JPS5946655A - Color image recording method and recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color image recording method and a recording device, and more particularly to a color image recording method and a recording device that form and record a color image using an electrostatic recording method. .

An electrophotographic method is a typical method for forming color images using a so-called electrostatic method.

Conventionally, in order to obtain a color image using this electrophotographic method, the color image is processed using a color separation filter, a charge latent image is created with a light image corresponding to the image forming color, and this is developed using colored toner. A method of repeating four colors is known.

Also, instead of recording the original image directly optically, it is also possible to modulate the light using electrical signals and record it.In any case, toner images of 3 to 4 colors can be recorded. In order to obtain an image, it is necessary to repeat the same image forming process 3 to 4 times.

That is, for example, in the case of a three primary color image (toner image related to Y, M, and C colors described later), it is necessary to use three drums (related to the recording medium) or rotate one drum three times. , in the case of a four-primary color image (toner image related to Y, M, C, and B colors described later), a color image was obtained by using four drums or by rotating one drum four times.

Therefore, in such a method, the apparatus is complicated, large and expensive, or the image formation time is long, resulting in a decrease in recording speed.

The present invention eliminates the drawbacks of such conventional techniques, can be implemented with an extremely compact device configuration, and
A color image recording method that can shorten the image formation time and also obtain a high-quality color image of the same quality as the conventional method that is repeated for each color toner image, and a color image recording method that can be directly used for its implementation. Its purpose is to provide a recording device that can

The configuration of the color image recording method according to the present invention is such that a color image is formed by developing an electrical latent image with a colored toner, and successively transferring and superimposing the image onto a transfer body, in which a black toner image and a color image are formed. The one-color chromatic toner images are formed on the same recording medium and then transferred to the transfer body at the same time.

Further, the configuration of the color image recording device according to the present invention is such that a color image is formed by developing an electrical latent image with a colored toner, and sequentially transferring and superimposing the electrical latent image onto a transfer body. At least one developing device is provided for each of the black toner image and the other chromatic toner image.

The details are as follows.

According to the present invention, black (including gray related to the amount of black toner) and one other color are stored in one drum related to the recording medium in one rotation (for the remaining colors, one drum is allocated for each color). In the 1-drum method, black and one other color are rotated once (for the remaining colors, each color is allocated one revolution).
A color image is recorded by image formation.

That is, for example, a black toner image is formed to reproduce black images, including full-color images, but conventionally,
The drum was rotated once just for this purpose.

In contrast, in the present invention, the black color process is streamlined, and the formation of a black toner image is performed at the same time as the formation of another chromatic toner image. What's more, it does not simply create and transfer two toner images on one drum, but it also streamlines the black process in the multi-step process of recording a so-called full-color image, reducing the overall process time. This makes it possible to shorten the time and downsize the device.

Next, each embodiment according to the present invention will be described with reference to each figure.

First, FIG. 1 is a schematic configuration diagram of a color image recording apparatus according to an embodiment, which is used to implement a color image recording method according to a first embodiment of the present invention.

In the figure, 1 is a recording paper related to the transfer body, 2 is a pickup roll, 3 and 4 are conveyance rolls, 5 and 36 are conveyance belts, and 6, 17, and 25 are first and second belts related to the recording medium. , a third photoconductive drum; 7, 18, 26 a charger; 8 a polygon mirror; 9 an imaging lens; 10, 19;
, 27, 29 are laser beam lights, 11, 20, 28, 3
0 is Y color, N color, B color, C color developer, 12, 21, 3
1 is a transfer device (corona); 13, 22, and 31 are separators related to the corona generator; 14, 23, and 33 are erasers; 15
, 24 and 34 are blades, 16 is a receiving box, and 35 is a fixing device.

Thus, the B and C color developers 28 and 30 are arranged on the third photoconductive drum 25.

Further, in the figure, the recording paper 1 is shown by a dashed line, the conveyor belt 5 is shown by a solid line, and the same belt 36 is shown by a broken line. It is designed to be carried by holding the ends together.

Next, a color image recording method according to a first embodiment of the present invention will be described, including the operation of the apparatus having the above structure.

Therefore, in this embodiment, three photoconductive drums are used to create four-color toner (colored powder) images to form a full-color image.

These four colors are magenta (M color), cyan (C color), and yellow (Y color), which are three developing colors of so-called subtractive color mixture, and black (B color) for improving black reproduction.

First, toner images of each color are created as follows.

For convenience of explanation, the order of each color is Y, M, C.
It is assumed that B is combined with any of Y, M, and C, but the order of each color is not necessarily limited to this order as a definitive one, and this example Here, the other chromatic color is C color.

