JPH0157767B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a beam deflection device for deflecting a beam irradiated onto a member to be irradiated with the beam, and further relates to a beam deflection device for detecting the position of the deflected beam. The present invention relates to a beam deflection device having a beam detector.

[Prior Art] In a device that outputs information by scanning a beam irradiated member with a deflected beam, in order to keep the information output position on the beam irradiated member constant, one part of the beam scanning path is A beam detector is installed in the section.

That is, by starting to modulate the beam with an information signal in synchronization with the time when the beam is detected by this beam detector, the information output start positions are aligned.

In a beam deflection device using such a beam detector, the beam is detected as described above, and since the beam detection signal is used for horizontal synchronization of the recording signal, the transmission line of the beam detection signal is If noise is mixed into the image, the information output on the irradiated member will be out of synchronization, making it very unsightly.

〔the purpose〕

The present invention has been made in view of the above points, and provides a beam deflection device that focuses on the periodicity of beam detection signals and can output high-quality information without synchronization deviation by predicting the timing of generation of beam detection signals. It is something to do.

That is, the present invention includes a beam generating means for generating a beam, a deflecting means for deflecting the beam generated by the beam generating means, and a detection signal by detecting that the beam deflected by the deflecting means has arrived at a specific position. a beam detecting means for forming a beam, and an applying means for applying the detection signal as a synchronization signal to a drive signal forming means for forming a drive signal for information recording that controls emission of the beam from the beam generating means, The applying means predicts the time to obtain the detection signal periodically formed by the beam detection means, and applies the detection signal to the drive signal forming means when the detection signal is input at a time other than the predicted time. The present invention provides a beam deflection device comprising a blocking/permitting means for blocking the detection signal and permitting application of the detection signal to the drive signal forming means when the detection signal is input at a predicted time.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

1 is a recording section using an electrophotographic process.
23910 and those described in Japanese Patent Publication No. 43-24748 can be used. 2 is the recording section 1
3 is a photosensitive drum, and 3 is an insulating layer of a drum-shaped photosensitive plate (photosensitive drum) whose basic components are a conductive support, a photoconductive layer, and an insulating layer. The surface is uniformly charged positively or negatively by the first corona charger 5, and charges having a polarity opposite to the charging polarity are captured at the interface between the photoconductive layer and the insulating layer or inside the photoconductive layer. Then, at the same time, the surface of the insulating layer to be charged is irradiated with the laser beam 7, the AC corona discharger 6
applying alternating current corona discharge to form a pattern on the surface of the insulating layer due to a difference in surface potential that occurs according to the light and dark pattern of the laser beam 7, and uniformly exposing the surface of the insulating layer to light with a lamp 8; After forming a high-contrast electrostatic image on the surface of the insulating layer and visualizing the electrostatic image by developing it with a developer mainly composed of charged colored particles using a developer 9, a positive charger 10 is applied. Thereafter, the image is transferred to a transfer material 11 such as paper by a transfer charger 13. Also, the post-exposure lamp 12 then lowers the resistance of the photoconductive layer. The separator 18 separates the transfer paper 11 from the photosensitive drum 3 with a separation belt 19, and then fixes the transferred image with a fixing device 20 using an infrared lamp, a hot plate, etc. to obtain an electrophotographic print image. On the other hand, the surface of the insulating layer on which the transfer has been performed is cleaned by a cleaning device 22 to remove remaining charged particles, and the resistance of the photoconductive layer is lowered by an exposure lamp 4.
is used repeatedly.

Note that 15 indicates a paper feed roller, and this paper feed roller 15, which is constantly rotating, is set to 1.
By lowering the sheet of transfer material 11 onto the layered transfer material 11 in 1-1, one sheet of transfer material 11 is sent out along the conveyance path, and the transfer material 11 is transferred after timing the feeding with timing rollers 16 and 17. Send it to the location.

The transfer material 11 to which the toner image has been transferred is fixed by a fixing device 20, and then transferred to a paper feed roller 2.
1, the paper is discharged onto the paper discharge plate 14.

The photosensitive drum 3 is an endless photosensitive drum, and is rotationally driven by a motor 8-1 via a gear or a pulley (not shown), and a part of the photosensitive drum 3 is provided with a clock. A disk 3-2 is fixed, and a clock pulse is derived by detecting passage through a slit 3-3 provided on the disk using a lamp and a light receiving element provided so as to sandwich the disk. It is what it is. This clock pulse is generated at 31.5 times per revolution of the drum 3, and is used as a control signal for controlling the electrophotographic process.

The periphery of the recording section and the optical section 2 in this recording apparatus will be explained using FIG. A laser unit 23 having a semiconductor laser element is fixed to the outside of the casing 24 of the optical section 2, and the laser beam emitted from this laser unit 23 passes through a beam expander optical system 25 fixed to the casing 24. The light is incident on the entrance window 27 of the deflector 26.

This deflector deflects an incident beam by rotating, for example, a regular octahedral polygon mirror with a motor, and the deflected beam is transmitted by an f-θ lens 28 fixed to an exit window of the deflector 26. It is deflected at a constant speed over the recording area on the photosensitive drum 3.

