JPH05289547A - Electrophotographic process controller - Google Patents

Abstract

PURPOSE:To restrain the fluctuation of the transfer ratio of a toner image to the minimum and to output a high definition color image by controlling the voltage of a transfer charger based on information on superposed image already transferred of each picture element area on a transfer material. CONSTITUTION:A transfer charger controller 4 calculates optimum voltage for driving the transfer charger according to an input signal from the central arithmetic device of an image forming device and transmits it to a transfer charger driving part. An input/output control device 5 takes charge of an interface with an external device, receives a control signal from the central arithmetic device of the image forming device and a picture element amount signal from an image write part, and transmits data to a driving voltage calculation part 6 in a fixed timing. The calculation part 6 calculates the driving voltage of the transfer charger based on data(picture element amount signal, etc.) from the device 5 and transmits it to the device 5. The device 5 receives the driving voltage of the transfer charger from the calculation part 6 and transmits it to the transfer charger driving part. Therefore, the fluctuation of the transfer ratio of the toner image is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for forming a color image by sequentially forming images of a plurality of colors by an electrophotographic process and transferring the images of the plurality of colors on a transfer material by a transfer charger. The present invention relates to an electrophotographic process control device for an apparatus.

[0002]

2. Description of the Related Art Vol.9, No.4 of the Institute of Static Electricity (1985)
As is known from "Color electrophotography" on pages 253 to 261, imaging technologies such as photographic technology, printing technology, and television have become popular due to colorization, but electrophotographic technology, particularly colorization of PPC, has been slow to spread. .. However, recently, the number of color materials and documents has increased in the office, and the color soft copy by DRT has spread, and the interest and demand for color PPCs and color printers have increased. It is expected that this tendency will become stronger and colorization of electrophotographic technology will progress in the future. Under such circumstances, various colorization technologies are currently being studied. Although the electrophotographic technology is in its maturity in the black and white field, there are still technical problems specific to colorization.

In general, color electrophotographic technology often refers to full-color electrophotographic technology. This full-color electrophotographic technology is based on the color separation information of the three colors of the original,
The original color is reproduced using cyan, magenta, and yellow toners, and black toner may be added to the toner as necessary.

When the color electrophotographic process is compared with the black and white electrophotographic process, one of the peculiar techniques of the color electrophotographic process is a multiple transfer device for superposing and transferring toner images of respective colors on a transfer paper. The condition required for this multiple transfer device is that the transfer paper is conveyed to a fixed position on the photoconductor drum and the toner images of the respective colors are transferred onto this transfer paper in multiple transfer without color misregistration. It is mentioned that the transfer rate of the toner image of the second color does not decrease as compared with the above, and there is no uneven transfer of the toner image or retransfer of the toner image to the photosensitive drum.

A typical multi-transfer apparatus is a corona transfer method in which a toner image is transferred by using a transfer charger, and a bias voltage is applied to a transfer roller (or transfer drum) so that the toner on the photosensitive member is transferred by the transfer roller. There are a bias roller transfer system for transferring an image onto a transfer paper and an intermediate transfer system for transferring a toner image on a photoconductor onto a transfer paper via an intermediate drum.

FIG. 6 is a block diagram showing an example of a general corona transfer system using corona discharge. The transfer charger control unit 1 receives a control signal from a central processing unit of the image forming device (or a device above the transfer device). Here, the image forming apparatus forms a color image by sequentially forming images of a plurality of colors by an electrophotographic process and transferring the images of the plurality of colors on the transfer material by the transfer charger 3. The transfer charger control unit 1 sends a voltage for driving the transfer charger 3 to the transfer charger drive unit 2 when a drive request signal (timing signal) for the transfer charger 3 is sent by a control signal from the image forming device.
A mechanism (power pack or the like) for driving the transfer charger 3 is mounted on the transfer charger driving unit 2, and the transfer charger 3 is driven by the voltage sent from the transfer charger control unit 1. The transfer charger 3 is driven by the transfer charger driving unit 2 to perform corona discharge to the back surface side of the transfer material to transfer the toner image on the photoconductor onto the transfer material.

