JP3493726B2 - Laser light scanning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam scanning apparatus for displaying, recording, and reading information such as images and characters using a laser beam. 2. Description of the Related Art Laser printers, laser facsimile machines,
2. Description of the Related Art A laser beam scanning device such as a laser display scans a laser beam emitted from a laser light source with a rotating polygon mirror such as a polygon mirror and condenses the laser beam on a paper surface. Hereinafter, a conventional laser beam scanning device will be described. FIG. 4 is a perspective view of a conventional laser beam scanning device. In the figure, reference numeral 1 denotes a laser light source.
Irradiates the polygon mirror 2 with laser light. The polygon mirror 2 is driven by a motor 3 to rotate, and performs polarization scanning of the laser light. A condenser lens 4 is provided on the side of the polygon mirror 2, and the condenser lens 4 condenses the laser light on the surface of the paper 5 to be scanned. A synchronization sensor 6 is provided on the side of the scanned paper 5, and a polygon mirror 2 is provided.
The laser light reflected by the light enters the synchronous sensor 6. Reference numeral 7 denotes a storage box in which the paper 5 to be scanned is stored. The paper 5 to be scanned is located above the storage box 7 (in the Y direction).
Sent to The paper 5 to be scanned is sandwiched between a main roller 8 and an idle roller 9, and is fed at a constant speed in the Y direction by driving the motor 10 and rotating the main roller 8. A platen roller 11 is provided on the back surface of the scanned paper 5 at the laser light condensing position, and the scanned paper 5 travels while sliding on the platen roller 11. A sensitive material or the like is applied to the paper surface of the scanned paper 5, and a desired image or character is formed by the incidence of the laser beam. Here, the printing start position L on the surface to be scanned has a mechanical structure determined by an electric signal based on the time from the point when the laser beam is incident on the synchronous sensor 6. [0005] By the way, the scanned paper 5 fed by the main roller 8 and the idle roller 9 is
The print start position L also changes in proportion to the skew amount or the meandering amount because the printing start position L is liable to skew or meander in the horizontal direction (X direction). This change adversely affects the overlay accuracy of printed matter. For example, in the printing process in the printing field, in the case of form printing and color printing, the overlay accuracy of printed matter is said to be 50 μ or less, and printing position deviation due to skew and meandering is caused by moiré and character in the subsequent printing process. This has a serious adverse effect on misregistration and the like, resulting in a problem of deteriorating printing quality. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to provide a laser beam scanning apparatus free from a printing start position shift. For this purpose, a laser beam scanning apparatus according to the present invention has a platen roller on which a scanned paper slides and is slidably disposed in a direction perpendicular to the paper feeding direction. Is slid integrally with the platen roller in conjunction with the platen roller. According to the above arrangement, when the scanned paper is skewed or meandered, the synchronous sensor slides in the horizontal direction in conjunction with the skew, so that the printing start position does not shift. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a laser beam scanning device according to an embodiment of the present invention, FIG. 2 is a partial sectional view of the same, and FIG. 3 is a partial side view of the same. In FIG. 1, 1 is a laser light source, 2 is a polygon mirror, 3 is a motor, 4 is a condenser lens, 5 is a paper to be scanned,
7 is a storage box, 8 is a main roller, 9 is an idle roller,
Reference numeral 10 denotes a motor. The above members are the same as those in the conventional example, and the description is omitted. Next, the arrangement of the platen roller and the synchronous sensor will be described. 12 is a platen roller,
It is rotatably supported by a rotating shaft 13. Both sides of the rotating shaft 13 are supported by bearings 14.
Is slidable in its axial direction (X direction), that is, in a direction orthogonal to the paper feed direction of the scanned paper 5. A mounting plate 15 is fixed to one end of the rotating shaft 13, and a synchronous sensor 16 is mounted on the mounting plate 15. Both ends of the platen roller 12 are fixed to the rotating shaft 13 by a stopper 17, so that the platen roller 12, the rotating shaft 13, and the synchronization sensor 16 slide in the X direction integrally and interlocked. In FIG. 3, the scanned paper 5 travels in the Y direction while rotating around the platen roller 12 at a small angle θ. The platen roller 12 has a high friction coefficient with the paper 5 to be scanned. Therefore, the paper 5 to be scanned and the platen roller 12
A large frictional force is generated between them, and the platen roller 12 rotates about the rotation shaft 13 as the scanned paper 5 travels in the Y direction. Synchronous sensor 16 integrated with 12 also slides in the same direction. Here, the printing start position L on the surface to be scanned is
The print start position L is always fixed since the synchronous sensor 16 slides integrally with the platen roller 12 while being determined by an electric signal based on the time from when the laser beam enters the synchronous sensor 16. be able to. As described above, according to the present invention, a synchronous sensor for receiving a laser beam by arranging a platen roller with which a scanned paper slides in a sliding manner in a direction perpendicular to the paper feeding direction is provided. Since the paper is slid integrally with the platen roller, the printing start position is always kept constant even if the scanned paper is skewed or meandering, so that the printing repeatability can be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a laser beam scanning device according to one embodiment of the present invention. FIG. 2 is a partial cross-sectional view of the laser beam scanning device according to one embodiment of the present invention. FIG. 4 is a perspective view of a conventional laser light scanning device. [Description of References] 1 Laser light source 2 Polygon mirror 4 Condensing lens 5 Scanned paper 12 Platen roller 13 Rotation Axis 16 Synchronous sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-230050 (JP, A) JP-A-6-59205 (JP, A) JP-A-63-279219 (JP, A) JP-A-62 204221 (JP, A) JP-A-62-169179 (JP, A) JP-A-2-41219 (JP, U) JP-A-59-106257 (JP, U) JP-A-61-99120 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/44

Claims (1)

(57) Claims: 1. A laser light source, a rotary polygon mirror for polarizing and scanning the laser light emitted from the laser light source, and a laser beam scanned by the rotary polygon mirror on a paper to be scanned. A condensing lens for condensing light on the paper surface, a platen roller slidably arranged in a direction perpendicular to the paper feeding direction of the scanned paper, and a back surface of the scanned paper; A laser light scanning device comprising: a synchronous sensor that receives the laser light reflected by the rotary polygon mirror by sliding integrally.