JPH04140166A - Line thermal printer - Google Patents

Abstract

PURPOSE:To contrive to simplify an assembling process by constituting the title line thermal printer in such manner that a paper sensor is formed as a unit and removably fitted in the frame of the line thermal printer. CONSTITUTION:A paper sensor unit 19 is composed of a circuit card 26 and a pair of supporters 27 and 28. A wiring pattern 29 is formed on the surface of the circuit card 26, while a sensor element 30 is fixed on the rear side of that card 26. The sensor unit 30 is electrically connected with the wiring pattern 29 via through hole. One supporter 27 is mounted at one end of the circuit card 26 and the other supporter 28, at the other end and these supporters 27 and 28 are composed of rectangular parallelepipeds with square cross sections and recesses 31 and 32 are formed on outer side faces, respectively. When this pair of recesses 31 and 32 are respectively engaged with the spherical projections 4 and 25 of recesses 16 formed on a frame 1, the paper sensor unit 19 can be removably fitted in the frame.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a small line thermal printer installed in a desk-top or portable information device, and in particular to a device for detecting whether or not printing paper is being fed. The present invention relates to the structure of a vapor sensor used for.

[Conventional technology]

A conventional compact line thermal printer consists of a line thermal head and a platen roller, which are installed in a molding frame and face each other. The printing paper is held between a line thermal head and a platen roller, and printing is performed line by line, and the platen roller rotates to feed the paper. Generally, small line thermal printers have two different printing paper supply paths. One is called a straight paper feed path or straight bus, and the other is called a curved paper feed path or curl bus. The straight paper feed path feeds printing paper almost linearly from the back side to the front side of the line thermal printer, while the curved paper feed path feeds printing paper from one side of the line thermal printer and wraps it around the platen roller until it is fed to the front side. This will lead to printing paper. Both of these paper feeding paths are selected depending on the arrangement orientation of the line thermal printer or the type of printing paper.

By the way, if you mistakenly perform a printing operation when printing paper is not being fed, the heating element of the line thermal head is in direct contact with the surface of the platen roller, so there is a risk of deterioration or damage to the heating element. be. For this reason, line thermal printers generally include a vapor sensor for detecting printing paper.

[Invention or problem to be solved]

However, in conventional line thermal printers, vapor sensors are installed and fixed with screws in accordance with a preselected paper feeding path.

Therefore, in the installed state, the vapor sensor was able to detect only the printing paper inserted into one of the paper feed paths selected in advance.

Even if there was a later need to switch the paper feeding route, it was not possible to do so because the vapor sensor was fixed. Therefore, even if one of the paper feed paths can be selected at the time of assembly of the line thermal printer, there is an inconvenience in that it is not possible to appropriately switch the paper feed path and perform printing during actual use. Although it is possible to temporarily remove the vapor sensor that is fixed with a screw and reassemble other vapor sensor parts to suit a different paper feeding path, this method is still extremely complicated and inconvenient.

[Means to solve problems]

In view of the above-mentioned problems of the conventional line thermal printer, according to one aspect of the present invention, the vapor sensor is formed into a unit and is detachably fitted into the frame of the line thermal printer.

That is, the vapor sensor unit is fitted in a position close to both the linear paper feed path and the curved paper feed path, and is designed to detect printing paper passing through the linear paper feed path and the curved paper feed path. The paper sensor unit has a single sensor element on one surface thereof.

The holding body having a square cross section allows the paper sensor unit to be attached to the frame or inserted into the frame, depending on the paper feeding path to be used.

According to another aspect of the invention, the paper sensor unit comprises two sensor elements disposed on one surface facing the straight paper feed path and on the other surface facing the curved paper feed path. There is.

[Action of the invention]

According to the present invention, the vapor sensor is unitized,
It is fitted in a position where printing paper passing through any paper feeding path can be detected. Therefore, even if two different paper feeding paths are frequently switched, it can be easily handled. For example, when switching the paper feeding route, first the paper sensor unit is taken out from the frame, and then the paper sensor unit is fitted into the frame again while adjusting its posture to the switched paper feeding route.

Alternatively, two sensor elements may be attached in advance to different surfaces of the paper sensor unit so as to face the linear paper feed path and the curved paper feed path, respectively. In this way, the paper feeding route can be changed at any time. Additionally, even if the paper sensor unit breaks down, it can be easily maintained and replaced.

