JP2646583B2 - Two-color copying machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-color color copying apparatus that performs copying in two colors of a specific color and another color other than the specific color, and more particularly, to a so-called one-pass type. The present invention relates to an improvement of a two-color copying apparatus of a type capable of editing a two-color image based on various editing modes.

2. Description of the Related Art Various apparatuses for obtaining a multicolor copy image of two or more colors from a multicolor original have been conventionally provided.

The most common device is to separate the image on the original with three kinds of color separation filters of red, blue and green, and to execute each copying process on the light image of each separated color, and to make one copy A so-called full-color image is obtained by superimposing images of each color on a sheet.

However, in such a color copying apparatus, it is necessary to take synchronization (registration) for superimposing images of each color on one copy sheet, and the configuration and control of the apparatus become extremely complicated. A situation arises in which the size of the apparatus increases and the cost increases. In addition, in general, a multicolor image to be copied is mostly black characters and figures except for very special cases, and underlines or marks such as red are mostly provided as other colors. In some cases, it is uneconomical to use a full-color copying apparatus for this type of document. Further, in this type of full-color copying apparatus, a black visible image is formed by mixing three colors.
Not only is it not pure black, it is not only less reproducible than the image obtained using pure black toner alone, but the characters and the like that make up the black image portion are often thin line images. In some cases, interpretation becomes difficult.

Therefore, for an original document that is mostly occupied by a black image, a black-plus-one-color (red, blue, green, etc.) two-color color copying apparatus is sufficient. It is desired to maintain image quality equivalent to that of a (monochromatic) copying apparatus.

2. Description of the Related Art Conventionally, as a two-color copying machine of this type, for example, one disclosed in Japanese Patent Application Laid-Open No. 55-73063 is known. This is to form an electrostatic latent image for black and other specific colors using an optical imaging system including a light source, a mirror, and an imaging lens on one photoconductor, and a corresponding color toner is used. Each electrostatic latent image is developed with toner by a developing means, and each toner image is transferred to a copy sheet after both developing steps are completed.

[Problems to be Solved by the Invention] However, in this type of two-color copying machine,
Since it is necessary to distinguish the electrostatic latent image for black from the electrostatic latent image for other colors, to form a ternary latent image in which the latent image potential has three levels,
In addition to the problem that color mixing occurs at the boundary of the latent image due to the fringe electric field, the quality of the black image deteriorates compared to the conventional monochrome copying machine, and a special laminated photoconductor that can form a ternary latent image However, there is a problem that the process of forming the electrostatic latent image is complicated and the cost is increased. Also, since the latent image of the original image is formed using the optical imaging system, it is possible to copy a two-color original in two colors. It is not possible to edit the original image in various modes, such as copying both color portions with the same color, erasing one color of a two-color original, copying, or copying the original while transferring it. Problems arise.

As means for solving this kind of problem, Japanese Patent Application Laid-Open No. 56-162755
No. published in the official gazette has already been provided. This involves forming an electrostatic latent image for black on a single photoreceptor using an optical imaging system, transferring a black image developed with black toner to a copy sheet, and transferring an image of a specific color on the original document. Extracted by an image sensor and forms an electrostatic latent image for a specific color on a photoconductor based on an image signal from the image sensor,
A specific color image developed with a specific color toner is additionally copied on a copy sheet.

According to this type, the black image is formed based on the latent image formed by the optical imaging system, so that the black image quality can be kept good, and the image signal from the image sensor is transmitted. If you edit it appropriately,
It is possible not only to copy a two-color document in two colors, but also to realize various editing of a document image such as copying both a black portion and another specific color portion of the document in the same color. .

However, in this type, since a specific color image is superimposed on a black image already formed on a copy sheet and synthesized, it is necessary to precisely position each color image on the copy sheet. In addition to this, there is a problem that the cost of the apparatus increases, and in addition, since the photosensitive member needs to be rotated twice in performing the two-color copying process, the cycle operation time of the two-color copying process increases. Occurs.

In order to solve such a problem, it is assumed that the technology described in Japanese Patent Application Laid-Open No. 56-162755 is applied to a one-pass type in which one cycle operation of a two-color color copying process is completed while rotating the photoconductor one revolution. However, in the case of the one-pass type, since the development is performed on the photoconductor repeatedly, the first color toner image is scraped off during the second color development, or the second toner is added to the first toner image. There is a serious defect that they are mixed, and there is a problem that it becomes a big obstacle in practical use. Also, when performing image editing, the image information is limited to the range of the image information in the document, so that image editing using image information other than the image information in the document cannot be performed. There is also a problem that cannot be satisfied.

[Means for Solving the Problems] The present invention has been made in view of the above problems, and has improved the quality of a black image and a two-color image while reducing the apparatus cost. It is an object of the present invention to provide a two-color copying machine capable of diversifying image editing without being limited to an image information range in a document while maintaining the same.

That is, as shown in FIG. 1, a two-color color copying apparatus according to the present invention comprises a photoreceptor 1 for forming a latent image and An optical imaging system 3 for forming a latent image, a color separation means 4 selectively disposed in an optical path of the optical imaging system 3, and an image for reading an original 2 image and converting it into an electric image signal Reading means 5,
An image signal generating means 6 for outputting a predetermined pattern image as an electric image signal, and a first image signal on the photosensitive member 1 based on an image signal from one of the image reading means 5 and the image signal generating means 6. A light output unit 7 for forming a second latent image in a state in which the latent image is inverted, an image area designating unit 8 for designating a specific image area on the document 2, and the first or second latent image A charge removing unit 9 for removing charges in an area designated by the image area designating unit 8 when forming, an edit mode selecting unit 10 for selecting an image editing mode of the original 2, and a mode selected by the editing mode selecting unit 10. Edit mode control means 11 for controlling each of the latent image forming means 4, 7, 9 and the like to form the first and second latent images according to the first latent image and the second latent image with the first color toner Positive or negative development of latent image formed earlier among latent images That the first developing means 12, the first two-component developer in which the second color toner and densities of different color toners and the charging characteristics consisting of 4g / cm ³ or less of the magnetic carrier is accommodated, the second A second developing unit 13 for developing a latent image formed later of the first and second latent images with a different color toner by a method different from that of the first developing unit 12; Transfer means 15 for transferring each color toner image on the photoreceptor 1 to the copy sheet 14 after the development process by means 12 and 13 is completed.
It is provided with.

