JPH0339742A - Mark detecting method - Google Patents

Abstract

PURPOSE:To detect a mark even when a distance between a long substance and a photodetector and an angle by the long substance with a photodetector are changed by judging and detecting the mark on the long substance in the case that a difference between a 1st detected result and a 2nd detected result obtained after conveying the long substance by a specified distance is equal to or exceeding a specified value. CONSTITUTION:The surface of the long substance 12 is irradiated with light from a light source 18 and the light reflected on the long substance 12 is detected by the photodetector 20 firstly. After the long substance 12 is conveyed by the specified distance, the light is detected by the photodetector 20 secondly. When the difference between the 1st detected result and the 2nd detected result is equal to or exceeding the specified value, it is judged that the mark 14 exists on the long substance 12, and the mark 14 on the long substance 12 is detected. Thus, the mark 14 recorded on the long substance 12 is detected even when the distance between the conveyed long substance 12 and the photodetector 20 and the angle by the long substance 12 with the photodetector 20 are changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mark detection method for detecting marks recorded on an elongated object while the elongated object is being conveyed.

[Prior Art] On the widthwise end of a long piece of photographic paper, for example, there are cut marks that are cut into each shank, or prints that are cut into each shank, corresponding to the images recorded on the photographic paper. Sort marks used when sorting paper are recorded.

The markers recorded on the photographic paper are detected by a sensor head fixed to a printing device or the like while the long photographic paper is being conveyed.

In this detection, light is emitted from a fixed light source from the front or back side of the photographic paper, and a sensor detects the presence or absence of light reflected on the photographic paper.

[Problems to be Solved by the Invention] However, the conveyed photographic paper may meander in the width direction, and the reflected light of the light irradiated onto the photographic paper may deviate from the detection surface of the detector. In this case, there is a problem that the mark cannot be detected.

Furthermore, the distance from the light source changes due to flapping of the photographic paper being conveyed, or the photographic paper is tilted with respect to the conveyance direction due to curls caused by poor drying, etc., and the photographic paper is exposed to light irradiated from the light source onto the photographic paper. The reflection angle of the reflected light may change and the light may not be incident on the detector. For this reason, marks on photographic paper could not be detected reliably. Furthermore, since there is a difference in the amount of reflected light depending on the surface condition, the mark-slice-lever method at a certain value tends to lead to misreading.

In consideration of the above facts, the present invention has been developed to detect marks recorded on a long body even if the conveyed long body changes in distance or angle with respect to the detector. The purpose is to provide a method.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for transporting the elongated object a predetermined distance after first detecting the reflected light of the light irradiated onto the elongated object using a photodetector. , when the reflected light of the light irradiated from the light source to the elongated body is second detected by a photodetector, and the difference between the first detection result and the second detection result is more than a predetermined value. The present invention is characterized in that it determines that a mark exists on the elongated body and detects the mark on the elongated body.

[Function] In the present invention having the above configuration, light is irradiated from the light source onto the surface of the elongated body, and the light reflected by the elongated body is subjected to the first detection using the photodetector. Next, the elongated body is transported a predetermined distance, and a second detection is performed by a photodetector.

If the difference between the first detection result and the second detection result is greater than or equal to a predetermined value, it is determined that a mark exists on the elongated body, and the mark on the elongated body is detected.

[Effects of the Invention] In the present invention having the above configuration, it is determined that there is a mark on the elongated object when the difference between the first detection result and the second detection result after being transported a predetermined distance is equal to or greater than a predetermined value. Since the mark on the long object is detected, the mark can be detected even if the distance or angle of the transported long object changes with respect to the photodetector, thereby preventing misreading of the mark. An excellent effect can be obtained in that it can prevent.

[Embodiment] FIG. 1 shows an embodiment of a mark detection device 10 for detecting a mark 14 recorded on photographic paper 12 using a mark detection method according to the present invention. This mark detection device lO
A pair of conveying rollers 16 are disposed on the conveyor rollers 16, and the conveyor rollers 16 are rotated by being transmitted with the driving force of a driving means (not shown). The photographic paper 12 is held between the transport roller pair 16 and is transported in the direction of the arrow shown in FIG.

On the downstream side of the pair of transport rollers 16 in the direction in which the photographic paper 12 is transported, an LED 18 that emits a light source is arranged above the transport path. This LED 18 is connected to a power supply (not shown) to emit light, and irradiates light onto the slit-shaped marks 14 exposed and recorded between the frames on the photographic paper 1.2. The incident angle of the light from this LED 18 is inclined with respect to the vertical direction, and the light is arranged so that the reflected light of the light irradiated onto the photographic paper 12 is incident on the photodetector 20. There is.

The photodetector 20 is arranged between the LED 18 and the pair of transport rollers 16, and the light reflected on the photographic paper 12 is incident thereon. When light is incident on the detection surface, this photodetector 20 generates a voltage corresponding to the amount of light and outputs an electric signal corresponding to the amount of light.

As shown in FIG. 2, the photodetector 20 is connected to an amplifier circuit 22, and outputs an electric signal corresponding to the detected light to the amplifier circuit 22. The amplifier circuit 22 amplifies the input electrical signal and outputs it to the A/D converter 24.

The A/D converter 24 digitizes the analog electrical symbol corresponding to light and outputs this digital signal to the CPU 26. Further, an encoder 28 is connected to the A/D converter 24 and is connected to the transport roller pair 16 to detect the rotation angle of the transport roller pair I6. The signal output from this encoder 28 (feed angle of conveyance roller pair 16) is A/
The analog signal is input to the D converter 24 and converted into a digital signal. The encoder 28 is also connected to the CPU 26, and outputs a pulse signal that rotates the pair of conveyance rollers 16 in basic units.

