JPS60113264A - Multicolor laser beam printer - Google Patents

Abstract

PURPOSE:To simplify the constitution, to reduce the cost, and to improve the reliability and the maintainability of the titled printer by setting the length from the exposure point of each of drums, which transfer plural colors, to the transfer point to a prescribed value. CONSTITUTION:The output picture signal of a character generator 5 is applied simultaneously to optical modulators 6 and 7 and is modulated optically by lasers 1 and 2 simultaneously. Peripheral speeds of photosensitive drums 3 and 10 to a print form are equal to each other, and a latent image exposed at a point C of the drum 3 is transferred at a point A and is carried for a length z1. Meanwhile, a latent image exposed at a point D of the drum 10 is turned for a length X1 and reaches a point B. When the length from the exposure point to the transfer position on the drum 3 is denoted as Y1, the image transferred at the point A coincides the other image at the point B because a length x1 is equal to a length (y1+z1) and peripheral speeds of drums 3 and 10 are equal to each other, and thus, positions of images of two colors coincide with each other without a delay circuit.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a multicolor laser beam printer that enables multicolor transfer alignment by setting the exposure points and transfer positions of a plurality of photoreceptor belts or photoreceptor drums. .

[Prior art]

As a conventional multicolor laser beam printer, for example, the first
There is one shown in the figure. This laser beam printer uses first and second lasers 1 and 2 to generate laser beams, and develops and transfers an electrostatic latent image formed by the laser beam of laser 1 with toner of a first color. A first photoreceptor drum 3, a second photoreceptor drum 4 which develops and transfers an electrostatic latent image formed by the laser beam of the laser 2 with a second color toner, and an input signal. a character generator 5 that outputs an image signal for each color based on the image signals of the character generator 5, optical modulators 6 and 7 that modulates laser light based on the image signal of the character generator 5, and a drum that outputs image signals for the phototransformer 7 From transfer position 3 to drum 4
It is comprised of a delay circuit 8 that delays the time until the print paper is conveyed to the transfer position.

In the above configuration, when a modulated input signal is received, it is demodulated into an image signal and sent from the character generator 5 to the light modulator 6 and delay circuit 8.

The optical modulator 6 optically modulates the laser beam from the laser 1 according to the image signal of the first color to form an electrostatic latent image on the photoreceptor drum 3. On the other hand, the delay circuit 8 delays the supplied image signal of the second color by the time required for the printing paper to reach the photosensitive drum 4 from the photosensitive drum 3 and sends it to the optical modulator 7 . Based on this image signal, the optical modulator 7 modulates the laser tip light of the laser v'2 to form an electrostatic latent image on the photosensitive drum 4.

The photoreceptor drum 3 develops the electrostatic latent image with a first color toner and transfers it to print paper, and the photoreceptor drum 4 develops the electrostatic latent image with a second color toner and transfers it to the photoreceptor drum. 3. Therefore, the two colors are transferred to the same position of the transferred image without any color shift◇ However, in conventional multicolor laser beam printers,
For the drum that performs the second transfer, the entire video signal must be delayed using a delay circuit to align the transfer of the two colors, which complicates the configuration of the device, increases costs, and reduces reliability and maintenance. [Objective and Structure of the Invention] The present invention has been made in view of the above, and is designed to avoid positioning of each drum, etc. that transfers multiple colors, by signal delay processing. In order to simplify the configuration, between multiple photoreceptors (drums or belts), the distance from the exposure point of the photoreceptor to the transfer point to the photoreceptor that will be transferred in advance is To provide a multicolor laser beam printer in which the distance from an exposure point to a transfer point is equal to the sum of the distance between both transfer points.

〔Example〕

Hereinafter, the multicolor laser beam printer according to the present invention will be described in detail using an example of printing two colors.

FIG. 2 shows an embodiment of the present invention. The same parts as in FIG. The drum 4 is used instead of the photosensitive drum 1O, which directly supplies the first color to the photosensitive drum 7 and develops and transfers the second color, which has a different drum diameter, to the photosensitive drum 3. It has a composition with a cast of characters.

As shown in FIG. 2, from the exposure point of the photosensitive drum 10 (the position where the modulated laser light reaches the drum surface)
When the distance im from 1 to 1 is "Is", the distance from the exposure point of photoreceptor Cyrano 3 to the transfer position is yl, and the distance between the transfer positions of photoreceptor drum 3 and 10 is 21, the relationship between each fFJ is expressed as follows: Determined by formula.

xs:yt ten zl In other words, the photosensitive drum 3 is transferred at the transfer position B of the photosensitive drum 10.
The two colors can be aligned by aligning the exposure point of the photosensitive drum 1o with the exposure point of the photosensitive drum 1o at the same position on the printing paper surface.

In the above configuration, the image signals output from the character generator fi5 are simultaneously applied to the optical modulators 6 and 7, and optical modulation is simultaneously performed on the laser beams from the lasers 1 and 2. The peripheral speeds of the photoreceptor drum 3 and lO with respect to the print paper are the same, and the latent image exposed at point 0 of the photoreceptor drum 3 is transferred to the copy paper at point A, which is the same as the peripheral speed of the photoreceptor drum 3. It is transported at a speed of a distance zs't-times@Meanwhile, at the same time as the 0 point of the photoreceptor drum 3 is exposed, the D point of the photoreceptor drum 10 is exposed, and the latent image due to this exposure is transported a distance xt-times. movement (7) and reaches point B. This distance x1 is (Y
Since the length of the latent image formed at point A and the image formed at point 0 are equal to the length of the latent image (after transfer) and the circumferential speeds of the photoreceptor drums 3 and 10 are the same, image) is merged at point B, and the photoreceptor drum 10 is transferred onto the transfer image surface of the photoreceptor drum 30,
Two-color images can be aligned without using a delay circuit.

FIG. 3 shows another embodiment of the present invention, in which the same parts as in FIG. are placed close together.

Even if the two photoreceptor drums have the same diameter, if the distance between them is small, (y*+z)=x
2 does not exceed the outer circumference of the photoreceptor drum 4,
Two colors can be aligned in the same position, and if there is enough space to be close to the drum house, it is possible to rent the same drum diameter.

What? In the above explanation, we have shown an example in which two photoconductor drums are arranged in series in the paper feed direction υ to perform two-color printing. Multicolor printing can be performed by setting the drum diameter and position to satisfy the following.

-Also, instead of a photoreceptor drum, a device with a photoreceptor on the surface can be used.
It is also possible to use a photoreceptor belt made of

〔Effect of the invention〕

As explained above, according to the multicolor laser beam printer of the present invention, between a plurality of photoconductors (drums or belts), the distance from the exposure point of the photoconductor to the transfer point for subsequent transfer is determined in advance. The distance from the exposure point of the photoreceptor to the transfer point is the sum of the distance between the two turned ears, simplifying the configuration, reducing cost increases, and improving reliability and maintainability. I'm excited to try something.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional multicolor laser beam printer, and FIGS. 2 and 3 are block diagrams of two embodiments of the present invention. Explanation of symbols 1.2... Laser, 3.10... Photosensitive drum, 5
...character generator, 6,7...light modulator. Figure 1 Figure 3

Claims (1)

[Claims] Laser light is modulated for each color according to the recorded information, and the corresponding photoreceptor drum or photoreceptor belt is exposed to form an electrostatic latent image for each color, which is developed with toner of each color and placed on print paper. In a multi-color printer that transfers sequentially at the timing of A multicolor laser beam printer characterized in that the distance from the exposure point to the transfer position is the sum of the distance between both rotation positions.