JPH0312626A - Image recorder - Google Patents

Abstract

PURPOSE:To adjust the position of a grating in a light beam advancing direction with high accuracy by providing a 1st adjusting means for moving a drum unit in a subscanning conveyance direction so that the unit can be finely adjusted and a 2nd adjusting means for moving the grating in the drum unit in the light beam advancing direction so that it can be finely adjusted. CONSTITUTION:The drum unit 18 is constituted so that it can be moved in the subscanning conveyance direction shown by an arrow (b) by the adjusting means 58. A supporting member 50 slides along the upper side of a guiding rail 53 by rotating an adjusting screw 54 and adjusting the position thereof, and the adjusting means for moving the grating 26 in a direction shown by an arrow (d), that means, the back-and-forth direction of a laser beam advancing direction so that the position of the grating 26 may be adjusted is constituted in the member 50. After adjusting the position of an optical unit 14 and the position of the drum unit in the back-and-forth direction of the subscanning conveyance direction, the position of the grating 26 for synchronizing an image in the laser beam advancing direction is adjusted. Thus, the position of the grating 26 in the back-and-forth direction of the light beam advancing direction is adjusted with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image recording apparatus having a grating for generating an image synchronization signal for highly accurate scanning image recording.

<Prior Art> Various raster scan type image recording devices using light beams such as laser beams have been proposed and put into practical use.

Such an image recording device generally uses a light deflector to deflect a light beam modulated according to the image to be recorded in the main scanning direction, and the recording material is conveyed in a sub-scanning direction in a direction substantially perpendicular to the main scanning direction. is exposed two-dimensionally to record an image.

Here, in order to record a good image with high image quality and an accurate image size even when recording an enlarged or reduced image, the modulated light beam must be directed according to the image to be recorded on the recording material. It is necessary to deflect and irradiate the light beam to an accurate position, and to keep the scanning speed of the light beam constant.

However, it is difficult to keep this strictly constant due to the mechanism of the device, so the usual method is to create a position detection signal for the scanning light according to the optical deflector and synchronize with this signal to record the image. Commonly used.

As a means of generating such a position detection signal, a so-called grid is used, which alternately has parts where the light beam can pass and parts where it cannot pass. A position detection signal (hereinafter referred to as an image synchronization signal) of the image recording light beam is obtained by scanning with a grating light beam deflected by a light deflector and measuring changes in the light intensity of the light beam. , an image recording apparatus that adjusts the main scanning of the recording light beam based on this image synchronization signal receives each f! Proposed.

An example of such an image recording device having a grid for image synchronization is shown in FIG. 5a.

In this image recording device 500, a light beam 502a emitted from a light source 502 is transmitted to a polarizing beam splitter 502.
04, so divide it into two.

One of the split light beams is modulated by an AOM (acousto-optic modulator) 506, and the other light beam is left as is and combined again into a single optical axis by a mirror 508, 510 and a beam splitter 512. .

A light beam 502b, which is a combination of a modulated light beam and an unmodulated light beam, enters a galvanometer mirror 514, is reflected and deflected in the main scanning direction, and then passes through an fθ lens 516 to a predetermined position ( The beam diameter is adjusted so that the image is formed equally on the recording material A).

Light beam 502b adjusted by fθ lens 516
then enters the polarization splitting mirror 518. The light beam 502b is again split into a modulated light beam and an unmodulated light beam by the polarization splitting mirror 518, one of which passes through the polarization splitting mirror 518 and is sent to the exposure drum 520.
The nip rollers 522 and 524 form an image on the recording material A which is sub-scanned and conveyed at a predetermined exposure position in the direction indicated by the arrow, and the recording material A is two-dimensionally scanned and exposed.

On the other hand, the light beam reflected by the polarization separation mirror 518 is
The light enters the case 52B and scans it.

The light beam that has passed through the grating 526 enters the condensing bar 528, is detected as an optical signal by a photodetector (not shown), and is converted into an electrical signal.

Obtains electrical signals for image synchronization.

Another example of an image recording device with such an image synchronization grid is shown in FIG. 5b.

The previous image recording device 500 splits the light beam emitted from one light source 502 to provide a recording light beam and a grating scanning light beam. The image recording device 550 shown in FIG.
54, both of which are reflected and deflected by a galvanometer mirror 514.

In other words, the light beam 55 emitted from the recording light source 552
2a is reflected by the galvanometer mirror 514.
It is deflected and passes through the fθ lens 516, and is imaged onto the recording material A, which is scanned and exposed two-dimensionally.

On the other hand, the light beam 5 emitted from the grating scanning light source 554
54a is similarly reflected and deflected by the galvanometer mirror 514, passes through the fθ lens 516, and is then reflected by the mirror 556 in a substantially perpendicular direction to form the grating 5.
26 and scan it.

Here, in the image recording devices 500 and 550,
The light beams incident on the grating 526 are both deflected in the same way as the light beam incident on the recording material A, and
Since the light intensity changes periodically according to the scanning of the grating, the electrical signal obtained by measuring this change in light intensity is used to detect the exact position of the recording light beam. Image synchronization signal can be obtained,
This synchronization signal allows the scanning of the light beam on the recording material A to be made more precise.

<Problems to be Solved by the Invention> Incidentally, it is extremely difficult to manufacture such an image recording device 100% according to the design in terms of cost, etc., and it is difficult to manufacture such an image recording device 100% according to the design. Manufacturing errors, installation errors, and angle errors may occur.

Additionally, the use of image recording devices, even if originally manufactured and installed correctly, and
It is quite conceivable that the mounting angle and position of the beam light source etc. may be distorted due to movement or external impact.

Therefore, in order to consistently irradiate a light beam onto a recording material and a predetermined position on a grating for image synchronization and to perform good image recording, manufacturing errors and mounting errors in various optical components such as f-theta lenses and galvanometer mirrors must be avoided. Depending on the deviation of the angle, etc.
When attaching the light source, exposure drum, grid, etc., it is necessary to suitably adjust the position, angle, etc.

For example, if the light source is installed at an incorrect angle in the vertical direction, the light beam irradiation position on the recording material or grating will shift in the front-back direction in the sub-scanning conveyance direction. In the case of an apparatus in which each light beam light source is installed at a fixed angle, the exposure drum and grating must be moved eight times in the sub-scanning conveyance direction to adjust the irradiation position of the light beam on the recording material and the grating. Need to adjust.

However, in conventional image recording devices, such adjustments need to be made for each of the mirrors, exposure drums, and gratings, which takes time and effort, and adjustment means are also required for each individual. The problem is that it becomes complicated.

In particular, when high-quality and surface-accurate image recording is required, such as in an image recording device for printing plate making, the position of the exposure drum and grid can be adjusted with extremely high precision even for adjustment amounts of several millimeters. Therefore, the adjustment becomes even more troublesome, and the adjustment means also becomes complicated and expensive.

In addition, f-theta lenses used numerically usually have an error of about 1% or less in focal length. For example, when an f-theta lens with a focal length of 9500 mm is used, the focal length has a maximum error of ±5.0 mm. There is some degree of error. Therefore, in order to record good images, if the optical deflector and fθ lens are fixed, a light source or an exposure drum and a It is necessary to suitably adjust the position of the grid.

However, as mentioned above, in the field of printing and plate making, for example, precision requirements for the size of recorded images are very strict. The accuracy requires adjustment with a high precision of about ±50 μm compared to an adjustment of several mm, making the position adjustment of the grating increasingly complicated.

An object of the present invention is to solve the problems of the prior art as described above, and uses a raster scan method to provide an exposure drum for supporting and transporting recording material at a predetermined recording position, and a grating for image synchronization. In an image recording device having fθ
A simple mechanism makes it easy to adjust the position of the exposure drum and grating for image synchronization due to errors in the focal length of the lens, errors in the position and angle of the installation of the light beam, etc., and deviations. In order to record images with precision and accurate image size, the light source of the light beam and the exposure should be adjusted according to errors in the focal length of the f-theta lens and errors in the position and angle of the light source. It is an object of the present invention to provide an image recording device that can adjust the position of the drum, image synchronization grating, etc., and then adjust the position of the grating in the light beam traveling direction with higher precision.

