JPS5897960A - Scanner - Google Patents

Abstract

PURPOSE:To eliminate jitter due to an angle error of a rotary polygon mirror, by starting storing a readout signal in response to the scan starting pulse of each surface of the rotary polygon mirror, and then start reading the stored signal in response to the scan starting pulse of a following surface. CONSTITUTION:Light emitted from a scanning light source 2 is made incident to a rotary polygon mirror 1 to make a scan on an original 12. Reflected light from the original 12 is made incident to a photoelectric converting element 31, whose output is inputted as a picture signal to a delay circuit 6. A photosensor 41 is provided at the end part where the scan on the original 12 is started, and generates an output pulse when the reflected light from the rotary polygon mirror 1 is made incident. The output pulse is generated when the scan on the polygon mirror is started. The picture signal obtained by the scanning is written in the line memory of the delay circuit 6 and read when a scan starting pulse corresponding to a following surface is inputted. Then, an angle error of the polygon mirror is eliminated to improve the picture quality.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning device, and particularly to a scanning device in a high-speed and high-precision image input device that deflects scanning light using a rotating polygon mirror.

In a conventional scanning device, light from a scanning light source is incident on a rotating polygon mirror in which a plurality of plane mirrors are arranged adjacent to each other around a rotation axis, and the light from the scanning light source is transmitted by rotating the rotating polygon mirror at a rapid speed. The document surface is scanned by deflecting light, and the reflected light from the document surface is photoelectrically converted to obtain a calligraphy signal.

On the other hand, a scanning start pulse generator provided in front of the scanning start position of the document surface receives the light beams deflected corresponding to each surface of the rotating polygon mirror, so that the light beams are deflected corresponding to the respective surfaces of the rotating polygon mirror. generating a data start pulse that is repeated at every predetermined scanning time in response to a scanning start time, and generating the data start pulse corresponding to each surface before the document image signal obtained corresponding to each surface; It is inserted to obtain a data output signal.

In such a conventional scanning device, if there is a division angle error for each surface of the rotating polygon mirror, the time interval between the rise time υ of the data start pulse and the start time of the document signal corresponding to each surface is This will change in proportion to the division angle error for each surface, and this time difference will cause a jitter in the scanning device.

Furthermore, it is extremely difficult to achieve a high degree of precision in dividing angle errors of a rotating polygon mirror within a few seconds due to the processing technology involved.

In other words, conventional scanning devices have the drawback that the time from the rise of the data start pulse corresponding to each surface to the scanning start time fluctuates in response to the division angle error of each surface, resulting in jitter. Yes, nine.

The purpose of the present invention is to eliminate the above-mentioned drawbacks and improve image quality by suppressing temporal fluctuations between the rise of the data start pulse and the scan start time corresponding to each surface, making it possible to ignore the occurrence of jitter. An object of the present invention is to provide a scanning device tt which is capable of scanning.

The scanning device of the present invention includes a rotating polygon mirror in which a plurality of plane mirrors are arranged adjacent to each other around a rotation axis, and a scanning device that scans a document surface by being incident on the rotating polygon mirror and deflected by the rotation of the rotating polygon mirror. a scanning light source, a photoelectric conversion circuit for photoelectrically converting the reflected source from the document surface and outputting a calligraphic signal; a scan start pulse generating section that generates a scan start pulse in response; and a data start pulse that is generated after a predetermined time elapses after the generation of one of the scan start pulses and is repeated at the predetermined time intervals thereafter. A data start pulse generation circuit that generates a data start pulse, starts storing the calligraphy signal generated corresponding to each side with a scan start pulse corresponding to each side, and transfers the stored calligraphy signal to the next side of each side. and a delay circuit for starting reading at the data start pulse corresponding to the data start pulse and outputting a corrected document image signal.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

A scanning device flii shown in FIG. 1, a six-sided plane mirror Ml, ~
.

A rotating polygon mirror 1 with M6t, a scanning light source 2, a photoelectric conversion circuit 3 including a photoelectric conversion element 31 and a photocurrent amplifier 32, a scanning start node including an optical sensor 41, a slit 42, and a time width setting circuit 43. It is configured to include a generating section 4, a data start pulse generating circuit 5, and a delay circuit 6.

