JP2701938B2 - Driving mechanism of scanning optical system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive mechanism for a scanning optical system of an image forming apparatus such as a copying machine.

2. Description of the Related Art Conventionally, in a driving mechanism of a scanning optical system of a copier, which reciprocates under a transparent platen and scans a document surface to guide an image of the document to a photosensitive drum, a driving mechanism of the scanning optical system is used. An abnormality in the state is detected by a switch or the like, and stop control of the drive motor of the scanning optical system is performed by a detection signal of the switch.

That is, the stop position (scanning start position) on the upstream side of the scanning optical system is arranged upstream from the scanning start point of the document so as not to scan the document in an unstable driving area when the drive motor rises. I have. The downstream stop position (scan end position) is located downstream of the original scan end point in order to prevent the original from being scanned in an unstable drive area when the drive motor rises. Further, a switch such as a limit switch for detecting an abnormality in the driving state of the scanning optical system is provided at a suitable position on the upstream side of the upstream stop position. In addition, a switch for detecting an abnormality is provided at an appropriate position further downstream than the downstream stop position on the scanning end point side of the scanning optical system.

The scanning of the scanning optical system reciprocates between the upstream stop position and the downstream stop position, but when the scanning optical system abnormally moves beyond the upstream stop position or the downstream stop position, the switch is turned off. However, when this is detected, the drive motor of the scanning optical system is immediately stopped to prevent damage to the device due to runaway of the scanning optical system.

[Problems to be solved by the invention]

By the way, in the conventional driving mechanism of the scanning optical system, an abnormal movement state of the scanning optical system is detected by a switch, and the driving motor of the scanning optical system is stopped by the detection signal. Even in a normal operation, the drive motor may be stopped or an abnormal state may not be detected due to a failure of the switch, and damage to the device may not be reliably prevented.

The present invention has been made in view of the above problems, and has as its object to provide a driving mechanism for a scanning optical system that can reliably stop abnormal operation of the scanning optical system and prevent damage to equipment. .

[Means for solving the problem]

In order to solve the above-described problems, the present invention provides a driving mechanism for a scanning optical system in which a scanning optical system reciprocates on a guide rail by rotating a wire drum around which a wire is wound. Is set so that the set allowable movement amount of the scanning optical system and the length of the wire wound on the wire drum match,
The center of the wire wound around the wire drum when the scanning optical system is at the center of movement is fixed to the wire drum.

[Action]

In the driving mechanism of the scanning optical system configured as described above, when the wire drum is rotated from the wire winding end of the wire drum to one wire winding end of the wire drum, the scanning optical system is set. Move within the specified allowable movement range. When the wire drum is rotated and the wire fixing point comes to the wire winding end of the wire drum, the previously released wire and the wound wire are wound together on the wire drum. The scanning optical system is stopped at the limit point of the permissible moving range by the winding operation of (1).

〔Example〕

FIG. 8 is a configuration diagram of a copying machine (image forming apparatus) using the driving mechanism of the scanning optical system according to the present invention. In the figure, a copying machine F has a contact glass 51 and a document holder 52 on its upper surface, and has an optical mechanism L and an image forming means P inside.

The optical mechanism L includes a first optical system 2 and a second optical system 3 provided in a driving device 1 described later, a lens unit 53 fixed to a copying machine main body 50, and a reflecting mirror 54. The first optical system 2 includes a light source 21 such as a halogen lamp and a reflector 22.
The second optical system 2 includes a reflecting mirror 31 and a reflecting mirror 32. Both the first optical system 2 and the second optical system 3 are configured to be able to reciprocate in the R direction along guide rails 4, 4 '(see FIG. 1). The light from the light source 21 is reflected by the original G on the contact glass 51,
After being guided to the lens unit 53 via 23, 31, 32, the light is reflected by the reflecting mirror 54 toward the photosensitive drum 55. With this configuration, the contents of the original G are exposed on the photosensitive drum 55 by the scanning optical system including the first optical system 2 and the second optical system 3 scanning the original G.

The image forming means P includes a transfer mechanism, a paper feed mechanism and a paper discharge mechanism, and the transfer mechanism includes a photosensitive drum 55, a charging device 56, a blank lamp 57, a developing device 58, a transfer device 59, a separation device 60, It comprises a cleaning device 61 and the like. The sheet feeding mechanism is composed of a plurality of sheet feeding cassettes 62 and 62 ', sheet feeding rollers 63 and 63', conveying roller pairs 64 and 65, and registration roller pairs 66 in order from the upstream side in the feeding direction. Is composed of a conveyor belt 67, a fixing device 68, a discharge roller 69, and a paper discharge tray 70. The electrostatic latent image exposed on the photosensitive drum 55 by the optical mechanism L is transferred to a sheet fed by the sheet feeding mechanism, and the transferred sheet is discharged by the sheet discharging mechanism.

