JPH05176131A - Scanning image recorder - Google Patents

Abstract

PURPOSE:To prevent black data of an attention picture element from being deviated and to approximate the data to the theoretical dot diameter of one picture element. CONSTITUTION:When a peripheral picture element recognizing circuit of a laser power switching signal generation part M recognizes that the attention picture element is the black data and eight picture elements around the attention picture element are white data, a switching signal is outputted to a laser power generation part G so as to decrease the level of laser power on the upper, lower, right and left sides. Therefore, the laser spot diameter corresponding to the picture elements of the upper, lower, right and left white data is reduced, and the black data of the attention picture element is approximated to the theoretical dot diameter of one picture element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms an image on a photoconductor by the power of laser light modulated by an image signal,
The present invention also relates to a scanning image recording apparatus using a positive development method using a positive latent image, which has a pixel density control unit for adjusting pixel density.

[0002]

2. Description of the Related Art In a positive development method using a positive latent image, the irradiation point of laser light is white. Therefore, the diameter of the laser spot is usually larger than one theoretical pixel, and white data continues for several lines. In this case, black stripes due to toner are prevented from being generated between the lines.

A scanning type image recording apparatus using the above-described positive development method using a positive latent image will be described below with reference to FIG. FIG. 3 is a block diagram showing a schematic configuration.

First, in the analog image signal generator A, C
An analog image signal read by an image sensor such as a CD (charge-coupled device)
The signal is A / D (analog / digital) converted, and further compared in the binarization processing section C with the reference level generated in the reference level generating section D of the reading section, and is supplied to the laser signal modulating section F as a 1-bit image signal. Reportedly. Further, a laser O for controlling ON / OFF of a laser LD such as a semiconductor laser
The N / OFF signal is transmitted from the laser ON / OFF signal generator E to the laser signal modulator F, and at this time, the laser ON / OFF signal is transmitted.
If the OFF signal is ON, the signal modulated by the 1-bit image signal from the binarization processing unit C is transmitted to the laser power generation unit G in the laser signal modulation unit F and emitted from the laser LD at this timing. The generated laser light passes through the laser scanning unit H including a polygon mirror and the like, and the photoconductor I
Is irradiated.

[0005]

In the printing of the conventional scanning type image recording apparatus using the positive development method using the positive latent image, as shown in FIG. 4, the pixel of interest is changed to χ (k pixels in the main scanning direction). Eye; n-1 line in the sub-scanning direction),
The target pixel χ and surrounding pixels (k-1 to k + in the main scanning direction)
1; Consider a pattern by cutting out a 3 × 3 region of (n−2 to n) in the sub-scanning direction. Here, a description will be given with reference to FIG. 4 using a pixel pattern in which the target pixel χ is black data and eight surrounding pixels are white data.

FIG. 5 shows the energy level of the laser beam
FIG. 5 is an explanatory diagram showing a relationship between (charge level) and a white data spot diameter. If the energy level is equal to or lower than e, it becomes the toner adhesion level and the spot diameter of white data is also determined by this level.

FIG. 6 shows that the energy level shown in FIG.
It is the above charge level distribution chart and the actual print chart.

FIG. 6A is a laser spot diagram by a positive development method using a positive latent image when χ = black and eight peripheral pixels are white in the case where there is no power control.

FIG. 6B shows the actual printing dot diameter of the target pixel because the spot diameter of the surrounding white data is larger than one pixel theoretically in the state at the time of actual marking in the case of FIG. 6A. Becomes smaller. In particular, in the extreme case where the resolution is 400 DPI level, there is a problem that black data may not be printed.

An object of the present invention is to provide a scanning type image recording apparatus which can solve the problems of the prior art, prevent the black data of a target pixel from being blurred, and make the dot diameter close to a theoretical dot diameter of one pixel. To do.

[0011]

In order to achieve the above-mentioned object, the scanning image recording apparatus of the present invention has an analog image signal generating section for generating an analog image signal and an analog image signal for converting the analog image signal into a digital image signal. An analog / digital conversion unit, a binarization processing unit that binarizes a digital image signal at a predetermined reference level to obtain a binarized image signal, and a pixel data memory unit that holds the data of the binarized image signal. A laser ON / OFF signal generator for turning the laser ON / OFF, a laser signal modulator for modulating the laser ON / OFF signal with the binary image signal of the pixel data memory, and a pixel data memory A laser power switching signal generating section for generating a signal for switching laser power for adjusting the pixel density by means of the above, a modulation signal of the laser signal modulating section and a laser power switching signal A laser power generating unit for emitting a more lasers, is scanned with a laser beam to the photosensitive member, and is obtained by construction of a laser scanning unit for exposing the photosensitive member.

[0012]

With the above structure, the data of the target pixel and the surrounding pixels are recognized, and when the data of the target pixel is black and the surrounding 8 pixels are white data, the laser power of the upper, lower, left and right of the target pixel is switched among the surrounding 8 pixels. Thus, by suppressing the exposure of the image of interest on the photoconductor, the black data of the pixel of interest can be made close to the theoretical dot diameter of one pixel.

[0013]

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

FIG. 1 is a block diagram showing a schematic structure of an embodiment of the present invention, and FIG. 2 is a block diagram showing a concrete structure of FIG. 1 and 2, members corresponding to the members described with reference to FIG. 3 are designated by the same reference numerals.

