JPH0894948A - Recorder - Google Patents

Abstract

PURPOSE: To effectively obviate the generation of jitters without generating a deviation in processing to specify the respective faces of a polygon mirror even if a sensor for detecting a periodically scanned light beam fails to detect this beam. CONSTITUTION: A synchronizing signal 19 outputted from an SOS sensor 18 is supplied to a horizontal synchronization processing section 61, a pseudo synchronizing signal generating section 62 and a correcting section 63. This pseudo synchronizing signal generating section 62 outputs the pseudo synchronizing signal 64 when the synchronizing signal 19 is not outputted from the SOS sensor 18 even after lapse of a prescribed period. The pseudo synchronizing signal 64 is supplied to the correcting section 63 where the correction of jitters, etc., is executed. The horizontal synchronization processing section 61 sends the horizontal synchronizing signal 22 to a recording information generating section 32 and outputs image data 24 for one line from this section every time of sending by using this result. The horizontal synchronization processing section 61 drives a semiconductor laser 11 by using this image data 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device such as a printer, a copying machine or a facsimile device which forms an image on a photoconductor using a light beam such as a laser beam and records the image.
More specifically, the present invention relates to a recording apparatus in which a polygon mirror is used for scanning a light beam on a photoconductor and a correction process at the time of recording is performed by using a unique correction value for each surface.

[0002]

2. Description of the Related Art A typical example of a recording apparatus that records an image using a light beam is a laser printer. In a laser printer, a laser beam is output from a light source, and the laser beam is output onto a photosensitive body such as a photosensitive drum or a photosensitive belt.
An electrostatic latent image is formed by scanning line by line. The electrostatic latent image is developed using toner particles, and the toner image obtained by this is transferred from the photosensitive member to a sheet. After that, the sheet is fixed by the fixing device and discharged to the discharge tray.

FIG. 4 shows the configuration of the main part of an example of such a conventional recording apparatus. A laser beam 12 output from the semiconductor laser 11 enters a polygon mirror (rotating polygon mirror) 13. The polygon mirror 13 has a polygonal shape, and a plurality of surfaces each constitute a reflecting surface. The polygon mirror 13 is rotated at a high speed by a drive motor (not shown). As the incident surfaces of the laser beam 12 are switched one by one, the laser beam 14 reflected from them changes its traveling direction periodically within a predetermined angle range. As a result, the laser beam 14 that has passed through the lens 15 has the photosensitive drum 1
The surface of 6 is sequentially scanned in the axial direction. The photoconductor drum 16 is rotated at a constant speed in a predetermined rotation direction by a drum motor (not shown).

By the way, an SOS (scanning start) sensor 18 is arranged near the end of the photosensitive drum 16 on the scanning start point side. The SOS sensor 18 detects the passage of the laser beam 14 and outputs a synchronization signal 19 each time. The synchronization signal 19 is the horizontal synchronization processing unit 2
1 is input to control the horizontal synchronization of the laser beam 12. That is, the horizontal synchronization processing unit 21 outputs the horizontal synchronization signal 22 for instructing reading after a predetermined delay time from the arrival of the synchronization signal 19, and the recording information generation unit 23.
To output the image data 24 for one line each time. Based on the image data 24, the semiconductor laser 11 performs on / off control line by line. Here, the output of the horizontal synchronizing signal 22 is delayed from the generation of the synchronizing signal 19 by a certain time because the start point of the on / off control of the laser beam of each line by the image data 24 is set from the fixed position of the photosensitive drum 16. This is to start it accurately.

For this reason, the horizontal synchronization processing unit 21 uses SO
Every time the S sensor 18 outputs the synchronization signal 19, counting by a counter (not shown) is started. Then, the time when the laser beam 14 arrives at the recording start point of each line on the photoconductor drum 16 is predicted, and the modulation of the image data 24 by the semiconductor laser 11 is started at that timing.

