JPH0524256A - Exposure method and exposure apparatus - Google Patents

Abstract

(57) [Summary] [Object] To provide an exposure method and an exposure apparatus capable of making jaggies inconspicuous. In an image forming apparatus in which one pixel is formed by a plurality of times of light emission of the edge-emitting EL element 10, an inclination angle of an outline of an image based on print data with respect to a main scanning direction is determined with a predetermined angle as a boundary , and the inclination is determined. In the case where the angle is an inclination angle close to the main scanning direction, the edge emitting EL element 10 is selectively caused to emit light in units of pixels through which the outline passes, and the inclination angle is an inclination angle close to the sub scanning direction. In order to reduce the image area, the pulse width of the voltage applied to the edge-emitting EL element 10 is gradually reduced in units of pixels through which the outline passes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method and an exposure apparatus for forming an electrostatic latent image on a photoconductor based on electrophotography.

[0002]

2. Description of the Related Art Recently, a line head composed of a large number of edge emitting EL (electroluminescence) elements arranged in the main scanning direction is arranged opposite to a photoconductor, and the outer peripheral surface of the photoconductor is charged. A line printer has been developed in which an electrostatic latent image is formed by irradiating a charged portion with light from each end surface emitting EL element of a line head, and the electrostatic latent image is developed and transferred to a sheet. The edge emitting EL device of this line head is a device in which a thin film active layer made of zinc sulfide containing an active element is surrounded by a dielectric and electrodes are formed on both sides of this dielectric. It has characteristics of extremely high emission intensity and fast response. FIG. 8 shows a part of an image based on the print data, where x is the size of one pixel in the main scanning direction and y is the size in the sub-scanning direction, and the width of the edge emitting EL element in the main scanning direction is shown. Corresponds to x, and its thickness is a fraction thereof. Therefore, an electrostatic latent image of one pixel is formed by causing one edge emitting EL element to emit light a plurality of times during the process of rotating the photoconductor.

As shown in FIG. 8, the outline L of the image is inclined with respect to the main scanning direction depending on the print data, but as long as the image is formed on a pixel-by-pixel basis, it is impossible to bring its outline close to a straight line. There is a problem that the line contour of the electrostatic latent image becomes jagged, which is called jaggies.

Therefore, since the edge-emitting EL element has a flat shape having a large width in the main scanning direction and a small thickness in the sub-scanning direction, the edge emitting type EL element emits the edge surface according to the image area partitioned into outlines for each pixel. An exposure method has been considered in which a type EL element is caused to emit light selectively. That is, since one pixel is formed by a plurality of light emission, if an image formed by one light emission is a pixel component, one pixel is formed by a plurality of flat pixel components arranged in the sub-scanning direction. The degree of jaggies can be made inconspicuous by forming an image in units of one pixel component instead of in units of one pixel.

[0005]

As described above, since the edge emitting EL element has a flat shape with a small thickness in the sub-scanning direction, the method of forming an image in units of one pixel component is the main scanning. This is effective when the angle of the outline L with respect to the direction (horizontal direction) is small. However, as shown in FIG. 9, the angle of the outline L with respect to the main scanning direction is 4
If it exceeds 5 ° and is close to the sub-scanning direction (vertical direction),
Even if the number of times of light emission is set on a pixel-by-pixel basis, there are many image areas that extend outside the outline L, and there are many blank areas that are originally image areas inside the outline L, resulting in unevenness with respect to the outline L. It's impossible to make jaggies unnoticeable as it grows.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a large number of flat edge emitting EL elements each having a thickness in the sub-scanning direction smaller than a width in the main scanning direction are arranged in the main scanning direction so as to face a photoconductor. , The edge emitting EL in the process of rotating the photoconductor
In an image forming apparatus that forms an electrostatic latent image of one pixel by irradiating light from the element to the photoconductor a plurality of times, the inclination angle of the outline of the image based on the print data with respect to the main scanning direction is set to 45 °. The tilt angle close to the main scanning direction or the tilt angle close to the sub-scanning direction is determined separately. If the tilt angle is the tilt angle close to the main scanning direction, the outline passes through the pixel unit in accordance with the image area. When the edge-emitting EL element is selectively made to emit light and the tilt angle is close to the sub-scanning direction, the edge-emitting EL element is switched to the edge-emitting EL element in accordance with the reduction of the image area in pixel units through which the outline passes. The pulse width of the applied voltage was reduced stepwise.

