JPS6236250A - Paper sheet insertion detecting mechanism for thermal recording device - Google Patents

Abstract

PURPOSE:To correctly detect the existence of a business sheet inserted into between a platen and a thermal head by detecting said existence by two electric sensors installed in separation in the business-sheet feeding direction at the both edges of a business-sheet insertion part. CONSTITUTION:A business sheet 14 is inserted into between a platen 11 and a thermal head 12 from a business-sheet insertion part 13. The sensors 10a and 10b for detecting the existence of the business sheet are installed at the position corresponding to the edge parts of the width of the business sheet on the both sides of the passage for the business sheet 14. In order to prevent the contamination with ink for the sensors 10a and 10b, the length of the platen 11 is made narrower than the width of the business sheet, and the width of an ink sheet 16 is made narrower than the length of the platen 11. The sensors 10a and 10b are constituted of movable electrodes 18 and 19 having two electric contacts 18a and 19a separated in the paper-sheet feeding direction and a common electrode 20, and the business sheet 14 passes through therebetween, and the contact points 18a and 19a are opened and closed. Therefore, the existence of the business sheet 14 and the propriety of the attitude of the business sheet can be certainly detected.

Description

[Detailed Description of the Invention] Ritsuka Kanagawa This invention is a thermal recording device such as a thermal printer, copier, or facsimile that records by inserting a sheet between a platen and a thermal head. The present invention relates to a paper insertion detection mechanism.

Long rice mouse! Conventionally, this type of paper insertion detection mechanism was developed in the 1960s.
The one disclosed in Japanese Patent No. 9656 is known.

In a thermal printer, a conductive surface is formed at one end of the outer peripheral surface of the plastic handle, and a detection resistor is provided on the surface of the thermal head to be electrically connected to the conductive surface. When no paper is inserted between them, they are electrically conductive, and when paper is inserted, they are electrically conductive.

However, this method had the following drawbacks.

■ It cannot be detected in transfer type printers where an ink sheet is inserted between the platen and the thermal head in addition to the paper.

■ Detection is not possible unless the platen and thermal head are crimped.

■ Paper feed travel in which the leading edge of the paper is inserted with a bend relative to the axis of the platen cannot be detected.

Purpose The purpose of the present invention is to enable such detection, which was previously impossible.

Configuration This invention provides a sensor that detects the presence or absence of paper insertion as an electrical signal between a platen (11) and a thermal head (12).
A plurality of sheets are arranged at each end of the sheet inserting section (13) between the sheet inserting section (13) and the sheet (14) at a distance from each other in the feeding direction of the sheet (14). Hereinafter, the embodiment will be described in detail with reference to the drawings.

3 and 4 are schematic diagrams showing the layout of the paper insertion detection mechanism according to the present invention. This paper insertion detection mechanism is composed of a pair of left and right detection sections (10a) and (10b). 10a) and (iob) are platen (11
) and the thermal head (12).
), in this example, they are disposed outside the left and right ends of the platen (11).

The paper (14) is guided by the insertion guide (15) and inserted into the paper insertion section (13), and the ink sheet (14) is inserted into the paper insertion section (13).
6) is inserted through the paper insertion section (13) and wound up. The width of the paper (14) is larger than the length of the platen (11), and the paper (14) is attached to the left and right detection units (10a) and (10b).
), but the width of the ink sheet (16) is smaller than the length of the platen (11), and the width of the ink sheet (16) is smaller than the length of the platen (11).
6) is designed so that neither of the left and right detection sections (10a) and (10b) overlap.

As shown in FIG. 1, each detection unit (10a) and (10b) has two movable electrodes, a first and a second, which are conductive rotating pieces that rotate around a common fulcrum (17). (18)・(19)
and a common fixed electrode (20) which is a conductive plate material, and the movable electrodes (18) and (19) each have a spring (21).
), the protrusions (18a) and (19a)
is pressed against the common fixed electrode (20). The second movable electrode (19) is longer than the first movable electrode (18), and the protrusions (18a) and (19a) of both movable electrodes (18) and (19) are longer than the first movable electrode (18).
) are in pressure contact with the common fixed electrode (20) at a predetermined interval in the feeding direction of the paper (14).

