JPH0565850B2 - - 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.

[Conventional technology]

In a device that outputs information by scanning a beam irradiated member with a deflected beam, a beam detector is installed in a part of the beam scanning path in order to keep the information output position on the beam irradiated member constant. has been established.

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.

Further, for example, in order to generate a beam detection signal, it is necessary to determine a timing near the generation timing of the next beam detection signal according to the beam detection signal. However, if the nearby timing is determined based on mixed noise, forced emission of the beam will be performed for beam position detection, for example, at a position different from the beam detection position. If this happens, the beam may not be emitted at the correct position.
Printing becomes impossible.

[Objective] The present invention has been made in view of the above-mentioned points, and prevents erroneous determination of the neighboring timing due to the incorporation of noise, etc., and also prevents erroneous determination of the neighboring timing until the beam detection signal is generated at a predetermined cycle. It is an object of the present invention to provide a beam deflection device capable of preventing determination.

In order to achieve such an object, the present invention provides a beam generating means for generating a beam (corresponding to the semiconductor laser element 74 in FIG. 11 in the embodiment).
and a deflecting means (also corresponding to the deflector 26 in FIGS. 2 and 3) for deflecting the beam generated by the beam generating means, and detecting that the beam deflected by the deflecting means has arrived at a specific position. A beam detection means for forming a signal (also corresponding to the light guide conversion element 57 in FIG. 3), and a timing control for generating a beam detection signal to be generated thereafter in response to a detection signal from the beam detection means. Determining means for determining the nearby period (also corresponds to the counter 216 in FIG. 11)
and permitting/prohibiting means (also corresponding to the gate 261 in FIG. 11) for permitting/prohibiting the receiving of the detection signal from the beam detecting means by the determining means; The beam generation means is driven to emit light continuously until the beam detection signal is generated at a predetermined period, and after the detection signal from the beam detection means is generated at a predetermined period, the beam detection signal is generated in the vicinity of the generation timing of the beam detection signal. It is characterized by comprising a control means (also corresponding to the OR circuit 262 in FIG. 11) that sets the permissible/prohibited means to a permissible state during a period and sets the permissible/prohibited means to a prohibited state outside of the near period. .

[Embodiment] 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. After the transfer paper 11 is separated from the photosensitive drum 3 by a separating belt 19 of a separator 18, the transferred image is fixed by 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 reference numeral 15 indicates a paper feed roller, and by lowering the constantly rotating paper feed roller 15 onto the transfer material 11 stacked in the cassette 11-1, one sheet of the transfer material 11 is transferred. The transfer material 11 is sent out along the conveying path, and after the timing of the feeding is determined by the timing rollers 16 and 17, the transfer material 11 is sent out toward the transfer position.

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 the passage of 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.
31.5 such clock pulses are generated per one rotation of the drum 3, and are used as control signals 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, for example, rotating a regular octahedral polygonal 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. Note that the lower part of the recording section 1 and the optical section 2 is a separation plate 36.
A power supply part 37 is provided which is configured separately from the above, and inside this power supply part 37 there is a low voltage power supply 3 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 4.
After passing through 9, 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 having a small entrance slit and a light guiding conversion element 57 having 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 amplifier ranking 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 also applied to a throughput improvement circuit 120 and a jam detection circuit 122, which will be described later.

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 developer is present, 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. 5B) is output. ) is sent to the controller 102, and the display 131 displays this ready state. 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. On the sequence controller 103 side, the 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 time t2 after this beam detection signal is detected.
This is done later, and this time t2 determines 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
3, the recording signal sent to the laser driving circuit 109
is applied 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 and generates the various drive 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 time 152 starts, 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 to notify that the counter is connected normally, the developer liquid present signal for the liquid developer, the toner present signal, the cassette paper present signal, and the no jam signal. The recording device ready signal is derived only when the recording device is present.
On the other hand, the power-up preset signal is sent to timer 153.
Set. 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
The output of 53 is input to an OR circuit 151. The other input of the OR circuit 151 is an AND circuit 148 to which a scanner ready signal, a BD ready signal, a Peltier ready signal, and a fuser heater ready signal are applied.
is the output signal of 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, which is used as a timing signal for checking the ready state to each error detection circuit shown in FIG. Send. Flip-flop 145 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
As with the power up preset signal mentioned above, the output of OR gate 150 is applied to set flip-flops 140 and 141, but since these flip-flops are already set, their state does not change. .
Further, the output of the OR gate 150 further clears the counter data 149, and 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 sends the print end signal shown in FIG. 7E to the gate circuit 14 at timing TE.
At the same time, the flip-flop 142 is reset and the print execution signal is turned off. The counter decoder 149
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 starts, and the timing is as shown in FIG. 7.

