JPH0431221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to an image recording device, and more particularly to an image recording device in a plane scanning photographic transmission device that records and reproduces image signals including halftones.

[Prior art]

The image recording device in the conventional plane scanning type photoelectric transmission device has a one-to-one correspondence between the sub-scanning and the main scanning, and one scan is made for each movement of the recording medium for one scanning line.
Performing main scan.

For main scanning, the scanning light is deflected using a scan mirror that reciprocates in the case of low speed, and a rotating polygon mirror in the case of high speed.

Scanning by a scan mirror is normally performed at a scanning speed during main scanning and at high speed during return within a time corresponding to the invalid screen width. Therefore, it takes time to suppress transient vibrations during high-speed return, and it can only be used for low-speed scanning at speeds equivalent to 150 revolutions per minute or less.

On the other hand, a rotating polygon mirror rotates in one direction and generally has excellent stability at high speeds, but because it performs main scanning for the number of mirror surfaces in one rotation, it is not necessarily suitable for low-speed scanning at the equivalent of 150 revolutions per minute. However, rotational stability cannot be achieved.

That is, the conventional image recording apparatus has the disadvantage that it cannot be realized with the same structure from low speed to high speed.

[Purpose of the invention]

An object of the present invention is to provide an image recording device that can be realized with the same structure from low speed to high speed.

That is, an object of the present invention is to eliminate the above-mentioned drawbacks by performing main scanning N (a positive integer of N≧2) times for each sub-scanning, and converting the image signal to be recorded into N-bit multi-value signals for each pixel. By dividing the light intensity of the scanning light corresponding to each bit of the same order of the decomposed pixel data and recording and scanning each scanning line N times, a reproduced halftone image is obtained based on the storage effect of the recording medium. An object of the present invention is to provide an image recording device that can realize high speeds with the same structure.

[Structure of the invention]

The image recording apparatus of the present invention includes a recording scanning means that performs main scanning N (a positive integer of N≧2) times for each sub-scanning of one scanning line, and a recording and scanning means that performs main scanning N (a positive integer of N≧2) times, and a signal that converts an image signal including halftones into a signal for each pixel. Analog-to-digital converting means decomposes the pixel data into N bits according to the level and outputs each pixel data, and one side alternately writes the pixel data for one scanning line every sub-scan, and the other side writes the pixel data for one scanning line. a pair of storage means for reading the pixel data corresponding to the scanning line preceding the scanning line read out N times for each main scan; The image forming apparatus includes a density signal generating means for outputting recording signals, and a switching means for switching the recording signal according to the main scanning.

[Explanation of Examples]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. , a pair of memories 4
1 and 42, and a read control circuit 5.
, a density signal generation circuit 6 including eight recording signal generators 61 to 68, a switch circuit 7, a timing control circuit 8, and a drive amplifier circuit 9.

The operation of the embodiment shown in FIG. 1 will be explained in detail below with reference to FIGS. 2 and 3. 2 is a perspective view of the recording scanning section shown in FIG. 1, and FIG. 3 is a time chart for explaining the operation of the storage circuit shown in FIG. 1.

As shown in FIG. 2, the recording scanning unit 1 deflects a laser beam from a laser light source 11 such as a helium neon laser using an optical modulator 12. The optical modulator 12 is, for example, an optical modulator that utilizes an acousto-optic effect, and can deflect the laser beam according to the frequency of the ultrasonic drive power supplied from the drive amplifier circuit 9 shown in FIG.

The laser beam deflected by the optical modulator 12 passes through the slit 13 and irradiates the mirror surface of the rotating polygon mirror 14.

When the recording signal RD is not supplied to the drive amplifier circuit 9 (that is, in the initial state), the laser beam deflected according to the frequency of the drive power from the drive amplifier circuit 9 is set to pass through the slit 13. When the recording signal RD is supplied to the drive amplifier circuit 9, the frequency of the drive power changes according to the level of the recording signal RD, and the deflection angle of the laser beam changes. Therefore, the amount of laser beam passing through the slit 13 changes depending on the level of the recording signal RD.

The rotating polygon mirror 14 has a plurality of reflective surfaces fixed around a rotation axis so as to form a regular polygonal prism, and usually has a hexahedron, an octahedron, or the like. The rotating polygon mirror 14 is rotated at a constant speed in the rotation direction A by a synchronous motor 15 directly connected to the rotating shaft, and the period in which the N reflective surfaces rotate is equal to the period of one main scan of the transmitter (that is, the period of the phase signal PH). period). Therefore, during one main scanning period of the transmitting device, the recording scanning section 1
performs main scanning N times.

The reflected laser beam from the rotating polygon mirror 14 is Fθ
A scanning light spot of a predetermined beam diameter is formed on the photosensitive recording paper 21 by the lens 16, and is deflected as the reflecting surface rotates to perform main scanning recording on the photosensitive recording paper 21.