However, if the timing of writing an image on the photoconductor drum 16 in each scanning line is set by precisely shifting the timing corresponding to the distance from the SOS sensor 18 to the writing start point, the scanning line of each scanning line can be set. The image is slightly deviated in the scanning direction line by line, which causes so-called jitter.

FIG. 5 shows how this jitter occurs. As a result of the photoconductor drum 16 rotating at a constant speed, the surface thereof moves in the direction indicated by the arrow 31 in the figure. Therefore, the laser beam is periodically scanned on the line including the SOS sensor 18, and
If 8 is the recording of the first pixel P ₁ of each scanning line is performed after passing through a fixed delay time from the output of the synchronizing signal 19, the first pixel P ₁ of each scan line,
P ₁ , ... P ₁ should be aligned in a straight line in the direction of the arrow 31 (sub-scanning direction). However, in reality
As shown in FIG. 5, these positions slightly change in the scanning line direction. Therefore, if this is left as it is,
A slight positional deviation occurs in the image of each scanning line, and the reproducibility of straight line components such as ruled lines drawn in the sub-scanning direction deteriorates.

The main cause of such a jitter is that the processing accuracy of each surface of the polygon mirror 13 is not exactly the same. Therefore, conventionally, each surface of the polygon mirror 13 is grasped and the correction value of the delay time for each surface is calculated. That is, assuming that the polygon mirror 13 is composed of six surfaces, the delay time from the output point of the synchronization signal 19 is independently set for each of these six surfaces, and this is applied. I was trying to eliminate the jitter.

FIG. 6 shows the arrangement of the first pixels P ₁ , P ₁ , ... P ₁ of each jitter-corrected scan line. The first pixel P ₁ , P of each of these scan lines
₁ , ... P ₁ are aligned in a straight line in the direction of arrow 31 (sub-scanning direction). In order to make the drawings easier to understand,
The intervals between the scanning lines are the respective pixels P ₁ , P ₁ , ...
It is expressed widely compared to the size of P ₁ .

FIG. 7 shows a jitter correction circuit disclosed in Japanese Patent Publication No. 4-16987. The synchronization signal 19 is sequentially input from the SOS sensor 18 to the timing pulse generation circuit 41 of this circuit. Based on this, the timing pulse generation circuit 41 generates a pulse signal 42 having a pulse width that falls until it reaches the scheduled time when the next synchronization signal 19 arrives. Supply to. A reset signal 45 is supplied to the counter 43 each time the reference surface detector 44 detects a reference surface of a polygon mirror, which is not shown in the figure, and is input to the reset terminal R thereof. Therefore, the counter 43 outputs a surface identification signal 47 sequentially representing each surface on which the laser beam is incident with reference to the reference surface.

The surface specifying signal 47 is supplied to the analog switch 48. The analog switch 48 includes as many voltage setting devices as the number (n + 1) of faces of the polygon mirror, and presets the voltages V _{0 to} V _n corresponding to the correction values of the respective faces. Then, the surface identification signal 4
Each time 7 is input, the voltage of the surface represented by this is selected and sent to the driver 51 as a correction signal 49. The image data 24 is supplied to the driver 51, and the diffraction angle of the acousto-optic modulator 53 is changed by the carrier frequency 52 based on the correction value represented by the correction signal 49, and the above-mentioned jitter is generated. It is designed to prevent the occurrence of.

[0012]

As described above, in the conventional recording apparatus, the counter 43 is generally operated on the basis of the synchronization signal 19, and each surface of the polygon mirror is associated with the count value. . However, in such a recording apparatus, when noise is generated, the SOS sensor 18 cannot detect the laser beam by accident due to vibration inside the apparatus, or the laser beam itself is cut off, Correspondence between the count value and the surface of the polygon mirror goes wrong. As a result,
It becomes impossible to correct the jitter when recording the image.

