JP2001296725A - Writing optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a writing optical device capable of receiving an inputted image as on the condition of data resolution, improving the quality of an outputted image by the action of a writing optical system and realizing simplification and reduction of the cost without changing the previous constitution of the device at all. SOLUTION: This optical device is installed in an image forming device for printing and outputting the inputted image and is equipped with the writing optical system forming a latent image by exposing a photoreceptor while scanning it by a flickering light source based on an inputted image signal. The writing optical system is provided with a correction means for correcting a printed image by forming a main latent image by irradiating the photoreceptor with ordinary writing light by a main light source and forming a sub latent image around the main latent image by using a sub light source different from the main light source with respect to the inputted image signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in an image forming apparatus such as a digital copying machine / fax / printer which prints out an input image and, when printing, blinks according to input image data. The present invention relates to a writing optical device that emits light with a light source and forms an electronic latent image on a photosensitive member while scanning.

[0002]

2. Description of the Related Art In an image forming apparatus such as a digital copying machine, a facsimile, a laser printer, or the like, if an input image is output at the same resolution, an output image in which diagonal jaggies and the like are conspicuous in some cases. . In the case of a copier, the input image refers to an output image after performing a predetermined process on a document, and in the case of a facsimile, an output image after performing a predetermined process on a received image. To tell.

In order to solve this problem, an output image with an increased resolution is usually formed on an input image and printing is performed, so that an output image is formed so that oblique lines and the like can be seen more smoothly. is there. Hereinafter, the input resolution is referred to as a data resolution, and the output resolution is referred to as a print resolution.

For example, in an image processing apparatus disclosed in Japanese Patent Application Laid-Open No. 4-16060, a binary image is scaled (enlarged), filtered on an enlarged image, and binarized again by a predetermined threshold value. The formed image is formed. That is, by enlarging and printing the input image at the magnification of the print resolution / data resolution, an output image can be formed in which the jaggies of oblique lines are more smoothly corrected than the input image. .

In the contour correction device disclosed in Japanese Patent Application Laid-Open No. 6-6598, a mechanism for analyzing the state of image data is provided, and the focus of the writing light is controlled in accordance with the state. A smooth latent image corresponding to the image is formed to improve the image quality.

[0006]

However, in the conventional writing optical device, in order to form an output image with a higher resolution than the input image, it is necessary to provide a processing path for the output image. The device for printing also needs to operate at the printing resolution.

For example, for an apparatus having a printing resolution of 2x and 2y, an input image having a resolution in the main scanning direction x and a subscanning direction y is enlarged twice in the main scanning direction and twice in the subscanning direction. Processing for performing doubling, processing for performing binarization by performing a filtering process on the doubling, and the like are required, and a processing circuit and a memory for holding image information during calculation are required.

In a printing apparatus, the printing resolution in the main scanning direction is doubled, and the number of lines in the sub-scanning direction is also two.
Therefore, it is necessary to blink at four times the speed if the printing speed is maintained. The writing optical system in the writing optical device is an LSU (Laser Scanning Unit).
) Can be realized by blinking the light source at four times the cycle and doubling the rotation speed of the polygon mirror or doubling the number of mirror surfaces. On the other hand, when an LED lamp array is used as a writing optical system in a writing optical device, it becomes necessary to double the number of light emitting elements in the main scanning direction.

However, naturally, there is a problem that a printing apparatus which operates at a higher speed has a higher cost.

[0010] Further, speeding up and control on the side of sending data to the printing apparatus are also required, and there is a problem that the apparatus becomes complicated.

Further, in the contour correction device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-6598, it is not necessary to double the data resolution itself, but it is still necessary to provide a light source control mechanism according to the transition state of the image. And it is becoming more complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to receive an input image at the same data resolution without changing the configuration before the present apparatus at all, and to operate the writing optical system. It is an object of the present invention to provide a writing optical device capable of improving the image quality of an output image and simplifying the device and reducing the cost.

[0013]

In order to solve the above-mentioned problems, a writing optical device according to the present invention is provided in an image forming apparatus for printing and outputting an input image, and blinks based on an input image signal. In a writing optical device having a writing optical system for exposing a photoconductor while scanning with a light source to form a latent image, the writing optical system includes a normal photoconductor for an input image signal. Correction means is provided for irradiating a beam spot larger than the writing light to form a sub-latent image around the main latent image by the writing light to the normal photoconductor, thereby correcting the printing image. It is characterized by having. In the present invention, the writing optical system means hardware for writing to the photoconductor, while the writing optical device means a broad concept including software.

According to the above invention, the writing optical device comprises:
The image forming apparatus is provided in an image forming apparatus that prints out and outputs an input image, and includes a writing optical system that forms a latent image by exposing a photosensitive member while scanning with a light source that blinks based on an input image signal.

The writing optical system irradiates the input image signal with a beam spot that is larger than the writing light to the normal photosensitive member, so that the writing light to the normal photosensitive member is generated. Correction means for forming a sub-latent image around the main latent image and correcting the print image is provided.

Therefore, the correction of the print image is performed on the input image signal by the correction means provided in the writing optical system.

As a result, the print quality can be improved without increasing the print resolution, which is the output resolution, beyond the data resolution, which is the input resolution, and without increasing the number of pixels.

That is, in the present invention, the input image data is directly input to the light source without any image processing before the present apparatus. Then, the correction unit provided in the writing optical system from the light source corrects the print image with respect to the input image signal.

Therefore, since the resolution input to the writing optical device remains the data resolution, the printing quality can be improved without considering the problem of increasing the speed of the writing optical device. Further, the image quality can be improved by combining with a conventional writing optical device.

Further, the correcting means is formed in a writing optical system for exposing the photosensitive member to form a latent image while scanning with a light source which blinks based on the input image signal, so that the correcting means is compact. The structure is also simple.

The correcting means irradiates the input image signal with a beam spot which is larger than the writing light to the normal photosensitive member, so that the main latent light by the writing light to the normal photosensitive member is applied. A sub-latent image is formed around the image to correct the print image.

That is, the contour correction device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-6598 is similar in that correction is performed by a writing optical system without depending on an image processing system. But,
In Japanese Patent Application Laid-Open No. 6-6598, a beam spot of writing light to a normal photoconductor is irradiated, whereas in the present invention, a beam spot larger than writing light to a normal photoconductor is irradiated. Is different.

Further, this makes it possible to employ various means such as a transmittance changing means in front of a rotating mirror, which will be described later, to form a sub-latent image, thereby performing a smoothing process.

As a result, the input image is received at the same data resolution without any change in the configuration prior to the present apparatus, the image quality of the output image is improved by the operation of the writing optical system, and the apparatus is simplified and the cost is reduced. Can be provided.

According to a second aspect of the present invention, there is provided a writing optical device according to the above-described writing optical device, wherein the correcting means comprises a light source which transmits light from a light source to a rotating mirror for scanning. Characterized in that it is provided with a transmittance changing means in front of the rotary mirror for changing the transmittance.

According to the above invention, the correcting means includes the transmittance changing means in front of the rotating mirror for changing the transmittance of the optical path from the light source to the rotating mirror for performing scanning.

Therefore, the transmittance changing means before the rotating mirror is:
The print image is corrected by changing the transmittance of the optical path incident on the rotating mirror for scanning from the light source.

As a result, the correcting means can be formed only by inserting a filter for changing the transmittance of the optical path before the rotating mirror, for example, as the transmittance changing means before the rotating mirror.

Therefore, the input image is received at the data resolution without changing the configuration before this device at all.
It is possible to provide a writing optical device that can improve the image quality of an output image by the operation of the writing optical system, and can surely simplify the device and reduce the cost.

According to another aspect of the present invention, there is provided a writing optical device, wherein the correcting means includes a rotating mirror surface for changing a reflectance of a mirror surface of the rotating mirror for performing scanning. It is characterized by having a reflectance changing means.

According to the above invention, the correcting means includes the rotating mirror reflectance changing means for changing the reflectance of the mirror surface of the rotating mirror for scanning.

Therefore, the rotating mirror reflectivity varying means includes:
The print image is corrected by changing the reflectance of the mirror surface of the rotating mirror for scanning.

For this reason, as the rotating mirror surface reflectance changing means, for example, only by processing the rotating mirror surface of the rotating mirror,
Correction means can be formed.

Therefore, the input image is received at the data resolution without any change in the configuration before the present apparatus.
It is possible to provide a writing optical device that can improve the image quality of an output image by the operation of the writing optical system, and can surely simplify the device and reduce the cost.

According to a second aspect of the present invention, in the above-described writing optical apparatus, the correcting means includes a rotating mirror of the rotating mirror in an optical path from the rotating mirror for performing scanning to the photosensitive member. The present invention is characterized in that a rotating mirror reflected light transmittance changing means for changing the transmittance of the reflected light is provided.

According to the above invention, the correcting means includes the rotating mirror reflected light varying means for varying the reflected light of the rotating mirror in the optical path from the rotating mirror to the photosensitive member for performing scanning.

Therefore, the rotating mirror reflected light variation means corrects the print image by varying the reflected light of the rotating mirror in the optical path from the rotating mirror to the photosensitive member for scanning.

For this reason, the rotating mirror reflected light varying means is provided with an optical effect at the final stage, for example, coating the final turning mirror, and does not require installation accuracy.

Further, processing is easy. In addition, f-θ
Since the light has passed through the lens system, light at all angles with respect to the main scanning direction is at a constant speed, and distortion of the optical path due to processing hardly occurs.

Therefore, the input image is received at the data resolution without any change in the configuration before the present apparatus.
It is possible to provide a writing optical device that can improve the image quality of an output image by the operation of the writing optical system, and can surely simplify the device and reduce the cost.

In order to solve the above-mentioned problems, in the writing optical device according to the present invention, in the writing optical device described above, the correction means may be configured to rewrite the reflected light when the writing exposure is reflected from the photoreceptor. A re-imaging means for forming an image on a body is provided.

According to the above invention, the correction means includes the re-imaging means for forming the reflected light when the writing exposure is reflected from the photoreceptor on the photoreceptor again.

For this reason, the re-imaging means reflects the reflected light when the writing exposure is reflected from the photoreceptor by, for example, a mirror provided near the photoreceptor and forms an image on the photoreceptor again. Thus, the print image is corrected.

As a result, it is possible to correct the print image without changing the configuration of the conventional writing optical device at all. In addition, since the light has passed through the f-θ lens system, the light at all angles with respect to the main scanning direction has a constant velocity, and distortion of the optical path due to processing hardly occurs.

Therefore, the input image is received at the data resolution without changing the configuration before this device at all.
It is possible to provide a writing optical device that can improve the image quality of an output image by the operation of the writing optical system, and can surely simplify the device and reduce the cost.

According to another aspect of the present invention, there is provided a writing optical device provided in an image forming apparatus that prints out an input image and scans the image with a light source that blinks based on the input image signal. In a writing optical device having a writing optical system for exposing a photosensitive member to form a latent image while exposing the photosensitive member, the writing optical system supplies a general light source to a normal photosensitive member with a main light source in response to an input image signal. Correction means for irradiating the writing light to form a main latent image, and forming a sub-latent image around the main latent image with a sub-light source different from the main light source to correct a print image is provided. It is characterized by being provided.

According to the above invention, the writing optical system includes:
The main light source irradiates the input image signal with writing light to a normal photoreceptor to form a main latent image, and surrounds the main latent image with a sub-image different from the main light source. Correction means for forming a sub-latent image with a light source and correcting a print image is provided.

For this reason, it is possible to correct the print image without changing the configuration of the writing optical system other than the light source at all. In addition, since the sub latent image is formed by the sub light source to correct the print image, the smoothing process can be performed by adjusting the sub latent image by the sub light source.

As a result, the input image is received at the data resolution without any change in the configuration prior to the present apparatus, the image quality of the output image is improved by the operation of the writing optical system, and the apparatus is simplified and the cost is reduced. Can be provided.

According to the writing optical device of the present invention, in order to solve the above-mentioned problems, in the writing optical device described above, the correcting means turns on a plurality of sub-light sources based on a plurality of line information to perform printing. Is provided with a plurality of line lighting means for performing the smoothing process.

According to the above invention, the correction means includes a plurality of line lighting means for performing a printing smoothing process by lighting a plurality of sub light sources based on a plurality of line information.

For this reason, the plural line lighting means performs a printing smoothing process by lighting a plurality of sub light sources based on a plurality of line information, thereby correcting a print image.

Therefore, since each sub light source is turned on based on the information of a plurality of lines to form a sub latent image, a smoothing process can be performed more accurately and more accurately.

In order to solve the above-mentioned problems, the writing optical device of the present invention is characterized in that, in the writing optical device described above, the multi-line lighting means calculates information of the preceding and following lines and information of the corresponding line to specify the line. It is characterized in that a specific portion sub beam generating means for generating a latent image on the photoreceptor by a beam of each sub light source only in a portion is provided.

According to the above-mentioned invention, there is provided a specific portion sub-beam generating means for calculating the information of the preceding and succeeding lines and the information of the corresponding line, and generating a latent image on the photosensitive member only by the beam of each sub light source at the specific portion. .

Therefore, the specific portion sub-beam generating means calculates the information of the preceding and following lines and the information of the corresponding line,
A latent image is generated on the photoconductor only by a beam of each sub light source at a specific portion.