Incidentally, in the case 2, a slit 29 is provided in the path of the deflected beam.

A part of the housing 30 surrounding the recording device includes:
An opening (not shown) facing the filter 31 is provided, and the air sucked by the fan 32 and purified through the filter 31 is divided into two directions by the air baffle plate 33 and flows in one direction. The air cools the laser unit and the other cools the control circuit units 34, 35 of the recording device. A power supply section 37 is provided below the recording section 1 and the optical section 2, which are separated by a separation plate 36, and inside this power supply section 37, a low voltage power supply 3 is fixed to a stand 38.
9. Install a high voltage power supply 40, and move the stand 38 to the arrow 41-1
By pulling it out in the direction shown in FIG.

(Optical Section) Next, the optical section 2 will be further described in detail using FIG. 3.

FIG. 3 is a top view of the recording device showing the optical section 2. FIG.

An optical unit housing (optical box) 24 is disposed on the right side of the photosensitive drum 3, whose rotation shaft 41 is rotatably supported by the housing 30, and the optical box 24 includes:
All members for forming a laser beam necessary to irradiate the photosensitive drum 3 are arranged.

The semiconductor laser device 48 has a collimator lens 49
The laser unit 23 is integrated with the laser unit 23.

The semiconductor laser device 48 oscillates a laser beam whose strength is modulated in response to an external input signal, and the laser beam enters a collimator lens 49 . The semiconductor laser device 48 and the collimator lens 49 are connected by a jig, so that the laser beam is aligned with the collimator lens 49.
The light emitting surface is adjusted so that it coincides with the optical axis of the collimator lens 49, and the light emitting surface coincides with the focal point of the collimator lens 49. By adjusting these, the laser beam oscillated by the semiconductor laser device 48 is transmitted to the collimator lens 49.
After passing, it becomes a parallel beam that coincides with the optical axis of the collimator lens.

The parallel beam emitted from the collimator lens 49 is guided to the entrance aperture of the beam expander optical system 25. The beam expander 25 shapes the laser beam having a beam pattern as shown in 52 emitted from the collimator lens 49 into a laser beam having a beam pattern as shown in 53 suitable for forming an image on the photosensitive drum 3 as a spot light. Although it is inserted for this purpose, it is not necessarily necessary and may be removed.

The laser beam emitted after being swept almost horizontally by the polygon mirror 26 constituting the deflector is f-
An image is formed on the photosensitive drum 3 as a spot light by an imaging lens 28 having a θ characteristic. The polygon mirror and the imaging lens 28 are integrated to form a deflector unit 46.

The beam detector unit has one reflecting mirror 55.
A slit plate 56 with a small entrance slit and a photoelectric conversion element 57 with a fast response time (for example,
DIN diode). The beam detector unit 58 detects the position of the swept laser beam, and uses this detection signal to determine the start timing of an input signal to the semiconductor laser element for providing desired optical information on the photosensitive drum 3. As a result, it is possible to significantly reduce the synchronization deviation of horizontal signals due to uneven rotation of the polygon mirror, and not only can high-quality images be obtained, but also the tolerance range of accuracy required for polygon mirrors has been widened, and it can be manufactured at a lower cost. be. The beam detector unit 58 is positioned and attached to the optical box 24 by two positioning pins.

The laser beam modulated as described above is irradiated onto the photosensitive drum 3, visualized by the electrophotographic process described above, and then transferred and fixed onto a transfer material 11 made of plain paper and output as a hard copy.

As mentioned above, the laser beam swept by the polygon mirror is guided to the beam detection unit 58 including the reflection mirror 55. The beam detection unit 58 is equipped with a photoelectric conversion element 57, which detects the position of the swept laser beam and uses this detection signal to convert the semiconductor laser element to provide desired optical information onto the photosensitive drum 3. Controls the start timing of the input signal. However, the photoelectric conversion element 57 has the disadvantage that it is prone to malfunction due to ambient electrical noise. Therefore, in this device, the area around the photoelectric conversion element 57 is electrically shielded to prevent malfunction. Further, the photoelectric conversion element 57 and the beam detection unit 58 are positioned with respect to the optical box 24, and the reproducibility and compatibility when they are attached and detached are excellent.

(Control Unit) Next, the control unit 100 of the recording apparatus will be explained in more detail with reference to FIGS. 4 to 7.

Reference numeral 46 indicates the aforementioned deflector unit, and this deflector unit 46 is driven at a constant speed by the drive circuit 104.
A speed signal sent from the deflector unit 46 is applied to the error detector 106 to determine whether the deflector unit 46 is rotating normally. The determination result is applied to the display 123 for display, and is also applied to the sequence controller 103.

48 is a semiconductor laser device including a semiconductor laser element, a Peltier element, and a thermistor;
A Peltier drive circuit 110 controls the semiconductor laser element to maintain a constant temperature.

A temperature signal indicating the temperature of the semiconductor laser device 48 is applied to an error detector 112, and it is determined whether the semiconductor laser device 48 is at a predetermined temperature. This determination result is applied to the sequence controller 103 and displayed on the display 124.