Means for Solving the Problems> In order to achieve the above object, the present invention includes a light source, an optical deflector that deflects a light beam emitted from the light source in a main scanning direction, and a light deflector that deflects a light beam emitted from the light source in a main scanning direction. An image recording apparatus comprising an exposure drum for supporting a recording material sub-scan conveyed in orthogonal sub-scanning directions at an exposure position, and a grating for image synchronization, the exposure drum and the grating being integrated. a first adjusting means disposed in a drum unit and finely adjustable to move the drum unit in the sub-scanning transport direction; and a second adjusting means disposed in the drum unit to finely adjust the grating in the light beam traveling direction. An image recording apparatus is provided, characterized in that it has an adjusting means.

Further, it is preferable that the first adjusting means is configured to be able to individually adjust the sub-scanning conveyance direction of the drum unit at both ends in the width direction of the exposure drum.

Preferably, the second adjusting means is configured to be able to individually adjust the movement of the grating in the light beam traveling direction at both ends of the grating in the main scanning direction.

Further, the image recording device further includes a collimator lens for shaping the light beam and an fθ lens for focusing the light beam on a recording material, and the light beam source;
It is preferable that the optical deflector, collimator lens, and fθ lens are arranged as an integral unit.

<Action of the invention> The image recording apparatus of the present invention has the above-mentioned predetermined configuration.

Therefore, for example, when installing a light beam source, the position of the exposure drum and grating in the sub-scanning conveyance direction is adjusted to adjust the deviation of the light beam irradiation position on the recording material and image synchronization grating due to angular deviation, etc. The adjustment may be performed by using the first adjustment means to move a drum unit in which an exposure drum and a grating for image synchronization are integrally arranged.
The light beam irradiation position can be adjusted easily and satisfactorily.

Furthermore, this drum unit has a second adjustment means for moving the grating for image synchronization in the light beam traveling direction, so that the optical distance can be adjusted, for example, in order to correct errors in the focal length of the fθ lens, etc. At this time, the optical distance is adjusted by moving the position of the light beam light source, etc., and the position of the drum unit is further adjusted by the first adjusting means, and then the position of the grating is further precisely adjusted by the second adjusting means. can do. Therefore, the present invention can be suitably applied even to image recording apparatuses that require high accuracy in recorded image size, such as image recording apparatuses for printing plate making.

<Embodiments> Hereinafter, an image recording apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 shows a schematic diagram of an embodiment of an image recording apparatus of the present invention.

The image recording apparatus 1o shown in FIG. 1 basically includes an optical surface plate 12 and an optical unit 14 arranged on the optical surface plate 12.
and a drum unit 18 supported by the side plate 16 of the optical surface plate 12, and a laser beam 20 emitted from the exposure laser light source 20 of the optical unit 14.
A is reflected and deflected by a galvanometer mirror 22 as a light deflector in the main scanning direction indicated by the arrow a, and is supported by the exposure drum 24 and conveyed in the sub-scanning direction to the recording position in the direction indicated by the arrow A. In this method, an image is recorded by two-dimensionally exposing a recording material that is not exposed to light.

Further, in the image recording apparatus 10 of the present invention, a grating 26 for image synchronization is arranged on the drum unit 18 having the exposure drum 24, and furthermore, this drum unit 18 is configured to be movable in the fore-aft direction in the sub-scanning direction. Ru.

The optical unit 14 includes an exposure laser light source 20, a grating laser light source 28, a collimator lens 30, a galvanometer mirror 22, and an fθ lens 32, which are arranged inside the housing 34 and on the side thereof. , is configured as a unit.

