JPH0557917B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to a paper end detecting portion of a rotatably supported detection lever, and when the paper passes through the paper end detecting portion and the paper end passes through the detecting portion, the restriction by the paper is released. The present invention relates to a paper end detection device in a paper feeding device, in which at least a portion of a detection lever enters a depressed portion and a sensor is actuated by the operation of the detection lever at that time.

BACKGROUND ART It is well known that the paper end detection device of the above type is used in various types of printers or other recording devices. This device is used for the purpose of detecting the edge of a sheet of paper and stopping the feeding of the sheet of paper accordingly.

By the way, in this device, the detection lever is placed in a position close to the above-mentioned depression (for example, in a position where the paper end detection part faces the depression part with the paper in between), and when the paper end passes through the paper end detection part, it is detected. Normally, the lever is used so that its own weight pushes the lever into the depressed part,
When the paper feeding path is changed, the detection lever may be moved to a second position that is raised higher than the above-mentioned position (first position). In the latter case as well, when the paper end passes the paper end detection section, the detection lever rotates under its own weight and plunges into the drop-off section, but in conventional devices of this type, the detection lever occupies the second position. If the paper that is in contact with the paper end detection unit moves in an unexpected manner, which is usually referred to as “abare”, or if a perforation or fold of the paper passes through the paper end detection unit, the paper end detection unit will detect the Even if an external force applied to the lever causes the lever to fall to the opposite side of the depressed part and the paper end reaches the paper end detection part,
The detection lever may not rotate toward the depressed part. If such a situation occurs, the role of the paper end detection device will not be fulfilled, and the purpose of providing this device may be lost.

Purpose An object of the present invention is to provide a paper end detection device that eliminates the above-mentioned conventional drawbacks with a simple configuration.

Configuration The present invention achieves the above object by providing a biasing means for biasing the detection lever toward the depressed portion when the detection lever is in at least the second position.

Examples of the present invention will be described below with reference to the drawings,
In addition, the above-mentioned drawbacks of the conventional technology will be clarified with reference to the drawings.

The drawings show a specific example in which the present invention is applied to a paper feeding device of a printer.

In FIGS. 1 and 2, 1 is a printer main body, 13 is a cover thereof, and a platen 8 is rotatably supported on the main body 1. 2 is a page feeder of a paper feeding device, and this feeder 2
has a pair of cases 9, 9a and tractors 3, 3a that are spaced apart from each other, and the tractors 3, 3a are supported by rods 6, 7 that span the cases 9, 9a. The page feeder 2 is supported by the printer body 1 in the state shown in the figure, and is supported by a case 9 or 9.
The rotation of the platen 8 is transmitted to the rod 6 via a transmission device housed in ) or vice versa.

The illustrated paper feeding device is configured to transport long sheets of paper, such as continuous forms, for example, and the paper 10 shown in chain lines in FIG. 1 and in solid lines in FIG.
is normally sent in the direction shown by arrow A in FIG. That is, the paper 10 passes from the right side of the printer main body 1 in FIG. Holes (not shown) formed on both sides of the paper 10 engage with the pins 5 and 5a. Then, the paper 10 is pulled in the direction of arrow A by driving the belts 4, 4a in the direction of arrow B, and the paper 10 exiting the tractors 3, 3a is guided by paper guides 12 attached to cases 9, 9a. It is sent out to the right side of the printer body 1 again.

A printing head (not shown) prints predetermined information on the portion of the paper that has been wrapped around the platen 8 and has reached the printing section, and the portion of the paper that has been engaged with the pins 5, 5a of the tractors 3, 3a is It is held down by paper pressers 31 and 31a which are pivotally connected so that they can be opened and closed,
This prevents the paper 10 from coming off the belts 4, 4a. A paper bail that presses down the paper on the platen, a silencer that absorbs printing noise, etc. are not shown in the figure because they are not directly related to the present invention.

