JPH043311Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document scanning device used to reciprocate a moving optical system for reading document images in an image forming apparatus such as a copying machine.

In recent years, the original image is read by a solid-state photodetector such as a CCD and converted into an electrical signal. Next, a laser corresponding to this electrical signal is irradiated onto the photosensitive drum to form an electrostatic latent image, which is then developed and converted into an electrical signal. Technology to reproduce images,
Techniques have been developed for reproducing images by operating well-known recording devices such as thermal heads and ink jets using the above electrical signals. The method of converting the original image into an electrical signal and reading it involves enlarging/reducing the image,
It has a very wide range of applications because it can perform electrical processing such as negative/positive reversal or mirror image creation.

In such an image forming apparatus, the moving optical system that reads the original image must move smoothly and without vibration.

The present invention satisfies the demand for a moving optical system equipped with such a wire-type drive device and provides a document scanning device that moves this moving optical system smoothly and stably.

In order to achieve such an objective, the document scanning device according to the present invention includes a scanning means for scanning a document;
A guide means for guiding the scanning means along a fixed trajectory, a drive shaft provided in engagement with the main body of the device for moving the scanning means along the guide means, and a spiral provided on the drive shaft. 1st with groove
and a second drive pulley, a first wire that is wound around the spiral groove of the first drive pulley, is locked to one end of the scanning means, and is stretched parallel to the guide means; a second wire wound around the spiral groove of the two drive pulleys, locked to the other end of the scanning means, and stretched parallel to the guide means; In a document scanning device that moves the scanning means by moving the first and second wires via a drive pulley, the drive shaft includes a screw for being movable in the axial direction at an engagement portion with the device body. The lead direction and pitch of the threaded portion are the same as the winding direction and pitch of the helical grooves of the first and second drive pulleys, respectively.

The present invention will be described in detail below, taking as an example a document scanning device used for reading document images in an image forming apparatus.

In Figures 1 to 3, 1 is the outer box of the main body of the device;
Reference numeral 2 designates a document table glass on which a document is placed, and reference numeral 3 designates a reciprocally movable document illumination unit which is built into the outer box 1 and serves as a scanning means for scanning the document.
The document illumination unit 3 includes a housing 4, two fluorescent light sources 5, a first mirror 6 that receives reflected light from the document surface, a second mirror 7 that bends the light from the first mirror in the horizontal direction, and a second mirror. It consists of a lens 9 and the like that converges the reflected light and forms an image on the light receiving surface of the fixed light receiving element 8. Here, three sets of optical systems each consisting of a solid-state light-receiving element 8 and a lens 9 are provided in the housing 4 to read the original at high resolution. At the back of the solid-state light receiving element 8, there is an adjustment table 10 for adjusting the position, angle, etc. of the light receiving element.
is provided.

Optical rails 13 and 14 serving as guide means for guiding the document illumination unit 3 are provided between the left side plate 11 and the right side plate 12 of the outer box 1. A block metal fitting 15 is fixedly attached to the rear end of the document illumination unit 3, and an optical rail 13 fits into a guide hole 16 drilled in the lower part of the block metal fitting 15 to smoothly slide and hold the illumination unit 3. Original illumination unit 3
Two bearings 17 having semicircular bearing surfaces are provided at the front end of the optical rail 14, and these bearings 17 slide on the upper surface of the optical rail 14. The bearing 17 can be slightly slid against the housing 4 in a direction perpendicular to the axis of the optical rail 14. This helps the document illumination unit to move back and forth smoothly. A driving means is provided for reciprocating the document illumination unit, and this driving means will be explained in detail below.

Block hardware 1 on one end side of the lighting unit 3
One end of a wire 18 is fixed to the upper surface of 5 by a terminal 19. The wire extends from here to the right and wraps around the first drive pulley 21 from above in a left-handed manner. This pulley has a counterclockwise spiral groove cut into its surface, and the wire is wound several times along this groove, and part of the wire is wrapped around a narrow fan-shaped notch hole cut into the groove of the pulley. Fixed. This fixing method will be explained later. The wire coming out from the bottom of the pulley 21 passes under the block hardware 15, is bent at a right angle by the lower deflection pulley 22, and is then passed through the take-up pulley 23.
It wraps around counterclockwise from below and exits from above. This wire is bent again at right angles by the upper deflection pulley 24 and its end is suspended via a tension spring 25 to one end of the terminal 19. The rotation axes of the lower deflection pulley 22 and the upper deflection pulley 24 are connected to a wire portion 18a passing over the block hardware 15 and a wire portion 18b passing below.
is parallel to the optical rail 13, and is offset so that the wire is deviated in the direction of the optical rail by the width a of the wire wound around the take-up pulley 23.