The exposure laser light source 20 is a laser light source that irradiates a laser beam 20a for exposing a recording material to record an image, and the grating laser light source 28 emits a laser beam 28a that scans the grating 26. The laser beams 20a and 28a are fixed to the side surface of the housing 34 and emit laser beams 20a and 28a to the galvanometer mirror 22 arranged inside the housing 34, respectively.

In addition, as the laser light source in the present invention, various laser light sources commonly used in image recording apparatuses capable of raster scanning, such as various semiconductor lasers and gas lasers, can be used.

In the illustrated apparatus, the exposure laser light source 20 emits a laser beam 20a parallel to the optical surface plate 12, and the grating laser light source 28 emits a laser beam 20a at an angle of about 6° with respect to the laser beam 20a. The laser beam 20a is arranged so as to emit a laser beam 28a downward while holding the laser beam 20a, and the laser beam 20a irradiates the recording material supported and conveyed by the exposure drum 24.
1. The beam enters the grating 26 disposed below and in front of the laser beam (hereinafter, the front is defined as the upstream side in the direction of laser beam movement). is configured to scan the

Laser beams emitted from each laser light source pass through a collimator lens 30 and are shaped. here,
In the illustrated apparatus, a laser beam 20a for exposure is used.
passes through the center of the collimator lens 30.

In the illustrated apparatus, both laser beams are shaped by one collimator lens 30, but it goes without saying that one collimator lens may be provided for each laser beam.

Both laser beams that have been shaped after passing through the collimator lens 30 are then incident on a galvanometer mirror 22 serving as an optical deflector, are reflected, and are deflected in the main scanning direction shown by arrow a.

Note that the optical deflector is not limited to the galvanometer mirror 22, and various types such as a polygon mirror can be used.

The laser beams 20a and 28a reflected and deflected by the galvanometer mirror 22 are then reflected and deflected by fθ, which is arranged on the side surface of the housing 34 adjacent to the side surface on which the laser light source is arranged.
After passing through the lens 32, the laser beam 20a is adjusted to form an image with a predetermined beam diameter at the recording position, and the laser beam 28a is adjusted to form an image on the grating 26.
Each proceeds to the drum unit 18. In the illustrated apparatus, the fθ lens 32 is arranged such that at least the exposure laser beam 20a passes through the center line of the fθ lens 32 in the main scanning direction.

The optical unit 14 is basically configured as described above, but in the illustrated image recording apparatus 10, the optical unit 14 is configured to control the progress of the laser beam after being deflected by the gal/<nometer mirror 22. The attachment is configured so that its position can be adjusted by moving in the direction shown by arrow C, which is the front-rear direction, and can be fixed after adjustment.

fθ lenses used in various image recording devices usually have a focal length error of about 1% or less. That is, for example, in an fθ lens with a focal pressure of 1iI 500 mm, the focal length may be deviated by a maximum of about ±5.0 mm.

Therefore, in order to reliably image the laser beam with a predetermined beam diameter on the recording material, this error (true focal pressure!
It is necessary to adjust the optical distance according to the drum unit 18.
is fixed in the direction of arrow C, so this adjustment is performed by moving the optical unit 14 in the direction of arrow C.

With such a configuration, it is possible to correct the optical distance caused by an error in the focal length of the fθ lens 32 by moving one optical unit 14, allowing easy and accurate adjustment. I can do it.

Exposure drum 2 of optical unit 14 and drum unit 18
The distance to the exposure position No. 4 is determined by the focal length of the fθ lens 32, so after measuring the focus of the fθ lens 32, the distance is measured with a micrometer or the like, and the distance is determined according to the focal length of the fθ lens 32. The optical unit 14 may be securely fixed to the optical surface plate 12 at the fixed position.

The optical unit 14 may be fixed to the optical surface plate 12 by any known method such as bolts, nuts, taper pins, etc. Furthermore, methods for making the optical unit 14 movable in the direction of arrow C on the optical surface plate 12 include a method in which the hole for fixing the optical unit 14 formed in the optical surface plate 12 is made into a long hole, a method in which the hole for fixing the optical unit 14 formed in the optical surface plate 12 is made into a long hole, and a method in which the optical unit 14 is made movable in the direction of the arrow C on the optical surface plate 12 is made. by means of recesses or protrusions engaged therewith;
There are no particular limitations on the method using a drive shaft, etc.