That is, images of each color are created by the first, second, and third photoconductive drums 6, 17, and 25, and the toner images formed on these photoconductive drums are transferred to the recording paper 1 in a superimposed manner one after another. to obtain a full-color image.

The recording paper 1 related to the transfer body is fed out one by one by a pickup roll 2, transported by conveyance rollers 3 and 4, and the ends of the recording paper 1 are pinched by conveyance belts 5 and 36.
It is conveyed in synchronization with the first, second, and third photoconductive drums 6, 17, and 25.

Then, when the recording paper 1 comes into contact with each photoconductive drum, a transfer device (corona) is used to transfer the toner image onto the recording paper 1.
12, 21, and 31, electrical transfer is performed.

After this transfer, a separator 1, which is an AC corona generator, is used to easily separate the recording paper 1 from each photoconductive drum.
3, 22, and 32 erase the corona charge applied to the recording paper 1 during transfer.

In this way, toner images of each color are transferred onto the recording paper 1 in an aligned state, and the toner images are finally heated and fixed by the fixing device 35 associated with the fixing roller. It is something.

Note that the laser beams 10, 19, 27, and 29 are scanned by one polygon mirror 8 and an imaging lens 9.

Next, a method for forming toner images of each color on a photoconductive drum will be described in detail.

First, a first Y color image is uniformly charged by a charger 7 as the first photoconductive drum 6 rotates, and then an optical image is formed by scanning a laser beam 10 modulated by a signal to be recorded. It irradiates a charge latent image to create an electrical latent image.

Then, Y color toner is attached to this charge latent image by a Y color developing device 11 to form a Y color toner image on the first photoconductive drum 6.

Next, as described above, this is transferred onto the recording paper 1. When the first photoconductive drum 6 is optically scanned to create a latent image, the position of the recording paper 1 is detected, and at the time of transfer, The modulation timing of the laser beam 10 is determined so that the toner image is transferred to a desired position (not shown).

In order to remove the toner remaining on the first photoconductive drum 6 after being transferred onto the recording paper 1 as described above, the eraser 14, which is an AC corona generator, is used to remove the toner on the first photoconductive drum 6 and the toner remaining on the first photoconductive drum 6. The toner is scraped off by the blade 15 after neutralizing the charge and weakening the toner's adhesion to the first photoconductive drum 7, and the scraped toner is collected in a receiving box 16.

Therefore, instead of the above eraser 14, a lamp may be used to remove only the charge remaining on the first photoconductive drum 6 with light, or an eraser and a lamp may be used in combination. It is something.

In this way, a Y color image is obtained, and in the same way, a second M color image is obtained by the second photoconductive drum 17.

Next, toner images relating to the third B color image and the fourth C color image are sequentially formed on the same third photoconductive drum 25.

Here, there is a problem that the B color toner gets mixed into the C color developer, but if you remove the B color toner (mixed toner) from the C color developer, the toner image will be cleaner if the B color comes first. It is something.

That is, as the third photoconductive drum 25 rotates, it is uniformly charged by the charger 26, and then a charge latent image corresponding to the B color is created by the laser beam 27, and this is developed by the B color developer 28. do.

Subsequently, a charge latent image corresponding to the C color is formed by the laser beam 29, and this is developed by the C color developer 30.

The two-color toner images created in this manner are simultaneously transferred onto the recording paper 1, and the following steps are the same as in the case of the Y and M color images described above.

Therefore, when forming two-color toner images on the third photoconductive drum 25, in the above example, the B-color image and the C-color image are made so that they do not overlap with each other.

That is, for example, a B color image is reversely developed so that the B color toner adheres to the area irradiated with the laser beam 27.

There is still a uniform charge remaining in areas other than the developed B color toner image, and if the laser beam 29 is then applied and the exposed area is reversely developed with C color toner, the C color will be created. A toner image can be obtained.

Although the C color toner image may overlap the B color toner image to some extent, this is a color mixture with the B color and does not pose a problem.

In this way, the B and C color toners have the same charge polarity and can be simultaneously transferred onto the recording paper 1 by the action of the transfer device 31.

Note that when the polarities of the two-color toner images formed on the third photoconductive drum 25 are different from those of the toner images on the first and second photoconductive drums 6 and 15, the polarities are set to be the same.
A corona charge is applied before transfer (the application configuration is not shown).

