JPS62160472A - Laser recording device - Google Patents

Abstract

PURPOSE:To prevent a semiconductor laser and a scanner motor from deteriorating and to reduce noises by reducing a recording laser generation output and lowering a scanning speed in nonprinting mode. CONSTITUTION:When a pring signal and a ready signal both rise to H and a nonprint state is changed into a print state, relays RY1, RY2 and RY3 are excited. Then, the uninverted input potential of an operational amplifier drops through the relay RY1, the output current of the amplifier A1 decreases and the collector current of a transistor (TR) Q1 increases. Consequently, the output of an LEDLD 1 for recording laser light increases. The scanner motor 28 is changed from low-speed driving to high-speed driving through relays RY2 and RY3, etc., with driving pulses sent from a frequency divider 50 without being passed through a frequency divider 52. Consequently, the power consumption of the semiconductor laser and scan motor in nonprinting mode is reduced to prevent the both from deteriorating and noises of the scan motor in nonprinting mode are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a laser recording device such as a laser printer or a laser plotter used as an output device of an information processing system. This invention relates to a laser recording device in which the driving speed of a scanning means that scans over a recording medium is adjusted to m (2) T 7F.

Prior Art In conventional laser printers, the output power of the laser generating means such as a semiconductor laser that generates laser light is always regulated when the printer's main power is on, regardless of whether printing is being performed or not. It was outputting with the power of. Furthermore, the scanner motor that drives the polygon mirror that scans the laser beam always rotates at a specified rotation speed when the power is on and even when no printing is being performed.

Therefore, the semiconductor laser and the scanner motor deteriorate quickly, resulting in a shortened service life.

Furthermore, in high-speed printers, the scanner motor always rotates at high speed, which has the disadvantage of increasing wind noise from the polygon mirror and noise from the polygon motor.

In order to eliminate this drawback, when not printing while waiting for data from the host, the output of the semiconductor laser and the rotation of the scanner motor are stopped, and the output of the semiconductor laser is output by the print request signal, and the rotation of the scanner motor is stopped. You can think of something that rotates. In such devices, it takes a long time for the output of the semiconductor laser to reach the specified power and the rotation speed of the scanner motor to reach the specified rotation speed and stabilize, so the first print after waiting for data from the host This has the disadvantage that printing is delayed and printing efficiency is reduced.

Purpose The present invention eliminates the drawbacks of the prior art, and provides a laser recording device that can prevent deterioration of the semiconductor laser and scanner motor, extend their lifespan, and prevent noise when not printing. The purpose is to provide

Configuration In order to achieve the above object, the present invention includes a laser generating means that generates a laser beam, a means that modulates the laser beam with an image signal, and a scanning device that performs exposure by scanning the laser beam onto a conveyed recording medium. and a control means for controlling each means, in which the control means scans a recording medium with laser light modulated by the modulation means and performs recording according to an image signal. At times, the output of the laser generating means is controlled to be lower than that during printing, and the scanning speed of the scanning means is controlled to be lower than that during printing. Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

FIG. 2 shows a schematic configuration diagram of a laser printer.

The recording medium 2 is conveyed in the direction of arrow F by the drive motor.
It is uniformly charged by a corona discharge or the like in a charging section 4, exposed to light according to an image signal in an exposure section 8, developed with toner in a developing section 8, and transferred to paper 11 with a toner image in a transfer section 10.
The charge is removed by light or corona discharge of opposite polarity in the charge removal section 12, cleaned by the cleaning section 14, and uniformly charged again by the charge section 4.

The generating section and the scanning exposure section are shown.

Laser light generated from the semiconductor laser LD20 is modulated by an LD driver 22 according to an image signal, and is scanned by a polygon mirror 24 to form an electrostatic latent image on the recording medium 2. The recording medium 2 is conveyed in the direction of arrow F (sub-scanning), and the laser beam is scanned in the direction of arrow S (main-scanning).

