JPH04362969A - Copying machine provided with color sensor - Google Patents

Abstract

PURPOSE:To prevent a detecting error from occurring by discriminating colors of both sides and deciding whether a paper is a colored paper or a white paper based on the result. CONSTITUTION:Color sensors DWS1-DWS4 are arranged on the lower side of an original carrying path, and opposed to an upper resist roller 22d through the original carrying path. The upper resist roller 22d is colored in a specified color. The coloring is for discriminating whether the color sensors DWS1-DWS4 detect the upper resist roller 22d or an original; they discriminate that the original is detected when they detect a color other than the color of the upper resist roller 22d. The color sensors DWS1-DWS4 detect the color of the surface of the original. And the color sensor DWS5 is arranged above the original carrying path, and detects the color of the back surface of the original.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a full-color copying machine capable of reproducing the colors of an original as they are.

0002

2. Description of the Related Art In recent years, full-color copying machines that can reproduce original colors as they are have become popular.

This full-color copying machine scans the original image three times, and in the first scanning, the reflected light from the original is guided to the photoreceptor through a blue filter, and a blue color is applied to the formed latent image. Attach yellow toner, which is a complementary color. Then, in the second scanning of the original, magenta toner is applied to the latent image formed through the green filter, and in the third scanning of the original, magenta toner is applied to the latent image formed through the red filter. to apply cyan toner. These three colors of toner are superimposed on a transfer belt placed adjacent to the photoreceptor, and transferred to paper to form a full-color image.

[0004]Moreover, recent copying machines include an automatic document feeder that is equipped with a document tray on which originals to be copied are placed, and that automatically feeds the originals placed on the document tray one by one to the document tray. There are some that are equipped with (ADF). A document size sensor is provided on the document table to detect the width and length of the document placed thereon. FIG. 8 is a diagram showing a conventional document placement table. On the document placement table 81 are sensors (microswitches, optical sensors, etc.) 82 to 85 for detecting the width of the document, and sensors 82 to 85 for detecting the length of the document. Sensors 86 and 87 for detection are arranged.

[0005]

[Problems to be Solved by the Invention] The above-mentioned full-color copying machine has the advantage of being able to reproduce the colors of the original as is, but on the other hand, when copying an original on which an image is formed on colored paper, the color of the colored paper cannot be reproduced. There is a problem in that even images are reproduced, resulting in a copy image that is extremely difficult to see.

[0006] When the user forgets that the original is a colored paper original and tries to make a full-color copy, or when a colored paper original is mixed in with a white original, the above-mentioned hard-to-read copy image may be formed.

Further, the document size sensors 82 to 85 and 86, 87 provided in the conventional ADF were only for detecting the document size, but they do not only have a single function but also detect the document size. In addition to this, it is preferable to have other functions as well.

[0008] An object of the present invention is to provide a color sensor in which (1) the sensor for detecting the size of the document also has other functions; The object of the present invention is to provide a copying machine with the following features.

[0009]

Means for Solving the Problems The invention according to claim 1 of this application provides a color sensor for identifying the color of the front side of a document to be copied, a color sensor for identifying the color of the back side of the document, and a color sensor for identifying the color of the back side of the document to be copied. When the front and back sides of are the same color other than white,
The present invention is characterized by providing a means for notifying a colored paper manuscript.

[0010] The invention according to claim 2 of this application is a copying machine equipped with a document table on which a document to be copied is placed and the placed document is fed to a document table. A plurality of color sensors for identification or color sensors for identifying the color of the back side are arranged in a direction perpendicular to the feeding direction of the original, and a means for detecting the width of the original based on the output state of the plurality of color sensors is provided. It is characterized by having been established.

[0011]

[Operation] In the invention according to claim 1 of this application, when the front side color and the back side color of the document are both non-white and the same color, it is determined that the document is a colored paper document and a notification is made. ing. In this way, since the colors of both the front and back sides are identified and the result is used to determine whether the paper is colored or white, detection errors are prevented from occurring. If the original is a colored paper document, this is notified, and full-color copying can be stopped based on this notification.

In the invention according to claim 2 of this application, each of the plurality of color sensors arranged in a direction orthogonal to the feeding direction of the original on the original placing table detects the presence or absence of the original. As for the color sensors, if the width of the document becomes wide, the sensors arranged on the outside will also turn on, but if the width of the document is narrow, the color sensors on the outside will not turn on and only the color sensors on the inside will turn on. Therefore, the width of the document can be detected based on the on state of the color sensor.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a front view showing the structure of a full-color copying machine.

A document table 1 made of transparent hard glass is provided on the top surface of the copying machine main body.

An ADF 2 is provided above the document table 1. The ADF 2 feeds the originals placed on the original platen 21 one by one from the top to the original platen 1.
This device discharges the upper document onto the document discharge tray 26. FIG. 5 shows the structure of the paper feeding section 22 that feeds the original on the original placing table 21 to the original placing table 1. As shown in FIG. The paper feed section 22 is equipped with a take-up roller 22a, a feed roller 22b, and a registration roller 22c. A stack of originals to be copied is placed on the original placing table 21 with the image side facing down. The take-up roller 22a takes up the uppermost one of the documents placed on the document table 21 and feeds it toward the feed roller 22b.

[0016] This document is transferred to feed rollers 22b and 22c.
After that, the original platen 1 is moved by registration rollers 22d and 22e.
(See Figure 2). A color sensor is arranged in the paper feed section 22, as will be described later, and a size detection sensor is arranged in the document mounting table 21.

A conveyance belt 23 and discharge rollers 24 and 25 are provided above the document table 1. A document fed from the paper feed section 22 is conveyed by a conveyor belt 23 above the document table 1 and stopped at a predetermined position. At that position, the original is scanned by the optical system 3 below the original table 1, and the reflected light is guided to the photoreceptor 4. After scanning the original, the original is ejected to the original ejection tray 26 by the conveyance belt 23 and ejection rollers 24 and 25.

Color sensors DWS1 to DWS5 for detecting the color of the document are arranged above and below the document conveyance path in the paper feed section 22. For example, a semiconductor color sensor PD152 manufactured by Sharp is used as the color sensor. A semiconductor color sensor is an element in which two photodiodes are vertically integrated into one substrate. When light is irradiated onto this semiconductor color sensor, most of the short wavelength light is absorbed by the photodiode on the surface side, so there is not much absorption by the photodiode on the deep side, but in the case of long wavelength light, it is absorbed by the photodiode on the surface side. It passes through the side photodiodes without much absorption, and most of it is absorbed by the deeper photodiodes. Therefore, when light of one wavelength is made incident on the semiconductor color sensor, the two photodiodes exhibit different sensitivities. FIG. 4A is a block diagram of an example of a signal processing circuit of a semiconductor color sensor. Short circuit current ISC1, I obtained from photodiodes PD1, PD2
SC2 is each logarithmically compressed, and then a subtracted voltage V0 is outputted by a subtraction circuit. FIG. 4(B) shows the relationship between the incident wavelength and the output voltage V0, and the output voltage value V0 changes depending on the incident wavelength. therefore,
When a semiconductor color sensor detects reflected light from an original, when the original is white, the output voltage of the semiconductor color sensor is approximately the same voltage value as when the light from the sensor's light source is directly incident. However, when the original is colored paper, a specific wavelength of the light source light is reflected depending on the color, so the output voltage value changes depending on the color of the colored paper. This allows the color of the original to be identified.

Color sensors DWS1 to DWS4 are arranged below the document conveyance path and face the upper registration roller 22d via the document conveyance path. Upper registration roller 22d
is colored in a predetermined color. This is color sensor D
This coloring is used to determine whether WS1 to DWS4 are detecting the upper registration roller 22d or a document, and if a color other than the color of the upper registration roller 22d is detected, it is in the document detection state. It is determined that Color sensors DWS1 to DWS4 detect the color of the front surface of the document. Further, the color sensor DWS5 is arranged above the document transport path and detects the color of the back side of the document.

The lower color sensors DWS1 to DWS4 are arranged in a direction perpendicular to the document feeding direction (arrow direction in the figure). Figure 6 shows color sensors DWS1 to DWS.
5 is a diagram showing the arrangement state of No. 5. Lower color sensor D
WS1 to DWS4 are the standard original sizes (B5, A
4 etc.) is placed at a position corresponding to the width. The width of the document can be recognized by determining which of the color sensors DWS1 to DWS4 is on and which sensor is off. In addition, as shown in FIG. 6, a size detection switch (micro switch, etc.)
, DLS2 are arranged. Size detection switch DL
S1 and DLS2 are arranged at positions corresponding to the length of the specified size, and recognize the length of the document. In this way, the size of the document is determined by detecting the width and length of the document using the sensor. FIG. 7 is a diagram showing the relationship between the detection state of the sensor and the document size. For example, if DWS2 detects a document but DWS1, DWS3, DWS4, and DLS1 do not detect the document, it is determined that the document size is B5. Note that in this case, the detection state of DLS2 is not taken into consideration.

The optical system 3 includes a copy lamp 31, reflective mirrors 32 to 36, a lens 37, and a color separation filter 38. The original set on the original platen 1 is exposed to light by the copy lamp 31, and the reflected light is reflected by the mirrors 32 to 3.
6, a lens 37, and a color separation filter 38 before being guided to the photoreceptor 4. The color separation filter 38 includes three types of filters that transmit blue, green, and red light, and these filters are inserted into the optical path of reflected light from the document as necessary, such as during full-color copying.

A charger 41 is installed around the belt-shaped photoreceptor 4.
, blank lamp 42, developing devices 43y, 43m, 43c
, 43b, transfer belt 5, cleaner 44, and static eliminator 45 are arranged in this order. Developer 43y, 43m, 43
C and 43b store toners colored yellow, magenta, cyan, and black, respectively. Paper cassettes 61 and 62 are removably attached to the right side of the copying machine main body. Paper cassettes 61 and 62 store paper of different sizes, and the paper is fed from either cassette during image formation. A secondary transfer roller 51 is provided below the transfer belt 5. Secondary transfer roller 5
1 is provided so as to be movable up and down, and moves upward so as to come into contact with the transfer belt 5, as shown by the two-dot chain line in the figure, only when transferring the toner image onto the paper. The fixing device 7 includes a fixing roller 71 consisting of a pair of rollers at the lower left inside the copying machine main body. A heater (not shown) is provided inside the upper roller 71a of the fixing roller 71, and the surface of the upper roller 71 is heated to a temperature of approximately 180°C. On the left side of the copying machine body, there is a paper ejection tray 7 from which the paper on which the image has been formed is ejected.
is provided.

In the copying machine constructed as described above, toner image formation on the photoreceptor 4 is performed almost in the same manner as in a normal copying machine. However, when forming a latent image, a color separation filter 38 is used as necessary, and when forming a toner image, toner is supplied from one of the four types of developing devices.

When forming a monochromatic image, a latent image is formed without a filter, and one of the developing devices 43y, 4
3m, 43c, and 43b toners are supplied to form a monochromatic toner image on the photoreceptor 4. This toner image is transferred to the transfer belt 5, and then transferred by the secondary transfer roller 51 to paper fed from the paper cassette 61 or 62. The toner image transferred onto the paper is heated by the fixing device 7, and the toner on the surface is softened and melted, and then fixed onto the paper. Thereafter, the fixed paper is discharged to a paper discharge tray 8 on the left side of the copying machine main body.

Further, when forming a full color image, the following processing is performed. As shown in the prior art section, the methods of color separation of reflected light from the document by a color separation filter and toner supply by a developing device when forming a full-color image are as follows.
For example, when the light reflected from the original passes through a blue filter and is irradiated onto the photoreceptor, yellow toner is deposited on the photoreceptor by the developing device 43y. This yellow toner image is transferred to the transfer belt 5.

Next, a magenta toner image is formed on the photoreceptor 4, and this toner image is transferred so as to overlap the magenta toner image on the transfer belt 4. Furthermore, a cyan toner image is formed on the photoreceptor, and is transferred so as to overlap the yellow and magenta toner images on the transfer belt. While the three-color toner images are being transferred to the transfer belt 5, the secondary transfer roller 51 is separated from the transfer belt 5. After the three-color toner images are superimposed on the transfer belt 5, the secondary transfer roller 51 moves upward, and paper is fed from either the paper cassette 61 or 62, and the three-color toner image is are superimposed and transferred to paper. The subsequent processing is the same as when forming a monochrome image, and the sheet is discharged to the paper discharge tray 8 after the fixing process.

