JPS62131270A - Electrophotographic method - Google Patents

Abstract

PURPOSE:To emphasize the color tone of a specific original and to regenerate the original by adjusting the output distribution of plural lamps having different light source colors to project the original and varying a developing condition in accordance with the output distribution of respective lamps. CONSTITUTION:When fluorescent lamps 11, 12 having different spectral energy distribution respectively project the surface of the original set up on an original platen glass 6, an electrostatic latent image is formed on the surface of a photosensitive drum 1 and developed by a developing device 3 to form a developed image, which is transferred to a transfer material by a transfer charger 4. The lamps 11, 12 have green and pink light source colors respectively, and usually both lamps 11, 12 project the original with the same intensity. To regenerate the vermilion color of a seal impression or the like, the output of the green light source lamp 11 is increased and the frequency of a developing bias is set up to high frequency, and in case of a blue thin line or a solid part photographing, the output of the pink light source lamp 12 is increased and the frequency of a developing bias is reduced.

Description

[Detailed Description of the Invention] [Objective of the Invention] "Industrial Application Field" The present invention relates to an illumination method and a developing method used in an image forming apparatus such as an electrophotographic apparatus or an electrostatic two-scythe apparatus. This paper relates to an electrophotographic method for selecting the optimum value of and consistently obtaining good images for any original.

``Prior Art'' Various lamps are used to illuminate original documents in image forming apparatuses such as electrophotographic and electrostatic recording apparatuses. Commonly used lamps include halogen lamps and fluorescent lamps.

On the other hand, there are a wide variety of manuscript types, including general documents, newspapers, catalogs, and photographs. Copying text, etc. is a matter of course, but machines are also required to reproduce various colors in photographs, reproduce the vermilion color of seals in general documents, reproduce the spine of thin lines on graph paper, and reproduce complementary colors. It will be done.

An example of a conventional electrophotographic apparatus will be described with reference to FIG. 6, which is a side sectional view. The original on the original platen glass 6 is irradiated by the original lamp 8, and the reflected light image passes through the lens array 5 and is irradiated onto the photosensitive drum 1, which rotates in synchronization with the movement of the original platen glass 6 in the direction of the arrow shown in the figure, and is applied to the charger 2. An electrostatic latent image is formed on the photosensitive drum 1 which holds a uniform charge. The electrostatic latent image is made into a visible image by the developing device @3.

The developed image on the photosensitive drum 1 is transferred by a transfer charger 4 onto a transfer material fed from a paper feeding device (not shown), and then sent to a fixing device (not shown) where it is fixed. The residual developer on the photosensitive drum 1 is cleaned by a cleaning device 7.

In order to reproduce each color of the original, an illumination device is formed by combining the types of lamp light sources and the filter 9 shown in FIG. 6. This is used in normal machines. However, there are many different types of people, such as those who most desire red reproduction (particularly for seals) and those who only desire blue reproduction.

One way to fulfill the above wishes is to incorporate several types of filters as shown in Figure 6, and replace the filters as necessary. Also, as shown schematically in FIG.
．． 12 are arranged on both sides of the lens array, each lamp is composed of a lamp with a different light source color, and the intensity of each light is changed as necessary to reproduce the required color.

It is true that each of the above methods is extremely effective for color reproduction.

``Problems to be solved by the invention'' However, the type of manuscript will differ depending on the color you want to reproduce. That is, the red color is often used for seals and other universities, while the blue color is used for single lines on graph paper, so-called solid areas with a large colored area, and the like. Therefore, in the above method, it is time-consuming to change the filter 9 depending on the color tone of the original or the color desired to be reproduced. Although it is easy to operate by changing the intensity of the light from the fluorescent lamps 11 and 12, it is possible to make the desired copy corresponding to the area for which color reproduction is desired. It would be advantageous if a clear image of the image could be emphasized.