In FIG. 2, when a paper (14) is inserted into the paper insertion section (13), the first movable electrode (18) is pushed up by the paper (14) and separated from the common fixed electrode (20). It becomes electrically non-conductive.

When the paper (14) is further fed, the second movable electrode (1
9) is also pushed up and becomes electrically disconnected from the common fixed electrode (20).

Therefore, the first movable electrode (18) and the common fixed electrode (20) constitute a first sensor as shown in the equivalent circuit shown in FIG. (20) similarly constitutes the second sensor,
These are connected to a detection and determination circuit (22).

Therefore, the first sensor of the left detection section (10a) is
a), the second sensor (Ba), the right detection part (lob
), the first sensor (Ab) and the second sensor (Bb)
and a movable electrode (18) or (19) in each sensor.
) is electrically conductive with the common fixed electrode (20), and the output signal when it is electrically non-conductive is "it L". For example, the paper ( 14) is determined. That is, when the paper (14) is inserted into the paper insertion section (13), the detection determination circuit (22) detects that the first sensors (Aa) and (Ab) are in the position L 31 as shown in FIG. , second
Only when the logic of 11 HD is established between the sensors (Ba) and (ab) of It makes a judgment and outputs a judgment signal of 1'L II.

The determination signal is input to a system controller (not shown).

Next, FIGS. 7 and 8 show other embodiments. In this example, a light emitting element (23) and a light receiving element (23) are used as sensors.
A reflective photosensor (25) in combination with
There are two sets buried on the left and right sides. This electric circuit is shown in FIG.

In this case, the length of the platen (11) may be longer than the width of the paper (14).

Note that at least two sensors are required for each of the left and right ends of the paper insertion section (13), but there may be three or more sensors.

effect This invention has the following effects.

(2) Even in a transfer type printer where an ink sheet is inserted between the platen and the thermal head in addition to the paper, it is possible to detect whether or not the paper has been inserted correctly.

■ The presence or absence of paper insertion can be detected even if the platen and thermal head are not pressed together.

■ It is also possible to detect paper feeding problems such as the leading edge of paper being inserted crooked with respect to the axis of the platen.

[Brief explanation of drawings]

FIG. 1 is a side view showing essential parts of an embodiment of the paper insertion detection mechanism of the present invention, FIG. 2 is a side view showing its operating state, and FIGS. 3 and 4 are schematic perspective views showing their arrangement relationship. FIG. 5 is an equivalent circuit diagram of the sensor, and FIG. 6 is an explanatory diagram showing determination logic. Further, FIGS. 7 to 9 show other embodiments, in which FIG. 7 is a front view, FIG. 8 is a side view, and FIG. 9 is an electric circuit diagram. (11)・・・・・・・・・・・・・・・・・・・・・
・・・Platen (12)・・・・・・・・・・・・・・・
...Thermal head (12b)...
・・・・・・・・・・・・・・・・・・Thermal head board (13)・・・・・・・・・・・・・・・・・・
・・・・・・Paper insertion section (14)・・・・・・・・・
・・・・・・・・・・・・・・・Paper (Aa)・(Ab
) ・(Ba) ・(Bb)-Sensor (18)・(19
)・・・・・・・・・・・・Movable electrode (20)・
・・・・・・・・・・・・・・・・・・・・・ Common fixed electrode (25)・・・・・・・・・・・・・・・・・・
・・・・・・Photo sensor Figure 1 Figure 2, 20 18a 19a 41!1 Figure 7 Figure 8 -

Claims (1)

[Claims] 1. In a thermal recording device that inserts paper into a paper insertion section between a platen and a thermal head, sensors that detect the presence or absence of paper insertion as an electrical signal are installed at both ends of the paper insertion section. A paper insertion detection mechanism for a thermal recording device, characterized in that a plurality of paper insertion detection mechanisms are arranged at intervals in a paper feeding direction. 2. A paper insertion detection mechanism for a thermal recording apparatus according to claim 1, wherein the sensor is comprised of a pair of electrodes that become electrically non-conductive when paper is inserted. 3. A paper insertion detection mechanism for a thermal recording apparatus according to claim 1, wherein the sensor is embedded in the substrate of the thermal head. 4. A paper insertion detection device for a thermal recording device according to claim 1, wherein the sensor is a photo sensor.