For this reason, by controlling the light emission of each sub light source to a specific portion with reference to the target line and the pixel information before and after the target line, a high-quality image can be obtained more accurately.

Further, in order to solve the above-mentioned problems, the writing optical device of the present invention, in the above-described writing optical device, determines a portion corresponding to an edge of an image, and determines the length and length of the portion corresponding to the edge. In addition to the edge determining means for obtaining the shape, the multi-line lighting means generates the latent image by the sub-beam in an interpolative manner based on the length and shape of the portion corresponding to the edge by the edge determining means.

According to the above-mentioned invention, the edge determining means includes:
The part corresponding to the edge of the image is determined, and the length and shape of the part corresponding to the edge are obtained. The plural-line lighting unit generates a latent image by a sub-beam in an interpolative manner based on the length and shape of a portion corresponding to an edge determined by the edge determining unit.

For this reason, it is possible to detect a step in a line having a shallow angle by the edge judging means, so that it is possible to control the generation of an interpolation pixel according to the angle, that is, the length of the edge. In particular, since the oblique lines having a small angle are appropriately subjected to the smoothing process, a smoother image can be reproduced.

In order to solve the above-mentioned problems, the writing optical device according to the present invention is characterized in that, in the writing optical device described above, the edge determining means detects the edge line and the length of the edge as a method of detecting the edge and the edge length. The edge state is determined based on the pixel information of the preceding and following lines, and the comparison of the edge information is performed from both ends of the line in the main scanning direction to obtain the position of the edge and the length of the edge. I have.

[0062] According to the above invention, the edge determination means:
As a method of detecting the edge and the length of the edge, the edge state is determined based on the pixel information of the line of interest and the lines before and after the line of interest, and this edge information is compared from both ends of the line in the main scanning direction. And the length of the edge are determined.

Therefore, as a method of edge detection and edge length, an edge is detected by comparing pixels of peripheral lines, and the edge information is detected from both ends of the line in the main scanning direction. , The position and length of the edge of the edge can be determined. For this reason, a hardware configuration can be realized by using a line memory, so that an inexpensive configuration can be realized.

In order to solve the above-mentioned problem, the writing optical device according to the present invention, in the above-described writing optical device, comprises: a correcting unit that arranges a light source whose effective printing pixel number blinks according to an input image signal; It is characterized in that light from the light source is collectively written line by line on a photosensitive member for forming a latent image.

According to the above invention, the correction means arranges the light sources whose effective print pixels blink in accordance with the input image signal, and collects the light from this light source on the photosensitive member for each line to form a latent image. Write to.

For this reason, even in a small device in which it is difficult to install the LSU, it is possible to correct the print image using a light source such as an LED lamp array.

Therefore, it is possible to provide a writing optical device which receives an input image as it is at the data resolution, improves the image quality of the output image by the operation of the writing optical system, and can simplify the device and reduce the cost. .

[0068]

[Embodiment 1] An embodiment of the present invention will be described with reference to FIGS.
It is as follows.

In an image forming apparatus such as a digital copying machine or a printer according to the present embodiment, when printing image data, similarly to a general digital copying machine or the like, a writing optical device exposes a photosensitive member to writing light from a writing optical device. Is done. Here, the photoreceptor is uniformly charged before the exposure operation. It is also assumed that the photoconductor can sufficiently hold the applied charge.

When the photoreceptor is exposed, only the exposed portion is deprived of electric charge, and the potential of the portion becomes lower than that of the non-exposed portion. This potential difference varies depending on the characteristics of the photoconductor, the amount of exposure to be given, the time, and the size of the area. If an image formed by the fluctuation of the potential formed on the photoreceptor, that is, the distribution of the electric charge is defined as an electrostatic latent image, the toner in the developing device adheres to the photoreceptor according to the potential state of the photoreceptor. I do.

Thus, a toner image is formed on the photosensitive member. The photoconductor contacts the printing paper while holding the toner image. It should be noted that there is also a case where the vehicle only approaches. At this time, the toner image is transferred to the printing paper by generating an attractive force from the back of the printing paper that is stronger than the electrostatic attraction with respect to the toner. Next, the toner image formed on the printing paper is fixed on the printing paper using heat or the like.
Through the above steps, the image data is taken out as a printed matter.

Here, a general operation for forming an electrostatic latent image will be described in detail.

First, an image to be created is a grid having a certain resolution, each point having density information, and forming an image as a whole. That is, an image is assembled from a set of pixels, and the smaller the unit pixel, the greater the amount of information. Also, each unit pixel has density information, and depending on the image, has either color information, multi-tone black and white or two-tone black and white information.

Normally, in a printing system for forming a color image, image data is stored in, for example, CMYK (cyan, magenta,
(Yellow / Black) in general, and processing is performed for each color.

Also in the present embodiment, pixel data input to the writing optical device is assumed to be multi-tone or two-tone having information necessary for forming one color.
Also, the resolution is defined as the interval between the pixels, and for example, 600 pixels per inch (= 2.54 cm) is referred to as 600 dpi (= 236 dpi). Further, when handling an image, the direction in which the writing exposure is scanned is defined as the main scanning direction, and the direction orthogonal thereto is defined as the sub-scanning direction. In other words, in forming an image, the direction in which the photosensitive member and the printing paper are sequentially fed corresponds to the sub-scanning direction.

Next, the writing optical device blinks the light source,
Exposure in the main scanning line direction of the photoconductor can be performed by making the light incident on a rotating mirror called a polygon mirror. At this time, the angle between the optical path from the light source and the mirror surface changes due to the rotation of the polygon mirror,
Usually, one line of main scanning is exposed to the photoconductor by one surface of the mirror body.

When one line is exposed, the photosensitive member moves in the sub-scanning direction by one line, that is, by one pixel. By repeating this operation, the pixel data is correctly exposed in the main scanning direction and in the sub-scanning direction, and an electrostatic latent image is formed on the photoconductor.

The blinking signal of the light source is formed in units of pixel information of one line in the main scanning, and is input to the writing optical device. At this time, the writing resolution in the main scanning direction is determined by the lighting timing given to one pixel signal and the pitch between pixels actually formed on the photoconductor. Also,
The writing resolution in the sub-scanning direction is determined by the interval between the main scanning lines of the electrostatic latent image, that is, the moving speed of the photoconductor.

Here, for example, the data resolution of the image data input to the writing optical device is the main scanning data resolution Rim and the sub-scanning data resolution Ris, and the resolution of the latent image written on the photoconductor is the main scanning writing resolution. Consider a writing optical device that has Rom and the sub-scanning writing resolution Ros. The rotational speed of the polygon mirror when Rim = Rom and Ris = Ros is Sp1, and the moving speed of the photoconductor is Sd1. Note that this condition indicates that the image data and the writing latent image have an equal magnification relationship.

In the above writing optical device, for example,
To double the latent image resolution in the main scanning direction, it is necessary to double the number of input pixels in the main scanning direction. At that time, if the rotation speed of the polygon mirror is kept at Sp1, the blinking timing of the light source needs to be doubled. At this time, the lighting time per pixel is 1
/ 2.

On the other hand, in order to double the latent image resolution in the main scanning direction without changing the blinking timing of the light source, it is necessary to reduce the rotation speed of the polygon mirror to 、 and to expose one line. Since the time is doubled, the moving speed of the photoconductor must also be halved.

Next, in order to double the resolution of the latent image in the sub-scanning direction, it is necessary to double the number of input pixels in the sub-scanning direction, that is, the number of lines. At this time, if the rotation speed of the polygon mirror is kept at Sp1, the moving speed of the photoconductor must be reduced by half.

In order to double the latent image resolution in the sub-scanning direction without changing the moving speed of the photosensitive member, it is necessary to make the blink timing of the light source double the speed, The rotation speed of the mirror also needs to be doubled.

Next, if the resolution of the latent image in the main scanning direction and the resolution of the latent image in the sub-scanning direction are both doubled, the number of input main scanning and sub-scanning pixels must be doubled. As a result,
The data amount is quadrupled. At that time, if the rotation speed of the polygon mirror is kept at Sp1, the blinking timing of the light source needs to be doubled, and the moving speed of the photoconductor must be reduced to half.

When the blinking timing of the light source is not changed, the rotation speed of the polygon mirror needs to be halved, and the moving speed of the photoconductor must be halved.

Further, when the moving speed of the photosensitive member is not changed, it is necessary to make the blinking timing of the light source four times as fast and double the rotation speed of the polygon mirror.

In each of the above cases, it is necessary to provide sufficient exposure so that the latent image can be visualized. Therefore, depending on the respective operating conditions, the pre-charging of the photoconductor, the light emitting state of the light source, the state of the developing device, etc. Must be managed. Further, increasing the resolution of the latent image requires preprocessing the input image data, increasing the data, and sending the data at the timing described above.

However, in the writing optical device of the present embodiment, the resolution of the latent image can be increased without changing the data resolution. Specifically, by providing various correction means for correcting a print image in a writing optical system without performing intermediate processing such as provision of an interpolation pixel and resolution interpolation on an input image signal, the appearance of the image signal is improved. It increases the resolution.

As a result, the input data does not need to be pre-processed, and the input operation does not involve a shift. Therefore, the image quality can be reduced by merely replacing the writing optical system with the conventional writing optical device. Can be improved.

The writing optical device of the present embodiment having the above-described writing optical system will be described in detail.

First, the writing optical device has one laser diode, which is a blinkable writing optical system, and uses this as a light source. This light source is capable of emitting and not emitting light sufficiently following the input signal cycle and a change in the signal. The light from the light source passes through a slit provided on the front surface of the light source, and reaches the photoreceptor by a cylindrical lens through a light beam having the specified beam diameter and the following light path.

That is, the light from the light source is used for scanning.
First, the light enters a rotating polygon mirror. The reflected light passes through the f-θ lens so as to be incident at the same angular velocity on the arrival line of the photoconductor, and arrives at the same pixel pitch between both ends and the center in the main scanning direction of the photoconductor latent image. . In addition, mirrors for turning light back,
A sensor for capturing a light emission signal for synchronization, an optical path to the sensor, and the like are included. These are usually unitized to form an LS as a writing optical device.
U (Laser Scanning Unit).

Next, the writing optical device of this embodiment is
Various correction means for correcting the print image can be adopted, and will be described below in order.

As a first correcting means, a filter such as a filter having a transmittance of 1 at the center in the optical path incident on the polygon mirror and having a transmittance decreasing toward the peripheral portion is used. Is added. This filter functions as the transmittance changing means before the rotating mirror of the present invention.

At this time, as shown in FIGS. 2 (a) and 2 (b), the latent image and the visible image formed on the photosensitive member through the writing optical system and the optical path are the same as those of a normal unit when they are independent points. In order to obtain the same visible image size as that of the above, the size of the beam spot is assumed to be larger than usual in a focused state.

As a result, in the case of a portion represented by a plurality of points, as shown in FIGS. 1A and 1B, even in a portion which is not visible at an isolated point, FIGS. As described above, in a latent image formed by a plurality of dots, a potential level that can be sufficiently visualized is newly generated, a visualized image is generated by interpolation with respect to a normal visualized image, and a smoother image expression than before is generated. be able to.

The above operation will be described in detail.

First, as shown in FIG. 3A, the spot size generated as a latent image on a photosensitive member by a light source in a conventional writing optical device is approximately one pixel. However, in the writing optical device of the present embodiment, as shown in FIG. 3B, the photosensitive member is exposed with a larger spot size.

At this time, in the optical path from the light source to the photosensitive member, for example, a filter is provided as a writing optical system having an effect of reducing the light transmittance from the center to the periphery.

As a result, the latent image on the photosensitive member becomes as shown in FIG. That is, since the transmittance at the periphery is reduced, the light amount is large at the center but small at the periphery. At this time, the potential distribution of the photoreceptor is changed as shown in FIG.
When the relationship is as shown in FIG. 3B, the print image is higher than the visual potential, and the actual print image is as shown in FIG. 3C.

Although the above example describes the case where a single point is printed, for example, when print data including a plurality of points as shown in FIG. In the embodiment, since a filter having an effect of reducing the light transmittance from the center to the periphery is provided, the latent image is as shown in FIG. 4B, and the actual print image is
The result is as shown in FIG.

On the other hand, in the ordinary writing optical system which does not pass through the above-mentioned filter, the print image is shown in FIG.
The result is as shown in FIG. Therefore, it can be seen that the print image shown in FIG. 4D is smoothed as compared with the print image shown in FIG. 4C.

The following configuration as the correction means is shown in FIG.
As shown in (1), processing is performed on the mirror surface portion of the polygon mirror 10, which is a rotating mirror as a writing optical system, such that the reflectance decreases as the beam spot moves up and down from the line 10a passing therethrough. The processed polygon mirror 10 functions as a rotating mirror reflectance changing means of the present invention.

As a result, FIGS. 5B, 5C, and 5D
As shown in (e), the latent image is a normal polygon mirror 1
At 0, a smoother image expression is obtained than when a latent image is formed. Further, as compared with the above-described correction means in which a filter as a writing optical system is added in the optical path, the effect can be obtained only by replacing the mirror.

