JPH0425482A - Thermal printer - Google Patents

Abstract

PURPOSE:To achieve improvement of vibration proof and durability by enabling lateral balancing to be obtained by a method wherein left and right respectively receiving forces are made same centering a carrying direction center line (psi) of a rotary shaft. CONSTITUTION:Since both ends of a shaft 11 of a printing head 3 are fit with no play in long hole 7d and 7e directions freely displacable only in an energizing direction of a compression spring 4, the printing head 3 can be rolling in a carrying direction 9 centering a hole 7c of a first printing head supporting component 5c. However, since displacement is fixed in the carrying direction 9 due to the long holes 7d and 7e, no yawing is generated. Further, since displacement is fixed in a direction vertical to a head heating surface 8 due to the hole 7c, no pitching is generated. Tangential force fP1O received from a platen 1 in printing acts respectively on the printing head supporting components 5c, 5d, 5e, and reaction force fP' is generated to second and third printing head supporting commonness 5d, 5e. Further, energizing force of the compression spring 4 from a head rear surface 8d of the platen 1 in printing makes the first printing head supporting component 5c generate restraint on pitching at a center of the printing head 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a multi-print printer equipped with a printing/printing/setting member.

[Conventional technology]

FIG. 6 is a perspective view of a conventional thermal line printer disclosed in, for example, Japanese Patent Application Publication No. 63-91260.

In the figure, the gear (1) is rotatably supported on the main body (2). (31 is rotatably supported by this main body (2)) Printing ＼, ノ1:, (4) (From the back of the throat (3) to the horizontal printing one degree from the back of the throat (1) Compression spring or biasing member that applies vertical biasing force (5a)
and (5b) are print bed holding members A and B respectively arranged at both ends of this print head holding member A (5a), and a round hole is provided in this print head holding member A (5a). - The force print head holding member B (5b) has a compression spring (
A long elongated hole (7) is provided in the direction of the urging force of 4).

Figures 7 and 8 (printed i respectively / gutter holding member A)
(5a) and B (5b) A partial side sectional view of the vicinity.

, in the figure, (8) is the head heat generating surface, and the blade J
It has a heat generating part (]2) that comes into contact with (1). (9) Arrow [Ejp! JPlate 1 above. Indicates the rotation direction of fll,
aO) is determined by this platen rotation direction (9) during printing,
Head heating surface (8)h・-7°Tangential force received from latte J (1), (llal fits into the above round hole (6), and the main body (
2), the axis of this pin (lla) is parallel to the direction of the heater lie of the heat generating part (2).

(Ilb) is the screw that fits into the elongated hole (7) and is fixed to the main body 12), (11h) is the screw that fits into the long hole (7) and is fixed to the main body 12),
It is coaxial with lla). The arrow in (13) indicates the platen (1
) is the reaction force of the tangential force 00) received from each of the above Bi, (ll
This is the force received from a) and (ITo).

FIG. 9 is a perspective view of a position model of the planar J (1) and the printing/rad heating surface (8). In the figure, (14) is the rotation center formed by the print head holding member A (5a) and the bottle (lla), and (+5b) is the rotation center formed by the print head holding member B (5b) and the pin (Ilb). The irregular rotation center formed, (15a) is the irregular rotation center included in the plane determined by the fixed rotation center (14) and the heat generating part (12), and dL and dR are from the heat generating part (12). Rotation center(
14) and (15a) or 1'1T15b), and the S' plane includes the rotation axis 11 where the head heat generating surface (8) including the heat generating portion (12) is determined by the rotation centers (14) and (15b). The plane and the third plane are the rotation axis I defined by the rotation centers (14) and (15a). A surface containing δ (rotation center at other time (15
This is the distance in the direction perpendicular to the head heat generating surface (8) in a) and (15b).

Figure 10 is a diagram showing the fluctuation of the printing head around each of the three axes, where (a) shows the fluctuation of the printing head around the axis perpendicular to the surface of the gutter, and (b) shows the fluctuation of the printing head of the thermal medium. Printing parallel to the direction of travel ＼ Roller leg indicating wobbling around the central axis of the gutter, (C) (Pitching indicating wobbling around the central axis of rotation of the print head parallel to the rotational axis of the platen, (
d) is the direction of rotation of the platen (1).

Next, the operation will be explained. A printing thermal medium (not shown) is held between Gokko (1) and the print head (3) while being pressurized by a compression spring (4), and the platen (1) is moved in the print feeding direction (9). It is rotated (the drive system is not shown) and printed by being heated by the heat generating part (12) of the print head (3).

Next, the uniformity of pressure applied between the platen (1) and the print head (3) will be explained. Platelet axis (IP)
If there is a spatially twisted relationship such as the rotation center axis (11) of the head heat generating surface (8), then the distance between the heat generating part (12) and the platen (1) at both ends is II! No matter how equal dt and dR are, since the platen (1) is fixed to the main body (2), the platen (11) relative to the print head (3)
This results in uneven printing, resulting in incorrect printing. However, even if it is fixed to the rotation center (14) of the printing/printing holding member A (5al) or the main body (2), printing/\2.1.
The center of rotation of the holding member B (5b) (+5bi is undefined, and the center of rotation is freely displaceable in the direction of 1 dimension of the compression bias 1) without damaging the equality of the distances dL and d□. By moving the center of rotation (15a) included in the third surface by a distance ti of δ, a rotation axis of 1° of the print head is formed, and the contact pressure between the print head (3) and the platen (1) is increased. It has a structure that is automatically set to be uniform.

