JP2005274898A - Exposure equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute an exposure apparatus capable of forming a high quality image even when the conveyance speed of photographic paper fluctuates.
SOLUTION: Two laser light sources 13R-T, 13R-D, two modulators 14R-T, 14R-D are provided to send out two laser beams LB, LB, and the two laser beams LB, LB are transmitted. Each of the laser beams LB and LB is guided in the approaching direction by being reflected by the inclined mirror surfaces 16MT and 16MD of the polygon mirror 16, and the laser beams LB and LB are guided in the sub-scanning direction on the photosensitive surface of the photographic paper P. Exposure is performed in such a form that irradiation is performed in the adjacent positional relationship.
[Selection] Figure 3

Description

  The present invention relates to an exposure apparatus that exposes a photosensitive material conveyed in a sub-conveying direction by reflecting a laser beam from a light emitting unit by a rotating polygon mirror and scanning in the main scanning direction.

  As an exposure apparatus configured as described above, there is one disclosed in Patent Document 1. In this Patent Document 1, a modulation circuit that includes three types of light source units that use a semiconductor laser as a light source so as to develop a photosensitive material in three primary colors of C, M, and Y, and that determines the amount of light from each light source unit; A rotary polygon mirror that realizes scanning by reflecting light rays from the light source unit and a sub-scanning conveying unit that conveys the photosensitive material in the sub-scanning direction, and controls the light emission time of the light source unit based on the recorded image. Thus, an image is formed on the photosensitive material.

JP-A-6-106774 (paragraph numbers [0018] to [0042], FIG. 1)

  As an example of a photosensitive material that exposes photographic paper, this type of exposure apparatus transports photographic paper in the sub-scanning direction at a set speed, and in the main scanning direction at a timing synchronized with the transport speed. Since the line-shaped exposure is performed, when the conveyance speed for feeding the photosensitive material in the sub-scanning direction fluctuates, even if the disturbance in the conveyance speed does not affect the image quality, it is finished. In the photograph, gaps were formed between the exposed areas in a line shape, which sometimes deteriorated the quality. More specifically, in an exposure apparatus that exposes photographic paper that has been cut in advance to a print size, a conveyance roller that can be switched between a crimping state and an open state is disposed in the photographic paper conveyance system. On the other hand, when the photographic paper comes into contact with the photographic paper, the photographic paper may vibrate or the conveyance speed may fluctuate slightly. For this reason, the speed of the photographic paper in the sub-scanning direction fluctuates, and the image quality is sometimes lowered.

  An example of the reason why the linear gap is formed between the exposure regions in this way is that the beam diameter of the laser beam is small. In order to eliminate this inconvenience, it is conceivable to increase the beam diameter by slightly diffusing the laser beam. However, when the beam diameter is increased in this way, the resolution in each of the main scanning direction and the sub-scanning direction is reduced. It was difficult to adopt because it was lowered.

  An object of the present invention is to rationally configure an exposure apparatus that can form a high-quality image even when the conveyance speed of the photosensitive material varies.

A feature of the present invention is that in an exposure apparatus that exposes a photosensitive material conveyed in the sub-conveying direction by reflecting the laser beam from the light emitting means by a rotating polygon mirror and scanning in the main scanning direction.
The light emitting means includes a plurality of laser light sources that emit laser beams, and includes a modulator that independently controls the light amount of the laser beams from the plurality of laser light sources, and the light amount is controlled by each modulator. An optical system for irradiating the photosensitive material with a positional relationship adjacent to the photosensitive material in the sub-scanning direction, and a plurality of modulators for controlling the light amounts of the plurality of laser beams irradiated with the adjacent positional relationship. There is a light amount control means for controlling with the same image data.

  With this configuration, exposure can be performed by controlling the light amounts of a plurality of laser beams that are adjacent to each other in the sub-scanning direction with the same image data, so that the resolution in the main scanning direction is not reduced in the sub-scanning direction of the laser beam. The exposure width of the laser beam can be enlarged, and the overlapping amount of laser beams in the sub-scanning direction can also be increased. As a result, even when the conveyance speed of the photosensitive material fluctuates, a line-shaped gap is not formed between the exposed areas, and a good quality image is formed.