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.

Diagnosis of temporary malfunctions (2) 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 comprehensively determining whether the recording device is currently in a wait state, ready state, or error state. Diagnose and display 131
is displayed. A 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 turned on.
When the auto-shaft-off function, which automatically turns off the power to unnecessary electrical parts, is activated, the display 13
The weight lamp inside 1 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 pulse signal with a constant width is further applied to a synchronous single pulse generator 214, which, at the rising edge of the pulse signal derived from the one-shot multi 213,
A single pulse as shown in FIG. 9D is generated in synchronization with the pulse signal oscillated by the oscillator 210.
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 enters the J input of the JK flip-flop 217 which generates the unblanking signal, and causes the unblanking signal to rise as shown in FIG. 9F. Next, when counting 1856, the counter outputs the pulse G shown in FIG. 9G. This enters the J input of the JK flip-flop 218, which generates a signal that determines the tolerance range of the BD signal, causing the BD tolerance 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 is cleared.
Flip-flop 2 before 1888 count output
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 is 1856 counts to 1888
However, this is because the period of the BD signal is
Since it is 1.875 ms, the range was determined taking into consideration 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 is operated at a certain period, has arrived at a certain position, it is necessary to aim the laser 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 light amount has a peak value in the T1 period, but in the T1 period following the T4 period,
There aren't that many peaks. This is because the laser was emitted according to the recording signal during the T4 period.
This is because the temperature of the junction of the semiconductor laser element is rising. Therefore, if the beam position is detected at the beginning of the unblanking period, the heights of the detection signals P1 and P2 will 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 pulse 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 light intensity control 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 intensity control is not performed, the unblanking period can be extended until the light intensity fluctuation due to the change in transient thermal resistance becomes steady, and the beam position can be detected just at the end of the unblanking period as shown in Figure 10F. If you do this, you can 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.
This flip-flop 217 is a counter 216
When the count reaches 1360, the output becomes high level as shown in FIG. 9F, and when a pulse is output from the pulse generator 214, it becomes low level. As long as the BD signal is input at regular intervals, the output of this flip-flop 217 is sent to the OR circuit 22 as an unblanking signal.
8 to the terminal 225. BD signal
When the BD is not within the permissible range, the output of the BD ready detection flip-flop 219 is at a high level. Therefore, if the output of this flip-flop 219 is applied to the OR circuit 228, the BD signal is normally output from the terminal 225. When not being derived, a high level signal can always be obtained. 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.
This signal is output from the BD signal line and is used to horizontally synchronize the recording signal, so if noise enters the BD signal line, it will cause a synchronization error and result in an extremely unsightly image. This BD signal has periodicity, so once
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 219.
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 embodiment in which when a signal with a period other than the predicted period comes in, this signal is blocked at the input section. Circuits with the same numbers as in FIG. It performs the same operation as shown in the figure. 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 BD
If the tolerance range signal is used as it is as a gate control signal for the BD signal input section, the BD signal cycle and the count cycle of the counter 216 will not match when the power is turned on, so the BD tolerance range signal generated from the counter 216 output will not match the BD signal. Synchronization is not achieved 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 described above, according to the present invention, it is possible to prevent incorrect determination of timings near the generation timing of a beam detection signal due to the mixing of noise, etc., and to prevent the timing from occurring near the timings before the beam detection signal is generated at a predetermined cycle. erroneous decisions can be prevented.

[Brief explanation of the drawing]

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. Figure 4 is a block diagram showing the error control section, Figure 5 is an output waveform diagram of each part in Figure 4, Figure 6 is a block diagram showing the sequence controller in Figure 4 in more detail, and Figure 7 is a block diagram showing the sequence controller in Figure 4 in more detail. 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 block diagram showing the error detector in Figure 4 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
114 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, 122 is a jam detection circuit, 123, 124, 131 is a display, 140 to 145, 157 is a flip-flop, 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 multi, 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; Detecting by detecting that the beam deflected by the deflecting means has arrived at a specific position. beam detection means for forming a signal; determining means for determining a generation timing of a beam detection signal to be generated thereafter in response to a detection signal from the beam detection means; an enabling/prohibiting means for permitting/prohibiting reception of a detection signal from the beam detecting means; and a means for driving the beam generating means to emit light continuously until the detection signal from the beam detecting means is generated at a predetermined period. , after the detection signal from the beam detecting means starts to be generated at a predetermined period, the permitting/prohibiting means is set to the permitting state in a period near the generation timing of the beam detecting signal, and the permitting/prohibiting means is set to the permitting state outside the near period. A beam deflection device comprising: a control means for setting the prohibition means to a prohibited state.