JPH0736599B2 - Exposure device for laser recording device - Google Patents

Description

Description: 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, and particularly to a speed of a scanning unit for scanning a laser beam on a recording medium. The present invention relates to an exposure device of a laser recording device that is adjustable.

2. Description of the Related Art As an exposure device for a laser printer, a rotary polygonal mirror (polygon mirror) formed by arranging a plurality of plane mirrors in a row on the peripheral surface of a rotating body
It is known that a laser beam is reflected by a laser beam so that the recording medium can be irradiated with the laser beam, and the polygon mirror is rotated by a scan motor to scan the laser beam.

In such an exposure apparatus, conventionally, the scan motor is driven to be turned on / off in accordance with the on / off state of the printer main power source. Therefore, there is a problem in that the scan motor is driven at a specified number of revolutions even when the actual printing is not performed, and thus the wind noise of the polygon mirror and the rotation noise of the scan motor are large. . In particular, when the print speed is medium or high speed (for example, 10000 rpm or more), there are drawbacks that the noise during standby is considerably large and the life of the scan motor is shortened.

In order to solve such a problem, there is a conventional one in which the scan motor is stopped during standby and the scan motor is driven by a print execution request signal. However, in such a configuration, it takes a long time for the number of rotations of the scan motor to stabilize at the specified number of rotations, so that there is a problem that the first print after the waiting is delayed. In particular, when the number of rotations of the scan motor is medium to high speed (10,000 rpm or more), the delay becomes large and the printing efficiency is deteriorated.

It is an object of the present invention to provide an exposure apparatus for a laser recording apparatus that solves the above-mentioned conventional drawbacks, reduces the noise of the scanning device in the standby mode, and can immediately perform the first printing. To do.

In order to achieve the above object, the present invention provides a laser generating means for generating a laser beam modulated according to recording data, and a laser beam generated by the laser generating means for scanning on a recording medium conveyed. In an exposure device of a laser recording apparatus having a scanning means for performing exposure and controlling the scanning means, the scanning means is driven at a speed lower than that at the time of recording when transfer of recording data is started. After the transfer of the print data, when the print request signal is generated, the scanning means is driven at a specified speed at the time of printing, and the control means controls the driving of the scanning means to stop after the printing is completed. Is characterized by.

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

FIG. 3 shows a schematic configuration diagram of a laser printer to which the present invention can be applied, and FIG. 4 shows a detailed view of an essential part of FIG. As shown in FIG. 3, the recording medium 2 conveyed in the direction of the arrow F by the conveyance motor is uniformly charged by corona discharge or the like by the charging unit 4, and then the laser modulated by the exposure unit 6 according to the image signal. It is exposed to the light 8 and developed with toner in the developing unit 10, the toner image is transferred to the recording paper 14 in the transfer unit 12, and then the charge removing unit 16 removes the charge by light or corona discharge of reverse polarity, and the cleaning. The area 18 is cleaned, and the charging section 4 is uniformly charged again.

As shown in FIG. 4, the exposure unit 6 includes a polygon mirror 22 as a scanning means for scanning the laser beam 8 and a scan motor 24 for rotationally driving the polygon mirror 22 in the direction of arrow G in the figure. Scanning device, an LD unit 26 as a laser light modulator, a beam compressor lens 28, a first cylindrical lens 30, and two fθ.
Lens 32, mirror 34, and second cylindrical lens 36
A synchronous mirror 38 and a synchronous sensor 40 including a light receiving element are attached to a housing 42. Then, the laser beam 8 emitted from the LD unit 26 after being modulated according to the image signal is transmitted through the aperture window 44, the beam compressor lens 28,
It is guided to the rotating polygon mirror 22 through the first cylindrical lens 30. The laser beam 8 reflected by the polygon mirror 22 has two fθ lenses 32, 32.
The laser beam 8 reflected by the mirror 34 passes through the slit 46 and is emitted downward from the lower surface of the housing 42 to form a second cylindrical lens.
The recording medium 2 is exposed through 36. Here, when the scan motor 24 is driven to rotate the polygon mirror 22, the laser beam 8 is repeatedly scanned within the range shown by the arrow H in the figure according to the rotational angle position. At one end of this scanning range, the laser light 8 is guided to the synchronous mirror 38,
The laser beam 8 reflected by 38 is detected by the synchronization sensor 40 through the opening window 48, and thereby the scanning synchronization is detected. The two fθ lenses 32,3
Reference numeral 2 is for adjusting the laser beam 8 reflected and scanned by the polygon mirror 22 so as to enter the mirror 34 at a right angle at any scanning position.