[0007]

When the inclination angle of the outline of the image with respect to the main scanning direction is judged to be small at the boundary of 45 °,
By selectively emitting light from the edge-emitting EL element in accordance with the image area in units of pixels through which the outline passes, an image area protruding outside the outline and a blank area inside are utilized by utilizing the flat shape of the edge-emitting EL element. Can be minimized, so that jaggies can be made inconspicuous, and if it is determined that the inclination angle of the outline of the image with respect to the main scanning direction is large at 45 °, the pixels through which the outline passes By gradually reducing the voltage pulse width applied to the edge emitting EL element in accordance with the decrease of the image area in units, the ratio of the image area can be expressed in binary gradation in pixel units through which the outline passes. Yes, this makes visual jaggies less noticeable.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. First, FIG. 1 shows the structure of an exposure apparatus. A host computer 1, a data judgment circuit block 2 which is a data judgment means, and a data conversion circuit 3 are connected in series. The print data transferred from the host computer 1 is print data based on a bit matte or outline font, but in any case, the data of the inclination angle of the outline of the image with respect to the main scanning direction is included in this print data. Therefore, in the data determination circuit block 2, the inclination angle of the outline of the image in the main scanning direction is determined from the received print data by dividing the inclination angle close to the main scanning direction or the inclination angle close to the sub-scanning direction at the boundary of 45 °. The data judgment signal is output to the data conversion circuit 3 together with the print data. The data conversion circuit 3 determines a light-emission operation determining means for determining a light-emission operation of an edge-emitting EL element, which will be described later, according to an image region in pixel units through which the outline passes when the inclination angle is close to the main scanning direction. 4, when the tilt angle is close to the sub-scanning direction, the pulse width of the voltage applied to the edge emitting EL element is gradually reduced in accordance with the reduction of the image area in units of pixels through which the outline passes. And pulse changing means 5. The head control circuit 6 outputs the drive signal set by the light emission operation determining means 5 and the drive signal set by the pulse changing means 5 to a common driver 7 and a channel driver 8 which are drive units, respectively.
Reference numeral 9 denotes a line head, which is formed by arranging a large number of edge emitting EL elements 10 on a substrate (not shown) in the main scanning direction. These edge-emitting EL elements 10 are obtained by surrounding a thin film active layer made of zinc sulfide containing an active element with a dielectric, and forming a common electrode 11 and a channel electrode 12 on both sides of the dielectric. The common electrode 11 is connected to the common driver 7, and the channel electrode 12 is connected to the channel driver 8.

As illustrated in FIG. 5, the channel electrode 12
When a positive / negative symmetrical low voltage pulse V ₁ is applied to the common electrode 11 and a positive / negative symmetrical high voltage pulse V ₂ close to the threshold voltage ± V _TH is applied to the common electrode 11, a difference V ₂ −V ₁ between these pulses is applied to the end surface. It is applied to the light emitting EL element 10. Therefore, by controlling the synchronization of these pulses V ₁ and V ₂ ,
A light emitting state as shown in FIG. 5A and a non-light emitting state as shown in FIG. 5B are obtained.

