JPH03122679A - Image forming device - Google Patents

Abstract

PURPOSE:To always reproduce a color as same as that of an original by automatically switching a color developing device in accordance with the color of image of the original. CONSTITUTION:The device is provided with a 1st image pickup means A converting the optical image of an original image into an electrical signal by photoelectric conversion and a 2nd image pickup means D converting the optical image of an original image transmitted through plural color filters C into an electrical signal by photoelectric conversion, and a specified chrominance signal and another chrominance signal different from the specified one are separated from output signals from the 1st and the 2nd image pickup means A and D. A filter exchange means B which selects one of the plural color filters and sets it in one of optical paths is provided, and the 2nd image pickup means D converts the optical image transmitted through the color filter set by the filter exchange means B into the electrical signal. In such a case, the color developing device is automatically exchanged corresponding to the color filter in accordance with the result of the color detection of the original obtained by exchanging the color filter. Thus, the image is automatically formed in the developing color as same as the chrominance signal separated by a color separation means E and an operation if simplified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image forming apparatus such as a copying machine or a facsimile machine, and particularly relates to an image forming apparatus that forms images in two colors in one image forming process. .

[Prior Art] Conventionally, a reading unit converts a document into an electrical signal and reads it, an image processing unit converts the electrical signal into a digital image signal, and a dot-type recording unit such as a laser beam printer forms a digital image. Digital copying machines have been provided, and among such copying machines, a two-color copying machine is known that automatically identifies and records black and red parts of a document. Copying machines are also known that write images (latent image formation) for each color in a single copying process and develop the images. Furthermore, a so-called one-shot two-color digital copying machine as described above which combines both of these functions has been proposed.

[Problems to be Solved by the Invention] However, when performing two-color recording in one shot in the conventional apparatus as described above, recording can only be performed in two predetermined colors. Therefore, for example, if there is red in the original after color separation, and there are black and blue developing devices in the main body of the apparatus, red cannot be reproduced. In this case, the user (operator) has to issue an instruction to replace the developing device through the operation unit, which is a cumbersome operation.

An object of the present invention is to eliminate the above-mentioned drawbacks and to create an image that can always reproduce the same color as the original by automatically and appropriately switching the color developing device according to the color of the original image. An object of the present invention is to provide a forming device.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a first imaging means that converts an optical image of an original image into an electrical signal by photoelectric conversion, and a first imaging means that converts an optical image of an original image into an electrical signal, and a first imaging means that converts an optical image of an original image into an electrical signal, and a second imaging means that converts an optical image of an image into an electrical signal by photoelectric conversion; and a specific color signal and another color signal different from the specific color from the output signals of the first and second imaging means. A color separation means for separating, and a color separation means for separating a first color on a photoreceptor based on the specific signal separated by the color separation means. a first latent image forming means for forming a latent image; and a second latent image forming means for forming a second latent image on the photoreceptor based on the another color signal separated by the color separating means. means, a first developing means for developing the first latent image with a specific color developing material, and a first developing means for developing the second latent image with a color developing material of another color different from the specific color. and an automatic developing device changing means that has a plurality of developing devices of the second developing device for each color, and exchanges and sets a developing device of a color developing material corresponding to the different color signal to a predetermined developing position. and forming the first latent image and forming the second latent image during one image forming process.

Further, the first aspect of the present invention further includes filter exchanging means for selecting one of a plurality of color filters and setting it in one of the optical paths, and the second imaging means is set by the filter exchanging means. It is characterized by converting the optical image transmitted through the color filter into an electrical signal.

Further, the second aspect of the present invention further includes determining means for determining whether or not a predetermined color signal is output from the color separation means during pre-scanning, and the filter replacing means in response to a negative determination by the determining means. The present invention is characterized by comprising a control means for driving and controlling the color filter to cause the color filter to be replaced with another color filter, and to cause the prescan to be performed again.

Further, a third aspect of the present invention has a color specifying means for specifying a color to be developed by the second developing means, and the control means selects the specified color according to the color specification of the color specifying means. The present invention is characterized in that the filter exchange means and the automatic developer exchange means are drive-controlled in order to set the color filters and the developer.

Further, a fourth aspect of the present invention includes a color specifying means for specifying a color to be developed by the second developing means, and the control means includes:
When the determining means determines that one of the specific colors could not be separated by the color separating means even if the color filters are replaced with other color filters among the plurality of color filters, the color specified by the color specifying means is The present invention is characterized in that the developing device is replaced via the automatic developing device changing means, and development is performed in the designated color.