In such technical means, the photoreceptor 1 may be in a drum shape or a belt shape.

Further, the optical imaging system 3 may be a slit exposure type (platen moving type, platen fixed type) or a full exposure type using a flash light source.
Further, the present invention can be applied to either a fixed magnification type or a variable magnification type. Further, the color separation means 4 can be appropriately selected, including a filter, as long as it can optically extract an appropriate color component on the document 2, and separates only one color. Alternatively, a plurality of colors may be arbitrarily separated by switching and selecting as appropriate.

Further, as the image reading means 5, if it can read two images of the original and extract it as an electric image signal,
A color image sensor using a CCD (charge coupled device) or a combination of a black-and-white image sensor and a color separation means such as a filter may be appropriately selected, but in consideration of the reading sensitivity, a black-and-white imager sensor is used. It is preferable to use a combination with a color separation means. The image signal generating means 6 may be appropriately selected as long as it can generate an image signal of an arbitrary electric pattern such as a computer graphics device. As the light output means 7, various known devices such as an LED array, a liquid crystal micro shutter array, a fluorescent display tube array, a magneto-optical shutter array, and a semiconductor laser scanner can be used.

Further, as the image area designating means 8, if it is possible to designate an arbitrary area of the document 2, the design may be changed as appropriate, such as an application of an electromagnetic induction type digitizer. In consideration of manuscript designability, it is preferable that the document 2 is incorporated in a manuscript cover usually provided to suppress the manuscript 2. The charge removing means 9 can be appropriately selected as long as it can remove the electric charge at a corresponding portion on the photoconductor, such as one using an exposure process using a light source.

The editing mode selection means 10 is set to a mode in which editing processing can be performed in the image information range in the original 2, such as a mode in which a part of the original 2 is color-converted or a part of the original 2 is partially erased. In addition, it is possible to select a mode to which image information other than the document 2 is added. In this case, if the selection mode can be directly displayed on the console panel, the operability of the operator can be improved. The editing mode control means 11 may be appropriately designed and modified as long as it can execute the selected editing mode. However, from the viewpoint of cost, a basic control function using a microprocessor or the like can be used. Is preferably designed to be added to

Further, the first and second developing means 12 and 13 are first and second positive, positive development corresponding to the negative electrostatic latent image,
As long as the negative development is performed, the developer to be used, the development method and the like may be appropriately selected, but in order to surely avoid the situation of scraping the first color toner image and mixing of the second color toner. Preferably, in the second developing means 13, a two-component developer composed of a color toner and a magnetic carrier having a density of 4 g / cm ³ or less is used. In this case, as the magnetic carrier, a porous carrier, a ferrite carrier, a carrier in which a magnetic powder is dispersed in a resin binder, and the like can be appropriately selected, but a carrier in which the magnetic powder is dispersed in a resin binder is It is preferable because the density can be easily adjusted by the content of the magnetic powder.

The transfer means 15 may be appropriately selected from those using an electrostatic transfer method or a heat transfer method.

[Operation] According to the above-described technical means, a two-color image (including a single-color image) on the document 2 is independently formed on one photoconductor 1 by the two systems of latent image forming means 3 to 9. Alternatively, the latent image is basically formed as a two-system positive latent image or a negative latent image with another image added thereto, and each latent image is formed by a corresponding one of a first developing unit 12 and a second developing unit 13, respectively. After the development, each toner image is transferred to one copy sheet 14 by the transfer means 15.

In such a copying process, in forming each latent image on the photoreceptor 1, the edit mode control means 11 takes into account image information other than the document 2 according to the mode selected by the edit mode selection means 10. Since the two systems of latent image forming means 3 to 9 can be controlled, it is possible to obtain an edited image as a latent image on the photoreceptor 1 in a range exceeding the image information in the document 2. Further, since the two types of latent images are formed in a state where they are inverted with respect to each other, and are developed with each other by the respective developing means 12 and 13, the first image which has already been formed during the developing process of the second developing means 13 is formed. Is hardly affected.

Hereinafter, the present invention will be described in detail based on an embodiment shown in the accompanying drawings.

FIG. 2 shows an example in which the present invention is applied to a two-color copying machine for copying a color original, which is mostly composed of black images, as a two-color image of black and red.

In FIG. 1, reference numeral 1 denotes a photosensitive drum having a photosensitive layer provided on an outer peripheral portion, 2 denotes a color original (including a monochromatic original) including a black image and a red image, and 3 denotes an optically scanned original 2. An optical image forming system for forming a latent image on the photosensitive drum 1, an optical filter 4 as a color separating means selectively interposed in an optical path of the optical image forming system 3, and 5 for reading an image of the original 2 An image reading device for outputting as an electric image signal; 6, an image signal generating device for generating an image other than the image of the original 2 as an electric image signal; 7, an LED array as light output means; A coordinate reading device as image area designating means incorporated in 21; 9 an eraser for removing the charged charges on the photosensitive drum 1 based on the coordinate information read by the coordinate reading device 8; 10 an editing for selecting various editing modes. Mode selection switch, 11 An edit mode control device 12 for controlling each latent image forming device such as the optical filter 4, the LED array 7, and the eraser 9 according to the edit mode selected by the mode selection switch 7, and 12 is a black toner disposed around the photosensitive drum 1. , A second developing device using red toner, 14 is a copy sheet, and 15 is provided after each of the developing devices 12 and 13. A transfer corotron is provided as a transfer unit.

