JPH0593698A - Detecting apparatus of imperfection of external appearance of color sheet - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a color sheet appearance defect detection device that does not require a mechanical device for changing an aperture and simplifies the device. [Structure] An appearance defect of the color sheet 40 is received by a transmitted light or a reflected light of the light emitted from the light source 1 to the color sheet 40. C
A device for detecting based on the output of the image pickup unit using the CD line sensor 2, which is a sheet color signal setting unit 6 for outputting a color signal corresponding to the color of the color sheet 40, and the sheet color signal setting unit 6 CC based on the output color signal
The configuration is provided with a storage time adjusting unit 5 that adjusts the storage time of the D line sensor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an appearance defect detection device for detecting appearance defects such as pinholes and foreign matters existing on the surface of a color sheet.

[0002]

2. Description of the Related Art FIG. 5 shows a manufacturing process of a color sheet.

Base roll 31 and comma roll coater 3
2 is provided close to each other, and the process paper 33, which is the base material of the color sheet wound around the base roll 31, passes through the gap between the base roll 31 and the comma roll coater 32, and is in the direction of arrow A in the figure. And is taken up by the take-up roll 36 (see FIG. 4). Further, the base roll 31 is provided with a solvent accommodating portion 35 for accommodating the solvent 34 in a portion around which the process paper 33 is wound, and the comma roll coater 32 is soaked in the solvent 34 around its lower half. Are arranged as follows.

That is, the process paper 33 is the base roll 3
When the surface is immersed in the solvent 34 when it orbits around 1, and is taken up by the winding roll 36 through the gap between the base roll 31 and the comma roll coater 32, unnecessary solvent 3
4 is removed, and the solvent 3 having a predetermined thickness is formed on the surface of the process paper 33.
The color sheet 40 coated with No. 4 is manufactured. That is, the coating thickness of the solvent 34 can be adjusted by adjusting the gap between the base roll 31 and the comma roll coater 32.

In the manufacturing process of such a color sheet 40, spot-like defects such as so-called blurring and cissing occur due to various causes.

Blurring is mainly caused by the comma roll coater 3
Paper dust, dust, and the like adhere to the surface of No. 2, and the cross-sectional shape of that portion is as shown in FIG. That is,
The thickness of the solvent 34 applied on the process paper 33 is reduced by that portion. Its diameter is about 2 mm.

Repelling is mainly caused by the air in the solvent 34 passing through the gap between the base roll 31 and the comma roll coater 32, and the cross-sectional shape of that portion is as shown in FIG. .. That is, the solvent 34 applied on the process paper 33 is lost only in that portion. Its diameter is about 1 mm.

As described above, in the manufacturing process of the color sheet, various kinds of appearance defects as described above occur. Therefore, conventionally, there has been provided an apparatus for automatically detecting the appearance defects.

FIG. 4 shows an example of a conventional apparatus for detecting such a defective appearance of a color sheet. In this conventional device, the surface of the color sheet is photographed by the CCD line sensor 12, and the appearance defect of the color sheet is detected by the output voltage of the CCD line sensor.

Here, the output voltage of the CCD line sensor 12 is represented by the product of the CCD sensitivity, the sensor surface illuminance, and the storage time. However, since the reflectance and the transmittance differ depending on the color of the color sheet 40, the illuminance on the sensor surface changes and C
The output voltage of the CD line sensor 12 also changes. Therefore, in the color sheet 40 where the sensor surface illuminance is low,
The output voltage required for determining the appearance defect cannot be obtained, and the appearance defect cannot be determined.

Therefore, in order to eliminate such a problem,
In the conventional apparatus, the aperture of the lens is changed according to the color of the color sheet 40.

In the figure, in the vicinity of the color sheet 40 pulled from the base roll 31 to the take-up roll 36 side, the process paper 33 side (the lower side of the color sheet 40 in the drawing).
The light source 11 is arranged in the
A CCD line sensor 12 for inputting a surface image of the color sheet 40 is arranged on the opposite side (upper side of the color sheet 40 in the drawing).

In this CCD line sensor 12, a gear 14 is attached to the diaphragm portion 13 of the lens, and a gear 15 meshing with the gear 14 is driven by a drive portion 16 so that the diaphragm of the diaphragm portion 13 is reduced. It can be changed arbitrarily. The output of the color code input unit 19 for inputting the color code is led to the aperture setting unit 18, and the output of the aperture setting unit 18 is led to the control unit 17. The output of the control unit 17 is guided to the drive unit 16.

That is, in the aperture setting unit 18, the aperture is preset for each color code of the color sheet 40, and when the color code of the currently manufactured color sheet 40 is input from the color code input unit 19, the aperture is set. The aperture data according to the color code is sent to the control unit 17. The control unit 17 drives and controls the drive unit 16 according to the aperture data, and the drive unit 16 controls the gear 1
The diaphragm of the diaphragm unit 13 is changed via 5, 14.