The bias roller transfer method is basically the same as the corona transfer method except that the transfer charger 3 is replaced by a transfer roller (or transfer drum).

[0008]

In the above-mentioned corona transfer system, the problem (1) is caused by the change in the electrical characteristics of the toner when it is transferred onto the transfer paper. At the time of image transfer, the same transfer rate as the transfer rate of the first color toner image cannot be obtained. Such a change in transfer rate appears only as a change in toner image density in a black and white electrophotographic process, and is therefore considered to have a relatively wide allowable range. However, in a color electrophotographic process, a slight change in toner image density is possible. Also greatly changes the color tone of the color image. This problem also exists in the bias roller transfer method and the intermediate transfer method.

SUMMARY OF THE INVENTION The present invention provides an electrophotographic process control apparatus which can improve the above-mentioned drawbacks, minimize the fluctuation of the toner image transfer rate, and output a high-quality color image. To aim.

[0010]

In order to achieve the above object, a first aspect of the present invention is to sequentially form images of a plurality of colors by an electrophotographic process and superimpose the images of the plurality of colors on a transfer material by a transfer charger. In an electrophotographic process control device of an image forming device for forming a color image by transferring the image by a transfer, the voltage of the transfer charger is controlled based on the transferred superimposed image information for each pixel or each predetermined image area on the transfer material. According to the invention of claim 2, in the electrophotographic process control device of claim 1, the transfer charger control means sets the voltage of the transfer charger to each pixel on the transfer material. Alternatively, the invention is controlled by a fuzzy operation based on the transferred superimposed image information for each predetermined image area. In the electrophotographic process control apparatus according to claim 1, the transfer charger control means uses the transfer charger's optimum voltage based on the transferred superposed image information for each pixel or a predetermined image area on the transfer material. It is calculated by a network and controls the voltage of the transfer charger.

[0011]

According to the first aspect of the present invention, the transfer charger control means controls the voltage of the transfer charger based on the transferred superimposed image information for each pixel on the transfer material or for each predetermined image area. According to the second aspect of the present invention, the transfer charger control means controls the voltage of the transfer charger by fuzzy calculation based on the transferred superimposed image information for each pixel or each predetermined image area on the transfer material.

According to the third aspect of the present invention, the transfer charger control means calculates the optimum voltage of the transfer charger by the neural network based on the transferred superimposed image information for each pixel or each predetermined image area on the transfer material. Then, the voltage of the transfer charger is controlled.

[0013]

FIG. 2 shows a first embodiment of the present invention. This first
The embodiment is an electrophotographic process control device of an image forming apparatus that forms a color image by a color electrophotographic process, for example, a copying machine (or a printer, a facsimile, etc.), and has a transfer charger control device 4. The image forming apparatus described above is configured such that image signals of a plurality of colors obtained by color-separating an original image are sequentially written on the photosensitive drum by an image writing unit while being uniformly charged by a charger while rotating the photosensitive drum by a motor. To form a color latent image by using a developing device to develop the latent electrostatic image with a toner of each color and transfer it onto a transfer paper (or a transfer material such as a transfer drum) by superimposing the color. Get the image. The transfer charger control device 4 controls the transfer device according to the information of the original image in the image forming device to eliminate the fluctuation of the toner image transfer rate and output a high-quality color image. Drive voltage calculation unit 6
Have.

The transfer charger control device 4 is basically replaced with the transfer charger control unit 1 in the conventional transfer device shown in FIG. 6, and is a central processing unit of the image forming device (or a higher order device of this transfer device). The optimum voltage for driving the transfer charger 3 is calculated from the input signal from the device) and is sent to the transfer charger drive unit 2. The input / output management device 5 serves as an interface with an external device, receives a control signal from the central processing unit of the image forming device and a pixel amount signal from the image writing unit, and transmits data to the drive voltage calculation unit 6 at a predetermined timing. send. The drive voltage calculation unit 6 calculates the drive voltage of the transfer charger 3 based on the data (pixel amount signal, etc.) from the input / output management device 5 to calculate the input / output management device 5.
Send to. When the input / output management device 5 receives the drive voltage of the transfer charger 3 from the drive voltage calculation unit 6, the input / output management unit 5 sends it to the transfer charger drive unit 2.

