JPH05333280A - Laser beam recorder - Google Patents

Abstract

PURPOSE:To obtain a laser beam recorder whose cost is low and in which a, polygon mirror is stably rotated with a simple system by utilizing a main scanning starting signal required for laser recording and comparing it with a referential clock signal without especially using an encoder. CONSTITUTION:The recorder is provided with a clock generating circuit 10 generating the referential clock signal (PLCLK) which is the reference or the revolving speed or the polygon mirror 1, a light receiving circuit 4 receiving light reflected from the polygon mirror 1 in the middle of rotating, and generating a main scanning starting referential signal (LSYNC) which is the reference of a main scanning starting time at a fixed specified position, and a PLL(Phase Locked Loop) circuit 8 driving a motor driving circuit 7 so that the phase of the referential clock signal may be aligned with that of the main scanning starting referential signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam recording device, for example, a laser beam recording device mounted on a facsimile or a printer.

[0002]

2. Description of the Related Art As a conventional laser beam recording apparatus, one using a polygon mirror is known. In such a laser beam recording apparatus, the rotation of the polygon mirror is made constant and stable as follows. That is, the output of an encoder that detects the rotation speed (such as one that detects light, one that detects coil current, one that detects a magnetic field) is compared with the reference clock signal, and the polygon mirror is driven so that they match. The drive current of the motor is controlled. The control circuit and driver may be built in the motor or installed externally. For example, the one disclosed in Japanese Patent Laid-Open No. 2-89469 compares a signal detected by a photo interrupter of an optical encoder attached to a motor with a reference clock signal to stabilize the rotation of a polygon mirror. ing.

[0003]

However, in such a conventional laser beam recording apparatus, there is a problem that the cost increases because an expensive encoder is used. Therefore, the present invention makes it possible to stably rotate the polygon mirror with a simple system by comparing the reference scanning clock signal with the main scanning start signal required for laser recording without using an encoder. An object of the present invention is to provide a cost-effective laser beam recording apparatus.

The one disclosed in Japanese Patent Laid-Open No. 3-54512 has a plurality of main scanning start signals,
A pixel transfer clock is generated from this, but it is not used for rotation control of the polygon mirror.

[0005]

The invention according to claim 1 is
In order to solve the above problems, in a laser beam recording apparatus which has a motor drive circuit for driving a motor connected to a polygon mirror and scans a rotating polygon mirror by reflecting a laser beam, the number of rotations of the polygon mirror. A clock generation circuit that generates a reference clock signal that serves as a reference, and a main scanning start reference signal that serves as a reference for the main scanning start time by receiving light reflected from a rotating polygon mirror at a fixed predetermined position. And a PLL for driving the motor drive circuit so that the phase of the main scanning start reference signal matches the phase of the reference clock signal.
(Phase Locked Loop) circuit is provided.

In order to solve the above-mentioned problems, the invention according to claim 2 is provided with a control means for controlling the recording operation in addition to the structure of claim 1, and the control means changes the rotation speed from the start of rotation of the polygon mirror. Set the minimum time to stabilize beforehand,
It is characterized in that the laser beam is continuously turned on before the minimum time elapses, and then the laser beam is turned off at the time point when the PLL circuit is locked to make the writable state.

In order to solve the above problems, the invention according to claim 3 is, in addition to the structure of claim 1, connected to an external device, a control means for controlling the recording operation, a display means for displaying predetermined information. When the PLL loop is disconnected during writing and recording, the control means immediately turns off the laser beam to stop the recording operation, and discharges the recording paper in the machine and the photosensitive member. It is characterized in that the charge-eliminating cleaning operation is executed and the recording unit abnormality is displayed on the display means and declared to the external interface.

In order to solve the above-mentioned problems, the present invention according to claim 4 further comprises a control means for controlling the recording operation in addition to the structure according to claim 1, wherein the control is performed when the PLL loop is deviated during the non-recording operation. The means is characterized in that all the laser beams are directly turned on, and when the PLL circuit is stably locked, the laser beam is turned off and returned to the original state.