According to this embodiment described above, the black B color toner image and the cyan C color toner image related to the other chromatic color toner image are stored on the third photoconductive drum 25 which is the same recording medium. , and then simultaneously transferred to the recording paper 1, which is a transfer member, so that four-color toner images can be created using three photoconductive drums, and this allows the recording device to be compact. , it is possible to reduce the price and also to shorten the printing time.

Therefore, in this embodiment, the B color of black or the color related to gray does not overlap with the C color of cyan. Therefore, the signal for modulating the laser beam light 27 for B color or gray corresponds to the location where B color or gray is to be reproduced with Y, M, and C colors;
It is best to subtract the color accordingly.

That is, the signal that modulates the laser beam 27 corresponding to black is generated by electrical signals corresponding to Y, M, and C colors. Therefore, if the colors related to Y, M, and C are left as they are, black will be created twice. For this purpose, Y, M
, C, and when a black signal is generated, the signals related to Y, M, and C are subtracted by that amount, so that black is not generated twice.

In addition to the method of obtaining the two-color toner image on the third photoconductive drum 25 in the above embodiment, the following methods are also available.

That is, first, as a method for forming a latent image corresponding to C color, after forming the B color toner image in the above embodiment, a regular process is carried out so that the C color toner image is deposited on the area that was not hit by the laser beam light 27. There is a method for developing it.

In addition, as shown in the latent image formation explanatory diagram of FIG. 2, B, C2
To form a color image, the potential V_0 of the third photoconductive drum 25 is divided into two, V_0_1 and V_0_2, and the laser beam 27 forms a latent image as shown by the solid line in the figure, and the laser beam 29 forms a latent image as shown by the dotted line. An image is created, and each image is normally developed by the B color developer 28 and then by the C color developer 3.
There is a method of reversal development using 0.

In the case of this latter method, the B color and C color developing units 2
A bias voltage approximately equal to the potential V_0_2 is applied to the potentials 8 and 30 to prevent the B color or C print toner image from adhering to unnecessary areas.

In the case of these two methods described above, the third photoconductive drum 2
Since the polarity of the toner image formed on recording paper 1 is different,
Before transferring the toner to the first
It is necessary to apply a corona charge (the application configuration is not shown) so that the polarity is the same as that of the toner image formed on the second photoconductive drums 6 and 17.

In any case, the same effects as those of the first embodiment can be expected with the recording methods according to these two embodiments.

Next, a second embodiment of the present invention will be described, and this embodiment relates to a recording method using one photoconductive drum and two laser beams.

Here, FIG. 3 is a schematic configuration diagram of a color image recording apparatus according to another embodiment, which is used for implementing the color image recording method according to the second embodiment of the present invention.

In the figure, the same numbers as in Figure 1 indicate equivalent parts, and 6A
is a photoconductive drum, 37 is a transfer drum, 38 is a charger,
39 and 43 are laser beam lights, 40 is a polygon mirror,
41 is an imaging lens, 42, 44, 45, 46 are B color, C
47 is a transfer device, 48 is an eraser lamp, 49 is a cleaner, and 50 is a heat roll.

Therefore, also in this embodiment, at least the B and C color developing devices 42 and 44 are on the same photoconductive drum 6A.
It was placed in

Further, this embodiment also relates to a case where the other chromatic color is C color.

That is, with the above configuration, the recording paper ■ is first fed out one by one by the pickup roll 2, and then transferred to the transfer drum 37.
Wrap the end around and secure it.

On the other hand, the photoconductive drum 6A is uniformly charged with a charger 38,
Next, a laser beam 39 is used to irradiate a light image corresponding to the Y color signal to be recorded to create a charge latent image, which is then used by a Y color developer 45 to form a Y color toner image.

At this time, the B, C, and M color developers 42, 44, and 46 are not operated.

The Y color toner image formed as described above is transferred onto the recording paper 1 under the action of the transfer device 47.

Next, a charge latent image corresponding to the M color signal to be recorded is formed by the laser beam 39, and this is developed by the M color developer 46.

At this time, the Y, C, and B color developers 45, 44, and 42 are not operated.

The M color toner image developed and formed as described above is transferred to the recording paper 1.
Under the action of the transfer device 47, the Y color toner image is aligned and transferred to the previous Y color toner image.

These images can be aligned by matching the position of the recording paper 1 and the recording start timing of the laser beam 39.

Next, the B color toner image and the C color toner image are transferred to the first
As in the case of the embodiment, the laser beams 39 and 43 and the B color and C color developers 42 and 44 are used to form the photoconductive drum 6A, which is the same photoconductive drum, and advance it onto the recording paper 1. The B color and C color images are transferred simultaneously by aligning with the Y and M color images created in the previous step.

