JPH0550702A - Printer - Google Patents

Abstract

PURPOSE:To set and adjust the printing surface 43 of a thermal head 42 to the position proper with respect to the center axis of a platen roller 5 after the assembling of a unit. CONSTITUTION:Both end parts of a thermal head 4 are supported on both end plates 3 of a frame 5 through a shaft body 14 and guide groove parts 12 in which the shaft body 14 is fitted so as to be slidable in the tangential direction of a platen roller 52 are provided to both end plates 3 of the frame 5. A position adjusting means 21 is provided for setting the slide position of the thermal head 42 integrally sliding along with the shaft body 14 with respect to the frame 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer using a thermal head.

[0002]

2. Description of the Related Art As a printing apparatus such as a facsimile or a word processor, a thermal head called a line thermal head, which is long in the width direction of a sheet to be printed, is used to eliminate movement of the thermal head in the sheet width direction. ..

In this printing apparatus, a paper such as thermal paper is sandwiched between the printing surface of the thermal head and the platen roller,
The platen roller rotates to feed the paper in the lengthwise direction while printing, and an opening / closing mechanism is provided to open the thermal head and platen roller for attaching and detaching the paper. A spring for closing is also provided.

By the way, in this type of printing apparatus, if the printing surface of the thermal head is misaligned with the central axis of the platen roller, there is a problem in that the printing density varies.

As a structure for preventing the positional deviation between the printing surface of the thermal head and the central axis of the platen roller, for example, as disclosed in Japanese Patent Laid-Open No. 60-105552, a roller of the platen roller is attached to the thermal head. A guide plate having a recess that fits on the shaft is fixed, and with the recess of this guide plate and the roller shaft fitted, the printing surface of the thermal head and the central axis of the platen roller always have a constant relationship. I am trying to.

[0006]

In the conventional printing apparatus described above, the positional relationship between the printing surface of the thermal head and the central axis of the platen roller must be adjusted in advance before the unit is assembled. Further, after the unit is assembled, if there is a positional deviation due to a poor positional relationship adjustment, a variation in assembly accuracy, or the like, it is necessary to replace or adjust the entire unit.

The present invention has been made in view of the above point, and after the unit is assembled, the printing surface of the thermal head can be positioned and adjusted to an appropriate position with respect to the central axis of the platen roller, and the correct positioning can be performed. An object of the present invention is to provide a printing device that can stabilize the printing density by adjustment.

[0008]

According to the present invention, a frame having end plates at both ends, a thermal head provided between the end plates at both ends of the frame, and a frame facing a printing surface of the thermal head. And a platen roller rotatably provided between the end plates of both ends of the thermal head so that the printing surface of the thermal head can come in contact with and separate from the platen roller. In the printing device supported by, the guide plates are provided on both end plates of the frame so that the shafts at both ends of the thermal head are slidably fitted in the tangential direction of the platen roller. Position adjusting means for positioning the slide position of the head with respect to the frame is provided.

[0009]

In the present invention, the shaft is slid along the guide groove portions provided on both end plates of the frame by the position adjusting means,
By moving the thermal head in the tangential direction of the platen roller integrally with the shaft body, the printing surface of the thermal head is positioned and adjusted at an appropriate position with respect to the central axis of the platen roller.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the printing apparatus of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a frame unit, which is an elongated plate-like substrate 2 made of metal, and this substrate 2
It has a frame 5 composed of metal end plates 3 provided at both ends and a metal guide rod 4 connecting the both end plates 3.

The substrate 2 is a frame member formed by extrusion molding of aluminum or the like and cut into a predetermined length.
Mounting grooves 6 are formed in the rear edge portion of the upper surface and in an intermediate portion from the front edge, and support pins 7 are vertically planted on the front side portions of the left and right ends thereof. The lower ends of the coiled springs 8 are fitted to the outer sides of the support pins 7, respectively.

The end plates 3 are formed by press molding and are fixed to the end portions of the substrate 2 by screws 9 that are screwed into the mounting grooves 6. Circular holes 10 and 11 having narrow insertion openings are formed in the upper edge portion and the front edge portion of the end plate 3. A guide groove 12 is formed horizontally at the rear edge of the end plate 3 and opens at the rear edge. A rod 13 having a screw hole is projectingly provided on the outer end surface of one end plate 3.

