JP2521727Y2 - Scanning optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to an image forming apparatus such as an electrophotographic copying machine and a scanning optical apparatus in an image reading apparatus. The present invention relates to a shock absorbing member provided for preventing collision of an optical system having an optical path changing mirror that moves the reflected light along the optical axis.

[Conventional technology]

Conventionally, in an image forming apparatus such as an electrophotographic copying machine or an image reading apparatus, a document is placed and fixed on a platen glass,
There is a method of moving a scanning optical device including a light source. A conventional apparatus having a scanning optical apparatus of this type will be schematically described with reference to FIG. 1 by taking an electrophotographic copying machine as an example for convenience of explanation.

An original table 2 made of transparent glass on which an original D is placed is fixed to an upper portion of the copying machine body 1. An exposure lamp 11 and a first mirror are provided below the platen 2 and in the scanning optical device 10.
A first mirror unit 13 having 12 is provided.

The first mirror unit 13 is attached in parallel with the document table 2 so as to be linearly movable in the horizontal direction of the drawing, and optically scans the entire surface of the document D. In the figure, the first mirror unit 13 indicated by a solid line near the left indicates a position at a home position before the start of copying. The first mirror unit 13 indicated by a broken line near the right side of the drawing is
This shows the position where the reversal and return are performed after the exposure scan is completed.

Reference numerals 14 and 15 denote a second mirror and a third mirror, respectively. The second mirror unit 17, which is fixed to the holding body 16 and integrated, holds 1/1 / the first mirror unit 13 so as to maintain a predetermined optical path length. It moves linearly in the horizontal direction at the speed of 2.
Of course, the movement of the second mirror unit 17 moves parallel to the document table 2 in the same manner as the first mirror unit 13 described above.
Both the first mirror unit 13 and the second mirror unit 17 are moved along a guide bar or a guide rail. In the figure, a second mirror unit 17 indicated by a solid line near the left indicates a home position position before the start of copying, and a second mirror unit 17 indicated by a broken line near the center is
This shows a state in which the forward scanning is completed and the reversion is returned.

Document D on platen 2 is illuminated by exposure lamp 11,
The reflected light passes through the slit, and the first mirror 12,
The light enters the main lens 18 following the light path reflected by the second mirror 14 and the third mirror 15, and further enters the photosensitive drum 3 as an image support via the fourth mirror 19.

FIG. 2 shows the first mirror unit 13 and the second mirror unit.
FIG. 17 is an explanatory diagram showing a relative movement position of 17. In the figure, Indicates the moving position of the first mirror unit 13, and <indicates the moving position of the second mirror unit 17.

The first mirror unit 13 starts at the initial position a, accelerates to a position b at which the maximum speed v is reached, and passes through the document exposure start position C at a predetermined speed via the approaching section.
Further, the scanning exposure is continued, the image exposure is completed when the document exposure end point d is reached, the deceleration is started, the reversal point is reached, the forward movement is stopped, and the acceleration for the return is immediately started. To reach a predetermined maximum speed v ', reach the point g while maintaining the speed, start deceleration from there, return to the initial position a, and complete one cycle. In the case of continuous copying, the next cycle is immediately entered and the above operation is repeated.

The second mirror unit 17 is provided with the first mirror unit 13.
Travel at half the speed and half the distance. These two units then start simultaneously, return simultaneously, and return simultaneously. That is, the second mirror unit 17 accelerates between AB,
It decelerates and reverses between BDs, decelerates between DEs and reverses, returns and accelerates between EFs, returns constant speed (V ') between FGs, returns and decelerates between GAs, and stops.

The return deceleration of the second mirror unit 17 is controlled by the drive motor (DC
The motor is controlled by a rapid brake deceleration by timer control and application of a reverse voltage.

[Problems to be solved by the invention]

In recent scanning optical devices, high-speed scanning and miniaturization of the device are demanded. Therefore, the acceleration section (between ab, between ef, AB
And EF) and deceleration sections (de, ga, DE, and GA), and require rapid acceleration and deceleration.

However, as is well known, when an object is accelerated or decelerated, an over-short always occurs due to its inertial force. For example, when an object traveling at a predetermined high speed is suddenly decelerated, the vehicle may overrun beyond a predetermined stop position or may not reach the predetermined position. Variations in the stop position include variations in the driving force of the drive motor (including variations in the applied voltage), deviations in the timing of the start of deceleration, variations in the frictional load of the sliding part of the object, changes in the environmental temperature, and changes in the fitting and lubricant. It is difficult to keep it constant due to changes in

Also in the scanning optical device, the initial return points a, of the first mirror unit and the second mirror unit at the end of one cycle.
A varies.

