JPS6070872A - Multi-color printer - Google Patents

Abstract

PURPOSE:To arrange color balance by changing respectively the print dot diameter of each optical system and combining properly the diameter depending on the kinds of a color mixture. CONSTITUTION:A prism box 26 has two prisms 24, 25 to change a beam diameter (print dot diameter) at scanning, driven by a solenoid 36 and progressed reversely while crossing an optical path in a direction shown in the arrow. When the box 26 is positioned upward, the prism 34 is positioned on an optical path, and when positioned downward, the prism 35 is positioned on the optical path. Thus, the print dot diameter is changed depending whether the prism 34 or the prism 35 is positioned on the optical path.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a multicolor printing device with good light balance of mixed colors.

Prior Art and Problems Figure 1 shows an overview of a conventional multicolor printing device. In the figure, 1 is a photosensitive drum with a photoconductor layer formed on its surface; 2, 3.4
1 is a charger, 5, 6.7 is an optical system, 8, 9, 10 is a developing device, 11 is a transfer section, 12 is a constant light section, 13 is an 11L lamp, and 14 is a cleaning brush.

The operation of this device is as follows.

That is, the photosensitive drum 1 is rotated in the clockwise direction indicated by the arrow, and the surface thereof is processed in the following procedure.

A Vf'i voltage is uniformly applied to the surface of the strip using the device 2, and scanning is performed using the optical system 5 equipped with a laser, polygon/minion, etc., to form a latent image in which printed dots are gathered. Form in position. This a<'41rJ, cC cyan) color is used for development. After that, this latent image is transferred to 6 by the developing machine 8.
Develop into color. Next, after performing a charging process using a fluoroelectron filter, scanning is performed using an optical system 6 to form a latent image at a predetermined position. This latent image is used for development into M (magenta) color. Thereafter, this latent image is developed into M color by a developing device 9.

Next, after a charging process is performed by the charger 4, scanning is performed by the optical system 7 to form a latent image at a predetermined position iα.

This latent image is used for development into Y (yellow) color. Thereafter, the high angle film is developed into a py color using a developing machine 10. Next, these images are transferred onto a sheet of paper 20 at a rolling section 11, and the transferred images are fixed at a fixing section 12. After the transfer has been completed, the surface of the photosensitive drum 10 is neutralized by a static elimination lamp 15, and then cleaned by a cleaning brush 14.
This completes one cycle of operation.

By the way, in a color electrophotographic apparatus that performs development multiple times, a non-contact type developing machine is required to prevent the developed toner from getting mixed into the developing machine for other colors. It was difficult to achieve a good color balance when mixing colors, and when mixing C, M, and Y colors, there was a lot of black.

In addition, as a means to solve this problem, a developing machine with BK (black) color toner in addition to C, M, and Y colors was installed.
Attempts have also been made to perform multiple exposures, but this has the drawbacks of increasing the size of the apparatus and slowing down the processing speed.

OBJECTS OF THE INVENTION The present invention is intended to overcome the various drawbacks mentioned above, and it is an object of the present invention to provide a multicolor printing device that can adjust the color balance of mixed colors without increasing the size of the device or reducing processing speed. The purpose is

Structure of the Invention The present invention provides a multicolor printing device equipped with a plurality of developing machines that develop each latent image formed in the form of a set of printing dots on a photoconductor in a different color by scanning with a plurality of optical systems. , a printing dot diameter changing means is provided in the middle of the optical path of each element system, and the printing dot diameter by the printing dot diameter changing means is changed depending on the type of color mixture to adjust the color balance of the mixture. We aim to achieve the above objectives in a transparent manner.

Embodiments of the Invention The present invention will now be described in detail with reference to FIGS. 2 and 6.

FIG. 2 shows latent image formation 9 by the optical system 21 to which the present invention is applied.
% is a perspective view showing the optical system 21, the laser 22, the beam compressor 25, and the module 1'24. ! :,
It is equipped with a beam expander 25, a prism box 26 which is a feature of Kienori, a cylindrical lens 27, a polygon mirror 29 driven by a mirror motor 2B, a toroidal lens 30, and a double spherical lens 51. .

The beam emitted by the laser 22 enters the polygon mirror 29 and is reflected as shown by the double dotted line in the figure, and the beam is reflected by the surface of the photosensitive drum 1 which is rotated by the drum motor 32 via the speed reduction mechanism 66. A latent image is formed by scanning the conductor.

In the present invention, the prism box 26 is provided between the laser 22 and the polygon mirror 29.

This prism box 26 has two built-in prisms 34 and 35 for changing the beam diameter (print dot diameter) during scanning, and is driven by a solenoid 36, as shown by the solid line and the vertical line in FIG. direction shown by the arrow in Figure 2 (6th
It can move forward and backward across the optical path in the direction perpendicular to the plane of the figure. When the prism box 26 driven by the solenoid 66 is positioned above in FIG. 2, the prism filter 4 is positioned on the optical path, and when the prism box 26 is positioned below in FIG. positioned on the road. Therefore, the print dot diameter changes when the prism 64 is positioned on the optical path and when the prism 35 is positioned on the optical path. This change in the print dot diameter is caused by a shift in the optical axes of the beams that enter in the direction of the arrow and exit from each prism in the same direction.

It has this kind of effect. A printing dot diameter changing means such as a prism box or a solenoid is provided in each optical system of the color electrophotographic apparatus.

Therefore, by using this print dot diameter changing means, it is possible to adjust the color balance of the mixed colors by changing the print dot diameter of each optical system depending on the type of color mixture.

If you want to make a certain color stronger in order to adjust the color balance, the procedure for selecting the printing dot diameter is as shown in the table below.

As shown in the table above, if you want to make the blue color stronger when mixing,
If you want to increase the print dot diameter of the C, M hue latent image forming optical system and reduce the print dot diameter of the Y colorant optical system, and make the green color stronger, increase the print dot diameter of the C, Y colorant. Y
If it is desired to make the colorant print dot diameter smaller and make the red color stronger, it is sufficient to increase the M and Y colorant print dot diameters and reduce the C color print dot diameter. It is also possible to obtain black by mixing C, M, and Y colors.

Effects of the Invention As described above, according to the present invention, the printing dot diameter of each optical system can be changed, so that
By appropriately introducing these diameters depending on the type of color mixture, it is possible to adjust the balance of the nine colors. Also, BK
Since it is not necessary to provide a developing machine with different color toners and perform brightening four times, it is possible to reduce the size of the apparatus and improve processing speed.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional multicolor printing device, Figures 2 and 6
The figure shows an embodiment of a multicolor printing device according to the present invention.
Figure 2 is a perspective view showing how to form a latent image using the optical system;
The figure is a shape diagram of a prism provided in a prism box. In the figure, 1 is a photosensitive drum, 20 is paper, 21 is an optical system, 2
6 is a prism box, 34 and 35 are prisms, 3
6 is a solenoid. Patent applicant Fujitsu Limited

Claims (1)

[Claims] In a multicolor printing device equipped with a plurality of developing machines that each develop a latent image formed in the form of a set of reverse printed dots on a photoconductor in a different color by the scanning of a plurality of optical systems, A multicolor printing device characterized in that a printing dot diameter changing means is provided in the middle to adjust the color balance of the mixed colors by changing the diameter of the printing dots according to the color mixture according to the type of color mixture.