In the image recording apparatus 10 of the present invention, the drum unit 1
Reference numeral 8 denotes an integral unit of an exposure drum 24 for holding and transporting the recording material at the recording position, and a grid 26 for image synchronization. It has nip rollers 36 and 38 that nip and convey the recording material together with the drum 24, a grating 26, a condensing par 40 that condenses the laser beam 28a that has passed through the grating 26, and a photodetector 41.

In the image recording apparatus 10 of the present invention, this drum unit 18 also has an adjusting means 58 (see FIGS. 3 and 4), which will be described later.
2), it is configured to be movable in the sub-scanning conveyance direction indicated by the arrow, and is supported by the support plate 16 of the optical surface plate 12.

FIG. 2 shows a schematic cross-sectional view of the drum unit 18.

In the image recording device 10, the recording material A is placed on the exposure drum 2.
4 and nip rollers 36 and 38, the laser beam 20a is sub-scanned and conveyed in the direction shown by the arrow, and the recording position 24 is
A is exposed and an image is recorded.

The upper surface of the casing 35 has an opening 42 for carrying in the recording material A, the lower surface has an opening 44 for discharging the recording material A, and an optical unit 14 of the casing 35.
An opening 46 through which the laser beam 20a passes and an opening 48 through which the laser beam 28a passes are formed on the opposing surface.

The exposure drum 24 and nip rollers 36 and 38 are pivotally supported by a support member (not shown) or side walls at both ends in the main scanning direction of the housing 35, and a rotation drive source (not shown) for the exposure drum 24 is connected to the exposure drum 24. be done.

A grating 26 for image synchronization is supported and fixed to the lower front force of the exposure drum 24 by a supporting member 50, and a laser beam 28a that has passed through the grating 26 is focused behind the grating 26 and is incident on a photodetector 41. A light condensing bar 40 is arranged.

Also, the laser beam 28a incident on the photodetector 41
is photoelectrically converted into electrical and mechanical signals for image synchronization.

The laser beam 28a incident on the grating 26 is reflected and deflected by the galvanometer mirror 22 in exactly the same way as the laser beam 20a exposing the recording material A.

Therefore, a synchronization signal for detecting the accurate position of the laser beam 20a can be obtained from an electrical signal obtained from periodic changes in light intensity in accordance with the scanning of the grating 26 by the laser beam 28a, and from this synchronization signal. Main scanning of the laser beam 20a on the recording material A can be made more precise.

Note that in the illustrated example image recording device 10, the grid 26
is arranged in front of the exposure drum 4.

Most preferably, the optical path lengths of the exposure laser beam 20a and the grating scanning laser beam 28a are equal.
However, since the grating 26 is only a means for obtaining an image synchronization signal, it is placed at a predetermined position that is preset according to the focal length of the fθ lens 32 (FIG. 1) to obtain an accurate image synchronization signal. The optical path lengths of both laser beams do not need to be perfectly matched as long as the structure is such that the optical path lengths of both laser beams can be completely matched.

Here, in the illustrated apparatus, due to astigmatism, the beam spot of the laser beam becomes long in the vertical direction (in the direction indicated by the arrow) when the image is formed at a distance shorter than the focal length. Therefore, even if the optical path length is somewhat shorter than the focal length, if the grating 26 is placed at the predetermined position mentioned above, the grating 26
According to studies by the present inventors, it has been found that if the difference in optical path length is set to 15% or less, there is no particular adverse effect.

There are no particular limitations on the grid 26 that can be applied to the present invention, and conventional image synchronization methods may be used, such as one in which slits are formed by vapor-depositing chromium or the like on glass, or one in which slits are formed by printing black ink on a transparent film. Any grid is applicable. Further, the interval between the grids may be appropriately determined depending on the image to be recorded, and may be approximately 10 pixels of the recorded image.