The following configuration as the correction means is, for example, a normal mirror surface at the center line where the beam spot scans with respect to the final folding mirror as a writing optical system located immediately above the photosensitive member. Mirror finishing is performed so that the reflectance decreases as the distance increases. Specifically, for example, coating is performed. The mirror-finished final turning mirror functions as a rotating mirror reflected light varying means of the present invention.

Thus, a smooth image expression can be obtained.

In this correction means, the size of the final turning mirror is large because it is close to the final position of the optical path, and since it is a plane mirror, the reflectance decreases as it goes up and down from the line 10a. The processing is easier than in the case where the processing is performed.

In addition, since the light has passed through the f-θ lens system, the light at all angles with respect to the main scanning direction has a constant velocity, and the optical path distortion due to the processing hardly occurs.

A further configuration as a correction means is shown in FIG.
As shown in (a), since the light incident on the photoconductor 1 is reflected on the surface of the photoconductor 1, this reflected light is again reflected.
Mirrors 11 as a writing optical system for condensing light on the photoconductor 1 are arranged between the LSU 2 and the photoconductor 1.

Thus, a smooth image can be similarly formed by the latent image formed by the exposure from the LSU 2 and the latent image formed by the reflected light. Therefore, the mirrors 11 have a function as re-imaging means of the present invention.

In this case, the effect can be obtained by using the same LSU 2 as the conventional configuration and extrapolating the mirrors 11.

As described above, the smoothing effect can be obtained for the image to be printed by giving the above-described changes in each part without changing the basic configuration from the conventional writing optical device.

When smoothing is not performed,
For example, immediately before or immediately after the turning mirror existing at the final position of the optical path from the LSU 2, for example, the ON /
A shutter mechanism that can be turned off can be provided.

As a result, it is possible to provide a correction means capable of controlling the occurrence and non-occurrence of the smoothing effect.

As another method when the smoothing is not performed, as shown in FIG. 6B, the mirrors 11 1 and 11 1 are set so that the reflected light from the photoreceptor 1 is not reflected by the mirrors 11.
1 is rotated so that no image is formed again. Thereby, normal printing can be performed.

As a result, as described above, by controlling the occurrence and non-occurrence of the smoothing effect, if there is a concern that the image quality will be impaired if the smoothing function is used, depending on the user's selection, The function is O
An image can be formed by FF.

Therefore, in the writing optical device of the present embodiment, the smoothing effect can be increased by setting the spot size of the light source sufficiently large and adjusting the light intensity (light amount) at the center and the periphery of the optical path. is there.

As described above, the writing optical device according to the present embodiment is provided in the image forming apparatus that prints out an input image, and includes one laser diode as a light source that blinks based on the input image signal. And a writing optical system for exposing the photoconductor 1 to form a latent image while scanning with the laser diode.

The writing optical system irradiates the input image signal with a beam spot that is larger than the writing light for the normal photosensitive member 1 to write on the normal photosensitive member 1. To form a sub-latent image around the main latent image by light and correct the print image,
A filter having an effect of lowering the light transmittance from the center to the periphery, or a process in which the reflectance decreases in a mirror surface portion of the polygon mirror 10 as the beam spot moves up and down from the line 10a passing therethrough,
Alternatively, the mirror mirror has a normal mirror surface at the center line where the beam spot scans with respect to the final turning mirror, and the mirror surface processing such that the reflectance decreases as the beam spot moves further outward and vertically, reflection of exposure to the surface of the photoconductor 1 The mirrors 11 and 11 for condensing light on the photoreceptor 1 again are connected to the LSU 2 and the photoreceptor 1.
And correction means such as arrangement.

Accordingly, the correction of the print image is performed on the input image signal by the correction means provided in the writing optical system.

As a result, the print quality can be improved without increasing the print resolution, which is the output resolution, beyond the data resolution, which is the input resolution, and without increasing the number of pixels.

That is, in the present embodiment, the input image data is directly input to the light source without any image processing before this apparatus. Then, the correction unit provided in the writing optical system from the light source corrects the print image with respect to the input image signal.

Therefore, since the resolution input to the writing optical device remains the data resolution, the printing quality can be improved without considering the problem of increasing the speed of the writing optical device. Further, the image quality can be improved by combining with a conventional writing optical device.

Further, the correcting means is constituted in a writing optical system for exposing the photoreceptor 1 to form a latent image while scanning with a light source which blinks based on the input image signal, so that it is compact and compact. Yes, the configuration is simple.

The correcting means irradiates the input image signal with a beam spot larger than the normal writing light to the photosensitive member 1 so that the normal writing light to the photosensitive member 1 is used. A print image is corrected by forming a sub-latent image around the main latent image.

As a result, as the formation of the sub-latent image, the above-mentioned filter having the effect of reducing the light transmittance from the center to the periphery or the line 1 through which the beam spot passes in the mirror surface portion of the polygon mirror 10 is used.
0a has a normal mirror surface at the center line where the beam spot scans, with respect to processing such that the reflectance decreases as the distance from the top to the bottom decreases, or the final turning mirror,
Reflection light of exposure to the surface of the photoreceptor 1 is mirror-processed such that the reflectance decreases as the distance from the outside and up and down is increased.
The mirrors 11 that converge light on the photoreceptor 1 are LSU2
Correction means such as arrangement between the photoconductor 1 and the photoconductor 1 can be employed, and smoothing processing can be performed.

As a result, the input image is received at the data resolution without any change in the configuration before the present device, the image quality of the output image is improved by the operation of the writing optical system, and the device is simplified and the cost is reduced. Can be provided.

In the writing optical apparatus according to the present embodiment, the correction means includes a filter as a rotating mirror reflectance changing means for changing the transmittance of an optical path from the light source to the polygon mirror 10 for performing scanning. Have.

Accordingly, the filter corrects the print image by changing the transmittance of the optical path incident on the polygon mirror 10 for performing scanning from the light source.

As a result, only the mirror surface of the polygon mirror 10 is processed as the transmittance changing means before the rotating mirror,
Correction means can be formed.

Therefore, the input image is received at the data resolution without changing the configuration before this device at all.
It is possible to provide a writing optical device that can improve the image quality of an output image by the operation of the writing optical system, and can surely simplify the device and reduce the cost.

Further, in the writing optical device of the present embodiment, the correcting means includes a rotating mirror reflectance changing means for changing the reflectance of the mirror surface of the rotating mirror for performing scanning.

Therefore, the rotating mirror reflectivity varying means is:
The print image is corrected by changing the reflectance of the mirror surface of the rotating mirror for scanning.

For this reason, the correction means can be formed only by processing the rotation mirror surface of the polygon mirror 10 as the rotation mirror reflectance changing means.

Therefore, the input image is received at the same data resolution without any change in the configuration before the writing optical device, the image quality of the output image is improved by the operation of the writing optical system, and the simplification of the device is ensured. Further, it is possible to provide a writing optical device capable of reducing cost.

Further, in the writing optical device of the present embodiment, the correcting means is a polygon mirror 10 for performing scanning.
And a rotating mirror reflected light varying means for varying the reflected light of the polygon mirror 10 in the optical path from the photoconductor 1 to the photosensitive member 1. This rotating mirror reflected light variation means has, for example, a mirror processing with respect to the final turning mirror, which has a normal mirror surface at the center line where the beam spot scans, and the reflectance decreases as the distance from the mirror further outward and vertically increases. ,In particular,
For example, coating is performed.

As a result, the rotating mirror reflected light variation means corrects the print image by varying the reflected light of the polygon mirror 10 in the optical path from the polygon mirror 10 to the photosensitive member 1 for scanning.

For this reason, the rotating mirror reflected light variation means does not require installation accuracy because it provides an optical effect at the final stage. Further, processing is easy. In addition, since the light has passed through the f-θ lens system, light at all angles with respect to the main scanning direction is at a constant speed, and distortion of the optical path due to processing hardly occurs.

Therefore, the input image is received at the same data resolution without any change in the configuration before the writing optical device, the image quality of the output image is improved by the operation of the writing optical system, and the simplification of the device is ensured. Further, it is possible to provide a writing optical device capable of reducing cost.

Further, in the writing optical device of the present embodiment, the correction means comprises mirrors 11 and 11 for imaging the reflected light when the writing exposure is reflected from the photosensitive member 1 on the photosensitive member 1 again.
It has.

For this reason, the mirrors 11 correct the print image by forming the reflected light when the writing exposure is reflected from the photoreceptor 1 on the photoreceptor 1 again.

As a result, it is possible to correct a printed image without changing the configuration of the conventional writing optical device at all. In addition, since the light has passed through the f-θ lens system, the light at all angles with respect to the main scanning direction has a constant velocity, and distortion of the optical path due to processing hardly occurs.

Therefore, the input image is received at the same data resolution without any change in the configuration before the writing optical device, the image quality of the output image is improved by the operation of the writing optical system, and the simplification of the device is ensured. Further, it is possible to provide a writing optical device capable of reducing cost.

In the present embodiment, one laser diode is used.

As a result, as in the conventional case, the number of light sources is one, and a print image can be corrected by changing the intermediate optical path.

In this embodiment, one laser diode which blinks in response to an input image signal is provided, and the light from the laser diode is scanned on the photosensitive member 1 for forming a latent image while the main scanning line is being scanned. Write to.

As a result, the operation is completed in the writing optical device without the need for processing or re-forming the image data.
Before and after that, the writing optical device can be formed without changing the conventional configuration.

In this embodiment, the beam spot diameter is controlled and the interpolation function is turned off in response to a request from the image forming apparatus.

[0149] Therefore, the data for which the image quality may be impaired by the smoothing function is reduced.
Smoothing image quality can be selectively obtained.

[Second Embodiment] The following will describe another embodiment of the present invention with reference to FIG. For the sake of convenience, members having the same functions as those shown in the drawings of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Further, it is assumed that various features of the first embodiment can be applied in combination with the present embodiment.

In the first embodiment, one laser diode is used as a light source and a laser beam larger than usual is emitted.

However, in the present embodiment, as the correction means, for example, a laser diode as a plurality of light sources is provided in the LSU 2 as a writing optical device,
The photoreceptor 1 is exposed.

More specifically, the main light source irradiates the ordinary photosensitive member with writing light to form a main latent image, and a sub light source different from the main light source is provided around the main latent image. Correction means for forming a sub-latent image and correcting a print image.

In this case, it is preferable to form an image on the photoreceptor 1 using substantially the same optical path using a half mirror or the like in order to use the light emitting optical path and thereafter in common. The above-described method of using substantially the same optical path using a half mirror or the like is generally used in an image forming apparatus such as a digital copying machine / printer or the like for high-speed operation in which two lines are written at once. It is.

Thus, two continuous lines, that is, two dots in the sub-scanning direction, are written on one surface of the polygon mirror 10.

In the present embodiment, the configuration of the correction means is used, and the optical path is adjusted so as to reach one main scanning line of the photosensitive member 1. Note that, once again, one laser is called a main light source and the other laser is called a sub light source.

At this time, when a latent image is formed on the photoreceptor 1, the main light source emits light with a beam diameter capable of forming an original resolution and an image. That is, a latent image shown by a black circle in FIGS. 5B and 5D is formed.

On the other hand, for example, when independent dots are formed, the sub light source emits an amount of light that does not cause visualization, that is, an amount of light that does not cause a potential change, and emits light with a larger beam diameter than the main light source. And That is, a latent image indicated by a cross hatch in FIGS. 5B and 5D is formed.

As a result, the exposure by the sub light source affects each other in accordance with the image to be created. Therefore, a visible region other than the portion exposed by the main light source is generated in an interpolation manner.

In the above description, the exposure by the sub light source is formed so as to overlap the main light source. However, the present invention is not limited to this.

For example, as shown in FIGS. 7 (a), (b), (c), and (d), in a sub light source for writing information of light emission by one main light source, an image is formed in the vicinity of the upper, lower, left, and right sides. An optical system can be formed in such an arrangement. At this time, as shown in FIGS. 7A and 7B, for example, in the case where independent dots are formed, the sub light source emits a light amount that does not cause visualization, that is, a light amount that does not cause a potential change. It emits light with a larger beam diameter than the main light source.

As a result, as shown in FIGS. 7 (c) and 7 (d), the exposure by the sub light source affects each other according to the image to be formed. Regions occur interpolatively.

As a result, a smoother image can be formed.

On the other hand, in the present embodiment, a latent image equivalent to that of a normal writing optical device is formed by a main light source, and a latent image generated by interpolation by a sub light source is also visualized. Although a smooth output image quality is obtained, normal image formation can be performed by not emitting light from these sub light sources, as in the first embodiment.

Thus, when there is a concern that the image quality may be impaired by using the smoothing function according to the selection by the user, the function can be turned off to form an image.

As described above, in the writing optical device of the present embodiment, the writing optical system irradiates the input image signal with the normal writing light to the photosensitive member 1 by the main light source. A correcting means for forming a main latent image, and forming a sub-latent image with a sub-light source different from the main light source to correct a print image is provided around the main latent image.

Therefore, the print image can be corrected without changing the configuration of the writing optical system other than the light source at all. In addition, since the sub latent image is formed by the sub light source to correct the print image, the smoothing process can be performed by adjusting the sub latent image by the sub light source.