By emitting the laser beam from the semiconductor laser device 48 and rotating the deflector unit 46, the beam is detected by the beam detector 105 including the photoelectric conversion element 57, and a beam detection signal is sent to the error detector 106. error detector 106,
Print sequence controller 103, controller 102 via interface 101
send to.

The error detector 106 determines whether or not beam detection signals arrive at predetermined intervals, applies the determination result to the sequence controller 103, and displays it on the display 124. The error detector 106 also forms an unblanking signal for emitting the semiconductor laser beam so that the beam detector 105 can detect the beam.

The recording signal sent from the controller 102 is sent to the laser drive circuit 10 via the interface 101 and the print sequence controller 103.
9, and the unblanking signal is also applied to this laser drive circuit 109. Since the laser drive circuit 109 causes a current to flow through the semiconductor laser element in accordance with the applied signal, a laser beam is emitted from the semiconductor laser element in accordance with the applied current.
Note that such a controller 102 is, for example, a
Since it is disclosed in No.-32543 etc., detailed explanation will be omitted.

A detector 115 detects the temperature of the heater 107 constituting the fixing device 20, and a control detector 116 detects the temperature detected by the detector.
The heater 107 is controlled so that the fixing device 20 reaches a predetermined temperature. Further, it is detected whether or not the fixing device 20 is at a predetermined temperature, and the detection result is applied to the sequence controller 103 and displayed on the display 124.

Reference numeral 117 indicates a clock pulse generator including the clock disk 3-2, and the clock pulses generated by the pulse generator 117 are applied to the print sequence controller 103 via an error detector 118. At the same time, the error detector 118 determines whether or not a normal clock pulse has been derived, and the determination result is applied to the sequence controller 103 and displayed on the display 124.

Note that this clock pulse is used by a throughput improvement circuit 120 and a jam detection circuit 122, which will be described later.
is also applied.

Reference numeral 126 indicates AC parts such as a motor, a high-voltage power supply necessary for the electrophotographic process, and a paper feed solenoid, and these AC parts are driven by the output of the drive circuit 125 driven by the sequence controller 103. It is something. Reference numeral 128 indicates a plurality of exposure lamps;
8 is controlled by a sequential lighting circuit 127 controlled by the sequence controller 103 to turn on the lights in sequence.

A developing unit 130 detects the developer level and toner concentration signals and sends them to the print sequence controller 103. 1
13 is a service panel that includes a cancel switch and a copy number counter, and when the cancel switch is turned on, an error detector 1 is sent to the sequence controller 103.
14 sends a cancel signal to stop the operation of the recording apparatus, and also sends a cancel signal to the controller 102 via the interface 101 to stop sending out the recording signal.

The error detector 114 also determines whether or not the copy number counter is operating normally. If it is not operating normally, the error detector 114 sends a cancel signal to the sequence controller 103, and furthermore, the controller 103 sends a cancel signal to the display device 124. It is displayed accordingly.

A cassette detector 119 determines whether the cassette 11-1 containing the transfer material 11 is large, medium, or small, derives a cassette size signal, and further detects the cassette 11-1. A paper presence/absence detector detects whether the transfer material 11 is present in the cassette 1, and the presence/absence of paper and a cassette size signal are sent to the sequence controller 103, and further displayed on the display 131 by the sequence controller 103. Ru. Further, the cassette size signal is applied to the throughput improvement circuit 120, which receives the paper size (large, medium, small) signal applied from the controller 102 via the interface 101. A determination signal for determining the interval between latent images formed on the photosensitive drum 3 is generated based on the cassette size signal, and this signal is applied to the sequence controller 103 and the controller 102. In the cassette according to this embodiment, one size of cassette,
For example, since the large cassette is designed to accommodate three types of transfer material (large, medium, and small), the cassette size is notified from the cassette body, and the cassette size is notified by the controller 102 or manual paper size switch 132. This also specifies the paper size.

Reference numeral 121 indicates an ejected paper detection circuit that detects that printed paper is ejected to the tray, and detects the detection signal obtained by this circuit and the gate signal determined by the paper size signal by the detection circuit 1.
22 to determine whether the transfer material has not reached the discharge port of the recording device and is stagnating therein, or has jammed at the discharge port, and sends the determination result to the sequence controller 103. Furthermore, the controller 103 causes the display 131 to
Display in . Note that the circuits 106, 112, 11
6 and 118 are gated by timing pulses from the sequence controller 103 to detect errors.

In the control unit 100 as described above, when a power ON signal as shown in FIG. Start.

The sequence controller 103 turns on the detectors 106, 112, 114, 116, 11 after a time T (for example, 60 seconds) after receiving the power ON signal.
8 indicates normal operation, and the cassette detector 119
It is determined whether the developing unit 130 notifies the existence of paper, and whether the developing unit 130 notifies that the developer is present, the toner density is OK, and there is no jam. If all of the above are normal, a ready signal (ready signal) as shown in FIG. ) is sent to the controller 102, and the ready state is displayed on the display 131. This time T is a warming-up time, during which the deflector is rotated to a predetermined value, the fixing device is heated to a predetermined temperature, and each component is set up.