Further, shaft bodies 14 are fitted in the guide groove portions 12 of the end plate 3 in a penetrating state. As shown in FIG. 3 (a state viewed from the inside) and FIG. 4, the shaft body 14 has a shaft portion 15 slidably fitted in the guide groove portion 12, and an outer end portion of the shaft portion 15. A head portion 16 having a diameter larger than the groove width of the guide groove portion 12 is formed on the inner side of the guide groove portion 12, and an annular groove 17 is formed on the inner end side of the shaft portion 15. The shaft portion 15 has a screw hole 18 passing through in the radial direction.
Is formed, and a recess is formed at one end of the screw hole 18.
19 are formed.

Position adjusting means 21 for positioning a head unit, which will be described later, is connected to the shaft body 14 through the shaft body 14. The position adjusting means 21 has a screw shaft 22 arranged in the guide groove portion 12 of the end plate 3, and a screw shaft portion 23 having a small diameter is formed at one end of the screw shaft 22. 23 is screwed into the screw hole 18 of the shaft body 14 and the screw shaft
The stepped portion 24 of 22 is pressed against the recessed portion 19 of the shaft body 14 to be fastened and fixed. A screw shaft portion 25 projecting from the rear edge portion of the end plate 3 is formed at the other end of the screw shaft 22, and a washer 26 that abuts on the rear edge portion of the end plate 3 is inserted into the screw shaft portion 25 and two screw shaft portions 25 are inserted. Nuts
27 and 28 are screwed together.

Then, by adjusting the screwing position of the nut 27 with respect to the screw shaft portion 25, the sliding position of the shaft body 14 in the guide groove portion 12 can be adjusted.
It can be held by tightening the nuts 27 and 28 together.

The positioning adjusting means 21 has a biasing means such as a spring (not shown), and the biasing means biases the shaft body 14 or the head unit forward.

A drive unit 31 has a motor 33 mounted on the outer surface side of the support plate 32 and a motor 33 on the inner surface side of the support plate 32.
A gear 34 attached to the drive shaft of the is protruded, and a gear 35 having a large diameter gear portion 35a and a small diameter gear portion 35b meshing with the gear 34 is rotatably supported.

The drive unit 31 is attached to the rod 13 of the one end plate 3 by screwing a screw 36 inserted through the support plate 32.

A head unit 41 has an elongated thermal head 42 called a line thermal head.
In this thermal head 42, a heat dissipation plate 45 made of metal such as aluminum is attached to the lower surface of a circuit board 44 having a printed surface 43 formed on the upper surface, and a metal cover 46 is attached to the upper surface of the circuit board 44. ing.

Mounting brackets 47 are attached to the lower surfaces of both ends of the heat dissipation plate 45 of the thermal head 42 by screws or the like, and bearing pieces 48 are formed at the rear ends of both ends of the thermal head 42 on each mounting bracket 47. This bearing piece 48 has a notched bearing portion 49
Are formed.

The head unit 41 is inserted between the end plates 3 of the frame 5 from above, and the bearing portion of the bearing piece 48 is inserted.
By fitting 49 into the annular groove 17 of the shaft body 14 projecting from the inner surface of the end plate 3, the shaft body 14 is supported so as to be vertically rotatable about the shaft body 14 as a fulcrum. In addition, the head unit 41 has a mounting bracket 47
Is urged upward by a spring 8 that contacts the lower surface of the front part of

Reference numeral 51 denotes a roller unit, which is a platen roller 52.
have. This platen roller 52 is a metal support shaft.
A roller portion 54 made of conductive rubber is formed around 53. A guide lever 55 made of synthetic resin is attached to both ends of the platen roller 52.
Has a bearing hole 56 in which the support shaft 53 is rotatably fitted at the base end portion, and a fitting protrusion 57 is located around the bearing hole 56 and protrudes from the outer end surface of the base end portion. An arc-shaped engaging portion 58 is formed at the tip end portion. A gear 59 is attached to one end of the support shaft 53.

