JPH07152853A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the deciding accuracy of an image forming device by decreasing the wrong deciding frequency caused by the visible light. CONSTITUTION:This image forming device contains a mechanism which detects a special original using the ink that absorbs the infrared rays. Then the image forming device is provided with a halogen lamp 102 which irradiates the light on the original, a lamp driving part 104, i.e., a color temperature changing means which changes the color temperature of the lamp 102, and a system controller 114 which controls the pert 104 to lower the color temperature of the lamp 102 when the special original is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a function of discriminating special documents such as banknotes and securities, and more particularly to a special document using ink that absorbs infrared rays and / or ultraviolet rays. The present invention relates to an image forming apparatus having a mechanism for detecting

[0002]

2. Description of the Related Art In recent years, due to improvements in image processing technology and image forming technology, it has become possible to perform image formation so finely that copy bills copied by a color copying machine and actual bills cannot be easily distinguished. For this reason, a device has been developed that determines special documents such as bills and securities, and prohibits illegal copying in the case of special documents. An image forming apparatus equipped with a function of determining a special document in a copying machine. Is also provided.

In such an image forming apparatus, as a method for determining a special document, for example, a method using a pattern matching method as disclosed in Japanese Patent Laid-Open No. 2-83571 "Image recording apparatus" is generally used. In this apparatus, it is determined whether the original is a special original based on the input image data and the pattern data registered in advance.

On the other hand, even in the case of special manuscripts such as banknotes and securities, in order to make it easy to determine that they are ordinary manuscripts (manuscripts that are not special manuscripts), they absorb light in the invisible light region such as infrared rays and ultraviolet rays. A special document on which an image pattern for determination is formed has been developed. In response to this, an image forming apparatus having a mechanism for detecting a special document using ink that absorbs infrared rays and / or ultraviolet rays is also provided.

[0005]

However, according to the conventional image forming apparatus having a mechanism for detecting a special document using ink that absorbs infrared rays and / or ultraviolet rays, the image information in the visible light region is read. The light source is used to illuminate the original, and the reflected light is divided into visible light and infrared light, or visible light and ultraviolet light by a filter, and infrared image information or ultraviolet image information is read, but Since light energy occupies most of the light, the S / N ratio is poor, and erroneous determination occurs due to the influence of visible light, and the determination accuracy is not always good.

The present invention has been made in view of the above, and an object thereof is to reduce erroneous determination due to visible light and improve determination accuracy.

[0007]

In order to achieve the above-mentioned object, the present invention is an image forming apparatus having a mechanism for detecting a special document using ink that absorbs infrared rays, and a light source for irradiating the document with light. Means, color temperature changing means for changing the color temperature of the light source means, and control means for controlling the color temperature of the light source means via the color temperature changing means when detecting the special document. An image forming apparatus including the above is provided.

The color temperature changing means changes the color temperature by changing the voltage applied to the light source means.

In order to achieve the above object, the present invention provides an image forming apparatus having a mechanism for detecting a special document using ink that absorbs ultraviolet rays, when reading image information in the visible light region from the document. And a second light source means used when reading image information in the ultraviolet region from a document, and when the special document is detected, the first light source is turned off. An image forming apparatus provided with a light source control unit for turning on the second light source.

The second light source is a cold cathode tube.

[0011]

In the image forming apparatus of the present invention (claims 1 and 2), when the special original is detected, the control means changes the applied voltage of the light source means through the color temperature changing means to change the color of the light source means. By lowering the temperature, the generation ratio of visible light and infrared rays changes, and image information is read by infrared rays in a situation where the S / N ratio is good.

An image forming apparatus of the present invention (claim 3,
In 4), when detecting a special document, the first light source used when reading image information in the visible light region from the document is turned off by the control of the light source control means, and image information in the ultraviolet region from the document is turned off. By turning on the cold cathode fluorescent lamp (second light source) used for reading, the cold cathode fluorescent lamp emits ultraviolet rays, and the image information is read by the ultraviolet rays in a situation with a good S / N ratio.