In order to solve the above-mentioned problems, the invention according to claim 5 is, in addition to the configuration of claim 2 or claim 4, a display means for displaying predetermined information, and an external interface connected to an external device. If the PLL circuit is not stably locked within a predetermined time, the control means immediately turns off the laser beam, stops the motor driving the polygon mirror, and causes the display means to display an abnormality of the recording unit. It is characterized by declaring to external interface.

In order to solve the above-mentioned problems, the invention according to claim 6 provides a control means when a nonvolatile storage means is provided in addition to the configuration of claim 4 and the PLL loop is released within a predetermined time after the loop is removed. However, it is characterized in that this return is detected and stored in the storage means every time. In order to solve the above-mentioned problems, an invention according to claim 7 is provided with an operation means for inputting an operation command and a display means for displaying predetermined information, in addition to the configuration of claim 6, and the control means comprises: It is characterized in that the stored contents of the storage means are displayed on the display means in response to an operation command from the operation means.

In order to solve the above-mentioned problems, the present invention according to claim 8 provides, in addition to the configuration of claim 6, a display means for displaying predetermined information and an external interface connected to an external device, and stores the information. When the number of detections stored in the means exceeds a preset number, the control means prohibits the recording operation, causes the display means to display an abnormality in the recording portion, and declares it to the external interface. There is.

In order to solve the above-mentioned problems, the invention according to claim 9 is provided with a display means for displaying predetermined information and an external interface connected to an external device, in addition to the structure according to claim 6, In response to a command from the interface, the control means reads out the stored content of the storage means, displays it on the display means, and prohibits the recording operation.

[0013]

According to the first aspect of the invention, the PLL circuit drives the motor drive circuit of the polygon mirror so that the phase of the main scanning start reference signal matches the phase of the reference clock signal. According to the invention of claim 2, in addition to the operation of claim 1, the minimum time from the start of rotation of the polygon mirror to the stable rotation speed is preset, and the laser beam is continuously turned on before the minimum time elapses. Then, next, when the PLL circuit is locked, the laser beam is turned off to enable the writing.

According to the third aspect of the invention, in addition to the function of the first aspect, when the PLL loop is released during writing and recording,
The laser beam is immediately turned off, the recording operation is stopped, the recording paper in the machine is discharged, and the photoconductor cleaning operation is performed.At the same time, the recording unit error is displayed on the display means and declared to the external interface. To be done. According to the invention of claim 4, in addition to the operation of claim 1, when the PLL loop is disengaged during the non-recording operation, all the laser beams are directly turned on and the laser beam is locked when the PLL circuit is stably locked. Turns off and returns to the original state.

According to the invention of claim 5, in addition to the operation of claim 2 or claim 4, when the PLL circuit does not stably lock within a predetermined time, the laser beam is immediately turned off and the polygon mirror is driven. The motor stops and the recording unit abnormality is displayed on the display means and declared to the external interface. According to the invention of claim 6, claim 4
In addition to the above function, when the PLL loop is released and then returned within a predetermined time, the return is detected and stored in the storage means every time.

According to the invention of claim 7, in addition to the operation of claim 6, the stored contents of the storage means are displayed on the display means in response to an operation command from the operation means. According to the invention of claim 8, in addition to the operation of claim 6, when the number of times of detection stored in the storage means exceeds a preset number, the recording operation is prohibited and the recording portion abnormality is displayed on the display means. And declared for the external interface.

According to the invention of claim 9, in addition to the operation of claim 6, the stored contents of the storage means are read out and displayed on the display means in response to a command from the external interface, and the recording operation is prohibited. To be done.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of a laser beam recording apparatus according to the present invention. First, the configuration will be described. In FIG. 1, a DC motor 2 rotates a polygon mirror 1. L
D (laser diode) 3 emits light, and polygon mirror 1
And is subjected to trajectory correction by the fθ lens 5 to scan the photoconductor 6. During the scanning process, the light receiving unit 4 is fixed at a predetermined position in the optical path in front of the image area. The light received by the light receiving unit 4 is input to the light receiving circuit 11 via an optical fiber, and is shaped there to generate a main scanning start reference signal (LSYNC) that serves as a reference for the main scanning start timing. LSYNC is
It is input to the recording image information control circuit 12 and the PLL circuit 8.

