JPS63199378A - Multicolor image 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 (Field of Industrial Application) The present invention relates to a multicolor image recording apparatus that performs multicolor printing.

(Prior Art) To explain a two-color electrophotographic device as an example of a conventional multicolor image recording device, a first exposure is performed on a uniformly charged photosensitive drum (electrostatic latent image holder) to record a first image. forming an electrostatic latent image, developing it to form a first toner image, and then performing a second exposure to form a second electrostatic latent image, which is different from the first toner image; Develop with a second toner of color and apply the second one to
After forming a toner image, it is transferred to printing paper and fixed, and two-color printing is performed in one recording cycle.

A spot on the photosensitive drum by the first laser beam for forming a first electrostatic latent image, and a spot on the photosensitive drum by the second laser beam for forming a second electrostatic latent image. and were constructed to be exactly the same in size and shape.

(Problem to be Solved by the Invention) However, in a two-color electrophotographic apparatus having the configuration as described in section 2, even if the diameters of the first and second laser beam spots on the photosensitive drum are the same, Because the toner adhesion amount may be different due to the difference in the components of the first and second color toners, the spot diameters of the first 1 to toner image and the second toner image do not match. color and second
There were some problems such as the printed line widths of different colors.

In addition, even if the spot diameters of toner images of each color are formed to be the same, due to differences in brightness and color or toner components, some colors are more noticeable and others are less noticeable, especially for black. There was also the problem that many colors were difficult to stand out.

In view of these problems, the present invention improves the image quality balance between each color image in a multicolor composite image by variably adjusting the spot size or spot shape of the laser beam irradiated onto the photosensitive drum. It is an object of the present invention to provide a multicolor image recording device that can perform multicolor image recording.

(Means for Solving the Problems) In order to achieve the above object, the first invention provides two types of electrostatic latent images formed on an electrostatic latent image holder based on different image signals. In a multicolor image recording device configured to form a two-color image by developing with toners of different colors, the spot sizes of two types of laser beams for forming each of the electrostatic latent images can be variably adjusted to each other. According to the second invention, the spot shapes of the two types of laser beams can be variably adjusted to each other.

(Example) Embodiments of the present invention will be described below based on the drawings.

The first section shows the main parts of the multicolor image recording device according to the first invention, where l is a photosensitive drum (electrostatic latent image holder) uniformly charged by a charger (not shown), 9 .10 are a first color laser and a second color laser that serve as light emission sources, and the first color laser emitted from these lasers 9 and 0 respectively
The color laser beam 5 and the second color laser beam 6 are separated by different angles of incidence on the polygon mirror 2, and are irradiated onto the photosensitive drum 1 through each reflection mirror 3.4, respectively, to form a predetermined electrostatic latent image. Ru. Then, toners of different colors are attached to these electrostatic latent images by a developing device (not shown) to form a toner image. Next, each toner image is transferred to printing paper, and then transferred to a fixing device. ~ fixed to a color image or printed paper.

By the way, one of the above reflecting mirrors 4 is configured to be movable in the traveling direction of the second color laser beam 6, and the diameter of the laser beam spot irradiated onto the photosensitive drum 1 changes depending on the amount of movement thereof. Therefore, the spot size of the electrostatic latent image formed can also be changed. For example, the first
Depending on the position of the reflecting mirrors 4.4', 4'' in the figure,
The spot size of the electrostatic latent image formed on the photosensitive tram 1 changes as shown by ■, ■, and ■ in FIG. 2, respectively. Therefore, for example, due to the difference in the components of the first color toner and the second color toner, a difference occurs in the amount of toner adhering to each electrostatic latent image. Even if the diameter or even the printing line width does not match,
By finely adjusting the position of the reflecting mirror 4 in advance to adjust the spot size of the electrostatic latent image formed on the photosensitive drum 1, it is possible to make the print line widths the same.

