JPH0511564A - Copying device - Google Patents

Abstract

PURPOSE:To prevent an image at the leading edge of a transfer material from being transferred again by detecting and calculating the color, the position and the area of a specified area in an original, and then performing copying from the area closer to the leading edge in the feeding direction of the transfer material or from the area having a smaller area. CONSTITUTION:After the color, the position and the area of a place obtained by specifying the area of the original are detected and calculated, a distance between the leading edge of the transfer material and the specified area closest to the leading edge in the feeding direction of the transfer material is compared with a distance between the leading edge of the transfer material and the other specified area. When a difference between the distances is >=2cm, developing devices 10a-10d which develop the color of the specified area closest to the leading edge in the feeding direction of the transfer material are moved to a developing area opposed to a photosensitive drum 6 by a control part CONT, and copying is performed. When the difference between the distances is <2cm, the area of the specified area closest to the leading edge in the feeding direction of the transfer material is compared with the area of the other specified area, and in the case that a difference between the areas is >=10cm<2>, the developing devices 10a-10d which develop the color of the specified area having the smaller area are moved to the area opposed to the photosensitive drum 6 in the same way, and the copying is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sequentially and automatically repeats the copying process of latent image formation-development-transfer-fixing for each designated area in a document, and at least two or more colors are formed on one transfer material. The present invention relates to a copying apparatus capable of forming a copied image.

[0002]

2. Description of the Related Art Conventionally, a copying apparatus for making a copy having an image of a different color for each color area on one transfer material has been proposed and put on the market. In such a copying apparatus, the copying process of latent image formation-developing-transfer-fixing is sequentially and automatically repeated for each designated area in a document to form a copy image of at least two colors on one transfer material. To do.

In a conventional apparatus for obtaining a copy in such a copying process, after detecting the color and position of a designated area in a document, (1) it is installed at a position where the time required for development is the shortest. The copying process is carried out from the color of the developer possessed by the developing device, or (2) the copying process is carried out from the designated color in the region closest to the front end of the transfer material in the conveying direction, whereby a multi-color copy is made. Often get.

[0004]

However, the present inventors have found that "retransfer", which reduces image quality in this type of copying apparatus, that is, "unfixed image transferred from an image carrier to a transfer material is re-transferred". As a result of research and experiment regarding "the phenomenon of being transferred to an image carrier", it was found that there is the following tendency regarding retransfer. The larger the curl amount of the transfer material, the easier the retransfer. The area closer to the tip of the transfer material is easier to retransfer. The smaller the area of the designated region (the smaller the amount of toner on the transfer material), the easier the retransfer. Further, the curl amount of the transfer material increases every time the transfer material passes through the fixing device.

On the other hand, in the conventional copying apparatus,
(1) When performing the copying process from the color of the developer included in the developing device installed at the position where the time required for development is the shortest, the above points are not taken into consideration. Retransfer of the color image designated in the area at the front end of the transfer material is likely to occur.

Further, in the conventional copying apparatus, (2) the above point is not taken into consideration when performing the copying process from the designated color in the area closest to the front end in the conveying direction of the transfer material. In multiple transfer, retransfer of a color image in a region having a small area at the front end of the transfer material is likely to occur.

As described above, the conventional copying apparatus has the drawbacks described in (1) or (2) above.

Therefore, an object of the present invention is, in particular, a transfer material capable of preventing retransfer of the image at the leading end of the transfer material, improving the image quality, and increasing the copying speed. Another object of the present invention is to provide a copying apparatus for making a copy having an image of a different color for each color area.

[0009]

