JPH0843752A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the resolution at the time of forming the image of a curve or an oblique line part. CONSTITUTION:This device is provided with a photoreceptor 10 forming an electrostatic latent image on its surface by receiving a laser beam, two laser transmitting parts 5 and 6 transmitting the laser beam to the photoreceptor 10, a polarizing lens 7 setting the intensity of the laser beam from the laser transmitting parts 5 and 6, a rotary polygon mirror 8 performing scanning with the laser beam in a main scanning direction, and a data correction means 2 correcting data to be printed in a horizontal direction, dividing corrected data and outputting the data to the laser transmitting parts 5 and 6. The laser transmitting parts 5 and 6 are arranged so that the laser beam on the photoreceptor 10 from one laser transmitting part 5 may be deviated by half dot from the laser beam from the other laser transmitting part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
In particular, it relates to an image forming apparatus that controls the resolution. The image forming apparatus according to the present invention is applied to a printer device, a facsimile device, and the like.

[0002]

2. Description of the Related Art A conventional image forming apparatus using a laser beam has only one laser sending section according to the present invention, and a rotary polygon mirror is used to scan the laser beam onto a photosensitive member.

In this technical field, there is provided a method for controlling the image quality of a recorded image by using an optical modulator for increasing / decreasing the energy intensity of laser light (for example, Japanese Patent Laid-Open No. 63-120556), gradation control and A method in which polarization scanning is performed a plurality of times for the purpose of improving resolution (for example, JP-A-62-35).
No. 766) has been proposed.

[0004]

However, this conventional laser type image forming apparatus has a disadvantage that when the image is formed on a sheet or the like, a slight jaggedness can be seen in a curved line or a slanted line portion.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of improving the disadvantages of the conventional example, and particularly improving the resolution at the time of forming an image of a curved line or a slanted line portion.
To that end.

[0006]

Therefore, in the present invention, a photoconductor which forms an electrostatic latent image on the surface by receiving a laser beam, and two laser sending parts which respectively send the laser beam to the photoconductor. A polarizing lens that sets the size of the laser light from these laser transmitters, a rotary polygon mirror that scans the laser light in the main scanning direction, and the input data to be printed is corrected in the horizontal direction. Data correction means for dividing the data and outputting the divided data to the two laser emission units, respectively, wherein the laser beam emitted from one of the laser emission units is the laser beam of the other laser emission unit. It is arranged so that it is offset by half a dot from This aims to achieve the above-mentioned object.

[0007]

In the present invention, the data correction means first corrects the input data to be printed, which is received from the host device or the like, in the horizontal direction. Next, the corrected data is divided and output to the two laser transmitters. The laser sending section outputs a laser beam corresponding to the corrected data to the photoconductor,
The polarization lens sets the size of this laser light. The photoconductor forms an electrostatic latent image on its surface by receiving laser light. At this time, since one laser sending unit is arranged so that the laser beam on the photoconductor from this laser sending unit is shifted from the laser beam of the other laser sending unit by half a dot, the horizontal direction is equivalent to a half dot. An image (electrostatic latent image) is formed on the photoconductor by increasing the resolution.

[0008]

The present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing the configuration of this embodiment. The image forming apparatus includes a photoconductor 10 that forms an electrostatic latent image on its surface by receiving laser light, two laser sending units 5 and 6 that send laser light to the photoconductor 10, and these laser sending units. A polarizing lens 7 for setting the size of the laser light from the parts 5, 6 and a rotary polygon mirror 8 for scanning the laser light in the main scanning direction.
And the data correction means 2 for correcting the input data 1 to be printed in the horizontal direction and dividing the corrected data and outputting the divided data to the two laser sending units 5 and 6, respectively. Further, the laser sending units 5 and 6 are arranged so that the laser light on the photoconductor 10 from one laser sending unit 5 is deviated from the laser light from the other laser sending unit 6 by half a dot.

Further, an f-θ lens 9 is installed between the rotary polygon mirror 8 and the photoconductor 10. The f-θ lens 9 is used to convert the laser beam from the rotating polygon mirror 8 into a constant-velocity polarized light at a constant velocity on the photoconductor 10.
Further, the f-θ lens 9 corrects a surface tilt that occurs in relation to the accuracy of each surface of the rotary polygon mirror 8.