〔Example〕

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a central sectional view of a small line thermal printer taken along the paper feeding direction. As shown in the figure, the line thermal printer is assembled using a frame 1 as a base. The frame 1 consists of one side wall portion 2 and the other frame side wall portion (
(not shown). The pair of frame side wall portions are connected to each other by a connecting portion 3 represented by hatching. This frame 1 has a line thermal head 4
is installed. The line thermal head 4 is a heating element 5
and a head support body 6 that supports this. The lower part of the head support 6 is rotatably supported by a rotation shaft 7. Further, a head up roller 9 is rotatably attached to the upper part of the head support 6 via a head up shaft 8. This head-up roller 9 engages with a notch guide portion 10 formed in the side wall portion 2 of the frame. By manually operating a head-up member (not shown), the head-up roller 9 moves along the notch guide section 10 to open and close the line thermal head 4. A platen roller 11 is further mounted on the frame 1. The platen roller 11 is disposed opposite to the line thermal head 4, and has a rotary shaft 1 supported by a notch bearing 12 formed in the side wall 2 of the frame.
It is rotatably held by 3.

Inside the frame 1, two different paper feeding paths are formed for feeding printing paper between the line thermal head 4 and the platen roller 11. Arrow C indicates a curved paper feeding path or curl path, in which the printing paper is guided along a guide surface 14 formed inside the frame 1 and is discharged while being wound around the platen roller 11. The discharge route is indicated by an arrow. On the other hand, arrow S indicates a straight paper feed path or straight bus, in which the printing paper passes through the surface of the platen roller 11 in a substantially straight line through an opening 15 formed in the frame 1 and is guided to a discharge path.

These two paper feeding paths are switched at any time depending on the arrangement orientation of the line thermal printer and the type of printing paper.

Inside the frame 1, a recess 16 is formed at a position close to both the linear paper feed path C and the curved paper feed path S. A window 17 is formed in the side wall of the recess 16 so as to face the linear sheet feeding path S.

A window 18 is also formed in the ceiling of the recess 16 so as to face the curved sheet feeding path C. A paper sensor unit 19 is removably incorporated into the recess 16 . This vapor sensor unit 19 can detect printing paper passing through the straight paper feed path S through the window 17, and
The printing paper passing through the curved paper feeding path C can be detected through the curved paper feeding path C.

FIG. 2 is a schematic plan view of the line thermal printer shown in FIG. 1. As shown in the figure, the platen roller 11 is supported at both ends by a pair of frame side walls 2 and 20 via a rotating shaft 13. A head-up member 21 is attached to one end of the rotating shaft 13, and a driving gear 22 for rotating the platen roller 11 is attached to the other end of the rotating shaft 13.

A line thermal head 4 faces the platen roller 11.
is installed. The line thermal head 4 has a head support 6 made of, for example, an extruded product, and is supported at both ends by a pair of frame side walls 2 and 20 via a rotation shaft 7 passing through the head support 6. ing. Furthermore, a head up roller 9 is attached to the head support 6 via a head up shaft 8. As described above, by manually operating the head up member 21, the head up roller 9 is moved up and down, and the line thermal head 4 is opened and closed.

A guide surface 14 is formed on the lower surface of the frame 1, and defines the curved paper feeding path C as described above. On the other hand, there is a gap between the platen roller 11 and the line thermal head 4, which defines a discharge path. As is clear from the figure, the printing paper inserted from the curved paper feed path C is ejected through the ejection path while being wound around the platen roller 11.

FIG. 3 is a back or bottom view of the line thermal printer shown in FIG. 1. As shown in the figure, a slit-shaped opening 15 is formed in the bottom surface of the frame l, and defines a linear paper feeding path S. A recess 16 is further formed on the bottom surface of the frame 1 into which a vapor sensor unit is fitted. However, FIG. 3 shows the state with the vapor sensor unit removed. Spherical projections 24 and 25 are formed at both longitudinal ends of the recess 16 to position and fix the vapor sensor unit. A window I7 communicating with the linear sheet feeding path S is formed in the side wall of the recess 16. Further, another window section 18 is formed on the ceiling surface of the recessed section 1B and communicates with the curved sheet feeding path C.

By arranging the pair of windows 17 and 18 to face different paper feed paths in this way, it is possible to always detect the presence or absence of printing paper even if the paper feed path to be used is switched.

In addition, as shown in the figure, the line thermal head 4 has a rotating shaft 7.
The flat cable 23 for supplying power to the heating element 5 is connected to the heating element 5.

Next, a specific configuration example of the vapor sensor unit will be described with reference to FIGS. 4(A) and 4(B).

In this example, a case is shown in which the mounting posture of the vapor sensor unit with respect to the frame can be selected according to the paper feeding path to be used. FIG. 4(A) is a front view of the vapor sensor unit 19. Vapor sensor unit 19
is composed of a circuit board 26 and a pair of holders 27 and 28. There is a wiring button 29 on the surface of the circuit board 26.
is formed, and a sensor element 30 is fixed to the back side of the circuit board 26. The sensor unit 30 is electrically connected to the wiring pattern 29 via a through hole. One holder 27 is attached to one end of the circuit board 26, and the other holder 28 is attached to the other end. The holders 27 and 28 are rectangular parallelepipeds with a square cross section, and have recesses 31 and 32 formed on their outer surfaces, respectively. By engaging the pair of recesses 31 and 32 with the spherical protrusions 24 and 25 of the recess 16 formed in the frame 1, respectively, the vapor sensor unit 19 can be removably fitted into the frame. If the vapor sensor unit 19 is positioned and fitted so that the sensor element 30 is aligned with the window 18, printing paper passing through the curved paper feeding path C can be detected.