A RAM 30 is connected to the CPU 26, and the detected amount of light reflected on the photographic paper is stored as an electric signal. Also, the detected photographic paper 1 stored in this RAM 30
The amount of light reflected by 2 is read into the CPU 26 as necessary. Further, when the CPU 26 determines that a mark has been detected, it outputs a mark detection signal.

Next, a mark detection method for detecting marks recorded on the photographic paper 12 conveyed by the above-described mark detection device 10 will be explained using the flowcharts shown in FIGS. 3 and 4.

When the transport roller pair 16 is driven by a drive means (not shown), transport of the photographic paper 12 is started.

At the same time, mark detection is performed in the order shown in FIG.

Amount Q of reflected light reflected on the photographic paper 12 in step 100
, is detected by the photodetector 20.

This result is converted into an electrical signal and stored in the RAM 30. Next, in step 102, it is determined whether the photographic paper 12 has been conveyed a predetermined distance. This predetermined distance is set within about one mark. Further, conveyance of the photographic paper 12 over a predetermined distance is detected by the encoder 28, and this result is sent to the CPU 2.
6, and based on this information, the CPU 26 controls the operation of a drive means (not shown) to control the rotational speed of the conveying roller pair 16.

When the photographic paper 12 is conveyed a predetermined distance, step 104
Then, the light m Q 2 is again detected by the photodetector 20 in the reflected light reflected by the photographic paper 12 . In step 106, a difference L4 between the amount of light before transporting a predetermined distance and the amount of light Q2 after transporting a predetermined distance is calculated.

Next, in step 108, the light it Q l and the light 11Q,
A comparison is made between the difference between the two and a predetermined value P. In this comparison, if the difference I is smaller than the predetermined value P, the process returns to before step 102 and the following steps are executed again.

If the difference in the amount of light before and after transporting the photographic paper 12 is greater than or equal to the predetermined value P, the mark 14 is present, so the mark is detected in step 112 after replacing the amount of light Q2 with the amount of light Q in step 110. The CPO 26 outputs the signal.

Here, the relationship between the signal that is incident on the photographic paper 12, converted into an electrical signal, and outputted from the photodetector 20, and the conveyance of the photographic paper 12 will be explained using FIG.

The diagram shown in FIG. 3 represents the signal output from the photodetector 20. The signal output from the photodetector 20 has large undulations as shown in FIG. This undulation occurs because the reflected light incident on the photodetector 20 changes as the photographic paper 12 meanders in the width direction or moves in the thickness direction while being conveyed.

In this diagram, a portion M protrudes downward.

~M6 is a portion where the light reflected by the mark portion is incident. That is, the mark 1 recorded by exposure on the surface of the photographic paper 12
The amount of light reflected by the photodetector 20 is small, and therefore the signal output from the photodetector 20 is small.

In this figure, if the predetermined conveyance distance is a constant distance S, the difference ΔL in light amount between Ml and M2 shown in FIG.
Difference ΔQ between the light intensity at part M3 and the light intensity a distance S before there
smaller. Therefore, the difference between the amount of light detected before transporting a predetermined distance S and the amount of light detected after transporting a predetermined distance S is set to a predetermined value P.
It can be determined whether or not a mark has been detected by comparing with .

Here, the predetermined distance S is 1 mI! It is set to l≦3<4 mm, preferably 2 mm.

In step 114, it is determined whether or not the conveyance of the photographic paper 12 has stopped, and if it has not, the process returns to before step 102 and the following steps are repeated. The process ends when the conveyance of the photographic paper 12 stops.

In this embodiment, photographic paper is used as an example of the elongated body, but the present invention is not limited to this, and the present invention can be applied to any elongated body on which marks are recorded.

Further, in this embodiment, the means for conveying the photographic paper 12 a predetermined distance is a pair of conveyance rollers 16, and the encoder 28 is used to detect whether or not the photographic paper 12 has been conveyed a predetermined distance. Any conveying means may be used as long as it can accurately convey a predetermined distance.

Furthermore, although a photodetector is used in this embodiment to detect reflected light and transmitted light, any detector that can detect reflected light and transmitted light from photographic paper 12 may be used.

Further, in this embodiment, LEDs 16 and 18 are used as light sources, but lamps or other light sources may be used.

[Brief explanation of drawings]

Fig. 1 is a perspective view schematically showing a mark detection device to which the present invention is applied, Fig. 2 is a block diagram showing a circuit to which a photodetector is connected, and Fig. 3 is a conveyance distance between the photodetector and photographic paper. FIG. 4 is a flowchart showing the mark detection method. 10... Mark detection device, 12... Photographic paper, 14... Mark, 18... LED. 20... Photodetector.

Claims (1)

[Claims] (1) A mark detection method that detects marks recorded on a long body while transporting the long body, in which the reflected light of the light irradiated to the long body is first detected by a photodetector. Afterwards, the elongated object is conveyed a predetermined distance, and the reflected light of the light irradiated from the light source to the elongated object is subjected to a second detection using a photodetector, and the result of the first detection and the result of the second detection are combined. 1. A mark detection method comprising: determining that a mark exists on an elongated object when the difference between the two is greater than a predetermined value, and detecting the mark on the elongated object.