Then, with both guide levers 55 of the roller unit 51 vertical and the notches formed in the fitting projections 57 vertical, they are inserted into the circular holes 10 of each end plate 3 of the frame 5. After that, the guide lever 55 is rotated in the direction of the guide rod 4, and the engaging portion 58 at the tip of the guide lever 55 is fitted into the guide rod 4, so that the guide lever 55 is held at that position. The fitting protrusion 57 is held in the circular hole 10.

Then, in this state, as shown in FIG. 5, the roller portion 54 of the platen roller 52 is moved to the thermal head 42.
The head unit 41 is pushed down against the spring 8 by abutting on the print surface 43 of the platen roller 52, and the roller portion 54 of the platen roller 52 and the print surface 43 of the thermal head 42 are brought into close contact with each other.

The gear 59 of the roller unit 51 meshes with the small-diameter gear portion 35b of the gear 35 of the drive unit 31. Therefore, when the motor 33 of the drive unit 31 is driven in this state, the gear 34 shifts from the gear 34 to the gear. 35 large diameter gear parts 35
a, from the small diameter gear 35b of this gear 35 to the roller unit
The rotation is transmitted to the gear 59 of the 51 and the platen roller 52 is moved to the position shown in FIG.
At, it is designed to rotate counterclockwise.

Reference numeral 61 is a rod unit having a metal opening / closing rod 62, and rivets are provided near both ends of the opening / closing rod 62.
63 have been planted. Attaching / detaching levers 64 are attached to both ends of the opening / closing rod 62, and although not shown, a bearing hole for rotatably supporting the end portion of the opening / closing rod 62 is formed in the attaching / detaching lever 64, A fitting protrusion similar to the fitting protrusion 57 is provided on the outer end surface. Open / close rod
An opening / closing lever 65 is fixed to the other end of 62, and an engaging groove 66 is formed at the base of the opening / closing lever 65.

The rod unit 61, like the roller unit 51, has both the attachment / detachment levers 64 in a horizontal position, and the cutout portions of the fitting protrusions of the attachment / detachment lever 64 in a horizontal position. After inserting into the circular hole 11 of each end plate 3, the attaching / detaching lever 64 is rotated in the direction of the platen roller 52 so that the locking projection 64a on the outer end of the attaching / detaching lever 64 is attached to the end plate 3.
The fitting lever is held in that position and the fitting projection is held in the circular hole 11 by fitting the fitting protrusion into the circular hole 11.

Then, in this state, the engaging groove 66 of the opening / closing lever 65 engages with the engaging pin 67 protruding from the outer end surface of the end plate 3, and the turning range of the opening / closing lever 65 is set. FIG. 5 shows a state in which the open / close lever 65 is rotated backward (rotated counterclockwise in FIG. 5), and the rivet 63 of the open / close rod 62 is shown.
Is located above the mounting bracket 47 of the head unit 41, which allows the rivet 63 of the opening / closing rod 62 to be paired with the mounting bracket 47.
The head unit 41 is lifted by the spring 8 away from 47, and the printing surface 43 of the thermal head 42 of the head unit 41 comes into close contact with the roller portion 54 of the platen roller 52 of the roller unit 51. Also, set the open / close lever 65 to the front side (Fig. 5).
5), the rivet 63 of the opening / closing rod 62 also rotates clockwise in FIG.
The rivet 63 and the head unit 41 to the spring 8
The thermal head of the head unit 41
The printing surface 43 of the roller unit 42 descends and separates from the roller portion 54 of the platen roller 52 of the roller unit 51.

In the printing apparatus having the above-described structure, the opening / closing lever 65 is rotated to lower the thermal head 42 and separate it from the platen roller 52, thereby removing a thermal paper such as thermal paper. It can be inserted between the printing surface 43 of 42 and the roller portion 54 of the platen roller 52. In this state, the opening / closing lever 65 is rotated to raise the thermal head 42 by the spring 8 and urge it toward the platen roller 52, so that the paper P is printed by the thermal head 42 as shown in FIG. It can be sandwiched between the surface 43 and the roller portion 54 of the platen roller 52.

