JPS62211156A - Thermal head positioning device for thermal printer - Google Patents

Abstract

PURPOSE:To maintain a high accuracy of relative position between a thermal head and a platen roller easily and reliably by constructing the thermal printer body with an upper frame and a lower frame and providing a receiving member at a predetermined position of a head supporting member. CONSTITUTION:When the shaft of a platen roller 15 is engaged with an open section 44a of a groove 44, first moving member 33 moves smoothly to engage the shaft completely with the groove 44 of a receiving member 43 thereby the pressure contacting position between a platen roller and a thermal head 8 can be regulated correctly. Particularly, since the receiving member 43 is fixed near a heat generating section 8a of the thermal head 8, the positional relation between the platen roller 15 and the thermal head 8 can be regulated highly accurately. When power is fed to a solenoid 40 to rotate a lever 41, the energizing force of springs 38, 39 functions to move a second moving member 35 to the platen roller side so as to pressure contact the thermal head 8 against the platen roller 15.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a thermal head positioning device for a thermal printer, and more specifically, the present invention relates to a thermal head positioning device for a thermal printer. , relates to a thermal head positioning device for accurately positioning the thermal head relative to the platen roller in a thermal printer configured such that the platen roller is attached to an upper frame and the thermal head is attached to a lower frame.

<Prior art> Traditionally, thermal printers have used a timing belt to transmit rotational force from the main motor drive to the platen drive, and when the thermal head is in pressure contact with the platen roller, the platen roller and the thermal head are Generally, a color image is formed on the paper by moving the paper held between the ink ribbon and the ink ribbon a predetermined distance, and repeating this process for each color.

That is, when the paper and the ink ribbon are moved together, the thermal head is brought into pressure contact with the platen roller, and when only the paper is moved, the thermal head is separated from the platen roller.

In a thermal printer with such a configuration, in order to ensure good thermal transfer, it is necessary to apply a uniform pressing force in the width direction between the platen roller and the thermal head. It is necessary that the heat generating part of the thermal head is accurately pressed in the normal direction of the roller.

In order to accurately press the heat generating part of the thermal head in the normal direction of the platen roller, ■ The relative mounting position of the platen roller and thermal head is adjusted for each thermal printer. The positioning device and the platen roller (t) are installed so that the base of the thermal head can be slid vertically and horizontally.
t) A thermal head positioning device (see Japanese Unexamined Patent Publication No. 49222/1983) has been provided in which the thermal head is supported by a support frame and pressed against a platen roller by a plate spring.

<Problems to be Solved by the Invention> In the thermal head positioning device having the configuration described in (1) above, since each thermal printer has different dimensional errors, assembly errors, etc., it is necessary to deal with these errors. When installing the thermal head and the platen roller, the positions must be adjusted, and the adjustment must be made with high precision, resulting in a problem of reduced work efficiency.

In addition, in the thermal head positioning device having the configuration described in (1) above, a leaf spring is interposed between the thermal head and the chassis to which the thermal head is attached, and the base of the thermal head is slidably supported by the elongated hole. Therefore, the pressure contact state between the thermal head and the platen roller in this direction is 1. However, since the positioning in the direction perpendicular to the above direction is performed by attaching the platen roller to the chassis on the side, dimensional errors and installation errors may occur. If this occurs, there is a problem that accurate positioning between the thermal head and the platen roller cannot be performed.

Also, regarding the correction using the spring mentioned above, the installation of the leaf spring is accurate, and the slide part II! Since the effect of frictional resistance occurs, there is a problem in that there is no guarantee that reliable correction will be performed.

In any of the thermal head positioning devices, it has not been considered from the beginning to use a thermal printer main body consisting of a lower frame and an upper frame that can rotate upward. If this method is applied to a thermal printer having a similar configuration, various errors will be magnified, making it extremely difficult to increase the relative positional accuracy between the thermal head and the platen roller.

<Object of the invention> This invention was made in view of the above problems,
A thermal head positioning device for a thermal printer that can easily and reliably maintain high relative positional accuracy between the thermal head and the platen roller in a thermal printer consisting of a lower frame and an upper frame that can rotate upward. The purpose is to provide.

Means for Solving Problems> In order to achieve the above object, the thermal head positioning device of the present invention comprises a thermal printer main body including a lower frame and an upper frame that is rotatable upward, and the lower frame A head support member is mounted to a predetermined position of the upper frame so as to be movable substantially horizontally via a slide means, and a head support member is mounted at a predetermined position of the head support member to engage with the shaft of a platen roller attached to the upper frame. The receiver has a member that fits together and forms a groove with an opening slightly wider than the shaft.

