JPS6282877A - Exposing device for laser recording device - Google Patents

Abstract

PURPOSE:To reduce noise at the time of waiting and to execute immediately an initial printing by driving a scanning means at low speed at the start of transfer of recording data, increasing the driving speed to regular speed at the time of printing and stopping the drive at the end of printing. CONSTITUTION:A CPU 124 detects the leading edge of the change of a transfer status signal inputted through an I/O 122 to the 'H' level to detect the start of accumulation of recording data and sets up a low speed rotatinal driving command outputted through a signal line 142 to the 'H' level. Consequently, a motor driving circuit 132 drives a scanning motor 24 at a low rotational frequency NL. When a print execution request signal is inputted after the completion of a transfer input, the CPU 124 resets the low rotational driving command to the 'L' level and sets up a regulated rotational driving command outputted through a signal line 144 to the 'H' level. Consequently, the circuit 132 increases the rotational speed of the motor 24 up to the regulated rotational frequency NH. After the end of printing, the CPU 124 detects the end and resets the regulated rotational driving command to the 'L' level to stop the rotation of the motor 24 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of the Invention 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, and particularly to a scanning means for scanning a recording medium with laser light. The present invention relates to an exposure device for a laser recording device whose speed can be adjusted.

Conventional technology A rotating polygon mirror (polygon mirror) is used as an exposure device for a laser printer, and is made up of a plurality of plane mirrors arranged around the circumference of a rotating body.
It is known that a polygon mirror is formed so as to be able to reflect a laser beam and irradiate it onto a recording medium, and the polygon mirror is rotated by a scan motor to scan the laser beam.

Conventionally, in such an exposure apparatus, the scan motor is turned on and off in accordance with the on and off of the printer's main power supply. Therefore, even during standby when actual printing is not being performed, the scan motor is driven at a specified rotation speed, which causes problems such as large noises such as polygon mirror wind noise and scan motor rotation noise. . Particularly, when the printing speed is medium or high (for example, 110,000 rpm or more), the noise during standby is quite large, and the life of the scan motor is shortened.

In order to solve this problem, there has conventionally been a system in which the scan motor is stopped during standby and is driven by a print execution request signal. However, with such a printer, it takes a long time for the rotational speed of the scan motor to stabilize at a specified rotational speed, so there is a problem that the first printing after waiting is delayed. Especially when the scan motor rotation speed is medium or
In the case of high speed (10,000 rpm or more), the delay becomes large and printing efficiency deteriorates.

Purpose The present invention aims to eliminate such conventional drawbacks, reduce the noise of the scanning device during standby, and provide an exposure device for a laser recording device that can immediately perform the first print. do.

(2) In order to achieve the above object, the present invention includes a laser generating means for generating a laser beam modulated according to recording data, and a laser beam generated from the laser generating means on a recording medium being conveyed. In an exposure device of a laser recording apparatus that includes a scanning means for scanning and exposing, and a control means for controlling the scanning means, when the transfer of recording data is started, the scanning means is operated at a speed lower than that during recording. After the recording data is transferred, the scanning means is driven at a prescribed speed for recording when a recording request signal is generated, and the control means controls the scanning means so that the driving of the scanning means is stopped after recording is completed. It is characterized by

Hereinafter, the present invention will be explained based on examples.

FIG. 3 shows a schematic configuration diagram of a laser printer to which the present invention is applicable, and FIG. 4 shows a detailed view of the main parts of FIG. 3. As shown in FIG. 3, the recording medium 2 conveyed in the direction of arrow F by a conveyance motor is uniformly charged by corona discharge or the like in a charging section 4, and then is exposed to a laser beam modulated in accordance with an image signal in an exposure section 6. The toner image is exposed to light 8, developed with toner in a developing section 10, and transferred to a recording plate 14 in a transfer section 12,
Thereafter, the static electricity is removed by light or corona discharge of opposite polarity in the static eliminating part 16, and the cleaning part 18 cleans it.
It is uniformly charged again by the charging section 4.

As shown in FIG. 4, the exposure section 6 includes a polygon mirror 22 as a scanning means for scanning the laser beam 8, and a scan motor 24 that rotates the polygon mirror 22 in the direction of arrow G in the figure. an LD unit 26 as a laser beam modulation means, a beam compressor lens 28, and a first cylindrical lens 30.
It is formed by attaching to a housing 42 two fθ lenses 32, a mirror 34, a second cylindrical lens 36, a synchronization mirror 38, and a synchronization sensor 40 consisting of a light receiving element. The laser beam 8 modulated according to the image signal and emitted from the LD unit 26 is transmitted through the aperture window 44. Beam compressor lens 28. The light is guided through the first cylindrical lens 30 to the rotating polygon mirror 22. The laser beam 8 reflected by this polygon mirror 22 passes through two fθ lenses 32 and 32.
The laser beam 8 that is reflected by the mirror 34 is emitted downward from the lower surface of the housing 42 via the Surin I 46, passes through the second cylindrical lens 36, and is directed onto the recording medium 2. exposed to light. When the scan motor 24 is driven to rotate the polygon mirror 22, the laser beam 8 is scanned back to the range indicated by the arrow H in the figure in accordance with the rotational angular position. At one end of this scanning range, the laser beam 8 is guided to a synchronous mirror 38, and the laser beam 8 reflected by the synchronous mirror 38 is detected by the synchronous sensor 40 through an aperture window 48.
This allows the scanning period to be detected. Note that the two fθ lenses 32°32 are polygon mirrors 22.
The laser beam 8 reflected and scanned by the mirror 3 is adjusted so that it is incident at right angles to the mirror 3 =1 at any scanning position.