In this state, when the platen roller 52 is rotated counterclockwise in FIG. 5 by the motor 33,
The paper P can be moved, and printing can be performed on the paper P by driving the thermal head 42 in conjunction with the movement of the paper P. The paper P is introduced through the guide rod 4 between the thermal head 42 and the platen roller 52, and then ejected through the open / close rod 62.

In assembling the printing apparatus, the components are assembled to the head unit 41, the roller unit 51 and the rod unit 61 to some extent, and then the spring 8 and the like are attached to the separately assembled frame unit 1. Together with each unit in order to complete easily.

After the assembling, the print density is checked, and if the print density is not light as a whole or the print density is uneven on only one side and the print density is uneven, the positions of both ends of the frame unit 1 are checked. The adjustment means 21 adjusts the positioning of the thermal head 42 with respect to the central axis of the platen roller 52. In FIG. 2, the print surface of the thermal head 42 is shown.
The proper position A between the shaft 43 and the central axis of the platen roller 52 is shown, and the adjustment movement direction F of the head unit 41 is shown.

The adjustment by the respective position adjusting means 21 is performed by loosening the nut 28, rotating the nut 27, and sliding the shaft 14 forward or backward along the guide groove portion 12 of the end plate 3. The corresponding end of the head unit 41 moves forward or backward integrally with the thermal head.
The printing surface 43 of 42 is positioned and adjusted with respect to the central axis of the platen roller 52. If the adjustment state is proper, a predetermined print density can be obtained without variation in the longitudinal direction of the head unit 41. After the adjustment is completed, the nut 28 is tightened together with the nut 27 to keep the adjusted state.

As described above, in the assembled state, the printing surface 43 of the thermal head 42 with respect to the central axis of the platen roller 52.
Therefore, it is not necessary to adjust the position before assembling, and it is possible to significantly loosen the tolerances that are more stringent than necessary in terms of component accuracy. As a result, the product cost can be reduced.

Further, when the thermal head 42 fails, even if the thermal head 42 is replaced, the printing surface 43 of the replaced thermal head 42 can be positioned and adjusted with respect to the central axis of the platen roller 52. , Head unit
41 No need to replace the whole.

In the above-described embodiment, as shown by the chain double-dashed line in FIG. 2, the rear edge of the end plate 3 of the frame 5 is extended to integrally form the support piece 71. The rolled paper P can be rotatably supported, and the rolled paper P can be pulled out and passed over the guide rod 4 and introduced between the thermal head 42 and the platen roller 52.

[0038]

According to the present invention, the shaft body is slid along the guide groove portions provided on both end plates of the frame by the position adjusting means, and the thermal head is integrally moved with the shaft body in the tangential direction of the platen roller. By doing so, the printing surface of the thermal head can be positioned and adjusted at an appropriate position with respect to the central axis of the platen roller, and the positioning and adjustment can be performed even after the unit is assembled, and the printing density can be stabilized.

[Brief description of drawings]

FIG. 1 is a perspective view of a printer according to an embodiment of the present invention, which is exploded for each unit.

FIG. 2 is a plan view of the assembled state.

FIG. 3 is a side view seen from the inner surface side of the position adjusting means portion.

FIG. 4 is a cross-sectional view of the position adjusting means seen from a plane.

FIG. 5 is a cross-sectional view of a part of the printing device.

[Explanation of symbols]

 3 End plate 5 Frame 12 Guide groove portion 14 Shaft body 21 Position adjusting means 42 Thermal head 43 Printing surface 52 Platen roller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B41J 29/02 8804-2C

Claims (1)

[Claims] 1. A frame having end plates at both ends, a thermal head provided between the end plates at both ends of the frame, and a thermal head provided between the end plates at both ends of the frame facing a print surface of the thermal head. A printing device comprising a platen roller provided so that the printing surface of the thermal head can be brought into contact with and separated from the platen roller, and both ends of the thermal head are supported on both end plates of the frame via shafts, Guide frames are provided on both end plates of the frame so that shafts at both ends of the thermal head are slidably fitted in the tangential direction of the platen roller, and the slide position of the thermal head that slides integrally with the shaft is set relative to the frame. A printing apparatus comprising a position adjusting means for positioning the position.