JPS59117372A - Electronic printer - Google Patents

Abstract

PURPOSE:To attain the print with high resolution by switching a dot pitch and a picture constituting dot number so as to control variably a beam diameter for obtaining an optimum beam diameter in response to the switching. CONSTITUTION:Driving circuits 1a-14a driving a laser generator 1, an acoustic optical modulator 3, a beam diameter switching mechanism 6, a mirror driving motor 9, and a drum driving motor 14 are connected to a control processor 18 and receive a command from a central processing unit CPU or a dot pitch selector switch 19. That is, the control processor 18 inputs a control signal to the driving circuits 1a-14a according to a program formed in advance based on an input signal of the dot pitch and other operating conditions, and further a video signal specifying the picture constitution dot number from pattern selecting buttons 17a-17c is inputted to a modulating circuit 3a via a dot pattern selecting circuit 17.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an electronic printer, and more particularly to an electrostatic printer that forms a latent image using dots irradiated with a radar beam.

(2) Background of the Technology In electronic printers, a large number of dots are formed on a photosensitive drum by laser beam irradiation, corresponding to characters (images) to be printed, thereby forming an electrostatic latent image. 1
When printing two images, the dot pitch is constant and 1
Of all the dots within the range constituting the image, dots at positions corresponding to the image are irradiated with the laser beam. In such electronic printers, there may be a request to print characters with different sizes. In such a case, drive and
It is desirable to obtain high-resolution printing by optimizing the parameter.

(3) Prior Art and Problems In conventional electronic printers, the dot pitch is fixed at a constant value, and therefore, when printing by reducing the size of characters, the resolution deteriorates and clear print cannot be obtained. Furthermore, the laser power, irradiation time, rotating mirror, drum rotation speed, etc. were each independently controlled, and the laser beam diameter was constant. Therefore, it has not been possible to automatically control other parameters to the optimum state corresponding to each driving parameter of the electronic printer.

(4) Purpose of the Invention The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is possible to switch the dot pitch and the number of dots constituting an image, and to adjust the beam diameter so that the optimum laser beam diameter can be obtained according to the switching. An object of the present invention is to provide an electronic printer that can obtain high-quality printing by making the drive parameters variable and controlling each driving parameter in relation to each other.

(5) Structure of the invention In order to achieve this object, the electronic printer according to the present invention comprises:
A laser light source for irradiating a latent image forming laser beam onto the photosensitive drum, a laser beam irradiation time interval adjustment means, a laser beam diameter adjustment means, a scanning mirror rotation motor, and a photosensitive drum rotation motor, It has a dot pitch selection means and an image composition dot number selection means, and according to a selection signal from the dot pitch selection means and the image composition dot number selection means, according to a predetermined program, the power control for the laser beam generation, and the above Control for controlling the drive of the laser beam irradiation time interval adjustment means, the drive control of the laser beam diameter adjustment means, the rotation speed control of the scanning mirror rotation motor, and the rotation speed control of the photosensitive drum rotation motor. have the means.

(6) Embodiment of the Invention FIG. 1 is a block diagram of an example of an electronic printer according to the present invention. A beam compressor 2, an acousto-optic modulator (Acoustic-o
optical modulator (AOM) 3, beam extender/4' under 4, beam diameter switching prism? 5, a cylindrical lens 7 for beam correction, a polygon mirror 8 for scanning, a toroidal lens 10 for beam irradiation position correction, and an fθ lens 11 for scanning speed correction.
The laser beam scans the surface of the photosensitive drum 12 to form a latent image in the form of dots.

The AOM 3 periodically changes the laser optical path according to the frequency, and is a means for adjusting the time interval of the laser beam passing through a predetermined optical path by changing the frequency. The prism GEX 5 includes, for example, a pair of prisms 15 and 16 as shown in FIG. 2, and is used to enlarge the diameter of a laser beam passing through the prisms 15 and 16. The prism index 5 has a plurality of pairs of prisms having different shapes, and a switching mechanism 6 switches the laser beam diameter by switching the prisms. Instead of using a prism as a means for changing the beam diameter, a variable slit means capable of adjusting the slit width may be used. ? The ribbon mirror 8 is driven by a drive motor 9 for multiple rotations, and the reflected laser beam is swung to scan the photosensitive drum 12. The photosensitive drum 12 is driven multiple rotations by a drive motor 14 via a deceleration mechanism 13 .

The electronic printer having such a configuration is driven and controlled by a control means that performs control according to a preset program based on a relational expression between parameters of each drive unit as shown below. A.O.
The modulation frequency of M3 is f (H2), the irradiation beam diameter (1/
e2) as d (mm), main scanning speed in the beam scanning direction as V (mm/s), sub-scanning speed in the drum rotation direction as v (-/s), laser power t-P (mW),
The dot pitch in the main scanning direction is Prn (Tran), the dot pitch in the sub-scanning direction is P8 (pieces), the light energy on the electrostatic drum is E (p J 7cm2), and the N scanning width is W (mm).
), then in the case of normal development, experimental shea = 164xp, ...
・Print quality is best when it is at the peak (1).