In the recording apparatus disclosed in Japanese Patent Publication No. 4-16987, the reference plane is detected. Therefore, when the next reference plane is detected, the correspondence error is corrected. However, for this purpose, a special mechanism for detecting the reference surface of the polygon mirror rotating at high speed is required. In a recording apparatus of the type in which the correction value for each surface is set while the polygon mirror is actually rotated without detecting such a reference surface, the deviation continues once the correspondence is lost.

Therefore, an object of the present invention is to make a mistake in the process for specifying each surface of the polygon mirror even if the sensor for detecting the light beam which is periodically scanned fails in the detection. It is to provide a recording device that does not.

Another object of the present invention is to obtain an image of each scanning line on the photoconductor even if the sensor for detecting the periodically scanned light beam fails in the detection. An object of the present invention is to provide a recording device that does not cause a write position error.

[0016]

According to a first aspect of the invention, (a) a photosensitive member for forming an image for recording, and (b) a light beam directed from one end to the other end of the photosensitive member. A polygon mirror for periodically scanning the beam, and (c) is arranged on the scanning path of the light beam to set the scanning timing to 1
A light beam sensor for detecting every cycle, (d) a counter for counting the detection output of this light beam sensor to identify the scanning surface of the polygon mirror, and (e) a light beam for each cycle of the light beam. Sensor output presence / absence determining means for determining whether or not the output of the beam sensor is output, and (f) Count value correction for counting the count value of the counter by 1 each time there is a cycle in which the detection output of the light beam sensor is not output. And means for the recording device.

That is, according to the first aspect of the invention, a polygon mirror is used to scan a light beam such as a laser beam onto a photosensitive member such as a photosensitive drum, and which surface of the polygon mirror is used to scan the light beam. It is determined whether or not the output of the light beam sensor is output for each cycle of the light beam in the recording device that determines whether to perform the process using the light beam sensor arranged on the scanning path of the light beam. The sensor output presence / absence determining means is provided, and when the output is not obtained, the count value correcting means is used to count up or count down the count value of the counter by one. Therefore, the count value of the counter always shows an accurate value, and it is possible to accurately determine which surface of the polygon mirror is used to scan the light beam.

According to the second aspect of the present invention, (a) a photosensitive member for forming an image for recording, and (b) a laser beam is periodically scanned from one end to the other end of the photosensitive member. And (c) an SOS sensor which is disposed further on the scanning start side of the laser beam than the above-mentioned one end of the photosensitive member, and which detects the scanning timing of the laser beam for each cycle, (d) A counter for counting the detection output of the SOS sensor to specify the scanning surface of the polygon mirror, and (e) SO for each cycle of the laser beam.
SOS sensor output presence / absence determining means for determining whether or not the output of the S sensor is output, and (f) when there is a cycle in which the detection output of the SOS sensor is not output, there is a pseudo SOS.
The recording device is provided with a pseudo SOS signal generating means for generating the output of the sensor and supplying it to the counter.

That is, according to the second aspect of the present invention, the polygon mirror is used to scan the laser beam on the photosensitive body such as the photosensitive drum, and which surface of the polygon mirror is used to scan the laser beam. It is determined whether or not the output of the SOS sensor is output for each cycle of the laser beam to the recording device that is determined by using the SOS sensor arranged on the start side of the scanning path of the laser beam.
OS sensor output presence / absence determining means is provided, and when this output is not obtained, the pseudo SOS signal generating means is used to output the pseudo SO.
The S signal is generated and supplied to the counter, and the count value is incremented by one. Therefore, the count value of the counter always shows an accurate value, and it is possible to accurately determine which surface of the polygon mirror is used to scan the laser beam.