The photoconductor 10 is formed on the photoconductor drum 11, and toner from a developing device (not shown) adheres to the image portion formed on the photoconductor 10, and the toner is fed from a predetermined paper carry-in mechanism. It is transferred to the recording paper 12 that is carried in.

Further, in the present embodiment, the two laser sending units 5 and 6 output the semiconductor laser light.
6 is adopted, and in this case, the two laser sending units 5,
Reference numeral 6 turns on / off the output of the semiconductor laser light according to the data output from the data correction means 2. That is, the data correction unit 2 performs correction to add or decrease half dots in the horizontal direction of the input data 1, and divides the corrected input data to the two laser transmitting units according to the correction of the half dots and transmits the divided input data. In response to this, the two laser transmitters 5 and 6 turn on / off the output of the semiconductor laser light based on the input data.

Further, as shown in FIG. 2, the data correction means 2 has a memory 3 for temporarily storing the input data 1.
And a control circuit 4 for correcting the input data 1 in the horizontal direction.

Next, the operation of the image forming apparatus according to this embodiment will be described. First, when the input data 1 for forming an image is received from the host device, the data correction unit 2 stores the data in the memory 3, and the control circuit 4 calculates the portion where the half dot 13 is required. Next, the data correction means 2 sends data to the laser sending section 5 and the laser sending section 6, respectively. The ON / OFF of the data signal is performed in each of the laser transmitters 5 and 6. The polarization lens 7 adjusts the size of the laser beam corresponding to this data, and directs the beam to a rotary polygon mirror 8 having several surfaces each having a length of one line. The laser sending unit 5 and the laser sending unit 6 output laser light to different positions on the rotary polygon mirror 8. The beamed laser light is scanned by the rotation of the rotary polygon mirror 8.
And is corrected through the f-θ lens 9. The respective laser beams from the laser transmission units 5 and 6 form data on the surface of the photoconductor 10 at positions shifted by half a dot.

As described above, according to the present embodiment, the data formed on the photoconductor 10 and imaged on the paper 12 by the rotation of the photoconductor drum 11 has half dots in the shaded portion of the image, as shown in FIG. The image is formed at the shifted position. As described above, in this embodiment, it is possible to eliminate the slight jaggedness of the shaded portion and improve the resolution.

[0015]

Since the present invention is constructed and functions as described above, according to this, the data correction means horizontally corrects the input data to be printed, which is received from the host device, and the corrected data. Is divided and is output to each of the two laser transmitting units, so that it is possible to generate data in which the jaggedness of a curved line or a shaded portion in the image is reduced. Furthermore, the two laser sending units are arranged so that the output of the laser light is shifted by half a dot, and the two laser sending units output the laser light corresponding to the corrected data to the photoconductor, An image (electrostatic latent image) having a resolution increased by half a dot can be formed on the photoconductor in the horizontal direction. As described above, it is possible to provide an image forming apparatus capable of improving the resolution at the time of forming an image of a curved line or a shaded portion.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a data correction means shown in FIG.

FIG. 3 is a block diagram showing an image formed by the present apparatus when the embodiment shown in FIG. 1 is applied.

[Explanation of symbols]

 1 Input Data 2 Data Correcting Means 3 Memory 4 Control Circuit 5 One Laser Sending Section 6 The Other Laser Sending Section 7 Polarizing Lens 8 Rotating Polygonal Mirror 9 f-θ Lens 10 Photoconductor 11 Photosensitive Drum 12 Paper

Claims (3)

[Claims] 1. A photoconductor that forms an electrostatic latent image on its surface by receiving a laser beam, two laser sending units that respectively send the laser beam to the photoconductor, and laser beams from these laser sending units. , A rotary lens that scans the laser beam in the main scanning direction, and horizontal correction of the input data to be printed, and the corrected data is divided to send the two lasers. And a laser correction unit that outputs data to each unit, and the laser transmission unit is arranged so that the laser beam on the photoconductor from one laser transmission unit deviates from the laser beam of the other laser transmission unit by half a dot. An image forming apparatus characterized by. 2. The image forming apparatus according to claim 1, wherein the two laser sending units output semiconductor laser light. 3. The image forming apparatus according to claim 2, wherein the two laser sending units turn on / off the output of the semiconductor laser light according to the data output from the data correction unit.