Below, the operation of the scanning device shown in FIG. 1 will be explained in detail with reference to FIGS. 2 to 5. 82 is a waveform diagram for explaining the operation in the embodiment shown in FIG. 1, and FIG.
4 is a detailed block diagram of the data start pulse generation circuit in the embodiment shown in FIG. 1, and FIG. 5 is a detailed block diagram of the delay circuit in the embodiment shown in FIG. 1. This is a professional drawing.

The rotation of the rotating polygon mirror IFi is controlled by the synchronous clock output from the synchronous clock generation circuit 7, and the motor power supply 8
A rotating shaft is connected to a synchronous electric motor 810 that is supplied with driving power from the synchronous motor 810, and synchronously rotates counterclockwise at a first period Tl.

The focused light emitted from the scanning light source 2 is incident on the rotating polygon mirror 1, which has a structure in which six plane mirrors Mt and -7M6 are arranged adjacent to each other around the rotation axis, and is reflected by the rotation of the rotating polygon mirror l. The reflected light from the plane mirror passes through the FQ lens 11 and scans the scanning surface of the original 12. The reflected light from the original 12 is incident on the photoelectric conversion element 31 of the photoelectric conversion circuit 3,
The signal is converted into an electrical signal corresponding to the density of the original 12, amplified by the photocurrent amplifier 32, and a calligraphy signal a is output. Further, the original 12 is held between feed rollers 13 and 13' and fed out in the direction of arrow F, and sub-scanning is performed.

On the other hand, the optical sensor 41 and the slit 42 of the scan start pulse generator 4 are provided in front of the scan start position of the document, and as shown in FIG. When passing through the slit 42, the light source 4
1 to @2 The scanning start position t pulse xfi=generated as shown in FIG. Here, the scan start position pulse for each surface of the scan start position pulse X, X X 1. /-, X IB are plane mirrors M1. ~． This corresponds to the scanning start position of M6.

The scan start position pulse X is supplied to a time width setting circuit 43, and a scan start pulse b having a pulse time width P is output. The pulse time width P is an integral multiple of the period of the clock $2, and is set to a value of 1% or less of a second period Tz, which will be described later. However, the clock $2 is generated by the synchronous clock generation circuit 7 and is set to a value at least twice the maximum image signal frequency.

Next, as shown in FIG. 4, the data start pulse generation circuit 5 has a preset switch 851, a counter 51,
Plip-flop F51. F52.degree.

+5V is applied from terminal B to the data of F51, F51, and plane mirror M of scan start pulse B.
Corresponds to 1 - A scan start pulse b1 is flip-flop, pu F5
When the black terminal of 1 is supplied to the terminal CK, the flip-flop
The output terminal Q of the flip-flop F51 is not "high", and the data input 77D of the flip-flop F52 is "high". The clock S2 is connected to the clock terminal CK of the flip-flop F52.
is being supplied, the flip-flop F52 is set at the rising edge of the next clock s2 when the data output becomes "high", and the output terminal Q becomes "high", and one input of the AND circuit 54 becomes "high", and the data input of the 7-lip flop F53 is "low", so it is free.
Since the output terminal Qtfir of the flop F53 is "high," another input of the AND circuit 54 is also "high."
The logical product is taken, the output of the logical product circuit 54 becomes "high", and the load terminal LD of the counter 51 becomes "high".

51 on the counter is the aforementioned first period Tl'? : Divide by the number of faces of rotating polygon mirror 1, 6. Period T2 of critical condition 2 and clock sZ
11'' is subtracted from the quotient N of the period 1N-t''. It is set in advance by the preset switch 851, and when the load terminal LD becomes "high", the clock 52t-counting starts.