Further, in a fifth aspect of the present invention, when detecting the color of the original by pre-scanning an optical system that forms an optical image of the original image on the first imaging means and the second imaging means, The control means is characterized in that when the optical system moves forward, color detection is performed using one color filter, and when the optical system moves backward, color detection is performed using another color filter.

[Function] In the present invention, the color developing device is automatically replaced in accordance with the color filter in accordance with the color detection result of the document obtained by replacing the color filter. Image formation can be automatically performed using the same development color as the color signal, and the operation is also simplified.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

A. Basic configuration FIG. 1 shows the basic configuration of an embodiment of the present invention. In this figure, A is a first imaging means that converts an optical image of a document image into an electrical signal by photoelectric conversion. Reference numeral B denotes a filter conversion means for selectively exchanging one of the plurality of color filters C and setting it in one of the optical paths. Reference numeral D denotes a second image pickup means that converts the optical image of the original image transmitted through the plurality of color filters C set by the filter exchange means B into an electric signal by photoelectric conversion. Reference numeral E denotes a color separation means that separates a specific color signal from the output signals of the first and second imaging means A and D into another color signal different from this specific color.

Reference numeral F denotes a first latent image forming means for forming a first latent image on the photoreceptor G based on the above-mentioned specific signals separated by the color separating means E. Reference numeral H designates a second latent image forming means for forming a second latent image on the photoreceptor G based on the separate color signals separated by the color separating means E. (2) is a first developing means for developing the first latent image with a color developing material of a specific color. J is a second developing means that develops the second latent image with a different color developing material from the above-mentioned specific color. Reference numeral K denotes an automatic developer changing means which has a plurality of developing devices of the second developing means J for each color and sets the developing device of the color toner corresponding to the above-mentioned different color signal to a predetermined developing position.

Denoted at L is a determination means for determining whether a predetermined color signal is output from the color separation means E during pre-scanning. M
is a control means that drives and controls the filter replacement means B in response to a negative determination by the determination means to cause the filter to be replaced with a color filter of a different color and to perform a prescan again. Further, the present apparatus forms the first latent image and the second latent image during one image forming process.

Fig. 2 shows an embodiment of the present invention (hereinafter referred to as Embodiment 1).
In this figure, which schematically shows the cross-sectional structure of a one-shot two-color digital image forming apparatus, IOQ is an image reading device (hereinafter referred to as a reader), and 200 is an image writing device using a laser (hereinafter referred to as a printer). ). Also,
300 is red and blue.

This is an automatic color changer (ACC) that stores developing units for green and magenta colors.

First, the reader portion 100 will be explained.

101 is a CCD (charge coupled device) for image reading;
Approximately 50 pixels so that 400 pixels per inch can be read
A CCD with 00 pixels is used. 102 is CC for color identification
D, image reading C (: 5000 equivalent to D201)
It uses a pixel CCD. 103 is CGD1 for color identification
02 CCD filter, red (R), green (G),
It is equipped with three types of blue (B) color filters, and each filter can be switched and used using a solenoid (not shown). 104 is a reflection mirror that changes the optical path of the reflected light from the original at a right angle; 105 is a CGDIO+; a condensing lens (imaging lens) that focuses the original image on 102; and 106 is an original glass on which the original is placed. .

Next, the printer section 200 will be explained.

A photosensitive drum 201 is exposed to laser light to form a latent image. A primary charger 202 charges the drum 201 with a negative charge. A recharging device 203 applies a negative charge for a color image to the area on the drum 201 where a black image is formed.

204 is a pre-transfer charger that charges the drum 201 immediately before transferring the toner image on the drum 201 to the transfer paper; 205 is a transfer charger that transfers the toner image on the drum 201 to the transfer paper; 206 is a transfer completed device; This is a separation charger for separating the transfer paper from the drum 201. 207 is drum 2
208 is a pre-exposure lamp that neutralizes the charge on the drum 201.

209 is a black image laser beam generated in response to a black image signal, and 21G is a color image laser beam generated in response to a color image signal. A black toner developing device 211 develops a latent black image on the photosensitive drum 201 with black toner. 212
is a color toner developer that develops a latent color image on the photosensitive drum 201 with color toner, and this color toner developer 21
2 can be replaced with a specified (desired) color.

213 is an octahedral polygon scanner that scans the rotating photosensitive drum 201 with laser light emitted from lasers 209 and 210. 214 is a fixing device for fixing the toner image on the transfer paper; 215 is a flapper for switching the transport path of the transfer paper to an intermediate tray for double-sided/multiplexing to be described later;
Reference numeral 216 is a flapper for switching the conveyance path to switch back when duplexing or to proceed as is when duplexing is in duplex or multiplex mode. Reference numeral 217 denotes a switchback stepping motor, which rotates a rotor in response to a detection signal from a sensor (not shown) to switchback the transfer paper and turn it over.

