on the command signal of the drive control unit is set. 34 operates to supply the continuous paper from the continuous paper entrance 35 to the second transport path 36. The continuous paper is transported by the main roller 30 and the continuous paper transport roller 38 while being guided by the paper pan 37, and is transported along the first transport path 28. Then, similarly to the case of the cut sheet, the print is performed by the print head 51 and discharged from the sheet outlet 27.

The surface of the platen member 11 and the surface of the frame 12 of the platen 10 are formed to have predetermined dimensional accuracy with smoothness.
There is no large variation in the printing gap with the surface of 11, the printing quality can be ensured, and the paper can be transported smoothly.

If the paper is left in the first transport path 28 by being caught or the like (paper jam state), the lock mechanism hook 58 of the carriage block 44 is rotated to lock the main frame 25. By rotating the carriage block 44 to the front side in a state where the carriage block 44 is removed from the mechanism section pins 42, the first block between the platen 10 and the print head 51 and between the upper transfer surface 28b and the lower transfer surface 28a is moved. Transport path
Expand and release 28 and remove any paper.

Next, the configuration of the platen 10 according to the printer of the present invention will be described based on the results of experiments. The inventor has determined that the synthetic resin can be used in view of rigidity, deformation, and adhesion to the platen member 11 made of steel. As a result of a comparative experiment on a linear PPS resin material (polysulfide), a PP resin material and an ABS resin using glass fiber as a filler, as shown in Table 1, the linear PP
It was confirmed that the S resin was smaller in shrinkage and the amount of deformation (μmm) of warpage at the center portion than other resin materials, and was the most excellent in deformation resistance.

[0033]

[Table 1] Therefore, the result of insert molding with changing the gate position and the number of gates of the molding die 65 filled with the linear type PPS resin material shows that when the gates are arranged at two places on the left and right sides on the back of the frame 12, There is almost no difference in the amount of deformation between the case where gates are arranged at five equally spaced positions on the back,
It was confirmed that the amount of warpage of the resin-formed platen did not differ depending on the gate position and the number of gates.

[0034]

[Table 2] Then, comparing the results of molding experiments with the linear PPS resin material and a wholly aromatic polyester (trade name: Vectra, Celanese, USA) with gates arranged at five locations on the back, as shown in Table 3, Aromatic polyester is linear PP
The amount of warpage is smaller than that of the S resin material, and the wholly aromatic polyester has a smaller shrinkage in the flow direction of the resin material from the gate during molding than the linear PPS resin material. Presumed.

[0035]

[Table 3] Further, as a result of a molding experiment in which a gate was disposed at one end portion of the linear PPS resin material and the wholly aromatic polyester at one end portion in the longitudinal direction, as shown in Table 4, the wholly aromatic polyester was on the back side. It was confirmed that the amount of deformation was significantly reduced as compared to the case where a gate was arranged at five places and a molding experiment was performed. However, when the linear PPS resin material was filled from one end face in the longitudinal direction, poor flow of the resin material occurred and molding was defective.

[0036]

[Table 4] From these experimental results, the liquid crystal resin material molded into the platen frame 12 has a molecular structure in which the shrinkage of the resin material in the flow direction at the time of molding is extremely small. By filling from one or a plurality of gates 60a and 60b located at one end in the longitudinal direction, the contraction rate of the frame 12 in the longitudinal direction is extremely small, and it is confirmed that there is almost no distortion due to the warpage of the frame. Was.

In the above embodiment, the print head 51 has been described as a print head of a dot matrix impact printer. However, the print head 51 is not limited to a dot matrix impact print head, and may be applied to a thermal print head. it can. When applied to a thermal print head, the surface portion of the platen member 11
The rubber material is subjected to a surface treatment such as coating on 13.

In the above-described embodiment, the elongated platen member 11 has upper and lower edges 13a, 13a along the longitudinal direction of the surface portion 13.
b, inclined surfaces 15a, 15b inclined rearward toward the edge
However, in a printer having a structure in which the sheet is conveyed only in one direction or a structure in which the sheet is not reciprocated, only the inclined surface 15b may be formed on the edge 13b only on the sheet feeding side.

Although the elongated platen member 11 has the surface portion 13 formed in a flat shape, the elongated platen member 11 may have a structure in which the surface portion 13 has a curved surface or an arc surface that protrudes in the width direction with respect to the surface.
The platen member is not limited to a metal such as a steel material, and may be formed of an appropriate material.

[0040]

According to the present invention, in a platen formed by insert-molding a platen member into a synthetic resin platen frame, a molding flash is formed on a surface side edge of the platen member due to a variation in manufacturing accuracy of the platen member at the time of molding. Since the platen does not occur, the formability of the platen is improved, and the platen can be formed with a predetermined dimensional accuracy with smoothness on the surface of the platen member and the surface of the frame, and the paper is caught on the surface side edge of the platen member. Paper jam can be prevented, and the quality of the platen can be ensured at low cost.

[Brief description of the drawings]

FIG. 1 is a side view of a printer showing one embodiment of the present invention.

FIG. 2 is a front view of the platen.

FIG. 3 is a longitudinal sectional view taken along line 2a-a of FIG. 2;

FIG. 4 is a longitudinal sectional view taken along the line bb in FIG. 2;

5A is a longitudinal sectional view taken along the line c-c in FIG. 2 and FIG. 5B is a partially enlarged view.

FIG. 6 is an enlarged sectional view of a part of the platen during molding.

FIG. 7 is a perspective view of the platen.

FIG. 8 is an exploded perspective view of a platen of a conventional printer.

FIG. 9 is a front view of the platen.

[Explanation of symbols]

 10 Platen 11 Platen member 12 Frame 13a, 13b edge 15 Inclined surface 51 Print head

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-361068 (JP, A) JP-A-3-288677 (JP, A) JP-A 2-112445 (JP, U) JP-A-62-1 107950 (JP, U) Hira 3-42653 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 11/02

Claims (1)

(57) [Claims] 1. A printer for transporting a sheet between a print head and a platen disposed to face the print head and printing the sheet by the print head, wherein the platen has a long exposure length. Platen member having a slanted surface inclined to the back side toward the edge at an edge portion extending in the longitudinal direction of the surface to be formed, and exposing and holding the long surface of the long platen member by insert molding And a platen frame molded from a synthetic resin material.