JPH0797099A - Sheet color identifying device - Google Patents

Abstract

PURPOSE:To prevent the wrong selection or the like of a sheet by detecting the color of the sheet electrically to display it at a display part in the case of disposing a sheet tray, stored with colored sheets, at the paper supply part of an image forming device. CONSTITUTION:An optical device 10 disposed a paper supply part in correspondence with a sheet tray is provided with mechanism for radiating the light of a lamp 11 to a sheet P so as to detect the reflected light by two sensors 15, 16. Filters 17, 18 transmitting blue and red and disposed in relation to two sensors. Signals obtained by the respective sensors are inputted to a control device for processing. Three kinds of signals are outputted from the sensor 15 corresponding to the blue filter, and two kinds of signals are outputted from the sensor 16 corresponding to the red filter so as to obtain five kinds of sheet color detected information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for identifying a color of a sheet, and more particularly, when a colored sheet is stored in a sheet tray or the like attached to a sheet feeding section of an image forming apparatus, the sheet is colored. The present invention relates to a device that can automatically perform color identification.

[0002]

2. Description of the Related Art In an apparatus such as an electrophotographic copying machine or a printing machine, a colored paper may be used to characterize a copy or a printed matter. These colored papers are lightly colored so as not to affect the recorded image, and four types of colors, blue, green, yellow and pink are used. However, in an image forming apparatus equipped with a paper tray, the paper is stored in a sealed state in order to prevent moisture, dust, etc. from entering the paper stored in the paper tray from the outside. It is configured so that you cannot see the color of the paper from. Therefore, if you set colored paper in the paper feed section, make a copy, and then do not replace the paper,
When making a copy next, a problem such as an unnecessary colored copy is created, and it is necessary to take troublesome work such as retaking the copy.

In order to solve the above problems,
For example, each time an operator makes a copy, he or she may replace the colored paper, but in reality, many such mistakes occur. Also,
It has been attempted to eliminate copying mistakes by matching colored paper to specific ones of the paper trays that are installed in the paper feed section, but paper of unnecessary colors is installed. If so, problems such as retaking copies will not be resolved. As the colored paper used in the image forming apparatus, the colored paper of four colors and the white paper used for normal copying are targeted, as described above. The characteristics are shown in the graph of FIG. 7.

The example shown in the graph of FIG. 7 is intended for color paper sold by Fuji Xerox Co., Ltd. as standard paper. The horizontal axis represents wavelength (nm) and the vertical axis represents relative wavelength. When the reflection intensity (%) is taken,
It shows the reflection wavelengths and the relative reflection intensities of the yellow, pink (pink), blue, and green color papers. Therefore, when using the above-mentioned paper, if a device for discriminating the color of the paper is arranged for the paper tray so that the color type of the paper accommodated in the paper tray can be detected, the paper selection can be performed. You can prevent mistakes. However, in order to determine the color of the paper, it is necessary to provide a sensor for each color, which causes a problem that the configuration of the sensor and the determination circuit becomes complicated, and in order to accurately determine the colored paper, There arises a problem that it is not possible to sufficiently discriminate by using only the sensor corresponding to the color.

[0005]

An object of the present invention is to solve the above-described problem of distinguishing colored paper, and to provide a detecting means provided corresponding to the paper tray without directly visually judging the paper tray. The purpose of the present invention is to provide a device capable of discriminating the color of a sheet by using a device capable of discriminating four types of colored sheets using two types of filters, red and blue. It is intended to be provided.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a light source for irradiating a sheet contained in a sheet tray with light, two light receiving means for detecting light reflected from the surface of the sheet, and A filter that transmits light having different spectral characteristics is arranged for each of the light receiving means. A circuit for processing a detection signal is connected to each light receiving means, and a comparison circuit for separating at least one output signal of the two filters into three levels is provided to provide a sheet color identification device. Are configured.