[0013]

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

FIG. 1 is a block diagram of the image forming apparatus according to this embodiment, in which a halogen lamp 102 which is a first light source means used when reading image information in a visible light region from a document 101 and a document 101. A cold cathode tube 103 which is a second light source means used when reading image information in the ultraviolet region from the halogen lamp 102 and the cold cathode tube 103.
Lamp driving unit 104 for driving the light source, an infrared detection filter 105a for detecting light in the infrared region, a visible light filter 105b for detecting visible light, and an ultraviolet filter for detecting light in the ultraviolet region. 105c
A filter 105 having three switchable optical filters, and a filter driving unit 106 that moves the filter 105 up and down to switch between the infrared detection filter 105a, the visible light filter 105b, and the ultraviolet light filter 105c. , The reflected light from the original 101 that has passed through the filter 105 is received, photoelectric conversion is performed, and R,
CCD 107 for generating G and B image data, and CCD
An A / D converter 108 for converting the image data (analog signal) from 107 into a digital signal, a shading correction circuit 109 for performing shading correction, and R, G, B image data after shading correction are input. Then, various image processing such as color conversion processing and gradation processing is performed, and Y, M, C
Image processing circuit 110 for sending as image data of R, G, and B image data after shading correction, and a special manuscript judgment unit 111 for judging whether manuscript 101 is a special manuscript or not. An output prohibition circuit 112 that prohibits the output of image data sent from the image processing circuit 110 based on an output prohibition signal of a special document determination unit 111 described later.
And a printer unit 1 that forms an image on a recording sheet in accordance with Y, M, and C image data input from the image processing circuit 110.
13 and a system controller 11 for controlling each of the above parts
4 and.

FIG. 2 shows the configuration of the optical system of the image forming apparatus of this embodiment. As shown in the figure, a halogen lamp 102 and a cold cathode tube 103 are arranged. Halogen lamp 1
02 or the light emitted from the cold cathode tube 103 is reflected by the original 101 placed on the contact glass 201, and the reflected light is reflected by the mirrors 202, 203, 204.
Then, it is guided to the CCD 107 by the lens 205 and input as image data. At this time, the reflected light is reflected by the filter 1 arranged between the lens 205 and the CCD 107.
When reading visible light by passing through 05,
Light in unnecessary areas is removed depending on whether the infrared rays or the ultraviolet rays are read. Note that the filter 105 is moved up and down as needed by the filter driving unit 106 so that any one of the infrared detection filter 105a, the visible light filter 105b, and the ultraviolet filter 105c has a corresponding C
It is arranged in the optical path in front of the CD 107.

The operation of the above configuration will be described. In the present embodiment, two prescans are performed before reading image data with visible light, and image data in the infrared region is read during the first prescan,
The special document determination unit 111 determines whether the document is a special document, the image data in the ultraviolet region is read during the second prescan, and the special document determination unit 111 determines whether the document is a special document. I shall.

First, at the time of the first prescan, the system controller 114 controls the lamp driving unit 104 to turn on the halogen lamp 102 by dropping it from the rated voltage to about 70%, and at the same time controls the filter driving unit 106. The filter 105 is moved to switch to the infrared detection filter 105a to perform scanning, and the CCD 107
Read the image data with.

The image data read by the CCD 107 is input to the special document determination section 111 via the A / D converter 108 and the shading correction circuit 109.
The special manuscript judgment unit 111 compares the input image data with the judgment pattern of the special manuscript stored in advance by pattern matching and reads the read manuscript 101.
It is determined whether the document is a special document. If it is determined that the document is a special document, a copy inhibition signal is output to the output inhibition circuit 1
12 and the system controller 114.

FIG. 3 shows the power consumption (lamp voltage) and CCD
The output relationship is shown. As shown in the figure, the change in CCD output with respect to the voltage change resolved into RGB has less attenuation in the R component near the infrared region than in the G component as the lamp voltage decreases, and It can be expected that the temperature will change significantly. When the voltage of the halogen lamp 102 is lowered in this way, the color temperature is lowered, so that the energy in the visible light region becomes larger than the energy in the infrared region. Therefore, by lowering the color temperature, infrared imaging (image reading by the CCD 107) can be performed in a situation with a good S / N ratio.

As described above, the special manuscript judgment section 111 reduces the color temperature by lowering the halogen lamp 102 to about 70% from the rated voltage, and uses the image data read in a good S / N ratio. Since it is determined whether the document is a special document, erroneous determination due to visible light is reduced and the determination accuracy is improved.

Next, during the second prescan, the system controller 114 controls the lamp driving unit 104 to turn off the halogen lamp 102, turn on the cold cathode tube 103, and at the same time control the filter driving unit 106. The filter 105 by moving the
Switching to c, scanning is performed, and image data is read by the CCD 107.