According to the third aspect of the present invention, (a) a photosensitive member for forming an image for recording, and (b) a laser beam is periodically scanned from one end to the other end of the photosensitive member. And (c) an SOS sensor which is disposed further on the scanning start side of the laser beam than the above-mentioned one end of the photosensitive member, and which detects the scanning timing of the laser beam for each cycle, (d) A counter for counting the detection output of the SOS sensor to specify the scanning surface of the polygon mirror, and (e) SO for each cycle of the laser beam.
SOS sensor output presence / absence determining means for determining whether or not the output of the S sensor is output, and (f) when there is a cycle in which the detection output of the SOS sensor is not output, there is a pseudo SOS.
Pseudo SOS signal generating means for generating the output of the sensor and supplying it to the counter, and (g) Correction value registration means for registering the correction value of the writing position when the laser beam is written on the photoconductor for each surface of the polygon mirror. The recording device is provided with a writing position correcting unit that reads out a correction value corresponding to the surface specified by the counter (H) from the correction value registering unit and corrects the writing position.

That is, according to the third aspect of the present invention, the polygon mirror is used to scan the laser beam on the photosensitive body such as the photosensitive drum, and which surface of the polygon mirror is used to scan the laser beam. It is determined whether or not the output of the SOS sensor is output for each cycle of the laser beam to the recording device that is determined by using the SOS sensor arranged on the start side of the scanning path of the laser beam.
OS sensor output presence / absence determining means is provided, and when this output is not obtained, the pseudo SOS signal generating means is used to output the pseudo SO.
The S signal is generated and supplied to the counter, and the count value is incremented by one. Therefore, the count value of the counter always shows an accurate value, and it is possible to accurately determine which surface of the polygon mirror is used to scan the laser beam. The recording device is provided with correction value registration means for registering the correction value of the writing position when the laser beam is written on the photoconductor for each surface of the polygon mirror, and reads the correction value based on the determination result. Thus, the recording start position on the photoconductor is corrected.

According to the fourth aspect of the invention, (a) a photosensitive member for forming an image for recording, and (b) a laser beam is periodically scanned from one end to the other end of the photosensitive member. And (c) an SOS sensor which is disposed further on the scanning start side of the laser beam than the above-mentioned one end of the photosensitive member, and which detects the scanning timing of the laser beam for each cycle, (d) A counter for counting the detection output of the SOS sensor to specify the scanning surface of the polygon mirror, and (e) SO for each cycle of the laser beam.
SOS sensor output presence / absence determining means for determining whether or not the output of the S sensor is output, and (f) when there is a cycle in which the detection output of the SOS sensor is not output, there is a pseudo SOS.
Pseudo SOS signal generating means for generating an output of the sensor and supplying it to the counter, and (g) When the pseudo SOS signal generating means pseudo-produces the output of the SOS sensor,
The delay required for the sensor output presence / absence determining means is subtracted to determine whether the next SOS sensor output is present or not S.
The recording device is provided with an OS sensor output presence / absence time adjusting means.

That is, according to the invention of claim 4, the SOS is
As a result of confirming that the output of the SOS sensor is not output by the sensor output presence / absence determining means, the pseudo SOS signal is originally output after the time when the output of the SOS sensor is output. Therefore, the delay due to this is subtracted from the next SOS signal. The presence or absence of the output of the sensor is discriminated so that the check of the presence or absence of the output of the SOS sensor from the next time onward due to the accumulated delay time will not be hindered.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows a circuit configuration of a main part of a recording apparatus according to an embodiment of the present invention. In this figure, the same parts as those in FIG. 4 are designated by the same reference numerals, and the description thereof will be appropriately omitted. In the recording apparatus of this embodiment,
The synchronization signal 19 output from the SOS sensor 18 is supplied not only to the horizontal synchronization processing section 61 but also to the pseudo synchronization signal generation section 62 and the correction section 63. When the synchronization signal 19 is not output from the SOS sensor 18 even after a predetermined period of time has passed, the pseudo synchronization signal generator 62 detects this and outputs a pseudo synchronization signal 64. The pseudo sync signal 64 is supplied to the correction unit 63, where the jitter and the like are corrected. Using this result, the horizontal synchronization processing unit 61 sends the horizontal synchronization signal 22 to the recording information generation unit 23, and each time it outputs the image data 24 for one line. The horizontal synchronization processing unit 61 drives the semiconductor laser 11 using this image data 24. Further, the horizontal synchronization processing section 61 is adapted to turn on the laser beam 14 within a time width necessary for the SOS sensor 18 to detect it.