As a result, the input image is received at the data resolution without any change in the configuration before the present apparatus, the image quality of the output image is improved by the operation of the writing optical system, and the apparatus is simplified and the cost is reduced. Can be provided.

Further, in the present embodiment, the size and potential characteristics of the latent image when reaching the photosensitive member 1 are different between the respective light sources, that is, the main light source and the sub light source.

For this reason, by making the potential change incidentally around the image to be developed (developed), the image becomes smooth.

In the present embodiment, the center positions of the latent images on the photosensitive member 1 can be made the same.

For this reason, by making the potential change incidentally around the image to be developed (developed), the image becomes smooth. Further, the degree of correction can be adjusted by the influence of the latent image by the main light source and the sub light source.

Further, in the present embodiment, it is possible to prevent the position of the latent image on the photosensitive member 1 from being coincident between the main light source and the sub light source.

For this reason, a higher resolution correction can be performed on the normal pixel arrangement.

In this embodiment, the operation / non-operation of the smoothing function can be switched by stopping light emission of a certain light source in response to a request from the image forming apparatus.

For this reason, it is possible to selectively obtain a smoothed image quality for data whose image quality may be impaired by the smoothing function.

[Embodiment 3] Another embodiment of the present invention will be described below with reference to FIGS. For convenience of explanation, members having the same functions as those shown in the drawings of the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted. The various features of the first and second embodiments can be applied in combination with the present embodiment.

In this embodiment, as in the second embodiment, a system for holding a plurality of pieces of line information is considered.

For example, when the pixels are arranged as shown in FIG. 8A, as shown in FIG. 8B, a latent image is formed on a line of interest based on information on one line before and after the line of interest. Consider a combination of lasers. Note that, in the following description, the line of interest is also referred to as an n line, and one line before or one line before the line is an n-1 line.
One line after or one line after is also called an (n + 1) th line.

At this time, in the present embodiment, FIG.
As shown in (c), a light source that emits light at the center with respect to the line of interest is a main light source 21, and a latent image A based on information one line before the latent image by the main light source 21.
Is a sub A light source, and a light source that forms a latent image B based on one line of information after the latent image from the main light source 21 is a sub B light source.

That is, for the line of interest, the normal light emission and the sequence of the photosensitive member 1 are followed, and a latent image is given above and below the sub-scanning position by the sub-A light source and the sub-B light source. . This place corresponds to a specific part of the present invention.

As a result, an image is formed as shown in FIG. 8D in the ordinary writing optical device, whereas in the writing optical device of the present embodiment, the image is formed as shown in FIG.
As shown in (e), a smoother image can be formed.

In this embodiment, a device for controlling light emission for three lines and holding / delaying information is further required as a configuration of the apparatus. Therefore, the configuration is simpler than that of a normal smoothing printing system.

In the writing optical device adopting this configuration, the normal writing operation, that is, the writing operation without smoothing can be performed by stopping the light emission of the sub-A light source and the sub-B light source. For this reason, if there is a concern that the image quality may be impaired by using the smoothing function according to the selection by the user, the function can be turned off to form an image.

In the present embodiment, the sub-light source and the sub-B light source only provide latent images above and below the sub-scanning position with respect to the line of interest, but this is not necessarily limited to this. Instead, for example, it is possible to control the light emission of the main light source 21 and the sub-A light source and the sub-B light source by holding and calculating information of one line before and after the line of interest.

That is, in this embodiment, first, the main light source operates so as to reproduce the information of the line of interest so as to reproduce the pixel arrangement of the normal print resolution. In other words, an operation capable of forming an image without normal smoothing is performed in the writing operation using only the main light source.

As shown in FIG. 8C, the sub-B light source is composed of an n-line which is the line of interest and n-line which is one line before.
It is assumed that an optical path is formed so as to form an image closer to the n-th line between the -1 line and the -1 line. That is, an optical path is taken so that an image is formed in an upper portion near the target line. Further, the sub-B light source has n lines and n + 1 after one line.
It is assumed that an optical path is formed so as to form an image closer to the n-th line between the lines. That is, an optical path is taken so that an image is formed in the lower part near the line of interest.

For one pixel drawn by the main light source 21, one pixel drawn by the sub-A light source and the sub-B light source
It is assumed that the pixel size is small. At this time, the sub-A light source and the sub-B light source emit light with a light amount that does not cause a potential change that does not cause visualization when independent dots are formed, but with a larger beam diameter than the main light source 21. It shall be.

Further, other rules for light emission of the sub-A light source and the sub-B light source are as follows: (1) When only the n-th line emits light, that is, when one dot in white, one line in white, etc. , And the sub-line does not emit light. (2) When the pixels on the n-th line and the (n-1) -th line are black and black, the sub-a light source does not emit light at the main scanning position. Similarly, when the pixels on the nth line and the (n + 1) th line are black and black, the sub-B light source does not emit light at the main scanning position. (3) The lighting conditions of the sub-A light source and the sub-B light source are as shown in FIG.
(A) The sub-A light source and the sub-B according to the light emission rules shown in (b)
The light source is controlled.

According to the above-described method, an interpolated pixel can be generated according to the rise and fall of the jagged image, and a smooth image can be obtained.

Specifically, the detection around the edge and the light emission of the sub-A light source and the sub-B light source are performed as follows. (1) Detection of Edge of Line of Interest and Line One Line Ahead First, as shown in FIG.
An edge in the sub-scanning direction is detected based on a density relationship with a pixel at the same main scanning position before the line. Then, a portion where the density changes from white to black or black to white is determined as an edge.

Here, the coordinates of the pixel of interest are (x, y), and the density of the pixel is f (x, y). It is assumed that the density value is 1 when the pixel is black and 0 when the pixel is white.
Further, the operation for obtaining the density relationship with the pixel at the same main scanning position one line before is performed by g (x, y), f (x, y) -f (x,
y-1). At this time, g returns -1, 0, and 1; (2) Detection of the edge end and edge length of the line of interest and the line preceding by one line The edge of the edge is detected by comparing the result of (1) in the main scanning direction. Specifically, the following is performed.

The aforementioned g (x + 1, y) −g (x, x
y) is calculated, and the result is set as h (x, y). This h
The end of the edge is obtained from the value of (x, y). Where h
Takes a value of -2 to 2, but when it is 0, that is, when there is no change from the edge state next to the main scanning, it is determined to be a non-edge.

When the value is any other value, there is a change from the edge state adjacent to the main scan, so the pixel of interest (x, y) is assumed to be the edge of the edge.

The edge state g is compared for the target pixel and the immediately preceding pixel, and the distance of the target pixel from the edge of the edge is determined. However, it is determined from the origin in the direction of the main scanning direction (direction from left to right). Also,
When the edge state g including the pixel of interest coincides with the state g of the immediately preceding column, 1 is added to the value of the distance from the edge of the edge. Note that the value of the distance from the end of the edge is i (X,
y).

For example, as shown in FIG. 11A, since g of the pixel row of interest is the same as that of the immediately preceding pixel row, + i
Since 1 is added and the previous is the end of the edge, i
(X, y) = 1. If the x + 1-th column is in the same edge state, i (x + 1, y) = 2.

In the opposite direction, that is, in the direction from right to left, a change in the state g of the edge is detected.

When the edge state g including the pixel of interest coincides with the state g in the immediately preceding column, one is added to the value of the distance from the edge of the edge. Note that the value of the distance from the edge of the edge is j (x, y).

For example, as shown in FIG. 12 (b), since the pixel row of interest and g of the immediately preceding pixel row are the same, +1 is added to j, and the previous edge is the edge end. So j
(X, y) = 1.

Further, distances from both ends of the edge of the edge of the target pixel, that is, both sides of the left end and the right end are obtained from the above i (x, y) and j (x, y). At the same time, as shown in FIG.
It is determined by (x, y) + j (x, y) +1. (3) Detection of Edge of Line of Interest and Line After One Line Subsequently, as shown in FIG.
The edge in the sub-scanning direction is detected based on the density relationship with the pixel at the same main scanning position one line later.

At this time, a portion where the density changes from white to black or black to white is determined as an edge. Here, the coordinates of the target pixel are (x, y). Further, the density of the pixel is set to f (x, y)
And Further, it is assumed that the density value is 1 when the pixel is black and 0 when the pixel is white.

The operation for obtaining the density relationship with the pixel at the same main scanning position after one line is represented by g (x, y) = f (x,
y) -f (x, y + 1). At this time, g is -1,
0 and 1 are returned, but when it is -1 and 1, it is determined that an edge has occurred. (4) Detection of edge and edge length of the line of interest and the line after one line Further, the result of (3) is compared in the main scanning direction to detect the edge of the edge.

The above-described g (x + 1, y) -g (x,
y) is calculated, and the result is set as h (x, y). The end of the edge is obtained from this value. Here, h is −2 to 2
However, when it is 0, that is, when there is no change from the edge state next to the main scanning, it is determined to be a non-edge. When the value is any other value, a change from the edge state adjacent to the main scan occurs, so the pixel of interest (x, y) is assumed to be the edge of the edge.

The state g of the edge is compared for the target pixel and the immediately preceding pixel, and the distance from the edge of the edge of the target pixel is obtained. However, the direction of the main scanning direction from the origin,
That is, the direction is determined from left to right. When the edge state g including the pixel of interest coincides with the state g in the immediately preceding column, the distance from the edge of the edge (this is l (x,
y)) is incremented by one. For example, FIG.
As shown in (b), g of the pixel row of interest and the immediately preceding pixel row
Are the same, +1 is added to i, and i (x, y) = 1 because the immediately preceding edge is the end of the edge. If the x + 1-th column is in the same edge state, i (x + 1, y) = 2.

Further, the fluctuation of the edge state g is also detected in the opposite direction, that is, in the direction from right to left.

When the edge state g including the pixel of interest coincides with the state g in the immediately preceding column, one is added to the value of the distance from the edge of the edge (this is k (x, y)). Go.
For example, as shown in FIG. 12B, +1 is added to q because the g of the pixel row of interest and the immediately preceding pixel row are the same, and j (x, y) = 1.

Further, the distance from both ends of the edge of the edge of the target pixel, that is, the distance from the left end and the right end, is obtained from the above i (x, y) and j (x, y). At the same time, as shown in FIG. 13B, the edge length is also obtained by i (x, y) + j (x, y) +1. (5) Acquisition of information on the pixel state around both ends of the edge By the operation up to the previous stage, information on the length of the edge including the target pixel and the position of both ends of the edge is obtained. That is,
Whether the pixel of interest is on the edge or non-edge, and if the pixel of interest is on the edge, whether the pixel of interest is an edge in relation to the line of interest and the front / back line, white → black, black → white , The length of the edge, and the position of the edge of the pixel of interest are obtained.

Therefore, next, information of each of three pixels on both sides of the edge is obtained.

More specifically, the pixel states of three lines at the main scanning position (not including the corresponding edge) adjacent to both ends of the edge, that is, the line of interest, and a total of three points on one line before and one line after the line of interest Ask for.

As shown in FIGS. 13 (a) and 13 (b), when the position of the target pixel is (x, y), information of three pixels adjacent to the left end of the edge is l (x, y), and the right end of the edge is Let r (x, y) denote information of three adjacent pixels. At this time, l (x,
y) and r (x, y) are, respectively, l (x, y) = ｛f (xi−1, y−1), f (x−
i−1, y), f (xi−1, y + 1)｝ r (x, y) = ｛f (x + j + 1, y−1), f (x +
j + 1, y) and f (x + j + 1, y + 1)}.

Since the density value f is 0 or 1, information of 0/1 is arranged in the order of the pixel one line before, that is, the upper pixel, the target line pixel, and the pixel after one line, that is, the lower pixel, and the 3-bit value is 1 Return to (x, y) and r (x, y). Then, l for each pixel on the same edge
And r have a common value.

This is because counting is performed from three pixels adjacent to the left and right edges of the edge. (6) Edge Shape Detection The shape of the edge including the pixel of interest is determined using the state of the edge of each pixel, the position of the edge, and the state of the pixels adjacent to the left and right edges of the edge, obtained in the previous operation. .

Here, the shapes of the edge including the pixel of interest include, as shown in FIGS. 14A to 14F, the case where the edge becomes an edge in relation to the line of interest and the previous line, and FIG.
As shown in (a) to (f), there are two types, that is, an edge in relation to a line of interest and a subsequent line, and these are the pixels required for edge count determination.

By the operation at the preceding stage, information on whether the target line including the target pixel is an edge of a black pixel or an edge of a white pixel, and whether the target line is an edge in the relationship between the previous line and the target line, or the target line and the subsequent line Is obtained, and information on the arrangement of pixels adjacent to the left and right of the edge of the edge is obtained.

Therefore, for example, when the target edge is an edge composed of white pixels and is an edge in relation to the previous line (one line before is a line of black pixels), both edges of the edge are adjacent to each other. 14 according to the pixel state of FIG.
There is a case of a step falling to the right shown in FIG. 14A, a step of falling to the left shown in FIG. 14B, and a depression shown in FIG. 14C.

On the other hand, when the edge of interest is an edge composed of black pixels and is an edge in relation to the previous line (a line immediately before is a line of white pixels), pixels adjacent to the edge of the edge are located on both sides. Depending on the state, there is a step descending to the right as shown in FIG. 14D, a step descending to the left as shown in FIG. 14E, and a depression shown in FIG.