In the miniaturized scanning optical device, the holding member 16 of the second mirror unit 17 and the wall surface 20A of the housing 20 of the scanning optical device 10 are particularly used.
Since the gap between the second mirror unit 17 and the second mirror unit 17 is set to be small, the second mirror unit 17 may be over-shortened at the time of return and collide with the wall surface 20A, resulting in deformation / damage or incorrect mirror adjustment.

In order to prevent the collision, conventionally, there are provided shock absorbing devices such as an air damper and an oil damper, shock absorbing means by a link mechanism connected to a tension coil spring, and elastic members such as rubber.

However, in these shock absorbing means, if the elastic force is too strong, the rebound of the optical system member (mirror unit) is large, and the optical system member (mirror unit) is stopped at a position returned from the initial return point in the reverse direction, and the subsequent scanning exposure timing control is disturbed. And a mismatch with the timing of the image forming process. On the other hand, if the elastic force of the shock absorbing means is too weak, the shock force at the time of collision cannot be sufficiently absorbed, causing problems such as an adjustment deviation or damage to the optical system members and other devices due to the shock.

Further, since the shock absorbing means is large and expensive, not only is it uneasy to reduce the size and weight of the scanning optical device,
It also increases costs.

[Means for solving the problem]

This invention is to provide a scanning optical device which solves the drawbacks of the conventional shock absorbing means, and reduces the collision force at the time of return of the optical system member to reliably absorb the impact force and reduce the manufacturing cost. It is another object of the present invention to realize a scanning optical device which can reduce the size of the device.

The scanning optical device of the present invention that achieves the above object is an optical system moving type scanning optical device that reciprocates and exposes and scans a document surface, wherein the reciprocating optical system retainer has a device main body during a return stroke. In order to prevent the collision of the holder, an inner surface of the apparatus body which abuts against the rear surface of the holding body is provided with a leaf spring member for absorbing shock which comes into contact first, and an elastic rubber member for absorbing the pressing force of the holding body which is further retracted. A type of cushioning member is provided, and a light pressure contact with the inner surface of the apparatus main body by the compressive force of only the leaf spring member, and a combination of the leaf spring member and the elastic rubber member according to the amount of return displacement of the holding body. It is characterized in that it is configured to change in two stages, that is, a strong pressure welding by a compressive force, and to absorb a return impact of the holding body.

〔Example〕

FIGS. 1 and 3 show a scanning optical device according to the present invention. FIG. 3 is a partial sectional view of the scanning optical system.

In these figures, a leaf spring member 21 having a special shape for absorbing shock according to the present invention is fixed by screws or the like inside a left wall surface 20A of a housing 20 of the scanning optical device 10. FIG. 4 is a perspective view of the leaf spring member 21. FIG.

The leaf spring member 21 is an integrally formed member including a flat mounting surface portion 21A, a curved surface portion 21B wound in a substantially cylindrical shape with a predetermined radius, and a tip portion 21C. The tip portion 21C has a flat small area, faces the mounting surface portion 21A, and forms a parallel gap. The leaf spring member 21 has a thickness of 0.3 to
It is formed by pressing and bending a 0.5 mm stainless steel plate or phosphor bronze plate material.

FIG. 5A is a partially enlarged sectional view of FIG.
An elastic rubber member 22 is bonded and fixed on a mounting surface 21A of a leaf spring member 21 fixed to a wall surface 20A of the housing 20.
The elastic rubber member 22 does not break or crack even when concentrated stress is applied, does not generate residual strain even when a repeated load is applied, and has a desired elastic compressive force, for example, a rubber hardness of 50. Polyurethane rubber having a degree of 60 ° is used.

5 (B) to 5 (D) are cross-sectional views showing the compression process of the leaf spring member 21 and the elastic rubber member 22. FIG. 5B shows that the holding member 16 of the second mirror unit 17 overruns the initial return point A during the return deceleration,
This shows the moment when it collides with and presses against the curved surface portion 21B of 21. At this time, the distance between the holder 16 and the wall surface 20A of the housing 20 is l0. From this state, the leaf spring member 21 starts to be compressed. At this time, the distal end portion 21C of the leaf spring member 21 keeps a no-load initial separation distance from the surface of the elastic rubber member 22.

Next, FIG. 5C shows a state in which the holding body 16 further overruns, returns in the direction of the arrow, and advances to compress the leaf spring member 21 and absorb the impact. Tip of leaf spring member 21
The spring load W of the leaf spring member 21 changes almost linearly with the amount of movement of the holder 16 until 21C reaches the position of the interval 1 where it comes into contact with the surface of the elastic rubber member 22.

FIG. 6 is a characteristic diagram showing the relationship between the amount of movement of the leaf spring member 21 in the direction indicated by the arrow and the compressive load. In the figure, a broken line A1 shown by a solid line is a diagram showing characteristics of the leaf spring, and a broken line A2 is shown.
Is a boundary point where the state shown in FIG. 5 (C) shifts to FIG. 5 (D). A broken line B indicated by a dashed line is a characteristic diagram of a conventional shock absorbing spring or damper, in which the load changes with a substantially constant gradient.

When the holding body 16 is further overrun from the state shown in FIG. 5C and moves forward in the direction indicated by the arrow, the tip 21C of the leaf spring member 21 is moved by the elastic force of the elastic rubber member 2 due to the impact pressure of the holding body 16.
2, the curved surface portion 21B is pressed and deformed to become slightly flat, and the tip portion 21C is
5D, and slides on the surface while being pressed into the surface and comes into the state of the interval l2 shown in FIG. 5 (D). During this process, the load of the leaf spring 21 increases rapidly and the elastic rubber member
The compression force due to the elastic deformation of 22 is accumulated, resulting in an extremely large load W. In the state shown in FIG. 5 (D), the right bent line A2 beyond the bending point P shown in FIG.
Increases significantly.

In this way, when the second mirror unit 17 overruns the initial return point A for some reason and the holder 16 collides with the curved surface portion 21B of the leaf spring member 21, the tip portion 21C contacts the mounting surface portion 21A. In the process shown in FIGS. 5B to 5C before contact, the leaf spring member 21 can buffer the return overrun of the second mirror unit 17 with a light load and absorb the impact. In other words, if the overrun speed (kinetic energy) of the second mirror unit 17 is small, it is possible to gradually absorb the impact in this process, decelerate, and stop.

When the overrun energy of the second mirror unit 17 is large, the buffer between FIGS. 5B to 5C cannot be supported, and the leaf spring member 21 is further pressed and
The elastic rubber member 22 is pressed to advance between FIGS. 5 (C) to 5 (D). During this time, the leaf spring member 21 and the elastic rubber member 22
Is extremely large, the overrunning second mirror unit 17 is rapidly decelerated and stopped at a short distance. That is, when the amount of overrun is large, the elastic force of the leaf spring member 21 first absorbs the impact gently and decelerates it. It can be decelerated and stopped.

In addition, the leaf spring member and the elastic rubber member for shock absorption according to the present invention change the strength in two stages by their displacement, and the shapes are not limited to the above-described embodiment, and various shapes can be used. Can be applied.

[Effect of the invention]

According to the present invention, the scanning optical system unit is overturned or turned off even when returning to the deceleration state by mounting the elastic rubber member together with the shock-absorbing spring plate for collision prevention in which the spring load changes in two steps. Rapid deceleration and stop can be performed reliably even when running. In addition, the adjustment accuracy is not deviated or damaged due to a sudden impact force at the time of return, and no error occurs at the stop position due to rebound and return at the time of impact. Further, this leaf spring member has an advantage that the number of parts is single and the manufacturing cost is low.

Further, since the impact absorbing member for preventing collision can be provided in a narrow space in the scanning optical device, it is possible to reduce the size of the scanning optical device, a copier and an image reading device equipped with the scanning optical device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electrophotographic copying machine provided with a scanning optical device according to the present invention, FIG. 2 is an explanatory diagram showing moving speeds of first and second mirror units in the scanning optical device, and FIG.
FIG. 4 is a sectional view of the first and second mirror units and the shock absorbing member, FIG. 4 is a perspective view of a shock absorbing leaf spring member, and FIGS. 5A to 5D show a compression process of the shock absorbing member. FIG. 6 is a cross-sectional view, and FIG. 6 is a characteristic diagram showing the relationship between the amount of movement of the pressing member and the compression load. DESCRIPTION OF SYMBOLS 1 ... Copy machine main body 2 ... Original platen 3 ... Photoreceptor drum, 10 ... Scanning optical device 11 ... Exposure lamp, 12 ... 1st mirror 13 ... 1st mirror unit 14 ... 2nd mirror Reference numeral 15 Third mirror 16 Holder 17 Second mirror unit 18 Main lens 19 Fourth mirror 20 Housing 20A Wall 21 Shock absorbing plate Spring 21A: Mounting surface, 21B: Curved surface 21C: Tip, 22: Elastic rubber member a, A: Initial return point, l0, 1, l2: Spacing

Claims (1)

(57) [Scope of request for utility model registration] An optical system moving type scanning optical apparatus which reciprocates and scans a document surface by exposure, in order to prevent collision of the reciprocating optical system with the apparatus body during a return stroke of the optical system. Two types of cushioning members are provided at an inner surface position of the apparatus main body that abuts against the rear surface of the device main body, a shock-absorbing leaf spring member that comes into contact first and an elastic rubber member that further absorbs the pressing force of the retracted holding body. A pressure contact between the leaf spring member and the inner surface of the apparatus main body by a compressive force of only the leaf spring member, and a strong pressure contact by a composite compressive force of the leaf spring member and the elastic rubber member. A scanning optical device, wherein the scanning optical device is configured so as to change in stages and absorbs a return impact of the holder.