JPH03216680A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image forming apparatus that records an image using a light beam output from a light emitting section, and more specifically, relates to an image forming apparatus that records an image using a light beam output from a light emitting section. The present invention relates to an improved image forming apparatus.

[Conventional technology]

In recent years, DTP (disk top publishing,
For example, with the development of image forming devices such as printers (disk top word processors, etc.),
High resolution and multiple gradations are now required. In order to meet such demands, it is necessary to improve the reproducibility of minute dots.

However, when using minute dots, the uniformity of the dots improves as shown in Fig. 6 (b), but when the dots aggregate, the aggregation becomes poor, for example, as shown in Fig. 6 ( As shown in Figure 5(a), there is a problem that the gap at the end of the dot set becomes large, and conversely, if large dots are used for dot set, the gap at the end of the dot set increases as shown in Figure 5(a). Although the gap becomes smaller, the gap in Figure 5 (b
), there were problems in that the uniformity of the dots was poor and small dots could not be reproduced. Therefore,
In order to improve the reproducibility of minute dots 1 and to sufficiently express the dot set, consideration has been given to making the spot diameter (dot diameter) variable and using the spot diameter selectively. For example, as disclosed in Japanese Patent Application Laid-Open No. 63-265642, an image recording apparatus has been proposed which is capable of forming clear, high-quality images by switching the spot diameter of one light beam.

[Problem to be solved by the invention]

However, according to the image recording device disclosed in Japanese Patent Application Laid-Open No. 63-265642, by selectively using the spot diameter, for example, the spot diameter can be made smaller to improve the reproducibility of minute dots, and conversely, the spot diameter can be made larger. However, since the spot diameter of one light beam is switched, in other words, one laser diode is controlled and the spot diameter is changed, the spot diameter is changed. There was a problem with poor stability.

Furthermore, there was also the problem that it was not suitable for high-speed printing.

The present invention has been made in view of the above, and is capable of stably reproducing clear, well-balanced minute dots and thick lines, capable of high-speed printing, and capable of producing high-resolution, multi-gradation images. The purpose is to obtain.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an image forming apparatus that records an image using a light beam outputted from a light emitting section, which includes a light emitting means made up of a plurality of light emitting sections that output light beams with different spot shapes. An image forming apparatus is provided.

The present invention also provides an image forming apparatus that selectively uses light beams with different spot shapes.

Furthermore, the present invention provides an image forming apparatus that selectively uses light beams with different spot shapes by referring to information about the previous position of the dot of interest in the sub-scanning direction.

[Effect]

The light emitting means of the image forming apparatus of the present invention uses a plurality of light emitting sections to output light beams with different spot shapes, and selectively uses the plurality of light beams with different spot shapes to produce minute dots and thick lines. Reproduce.

〔Example〕

Hereinafter, the image forming apparatus of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of an image forming apparatus according to the present invention, and to simplify the explanation, only the configuration of an optical system (semiconductor laser light source device) which is a main part of the present invention is shown. In this embodiment, an example in which an rθ lens and a polygon mirror are used as a semiconductor laser light source device will be described.

The semiconductor laser light source device includes a first laser diode lot and a second laser diode 102 that output a light beam (laser beam), and reflects the light beams output from the first laser diode 101 and the second laser diode 102 in a predetermined direction. The first mirror 103 and the first mirror 10
A polygon mirror 104 scans the reflection direction of the light beam reflected from the second mirror 106 and the third mirror 10.
fθ lenses 105a and 105b incident on the first laser diode 101 and the second laser diode 102; The optical system controller 205 (see FIG. 2) controls the light emission of the second laser diode 102.

Note that the light beams of the first laser diode 101 and the second laser diode 102 are as shown in FIG. 3(a).
It is assumed that the first laser diode 101 has a large spot diameter (spot diameter Φ1 in the figure (a)), and the second laser diode 102 has a small spot diameter (spot diameter Φ2 in the figure (a)).

FIG. 2 is an explanatory diagram showing the flow of print data (image information). The print data input to the input buffer 201 is converted into a conversion table 2 under the control of the microprocessor 203.
02, each dot is converted into dot information in the bitmap format. Although the details are omitted, this dot information includes on/off information for each dot and information about whether to use a laser diode. At this time, focus on the dot immediately before the target dot, and if the previous dot is on, the dot diameter is large (i.e., the first laser diode 10
1 is used), and when it is off, information about a small dot diameter (that is, the second laser diode 102 is used) is provided. Thereafter, based on the information regarding the laser diodes of each tot, those using a large dot diameter are written to the first output buffer 204a, and those using a small dot diameter are written to the second output buffer 204b. Subsequently, under the control of the optical system control unit 105, the first laser diode 101 and the second laser diode 102 write data into the first output buffer 204a and the second output buffer 204b from the same position and at the same time, respectively. By starting, a latent image can be formed by combining a laser diode with a large spot diameter and a laser diode with a small spot diameter.

The operation of the above configuration will be explained.

Light beams selectively emitted from the first laser diode 101 and the second laser diode 102 are reflected by the first mirror 103 and enter the polygon mirror 104 . This light beam is scanned by a polygon mirror 104,
The second mirror 1 passes through the fθ lenses 105a and 105b.
06 and the third mirror 107. Second mirror 10
The light beam incident on the line 6 is sent to the first synchronization sensor 108a and the second synchronization sensor 108b, and is used to synchronize each line. As a result, temporal correction of the first laser diode 101 and the second laser diode 102 is performed, and writing can be started from the same position at the same time.
It is possible to prevent the laser diode 102 from shifting in the main scanning direction. Further, the light beam incident on the third mirror 107 is reflected to form an electrostatic latent image on a photoreceptor (not shown).

FIG. 3(b) shows a line formed using the two spot diameters mentioned above, and as shown in the figure, even in a line drawn using one dot, there are two lines: a line with a spot diameter Φ1 and a line with a spot diameter Φ2. It is possible to draw different types of lines, and it is possible to draw different sizes of thin lines.
Clear images can be formed.

Furthermore, as shown in FIG. 4(a), when drawing a thick line (or a dot cluster), the first laser diode 101 with a large spot diameter is selectively used to form an image. , it is possible to obtain a clear image by reducing the gap at the end of the dot set, and when reproducing minute dots, as shown in FIG. By selectively using the laser diode 102 to draw dots, a highly uniform image can be obtained.

As mentioned above, in the image forming apparatus of this embodiment, two laser diodes 1 each have a predetermined shaped spot.
Since 01 and 102 are physically switched for use, a stable spot shape can always be obtained and stable high-speed printing is possible.

In addition, since the shape and size of the dots can be varied, it is possible to freely reproduce clear, well-balanced minute dots and thick lines, resulting in high-resolution images and multi-gradation images. be able to.

Furthermore, in this embodiment, since the print data input to the input buffer 201 is converted into dot information by the conversion table 202 under the control of the microprocessor 203, the information regarding the first laser diode 101 and the second laser diode 102 is determined in advance. There is no need to generate and transmit information, and there is no need to increase the amount of transmitted information.

Incidentally, in this embodiment, the spot shapes are circular and oval, but are not particularly limited to these shapes.

[Effects of the Invention] As explained above, the image forming apparatus of the present invention records an image using a light beam output from a light emitting section, in which a plurality of light emitting units outputting light beams with different spot shapes is used. Equipped with a light-emitting means consisting of 3 parts, it is possible to stably reproduce fine dots and thick lines with good clarity, high-speed printing, and high-resolution, multi-gradation images. .

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the image forming apparatus of the present invention, FIG. 2 is an explanatory diagram showing the flow of print data (image information) of the image forming apparatus of the present invention, and FIG. Example 1
The light beams of the laser diode and the second laser diode are an explanatory diagram showing the spont shape, FIG. 3(b) is an explanatory diagram showing the lines drawn using the first laser diode and the second laser diode, and FIG. a) and (b) are explanatory diagrams showing an example of how to use two spots according to the embodiment, and the fifth
FIGS. 6A and 6B and FIGS. 6A and 6B are explanatory diagrams showing dot construction and dot uniformity in conventional image forming apparatuses. Explanation of symbols 101・----・First laser diode 1 0 2-
--・1 2nd laser diode 1 0 3-1 ---
1st mirror 1 0 4 --- Polygon mirror 1 0 5 a , 1 0 5 b --- fθ lens 1 0 6 --- 1 2nd mirror 107 107 ---
- 3rd mirror 1 0 8 a- - 1 - 1st synchronization sensor 1 0 8 b - - - 2nd synchronization sensor 2 [} 1 - -
1.Input buffer 202--1 Conversion table 2 0 3-------Microprocessor 204a
---1st output buffer 2 0 4 b--12nd output buffer 205 ---
Optical system control section

Claims (3)

[Claims] (1) An image forming apparatus that records an image using a light beam output from a light emitting section, characterized in that the image forming apparatus is equipped with a light emitting means consisting of a plurality of light emitting sections that output light beams with different spot shapes. . (2) The image forming apparatus according to claim 1, wherein the light beams having different spot shapes are selectively used. (3) The image forming apparatus according to claim 1, wherein the light beams having different spot shapes are selectively used with reference to information on the previous position of the dot of interest in the sub-scanning direction.