Next, an actual exposure method will be described with reference to the flowchart of FIG. Based on the print data transferred from the host computer 1, the data judgment circuit block 2 has a tilt angle close to the main scanning direction or a tilt close to the sub scanning direction with the tilt angle of the outline of the image with respect to the main scanning direction being 45 °. Judgment is made according to angle, and the result of the judgment (data judgment signal) is output to the data conversion circuit 3 together with the print data. In the data conversion circuit 3, when the inclination angle is close to the main scanning direction, the light emitting operation determining unit 4 determines the light emitting operation of the edge emitting EL element 10 according to the image area in pixel units through which the outline passes. However, when the inclination angle is close to the sub-scanning direction, the pulse width of the voltage applied to the edge emitting EL element 10 is gradually reduced in accordance with the reduction of the image area in units of pixels through which the outline passes. .

FIG. 3 and FIG. 4 each show a part of an image based on the print data, and these images are examples in which an outline L inclined with respect to the main scanning direction is included. FIG. 3 is an example in which the outline L with respect to the main scanning direction is smaller than 45 ° and is close to the main scanning direction. At this time, the edge emitting EL element 10 is selectively driven on the basis of the light emission operation data set by the light emission operation determining unit 4, so that in the pixel passing through the outline, the pixel component of the pixel component is changed according to the ratio of the image area. The number can be reduced and the area of the image protruding outside the outline L can be minimized. Therefore, the jaggy can be made inconspicuous.

FIG. 4 shows an example in which the outline L with respect to the main scanning direction is larger than 45 ° and is close to the sub scanning direction. At this time, a pulse is applied to the edge emitting EL element 10 based on the pulse width set by the pulse changing means 5.
FIG. 6 is an example of a timing chart showing a pulse applied to the edge-emitting EL device 10 that exceeds a threshold value on the vertical axis and takes a time to form one pixel on the horizontal axis. It shows a state in which the pulse width is gradually shortened as is decreased. 1 formed at this time
The pixel image is as shown in FIG. 7, and the shaded area is the exposed area (image area).

Therefore, as shown in FIG. 4, in the pixels through which the outline L passes, as the image area decreases, the edge-emitting EL element 10 intermittently emits light by the above-described method, so that the image area is increased for each pixel. Can be represented by binary gradation. Therefore,
You can make the jaggies invisible visually.

Incidentally, as shown in FIG. 6, if a pulse is intermittently applied during the formation of one pixel, afterglow light is emitted from the edge emitting EL element 10 after the pulse has fallen. The method is suitable for exposure systems with relatively long emission cycles.

[0015]

According to the present invention, a large number of flat edge emitting EL elements having a thickness smaller in the sub-scanning direction than in the main scanning direction are arranged in the main scanning direction so as to be opposed to the photoconductor. In an image forming apparatus that forms an electrostatic latent image of one pixel by irradiating the photosensitive member with light a plurality of times from the edge-emitting EL element in the process of rotating the image, main scanning of an outline of an image based on print data. The tilt angle with respect to the direction is determined by dividing it by 45 degrees as a tilt angle close to the main scanning direction or a tilt angle close to the sub-scanning direction. If the tilt angle is close to the main scanning direction, the outline is determined. When the inclination angle is an inclination angle close to the sub-scanning direction, the edge area emission type EL element is selectively caused to emit light in a pixel unit through which the outline passes, and an image area is obtained in a pixel unit through which the outline passes. Said end emission type EL according to the reduction
Since the pulse width of the voltage applied to the element is reduced stepwise, if it is determined that the inclination angle of the outline of the image with respect to the main scanning direction is small at 45 °, the pixel unit of the outline passes through. By selectively causing the edge-emitting EL element to emit light according to the image area,
By utilizing the flat shape of the edge emitting EL element, the image area protruding to the outside of the outline and the blank area on the inside can be minimized, whereby the jaggies can be made inconspicuous and in the main scanning direction. When it is determined that the inclination angle of the outline of the image is large at the boundary of 45 °, the voltage pulse width to be applied to the edge emitting EL element is stepwise according to the decrease of the image area in units of pixels through which the outline passes. By making it smaller, the ratio of the image area can be expressed in binary gradation in units of pixels through which the outline passes, which has the effect of making visual jaggies less noticeable.

[Brief description of drawings]

FIG. 1 is an electronic circuit diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart thereof.

FIG. 3 is an explanatory diagram showing a part of an image converted from the print data.

FIG. 4 is an explanatory diagram showing a part of an image converted from the print data.

FIG. 5 is a timing chart of voltage pulses applied to the common electrode and the channel electrode.

FIG. 6 is a timing chart showing a state in which the pulse width applied to the edge emitting EL element is changed according to the reduction of the image area of one pixel.

FIG. 7 is an explanatory diagram showing an image of one pixel formed when the pulse width is changed.

FIG. 8 is an explanatory diagram showing a part of an image based on conventional print data.

FIG. 9 is an explanatory diagram showing a part of an image converted from conventional print data.

[Explanation of symbols]

2 Data judgment means 4 Light emitting operation determining means 5 pulse changing means 7,8 Drive 10 Edge emitting EL device

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[Procedure amendment]

[Submission date] June 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Patent application title: Exposure method and exposure apparatus

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method and an exposure apparatus for forming an electrostatic latent image on a photoconductor based on electrophotography.

[0002]

2. Description of the Related Art Recently, a line head composed of a large number of edge emitting EL (electroluminescence) elements arranged in the main scanning direction is arranged opposite to a photoconductor, and the outer peripheral surface of the photoconductor is charged. A line printer has been developed in which an electrostatic latent image is formed by irradiating a charged portion with light from each end surface emitting EL element of a line head, and the electrostatic latent image is developed and transferred to a sheet. The edge emitting EL device of this line head is a device in which a thin film active layer made of zinc sulfide containing an active element is surrounded by a dielectric and electrodes are formed on both sides of this dielectric. It has characteristics of extremely high emission intensity and fast response. FIG. 8 shows a part of an image based on the print data, where x is the size of one pixel in the main scanning direction and y is the size in the sub-scanning direction, and the width of the edge emitting EL element in the main scanning direction is shown. Corresponds to x, and its thickness is a fraction thereof. Therefore, an electrostatic latent image of one pixel is formed by causing one edge emitting EL element to emit light a plurality of times during the process of rotating the photoconductor.

As shown in FIG. 8, the outline L of the image is inclined with respect to the main scanning direction depending on the print data, but as long as the image is formed on a pixel-by-pixel basis, it is impossible to bring its outline close to a straight line. There is a problem that the line contour of the electrostatic latent image becomes jagged, which is called jaggies.

Therefore, since the light emitted from the edge emitting EL element has a flat shape with a large width in the main scanning direction and a small thickness in the sub scanning direction, it is partitioned into outlines for each pixel. An exposure method has been considered in which an edge-emitting EL element is selectively caused to emit light in accordance with an image area. That is, since one pixel is formed by a plurality of light emission, if an image formed by one light emission is a pixel component, one pixel is formed by a plurality of flat pixel components arranged in the sub-scanning direction. The degree of jaggies can be made inconspicuous by forming an image in units of one pixel component instead of in units of one pixel.

[0005]

As described above, since the light emitted from the edge emitting EL element has a flat shape with a small thickness in the sub-scanning direction, a method of forming an image in units of one pixel constituent element is not possible. , Is effective when the angle of the outline L with respect to the main scanning direction (horizontal direction) is small. However, as shown in FIG. 9, when the angle of the outline L with respect to the main scanning direction exceeds 45 ° and is close to the sub-scanning direction (vertical direction), even if the number of times of light emission is set per pixel, the outline There are many image areas that extend outside L, and
Originally inside the outline L, the blank area of the portion which is the image area is increased and the unevenness is increased with respect to the outline L, and it is impossible to make the jaggies inconspicuous.

