JPH0674828A - Line sensor device - Google Patents

Abstract

PURPOSE:To improve the spectrum separation characteristics for judging color density of natural colors by using blue cold cathode discharge tube for a light source and a light receiving element having a sensitivity characteristic with a sensitivity peak at green. CONSTITUTION:A blue cold cathode discharge tube 1 is used for a light source and a parabolic side surface-sighting reflector 6 of a film mirror and a photofiber 2 are equipped in a sensor case 10. The light receiving element on a light receiving plate 4 is to have sensitivity characteristic with sensitivity peak at green. The photofiber 2 is fixed in the case 10 and the reflector 6 and a focusing lens 3 are optically connected. The light beam from the discharge tube 2 is focused with the reflector 6, passes through the photofiber 2, diverged in the length direction of the case 10 and cast as sensor light on an inspected surface from the whole length of the lens 3 (whole length of the case 10). By this, the density change of three original clors (red, yellow, blue) for print color on the monitoring surface and black sensitively respond to the relection light change. Especially, the detection accuracy of judging color density change of yellow can be raised.

Description

Detailed Description of the Invention

[001]

BACKGROUND OF THE INVENTION The present invention is directed to surface monitoring devices (eg,
The present invention relates to a printing surface monitoring device in an online print quality control system of a continuous paper printing device. More specifically, it relates to a line sensor light source device in a surface monitoring device.

[002]

2. Description of the Related Art As a line sensor light source device of this type, one using a halogen lamp (incandescent bulb) as a light source and one using a white or daylight fluorescent lamp as a light source are known.

[003]

In the former halogen lamp light source, the life is short and maintenance is poor, a large amount of heat is generated and it is necessary to isolate it from other devices. There are problems such as poor characteristics (especially it is difficult to determine the change in yellow color density). The latter white or daylight fluorescent light source has problems that it has a large shape, is difficult to store in the same housing as the sensor body, and has poor spectral characteristics for determining the color density of natural color. Therefore, an object of the present invention is to solve the above-mentioned problems, and particularly to improve the spectral characteristics in performing color density determination of natural color.

[004]

According to the present invention, a blue cold cathode discharge tube is used as a light source, a side-view parabolic reflector is used to collect light, and a sensor beam is irradiated onto the surface to be inspected through an optical fiber. The light receiving element has a sensitivity characteristic having a peak.

[0095]

EXAMPLES The present invention will be described in detail below based on examples. 1 to 3, the sensor device is
The light source, the condenser lenses 3 and 3, the light receiving substrate 4, and the sensor substrate 5 are incorporated in the sensor case 10, and the sensor light beam is emitted toward the surface to be inspected (monitoring line A) and reflected by the surface to be inspected. The inspection of the surface to be inspected by injecting the reflected light beam to the element is similar to the known line sensor device.
In implementing the present invention, a blue cold cathode discharge tube 1 is used as a light source, and a parabolic reflector 6 of a film mirror in side view and an optical fiber 2 are provided in a sensor case 10. The light receiving element of the light receiving substrate 4 is a light receiving element having a sensitivity characteristic having a peak of green sensitivity.

Referring to FIG. 1, the optical fiber 2 is fixed to the sensor case 10 via the fiber guides 7, 8, the guide support 9, and the support plate 11. In FIG. 1, 12 is a fixture for the blue cold cathode discharge tube 1 and 13 is a mirror guide. The parabolic reflector 6 in side view and the condenser lens 3 are optically connected by the optical fiber 2, but the length of the condenser lens side end portion 2b is longer than the length of the blue cold cathode discharge tube side end portion 2a of the optical fiber 2. This is large (in the example, about twice with reference to FIG. 2). Therefore, since the total length of the blue cold cathode discharge tube 1 and the reflecting mirror 6 can be shortened as compared with the total length of the condenser lens 3, the blue cold cathode discharge tube 1 and the reflecting mirror 6 which are the light source are housed in the sensor case 10 and the sensor is provided. The sensor light can be emitted from the entire length of the case 10.
By connecting the sensor cases 10, a continuous linear light source can be formed from a finite length light source (that is, a light source device of a line sensor corresponding to a surface to be inspected having a desired width can be provided).

Light rays from the blue cold cathode discharge tube 1 which is a light source are condensed by the parabolic reflecting mirror 2 in side view, and the optical fiber 2
After that, the beam width is expanded in the longitudinal direction of the sensor case 10, and the sensor beam is irradiated from the entire length of the condenser lens 3 (the entire length of the sensor case 10) to the surface to be inspected.

By using the blue cold cathode discharge tube 1 as the light source and the light receiving element as the light receiving element having the sensitivity characteristic having the green sensitivity as a peak, the spectral characteristic for the color density discrimination of the natural color is improved (particularly It becomes clear by comparing with other light sources and light receiving elements having other sensitivity characteristics that the yellow color density change can be easily determined).

4 to 6 show a support structure for the sensor case 10, which is located above the monitoring line A,
A pair of support brackets 15 are loosely fitted to a horizontal support shaft 14 fixed to an appropriate support member, the sensor case 10 is fixed to the support brackets 15, and the sensor case 10 is rotated about the horizontal support shaft 14. A drive mechanism 16 including a support wheel freely supported by a horizontal support shaft 14 and equipped with a drive wheel for driving a motor is provided on one side of one support bracket 15.
A stopper (not shown) for restricting the rotation range of the sensor case 10 is provided so that the sensor case 10 can be freely rotated between a downward set position facing the monitoring line A and a lateral retracted position separated from the monitoring line A, and is always the same. The set position is maintained to ensure the set reproducibility of the set position, and is normally configured to be maintained at the set position.

[0101]

According to the present invention, since the light source is the blue cold cathode discharge tube, the change in reflected light sensitively responds to the change in the density of the three primary colors (red, yellow, blue) and black of the printing colors on the monitoring surface. thing,
By using the light receiving element having the sensitivity characteristic having the peak of the green sensitivity, the spectral characteristic for the color density determination of the natural color is improved, so that the detection accuracy of the yellow color density change determination can be particularly improved. Further, the temperature rise of the light source is small and the line sensor device can be downsized, and the parabolic reflecting mirror in side view can be used for effective light collection and strong sensor light. Even if the blue cold cathode discharge tube, which is the light source, is installed inside the sensor case because the optical fiber is inserted, the sensor beam can be emitted from the entire length of the sensor case, forming a continuous linear light source from a finite length light source. Therefore, there is an effect that a line sensor device corresponding to a monitoring surface having a desired width can be easily provided.

[Brief description of drawings]

FIG. 1 is a side view showing a line sensor device showing an embodiment of the present invention with an upper surface of a sensor case removed.

FIG. 2 is a front view of the line sensor device.

FIG. 3 is a side view showing the line sensor device with the side surface of the sensor case removed.

FIG. 4 is a front view showing a support structure of a sensor case.

FIG. 5 is a plan view of the same.

FIG. 6 is a side view of the same.

[Explanation of symbols]

 1 Blue cold cathode discharge tube 2 Optical fiber 4 Light receiving substrate

Claims (1)

[Claims] 1. A line sensor device for inspecting a surface to be inspected by irradiating a surface to be inspected with a sensor light beam, reflecting the light beam on the surface to be inspected, and injecting a reflected light beam to a light receiving element, wherein a light source is a blue cold cathode discharge tube. Then, it is condensed by a parabolic reflector in side view, passed through an optical fiber,
A line sensor device characterized by improving spectral characteristics by irradiating a surface to be inspected with a sensor beam and using a light receiving element as a light receiving element having a sensitivity characteristic having a peak green sensitivity.