  The present invention includes a pair of the laser light sources corresponding to three light sources of three primary colors of R (red), G (green), and B (blue), and the optical system is parallel to the pair of laser light sources. The polygon mirror may be provided with a mirror surface set in an attitude so as to guide the laser beam sent out in step 1 to a positional relationship adjacent in the sub-scanning direction on the photosensitive surface of the photosensitive material.

  With this configuration, a pair of laser beams corresponding to the three primary colors R (red), G (green), and B (blue) are adjacent to each other in the sub-scanning direction on the photosensitive surface of the photosensitive material by reflection of the mirror surface of the polygon mirror. It was possible to perform exposure by guiding it.

The present invention relates to an exposure apparatus that exposes a photosensitive material conveyed in the sub-conveying direction by reflecting the laser beam from the light emitting means with a rotating polygon mirror and scanning in the main scanning direction.
The light emitting means is composed of a laser light source that emits a laser beam, and includes a modulator that controls the amount of the laser beam from the laser light source, and generates a plurality of laser beams from the laser beam from the modulator; and , And a beam converter for sending each laser beam in an adjacent parallel posture, and an optical system for setting the adjacent direction of the pair of laser beams sent from the beam converter in the sub-scanning direction.

  With this configuration, a plurality of laser beams can be generated by the beam converter without using a plurality of laser light sources that emit laser beams and modulators that control the amount of light of the laser beams. Thus, it is possible to carry out exposure with respect to the photosensitive material in an adjacent positional relationship. As a result, a conventional polygon mirror and an optical system that guides the light beam reflected by the polygon mirror to the photosensitive material can be used as they are. Thus, a good quality image was formed without forming a line-shaped gap.

  The present invention includes, as the beam converter, a beam splitter for branching a laser beam sent out along a main optical path, and a pair of laser beams adjacent to the laser beam branched by the beam splitter in a posture parallel to the main optical path. A mirror or a prism may be provided.

  With this configuration, the main optical path is branched from the main optical path by a beam splitter that is sent, returned to the main optical path by a mirror or a prism, and converted into a pair of adjacent laser beams in a posture parallel to the laser beam sent to the main optical path. Therefore, exposure can be performed without greatly modifying the conventional exposure apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment] As shown in FIGS. 1 and 2, a pair of driving rollers 3 and 3 to which a driving force from a conveying motor 1 is transmitted via a belt transmission mechanism 2 are arranged correspondingly. And a driven unit for transporting the photographic paper P as a photosensitive material from below to above (this transport direction is the sub-scanning direction), and the printing unit transported in the sub-scanning direction by this transport unit. An exposure unit that exposes a linear region by scanning a pair of laser beams LB, LB adjacent to the paper P in the sub-scanning direction along a main scanning direction (horizontal direction) orthogonal to the sub-scanning direction. An exposure apparatus is configured.

  The transport unit is set in a transport direction so as to send the photographic paper P, which has been cut to a print size in advance, from below to above, and exposure of the laser beams LB and LB is performed at an intermediate position between the drive rollers 3 and 3 positioned above and below. Position X is set. Although not shown in the drawing, the transport unit includes a switching mechanism for independently switching the pair of driven rollers 4 and 4 between a crimping position and an open position, and this switching mechanism places the lower driven roller 4 in the open position. The printing paper P is set and accepted, and after this acceptance, the printing paper P is started to be conveyed by the driving force of the lower driving roller 3 by switching to the crimping state. Thereafter, when the photographic paper P for which exposure has been started is transported, the upper driven roller 4 is set to the open position to receive the photographic paper P, and after this reception, the state is switched to the pressure-bonded state. Thereafter, by switching the lower driven roller 4 to the open position, an operation sequence is set so that the exposure is continued while the photographic paper P is conveyed by the driving force of only the upper driving roller 3.

  The exposure unit emits the laser beams LB and LB that are set to equal light amounts so that a part of each of the laser beams LB and LB overlaps when the laser beams LB and LB are adjacent in the sub-scanning direction at the exposure position X. As shown in FIG. 5, the positional relationship of the exposure is set so that the area EL to be exposed next overlaps the area EP that has already been exposed on the photographic paper P slightly in the sub-scanning direction. .