As mentioned above, the grating 26 and the focusing bar 40 are attached to the support member 5.
Supported and fixed at 0. The support member 50 is supported by a guide rail 53 near both ends in the main scanning direction, and has adjustment screws 54 screwed into the member 52.

The member 52 and the guide rail 53 are fixed to, for example, the inner surface of the housing 35, and an adjustment screw 54 screwed into the member 52 can be rotated to move in the direction of arrow d.

Further, the support member 50 supported by the adjustment screw 54 is urged toward the optical unit 14 by a spring 56.

Therefore, by rotating the adjustment screw 54 and adjusting its position, the support member 50 is configured to slide along the upper surface of the guide rail 53 and to be movable in the direction of the arrow d. An adjusting means is configured that adjusts its position by moving in the direction of arrow d, that is, in the front and back direction of the laser beam traveling direction.

As mentioned above, the focal length of a commonly used f-theta lens usually has an error of about 1% or less, and in the image recording device 1° shown in FIG. 1, the optical unit is moved in the direction of arrow C. Accordingly, the optical distance is adjusted.

However, for example, in image recording devices for printing plate making, the size of the image to be formed requires extremely high precision (error of 10
In fields where a laser beam of about 0 μm) is required, the position of the grating 26 with respect to the laser beam traveling direction shown by arrow d must be adjusted with very high precision in order to record an image of an accurate size. In other words, if the position of the grating 26 is even slightly deviated in the direction of arrow d from a predetermined position set in advance according to the focal length of the fθ lens 32 (FIG. 1), the main beam of the exposure laser beam 20a During scanning, the irradiation position cannot be detected accurately, and it becomes impossible to record an image of an accurate size.

Therefore, as in the image recording apparatus 1o of the present invention, in addition to adjusting the optical distance by the optical unit 14, by having a position adjusting means for the grating 26, it is possible to adjust the position of the optical unit 14 and the sub-scanning conveyance direction of the drum unit, which will be described later. After adjusting the position in the front-rear direction, the position of the image synchronization grating 26 in the laser beam traveling direction can be easily adjusted.
Moreover, it can be performed with high precision, and can be suitably applied to fields that require image recording of accurate size, such as image recording devices for printing plate making.

According to the example explained above, the position adjustment means for the grating 26 is
Although the laser beam traveling direction of the grating 26 can be adjusted near both ends of the grating 26, the present invention is not limited to this.
6 (support member 50) may be configured to be adjustable.

However, by enabling position adjustment near both ends of the grating 26, even when the emission angle of the laser beam 28a from the grating laser light source 28 is deviated in the plane direction, the laser beam 28a is always kept at a predetermined position. It becomes possible to make the light incident on the grating 26 at an angle, and it becomes possible to always obtain an accurate image synchronization signal.

In the image recording apparatus of the present invention, the means for adjusting the position of the grating 26 is not limited to the method described above, and any known means for adjusting the position using a link mechanism, a rack and pinion, a drive shaft, etc. Applicable.

Such a drum unit 18 is
Adjustment means disposed on both sides of the optical surface plate 12 in the main scanning direction allow the recording material A to be moved in the longitudinal direction (hereinafter referred to as the vertical direction) in the sub-scanning conveyance direction indicated by the arrow. It is supported by a support plate 16.

FIG. 3a shows a front view of this adjusting means 58, and FIG. 4 shows a plan view thereof. Note that although the illustrated example shows only the adjusting means 58 on one side of the drum unit 18, the adjusting means on the other side also has a similar configuration, so a description thereof will be omitted.

The adjustment means 58 basically includes a substrate 60 fixed to the support plate 16, a guide member 62 fixed to the substrate 60, and a guide member 62 that is inserted into a guide groove 62a of the guide member 62 and supported so as to be movable in the direction of arrow e. a member 66 fixed to the side surface of the housing 35 of the drum unit 18 that engages with the drive member 64, and an adjustment screw 68 for moving the drive member 64 in the direction of arrow e. It is something.