The above object can be achieved by a copying apparatus according to the present invention. In summary, the present invention sequentially and automatically repeats the copying process of latent image formation-developing-transfer-fixing for each designated area in a document to form a copy image of at least two colors on one transfer material. In a possible copying apparatus, the color, position, and area of a designated area in the original are detected and calculated, respectively, and the leading edge of the designated area is closest to the leading edge of the transfer material in the feeding direction. Is compared with the distance from the tip position of the other designated area to the leading edge of the transfer material in the conveying direction. If all the differences in distance are 2 cm or more, the closest designation from the leading edge of the transfer material in the conveying direction is designated. The copying process is performed sequentially from the detected colors in the specified area, and the distance from the tip position of the specified area that is closest to the transfer material's leading edge to the transfer material's leading edge and the other specified area. Transfer from the tip position of If the difference in the distance to the leading end of the transfer direction is less than 2 cm, the copying process is performed from the designated color with the smaller area of the designated region, and the designated closest to the leading end of the transfer material in the feeding direction. The difference between the distance from the leading edge of the area to the leading edge of the transfer material in the transport direction and the distance from the leading edge of the other designated area to the leading edge of the transfer material in the transport direction is less than 2 cm, and the difference in area is 10 cm ^2. If it is less than the specified value, the copying apparatus sequentially performs the copying process from the color of the developer filled in the developing device at the position where the time required for the development is the shortest among the designated colors. According to another aspect, the developing device located at the position where the time required for development is the shortest is filled in the designated region which is located at the rear end of the transfer material in the rear end of 10 cm from the front end in the conveying direction. The copying process is performed in order from the color of the developer that is present, and when a thick transfer material of 80 g / m ² or more is used, the developer is placed at the position where the time required for development is the shortest. The copying process is sequentially performed from the color of the developer.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The copying apparatus of the present invention will be described in more detail below with reference to the drawings.

FIG. 1 shows an electrophotographic copying apparatus which is an embodiment of the present invention. In this embodiment, an image carrier 6 such as an electrophotographic photosensitive drum is rotatably arranged in the arrow direction. The platen glass 1 is arranged above the photosensitive drum 6,
A color original is placed on the original glass 1 at a predetermined position. A document placed on the platen glass 1 is exposed by a document irradiation lamp composed of, for example, a halogen lamp, and reflected light from the document is reciprocated in the main scanning direction by the scanning mirrors 3a to 3c constituting the optical scanning unit. CC while moving
It is led to the D unit 4.

The CCD unit 4 has an image forming lens 4a, and an image pickup device 4b and a non-filter image pickup device 4 which are, for example, CCDs for color separation of reflected light from a document.
It is composed of c and the like. Further, the image pickup device 4b and the non-filter image pickup device 4c constitute an area detecting means, and detect a specific line drawing image area in the color original placed on the original table glass 1. On the other hand, the reflected light imaged by the imaging lens 4 a is irradiated onto the photosensitive drum 6 by the folding mirror 5.

Further, around the photosensitive drum 6, a pre-exposure lamp 7 for removing the electric charge of the photosensitive drum 6 in preparation for image formation, a charger 8 for uniformly charging the photosensitive drum 6, and an eraser as an eraser means. The unit 9 is arranged. The eraser unit 9 is composed of, for example, a semiconductor laser or the like, and of the photosensitive drum 6 corresponding to the line image area of a specific color detected by the image sensor 4b and the non-filter image sensor 4c in parallel with the document exposure of the optical scanning unit. The image area is selectively irradiated with a laser beam based on the number of times of multiple transfer to erase the formed electrostatic latent image. If this erasing process is performed in parallel with document exposure, a desired area can be erased without performing prescanning.

The latent image formed on the photosensitive drum 6 having the above-described structure is converted into a visible image (toner image) by the developing device. In this embodiment, a fixed developing device 10a is arranged and contains, for example, black toner. Further, a device 11 for accommodating a plurality of developing devices and for delivering the developing devices to a developing area facing the photosensitive drum 6 for developing the latent image on the photosensitive drum 6 is provided. Developing devices 10b and 10 filled with a developer that develops a developing color such as blue, green, or the like.
c, 10d, etc. are stored.

On the other hand, the sheet-shaped transfer material is used in the paper feed cassette 1.
2a, 12b, and each paper feed roller 13a,
The transfer material is fed into the apparatus by driving 13b, is temporarily stopped at the position where the registration roller 14 is disposed, and is re-fed at the timing of the writing position with the image formed on the photosensitive drum 6. The toner image on the photosensitive drum 6 is transferred to the transfer material fed by the transfer charger 15. After the transfer operation is completed, the transfer material is transferred to the photosensitive drum 6 by the separation charger 16.
And is conveyed to the fixing device 18 by the conveyor belt 17.