The reference clock signal (PLCLK) is CP
It is set by the control of a U (Central Processing Unit) 13 and generated by the clock generation circuit 10. This PLCLK is a reference clock signal that serves as a reference for the rotation speed of the polygon mirror, and is a signal generated by multiplying the required rotation speed of the polygon mirror 1 by the number of polygon surfaces. The PLL circuit 8 uses a DC motor driver (motor drive circuit) 7 so that the reference clock signal (PLCLK) and LSYNC have the same phase.
Drive current is controlled. The structure of the PLL circuit 8 may be a general one, and the PLL circuit 8 is L with respect to PLCLK.
If the SYNC is delayed, the drive current is increased, and if it is early, the control is performed in the opposite way, and the state is controlled by the CPU at a consistent and stable position.
Inform 13

The recording image information control circuit 12 adds image information to the pixel transfer clock (WCLK) generated by the clock generation circuit 10 and sends it to the LD driver 9 to drive the LD 3, and controls the LD emission amount and the image area. Control the light emission in other than. DC motor driver 7 and LD driver 9
Are DC motor 2 and LD 3 respectively due to noise.
It may be installed near the. The same applies to the PLL circuit 8. PLCLK and WCLK are set in correlation with each other according to the pixel density, and this is based on an instruction from the CPU 13.

Next, the operation will be described with reference to the timing chart of FIG. Turn on DC motor 2 from CPU13
When a command to perform is issued, the PLL circuit 8 is not yet locked, so that the DC motor driver 7 applies a current to the DC motor 2 and the motor 2 starts to rotate. Further, when the CPU 13 commands the recording image information control circuit 12 to turn on all the LDs 3,
D3 produces a specified amount of light.

Since the DC motor 2 does not have a sufficient rotation speed at this point, LSYNC has a cycle longer than that of the reference clock PLCLK as shown in FIG. The PLL circuit 8 is further controlled so that a current flows through the DC motor driver 7, and locked at the point A (FIG. 2). As described above, in the present embodiment, without using a conventional encoder,
By using the main scanning start signal (LSYNC) necessary for laser recording and comparing it with the reference clock signal (PLCLK), the polygon mirror 1 can be stably rotated by a simple system, so that the cost can be reduced. it can.

The main scanning start signal is a condition signal necessary for transferring the image information to the laser diode, and the reference clock signal for rotating the polygon mirror has a correlation with the pixel transfer clock. For this reason, in the present embodiment, the system control unit 18 constitutes the PLL circuit 8, so that the harness or the like can be simplified. An embodiment of the laser beam recording apparatus according to the invention of claim 2 is shown in FIGS.
Will be described based on the embodiment shown in FIG.

The CPU 13 of FIG. 1 constitutes a control means for controlling the recording operation, presets a minimum time from the start of rotation of the polygon mirror 1 until the number of rotations stabilizes, and sets the laser before the minimum time elapses. Turn on the beam continuously, then
When the PLL circuit 8 is locked, the recording image information control circuit is configured so that the laser beam is turned off and the writable state is set.
Control 12 In this way, the LD3 is turned on.
This is because the instruction must be output before the predicted point A in FIG. When the rotation of the DC motor 2 becomes stable at the point A, the LD 3 does not need to be continuously lit, and the LS
LD3 is turned off at the same time when the YNC pulse is detected, passes through the image area, and LD3 is turned on again before the next occurrence of LSYNC is predicted. In this state, the recording optical system becomes writable. The recording is performed by the recording image information control circuit 12 placing the image information in the image area in synchronization with WCLK as shown in FIG.

In the present embodiment, in addition to the effect of the embodiment of the invention described in claim 1, it is possible to provide appropriate turn-on timing and turn-off timing of the laser beam. An embodiment of the laser beam recording apparatus according to the invention of claim 3 will be described based on the embodiment shown in FIGS. 1 and 2. CPU13 of FIG.
Is a control unit for controlling the recording operation, and includes an operation display unit.
Reference numeral 15 constitutes display means for displaying predetermined information. The external interface (I / F) 16 is connected to the external device 17. The external device 17 is a partner facsimile machine through an exchange when the apparatus is a facsimile machine, and is a host machine when the apparatus is a printer. When the PLL loop comes off during writing and recording (this is DC
It is due to the abnormality of the motor 2 or the abnormality in the light emission of the LD 3), and when this is detected, the laser beam is immediately turned off to stop the recording operation (precharge, development, transfer operation),
While recording paper in the machine is discharged and the photoconductor is cleaned by static electricity, the operation display unit 15
, And declare it to the external I / F 16.