FIG. 3 is a block diagram of the control section of the copying machine.

The CPU 11 controls the entire copying machine according to a program stored in the ROM 12. RAM13
is the work area used during this processing. CPU
The detection results of the color sensors DWS1 to DWS5 and the size detection switches DLS1 and DLS2 are input to 11. The RAM 13 is provided with a memory area for temporarily storing the detection results. The size of the document is detected based on the stored detection results, and it is determined whether the document is a white document or a colored paper document, as will be described later. On the other hand, an operation panel 14 is provided on the top surface of the copying machine main body. The operation panel 14 is provided with a key 14a for selecting a full color copy mode, keys 14b to 14e for selecting a copy color in a monochrome color mode, a colored paper original display section 14f for displaying that the copied original is a colored paper original, etc. There is.

[0029] The process of determining colored paper originals in the copying machine configured as described above will be explained. FIG. 1 is a flowchart showing the processing procedure.

First, when paper feeding processing is started in the full color copy mode, the detection result from the color sensor DWS5 that detects the color on the back side of the original is determined (n1→n2→
n3). If the detection result of the DWS5 indicates a white original, copy processing begins; however, if it is determined that the original is not white, the detection result of the back side color sensor DWS5 and the front side color sensor DWS1 are used. ~3DWS4 is compared with the output result of one of the sensors that detected the document (n4). As a result, if the two almost match, the color on the front side is the same as the color on the back side, so it is determined that the original is colored paper. Display that it is good (n5)
. On the other hand, if the color on the back side of the document does not match the color on the front side, full-color copy processing is directly performed. After displaying that the original is colored paper, mode switching, etc. is accepted, and if the print switch is operated, the copying process is started (n6→n7).

[0031] In this example, when it is determined that the original is colored paper, it is displayed as colored paper. ). Further, in this embodiment, from the document placement table 21 to the document table 1
A color sensor is placed in the feeding path that feeds the document to the document table 1 to detect the color of the document being fed.
A color sensor may be provided near the document table 1, for example, on the lower surface of the document table and the original cover, to detect the color of the document set at a predetermined position on the document table 1. Even in this case, by arranging a plurality of color sensors on the lower side, it is possible to detect the color of the document and the size of the document at the same time.

[0032]

According to the present invention, when it is determined that the original is colored paper, a message to that effect is displayed.

[0033] This prevents, for example, if a mistake is made in setting the mode or if a colored paper original is mixed into the continuous copy original, full-color copying is performed without realizing it, resulting in a copy that is difficult to read. There are advantages that can be achieved.

Furthermore, the color sensor for detecting the color of the document also detects the width of the document at the same time, thus having two functions. That is, there is an advantage that the color sensor can be used effectively.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the processing procedure for discriminating colored paper originals in a copying machine according to an embodiment of the present invention.

[Figure 2] Schematic configuration diagram of the copying machine

[Figure 3] Block diagram of the control unit of the copying machine

[Figure 4] (A)
is a block diagram of an example of the signal processing circuit of the semiconductor color sensor used in this device, and (B) is a diagram showing the relationship between the input wavelength and output voltage to the sensor.

[Figure 5] Diagram showing the configuration of the paper feed section of the ADF

[Figure 6] Diagram showing the arrangement of color sensors

[Figure 7] Diagram showing the relationship between sensor detection status and document size

[Figure 8] Diagram showing the arrangement of conventional document size detection sensors

[Explanation of symbols]

1 Manuscript table 2 ADF DWS1~DWS5 Color sensor

Claims (2)

[Claims] 1. A color sensor that identifies the color of the front side of a document to be copied; a color sensor that identifies the color of the back side of the document; and a color sensor that identifies the color of the back side of the document; A copying machine equipped with a color sensor, characterized in that the copying machine is provided with means for notifying a document. 2. A copying machine equipped with a document tray on which an original to be copied is placed and the loaded document is fed to the document tray, which includes a color sensor that identifies the color of the front surface or a color sensor that detects the color of the back surface. A color sensor characterized in that a plurality of color sensors for identification are arranged in a direction perpendicular to the feeding direction of the document, and a means for detecting the width of the document based on the output state of the plurality of color sensors is provided. Copying machine equipped with