JPH0324407A - Apparatus for detecting snaking amount of web - Google Patents

Abstract

PURPOSE:To make it possible to detect the slight snaking amount of developing paper accurate ly and to obtain a detecting device characterized by a simple structure and a low cost by moving a movable member in the direction that is approximately orthogonal to the conveying direction of the developing paper in following snaking when the developing paper is snaked. CONSTITUTION:A LED 10 which illuminates the edge part of developing paper 5 and a light receiving part 11 which receives the reflected light and detects a cut mark 7 are provided over a conveying system. Snaking of about + or -1 mm is formed on the developing paper 5 due to the slipping, eccentric turning of the conveying system and the like. A roller 18 which is attached to a movable member 20 is always in contact with the edge part of the developing paper 5 with a spring 27. Therefore, the movable member 20 is guided with pins 21 and 22 and moved back and forth in the direction orthogonal to the conveying direction following the snaking of the developing paper 5. Part of light emitted from a light projecting part 24 is shielded with a projection 20a which is provided at the movable member 20 a in a tapered shape. The other light is inputted into a light receiving part 25 and converted into an electric signal. The output signal from the light receiving part 25 is continuously changed largely with respect to the snaking amount of the developing paper. Thus, the delicate snaking amount of the developing paper 5 can be accurately measured without the effect of noises and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a web meandering amount detection device for detecting the meandering amount of a web such as photographic paper.

[Conventional technology]

As a web meandering amount detection device, one using a laser displacement meter is known. This is because when the edge of the web is irradiated with laser light, the displacement of the edge of the web with respect to the set reference position appears as a difference in the reflection position, so the diffusely reflected light from the edge of the web is focused and formed into an image on the sensor. The amount of meandering of the web is detected by measuring the position of this image. In addition, a light emitting element such as an LED is placed below the edge of the web so that the web partially blocks the light received by the photodiode array, and a photodiode array is placed above at right angles to the web conveyance direction. It is known that the amount of web meandering is detected by measuring changes in the amount of light received by a photodiode array.

[Problem to be solved by the invention]

However, those using the above laser displacement meter,
The disadvantage is that the structure is complex and the cost is high. Also,
For those using light emitting elements and photodiode arrays,
The pitch of the photodiode array is fixed, making it impossible to accurately detect delicate meandering. In addition, if the web is thin, the light from the light emitting elements will pass through the web, making it difficult to accurately detect meandering. The disadvantage is that it cannot be done.

[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 web meandering amount detecting device that can accurately detect even the slightest meandering amount of a web, has a simple structure, and is inexpensive. With the goal. [Means for Solving the Problems] In order to achieve the above object, the web meandering amount detection device of the present invention includes a rotating member that rotates in contact with the edge of the web being conveyed, and a rotating member that supports the rotating member. At the same time, a movable member that moves in a direction substantially perpendicular to the web conveyance direction following the meandering of the web, a taber-shaped protrusion formed integrally with this movable member, and a light emitting light arranged to sandwich this protrusion. It consists of a light-receiving part and a light-receiving part. [Operation] According to the above structure, when the web meanderes, the movable member follows the meandering and moves in a direction substantially perpendicular to the web conveyance direction. The movement of the movable member moves the tapered protrusion back and forth between the light projecting section and the light receiving section. As a result, the amount of light received by the light receiving section changes, so that the amount of meandering of the web is detected.

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

〔Example〕

FIG. 1 shows an embodiment in which the present invention is applied to a mark detection device that optically detects marks recorded on photographic paper. A plurality of images 6 are recorded at a constant pitch on the developed print 5, and cut marks 7 indicating cutting positions are also recorded between each image 6. This printing paper 5 is transported by a conveyance system (not shown) toward a cutter (not shown) for cutting each printed photograph. Above the conveyance system is an LED that illuminates the edge of the printing plate 5.
A light receiving section l1 is provided for detecting the cant mark 7 by receiving the light reflected at the edge. As shown in FIG. 2, this light receiving section 11 includes an optical sensor 13 such as a photodiode, and a light transmitting area 14a and a light blocking area 14b are set according to the amount of meandering, and the field of view (measurement range) of the optical sensor 13 is set.
Turn ON/OFF so that it matches the path of cut mark 7.
It is composed of a liquid crystal mask 14 to be controlled, a lens 15 that images the light reflected by the printing plate 5 on the optical sensor 13, and a housing 16 that houses these.

On the side of the conveyance system, a roller 18 that is rotated while abutting against the edge of the photographic paper 5 is attached to the upper part of the movable member 20 via a shaft 19. This movable member 20 has a triangular protrusion 20a, and is arranged to be movable forward and backward in a direction perpendicular to the conveying direction of the photographic paper 5 via pins 21 and 22. Above the protrusion 20a, an elongated light projecting section 24 such as an LED that emits uniform light downward is provided in a direction perpendicular to the moving direction of the protrusion 20a. In addition, the protrusion 20a
An elongated light receiving section 25 such as a photodiode that receives the irradiated light from the light projecting section 24 is arranged below the light projecting section 24 so as to face the light projecting section 24 with the protrusion 20a in between. The movable member 20 is urged toward the photographic paper 5 by a spring 27 so that the roller 18 is always in contact with the edge of the photographic paper 5. Each of these members constitutes a meandering amount detection device.