FIG. 4(B) is a plan view of the vapor sensor unit 19. As shown, the sensor element 30 mounted on the circuit board 26 is composed of a photointerrupter.

The photointerrupter has a light emitting section 3 consisting of a light emitting diode.
3 and a light receiving section 34 consisting of a photodiode, which detects the presence or absence of light reflected by the printing paper. By fitting the vapor sensor unit 19 into the frame recess 16 so that the light emitting part and the light receiving part are aligned with the window part 17 shown in FIG. 3, printing paper passing through the linear paper feed path S can be detected. can. Since the pair of holders 27 and 28 have a square cross-sectional shape, they can be successfully installed in the frame recess even if the fitting posture is changed by 90 degrees.

Finally, another specific example of the vapor sensor unit will be described with reference to FIG. In this example, the vapor sensor unit has two sensor elements disposed on one surface facing the linear sheet feeding path and on the other surface facing the curved sheet feeding path. Therefore, it is possible to always detect printed paper passing through any paper feeding path, and there is no need to change the fitting posture of the vapor sensor unit in response to switching the paper feeding path. As shown in the figure, the vapor sensor unit 19 is a rectangular parallelepiped molded product 3 having a square cross section.
Consists of 5. A pair of recesses are formed at both ends of the molded product 35 in the longitudinal direction. In FIG. 5, one of the recesses 38
only is shown. One sensor element 37 is embedded in one surface of the rectangular parallelepiped molded product 35, and another sensor element 36 is embedded in the other surface orthogonal thereto. The rectangular parallelepiped molded product 35 having such a configuration is placed in the recess 16 of the frame.
Assembling can be carried out extremely easily by fitting the parts into the parts.

At this time, one sensor element 36 is aligned with the window 17,
The other sensor element 37 may be assembled so as to be aligned with the remaining window portion 18. Furthermore, if the sensor element becomes deteriorated or damaged, it can be easily replaced or maintained.

〔Effect of the invention〕

As explained above, according to the present invention, the paper sensor for detecting printing paper is made into a unit and is configured to be detachably fitted into the frame of a line thermal printer, which has the effect of simplifying the assembly process. be. Furthermore, by selecting the insertion position of the paper sensor unit, it is possible to easily respond to switching of the paper feeding path. Furthermore, by fitting the vapor sensor unit in a position close to both the straight paper feed path and the curved paper feed path, there is an effect that printing paper passing through either paper feed path can be constantly detected.

[Brief explanation of the drawing]

The first tooth is a central sectional view of the line thermal printer cut along the paper feeding direction, Fig. 2 is a schematic plan view of the line thermal printer, Fig. 3 is a schematic bottom view of the line thermal printer, and Fig. 4 4(A) is a schematic front view of the vapor sensor unit, FIG. 4(B) is a schematic plan view of the vapor sensor unit, and FIG. 5 is a schematic perspective view showing another embodiment of the vapor sensor unit. be. DESCRIPTION OF SYMBOLS 1...Frame 2...Frame side wall part 3...Connecting part 4...Line thermal head 5...Heating element 6...Head support body 7
...Rotation axis 8...Head up axis 9
...Head up roller 11...Platen roller 13...Rotating shaft 14-=Guide surface 15.
...Opening 16...Concave part 17...Window part 18...Window part 19...Vapor sensor unit 2B...Circuit board 27...Holder 28
...Holding body 30...Sensor element ratio
Applicant Agent: Seiko Electronic Industries Co., Ltd.

Claims (1)

[Claims] 1. A line thermal head and a platen roller mounted on a frame to face each other, and a linear paper feed formed in the frame to feed printing paper between the line thermal head and the platen roller. In a line thermal printer equipped with both a straight paper feed path and a curved paper feed path, the frame is removably fitted in a position close to both the straight paper feed path and the curved paper feed path, and A paper sensor unit is provided for detecting printing paper passing through a curved paper feed path, and the paper sensor unit has a sensor element on one surface thereof and is used by a holder having a square cross section. A line thermal printer characterized in that the mounting position of the paper sensor unit relative to the frame can be selected according to the paper feeding path. 2. A line thermal head and a platen roller mounted on the frame to face each other, and a straight paper feed path and a curved paper feed path formed in the frame to feed printing paper between the line thermal head and the platen roller. In a line thermal printer equipped with both the linear paper feed path and the curved paper feed path, it is removably fitted in the frame at a position close to both the straight paper feed path and the curved paper feed path, and the The paper sensor unit includes two paper sensor units arranged on one surface facing the linear paper feeding path and the other surface facing the curved paper feeding path. A line thermal printer characterized by having a sensor element.