When none of the above conditions applies, this edge is assumed to be a non-step.

Similarly, when the target edge is an edge composed of white pixels and is an edge in relation to a subsequent line (note that one line is a black pixel line after one line), both edges of the edge are adjacent to each other. Depending on the state of the pixel, there is a step descending to the right as shown in FIG. 15A, a step descending to the left as shown in FIG. 15B, and a depression as shown in FIG.

When the edge of interest is an edge composed of black pixels and is an edge in relation to a subsequent line (note that one line becomes a white pixel line), pixels adjacent to the edge of the edge are located on both sides. Depending on the state, there is a step descending to the right as shown in FIG. 15D, a step descending to the left as shown in FIG. 15E, and a depression as shown in FIG.

When none of the above conditions applies, this edge is assumed to be a non-step. Further, FIGS. 14 (a) and 14 (b)
In the case of (d) (e) and FIGS. 15 (a), (b), (d), and (e), it is determined whether the edge is in the middle of the edge, Is determined. Specifically, it is as follows.

When an edge composed of white pixels is a lower right edge in relation to the previous line, FIG.
As shown in FIG. 7A, it is determined whether the step is in the middle or at the end in the pixel state a shown in FIG.

When an edge composed of white pixels is a lower left edge in relation to the previous line, FIG.
As shown in (b), it is determined whether the step is in the middle or at the end in the pixel state of a shown in FIG.

When an edge composed of black pixels is a lower right edge in relation to the previous line, FIG.
As shown in (d), it is determined whether the step is in the middle or at the end in the pixel state of x and y shown in FIG.

When an edge composed of black pixels is a lower left edge in relation to the previous line, FIG.
As shown in (e), it is determined whether the step is in the middle or at the end in the pixel state of x and y shown in FIG.

When an edge composed of white pixels is a lower right edge in relation to a subsequent line,
As shown in FIG. 7A, it is determined whether the step is in the middle or at the end in the pixel state a shown in FIG.

When an edge composed of white pixels is a left-falling edge in relation to the following line,
As shown in (b), it is determined whether the step is in the middle or at the end in the pixel state of a shown in FIG.

When an edge composed of black pixels is a lower right edge in relation to a subsequent line, FIG.
As shown in (d), it is determined whether the step is in the middle or at the end in the pixel state of x and y shown in FIG.

When an edge composed of black pixels is a lower left edge in relation to a subsequent line, FIG.
As shown in (e), it is determined whether the step is in the middle or at the end in the pixel state of x and y shown in FIG. (7) Emission of sub-A light source and sub-B light source Based on the above description, the blinking of each sub-beam is controlled based on the target line and the state determined from the pixel arrangement information one line before and one line after.

Here, as described above, the sub-A light source is
One line before the line of interest, that is, the nth line, that is, n
It is assumed that an optical path is formed between the first line and the n-th line, that is, an image is formed in an upper portion near the target line. Further, the sub-B light source takes an optical path so that an image is formed one line after the line of interest, that is, the nth line, that is, between the (n + 1) th line and closer to the nth line, that is, below the line of interest. I do.

First, as shown in FIG. 16 (a), a description will be given of a case where the target edge is a white pixel and a pixel is determined to be a right-downward step due to the relationship of the previous line.

In this case, whether the target edge is in the middle of the step or the left end of the edge depends on the state of the pixel a shown in FIG.
Alternatively, it is determined whether the end of the step is present.

In this embodiment, when the pixel a is white, it is determined that the step is in the middle of the step, while when the pixel a is black, the left end of the edge is determined as the end of the step.

If it is determined that the target edge is in the middle of the step, as shown in FIG. 16 (b), a pixel from the left end of the edge to a length of 3/5, that is, a white pixel is stored and the sub A The light source is driven to emit no light. The sub-A light source is driven to emit light by inverting the pixels from 3/5 or more to the right end, that is, setting the pixels to black pixels.

On the other hand, when it is determined that the target edge is the end of the step, as shown in FIG. 16 (c), the pixels from the left end of the edge to the length 2/3, that is, the white pixels are stored and the sub A The light source is driven to emit no light. The sub-A light source is driven to emit light by inverting the pixels from 以上 or more to the right end, that is, turning the pixels into black pixels.

Next, as shown in FIG. 17 (a), a case will be described in which the target edge is a white pixel and the level of the edge is determined to be the lower left step from the relationship of the previous line.

In this case, in addition to the pixel state necessary for determining the level difference, whether the target edge is in the middle of the level difference or the left end of the edge depends on the state of the pixel a shown in FIG.
Alternatively, it is determined whether the end of the step is present.

In this embodiment, when the pixel a is white, it is determined that the target edge is in the middle of the step, while when the pixel a is black, the right end of this edge is determined as the end of the step.

When it is determined that the target edge is in the middle of the step, as shown in FIG. 17B, the pixels from the right end of the edge to the length 3/5, that is, the white pixels are stored and the sub A The light source is driven to emit no light. In addition, the pixels from 3/5 or more to the left end are inverted, that is, black
The light source is driven to emit light.

On the other hand, when it is determined that the target edge is the end of the step, as shown in FIG. 17C, the pixels from the right end of the edge to the length of 2/3, that is, the white pixels are stored and the sub A The light source is driven to emit no light. The sub-A light source is driven to emit light by inverting the pixels from 2/3 or more to the left end, that is, turning the pixels into black pixels.

Next, as shown in FIG. 18 (a), a case will be described in which the target edge is a white pixel and a pixel state is determined to be a depression based on the relationship of the previous line.

In this case, in order to maintain the depression, FIG.
As shown in (b), the sub-A light source is driven to emit light by inverting the pixels from the left end of the edge to 1/6 of the length, that is, turning them into black pixels. Further, the sub-A light source is driven to emit no light while preserving pixels from 1/6 or more to 5/6, that is, white pixels. Further, the pixels from 5/6 or more to the right end are inverted to black pixels, and the sub-A light source is driven to emit light.

Next, as shown in FIG. 19 (a), a case will be described in which the target edge is a black pixel, and the edge state is determined to be a step falling rightward from the relationship of the previous line.

In this case, in addition to the pixel states necessary for determining the level difference, the state of the x and y pixels shown in FIG. 11A indicates that the target edge is in the middle of the level difference or the left end of the edge is the end of the level difference. Is determined.

In this embodiment, when the pixel x and the pixel y are black, it is determined that the target edge is in the middle of the step, and otherwise, the left end of this edge is determined to be the end of the step.

When it is determined that the target edge is in the middle of the step, as shown in FIG. 19B, the pixels from the left end of the edge to the length of 3/5, that is, the black pixels are stored and the sub A The light source is driven to emit light. Also, the sub-A light source is driven to emit no light by inverting the pixels from 3/5 or more to the right end to white pixels.

On the other hand, for example, when it is determined that the left end of the edge is the end of the step, as shown in FIG. 19C, the pixels from the left end of the edge to the length 2/3, that is, the black pixels are stored. The sub-A light source is driven to emit light. Also, the pixels from 以上 or more to the right end are inverted to white pixels, and the sub-A light source is driven to emit no light.

Next, as shown in FIG. 20 (a), a description will be given of a case where the target edge is a black pixel and a pixel is determined to be a step lowering left from the relationship of the previous line.

In this case, in addition to the pixel state necessary for determining the level difference, the target edge is in the middle of the level difference, or the left end of the edge is the end of the level difference depending on the state of the x and y pixels shown in FIG. Is determined.

In this embodiment, when the pixel x and the pixel y are black, it is determined that the target edge is in the middle of the step, and otherwise, the right end of this edge is determined as the end of the step.

When it is determined that the target edge is in the middle of the step, as shown in FIG. 20 (b), the pixels from the right end of the edge to the length 3/5, that is, the black pixels are stored and the sub A The light source is driven to emit light. Further, the pixels from ／ or more to the left end are inverted to be white pixels, and the sub-A light source is driven to emit no light.

On the other hand, when it is determined that the right end of the edge is the end of the step, as shown in FIG. 20C, the pixels from the right end of the edge to the length of 2/3, that is, the black pixels are stored. The sub-A light source is driven to emit light. Also, the pixels from 以上 or more to the left end are inverted to white pixels, and the sub-A light source is driven to emit no light.

Next, as shown in FIG. 21A, a case will be described in which the target edge is a black pixel, and the pixel state is determined to be a dent from the relationship of the previous line.

In this case, in order to maintain the depression, FIG.
As shown in (b), the pixels from the left end of the edge to the length 1/6 are inverted to white pixels, and the sub-A light source is driven to emit no light. The sub-A light source is driven to emit light while preserving pixels from 1/6 to 5/6, that is, black pixels. In addition, 5
The pixels from / 6 or more to the right end are inverted to white pixels, and the sub-A light source is driven to emit no light.

Next, as shown in FIG. 22 (a), a description will be given of a case where the target edge is a white pixel, and the pixel is determined to be a step lower rightward of the edge from the relationship of the subsequent line.

In this case, in addition to the pixel state necessary for determining the step, it is determined whether the target edge is in the middle of the step or the left end of the edge is the end of the step based on the state of the pixel a shown in FIG. I do.

In this embodiment, when the pixel a is white, it is determined that the target edge is in the middle of the step, while when the pixel a is black, the right end of this edge is determined as the end of the step.

When it is determined that the target edge is in the middle of the step, as shown in FIG. 22 (b), a pixel from the right end of the edge to a length of 3/5, that is, a white pixel is stored, and The B light source is driven to emit no light. The sub-B light source is driven to emit light by inverting the pixels from 3/5 or more to the left end to black pixels.

On the other hand, when it is determined that the end of the step is at the end, as shown in FIG. 22C, the pixels from the right end of the edge to the length of 2/3, that is, the white pixels are stored, and Non-light-emitting drive is performed. Further, the pixels from 以上 or more to the left end are inverted to black pixels, and the sub-B light source is driven to emit light.

Next, as shown in FIG. 23 (a), a description will be given of a case where the target edge is a white pixel and the level of the edge is determined to be a step lower leftward from the relationship of the subsequent line.

In this case, in addition to the pixel state necessary for determining the step, it is determined whether the target edge is in the middle of the step or the right end of the edge is the end of the step based on the state of the pixel a shown in FIG. I do.

In this embodiment, when the pixel a is white, it is determined that the target edge is in the middle of the step, while when the pixel a is black, the left end of this edge is determined as the end of the step.

When it is determined that the target edge is in the middle of the step, as shown in FIG. 23 (b), a pixel from the left end of the edge to a length of 3/5, that is, a white pixel is stored, and The B light source is driven to emit no light. In addition, the pixels from 以上 or more to the right end are inverted to black pixels, and the sub-B light source is driven to emit light.

On the other hand, when it is determined that the left end of the edge is the end of the step, as shown in FIG. 23 (c), the pixels from the left end of the edge to the length 2/3, that is, the white pixels are stored. The sub-B light source is driven to emit no light. Further, the pixels from ／ or more to the right end are inverted to black pixels, and the sub-B light source is driven to emit light.

Next, as shown in FIG. 24 (a), a case will be described in which the target edge is a white pixel and a pixel state is determined to be a depression based on the relationship of the subsequent line.

In this case, in order to maintain the depression, FIG.
As shown in (b), the pixels from the left end of the edge to the length of 1/3 are inverted to black pixels, and the sub-B light source is driven to emit light. In addition, the pixels of 1/3 or more to 2/3, that is, white pixels are stored, and the sub-B light source is driven to emit no light. further,
The pixels from 3/2 or more to the right end are inverted to black pixels, and the sub-B light source is driven to emit light.

Next, as shown in FIG. 25 (a), a case will be described in which the target edge is a black pixel and the level of the edge is determined to be a step down to the right from the relationship of the following line.

In this case, in addition to the pixel state necessary for determining the level difference, whether the target edge is in the middle of the level difference or the right end of the edge is the end of the level difference depending on the state of the pixels x and y shown in FIG. Is determined.

In this embodiment, when the pixel x and the pixel y are black, it is determined that the target edge is in the middle of the step.
At other times, the right end of this edge is determined to be the end of Danpo.

When it is determined that the target edge is in the middle of the step, as shown in FIG. 25 (b), the pixels from the right end of the edge to the length 3/5, that is, the black pixels are stored and The B light source is driven to emit light. Further, the pixels from 以上 or more to the left end are inverted to white pixels, and the sub-B light source is driven to emit no light.

On the other hand, when it is determined that the target edge is the end of the step, as shown in FIG. 25 (c), the pixels from the right end of the edge to the length 2/3, that is, the black pixels are stored and The B light source is driven to emit light. In addition, the pixels from 以上 or more to the left end are inverted to white pixels, and the sub-B light source is driven to emit no light.

Next, as shown in FIG. 26 (a), a description will be given of a case where the target edge is a black pixel and a pixel is determined to be a step lowering the left edge of the edge from the relationship of the subsequent line.

In this case, in addition to the pixel state necessary for determining the level difference, whether the target edge is in the middle of the level difference or whether the left end of the edge is the end of the level difference depends on the state of the x and y pixels shown in FIG. Is determined.