Reference numeral 218 denotes an intermediate tray that temporarily stores transfer paper during duplex/multiple printing. However, even in duplex/multiple copying, when the number of copies is small, the transfer paper is not stored in the intermediate tray 218 and is re-fed straight.

219 and 220 are cassettes that hold transfer paper.

221 is a paper deck that can store 2000 sheets of ^4 size transfer paper.

Next, the automatic color changer (ACC) 300 will be explained.

300 is a multicolor unit (MCtl) automatic color changer. 301 is a blue (B) developer,
302 is a place where a green (G) developer is stored, 303 is a place where a red (R) developer is stored, and 304 is a place where a magenta (M) developer is stored.

By docking (connecting) the MC030'0 with the printer section 200 of the main body, it is possible to automatically replace the color developing device on the main body 200 side. This exchange operation is controlled by a control section on the main body 200 side. In addition, the main body 200
To change the color developer on the side to a color developer of any specified color, press M.
The CU unit itself 300 is vertically moved up and down for positioning.

Next, an image forming process according to an embodiment of the present invention will be explained with reference to FIG.

The copying process of this embodiment is a known two-color development process.

FIG. 3(A) shows the state when a black image is formed, and FIG. 3(B) shows the state when a color image (for example, red) is formed. Third
As shown in (^) in the figure, first, in forming a black image, the surface of the photosensitive drum is charged by the -forming charger 202 at a
V can be charged uniformly. Black image laser light 209 is irradiated onto the uniformly charged surface where black toner is to be placed.

Only where the laser beam hits, the potential drops to about -100V. Negatively charged toner is ejected from the black developing device 211 toward the area irradiated with this laser light. That is, a developing bias is applied to the developing cylinder 222 in the black developing device 211 so that the area hit by the laser beam becomes black.

After that, as shown in FIG. 3(B), the recharger 203
After further negative charging, a color signal laser beam 210 is irradiated onto the area to be colored. This laser light 2
The voltage dropped to about 1,300V at the point where No. 10 was irradiated, and the color developer 2
12, the area hit by the laser light is developed in color.

Next, processing for a portion where black data and color data are adjacent will be explained with reference to FIG.

(C), (D), and (E) in FIG. 4 show the surface potential on the photosensitive drum 201. This figure is used as image data (
When a black image and a color image are adjacent to each other as shown in ^), several color pixels in the adjacent portion are deleted and supplied to the laser generator 230 as shown in (B) of the figure.

Based on the deleted image data, first the photosensitive drum 201 is
On the other hand, a black developing device is charged with an electric charge, and a portion corresponding to a black pixel is irradiated with a black laser beam 209 to attenuate the electric charge.
Place black toner on the low-charge area ((C) in this figure)
reference). Next, the photosensitive drum 201 is charged with electric charge for color development (see DJ in this figure), and the portions corresponding to color pixels are irradiated with color laser light 210 to attenuate the electric charge. (See (E) in this figure.) By doing this, in this embodiment, color mixing occurring in the adjacent portions of the black pixel and the color pixel is prevented.

FIG. 5 shows the circuit configuration of image data processing from image reading to output in this embodiment.

Two CCDs (charge coupled devices) that are image sensors
Image signals manually generated from the signals 101 and 102 by photoelectric conversion are separated into two signals, black and color (for example, red), by a color separation unit 501.

The color separation method in this color separation section 501 will be explained next.

For example, taking the color red as an example, first, a red filter is selected as the filter 103, an image not passed through the filter is input to the image reading CGDIOI, and the color detection Cfl:D10
2 contains an image that has been passed through a red filter.

FIG. 6 shows the color separation section 501 of FIG. 5 in more detail. As shown in FIG. 6, CCD10I.

The analog image signals from 102 are converted into 8-bit signals by A/D converters 601 and 602, respectively, at a level corresponding to the pixel density.
It is converted into a digital signal of t (bits). This digital signal is processed by the correction circuit units 603 and 604 (:CD10
Variations in black density of 1°102, variations in light amount distribution of the document illumination lamp, etc. are corrected. On the other hand, the correction circuit section 604 also simultaneously corrects the digital signal according to the change in white level and the density using a color filter.

Thereafter, the two image signals output from the correction circuit units 603 and 604 are manually input to the comparison circuit 605. Comparison circuit 605
Now, the image signal of the CGDIOI for reading is S, and the image signal of CGDIOI is for color detection.
Assuming that the image signal of the CD 102 is F, if 5-F=O, it is regarded as a black signal, and the image signal S is used as black signal data A.
If S-F≠0, it is regarded as a red signal and the image signal S is output as red signal data B.

The black signal data A and the red signal data B outputted from the color separation section 501 are input to the adjacent data deletion section 502 shown in FIG. Deletion processing is performed. The data signal for which this processing has been completed is then manually input to the density conversion unit 503 and subjected to a predetermined density conversion process.After that, the black signal data is input as is to the image processing filter 505, but the red signal data is input to the image processing filter 505. Buffer memory 5 that corrects recording timing discrepancies
04 and is delayed for a certain period of time before being input manually to the image processing filter 505. The black signal output from the image processing filter 505 is converted into black laser light by the laser generator 230 and emitted, and the red signal is simultaneously converted into color laser light and emitted.

Next, an example of operation during two-color copying using color separation detection according to the embodiment of the present invention will be described.

The flowchart in FIG. 7 shows the operating procedure. In addition,
F represents a step number. First, when the copy start key (copy key) on the operation unit (not shown) is pressed at F7-1,
Before starting the copying operation, perform prescanning to detect the density level and color of the original (F7-2)
. Initially, a red filter is set in the position of the filter 103 in FIG. and red (black/red) two-color copying processing is performed (F7-4). Details of the copying process of 20F7-4 are shown in the flowchart of FIG.

If red is not detected at F7-3,
After returning the optical system driven by prescan to its initial position (
F7-5), the blue filter is set at the position of the filter 103 (F7-6), and two-color copying processing of black and blue (black/blue) is performed (F7-7). Details of the copying process of F7-7 are shown in the flowchart of FIG.

FIG. 8 shows the operating procedure during the above-mentioned two-color black/red copying. F
If the red developer is set in IO-1, FIO-
Proceed to step 3, but if the red developer is not set, press M
Drive C1130G and replace the set color developer with a red developer (FIO-2). After replacing the developing device, the FIO-3 performs the above-mentioned one-shot two-color copying of black and red.

FIG. 9 shows the operating procedure for the above-mentioned black/blue two-color copying. F
When the blue developer is set in il-1,
Proceed to step 3, but if the blue developer is not set, use MC.
11300 to replace the set color developer with a blue developer (Fil-2). After replacing the developing device, one-shot two-color copying of black and blue is performed using Film-3.

In the first embodiment of the present invention described above, colors are separated by pre-scanning and a developer is selected based on the result of the color separation, but the operator may specify any color.

The operation procedure of the second embodiment of the present invention in this case will be explained with reference to the flowchart of FIG.

At F8-1, the operator can specify an arbitrary color using a color specification key on the operation section (not shown).

Thereafter, when the operator presses the copy start key at F8-2, a corresponding filter capable of separating the specified color is selected and set at the filter setting position 103 at F8-3 (F8-3). In addition, in the next step F8-4, it is determined whether the developer corresponding to the specified color is set at the developer set position of the second latent image, and if the developer is not set, the next Drive the MC1300 with F8-5 to replace the developer with the specified color. Thereafter, at F8-6, one-shot two-color copying of black and designated color is performed while separating the colors in real time.

9-1 The flowchart of FIG. 11 shows the operating procedure of the third embodiment of the present invention when a specific color is found and copied while switching filters for a plurality of colors. First, in automatic color detection mode, when the copy start key is pressed by the operator (
F9-1), and the red filter is set at the filter set position 103 (F9-2).

This is because red is the priority color and blue is the second priority color, and the priority color can be changed by the operator manually using keys on the operation unit (not shown).

Prescanning is performed for color detection using the red filter (F9-3). Color separation circuit 50 during advancement of the optical system
The color signals separated in step 1 are stored in the color storage section 506 in FIG. Here, the only thing to be stored is whether or not there was a red light.

After that, when the optical system reaches the inversion position (F9-
4) Read the contents of the color storage unit 506 to determine whether there is a red light (F9-5). If there is a red light, return the optical system to the home position (F9-6.
F9-7). Thereafter, two-color copying of black and red is performed in the aforementioned process shown in FIG. 8 (F9-8).

On the other hand, if there is no red signal at F9-5, the filter 103 is switched from the red filter to the blue filter (F9-5).
10) Move the optical system backwards (F9-11).

While the optical system is moving backward, color signals are stored in the color storage section 506 using the color separation circuit 501. When the optical system returns to the home position (F9-12), read out the contents of the color storage section 506 to determine whether or not there is a blue signal (F9-13).
Copying in two colors, black and blue, as shown in the figure is performed (F9-14). However, when there is no blue signal, the blue filter is released from the filter set position (F9-15) and copies are made with only black (
F9-16).

[Effects of the Invention] As explained above, according to the present invention, the color developing device is automatically replaced according to the result of color detection of the document obtained by replacing the color filter, so that the color separating means Image formation can be automatically performed using the same developed color as the separated color signal, and as a result, operations can be simplified.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of an embodiment of the present invention, FIG. 2 is a sectional view showing a schematic internal structure of a digital image forming apparatus according to an embodiment of the present invention, and FIG. 3 is a block diagram showing the basic configuration of an embodiment of the present invention. FIG. 4 is an explanatory diagram showing the process steps of color development. FIG. 4 is an explanatory diagram showing the process steps of two-color development to prevent color mixture in the embodiment of the present invention. FIG. 6 is a block diagram showing the circuit configuration of the color separation unit in FIG. 5, FIG. 7 is a flowchart showing the operation procedure of the first embodiment of the present invention, and FIG. Black/Red 2 executed in
A detailed flowchart showing the operation of color copying, FIG.
10 is a detailed flowchart showing the operation of color copying. FIG. 10 is a flowchart showing the operating procedure of the second embodiment of the present invention. FIG. 11 is a flowchart showing the operating procedure of the third embodiment of the present invention. ...Image reading device (reader), ...CCD for image reading, ...CC01 for color identification ...filter, ...image writing device (printer), ...photosensitive drum, ...return Charger, ...Laser light for black image, ...Laser light for color image, ...Developer for black toner, ...Developer for color toner, ...Laser generator, ...Auto Color changer (^CC), ~304
...Developer, ...Color separation section, ...Adjacent data deletion section, ...Density conversion section, ...Buffer memory, ...Image processing filter, ...Color storage section. (A) Figure 3 (B) Riyuji side dishes, -1 Figure 8 Figure 10

Claims (1)

[Scope of Claims] 1) A first imaging device that converts an optical image of a document image into an electrical signal by photoelectric conversion; and a first imaging device that converts the optical image of the document image that has passed through a plurality of color filters into an electrical signal by photoelectric conversion. a second imaging means for separating a specific color signal and another color signal different from the specific color from the output signals of the first and second imaging means; a first latent image forming means for forming a first latent image on the photoreceptor based on the separated specific signal; and a first latent image forming means for forming a first latent image on the photoreceptor based on the different color signal separated by the color separation means. a second latent image forming means for forming a second latent image thereon; a first developing means for developing the first latent image with a specific color developing material; and a first developing means for developing the first latent image with a specific color developing material; A second developing means for developing with a color developing material of a different color from the color of the second developing means, and a plurality of developing devices of the second developing means for each color, and a color developing material corresponding to the different color signal is provided. an automatic developing device exchange means for exchanging and setting the developing device to a predetermined developing position, and forming the first latent image and forming the second latent image during one image forming process. An image forming apparatus characterized by: 2) The second imaging means further includes a filter exchanging means for selecting one of the plurality of color filters and setting it in one of the optical paths, and the second imaging means captures a light image transmitted through the color filter set by the filter exchanging means. The image forming apparatus according to claim 1, wherein the image forming apparatus converts the image into an electrical signal. 3) Further, determining means for determining whether or not a predetermined color signal is output from the color separation means during pre-scanning, and a determining means for determining whether or not a predetermined color signal is output from the color separation means, and driving and controlling the filter replacement means in response to a negative determination by the determining means to output a different color. 3. The image forming apparatus according to claim 2, further comprising a control means for causing the filter to be replaced and for pre-scanning to be performed again. 4) It has a color specifying means for specifying a color to be developed by the second developing means, and the control means sets a color filter of the specified color and a developing device in accordance with the color specification of the color specifying means. 4. The image forming apparatus according to claim 3, wherein said filter changing means and said developing device automatic changing means are drive-controlled to achieve this. 5) A color specifying means for specifying a color to be developed by the second developing means, and the control means is configured to control one of the specific colors even if the color filter is replaced with another color filter among the plurality of color filters. When the determining means determines that the color separation could not be performed, the developing device is replaced with a developing device of the color designated by the color specifying means via the developing device automatic exchange means, and development is performed with the designated color. The image forming apparatus according to claim 3, wherein the image forming apparatus performs the image forming apparatus. 6) When detecting the color of a document by pre-scanning an optical system that forms an optical image of the document image on the first imaging device and the second imaging device, the control device controls the optical system. Image formation according to any one of claims 3 to 5, characterized in that color detection is performed using one color filter when the optical system moves forward, and color detection is performed using another color filter when the optical system moves backward. Device