That is, the lens diaphragm is changed by the diaphragm unit 13.
This is done by mechanically driving the gear 14 attached to the drive unit 16 by the drive unit 16.

In this way, by changing the diaphragm of the diaphragm 13 of the lens according to the color of the color sheet 40 and adjusting the amount of light incident on the sensor surface of the CCD line sensor 12, a color having low sensor surface illuminance. The seat 40 is also compatible.

[0017]

As described above, in the conventional appearance defect detecting device, the diaphragm is mechanically changed in order to keep the output voltage of the CCD line sensor 12 at a constant level regardless of the color of the color sheet 40. Therefore, high accuracy is required for the apparatus itself, and the apparatus becomes complicated. A drive system (gear 14, 15) for changing the diaphragm around the lens
In addition, there are various problems that the apparatus itself becomes large and maintenance becomes difficult.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an appearance defect detection device for a color sheet, which does not require a mechanical device for changing an aperture and simplifies the device. To do.

[0019]

In order to solve the above-mentioned problems, an appearance defect detecting device for a color sheet according to the present invention provides an appearance defect of the color sheet, which is transmitted light or reflected light of light emitted from a light source to the color sheet. A sheet color setting unit for outputting a color signal corresponding to a sheet color, which is a device for detecting based on an output of an image pickup unit using a CCD line sensor for receiving
Based on the color signal output from this sheet color setting unit,
And a storage time adjusting unit for adjusting the storage time of the CCD line sensor.

[0020]

In the sheet color setting section, the color code of the color sheet is set. As a setting method, there is a method of inputting a color code by an operator.

There is also a method of automatically identifying and inputting the color of the color sheet being manufactured. That is, the color code is held as data corresponding to the average value of the output voltage of the CCD line sensor when the storage time (scan rate) is constant for each color sheet, and the output voltage of the CCD line sensor is set at the initial stage of manufacturing. By calculating the average value of
It is possible to automatically determine and set the color code.

In the accumulation time adjustment unit, the accumulation time is set in advance corresponding to the color code of each color sheet, and the accumulation time is determined according to the color code sent from the sheet color setting unit. That is, the accumulation time is set to be long for color sheets with low sensor surface illuminance, and the accumulation time is set to be short for color sheets with high sensor surface illuminance. Is set so that it is at a substantially constant level.

As a result, the output voltage of the CCD line sensor is always output as a constant level regardless of the color of the color sheet. Therefore, the appearance defect determination section determines the appearance defect based on the output voltage of the constant level. To do. That is, since the transmitted light from the light source increases in the portion where the appearance defect occurs, the level of the output voltage of the CCD line sensor in this portion increases. Therefore, the appearance defect determination unit determines that the appearance is defective when the increased level exceeds the threshold value within the predetermined time width S (see FIG. 3). Here, the predetermined time width S is set so that when the output voltage level exceeds the threshold value for a moment due to noise or the like generated in the circuit, it is determined that the appearance is not defective and an erroneous determination is made. This is to prevent this from being done.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the electrical construction of a color sheet appearance defect detecting apparatus according to the present invention.

In the figure, in the vicinity of the color sheet 40 pulled from the base roll 31 to the take-up roll 36 side, the process paper 31 side (the lower side of the color sheet 40 in the drawing).
The light source 1 is disposed in the color sheet 40, and the color sheet 40 is provided on the side opposite to the light source 1 via the color sheet 40 (the upper side of the color sheet 40 in the drawing).
A CCD line sensor 2 for inputting the surface image of is arranged.

The CCD line sensor 2 includes a drive unit 4
Output of the CCD line sensor 2
Output is guided to the appearance defect determination unit 7.

The drive section 4 is composed of a clock pulse generation circuit 8 for generating a read pulse (clock pulse) per bit and a start pulse generation circuit 9 for generating a read pulse (start pulse) per line. ing.

The output of the sheet color setting section 6 is led to the accumulation time adjusting section 5, and the output of the accumulation time adjusting section 5 is led to the start pulse generating circuit 9.

The sheet color setting section 6 is adapted to set the color code of the color sheet. The setting method may be either a method of inputting a color code by the operator or a method of automatically determining and inputting a color of a color sheet being manufactured.

The storage time adjusting unit 5 has a storage time corresponding to the color code of each color sheet as a database. That is, the accumulation time of the color sheet having the highest sensor surface illuminance is set to the shortest, and the accumulation time of the color sheet having the lowest sensor surface illuminance is set to the longest. As a result, the output voltage of the CCD line sensor 2 is set to a substantially constant level regardless of the color sheet.

That is, since the output voltage of the CCD line sensor 2 becomes substantially constant when the surface of the color sheet 40 having no appearance defect is photographed, the threshold value for determining the appearance defect is set to the threshold value of the color sheet. It can always be set to a constant level regardless of color.