When the controller 102 side receives such a ready signal, it sends the paper size signal (consisting of 2 bits) shown in FIG. Start signal to interface 101
The data is sent to the sequence controller 103 via. The sequence controller 103 side synchronizes with the clock pulses obtained by the clock pulse generator 117 to form a top signal shown in FIG.
Send to the 2nd side. This top signal is used as a vertical synchronization signal for the image formed on the photosensitive drum, and at the same time is used by the AC drive circuit 125 and the sequential lighting circuit 127.
This is used as a trigger signal to start driving according to the electrophotographic process.

The controller 102 starts sending out the recording signal shown in FIG. 5G after a time t1 after the top signal is derived, and this time t1 determines how much blank space is to be formed at the top or bottom of the transfer material. This is what we are doing. However, the paper feed signal is issued after a predetermined period of time after the top signal is derived.

In FIG. 5, H indicates a beam detection signal, which serves as a horizontal synchronization signal for an image formed on the photosensitive drum 3. The transmission of the recording signal starts at a time t after the beam detection signal is detected.
This time t2 is used to determine how much blank space is to be formed on the left or right side of the transfer material.

Note that the time axis of the recording signal shown in FIG. 5G is shown in a highly compressed manner, and in reality, a recording signal of 2000 bits or more is transmitted during one cycle of the beam detection signal.

In this way, the sequence controller 10
The recording signal sent to the laser drive circuit 10
9 to control the emission of the laser beam.

If the recording device generates a jam during recording, the sequence controller 103 uses this jam signal to stop the print sequence, and at the same time calculates the number of sheets of transfer material remaining in the recording device, and prints out the paper beforehand corresponding to the number of sheets. The controller 102 is requested to retransmit the recording signal starting from page .

(Sequence Controller) Here, the sequence controller 103 will be described in more detail.

FIG. 6 shows a more detailed block diagram of the sequence controller, and FIG. 7 shows its timing chart. The sequence controller 103 includes flip-flops 140 to 145, 157, a gate circuit 146, and AND circuits 147, 148, 15.
6, counter decoder 149, OR circuit 150,
151, timer 152, 153, buffer circuit 1
54, and a power up preset circuit 155.

When the recording apparatus is powered on by the power ON signal, one reset pulse is output from the power reset circuit 155. This circuit is an integrating circuit using a known CR. This reset pulse passes through a buffer 154 and is supplied to each section as a power up reset signal. This reset pulse is input to the OR circuit 150, and its output sets the flip-flop 141, and the output of the flip-flop 141 is as shown in FIG.
25 and supplies power to the AC components.
The output of the OR circuit 150 is also input as a set input to the flip-flop 140, and the set output of the flip-flop 140 is input to the AND circuit 15.
6 to turn on the circuit, and send a clock pulse as shown in FIG. 7H to the counter decoder 149.
Send to. At the same time, this flip-flop 140
The output signal becomes the drum drive signal and the drum begins to rotate. Note that since the flip-flop 157 is not set, the gate circuit 146 remains closed. Further, the output signal of the OR gate 150 is input to the counter decoder 149 and clears the counter included in the counter decoder 149. The counter decoder 149 is composed of a counter, a decoder, and an OR circuit, and 117
It counts the clock pulses from the oscillator and generates the various driving signals necessary to carry out the electrophotographic process. For example, the flip-flop 143 is set at TA timing and reset at TG timing. This signal becomes a high voltage drive signal. Also, flip-flop 1 at TB-timing
44 and reset at TF-timing. This signal becomes an exposure lamp drive signal. In this way, after performing the preprocessing necessary for the electrophotographic process, if the print start signal described above does not come, a drum stop signal is output from the signal line SLI of the counter decoder 149, and the flip-flops 157 and 140 are reset. , timer 15
Set 2. By resetting flip-flop 140, the drum is stopped and AND gate 156 is turned OFF. Further, as described above, the timer 152 is started and the flip-flop 141 is reset after a certain period of time, for example, 60 seconds. This de-energizes the AC components and turns them off. The output signal of this timer 152 is called an auto shutter off signal. Reference numeral 147 indicates an AND circuit for generating the recording device ready signal, and its input signals include a scanner ready signal, a beam detect (BD) ready signal, a peltier ready signal, a heater ready signal, a clock pulse ready signal, and a cancel switch. These are the off signal, the signal that informs that the counter is connected normally, the developer liquid present signal for the liquid developer, the toner signal, the paper present signal for the cassette, and the no jam signal, and all the signals have arrived. The recording device ready signal is derived only when the recording device is ready. On the other hand, the power up preset signal sets timer 153. The time of the timer 153 may be set, for example, to the maximum value of the warm-up time of each device constituting the recording apparatus. This timer 1.53
The output of is input to the OR circuit 151. The other input of the OR circuit 151 is a scanner ready signal,
This is the output signal of the AND circuit 148 to which the BD ready signal, the Peltier ready signal, and the fixing device heater ready signal are applied. The output signal of the OR circuit 151 sets the flip-flop 145, and the set output signal of the flip-flop 145 is a warming-up completion signal and is sent to the error detection circuit shown in FIG. 4 as a timing signal for checking the ready state. do. flipflop 14
5 is reset by a power up preset signal.