In addition to the effect of the embodiment of the invention described in claim 1, this embodiment can provide an appropriate coping method when the PLL loop is deviated during writing and recording. An embodiment of the laser beam recording apparatus according to the invention of claim 4 will be described based on the embodiment shown in FIGS. 1 and 2. C
The PU 13 constitutes a control means for controlling the recording operation, and repeats the operation of FIG. 2 from the beginning when the LSYNC is out of synchronization during standby, and continues the normal operation when stable recovery is achieved within a predetermined time. That is, if the PLL loop is broken during the non-recording operation, the CPU 13 immediately turns on all the laser beams, and when the PLL circuit 8 is stably locked, the CPU 13 turns off the laser beams to restore the original state.

In this embodiment, in addition to the effect of the embodiment of the invention described in claim 1, it is possible to provide an appropriate method for coping with the case where the PLL loop is disconnected during standby. An embodiment of the laser beam recording apparatus according to the invention of claim 5 will be described based on the embodiments of the inventions of claims 2 and 4. The operation display unit 15 of FIG. 1 constitutes display means for displaying predetermined information, and the external I / F 16 is connected to the external device 17. When the PLL circuit 8 does not stably lock within a predetermined time, the CPU 13 immediately turns off the laser beam, stops the motor 2 that drives the polygon mirror 1, and causes the operation display unit 15 to display a recording unit abnormality. External I
/ F16 is declared.

In this embodiment, in addition to the effects of the embodiments of the present invention described in claims 2 and 4, it is possible to provide a method of coping with the case where the PLL circuit 8 does not lock stably within a predetermined time. On the other hand, as described in the embodiment of the laser beam recording apparatus according to the fourth aspect of the invention, the frequent occurrence of the PLL loop being released during the standby indicates that the system has an abnormality. .. The inventions according to claims 6 to 9 described below deal with this abnormality.

An embodiment of the laser beam recording apparatus according to the invention of claim 6 will be described based on an embodiment of the invention of claim 4. The non-volatile memory 14 constitutes a storage means, and as such a memory, for example, an EEPROM (Electr
ically erasable and Programable Read Only Memory)
Or battery-backed RAM (Randam Access Me
mory) etc. When the PLL loop recovers within a predetermined time after the loop is removed, the CPU 13 detects this recovery and stores it in the memory 14 so that the memory 14 can count the number of times.

An embodiment of the laser beam recording apparatus according to the invention of claim 7 will be described based on an embodiment of the invention of claim 6. The operation display unit 15 of FIG. 1 also serves as an operation unit for inputting an operation command and a display unit for displaying predetermined information. The memory 14 stores the number of times of occurrence of abnormality as in the above-described embodiment, and also stores other abnormality such as paper conveyance abnormality and I / O.
It stores F fail and the like. The CPU 13 can display the number of occurrences of abnormalities and other abnormal phenomena stored in the memory 14 on the operation display unit 15 in response to an operation command from the operation display unit 15, or can notify the outside through the external I / F 16. ..

An embodiment of the laser beam recording apparatus according to the invention of claim 8 will be described based on an embodiment of the invention of claim 6. The operation display unit 15 of FIG. 1 constitutes a display means for displaying predetermined information. The CPU 13 constantly scans the number of occurrences of abnormality stored in the memory 14, and when the number of occurrences exceeds a preset number, the recording operation is prohibited, and the abnormality of the recording unit is displayed on the operation display unit 15 so that the external I / F16 is declared.