[0006]

According to the present invention, a large number of edge emitting EL elements emitting flat light having a thickness in the sub-scanning direction smaller than a width in the main scanning direction are arranged in the main scanning direction. And an image forming apparatus that forms an electrostatic latent image of one pixel by irradiating the photoconductor with light from the edge-emitting EL element a plurality of times in a process of rotating the photoconductor, determines separately the inclination angle close to or near the inclination angle or the sub-scanning direction in the main scanning direction a predetermined inclination angle against the main scanning direction of the outline of the image based on the print data as the boundary, the inclination angle of the main scanning direction In the case of an inclination angle close to, the edge emitting EL elements are selectively caused to emit light in accordance with the image area in pixel units through which the outline passes,
When the tilt angle is close to the sub-scanning direction,
A pulse that exceeds the threshold voltage to the edge-emitting EL element according to the reduction of the image area in units of pixels through which the outline passes
Was gradually reduced and applied .

[0007]

When it is judged that the inclination angle of the outline of the image with respect to the main scanning direction is small at a predetermined angle as a boundary , the edge-emitting EL elements are selectively emitted according to the image area in units of pixels through which the outline passes. By making use of the flat shape of the edge emitting EL element, the image area protruding to the outside of the outline and the blank area on the inside can be minimized, whereby the jaggies can be made inconspicuous, When it is determined that the inclination angle of the outline of the image with respect to the main scanning direction is large with a predetermined angle as a boundary , the edge emission type EL element exceeds the threshold voltage in accordance with the decrease of the image area in units of pixels through which the outline passes.
By gradually reducing the number of pulses and applying
The ratio of the image area can be expressed in binary gradation in units of pixels through which the outline passes, and thereby, jaggies can be made visually inconspicuous.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. First, FIG. 1 shows the structure of an exposure apparatus. A host computer 1, a data judgment circuit block 2 which is a data judgment means, and a data conversion circuit 3 are connected in series. The print data transferred from the host computer 1
The print data is based on the bitmap or outline font, but in any case, the data of the inclination angle of the outline of the image with respect to the main scanning direction is included in the print data. Therefore, the data judgment circuit block 2 determines whether the inclination angle of the outline of the image in the main scanning direction from the received print data is close to the main scanning direction with a predetermined angle (for example, about 45 °) as a boundary . It is possible to make a determination by dividing the inclination angle close to the sub-scanning direction, and the data determination signal is output to the data conversion circuit 3 together with the print data. The data conversion circuit 3 determines a light-emission operation determining means for determining a light-emission operation of an edge-emitting EL element, which will be described later, according to an image region in pixel units through which the outline passes when the inclination angle is close to the main scanning direction. 4 and in the case where the tilt angle is close to the sub-scanning direction, the number of pulses exceeding the threshold voltage is gradually increased in the edge emission type EL element in accordance with the decrease of the image area in units of pixels through which the outline passes.
And a pulse changing means 5 for applying a reduced voltage . The head control circuit 6 outputs the drive signal set by the light emission operation determining means 5 and the drive signal set by the pulse changing means 5 to a common driver 7 and a channel driver 8 which are drive units, respectively. Reference numeral 9 denotes a line head, and this line head 9 has a large number of edge emitting EL elements 1
It is formed by arranging 0s on the substrate (not shown) in the main scanning direction. These edge emitting EL elements 10
Is a thin-film active layer made of zinc sulfide or the like containing an active element surrounded by a dielectric, and a common electrode 11 and a channel electrode 12 are formed on both surfaces of this dielectric.
1 is connected to the common driver 7, and the channel electrode 12 is connected to the channel driver 8.

As illustrated in FIG. 5, the channel electrode 12
When a positive / negative symmetrical low voltage pulse V ₁ is applied to the common electrode 11 and a positive / negative symmetrical high voltage pulse V ₂ close to the threshold voltage ± V _TH is applied to the common electrode 11, a difference V ₂ −V ₁ between these pulses is applied to the end surface. It is applied to the light emitting EL element 10. Therefore, by controlling the synchronization of these pulses V ₁ and V ₂ ,
A light emitting state as shown in FIG. 5A and a non-light emitting state as shown in FIG. 5B are obtained.