In the illustrated example, the substrate 60 is the support plate 16 of the optical surface plate 12.
The adjusting means 58 is fixed at right angles to the adjusting means 58, and supports the entire adjusting means 58.

An adjustment screw 68 is rotatably supported on this board 60.
Further, the guide member 62 in which the guide groove 62a into which the drive member 64 is inserted is fixed.

A drive member 64 is inserted into the guide groove 62a of the guide member 62, and is placed and supported so as to be movable in the direction of arrow e.

This drive member 64 has a screw hole 7 into which an adjustment screw 68 is screwed.
0 is formed, and is configured to be movable in the direction of arrow e by rotating the adjustment screw 68. Further, an inclined portion 72 is formed at the upper portion of the driving member 64 .

The member 66 is a member having a sliding surface 74 formed therebelow that engages with the inclined portion 72 of the drive member 64, and is fixed to the side surface of the housing 35. Therefore, the drum unit 18 is supported by this member 66 at a position m on the inclined portion 72 of the drive member 64.

In addition, by adopting a configuration in which the sliding surface 74 is supported by the inclined portion 72, the drum unit 18 can be kept in a suitable state pressed against the substrate 60 at all times, and the position of the exposure drum 24 with respect to the traveling direction of the laser beam 20a. can always be kept constant.

Here, since the driving member 64 is moved in the direction of the arrow e by rotating the adjustment screw 68 as described above, the member 66 placed on the driving member 64 is As the drum unit 64 moves, it moves up and down along the inclined portion 64 while bringing its sliding surface 74 into contact with each other, thereby causing the drum unit 18 to move up and down.

That is, in the illustrated example, by rotating the adjustment screw 68, the driving member 64 is moved in the direction of the arrow e, so that the drum unit 18 can be moved up and down. For example, as shown in FIG. By moving the member 64 to the right in the figure, the drum unit 18 is moved downward to B.
can move.

In the image recording apparatus 10 of the present invention, by having such a position adjustment means 58 for the drum unit 18, for example, when the mounting angle of the optical unit 14 is deviated and the irradiation position of the laser beam is shifted in the vertical direction, However, by adjusting the position of the drum unit 18, it becomes possible to reliably make the laser beam 20a enter the recording position 24a (FIG. 2), and it becomes possible to always perform good image recording.

Moreover, unlike conventional devices, the exposure drum 24 and the grating 2
Since there is no need to adjust the vertical position of 6 individually, adjustment is very easy, and it is suitable for fields that require high quality and high precision image recording, such as image recording devices used in printing plate making. Even when high-precision adjustment is required, there is no need for complicated adjustment means.

Note that in the image recording apparatus 10 of the present invention, a fixing means for the drum unit 18 is provided, and such an adjusting means 5
It is preferable to have a fixing means for reliably fixing the drum unit 18 after the position of the drum unit 18 is adjusted by the drum unit 8.

There is no particular limitation on such fixing means, and any known fixing means such as screws, bolts, nuts, etc. can be applied.

According to the example described above, the adjustment means 58 are arranged at both ends of the drum unit 18 to adjust the position of the drum unit 18, but the present invention is not limited to this, and the adjustment means 58 are arranged at both ends of the drum unit 18 to adjust the position of the drum unit 18. The position of the drum unit 18 may be adjusted by the means 58.

However, due to incorrect installation of the optical unit 14, inclination of the galvanometer mirror 22, etc., the laser beam 20a may not be main-scanned completely parallel to the optical surface plate 12. Therefore, by configuring the adjusting means 58 to be provided at both ends of the drum unit 18 to adjust the position of the drum unit as in the illustrated apparatus, the adjustment means 58 can be adjusted according to the inclination in the plane direction of the main scanning of the laser beam 20a. Drum unit! 8, that is, the drum unit 18 can be fixed obliquely, and the laser beam 20a can always be irradiated onto a predetermined recording position, thereby achieving more preferable results.

As above, the image recording device according to the present invention has been described in detail based on the preferred embodiments shown in the attached drawings, but the present invention is not limited thereto, and within the scope of the gist of the present invention. Of course, various changes and improvements may be made.