The main scanning by the polygon mirror 24 is synchronized in timing in the main scanning direction by detecting laser light by a synchronization detection section 28 provided at the side end of the recording medium 2. The synchronization detection section 26 detects light received by a photodiode PD2, which will be described later.

A scanner motor 28 connected to the polygon mirror 24 is connected to a scanner motor driver 30.

In the embodiment shown in FIG. 3, a polygon mirror 24 and a scanner monitor 28 for driving the polygon mirror 24 are used, or other means of laser scanning may be used. +4h eggplant booklet...
In this embodiment, in the exposure section of such a laser recording apparatus, the output of the semiconductor laser LD 20 that generates the laser beam and the rotation speed of the scanner motor 28 of the polygon mirror 24 that scans and exposes the laser beam are adjusted to fjl.
It is a device that performs m.

FIG. 1 shows an embodiment of a circuit for controlling the output of a semiconductor laser LD 20 and the rotational speed of a scanner motor 28 of a laser printer such as the one shown in FIG.

The two input terminals of the AND circuit 40 are connected to a host (not shown) so that a print signal and a ready signal are input.The output of the AND circuit 40 is connected to a relay RY.
Connected to I, RY2, RY3, AND circuit 4
When the output of 0 is high level, relays RYI, RY2,
RY3 is each closed, and when the output is at a low level, relays RYI, RY2, and RY3 are each opened. Figure 1 shows relays RYI, RY2, RY
3 indicates that all are open.

One terminal of the relay RYI is connected to a positive power supply v1 via a resistor R1 and also to a non-inverting input of an operational amplifier A1, and the other terminal is grounded via a resistor R2. Resistor R3 is connected to relay RYL and resistor R2.
are connected in parallel. The output from the OA converter 42 is input to the inverting input of the operational amplifier AI.

The output of the operational amplifier AI is connected to the base of the transistor Q1 via a resistor R4, and is also connected to the inverting input terminal of the operational amplifier A1 via a resistor R5. The emitter of transistor Ql is connected to power supply Vl via resistor R8R7. Further, the collector of the transistor Ql is connected to a light emitting diode LDI constituting the semiconductor laser LD20, and the other terminal of the light emitting diode LDI is grounded.

The light receiving diode PDI receives light generated from the light emitting diode LDI, and one terminal thereof is connected to the inverting input of the operational amplifier A2.

The non-inverting input of operational amplifier A2 is grounded.

The output of the operational amplifier A2 is connected to the non-inverting input of the operational amplifier A3, and is also connected to the inverting input terminal of the operational amplifier A2 via a variable resistor VRI.

The inverting input terminal of operational amplifier A3 is connected to negative polarity power supply -v2 via resistor R8.

The output of the operational amplifier A3 is input to the gate array 44, and the output of the gate array 44 is input to the OA converter 42.
The outputs of the OA converters 42 are respectively connected to the inverting input terminals of the operational amplifiers AI.

The light receiving diode PD2 is provided in the synchronization detecting section 2B of FIG. 3 and detects the laser light generated from one light emitting diode LDI. The synchronization detection circuit 27 is provided in the synchronization detection section 2B of FIG. 3, and detects the synchronization timing of the main scanning of the laser light received by the light receiving diode LDI. Delay circuit 4
6 delays the LD modulation signal that modulates the laser beam in accordance with the main scanning synchronization timing detected by the synchronization detection circuit 27. That is, when printing, the time interval of the synchronization signal detected by the synchronization detection circuit 27 is short, so the LD modulation signal is sent as is to the light emitting diode LDI, and when not printing, the time interval of the synchronization signal is long, so the LD modulation signal is delayed. and sends it to the light emitting diode LDI. With this, 11Ab-711+-L+tk^-! zu”the!10
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This is done in the entire main scanning direction of 2, and there is no unexposed portion.

The output of oscillator 48 is connected to the input of frequency divider 50, and the output of frequency divider 50 is connected to relays RY2 and RY3. The relay RY2 is connected to the scanner motor driver 30 via the frequency divider 52 when it is open as shown in the figure, and directly to the scanner motor driver 3G when it is closed. Relay RY3
is connected to the frequency divider 52 via the PLL control circuit 5B when it is open as shown, and is connected to the relay RY2 via the PLL control circuit 58 when it is closed. Scanner motor driver 30 is connected to scanner motor 28 and drives scanner motor 28 .