FIG. 2 specifically shows the circuit configuration of the pseudo sync signal generator of this embodiment. The pseudo sync signal generator 62 inputs the sync signal 19 output from the SOS sensor 18 shown in FIG. 1 to the first flip-flop circuit 72 via the 2-input OR gate 71. Q output 7 of the first flip-flop circuit 72
3 is set to H (high) level by this. The first counter circuit 74 inputs the Q output 73 to the input terminal ENT. When the Q output 73 becomes H level, the first counter circuit 74 counts the clock signal 75 input to the clock input terminal CLK.

The first counter circuit 74 is the SOS sensor 1
8 has a function as a timer circuit for controlling the lighting so that the laser beam 14 is lit just before 8. That is, when the first counter circuit 74 counts the clock signal 75 for the time corresponding to this lighting start timing (= X−1 count), its Q output 76 becomes H level.
Change to a level. The Q output 76 is supplied to the second flip-flop circuit 78, and the Q output 79 changes to the H level at the next rising of the clock signal 75. The Q output 79 is input to the input terminal ENT of the second counter circuit 81. When the Q output 79 becomes H level, the clock signal 75 input to the clock input terminal CLK is counted.

The second counter circuit 81 counts the clock signal 75 from the lighting start timing of the laser beam 14 for the SOS sensor 18, and counts the time slightly longer than the time when the synchronization signal 19 is scheduled to be output. When (= Y count), the pseudo sync signal 64 as the Q output is changed to the H level. That is, unless the Q output 79 input to the clear terminal CLR of the second counter circuit 81 is changed to the L (low) level and the count value is cleared until then, the pseudo sync signal 64 of the H level is output. It is supplied to the 2-input OR gate 83 in the correction unit 63 for jitter correction. This or gate 8
The synchronizing signal 19 is input to the other input terminal of the OR gate 3. If there is any input, the OR gate 83
Therefore, the signal is supplied to the counter 84 every one cycle, and the correspondence relationship between the surfaces of the polygon mirror 13 is maintained.

When the sync signal 19 is not output in a certain cycle and the pseudo sync signal 64 is output instead, the pseudo sync signal 64 is also supplied to the other input terminal of the OR gate 71. To be done. As a result, the circuit after the first flip-flop circuit 72 operates to turn on the laser beam 14 immediately before the next SOS sensor 18 as if the regular synchronizing signal 19 arrives, and further during this lighting period. The H level pseudo sync signal 64 can be output when the sync signal 19 is not output. The output of the OR gate 71 is supplied not only to the first flip-flop circuit 72 but also to the inverter 86, the logic of which is inverted and supplied to the clear terminal CLR of the second flip-flop circuit 78. At the same time as resetting, the count value of the second counter circuit 81 is cleared to set them to the initial state.

The clear terminal CLR of the first flip-flop circuit 72 is adapted to receive the Q output 76 whose logic is inverted by another inverter 87, so that the first counter circuit 74 is turned on at the lighting start timing. At the stage of counting for a corresponding time, it is in a state of waiting for the next input of the sync signal 19 or the pseudo sync signal 64.

By the way, the pseudo sync signal 64 is the sync signal 1
Since it is output after confirming that 9 is not output,
The output timing is later than the output timing of the synchronization signal 19. Therefore, simply change this to synchronization signal 1
If you input to OR gate 71 instead of 9 and perform processing,
There is a possibility that an error may occur or may be sequentially accumulated to hinder the detection of the laser beam 14 of the SOS sensor 18. Therefore, in this embodiment, the pseudo sync signal 64 is input to the selection input terminal SEL of the selector 89 after the logic is further inverted by another inverter 88. A data latch circuit 91 is connected to one input terminal B selected by the selector 89 and has a predetermined value D.
Is stored. The value D is obtained by adding "1" to the sum of the count values of the first and second counter circuits 74 and 81, subtracting the period of the synchronization signal 19 and adding the preset time thereto. Is.

