JPH04140175A - Line thermal printer - Google Patents

Abstract

PURPOSE:To simplify a bearing structure, to reduce the number of parts and to reduce manufacturing cost by forming a head support from a standard length molded product or pultrusion product and engaging the same with a head rotary shaft in a revolvable manner through the bearing groove formed along a paper width direction. CONSTITUTION:A line thermal printer is incorporated in a frame 1 composed of a plastic injection molded product. A platen roller 4 is supported at both ends thereof in a rotatable manner by a pair of frame side wall parts 2, 3 and a head support 5 is also supported at both ends thereof in a rotatable manner by a pair of the frame side wall parts 2, 3. This head support 5 is provided in order to support a line thermal head in a state openable and closable with respect to the platen roller 4 and composed of a standard length extrusion molded product or pultrusion product, for example, constituted of aluminum and has a bearing groove 7 formed along a paper width direction. A head rotary shaft 6 is supported at both ends thereof between a pair of the frame side wall parts 2, 3. The head support 5 is engaged with the head rotary shaft 6 in a revolvable manner through the bearing groove 7.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a small line thermal printer housed in various types of desk-top or portable information equipment, and particularly relates to a head support for supporting a line thermal head. Regarding structure.

[Conventional technology]

A conventional small line thermal printer is assembled using a frame having a pair of side walls arranged at a predetermined distance in the paper width direction.

A platen roller is supported at both ends by the pair of frame side walls. A head support is used to support the line thermal head so that it can be opened and closed with respect to the platen roller. This head support body is similarly supported at both ends by a pair of frame side walls.

[Problem to be solved by the invention]

In the conventional line thermal printer described above, the head support is molded by a so-called die-casting method using a mold. However, the die casting method has the problem of high manufacturing costs because it uses an expensive mold. Further, due to the design of the mold, it is difficult to form a bearing portion on the head support itself. Therefore, there are problems in that additional parts are required to pivotally support the head support body on the frame, and the pivotal support structure becomes complicated. Furthermore, for the same reason, there is a problem in that the opening/closing mechanism of the head support or the head-up mechanism must also be complicated.

(Means for Solving the Problems) In order to solve the problems and problems of the conventional techniques described above, in the present invention, the head support is made of an extrusion molded product or a pultrusion molded product of fixed size, and On the other hand, a head rotating ring is supported at both ends between a pair of side walls of the frame.The head support body supports the head through an extruded bearing groove. It is rotatably engaged with the rotation shaft and enables the line thermal head to open and close.

The extruded head support further has a longitudinal groove formed parallel to the bearing groove.

A head-up shaft having a head-up roller attached to one end is rotatably inserted into this longitudinal groove. A head-up member is disposed on one side wall of the frame for directly acting on the head-up roller to open and close the line thermal head.

In addition, a fixing plate is fitted into the frame on the opposite side of the platen roller, facing the head support. An elastic member such as a coil spring is installed between the head support and the fixed plate, and presses the head support against the platen roller.

[Action of the invention]

As mentioned above, in the present invention, the head support is constructed from a fixed-sized extrusion molded product. Extrusion molding is performed by extruding or drawing a metal material such as aluminum through a die having a predetermined cross-sectional shape. Therefore, the head support can be manufactured at a lower cost than the conventional die-casting method. Also, by using extrusion molding,
A bearing groove along the extrusion direction can be easily formed in the head support. The head support body can be directly attached to the head rotation shaft built into the frame through this bearing groove. At the same time, a longitudinal groove can be formed parallel to the bearing groove. A head-up shaft having a head-up roller attached to one end is rotatably inserted into this longitudinal groove. The head support can be opened and closed via this head up roller. Therefore, the assembly structure of the head support body into the frame becomes simple, and the assembly work is also facilitated.

〔Example〕

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic plan view of a line thermal printer according to the present invention. As shown in the figure, the line thermal printer is assembled into a frame 1 made of a plastic injection molded product. This frame 1 has a pair of side walls 2 and 3 arranged at a predetermined interval in the paper width direction.

For example, polycarbonate is used as the plastic material. A platen roller 4 is rotatably supported at both ends by the pair of frame side walls 2 and 3. Further, the head support body 5 is also rotatably supported at both ends by a pair of frame side walls 2 and 3. This head support body 5 is for supporting a line thermal head (not shown) so as to be openable and closable with respect to the platen roller 4. The head support 5 is a fixed-sized extrusion molded or pultruded product, and is made of aluminum, for example.