The ready conditions for each device are completed and gate 1
The ready signal from 47 is sent to interface 10.
1 to the controller 102, the controller sends a print start signal as shown in FIG. 7A (same as that shown in FIG. 5E). The print start signal sets flip-flop 157, and its set output signal is sent to gate circuit 146, which opens gate 146. On the other hand, the print start signal is OR circuit 1
The output of OR gate 150 is also applied to set flip-flops 140 and 141, as in the case of the power up preset signal described previously, but since these flip-flops are already set, their state does not change. do not.
In addition, the output of the OR gate 150 further clears the counter decoder 149 and outputs it to the counter decoder 149.
starts counting clock pulses. This begins the electrophotographic process. An exposure lamp drive signal is outputted as an output signal TB of the counter decoder 149, and a high voltage circuit drive signal is outputted as TA. Subsequently, the print execution start signal (derived on the signal line SL2) shown in FIG. The print execution signal shown in FIG. 7D is obtained.
The counter decoder 149 outputs the print end signal shown in FIG. 7E to the gate circuit 1 at timing TE.
At the same time, output to signal line SL4 via 46,
The flip-flop 142 is reset and the print execution signal is turned off. The counter decoder 14
9 outputs the paper feed signal shown in FIG. 7F at timing TD. If the print start signal continues to come as shown in FIG. 7, the counter decoder 149 is cleared through the OR circuit 150.
Therefore, a sequence similar to that described above begins, and the seventh
The timing will be as shown in the figure.

When the next print start signal comes before timings TF and TG, flip-flops 143 and 144 are not reset and continue to be driven as shown in FIG. 7G. Also TA, TB, TD, TE,
The timing of TF and TG is determined by the electrophotographic process, so TA=TB or TF
=TG is fine. In addition, in the timing chart shown in FIG. 7, the time from the print start signal to the print execution signal or the time from the paper feed signal depends on the print main body, cassette, transport system,
Determined by the mechanical distance between the drum and the exposure charger.

As described above, the sequence controller 103 generates drive signals necessary for the electrophotographic process and signals necessary for various error detection circuits. In the embodiment shown in FIG. 6, the scanner was explained as being constantly rotating after the power was turned on. It can also be configured to stop.

(Self-diagnosis) Next, details of the self-diagnosis function of the recording device will be explained below.

The self-diagnosis of the recording device is (1) Diagnosis of lack of consumables such as lack of developer, out of paper, empty toner bottle, etc.

(2) Diagnosis of temporary malfunctions such as paper jams and misprints.

(3) Diagnosis of element or circuit failures such as scanner failure, beam detection failure, Peltier element temperature control failure, fuser failure, drum clock failure, and counter disconnection.

(4) Diagnosis of operator operations such as cancel switch and test switch.

It is roughly divided into four types.

(1) Diagnosis of shortage of consumables is for prompt replenishment of supplies.

(2) Diagnosis of temporary malfunctions involves diagnosing paper jams or misprints, notifying the operator, having the operator promptly remove the jammed paper or misprinted paper, and ensuring normal operation. The purpose is to restore operation.

(3) Element or circuit failure diagnosis is to facilitate unit replacement and reduce downtime by diagnosing and displaying the failure location.

(4) Operator operation diagnosis eliminates troubles caused by operator errors by clearly instructing operators when they operate a switch by mistake.

This self-diagnosis of the recording device involves performing individual diagnoses such as (1) to (4), and then, as a comprehensive diagnosis, determining whether the recording device is currently in a wait state, ready state, or error state. is diagnosed and displayed on the display 131. Wait state is when the recording device is warming up, or when the recording device is not recording for a long time or is left with the power on, the auto-shaft-off function that automatically turns off the power to unnecessary electrical parts is activated. The display 131
The weight lamp inside lights up.

The ready state is a state in which no errors or mistakes have been detected as a result of individual self-diagnosis, warm-up has been completed, and the printer is ready to print at any time, and the ready lamp on the display 131 lights up.

The error state is a state in which self-diagnosis has detected some kind of error, and the display 131 or the display 123,
The error lamp in 124 blinks.

By performing such comprehensive self-diagnosis and individual self-diagnosis, recording equipment downtime is reduced, utilization rate is increased, service is facilitated, service cost is lowered, and it is user-friendly for operators. The purpose of the above-mentioned self-diagnosis is to make the device compliant.

An embodiment of the self-diagnosis function will be described below in detail with reference to the drawings.

