JPH01200372A - Image forming device - Google Patents

Abstract

PURPOSE:To perform color detection without raising a cost by performing color recognition based on first color information read out from a storing means and based on second color information sampled out from a color sampling means during scanning when double-acting is performed. CONSTITUTION:A switchable red filter 55 is provided in front of a lens 51. A CPU 64 (a color recognizing means) performs the color recognition which recognizes color based on the color information of blue read out from an RAM 65 as a storing means, and based on the color information of red sample from the RAM 65 during scanning when the double-acting is performed, and the color information obtained from the color recognition is written in the RAM 65. Thus, the storing means 65 which stores color image information is simplified and the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that scans a document during forward and backward movement of a scanning optical system.

(Background of the Invention) A method for reading color information in a document image is to read it without applying a color filter when the scanning optical system moves forward, store the resulting read data in a page memory, and then apply a color filter when it moves backward. The document image is read, the resulting read data is stored in a separate page memory, and after the scanning optical system completes the backward movement, the read data obtained when moving forward and backward is compared based on the image tip sensor detection position. It has been proposed to detect the

In addition, a sensor is provided outside the document scanning area, and the OF of the scanning optical system is
! There have also been proposals that detect colors by collating the read data obtained when moving forward and backward.

[Problem that the invention seeks to solve]

□However, in this method, one page memory is provided to store the read data obtained when the scanning optical system moves forward, and one page memory is provided to store the read data obtained when the scanning optical system moves backward, so the total number of page memories is 2. There is a problem that cost reduction is hindered by these page memories.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus that can perform color detection without increasing costs.

(Means for Solving the Problems) An image forming apparatus according to the present invention includes a scanning unit that optically scans an original document during forward movement and a backward movement, and a scanning unit that optically scans an original document during forward movement and a first scanning unit during forward movement. an image forming apparatus, the image forming apparatus having a color extraction means for extracting a second color by scanning during backward movement, and a storage means for storing information about the first color;
The first data read from the storage means during scanning during backward movement.
and color recognition means for performing color recognition based on the color information extracted by the color extraction means and the second color information extracted by the color extraction means.

(Operation) The image forming apparatus according to the present invention, during scanning during backward movement,
Color information is obtained by the color information processing means based on the first color information read from the storage means and the second color information extracted by the color extraction means.

〔Example〕

1 to 4 show an embodiment of the present invention.

51 is a charge-coupled device 52 lens, 52 is a charge-coupled device (hereinafter referred to as CCD), and 53 and 54 are C from the light source 16 (the illuminated part of J'I81 in FIG. 2).
This is the optical path reaching the CD 52 and the photoreceptor 6 shown in FIG. 3, and a portion thereof. A switchable red filter 55 and blue filter 59 are provided in front of the lens 51, and can be switched as necessary, as will be described later. The home position sensor S0 detects that the scanning optical system 3a is at the document scanning start position, and the rear end sensor S2 detects that the scanning optical system 3a is outside the document scanning area. In addition, the image tip sensor SI detects the tip of the image. CPU (c
The internal processing unit (color recognition means) 64 performs color recognition based on the blue color information read out from the RAM 65 and the red color information extracted during scanning during backward movement, and also performs color recognition on the basis of color information of the blue color read out from the RAM 65 and the red color information extracted. This is written into the RAM 65. Further, when the trailing edge of the document is detected during forward scanning, the CCD 52
The reading of image information is stopped, and the reading of image information is started again when it is detected during backward scanning. Further, the CPU 64 reverses the rotational direction of the scan motor 73 via the motor driver 72 when the trailing edge of the document is detected during backward scanning.

The scan generator 73 adopts a slow-up method at the time of rising and a slow-down method at the time of rising, and the rising and falling rotation angles are managed by the CPU 64,
When stopped, it is energized and the stopped position is maintained. The solenoid SL applies a filter 55 when the trailing edge of the document is detected during forward scanning, and applies a blue filter 59 after stopping at the home position during backward scanning.

A large number of LEDs 50 are arranged in the axial direction so that they can illuminate the next position slightly distant from the image forming position of the original image on the photoreceptor 6 shown in FIG. A program for controlling the copying machine M is recorded in the ROM 66.

The original H40 placed on the original table glass 2 is placed on the original platen 70.
The original pressing plate 70 changes its inner color to yellow.

FIG. 2 shows a copying machine. As shown in the figure, the copying machine M that performs double-sided copying and multiple copying of this embodiment has a copying section 54 equipped with a photoreceptor 6 approximately in the center of the main body, and a document table 2 on the upper part of the main body. It is equipped with A scanning optical system (scanning means) 3a and a light detection means 3b for detecting document information (size, color, AE value) are provided below the document table 2, and on the right side of the machine. Sheet feeding section 1 consisting of a sheet cassette 7.9 and manual feed stand 10
1, and the manual feed stand 10 and sheet cassette 7.9 each have paper feed rollers 12.13.1.
5 is a provision.