In addition, for example, if the printing accuracy requirements for the second color are less demanding than for the first color, the laser irradiation time can be shortened by increasing the spot size of the second color relative to the spot size of the first color. It is possible to aim for That is, if the image shown in Figure 3 (A) is created using the spot size shown in Figure 2 @ for the first color, then the second color is created by adjusting the reflective mirror to the 4'' position. The size is shown in Figure 2■
This spot size can be used to create an image as shown in Figure 3 (B), which reduces the number of spots within the same area and shortens the laser irradiation time. be able to.

Furthermore, by increasing the spot size of a color in which another color is less conspicuous than a certain color, the image quality of each hue pressure can be balanced.

Next, an embodiment of the second invention will be described with reference to FIGS. 4 and 5. In this embodiment, the first color optical system and the second color optical system have independent configurations. That is, the laser beams 15° 16 emitted from the first color laser 19 and the second color laser 20 are transmitted to separate polygon mirrors 11.12, fO lenses 13.14, and reflection mirrors 1, respectively.
The light is irradiated onto the photosensitive drum 1 through 7°18. A cylindrical lens 21 is provided near the exit of the laser 19 in one of the optical systems (the first color system in the figure), and by passing one of the laser beams 15 through the cylindrical lens 21, a circular beam is formed. The pot is deformed into an oval shape. Note that which of the horizontal axis and the vertical axis should be the long axis of the ellipse can be freely selected by using image raw data.

FIG. 5 shows the shape of the beam pot formed by this example. ■ is the spot shape when no deformation is performed;
(2) and (2) respectively show the spot shapes when deformed into elliptical shapes using the cylindrical lens 21, and are rotated by 90 degrees from each other according to the image raw data. That is, ■ is transformed into an ellipse with its major axis in the main scanning direction (horizontal direction) of the beam, and ■ is transformed into an ellipse with its major axis in the sub-scanning direction (vertical direction) of the beam.

By changing the shape of the beam spot on the photosensitive drum as described above, it is possible to achieve the same effect as in the first invention in which the size of the beam spot is changed.

In all of the above embodiments, the size or shape of the beam spot is changed for only one color, but it is of course possible to change the size or shape for both colors. It is.

(Effects of the Invention) As explained below, in the present invention, the spot shape of each laser beam for forming two types of electrostatic latent images is configured to be variably adjustable, so that multicolor synthesis is possible. It is possible to improve the image quality balance between each color image in the image.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of the multicolor image recording apparatus according to the first invention, FIG. 2 is a diagram showing each beam spot size at the positions ■ to ■ in FIG. 1, FIG. 3 (A), (B) is a diagram showing examples of formed images, FIG. 4 is a perspective view of main parts of a multicolor image recording device according to the second invention, and FIG. 5 is a diagram showing various beam spot shapes formed by the same device. It is a diagram. 1... Photosensitive drum (electrostatic latent image holder), 3,4°17
．． 18... Reflection mirror, 5, 6, 15. 16... Laser beam, 9, 10, 19. 20... Laser, 21
...Cylindrical lens.

Claims (4)

[Claims] (1) A multi-layer system configured to develop two types of electrostatic latent images formed on an electrostatic latent image holder based on different image signals with toners of different colors to form a two-color image. A multicolor image recording apparatus, characterized in that the spot sizes of the two types of laser beams for forming each of the electrostatic latent images can be variably adjusted to each other. (2) Two types of electrostatic latent images formed on the electrostatic latent image carrier based on different image signals are developed with toners of different colors to form a two-color image. A multicolor image recording apparatus, characterized in that the spot shapes of the two types of laser beams for forming each of the electrostatic latent images can be variably adjusted to each other. (3) The multicolor image recording device according to claim 2, wherein at least one of the two types of laser beams has a spot shape of an ellipse having a long axis in the beam main scanning direction. (4) The multicolor image recording apparatus according to claim 2, wherein the spot shape of at least one of the two types of laser beams is an ellipse having a long axis in the sub-scanning direction of the beam.