FIG. 1 shows a block diagram of the main parts of an embodiment to which the present invention is applied, and FIG. 2 shows an overall block diagram.

As shown in FIG. 2, the laser printer 100 includes a controller section 110 and a plotter section 120, and recording data and control information are transferred and input from the host machine 200 to the controller section 110. The controller unit 110 is formed with a memory RAM, and temporarily stores recorded data to be transferred and input in the RAM, and stores one section of recorded data corresponding to a predetermined print amount (for example, one page). When it is detected that all of the data is complete, a print execution request signal is outputted to the block section 120 via the signal line 114, and the data is converted into an image signal and then via the signal line 112. Further, the controller section 110 has a transfer start detection means for detecting that storage has started based on whether recording data is input into the RAM. This detection means is the RAM
When the input of recording data is 4ak within the range of 4k, a transfer status signal of level 5 is output to the plotter section 120 via the signal line 116.

As shown in FIG. 1, the plotter section 120 has an input/output section l1.
0122. CPU124. It is formed to include a RAM 126° program memory 1281, an image signal control circuit 130°, and a motor drive circuit 132.

The motor drive circuit 132 includes a drive section 134 and a speed switch 1.
36, a low speed rotation speed setting device 138, and a specified rotation speed setting device 140. The scan motor 24 is a PLL (phase locked loop) servo motor, and each rotation speed setter 138, 140 is formed from a crystal oscillator that outputs a clock pulse with a frequency corresponding to the rotation speed.

The speed switch 136 is connected to the CPU 12 via l10122.
From 4, the low-speed rotation drive command or the specified rotation drive command is
They are input through signal lines 142 and 144, respectively.
The speed switch 136 selects the setter 138, 140 corresponding to the manually inputted drive command, and outputs the output pulse to the drive unit 134.

The detailed configuration of the embodiment configured as described above is shown in FIG.
) to (d) while referring to the operation waveform diagrams of each part.
This will be explained along with the operation. First, at time t1 shown in FIG. 5, the transfer of recording data from the host machine 200 to the control section 110 is started as shown in FIG. 110 outputs a transfer status signal that is at H level during the period when the transfer input continues, as shown in FIG. 1(c). The CPU 124 detects the rise of the transfer status signal inputted through the l10122 to change to H level, detects that storage of recording data has started, and issues a low-speed rotation drive command to be outputted through the signal line 142. Set to H level. As a result, the speed switch 136 is switched to connect the output of the low speed rotation speed setting device 138 to the drive section 134, and the drive section 134 controls the scan motor 24 by the low speed rotation speed NL as shown in FIG. 5(d). Start driving.

Then, when the transfer input of recording data is completed at time t2, and the form feed of control information is input from the host machine 200 at time <t3, the controller unit 11
0 outputs a print execution request signal shown in FIG. 5(a) to the plotter section 120 via the signal line 114. The CPU 124 of the block unit 120 resets the low-speed rotation drive command to the L level based on the print execution request signal input manually, and also sets the specified rotation drive command output to the speed switch 136 via the signal line 144 to the H level. Set to . As a result, the speed switch 136 is switched to connect the output of the specified rotation speed setting device 140 to the drive section 134, and the drive section 134 changes the rotation speed of the scan motor 24 to a low speed as shown in FIG. 5(d). The speed is increased from the rotation speed NL to the specified rotation speed NH.

In this way, the scan motor 24 is rotated at the specified rotation speed N.
When reaching H, the CPU 24 takes in the image data read out from the RAM of the control unit 110 via the signal line 112 in synchronization with the rotation of the polygon mirror 22 rotated by the scan motor 24, and controls the image signal control circuit 130. The signal is output to the LD unit 26 via the LD unit 26. As a result, the laser diode LD of the LD unit 26 is turned on and off by the image signal, and the laser beam 8 modulated by the image signal and synchronized with the polygon mirror 22 is scanned onto the recording medium 2. An electrostatic latent image is formed according to the recorded data.

Then, once all the recorded data once stored in the RAM of the control unit 110 has been read out, the CPU 124 detects this at time t4 and resets the specified rotation drive command to the L level, and controls the scan motor 24 and polygon mirror 22. Stops rotation and returns to standby state.

Note that it is not necessary to scan the laser beam 8 while driving at the low rotational speed NL, so it is desirable that the value NL is sufficiently low from the viewpoint of noise. From the point of view of shortening the time required to reach several NH (that is, the delay time until the first print can be performed), it is recommended to set the time required to reach NL-NH to be about 2 to 3 seconds. is desirable.

As described above, according to this embodiment, the scanning motor is started to be driven at a rotation speed lower than the specified rotation speed when storage of recording data is started, and when a print execution request is issued, the scan motor is driven at a rotation speed lower than the specified rotation speed. Polygon Mirror 〇 Wind noise and scan motor rotation noise are reduced during standby before transferring recorded data. This has the effect that it is possible to eliminate the noise caused by the transfer of recorded data and to reduce the noise during the transfer of recorded data.

Furthermore, since the scan motor is being driven at a low rotational speed at the time when a print execution request is issued, the scan motor quickly reaches the specified rotational speed and the first print can be performed quickly.

Incidentally, for comparison, the drive pattern of the scan motor according to the conventional example described above was changed to the rotational speed pattern, and the fifth
Shown in Figures (e) and (f). The figure (e) shows the case where the scan motor 24 is turned on and off in accordance with the on/off of the main power supply of the laser printer, and the figure (f) shows the case where the scan motor 24 is driven on and off when the main power supply of the laser printer is turned on and off, and the figure (f) shows the case where the scan motor 24 is driven when the print execution request signal is input. motor 24
This shows the case where the drive starts. In the conventional example (e), the scan motor always rotates at a specified rotational speed, resulting in large noise and short life of the scan motor. (f)
As can be seen from the figure, in the conventional example, the noise generation time during standby is shorter than in this embodiment, but there is a delay time after the print execution request signal is input until the rotation speed of the scan motor reaches the specified value. T. This causes a delay in the first print and a delay in the end of the print.

Note that in place of the motor drive circuit 132 of the embodiment in FIG.
It is also possible to adopt the configuration shown in FIG. That is, as shown in FIGS. 6 and 7, the reference clock pulse output from the oscillator 146 is divided into low rotational speeds NL by a frequency divider 148 using a binary counter or the like.
It forms pulses with two frequencies corresponding to the specified rotational speed NH, and connects them to the signal line 142°144 by a switch consisting of an AND circuit 152 and an OR circuit 154.
The drive unit 134 outputs pulses of frequencies corresponding to the low-speed rotation drive command and the specified rotation drive command input from the drive unit 134.

Effects As explained above, according to the present invention, the driving of the scanning means is stopped while the transfer of recording data has not started during standby, and when the transfer of data has started, the driving of the scanning means is stopped from the time of recording. The scanning means starts driving at a low speed, and when a print execution request for actual printing is issued, the speed of the scanning means is increased to a specified speed.
This has the effect that the noise generation time during standby is shortened, the noise level is reduced, and the noise is reduced overall. Furthermore, since the time during which the scanning means is driven at high speed is short, the life of the scanning means is also extended. Furthermore, since the scanning means is driven at a low speed before printing, it quickly reaches the specified speed when printing is performed, so that the first printing can be performed immediately.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the main parts of an embodiment to which the present invention is applied;
FIG. 2 is an overall configuration diagram of an embodiment to which the present invention is applied, FIG. 3 is a schematic configuration diagram of a laser printer to which the present invention is applicable, and FIG. 4 is a detailed configuration diagram of main parts of FIG. 5 is an operating waveform diagram of each part of the embodiment in FIG. 1, FIG. 6 is a partial configuration diagram of an embodiment to which the present invention is applied, and FIG. 7 is an operating waveform diagram of each part of the embodiment in FIG. 6. It is. Explanation of symbols of main parts 2...recording body 6...exposure section 8...laser beam 22...polygon mirror 24...scan morph 26...LD unit 100...laser printer 110... ...Controller section 120...Plotter section 132...Motor drive circuit.

Claims (1)

[Claims] 1. Laser generating means for generating a laser beam modulated according to recording data; and scanning and exposing the conveyed recording body with the laser beam generated from the laser generating means. In an exposure device of a laser recording apparatus having a scanning means and a control means for controlling the scanning means, when transfer of recording data is started, the scanning means is driven at a lower speed than during recording, and the recording data is After the transfer, the scanning means is driven at a specified speed for recording when a recording request signal is generated, and the control means controls the scanning means so that the driving of the scanning means is stopped after recording is completed. Exposure device of recording device. 2. An exposure device for a laser recording apparatus according to claim 1, wherein the scanning means comprises a polygon mirror and a scan motor for driving the polygon mirror. 3. The apparatus according to claim 1, wherein the scanning means includes an oscillator that generates pulses of a constant frequency;
A frequency divider that divides the pulses generated from the oscillator to generate pulses with a specified speed frequency and a pulse with a low speed frequency, and selects one of two types of pulses from the frequency divider. 1. An exposure device for a laser recording device, comprising a selection circuit.