Next, the operation of the first embodiment will be described in detail. The input / output management device 5 serves as an interface with an external device, and receives various signals from a control signal (a phase signal indicating the rotation phase of the photoconductor drum, a clock signal of the entire color electrophotographic process, etc.) from the central processing unit of the image forming device. Timing is generated, and data such as the pixel amount signal received from the image writing unit is sent to the drive voltage calculation unit 6 based on these various timings. The pixel amount signal referred to here is already present in a portion (pixel area or predetermined image area, for example, an area for several lines in the sub-scanning direction) on the transfer paper, which is currently being transferred by a transfer device using a transfer charger. This is a signal indicating the amount of toner attached.

The pixel amount signal is actually obtained by integrating the writing signal (image signal) in the image writing unit for each predetermined transfer area (pixel area or predetermined image area, for example, an area for several lines in the sub-scanning direction). While storing in memory,
This is a signal obtained by sequentially reading the values for the area currently being transferred when transferring the second and subsequent toner images. Therefore, when the toner image of the first color is transferred, the pixel amount signal is 0 for all areas,
Further, when the toner on the transfer paper is not transferred even when the toner image of the second color is transferred, the pixel amount signal becomes 0.

2 to 4 show the concept of the pixel amount signal. Areas and their numbers in the figure are added for the purpose of explanation and have no absolute meaning. As shown in FIG. 2, when the first-color toner image T1 on the photosensitive drum 9 is transferred onto the transfer paper 7, there is no transferred toner on the transfer paper 7, and the pixel amount signal becomes 0 for all areas. .. As shown in FIG. 3, when the toner image T2 of the second color is transferred, the transfer paper 7 reads out the amount of toner transferred when the toner image T1 of the first color is transferred from the memory for each area to form pixels. A quantity signal is generated. In the example shown in FIGS. 2 to 4, the transfer device using the transfer charger 3 tries to transfer to the area of area number 6, but as shown in FIG. 2, a pixel amount signal at the time of transferring the first color toner image T1. Is 0, and the pixel amount signal at the time of transferring the second color toner image T2 is the first color toner image T1 as shown in FIG.
Is 4, which indicates the amount of transferred toner at the time of transfer, and as shown in FIG. 4, the pixel amount signal at the time of transfer of the second color toner image T2 is the transferred toner at the time of transfer of the first color toner image T1. And the amount 2 of the transferred toner at the time of transferring the second color toner image T2.

Further, the drive voltage calculation unit 6 is based on the data (pixel amount signal) sent from the input / output management device 5 so that the transfer rate of the toner image of each color can be minimized. The drive voltage is calculated for each transfer area (pixel area or predetermined image area, for example, an area for several lines in the sub-scanning direction) and sent to the input / output management device 5. One of the simplest implementation methods of the driving voltage calculation unit 6 is an optimum transfer such that the transfer rate of the toner image of each color can be minimized with respect to a typical toner adhesion amount on the transfer paper 7 through experiments or the like. The voltage (driving voltage of the transfer charger 3) is obtained and stored as a table in the ROM or the like, and the driving voltage calculation unit 6 refers to the table and corresponds to the data sent from the input / output management device 5. The drive voltage of the transfer charger 3 is obtained for each transfer area (pixel area or predetermined image area, for example, an area for several lines in the sub-scanning direction) and sent to the input / output management device 5.