The present invention relates to an illumination device that normally reproduces average colors in image forming devices such as electrophotographic devices and electrostatic recording devices for general use, and that can automatically or manually reproduce only special colors. The object of the present invention is to provide a developing device.

[Structure of the invention]

"Means for Solving the Problem" The present invention adjusts the output distribution of each of a plurality of lamps having different light source colors, irradiates the original, scans the original image, and projects the original image onto a photoreceptor. This is an electrophotographic method that includes the steps of forming a latent image by using a plurality of lamps, and then changing the developing conditions of the latent image according to the distribution of the output of each lamp.

"Function" By selectively lighting multiple original lamps with different luminous intensities, the spectral energy distribution of the light that illuminates the original can be changed, and the color tone of a particular original can be emphasized and reproduced. On the other hand, the development conditions, for example, the AC development bias in the case of a jumping development method, are changed to emphasize reproduction of fine lines or reproduction of solid areas.

"Embodiments" Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of an embodiment of the invention. Original table glass 6
Fluorescent lamps 1.12 with different spectral energy distributions are supported so as to reciprocate in the direction of the arrows shown during operation, and are each provided with a reflector plate 14 below which reflects and blocks light.
is arranged to illuminate the original surface on the original platen glass 6, the irradiated light is reflected by the original plate I, the light image passes through the fixed lens array 5, and is directed onto the original platen glass 6.
The image is formed on the surface of a photosensitive drum 1 having a layer of photoconductive photoreceptors that rotates in synchronization with the image. The photosensitive drum 1 is uniformly charged by a charger 2, and an electrostatic latent image is formed on its surface by exposure, and a developing device 3 supplies a developer to turn the electrostatic latent image into a visible image, which is then transferred and charged. In the container 4, the developed image is transferred onto a transfer material fed from a paper feeding device (not shown), and the transfer material is sent to a fixing device (not shown), fixed thereon, and discharged from the device.

After the photosensitive drum 1 has passed the transfer charger 4, residual developer is removed by the cleaning device 7, and the photosensitive drum 1 is exposed to the pre-exposure lamp 1.
3 will be irradiated and his previous history will be erased.

The fluorescent lamp 11 is a lamp whose light source color is green, and has a spectral energy distribution of A in FIG. 2, with the horizontal axis representing the wavelength and the vertical axis representing the specific energy. The fluorescent lamp 12 has a pink light source and has a spectral energy distribution of B in FIG.

Normally, both lamps 11 and 12 illuminate the document with equal intensity. Therefore, the spectral energy distribution is
It becomes the sum of A and B in the figure and is relatively averaged. Therefore, in normal copying, each color is reproduced on an average basis and used for normal purposes. Therefore, there is no need for a filter, and it is sufficient to use two fluorescent lamps, even though one fluorescent lamp would not provide enough light.

Furthermore, compared to halogen lamps, they generate very little heat and do not require any special heat exhaust equipment.

Some writers may want to reproduce the vermilion color of their seals clearly, but not the fine blue lines of graph paper. At that time, the light intensity balance of the fluorescent lamps 11 and 12 is changed by a switching signal from a manual switch by a person. That is, the amount of light from the green light source color lamp of the fluorescent lamp 11 is increased, and the amount of light from the fluorescent lamp 12 is decreased. However, it is assumed that the sum of the amounts of light at this time is the same under normal conditions. In addition, in order to suppress the reproduction of red colors and make the reproduction of blue colors more prominent, the light amount of the fluorescent lamp 11 is decreased and the light amount of the fluorescent lamp 12 is increased. Reference numeral 20 denotes a developing bias power supply that is applied to the developing roller of the developing device.
It is designed to operate in conjunction with the light intensity adjustment in step 2.