A flapper 19 is arranged on the downstream side of the fixing device 18, and the transfer path of the transfer material, for which the fixing process has been completed, is directed toward either the discharge tray 20 or the intermediate tray 22. Control. The fixed transfer material controlled in the direction of the intermediate tray 22 is fed by the feeding rollers 21a to 21.
At d, the sheets are inverted (multiplexed) or non-inverted (double-sided) and fed to the intermediate tray 22. The transfer material placed on the intermediate tray 22 is again conveyed by the re-feed roller 23 to the position where the registration roller 14 is arranged via the conveyance path 24.

According to this embodiment, an exposure shutter 25 serving as shutter means is provided, and the exposure shutter 25 is
Image light scanned by the folding mirror 5 is picked up by the image pickup device 4
b, the arrival of the reflected light of the original, which is scanned corresponding to the line image area of the specific color detected by the non-filter image sensor 4c and the photosensitive drum 6, is controlled. In the present embodiment, the image control and color conversion development processing are generally controlled based on the control program stored in the ROM provided in the control unit CONT which also serves as the development control means.

FIG. 2 shows an automatic color image multiple transfer processing procedure carried out in accordance with the present invention in the copying machine having the above-mentioned structure.
~ It demonstrates based on the flowchart shown in FIG. The procedure of each step in the flowchart is stored in the ROM provided in the control unit CONT that controls the copying apparatus.

When the copy key is pressed in the copying machine, the exposure of the original document starts and scanning of the original document starts (step 1). After detecting and calculating the color, position, and area of the designated area of the original (step 2), the distance from the leading edge of the transfer material closest to the leading edge of the transfer material in the conveying direction and the transfer of other area designation The distance from the tip of the material is compared (step 3).

When the difference in distance is 2 cm or more (FIG. 3): The developing device for developing the designated color in the region closest to the leading end of the transfer material in the transport direction is moved to the developing region facing the photosensitive drum by the control unit CONT. Then (step 4, step 5), a copy process, that is, a copying process is performed for the color (step 6). Next, the area designation after the copying process is deleted from the image data (step 7), and it is judged whether or not the remaining area designation exists (step 8). If so, return to step 3.

When the difference in distance is less than 2 cm (FIG. 4): The area designated closest to the front end of the transfer material in the conveying direction is compared with the area designated in another area (step 9), and the difference in area is 10 cm. When it is ² or more, the developing unit for developing the color of the area having the smaller area is moved to the developing area facing the photosensitive drum by the control unit CONT (step 1
0, step 11) and the copying process for that color is performed (step 12). Next, the area designation after the copying process is deleted from the image data (step 13), and it is judged whether or not the remaining area designation exists (step 14). If so, return to step 3. 10 cm difference in area
^In the case of ² or less, the developing device that requires the shortest development time is selected (step 15), and the developing device is moved to the developing area facing the photosensitive drum by the control unit CONT (step 16). A copying process is performed for the color of the developer filled in the selected developing device (step 17), and the area designation after the copying process is deleted from the image data (step 18). It is judged whether there is a remaining area designation (step 19), and if there is, a step 3
Return to. If not, the copying process ends.

By the above-mentioned operations, the copying process is performed by sequentially performing the copying process from a region closer to the leading end of the transfer material in the conveying direction and a region having a smaller area.

The curl of the transfer material does not affect retransfer so much with respect to the designation of the area located 10 cm or more from the front end in the conveying direction of the transfer material to the rear end side. Therefore, in order to increase the copying speed (copy speed), it is better to start the development from the developing device housed in the position where the time required for the development is the shortest.

FIG. 5 shows the transfer material 10c from the front end in the conveying direction.
9 is a flowchart illustrating an automatic color image multiple transfer processing procedure for designation of an area within m and over 10 cm.

Similar to the first embodiment described above, when the copy key is pressed, the exposure of the original document starts and scanning of the original document starts (step 1). After detecting and calculating the color, position and area of the designated area of the document (step 2), it is determined whether the area is designated within 10 cm from the leading end of the transfer material in the conveying direction (step 3). If the area is designated, the procedure from step 4 onward in the first embodiment is similarly repeated. If the area is not designated, the developing device having the shortest development time is selected (step 5), and the selected developing device is moved to the developing area facing the photosensitive drum by the control unit CONT (step 6). The copying process is performed for the color of the developer filled in the selected developing device (step 7), and the area designation after the copying process is deleted from the image data (step 8). next,
It is judged whether or not there is another area designation (step 9). If it exists, the process returns to (step 5). After that, each step of (step 5)-(step 6)-(step 7)-(step 8)-(step 9) is repeated, and the copy operation is ended when the area is no longer designated.