The four-color toner images thus transferred onto the recording paper 1 are finally fused and fixed by the heat roll 50.

However, in the image forming process according to this embodiment, even after the toner image formed on the photoconductive drum 6A is transferred to the recording paper 1, the charge and toner remaining on the photoconductive drum 6A are erased by the eraser. It is removed by a lamp 48 and a cleaner 49 in preparation for the next image formation, and the laser beams 39 and 43 are scanned by a single polygon mirror 40 and an imaging lens 41.

As described above, according to the present embodiment, the black B color toner image and the cyan C color toner image related to the other chromatic color toner image are on the same recording medium. After forming on the photoconductive drum 6A, the recording paper 1 which is a transfer body is
A full-color image can be obtained by superimposing four-color toner images on a single recording medium photoconductive drum 6A in three rotations. Compared to the recording apparatus according to the embodiment, the apparatus can be further miniaturized and a full-color image can be formed in a short time.

Next, a third embodiment of the present invention will be described.

Here, FIG. 4 is a schematic configuration diagram of a photoconductive drum-related portion in a color image recording apparatus according to another embodiment, which is used to implement a color image recording method according to a third embodiment of the present invention. FIG. 5 is an explanatory diagram of the latent image formation.

In the figure, 51 is a photoconductive drum, 52 is a charger, 53 is a laser beam, 54 is a developing device, and 55 is a transfer device, and the developing device 54 may be configured to be divided into two developing devices. However, in the illustrated example, there is one developing device 54 for B and C colors, which is disposed on the photoconductive drum 51.

In the case of the first embodiment (Fig. 1) mentioned earlier,
In the case of the second embodiment (FIG. 3), in one rotation with respect to the photoconductive drum 25 using the laser beams 27, 29,
Black and one other color are created in one rotation using laser beams 39 and 43, and these use two laser beams 27 and 29 and 39 and 43, respectively.
This is not necessarily necessary, and with the configuration shown in FIG. 4, two-color toner images can be created using one laser beam 53 and one developing device 54 or two developing devices. can be formed.

That is, the photoconductive drum 51 is uniformly charged by the charger 52, and then the photoconductive drum 51 is charged by the laser beam 53 using two signals corresponding to B and C color images, as shown in FIG. The potential V_0, which is the charging potential of
A charge latent image is formed with a potential divided into two halves by approximately V_0/2, and B color toner is adhered to one side and C color toner is adhered to the other side.

When developing these two colors, as shown in the figure, positively and negatively charged toners can be mixed in one developing device 54 for one-bath development, or two developing devices can be used. It may be used and developed in two steps.

In either case, it is necessary to apply a bias voltage approximately equal to the potential corresponding to the center value of the two charge latent images to the developing device, and to make adjustments so that the toner adheres only to the intended location.

In this way, in the case of the first embodiment shown in FIG.
Four color toner images are created by three laser beams and one rotation each of three photoconductive drums, and in the case of the second embodiment shown in FIG.
It is possible to form toner images of four colors using one photoconductive drum, one laser beam, and three rotations, and the recording apparatus is becoming increasingly popular, including the simplification of the recording apparatus shown in Figures 1 and 3. This makes it possible to reduce the size of the printer and to increase the printing speed.

Next, a fourth embodiment of the present invention will be further described.

Here, FIG. 6 schematically shows the structure of a photoconductive drum-related portion in a color image recording apparatus according to yet another embodiment, which is used to implement the color image recording method according to the fourth embodiment of the present invention. 4, the same reference numerals as in FIG. 4 indicate equivalent parts, 56 and 60 are developing devices, 57 is a lamp, 58 is a charger, and 59 is a laser beam.

However, in this embodiment, the B and C color developing units 6
0 and 56 are arranged on the photoconductive drum 51.

In the first to third embodiments described so far,
As an example, it is assumed that the color B of black and the color C of cyan related to one other chromatic color do not overlap.

However, in order to reproduce intermediate colors with low brightness, it is necessary to add one or three of the other M, C, and Y colors to the B color of black.
There are cases where it is better for two colors to overlap, and this embodiment relates to this.

Here, the above case will be explained using an example in which the color B of black and the color C of cyan overlap.

That is, as shown in FIG. 6, after the photoconductive drum 51 is uniformly charged with a charger 52, a laser beam 53,
A C color image is produced by the developer 56, and then the residual charge is transferred to the lamp 5.
After erasing by step 7, it is uniformly charged again by a charger 58, and then charging exposure and development is repeated twice so that a B color image is created by a laser beam, light 59, and developer 60.
It is only necessary to include this step so that the four-color toner images are finally overlapped on the recording paper 1.