The light reflected from the original image on the original platen 2 illuminated by the light source 16 is changed in direction by +m scanning optics, %3a, transmitted through the imaging lens 17, and is exposed to light through a fixed reflection mirror group 18. The body is layered around the outer periphery and an image is formed on a photoreceptor 6 that rotates in synchronization with the scanning optical system 3a.

In the vicinity of the photoreceptor 6, there is a registration roller 19,
A transfer device 20 is disposed, and furthermore, a conveyor belt 21 and a fixing section 22 are disposed, and a first flapper 23 is disposed downstream of the fixing section 22, and the flapper 23 is located on the discharge conveyance path Pa side. Alternatively, the refeed path pb side is switched in two directions, and a pair of conveyance rollers 25 is provided downstream of the discharge conveyance path Pa, and furthermore, a paper discharge tray is provided outside the machine downstream of the pair of conveyance rollers 25. 26 are arranged. Also,
A second flapper 29 is arranged downstream of the discharge conveyance path Pa.

Next, the copy mode will be explained.

If only one side of the sheet is to be copied, the sheet is moved to the first flapper 2, which is in the switched state shown by the broken line in FIG.
3, the sheets pass through the conveyance rollers 25 (pass through the discharge conveyance path Pa) and are sequentially accumulated on a tray 26 provided outside the copying apparatus. When double-sided copying or multiple copying is required, the sheet is moved by the guiding action of the first flapper 23, which is in the switching state shown by the solid line in the figure.
It is conveyed toward the second flapper 29 via the conveyance roller pair 27 (passing the refeed conveyance path pb). Here, when double-sided copying is performed, the second flapper 29, which is switched to the state shown by the solid line in the figure, moves the sheet along the conveyance path Pc.
The conveyance path Pe
If it is a large sheet, it will be collected on the intermediate tray device 36 via a pair of transport rollers 32, and if it is a small sheet, it will pass through a pair of transport rollers 32 and be collected on the second tray shown by the broken line in the figure. The sheets are guided onto the flapper 33 and then passed through a pair of conveying rollers 35 to be sequentially accumulated on an intermediate tray device 36. When multiple copies are to be made, the guide action of the second flapper 29, which has been switched to the broken line state in the figure, causes the paper to be transferred directly to the intermediate tray via the pair of conveying rollers 32, etc. in the same manner as in the case of double-sided copying described above. They are sequentially accumulated on the device 36. In this way, after a predetermined number of single-sided copied sheets are accumulated on the intermediate tray device 36, the second side of the previous original is placed on the original platen 2, or the original to be subjected to multiple copying is placed on the original platen 2, and both sides are copied. When the copy start button is operated, the paper refeed roller 45 and separation roller 46 in the intermediate tray device 36 are driven, and the sheets stacked on the intermediate tray device 36 are sequentially transported from the bottom to the conveyance roller pair 37 and the roller pair 38. The sheets are again conveyed to the copying section 5 through the above-described steps, and the sheets on which copying has been completed as described above are then conveyed to be stacked on the tray 26.

Figures 3 (a) to (C) and Figure 4 (a) to (e) are CC
The filter switching means for D52 is shown.

Inside the lens holder 56, the above-mentioned CCD lens 51 and a CC for detecting the light of the irradiated part of the document are installed.
D52 is provided on the same optical axis. A fixed shaft 57 is fixed to a part of this holder 56, and a rotatable filter holder 58 is attached to this holder 57. This filter holder 58 is provided with a red filter 55 and a blue filter 59. A spring 60 is hung between the filter holder 58 Q58a and the -0456a of the lens holder 56, and a stopper pin 100 provided on a part of the lens holder 56 stops the force of counterclockwise rotation. The blue filter 59, the CCD lens 51, and the CCD 52 are always located on the same optical axis.

Further, a lever 62 rotatable around a shaft 61 fixed on the lens holder 56 is hung on one end 58b of the filter holder 58, and the other end of the lever 62 is attached to a solenoid SL.

In Fig. 3 (a) to (C), the above solenoid SL is OFF.
4(a) to (c) show the state in which the solenoid SL is ON, that is, the state in which the blue filter 59 is applied.
In other words, it shows a state in which a red filter 55 is applied.

Next, the principle of document color recognition will be explained based on FIG.

Red (R), black (B), and white (W) are placed on the document glass 2.
An original O having color information is placed thereon, and the original 0 is illuminated by the light source 16.

The light information passing through the blue filter 59 is absorbed without being reflected in the B part, partially reflected in the R part, and reflected in the W part.
The signal is transmitted to the CCD 52. The analog signal of CCD2 is
As shown in the figure, since there is a difference between the normal light amount and that of W, a larger output signal can be obtained with W. The obtained analog signal is gain corrected, that is, corrected at a predetermined threshold level, and dark areas (Low output) are set to 0 and bright areas (High output).
The digital signal rooIJ is converted into digital information via the A/D converter 63 which sets h output to 1, and the digital signal rooIJ obtained by the conversion is recorded in the RAM 65 by the CPU 64.

