JPS58116543A - Half-tone recording system - Google Patents

Abstract

PURPOSE:To perform accurate half-tone recording by forming a latent image of dots differing in area on a recording body, and developing the image from toner having larger particle size successively while using toner differing in particle size. CONSTITUTION:An initial charger 2 charges a photoreceptor 1 to form the latent image of dots S1-S3 of different size by laser light which varies in power with gradations from an exposure device 3. The latent image is processed through the two-component magnetic brush development of a toner supplier 4-1 which uses toner T1 of the largest particle size with high density. The toner T1 sticks to the dots S1 best. Then, two-component magnetic brush development is carried out successively by tonr suppliers 4-2 and 4-3 which use toner T2 and toner T3 of small particles size with less density. The toner T3 is hard to stick undeveloped parts of the dots S1 and S2 and the dots S3. The resulting toner visible image is transferred and heat-fixed to recording paper 7 as shown by 6 and 7. Thus, accurate half-tone recording is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention This invention relates to a gradation recording system, and in particular, to forming latent images of different levels on a recording medium such as a photosensitive drum, and attaching toner to this latent image. The present invention relates to a gradation distribution method in which gradation recording is performed by adjusting the gradation.

(2) Prior art and problems A recording device that forms an abrasion on a recording medium such as a photosensitive drum, attaches toner to this latent image to create a visible scratch, and transfers it onto recording paper to record it. When performing gradation recording, conventionally, latent images of different levels are formed on the recording medium.
Gradation recording is performed by changing the amount of toner adhesion depending on the intensity.

For example, in a method of recording silence using an electrophotographic process, 1
When forming a latent image, the intensity of the latent image is made variable by changing the exposure intensity for the latent image format, and toner is attached to this, so that the amount of toner attached changes depending on the latent image intensity (171).
This allows gradation recording to be performed. However, such conventional methods have the disadvantage that the amount of toner deposited may not be in accordance with the gradation due to variations in photoreceptivity or fatigue of the photoreceptor, resulting in changes in gradation.

(8) Purpose of the invention The purpose of this invention is to improve the above drawbacks.
A latent image is formed on the recording medium by dots with different areas depending on the gradation of the image, and toner with a large particle size is attached to the latent image area with a large area, and toner with a large particle size is attached to the latent image area with a small area. It is an object of the present invention to provide a gradation recording method that allows toner to adhere with a small amount of toner. Another object of the present invention is to provide a gradation recording method in which the density of toner with a large particle size is increased, and the density of toner with a small particle size is decreased, and the toner is attached to a latent image. be.

(Structure of the Invention In order to achieve the above object, the gradation recording method of the present invention applies toner to adhere to the latent image on the recording medium on which a latent image with different levels depending on the gradation is formed. In a recording device that develops an image and outputs it, a toner supply means is provided to supply toner of different particle sizes as toner to a latent image having a different area depending on the gradation level, and the toner with a larger particle size is sequentially used. The present invention is characterized in that gradation recording is performed by increasing the recording density of the latent image portion having a large area by developing the a-element.

(5) Embodiments of the Invention Before describing this invention in detail based on embodiments, the principle of the invention will be briefly explained with reference to the first drawing.

In this invention, for example, three types of drums (S, , S, , Ss) of different sizes are formed according to the image gradation level.
In contrast, toners T, , T2, and T with different particle sizes.

Develop. In other words, when forming the latent image of an image, the first
A latent image is formed by a dot S1, which has a large area and is indicated by S in the figure, and a latent image is formed by dots S3 and S3 whose areas become smaller as the gradation level decreases.

When a latent image is formed by dots with different areas depending on the gradation level and then developed with toner, the image is first developed with toner T1, which has the largest particle size, and then with the toner T1, which has the largest particle size. Developed with toner v1, T.

As a result, the toner T with a large particle size is applied to the dot SI.

Toner T1 and T3 are attached to the remaining part of the toner T, and then toner T1 and T3 are attached to the dot St first. The smallest toner T3 adheres to the toner. Then, only the toner T, which has the smallest particle size, adheres to the dot S. Therefore, in the area developed with toner T, which has a large particle size, there is no white background area, so this toner T is used.

Even if an area of If developed with toner T, there is no white area that would exist between each toner particle, so the area to which toner T is attached is the same as toner T,
This relationship is the same between toners T1 and 11.Moreover, toners T, ,T, are also attached to each dot S, ,S, so that As a result, these dots S1, S! , Sl
The latent image formed by the toner T
, ,T! , T3, the density gradation of the image is such that the dot S is the deepest and the dot Ss is the smallest. Sr)s, >Ss will be displayed as 0. At this time, even if the density of toner T1 is high, the density of toner T3 is
If the density is made lighter, this gradation relationship will become even clearer.

Next, an embodiment of the present invention will be described based on FIGS. 2 to 6.

FIG. 2 shows an example of an image recording device implementing the #j4 recording power type of the present invention, FIG. 3 shows an example of a control circuit for forming a latent image on a photoreceptor, and FIG. 4 shows an example of gradation display. FIG. 5 is an example in which the present invention is applied to a dither method, and FIG. 6 is an explanatory diagram of the image gradation obtained by FIG.

In the figure, l is a photoreceptor, 2 is an initial charger, 3 is an exposure device, and 4
is a developing section, 5 is a recording paper, 6 is a transfer device, 7 is a fixing device, 8 is a static eliminator, 9 is a cleaner, 10 is an optical static eliminator, 11 is a laser, 12 is a modulator, I3 is an optical system, 14 is image storage unit,
15 is a gradation analysis section, 16 is a signal generation section, 17 is a t'i signal control system, and 18 is a td synchronization system.

The photoreceptor 1 is a recording medium on which a latent image is formed, and is constructed by forming a Be-Tθ photoresist film on the surface of a cylindrical drum. The initial charger 2 charges the photoreceptor 1 uniformly. For example, an exposure device 3 having a corona discharge electrode forms a latent image on a photoreceptor 1 with dots of different sizes depending on the gradation, as shown in FIG. 3. As shown in FIG. 1, it has a laser emitter 11, and the laser light emitted by this is analog-modulated by a modulator 12 to change the laser power, as will be described later. When scanning over the body, if the laser power is high, many charges are removed and an area with a large area is obtained. Furthermore, when the laser power is low, only a small amount of charge is removed and a latent image with a small area is obtained. By changing the laser power in 3 steps, 8
．． Latent images of dots of three different sizes as shown in ~S3 are obtained. At this time, the image signals to be recorded are first stored in the image storage memo IJ14, for example, each image signal of 166 gradations,
This is further divided into three gradations by the gradation analyzer 15, and in accordance with this, the control signal generator 16 outputs a control number 100, which is transmitted to the modulator 12 via the signal control system, and thus the laser The light is analog-modulated based on the output of the gradation analyzer 15, thus making it possible to form an image of a desired size m.

Note that a portion of the laser output light is feed-punctured from the optical system 13 via the synchronization system 18 to ensure synchronization.

The developing section 4 supplies toner to the latent image formed by the photoconductor 3 on the photoreceptor 1 and develops it into an aJ' inkstone image, and includes three toner supply devices 4-1 to 4-4. 0 and toner supply device 4-1, which performs development three times by -3.
The toner l'1 with the larger particle size is supplied from the toner supply device 4-2 to perform the first development, and the toner +v with the next larger particle size is supplied from the toner supply device 4-2 to perform the second development nl. Toner T3, which has a small particle size, is supplied from the toner supply device 4-3, and the third operation is carried out.

Nao, "t S+ ~ Sm Ka example td 90X 9
0#m(8,), 40x40μ5(sI), 15X15
The particle size of each toner is, for example, 75μrn (T, ), 35μm (T!), lOμa
(T3), and two-component magnetic brush development is performed by these. At this time, the density of the toner T1 is made higher, and the density of the toner T is made lower.

Next, the operation shown in FIG. 2 will be explained.

Now, the photoreceptor 1 is charged by the initial charger 2, and as described above, the exposure device 3 applies dots S, to Ss of different sizes depending on the front and rear gradations of the image to be recorded. A latent image is formed. In this way, dots S, ~S, of different areas are formed, and fCa (IJ) is first subjected to two-component magnetic brush development using toner T with large particle size and high concentration by toner supply device 4-1. .

This toner T easily adheres to the dot S1. Next, lfl performs two-component magnetic brush development using toner T having the second particle size and density using the toner supply device 4-2. This toner T easily adheres to the undamaged portions of the dots S and to the dots S. Finally, the toner supply device 4-3 performs two-component magnetic brush deterioration using toner 'v, which has a low particle size and density.

This toner 'I' easily adheres to the undeveloped portions of the Vi dots S1 and S2 and to the dot S. Through such a procedure, a toner visible image with gradations is formed on the a1 quadrant on the photoreceptor l.

This toner visible image is transferred onto the recording paper 5 by a transfer device, heated and fixed by a fixing device 7, and is thus transferred onto the recording paper 5.
It is possible to obtain an image with gradation on the top.

The photoreceptor 1 is then neutralized by a static eliminator 8, and residual toner is removed by a cleaner 9.
After the entire surface is exposed to light by 0 and the charge is completely eliminated, it is charged again by the initial charger 2, and the above process is repeated. This shows an example of displaying in three gradations, that is, dots s1, dots S!, dots S, and 03. If this is applied to the dither method, various patterns as shown in Fig. 5 can be obtained. As a result, as shown in Figure 6,
It becomes possible to obtain 46 levels of gradation, and extremely natural gradation expression can be obtained.

That is, in FIG. 5, the size of the dot sl is S
, there is only one way to display it. When this size is to be displayed as the size of a dot Sl, it is necessary to use four dots s, and there is only one way to do this.

However, this size is dot S, and this is 3ffA! If the number of dots S is used and the rest are displayed as dots Ss, and some of these dots S can be left open, there are five ways to display them depending on the number of dots S used, as shown in Figure 6. exists. Then, if we use two dots S, and display the others using dots S, we can obtain 9 different displays depending on the number of dots S, used, and if we use dot S, is and display the other dots, If you display it in sm, you can get 13 different displays, dot S,
If you display only 17 different displays, you can get 17 different displays. As a result, it can be seen that 46 different displays can be obtained.

In the above explanation, the size of the dot is referred to as the size of the dot. Although an example has been described in which three types of magnetic toners are selected, it is of course not limited to VC, and the toner may be either an l-component magnetic toner phenomenon method or a two-component phenomenon f phenomenon method.

(6) Effects of the Invention According to the present invention, an a-image formed by dots with different areas formed on a kl+ 6V recording medium of a photoreceptor is sequentially formed using toners having different particle sizes, starting from the toner with the largest particle size. By developing, If is formed by dots with a large area.
Since it is possible to increase the recording density of the inner part and lower the recording density of the latent image part formed by the small dots, it is possible to accurately record the floor g11. Furthermore, by using a toner with a larger particle size and a higher density, more accurate gradation recording can be achieved.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of this invention, Fig. 2 is an example of an image recording device embodying the invention, Fig. 3 is an example of a control circuit for forming a latent f-image on a photoreceptor, and Fig. 4 is a gradation diagram. A display example, FIG. 5 is an example in which the present invention is applied to a dither method, and FIG. 6 is an explanatory diagram of both front gradations obtained by FIG. In the figure, l is a photoreceptor, 2 is an initial charger, 3 is an exposure device, and 4
1 is a current part, 5 is a recording paper, 6 is a transfer device, 7 is a fixing device, 8 is a static eliminator, 9 is a cleaner, 10 is an optical static eliminator, 11 is a laser, 12 is a modulator, 13 is an optical system, 14 is the painting memory section, 1
5 indicates a gradation analysis section, 16 indicates a signal generation section, 17 indicates a signal control system, and 18 indicates a synchronization system.〇Patent applicant Akira Yamatani, Fujitsu Limited representative patent attorney

Claims (2)

[Claims] (1) In a recording device in which toner is attached to the latent image on a recording medium in which a latent image with different levels is formed depending on the gradation, the latent image is developed and outputted, the area is changed depending on the gradation level. A toner supply means is provided for supplying toner of different particle sizes to different latent images, and by sequentially developing the latent images with toner of large particle size, the recording density of the latent image portion having a large area is increased. A gradation recording method characterized by performing gradation recording. (2) The gradation recording method according to claim (1), characterized in that the toner used is a toner with a large particle size having a high density and a toner with a small particle size having a low density. .