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

As shown in FIG. 2, the laser printer 100 is composed of a controller section 110 and a plotter section 120.
Recording data and control information from 200 are transferred and input to the controller unit 110. The controller unit 110 is formed by having a memory RAM, and the recording data to be transferred and input is temporarily stored in the RAM, and one section of recording data corresponding to a predetermined print amount (for example, one page) is prepared. Is detected and a print execution request signal is sent to the signal line 114.
And the data is converted into an image signal and then output to the plotter unit 120 via the signal line 112. Further, the controller unit 110 has a transfer start detecting means for detecting the start of accumulation depending on whether or not the record data is input in the RAM. This detection means outputs a transfer state signal which becomes H level to the plotter section 120 via the signal line 116 when the recording data is continuously input into the RAM.

As shown in FIG. 1, the plotter unit 120 includes an input / output unit I / O 122,
CPU124, RAM126, program memory 128, image signal control circuit
130 and a motor drive circuit 132 are formed. The motor drive circuit 132 includes a drive unit 134, a speed switching unit 136, a low speed rotation speed setting unit 138, and a specified rotation speed setting unit 140. The scan motor 24 is a servo motor based on a PLL (Phase Locked Loop), and each rotation speed setting unit 138, 140 is formed of a crystal oscillator that outputs a clock pulse having a frequency according to the rotation speed.

The low-speed rotation drive command or the specified rotation drive command is sent to the speed changer 136 from the CPU 124 via the I / O 122, respectively.
The speed changer 136 selects the setters 138 and 140 corresponding to the input drive command and outputs the output pulse to the drive unit 134.

The detailed configuration of the embodiment thus configured will be described together with the operation with reference to the operation waveform charts of the respective parts shown in FIGS. 5 (a) to 5 (d). First, at time t ₁ shown in FIG. 5, transfer of print data from the host machine 200 to the control unit 110 is started as shown in FIG.
If the transfer is completed at t ₂ , the control unit 110 outputs a transfer state signal that is at the H level while the transfer input continues, as shown in FIG. The CPU 124 detects the rising of the transfer state signal input via the I / O 122 to change to the H level, detects that the recording data has started to be accumulated, and outputs it via the signal line 142. Set the command to H level. As a result, the speed changer 136 is switched so as to connect the output of the low speed revolution setting device 138 to the drive unit 134, and the drive unit 134 is driven by the low speed revolution NL of the scan motor 24 as shown in FIG. 5 (d). Start driving.

Then, when the transfer input of the recording data is completed at t ₂ and the form feed of the control information is input from the host machine 200 at the subsequent t ₃ , the controller unit 11 sends the control information via the signal line 114 in FIG. The print execution request signal shown in () is output to the plotter unit 120. CPU 124 of plotter section 120
Resets the low-speed rotation drive command to the L level based on the input print execution request signal, and sets the specified rotation drive command output to the speed changer 136 via the signal line 144 to the H level. As a result, the speed changer 136 is switched to connect the output of the specified rotation speed setting device 140 to the drive unit 134, and the drive unit 134 lowers the rotation speed of the scan motor 24 as shown in FIG. 5 (d). Increase the speed from the speed NL to the specified speed NH.

In this way, when the scan motor 24 reaches the specified number of revolutions NH, the CPU 124 synchronizes with the rotation of the polygon mirror 22 rotated by the scan motor 24, and the control unit
The image data read from the RAM of 110 is fetched through the signal line 112 and output to the LD unit 26 through the image signal control circuit 130. As a result, the laser diode LD of the LD unit 26 is turned on / off by the image signal, the laser beam 8 modulated by the image signal and synchronized with the polygon mirror 22 is scanned on the recording body 2, and the recording body 2 is scanned. An electrostatic latent image corresponding to the recorded data is formed.

When all the recording data once stored in the RAM of the control unit 110 is read out, the CPU 124 detects it at t ₄ and resets the specified rotation drive command to the L level, and the scan motor 24 and the polygon mirror 22. Stops the rotation of and returns to the standby state.

Since the laser beam 8 does not need to be scanned during driving at the low speed rotation speed NL, it is desirable that the value NL is sufficiently low from the viewpoint of noise. From the point of shortening the time to reach several NH (that is, the delay time until the first print can be performed), the time required to change from NL to NH is 2-3.
It is desirable to set it to be about a second.

As described above, according to the present embodiment, the drive of the scan motor is started at a rotation speed lower than the specified rotation speed when the accumulation of the print data is started, and the specified rotation speed is issued when the print execution request is issued. The number of wind noises of the polygon mirror and the rotation noise of the scan motor during standby before the transfer of print data is increased because the number of prints is increased and the print data is stopped until the next print data starts to be stored. It is possible to remove the noise caused by the noise and reduce the noise during the transfer of the recording data.

Further, when the print execution request is issued, the scan motor is driven at the low rotation speed, so that the specified rotation speed can be reached quickly, and the first printing can be performed quickly.

For comparison, the drive pattern of the scan motor according to the conventional example described above is changed to the rotation speed pattern.
Shown in Figures (e) and (f). The figure (e) shows the case where the scan motor 24 is driven on and off in accordance with the on / off of the main power source of the laser printer, and the figure (f) shows the scan when the print execution request signal is input. The case where the driving of the motor 24 is started is shown. In the conventional example of (e), since the scan motor constantly rotates at the specified rotation speed, noise is large and the life of the scan motor is short. As can be seen from the figure, the conventional example of (f) has a shorter noise generation time during standby than the present embodiment, but until the number of rotations of the scan motor reaches a specified value after the print execution request signal is input. There is a delay time T _0, which delays the first print and the end of the print.

The motor drive circuit 132 of the embodiment shown in FIG. 1 may be replaced with the structure shown in FIG. That is, as shown in FIGS. 6 and 7, the reference clock pulse output from the oscillator 146 is divided into a low speed rotation speed NL and a specified rotation speed NH by a frequency divider 148 formed by applying a binary counter or the like. Pulses of two frequencies corresponding to each other are formed, and a pulse switch of the AND circuits 150, 152 and the OR circuit 154 drives the pulses of the frequencies corresponding to the low speed rotation drive command and the specified rotation drive command input from the signal lines 142, 144. The data is output to the unit 134.

As described above, according to the present invention, the driving of the scanning unit is stopped while the transfer of the print data is not started in the standby state, and the scanning unit is stopped when the data transfer is started. Driving is started at a lower speed than that, and when a print execution request for actual printing is issued, the scanning means is accelerated to a prescribed speed.
There is an effect that the noise generation time during standby is shortened, the noise level is reduced, and the noise is reduced as a whole. Further, since the scanning means is driven at a high speed for a short time, the life of the scanning means is extended. Further, since the scanning means is driven at a low speed in advance before the printing is executed, the specified speed is quickly reached when the printing is executed, so that there is an effect that the first printing can be performed immediately.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram of an embodiment to which the present invention is applied,
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 a main part of FIG. FIG. 5 is an operation waveform diagram of each part of FIG. 1 embodiment, FIG. 6 is a partial configuration diagram of one embodiment to which the present invention is applied, and FIG. 7 is an operation waveform diagram of each part of FIG. 6 embodiment. Is. Explanation of symbols of main parts 2 …… Recording medium 6 …… Exposure section 8 …… Laser light 22 …… Polygon mirror 24 …… Scan motor 26 …… LD unit 100 …… Laser printer 110 …… Controller section 120 …… Plotter Part 132: Motor drive circuit.

Front page continuation (72) Inventor Koji Nishitoku 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) Reference JP-A-56-22415 (JP, A)

Claims (1)

[Claims] 1. A laser generating means for generating a laser beam modulated according to recording data, and a scanning means for scanning a laser beam generated by the laser generating means on a conveyed recording medium for exposure. In the exposure apparatus of the laser recording apparatus having a control unit for controlling the scanning unit, the control unit is configured to, when transfer of recording data is started,
The scanning means is driven at a speed lower than that at the time of recording, and when the recording request signal is generated after the transfer of the recording data, the scanning means is driven at a specified speed at the time of recording, and after the recording is completed, the scanning means is driven. An exposure apparatus for a laser recording apparatus, which is controlled so as to stop.