On the other hand, the light information passing through the red filter 55 is not reflected in the B part as in the second section, and only the R and W parts are reflected by the CCD 5.
2. As shown in the figure, the analog signal of the CCD 52 has the same level of output only in the R and W portions due to the influence of the red filter 55. Similarly, the analog signal is
After the gain is corrected and converted into a digital signal by the A/D converter 63, the CPU 64 outputs the digital signal rl.
-01'' is recorded in the RAM 65.

In either case, the configuration is such that information for one page of the document is recorded in the RAM 65 by scanning by the scanning optical system 3a.

Then, by taking the logical sum of the above two pieces of information roo1j and “101”, we can obtain the information “100”.
With this, it is possible to recognize which part of the document is red (R).

By using such a method, it is possible to recognize the color and area of the document, and based on this information, the LED 50
By selectively lighting up via the driver 67,
Multiple copies are possible by specifying areas and erasing frames.

Next, the operation when detecting a red portion will be explained based on the flowchart shown in FIG.

At the initial stage, the blue filter 59 is applied. In this state,
The motor 73 is started to slow up (S-t, Fig. 7 (
When the scanning optical system 3a moves forward, the home position sensor S0 first detects the home position (S-2, see FIG. 7(b)), and then the image tip sensor S detects the image tip. detected (S-3, see FIG. 7(c)). When the tip of the image is detected, use this as a trigger to
Reading is started at regular intervals by the CD 52 (S
-4) The read data is sequentially stored in the RAM 65.
(S-5), where one raster data is a byte, and the first address of the RAM 65 where the read data is stored is m. Then, at the edge of the paper, the color changes from white, which is the paper background color, to yellow, which is the color of the pressure plate, and the read data is level 0 (all black) for all 1 raster.
When the paper edge is detected by the CCD 65 (S
-6, see FIG. 7(e)), the reading operation is aborted. At the same time, motor 73 is slowed down and then stopped. After stopping, the solenoid SL is turned on (see FIG. 7(d)), and the filter is switched from the blue filter 59 to the red filter 55 (S-7).

Next, the motor 73 is started up in the backward direction at the same speed as when forward, and the scanning optical system 3a is started backward (see S-8, FIG. 7(a)), so that the rotation angle is set to the slowdown angle ω when forward. . When it becomes the same as (S-9), the reading operation is started at the same cycle as when moving forward (S-10). Then, when moving forward, each raster data is stored in FILO (first in 1st out) from the last address where the tester data is stored.
) and compare it with each raster data at the time of 11th guard,
Color detection is performed (S-10) and the results are stored in RAM 6.
5 at address (n x a + m).

Then, during verification with n=0, the solenoid SL is set to 0FFL/(S-12, the seventh (see figure (d)), the filter is switched from the red filter 55 to the blue filter 59. And home position sensor S. When the home position is detected by (
S-13, see Figure 7(b)), slow down the motor 73, and then stop it (S-14, see Figure 7(a)
)reference).

The red color detection sequence for the original is now complete, and the RAM 65
The red part information remains inside.

Since the position of the red area can be easily calculated from the address stored in the RAM 65, based on this information, only the latent image of the red area or the latent image of the black area on the photoreceptor 6 is erased, and the image of the red area or the black area is erased. image of the area can be formed.

〔Effect of the invention〕

As described above, according to the present invention, the number of storage means for storing color image information can be reduced to one, and the cost can be reduced.

[Brief explanation of the drawing]

1 and 2 are main part configuration diagrams of the present invention, FIG. 3 is a diagram showing the filter switching means with a blue filter applied, FIG. 3(a) is a plan view, and FIG. ) is a sectional view taken along line 11, and FIG. 3(c) is a sectional view taken along line II-II. FIG. 4 is a diagram showing the filter switching means with a red filter applied. FIG. 4(a) is a plan view, FIG. 4(b) is a sectional view taken along the line III-III, and FIG. 4(c) is a plan view. It is a sectional view taken along the IV-TV line. Figure 5 is an explanatory diagram of the principle of manuscript recognition, Figure 6
The figure is an operation flowchart, and FIG. 7 is a timing chart. 3a...Scanning optical system 52...Charge coupled device 55-----Red filter 59--Blue filter 3...-A/D converter 64 ...-CPU 65...-RAM

Claims (1)

[Claims] a scanning means for optically scanning a document during forward movement and backward movement; and a color for extracting a first color from the original during forward movement and a second color during backward movement from the original. an image forming apparatus comprising: a storage means for storing information of the first color; and a first color information read from the storage means during scanning during backward motion and the color extraction means; An image forming apparatus comprising: color recognition means for performing color recognition based on extracted second color information.