When the force t7fiK5 th"N-1' glue a and glue ml are counted, the phase pulse C2't- corresponding to the plane @M2 is output from the output terminal CO.
), a clock whose phase is inverted by the phase inversion circuit 55 is supplied to the terminals CKVCu/a and I*2), and after the phase pulse C2' is supplied and the data input becomes "high". The flip-flop F53 is set by the rising clock. Therefore, when the output terminal Q of F53 becomes "low", one input of the AND circuit 54 becomes "low".
Therefore, the output of the AND circuit 54 becomes "low", and 51 is set to the initial value of the counter.

Therefore, the output terminal CO of the counter 51 becomes "low", the data output of the flop F53 becomes "low" and the output terminal Q becomes "no", and all of the AND circuits 54 When the input is "Noi", the clock 51 restarts the counting of the clock Iz.

In this way, each time the counter 51 counts 1N-1'' blacks, a phase pulse is generated from the counter 51, and this operation is repeated until the scanning is completed. The phase pulse c 2 /→c 3
/ ~ C6' → cl' in order, @ N 1 of the terminal 82
Phase pulses C' are obtained which are sequentially output with a second period T2 corresponding to one phase pulse. The preset value t-@N-1'' of 51 is set in the counter in order to compensate for the delay caused by one black and one black in the flip-flop F52°F1a.

The phase pulse C' is supplied to a time width setting circuit 56, which outputs a data start signal C having a pulse time width P'.The pulse time width P' is an integral multiple of the period of the clock S2 and The period T is set to a value of 01% or less.

Here, as shown in FIG. 2, a scan start pulse b2 corresponding to each surface is applied. , l) 6 and the data start pulses C2, . This is something that occurs due to.

Next, as shown in FIG. 5, the delay circuit 6 includes a write counter W61, a write address switching circuit W62, a % read counter R61, a read address switching circuit R62,
2 line memories M 61. MB2, analog-to-digital conversion circuit 63, and digital-to-analog conversion circuit 64
It is equipped with

The analog-to-digital conversion circuit 63 receives the supplied drawing signal a.
After sampling at t-clock S3, it is converted into a digital signal. The clock I3 is generated by the periodic clock generation circuit 7, and "n-s!=s3 (where n>1 is an integer)"
is set to

The write counter W61 receives the supplied scanning start pulse bK.
It is activated at the falling edge of the scan start pulse bl corresponding to the included plane mirror M1, stores the digital output signal of the drawing signal a1 corresponding to the plane mirror M1 in the line memory M61 at clock S3, and writes the writing signal a1 to the write counter W61fl. It is set to the initial value upon termination. Next, when a scanning start pulse b2 corresponding to the plane mirror M2 is supplied,
The write address switching circuit W62 designates the line memory M62 for writing, the write counter W61 is activated at the falling edge of the scan start pulse b2, and the plane @! The digital signal of the drawing signal a2 corresponding to M2 is stored in the line memo IJM62, and upon completion of writing the digital signal of the drawing signal a2, the write counter W61 is set to the initial value.

On the other hand, the data start pulse C is supplied to the read counter R61 and the read rare address switching circuit R62.
When the data start pulse C2 corresponding to the plane mirror M2 is supplied, the read address switching circuit R62 switches the line memory M
The read counter R61 is activated at the falling edge of the data start pulse c2, and the line memory M61 is read out.
When the reading of the digital signal t-a of the drawing signal a1 stored in is completed, the reading counter R61 is set to the initial value.

The read digital signal of the drawing signal a1 is supplied to the digital-to-analog conversion circuit 64, where it is converted into an analog signal, and the drawing signal a1/ corresponding to the plane mirror MIK of the corrected drawing signal d shown in FIG. 2 is output.

Therefore, the drawing signal al' corresponding to the plane mirror M1 of the corrected drawing signal d becomes a ratio signal delayed by the second cycle T2 compared to the original drawing signal a1.

Next, when the data start pulse C3 corresponding to the plane mirror M3 is supplied, the read address switching circuit R62 specifies reading from the line memory M62, and the read counter R61 is activated at the falling edge of the data start pulse C3 to read out the line memory M62. The drawing signal a! stored in M62! digital signal t-
The read digital signal is supplied to a digital-to-analog conversion circuit 64 and converted into an analog signal.
Calligraphy signal a2 corresponding to plane mirror M2 of corrected calligraphy signal d
/ is obtained. As shown in FIG. 2, this calligraphy signal a 2 / is delayed compared to the original calligraphy signal a2 by a time subtracted from the second period Tz by a time t2f corresponding to the division angle error of the plane mirror M2 based on the plane mirror Mlt. The signal becomes
The division angle error becomes a corrected signal.