Explain the operation.

When one or both of the print signal and ready signal is low level, that is, the printer is in a busy state from when the power is turned on until printing becomes possible, and no print signal is input even though printing is possible. In the ready state, the output of the AND circuit 40 becomes low level and the relay RYI is opened. Since the potential of the non-inverting input of L± operational amplifier At rises in 1 mins of relay RYI, assuming that the potential of the inverting input is constant, the output current of operational amplifier At increases, and transistor Q1
The base potential of increases. Therefore, transistor Q
Since the collector current of the light emitting diode LDI decreases and the current flowing through the light emitting diode LDI also decreases, the amount of light generated from the light emitting diode LDI decreases, and the laser power of the laser generating means decreases. In this manner, the laser power is kept low during non-printing times. It is preferable that the laser power during non-printing times be as small as possible and equal to or higher than the minimum light receiving sensitivity of the photodiodes pD1 and PO2.

When both the print signal and the ready signal are at the noise level, that is, when printing
is closed. Operational amplifier A when relay RYI is closed.
Since the potential of the non-inverting input of I decreases, assuming that the potential of the 1-inverting input is constant, the output current of operational amplifier AI decreases, and the base potential of transistor Ql decreases. Therefore, the collector current of transistor Q1 increases,
Since the current flowing through the light emitting diode LDI also increases, the amount of light generated from the light emitting diode LDI decreases.
The laser power of the radar generating means increases. In this way, when printing, the laser power is increased to a specified amount.

When the light generated from the light emitting diode LDI changes and decreases, the amount of light received by the photodiode PDI that receives the light decreases. As a result, the amount of current flowing to the inverting input of operational amplifier A2 decreases, and the output of operational amplifier A2 becomes close to zero. At this time, the output of the operational amplifier A3 becomes larger than when the amount of light received by the photodiode PDI, which will be described later, increases, and this large output is digitally converted by the gate array 44, converted into an analog quantity by the OA converter 42, and then output by the operational amplifier AI. Human input is applied to the reverse input.

Therefore, since the potential of the inverting input of the operational amplifier A1 increases, the output current of the operational amplifier A1 decreases, and the base position of the transistor Q1 decreases. Therefore, the collector current of the transistor Q1 increases and the current flowing through the light emitting diode LDI also increases, so that the amount of light generated from one light emitting diode LDI increases. In this way, when a change occurs in which the amount of light generated from the light emitting diode LI)1 decreases, the change is compensated for and the amount of light generated is kept constant as described above. There is.

When the amount of light generated from the light emitting diode LDI changes and increases, the amount of light received by the photodiode PDI increases. As a result, the amount of current flowing into the inverting input of operational amplifier A2 increases, and the output of operational amplifier A2 becomes negative in polarity. At this time, the output of the operational amplifier A3 becomes smaller than when the amount of light received by the photodiode PDI described above decreases, and this small output is digitally converted by the gate array 44, converted into an analog quantity by the OA converter 42, and then output by the operational amplifier A1. Input to the inverting input. Therefore, since the potential of the inverting input of the operational amplifier AI decreases, the output current of the operational amplifier A1 increases, and the base potential of the transistor Ql increases. Therefore,
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Since the current flowing through the light emitting diode LDI also decreases, the amount of light generated from the light emitting diode LDI decreases.

In this way, when the beam of light generated from one light emitting diode LDI changes, it is automatically adjusted to maintain the amount of light at a specified amount during printing or at a low output amount when not printing.

Next, the operation of the speed control circuit of the scanner motor 28 will be explained.