However, 1. It is necessary that the torsion correction amount δ of and 11 is smaller than the displacement amount of the elongated hole (7).

Next, the force applied to printing/printing (3) will be explained.

Regarding the angle 1 in the direction perpendicular to the head heat generating surface (12) (as shown in Fig. 7, the contact force of the compression spring (4) acts on the negative and horizontal back surfaces (8b) of the print head (3), causing the planar J
The reaction force from (1) acts on the head heat generating surface (8) as a balancing force. Also, in FIG. 8, the same balance of acting forces as described above can be considered. However, in Fig. 7, since it is a long hole (7), the force is not received in the vertical direction, and tMc
This is due to frictional sliding between the hole [7] and pin (11b), but in Figure 8, if a perfect shaft-bearing relationship had been formed between the pin (lla) and the round hole (6), , Naturally, there is a way to receive the force in the vertical direction. The reception of force in the vertical direction between this round hole t6] and the bottle (1]λ) can be thought of as a transfer! , lt, print/\t (3)'s own weight reaction force, prana, tangential force received from (1) + p lo
l and its reaction force 'p f13) are the head heating surface (12
) and the position of action of the compression spring (4) are between the platen (1) and the printing / gutter (3).
Examples include the rotational moment in the pitching direction generated across the entire print head when the print head slides away from the contact position with ), and the reaction force of ). These are considered to disturb the symmetry of the left and right ends of the printing force applied to the gutter (3) when viewed from the central axis in the direction of movement. However, it is possible to obtain good printing performance by making these values less than the allowable limit of the displacement of the elongated hole (7) -2 with the amount of correction δ of the axis l and the axis l.

[Problem to be solved by the invention]

Since conventional thermal printers are configured as described above, the center of gravity of the printing/grid (3) must be placed near the platen (1), and the center of gravity of the printing/grid (14) must be placed near the platen (1). and (15) are subjected to different forces from the left and right bearings, resulting in poor printing performance during vibration, and anomalous left and right sides of the center of rotation H, resulting in short durability and poor printing. .

This invention was made to solve the above-mentioned problems, and since the force received by each side is the same around the center line ψ of the rotating shaft in the conveyance direction, the left and right sides are balanced, and the vibration resistance and durability are improved. The objective is to obtain a thermal printer that has improved performance and can eliminate uneven contact pressure between the left and right sides due to the center of gravity of printing and rad.

[Means to solve the problem]

The thermal printer according to the present invention includes a biasing member that applies a biasing force to the print head in the direction of contact with the platen, and a first print head that rotatably supports the central portion of the print head in the main body.
A second and a third print/rad holding member are provided which support both ends of the print head on the main body so as to be freely displaceable in the same direction as the urging direction.

[Effect]

In this invention, the thermal splitter has a print/gutter rotation axis installed parallel to the platen, and a print head holding member that supports the rotation axis so as to be displaceable in the contact pressure direction, which is disposed at both ends of the print head. Printing / Printing on both ends with the center of the gutter as the center of rotation / The gutter holding member is movable and automatically equalizes the contact pressure between the print head and platen, that is, the equalizing effect works, and the print head surface is Rotation about a vertical axis is prevented and wobbling about a central axis of the printhead parallel to the printhead platen axis is prevented.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) to (4) are exactly the same as the conventional device described above. (1]) is parallel to the platen (1) and the main body (
2), the shaft (5c) is the print head (3)
), the first print head holding member (5d) and (5e) are installed in the center of the main body and are rotatably supported by the main body;
\Second and third printing/\no installed on both ends of \rad (3)~holding members, (7d) and (7e) respectively indicate second and third printing/\rad holding members The elongated hole bearing portion provided in the member has its longitudinal direction aligned with the biasing direction of the compression spring (4), and is movable in the same direction as the biasing direction of the biasing member. (7c) is a bearing portion disposed on the first print head 1 to the holding member, and (8b) is the back surface of the gutter.

Figures 2.3.4 and 2.3.4 respectively. Third. FIG. 3 is a partial side cross-sectional view of the vicinity of each first print head holding member.

In the figure, (8+, +91. (10), (13
) is exactly the same as the conventional device.

Figure 5 shows the platen (1) and the printing/\rad heating surface (8).
FIG. 2 is a perspective view of the position model. In the figure, (12)
is exactly the same as the conventional device. (36) is the rotation axis l
.

and 11 and the head heating surface (8), respectively, at the rotation center (fixed point) common to the S and S' surfaces, and the first
The hole (7c) of the print head holding member (5c) and the elongated hole (7d) of the second and third print head holding members (5d) and (5e), (approximately at the center in the longitudinal direction of 7el) 77 Gloss that penetrates without play (11). (35a) !4On the three planes defined by the center of rotation (36) and the heat generating part (12), there is a, rarely on the S' plane or on the heat generating part. Suppose that it is held down and moves directly to S)
Second printing/gutter holding member (5)
d) The rotation center formed by fitting the elongated hole (7d) with the yoke 1 and (11), (37a) is also included in the third surface and is the elongated hole of the third print head holding member (5e) (7e) and -
The rotation center formed by the fitting of Yahu 1 to (11), (
35b) and (37b) are indefinite points formed by the elongated holes (7d) and (7e) and the layer I-(11),
S' indicating that the rad heating surface (8) is in partial contact with the platen (1)
included in the surface. Here, δR is the vertical distance between the rotation centers (35a) and (35b), δ is the vertical distance between the rotation centers (37a) and (37b), and dR is the rotation center (35a)
and (35h) to the plate and axis IP, and dL is the distance from the rotation center (37a) and (37b) to the bracket axis 1 and the plate.

Next, the operation will be explained. A compression spring (4) connects a print medium (not shown) between the platen (1) and the print head (3).
), the printing head is heated by the heat generating part (I2) of the print head, and one dot row is printed simultaneously.Prana, (1)
When printing while repeating intermittent feeding and heating for each dot line, printing / gutter (3) is yaf) / (11)
Because the two ends of the long hole (7d) can be freely displaced only in the biasing direction of the compression spring (4), they are fitted without any play in the direction of the (7e). Hole (7c) of the first print head holding member (5c) located at
Rolling is possible in the conveying direction (9) around .

However, due to the elongated holes (7d) and (7e), the transport direction (
9) has a structure in which yawing does not occur because the displacement is fixed, and pitch jig does not occur because the displacement is fixed in the direction perpendicular to the hole (7C) and rad heating surface (8). It has become.

Tangential force f p (1) received from platen (1) during printing
01 are the print head holding member (5c), (
5d) and (5e) from the heat generating surface (8) through the printing/rad (3), and a reaction force f,' is applied to the second and third print head holding members (5d) and (5e). (13)
It's bullish.

Also, the biasing force of the compression spring (4) from the back surface (8b) of the planar J (1) during printing acts as a contact force on the planar (1), Parts (5
C) generates a restraining force on the pitch and g at the center of the print head (3), so the entire print head automatically generates a uniform contact pressure, creating a so-called equalizing effect. The rotation axis is 1. Even if the shaft is tilted, this effect will automatically align the platen (1) and heat generating part (12).
) by making the distances dRydL equal to each other and forming five head heat generating surfaces (8) whose inclinations are corrected, which has the effect of uniformly bringing the entire print head into contact with the platen. Moreover, the first mechanical constraint condition for the print head (3) during printing is
Only the rolling of the rotation center (3b) of the head holding portion 0 (5cl) is symmetrical with respect to the center line ψ in the conveying direction.

Although the rotation direction (9) of the platen (1) in FIGS. 2 and 3.4 is counterclockwise, it may also be clockwise.

Further, in the above embodiment, a thermal printer was described, but a thermal transfer printer may also be used and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, during printing of Gori: 7, the printing edge, 1: and 1: support the printing \rad holding member movably in the direction of contact with the planar, respectively.
Since there are marks on both ends of the l- and there is no looseness in the printing medium feeding direction, the rotation axis of the first printing/gutter holding member located in the center of the printing/gutter can be easily adjusted. Low leakage is possible in the conveyance direction as the center, and yawing does not occur, and the first print located in the center of the printing
Due to the rotation axis of the RAD holding member, the displacement is fixed in the direction perpendicular to the head heat generation surface, so a restraining force is generated against pi-notching, so the entire print head automatically and uniformly contacts the print head. Since the inclination of the print head' is automatically corrected by the effect, stable contact pressure can be easily obtained over the entire width of the print head, the device can be made inexpensive, and high accuracy can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view of main parts according to an embodiment of the present invention, and FIGS. 2, 3, and 4 are perspective views of main parts according to an embodiment of the present invention. Partial side sectional views of the first and third printing/gutter holding members, FIG. 5 is a perspective view of a positional model of the platen and print head heat generating surface according to an embodiment of the present invention, and FIG. 6 is a conventional main part. FIGS. 7 and 8 are a partial side sectional view of conventional printing/rad holding members A and B, respectively, and FIGS.
The figure is a perspective view of a conventional printer and a position model of the heat generating surface of the print head, and FIG. 10 is a partial perspective view showing the vibration of the print head around each of the three axes. . In the figure, (1) is the platen, (2) is the main body, (31
(5c) is the first print head holding member, (5d) is the second print head holding member, (5e) is the third print head holding member, (4) is the compression spring (biasing member). In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] a platen rotatably supported by a main body; a print head that moves toward and away from the platen; a biasing member that applies a biasing force to the print head in a direction to bring it into contact with the platen; and a center portion of the print head that rotates relative to the main body. A thermal printer comprising a first print head holding member that freely supports the print head, and second and third print head holding members that support both ends of the print head on the main body so as to be displaceable in the same direction as the biasing direction. printer.