The head support 5 has a bearing groove 6 formed along the paper width direction.
has. On the other hand, a head rotation shaft 7 is supported at both ends between the pair of frame side walls 2 and 3. The head support 5 is rotatably engaged with a head rotation shaft 7 via a bearing groove 6 thereof. As a result, the line thermal head can be opened and closed relative to the platen roller 4. The head support 5 further has a longitudinal groove 8 parallel to the bearing groove 6.
is formed. This longitudinal groove 8 has a head-up shaft 9.
is rotatably inserted. A head up roller 10 is attached to one end of the head up shaft 9. A head-up member 11 is disposed on one frame side wall portion 2, and acts on the head-up roller IO to open and close the line thermal head.

A fixing plate 12 is fitted into the frame 1 on the opposite side of the platen roller 4, facing the head support 5. An elastic member 13 made of a coil spring or the like is installed between the head support 5 and the fixed plate 12, and presses the head support 5 against the platen roller 4.

FIG. 2 is a central sectional view of the line thermal printer shown in FIG. 1 taken along the paper feeding direction.

As shown in the figure, a connection portion shown by hatching is formed on the inner surface of one frame side wall portion 2, and connects one frame side wall portion 2 and the other frame side wall portion 3 (not shown) to each other. One end of the rotation shaft of the platen roller 4 is engaged with a notch bearing portion 14 formed in the frame side wall portion 2, and is rotatably supported. Similarly, although not shown, the other end of the rotating shaft of the platen roller 4 is also supported by a notch bearing formed in the other frame side wall 3. The head support 5 is arranged opposite to the platen roller 4. As described above, a bearing groove 6 is formed in the lower part of the head support body 5 made of an extrusion molded product, and the head rotation shaft 7 is inserted into this bearing groove 6. With this structure, the head support 5 is rotatable about the head rotation axis 7 and performs opening/closing motion with respect to the platen roller 4. Further, a longitudinal groove 8 is formed in the upper part of the head support body 5, and a head-up shaft 9 is inserted into this longitudinal groove 8.

A head-up roller IO is attached to one end of the head-up shaft 9 as described above. This head-up roller IO is disposed so as to be movable along a notch guide portion 15 formed in the side wall portion 2 of the frame.

By operating a head-up member 11 (not shown) to move the head-up roller 10 along the notch guide portion 15, the head support 5 performs a swinging motion about the head rotation axis 7.

A line thermal head 16 is installed on the front side of the head support 5.
is attached so that it can come into contact with the surface of the platen roller 4. On the other hand, the elastic member 13 is in contact with the back side of the head support 5 as described above, and the head support 5
is pressed against the platen roller 4.

In the embodiment shown in FIGS. 1 and 2, the line thermal printer has two different paper feed paths.

The paper feed path indicated by arrow C is called a curl bus.
The printing paper is fed to a printing section consisting of a line thermal head while being wound around a platen roller 4. Also, the paper feeding path indicated by arrow S is called a straight path.
The printing paper is supplied to the printing section almost linearly. These two paper feeding paths can be selected as appropriate depending on the purpose of the printer and the type of printing paper. The supplied printing paper is taken out via a common discharge path indicated by an arrow.

Next, with reference to FIGS. 3(A) and 3(B), the structure of the head support 5, which is a main part of the present invention, will be explained in detail. Note that FIG. 3(A) shows the cross-sectional structure of the head support, and FIG. 3(B) similarly shows the surface shape of the head support. As shown in the figure, the head support 5 is processed by extrusion molding or pultrusion molding using a die having a predetermined opening shape. In this extrusion molding, pressure is applied to a metal material such as aluminum in a plastic state, and the material is extruded or pulled out from a die. The elongated material extruded in this manner is cut into a fixed size along the paper width direction to obtain a head support 5 as shown in FIG. 3(B). By simply setting the cutting dimensions appropriately, it is possible to correspond to line thermal printers having different paper width dimensions, and the manufacturing cost of parts can be significantly reduced. On the other hand, when manufacturing head supports using the conventional die-casting method, expensive molds have to be designed to suit different paper width dimensions, making it impossible to reduce manufacturing costs. Ta. Further, by using extrusion molding, it is possible to form the bearing groove 6 and the longitudinal groove 8 extremely easily. That is, these grooves 6 and 8 extend along the extrusion direction. When the head support body 5 having such a structure is assembled into a line thermal printer frame, the head rotation shaft can be simply inserted into the bearing groove 6, and the installation structure and installation work are extremely simplified. . Furthermore, assembly can be carried out by simply inserting the head-up shaft into the longitudinal groove 8.

Next, the shape of the fixing plate will be briefly explained with reference to FIGS. 4(A) to 4(C). 4(A) is a front view of the fixing plate, FIG. 4(B) is a plan view of the fixing plate, and FIG. 4(C) is a sectional view of the fixing plate. As shown in the figure, the fixing plate 12 is made of a metal plate obtained by press working. By appropriately designing its shape, it can be fitted directly into the frame as shown in Figure 2. Therefore, there is no need for additional parts such as screws to fix the fixing plate to the frame as in the prior art, and the installation work is simplified. As described above, the elastic member 13 is installed between the fixing plate 12 and the back surface of the head support 5 so as to press the head support 5 against the platen roller 4. As a result, the line thermal head attached to the front surface side of the head support 5 is pressed against the platen roller to enable proper printing operation.

