JPH07228417A - Machine glazed paper detecting device - Google Patents

Abstract

PURPOSE:To correctly detect the distinction between the machine glazed paper and a winding core by fixedly providing a photoelectric detector distinctively detecting the machine glazed paper and the winding core wound with it on a moving member kept in pressure contact with the outer periphery of the machine glazed paper. CONSTITUTION:As the machine glazed paper 2 is extracted by a sheet feed roller, the winding diameter of the machine glazed paper 2 on a winding core 1 gradually becomes smaller. A photoelectric detector 5 on a moving member 4 kept in pressure contact with the machine glazed paper 2 receives the reflected light from the machine glazed paper 2, and it receives the reflected light from the winding core 1 when the machine glazed paper 2 on the winding core 1 is used up. The received light quantity is compared with a set threshold value by a control circuit, and whether the reflected light is received from the machine glazed paper 2 or from the winding core 1 is judged. The light other than the reflected light from the machine glazed paper 2 or the winding core 1 is hardly received, thus the distinction between the machine glazed paper 2 and the winding core 1 can be correctly detected by the photoelectric detector 5 having a small luminescence output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll paper detection device used in various printing devices such as printers, copiers and plotters that use roll paper.

[0002]

2. Description of the Related Art Conventionally, in order to detect the presence or absence of roll paper supplied to a printer, the roll paper is wound around a core of a color close to black, and a reflection type optical sensor is provided on the outer circumference of the roll paper. There is a roll paper end detection device in which an optical sensor detects the core to detect the end of the roll paper when all of the roll paper is pulled out.

Further, an optical sensor for detecting the presence / absence of roll paper is provided in the roll paper drawing path, and when the end of the roll paper is separated from the winding core, the optical sensor detects the state where the roll paper has run out. There is a roll paper end detection device adapted to do so.

[0004]

SUMMARY OF THE INVENTION A roll paper end detection device in which a reflection type optical sensor detects a winding core detects a reflection light from a winding core from a state in which a reflection light from a roll paper is detected. To detect changes to the
As the roll diameter of the roll paper decreases, the distance between the optical sensor and the reflection surface (roll paper) increases, and when the roll paper is used up, the light reflected from the core must be received at a considerable distance. . For this reason, in order to obtain reflected light of a certain level or higher, an optical sensor having a light source with a large light emission output must be used. Further, when the distance between the optical sensor and the reflecting surface is increased, the light from the light source and the light from the reflecting surface are diffused, and the light other than the reflected light from the core is detected even though the core is detected. It becomes easy to receive light,
False positives occur. Therefore, the adjustment to adjust the threshold (threshold voltage) that distinguishes whether the amount of light received by the optical sensor is the reflected light from the roll paper or the reflected light from the winding core, only for the purpose of maintaining detection accuracy. It requires means, is complicated in structure, and is expensive.

Further, in a roll paper end detection device in which an optical sensor is arranged in the roll paper pull-out path, the sensor detects the presence of the roll paper when the roll paper sticks to the core and does not separate. However, the roll paper is not fed.

[0006]

The invention according to claim 1 is
A moving member that is biased in one direction and pressed against the outer circumference of the roll paper is movably provided in the vicinity of a supporting unit that supports the roll paper, and the roll paper is provided at a portion of the moving member facing the roll paper. This is a roll paper detection device in which a photoelectric detector for detecting the roll paper around which the roll paper is wound is separately provided.

According to a second aspect of the invention, there is provided a roll paper detecting device according to the first aspect, further comprising a movement amount detecting means for detecting a movement amount of the moving member.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the threshold for distinguishing the amount of light received by the photoelectric detector between the reflected light from the roll paper and the reflected light from the core is the amount of received light. It is a roll paper detection device provided with an adjustment means for making a relative change.

[0009]

According to the first aspect of the invention, since the moving member moves toward the core side as the winding diameter of the roll paper on the core decreases, the photoelectric detector is mounted on the roll paper or the core. The reflected light can be received in the state where they are brought close to each other.

According to the second aspect of the invention, it is possible to detect the change in the remaining amount of the roll paper based on the moving amount of the moving member detected by the moving amount detecting means.

According to the third aspect of the present invention, the detection accuracy for distinguishing the core and the roll paper is further improved by operating the adjusting means according to the difference in the reflectance between the core and the roll paper. be able to.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a cylindrical core, and a roll paper 2 is wound around the core 1. Although not shown, the main body of a printing device such as a printer, a copying machine, or a plotter is provided with a supporting means for rotatably supporting the core 1.
A moving member 4 is fixed to a support shaft 3 which is rotatably supported at a fixed position. The moving member 4 is biased toward the roll paper 2 by a spring (not shown). Further, a reflection type photoelectric detector 5 is fixedly provided at the tip of the moving member 4. Furthermore, the moving amount of the moving member 4,
In other words, the movement amount detecting means 6 for detecting the rotation angle of the support shaft 3.
Is provided. Although not shown, the movement amount detecting means 6 is formed by a slit disc fixed to the end of the support shaft 3 and a transmission type photoelectric detector for detecting the slit formed in the slit disc. There is.

Further, a threshold value (threshold voltage) for distinguishing the amount of light (voltage) received by a light receiving element (not shown) of the photoelectric detector 5 between the reflected light from the roll paper 2 and the reflected light from the winding core 1 is set. Adjustment means (volume) 7 for changing is provided. In this case, there is a relative relationship between the amount of light received by the light receiving element of the photoelectric detector 5 and the threshold value, and the threshold value may be changed with respect to the amount of received light.
May be changed by adjusting means 7 such as a volume.

In such a structure, the roll paper 2 is pulled out by a paper feed roller (not shown). Along with this, the winding diameter of the roll paper 2 on the winding core 1 gradually decreases. On the other hand, the photoelectric detector 5 on the moving member 4 pressed against the roll paper 2 receives the reflected light from the roll paper 2, but the core 1
When the upper roll paper 2 is used up, the reflected light from the core 1 is received. The amount of light received during this period is compared by a control circuit (not shown) with respect to the predetermined threshold value, and it is determined whether the reflected light from the roll paper 2 or the reflected light from the winding core 1.

In this way, the presence or absence of the roll paper 2 on the core 1 is detected. As the roll diameter of the roll paper 2 on the core 1 decreases, the moving member 4 moves to the core 1 side. For,
The reflected light can be received with the photoelectric detector 5 approaching the roll paper 2 or the core 1. This allows
The light from the light emitting element (not shown) of the photoelectric detector 5 can be applied to the roll paper 2 or the core 1 without diffusing, and the reflected light from the roll paper 2 or the core 1 can be diffused. Since it is difficult to receive light other than the reflected light from the roll paper 2 and the core 1, it is possible to receive light without using the photoelectric detector 5 having a small light emission output. Can be accurately detected. This is an effect corresponding to the invention of claim 1.

Further, the moving member 4 moves according to the change in the winding diameter (remaining amount) of the roll paper 2 on the winding core 1, and the moving amount detecting means 6 detects the moving amount, whereby the winding core 1
A change in the winding diameter (remaining amount) of the upper roll paper 2 can also be detected. Moreover, since the moving member 4 that moves to detect the remaining amount of the roll paper 2 is provided with the photoelectric detector 5 that detects the end of the roll paper 2, the function of detecting the end of the roll paper 2 and detecting the remaining amount of the roll paper 2 is provided. Can be made compact and inexpensive. This is an effect corresponding to the invention of claim 2.

Further, even in the conventional case, the necessity of the adjusting means for adjusting the threshold value with respect to the light receiving amount of the optical sensor has been described, but in the conventional case, it is provided only for the purpose of maintaining the detection accuracy. It is a thing. On the other hand, in the present invention, the adjusting means 7 is provided on the assumption that the photoelectric detector 5 is always brought close to the reflecting surface (the roll paper 2 and the core 1). The threshold value for distinguishing the received light amount of the photoelectric detector 5 between the reflected light from the roll paper 2 and the reflected light from the winding core 1 is adjusted by the adjusting means 7 in accordance with the difference in the reflectance with respect to the received light amount. By changing to, it is possible to further improve the detection accuracy. This makes it possible to maintain the detection accuracy within the allowable range even if the core 1 of a color other than black, which has a very low reflectance with respect to the reflectance of the roll paper 2, is used. That is, it is possible to give flexibility to the selection of the color of the winding core 1. This is an effect corresponding to the invention of claim 3.

[0018]

According to the first aspect of the present invention, a moving member that is urged in one direction and pressed against the outer circumference of the roll paper is movably provided, and the roll paper and the roll paper are wound around the moving member. The presence of roll paper on the core is detected because a photoelectric detector that distinguishes between the core and the core is provided, so the presence or absence of roll paper on the core is detected. Since it moves to the core side, it is possible to receive the reflected light in the state where the photoelectric detector is brought close to the roll paper or the core,
This makes it possible to accurately detect the distinction between the roll paper and the core even if a photoelectric detector having a small light emission output is used.

According to a second aspect of the present invention, in the first aspect of the present invention, the moving amount detecting means for detecting the moving amount of the moving member is provided. Therefore, according to the change of the remaining amount of the roll paper on the winding core. By moving the moving member and detecting the moving amount by the moving amount detecting means, it is possible to detect a change in the remaining amount of the roll paper, and further, the moving member moves to detect the remaining amount of the roll paper. Since the member is provided with the photoelectric detector for detecting the end of the roll paper, the functions of the end detection of the roll paper and the remaining amount detection can be made compact and inexpensive.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a threshold value for discriminating the amount of light received by the photoelectric detector into the reflected light from the roll paper and the reflected light from the winding core is the amount of the received light. Since the adjustment means to change relative to is provided,
The threshold value for distinguishing the received light amount of the photoelectric detector between the reflected light from the roll paper and the reflected light from the winding core by the adjusting means according to the difference in reflectance between the core and the roll paper is relative to the received light amount. By changing the color, the core color can be freely selected without impairing the detection accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a side view thereof.

[Explanation of symbols]

 1 core 2 roll paper 4 moving member 5 photoelectric detector 6 moving amount detecting means 7 adjusting means

Claims (3)

[Claims] 1. A moving member, which is urged in one direction and pressed against the outer circumference of the roll paper, is movably provided near a supporting means for supporting the roll paper, and a portion of the moving member facing the roll paper. A roll paper detection device, wherein a photoelectric detector for detecting the roll paper and a core around which the roll paper is wound is provided fixedly on the roll paper. 2. The roll paper detecting device according to claim 1, further comprising a moving amount detecting means for detecting a moving amount of the moving member. 3. An adjusting means is provided for changing a threshold value for distinguishing the received light amount of the photoelectric detector into the reflected light from the roll paper and the reflected light from the core relative to the received light amount. The roll paper detection device according to claim 1 or 2.