In addition, from the definition, Pm=v/f...Song (2)
P, = v X W / V・Song interval (3) E = k
A relational expression is determined:

FIG. 3 is a control circuit diagram of the electronic printer according to the present invention. The laser generator 1 is driven by a laser generation drive circuit 1a, the AOM 3 is driven by a modulation circuit 3a, the beam diameter switching mechanism 6 is driven by a switching drive circuit 6a, and the mirror drive motor 9 is driven by a mirror drive circuit 9a. is driven,
The drum drive motor 14 is driven by a drum 1 drive circuit 14a.

Each drive circuit 1a+3a+6a, 9a+14m is connected to a control processor 18, and a dot pitch selector switch 19 and a central control unit (CPU') are connected to the control processor 18 so that a desired dot pitch can be set manually or by a command from the central control unit. Multiple inputs are received. Based on this dot pitch input signal and other operating and driving conditions, the control processor 18 sends a power control signal to the laser generation drive circuit 1a and a power control signal to the modulation circuit 39 according to a program prepared in advance according to equations (1) to (4) above. On the other hand, the switching drive circuit 6 changes the clock signal for modulation.
A switching position signal is input to a, and a motor drive clock signal is input to each of the mirror drive circuit and drum drive circuit. The modulation circuit 3a is connected to the turn selection buttons 17a, 17b, and 17c via the turn selection circuit 17. The number of image constituent dots (for example, 32.times.32.64.times.64, etc.) is specified by this /'P turn selection detonation, and a video signal is input to the modulation circuit 3a. A specific example of control using the above formulas (1) to (4) is shown below. Consider a case where the dot pitch is designated as P (mm) by the dot pitch selector switch 19. now,
Let paste = P and = P. In any of the following cases, the prism switching 1 drive circuit 6a is controlled so that d=1.64XP according to equation (1), and the beam diameter is optimized.

E is kept constant to form a latent image.

mw, vf! When r is constant, the clock signal for driving the mirror motor is controlled so that v=2 from -W (3).

-W From (2), the modulation clock 2 is set so that f=□. Control the ivy signal.

(fI) When W and f are constant, the clock signal for driving the mirror motor is controlled so that I) V=f-P according to (2).

From f, p2 (3), the drum motor driving clock signal is controlled to be v-7.

From (4), the laser generated power is controlled so that P=1·f −E −p2.

Qll) When P-V-v is constant, from (4), once v-W= is constant...
(5) Substitute into (3) and control the mirror motor and drive clock signal for P so that v=once once.

(2) The clock signal for modulation P2 is controlled so that f=k-P·1.

(5) YosiW=ni! It becomes l-.1 (printing width changes).

(7) As described in detail of the invention, in the electronic printer according to the present invention, the laser beam diameter switching means (i.e., It controls the power generated, the modulation signal for adjusting the laser irradiation time interval, the beam diameter switching signal, and the drive signals for the mirror motor and drum motor.Therefore, printing in the desired shape can be obtained with high resolution, and each drive unit of the electronic printer can be operated efficiently in optimal conditions, improving printing quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electronic printer according to the present invention, FIG. 2 is a block diagram of an example of a beam diameter switching prism according to the present invention,
FIG. 3 is a control circuit diagram of the electronic printer according to the present invention. l... Laser generator, 3... AOM, 5... Prism box, 6... Prism switching mechanism, 8...
Polygon mirror, 9...mirror drive motor, 1♀...
Photosensitive drum, 14...Drum, drive motor, 17...
1,000 turn selection circuit, 18... control processor, 19... dot pitch selector switch. Patent applicant Fujitsu Limited Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate 1) Yukio Patent attorney Akiyuki Yamaguchi No. 10 Figure 3

Claims (1)

[Claims] 1. a Rade light source for irradiating a latent image forming laser beam onto a latent image forming medium; a laser beam irradiation time interval adjusting means;
It is equipped with a laser beam diameter adjusting means, a scanning mirror rotation motor, and a latent image forming medium driving motor, and has a dot pitch selection means and an image composition dot number selection means, the dot pitch selection means and the image composition dot number selection means In response to a selection signal from, according to a predetermined program, the power control for laser beam generation, the drive control of the laser beam irradiation time interval adjustment means, the one-view control of the laser beam diameter adjustment means, and the An electronic printer comprising control means for controlling the rotational speed of a mirror rotation motor, and controlling the rotational speed of the latent image forming medium and drive motor.