(Error Detection Circuit) First, the error detection circuit 106 for detecting scanner errors and beam detection errors will be explained with reference to the block diagram of FIG. The error detection circuit 106 detects whether the scanner and beam detection signals become ready within a specified time after power-on, and generates a ready signal when the scanner becomes ready. Also, if the scanner deviates from the normal rotation during printing or the beam detection signal (hereinafter referred to as BD signal) deviates from the normal cycle, the scanner error signal or
Generate a BD error signal and hold it.

A high level scanner ready signal, which is generated when the scanner reaches a predetermined rotation, enters gate 201 via terminal 200. At this time, the recording section 1
When the warm-up end signal derived from the end of the warm-up is applied to the terminal 202, the gate 201 opens and the scanner ready signal passes through the gate 201 and is displayed on the display 124 to notify the scanner ready. At the same time,
Scanner error hold flip flop 20
Enter 5.

On the other hand, a high-level print execution signal derived during printing is applied to a terminal 206 and is passed through an OR circuit 207 to a flip-flop 205.
Enters the clear terminal of the BD error hold flip-flop 208. Therefore, this OR circuit output enables the flip-flops 205 and 208 only during printing (while the print execution signal is being derived) and remains in the clear state during other periods. However, when a scanner error or a BD error occurs, the error signal is detected by the sequence controller 103 and the print execution signal is held to prevent the flip-flops 205 and 208 from being cleared. Clearing in this case is performed by turning on the restart switch 209 and applying a low level signal to the clear terminal via the OR circuit 207. A signal obtained by dividing the output (FIG. 9A) of a crystal oscillator 210 (its oscillation frequency is 1 MHz) to about 244 Hz by a dividing period 211 is applied to the flip-flop 205 as a clock. Therefore, this flip-flop 205
takes in the scanner ready signal in synchronization with the clock signal only during printing, and holds that state if the signal to the terminal becomes high level even once (when an error is detected).

The BD signal applied to the terminal 212 consists of a pulse signal as shown in FIG.
13 to generate a pulse signal of a constant width as shown in FIG. 9C. This constant width pulse signal is further applied to a synchronous single pulse generator 214, which is synchronized with the pulse signal oscillated by the oscillator 210 at the rise of the pulse signal derived from the one-shot multi 213. A single pulse as shown in FIG. 9D is generated. The pulse signal generated by pulse generator 214 is applied to the synchronous clear input of counter 216 through OR circuit 215.

This counter 216 is connected to the crystal oscillator 210.
(oscillation frequency 1MHz) is counted.
The count starts when it is cleared by a pulse from the pulse generator 214 synchronized with the BD signal.

When the output pulses of the crystal oscillator 210 have been counted 1360, the counter 216 outputs the pulse shown in FIG. 9E. This pulse E is applied to a JK flip-flop 217 which generates an unblanking signal.
The unblanking signal is input to the J input of , and the unblanking signal is raised as shown in FIG. 9F. Next, when counting 1856, the counter outputs the pulse G shown in FIG. 9G. This is the J of the JK flip-flop 218 that generates the signal that determines the permissible range of the BD signal.
Enters the input and causes the BD tolerance range signal to rise. This tolerance signal falls when the output of the pulse generator 214 or the 1888 count output of the counter 216 is derived via the OR circuits 215 and 221. This BD tolerance signal is for issuing a BD ready signal when the one-shot multi 213 changes from low level to high level while the tolerance signal is at a high level, and the tolerance range is from 1856 to 1888 counts of the counter 216. This is the area up to. If the pulse D is output from the pulse generator 214 during this period and clears the counter 216 and flip-flop 218, the counter 216
1888 count Before the power comes out, flip-flop 2
18 and counter 216 will be cleared. The BD tolerance signal is applied to the flip-flop 219, and the output of the one-shot multi 213 is applied to the clock terminal CK of the flip-flop 219, and the output of the one-shot multi 213 is applied to the clear terminal CL of the flip-flop 219.
1888 count output is applied. Therefore,
This flip-flop 219 has a counter 216
One shot multi 213 before counting 1888
When the output is derived, the Q terminal is set to high level. Figure 9H shows flip-flop 21
This shows when the Q output of No. 9 goes from low to high, that is, when the BD signal goes from not-ready to ready.

When the BD signal does not arrive immediately or is derived outside the allowable range, the counter 216 returns 1888.
A count output is output on the signal line 220, the output passes through the OR circuit 221, enters the OR circuit 215, and at the same time clears the counter 216.
Flip-flop 219 to detect BD ready
is cleared, so the output of the flip-flop 219 becomes low level, indicating that the BD signal is not ready. This BD ready signal is outputted to the outside through the terminal 222.

Also, if the BD signal is input before the counter 216 reaches 1856 counts, the flip-flop 2
When the output of 18 is low, the D flip-flop 21
9 performs sampling, so its output becomes a low level. In this way, when the period of the BD signal is not normal, the BD ready detection flip-flop 21
The output of 9 becomes low level and it is detected that it is not ready. BD tolerance range starts from 1856 counts
The count is 1888, but this is due to the period of the BD signal.
Since it is 1.875 ms, the range was determined taking into account scanner jitter, etc., and it is possible to expand or reduce the range beyond this.