In addition, regarding the reproduction of characters such as lines and solid areas during development, taking jumping development as an example, the horizontal axis represents the electrostatic latent image potential on the photosensitive drum 1, and the vertical axis represents the image density, and an image density curve is expressed. This will be explained using Figure 6. If the frequency of the developing bias shown as a parameter is increased, the potential and image density curve, ie, γ, will rise as shown by the dotted line in the figure, for example, and if it is decreased, γ will become clearer, as shown by the solid line in the figure. When γ is high, the reproduction of characters is very good, and on the other hand, when γ is smooth, the reproduction of a wide area colored part, that is, a solid photograph, etc., having various halftones is very good.

That is, when it is desired to reproduce the vermilion color of a seal, etc., the seal is generally used in a general document, and the stamp must be clearly reproduced. Therefore, it is desirable that the lamp output be higher than the output of the green light source lamp A, and that the frequency of the developing bias be high. On the other hand, for blue thin lines or solid area photographs, the output of the pink light source lamp B is increased to reproduce the blue color, and the frequency of the developing bias is set to a low frequency to reproduce the solid area. Furthermore, blue color is generally reproduced using graph paper, etc., and graph paper must be reproduced in order to read the graph, but if the image density is too high, it will be difficult to read the required data. Therefore, reproduction using low frequencies is extremely effective.

Figure 4 shows the lamp output ratio (vertical axis) and developing bias frequency (
(horizontal axis). The lamp output ratio is green light source lamp/pink light source lamp. As the ratio increases, the output of the green light source lamp increases, and at that time, the developing bias is set to the high frequency side manually or in conjunction.

In FIG. 1, example 1 is described in which the light source colors are green and pink, but there are various combinations. For example, a combination of light source colors of white and green, a combination of light source colors of blue and yellow, etc. Further, although the developing method of the embodiment has been explained by taking jumping development as an example, it is not limited to this, and it is also effective in combination with developing methods using various electric field effects.

FIG. 5 shows a side sectional view of another embodiment of the invention. Fifth
In the figure, each electrophotographic device except the illumination device is the same as in FIG. 1, and a description thereof will be omitted.

The illumination device includes fluorescent lamps 15 to 18, each of which is arranged to irradiate the same part of the document on the document platen glass 6 with a selective luminous intensity, and the fluorescent lamp 15 is a blue light source color lamp;
The fluorescent lamp 16 is a green light source color lamp, and the fluorescent lamp 1 is a green light source color lamp.
7 is a yellow light source color lamp, and the fluorescent lamp 18 is a pink light source color lamp. Normally, the amount of light should be equivalent to 1. It becomes possible to freely select the color to be reproduced by changing the light intensity balance of each lamp using signals such as automatic and manual.

〔Effect of the invention〕

The present invention adjusts the output distribution of each of a plurality of lamps having different light source colors, irradiates the document, scans the document image, projects the document image onto a photoreceptor to form a latent image, and then scans the document image. Since the electrophotographic method has a process of varying the developing conditions according to the distribution of the output of each lamp, the image part that is particularly desired to be reproduced is drawn as a line drawing, and a large area of the same color is drawn. It can be emphasized accordingly.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an apparatus used for carrying out the present invention;
Figure 2 is a diagram showing the spectral energy distribution of the lamp in Figure 1, Figure 3 is a diagram showing the image density curve of the developing device in Figure 1, and Figure 4 is the relationship between lamp output ratio and developing bias frequency. FIG. 5 is a side sectional view of another embodiment, and FIG. 6 is a side sectional view of a conventional example. 1. Photosensitive drum 2. Charger 6. Developing device 4
・・Transfer charger 5・・Lens array 6・・Document table glass 7・・Cleaning device 8・・・Document lamp 9
...Filter 11.12...Fluorescent lamp 13...
Pre-exposure lamp 14...Reflector plate 15-18...Fluorescent lamp 20...Development bias power supply A...Green light source lamp B...Pink light source lamp.

Claims (1)

[Claims] 1. Adjust the output distribution of each of a plurality of lamps with different light source colors, irradiate the document, scan the document image, project the document image onto a photoreceptor to form a latent image, and then scan the document image. An electrophotographic method that includes a process in which developing conditions are varied according to the distribution of output from each lamp.