In this embodiment, when the pixel x and the pixel y are black, it is determined that the target edge is in the middle of the step.
Otherwise, the left end of this edge is determined to be the end of the step.

When it is determined that the target edge is in the middle of the step, as shown in FIG. 26 (b), a pixel from the left end of the edge to a length of 3/5, that is, a black pixel is stored, and The B light source is driven to emit light. Also, the pixels from 以上 or more to the right end are inverted to white pixels, and the sub-B light source is driven to emit no light.

On the other hand, when it is determined that the left end of the edge is the end of the step, as shown in FIG. 26 (c), a pixel from the left end of the edge to a length of 2/3, that is, a black pixel is stored. The sub-B light source is driven to emit light. Further, the pixels from ／ or more to the right end are inverted to white pixels, and the sub-B light source is driven to emit no light.

Next, as shown in FIG. 27 (a), a case will be described in which the target edge is a black pixel and a pixel state is determined to be a dent from the relationship of the following line.

In this case, in order to maintain the depression, FIG.
As shown in (b), the pixels from the left end of the edge to the length of 1/3 are inverted to white pixels, and the sub-B light source is driven to emit no light. The sub-B light source is driven to emit light while preserving the pixels from 1/3 or more to 2/3, that is, the black pixels. In addition, 2
The pixels from / 3 or more to the right end are inverted to white pixels, and the sub-B light source is driven to emit no light.

If the above case does not apply,
It is determined that the target line is a non-edge, and the sub-A light source and the sub-B light source are not driven.

As described above, in the writing optical device according to the present embodiment, the correcting means turns on the plurality of sub-A light sources and the plurality of sub-B light sources based on the plurality of line information, thereby performing the multiple line processing for performing printing smoothing. Lighting means is provided.

For this reason, the plural-line lighting means performs a printing smoothing process by lighting a plurality of sub-B light sources and a plurality of sub-B light sources based on a plurality of line information.
Thus, the print image is corrected.

Accordingly, each of the sub-A light source and the sub-B light source is turned on based on information of a plurality of lines to form a sub-latent image, so that smoothing processing can be performed more accurately and more precisely.

Also, in the writing optical device of the present embodiment, the information of the preceding and following lines and the information of the corresponding line are calculated,
A specific portion sub-beam generating means for generating a latent image on the photoreceptor 1 by a beam of each of the sub-A light source and the sub-B light source only at a specific portion is provided.

Therefore, the specific portion sub beam generating means calculates the information of the preceding and following lines and the information of the corresponding line,
A latent image is generated on the photoconductor 1 by the beams of the sub-A light source and the sub-B light source only at a specific portion.

Therefore, by controlling the light emission of each of the sub-A light source and the sub-B light source to a specific portion with reference to the target line and the pixel information before and after the target line, a high-quality image can be obtained more accurately.

In the writing optical apparatus according to the present embodiment, the edge determining means determines a portion corresponding to an edge of an image, and obtains a length and a shape corresponding to the edge.

The plural line lighting means interpolatively generates a latent image by a sub beam based on the length and shape of a portion corresponding to an edge by the edge judging means.

For this reason, it is possible to detect a step of a line having a shallow angle by the edge judging means, so that it is possible to control the generation of an interpolation pixel according to the angle, that is, the length of the edge. In particular, since the oblique lines having a small angle are appropriately subjected to the smoothing process, a smoother image can be reproduced.

In the writing optical apparatus according to the present embodiment, the edge determining means determines the edge state based on pixel information of the line of interest and the lines before and after the line of interest as a method of detecting the edge and the length of the edge. The edge information is compared from both ends of the line in the main scanning direction, and the position of the end of the edge and the length of the edge are obtained.

Therefore, as a method of edge detection and edge length, an edge is detected by comparing pixels of peripheral lines, and the edge information is detected from both ends of the line in the main scanning direction. , The position and length of the edge of the edge can be determined. For this reason, a hardware configuration can be realized by using a line memory, so that an inexpensive configuration can be realized.

In this embodiment, when detecting the edge shape, information on the edge state, edge length, and peripheral pixel states at both ends of the edge are referred to.

For this reason, when detecting the shape of an edge, the edge state can be grasped with higher accuracy by referring to the information on the length of the edge state edge and the pixel states around both ends of the edge. Smooth image reproduction can be obtained.

In the present embodiment, the edge shape is detected by detecting three types of downward slope, downward slope, and depression.

For this reason, the shape detection and classification are classified into three types.
Since edge shape detection is performed, processing can be performed by a simple algorithm. As a result, smoother image reproduction can be obtained with an inexpensive hardware configuration.

In this embodiment, the emission of the sub-beam is controlled according to the three types of detection results.

For this reason, as the shape detection, the edge shapes are classified into three types, that is, lower left, lower right, and hollow, and the generation of interpolation pixels is controlled according to the type. it can.

In this embodiment, when it is determined that the end of the step and the depression are determined based on the state of the edge end, the correction control is changed.

For this reason, when it is determined that a step (edge) is at the end or a depression, smoothing is performed by changing the normal processing method and the correction method, thereby further optimally maintaining the characteristics of the original image. Smooth image reproduction can be obtained.

[Embodiment 4] Another embodiment of the present invention is described below with reference to FIG. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 3 are given the same reference numerals, and descriptions thereof are omitted. The various features of the first to third embodiments can be applied in combination with the present embodiment.

In the first to third embodiments, a laser diode is used as a light source.

However, an LED lamp array is often used in a small and inexpensive copying machine or the like. In this embodiment, an LED in which light sources flickering by the number of effective print pixels are arranged.
The correction when a latent image is formed on the photoconductor 1 by the lamp array will be described.

That is, when an electrostatic latent image is formed on the photosensitive member 1, a blinking signal of the light source is formed in units of pixel information of one line in the main scanning, and is input to the apparatus.

At this time, usually, the number of light sources (the number of light emitting elements)
In addition, the writing resolution in the main scanning direction is determined based on the setting intervals. The writing resolution in the sub-scanning direction is determined by the interval between the main scanning lines of the latent image, that is, the moving speed of the photoconductor 1.

In the writing optical device and the photosensitive member 1, the data resolution of the image data input to the writing optical device is the main scanning data resolution Rim and the sub-scanning data resolution Ris, while the latent image of the writing latent image on the photosensitive member is provided. Resolution is main scanning writing resolution Rom, sub-scanning writing resolution Ro
Consider especially the writing optical device that is s. Also, Rim =
Let Sd1 be the moving speed of the photoconductor 1 when Rom, Ris = Ros. In other words, this condition indicates that the image data and the writing latent image have an equal magnification relationship.

Here, for example, when doubling the resolution of the latent image in the main scanning direction, it is necessary to double the number of pixels in the input main scanning. Further, it is necessary to double the number of light emitting elements. On the other hand, when doubling the resolution of the latent image in the sub-scanning direction, it is necessary to double the number of input sub-scanning pixels, that is, the number of lines.

At this time, if the writing exposure time is not changed, the moving speed of the photoconductor 1 must be halved. Further, when the resolution of the sub-scanning latent image is doubled without changing the moving speed of the photoconductor 1, it is necessary to make the blink timing of the light source double the speed.

On the other hand, when doubling both the resolution of the latent image in the main scanning direction and the resolution of the latent image in the sub-scanning direction, it is necessary to double the number of pixels in the input main scanning and sub-scanning, respectively. Therefore, the data amount is quadrupled. At this time, it is necessary to double the number of light emitting elements. That is, the resolution is determined by the number of write elements in the main scan.

When the timing of the blinking of the light source is not changed, the moving speed of the photosensitive member 1 must be reduced to half. Further, when the moving speed of the photoconductor 1 is not changed, the blink timing of the light source needs to be doubled.

In each of the above cases, it is necessary to provide sufficient exposure so that the latent image can be visualized. Therefore, the pre-charging of the photosensitive member 1 or the light-emitting state of the light source or the developing device depends on the respective operating conditions. Must be managed. Further, increasing the resolution of the latent image requires preprocessing the input image data, increasing the data, and sending the data at the timing described above.

In this embodiment, the resolution of the latent image is increased without changing the data resolution. In other words, it improves the apparent resolution.

As a result, the input data need not be pre-processed, and of course, since there is no change in the apparatus or input operation, the image quality of the conventional apparatus can be improved simply by replacing the writing optical apparatus. Improvement can be achieved.

In order to achieve this effect, the writing optical device of the present embodiment has a plurality of blinkable diodes, that is, a number determined by the main scanning resolution and the printable size.

Also, one light emitting element corresponds to one pixel in the main scanning pixel, blinks and forms a latent image, and one main scanning line can be simultaneously written. ing.

Further, a lens structure is provided immediately after the light emitting element, so that the light reaches the photosensitive member 1 with a specified beam diameter and a latent image can be formed.

[0314] The above-mentioned light emitting element array is arranged at a position very close to the photosensitive member 1. Therefore, in order to reduce the size of the printing apparatus, the LSU described in the first to third embodiments is used.
2 is also better.

The light source is capable of emitting or not emitting light by sufficiently following the period of the input signal and the change in the signal. However, the writing resolution can be changed by controlling the blink pitch of the light source.
In contrast, this light-emitting element array
), The pitch of the element arrangement itself becomes the writing pixel pitch, and the writing resolution cannot be easily changed. In the direction of lowering the resolution, 1/2, 1 /
3, etc. are possible.

Various methods for smoothing using this LED lamp array will be described below.

First, it is considered to add an optical system such as a filter which has a transmittance of 1 immediately after and at the center of the LED lamp array and decreases in transmittance toward the periphery. .

At this time, the latent image and the visual image formed on the photoreceptor 1 through the optical system and the optical path are, if they are independent points, more beam spot than usual so as to obtain the same visual size as a normal unit. Size is large. In the case of a part represented by a plurality of points, FIG.
As shown in FIGS. 28 (a) and (b), even in a part which is not visible at an isolated point, as shown in FIGS. Is newly generated, and a visualized image is generated by interpolation with respect to a normal visualized image, so that a smoother image expression than in the related art is obtained.

Also, in this writing optical device, by providing a shutter mechanism which can be turned on / off arbitrarily, when turned on, the exposure from the light source forms a normal latent image and turns off smoothing. By doing so, an image can be output with the smoothing function disabled depending on the output image. As a result, an image equivalent to a conventional image is formed. This is particularly effective in the case of outputting an image having a large frequency characteristic, such as an error diffusion image, because the smoothing may cause a problem in the image quality.

As described above, in the writing optical apparatus according to the present embodiment, the correcting means arranges the light sources whose effective print pixels blink in accordance with the input image signal, and uses the light from this light source to form a latent image. Writing is collectively performed on the photoconductor line by line.
That is, for example, for example, an LED lamp array is used as a light source.

For this reason, even in a small device in which it is difficult to install the LSU 2, it is possible to correct the print image by using a light source such as an LED lamp array.

Therefore, it is possible to provide a writing optical device which receives an input image as it is at the data resolution, improves the image quality of the output image by the operation of the writing optical system, and can simplify the device and reduce the cost. .

In this embodiment, the beam spot diameter is controlled and the interpolation function is turned off in response to a request from the image forming apparatus.

For this reason, even in a device that performs writing using an LED lamp array, smoothing is turned on / off.
Can be switched. Therefore, it is possible to selectively obtain a smoothed image quality for data whose image quality may be impaired by the smoothing function.

[Fifth Embodiment] The following will describe another embodiment of the present invention. For convenience of explanation, members having the same functions as those shown in the drawings of the above-described first to fourth embodiments are given the same reference numerals, and descriptions thereof will be omitted. In addition, various features of the first to fourth embodiments can be applied in combination with the present embodiment.

In the present embodiment, a main LED array and a sub LED array are provided in a plurality of light emitting elements provided as correction means.

That is, in the writing optical device of this embodiment, first, a weaker exposure is performed on the main LED array, which is a writing optical device exactly the same as a normal writing device, and on the periphery of the main writing light by the main LED array. And a sub LED array.

The latent image created by the above-mentioned main LED array alone can form an image similar to a normal image.

The sub LED array is composed of the main LED
It has the same number of elements as or more than the array, and controls the lighting or non-lighting by following the pixel information at the same timing as that of the main LED array and performs exposure to form a latent image. However, it is assumed that the exposure and the latent image by the sub LED array are sufficiently weaker than those of the main LED array, and that the single and independent lighting of one dot is at a level that does not develop. In addition, the size at which the latent image is created is usually sufficiently larger than the latent image formed by lighting one dot of the main LED array. Further, it is assumed that the center of the sub-light emission pixel arrangement is the same as that of the main pixel arrangement at the same main scanning position.

When data is input to the writing optical device having the above configuration and a light emission and a latent image are formed, the main LE
By operating both the D array and the sub LED array, a sub latent image is generated around the main latent image.

At this time, the sub-latent image is a latent image that can be complementarily developed with respect to the main latent image according to the shape of the latent image. When this is developed together, the main LED
A smoother image can be formed than an image formed only by the array.

Further, by stopping the light emission of the sub LED array, ON / OFF control of this function can be easily performed, and the image quality can be selected.

As described above, a smoothing effect can be obtained by adding a sub LED array for emitting sub light to the conventional configuration.

