JPH1065883A - Optical writing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the performance of the whole optical writing device and to reduce the size and the cost of the device by arranging at least one pair of a light beam scanning writing device and a fixed light writing device in series in the main scanning direction and allowing the sum of the scanning width of respective optical writing devices on an image surface approximately to coincide with the scanning width of the whole optical writing device. SOLUTION: The solid-state optical writing device 7, the optical beam scanning writing device 4 and the device 7 are successively arranged in series in the main scanning direction. The optical beam scanning writing device 4 executes scanning for the writing of an electrostatic latent image within scanning width (a) from the right side of the main scanning direction to the left side. Then the device 7 executes scanning for the writing of a register mark within scanning width (b) by the same procedure. Then the device 4 writes an electrostatic latent image within the width (a) by the same procedure. In this case the total scanning width of the width (a) and the width (b) coincides with the whole scanning width (c) on the image face of a photoreceptor. The writing devices 4, 7 respectively execute write scanning only within the partial scanning width (a), (b) of the whole scanning width (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical writing device suitable for the field of printing, and can be applied to a digital writing device such as a digital copying machine, a facsimile, a laser printer, and the like.

[0002]

2. Description of the Related Art In recent years, optical writing apparatuses have been able to form images suitable for various types of printing by improving their performance. Light beam scanning and writing devices that can be used in the printing field are also in high demand. In order to use the light beam scanning writer in the printing field, it is necessary to increase the writing width, as described later in detail. Due to limitations, the use of multiple light beam scanning and writing devices is conceivable.

A conventional example using a plurality of light beam scanning / writing devices is disclosed in Japanese Patent Publication No. 4-55282. This is because a light beam writing system composed of a light source, an imaging lens, a mirror, and the like is installed in parallel in the sub-scanning direction, and a light beam from each light source is scanned through one rotating polygon mirror, and By making the curvature of field and the direction of curvature of each of the scanning lines formed accordingly substantially the same, it is possible to prevent color misregistration of a color printer.
Therefore, this conventional example is not intended to increase the writing width.

Another conventional example using a plurality of light beam scanning / writing devices is disclosed in Japanese Patent Publication No. 4-16766. This is because a plurality of sets of light beam writing systems including a light source, an imaging lens, a mirror, and the like are installed in series in the main scanning direction, and light beams from the respective light sources are transmitted to different reflection surfaces of one rotary polygon mirror. When the scanning light is made to be the same straight line on the scanning image plane, and the respective scanning widths are l and m and the scanning width of the entire scanning optical system is n, n = l + m. By doing so, it is possible to have a small size, a wide scanning width and a high resolution.

[0005]

In a light beam scanning writing apparatus used in the printing field, a register mark or the like is printed outside an image area for positioning at the time of cutting. For example, if the image area is the A3 size, the mark mark is located outside the A3 size image area with a writing width (scanning width) called “A3 registration mark” or “A3 stretch” larger than the width of the A3 size. Etc. are printed.

On the other hand, in the conventional light beam scanning writing apparatus for a digital copying machine as described above, the writing width (scanning width) is determined by JIS dimensions like A3 and A4. It is not possible to print a registration mark or the like for positioning at the time of cutting outside the image area. That is, the writing width of the light beam scanning writing device for the digital copying machine is set to be the same as the image area width. Therefore, the conventional light beam scanning writer for a digital copying machine cannot be used as a light beam scanning writer used in the printing field. Therefore, as described in Japanese Patent Publication No. 4-16766, a plurality of light beam scanning / writing devices may be used, but the space occupied by the plurality of light beam scanning / writing devices increases. However, there is a problem that the entire apparatus becomes large. In addition, it is conceivable to redesign the optical beam scanning writing device so that the scanning width is increased. However, it is difficult to secure the image performance, and there is a problem that the device is increased in size.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has been made by adding another optical writing device to a light beam scanning writing device for a digital copying machine. It is an object of the present invention to provide an optical writing device that can be used as a light beam scanning writing device used in the field and can be downsized.