  The exposure unit includes a light emitting means for emitting a laser beam inside a housing 12 of a light metal alloy such as an aluminum alloy having a sealed structure provided with a dustproof glass 11 at an opening for sending out the laser beams LB, and a light quantity of the laser beam. And an optical system that guides the laser beam LB to the exposure position.

  The light emitting means includes a pair of laser light sources 13R-T arranged at upper and lower positions so as to emit an R (red) laser beam LB so as to constitute three primary colors of R (red), G (green), and B (blue). 13R-D, a pair of laser light sources 13G-T and 13G-D arranged at the upper and lower positions so as to emit the G (green) laser beam LB, and an upper and lower position so as to emit the B (blue) laser beam LB A pair of laser light sources 13B-T and 13B-D (referred to as laser light sources 13). The modulation means includes red modulators 14R-T and 14R-D and green modulators 14G-T and 14G-, which are acousto-optic conversion elements so as to control the light quantity of the laser beam LB from the laser light source 13. D and blue modulators 14B-T and 14B-D are provided (referred to as modulators 14).

  The optical system includes a pair of upper and lower red beam mirrors 15R-T and 15R-D arranged at upper and lower positions so as to reflect the laser beam LB, and a pair of upper and lower green beam mirrors 15G-T and 15G-D. And a pair of upper and lower blue beam mirrors 15B-T and 15B-D, and a polygon mirror 16 made of a light alloy such as aluminum to which the laser beam LB from these beam mirrors is guided, and reflected by the polygon mirror 17. A laser beam reflected by a timing mirror 19 when the laser beam LB from the pair of upper and lower fθ lens groups 18T and 18D for guiding the laser beam LB to the photographic paper P at the exposure position X and the polygon mirror 16 reaches the scanning end. And a synchronization sensor 20 for detecting from the beam LB. The polygon mirror 16 is supported so as to be rotatable around a longitudinally oriented axis Y, and is rotated by a driving force from a mirror motor 17 that rotates in synchronization with a driving signal.

  The R (red) laser light sources 13R-T and 13R-D are configured in a semiconductor laser type, and the G (green) and B (blue) laser light sources 13G-T, 13G-D, 13B-T, and 13B. -D is configured as a solid-state laser.

  The polygon mirror 16 has a structure that rotates at a rotational speed corresponding to the frequency of the drive signal by supplying a drive signal to the mirror motor 17, and as shown in FIGS. This polygon mirror 16 is formed into a plurality of pairs of mirror surfaces 16M-T and 16M-D in a plurality of up-and-down positional relationships by finishing the outer peripheral surface, which is a regular polygon when viewed in the direction along the axis Y, into a flat mirror surface. Has been. The fθ lens groups 18T and 18D are composed of a plurality of cylindrical lenses, and a laser beam LB that is scanned equiangularly (scanned at a constant angular velocity) in the main scanning direction by rotation of the polygon mirror 16 on the photosensitive surface of the photographic paper P. It functions to convert to a laser beam LB for constant speed scanning (scanning at a constant linear velocity).

  Further, the mirror surfaces 16M-T and 16M-D are formed so as to be inclined with respect to the axis Y so that the laser beams LB and LB are adjacent in the sub-scanning direction at the exposure position X, and the pair of fθ The lens groups 18T and 18D are arranged at positions where the laser beams LB and LB reflected by the mirror surfaces 16M-T and 16M-D of the polygon mirror 16 are linearly guided.

  Taking a system for sending out red laser beams LB and LB as an example, as shown in FIG. 3, this optical system emits laser beams LB and LB from a pair of upper and lower laser light sources 13R-T and 13R-D. The beams are sent out in a parallel posture, reflected from the modulators 14R-T and 14R-D by the beam mirrors 15R-T and 15R-D, and guided to the mirror surfaces 16M-T and 16M-D of the polygon mirror 16 while maintaining the parallel posture. The respective laser beams LB and LB are reflected by the mirror surfaces 16M-T and 16M-D in a direction approaching each other, and the reflected laser beams LB and LB are exposed from the fθ lens groups 18T and 18D as described above. The exposure is performed by irradiating the photosensitive surface of the photographic paper P at position X so as to be adjacent to each other in the sub-scanning direction (see FIG. 5).