One input terminal 229 of the OR circuit 221 is a terminal to which a power up preset signal is applied, and is used to clear the counter 216 and the flip-flop when the recording apparatus is powered on.

The BD ready signal is outputted to the terminal 222 and simultaneously passed through the gate 223 which is opened by the warm-up end signal, and is displayed on the display 124.
to go into. This flip-flop 208 is prohibited from being cleared because the output of the OR circuit 207 becomes high level during printing. and
If the BD ready signal changes to low level even once during printing, it is held and sent to terminal 224.
Derive the BD error signal.

Once a BD error is detected, the print execution signal is held by a circuit (not shown) in the same way as when a scanner error occurs, and the output of the flip-flop 208 is held until the switch 209 is turned on.

When either the scanner error signal or the BD error signal is derived, the recording device stops further printing operations. As a result, when a misprint occurs due to a scanner or beam detection error and the printer stops, you can see the print check request display, remove the misprinted paper, and press the restart button to restart the printer. In the event of an error, this printer sends a data retransmission request signal to the controller so that the erroneous data can be retransmitted.

It has been partially mentioned above that the counter 216 for detecting BD ready generates an unblanking signal, but the details will now be described in more detail.

In order to know when the beam, which scans at a fixed period, has arrived at a fixed position, the laser must be aimed at the vicinity where the beam detector is located. Then, once the beam passes through the beam detector, the laser is turned off, and the laser is turned on between recording areas on the photosensitive drum according to the recording signal, and when the recording area ends, the laser is turned on after a certain period of time has elapsed, and the next beam is detected. Prepare for.
If beam detection is not performed at regular intervals, a function is required to keep the laser on and check the beam position. This function is realized by the unblanking signal generation section, which is part of the BD
Costs are reduced by partially using the ready detection section. Determining the unblanking period has problems unique to semiconductor lasers.

When a semiconductor laser is pulse-driven, the temperature at the junction changes due to internal transient thermal resistance. When the light is first turned on, the temperature is low and the luminous efficiency is high, but since the heat generated cannot escape, the temperature at the junction increases and the luminous efficiency decreases. This situation is shown in FIG. FIG. 10A shows changes in the amount of emitted light during pulse operation. Here, the T1 period is an unblanking period in which a beam is emitted, T2 and T3 are periods in which a beam is not emitted, and T4 is a recording area scanning period in which a beam is emitted in accordance with a recording signal. The peak height b can be several times the steady state height a. However, the vertical axis indicates the amount of light of the beam. Figure 10B
As shown in the figure, the light amount has a peak value in the T1 period, but there is not much of a peak in the T1 period following the T4 period. This is because the temperature of the junction of the semiconductor laser element has increased because the laser was emitting light in accordance with the recording signal during the T4 period. Therefore, when the beam position is detected at the beginning of the unblanking period, the heights of the detection signals P1 and P2 vary as shown in FIG. 10C. Figure 10D shows a comparison of this by enlarging the time axis.If such signals P1 and P2 are sliced at a constant level E1, a shift in the rising and falling timing of the pulses will occur as shown in Figure 10E. . In order to avoid such a phenomenon, the amount of light during the unblanking period must be kept constant. For this reason, automatic control of the amount of light may be considered, but there is a risk of increased costs and a runaway feedback system that could damage the laser. Even if this light amount control is not performed, the unblanking period is extended until the light amount fluctuation due to the change in transient thermal resistance becomes steady, and the beam position is detected immediately at the end of the unblanking period as shown in Figure 10F. This will prevent jitters after slicing. However, in terms of the lifespan of the semiconductor laser, it is better to keep the laser lighting time as short as possible. The unblanking period is determined in consideration of the relationships described above. This unblanking signal generation is performed by the JK flip-flop 217. The output of this flip-flop 217 becomes high level as shown in FIG. 9F when the counter 216 counts 1360, and becomes low level when a pulse is output from the pulse generator 214. As long as the BD signal is input at regular intervals, this flip-flop 2
The output of 17 is outputted to terminal 225 via OR circuit 228 as an unblanking signal. B.D.
BD when the signal is not located within the BD tolerance range
Since the output of the ready detection flip-flop 219 is high level, this flip-flop 21
If the output of 9 is applied to the OR circuit 228, a high level signal can always be obtained from the terminal 225 when the BD signal is not normally derived. Therefore, if the unblanking signal of the terminal 225 and the recording signal applied to the terminal 226 are applied to the OR circuit 227, and the output of the OR circuit 227 is used to drive the semiconductor laser element 74, the BD signal will be correctly output. When the BD signal is being derived, the laser beam is emitted at predetermined intervals as shown in FIG. 10, and when the BD signal is not being normally derived, the laser beam can be emitted at all times.

In this way, when the BD signal does not exist within the preset tolerance range, if the laser beam is turned on all the time, it will definitely occur at some point.
It is possible to obtain a BD signal, and synchronized scanning of the laser beam can be performed again using the BD signal found in this way as a reference.