When the selector 89 selects this value D, it is supplied to the data input terminal DATA of the first counter circuit 74 as selection data 92. And gate 94
Output 95 is connected to a load terminal LD for loading the selection data 92 into the first counter circuit 74. Therefore, when the pseudo synchronization signal 64 is output, the preset value stored in the data latch circuit 91 is used as a starting point for counting, and when a relatively short time has elapsed, the first counter circuit 74 has the H level. Will output the Q output 76. On the other hand, the selector 89 selects the other input terminal A at other times. In this case, since the value "0" is selected as the selection data 92, the data is not padded.

As described above, in this embodiment, the selector 89 selects the value D, so that even if the sync signal 19 is not continuously output, these sync signals 19 are scheduled to be output. Since the pseudo synchronization signal 64 is accurately output at a time slightly later than the time of, the start time of the correction operation in the correction unit 63 is not significantly delayed. However, the frequency of the clock signal 75 used in the pseudo sync signal generator 62 of the present embodiment is an integral multiple of the time required for one scanning of the laser beam, and in the present embodiment, this magnification is 1000 times. Is set to.

FIG. 3 shows the pseudo sync signal generator of this embodiment.
It is an example of a waveform of each part. Based on this
An example of the operation of each unit will be described along with temporal transition. Same figure
(A) shows the clock signal 75. The same figure (b)
The synchronization signal 19 shown in FIG. ₁To H level
When the beam 14 (Fig. 1) is detected,
Clearing the second flip-flop circuit 78 shown in (c)
An L level signal is supplied to the terminal CLR. By this
This Q output 79 changes to L level.
The Q output 73 shown in (d) rises to the H level. Q out
When the force 73 becomes H level,
The first counter circuit 74 starts this
Start und. And when you do X-1 count,
Next rising time t of the lock signal 75₂Second pretend
The Q output 79 of the up-flop circuit 78 changes to the H level.
It

Since the output 95 of the AND gate 94 (FIG. 3 (e)) has changed to the L level at the rising time t ₂ , the first counter circuit 74 fetches the selection data 92 at this time. In this state, since the pseudo sync signal 64 shown in FIG. 3 (g) is not output, the selector 89 selects the input terminal A (FIG. 3 (f)). Therefore, the first counter circuit 74 sets the value “0” to the selection data 9
It will be taken as 2. In this state, the first flip-flop circuit 72 is reset, so that the first counter circuit 74 stops its counting.

After time t ₂ , the second counter circuit 81 starts counting in preparation for the situation where the synchronization signal 19 is not generated. However, in this example, the time t immediately after
_The synchronizing signal 19 (FIG. 3B) is output to 3. As a result, the second flip-flop circuit 78 is reset by the output of the inverter 86 and the Q output 79 (FIG. 3 (c)) becomes L level.
The level becomes the level, and the second counter circuit 81 stops counting and clears its contents. Also, the synchronization signal 1
9 occurs, the first flip-flop circuit 72 is set at this time t ₃ , and its Q output 73 (see FIG.
(D)) becomes the H level, and the first counter circuit 74 starts the X-1 count from the next rising edge of the clock signal 75, as described above, and the clock signal 75
The Q output 79 of the second flip-flop circuit 78 changes to the H level at the next rising time of the.