Next, an actual exposure method will be described with reference to the flowchart of FIG. Based on the print data transferred from the host computer 1, the data judgment circuit block 2 has an inclination angle close to the main scanning direction or an inclination angle close to the sub-scanning direction with a predetermined inclination angle with respect to the main scanning direction of the outline of the image as a boundary. Judgment is made by dividing into crabs, and the result of the judgment (data judgment signal) is output to the data conversion circuit 3 together with the print data. In the data conversion circuit 3, when the inclination angle is close to the main scanning direction, the light emitting operation determining unit 4 determines the light emitting operation of the edge emitting EL element 10 according to the image area in pixel units through which the outline passes. However, if the tilt angle is close to the sub-scanning direction, the edge-emitting EL element 10 will exceed the threshold voltage in accordance with the decrease of the image area in units of pixels through which the outline passes.
The number of looses is gradually reduced and applied .

FIG. 3 and FIG. 4 each show a part of an image based on the print data, and these images are examples in which an outline L inclined with respect to the main scanning direction is included. In FIG. 3, the outline L in the main scanning direction is
In this example, the angle is smaller than a predetermined angle (for example, about 45 °) and is close to the main scanning direction. At this time, the edge emitting EL element 10 is selectively driven on the basis of the light emission operation data set by the light emission operation determining unit 4, so that in the pixel passing through the outline, the pixel component of the pixel component is changed according to the ratio of the image area. The number can be reduced and the area of the image protruding outside the outline L can be minimized. Therefore, the jaggy can be made inconspicuous.

FIG. 4 shows an example in which the outline L with respect to the main scanning direction is larger than a predetermined angle (for example, about 45 °) and is close to the sub scanning direction. At this time, based on the pulse width set by the pulse changing means 5, the edge emitting EL element 10 is
Apply a pulse to. In FIG. 6, the horizontal axis indicates the time for forming one pixel, and the vertical axis indicates the emission and non-emission of the edge-emitting EL device 10.
An example of a timing chart showing light shows a state in which the pulse width is gradually shortened as the ratio of the image area in the pixel passing through the outline decreases. The one-pixel image formed at this time is as shown in FIG. 7, and the shaded portion is the exposed portion (image area).

Therefore, as shown in FIG. 4, in the pixels through which the outline L passes, as the image area decreases, the edge-emitting EL element 10 intermittently emits light by the above-described method, so that the image area is increased for each pixel. Can be represented by binary gradation. Therefore,
You can make the jaggies invisible visually.

The predetermined angle is about 45 °.
However, the inclination of the outline L is based on 30 ° to 60 °
A pattern is applied to the edge emitting EL element 10 by judging the oblique angle.
Even if the number of lus was adjusted, good results were obtained. In addition, FIG.
When a pulse is applied intermittently during the formation of one pixel, as shown in FIG.
Since the afterglow is emitted from the element 10, such a method is
It is suitable for exposure systems with a relatively long light emission cycle.

[0015]

According to the present invention, a large number of edge emitting type E emitting flat light having a thickness in the sub-scanning direction smaller than a width in the main scanning direction.
The L elements are arranged in the main scanning direction and are arranged so as to face the photoconductor, and in the process of rotating the photoconductor, light is emitted from the edge emitting EL device to the photoconductor a plurality of times to electrostatically charge one pixel. In an image forming apparatus that forms a latent image, the outline of an image based on print data is aligned in the main scanning direction .
The predetermined inclination angle is used as a boundary to determine whether the inclination angle is close to the main scanning direction or the sub-scanning direction. If the inclination angle is close to the main scanning direction, the outline passes. In the case where the edge emitting EL element is selectively caused to emit light in pixel units according to the image area and the inclination angle is an inclination angle close to the sub-scanning direction, the outline area passes in pixel units in accordance with the decrease in the image area. The edge-emitting EL device with a stepwise change in the number of pulses exceeding the threshold voltage.
Since the application is made small, if the inclination angle of the outline of the image with respect to the main scanning direction is determined to be small at a predetermined angle as a boundary , the edge-emitting type EL according to the image region in pixel units through which the outline passes. By selectively emitting light from the element, the flat shape of the edge-emitting EL element can be utilized to minimize the image area protruding outside the outline and the blank area inside, thereby making jaggies conspicuous. When it is determined that the inclination angle of the outline of the image with respect to the main scanning direction is large with a predetermined angle as a boundary, the end surface is reduced according to the decrease of the image area in pixel units through which the outline passes. Emissive type E
Reduce the number of pulses that exceed the threshold voltage to the L element stepwise
Then, the ratio of the image area can be expressed in binary gradation in units of pixels through which the outline passes, which has the effect of making jaggies less visible.