[0008]

According to the first aspect of the present invention,
A light source for generating a light beam, a light deflector for deflecting the light beam, a light beam scanning and writing device having an imaging optical system for forming an image of the light beam, and a plurality of light sources for generating a plurality of light beams in an array And a solid-state optical writing device having an imaging optical system for forming an image of a light beam from the array light source. The light beam scanning writing device and the solid-state optical writing device At least one set of the above is arranged in series in the main scanning direction, and the sum of the scanning widths of the respective writing devices on the image plane is substantially equal to the scanning width of the entire optical writing device.

The invention according to claim 2 is characterized in that the light beam scanning writing device and the fixed optical writing device have the same writing density.

The invention according to claim 3 is characterized in that the writing density of the light beam scanning writing device and that of the fixed optical writing device are different.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an optical writing apparatus according to the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a light source that emits a divergent light beam. As the light source 1, a laser diode (LD), a light emitting diode (LED), or the like is used. The divergent light beam emitted from the light source 1 passes through a coupling lens (not shown) and a linear image forming element, and is emitted toward the optical deflector 2. Line images are connected. The light deflector 2 deflects an incident light beam at a constant angular velocity.

The light reflected by the deflecting / reflecting surface of the optical deflector 2 passes through an imaging optical system 3 having an fθ lens, and is deflected at a constant angular velocity by the optical deflector 2. Optical scanning is performed on the image plane 8 of the photoconductor at a constant speed. The light source 1, the deflector 2, and the imaging optical system 3 form a light beam scanning and writing device 4.

In FIG. 1, reference symbol a indicates a scanning width in which the light beam scanning writing device 4 performs optical scanning. The scanning width a is a central portion of the entire scanning width c on the image plane 8 of the photosensitive member, and an electrostatic latent image corresponding to the document image is formed at the scanning width a.

1 and 3, reference numeral 5 denotes an array light source in which a plurality of light sources are arranged in an array (lattice shape). Reference numeral 6 denotes an image forming optical system for forming an image of the light beam emitted from the array light source 5. The image forming optical system 6 includes a convergent light transmission path (selfoc lens).
It is formed with. In this SELFOC lens, since the refractive index decreases in a quadratic curve from the optical axis in the radial direction, the incident light beam passes through a spiral or sinusoidal optical path with a pitch P about the optical axis. . Therefore, if the length is properly selected, various lens functions such as convergence, divergence, and parallelism can be obtained. However, if the length is P / 2 to P, an equal-size erect real image can be obtained. Can be used. That is, if this selfoc lens is used in a copying machine or the like, the conjugate length is very short, and no folding reflecting mirror is required, so that the imaging system can be made compact. The image forming optical system 6 formed by the selfoc lens and the array light source 5 are coupled to each other so that a light beam emitted from the array light source 5 can pass through the image forming optical system 6 to perform solid-state optical writing. The device 7 is formed.

As shown in FIG. 1, the solid-state optical writing devices 7, 7 are arranged in series so as to sandwich the light beam scanning writing device 4 in the main scanning direction. That is, the solid-state optical writing device 7, the light beam scanning writing device 4,
One or more sets of each writing device are installed so as to be the solid-state optical writing device 7.

In the example of FIG. 1, the solid-state optical writing device 7, the light beam scanning writing device 4, and the solid-state optical writing device 7 are arranged in series in the main scanning direction. As described above, the light beam scanning writer 4, the solid-state optical writer 7, and the light beam scanning writer 4 may be arranged in series in the main scanning direction. Alternatively, the light beam scanning writing device 4 and the solid-state optical writing device 7 may be arranged in series one by one.

In the example of FIG. 1, the solid-state optical writing devices 7, 7 are for printing a register mark or the like for positioning at the time of cutting outside the image area. The symbol b is
The scanning width of the solid-state optical writing device 7 for optical scanning is shown. The scanning width b is a part of the entire scanning width c on the image plane 8 of the photoconductor, and an electrostatic latent image corresponding to a registration mark or the like for positioning is formed in the scanning width b. .