In the sheet color identifying apparatus of the present invention configured as described above, the sheet is illuminated by the lamp 11 serving as a light source, and the reflected light is transmitted through the blue transmission filter and the red transmission filter, respectively. The detected light is detected by the sensor and input to the comparison circuit of the control device. Then, in the processing circuit of the control device, for example,
By outputting the blue signal as three kinds of signals and outputting the red signal as two kinds of signals, the output signals from the two sensors can be combined to determine the colored paper. Therefore, in the paper color identification apparatus of the present invention, it is possible to determine the colors of the five types of paper only by using the information of the light passed through the two types of sensors, and the detection result is used to form the image. By displaying it on the control panel of the apparatus, it is possible to easily determine the type of the sheet set in the sheet feeding unit of the image forming apparatus.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The sheet color identifying apparatus of the present invention will be described with reference to the illustrated example. In the optical device 10 shown in FIG. 1, a predetermined voltage is applied from a power source 12 to a lamp 11 arranged on the upper part of the paper tray to reflect the light of the lamp 11 on the paper P and receive light as two sensors. Means 1
A detection mechanism is constituted by 5 and 16. A blue transmission filter 17 is provided in the light receiving portions of the light receiving means 15 and 16.
And red transmission filter 18 are arranged, and the light passing through each filter is input to the sensor, and the sensor 15,
The signal obtained by 16 is transmitted to the control device as an electric signal. In the optical device 10, the lamp 11 as the light source can use any light emitting means, but in order to accurately detect the reflected light incident on the sensor, it is necessary to select one having a strong lamp light. The operation of processing the detection information can be easily performed.

In addition to the detection device shown in FIG. 1, a control device as shown in the circuit diagram of FIG. 2 can be provided. In the control device 20 shown in FIG. 2, the light receiving means 15 as a sensor for detecting the light passing through the blue transmission filter 17 has a current-voltage conversion circuit 21,
The voltage amplification circuit 22 and the comparison circuit 23 are connected to each other, and the current signal obtained by the sensor 15 is transmitted to the voltage amplification circuit 22 as a voltage V signal by the voltage-current conversion circuit 21.
In the voltage amplifier circuit 22, the voltage signal aV to which the signal of the gain a is applied is transmitted to the comparison circuit 23, and the blue signal is output as three kinds of signals 00, 01, and 11. The signal of the reflected light detected by the light receiving means 16 through the red transmission filter 18 is input to the comparison circuit 27 as the voltage bV through the voltage-current conversion circuit 25 and the voltage amplification circuit 26, and the signal is processed to 0, 1 2 types of signals are output.

The blue transmission filter 17 and the red transmission filter 18 arranged corresponding to the two sensors are filters having light transmission characteristics as shown in FIGS. 3 and 4, respectively. In the example shown in, the horizontal axis represents wavelength (nm) and the vertical axis represents relative transmittance (%). The blue transmission filter shown in the graph of FIG. 3 uses a type having a filter characteristic that maximizes the relative transmittance at the peak of 450 nm. Further, as the red transmission filter 18, a filter having the characteristics shown in the graph of FIG. 4 is used, and the relative transmittance increases between 600 and 650 nm, and the transmittance at wavelengths longer than that increases. It uses a constant type.

In the present invention, by combining the optical device shown in FIG. 1 with the control device shown in FIG. 2 and the filters shown in FIGS. Using the criteria shown in Figure 5,
The color of the colored paper is discriminated. In FIG. 5, the output of the sensor 15 for detecting the light transmitted through the blue transmission filter is such that the detection signal is output in the range of 400 to 500 nm.
The detection signal is output as 0. As for the output of the sensor 16, the detection signal is output as 1 at wavelengths exceeding 600 nm, and 0 is output at wavelengths below that. By the way, in the example shown in FIG.
The information detected in 5 is output as a signal (01) of intermediate strength, whereby the output of the sensor 15 is transmitted to the comparison circuit as three types of signals.