Reference numeral 20 denotes the original 2 when the original 2 is stacked and scanned.
, A document cover 21 for holding down the document 2 placed on the platen 20 from above, and a platen 22 disposed before the first developing device 9 to charge the surface of the photosensitive drum 1. A single charging corotron 23 is disposed in front of the second developing device 10 to charge the surface of the photosensitive drum 1, and a second charging scorotron 24 uniformizes the charge of the toner image on the photosensitive drum 1 during the transfer process. A pre-transfer corotron 25 is provided at the subsequent stage of the transfer corotron 12 and is a peeling corotron for peeling the copy sheet 11 having undergone the transfer process from the photosensitive drum 1. A cleaner 26 is provided for removing residual toner on the photosensitive drum 1. And 27, a pre-clean corotron disposed before the cleaner 26 to remove residual charges on the photosensitive drum 1, and 28 disposed behind the cleaner 26 to reliably remove residual charges on the photosensitive drum 1. Remove 29, a sheet feed tray for storing the copy sheet 11, 30 a sheet feed roll for feeding the copy sheets 11 in the sheet feed tray 29 one by one, and 31 for transferring the copy sheet 11 at a predetermined timing. Resist transport rolls to be delivered to the site, 32 is a transport belt that transports the copy sheet 11 after the transfer process is completed, 33 is a fixing device that fixes a transfer image on the copy sheet 11 transported by the transport belt 32, and 34 is a fixer This is a discharge tray for discharging and storing the copied copy sheet 11 after the process.

In this embodiment, the optical imaging system 3 includes a platen
A fixed exposure lamp 35 for continuously irradiating the document 2 on the slit by moving the document 20 in the direction a, and a light image from the document 2 irradiated by the exposure lamp 35 is guided to the photosensitive drum 1 through a predetermined optical path. Multiple mirrors 36 (specifically 36
a, 36b) and an imaging lens 37 interposed in the optical path to form an optical image of the document 2 on the photosensitive drum 1. As shown in FIG. 3, the optical filter 4 includes, for example, a red filter 41 that transmits only a red component, an ND filter 42 that transmits light from the optical imaging system 3 as it is, and a light blocking filter that does not transmit light. (Light shielding plate) 43 is appropriately rotated and driven by a drive motor 44, and any of the filters 41 to 43
Are selectively disposed in the optical path.

Further, as shown in FIGS. 2 and 4, the image reading device 5 is provided with an exposure lamp 51 provided separately from the exposure lamp 35 of the optical imaging system 3, and is irradiated with the exposure lamp 51. A light converging lens 52 for forming a light image from the surface of the document 2 on a predetermined portion, a half mirror 53 disposed in an optical path of light transmitted by the light converging lens 52, and a light transmitted by the half mirror 53 or Image sensor 54 for black and white receiving reflected light
(Specifically, 54a and 54b) and a red filter 55 interposed in the optical path between the half mirror 53 and the second image sensor 54b. The output of each image sensor 54 is a signal The data is input to the processing circuit 56.

In this embodiment, the signal processing circuit 56 operates to drive the LED array 6 based on the output from each image sensor 54 to form an electrostatic latent image corresponding to a red image on the photosensitive drum 1. And is controlled by a microprocessor described later. As the signal processing circuit 56, for example, a circuit as shown in FIG. 5 is used.

In the figure, the image signals photoelectrically converted by the respective image sensors 54a and 54b are amplified by an amplifier (amplifier) 61, respectively, and then converted to an A / D (analog / digital) converter 62.
Is converted into a digital signal, and the variation in output is corrected by a known shading correction circuit 63. Further, a multiplier 64 is provided with a correction coefficient supplied from a gain correction coefficient circuit 65, and the multiplier 64 adjusts a level difference of a signal resulting from a difference in sensitivity between the image sensors 54a and 54b with respect to a color. ing. The level of the black-and-white signal Sa and the red signal Sb whose level has been adjusted in this way is compared by one digital comparator 66a that outputs a high-level signal when the red signal Sb is at a higher level than the black-and-white signal Sa. Further, the gray level coefficient circuit 67
A circuit provided in consideration that a red image having a certain density or more should be copied as a black image,
The red signal Sb is compared with the reference value output from the gray level coefficient circuit 67 in the other digital comparator 66b, and in the case of a red signal having a certain density or more, a low level signal is output from the other comparator 66b. ing. And the AND circuit 68 has two comparators.
When the outputs of 66a and 66b both become high-level signals, a high-level signal for copying a red image is sent to the memory 69. The memory 69 accumulates image signals for one line output from the image sensors 54a and 54b, sends the signals to the drive circuit 70 at a predetermined timing, and
The LED array 7 is appropriately driven to blink based on the drive signal from the LED array 7. Through such a series of processing, a red signal component is extracted from the image signal.

On the other hand, the image signal generated by the image signal generation device 6 is also sent to the drive circuit 70 at a predetermined timing, and the drive signal from the drive circuit 70 causes the LED array 7 to be appropriately turned on and off. I have.

Further, in this embodiment, the coordinate reading device 8 is used.
6 and 7, the document cover 21
A digitizer layer 71 in which a large number of sense lines are attached in a rectangular shape, facing the upper side, a grid sheet 72 disposed on the digitizer layer 71, and an arbitrary point on the digitizer layer 71. And a cursor 73 as coordinate designation means for designating. When a predetermined image area of the document 2 is designated by the coordinate reading device 8, the document is moved along the document positioning portion 74 formed on the document cover 21 as shown in FIGS. After setting 2, the square sheet 72 is covered, and the diagonal positions P1 and P2 of the designated area M are indexed by the cursor 73, so that the electromagnetic induction between the cursor 73 and the digitizer layer 71 The positions P1 and P2 can be detected. When the image of the document 2 is copied after the coordinate reading process is completed, the document 2 is positioned and set at a predetermined position on the platen 20 as shown in FIG.
The document 2 may be suppressed at 21.

