JPH0312653A - Mark detecting device - Google Patents

Abstract

PURPOSE:To obtain sufficient illuminance, to reduce the unevenness of the illuminance on a measurement surface and to surely detect a mark by setting the optical axis of a photosensor perpendicular to the surface of a photographic paper and making the intersection of the optical axis of the photosensor and the surface of the photographic paper closer to a high-brightness LED side than the intersection of the optical axis of the high-brightness LED and the surface of the photographic paper. CONSTITUTION:The high-brightness LED 14 is installed at a position where the intersection A of the optical axis La of the photosensor 15 and the photographic paper 10 is made closer to the high-brightness LED 14 side than the intersection B of the optical axis Lb of the high-brightness LED 14 and the photographic paper 10. Therefore, the illuminance on the measurement surface 17 by the directional characteristics curve 16 of the high-brightness LED 14 becomes as shown by a distribution curve 18, and the illuminance is the highest in the light receiving range S1 of the photosensor 15, where the illuminance distribution becomes nearly uniform. When the cut mark 11 of the fed photographic paper 10 is within the light receiving range S1, a remarkable change is brought on an output signal from the photosensor 15, so that the cut mark 11 can be surely detected. Thus, the sufficient illuminance is obtained, the illuminance distribution of the measurement range is uniformized and the mark is accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mark detection device for detecting marks recorded on developed photographic paper.

[Conventional technology]

A long sheet of photographic paper that has been printed and developed is cut frame by frame using a cutter, and then sorted into orders. During this cutting and sorting, marks such as cut marks indicating the cutting position and sorting marks for sorting by order are imprinted on the edges between the images when the photo is printed, and these are detected by a mark detection device. Then, they are cut and sorted. This mark detection device consists of a light emitter that illuminates the edge of the photographic paper, and a light sensor that detects the mark by receiving the light reflected from the edge. Generally, LEDs with wide directional characteristics are used to reduce uneven illuminance.

[Problem to be solved by the invention]

However, LEDs with wide directional characteristics have low luminance, and if the distance between the LED and the measurement surface or the distance between the measurement surface and the optical sensor is long, less light will be incident on the optical sensor, making it difficult to detect marks. Become.

In addition, high-brightness LEDs with high luminance are also known,
Since this high-intensity LED has strong directional characteristics, if used as is, uneven illuminance will occur on the measurement surface.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a mark detection device that can obtain sufficient illuminance, reduce illuminance unevenness on a measurement surface, and reliably detect marks. With the goal.

[Means to solve the problem]

In order to achieve the above object, the mark detection device of the present invention uses a high-intensity LED with sharp directional characteristics, sets the optical axis of the optical sensor perpendicular to the surface of the photographic paper, and aligns the optical axis of the optical sensor with the surface of the photographic paper. The intersection point is located closer to the high-intensity LED than the intersection between the optical axis of the high-intensity LED and the printing paper surface.

[Effect]

According to the above configuration, since the high-intensity LED is arranged offset from the optical axis of the optical sensor, high-intensity and uniform illumination is performed over a considerable range of the measurement surface.

A portion of this uniformly illuminated range becomes the light receiving range of the optical sensor. When a mark made on the photographic paper surface crosses this light-receiving range, the output signal from the optical sensor changes markedly.
Accurate mark detection is performed.

Embodiments of the present invention will be described in detail below with reference to the drawings.

〔Example〕

In FIG. 1 showing the mark detection device of the present invention from the side, a plurality of images are recorded at a partial pitch on a developed photographic paper 10, and cut marks 11 indicating cutting positions are shown between each image. is also recorded. The photographic paper 10 is transported by a transport system (not shown) toward a cutter for cutting each print into individual photographs.

The mark detection device includes two high-brightness LEDs with sharp directional characteristics and high luminance, and a light sensor such as a photodiode.
It consists of 5. This optical sensor 15 is arranged so that its optical axis La is perpendicular to the photographic paper 10.

The high-intensity LED 14 is connected to the optical axis La of the optical sensor 15.
The intersection point A between and the photographic paper 1o is the optical axis Lb of the high-intensity LED 14.
It is provided at a position closer to the high-intensity LED 14 than the intersection B between the LED and the photographic paper 10. As a result, the intersection A is located at the center of the illumination area illuminated by the high-intensity LED 14 where the illuminance distribution is uniform. Note that since the illuminance distribution also changes depending on the angle θ between the optical axis La and the optical axis Lb, the angle is set to the angle that causes the least unevenness in illuminance.

Next, the operation of the mark detection device configured as above will be explained. Light emitted from the high-intensity LED 14 is directed toward the edge of the photographic paper 10. High brightness LED
In FIG. 2 showing the directional characteristic curve 16 of the sensor 14 and the illuminance distribution curve 18 on the measurement surface I7, the light receiving range S of the optical sensor 15 is the range where the illuminance is the highest and the illuminance distribution is almost uniform. . Therefore, when the cut mark 11 of the transferred photographic paper 10 enters the light receiving range Sl, a noticeable change appears in the output signal of the optical sensor 15, so that the cut mark 11 can be reliably detected.

FIG. 3 shows a conventional mark detection device using brightness LEDs. In this conventional example, the intersection between the optical axis La of the optical sensor 15 and the measurement surface 17 coincides with the intersection between the optical axis Lb of the high-intensity LED 14 and the measurement surface 17, and the light receiving range S2 of the optical sensor 15 is is a range in which the illuminance distribution on the measurement surface 17 is non-uniform. Therefore, cut mark 1
1 is the light receiving range S! Since it is difficult for the output signal of the optical sensor 15 to show a clear change even when the cut mark 11 is detected, the detection of the cut mark 11 becomes uncertain.

The embodiment described above is for detecting cut marks, but
The present invention can also be used to detect sorting marks used for sorting orders. Also, 2
The measuring surface may be illuminated from both sides using several brightness LEDs.

〔Effect of the invention〕

As described above, according to the mark detection device of the present invention, the LED
A high-intensity LED with sharp directional characteristics is used as a directional characteristic, and the optical axis of the optical sensor is set perpendicular to the photographic paper surface, and the intersection of the optical axis of the optical sensor and the photographic paper surface is set at 4 degrees between the optical axis of the brightness LED and the photographic paper surface. The luminance LE from the intersection of
Since it is placed on the D side, sufficient illuminance can be obtained, the illuminance distribution in the measurement range can be made uniform, and accurate mark detection can be performed.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention. FIG. 2 is a schematic diagram showing the relationship between the illuminance distribution and the light receiving range in the embodiment shown in FIG. FIG. 3 is a schematic diagram showing the relationship between the illuminance distribution and the light receiving range in a conventional example using brightness LEDs. Photographic paper cut mark Light intensity LED Light sensor directional characteristic curve Illuminance distribution curve. Figure 2 10 (tIJ Association, K)

Claims (1)

[Claims] (1) LE that irradiates illumination light onto the surface of developed photographic paper
A mark detection device comprising a light sensor D and an optical sensor that receives reflected light from the surface of the photographic paper and detects a mark made on the surface of the photographic paper, wherein a high-intensity LED with sharp directional characteristics is used as the LED,
A mark characterized in that the optical axis of the optical sensor is set perpendicular to the surface of the photographic paper, and the intersection of the optical axis of the optical sensor and the surface of the photographic paper is closer to the LED than the intersection of the optical axis of the LED and the surface of the photographic paper. Detection device.