  Among the red modulators 14R-T and 14R-D, the green modulators 14G-T and 14G-D, and the blue modulators 14B-T and 14B-D, the light amount of the laser beam LB having the same hue. Are controlled based on the same image data.

  That is, as shown in FIG. 4, image data having a bitmap structure having 8-bit density data is stored in three storage areas corresponding to the three primary colors R (red), G (green), and B (blue). An image data storage unit 22 composed of a semiconductor memory (RAM) is provided, and a control device 23 to which image data from the image data storage unit 22 is input is provided. From the control device 23, the laser light source 13 and the modulator 14 are provided. And a signal system for outputting a control signal to the mirror motor 17 and a signal system for inputting a signal from the synchronous sensor 20 are formed. The control device 23 includes light amount control means 23A composed of software, hardware, or a combination thereof in order to control the modulator 14 based on the image data stored in the image data storage unit 22. ing.

  With this configuration, when the image data stored in the image data storage unit 22 is exposed on the photographic paper P, the polygon mirror 16 is rotated at the set line speed by the driving force of the mirror motor 17, and this rotation is performed. The conveyance motor 1 is driven at a speed synchronized with the rotation of the printing paper P to start conveyance, and power is supplied to the three types of laser light sources 13 to emit light. When the photographic paper P reaches a position where exposure can be performed by conveyance, the density data of the line-shaped region corresponding to the main scanning direction is obtained from the image data stored in the three storage regions of the image data storage unit 22. The light amounts of the laser beams LB and LB are controlled by sequentially reading them and transferring them to the corresponding modulators 14 at a predetermined timing when the synchronous sensor 20 detects the laser beams. In particular, when the light amounts of the laser beams LB and LB are controlled in this way, the pair of modulators 14R-T and 14R-D are controlled based on the density data of R (red), and the G (green) The pair of modulators 14G-T and 14G-D are controlled based on the density data, and the pair of modulators 14B-T and 14B-D are controlled based on the density data of B (blue). Thus, the photographic printing paper P can be exposed in a line along the main scanning direction in such a manner that the light amounts of the laser beams LB and LB are equally controlled.

  That is, the light amounts of the laser beams LB and LB emitted from the pair of laser light sources 13 are controlled by the corresponding pair of modulators 14 based on the same image data, and the respective laser beams LB and LB are controlled in the sub scanning direction by the optical system. Even when exposure without reducing the resolution in the main scanning direction is performed by guiding to the photosensitive surface of the photographic paper P in the adjacent positional relationship, and the conveyance speed of the photographic paper P is fluctuated, the exposure area is also in between. It is possible to form a good quality image without forming a line-shaped gap.

  [Second Embodiment] (In this second embodiment, components having the same functions as those in the first embodiment are given the same numbers and symbols as those in the first embodiment.)

  In the second embodiment, the first embodiment is that exposure is performed by scanning the two laser beams LB and LB in the main scanning direction while transporting the photographic paper P as a photosensitive material by the transport unit. The difference is that the two laser beams LB and LB in parallel posture are generated from the laser beam LB from the single laser light source 13 and the exposure is performed with the laser beams LB and LB. Yes.

  That is, as shown in FIGS. 6 and 7, the exposure unit has a laser inside a light metal alloy housing 12 such as an aluminum alloy having a sealed structure having a dust-proof glass 11 in an opening for sending out laser beams LB and LB. A light emitting means for emitting a light beam, a modulating means for controlling the light quantity of the laser beam, and an optical system for guiding the laser beam LB to the exposure position are provided.

  The light emitting means includes a laser light source 13R that emits an R (red) laser beam LB and a G (green) laser beam LB so as to constitute three primary colors of R (red), G (green), and B (blue). And a laser light source 13B that emits a B (blue) laser beam LB (these are referred to as laser light source 13). The modulation means includes a red modulator 14R, a green modulator 14G, and a blue modulator 14B, which are acousto-optic conversion elements so as to control the amount of laser beams LB from the three laser light sources 13. (These are referred to as modulators 14).

  The optical system generates two laser beams LB and LB from the laser beam LB from the modulator 14, and sends out the laser beams LB and LB in an adjacent parallel posture. A beam mirror 15R, a green beam mirror 15G, and a blue beam mirror 15B are provided, and further reflected by a polygon mirror 16 made of a light alloy such as aluminum to which the laser beam LB from the beam mirror is guided, and the polygon mirror 17. The fθ lens group 18 that guides the laser beam LB to the photographic paper P at the exposure position X, and the synchronization in which the timing at which the laser beam LB from the polygon mirror 16 reaches the scanning end is detected from the laser beam LB reflected by the timing mirror 19. And a sensor 20. The polygon mirror 16 is supported so as to be rotatable around a longitudinally oriented axis Y, and is rotated by a driving force from a mirror motor 17 that rotates in synchronization with a driving signal.

  The beam converter A is a total reflection mirror including one beam splitter 31 that branches one laser beam LB sent along the main optical path LM and two total reflection mirrors 32 that reflect the branched laser beam LB. The half mirror 33 is configured to send the laser beam LB returned in the direction of the main optical path ML in 32 in a posture parallel to the main optical path LM. The optical path of the laser beam LB that is reflected by the half mirror 33 and sent out in a posture parallel to the main optical path LM is referred to as a sub optical path LS. The R (red) laser light source 13R is configured as a semiconductor laser type, and the G (green) and B (blue) laser light sources 13G and 13B are configured as a solid-state laser type.

  The polygon mirror 16 has a structure that rotates at a rotational speed corresponding to the frequency of the drive signal by supplying a drive signal to the mirror motor 17, and as shown in FIGS. The polygon mirror 16 is formed with a plurality of mirror surfaces 16M by finishing the outer peripheral surface, which is a regular polygon when viewed in the direction along the axis Y, into a flat mirror surface. The fθ lens group 18 is composed of a plurality of cylindrical lenses, and a laser beam LB that is equiangularly scanned (scanned at a constant angular velocity) in the main scanning direction by the rotation of the polygon mirror 16 is applied to the photosensitive surface of the photographic paper P at a constant velocity. It functions to convert to a laser beam LB that scans (scans at a constant linear velocity).

  In this optical system, the laser beam LB from the laser light source 13 is converted into a pair of laser beams LB and LB in a parallel posture by the beam converter A (laser beam LB sent to the main optical path LM and the sub optical path LS). The pair of laser beams LB and LB are reflected by the mirror surface 16M of the polygon mirror 16 and then guided onto the photosensitive surface of the photographic paper P at the exposure position X, so that the photosensitive surface of the photographic paper P is adjacent in the sub-scanning direction. The exposure is performed according to the positional relationship. Specifically, as described with reference to FIG. 5 in the first embodiment, the two laser beams LB and LB are set in a positional relationship adjacent to each other in the sub-scanning direction, and the photographic paper P is already exposed. The exposure positional relationship is set so that the area EL to be exposed next overlaps slightly in the sub-scanning direction with respect to the area EP.

  With this configuration, when performing the exposure process, image data of the three primary colors R (red), G (green), and B (blue) constituting one frame is formed in the semiconductor memory (RAM) 3. After a process of developing a bitmap structure having 8-bit density data for one storage area is performed in advance, the polygon mirror 16 is rotated at a set rotational speed by the driving force of the mirror motor 17 and is synchronized with this rotation. By driving the transport motor 1 at the speed, the transport of the photographic paper P is started, and power is supplied to the three types of laser light sources 13 to emit light. When the photographic paper P reaches a position where it can be exposed by this conveyance, each of R (red), G (green), and B (blue) is detected at a predetermined timing when the synchronous sensor 20 detects the laser beam. From the image data, the density data of the line-shaped region located at the head of the image data is sequentially read out, and the modulator 14R is controlled based on the density data of R (red) based on the density data, and the G (green) The modulator 14G is controlled based on the density data, and the modulator 14B is controlled based on the B (blue) density data, thereby controlling the light amounts of the laser beams LB and LB with respect to the photographic paper P. The exposure is performed in a line shape along the scanning direction.

  That is, the light amount of the laser beam LB emitted from the single laser light source 13 is controlled by the modulator 14, the beam converter A generates a pair of laser beams LB and LB, and the laser beam LB is adjacent in the sub scanning direction by the optical system. Since it is guided to the photosensitive surface of the photographic paper P due to the positional relationship, even if exposure without reducing the resolution in the main scanning direction is performed and the conveyance speed of the photographic paper P fluctuates, a linear pattern is formed between the exposed areas. Thus, a good quality image can be formed without forming a gap. In particular, in this exposure apparatus, only by providing the beam converter A, it is possible not only to change the conventional exposure apparatus largely, but also to form a good quality image.

[Another embodiment]
In addition to the above-described embodiment, the present invention may be configured as follows (in this another embodiment, the same number and code as those of the embodiment are given to those having the same functions as those of the above embodiment). Attached).

(A) The exposure may be performed using three or more laser beams LB.

(B) In the first embodiment, the pair of laser beams LB and LB can be irradiated in the sub-scanning direction adjacent to each other at the exposure position X by setting the postures of the pair of beam mirrors. A configuration in which the mirror surface of the polygon mirror is not formed in an inclined posture may be employed. In addition, by setting the angle of at least one of the optical axes from the pair of laser light sources 13 and 13 to the photographic paper P, a configuration is adopted in which the posture of the beam mirror is not set and the mirror surface of the polygon mirror is not formed in an inclined posture. It is also possible to do.

(C) In the first embodiment, the same image data is exposed by the two laser beams at the same timing. However, as shown in FIG. 9, the timing at which the two laser beams expose the photographic paper P is different. It is also possible to perform exposure so as to produce.

The top view which shows typically the structure of the exposure unit of 1st Embodiment The perspective view which shows the structure of the exposure unit of 1st Embodiment 1 is a side view schematically showing a path of a laser beam according to a first embodiment. The block diagram which shows the exposure control system of 1st Embodiment The figure which shows the exposure form by the laser beam of 1st Embodiment The top view which shows typically the structure of the exposure unit of 2nd Embodiment The figure which shows the structure of the beam converter of 2nd Embodiment. The perspective view which shows the structure of the exposure unit of 2nd Embodiment. The figure which shows the exposure form of another embodiment (c)

Explanation of symbols

13 Light emitting means / laser light source 14 Modulator 16 Polygon mirror 16MT, 16MD Mirror surface 23A Light quantity control means 31 Beam splitter 32, 33 Mirror A Beam converter P Photosensitive material LB Laser beam LM Main optical path

Claims (4)

An exposure apparatus that exposes a photosensitive material conveyed in a sub-conveying direction by reflecting a laser beam from a light emitting means on a rotary polygon mirror and scanning in a main scanning direction,
The light emitting means includes a plurality of laser light sources that emit laser beams, and includes a modulator that independently controls the light amount of the laser beams from the plurality of laser light sources, and the light amount is controlled by each modulator. An optical system for irradiating the photosensitive material with a positional relationship adjacent to the photosensitive material in the sub-scanning direction, and a plurality of modulators for controlling the light amounts of the plurality of laser beams irradiated with the adjacent positional relationship. An exposure apparatus comprising a light amount control means for controlling with the same image data.   A pair of laser light sources corresponding to three light sources of three primary colors of R (red), G (green), and B (blue), and the optical system sent out in parallel from the pair of laser light sources 2. An exposure apparatus according to claim 1, further comprising: the polygon mirror having a mirror surface set in a posture so as to guide a beam to a positional relationship adjacent to each other in the sub-scanning direction on the photosensitive surface of the photosensitive material. An exposure apparatus that exposes a photosensitive material conveyed in a sub-conveying direction by reflecting a laser beam from a light emitting means on a rotary polygon mirror and scanning in a main scanning direction,
The light emitting means is composed of a laser light source that emits a laser beam, and includes a modulator that controls the amount of the laser beam from the laser light source, and generates a plurality of laser beams from the laser beam from the modulator; and An exposure apparatus comprising a beam converter that sends out each laser beam in an adjacent parallel posture, and an optical system that sets the adjacent direction of the pair of laser beams sent out from the beam converter as a sub-scanning direction.   The beam converter includes a beam splitter that branches a laser beam sent out along a main optical path, and a mirror that sends out the laser beam branched by the beam splitter as a pair of laser beams adjacent to the main optical path in a posture parallel to the main optical path, or The exposure apparatus according to claim 3, comprising a prism.

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