[Brief description of drawings]

FIG. 1 is an electronic circuit diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart thereof.

FIG. 3 is an explanatory diagram showing a part of an image converted from the print data.

FIG. 4 is an explanatory diagram showing a part of an image converted from the print data.

FIG. 5 is a timing chart of voltage pulses applied to the common electrode and the channel electrode.

FIG. 6 shows a stepwise reduction in the number of pulses exceeding the threshold voltage in the edge-emitting EL element in accordance with the decrease in the image area of one pixel.
It is a timing chart which shows the state which applied it .

FIG. 7 is an explanatory diagram showing an image of one pixel formed when the pulse width is changed.

FIG. 8 is an explanatory diagram showing a part of an image based on conventional print data.

FIG. 9 is an explanatory diagram showing a part of an image converted from conventional print data.

[Explanation of symbols] 2 Data judgment means 4 Light emitting operation determining means 5 pulse changing means 7,8 Drive 10 Edge emitting EL device

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H04N 1/036 A 9070-5C

Claims (2)

[Claims] 1. A process in which a large number of flat end-face emitting EL elements having a smaller thickness in the sub-scanning direction than in the main-scanning direction are arranged in the main scanning direction so as to face the photoconductor and the photoconductor is rotated. In an image forming apparatus that forms an electrostatic latent image of one pixel by irradiating the photosensitive member with light from the edge emitting EL element a plurality of times, the inclination angle of the outline of the image based on the print data with respect to the main scanning direction. 45 °
It is determined by dividing the inclination angle close to the main scanning direction or the inclination angle close to the sub-scanning direction with the boundary as the boundary, and when the inclination angle is the inclination angle close to the main scanning direction
In a case where the edge-emitting EL element is selectively caused to emit light in a pixel unit through which the outline passes and the tilt angle is a tilt angle close to the sub-scanning direction, the image region in a pixel unit through which the outline passes The exposure method is characterized in that the pulse width of the voltage applied to the edge emitting EL element is reduced stepwise according to the decrease of 2. A process in which a large number of flat end-face emitting EL elements having a thickness smaller in the sub-scanning direction than in the main scanning direction are arranged in the main scanning direction so as to face the photoconductor and the photoconductor is rotated. In an image forming apparatus that forms an electrostatic latent image of one pixel by irradiating the photosensitive member with light from the edge emitting EL element a plurality of times, the inclination angle of the outline of the image based on the print data with respect to the main scanning direction. 45 °
Data determining means for determining whether the tilt angle is close to the main scanning direction or the tilt angle close to the sub-scanning direction, and a pixel unit through which the outline passes when the tilt angle is a tilt angle close to the main scanning direction. In the light emitting operation determining means for determining the light emitting operation of the edge emitting EL element according to the image area, and when the inclination angle is an inclination angle close to the sub-scanning direction, the image area is reduced in units of pixels through which the outline passes. Pulse changing means for gradually reducing the pulse width of the voltage applied to the edge emitting EL element according to the above, and the edge emitting light is provided to the drive unit connected to the light emitting operation determining means and the pulse changing means. An exposure apparatus, characterized in that each type EL element is connected.