An embodiment of the laser beam recording apparatus according to the invention of claim 9 will be described based on an embodiment of the invention of claim 6. An external host or a terminal through a line can send a command for outputting the contents of the memory 14 to the CPU 13 through the external I / F 16 and read the output contents. In addition, similarly, it is possible to send a command to prohibit and display the recording unit operation to the CPU 13 through the external I / F 16 by external judgment. The same applies to other abnormal phenomena stored in the memory 14. That is, the CPU 13 uses the external I / F
In response to a command from 16, the stored contents of the memory 14 are read out and displayed on the operation display unit 15, and the recording operation is prohibited.

[0033]

According to the present invention, a PLL circuit is provided,
Since the rotation of the polygon mirror is controlled by comparing the main scanning start signal required for laser recording and the reference clock signal,
The polygon mirror can be stably rotated by a simple system, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram including a control block configuration showing an embodiment of a laser beam recording apparatus according to the present invention.

FIG. 2 is a timing chart for explaining the operation of the device shown in FIG.

[Explanation of symbols]

 1 polygon mirror 2 DC motor (motor) 3 laser diode 4 light receiving circuit 6 photoconductor 7 DC motor driver (motor drive circuit) 8 PLL circuit 10 clock generation circuit 13 CPU (control means) 15 operation display section (operation means, display means) 14 Memory (nonvolatile storage means) 16 External I / F (external interface)

Claims (9)

[Claims] 1. A laser beam recording apparatus having a motor drive circuit for driving a motor connected to a polygon mirror, wherein a rotating polygon mirror reflects a laser beam to scan the polygon mirror. A clock generation circuit that generates a reference clock signal and a light reception that receives the light reflected from the rotating polygon mirror at a fixed fixed position and generates a main scan start reference signal that serves as a reference for the main scan start timing. Circuit and the PL that drives the motor drive circuit so that the phase of the main scanning start reference signal matches the phase of the reference clock signal.
A laser beam recording device comprising an L (Phase Locked Loop) circuit. 2. A control means for controlling a recording operation is provided, wherein the control means presets a minimum time from the start of rotation of the polygon mirror until the number of rotations stabilizes, and the laser beam before the minimum time elapses. Lights continuously, then PL
2. The laser beam recording apparatus according to claim 1, wherein the laser beam is turned off to make a writable state when the L circuit is locked. 3. A control means for controlling a recording operation, a display means for displaying predetermined information, and an external interface connected to an external device are provided, and when the PLL loop is disconnected during writing and recording, the control is performed. Means to immediately turn off the laser beam to stop the recording operation, to discharge the recording paper in the machine and to perform the charge removal cleaning operation on the photoconductor, and at the same time, to display the recording section abnormality on the display means and to the external interface. The laser beam recording device according to claim 1, wherein the laser beam recording device is declared. 4. A control means for controlling a recording operation is provided, and when the PLL loop is disengaged during a non-recording operation, the control means directly turns on all the laser beams, and the PLL circuit is stably locked. 2. The laser beam recording apparatus according to claim 1, wherein the laser beam is turned off at the time point to restore the original state. 5. When a display means for displaying predetermined information and an external interface connected to an external device are provided and the PLL circuit does not stably lock within a predetermined time,
3. The control unit immediately turns off the laser beam, stops the motor driving the polygon mirror, displays the recording unit abnormality on the display unit, and declares it to the external interface. Item 4
The laser beam recording apparatus described. 6. A non-volatile storage means is provided, and when the PLL loop is restored within a predetermined time after the loop is removed, the control means detects this return and stores it in the storage means every time. 4. The laser beam recording device according to 4. 7. An operation means for inputting an operation command and a display means for displaying predetermined information are provided, and the control means displays the stored contents of the storage means on the display means in accordance with the operation command from the operation means. The laser beam recording apparatus according to claim 6, wherein the laser beam recording apparatus displays the information. 8. A control means provided with a display means for displaying predetermined information and an external interface connected to an external device, wherein when the number of detection times stored in the storage means exceeds a preset number, the control is performed. Means prohibits the recording operation,
7. The laser beam recording apparatus according to claim 6, wherein an abnormality of the recording unit is displayed on the display means and declared to the external interface. 9. A display means for displaying predetermined information and an external interface connected to an external device are provided, and the control means reads the stored contents of the storage means in response to a command from the external interface, 7. The laser beam recording apparatus according to claim 6, wherein the recording operation is prohibited while being displayed on the display means.