The image data read by the CCD 107 is input to the special document determination section 111 via the A / D converter 108 and the shading correction circuit 109.
The special manuscript judgment unit 111 compares the input image data with the judgment pattern of the special manuscript stored in advance by pattern matching and reads the read manuscript 101.
It is determined whether the document is a special document. If it is determined that the document is a special document, a copy inhibition signal is output to the output inhibition circuit 1
12 and the system controller 114.

Here, the cold cathode tube 103 that emits ultraviolet rays is used as a light source, and the image pickup by the ultraviolet rays (CCD 10
7) is performed, it is possible to determine whether the document is a special document by using the image data read in a situation where the S / N ratio is good, and erroneous determination due to visible light is reduced. Judgment accuracy is improved.

Further, the cold cathode tube 103 has an advantage that the tube diameter is thin and the effect of focusing by the reflecting plate is great.

After that, in order to read an image with normal visible light, the cold cathode tube 103 is turned off, the halogen lamp 102 is turned on at a normal rated voltage, and the filter 105 is switched to the visible light filter 105b. Scan is executed to obtain R, G, B image data.

As described above, in the present embodiment, even when the image in the infrared region or the ultraviolet region is read, the S / N
Since the image data can be input in a good ratio, erroneous determination due to visible light can be reduced and the determination accuracy can be improved.

In the case of infrared rays and ultraviolet rays,
Although it is less than ordinary visible light energy, patterns that use ink that absorbs infrared rays or ultraviolet rays that are formed on special documents such as banknotes are often simple patterns, and complicated patterns such as letters Therefore, the above method can sufficiently improve the discrimination accuracy.

In the above embodiment, the case where the image in the infrared region and the image in the ultraviolet region is read by performing the prescan twice is taken as an example. However, the present invention is not limited to this, and in general, It is also possible to perform only one or the other and add the other one as needed. Further, it is needless to say that the present invention can be applied to an image forming apparatus that only determines a special document in the infrared region and an image forming apparatus that only determines a special document in the ultraviolet region.

[0029]

As described above, the image forming apparatus of the present invention is an image forming apparatus having a mechanism for detecting a special document using ink that absorbs infrared rays, and a light source means for irradiating the document with light. , A color temperature changing means for changing the color temperature of the light source means, and when detecting the special document,
Since the control means for controlling the color temperature of the light source means is provided via the color temperature changing means, it is possible to reduce erroneous determination due to visible light and improve the determination accuracy.

The image forming apparatus of the present invention is used for reading image information in the visible light region from an original in an image forming apparatus having a mechanism for detecting a special original using ink that absorbs ultraviolet rays. One light source means, a second light source means used when reading image information in an ultraviolet region from a document, and the first light source means when detecting the special document.
And a light source control means for turning on the second light source, reducing erroneous determination due to visible light.
The determination accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an image forming apparatus of this embodiment.

FIG. 2 is an explanatory diagram showing a configuration of an optical system of the image forming apparatus of this embodiment.

FIG. 3 is an explanatory diagram showing a relationship between power consumption (lamp voltage) and CCD output.

[Explanation of symbols]

 102 Halogen Lamp 103 Cold Cathode Tube 104 Lamp Drive Unit 105 Filter 105a Infrared Detection Filter 105b Visible Light Filter 105c Ultraviolet Filter 106 Filter Drive Unit 107 CCD 111 Special Document Judgment Unit 114 System Controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Midori Aida 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Takatsugu Saito 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh

Claims (4)

[Claims] 1. An image forming apparatus having a mechanism for detecting a special document using ink that absorbs infrared rays, and a light source unit for irradiating the document with light and a color temperature changing unit for changing the color temperature of the light source unit. An image forming apparatus comprising: a control unit that controls the color temperature of the light source unit via the color temperature changing unit when the special document is detected. 2. The image forming apparatus according to claim 1, wherein the color temperature changing unit changes the color temperature by changing the voltage applied to the light source unit. 3. An image forming apparatus having a mechanism for detecting a special manuscript using ink that absorbs ultraviolet rays, and a first light source means used when reading image information in a visible light region from the manuscript; Second light source means used when reading image information in the ultraviolet region, and light source control means that turns off the first light source and turns on the second light source when detecting the special document. An image forming apparatus comprising: 4. The image forming apparatus according to claim 3, wherein the second light source is a cold cathode tube.