Note that the present invention is not limited to the above embodiment, and various changes can be made within the scope of the present invention. For example, in the above embodiment, the sub LED array is single, but the present invention is not limited to this.
It is possible to provide a writing optical device composed of two types, that is, an array.

That is, for the main LED array,
Sub ALED array and sub BL as sub LED array
It is possible to provide a writing optical device having a total of three LED arrays, two with the ED array.

In the above writing optical device, the main LED
Thus, normal image formation can be performed. Also,
The sub-ALED array forms an image on the upper portion near the latent image pixel by the main LED array, while the sub-BLED array forms a latent image on the lower portion near the latent image pixel by the main LED array, and an isolated one dot of one pixel of the main latent image. However, depending on the sub-latent image generated vertically, the exposure intensity is such that the formed image is not affected.

When data is input to the writing optical device having the above configuration and a light emission and a latent image are formed, the main LE
By operating both the D array and the sub LED array, a sub latent image is generated around the main latent image. At this time, the saf latent image is a latent image that can be complementarily developed with respect to the main latent image according to the shape of the latent image. When this is also developed, a smoother image can be formed than an image formed only by the main LED array. Also, by stopping the light emission of the sub-ALED array and the sub-BLED array, ON / OFF control of this function can be easily performed, and the image quality can be selected.

As described above, in the writing optical device of the present embodiment, the light sources are arranged in a plurality of rows like the main LED array and the sub LED array.

For this reason, by using the LED lamp arrays in parallel, a smoothing effect can be obtained more easily in terms of configuration, and ON / OFF control thereof is facilitated.

In this embodiment, the photosensitive members 1 of the main LED array and the sub LED array are arranged between the light sources.
Are different in the size and the potential characteristics of the latent image when the image reaches the image.

For this reason, by making the potential change around the image to be developed (developed) incidentally, the image becomes smooth.

In the present embodiment, the optical paths are arranged so that the optical paths extend on one main scanning line of the photosensitive member 1 for each optical path.

Therefore, the main LED array and the sub-L
The degree of correction can be adjusted by the influence of the latent image by the ED array.

Further, in the present embodiment, the optical paths are arranged such that the optical paths extend on the sub-scanning line of the photosensitive member 1 for each optical path.

For this reason, by making the potential change incidentally around the image to be developed (developed), the image becomes smooth. In particular, the correction level in the sub-scanning direction can be increased.

[Embodiment 6] The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those shown in the drawings of the above-described first to fifth embodiments are denoted by the same reference numerals, and description thereof is omitted. In addition, various features of the first to fifth embodiments can be applied in combination with the present embodiment.

In this embodiment, a sub-ALED array (hereinafter, referred to as a “sub-A array”) and a sub-BLE
A D optical array (hereinafter referred to as a "sub-B array"), further comprising a writing optical device for inputting image signals of different lines to the main LED array, the sub-A array, and the sub-B array, respectively. Has become. Note that, for the description, the description of the third embodiment will be given.
The main light source 21 is a main LED array,
It is the same as replacing the light source with the sub-A array and replacing the sub-B light source with the sub-B array.

First, in the pixel arrangement shown in FIG. 29 (a), as shown in FIG. 29 (b), the line of interest to be written by the main LED array is set to N lines.

Also, as shown in FIG.
The array is between N and N-1 lines and
It is assumed that there is a center of latent image formation near the line. Also,
It is assumed that the number of elements and the pitch of element arrangement of the main LED array and the sub-A array are exactly the same.

On the other hand, it is assumed that the sub-B array has a center of latent image formation between the Nth line and the (N + 1) th line and near the Nth line as shown in FIG. It is assumed that the number of elements and the pitch of element arrangement of the main LED array and the sub-B array are exactly the same.

In the writing optical device having the above configuration, normal image formation can be performed by the main LED array. The sub-A array forms a latent image on the upper portion of the main LED array near the latent image pixel, and the sub-B array forms a latent image on the lower portion of the main LED array near the latent image pixel. It is assumed that the exposure intensity is such that the formed image is not affected depending on the sub-latent image generated above and below the dot.

When data is input to the writing optical device having the above configuration and a light emission and a latent image are formed, the main LE
By operating both the D array, the sub-A array, and the sub-B array, a sub-latent image is generated around the main latent image. At this time, the sub-latent image is a latent image that can be complementarily developed with respect to the main latent image according to the shape of the latent image.

When this was also developed, the main LE
A smoother image can be formed than an image formed only by the D array. Also, by stopping the light emission of the sub-A array and the sub-B array,
The N / OFF control can be easily performed, and the image quality can be selected.

For example, based on the information of one line before and after the line of interest, FIG. 29 (a) (b) (c) (d)
A combination for forming a latent image as shown in FIG.

The light source that emits light at the center of the object is the main LE
The same figure (c) based on the information of the previous line as the D array
The light source that forms the latent image of the pixel a shown in FIG. 4 is a sub-A array, and the light source that forms the latent image of the pixel b shown in FIG.

Here, the line of interest is set to the n-th line, the line before the line is set to the n-1 line, and the line after the line is set to the n + 1 line. In other words, the normal line and the sequence of the photoconductor 1 are followed for the line of interest, and a latent image is given above and below the sub-scanning position by the sub-A array and the sub-B array.

As a result, a smoother image can be formed as shown in FIG.

As a configuration of the writing optical device, a mechanism for controlling light emission for three lines and holding / delaying information is further required. However, since it is not necessary to perform various calculations to increase the resolution, it is not necessary. The configuration is simpler than that of a normal smoothing printing system.

In the device having this configuration, by stopping the light emission of the sub-A array and the sub-B array, a normal write operation without smoothing is performed as shown in FIG. If there is a concern that the image quality will be impaired by using the smoothing function according to the selection of, the function can be turned off to form an image.

In the present embodiment, the latent image is merely provided above and below the sub-scanning position by the sub-A array and the sub-B array with respect to the line of interest. However, the present invention is not limited to this. However, for example, for the line of interest, the information of one line before and after the line of interest is held and calculated, and the main LED array, and the sub-A array and sub-B
It is possible to control the light emission of the array.

That is, in the present embodiment, first, the main LED array operates so that the information of the line of interest reproduces the pixel arrangement of the normal print resolution. That is, in the writing operation of only the main LED array, an operation capable of forming an image without normal smoothing is performed.

Note that this control operation is performed according to the third embodiment.
Therefore, the description is omitted.

Therefore, the effect is the same, and the description is omitted.

[0364] Also in the present embodiment, the main L
Using the ED array, sub-A array and sub-B array,
The edge judgment can be performed by the same method as that of the fourth embodiment.

[0365]

As described above, according to the writing optical system of the present invention, the writing optical system performs
By irradiating a beam spot larger than the writing light to the normal photoconductor, a sub-latent image is formed around the main latent image by the writing light to the normal photoconductor to correct the print image. Correction means is provided.

Therefore, the correction of the print image is performed on the input image signal by the correction means provided in the writing optical system.

As a result, it is possible to increase the print quality without increasing the print resolution, which is the output resolution, beyond the data resolution, which is the input resolution, and without increasing the number of pixels.

That is, in the present invention, the input image data is directly input to the light source without any image processing before the present apparatus. Then, the correction unit provided in the writing optical system from the light source corrects the print image with respect to the input image signal.

Therefore, since the resolution input to the writing optical device remains the data resolution, the printing quality can be improved without considering the problem of increasing the speed of the writing optical device. Further, the image quality can be improved by combining with a conventional writing optical device.

Further, since the correcting means is constituted in a writing optical system for exposing the photosensitive member to form a latent image while scanning with a light source which blinks based on the input image signal, it is compact. The structure is also simple.

The correcting means irradiates the input image signal with a beam spot larger than the writing light to the normal photosensitive member, thereby forming the main latent image by the writing light to the normal photosensitive member. A sub-latent image is formed around the image to correct the print image.

As a result, the input image is received at the data resolution without any change in the configuration before the present apparatus, the image quality of the output image is improved by the operation of the writing optical system, and the apparatus is simplified and the cost is reduced. This provides an effect that it is possible to provide a writing optical device that can achieve the above.

As described above, in the writing optical device of the present invention, in the writing optical device described above, the correction means changes the transmittance of the optical path from the light source to the rotating mirror for performing scanning. It is provided with means for changing the transmittance before the rotating mirror.

Therefore, the correction means can be formed only by inserting, for example, a filter for changing the transmittance as the transmittance changing means before the rotating mirror.

Therefore, the input image is received at the data resolution without changing the configuration before this device at all.
It is possible to improve the image quality of an output image by the operation of the writing optical system, and to provide a writing optical device capable of surely simplifying the device and reducing the cost.

As described above, in the writing optical device according to the present invention, in the writing optical device described above, the correcting means changes the reflectance of the mirror surface of the rotating mirror for performing scanning. Means.

[0377] Therefore, the rotating mirror reflectance changing means corrects the print image by changing the reflectance of the mirror of the rotating mirror for scanning.

For this reason, as the rotating mirror surface reflectance changing means, for example, only by processing the rotating mirror surface of the rotating mirror,
Correction means can be formed.

Therefore, the input image is received at the data resolution without changing the configuration before this device at all.
It is possible to improve the image quality of an output image by the operation of the writing optical system, and to provide a writing optical device capable of surely simplifying the device and reducing the cost.

Further, as described above, in the writing optical device of the present invention, in the above-described writing optical device, the correction means is configured to convert the reflected light of the rotating mirror in the optical path from the rotating mirror to the photosensitive member for scanning. It is provided with a rotating mirror reflected light varying means for varying.

Therefore, the rotating mirror reflected light variation means does not require installation accuracy because it provides an optical effect at the final stage. Further, processing is easy. In addition, since the light has passed through the f-θ lens system, light at all angles with respect to the main scanning direction is at a constant speed, and distortion of the optical path due to processing hardly occurs.

Therefore, the input image is received at the data resolution without changing the configuration before this device at all.
It is possible to improve the image quality of an output image by the operation of the writing optical system, and to provide a writing optical device capable of surely simplifying the device and reducing the cost.

As described above, in the writing optical device of the present invention, in the writing optical device described above, the correcting means couples the reflected light when the writing exposure is reflected from the photosensitive member to the photosensitive member again. It is provided with a re-imaging means for imaging.

Therefore, it is possible to correct a print image without changing the configuration of a conventional writing optical device at all. In addition, since the light has passed through the f-θ lens system, the light at all angles with respect to the main scanning direction has a constant velocity, and distortion of the optical path due to processing hardly occurs.

Therefore, the input image is received at the data resolution without changing the configuration before this device at all.
It is possible to improve the image quality of an output image by the operation of the writing optical system, and to provide a writing optical device capable of surely simplifying the device and reducing the cost.

Further, as described above, the writing optical system of the present invention irradiates the writing optical system with the writing light to the ordinary photosensitive member by the main light source with respect to the input image signal. A correcting means for forming a main latent image, and forming a sub-latent image with a sub-light source different from the main light source to correct a print image is provided around the main latent image. .

Therefore, it is possible to correct a print image without changing the configuration of the writing optical system other than the light source at all. In addition, since the sub latent image is formed by the sub light source to correct the print image, the smoothing process can be performed by adjusting the sub latent image by the sub light source.

As a result, the input image is received at the data resolution without any change in the configuration before the present apparatus, the image quality of the output image is improved by the operation of the writing optical system, and the apparatus is simplified and the cost is reduced. This provides an effect that it is possible to provide a writing optical device that can achieve the above.

Further, as described above, in the writing optical device of the present invention, in the writing optical device described above, the correction means turns on a plurality of sub light sources based on a plurality of line information, thereby performing a printing smoothing process. Is provided.

[0390] Therefore, the multiple line lighting means performs printing smoothing processing by lighting a plurality of sub light sources based on a plurality of line information, thereby correcting a print image.

Accordingly, since each sub light source is turned on based on the information of a plurality of lines to form a sub latent image, there is an effect that smoothing processing can be performed more accurately and more accurately.

According to the writing optical device of the present invention, in order to solve the above-mentioned problem, in the writing optical device described above, the multi-line lighting means calculates the information of the preceding and following lines and the information of the corresponding line, and specifies the information. A specific portion sub-beam generating means for generating a latent image on the photoreceptor by the beam of each sub light source only at the portion is provided.

Therefore, the specific portion sub-beam generating means calculates the information of the preceding and following lines and the information of the corresponding line,
A latent image is generated on the photoconductor only by a beam of each sub light source at a specific portion.

For this reason, by controlling the light emission of each sub light source to a specific portion with reference to the target line and the pixel information before and after the target line, it is possible to obtain a more accurate high-quality image.

As described above, according to the writing optical device of the present invention, in the above-described writing optical device, a portion corresponding to an edge of an image is determined, and the length and shape of the portion corresponding to the edge are obtained. In addition to the edge determining means, the plural-line lighting means interpolatively generates a latent image by a sub-beam based on the length and shape of a portion corresponding to an edge determined by the edge determining means.

Therefore, it is possible to detect a step of a line having a shallow angle by the edge judging means, so that it is possible to control the generation of an interpolation pixel according to the angle, that is, the length of the edge. In particular, an oblique line having a shallow angle is appropriately subjected to the smoothing process, so that an effect that a smoother image can be reproduced can be achieved.