An optical sensor 20 is arranged at the main scanning start position of the laser beam formed by each reflecting surface, and a scanning start timing signal is sent every time the main scanning of each reflecting surface starts.
Generates SP.

The photosensitive recording paper 21 is fed by a pair of feeding rollers 17,1.
The feeding roller 18 is rotated in the rotational direction B by the rotation of the step motor 19, and fed out in the sub-scanning direction C. The feeding length of the photosensitive recording paper 21 is set to a length corresponding to the scanning line width for each phase signal PH.

Next, as shown in FIG. 1, the image signal PX including halftones from the transmitter is supplied to the A/D conversion circuit 2. In the following explanation, the case of "N=8" will be described.

The A/D conversion circuit 2 has a determination level that divides the voltage value for the white level into an upper limit reference voltage and the voltage value for the black level as a lower limit reference voltage, and divides the voltage between the two voltages into 256 steps. 8-bit digitally encoded pixel data ED is outputted according to the amplitude level set to the determination level, and is supplied to the write control circuit 3.

On the other hand, the timing control circuit 8 outputs a write timing signal WE whose level is alternately converted to "1" and "0" for each phase signal PH, and the write control circuit 3
supply to.

As shown in FIG. 3, the write control circuit 3 alternately writes pixel data in scanning line units to the memory 41 of the storage circuit 4 when the write timing signal WE is "0" and to the memory 42 when it is "1". Write ED.

The write timing signal WE is supplied to the read control circuit 5, and when the write timing signal WE is "1", the memory 41 is in the read state, and when the write timing signal WE is "0", the memory 42 is in the read state. Furthermore, as shown in FIG. 3, the timing control circuit 8 generates a read timing signal RE which is generated every scan start timing signal SP supplied from the recording scanning section 1 and continues until the corresponding reflective surface finishes main scanning. is output and supplied to the readout control circuit 5 to read out the pixel data ED from either the memory 41 or the memory 42 in the readout state.

Each read pixel data is 8 bits.
The ED is supplied to the recording signal generators 61, . . . , 68 of the density signal generating circuit 6 for each bit of the same order.

The recording signal generators 61, .
When the input bit value is "1", a recording signal RD of a predetermined level is outputted and supplied to the switch circuit 7.

Here, the predetermined level is when the relative output level from the recording signal generator 61 is "1", the relative output level from the recording signal generator 62 is "1/2", and the relative output level from the recording signal generator 63 is "1/2". Level is "1/4"
The recording signal generator 6
The relative output level from 8 is set to be "1/128".

The switch circuit 7 sequentially switches the recording signal RD for each main scan according to the read timing signal RE from the timing control circuit 8 and supplies it to the drive amplifier circuit 9.

The drive amplifier circuit 9 supplies the optical modulator 12 with drive power having a frequency according to the amplitude level of the recording signal RD, and deflects the laser beam. Therefore, by accumulating recording energy in the recording medium through eight main scans, recordings with densities corresponding to 256 levels for each pixel data ED are reproduced.

However, the value of "N" is determined according to the required gradation reproduction performance, and the larger "N" is, the higher the gradation reproduction performance becomes.

〔Effect of the invention〕

As described below, the image recording device of the present invention has N
By adding a bit analog-to-digital conversion means, a pair of storage means, a density signal generation means, and a switching means, main scanning is performed N times for each sub-scanning,
Each main scan is performed using scanning light whose light intensity is divided corresponding to each bit of the same bit of the pixel data obtained by decomposing the image signal to be recorded into N bits into multi-value for each pixel. Obtaining a reproduced image has the effect of providing versatility because it can be realized using a stable scanning mechanism with the same structure from low speed to high speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Figure 2 is a perspective view of the recording scanning section shown in Figure 1;
The figure is a time chart for explaining the operation of the memory circuit shown in FIG. In the figure, 1... recording scanning section, 2... A/D
Conversion circuit, 3...Write control circuit, 4...Storage circuit, 41, 42...Memory, 5...Read control circuit, 6...Concentration signal generation circuit, 61, -, 68...
...recording signal generator, 7...switch circuit, 8...
Timing control circuit.

Claims (1)

[Claims] 1. Recording scanning means that performs main scanning N (a positive integer of N≧2) times for each sub-scanning of one scanning line, and image signals including halftones according to the signal level of each pixel.
Analog-to-digital converting means that decomposes into multivalued bits and outputs each pixel data, and one side alternately writes the pixel data for one scanning line for each sub-scanning and the other side converts the pixel data to the written scanning line. a pair of storage means for reading the pixel data corresponding to the scanning line preceding the scanning line N times for each main scan; and N records each having a predetermined amplitude level for each bit of the same order in the read pixel data. An image recording apparatus comprising: density signal generating means for outputting a signal; and switching means for switching the recording signal according to the main scanning.