The BD signal input to the terminal 212 is output to the terminal 260 after its signal width is shaped by the one-shot multi 213.
It is used to horizontally synchronize the recording signal output from the BD signal line, so if noise enters the BD signal line, it will cause a synchronization error and result in an extremely unsightly image. Since this BD signal has periodicity, 1
Once a BD signal is detected, the next time it will be detected can be predicted with a high degree of accuracy. The ready detection of the BD signal detects the coincidence between this predicted cycle and the actually input BD signal by using the BD ready detection flip-flop 21.
9 is detected. Merely predicting the period and detecting whether it is normal is powerless against synchronization errors caused by noise, but if a signal other than the predicted period comes in, blocking it at the input section can prevent noise from entering. It has a remarkable effect on FIG. 11 shows an example in which when a signal with a period other than the predicted period is inputted in this way, the signal is blocked at the input section. Circuits with the same numbers as in FIG. 8 are as follows:
The operation is similar to that shown in FIG. 8. That is, since the signal predicting the cycle is output as a BD tolerance signal to the Q output of the flip-flop 218, this signal is returned to the BD signal input section and gated. A gate 261 is provided at the input of the one-shot multi 213, and a BD tolerance signal is input to the gate 261. But this
If you use the BD tolerance signal as it is as the gate control signal for the BD signal input section, the BD
Since the signal period and the count period of the counter 216 do not match, the BD tolerance signal generated from the output of the counter 216 is out of synchronization with the BD signal, and the gate 261 remains off. Therefore, a means to force synchronization is needed.

The output of the ready detection flip-flop 219 is at a high level in the asynchronous state as described above, and becomes a low level in a synchronous state. Therefore, this output and the BD tolerance signal are connected to the OR circuit 262.
If the output of the OR circuit 262 is applied to the gate 261 as a gate control signal, the gate 261 will be turned on in the asynchronous state, and the one-shot multi will be able to operate whenever the BD signal arrives.
In a synchronous state, asynchronous noise can be blocked.

With this configuration, since the noise of the BD signal input is blocked, erroneous triggering of the one-shot multi 213 is eliminated, and erroneous image synchronization signals are no longer sent from the terminal 260, so that out-of-synchronization images can be prevented.

In the embodiments using drawings, only the recording device that records information on the recording member has been described.
The present invention is not limited to such a recording device, but can of course be applied to a display device that displays information by irradiating a beam onto a beam-irradiated member such as a screen.

〔effect〕

As explained above, according to the present invention, the time to obtain the beam detection signal is predicted, and when a signal other than the predicted time comes in, it is cut off, so that it is possible to prevent the incorporation of noise, etc., and to prevent synchronization. It is possible to output high-quality information without any lag.

[Brief explanation of drawings]

1 to 3 show a recording device to which the present invention is applied, in which FIG. 1 is a side sectional view, FIG. 2 is a perspective view, and FIG.
The figure is a top view. FIG. 4 is a block diagram showing the control section, FIG. 5 is an output waveform diagram of each part in FIG. 4, FIG. 6 is a block diagram showing the sequence controller in FIG. 4 in more detail, and FIG. Figure 6 is an output waveform diagram of each part, Figure 8 is a block diagram showing the error detector in Figure 4 in more detail, and Figure 9 is a diagram showing the error detector in more detail.
Figure 10 is an output waveform diagram of each part in Figure 8, and Figure 1
FIG. 1 is a block diagram showing another embodiment of the error detector. Here, 1 is a recording section, 2 is an optical section, 3 is a photosensitive drum, 11 is a transfer material, 15 is a paper feed roller, 23 is a laser unit, 26 is a deflector, 48 is a semiconductor laser device, 57 is a photoelectric conversion element, 100 is a control unit;
102 is a controller, 103 is a sequence controller, 106 is an error detector, 112 is a Peltier error detection circuit, 114 is an error detection circuit, 116 is a control detector, 118 is an error detector, 120 is a throughput improvement circuit, and 122 is a jam detection circuit. 123, 124, 131 are display devices, 140 to 145, 157 are flip-flops, 146, 148, 156 are AND circuits, 14
9 is a counter decode circuit, 150, 151 is an OR circuit, 152, 153 is a timer circuit, 155
are power up preset circuits, 205, 208,
217 to 219 are flip-flops, 210 is a crystal oscillator, 211 is a frequency divider, 213 is a one-shot multiplier, 214 is a pulse generator, and 216 is a counter.

Claims (1)

[Scope of Claims] 1. Beam generating means for generating a beam, deflecting means for deflecting the beam generated by the beam generating means, and detecting and detecting that the beam deflected by the deflecting means has arrived at a specific position. A beam detection means for forming a signal; and an application means for applying the detection signal as a synchronization signal to the drive signal formation means for forming a drive signal for recording information that controls emission of the beam from the beam generation means. and the applying means predicts when to obtain a detection signal periodically formed by the beam detecting means,
When the detection signal is input at a time other than the predicted time, the application of the detection signal to the drive signal forming means is cut off, and when the detection signal is input at the predicted time, the drive signal forming means for the detection signal is cut off. 1. A beam deflection device comprising a blocking/permitting means for allowing application of