FIG. 1 is a perspective view of the driving device 1 for the scanning optical system. In the figure, wires 9, 9 'on both lateral sides of guide rails 4, 4' are connected from upstream fixed ends 10, 10 'to downstream fixed ends 11, 11' at both ends of the second optical system 3. Provided movable pulleys 33, 33 ', fixed pulleys 5, 5', wire drums 6,
It is stretched through 6 '. A first optical system 2 integrally comprising a light source 21, a reflection plate 22, and a reflection mirror 23 is a supporting member at both ends.
The wires 9, 9 'are slidably mounted on the guide rails 4, 4' via 25, 25 'and the wires 9, 9' are fixed to wire fixing portions 24, 24 'provided on the support members 25, 25'. I have. Further, a second mirror in which the reflecting mirror 31 and the reflecting mirror 32 are integrally formed.
An optical system 3 is slidably mounted on guide rails 4, 4 'via support members 34, 34' at both ends.

As shown in FIG. 2, the wire drum 6 is provided with a slit-like groove 6b having a columnar groove 6c at the center thereof, and is axially bored from the wire drum side surface 6a to about 1/2 of the drum width. ing. At a predetermined position of the wire 9, a fixing member 12 having a diameter substantially equal to the diameter of the cylindrical groove 6c is fixed, and the fixing member 12 is fitted into the cylindrical groove 6c, and the wire 9 is fixed. Are fixed to the wire drum 6.

FIGS. 3 and 4 are a front view and a side view showing a state where the wire 9 is fixed and wound on the wire drum 6, respectively. The wire 9 is wound around the wire drum 6 by a predetermined amount as described later. When the fixed point of the wire 9 is the wire winding end of the wire drum 6, the wire drum 6 cannot be further rotated. Note that the wire 9 may be fixed to the wire drum 6 by, for example, crimping the wire 9 on a wire winding surface of the wire drum 6 with a screw or a stud. The wire 9 'is also fixed and wound on the wire drum 6' in the same configuration as described above.

Returning to FIG. 1, the wire drums 6 and 6 'are connected by a connecting rod 7, and a drive gear 8 is fixed to the wire drum 6'. By transmitting the rotational force of a drive motor (not shown) to the drive gear 8, the wire drums 6 and 6 'rotate at the same time, and the winding operation of the wires 9, 9' is performed. And the second optical system 3 is a guide rail 4,
Reciprocate on 4 '. That is, when the wire drums 6, 6 'are driven forward (in the direction D2 in the figure), the upper wire of the wires 9, 9' is wound up, and the lower wire is released.
The first optical system 2 and the second optical system 3 are guide rails 4,
When the wire drums 6, 6 'move in reverse on the downstream side (direction D1 in the figure) above 4', the wires above the wires 9, 9 'are released, and the lower wires 9, 9' are released. Since the first optical system 2 and the second optical system 3 are wound, the first optical system 2 and the second optical system 3 move to the upstream side (the direction opposite to D1). At this time, the moving speed of the movable pulleys 33, 33 'due to the winding operation of the wires 9, 9' becomes 1/2 of the winding speed of the wires 9, 9 '. 2 in 1
It will move at a speed of / 2.

The driving mechanism of the scanning optical system using a wire may be provided on one of both ends of the scanning optical system.

Next, the relationship between the amount of winding of the wires 9, 9 'by the wire drums 6, 6' and the amount of movement of the scanning optical system will be described. 5 to 7 are diagrams showing the relationship between the amount of winding of the wire 9 by the wire drum 6 and the amount of movement of the scanning optical system. For convenience of explanation, the moving amount of the scanning optical system is indicated by the moving amount of the first optical system 2, and in FIGS. 5 to 7, only the first optical system 2 of the scanning optical systems is shown. The configuration of the second optical system 3 is omitted.

5 to 7, point A is the scanning start point of the original,
Point A 'is the maximum scanning end point of the document. That is, the distance AA 'is a distance corresponding to the maximum size of the document G.
Point H is the scanning start point of the first optical system 2, and point H 'is the scanning end point of the first optical system 2. For example, when the first optical system 2 reaches the points A and A ', the moving state is detected by a switch or the like, and the stop signal or the inversion driving of the drive motor is controlled by the detection signal. The points H and H 'are positions where the first optical system 2 stops due to the stop operation or the reverse drive of the drive motor. Further, the distance HH ′ is the maximum distance that the first optical system 2 moves in normal scanning. The distance HA is provided as a distance from the start of the movement of the first optical system 2 to a stable movement state, and the distance A′−
H 'indicates that the first optical system 2 has finished scanning the original and the first optical system 2
Is provided as the distance until the return to the scanning start point H and the return stop. Point E is a limit point at which the first optical system 2 can move on the original scanning start point A side, and point E 'is a limit point at which the first optical system 2 can move on the original scanning end point A' side. That is, when the first optical system 2 moves further upstream (left side in the figure) or downstream (right side in the figure) beyond that point, the scanning optical system moves to the points E and E '.
This is the limit point at which there is a risk of collision with 50 structures (not shown) and damage to the equipment. Therefore, the distance EE ′ is equal to the first optical system 2.
Is the allowable movement range. M is the distance EE '
Is the center of movement of the first optical system 2.

FIG. 5 is a diagram showing the relationship between the wire drum 6 and the wire 9 when the moving center Q of the first optical system 2 is at the point M. FIG. 6 is a diagram showing the relationship between the wire drum 6 and the wire 9 when the moving center Q of the first optical system 2 is at the point E,
FIG. 7 is a view showing the relationship between the wire drum 6 and the wire 9 when the movement center Q of the first optical system 2 is at the point E '.

In FIG. 5, the wire 9 is fixed to the wire drum 6 at the center K of the wound wire length. K is a fixing point of the wire 9. Also, in FIG.
In a state in which the fixed point K of the wire 9 has reached the upper end of the wire winding of the wire drum 6, and in FIG. Has reached the wire winding lower end of the wire drum 6. Therefore, the wire 9 wound around the wire drum 6
Is adjusted to be equal to the distance EE ′, and the first optical system 2 can be moved only within the set movement range EE ′ by the winding operation of the wire 9 by the wire drum 6. Is configured.

Next, an abnormal operation of the scanning optical system in the driving mechanism of the scanning optical system will be described.

As described above, the moving range of the first optical system 2 is usually the distance HH '. For example, the failure of a switch for detecting the scanning position of the first optical system 2 and the driving of the driving motor are controlled. When the microcomputer runs out of control, the first optical system 2 moves beyond the scanning start point H of the first optical system 2 and the scanning end point H ′ of the first optical system 2. However, for example,
When the optical system 2 moves further upstream beyond the scanning start point H of the first optical system 2, when all the wires 9 are released from the upper end side of the wire drum 6, the first optical system 2 is moved by the wires 9. Is restricted, the first optical system 2 is stopped at the movement limit point E. That is, in FIG. 6, after all the wires 9 are released from the upper end side of the wire drum 6, the wire 9 is wound up from the lower end side by the reversal drive of the wire drum 6, while the wire 9 is also wound up from the upper end side. Wires 9 from the upper and lower ends.
As a result, the pulling force in both the left and right directions acts on the wire fixing portion 24, and the first optical system 2 is suddenly stopped at the movement limit point E.

Even when the first optical system 2 moves further downstream beyond the scanning end point H 'of the first optical system 2, the same pulling force acts on the wire fixing unit 24 as described above, and the first optical system 2 It will be suddenly stopped at the movement limit point E '.

In addition, by using the wire 9 having an appropriate elastic force, the inertia force of the first optical system 2 due to the sudden stop is reduced by the wire 9.
And the scanning optical system can be reliably stopped. Also, when the scanning optical system stops suddenly,
For example, in a drive motor composed of a DC motor, an overcurrent protection circuit is activated and the drive is automatically stopped, and in a drive motor composed of a stepping motor, the step-out occurs, so that the equipment is not damaged.

〔The invention's effect〕

As described above, according to the present invention, a wire having a wire length equal to the set allowable movement amount of the scanning optical system is wound around the wire drum, and the scanning optical system is moved so as not to exceed the movement limit point. Since the winding operation of the wire of the drum is adjusted, when the scanning optical system reaches the movement limit point due to the abnormal operation, the movement operation of the scanning optical system is stopped by the wire, and it is possible to reliably prevent damage to the device. Also,
Since it is not necessary to provide a switch for detecting abnormal movement of the scanning optical system and its peripheral circuit, the structure can be simplified.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a driving mechanism of a scanning optical system according to the present invention, FIG. 2 is a perspective view of a wire drum, FIG. 3 is a front view of a wire drum wound with wires, and FIG. FIG. 5, FIG. 6, FIG. 7 are side views of the wound wire drum, and FIG. 8 is a diagram showing the relationship between the amount of wire winding of the wire drum and the amount of movement of the scanning optical system, and FIG. FIG. 1 is an overall configuration diagram of an image forming apparatus using a driving mechanism of a scanning optical system. 1 .... Driving device for scanning optical system, 2 .... First optical system, 3 ....
… Second optical system, 4,4 ′… Guide rail, 5,5 ′… Fixed pulley, 6,6 ′… Wire drum, 6a… Wire drum side, 6b… Groove, 6c… Circle Columnar groove, 7, connecting shaft,
8. Drive gear, 9, 9 '... Wire, 10, 10', 11, 11 '...
... Fixed end, 12 ... Fixed member, 21 ... Light source, 22 ... Reflector, 23,31,32,54 ... Reflector, 24,24 '... Wire fixing part, 33,33' ... Movable Pulley, 50 ... Copy machine body, 51 ...
… Contact glass, 52… original holder, 53… lens part, G… original.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Akira Nakakuma 1-2-2, Tamazo, Chuo-ku, Osaka-shi, Osaka Inside Mita Kogyo Co., Ltd. (56) References Japanese Utility Model Application Sho 62-74240 (JP, U)

Claims (1)

(57) [Claims] In a scanning optical system driving mechanism in which a scanning optical system reciprocates on a guide rail by rotating a wire drum around which a wire is wound, the relationship between the wire drum and the wire is determined by the scanning optical system. And the length of the wire wound around the wire drum is set to match, and the scanning optical system is wound around the wire drum when the scanning optical system is at the center of movement. A driving mechanism for a scanning optical system, wherein a center of a wire is fixed to the wire drum.