The printing operation on the paper 10 is performed as described above, but the length of the paper 10 is limited, and it is necessary to finish the printing operation on the paper before the trailing edge of the paper reaches the printing section. For this purpose, a paper end detection device 32 according to the present invention is provided in the paper feed device, and the illustrated detection device 32 is connected to a pair of support brackets 1 fixed to a cover 13 of the printer.
7, 17a has a detection lever 20 rotatably supported in the direction of arrow C, and the detection lever 20 has a
Portion 2 extending in a direction substantially perpendicular to the paper feeding direction
0a constitutes the paper end detection section in this example. A lever guide 15 is arranged at a position corresponding to the paper end detection section 20a, and the guide 15 is fixed to a support shaft 16, and each lever guide 1
5 is provided with a depression in the form of a groove 19. Although three lever guides 15 are provided in the illustrated example, the number may be two or any other suitable number.

As explained earlier, when the paper 10 is fed in the direction of the arrow A, the detection lever 20 moves to its paper end detection portion 20a as shown in FIGS. 1 and 2, and as shown by the two-dot chain line in FIG. is lever guide 1
The paper end detection section 20a and the lever guide 1 are located opposite to and close to the groove 19 of
A paper 10 passes between the paper 5 and the paper 10. At this time, paper 10
lightly touches the upper surface of the lever guide 15, and the detection lever 20 rests lightly on it due to its own weight. The position of the detection lever 20 at this time is defined as a first position.

When the trailing edge of the paper 10 passes the paper end detection section 20a, the detection lever 20, whose movement had been restricted by the paper 10 until then, rotates counterclockwise in FIGS. 2 and 3 and detects the paper end. lever 20
At least a portion of the paper end detecting portion 20a in this example falls into the groove 19 as shown by a three-dot chain line (line indicated by three dots and a line) in FIG. At this time, the actuating part 21 provided on the detection lever 20 enters the hole 24 made in the cover 13 (see also FIG. 5), and a sensor fixed inside the cover 13, in this example a micro switch, is activated. 18 actuators are activated. This generates a paper end signal, which stops the feeding of paper 10 and the printing operation of the printer.

By the way, if feeding the paper in the direction of the arrow A mentioned above is referred to as forward feeding, it is often necessary to perform reverse feeding in which the sheet is fed in the opposite direction. Particularly recently, it is not uncommon to create diagrams and the like using a printer using a computer, and there is a strong demand for forward and reverse feeding of paper. In this case, to prevent the paper from sagging during transport,
As shown in FIG. 4, the tractors 3, 3 described earlier
Paper presser 31, 31a on the opposite side of a
3, 33a, the holes in the paper are engaged with the pins 5, 5a of each belt 4, 4a, and the two surfaces of each tractor 3, 3a are used to move the paper 10 in the direction of arrow D.
(reverse direction feeding) or its opposite forward direction A, and predetermined printing is performed on the paper. In this case, the paper portion coming out to the right from the paper presser foot 33, 33a is guided by the second paper guide 11 attached to the case 9, 9a, so that the paper 10
passes through a position away from the lever guide 15 described above. In this case as well, the detection lever 20 is rotated to a second position that is higher than the first position, as shown by the solid line in FIGS. 4 and 3, so that the edge of the paper can be detected. The paper end detection section 20
a lightly touches the right side of the paper, that is, the paper surface on the opposite side from the lever guide 15, and is supported by the paper 10.

When the paper end passes the paper end detection section 20a, the detection lever 20, which has been released from the restraining force by the paper, rotates counterclockwise in FIGS. 3 and 4, and the paper end detection section 20a moves into the groove. 19, the actuating section 21 enters the hole 24 to actuate the switch 18, and paper feeding and printer operation are stopped (three-dot chain line in FIG. 3).

The configuration and operation described above are the same as in the conventional configuration, but in the conventional configuration, the detection lever 20 occupies the second position, and after the trailing edge of the paper passes,
It was constructed so that it could be rotated to a position where the switch could be operated using only a counterclockwise moment due to its own weight. As a result, the paper 10 may be twisted in the direction shown by arrow E in FIG.
Alternatively, when the fold hits the paper end detection part 20a, the detection lever 20 is pushed clockwise in FIG. There is a possibility that it will act in the direction of rotating the clockwise direction. If such a situation arises,
Even when the paper end passes the paper end detection section 20a, the detection lever 20 no longer rotates counterclockwise, that is, to the position where the switch 18 can be activated.
This means that the edge of the paper cannot be detected.

Therefore, in the configuration according to the present invention, especially the third
As clearly shown in the figure and FIG. When in position, the lever 20 is always given a counterclockwise pivoting behavior in FIG. 3 by the spring 22. Furthermore, in the illustrated example, the locking position of the lower end of the spring 22, that is, the position of the pin 23, is located below and slightly to the left of the center of rotation of the detection lever. For this reason, the tension spring 22 functions as a so-called toggle spring, and the position of the detection lever 20 shown by the dashed line in FIGS. 3 and 5 is the dead center, and when the lever 20 is located to the left of this position. In this case, the lever 20 is urged counterclockwise by the spring 22, and conversely, when the lever 20 passes the dead center and reaches the right side, it is urged clockwise. In this case, the third
As can be seen from the figure, the dead center position of the lever 20, indicated by the dashed line, is located to the right of the perpendicular line V.
Therefore, even if the detection lever 20 is kicked from the second position shown by the solid line in FIG.
0 returns to the second position under the action of the spring 22. Normally, the detection lever 20 is not kicked to the dead center position shown by the dashed line in FIG.
0 is always given the tendency to rotate toward the position shown by the three-dot chain line, and the edge of the paper can be reliably detected. When setting the paper, when manually passing the paper 10 to the left side of the paper end detection section 20a, rotate the detection lever 20 to the right from its dead center position as shown by the broken line. When supported against the support bracket 17, the spring 22 gives the detection lever 20 a clockwise rotational tendency, so that the lever 20 is reliably held at the position indicated by the broken line and the paper passing operation is completed. can be easily done.

When the paper 10 is fed in the forward direction shown in FIG. 2, the pin 23 and the detection lever 20 are positioned in the relationship described above, so the length of the spring 22 is shortened and the tensile action of the spring 22 is weakened. , or can be substantially eliminated, so that the paper end detection unit 20a detects the paper 1 due to the spring force during normal paper feeding.
0 is not press-fitted into the groove 19 from above, and the edge of the paper can be detected without any problem.

Note that the illustrated lever guide 15 has a shaft 16 that supports it rotatably, and when feeding the paper without detecting the edge of the paper, the lever guide 1
5 to the position shown in FIG. In this way, even if the end of the paper passes the detection section 20a, the detection lever 20 will not fall any further, and the switch 18 will not operate.

In the above embodiment, the tension spring 22 was used as a means for biasing the detection lever toward the depressed portion.
Other types of springs or means other than springs, such as a weight, may also be used. Further, the depressed portion into which at least a portion of the detection lever enters does not necessarily need to be formed on a special member (lever guide), and may be provided on the cover itself of the printer, for example. It goes without saying that various sensors other than microswitches such as optical sensors can also be used as sensors. The detection lever, depressed part, sensor, etc.
The present invention can be applied without any problem even when the paper edge detection position is changed by being able to move in the left-right direction in the figure.

Further, the present invention can be widely applied to paper feeding devices in various printers such as wire dot printers, thermal printers, thermal transfer printers, and daisy printers, and other recording devices.

Effects According to the present invention, the drawback that the end of the paper cannot be detected due to the external force applied to the detection lever by the paper can be eliminated with a simple configuration.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a printer to which the present invention is applied, showing only the parts related to the present invention, and Figure 2 is a perspective view of the printer to which the present invention is applied.
3 is a partial sectional explanatory view showing the operating state of the detection lever; FIG. 4 is a sectional view similar to FIG. 2 showing a state in which paper is fed in a different form from FIG. Figure 5 shows an enlarged part of Figure 1,
FIG. 6 is a perspective view showing the movement of the detection lever, and a partial sectional view showing the state of the lever guide when paper end detection is not performed. 10...Paper, 20...Detection lever, 20a...
...Paper end detection unit, 32...Paper end detection device.

Claims (1)

[Scope of Claims] 1. A sheet of paper is passed through contact with a paper end detection portion of a rotatably supported detection lever, and when the paper end passes through the detection portion, at least one of the detection levers is released from being restrained by the paper. The sheet enters the depressed portion, and the sensor is actuated by the operation of the detection lever at that time, and the detection lever is moved between a first position closer to the depressed portion and a state at this position, depending on the feeding path of the paper. In a paper end detection device in a paper feed device that is selectively used in a second position in an upright state, when the detection lever is in at least the second position, the lever is directed toward a depressed portion. The detection device is characterized in that it is provided with a biasing means for biasing.