The two deflection pulleys 22 and 24 are rotatably attached to the left side plate 11 by a mounting plate (not shown). The take-up pulley 23 is connected to a motor 27 via an electromagnetic clutch 26. motor 27
The wire 18 is wound up by forward and reverse rotation.

On the other hand, a wire 29 fixed to the other end of the lighting unit 3 by a terminal 28 extends rightward and is wound around the second drive pulley 30 from above in a left-handed manner. This pulley also has a counterclockwise spiral groove cut on its surface.
The wire is wrapped multiple times along this groove, and
A part of it is fixed in a narrow fan-shaped notch hole cut into the groove of the pulley. This fixing method will be explained later. The wire coming out from below the pulley 30 passes under the front end of the housing 4, and its direction can be changed by 180° by a deflection pulley 31 rotatably provided on the left side plate 11. This wire end is suspended from one end of the terminal 28 via a tension spring 32. Deflection pulley 3
1 is a wire portion 29 passing above the front end of the housing.
a and the wire portion 29b passing under the optical rail 1
It is rotatably attached to the left side plate 11 in a state where it is tilted parallel to 4.

Next, the first drive pulley 21 and the second drive pulley 3
The drive shaft 33 with 0 attached is attached to the support arm 3 near the pulley.
4 and 35 on the right side plate 12. The drive shaft 33 is rotatably and axially slidably supported by a slide bearing 36 (FIG. 4).

Here, a method of fixing the wire 18 and the first driving pulley 21 and the method of fixing the wire 29 and the second driving pulley 30 will be explained. As shown in Figures 5, 6 and 7, each drive pulley has four wires running along a right-handed helical groove.
It has half a roll wrapped around it.

Fan-shaped cutout holes 37 and 38 are provided approximately in the widthwise center of the drive pulley along the spiral groove. The width of the notched holes 37 and 38 is larger than the wire diameter and slightly narrower than the spiral groove width. The cutout hole is a round hole 3 made on the side of the pulley.
9 is conducting. Figure 6 shows this cutout hole 38.
The upper part of the round hole 39 is removed so that the fixed part of the wire can be seen. As can be seen from this figure, a screw 40 is screwed into the back of the round hole 39, the wire 29 is wound around the screw 40 half a time, and the wire is held down by the cap of the screw 40.
FIG. 7 shows this state viewed from the front. Entrance portions 38a and 38b of the cutout hole 38 are arcuate to prevent stress from concentrating on the wire 29 and damaging it. The method of fixing the wire 18 and the first drive pulley 21 is also the same as the method described above, so the explanation will be omitted.

In this way, by having a wire that is locked at one end of the document illumination unit 3 and a wire that is locked at the other end, and by fixing the wire and the drive pulley, the relative position of the wire and the drive pulley can be kept constant. Therefore, if the document illumination unit 3 is first adjusted so that it can move smoothly along the rails 13 and 14, the illumination unit 3 will slide smoothly and without vibration even after many reciprocating movements. death,
The relative positions of both ends of the document illumination unit 3 are always kept constant.

If the wire is not fixed to the drive pulley,
After reciprocating many times, the relative position of the wire and the drive pulley at both ends of the drive shaft 33 deviates, and the lighting unit 3
optical scanning may not be performed smoothly. In particular, when the illumination unit 3 is configured to fit and slide on the rail 13 through the guide hole 16 as in this embodiment, the wires 18, 29 and the drive pulley 21,
If the relative position of the illumination unit 30 shifts, smooth movement of the illumination unit 3 becomes difficult. A threaded portion 41 having a left-hand thread is fixedly provided at the center of the drive shaft 33 (FIG. 8). A nut 42 is screwed into this threaded portion. The nut 42 is attached to the drive shaft 33 with respect to the mounting arm 43.
It can be moved slightly in the direction perpendicular to the , and is fitted backwards so that it does not rotate. This makes the rotation of the drive shaft 33 smooth. The thread leads of the threaded portion 41 and the nut 42 are the same as the pitch of the helical grooves on the surfaces of the first drive pulley 21 and the second drive pulley 30.

Since the drive shaft 33 has the above configuration, when the document illumination unit 3 moves from left to right to read the document, the drive shaft 33 rotates clockwise, and the wires 18 and 29 are connected to the first drive pulley 21 and the second drive pulley, respectively. The surface of the drive pulley 30 is moved from bottom to top, but at this time, the drive shaft 33 moves from top to bottom by the same distance as the wire due to the action of the threaded part 41 and nut 42, so it The position of the wire is always constant. That is, regardless of the position of the original illumination unit 3, the wire and the rail are parallel to each other.

As can be seen from the above description, the illustrated drive device connects the ends of the two wires 18 and 29, respectively, to the document in order to drive the document illumination unit 3, which is arranged to reciprocate on a fixed trajectory. These wires 18 and 29 are wound around the first and second drive pulleys 21 and 30 in the middle, and these wires are connected to the motor via the electromagnetic clutch 26. 27, thereby causing the document illumination unit 3 to reciprocate. The driving pulleys 21 and 30 are provided with notched holes 37 and 38, which are slightly wider than the diameter of the wire, approximately at the center of the winding periphery, and the wire is fixed with a screw 40. There is. Therefore,
First, the document illumination unit 3 smoothly slides onto the rail 1.
If the relative position of the wire and drive pulley is determined so that it can slide along lines 3 and 14 and fixed with screws, the relative position of the wire and drive pulley will shift after reciprocating many times. There is no danger that smooth movement will not be possible.

Further, the first and second driving pulleys are fixedly installed on the same shaft, and around the first and second driving pulleys, spiral grooves are provided in the same direction for winding the wire at regular intervals. Since the wire is slid in the axial direction so that the starting position of the wire does not shift from side to side, the position of the wire with respect to the rails 13 and 14 is always constant, that is, regardless of the position of the document illumination unit 3. The wires and the rails are therefore parallel, so that the lighting unit is always moved smoothly and without any vibrations. Therefore, reliable and stable document reading is possible.

Such a document scanning device can be particularly advantageously applied to a moving optical system that reads document images in an image forming apparatus, but can also be applied to other devices that require particularly smooth movement.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a plan view of the device shown in FIG. 1, FIG. 3 is a perspective view of the device shown in FIG. 1, and FIG. is a partially enlarged view of the vicinity of the first drive pulley in Fig. 2, and Fig. 5 is a partially enlarged view of the vicinity of the first drive pulley in Fig. 2.
A perspective view showing how to fix the wire and drive pulley,
Fig. 6 is a partial sectional view clearly showing the wire fixing part in Fig. 5, Fig. 7 is a front view of the part shown in Fig. 6 seen from the screw side, and Fig. 8 shows the drive shaft, threaded part, and nut. FIG. 2 is an enlarged view of a portion made up of parts, in which a is a plan view thereof and b is a side view thereof. DESCRIPTION OF SYMBOLS 1...Outer box of the apparatus main body, 2...Document table glass, 3...Document illumination unit, 4...Housing, 5...Light source, 6...First mirror, 7...Second
Mirror, 8...Solid light receiving element, 9...Lens, 1
0...Adjustment table, 11...Left side plate of outer box, 12...
...Right side plate of the outer box, 13...Optical rail, 14...
...Optical rail, 15...Block hardware, 16...
Guide hole, 17...Bearing, 18...Wire, 19
... terminal, 21 ... first drive pulley, 22 ... lower deflection pulley, 23 ... take-up pulley, 24 ...
Upper deflection pulley, 25... tension spring, 26... electromagnetic clutch, 27... motor, 28... terminal, 2
9... Wire, 30... Second drive pulley, 31...
... Deflection pulley, 32 ... Tension spring, 33 ... Drive shaft, 34 ... Support arm, 35 ... Support arm, 36 ...
...Slide bearing, 37...Notch hole, 38...
Notch hole, 38a... Notch hole, 38b...
Notched hole, 39...Round hole, 40...Screw, 41
...Screw part, 42...Nut part, 43...Mounting arm.

Claims (1)

[Claims for Utility Model Registration] A scanning means for scanning a document, a guiding means for guiding the scanning means along a fixed trajectory, and a device engaged with the main body for moving the scanning means along the guiding means. a drive shaft provided on the drive shaft; first and second drive pulleys provided with a helical groove provided on the drive shaft; and a drive pulley wound around the helical groove of the first drive pulley and engaged with one end of the scanning means. a first wire that is stopped and stretched parallel to the guide means;
a second wire wound around the spiral groove of the second drive pulley, locked to the other end of the scanning means, and stretched parallel to the guide means; In the document scanning device in which the scanning means is moved by moving the first and second wires via two drive pulleys, the drive shaft is movable in the axial direction at the engagement portion with the device main body. A document scanning device comprising a threaded portion, the lead direction and pitch of the threaded portion being the same as the winding direction and pitch of the helical grooves of the first and second drive pulleys, respectively.