Further, the eraser 9 is provided at a stage subsequent to the first charging corotron 22, and as shown in FIG.
A long substrate 75 extending along the axial direction of the photosensitive drum 1
LED chips 76 are arranged at an interval of a predetermined pitch p (for example, 2 mm), a group of the LED chips 76 is surrounded by a reflecting mirror 77, and the light emitted from the LED chips 76 is condensed to a corresponding portion of the photosensitive drum 1. It has become.

As shown in FIG. 10, an edit mode selection switch 10 is provided on a part of a console panel 81 for copying operation, and includes nine edit modes shown in FIGS. 12 (a) to 12 (i). Various modes are switched and selected. The selected editing mode is displayed on the display section 82 on the console panel 81.
Is displayed. Incidentally, in FIG.
Is a start switch for starting a copying operation, and 84 is a copy image in this embodiment, which is limited to a two-color image of a black image and a red image. A color selection key used when a plurality of developing units are arranged and any of them can be selected, 85 is a numeric keypad for setting the number of copies, 86 is a number display unit for digitally displaying the number of copies. is there.

Further, the editing mode control device 11 is realized as one functional unit of the microprocessor shown in FIG.
In FIG. 11, reference numeral 91 denotes a CPU serving as the center of the microprocessor, 92 denotes a basic program for the copying process and an execution program for each editing mode.
The CPU 91 receives the position information of the image designation area from the coordinate reading device 8 via the AD converter 93, and operates the edit mode selection switch 10 Each program is executed according to the selected editing mode, and various devices necessary for the copying process and editing, specifically, the driving motor 4 of the optical filter 4
4. The signal processing circuit 56 for driving the LED array 7 and the image signal generating device 6, the eraser driving device 94 for the eraser 9, the charging driving devices 95 for the first charging corotron 22 and the second charging scorotron 23, the first and second charging devices. A developing driving device 96 for the developing devices 12 and 13;
The developing bias driving device 97 for setting the developing biases V1 and V2 of the first and second developing devices 12 and 13 is appropriately controlled.

Further, the first developing device 12 uses a two-component developer composed of a negatively charged black toner and a known carrier, and the latent image potential of the image portion is higher than that of the non-image portion. The set positive electrostatic latent image is positively developed. The second developing device 13 uses a two-component developer composed of a positively charged red toner and a magnetic carrier having a density of 4.0 g / cm ³ or less and magnetic powder dispersed in a resin binder. The negative electrostatic latent image formed by setting the latent image potential of the image portion lower than that of the non-image portion is negatively developed.

Next, the operation of the two-color color copying apparatus according to this embodiment will be described using a representative name editing mode as an example.

 First, typical editing modes include (a) two-color mode, (b) black image addition mode (original black single color image), (c) red image addition mode (same as above), (d) partial erasure mode (same as above), and (e). ) Partial color conversion mode (same as above) (f) Black addition mode (document red single color image) (g) Red image addition mode (same as above) (h) Partial erasure mode (same as above) (i) Partial color conversion mode (same as above) There are nine types (see FIGS. 12 (a) to (i)).

(A) Two-color mode (FIG. 12 (a)) In the apparatus according to this embodiment, the optical imaging system 3 and the LE
With the D array 7, two types of electrostatic latent images are formed. Here, the electrostatic latent image formed by the optical imaging system 3 is called a first latent image, and the electrostatic latent image formed by the LED array 7 is called a second latent image.

In this mode, a document 2 having a black image portion A (indicated by a dot portion) and a red image portion B (indicated by a hatched portion) on a white background portion is basically set as a copy target.
When the above mode is selected with the edit mode selection switch 10,
If the CPU 91 sets the red filter 41 in the optical path of the optical imaging system 3 and the platen 20 on which the original 2 is placed moves in the direction of arrow a in this state, the light guided by the optical imaging system 3 The image is guided to the photosensitive drum 1 through an optical filter 41 that transmits red light. As a result, the red light reflected by the red image (shown by oblique lines in FIG. 12 (a)) in the image on the original 2 is applied to the photosensitive drum 1 with an intensity close to the white light reflected from the white portion of the background. To reach. Therefore, according to the so-called positive writing, the electrostatic latent image corresponding to the red image is not formed (the charge is removed similarly to the background), and the first latent image corresponding to the image of the other color is formed. Become.

On the other hand, the image signal read by the image reading device 5 is extracted by the signal processing circuit 56 only as a signal corresponding to the red image, and the LED array 7 is driven according to the extracted signal, and the photosensitive drum 1 A second latent image corresponding to the red image is formed by so-called negative writing.

In this mode, the image signal generator 6, the coordinate reader 8 and the eraser 9 are not used.

More specifically, the photosensitive drum 1 rotates in the direction of arrow b in synchronization with the transport of the platen 20. Photosensitive drum 1
First, after the surface is cleaned by the pre-clean corotron 27 and the cleaner 26, an unnecessary charge is removed by the charge removing lamp 28. Next, the photosensitive drum 1 is primarily charged to about 1,500 V by the first charging corotron 22 (FIG. 13a). Thereafter, a first latent image (positive latent image) is formed by the optical imaging system 3, the red portion and the white portion H1 are neutralized to, for example, 600 to 650 V, and the black portion G1 has a surface potential of 1,200.
It is held at V (FIG. 13b). And the first developing device 12
After the developing bias V1 is set to 800 V, the positive latent image is positively developed with the black toner T1 of negative polarity to form a first toner image TG1 (FIG. 13c).

Next, DC is applied to the brit electrode of the second charged scorotron 23.
+ 500V, DC-4.5 to 5.0KV is applied to the wire. As a result, the potential of the toner image portion (solid image) formed on the photosensitive drum 1 in the first development step is charged to about 550V, and the potential of the non-image portion (background portion) is charged to 500V (FIG. 13d).
Note that a DC superimposed AC discharger may be used instead of the second charging scorotron 23.

Thereafter, a second latent image (negative latent image) is formed by the LED array 7. In this case, the portion corresponding to the red image G2 is neutralized, and its surface potential becomes 100 V (FIG. 13E). At this time, after setting the developing bias V2 to about 400 V, the second developing device 13 negatively develops the negative latent image using the positive-polarity red toner T2 to form a second toner image TG2 (the thirteenth image). Figure f).

In such a developing process, in the first and second developing processes, toners having different polarities are used, and one of the developing processes is a positive developing process and the other is a negative developing process. In the second development step, the second color toner is not mixed into the first toner image, and the color toner and the density are 4 g as the second developer. Since a two-component developer comprising a magnetic carrier of not more than / cm ³ is used, the magnetic brush is soft, and therefore, the first toner image is not scraped.

Then, the toner image TG using the black toner and the red toner
1, TG2 is formed on the photosensitive drum 1, and the polarity of the toner image is adjusted to a positive polarity by the pre-transfer treatment corotron 24 to which a voltage of DC + 6.0 KV is applied (FIG. 13g).

The copy sheet 14 is sent out from a sheet feed tray 29 by a sheet feed roll 30, and is sent to the transfer corotron 15 by a resist transfer roll 31. At this time, the transfer corotron 15 has AC + 10 KV superimposed on DC + 1.5 KV (f = 4
00 Hz), the two-color toner images TG1 and TG2 are collectively transferred to the copy sheet 14, and the copy sheet 14 is peeled off by the peeling corotron 25, and the fixing belt 33 is moved by the transport belt 32.
Conveyed toward. Finally, the copy sheet 14 that has been subjected to the fixing process by the fixing device 33 is discharged to a discharge tray 34.

(B) Black image addition mode (FIG. 12 (b)) In this mode, the original 2 is composed of a black monochromatic image (the same applies to each of the following modes (c) to (e)). The two-developing device 13 is replaced with a device using a two-component developer composed of a black toner having a positive polarity and an appropriate magnetic carrier.

First, when the above mode is selected by the edit mode selection switch 10, the CPU 91 causes the first charging corotron 22 to primary charge the surface potential of the photosensitive drum 1 to, for example, 1,000 V (first charging corotron 22).
14 Figure a). Next, the CPU 91 sets the light-blocking filter 43 in the optical path of the optical imaging system 3 and sets the first developing device 1
2, After deactivating the second charged scorotron 23, LED
The exposure process using the array 7 is performed, and the black original image G (the
12 (b) and the black added image G '(first
2A predetermined negative latent image corresponding to “C” in FIG. 2B (in this mode, the background portion H is about 800 V,
A latent image having a potential of about 100 V is formed (FIG. 14b). At this time, an area to which an image such as a character is to be added is designated in advance by the coordinate reading device 8, and the pattern of the black additional image G 'generated by the image signal generating means 6 is output to the designated area. And outputs an image signal based on the document image G read by the image reading device 5. After this,
When the developing bias V2 of the second developing device 13 is set to about 700 V and the negative development is performed, the latent image portions corresponding to the black original image G and the black additional image G 'are referred to as the toner image TG by the black toner T. Formed as TG '(FIG. 14c). When the transfer step is performed after the transfer pre-processing step,
A copy consisting of the black image-added image as shown in FIG. 12 (b) is obtained.

As another method for obtaining this mode, the optical imaging system 3
The toner image corresponding to the black original image G is obtained in the exposure process by the first developing device 12 and the developing process by the first developing device 12, while the black added image G ′ is A corresponding toner image may be obtained.

(C) Red image addition mode (FIG. 12 (c)) First, when the above mode is selected by the edit mode selection switch 10, the CPU 91 sets the surface potential of the photosensitive drum 1 to, for example, 1500V by the first charging corotron 22. Primary charging (No.
15 Figure a). Next, after setting the ND filter 42 in the optical path of the optical imaging system 3, the CPU 91 performs an exposure process using the optical imaging system 3, and performs the black original image G (“AB” in FIG. 12 (c)). A corresponding positive latent image (a latent image having a potential of about 1,200 V while the background portion H is about 600 V in this mode) is formed (FIG. 15B). Thereafter, when the developing bias V1 of the first developing device 12 is set to about 700 V and positive development is performed, a latent image portion corresponding to the black original image G is formed as a black toner image TG with the black toner T1. (FIG. 15c).

Thereafter, when the second charging step is performed in the second charging scorotron 23, the photosensitive drum 1 is charged substantially uniformly at about 500 to 600 V (FIG. 15d). Then, an area to which an image such as a character is to be added is designated in advance by the coordinate reading device 8, and the red added image G '(FIG. 12 (c)) generated by the image signal generating means 6 is designated in the designated area. (Corresponds to “C” in the middle)
Exposure process by the LED array 7 based on the pattern output is performed, and a predetermined negative latent image corresponding to the red additional image G '(in this mode, the background portion H is about 500 V,
A latent image having a potential of about 100 V) is formed (FIG. 15E). Thereafter, the developing bias V2 of the second developing device 13 is set to 400 V
When negative development is performed with the setting at about
The latent image part corresponding to is red toner image with red toner T2
Formed as TG '(FIG. 15f). When the transfer step is performed after the transfer pre-processing step, FIG. 12 (c)
A copy consisting of the red-image-added image shown in FIG.

(D) Partial erase mode (FIG. 12 (d)) First, when the above mode is selected by the edit mode selection switch 10, the CPU 91 sets the surface potential of the photosensitive drum 1 to, for example, 1,000 V by the first charging corotron 22. Charged (16th
If the range corresponding to the erased image Gb in the original image G (corresponding to “B” in FIG. 12D in this mode) is specified in advance by the coordinate reading device 8 in FIG. The eraser 9 is operated in accordance with the designated area, and the surface potential of the photosensitive drum 1 corresponding to the erased image Gb is set to about 200 V (the other part is about 800 V) (FIG. 16B).

Thereafter, the CPU 91 sets the ND in the optical path of the optical imaging system 3.
After setting the filter 42, an exposure step by the optical imaging system 3 is performed. At this time, since the surface potential of the photosensitive drum 1 at a location corresponding to the erased image Gb in the original image G has dropped to about 200 V, the residual image Ga (in this mode, “A” in FIG. A predetermined positive latent image (in this mode, the background portion H is 200 V,
A latent image of about 800 V is formed while Gb is about 100 V (FIG. 16c). Then, when the developing bias V1 of the first developing device 12 is set to about 300 V and the positive development is performed, a latent image portion corresponding to the residual image Ga is formed as a black toner image TG with the black toner T (second image). 16 Figure c).

Thereafter, the second charging step by the second charging scorotron 23, the exposing step by the LED array 7, and the developing step by the second developing device 13 are not performed. A copy consisting of the partially erased image as shown in FIG.

(E) Partial color conversion mode (FIG. 12 (e)) First, when the above mode is selected by the edit mode selection switch 10, the CPU 91 sets the surface potential of the photosensitive drum 1 to, for example, 1,500 V by the first charging corotron 22. Primary charging (17th
Then, a range corresponding to the color conversion image Gc in the original image G (corresponding to “B” in FIG. 12E in this mode) is specified in advance by the coordinate reading device 8 in FIG. When,
The eraser 9 is operated in accordance with the designated area, and the surface potential of the photosensitive drum 1 corresponding to the color conversion image Gc is set to about 600 V (the other part is about 1,200 V) (FIG. 17B).

Thereafter, the CPU 91 sets the ND in the optical path of the optical imaging system 3.
After setting the filter 42, an exposure step by the optical imaging system 3 is performed. At this time, the surface potential of the photosensitive drum 1 at a position corresponding to the color conversion image Gc in the original image G is 600 V
Therefore, a predetermined positive latent image (in this mode, the background portion H is 600 V and the color is a color) is placed at a position corresponding to the residual image Ga (corresponding to “A” in FIG. 12E in this mode). A latent image of about 1,200 V is formed while the converted image Ga is about 100 V (FIG. 17c). Then, when the positive bias is performed by setting the developing bias V1 of the first developing device 12 to about 700 V,
A latent image portion corresponding to the residual image Ga is formed as a black toner image TG1 by the black toner T1 (FIG. 17d).

Thereafter, a second charging step using the second charging scorotron 23 is performed to reduce the surface potential of the photosensitive drum 1 to approximately 600 to 7
It is uniformly charged to about 00V (FIG. 17e), and the coordinate reading device 8
Color conversion image at the location corresponding to the specified area from
When the exposure process using the LED array 7 based on Gc is performed,
A negative latent image corresponding to the color conversion image Gc (in this mode,
A latent image of about 100 V) is formed (FIG. 17f). In this state, when negative development is performed after the developing bias V2 of the second developing device 13 is set to about 500 V, the latent image portion corresponding to the color conversion image Gc becomes the red toner image TG2 with the red toner T2.
(FIG. 17g). Then, if the transfer step is performed after the transfer pre-processing step, a copy consisting of a color converted image in which a part of the black monochrome image original 2 is converted to red as shown in FIG. 12 (e) is obtained.

(F) Black image addition mode (FIG. 12 (f)) In this mode, the original 2 is composed of a monochromatic red image (the same applies to each of the modes (g) to (i) below). As one developing device 12, a developer using a negative red toner was used, and as a second developing device 13, a two-component developer including a positive black toner and an appropriate magnetic carrier was used. Replace with something.

First, when the above mode is selected by the edit mode selection switch 10, the CPU 91 causes the first charging corotron 22 to primary charge the surface potential of the photosensitive drum 1 to, for example, 1,500 V (second charging).
18 Figure a). Next, the CPU 91 sets the ND filter 42 in the optical path of the optical imaging system 3 and performs an exposure process using the optical imaging system 3 to obtain a red original image G (FIG. 12 (f)).
A positive latent image (a latent image having a potential of about 1,200 V while the background portion H is about 600 V in this mode) corresponding to "AB" in FIG. Then, when the positive developing is performed after the developing bias V1 of the first developing device 12 is set to 700 V, a latent image portion corresponding to the red original image G is formed as a red toner image TG1 with the red toner T1.

Thereafter, a second charging step is performed by the second charging scorotron 23 to uniformly charge the liquid to approximately 600 to 700 V (FIG. 18d).
An exposure process using the array 7 is performed. At this time, an area to which an image such as a character is to be added is designated in advance by the coordinate reading device 8, and the black added image G 'generated by the image signal generating means 6 (see FIG. If a pattern output corresponding to "C" in ()) is performed, a predetermined negative latent image (a latent image having a potential of about 100 V in this mode) corresponding to the black additional image G 'is formed (the second image). 18 Figure e). In this state, the developing bias V2 of the second developing device 13 is set to 500 V
When the negative development is performed with the setting at about
The latent image portion corresponding to is black toner image with black toner T2
Formed as TG2 (FIG. 18f). If the transfer step is performed after the pre-transfer processing step, a copy obtained by adding a black image to the monochromatic red original 2 is obtained.

(G) Red image addition mode (FIG. 12 (g)) First, when the above mode is selected by the edit mode selection switch 10, the CPU 91 causes the first charging corotron 22 to set the surface potential of the photosensitive drum 1 to, for example, 1,000V. Primary charging (No.
19 Figure a). Next, the CPU 91 sets the light-blocking filter 43 in the optical path of the optical imaging system 3 and sets the first developing device 1
2, After deactivating the second charged scorotron 23, LED
The exposure process using the array 7 is performed, and the red original image G (the
12 (g), corresponding to “AB”) and the red added image G ′ (first
2A predetermined negative latent image corresponding to “C” in FIG. 2G (in this mode, the background portion H is about 800 V,
A latent image having a potential of about 100 V is formed (FIG. 19b). At this time, a region to which an image such as a character is to be added is designated in advance by the coordinate reading device 8, and a pattern of the red additional image G ′ generated by the image signal generating means 6 is output to the designated region. At the same time, an image signal based on the red document image G read by the image reading device 5 is output. Thereafter, when the developing bias V2 of the second developing device 13 is set to about 700 V and negative development is performed, the latent image portions corresponding to the red original image G and the red added image G ' Formed as TG and TG '(FIG. 19c). Then, when the transfer step is performed after the transfer pre-processing step, a copy consisting of an image obtained by adding a red image to the red monochromatic original 2 as shown in FIG. 12 (g) is obtained.

(H) Partial erasing mode (FIG. 12 (h)) In this mode, the first developing device 12 is replaced with a device using a developer containing negative red toner.

First, when the above mode is selected by the edit mode selection switch 10, the CPU 91 primary charges the surface potential of the photosensitive drum 1 to, for example, 1,000 V by the first charging corotron 22 (20th).
(A), and a range corresponding to the erased image Gb in the original image G (corresponding to "B" in FIG. 12 (h) in this mode) is specified in advance by the coordinate reading device 8. The eraser 9 is operated in accordance with the designated area, and the surface potential of the photosensitive drum 1 corresponding to the erased image Gb is set to about 200 V (the other part is about 800 V) (FIG. 20B).

Thereafter, the CPU 91 sets the ND in the optical path of the optical imaging system 3.
After setting the filter 42, an exposure step by the optical imaging system 3 is performed. At this time, since the surface potential of the photosensitive drum 1 at a location corresponding to the erased image Gb in the original image G has dropped to about 200 V, the residual image Ga (in this mode, “A” in FIG. A predetermined positive latent image (in this mode, the background portion H is 200 V,
A latent image of about 800 V is formed while Gb is about 100 V (FIG. 20c). Then, when the developing bias V1 of the first developing device 12 is set to about 300 V and the positive development is performed, a latent image portion corresponding to the residual image Ga is formed as a black toner image TG with the red toner T (the second image). 20 Figure d).

Thereafter, the second charging step by the second charging scorotron 23, the exposing step by the LED array 7, and the developing step by the second developing device 13 are not performed. As shown in FIG. 9G, a copy consisting of an image partially erased from the monochromatic red original 2 is obtained.

(I) Partial color conversion mode (FIG. 12 (i)) First, when the above-mentioned mode is selected by the edit mode selection switch 10, the CPU 91 sets the surface potential of the photosensitive drum 1 to, for example, 1,500V by the first charging corotron 22. Primary charging (21st
Then, a range corresponding to the residual image Ga in the original image G (corresponding to “B” in FIG. 12 (i) in this mode) is specified in advance by the coordinate reading device 8. Then, the eraser 9 is operated in accordance with the designated area, and the surface potential of the photosensitive drum 1 corresponding to the residual image Ga is set to about 600 V (the other part is about 1,200 V) (FIG. 21B).

Thereafter, the CPU 91 sets the ND in the optical path of the optical imaging system 3.
After setting the filter 42, an exposure step by the optical imaging system 3 is performed. At this time, since the surface potential of the photosensitive drum 1 at a position corresponding to the residual image Gc in the original image G has dropped to about 600 V, the color conversion image Ga (in this mode, “ A predetermined positive latent image (a latent image having a background portion H of about 600 V and a residual image Gc of about 100 V in comparison with the remaining image Gc of about 800 V in this mode) is formed at a location corresponding to A "(FIG. 21c). ). Then, when the developing bias V1 of the first developing device 12 is set to about 700 V and positive development is performed, a latent image portion corresponding to the color conversion image Gc is formed as a black toner image TG1 with the black toner T1 ( FIG. 21 d).

Thereafter, a second charging step by the second charging scorotron 23 is performed to uniformly charge the surface potential of the photosensitive drum 1 at approximately 600 to 700 V (FIG. 21E), and the photosensitive drum 1 corresponds to the designated area from the coordinate reading device 8. LED based on the residual image Ga above
When the exposure process using the array 7 is performed, the residual image Ga
Negative latent image (latent image of about 100V in this mode)
Is formed (FIG. 21f). In this state, when negative development is performed after setting the developing bias V2 of the second developing device 13 to about 500 V, a latent image portion corresponding to the residual image Ga is formed as a red toner image TG2 with the red toner T2. (FIG. 21g). Then, if the transfer step is performed after the transfer pre-processing step, a copy consisting of a color conversion image in which a part of the red monochromatic image original 2 is converted to black as shown in FIG. 12 (i) is obtained.

Each of the above-mentioned editing modes is a typical one, and other appropriate editing can be performed. The editing modes, red erasing mode, all black mode, black erasing mode, all red mode, monochrome black mode, monochrome red mode, black inversion mode, and red inversion mode in FIGS. 22 (a) to (h) are described below. 3 shows a simple image editing example that can be performed without using the image signal generating device 6, the coordinate reading device 8, and the eraser 9.

Further, as a modified example of the above-described embodiment, for example, as the image reading device 5, for example, an ND filter for adjusting the incident light level may be inserted in front of one of the image sensors 54a, as shown in FIG. As described above, the dichroic mirror 57 may be used instead of the half mirror 53 and the red filter 55. In the above embodiment, the image signal is extracted using the black-and-white image sensor 54.
The present invention is not limited to this, and if a slight decrease in sensitivity is not a problem, a one-dimensional CCD solid-state imaging device including a red, green, blue or cyan, magenta, and yellow filter is alternately arranged on the light receiving surface. A so-called color image sensor that is arranged may be used. As the signal processing in this case, for example, RGB (red, green, blue) image signals converted by the color image sensor 5 are compared pixel by pixel to determine whether or not the pixel is red. If judged, LED
The corresponding LED of the array 7 may be turned on to remove the charge on the charged photosensitive drum 1, or a method of addressing the color space, specifically, the intensity of the red component signal for one pixel may be used. Take the X axis and the green component signal on the Y axis,
The position coordinates may be obtained, and if the position coordinates are in a region corresponding to a predetermined red component, the position may be determined to be red, and if the position coordinates are in other regions, it may be determined to be not red.