In this way, the Y count by the second counter circuit 81 is started from time t ₄ after the X count is performed. However, in the case of this example, the Y count is completed without detecting the synchronization signal 19 due to the occurrence of noise or the vibration of the machine. This completion time t _6, the pseudo sync signal 64 shown in FIG. 3 (g) is outputted. As a result, the selector 89 selects the input terminal B (FIG. 3 (f)). As a result, the value D stored in the data latch circuit 91 at the next rising time t ₇ of the clock signal 75 becomes the first selection data 92.
The counter circuit 74 is preset. Then, from the next rising time t ₈ of the clock signal 75, the first counter circuit 74 starts the counting operation of the X−1 count with the value D raised. This is despite the time t ₈ and starts counting the clock signal 75,
In essence, this is equivalent to counting X from time t _{5 when the} value D is reversed. As a result, even if the sync signal 19 is not continuously detected and the pseudo sync signal 64 is continuously output, the polygon mirror 13
It is possible to correct the image writing start position accurately without mistaking the reflection surface of the.

Although the laser beam is used as the light beam in the above-described embodiments, it goes without saying that an image may be scanned using a light beam having a wavelength other than this. Further, although the SOS sensor is used for detecting each scanning line in the embodiment, it is possible to dispose other sensors on the scanning line of the light beam. For example, an EOS sensor for confirming the end of scanning of the photoconductor can be used.

Further, although the photoconductor drum is used as the photoconductor in the embodiments, other photoconductors such as a photoconductor belt may be used. Furthermore, in the embodiment, the counter counts up, but it may count down. Besides, various modifications can be made to the present invention.

[0040]

As described above, according to the first aspect of the invention, the sensor output presence / absence determining means for determining whether or not the output of the light beam sensor is output for each cycle of the light beam is arranged. When there is no output, the count value correcting means is used to increment or decrement the count value of the counter by one.
Therefore, even if the light beam is interrupted or an error occurs in the detection of the light beam sensor, the count value of the counter always shows an accurate value, and which surface of the polygon mirror is used to scan the light beam. You can easily determine whether you are going. Therefore, it is possible to effectively eliminate the occurrence of jitter due to the difference in the characteristics of each surface of the polygon mirror.

According to the second aspect of the invention, SOS sensor output presence / absence determining means for determining whether or not the output of the SOS sensor is output for each cycle of the laser beam is arranged. A pseudo SOS signal is generated from the SOS signal generating means and supplied to the counter, and the count value is incremented by one. Therefore, even if the laser beam is interrupted or an error occurs in the detection of the SOS sensor, the count value of the counter always shows an accurate value, and which surface of the polygon mirror is used to scan the laser beam. It is possible to determine whether something is wrong. Therefore, it is possible to effectively eliminate the occurrence of jitter due to the difference in the characteristics of each surface of the polygon mirror. Further, since the SOS sensor is used for checking the laser beam for each cycle, there is no need to dispose a special sensor, and the device can be manufactured at low cost.

Further, according to the third aspect of the present invention, since the correction value registration means for registering the correction value of the writing position when the laser beam is written on the photosensitive member is arranged for each surface of the polygon mirror, the counter is provided. The switching of each surface of the polygon mirror can be sequentially and accurately grasped based on the count value of, and the recording start position on the photoconductor can be accurately corrected by reading the corresponding correction value from the correction value registration means. be able to.

According to the fourth aspect of the invention, as a result of confirming that the SOS sensor output is not output by the SOS sensor output presence / absence determining means, the pseudo SOS signal is output after the time when the SOS sensor output is originally output. Therefore, by subtracting the delay due to this, it is possible to determine the presence or absence of the output of the next SOS sensor, and an error occurs in the check of the presence or absence of the output of the SOS sensor after the next due to the accumulation of the delay time, It is possible to minimize the inconvenience caused in various processes based on the pseudo SOS signal.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a circuit configuration of a main part of a recording apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram specifically showing a circuit configuration of a pseudo sync signal generator of this embodiment.

FIG. 3 is various waveform charts showing an example of the waveform of each part of the pseudo sync signal generator of this embodiment.

FIG. 4 is a schematic configuration diagram showing a configuration of a main part of an example of a conventional recording apparatus.