In this way, signals corresponding to each side of the digitized calligraphy signal a are alternately written into the line memory M61° MB2 from the falling edge of the scan start pulse b for each side, and the stored signals are transferred to each side. The data are read out alternately from the falling edge of the data start pulse C corresponding to the next side, and the read digital signals are converted into analog to obtain the corrected document image signal d shown in FIG. Therefore, the modified calligraphy signal d
The scanning start time of the calligraphy signal corresponding to each stroke has the same cycle as the second cycle Tz of the data start signal C.

The clock generated by the synchronous clock generation circuit 7, ri s2. s
3 is synchronized with the synchronization clock s1, and is set to more than twice the maximum image signal frequency in order to reduce the influence of jitter equivalent to one clock.

Next, the corrected drawing signal d is supplied to the buffer circuit 9, and inserted into the separately supplied data start pulse C1-corrected drawing signal d, and the division angle error of each surface of the rotating polygon mirror 1 shown in FIG. A data output signal C with corrected data is obtained.

As explained above, in the embodiment of the present invention, the number of surfaces of the rotating polygon mirror is six in h, but the same effect can be obtained with any number of surfaces as long as it is three or more.

In addition, in the embodiment, the calligraphy and drawing signals are digitally converted and stored,
The read digital signal is converted into an analog signal to obtain a corrected document/picture signal, but it is also possible to handle it as an analog signal by using a COD analog memory or the like without performing such conversion.

As described above, the scanning device of the present invention adds a delay circuit to store the document and image signals generated corresponding to each surface of the rotating polygon mirror using the scan start pulses generated in accordance with the scan start timing of each surface. Scanning of each surface, which occurs due to the division angle error of each surface of the rotating polygon mirror, is avoided by starting reading out the stored calligraphy signal with a periodic data start pulse corresponding to the next surface. This has the effect of improving image quality by suppressing temporal fluctuations in the start time and making it possible to ignore the occurrence of ivy.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, a detailed waveform diagram explaining the operation in the embodiment shown in wc2 and Ifi@1, and FIG. 3 is a section A in the embodiment shown in FIG. 4 is a detailed block diagram of the data start pulse generation circuit in the embodiment shown in FIG. 1, and FIG. 5 is a detailed block diagram of the delay circuit in the embodiment shown in FIG. In the figure, 1... rotating polygon mirror, 2... scanning light source, 3... photoelectric conversion circuit, 4......
Scan start pulse generation section, 5... Data start pulse generation circuit, 6... Delay circuit, 7...
Synchronous clock generation circuit, 8...Motor power supply, 9
...Buffer circuit, 12...Manuscript, 4
1... Optical sensor, 42... Pickpocket, To,
a...Documentation signal, b...Scanning start pulse, C...Data start pulse, d...
Corrected drawing signal, e...Data output signal. Figure 4 Figure 5

Claims (1)

[Claims] ! a rotating/rotating polygonal bell in which 11 plane mirrors are arranged adjacent to a rotation axis; a scanning light source that enters the rotating polygonal mirror and is deflected by the rotation of the rotating polygonal mirror to scan the document surface; A photoelectric conversion circuit that photoelectrically converts light reflected from the document surface and outputs a writing signal, and a photoelectric conversion circuit that is provided in front of the scanning start position of the document surface and the rotation multiplier f@! a scan start pulse generator that generates a scan start pulse in response to each summer scan start time; a data start pulse generation circuit that generates a data start pulse that is repeated in a row; and a data start pulse generation circuit that starts storing the document signal generated corresponding to each side with a scan start pulse corresponding to each side, and stores the stored document signal. A scanning device comprising: a delay circuit that starts reading at the data start pulse corresponding to the next side of each side and outputs a corrected document image signal.