<Function> With the thermal head positioning device configured as above, the upper frame of the thermal printer main body to which the platen roller is attached is rotated downward, and the shaft of the platen roller is engaged with the groove of the member. By continuing the downward rotation, the head support member slides with the binoculars in which the groove and shaft are engaged, and finally, the head support member slides while maintaining an accurate relative position with respect to the platen roller. Stop. Then, by performing thermal transfer while rotating the platen roller in this state, a thermal transfer image can be obtained.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing examples.

I will clarify.

Fig. 5 is a perspective view of a color thermal printer, in which the main body of the printer is composed of an upper frame (1) and a lower frame ('2J), and a paper feed cassette (3 ), a manual feed bypass (4), and an output tray (5).The paper feed cassette (3) is removable in order to change the paper size, etc.

FIG. 4 is a schematic diagram illustrating the internal mechanism of the color thermal printer, in which a paper conveying section (6) is attached to a predetermined position of the upper frame (1), and a paper transport section (6) is attached to a predetermined position of the lower frame (2). Ink ribbon cartridge (7)
), a thermal head (8), and a head positioning device (9) are attached.

The paper transport section (6) is configured to feed paper] 0 (10a) (1
0b), paper feed path (11a) (11b), registration roller (12), paper feed path (13), paper feed path switching plate (14), platen roller (15), pinch roller (16), ejection roller ( 17), reverse feed roller (18), and reverse feed path (1
9).

By adopting the above configuration, by selectively rotationally driving the paper feed roller (10a) or the paper feed roller (10b), the paper feed roller (10a) or the paper feed roller (10b) is selectively driven to rotate from the paper feed cassette (3) or the manual feed bypass (4). The paper (P) is fed and conveyed through the paper feed path (11a) or the paper feed path (11b), and the registration roller (12) is in a stopped state.
By bringing the tip into contact with , the skew feed is corrected.

Thereafter, by rotating the registration roller (12) at a predetermined timing, the paper feed path (13) and the paper feed path switching plate (14) are passed between the platen roller (15) and the thermal head (8). Guide the paper (P), further convey the paper (P) as the platen roller (15) rotates, guide it between the pinch roller (16), and further guide it to the discharge roller (17) by continuing the conveyance. I can do it.

In addition, when moving the paper (P) back by a predetermined distance,
It is only necessary to rotate the platen roller (15) in the opposite direction and rotate the paper feed path switching plate (14) upward.
) passes through the paper feed path switching plate (14) and returns to the reverse feed roller (18).
and is roughly guided to the reverse feed path (19).

By making the driving peripheral speed of the reverse feed roller (18) larger than the driving peripheral speed of the platen roller (15), the paper (P) is prevented from sagging during reverse feeding, and a predetermined amount of This is a sensor that outputs a permissible slip of the paper (P) when a resistance force greater than the value acts.

The above ink ribbon cartridge (sword is lower case (21)
), the upper case (22), the feed shaft (23) rotatably housed at both ends of the lower case (21), and the winding @
(24) and an ink ribbon (25) whose ends are wound around both shafts (23) and (24), and by transmitting rotational force to the winding shaft (24), the ink ribbon is The ribbon (25) can be wound up. In addition, (26) is the winding auxiliary row, and (27) (
28) and (29) are back tension rollers.

Then, the ink ribbon (25) is
(yellow) area, M (magenta) area, a3 and C(
(cyan) regions are formed sequentially.

The thermal head (8) is entirely covered with a casing made of a material with a high light reflection coefficient, such as aluminum, and the heat generating part is in pressure contact with the platen roller (15). An ink ribbon separation member (30) is attached to the downstream side in the conveyance direction to guide the ink ribbon (25) and the paper (P) and to separate them.

1 to 3 are diagrams showing the head positioning device (9) in detail.