In the embodiment shown in FIG. 1, the scanning width a for optical scanning by the light beam scanning writing device 4 and the scanning widths b and b for optical scanning by the solid-state optical writing devices 7 and 7 are the total. The scanning width matches the entire scanning width c on the image plane 8 of the photoconductor. That is, the entire scanning width c on the image plane 8 of the photoconductor is b + a
+ B. Further, in the embodiment shown in FIG. 4, the scanning widths a and a of the optical beam scanning writing device 4 for optical scanning and the total scanning width of the solid-state optical writing device 7b are different from each other on the image plane 8 of the photosensitive member. This corresponds to the entire scanning width c. That is, the entire scanning width c on the image plane 8 of the photoconductor is equal to a + b + a.

Next, the operation of the present invention will be described. In the case of the embodiment shown in FIG. 1, first, the solid-state optical writing device 7 (right side in FIG. 1) performs writing scanning of a register mark or the like within a scanning width b from the right side to the left side in the main scanning direction. Done. Simultaneously with the completion of the writing, the light beam scanning writing device 4 performs writing scanning of the electrostatic latent image corresponding to the original image within the scanning width a from the right side to the left side in the main scanning direction. At the same time as the completion of this writing scan,
By the solid-state optical writing device 7 (left side in FIG. 1),
The writing scan of the register mark or the like is performed within the scanning width b from the right side to the left side in the main scanning direction. In this way, the writing scan of one line in the main scanning direction is completed. When the writing scan of one line is completed, the photoconductor rotates in the sub-scanning direction, and the writing scan of the second line in the sub-scanning direction is performed in the same manner as described above, and this writing scan is repeated in the sub-scanning direction. Thus, a series of writing scans is completed.

In the case of the embodiment shown in FIG. 4, first, the light beam scanning writing device 4 (right side in FIG. 4) converts a document image within a scanning width a from the right side to the left side in the main scanning direction. The corresponding electrostatic latent image is written and scanned. At the same time as the completion of the writing, the solid-state optical writing device 7 performs the writing scan of the registration mark or the like within the scanning width b from the right side to the left side in the main scanning direction. At the same time as the completion of the writing scan, the light beam scanning writing device 4 (left side in FIG. 4) sets the electrostatic latent image corresponding to the original image within the scanning width a from the right side to the left side in the main scanning direction. A write scan is performed. When the writing scan of one line is completed in this way, the writing scan of the second line in the sub-scanning direction is performed in the same manner as described above, and this writing scan is repeated in the sub-scanning direction, so that a series of The writing scan ends.

In the above description, the case of using for printing is described, and the writing scan of the electrostatic latent image corresponding to the original image is performed by the light beam scanning writing device 4 within the scanning width a. The solid-state optical writing scan 7 performs the writing scan of the register mark or the like within the scanning width b.
When used for a copying machine, the light beam scanning / writing device 4
By using both the solid-state optical writing scanning 7 and the solid-state optical writing scanning, the writing scanning of the electrostatic latent image corresponding to the original image is performed within the scanning width c in the same manner as described above.

Here, the scanning width of the light beam scanning writing device 4 and the solid-state optical writing device 7 will be described. In the light beam scanning and writing device 4, the scanning width on the image plane is determined by the relationship between the focal length of the imaging lens (imaging optical system) and the angle of view. In other words, when the scanning width is fixed, if an imaging lens having a long focal length is arranged, the angle of view becomes small, while if an imaging lens having a short focal length is arranged, the angle of view becomes large. I will.

Generally, if the angle of view is reduced, the performance of the entire apparatus can be improved, and there is an advantage that components can be reduced. However, when the angle of view is reduced, an imaging lens having a long focal length must be provided in order to satisfy a desired scanning width, and there is a disadvantage that the entire apparatus becomes large.

