JPH0142070Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a roll paper detection device that detects the presence or absence of roll paper and the end thereof using a reflective photoelectric sensor.

BACKGROUND ART Conventionally, as a method for detecting the presence or absence of a roll paper and the end thereof, a method using a reflective photoelectric sensor and an end mark attached to the end of the roll paper is known. In this method, light is emitted from a photoelectric sensor toward the paper surface, and when this surface-reflected light is received by the photoelectric sensor again, the termination is determined by the magnitude of the received light amount due to the difference in reflectance between the end mark and the white background. In addition, the absence of paper is detected when the light emitted from the photoelectric sensor is not received by the photoelectric sensor again.

However, when using the above method to detect transparent paper that easily transmits light, such as the second original paper, the incident light is transmitted in areas other than the end mark, and the amount of reflected light is extremely low. Since the difference in the amount of reflected light between the end mark and the end mark is small, it is difficult for the end mark to be detected by a photoelectric sensor. Also, since the amount of reflected light is always small, it is detected that there is no paper.

Furthermore, even in the case of plain paper, if the surface of the end mark is glossy, a large amount of light will be reflected from the end mark as well, causing the problem that it will not be detected by the photoelectric sensor.

Purpose The present invention was made in view of the above points, and an object of the present invention is to provide a roll paper detection device that can reliably detect the end and the presence or absence of paper, regardless of whether it is plain paper or transparent paper.

Embodiment FIG. 1 shows a schematic configuration of a paper feeding device equipped with a roll paper detection device according to the present invention, in which 1 is a roll paper, 2 is an upper paper feed roller, and 3
4 is a lower paper feed roller, 4 is an upper paper guide, and 5 is a lower paper guide. Upper and lower paper guide 4,
5 are formed with openings 4a and 5a, respectively, and a reflective photoelectric sensor 6 is provided above the opening 4a so as to be inclined with respect to the paper surface.
A swinging member 7 is swingably provided inside.

As shown in FIG. 2, an end mark M with low reflectance is attached to the end of the roll paper 1 at a position passing directly below the photoelectric sensor 6.

Photoelectric sensor 6 that detects this end mark M
As shown in Fig. 3, it is roughly composed of a light emitting diode LED as a light emitting element and a phototransistor PTR as a light receiving element, each connected to a power supply E via a current limiting resistor _R1 and a load resistor _R2 . When the light emitted from the light emitting diode LED is reflected by the roll paper 1 and enters the phototransistor PTR, the end mark M of the roll paper 1 is detected based on the change in the amount of incident light. . Specifically, in the phototransistor PTR, as the amount of light incident on the light receiving section increases, the collector current Ic increases, but as the amount of incident light decreases, the collector current Ic decreases. This current change is converted into a voltage change by the load resistor R ₂ and output to the output terminals O ₁ and O ₂ . Specifically, when the collector current Ic is large, that is, when the amount of incident light is large, the voltage between the output terminals O ₁ and O ₂ is low;
When the collector current Ic is small, that is, when the amount of incident light is small, the voltage between the output terminals O ₁ and O ₂ is high.
The state of the roll paper 1 is determined by inputting this voltage change to an appropriate determination circuit (not shown). In this embodiment, it is determined that the roll paper 1 is present when the amount of incident light is large and the voltage between the output terminals O ₁ and O ₂ is low, and when the amount of incident light is small and the voltage between the output terminals O ₁ and O ₂ is low. It is configured to determine that there is no roll paper or that there is an end mark M.

As shown in FIG. 2, the photoelectric sensor 6 configured in this manner is provided at an angle with respect to one surface of the roll paper, and the light a emitted from the photoelectric sensor 6 is directed to the surface of the roll paper 1. Of the reflected lights, the diffused reflected light c is received instead of the specular reflected light b.

As shown in FIG. 4, the swinging member 7 has a reflective surface 8 on its upper surface, an L-shaped balancer portion 9 on one end, and a curved surface portion 10 on the other end, and is slightly closer to the curved surface portion 10 than its center of gravity. A support shaft 11 is provided at the support shaft 1.
1 is swingably attached to a bearing 12 provided on the back surface of the lower paper guide 5. The swinging member 7 attached in this manner is tilted and stationary when the roll paper 1 is not attached, and when the roll paper 1 is attached as shown in FIG. The curved surface portion 10 is pressed by the rollers, rotates about the support shaft 11, and remains stationary at an angle such that the reflective surface 8 is approximately parallel to the back surface of the roll paper 1.

In the above configuration, plain paper roll paper 1
5, the light a emitted from the photoelectric sensor 6 is reflected on the surface of the roll paper 1 as specularly reflected light b and diffusely reflected light c. Of these reflected lights, only the diffusely reflected light c, especially that directed toward the photoelectric sensor 6, is received, and this received light level is used as a reference level for detecting the presence of paper.

On the other hand, when the roll paper 1 made of transparent paper is mounted, a part of the light emitted from the photoelectric sensor 6 becomes specularly reflected light b and diffusely reflected light c on the surface of the roll paper 1, as shown in FIG. A part of the reflected light passes through the roll paper 1 and is regularly reflected and diffusely reflected by the reflecting surface 8 of the swinging member 7, and a part of the light is repeatedly reflected internally within the roll paper 1. In this way, in the case of transparent paper, complicated reflection occurs due to the interposition of the reflective surface 8, and as a result, the photoelectric sensor 6
The level of the diffusely reflected light c toward the paper becomes equal to the level of plain paper, and the presence of paper is detected.

When the roll paper 1 approaches the end and the end mark M marked on the roll paper 1 reaches below the photoelectric sensor 6 as shown in FIG. Regardless of the transmitting paper, the diffusely reflected light is absorbed by the end mark, and the amount of diffusely reflected light is very small, and the amount of light received by the photoelectric sensor 6 is also very small. The light reception level at this time is defined as the end level, and when the amount of light reception falls to this level, the end of the roll paper 1 is detected.

In this embodiment, since the photoelectric sensor 6 is provided at an angle with respect to the surface of the roll paper 1, when a low-density end mark 13 is attached to the transparent paper, the photoelectric sensor 6 passes through the end mark 13 and the reflective surface 8 The specularly reflected light reflected by the photoelectric sensor 6 is not received by the photoelectric sensor 6. Further, even if the surface of the end mark 13 is a rough surface or a glossy surface that receives a lot of specularly reflected light, reliable end detection is possible.

On the other hand, if the roll paper 1 is not attached to the paper feeder, the swinging member 7
rotates about the support shaft 11 and stands still with the reflective surface 8 inclined with respect to the upper and lower paper guides 4 and 5. Therefore, at this time, the light emitted from the photoelectric sensor 6 is regularly reflected and slightly diffusely reflected by the reflecting surface 8, but most of these reflected lights are reflected in the opposite direction to the photoelectric sensor 6, and the light emitted from the photoelectric sensor 6 The amount of light received by is extremely small, and it is detected that the roll paper 1 is not attached.

In the above embodiment, the photoelectric sensor 6 was provided to be inclined with respect to the surface of the roll paper, but in order to determine the specific angle of inclination, the present inventor conducted the following experiment. That is, the angle (hereinafter referred to as swing angle) that the photoelectric sensor 6 makes with the vertical direction of the roll paper 1 is changed, and at each angle, the output terminals O ₁ , The output voltage of O ₂ (Figure 3) was measured and the results shown in the graph of Figure 8 were obtained. In the graph, A shows the output voltage at the blank area of the plain paper, B shows the end mark of the plain paper, C shows the blank map of the transparent paper, and D shows the output voltage at the end mark of the transparent paper.

According to this, from about 0 to 10 degrees, the influence of reflected light from the reflective surface 8 is strong on transparent paper, so the voltage difference between the end mark and the white background is small;
Although it is difficult to distinguish between these, at an angle of 25 degrees or more, a voltage difference of 5V or more is obtained between the white background and the end mark for both plain paper and transparent paper, making stable end detection possible. However, when the temperature exceeds 40 degrees, the output voltage of the transparent paper (white background) gradually increases, and the voltage difference with the plain paper end mark becomes smaller. As a result, it was found that stable end detection is possible when the swing angle is between 25 degrees and 45 degrees.

Effects As described above, according to the roll paper detection device according to the present invention, it is possible to detect the end of transparent paper, such as plain paper or second original paper, and it is possible to detect whether the paper is attached to the device or not. It has a simple configuration and excellent effects, such as being able to detect the presence or absence of something.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a schematic configuration of a paper feeding device equipped with a roll paper detection device according to the present invention, and FIG.
The figure is a perspective view showing the end of the roll paper.
The figure is a circuit diagram showing the circuit configuration of the photoelectric sensor, Fig. 4 is a perspective view of the swinging member, Fig. 5 is a conceptual diagram showing the detection state of plain paper, and Fig. 6 is a conceptual diagram showing the detection state of transparent paper. , FIG. 7 is a sectional view showing the paper feeding device in a state where no roll paper is attached, and FIG. 8 is a graph showing changes in output voltage with respect to each swing angle of the light receiving sensor. DESCRIPTION OF SYMBOLS 1... Roll paper, 4... Upper paper guide, 5... Lower paper guide, 6... Photoelectric sensor, 7... Rocking member, 8... Reflective surface, 9... Balancer part, 10... Curved surface part , 11... Support axis.

Claims (1)

[Claims for Utility Model Registration] A roll paper detection device that detects the presence or absence of roll paper with an end mark attached to the end and the end of the roll paper near the paper passing path, on the same side with respect to the paper passing path. A reflective type consisting of a light emitting part and a light receiving part arranged at an angle with respect to the paper passing road surface so that the light receiving part receives the diffused reflection of the light emitted from the light emitting part on the paper passing road surface. a photoelectric sensor; a first sensor disposed substantially on the paper passing path, having a diffusely reflecting surface on its surface, and coming into contact with the back surface of the roll paper and being substantially parallel to the paper passing path when the roll paper is in the paper passing path; position, and when the roll paper is not in the paper passing path, the biasing force causes the roll paper to tilt with respect to the paper passing path with part of it protruding into the paper passing path, and substantially reflect light from the light emitting part of the photoelectric sensor. a swinging plate member that is swingable between a second position in which the photoelectric sensor does not emit light and a swinging plate member that is provided at a position that can receive light from the light emitting section when in the first position; Light is emitted from the
The light diffusely reflected by the surface of the roll paper, the end mark on the roll paper, or the diffuse reflection surface of the swing plate member positioned at the first position by the transparent roll paper is reflected back to the photoelectric sensor. 1. A roll paper detection device that detects the presence or absence of roll paper and the end of the roll paper based on a difference in the amount of light received when light is received by a light receiving section of the roll paper.