JPS59206843A - Electrostatic recording device - Google Patents

Abstract

PURPOSE:To change the gradation of a reproduced picture by providing the titled device with a selecting means for selecting the gradation of a reproducing/ recording system proper to picture recording indicating the density of a reproduced/recorded picture or the gradation of a reproducing/recording system proper to the picture recording of continuous gradation. CONSTITUTION:A charging variable control device E1 controlling bias voltage to be applied to a grid 4a of a charging device 4 by a control part and a light control device E2 controlling the quantity of light emission of an electric light lamp 5 execute proper control on the basis of information indicating whether a picture of an original on an original platen 1 is a linear picture or a gradation picture or the picture information of an original inputted from a detector 3 such as a photocoupler to a control part so that the devices E1, E2 provide a charging variable and an exposure variable applying a gamma value proper to the linear picture or gradation picture. In addition, the control part controls also a development bias control device E3 controlling bias voltage to be applied to a developing sleeve 7a of a developing device 7 so that development with proper density is attained without fog.

Description

[Detailed Description of the Invention] [Industrial Application] The present invention relates to an electrophotographic photoreceptor (hereinafter simply referred to as a photoreceptor).
) is uniformly charged by a charging device, the charged surface is exposed to light by an exposure device to form an electrostatic latent image, and the electrostatic latent image is developed into a toner image by a developing device. It relates to a recording device that transfers and fixes onto recording paper.

[Prior art]

Conventionally, electrostatic recording devices such as those described above have been provided with means to control and adjust the conditions of each process such as charging, exposure, and development. It was established for the purpose of adjusting the concentration in.

On the other hand, in electrophotographic methods, it is also known to change the gradation of reproduced images, that is, the γ value, but changing the gradation requires delicate adjustment of the conditions of each process. was.

Therefore, although it was possible to create a machine with a specific gradation, it was considered difficult to freely change the gradation using a single machine.

[Purpose of the invention]

An object of the present invention is to provide an electrostatic recording device that can change the gradation of a reproduced image.

[Structure of the invention]

The present invention is an electrostatic recording device that includes at least each process means of charging, exposure, and development, and is suitable for recording images in which the density of reproduced recorded images is high or low (including zero density). An electrostatic recording apparatus characterized by having a selection means for selecting a γ value of a reproduction recording system suitable for performing continuous tone image recording.

In the present invention, the selection of the γ value of the reproduction recording system suitable for recording an image with high or low density of the reproduction recorded image and the γ value of the reproduction recording system suitable for recording a continuous tone image is carried out. ,
This can be done by selecting a combination of the charged potential on the surface of the photoreceptor and the amount of exposure.

As a means of changing the uniform charging potential on the surface of the photoreceptor, there are methods such as changing the voltage applied to the corona discharge electrode of the charging device, changing the bias voltage of a control electrode such as a grid electrode, and uniformly exposing the surface of the photoreceptor after charging. Conventionally known methods can be used, such as a method of uniformly lowering the potential using a photoreceptor, and a method of changing the speed of the photoreceptor.

In addition, as means for changing the exposure amount, there are conventionally known methods such as changing the light amount of the original illumination lamp, installing a neutral density filter or diaphragm in the exposure optical system, and further changing the scanning speed in the case of slit exposure. method is used.

If the method of changing the speed is used to change either the charging potential or the exposure amount, the other method should be used to change the other one because of the relationship between the charging potential and the exposure amount. This is preferable because combinations of related variation amounts can be freely set. However, when changing the charging potential and exposure amount depending on the type of image to be recorded, the charging potential and exposure amount must be changed to either increase or decrease both, as explained below. Even if the change is made by switching the speed, it is possible to record more clearly and reproducibly than in conventional electrostatic recording devices.

Next, how to change the charging potential and exposure amount using the above-mentioned charging potential changing means and exposure amount changing means will be explained with reference to FIGS. 1 and 2. do.

FIG. 1 is a graph showing the relationship between the surface potential of the photoreceptor and the development density when an organic photoreceptor is used as the photoreceptor and a conductive magnetic toner is used as the developer, and FIG. 2 is a sensitometry graph.

In an electrostatic recording device that can obtain the relationship between the photoreceptor surface potential and the developed density as shown in Figure 1, the charged potential of the photoreceptor is raised to about 500 V at a negative potential that satisfies the developed density. Increase the voltage to about 400V for the black part of the original.
, when exposed with an exposure amount such that the white part becomes about 50V,
The electrostatic latent image obtained is developed under the same developing conditions as those shown in FIG. 1, and the relationship between the density of the copy image transferred and fixed onto the recording paper and the image density of the original is expressed by curve A in FIG. 2. On the other hand, the charging potential of the same photoreceptor is lowered to about 300V, which is just beyond the saturation stage, and the exposure is made so that the black part of the original is about 250V and the white part is about 50V. If you expose with a lower amount, you will be able to develop and develop under the same conditions.
The relationship between the transferred copy image density and the original image density is the second
It will look like the 8th curve in the figure.

Sensitometric) IJ-curve A has a sensitometric γ greater than 1, which makes the copy image density approximately 1.0 compared to the original image density 0.7, and moreover, the original image density is 0.3.
This is a condition suitable for recording characters, halftone photographs, etc., where the copy image density is 0.1 or less. Sensitometric curve B is a record of a silver halide photograph or the like with a sensitometric γ of approximately 1.0, where the copy image density (5) changes in proportion to the original image density up to at least 1.1. The conditions are suitable for

That is, in the electrostatic recording device shown in the example, when the type of image to be recorded is a text or halftone photograph, the conditions are switched to high charging potential and high exposure amount, and when the type of image to be recorded is a silver halide photograph. In such a case, it is sufficient to switch to the conditions of low charging potential and low exposure amount.

Note that if the photoconductor or development conditions are different, please check the sensitivity accordingly.) Determine the charging potential and exposure amount conditions to obtain IJ-curves A and B, and adjust the charging potential and exposure amount appropriately according to the type of image to be recorded. Of course, it is only necessary to switch to a combination of the potential and the exposure amount.

〔Effect of the invention〕

As described above, the electrostatic recording device of the present invention can switch the charging potential and exposure amount conditions to provide an appropriate sensitometric curve depending on the type of image to be recorded, so that faithful reproduction recording can be achieved. It gives an excellent effect of being able to do the following.

(6)

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between photoreceptor surface potential and development density, and FIG. 2 is a sensitometric graph. A... Sensitome with high charging potential and high exposure amount) IJ-
Curve, B: Sensitometric curve with low charging potential and low exposure amount. Patent applicant: Roku Konishi Photo Industry Co., Ltd. Rosie A. 1. z Procedural Amendment Date: Y/2/1980 Kazuo Wakaaki, Commissioner of the Japan Patent Office 1, Indication of the case, 1983 Patent Application No. 60905 3, Relationship with the person making the amendments Patent applicant's lifespan Tokyo 1-26-2 Nishi-Shinjuku, Shinjuku-ku Name (Name) (127) Konishiroku Photo Industry Co., Ltd. 6 Number of inventions increased by the amendment None 7 Figure 2 of the drawing subject to the amendment 8 Contents of the amendment n 'u-Kanka g4JM! ! Procedural amendment June 2, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Indication of the case 1988 Patent Application No. 60905 2 Invention 0 Title Electrostatic recording device 3 Person making the amendment Relationship to the case Patent Applicant (JE”FS 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name) (127) Konishiroku Photo Industry Co., Ltd. Kanesha 4,
Agent 160 Telephone number 556-60906, Number of inventions increased by amendment 0 7, Claims of the specification subject to amendment, Detailed description of the invention, Column for brief description of drawings and Drawing 8, Amendment Attached sheet of contents (attached sheet) 1. The scope of the percentage claim is corrected as follows. [River] An electrostatic recording device that includes at least each process means of charging, exposure, and development, and is suitable for recording images with high or low density (including zero density) of the reproduced recorded image. An electrostatic recording apparatus characterized by having a selection means for selecting a γ value of a recording system and a γ value of a reproducing/recording system suitable for performing continuous tone image recording. 2. Insert the following between lines 14 and 15 on page 6 of the specification. (1) [[Example] Further, a specific example of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 shows a control system block of the recording apparatus of the present invention, which controls the γ value (the slope of the curve of the recorded image density with respect to the image density of the original) by changing the charging potential of the photoreceptor and the exposure conditions as described above. Figure 4 is a diagram showing sensitometric curves obtained using the recording device shown in Figure 3 by selecting charging conditions and exposure conditions suitable for a line drawing original such as text and two types of gradation drawing originals, respectively. It is a graph showing an example. The recording device shown in FIG. 3 is configured to collect information such as information such as a photocoupler, information on whether the image of the document 2 on the document table 1 is a line drawing or a gradation image, which is input from the operation section to the control section by the operator operating the operation section. Based on the image information of the document 2 input from the detector 3 to the control unit, the control unit controls the charge amount control device E1 that controls the bias voltage applied to the grid 4a of the charging device 4 and the amount of light emitted by the exposure lamp 50. The light amount control device F2IQ \ is appropriately controlled so that the devices E1 and B2 provide a charge amount and an exposure amount to obtain an appropriate γ value for line drawing or gradation drawing. Furthermore, the control section also controls a developing bias control device E3 that controls the bias voltage applied to the developing sleeve 7a of the developing device 7, so that development is performed at an appropriate density without fogging. Reference numeral 6 denotes a light transmitting member that projects light reflected from the original 2 by the exposure lamp 5 onto the surface of the photosensitive drum 8. Al+Bl+B2 in FIG. 4 is the photosensitive drum 8.
has an organic photoreceptor layer for negative charging on its surface, and the charge amount control device E1 switches the potential of the grid 4a of the scorotron charging device 4 with a total current of 500 μA to three levels, as shown in the charging potentials in Table 1. The photoreceptor drum 8 is charged, and the light amount control device E2 switches the amount of light emitted from the exposure lamp 5 into three stages to perform exposure as shown in the exposure amounts in Table 1, thereby achieving the black potential and white potential in Table 1. An electrostatic latent image is formed as shown in
Forming resistance value is 10 from 0 parts and 40 parts of polyester resin.
The developing device 7 uses a one-component developer made of magnetic toner of Ωcm, the gap between the photoreceptor drum 8 and the developing sleeve 7a is 0.3 m, and the surface speed of the developing sleeve 7a when rotating counterclockwise is equal to the surface speed of the photoreceptor drum 8. Approximately 1.1x, developing sleeve 7
The clockwise rotation speed of the magnet body in a is 1000 rpm. Sensitometric curve developed under the conditions that the gap between the layer thickness regulating blade that forms the developer layer on the developing sleeve 7a and the developing sleeve 7a is 0.4 mm, and a constant bias voltage of -30 V is applied to the developing sleeve 7a. It shows. Table 1 A1 and B for clear line drawings and tone drawings, respectively.
By selecting condition No. 2 and selecting condition B1 for intermediate gradation images, it was possible to obtain image recordings with excellent reproducibility of the original images. 3. In the 3rd and 4th lines of page 7, "It is a graph." This is a graph showing an example of a sensitometric curve selected in . 4. On page 7, line 8, "line." is corrected to "E line." 5. Add the following on page 7, line 8: [2... Original, 3... Detector, 4... Charging device,
4a... Grid, 5... Exposure lamp, 7... Developing device, 7a... Developing sleeve, El... Charge amount control device, B2... Light amount control device, B3... Developing bias Control device, A, + + B1 + B2...sensitometric curve. ”6. Add attached figures 3 and 4 to the drawings. Above (5) Figure 3

Claims (1)

[Claims] An electrostatic recording device that includes at least each process means of charging, exposure, and development, and is suitable for recording images with high or low density (including zero density) of reproduced recorded images. 1. An electrostatic recording apparatus comprising a selection means for selecting a γ value of a reproduction/recording system suitable for performing continuous tone image recording.