FIG. 2 shows the relationship between the storage time in the CCD line sensor 2 and the output voltage level. When the accumulation time of the CCD line sensor 2 which inputs the surface image of the color sheet with low sensor surface illuminance is short, the output voltage level B1 of the CCD line sensor 2 is also low as shown in FIG.
Output voltage level (base level) of defective part
It is a low level that is not much different from B1. Therefore, the comparison with the set threshold value T becomes impossible. On the other hand, if the accumulation time of the CCD line sensor 2 which inputs the surface image of the color sheet with low sensor surface illuminance is increased, the output voltage level (base level) B2 of the CCD line sensor 2 is also increased as shown in FIG. Therefore, the level of the defective portion also becomes higher than the output voltage level B2, and comparison with the threshold value T becomes possible.

In this embodiment, the light source 1 is a direct current fluorescent lamp and the CCD line sensor 2 is three 2048-bit ones, and the resolution is 0.22 mm. Further, the irradiation method adopts a transmission method, the line speed of the color sheet 40 is 15 m / min, and the sheet width is 1300 mm.

Next, the operation of the appearance defect detecting device having the above structure will be described with reference to the graph showing the relationship between the accumulation time and the output voltage shown in FIG.

First, the manufacturing of the color sheet 40 is started by the manufacturing process shown in FIG.

At this time, the back surface of the color sheet 40 (process paper 3
Light is radiated from a DC straight tube fluorescent lamp from the 3 side). Then, the light transmitted through the color sheet 40 is received by the CCD line sensor 2.

When the color code is set by a person, the sheet color setting section 6 sends the color code input by the operator to the accumulation time adjusting section 5, and the accumulation time adjusting section 5 uses this color code. The storage time corresponding to is read from the database and given to the start pulse generation circuit 9. The start pulse generation circuit 9 adjusts the generation timing of the start pulse for reading one line according to the accumulated time data. That is, when the color code indicates that the color sheet 40 has low sensor surface illuminance,
The generation timing of the start pulse is adjusted so as to be delayed by that amount, and the color code of the color sheet 40 whose color code is high on the sensor surface
If it indicates that the start pulse generation timing is adjusted to be earlier by that amount.

The CCD line sensor 2 reads the charge accumulated in the CCD line sensor 2 for a predetermined time in accordance with the start pulse from the start pulse generating circuit 9. Therefore, the accumulated charges read from the CCD line sensor 2 are always kept at a constant level. The read accumulated charge is output to the appearance defect determination unit 7.

The appearance defect judging section 7 compares the output voltage level B of the CCD line sensor 2 with a threshold value T set inside, and the output voltage level B keeps the threshold value T within a predetermined time S. When the width exceeds the width, it is determined that the appearance defect has occurred.

Based on this determination signal, it is possible to take measures such as automatically stopping the manufacturing apparatus or sounding an alarm device to notify the operator of the appearance defect.
It is also possible to calculate the defect occurrence rate per unit area of the color sheet 40 to determine the quality of the product.

[0042]

The color sheet appearance defect detecting apparatus according to the present invention includes a sheet color setting section for setting the color applied to the sheet, and a CCD line sensor based on the color set by the sheet color setting section. A configuration including a storage time adjustment unit that adjusts the storage time, and an appearance defect determination unit that determines the appearance defect of the color sheet based on the output voltage of the CCD line sensor whose storage time is adjusted by the storage time adjustment unit. Therefore, it is not necessary to mechanically drive the diaphragm part of the lens every time the color code of the color sheet changes to change the diaphragm, unlike the conventional device, which simplifies, downsizes, and reduces the weight of the device. Can be planned. Further, since a drive system for changing the aperture of the lens is not required, maintenance of the lens is facilitated and workability is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a color sheet appearance defect detection device according to the present invention.

FIG. 2 is a graph showing a relationship between a storage time of a CCD line sensor and an output voltage.

FIG. 3 is a graph showing a relationship between a storage time of a CCD line sensor and an output voltage.

FIG. 4 is a block diagram showing an electrical configuration of a conventional appearance defect detection device.

FIG. 5 is a schematic view showing a manufacturing process of a color sheet.

FIG. 6 is a cross-sectional view showing a portion where blurring occurs.

FIG. 7 is a cross-sectional view showing a portion where cissing occurs.

[Explanation of symbols]

 1 Light Source 2 CCD Line Sensor 4 Driving Section 5 Storage Time Adjustment Section 6 Sheet Color Setting Section 7 Appearance Defect Judgment Section 40 Color Sheet

Claims (1)

[Claims] 1. A device for detecting an appearance defect of a color sheet based on an output of an image pickup section using a CCD line sensor for receiving transmitted light or reflected light of light emitted from a light source to the color sheet, the sheet comprising: Based on the color signal output from the sheet color setting unit that outputs the color signal corresponding to the color of
An appearance defect detection device for a color sheet, comprising: an accumulation time adjustment unit that adjusts the accumulation time of the CCD line sensor.