In the figure, A is an image sensor such as a CCD, an analog image signal generating section for receiving a signal from the timing circuit K to generate an image signal, and B is an analog / digital converting section including an A / D converter. , C is a binarization processing unit equipped with a digital comparator, D is a reference level generating unit that generates a reference digital value, E is a laser ON / OFF signal generating unit that outputs an ON signal in a printing state, and F is a logic circuit. , G is a transistor Tr and a laser power amplifier O which is an operational amplifier.
A laser power generation unit having P1 and an output switching switch SW1, H is a laser scanning unit including a polygon mirror, I is a known photosensitive member, J is a pixel data memory unit having a plurality of memories 1 to 3, M is a laser power switching signal generation unit including a peripheral pixel recognition circuit, LD is a laser that emits laser light such as a semiconductor laser, and r is a resistor.

Next, the operation of the above embodiment will be described. As shown in FIG. 4, when the target pixel is χ (kth pixel in the main scanning direction; the (n-1) th line in the sub-scanning direction), the target pixel χ and surrounding pixels (main scanning, k-1 to k + 1) Consider a pattern by cutting out a 3 × 3 region of sub-scanning, n−2 to n).

A timing signal for the read image sensor is generated from the timing circuit K, the timing signal is input to the analog image signal generating section A, and is read by the image sensor or the like at this timing on the nth line, and The k-th analog image signal is A / D converted by the analog / digital conversion unit B and 4 to 8 per pixel.
It is converted to a digital value of about bits. Further, the converted digital signal is compared with the reference digital value by the reference level generating unit D in the reading circuit in the binarization processing unit C and in the digital comparator, and the obtained 1-bit image signal (n line; kth) output Are input to the pixel data memory unit J. The pixel data memory unit J stores the data of the previous line (n-1th line), the previous previous line (n-2th line), and the data up to the current pixel (n line; kth) of the previous line. ing.

Further, when a laser ON signal is output from the laser ON / OFF signal generator E which becomes an ON signal in the printing state and is input to the laser signal modulator F, the pixel data memory J outputs (n-1th line). When the 8 pixels around the pixel of interest are white data, the pixels are the upper, lower, left, and right pixels (n-2; k), (n); n; k), (n-1; k
-1), (n-1; k + 1), a switching signal for switching the power of the laser power generator G is output and input to the laser power generator G. At the same time, the data corresponding to the upper, lower, left, and right pixels is input from the pixel data memory section J to the laser signal modulation section F, and the modulated signal modulated by the upper, lower, left, and right pixel data of the target pixel is supplied from the laser signal modulation section F. , To the laser power generator G.

In the laser power generator G, the laser LD emits light in synchronization with the input modulation signal. Further, the output level of the laser power amplifier OP1 is controlled by the SW1 in the laser power generation section G by the switching signal inputted in the pixel data memory section J.

The laser light emitted from the controlled laser LD exposes and scans the photosensitive member I at the laser scanning portion H formed by a polygon mirror or the like.

Points improved by the above embodiment will be described with reference to FIG.

FIG. 6 (c) is an explanatory view of the spot diameter under the above-mentioned control, in which a small white data spot diameter is formed by lowering the laser power levels of the vertical and horizontal directions of the target pixel. There is.

FIG. 6 (d) is an explanatory diagram of the actual printing state in the case of FIG. 6 (c), in which the black data of the target pixel is theoretically a dot of one pixel by lowering the power in the vertical and horizontal directions. You can see that it is close to the diameter.

[0024]

According to the present invention, when the target pixel is black data, the surrounding pixels are recognized from the contents of the surrounding pixel data in the pixel data memory, etc., and as a result, when the surrounding 8 pixels are all white data. By lowering the power levels of the pixels on the upper, lower, left and right sides of the target pixel, it is possible to prevent the black data of the target pixel from being blurred and to make actual printing close to the theoretical one dot diameter.

As described above, by controlling and switching the density of the pixel of interest according to the data information of the pixel of interest and the surrounding pixels, it is possible to bring each printed diagram close to the ideal printed dot pattern. It is possible to provide a scanning image recording apparatus that is effective in scanning image recording using the positive development method using a latent image.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a scanning image recording apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration of the embodiment shown in FIG.

FIG. 3 is a block diagram showing a schematic configuration of a conventional scanning image recording apparatus.

FIG. 4 is a pattern diagram of 3 × 3 clipping centering on a pixel of interest.

FIG. 5 is an explanatory diagram showing a relationship between an energy level and a white data spot diameter.

FIG. 6 is an explanatory diagram of a laser spot diameter when a target pixel is black and an explanatory diagram of actual printing.

[Explanation of symbols]

A ... Analog image signal generating section, B ... Analog / digital converting section, C ... Binarization processing section, D ... Reference level generating section, E ... Laser ON / OFF signal generating section, F ... Laser signal modulating section, G ... Laser power generating section, H ... Laser scanning section, I ... Photoconductor, J ... Pixel data memory section,
K ... Timing circuit, LD ... Laser, M ... Laser power switching signal generator.

Claims (1)

[Claims] 1. An analog image signal generator for generating an analog image signal, an analog / digital converter for converting the analog image signal into a digital image signal, and a digital image signal binarized at a predetermined reference level to obtain 2 A binarization processing unit that obtains a binarized image signal, a reference level generation unit that generates the reference level, a pixel data memory unit that holds the data of the binarized image signal, and a laser for turning ON / OFF the laser. A laser ON / OFF signal generator, a laser signal modulator that modulates the laser ON / OFF signal with the binary image signal of the pixel data memory, and the pixel data memory to adjust the target pixel density , A laser power switching signal generator that generates a signal for switching the laser power of the surrounding pixels, and a modulation signal of the laser signal modulator and a laser power switching signal. 1. A scanning image recording apparatus comprising: a laser power generation unit that emits light from a laser; and a laser scanning unit that scans the photosensitive member with laser light and exposes the photosensitive member.