Finally, the operation of the line thermal printer according to the present invention will be briefly explained with reference to FIGS. 5(A) and 5(B). FIG. 5(A) shows the head-up state, with the head support 5
is rotated clockwise as shown by the arrow. In this state, the line thermal head attached to the front side of the head support 5 (shown as a line for simplicity) and the platen roller 4 (not shown) are separated from each other, and the printing paper is inserted and set. . The head up roller lO attached to the upper part of the head support 5 is connected to the head up member 1
It is pushed up by the cam surface 17 of No. 1.

As a result, the head up roller 10
The head support 5 is being rotated clockwise about the head rotation axis 7. At this time, the head up roller lO
Since it is rotatably attached via the head-up shaft 9, it can roll and move along the cam surface 17, allowing a smooth head-up operation. On the contrary,
In the conventional structure, a pin is driven into the die-cast head support, and the head support is opened and closed via this pin. Therefore, this pin is fixed and cannot roll, making it impossible to smoothly open and close the head.

FIG. 5(B) shows a so-called head-down state, in which the line thermal head mounted on the head support 5 and the platen roller are in pressure contact and a printing operation is performed. In this state, the head-up roller 10 is separated from the cam surface 17 of the head-up member 11 and is positioned at the bottom of the notch guide portion 15 by the biasing force of an elastic member (not shown). As a result, the head support 5 is rotated counterclockwise about the head rotation axis 7. At this time, the switch cam 1 interlocks with the cam surface 17 of the head up member 11.
8 comes into contact with the open/close switch 19, indicating that the line thermal printer is ready for printing.

〔Effect of the invention〕

As explained above, according to the present invention, by constructing the head support body from a fixed-sized extrusion molded product, manufacturing costs can be reduced compared to conventional die-cast molded products.

By processing the head support by extrusion molding, a bearing groove can be formed at the same time, which has the effect of simplifying the bearing structure of the head support and reducing the number of parts compared to the conventional method.

Further, according to the present invention, the head-up roller can be rotatably attached to the head support, and by having the head-up cam act on this head-up roller, it is possible to perform a head-up operation more smoothly than in the past. effective.

Furthermore, in order to support and fix the pressing member to the head support body, the fixing plate is directly fitted into the frame, which has the effect of simplifying the assembly work compared to the prior art.

[Brief explanation of drawings]

Figure 1 is a schematic plan view of a line thermal printer, Figure 2 is a schematic plan view of a line thermal printer.
The figure is a central cross-sectional view of the line thermal printer along the paper feeding direction, Figure 3 (A) is a cross-sectional view of the head support incorporated in the line thermal printer, and Figure 3 (B) is a surface view of the head support. , Figure 4 (A) is a front view of the fixing plate incorporated into the line thermal printer, Figure 4 (B)
4(C) is a sectional view of the fixing plate, FIG. 5(A) is a schematic diagram for explaining the operation of the line thermal printer, showing the head-up state, and FIG. FIG. 5(B) is a schematic diagram for explaining the operation of the line thermal printer, and shows the head down state. 1...Frame 3...Frame side wall portion 5...Head support 7...Head rotation shaft 9...Head up shaft lO...Head up roller 11...Head up member 13... ...Elastic member 2...Frame side wall 4...Platen roller 6...Bearing groove 8...Longitudinal groove 12...Fixing plate Applicant: Seiko Electronic Industries Co., Ltd. Agent

Claims (1)

[Claims] 1. A frame having a pair of side walls arranged at a predetermined distance in the paper width direction, a platen roller supported at both ends by the pair of side walls, and a frame that can be opened and closed with respect to the platen roller. In a line thermal printer having a head support for supporting a line thermal head, a head rotation shaft is supported at both ends between the pair of side walls, and the head support has a fixed size. It is made of an extrusion molded product and has a bearing groove formed along the paper width direction, and the head support body is rotatably engaged with the head rotation shaft through the bearing groove, so that the line thermal head can be rotated. A line thermal printer that can be opened and closed. 2. The head support has a longitudinal groove formed parallel to the bearing groove, and a head-up shaft having a head-up roller attached to one end is rotatably inserted into the longitudinal groove. 2. A head-up member according to claim 1, further comprising a head-up member disposed on one side wall of the frame for acting on the head-up roller to open and close the line thermal head. Line thermal printer. 3. A fixing plate fitted into the frame on the opposite side of the platen roller facing the head support, and a fixing plate fitted between the head support and the fixing plate to press the head support against the platen roller. The line thermal printer according to claim 1, further comprising an elastic member.