Further, as described above, in the writing optical device of the present invention, in the writing optical device described above, the edge judging means detects the edge and the length of the edge by using the target line and the lines before and after the target line. The edge state is determined based on the pixel information described above, and the comparison of the edge information is performed from both ends of the line in the main scanning direction to determine the position of the edge of the edge and the length of the edge.

Therefore, as a method of edge detection and edge length, an edge is detected by pixel comparison of a peripheral line, and the edge information is detected from both ends of the line in the main scanning direction. , The position and length of the edge of the edge can be determined. For this reason, since the hardware configuration can be realized by the line memory, there is an effect that an inexpensive configuration can be realized.

Further, as described above, in the writing optical device of the present invention, in the writing optical device described above, the correcting means arranges a light source whose effective print pixel number blinks according to an input image signal, and Is collectively written line by line on the photosensitive member for forming a latent image.

Therefore, even in a small device in which it is difficult to install the LSU, the print image can be corrected by a light source such as an LED lamp array.

Therefore, it is possible to provide a writing optical device which receives an input image as it is at the data resolution, improves the image quality of the output image by the operation of the writing optical system, and can simplify the device and reduce the cost. This has the effect.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a writing optical device according to the present invention, wherein (a) shows a latent image in a single spot, and (b) shows an image formed by (a). (C) shows a latent image in a plurality of spots, and (d) shows an image formed by (c).

FIG. 2A is a plan view showing a latent image image on a photoreceptor by a single spot when passing through a filter for reducing light transmittance from the center to the periphery in the writing optical device, and FIG. It is sectional drawing which shows a potential distribution.

FIG. 3 is a diagram illustrating a principle of a smoothing process in the writing optical device in the case of a single spot.
It is a top view showing on the grid | lattice which shows a printing resolution, (a)
(B) shows the spot size and the latent image on the photoreceptor by a normal writing optical device, (b) shows the spot size and the latent image on the photoreceptor when not passing through the filter by the writing optical device, (C) shows a print image when the light passes through a filter in the writing optical device.

FIG. 4 is a plan view showing a printing resolution on a grid for spots of a plurality of data in order to explain the principle of smoothing processing in the writing optical device;
(A) shows input data, (b) shows a latent image image when passed through a filter by the writing optical device, (c) shows a printing image by a normal writing optical device, (d) ) Shows a print image when the light passes through a filter in the writing optical device.

FIG. 5 is a perspective view showing a correcting means in the writing optical device, wherein (a) is a perspective view showing a polygon mirror;
(B) is a plan view showing a latent image image for a single spot, (c) is a plan view showing a print image for a single spot, and (d) is a latent image for a plurality of spots. FIG. 4E is a plan view showing an image, and FIG. 4E is a plan view showing a printed image in the case of a plurality of spots.

FIGS. 6A and 6B show another correction means in the writing optical device, wherein FIG. 6A is a structural diagram showing a case where light reflected by a photoconductor is reflected again, and FIG. It is a structural diagram showing a case where it is not performed.

7A and 7B are plan views showing another embodiment of the writing optical device according to the present invention, in which FIG. 7A is a plan view showing a latent image image in the case of a single spot, and FIG. Plan view showing a print image for the case,
(C) is a plan view showing a latent image image in the case of a plurality of spots, and (d) is a plan view showing a print image in the case of a plurality of spots.

FIGS. 8A and 8B show still another embodiment of the writing optical device according to the present invention, wherein FIG. 8A is an explanatory diagram showing an arrangement of pixels, and FIG. 8B is a latent image when a plurality of main light sources are used. (C) is a plan view showing a latent image when a plurality of main light sources, sub-A light sources and sub-B light sources are used, and (d) is a plan view showing a print image using only a plurality of main light sources. FIG. 7E is a plan view showing a print image when a plurality of main light sources, sub-A light sources, and sub-B light sources are used.

FIGS. 9A and 9B are explanatory diagrams showing lighting conditions of a sub-A light source and a sub-B light source in the writing optical device.

10A and 10B are explanatory diagrams showing a method of detecting an edge in the writing optical device, wherein FIG. 10A shows a relationship between a line of interest and one line before, and FIG. 10B shows a relationship between the line of interest and one line after. It shows.

11A and 11B are explanatory diagrams illustrating a method of detecting an edge in the writing optical device, wherein FIG. 11A illustrates an example in which edge detection is performed from left to right in relation to a line of interest and one line before; (B) shows an example in which edge detection is performed from left to right in relation to the line of interest and one line after.

12A and 12B are explanatory diagrams illustrating a method of detecting an edge in the writing optical device, wherein FIG. 12A illustrates a method of performing edge detection from right to left in relation to a line of interest and one line before; (B) shows an example in which edge detection is performed from right to left in relation to the line of interest and one line after.

13A and 13B are explanatory diagrams illustrating a method of detecting an edge in the writing optical device, wherein FIG. 13A illustrates a principle of obtaining an edge and an edge length in relation to a line of interest and one line before, and FIG. 9 shows the principle of obtaining an edge and an edge length in relation to a line and one line after.

FIGS. 14A to 14F are explanatory diagrams showing various patterns when performing edge detection from the relationship between the line of interest and one line before in the writing optical device.

FIGS. 15A to 15F are explanatory diagrams showing various patterns when performing edge detection from the relationship between the line of interest and one line after in the writing optical device.

FIGS. 16A to 16C show a case where an attention line and an immediately preceding line are edges in relation to the attention line, and the attention line including the attention pixel is an edge of a white pixel and is a right-downward edge; FIG. 9 is an explanatory diagram showing a pattern in the case and a light emission pattern of the sub-A light source.

FIGS. 17A to 17C are diagrams in which, in a case where an edge is formed in relation to a line of interest and a line preceding the line, the line of interest including the pixel of interest is an edge of a white pixel and is a left-downward edge; FIG. 9 is an explanatory diagram showing a pattern in the case and a light emission pattern of the sub-A light source.

FIGS. 18A and 18B are patterns in a case where a line of interest including a pixel of interest is an edge of a white pixel and becomes a depression when the line becomes an edge in relation to the line of interest and its previous line; FIG. 4 is an explanatory diagram showing a light emission pattern of a sub-A light source.

FIGS. 19A to 19C are diagrams in which, when an edge is formed in relation to a line of interest and a line preceding the line of interest, the line of interest including the pixel of interest is the edge of a black pixel, which is a lower right edge; FIG. 9 is an explanatory diagram showing a pattern in the case and a light emission pattern of the sub-A light source.

FIGS. 20A to 20C are diagrams in which, when an edge is formed in relation to a line of interest and a line preceding the line of interest, the line of interest including the pixel of interest is the edge of a black pixel and is a left-downward edge; FIG. 9 is an explanatory diagram showing a pattern in the case and a light emission pattern of the sub-A light source.

FIGS. 21 (a) and (b) are patterns when a line of interest including a pixel of interest is an edge of a black pixel and becomes a dent when the line of interest is an edge in relation to the line of interest. FIG. 4 is an explanatory diagram showing a light emission pattern of a sub-A light source.

FIGS. 22A to 22C show cases where a line of interest including a pixel of interest is an edge of a white pixel and is a right-downward edge when edges are formed in relation to a line of interest and a subsequent line. FIG. 4 is an explanatory diagram showing a pattern of the sub-B light source and a light emission pattern of the sub-B light source.

FIGS. 23A to 23C show cases in which a line of interest including a pixel of interest is an edge of a white pixel and is a left-downward edge when edges are formed in relation to a line of interest and a subsequent line. FIG. 4 is an explanatory diagram showing a pattern of the sub-B light source and a light emission pattern of the sub-B light source.

FIGS. 24A and 24B are diagrams showing a pattern in a case where a line of interest including a pixel of interest is an edge of a white pixel and becomes a hollow when the line becomes an edge in relation to the line of interest and a subsequent line; FIG. 4 is an explanatory diagram showing a light emission pattern of the sub-B light source.

FIGS. 25A to 25C show a case where a line of interest including a pixel of interest is an edge of a black pixel and is a right-downward edge when edges are formed in relation to a line of interest and a subsequent line. FIG. 4 is an explanatory diagram showing a pattern of the sub-B light source and a light emission pattern of the sub-B light source.

FIGS. 26A to 26C show cases in which a line of interest including a pixel of interest is an edge of a black pixel and is a left-downward edge in a case where the line is an edge in relation to the line of interest and a subsequent line. FIG. 4 is an explanatory diagram showing a pattern of the sub-B light source and a light emission pattern of the sub-B light source.

FIGS. 27 (a) and (b) show patterns when a line of interest including a pixel of interest is an edge of a black pixel and becomes a dent when edges are formed in relation to a line of interest and a subsequent line; FIG. 4 is an explanatory diagram showing a light emission pattern of the sub-B light source.

FIG. 28 shows still another embodiment of the writing optical device according to the present invention, in which (a) shows a latent image in a spot formed by a single LED lamp array,
(B) shows an image formed by (a),
(C) shows a latent image in a spot formed by a plurality of LED lamp arrays, and (d) shows an image formed by (c).

FIGS. 29A and 29B show still another embodiment of the writing optical device according to the present invention, in which FIG. 29A is an explanatory diagram showing an arrangement of pixels, and FIG. 29B is a case where a main light source of a plurality of LED lamp arrays is used. (C) is a plan view showing a latent image when a main LED array including a plurality of LED lamp arrays and a sub-A array and a sub-B array are used, and (d) is a plan view showing a latent image. FIG. 3E is a plan view showing a print image of only the main LED array of the LED lamp array, and FIG.
FIG. 9 is a plan view showing a print image when an ED array, a sub-A array, and a sub-B array are used.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 LSU (writing optical device) 10 Polygon mirror (rotating mirror, rotating mirror surface reflectance variation means) 11 Mirror (re-imaging means) 21 Main light source

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuru Tokuyama 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside (72) Inventor Mihoko Tanimura 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Incorporated (72) Inventor Noriyasu Yasuoka 22-22 Nagaikecho, Abeno-ku, Osaka, Osaka Sharp Co., Ltd. (72) Inventor ▲ Saki ▼ Ta Hiroshi 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka In-house F-term (reference) 2C362 AA22 AA31 BA05 BA86 CB18 CB21 CB24 CB26 CB27 CB32 CB37 2H076 AB06 AB12 AB18 5C072 AA03 BA02 BA15 BA16 BA20 HA01 HA06 HA13 HB10 JA07 UA11 XA01 XA05 5C074 AA03 BB11

Claims (11)

[Claims] A writing optical system provided in an image forming apparatus that prints out an input image and forms a latent image by exposing a photosensitive member while scanning with a light source that blinks based on an input image signal. In the writing optical device comprising: the writing optical system, for the input image signal,
By irradiating a beam spot larger than the writing light to the normal photoconductor, a sub-latent image is formed around the main latent image by the writing light to the normal photoconductor to correct the print image. A writing optical device comprising a correction unit. 2. The apparatus according to claim 1, wherein the correcting means includes a transmittance changing means in front of the rotating mirror for changing the transmittance of an optical path incident on the rotating mirror for scanning from the light source. Writing optics. 3. The writing optical apparatus according to claim 1, wherein the correcting means includes a rotating mirror reflectance changing means for changing a reflectance of a mirror surface of the rotating mirror for performing scanning. 4. The apparatus according to claim 1, wherein said correcting means includes a rotating mirror reflected light varying means for varying reflected light of the rotating mirror in an optical path from the rotating mirror to the photosensitive member for scanning. Writing optics. 5. The writing apparatus according to claim 1, wherein said correction means includes a re-imaging means for forming an image of the reflected light when the writing exposure is reflected from the photoreceptor on the photoreceptor again. Optical device. 6. A writing optical system provided in an image forming apparatus for printing out an input image and forming a latent image by exposing a photosensitive member while scanning with a light source blinking based on an input image signal. In the writing optical device comprising: the writing optical system, for the input image signal,
The main light source irradiates the writing light to the normal photoconductor to form a main latent image, and a sub-latent image is formed around the main latent image with a sub light source different from the main light source A writing optical device, comprising: a correction unit that corrects a print image by using the correction unit. 7. The writing device according to claim 6, wherein the correction means includes a plurality of line lighting means for performing a printing smoothing process by lighting a plurality of sub light sources based on a plurality of line information. Optical device. 8. A plurality of line lighting means includes a specific part sub-beam generating means for calculating information of the preceding and succeeding lines and information of the corresponding line, and generating a latent image on a photosensitive member only by a beam of each sub light source at a specific part. 8. The writing optical device according to claim 7, wherein: 9. An edge determining means for determining a part corresponding to an edge of an image and obtaining a length and a shape of a part corresponding to the edge, and the plural line lighting means corresponds to the edge by the edge determining means. 9. The writing optical device according to claim 8, wherein a latent image by a sub-beam is generated interpolatively based on the length and shape of the part. 10. An edge judging means judges an edge state based on pixel information of a line of interest and lines before and after the line of interest as a method of detecting the edge and the length of the edge. 10. The writing optical apparatus according to claim 9, wherein the position and the length of the edge are obtained from both ends in the scanning direction. 11. A correcting means for arranging a light source whose effective print pixel number blinks in accordance with an input image signal, and writing light from this light source on a photosensitive member collectively for each line to form a latent image. The writing optical device according to claim 1, wherein: