JPH0815957B2 - Printer paper detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing paper detection device for a printer, and more particularly to a printing paper detection device for a printer capable of detecting colored paper and paper that has undergone format printing.

[0002]

2. Description of the Related Art In a printer, it is necessary to detect the leading edge of the printing paper conveyed on the platen in order to know the start timing of the printing operation on the printing paper. Has been.

FIG. 3 shows an example of a printing paper detecting device for a conventional printer, which is, for example, the actual open sho 63-4.
This is disclosed in Japanese Patent Publication No. 9955. As shown in FIG. 3, it is shown that the black platen 35 is provided with a reflection type optical sensor 31 for paper detection and a circuit for detection.

The optical sensor 31 includes a light emitting element 32 and a light receiving element 3.
3 and there is no printing paper on the platen 35,
When the light receiving element 33 does not detect the reflected light and the printing paper is inserted, the light receiving element 33 detects the reflected light based on the printing paper and generates an output, so that the printing paper can be detected in the printer.

FIG. 4 shows another example of a conventional printing paper detecting device for a printer.
No. 2-168044.
As shown in FIG. 4, the optical sensor 41 is provided with a switch 42 that switches and generates a plurality of reference voltages, and a comparison circuit 43 that generates an identification output.

By comparing the output signal V _i of the optical sensor 41 for detecting the reflected light from the printing paper with a plurality of reference voltages V _{1 and} V ₂ which can be switched by the switch 42,
It is possible to generate the output signal V ₀ for detecting the printing paper in accordance with the difference in the paper type (reflectance).

[0007]

In the conventional printing paper detecting apparatus shown in FIG. 3, the printing paper on the platen is reflected by the platen which is usually black and the reflection light from the printing paper which is white or the like. It can be detected based on the difference in light intensity from light, but in the case of black or dark print paper,
It is difficult to detect this reliably.

On the other hand, in the conventional printing paper detecting apparatus shown in FIG. 4, it is possible to obtain an output signal which is obtained by detecting a plurality of kinds of printing papers having different reflectances according to a plurality of kinds of reference voltages. However, the presence / absence cannot be similarly detected for a plurality of types of printing papers having different reflectances.

[0009]

It is an object of the present invention to solve the above-mentioned problems of the prior art, and to provide a printing paper detecting device of a printer for detecting the presence or absence of printing paper using a reflection type optical sensor. The presence / absence of colored paper can also be determined, and the edge of the paper can also be used to determine the presence / absence of paper by performing format printing such as frame printing. It is an object of the present invention to provide a printing paper detection device for a printer that can be used.

[0010]

The present invention is intended to achieve the above-mentioned object by adopting the following configuration.

(1). The present invention relates to a printing paper detection device for a printer which has a reflection type optical sensor and detects the presence or absence of the printing paper by the reflected light from the printing paper. When is inserted,
It has a white light reflector and a first optical sensor that generates a high-level or low-level output depending on the magnitude of the reflectance of the printing paper, and a low-level output when the printing paper is not inserted. Generates high-level or low-level output when print paper is inserted between it and the reflector, depending on the reflectance of the print paper, and when print paper is not inserted, high-level output. A second photosensor, an inverter that inverts the output signal of the first photosensor, and an AND circuit that obtains a logical product of the output signal of the inverter and the output signal of the second photosensor,
It is characterized in that the presence or absence of print paper is determined by the output of the AND circuit.

(2). In the above (1), each of the first and second reflective photosensors includes a light emitting element and a light receiving element that receives reflected light from an object based on light from the light emitting element and generates an output signal. It is characterized by having.

(3). In the above (2), the first and second photosensors are each formed of a reflective photocoupler having a light emitting element and a light receiving element.

[0014]

In the present invention, a reflection type optical sensor is provided, and the presence or absence of the printing paper is detected by the reflected light from the printing paper.

In this case, the first optical sensor 1 has a black reflecting plate 3, and when the printing paper is inserted between the black reflecting plate 3 and the reflecting plate 3, the high light is output according to the reflectance of the printing paper. Which outputs a low-level output or a low-level output when a printing paper is not inserted is used. The second optical sensor 2 has a white reflecting plate 4 and is provided between the reflecting plate 4. When a printing paper is inserted into the printer, a high-level or low-level output is generated according to the reflectance of the printing paper, and a high-level output is generated when the printing paper is not inserted.

Then, the inverter 5 inverts the output signal of the first optical sensor 1, and the AND circuit 6 obtains the logical product of the output signal of the inverter 5 and the output signal of the second optical sensor 2. The output of the AND circuit 6 determines the presence or absence of print paper.

Therefore, according to the present invention, it is possible to similarly detect the presence or absence of a plurality of types of printing paper having different reflectances, and perform format printing such as frame printing on the edge of the paper. It is possible to detect the presence or absence of such a sheet.

In this case, as the first reflection type optical sensor 1, a light emitting element 11 and a light receiving element 12 which receives reflected light from an object based on the light from the light emitting element 11 and generates an output signal. And a light receiving element 22 that receives the reflected light from the object based on the light from the light emitting element 21 and generates an output signal as the second reflective optical sensor 2. Those that have can be used.

Further, as the first and second reflection type optical sensors 1 and 2, reflection type photocouplers having light emitting elements 11 and 21 and light receiving elements 12 and 22 may be used.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 shows a schematic configuration of an embodiment of the present invention. A reflection type optical sensor 1 provided corresponding to a black reflecting plate 3 and a reflection type optical sensor provided corresponding to a white reflecting plate 4. Two sets of paper detection sensors consisting of the mold type optical sensor 2, an inverter 5 for inverting the output signal of the optical sensor 1 using a black reflector, an output signal of this inverter 5 and an output based on the white reflector 4 And an AND circuit 6 for obtaining a logical product with a signal. 2 shows an operation time chart of the embodiment shown in FIG.

In FIG. 1, the reflection type optical sensor 1 has, for example, a light emitting element 11 such as a light emitting diode and a light receiving element 12 such as a phototransistor. It is composed of a reflection type photocoupler which receives the reflected light of and generates an output signal. Similarly, the reflective optical sensor 2 is composed of a reflective photocoupler having a light emitting element 21 such as a light emitting diode and a light receiving element 22 such as a phototransistor.

The reflection type optical sensor 1 emits light by the light emitting element 11 when a current is supplied from the power source Vcc, reflects the light by the black reflecting plate 3 and receives the light by the light receiving element 12, thereby changing the amount of reflected light. The output level of the sensor output 7 is determined accordingly. When the printing paper is not inserted between the reflection type optical sensor 1 and the black reflection plate 3, the amount of reflected light is small and the sensor output 7 becomes low level. Since the sensor output 7 is input to the inverter 5 and inverted, the output of the inverter 5 becomes high level.

Further, the reflection type photosensor 2 emits light by the light emitting element 21 when a current is supplied from the power source Vcc, reflects the light by the white reflecting plate 4 and receives the light by the light receiving element 22, whereby the amount of reflected light is reflected. The output level of the sensor output 8 is determined according to When the printing paper is not inserted between the reflection type optical sensor 2 and the white reflection plate 4, the amount of reflected light is large and the sensor output 8 becomes high level.

The AND circuit 6 performs an AND operation on the output of the inverter 5 and the sensor output 8 to generate an output. The output of the AND circuit 6 becomes high level as shown in FIG. 2 when the printing paper is not inserted.

When white printing paper, that is, printing paper having a high light reflectance, is inserted, the sensor output 7 of the reflection type optical sensor 1 becomes high level, and the sensor output 8 of the reflection type optical sensor 2 also becomes high level. Therefore, the output of the AND circuit 6 becomes low level, which makes it possible to determine that the printing paper is inserted.

When a dark color printing paper, that is, a printing paper having a low light reflectance is inserted, the sensor output 7 of the reflection type optical sensor 1 becomes low level, and the sensor output 8 of the reflection type optical sensor 2 also. Since it becomes low level, the output of the AND circuit 6 becomes low level, which makes it possible to determine that the printing paper is inserted.

When a printing paper that has undergone format printing such as frame printing is inserted at the edge of the printing paper, the tip of the printing paper has a low light reflectance, so that the sensor output 7 of the reflection type optical sensor 1 is used. Becomes a low level, and the sensor output 8 of the reflection type optical sensor 2 also becomes a low level, so that the output of the AND circuit 6 becomes a low level. After passing the printed edge portion, the reflectance of light becomes high, so the sensor output 7 of the reflective optical sensor 1 becomes high level, and the sensor output 8 of the reflective optical sensor 2 also becomes high level. The output of the circuit 6 becomes low level.

Therefore, even in the case of a printing paper in which format printing such as frame printing is performed on the edge of the printing paper, the leading edge of the printing paper is detected as in the case of white or monochromatic printing paper. It can be determined that the printing paper is inserted.

[0029]

As described above, according to the present invention, in order to detect the presence or absence of print paper in a printer,
Two sets of paper detection sensors, a reflective optical sensor using a black reflective plate and a reflective optical sensor using a white reflective plate,
Since an inverter for inverting the output signal of the photosensor using the black reflector and an AND circuit for obtaining the logical product of the output signal of this inverter and the output signal of the photosensor using the white reflector are provided, It is possible to detect the presence / absence of paper for white printing paper, and it is possible to detect the presence / absence of paper for dark colored printing paper. Also, it is possible to provide an unprecedented excellent printing paper detection device that can detect the leading edge of the paper and determine the presence or absence of the paper.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an operation time chart of the embodiment shown in FIG.

FIG. 3 is a diagram illustrating an example of a sheet detection device of a conventional printer.

FIG. 4 is a diagram showing another example of a printing paper detection device of a conventional printer.

[Explanation of reference numerals] 1 reflection type optical sensor 2 reflection type optical sensor 3 black reflection plate 4 white reflection plate 5 inverter 6 AND circuit 11 light emitting element 12 light receiving element 21 light emitting element 22 light receiving element

Claims (3)

[Claims] 1. A printing paper detecting device for a printer having a reflection type optical sensor for detecting the presence or absence of a printing paper by reflected light from the printing paper, wherein a black reflecting plate is provided and printing is performed between the printing plate and the reflecting plate. A first reflection type optical sensor which, when a sheet is inserted, produces a high-level or low-level output according to the magnitude of the reflectance of the printing sheet, and produces a low-level output when the sheet is not inserted. , Which has a white reflector and produces high-level or low-level output according to the reflectance of the print sheet when the print sheet is inserted between the plate and the print sheet, and the print sheet is not inserted A second reflection type optical sensor that generates a high-level output, an inverter that inverts the output signal of the first optical sensor, an output signal of the inverter and an output signal of the second optical sensor Logical and a AND circuit for obtaining a print paper detecting device of the printer, characterized by determining the presence or absence of printing paper by the output of said AND circuit. 2. The first and second reflective photosensors each include a light emitting element, and a light receiving element that receives reflected light from an object based on light from the light emitting element and generates an output signal. It has what is characterized by the above-mentioned.
A printing paper detection device for the printer described. 3. The print sheet detection for a printer according to claim 2, wherein the first and second reflection type photosensors are each formed of a reflection type photocoupler having the light emitting element and the light receiving element. apparatus.