JPH0766153B2 - Optical system moving frame in optical system movable exposure apparatus - Google Patents

Description

The present invention relates to an improvement of an optical system moving frame of an optical system moving type exposure apparatus in an image forming apparatus such as an electrostatographic copying machine or a printer.

[Conventional technology]

As the optical system moving frame in the above-mentioned optical system moving exposure apparatus, the applicant of the present invention is unlikely to cause torsional vibration or vertical movement due to an external excitation force that adversely affects image formation, and saves Japanese Patent Application Laid-Open No. 1-116664 proposes a moving frame for an optical system that can achieve space and weight reduction.

This optical system moving frame is constructed by arranging reinforcing ribs in a truss shape on the inner surface of the frame, which has a rectangular shape in a plan view. The space saving is achieved by using the truss-shaped reinforcing ribs on the inner surface of the rectangular frame, and the torsional natural frequency of the optical system moving frame is significantly increased. It is difficult for torsional vibration and vertical movement due to

[Problems to be Solved by the Invention]

However, there is room for improvement in casting the above-mentioned optical system moving frame body for the purpose of mass production because it has the following problems.

That is, there is a problem that the flow of molten aluminum to the reinforcing ribs connected in a truss shape is poor, a nest is generated in the reinforcing ribs, and a chip due to insufficient filling of molten aluminum occurs.

The present invention has been made in view of such circumstances, and by arranging reinforcing ribs in a truss shape, mass production while maintaining the advantage of prior art that torsional vibration and vertical movement are less likely to occur The purpose is to solve the above problems at the time.

[Means for Solving the Problems]

The optical system moving frame body according to the present invention, which has achieved the above object, is a casting molded product in which reinforcing ribs are arranged in a truss shape on the inner surface of the frame body having a rectangular plan view, and the frame body It is characterized in that a thin surface member connected to the frame and the reinforcing rib is provided in a space surrounded by the reinforcing rib.

[Action]

According to the above characteristic configuration, the filling of the casting material into the space portion of the reinforcing rib is performed through the space portion of the surface member in addition to the space portion of the frame body.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an electrostatic photocopier as an example of an image forming apparatus.
In the figure, reference numeral 1 is a main body of a copying machine, a contact glass 2 and a document holder 3 are provided on an upper portion thereof, and a photoconductor 4 and a charging section 5, a developing section 6 and a transfer section 7 arranged around the photoconductor 4 are provided inside thereof. , A copy paper separating unit 8, a cleaning unit 9, and the like, and an optical system moving type exposure device 10 is provided in the lower space of the contact glass 2. Further, a paper feeding and conveying device 11, a paper ejection and conveying device 12, Fixing device 13, paper ejection roller pair 14, paper feed cassette
It is equipped with a paper ejection tray 16 and the like.

As shown in FIG. 3, the exposure apparatus 10 of the optical system moving type has a light source 17 for projecting a document surface, a reflector 18, and a first mirror 19 for projecting reflected light from the document surface in the direction of arrow P.
And a second optical system moving frame body including a first optical system moving frame body 20 and a second and third mirrors 21 and 22 for reflecting light from the first mirror 19 and projecting the light in the direction Q. 23 is provided so as to be capable of reciprocating in the directions of arrows P and Q, a lens device 24 that collects the reflected light from the third mirror 22, and a lens device 24 that reflects the light passing through the lens device 24 toward the photoconductor 4. 4 mirrors 25 are provided.

In FIG. 3, 26 is a support rod for supporting one end side of the first and second optical system moving frame bodies 20, 23, and 27 is the other end side of the first and second optical system moving frame bodies 20, 23. Is a support member for supporting the.

Further, 28 is an arrow mark for the first and second optical system moving frame bodies 20, 23.
An optical system driving device for reciprocating in the P and Q directions. Two path inflection rotating bodies 29, 30 are provided at positions outside the reciprocating range of the first and second optical system moving frame bodies 20, 23. And a rotary body 31 and an intermediate rotary body 32 that are connected to a motor (not shown).
While the second optical system moving frame 23 is provided with
I have attached 33.

Then, one end of the transmission wire 34 is fixed to the fixed portion 35 on the copying machine main body 1 side, and the transmission wire 34 is attached to the idle rotation body 33, one path inflection rotation body 29, and the intermediate rotation body 32.
Then, the rotary body 31 and the other path inflection rotary body 30 are sequentially wound, and the transmission wire 34 is attached to the first optical system moving frame body 20 via the fastening body 36, and the transmission is performed. The wire 34 is wound around the free-rotating body 33 again, and its end is fixed to another fixing portion 37 on the copying machine main body 1 side.

Thus, with the forward and reverse rotation of the motor (not shown), the optical path length from the light source 17 to the lens device 24 is always constant,
The first optical system moving frame body 20 is replaced with the second optical system moving frame body 23
It is configured to reciprocate in the same direction at double speed.

FIG. 1 schematically shows a configuration example of the first optical system moving frame body 20, one end of which is supported by the support rod 26 at two points via two bearings 38 and 39, and Although not shown, the other end side is supported at one point by the support member 27 (see FIG. 3) via the block support 40.

Next, a specific structure of the first optical system moving frame body 20 will be described with reference to FIGS. 1 and 4 and 5. The first optical system moving frame body 20 includes a pair of long side members which are parallel to each other. A frame body 20A having a rectangular planar shape including a short side member 20b extending from an end portion of the frame 20a, a reinforcing rib 20B having a T-shaped truss-shaped cross section continuous to the inner surface of the frame body 20A, and the frame body 20A. And reinforcement ribs
A thin surface member 20C located in a triangular space surrounded by 20B and connected to the frame member 20A and the upper surface member a of the reinforcing rib 20B, and a rib member 20D provided as necessary. .

The first optical system moving frame body 20 has the long side member 20.
The side portion of a, more specifically, as shown by the phantom line b in FIG. 4, the portion where the two reinforcing ribs 20B intersect and which corresponds to the apex of the triangle and faces the surface member 20C is set to the gate position. Although it is cast from aluminum, which has high rigidity for its lightweight, it can be cast from other materials such as BMC resin and glass-filled resin.

According to the above configuration, since the reinforcing rib 20B is T-shaped, the strength is increased, and the flat upper surface member a of the reinforcing rib 20B is used to attach the first mirror 19 and the like. Can be performed stably.

Moreover, since the surface member 20C is provided on the upper side, the natural frequency of the optical system moving frame body 20 becomes high, and
Although there is an advantage that the torsional vibration and vertical movement of the optical system moving frame body 20 caused by the external excitation force are effectively prevented,
As shown in the figure, the face member 20C may be arranged continuously on the lower side of the reinforcing rib 20B.

7 (A) to 7 (C) show another embodiment of the optical system moving frame body 20, and in each case, the reinforcing rib 20B is constituted only by the vertical member c.

And in FIG. 7 (A), the surface member 20C is continuously provided on the lower side of the reinforcing rib 20B, but in FIG. 7 (B), the surface member 20C is provided continuously to the upper end of the reinforcing rib 20B. In FIG. 6C, the surface member 20C is continuously provided on the upper side of the reinforcing rib 20B so as to increase the natural frequency of the optical system moving frame 20.

However, in the configuration shown in FIG. 7B, the optical system moving frame 20
Since it becomes difficult to make the gate face the surface member 20C during the casting molding, it is preferable to take the configuration shown in FIGS. 7A and 7C from the viewpoint of the casting molding.

The cross-sectional shape of the reinforcing rib 20B and the disposition position of the surface member 20C are not limited to those of the various embodiments described above.

Further, it goes without saying that the present invention can be applied to the second optical system moving frame 23.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention provides an optical system moving frame body formed by casting reinforcing ribs in a truss shape on the inner surface of a frame having a rectangular shape in a plan view, in a space surrounded by the frame body and the reinforcing ribs. By providing a thin surface member that is continuous with the frame and the reinforcing rib in the portion, the filling of the casting material into the space of the reinforcing rib is performed through the space of the surface member in addition to the space of the frame. And then,
The flow of the casting material into the space portion of the reinforcing rib is improved, and the insufficient filling of the casting material into the space portion of the reinforcing rib and the generation of cavities are effectively prevented, and the addition of the surface member makes it possible to resist twisting. Upsizing can be expected, and as a result, a high-performance optical system moving frame can be obtained.

Moreover, since the surface member is thin, the weight of the surface member does not increase so much, and as a whole, the object of the present invention can be achieved by a simple improved technique of adding a thin surface member. is there.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a moving frame of an optical system, FIG. 2 is a schematic vertical sectional side view of an electrostatic photocopier as an example of an image forming apparatus, and FIG.
FIG. 4 is a perspective view showing an exposure apparatus and a driving apparatus therefor.
FIG. 5 is a partially cutaway perspective view of the optical system moving frame, and FIG. 5 is a partial sectional view of the optical system moving frame in the longitudinal direction. FIGS. 6 and 7A to 7C are partial cross-sectional views showing another embodiment of the optical system moving frame body. 10: Optical system movable exposure device, 20: Optical system moving frame,
20A: Frame body, 20B: Reinforcing rib, 20C: Face member.

Claims (1)

[Claims] 1. An optical system movable frame in an optical system movable exposure apparatus, comprising a cast molded product in which reinforcing ribs are arranged in a truss shape on the inner surface of the frame having a rectangular shape in plan view, and In the space surrounded by the frame and the reinforcing ribs,
An optical system moving frame body in an optical system moving type exposure apparatus, characterized in that a thin surface member connected to the frame body and the reinforcing rib is provided.