The head positioning device (9) includes the lower frame (2).
On the top surface of the fixing member (31) attached to a predetermined position,
The thrust receiver is acuride (product name) as a component (
32), the first movable member (33) that moves in a horizontal direction is attached, and the Accuride (trade name) (34) is attached to a predetermined position of the first movable member (33) in a substantially vertical direction. A spring (38H39) is attached to urge the second moving member (35) in a predetermined direction, and a spring (38H39) is installed to urge the second moving member (35) in a predetermined direction. A solenoid (40) is installed to release the urging force acting on the solenoid (40).
The lever (41) is bent into a predetermined shape and is rotatably supported at a predetermined position, and applies a tensile force to one end of the lever (41). At the position, in a direction opposite to the tensile force by the solenoid (40), a force greater than the biasing force of the spring (381 (39)) is applied.
A spring (42) is attached that applies a biasing force smaller than the tensile force of the solenoid (40).

Therefore, when the solenoid (40) is turned off, the contact portion (41a) of the lever (41) engages with the lower end edge of the second moving member (35), and the spring (3B) (
39) can be prevented from acting at all.

Further, a shaft (3) is attached to a predetermined position of the second moving member (35).
6) so that it can rotate in the width direction (direction parallel to the axis of the platen roller (15)).
37), and the receiver, which has a groove (44) at a predetermined position that can be engaged with the shaft of the platen roller (15), clamps the member (43). The groove (44) formed in the member (43) of the receiver has a smooth shape that gradually expands upward, that is, its opening (44a) is slightly wider than the axis of the platen roller (15). It is formed into a shape.

By adopting the above configuration, the upper frame (1) is rotated downward and the shaft of the platen roller (15) is engaged with the opening (44a) of the groove (44). Since the first moving member (33) moves smoothly, the shaft of the platen roller (15) is completely engaged with the retainer (44) of the member (43), and the platen roller (15) and the thermal head The pressure contact position with (8) can be accurately regulated.

In particular, the receiving member (43) is installed near the heat generating part (8a) of the thermal head (8), and the formation position of the i-shaped (44) is determined by the position of the receiving member (43). I am using a thermal head (8
) and the receiver are located very close to the member (43), so it is possible to regulate the positional relationship between the platen roller (15) and the thermal head (8) with high precision.

Also, the lever (4) is connected to the solenoid (40).
1) is rotated against the urging force of the spring (42), the second moving member (35) is moved toward the platen roller by applying the urging force of the spring (381 (39)). The thermal head (8) can be brought into pressure contact with the platen roller (15).

In this state, the pressing force of the thermal head (8) against the platen roller (15) is set by the elasticity of the spring (38H39), and the pressing force in the width direction is set by the thermal head mounting by the shaft (36). Since the rotation of the member (37) results in a uniformly set state, by energizing the thermal head (8), thermal transfer from the ink ribbon (25) can be performed satisfactorily.

Furthermore, when the power supply to the solenoid (40) is cut off, the lever (41) is rotated by the biasing force of the spring (42), so the second moving member (35) is moved between the springs (38) and (39). It can be moved against the biasing force, and the thermal head (8) can be separated from the platen roller ('15).

The present invention is not limited to the above-mentioned embodiments; for example, it is possible to form the iM (44) in a stepped shape that gradually expands upward, and it is also possible to use a leaf spring as the spring. In addition, it is possible to apply it to a thermal printer that thermally transfers only color, to use a slide means other than Accuride, and in other ways, without changing the gist of the invention. Setting S
It is possible to make one change.

<Effects of the Invention> As described above, the present invention provides a thermal printer with a main body consisting of a lower frame and an upper frame that can rotate upward, in which the thermal head and platen roller can be reliably connected by simply rotating the upper frame downward. This has the unique effect of being able to accurately maintain the relative position with respect to the

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of the thermal head positioning device, Fig. 2 is a partially cutaway perspective view, Fig. 3 is a schematic diagram showing the operating state, and Fig. 4 shows the internal mechanism of the color thermal printer. FIG. 5 is an external perspective view. (8) Thermal head, (9) Head positioning device, (15) Platen roller, (25)
... ink ribbon, (33) ... first moving member,

Claims (1)

[Claims] 1. Controls rotational force transmission to the platen roller By doing so, the platen roller and Insert the paper sandwiched between the multihead and the Move it forward a predetermined distance with the clip ribbon, and use it. Thermal printer that forms images on paper , place the thermal printer body on the bottom cover. frame, and upper frame that can be rotated upwards consists of a frame and a fixed position on the lower frame. Almost horizontally movable via sliding means has a head support member attached to and the location of the head support member. In place, the plate attached to the upper frame Engages with the shaft of the Latin roller, and the opening is aligned with the shaft. A receiver with a slightly wider groove. A service characterized by having a retaining member. -Thermal head in thermal printer Positioning device.