On the other hand, in the solid-state optical writing device 7, the scanning width on the image plane is the length of the solid-state optical writing device 7 in the main scanning direction,
That is, it is determined by the length of the array light source 5 and the imaging optical system 6 in the main scanning direction. Therefore, there is no problem of the focal length and the angle of view as described above. However, if the length of the solid-state optical writing device 7 in the main scanning direction is increased, the cost increases and the entire device becomes large. There is a problem that it becomes.

However, according to the above-described embodiment, the light beam scanning writing device 4 performs the writing scan only for a partial scanning width a of the entire scanning width c on the image plane 8 of the photosensitive member. This is done so that the angle of view can be reduced and the focal length can be minimized. In addition, the solid-state optical writing device 7 is configured to perform writing scanning only for a part of the entire scanning width c on the image plane 8 of the photoconductor, and thus, the solid-state optical writing device. Since it is sufficient to provide the length in the main scanning direction for the scanning width b, the size of the entire apparatus can be reduced, and the cost can be reduced.

Accordingly, the present invention satisfies the desired scanning width by combining the advantages of the light beam scanning writing device 4 and the solid-state writing device 7 as described above,
It is possible to improve the performance of the entire apparatus, reduce the size, and further reduce the cost. Further, the present invention can be used not only for digital copying machines but also for printing.

When used for a copying machine, the writing density of the light beam scanning writing device 4 and the writing density of the solid-state writing device 7 are made the same, so that the The printing quality can be made uniform and good within the scanning width c.

When used for printing, the writing density of the light beam scanning writing device 4 and the writing density of the solid-state writing device 7 do not have to be the same. That is, the writing density of the solid-state writing device 7 may be lower than the writing density of the light beam scanning writing device 4. The solid-state optical writing device 7
Is for printing a registration mark or the like for positioning during cutting outside the image area (scanning width b).
This is because there is no problem even if the print quality in the scan width b is inferior to the print quality in the image area (scan width a). By doing so, the cost can be reduced.

[0029]

According to the first aspect of the invention, at least one set of a light beam scanning writing device and a solid-state optical writing device are arranged in series in the main scanning direction, and each optical writing on an image plane is performed. Since the sum of the scanning widths of the device is made substantially equal to the scanning width of the entire optical writing device, it is possible to improve the performance of the entire device, reduce the size, and further reduce the cost. Further, it can be used not only for digital copying machines but also for printing.

According to the second aspect of the present invention, since the writing density of the light beam scanning writing device and the fixed optical writing device is the same, the print quality on the image plane is uniform and good. Can be

According to the third aspect of the present invention, the writing density of the light beam scanning writing device is different from that of the fixed optical writing device. The writing density of the writing device can be made lower than the writing density of the light beam scanning writing device, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an optical layout diagram showing an embodiment of an optical writing device according to the present invention.

FIG. 2 is an optical layout diagram showing an example of a light beam scanning writing apparatus applicable to the present invention.

FIG. 3 is an optical layout diagram showing an example of a fixed optical writing device applicable to the present invention.

FIG. 4 is an optical layout diagram showing another example of the embodiment of the optical writing device according to the present invention.

[Description of Signs] 1 light source 2 optical deflector 3 imaging optical system 4 light beam scanning / writing device 5 array light source 6 imaging optical system 7 solid-state optical writing device 8 image plane

Claims (3)

[Claims] 1. A light source for generating a light beam, a light deflector for deflecting the light beam, a light beam scanning and writing device having an imaging optical system for forming an image of the light beam, and a plurality of light beams for generating a plurality of light beams An array light source in which the light sources are arranged in an array, and a solid-state optical writing device having an image forming optical system for forming an image of a light beam from the array light source. At least one or more sets with the solid-state optical writing device are arranged in series in the main scanning direction, and the sum of the scanning widths of the respective writing devices on the image plane is made substantially equal to the scanning width of the entire optical writing device. An optical writing device characterized by the following. 2. The optical writing apparatus according to claim 1, wherein said optical beam scanning writing apparatus and said fixed optical writing apparatus have the same writing density. 3. The optical writing apparatus according to claim 1, wherein said optical beam scanning writing apparatus and said fixed optical writing apparatus have different writing densities.