JPH04149469A - Image forming device - Google Patents

Abstract

PURPOSE:To perform divided-printing processing at a high speed by controlling so that a recording medium may be ejected in order from the recording medium where an image is formed by an image forming means which is close to an ejection part. CONSTITUTION:This device is provided with the image forming parts 302, 303, 304 and 305 for respective colors such as magenta (M), cyan (C), yellow (Y) and black (K) and controlled so that the recording medium may be ejected in order from the recording medium P1 where the image is formed by the image forming means 305 which is close to the ejection part. When the sum of the length L of the transfer members P1-P4 and a distance G between the members P1-P4 is longer than a distance W between the image forming parts 302-305, the image of K, the image of Y, the image of M, and the image of C are orderly formed on the fed members P1, P2, P3 and P4 when the P1, the P2, the P3 and the P4 reach the parts 305, 304, 303 and 302, respectively. Thus, the recording media P1-P4 are carried in advance and an acting time is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus including a plurality of image forming sections, and particularly to a color image forming apparatus.

[Prior Art] A color copying apparatus is configured to form an image by overlapping three colors of cyan, magenta, and yellow, or four colors including black. In recent years, digital image processing has been proposed to form images with better reproducibility. By incorporating digital image processing, it is possible to not only improve the image but also realize various functions such as color conversion and cropping.

[Problems to be Solved by the Invention] As described above, color copying apparatuses are generally capable of performing a variety of image processing, one of which is a color separation function. This outputs images to independent recording media for each output color, like a block used for printing. However, in the color separation function, since images are formed on separate recording media for each color, there is a problem in that it takes longer to output than normal output in which images are printed overlappingly on the same medium.

In view of the above points, it is an object of the present invention to provide an image forming apparatus that can perform color separation processing at high speed.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention includes a plurality of image forming means arranged in order from a discharge section from which a recording medium on which an image has been formed is discharged, and each image forming means is provided with a plurality of image forming means. The apparatus forms an image on an independent recording medium, and has means for controlling the recording medium to be discharged in order from the recording medium on which an image has been formed by the image forming means near the discharge section.

[Embodiment] FIG. 1 shows a cross section of a digital color copying apparatus embodying the present invention. In the same figure, 100 is an operation section,
It is provided to set the paper size on which an image is to be formed and the separation mode. 101 is a reader unit that reads the original;
02 is a printer section that outputs a copy based on the read image signal, 301 is a polygon scanner that scans a photosensitive drum with a laser beam, and 302 is a magenta (M) image forming section at the first stage; Cyan (C) in configuration
), yellow (Y), and black (K) are shown by 303.304.305.

In the image forming unit 302, 318 is a photosensitive drum that forms a latent image by exposure to laser light, and 313 is a developing device that develops toner on the drum 318.
3, 314 is a sleeve that performs toner development by applying a developing bias, 315 is a primary charger that charges the photosensitive drum 318 to a desired potential, and 317 cleans the surface of the drum 318 after transfer. It is a cleaner and 316
330 is an auxiliary charger that eliminates static electricity from the surface of the drum 318 cleaned by the cleaner 317 so that a good charge can be obtained in the primary charger 315, and 330 is a pre-exposure lamp that erases the residual charge on the drum 318. 319 is a transfer charger that generates discharge from the back side of the transfer belt 306 and transfers the toner image on the drum 318 to a transfer member.

309.310 is a cassette that stores the transfer member,
308 is a paper feed unit that supplies the transfer member from the cassette 309 and 310; 311 is an adsorption charger that attracts the transfer member fed by the paper feed unit to the transfer belt 306; and 312 is a charger that attracts the transfer member fed by the paper feed unit to the transfer belt 306; This transfer belt roller is used for charging the transfer member on the transfer belt 306 by attracting and charging the transfer member in a pair with the attracting charger 311 at the same time.

Reference numeral 324 designates a charge eliminating charger for facilitating separation of the transfer member from the transfer belt 306, reference numeral 325 designates a peeling charger for preventing image disturbance due to peeling discharge when the transfer member is separated from the transfer belt, and 326, 327 322 and 323 are pre-fixing chargers that supplement the adsorption force of toner on the transfer member after separation and prevent image disturbance; 322 and 323 are transfer belts 306;
328 is a transfer belt neutralization charger for eliminating static electricity and electrostatically initializing the transfer belt 306;
This is a belt cleaner that removes dirt from 06.

A fixing device 307 is separated from the transfer belt 306 and heat-fixes the toner image on the transfer member, which has been recharged by pre-fixing chargers 326 and 327, onto the transfer member.

329 is a paper leading edge sensor that detects the leading edge of the transfer member fed onto the transfer belt by the paper feeding unit 308; a detection signal from the paper leading edge sensor is sent from the printer unit to the reader unit; It is used as a sub-scanning synchronization signal when sending a video signal to the printer section. Reference numeral 400 denotes a control circuit for controlling a conveyance motor and timing for reading image data from an image memory, which will be described later in FIG.

FIG. 2 shows the image processing system of the reader section mentioned above. A line sensor 201 outputs R, G, and B data in this embodiment. 202 is an A/D converter, 203 is a shading correction circuit, and 204 is an image memory. In this embodiment, data of an A3 size color document can be stored as color image data. When storing the image data of a color original, the RlG and B data are separated into brightness and chromaticity, for example, a.

Image data can be stored in a memory with a smaller capacity by compressing the image data after converting it into b data and decompressing the data when reading it from the memory. 205C,
205M, 205Y, 205 have LOG conversion circuit,
206C, 206Y, 206Y, 206 has a masking/UCR circuit, 207C, 207M, 207Y, 2
07 has a γ correction circuit, 208C, 208M, 208Y,
208 is a laser driver. Line sensor 201
The image signal read by is converted into a digital signal by an A/D converter 202, and then sent to a shading correction circuit 203.
After undergoing shading correction, the image is stored in the image memory 204. C, M, Y, K from image memory 204
The signals for the image forming section are extracted and processed separately.To explain the C signal, the LOG conversion circuit 2
It is converted into a density signal at 05C, and subjected to masking processing and undercolor removal at a masking/UCR circuit 206C to become a C image signal. Thereafter, the sensitivity of the photosensitive drum of the printer section is corrected by the γ correction circuit 207C, and the laser driver 20
A semiconductor laser is driven at 8C to form a C latent image on the photosensitive drum. Since the processing is similar for the signals MlY and MlY, a description thereof will be omitted.

Next, the operation when performing the separation function by the apparatus of this embodiment will be described. When performing color separation, the four transfer members PL, P2, P3, and P4 are placed in the cassette 309 or 31.
Supply from 0. Images are formed on each of the four transfer members independently by image forming sections 302, 303, 304, and 305, and a monochromatic image is formed on each of CSM and Y.

When the sum of the length of the transfer member and the distance G between the transfer members is longer than the distance W between the image forming sections, when Pl reaches 305 for the fed transfer members PiSP2, P3, and P4. K image formation is performed, then Y image formation is performed when P2 reaches 304, then M image formation is performed when P3 reaches 303, and C image formation is performed when P4 reaches 302. control to ensure that That is, control is performed to form images in order from the image forming section on the discharge side. FIG. 3 shows the positional relationship between the image forming section and the transfer member. As shown in FIG. 3(a), when the transfer member PI reaches the image forming section 305, the image forming operation is started for the first time.

At this time, P2, P3, and P4 have not yet reached their respective image forming units 304, 303, and 302. The image formation ends when the image is formed on the last transfer member P4 at 302, and then the sheet is ejected through the fixing device.

Next, if the sum of the length L of the transfer member and the distance G between the transfer members is shorter than the distance W between the image forming sections, as shown in FIG. 3(b).
As shown in FIG. 2, the transferred transfer member PL is fed.

Among P2, P3, and P4, before Pl, P2, and P3 reach their respective image forming units 305.304.303, P4
reaches the image forming unit 302. P4 is the image forming section 30
2 and starts image formation, P3 reaches the image forming section 303, and then P2 reaches 304 and Pl reaches 305.
are reached one after another to form an image.

By configuring the image forming order as described above and controlling the operation of the image forming section, the transfer member PI is transferred to the image forming section 305.
or until the transfer member P4 reaches the image forming section 302.
The reader section can perform a series of initial operations such as shading during the time it takes to reach , and the total time for image formation is shortened. If the order of the colors in which images are formed is reversed, the printer section will have to wait until the initial operation of the reader section is completed, so that it will take more time to operate than according to the present invention.

Switching between the two operations shown in FIGS. 3(a) and 3(b) described above is performed by the control circuit 400 in response to the operation of the operating unit 100.

[Other Embodiments] The present embodiment described above is not limited to the color separation function of a color copying apparatus, but can be similarly applied to a case where each image forming section outputs an image to an independent recording medium. The present invention can be implemented by preparing independent images for C, M, and Y on the image memory.

In addition, in Example 1, images are formed using separate colors for each separated image, but by replacing all toner in the image forming section with black, for example,
It becomes possible to perform color separation using the same color as is done in printing.

Furthermore, the present invention is applicable not only to image forming apparatuses using an electrophotographic process but also to other recording apparatuses, such as inkjet recording apparatuses.

Further, the present invention is particularly effective in a recording apparatus that carries a color image while conveying a recording material with a belt.

[Effects of the Invention] As explained above, by performing the output operation in order from the side closest to the recording medium ejection part, it is possible to transport the recording medium in advance, and the operation time is shortened. There is.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a color copying apparatus embodying the present invention, FIG. 2 is a circuit diagram of an image processing section of the color copying machine embodying the present invention, and FIG. 3 is a diagram showing image forming operation. . 10] is a reader section, 102 is a printer section, 301 is a polygon scanner, 302, 303, 304, 305 is an image forming section, 306 is a rotating belt, 307 is a fixing device, 308 is a paper feed section, 309.310 is a cassette, 311 is an adsorption charger, 312 is a transfer belt roller, 313 is a developing device, 31
4 is a sleeve, 315 is a primary charger, 316 is an auxiliary charger, 317 is a cleaner, 318 is a photosensitive drum, 319 is a transfer charger, 322, 323, 324 is a neutralization charger, 3
25 is a peeling charger, 326.327 is a pre-fixing charger, 3
28 is a belt cleaner, 329 is a paper leading edge sensor, 201
202 is a line sensor, 202 is an A/D converter, 203 is a shading correction circuit, 204 is an image memory, 205
C. 205M, 205Y, 205 have LOG conversion circuit,
206C. 206M, 206Y, 206 are masking/UCR circuits, 207C, 207M, 207Y, 207 are γ
Correction circuit, 208C. 208M, 208Y, and 208 are laser drivers.

Claims (2)

[Claims] (1) An apparatus comprising a plurality of image forming means arranged in order from a discharge section from which a recording medium on which an image has been formed is discharged, each image forming means forming an image on an independent recording medium, An image forming apparatus comprising means for controlling the recording medium to be ejected in order from the recording medium on which an image has been formed by the image forming means closest to the ejecting section. (2) When the sum of the length of the recording medium and the interval between the recording media is longer than the distance between the image forming means, image formation is performed in order from the image forming means closest to the discharge port of the recording medium. An image forming apparatus according to claim (1).