<Effect of the invention> The image recording apparatus of the present invention has the above-mentioned predetermined configuration.

Therefore, the adjustment of the longitudinal deviation of the light beam irradiation position on the recording material and the image synchronization grating in the recording material sub-scanning conveyance direction, which was conventionally performed individually for the exposure drum and the image synchronization grating, is now possible. This can be done by moving the drum unit in which the drum and the grid for image synchronization are integrally arranged using the first adjustment means, and there is no need to use a large number of complicated adjustment means even when precise adjustment is required. Therefore, the light beam irradiation position can be easily and favorably adjusted.

In addition, since the drum unit has a second adjustment means for moving the image synchronization grating in the light beam traveling direction, f
After adjusting the optical distance by moving the position of the light source etc. according to the focal length of the θ lens, and adjusting the position of the drum unit in the front-rear direction in the sub-scanning conveyance direction by the first adjusting means,
The position of the grating in the longitudinal direction of the light beam traveling direction can be adjusted more precisely. Therefore, it is possible to obtain an image synchronization signal that can always accurately determine the scanning position etc. during main scanning with a light beam. It is also possible to suitably apply the present invention to image recording apparatuses.

Preferably, the first adjustment means is configured to be able to be adjusted individually at both ends of the exposure drum in the width direction, so that the drum unit can be adjusted in accordance with the inclination in the plane direction of the main scanning of the exposure laser beam. That is, it becomes possible to fix the drum unit obliquely, and it becomes possible to always irradiate the exposure laser beam onto a predetermined recording position.

Preferably, the second adjustment means is configured to be able to be adjusted individually at both ends of the grating in the main scanning direction, so that when the emission angle of the laser beam from the grating laser light source is deviated in the plane direction, Even in this case, it is possible to always make the grating laser beam incident on the grating at a predetermined angle.

Further, preferably, by integrating a laser light source, a light deflector, an fθ lens, etc. into an optical unit, fθ
Correction of optical distance caused by lens focal length error,
This can be done by adjusting one optical unit, and the optical distance can be adjusted easily and accurately.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of an example of an image recording apparatus according to the present invention. 2 is a schematic sectional view of the drum unit of the image recording apparatus shown in FIG. 1. FIG. 3a and 3b are schematic side views of the first adjustment means applied to the image recording apparatus shown in FIG. 1. FIG. FIG. 4 is a schematic front view of the first adjusting means shown in FIGS. 3a and 3b. Figures 5a and 5b are schematic diagrams of a conventional image recording device. Explanation of symbols 10... Image recording device, 12... Optical surface plate,
14... Optical unit, 16... Support plate, 1
8... Drum, unit, 20... Laser light source for exposure, 20a... Laser beam for exposure, 22... Galvanometer mirror 24... Exposure drum, 26... Grid, 28
... Laser light source for grating, 28a... Laser beam for grating, 30... Collimator lens, 32... fθ lens, 34.35... Housing, 36.38... Nip roller, 40. ...Condensing bar 42.44, 46.48...Aperture, 50...Support member, 52.66...Member, 54.68...Adjustment screw, 58...Adjustment means, 62. ...Guide member, 70...Screw hole, 74...Sliding motion, 56...Spring, 60...Base, 64...Driving member, 72...Slanted part,

Claims (1)

[Claims] (1) A light source, an optical deflector that deflects the light beam emitted from the light source in the main scanning direction, and a recording material that is sub-scanned and conveyed in the sub-scanning direction substantially perpendicular to the main-scanning direction, which is supported at the exposure position. An image recording device comprising an exposure drum for image synchronization and a grating for image synchronization, wherein the exposure drum and the grating are integrally arranged in a drum unit, and the drum unit can be finely adjusted in the sub-scanning conveyance direction. An image recording apparatus comprising: a first adjustment means for moving the grating in the direction of travel of the light beam within the drum unit; and a second adjustment means for finely adjusting the movement of the grating in the direction in which the light beam travels within the drum unit.