The light receiving section 25 includes an amplification circuit 31 that amplifies its output.
A meandering amount detection circuit 32 detects the meandering amount of the printing paper 5 based on the output signal of the amplifier circuit 31, and a meandering amount detection circuit 32 detects the meandering amount of the printing paper 5 based on the meandering amount of the printing paper 5. A liquid crystal mask opening/closing control section 33 that sets the liquid crystal mask opening/closing control section 33 and a driver 34 that drives the liquid crystal mask 14 according to a drive signal from the liquid crystal mask opening/closing control section 33 are connected in this order.

Next, the operation of the mark detection device configured as described above will be explained. The light emitted from the LEDIO is
illuminate the edges of the The light reflected from this edge is incident on the lens 15, and is transmitted through the light transmission area 14a of the liquid crystal mask l4.
The light passes through and is imaged on the optical sensor 13. When the cut mark 7 passes below the light receiving section 11 while the print 5 is being transferred, a change appears in the output signal of the optical sensor l3, so that the cut mark 7 is detected. Based on this cut mark detection, a cutter is operated in a well-known manner to cut the photographic paper 5 on an extension line of the cut mark 7 to separate one frame of a printed photograph.

Printing size 5 is ±1 due to slips in the conveyance system, eccentric rotation, etc.
Meandering occurs within a range of about mm. Here, since the roller l8 is always in contact with the edge of the printing paper 5 due to the action of the spring 27, the movable member 20 follows the meandering of the printing paper 5.
It is moved back and forth in a direction perpendicular to the conveying direction while being guided by pins 21 and 22.

A part of the light emitted from the light projector 24 is blocked by the protrusion 20a, and the other light enters the light receiver 25 and is converted into an electrical signal.

In FIG. 3, the standard positions of the photographic paper 5 and the movable member 20 during conveyance are shown by solid lines, and the state in which they have meandered and moved is shown by two-dot chain lines. From the same figure, the light receiving part 25 is located at the protrusion 2.
It can be seen that the range of light shielded by 0a changes greatly even with a slight meandering of the photographic paper 5. therefore,
Since the output signal of the light receiving section 25 changes continuously and greatly in response to the meandering amount of the photographic paper 5, the delicate meandering amount of the printing paper 5 can be accurately converted into an electrical quantity without being affected by noise etc. It will be done. The signal output from the light receiving section 25 is inputted to the meandering amount detection circuit 32 via the amplifier circuit 31, and the meandering amount of the photographic paper 5 is detected. The liquid crystal mask opening/closing control unit 33 drives the liquid crystal mask 14 via the driver 34 based on the amount of meandering of the photographic paper 5, and sets the light transmitting area 14a and the light blocking area 14b. Therefore, the optical sensor l3 measures only a range including the cut mark 7 of a certain width from the edge of the photographic paper 5,
Image 6 is not mistakenly detected as cut mark 7. In the embodiment described above, the meandering amount detection device of the present invention is used to control a liquid crystal mask, but a mask is provided to limit the measurement range of the optical sensor, and a solenoid that drives this mask is controlled based on the meandering amount. It may be controlled by Moreover, the present invention also provides the Web snake 4. It can also be used to attenuate rows. For example, a spitting roller is arranged in the web conveyance system, and the position of this roller is controlled based on the meandering amount detected by the device of the present invention,
What is necessary is to attenuate the meandering of the web.

〔Effect of the invention〕

As described above, according to the meandering amount detection device of the present invention, the movable member is provided with a tapered projection so as to move in a direction substantially perpendicular to the conveyance direction of the web, following the meandering of the web. The light emitting part and the light receiving part are arranged to sandwich the protrusion, and the amount of meandering of the web is detected from the change in the amount of light received by the light receiving part based on the movement of the protrusion, so the structure is simple and low cost. However, even the slightest meandering amount of the web can be detected accurately.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment in which the present invention is applied to a mark detection device. FIG. 2 is a sectional view showing the structure of the main part of the embodiment shown in FIG. Figure 3 is a plan view of the meandering detection device shown in Figure 1. 5 . . . . . 7 . Components, protrusions, and light emitting parts.

Claims (1)

[Claims] (1) A rotating member that rotates in contact with the edge of the web being conveyed, a movable member that supports this rotating member and moves in a direction substantially perpendicular to the web conveying direction following the meandering of the web; It consists of a tapered protrusion formed integrally with a movable member, and a light emitting part and a light receiving part arranged to sandwich this protrusion.The amount of meandering of the web can be determined from changes in the amount of light received by the light receiving part based on the movement of the protrusion. A web meandering amount detection device characterized by detecting.