FIG. 24 shows a modification of the overall structure of the two-color copying machine.

In this modification, an exposure lamp 35, four mirrors 36
(Specifically, 36a to 36d) and the electrostatic latent image based on the exposure process of the optical imaging system 3 including the imaging lens 37 are formed after the electrostatic latent image based on the exposure process of the LED array 7. It has become.

That is, first, an electrostatic latent image based on the LED array 7 is negatively written on the photosensitive drum 1 uniformly charged by the first charging corotron 22. Then, the first developing device (using a red toner having a positive polarity) 12 reversely develops the toner using the red toner having a positive polarity.

Thereafter, unlike the embodiment, the electrostatic latent image by positive writing is formed by the optical imaging system 3 by omitting the recharging of the photosensitive drum 1 and the second developing device (shown in the embodiment with the black toner of negative polarity) 13) develops the electrostatic latent image positively with a negative black toner.

In this way, two-color toner images are formed on the photosensitive drum 1, and various kinds of image editing similar to the embodiment can be performed.

[Effects of the Invention] As described above, according to the two-color copying machine according to the present invention, one of the two systems of latent image forming means is an optical imaging system, so that the cost of the apparatus can be reduced. While
Good black image quality can be maintained.

Also, devising a method of forming and developing a two-system latent image, and further, as a developer used in the second developing means,
By using a two-component developer comprising a second color toner and a magnetic carrier having a density of 4 g / cm ³ or less, scraping of a toner image and mixing of toner are avoided,
In addition, since an appropriately edited latent image can be formed from the original image and an image other than the original, the image information is not limited to the image information in the original while maintaining good two-color image quality of the copy. It is possible to diversify editing.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a two-color color copying apparatus according to the present invention, FIG. 2 is a schematic perspective view showing one embodiment of a two-color color copying apparatus according to the present invention, and FIG. FIG. 4 is an explanatory diagram showing details of an optical filter used in the example, FIG. 4 is an explanatory diagram showing a specific example of an image reading device used in the embodiment, and FIG. Block diagram showing details of the signal processing circuit of FIG.
FIG. 7 and FIG. 7 are explanatory views showing the structure of a document cover portion used in the embodiment, FIG. 8 is an explanatory view showing the principle of a coordinate reading device incorporated in the document cover, and FIG. 9 is used in the embodiment. FIG. 10 is a perspective view showing details of the eraser, FIG. 10 is an explanatory diagram showing details of an edit mode selection switch used in the embodiment, FIG. 11 is a block diagram showing an example of an edit mode control device used in the embodiment, FIG. 12 (a) to 12 (i) are explanatory views showing an image editing mode performed in the two-color color copying apparatus according to the embodiment. FIGS. 13 to 21 are FIGS. 12 (a) to 12 (i). FIGS. 22 (a) to (h) are explanatory diagrams showing another example of the image editing mode performed by the two-color copying machine according to the embodiment. FIG. 23 is an explanatory view showing a modification of the image reading apparatus, and FIG. Modification of the entire system of two-color copying apparatus according to the invention is a schematic diagram illustrating an. [Explanation of Symbols] 1... Photosensitive drum (photoreceptor) 2... Original 3... Optical imaging system 4... Optical filter (color separation means) 5... Image reading device (means) 6. Device (means) 7 LED array (light output means) 8 Coordinate reader (image area designating means) 9 Eraser (static elimination means) 10 Edit mode selection switch (means) 11 Edit mode control Apparatus (means) 12 First developing unit (first developing unit) 13 Second developing unit (second developing unit) 14 Copy sheet 15 Transfer corotron (transfer unit)

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location G03G 15/01 117 G03G 21/00 382 15/04 111 9/08 361 15/36 9/10 ( 72) Inventor Koji Adachi 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. JP-A-58-43481 (JP, A) JP-A-56-39558 (JP, A) JP-A-61-140953 (JP, A) JP-A-56-87060 (JP, A) JP-A-60-244957 (JP) , A) JP-A-60-147749 (JP, A) JP-A-62-6741 (JP, U)

Claims (1)

(57) [Claims] A photosensitive member for forming a latent image; and an optical imaging system for guiding a light image of a document to the photosensitive member to form a first positive or negative latent image. 3), color separation means (4) selectively disposed in the optical path of the optical imaging system (3), and image reading means for reading an original (2) image and converting it into an electric image signal (5) an image signal generating means (6) for outputting a predetermined pattern image as an electric image signal; and at least one of the image reading means (5) and the image signal generating means (6). An optical output means (7) for forming a second latent image in a state in which the first latent image is inverted on the photosensitive member (1) based on the image signal; An image area designating means (8) for designating the first or second latent image; (9) for erasing the electric charge in the area designated by the user, an edit mode selecting means (10) for selecting an image editing mode of the original, and a second mode according to the mode selected by the edit mode selecting means (10). Editing mode control means (11) for controlling each latent image forming means (4, 7, 9 etc.) to form first and second latent images; and the first and second latent images with a first color toner. A first developing means (12) for positively or negatively developing the previously formed latent image of the image; a second color toner having a charging characteristic different from that of the first color toner and a density of 4 g / cm ³ or less; A two-component developer comprising a magnetic carrier of the second type and a latent image formed later of the first and second latent images with the second color toner, which is different from the first developing means (12). Developing means (13) for developing with
Transfer means (15) for transferring each color toner image formed on the photoreceptor (1) to the copy sheet (14) side after the development step by the first and second developing means (12, 13) is completed; A two-color copying machine comprising: