JPS63316017A - Laser beam scanner - Google Patents

Abstract

PURPOSE:To shorten the time required to reach a rated rotating speed and to reduce the life and noises of a motor by controlling the motor into reduced rotation and controlling the motor to fast rated rotation when a start signal is inputted. CONSTITUTION:A control circuit 4 for the motor 2 which drives a rotary polygon mirror 1 is so constituted to control the motor to the slow rotation when no image signal is inputted and to the fast rated rotation when an image signal is inputted. Namely, the motor in the slow rotation is proceeded to the fast rotation with the start signal inputted prior to the input of the image signal and the pause state of the slow rotation is entered from the fast rotation when the input of the image signal is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser scanning device used in a laser printer or the like.

[Conventional technology]

As is well known, in a laser printer, a static 7Fi latent image is formed on the photosensitive drum surface by deflecting a laser beam modulated by a rotating polygon mirror using a rotating polygon mirror and scanning the photosensitive drum surface. It is constructed so that a visible image can be created by transferring the current image onto recording paper.

In such a laser printer, the rotating polygon mirror rotates at zero speed during an image recording operation. Therefore, the noise is too loud to ignore, and it also greatly affects the life of the motor that rotates the rotating polygon mirror.

Therefore, conventionally, in a standby state (hereinafter referred to as a pause state) other than when recording an image, the rotation of the rotating polygon mirror is stopped by an external control signal or command, which reduces the motor speed and noise. 1IIlIC as planned! Eleven circuit configurations are known.

(Problem that the invention is trying to solve) However, if the rotation of the rotating polygon mirror is stopped except when recording the image θ, it will take 5 hours to reach the high rated rotational speed. There was a problem in that the length of the laser printer became long, and the throughput as a laser printer decreased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser scanning device that can shorten the time it takes for a rotating polygon mirror to reach its rated rotational speed, and can also reduce motor life and noise.

(Means for Solving the Problems) In the present invention, the control circuit of the motor that drives the rotating polygon mirror is controlled to rotate at a low speed when no image signal is input (1), and the motor is controlled to rotate at a low speed when the image signal is not input. It is designed to control the rotation to a high speed rated rotation according to the input.

Specifically, the motor shifts from low-speed rotation to high-speed rotation in response to a start signal that is input prior to the input of the image signal, and returns from high-speed rotation to a paused state of low-speed rotation when the input of the image signal ends. It is.

[Function] When there is no need to record an image, the motor is controlled to rotate at a low speed, so that the noise and noise can be made smaller than when the motor rotates at a high speed. Furthermore, since the rotation speed is shifted to high speed upon the start of recording, the transition time is short and the throughput as a laser printer is not reduced.

〔Example〕

FIG. ff11 is a block diagram showing an embodiment of the present invention, and a motor 2 that rotationally drives the rotating polygon tu 1 is driven by a motor control signal MD output from a motor drive circuit 3. The motor drive circuit 3 is controlled into a stopped state and a rotating state by a motor on/off@tan MC3 inputted from a control circuit 4, and the rotational speed during rotation is controlled by a motor speed control signal MSP.

The control circuit 't84 generates motor on/off signals QMC8 and speed control 2II Shintan M based on each 1a@ signal inputted from an image signal generating device (not shown) such as a host computer.
The motor 2 is controlled by generating SP.

In addition to the image signal IMG, this control Ut+ circuit 4 receives a start signal ST as an image recording start command.

A pause speed setting signal PSP is input which instructs the rotation speed of the motor 2 at a low speed when the motor 2 is rotated at a low speed when an image is not recorded.

FIG. 2 is a climbing chart showing each stick up when recording an image corresponding to the image transmission IMG. In the pause state when not recording an image, the motor 2 is
), the motor is rotating at a low speed, but when the start signal ST is input to the control circuit 4, the control circuit 4 changes the motor speed to 1? The motor 2 is controlled via the motor control circuit 3 so as to be in a high speed rated rotation state by the IIIdtl signal MSP.

As a result, the motor 2 rapidly increases its rotational speed toward a constant speed rotation state, but at the timing shown in FIG. is input. And this image signal IMG
An image is formed by a recording system (not shown). after that,
When the input of the image signal IMG is completed, the control circuit 4 detects that the signal IMG is no longer input, and controls the motor 2 to a low speed rotation state using the motor speed control signal MSP.

After this, when the start signal ST is input again, the motor 2 is shifted to the rated rotation state in the same way, and the image signal IMG
When the input is completed, it returns to the low speed rotation state and stops.

The control circuit 4 repeats the motor control as described above depending on the input state of the start signal ST and the image signal IMG.
As shown in FIG. ff52 (d), when the pause control signal PC is input, the motor 2 is stopped. Therefore, when images are not recorded over a long period of time, the pause system @signal PC is input from the image signal generation device to A3 to completely stop the motor 2 and create a noiseless state. can.

In this case, if the motor 2 is completely stopped, it is possible that the motor 2 will not be able to reach the rated rotation state between when the start signal ST is input and when the imaging DIMG is input. There is also gender. Therefore, as shown in the timing chart of FIG. 3, the control circuit 4 of this embodiment starts the motor 2 to rotate at high speed based on this pause control signal F3Pce when the pause control signal PC rises before the start signal ST. Migrate. The rotation speed in this case is commanded by the pause speed setting signal PSP. Therefore, the signal PS
If the speed commanded by P is set to a speed higher than the rated circulation speed, the motor 2 can reach the rated rotational speed before the input of the image signal IMG starts, as shown in the timing chart of figure ff13.

Note that the rotational speed of the motor 2 when images are not recorded can be set not only to one type of low-speed rotation but also to an appropriate speed by the pause speed setting signal PSP. Therefore, it is possible to use the pause speed setting signal PSP to set the most effective motor speed for various lengths of time when images are not recorded, thereby reducing the lifespan of the motor 2 and noise without impairing the throughput. can prevent an increase in

Although the above embodiment has been described on the assumption that it is applied to a laser printer, it can be applied to any device that scans laser light using a rotating polygon mirror.

[Effects of the Invention] As explained above, according to the present invention, the rotating polygon mirror can be brought to the rated rotation state in a short time, so that the motor speed can be improved without reducing the throughput in a laser printer or the like. It is possible to reduce noise and prevent a decrease in direction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2, 3, and 3 are timing charts for explaining the operation of the embodiment. DESCRIPTION OF SYMBOLS 1...Rotating polygon mirror, 2...Motor, 3...Motor drive circuit, 4...Control circuit. Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) Equipped with a rotating polygon mirror, a motor that rotationally drives this rotating polygon mirror, and a control circuit that controls the rotation of this motor, the laser beam modulated with a desired image signal is deflected by the rotating polygon mirror. In a laser scanning device that scans a surface to be scanned, the control circuit monitors an image signal and a start signal that is inputted prior to inputting the image signal, and controls the control circuit before starting inputting the start signal and after inputting the image signal. A laser scanning device characterized in that the motor is controlled to rotate at a low speed, and when a start signal is input, the motor is controlled to a rated high speed rotation. (2) The control circuit is configured such that a rotational speed setting signal for low-speed rotation is externally input, and the rotational speed of the motor for low-speed rotation can be variably set by this rotational speed setting signal. A laser scanning device according to claim (1). (3) The control circuit is configured such that a control signal for controlling the rotation of the motor when no image signal is input is inputted from the outside, and the rotation of the motor can be controlled to a stopped state by inputting this control signal. A laser scanning device according to claim (1), characterized in that: