JPH0556253A - Image reduction recording device - Google Patents

Abstract

PURPOSE:To perform the image reduction picture quality deterioration hardly causing by performing the reduction with a reduction ratio R and outputting to a recording forming means after the inputted image is converted to an N-fold resolution. CONSTITUTION:A MODEM 11 demodulates an image signal inputted from a line, a code restoring device 12 restores the coded data to original image data, and the data are stored in an image memory 13. After a picture element density converter 14 converts the image data into an N-fold resolution, reduction is performed with a reduction ratio R. Based on the converted data, a laser unit 15 emits a laser beam to a photosensitive drum 16, the latent image is formed, and by a toner, a clear image is recorded on the recording paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reduction recording apparatus for reducing and recording an image.

[0002]

2. Description of the Related Art In a facsimile apparatus or the like, image reduction recording is performed such that, for example, when a transmitting side transmits a B4 size document, the receiving side converts it into an A4 size and prints it out. Image reduction methods include an optical reduction method and a method of quantizing image data and thinning pixels. Recently, laser printers have been adopted,
In this case, a method of quantizing image data and thinning it out is used.

FIG. 5 shows an example of the configuration of a facsimile machine having a laser printer. The image data received via the public line is demodulated by the modem 11, the encoded data is restored by the code restorer 12, and the reducer 17 performs reduction processing by thinning out pixels according to the size of the receiving side, and the image memory 13
Accumulate in. The laser unit 15 sequentially reads out image data from the image memory 13 and forms a latent image on the photosensitive drum 16 with a laser beam, visualizes this latent image with toner and prints it out.

FIG. 6 is a diagram for explaining the reduction processing in the reduction device 17. The original image for one line shows the state before reduction,
The image after reduction shows the result of reducing the original image at a reduction ratio R = 3/4. In the reduction method, one pixel out of four pixels is thinned out to three pixels. In this case, pixel 2 among pixels 1 to 4 is thinned out.

[0005]

When the pixel thinning method as described above is used to reduce the size, the image quality is deteriorated due to the loss of information. In the above example, the information of white, black, white, and black is changed to the information of white, white, and black. As long as the thinning method is adopted, such a loss of information cannot be avoided.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image reduction recording apparatus in which image quality deterioration is unlikely to occur.

[0007]

FIG. 1 shows the principle of the present invention. In the figure, 1 is an image input means for inputting image data, 3 is a recording forming means having a resolution N times the resolution of the input image data, and 2 is the image input means 1.
This is an image density conversion means for inputting more image data, converting it to N times the resolution, reducing it at a reduction ratio R and outputting it to the recording forming means 3.

Further, the N is made larger than the reciprocal of the R.

Further, the image density converting means 2 is an image memory for storing the image data, and the pixel density conversion for sequentially reading the image data from the image memory to convert it into N times the resolution and then reducing it at a reduction rate R. Composed of vessels.

[0010]

The resolution of the recording forming means 3 is set to N times the resolution of the input image data, the input image data is first set to N times, and thinning corresponding to the reduction ratio R is performed. As a result, the information lost by thinning is reduced compared to the case of thinning without multiplying N times.

Further, by setting the multiple N of the resolution to be larger than the reciprocal of the reduction ratio R, it is possible to prevent the loss of information due to thinning.

Further, a buffer memory is required between the image input means 1 and the recording forming means 3 in order to adjust the processing speed. However, by providing the image memory upstream of the pixel density converter, the image memory has N memory. Since the data before multiplication is stored, the capacity can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the configuration of this embodiment.
In the figure, 11 is a modem that demodulates a signal input from the line, 12 is compressed data of image data to be transmitted in order to reduce transmission data, and the encoded data is transmitted. A code restorer for restoring the original image data, 13 an image memory for storing the restored image data, and 14 for multiplying the resolution of the input image data by N times in order to match the resolution of a laser unit 15 which will be described later, with a reduction rate R. A pixel density converter 15 for reduction is a laser unit, and emits a laser beam based on the data converted into the resolution data of the laser unit 15 by the pixel density converter 14. A photosensitive drum 16 is irradiated with a laser beam onto the drum to form a latent image, and a toner image is recorded on the recording paper.

FIG. 3 shows a state in which the photosensitive drum 16 records on a recording sheet with toner. Recording is performed for each main scanning line in the direction perpendicular to the paper feed direction.

FIG. 4 is a diagram for explaining the operation of the pixel density converter 14. The original image of one line shows a state of being read from the image memory 13. In this embodiment, the original image has a resolution of 200 dpi (dot per inch, 200 / 25.4 = 7.
8 lines / mm), and the resolution of the laser optical unit is 400 dpi and N = 400/200 = 2. Further, the reduction ratio R = 3/4.

In the image after the interpolation operation, each pixel is doubled, and the number of the interpolated pixel is shown by enclosing it with a circle. The image after the reduction operation shows a state in which one pixel is thinned out from four consecutive pixels. In this case, white, white, black, and black are white, white, and black. It can be white, black, or black. In any case, the information of white 1 and black 2 of the original picture becomes white 1, white, black 2 or white 1, black 2, black,
The information of white and black does not change. As a result, no information is lost.

The relationship of N = 2> 1 / R = 4/3 is established. If N <1 / R, information may be lost. When N = 1 / R, there is almost no risk of missing, but for safety, N> 1 / R is adopted.

In FIG. 2, the image memory 13 is provided on the upstream side of the pixel density converter 14. If this is provided downstream of the reducer 17 as shown in FIG. 5, the pixel density conversion rate becomes, for example, 2
In that case, assuming that the total number of pixels of the original image is n, the capacity of the page memory for 2n pixels, which is twice the total number of pixels, is required, which is very wasteful in terms of cost.

[0019]

As is apparent from the above description, according to the present invention, the recording and forming means having a resolution N times the resolution of the original image is provided, and the original image is multiplied N times and thinned and reduced.
Information loss can be reduced. If the relationship of N> 1 / R is satisfied, information loss can be prevented.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram showing a configuration of an example.

FIG. 3 is an explanatory diagram of a recording image forming scanning method in laser recording.

FIG. 4 is a diagram illustrating pixel density conversion at the time of reduction in the main scanning direction according to the present exemplary embodiment.

FIG. 5 is a block diagram showing a configuration of a facsimile having a conventional laser recording device.

FIG. 6 is a diagram for explaining pixel density conversion at the time of reduction in the main scanning direction by a conventional method.

[Explanation of symbols]

 11 Modem 12 Code restorer 13 Image memory 14 Pixel density converter 15 Laser unit 16 Photosensitive drum

Claims (3)

[Claims] 1. An image input means (1) for inputting image data, a recording forming means (3) having a resolution N times the resolution of the input image data, and image data from the image input means (1). And an image density converting means (2) for converting the image into a resolution of N times and reducing it at a reduction rate R and outputting it to the recording forming means (3). 2. The image reduction recording apparatus according to claim 1, wherein the N is set to be larger than the reciprocal of the R. 3. The image density conversion means (2), an image memory for storing the image data, and a pixel for sequentially reading the image data from the image memory, converting the image data to N times the resolution, and then reducing the pixel at a reduction rate R. The image reduction recording apparatus according to claim 1 or 2, wherein the image reduction recording apparatus comprises a density converter.