FIG. 5 is an explanatory diagram showing a state in which a fluctuation jitter occurs in an image on a photoconductor in a main scanning direction.

FIG. 6 is an explanatory diagram showing a first pixel arrangement state of each scanning line in which jitter is corrected.

FIG. 7 is a block diagram showing a conventionally proposed jitter correction circuit.

[Explanation of symbols]

11 ... Semiconductor laser, 13 ... Polygon mirror, 14 ... Laser beam, 16 ... Photosensitive drum (photoconductor), 61 ... Horizontal synchronization processing section, 62 ... Pseudo synchronization signal generating section, 63 ... Correction section, 64 ... Pseudo synchronization signal , 74 ... First counter circuit,
81 ... Second counter circuit, 84 ... Counter, 89 ... Selector, 91 ... Data latch circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical indication H04N 1/113

Claims (4)

[Claims] 1. A photoconductor for forming an image for recording, a polygon mirror for periodically scanning a light beam from one end of the photoconductor to the other end, and a light beam scanning path. A light beam sensor for detecting the scanning timing for each cycle; a counter for counting the detection output of the light beam sensor to identify the scanning surface of the polygon mirror; A sensor output presence / absence determining unit that determines whether or not the output of the light beam sensor is output for each cycle, and the count value of the counter is incremented by 1 each time there is a cycle in which the detection output of the light beam sensor is not output. A recording apparatus comprising: a count value correcting unit. 2. A photosensitive member for forming an image for recording, a polygon mirror for periodically scanning a laser beam from one end of the photosensitive member to the other end, and Is further arranged on the scanning start side of the laser beam to detect the scanning timing of the laser beam for each cycle, and the detection output of this SOS sensor is counted to specify the scanning surface of the polygon mirror. A counter for determining whether or not the output of the SOS sensor is output for each cycle of the laser beam, and an SOS sensor output presence / absence determining unit, and when there is a cycle in which the detection output of the SOS sensor is not output, it is pseudo. A recording device, comprising: a pseudo SOS signal generating means for generating an output of an SOS sensor and supplying the output to the counter. 3. A photoconductor for forming an image for recording, a polygon mirror for periodically scanning a laser beam from one end to the other end of the photoconductor, Is further arranged on the scanning start side of the laser beam to detect the scanning timing of the laser beam for each cycle, and the detection output of this SOS sensor is counted to specify the scanning surface of the polygon mirror. A counter for determining whether or not the output of the SOS sensor is output for each cycle of the laser beam, and an SOS sensor output presence / absence determining unit, and when there is a cycle in which the detection output of the SOS sensor is not output, it is pseudo. Pseudo SOS signal generating means for producing an output of the SOS sensor and supplying it to the counter, and a laser beam on the photoconductor for each surface of the polygon mirror. Correction value registration means for registering the correction value of the writing position when writing is performed, and a correction value registration means for reading the correction value corresponding to the surface specified by the counter from the correction value registration means. A recording apparatus comprising: an embedded position correction unit. 4. A photoconductor for forming an image for recording, a polygon mirror for periodically scanning a laser beam from one end of the photoconductor to the other end, and the one end of the photoconductor. Is further arranged on the scanning start side of the laser beam to detect the scanning timing of the laser beam for each cycle, and the detection output of this SOS sensor is counted to specify the scanning surface of the polygon mirror. A counter for determining whether or not the output of the SOS sensor is output for each cycle of the laser beam, and an SOS sensor output presence / absence determining unit, and when there is a cycle in which the detection output of the SOS sensor is not output, it is pseudo. Pseudo SOS signal generating means for generating the output of the SOS sensor and supplying it to the counter, and the pseudo SOS signal generating means for simulating the SOS sensor. When the output is created, the SOS sensor output presence / absence determination time adjusting means for subtracting the delay required for the determination by the SOS sensor output presence / absence determining means to determine the presence / absence of the output of the next SOS sensor. A recording device characterized by.