When the sensors 15 and 16 having the characteristics of the reception wavelength as described above are used and the paper types are yellow, pink, blue, green and white, the output signals of the two sensors are: Information is output according to the relative reflection intensities shown on the vertical axis of the graphs of the filters 17 and 18, respectively. Then, as shown in the relative reflection intensity of the paper obtained by combining the above two signals, the reflection intensity of each color is obtained as the reflection intensity of light for each frequency range according to each color, so in the control device, Information obtained by combining the information obtained from the two sensors can be input to a comparison circuit that processes two signals, and the type of colored paper can be determined. The judgment criteria for each color shown in the graph of FIG.
As shown in the diagram of FIG. 6, one sensor 16 has two
Type of signal (1, 0), the other blue transmission filter 1
If the signals passing through 7 and detected by the sensor 15 are set to three types (00, 01, 11), the operation of discriminating the colored paper can be accurately performed.

Of course, in the above-described embodiment of the present invention, when each type of colored paper has a wavelength reflection characteristic as shown in FIG. 7, the colored paper is used. It is possible to specify the type of paper included in. On the other hand, in the colored paper, if each kind of color has a reflection characteristic for a wavelength different from that in FIG. 7, the light receiving characteristic of the filter shown in FIGS. , 6 may be slightly changed to judge the color of the paper. Furthermore, in the case of using a paper colored with another color other than the above four colors, three types of signal output circuits are configured for each of the two filters to make a judgment based on more information. It is also possible to do.

In the device of the present invention which outputs the above-mentioned signal, the type of the colored paper can be displayed on the display part such as the control panel by using the signal obtained from the control device. Then, the operator can easily discriminate the paper type by looking at the display information of the colored paper type displayed on the display unit of the image forming apparatus. Although any lamp can be used as the light source of the optical device 10 of the present invention, in order to allow the sensor to accurately detect the light passing through the filter, a lamp that emits relatively strong light is used. Can be used to improve the rate of detection. Further, the optical device of the present invention can be installed in all of a plurality of paper trays arranged in the paper feed unit, but in order to simplify the device, one of the plurality of paper trays arranged in the paper feed unit is to be installed. A mechanism for detecting the color of the paper can be provided only for the paper tray intended for the colored paper so that the colored paper can be accommodated, and the operator's burden can be reduced. .

[0015]

Since the sheet color identification apparatus of the present invention has the above-mentioned configuration, when a lightly colored sheet is attached to the sheet feeding section of the image forming apparatus, the type of the sheet is selected. It can be automatically identified and displayed on the control panel. Further, since the optical device of the present invention is provided with only two types of filters and a detection light processing circuit by the sensor, the control mechanism does not need to be complicated and can be easily incorporated in the paper feeding unit. Further, in the optical device of the present invention, one sensor outputs a 1-bit signal, and the other sensor outputs a 2-bit signal. Based on the two types of signals. Since it is possible to determine the colors of the five types of paper, it is possible to easily perform the signal processing, and it is possible to easily perform the operation of determining the colored paper accommodated in a state where it cannot be directly viewed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an optical device of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a control device of the present invention.

FIG. 3 is a graph showing a wavelength and a relative transmittance of light in a blue transmission filter.

FIG. 4 is a graph showing wavelength and relative transmittance of light in a red transmission filter.

FIG. 5 is a graph showing a state of determination of colored paper by the device of the present invention.

FIG. 6 is a chart showing numerical values of the state shown in FIG.

FIG. 7 is a graph showing the light reflection characteristics of a colored paper targeted by the present invention.

[Explanation of symbols]

10 optical device, 11 lamp, 12 power supply, 15/16 light receiving means, 17, 18 filter, 20 control device, 21/25 current-voltage conversion circuit, 22/26 voltage amplification circuit, 23/27
Comparison circuit.

Claims (1)

[Claims] 1. A light source for irradiating a paper stored in a paper tray with light, two light receiving means for detecting light reflected from the surface of the paper, and a spectrum for each of the light receiving means. A filter for transmitting light having different characteristics is arranged, a circuit for processing a detection signal is connected to each light receiving means, and at least one output signal of the two filters is divided into three levels. A color identification device for paper, characterized in that a comparison circuit is provided.