When one or both of the print signal and ready signal is at a low level, that is, the printer is in a busy state from when the power is turned on until printing becomes possible, and the print signal is not input even though printing is enabled. In the ready state, the output of AND circuit 40 becomes low level and relays RY2 and RY3 are opened as shown in the figure. Therefore, the frequency signal output from the oscillator 48 is divided by the frequency dividers 50 and 52 to become a low frequency signal, which is kept constant by the PLL control circuit 56. This low frequency signal is output to the scanner motor driver 30, and the scanner motor driver 30 rotates the scanner motor 28 at a low rotation speed.

Furthermore, when both the print signal and the ready signal are at a high level, that is, when printing is performed, the output of the AND circuit 40 is at a high level, and relays RY2 and R
Y3 is closed in a state opposite to that shown in the figure. Therefore, the frequency signal output from the oscillator 48 is divided by the frequency divider 50 and kept constant by the PLL control circuit 58. Therefore, a higher frequency signal is kept constant by the PLL control circuit 58 compared to the open state of the relays RY2 and RY3. This signal is the scanner motor driver 30
is output to.

The scanner motor driver 30 rotates the scanner motor 28 at a specified number of rotations.

According to this embodiment, the output power of the light emitting diode LDI is low when not printing, and high when printing, so the light emitting diode LDI has a low output power when not printing, and a high output when printing. LI)1
can prevent deterioration and extend its life.

Similarly, the scanner motor 28 that drives the polygon mirror 24 that scans the laser beam is rotated at a low rotation speed when not printing, and at a high speed when printing, which prevents deterioration of the scanner motor 28 and extends its life. This can prevent the wind noise of the polygon mirror 24 and the noise of the scanner motor 28 from increasing when not printing. Moreover, when printing the output power of the light emitting diode LDI and the rotation speed of the scanner motor 28,
Since the power or speed can be maintained at a predetermined level when not printing, stable printing and pre-exposure can be performed.

Furthermore, since the exposure time of the main scan of the laser beam by the polygon mirror 24 is set long during non-printing, even though the rotation speed of the polygon mirror 24 is low, the main scan of the recording medium 2 The entire scanning direction can be exposed, and the preprocessing will not be incomplete.

Effects According to the present invention, the output power of the laser generating means is low when not printing and high when printing.
It is possible to prevent deterioration of the light emitting means and extend its life.

Furthermore, since the scanning means for scanning the laser beam is driven at a low speed when not printing and at a high speed when printing, deterioration can be prevented, the service life can be extended, and there is less noise when not printing.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a control circuit of a laser recording apparatus according to the present invention, FIG. 2 is a schematic configuration diagram of a laser printer, and FIG. 3 is a diagram of an exposure section of the laser printer shown in FIG. It is a schematic block diagram. Explanation of symbols of main parts 2...Recording body 20...Semiconductor laser 24...Polygon mirror 2f1. . . . Synchronization detection unit 28 . . Scanner motor 30 . . . Scanner motor driver 40 . . . AND circuit 4B . . Delay circuit 48 . Control circuits RYI, RY2. RY3...Li-AI, A2
．． A3. ... operational amplifier

Claims (1)

[Claims] 1. Laser generating means for generating laser light, means for modulating the laser light with an image signal, and scanning means for scanning the laser light onto a conveyed recording medium for exposure. , a control means for controlling each of the means, and a laser recording apparatus that scans the recording medium with a laser beam modulated by the modulation means to perform recording according to the image signal, wherein the control means comprises: A laser recording apparatus characterized in that, when not printing, the output of the laser generating means is controlled to be lower than that during printing, and the scanning speed of the scanning means is controlled to be lower than that during printing. 2. A laser recording apparatus according to claim 1, wherein the control means controls to set a longer exposure time in main scanning by the scanning means during non-printing. 3. A laser recording apparatus according to claim 1, wherein the control means includes a relay that is switched between printing and non-printing. 4. In the apparatus according to claim 1, the control means includes a laser light detection means for detecting the laser light generated from the laser generation means, and the output from the laser light detection means is transmitted to the laser light detection means. A laser recording device characterized in that the output of the laser generating means is maintained at a constant level by feeding back to a drive circuit of the laser generating means.