When the input / output management unit 5 receives the drive voltage of the transfer charger 3 from the drive voltage calculation unit 6, it receives a control signal from the central processing unit of the image forming device (a phase signal indicating the rotational phase of the photosensitive drum, a color electronic device). The drive voltage of the transfer charger 3 is sent to the transfer charger drive unit 2 based on various timings generated from the clock signal of the entire photographic process). The transfer charger drive unit 2 drives the transfer charger 3 with the voltage sent from the input / output management device 5. The transfer charger 3 is driven by the transfer charger driving unit 2 to perform corona discharge to the back surface side of the transfer paper to transfer the toner image on the photosensitive drum onto the transfer paper 7.

In the first embodiment, the transfer charger 3 which has conventionally been changed only by the environmental conditions, the type of transfer paper, etc.
Drive voltage is dynamically controlled for each transfer area according to the image information (data on the amount of transferred toner on the transfer paper), so fluctuations in the transfer rate of the toner image of each color can be minimized and the density of the color image can be reduced. Fluctuations and color tone fluctuations can be minimized, and high-quality color images can be output.

The second embodiment of the present invention is the same as the first embodiment except that the drive voltage calculation unit 6 includes a fuzzy arithmetic unit and a seal required to drive the fuzzy arithmetic unit.
The one having a mechanism such as a memory of a membership function is used. The basic operation of the second embodiment is the same as that of the first embodiment except for the following points.

The drive voltage calculation section 6 is based on the data (data such as the pixel amount signal) sent from the input / output management device 5 so that the transfer rate of the toner image of each color can be minimized. Driving voltage is obtained for each transfer area (pixel area or predetermined image area, for example, an area for several lines in the sub-scanning direction) by fuzzy calculation and sent to the input / output management device 5. In this drive voltage calculation unit 6, the fuzzy arithmetic unit receives data from the input / output management unit 5 to generate a drive voltage for the transfer charger 3 and to make each input / output parameter fuzzy / non-fuzzy. The memory in which the membership function of (1) is created and stored by experiments or the like is incorporated in advance. In this fuzzy arithmetic unit, not only the pixel amount signal is input from the input / output management unit 5 as in the first embodiment, but also the type of transfer paper, environmental conditions such as temperature and humidity, surface potential of the photosensitive drum, The state of each color toner is parameterized and input from the central processing unit of the image forming apparatus or the like via the input / output management device 5, and the transfer rate of the toner image of each color is minimized based on these data. The drive voltage of the transfer charger 3 is obtained by fuzzy calculation for each transfer area and sent to the input / output management device 5.

In the second embodiment, as in the first embodiment, it is possible to minimize the fluctuations in the transfer rate of the toner image of each color, and to minimize the density fluctuations and color tone fluctuations of the color image. It is possible to output a high-quality color image.

The third embodiment of the present invention is the same as the first embodiment, except that the drive voltage calculation unit 6 having a neural network is used. The basic operation of the third embodiment is the same as that of the first embodiment except for the following points. The driving voltage calculation unit 6 converts the data sent from the input / output management device 5 into parameters that can be input to the neural network (performs normalization processing, etc.) and gives the parameters to the neural network. The neural network has been learned by a predetermined learning method using the optimum drive voltage of the transfer charger 3 obtained by an experiment or the like in advance for each parameter so that the transfer rate of the toner image of each color can be minimized, as a teacher value. Has become
The optimum drive voltage parameter of the transfer charger 3 is output according to each parameter. The drive voltage calculation unit 6 converts the drive voltage parameter of the transfer charger 3 output from the neural network into the drive voltage of the transfer charger 3 and sends it to the input / output management device 5. In this case, as shown in FIG. 5, a neural network having a hierarchical structure in which an input layer 8a, an intermediate layer 8b and an output layer 8c are laminated is used, and the pixel quantity signal is input / output controlled as in the first embodiment. Not only is it input after being converted into parameters by the drive voltage calculation unit 6 through the device 5, but the parameters such as the type of transfer paper, the environmental conditions such as temperature and humidity, the surface potential of the photosensitive drum, the state of each color toner, etc. are parameterized. The data is input from the central processing unit of the image forming device or the like through the input / output management device 5 after being converted into parameters by the drive voltage calculation unit 6, and based on these data, the transfer rate of the toner image of each color is minimized. The drive voltage parameter of the transfer charger 3 that can be suppressed is obtained by fuzzy calculation for each transfer area.

In the third embodiment, as in the first embodiment, fluctuations in the transfer rate of toner images of respective colors can be minimized, and density fluctuations and color tone fluctuations of color images can be minimized. It is possible to output a high-quality color image. Moreover, due to the generalization capability of the neural network, the driving voltage calculation unit 6 can be constructed with fewer experiments. In other words, the voltage calculation function of the drive voltage calculation unit 6 can be realized from a smaller number of combinations for each input data of the neural network, and when the same voltage calculation function is realized by the table reference method, etc. Compared to having to carry out various experiments and to keep a huge amount of tables, it is possible to significantly reduce the development period and cost.

[0026]

As described above, according to the first aspect of the present invention, images of a plurality of colors are sequentially formed by the electrophotographic process, and the images of the plurality of colors are superposed and transferred on the transfer material by the transfer charger. In the electrophotographic process control apparatus of the image forming apparatus for forming a color image, the transfer charger for controlling the voltage of the transfer charger based on the transferred superposed image information for each pixel or each predetermined image area on the transfer material. Since the control means is provided, fluctuations in the transfer rate of the toner images of the respective colors can be minimized, density fluctuations and color tone fluctuations of the color image can be minimized, and a high-quality color image is output. It becomes possible.

According to a second aspect of the present invention, in the electrophotographic process control apparatus according to the first aspect, the transfer charger control means sets the voltage of the transfer charger to each pixel or a predetermined image area on the transfer material. Since it is controlled by fuzzy calculation based on the transferred superimposed image information for each, it is possible to minimize the fluctuation of the transfer rate of the toner image of each color and minimize the density fluctuation and color tone fluctuation of the color image. It is possible to output a high quality color image.

According to a third aspect of the present invention, in the electrophotographic process control apparatus according to the first aspect, the transfer charger control means sets the optimum voltage of the transfer charger to each pixel on the transfer material or to a predetermined value. Since the voltage of the transfer charger is calculated by a neural network based on the transferred superimposed image information for each image area, fluctuations in the transfer rate of the toner image of each color can be minimized, and a color image can be obtained. The density fluctuation and the color tone fluctuation can be minimized, and a high-quality color image can be output. Moreover, due to the generalization ability of the neural network, it can be constructed with less experiments, and the development period and cost can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a transfer charger control device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a pixel amount signal of the embodiment.

FIG. 3 is a diagram for explaining a pixel amount signal of the same embodiment.

FIG. 4 is a diagram for explaining a pixel amount signal of the embodiment.

FIG. 5 is a diagram showing a neural network according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a conventional transfer device.

[Explanation of symbols]

 4 Transfer Charger Control Device 5 Input / Output Management Unit 6 Drive Voltage Calculation Unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H04N 1/29 G 9186-5C

Claims (3)

[Claims] 1. An electrophotographic process of an image forming apparatus for forming a color image by sequentially forming images of a plurality of colors by an electrophotographic process and transferring the images of the plurality of colors on a transfer material by a transfer charger. The control device is provided with a transfer charger control means for controlling the voltage of the transfer charger based on transferred image information of each pixel or a predetermined image area on the transfer material. apparatus. 2. The electrophotographic process control apparatus according to claim 1, wherein the transfer charger control means sets the voltage of the transfer charger based on the transferred superimposed image information for each pixel or a predetermined image area on the transfer material. An electrophotographic process control device characterized in that it is controlled by a fuzzy operation. 3. The electrophotographic process control apparatus according to claim 1, wherein the transfer charger control means sets the optimum voltage of the transfer charger to the transferred superimposed image information for each pixel or each predetermined image area on the transfer material. An electrophotographic process control device characterized in that the voltage of the transfer charger is controlled by calculation by a neural network based on the above.