If a thick transfer material having a weight of 80 g / m ² or more is used as the transfer material, the transfer material and the photosensitive drum can be easily separated due to the weight of the transfer material, so that the area designation will be repeated no matter where it is. Transcription is unlikely to occur. Therefore, when a thick transfer material of 80 g / m ² or more is used as the transfer material, the automatic color image multiple transfer processing procedure is changed by a changeover switch, etc. The copying process is sequentially performed from the color of the developer filled in the developing device at the position where the length is shortened. This procedure is sequentially repeated, and the copy operation ends when the area is no longer specified.

[0027]

As described above, in the copying apparatus according to the present invention, after detecting and calculating the color, position, and area of the designated area in the document, the area closer to the front end of the transfer material in the conveying direction is detected. Further, since the copying process is performed from a region having a smaller area, it is possible to prevent re-transfer of the image of the front end portion of the transfer material, and always obtain a high quality image. Further, according to the present invention, in order to specify the area of 10 cm or more from the front end of the transfer material in the conveying direction, the development is performed using the developing device located at the position where the time required for the development is the shortest, so the copying speed is increased. The effect of being able to do so can also be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a copying apparatus according to the present invention.

FIG. 2 is a flowchart illustrating an automatic color image multiple transfer processing procedure of an embodiment in the copying apparatus of the present invention.

FIG. 3 is a flowchart illustrating an automatic color image multiple transfer processing procedure of another embodiment in the copying apparatus of the present invention.

FIG. 4 is a flowchart illustrating an automatic color image multiple transfer processing procedure of another embodiment in the copying apparatus of the present invention.

FIG. 5 is a flowchart illustrating an automatic color image multiple transfer processing procedure of another embodiment in the copying apparatus of the present invention.

[Explanation of symbols]

1 Platen glass 4 CCD unit 6 Image carrier (photosensitive drum) 8 charger 10a to 10d developing device 15 Transfer charger 18 Fixer

Claims (3)

[Claims] 1. A latent image is formed for each designated area in a document.
The copying process of development-transfer-fixing is automatically repeated in sequence.
In a copying apparatus capable of forming a copy image of at least two colors on one transfer material, the color of a specified area in the original,
The position and area are detected and calculated respectively, and the distance from the tip position of the designated area closest to the tip of the transfer material in the conveying direction to the tip of the transfer material in the conveying direction and the tip position of the other designated area are transferred. When the distances to the leading end of the material in the conveying direction are compared, and if all the differences in distance are 2 cm or more, the copying process is sequentially performed from the detected color of the designated area closest to the leading end of the transferring material in the conveying direction. The difference between the distance from the tip position of the designated area, which is the closest to the tip of the material in the transport direction, to the tip of the transfer material in the transport direction, and the distance from the tip position of the other designated area to the tip of the transfer material in the transport direction If it is less than 2 cm, the copying process is performed from the specified color with the smaller area of the specified area,
The distance from the tip position of the designated area closest to the tip of the transfer material in the conveying direction to the tip of the transfer material in the conveying direction and the distance from the tip position of the other designated area to the tip of the transfer material in the conveying direction. The difference is less than 2 cm, and the difference in area is 1
If it is less than 0 cm ² , the copying machine is characterized in that the copying process is sequentially performed from the color of the developer filled in the developing device at the position where the developing time is the shortest among the designated colors. 2. The developer filled in the developing device at the position where the time required for development is the shortest for the specified region located at the rear end of more than 10 cm from the front end of the transfer material in the conveying direction. 2. The copying apparatus according to claim 1, wherein the copying process is sequentially performed from the color. 3. When a transfer material of 80 g / m ² or more is used, the copying process is sequentially performed from the color of the developer filled in the developing device at the position where the time required for development is the shortest. The copying apparatus according to claim 1.