As described above, according to this embodiment, one to three of the other chromatic colors overlap with the color B of black, and an intermediate color with low brightness can be reproduced.

In any case, in this embodiment, one photoconductive drum is rotated once for each B color image of black and one color image of other chromatic colors (one photoconductive drum is rotated for each color for the remaining colors). In addition, in the one photoconductive drum method, black and one other color are produced in one rotation (one rotation is allocated to each color for the remaining colors), which simplifies the process.
It also has the feature that the device can be simplified.

In each of the embodiments described above, a laser beam light is used as the light source, but this does not preclude the use of other light sources. It is possible to use a light emitting diode array that is turned on and off by image signals, or a liquid crystal shutter array that is placed between a photoconductive drum and a fluorescent lamp and turned on and off by image signals. .

In addition, although the color order including the light order is constant, as described above, the order of various combinations is also possible.

Therefore, the recording method according to the present invention is particularly effective in the case of a combination of black (B) and any of the other three chromatic colors; In other words, by using two photoconductive drums, one rotation of three colors, or one photoconductive drum, three rotations, black B color and two other chromatic colors can be combined. This does not preclude use when creating an image by combining them.

Furthermore, in each of the examples, the recording apparatus uses a photoconductive drum as the recording medium.
This can be anything other than a drum, such as a sheet-like belt. Furthermore, instead of a photoconductive drum, a general insulator is usually used, and instead of an optical image, an electrostatic recording needle or ion beam is used. The present invention can also be applied to the case where an electrostatic image is formed by controlling the flow.

The basic technical idea related to the present invention is not only related to black and other chromatic colors, but also related to other chromatic colors other than black. This is aimed at streamlining the black process in recording.

As described above, according to the present invention, it is possible to shorten the image forming time, and to provide a color image recording method and a recording device thereof having an extremely compact device configuration, which is excellent in practical use. This can be said to be an invention that can be expected to have a positive effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural diagram of a color image recording apparatus according to an embodiment, which is used for carrying out a color image recording method according to a first embodiment of the present invention, and FIG. 2 is a diagram showing the formation of a latent image. An explanatory diagram, FIG. 3 is a schematic configuration diagram of a color image recording apparatus according to another embodiment, which is used for implementing the color image recording method according to the second embodiment of the present invention, and FIG. FIG. 5 is a schematic configuration diagram of a photoconductive drum-related portion in a color image recording apparatus according to another embodiment, which is used for carrying out the color image recording method according to the third embodiment of the present invention. Image formation explanatory diagram,
FIG. 6 is a schematic configuration diagram of a photoconductive drum-related portion in a color image recording apparatus according to yet another embodiment, which is used to implement a color image recording method according to a fourth embodiment of the present invention. . 1... Recording paper, 6, 17, 25... First, second, third photoconductive drum, 6A, 51... Photoconductive drum, 7,
18, 26, 38, 52, 58... Charger, 10, 1
9, 27, 29, 39, 43, 53, 59... Laser beam light, 11, 45... Y color developer, 12, 21,
31, 47, 55...transfer device, 13, 22, 32...
・Separator, 14, 23, 33... Eraser, 15, 2
4, 34... Blade, 20, 46... M color developer, 28, 42, 60... B color developer, 30, 44, 5
6... C color developing device, 35... Fixing device, 37... Transfer drum, 48... Eraser lamp, 49... Cleaner, 50... Heat roll, 57... Lamp.

Claims (1)

[Claims] 1. A color image is formed by developing an electrical latent image with a colored toner, and successively transferring and superimposing the image onto a transfer member, in which a black toner image and one color of another color are formed. Chromatic toner images are a color image recording method characterized by forming them on the same recording medium and then simultaneously transferring them to a transfer body. 2. In the product described in claim 1, a black toner image and a chromatic toner image of one other color are formed on one recording medium in one rotation, and the remaining chromatic toner image is A color image recording method in which an image is created by allocating one recording medium to each color. 3. In the product described in claim 1, a black toner image and a chromatic toner image of one other color are formed in one rotation using one recording medium, and the remaining chromatic toner image is This is a color image recording method in which an image is created by allocating one revolution of the recording medium to each color. 4. In an apparatus that forms a color image by developing an electrical latent image with colored toner, and successively transferring and superimposing the images onto a transfer member, at least a black toner image and one other color are printed on the same recording medium. A color image recording apparatus is provided with a developing device for each chromatic toner image. 5. A color image recording device according to claim 4, in which the developing devices for each of the black toner image and the chromatic toner image of one other color are a single developing device. .