JPH0339291B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an exposure optical system of a copying machine, and more particularly to a structure for attaching a mirror to a light-shielding box of an exposure optical system housing.

Generally, the exposure optical system of a copying machine is provided with a light-shielding box that blocks the light passing through the projection lens from external light, and this light-shielding box directs the incident light from the projection lens toward the photoreceptor (drum). A reflective mirror is installed.

In the past, since all of the frames were constructed of metal, there was a problem that, for example, there was a slight error in the distance between the barrel mounting part of the projection lens and the mounting part of the reflecting mirror, which required time and effort to adjust. The causes include dimensional errors in the metal frame or differences in mounting and fixing, and it has been impossible to adjust the frame itself. Furthermore, as a conventional mounting structure for this mirror, it is known that the mounting surface of the light-shielding box is mirror-finished and the mirror is seated on this mounting surface. It is difficult to precisely perfect the perpendicularity to the axis and the relationship between the optical axis and the photoreceptor drum. For this reason, conventionally, a spacer or the like is interposed between the mounting surface and the mirror to ensure the positional accuracy, but this adjustment work is a difficult work that requires skill and time.

Therefore, in consideration of the fact that current resin molding technology can ensure dimensional accuracy of approximately ±0.01 mm even for fairly large objects, the present invention was developed to mold an exposure optical system housing into which components of the exposure optical system of a copying machine are incorporated. A projection lens mounting portion is integrally molded into a light-shielding box that is integrally molded with this exposure optical system, and an elongated square hole through which the transmitted light of the projection lens can pass is formed in the light-shielding box, and a surface is formed in the same square hole. By integrally molding three positioning protrusions for positioning the mirror on the outer surface of the light-shielding box, it is proposed to omit the adjustment work of the mirror mounting part.

Hereinafter, details of one embodiment of the present invention will be described with reference to the drawings.

The body frame A of the electrophotographic copying machine shown in FIGS. 1 and 2 includes a pair of opposing end plates 1A,
1B and a pair of side plates 2a, 2B assembled to these end plates 1A, 1B, and are configured in a box shape with an open upper part.

In the center of the fuselage frame A, there is a second
As shown in the figure, a photosensitive drum 3 that is rotationally driven in the direction of the arrow is installed, and around this photosensitive drum 3 there are a plurality of process devices adjacent to each other in the rotational direction of the drum, namely charging electrodes 4, magnetic A brush developing device 5, a transfer paper guide plate 6, a transfer/separation electrode 7, a static elimination electrode 8, and a cleaning device 9 are arranged and positioned, and these process devices are arranged in a pair of frames 10 that can be pulled out from the body frame A as shown in the first figure. be assembled into. In addition, in FIG. 2, the symbols 11, 12, 13, 14, 1
Reference numeral 5 denotes a paper feed cassette, a paper feed roller, a conveyance roller, a fixing device, and a paper discharge roller device.

The side plates 2A and 2B have upper flanges 2a and 2b, respectively, which are bent at right angles inward of the fuselage frame A, and these upper flanges 2a and 2b are integrally molded in a deep dish shape with a resin having heat insulating properties. The exposure optical system housing B is placed thereon. Although not limited to, this exposure optical housing B includes:
First, an amount of foamed resin that is too small for the mold cavity capacity is injected into the cavity, then high pressure gas is blown into the cavity to harden the surface resin of the mold cavity, and the high pressure gas is removed to foam the internal resin. By using the molding method, it is possible to obtain a housing with precise dimensions that is lightweight, highly insulating, and free from hot water sinks.

The exposure optical system housing B has a substantially rectangular bottom wall 1.
6, and a pair of end walls 1 surrounding the bottom wall 16 on all sides.
7A, 17B and side walls 18A, 18B,
These end walls 17A, 17B and side walls 18A, 1
A large number of ventilation holes 19 are bored in 8B, and mounting screws 21 inserted into mounting holes 20 formed in the four-sided coal of the bottom wall 16 are inserted into the upper flanges 2a, 2b.
The exposure optical system housing B can be fixed to the body frame A by screwing into the screw hole 22 of the housing B. Therefore, when the exposure optical system housing B is assembled to the body frame A, the ventilation hole 19 is connected to the space C between the body housing Y and the body frame A as shown in the second diagram, so that the exposure optical system housing Convection or blow-through of the in-machine wind occurs inside B, and heating of the exposure optical system is prevented.

The bottom wall 1 of the exposure optical system housing B
A projection lens mounting seat 23 is integrally molded in the center of the bottom wall 16, and a projection lens 24 is mounted on the projection lens mounting seat 23 using a U”-shaped band 25. A light-shielding box 26 that rises upward is integrally molded in the portion .In other words, the light-shielding box 26 with its bottom open, which is a feature of the present invention, is as shown in FIGS. 3 and 4. A front wall 26a, a rear wall 26b, and a pair of opposing side walls 2 rise upward from the bottom wall 16 and are assembled into a frame.
6c and 26d, and above these is a ceiling wall 26e.
It is covered by At the center of the front wall 26a is a circular hole 27 through which light from the projection lens 24 enters.
The reflective surface of the mirror 28 is connected to the light-shielding box 2 on the inclined rear wall 26b facing the circular hole 27.
A rectangular hole 29 elongated in the width direction is bored to expose the inside of the case 6.

On the other hand, the rear wall 26 to which the mirror 28 is attached
On the outer surface of b, three protrusions 30A, 30B, 30C located on both sides of the square hole 29 in the width direction are provided on the rear wall 2.
6b, the mirror 28 is seated on the tips of these protrusions 30A, 30B, 30C, and then fixed to the rear wall 26b using the fasteners 31A, 31B and fixing screws 32. A pair of guide claws 33A and 33B are integrally formed with the bottom wall 16 directly below the side walls 26C and 26d of the side wall 26 of the light shielding box 26, and between these guide claws 33A and 33B, the lower part of the light shielding box 26 is guided. A covering light shielding plate 34 is supported so as to be freely removable. This shielding plate 34 has a slot 35 through which the light reflected from the mirror 28 can pass through, so that the light from the projection lens 24 passes through the mirror 28 and the slot 35 and forms an image on the circumferential surface of the photoreceptor drum 3. will be done.

Returning to FIGS. 1 and 2, on the upper surfaces of both side walls 18A and 18B of the exposure optical system housing B, both ends of a first movable base 39 to which an illumination lamp 36, a mirror 37, and a slit plate 38 are attached are placed. On the guide rail surfaces 41 of the side walls 18A and 18B, which are formed into guide rail surfaces 40A and 40B, and which are located internally and lower than these guide rail surfaces 40A and 40B, two mirrors 42 and 43 having a right angle are provided. Both ends of the second movable base 44 having a second movable base 44 are guided and supported. Of course, the end of the first movable base 39 and the second movable base 44
A wire (not shown) is stretched between the floating pulley 45 at the end of the frame, the fixed pulleys 46 and 47 at both ends of the side walls 18A and 18B, and the relay pulley 48 at the middle of the side wall 18A. 1 movable stand 3
9 is at a constant speed, and the second movable base 44 is at a constant speed.
It will be moved at 1/2 the speed of the movable table 39.

On the other hand, both side walls 1 of the exposure optical system housing B
Three posts 49A, 49B, 49C and 50A, 50B, 5 stand up above both side walls 18A, 18B at both ends and middle part of 8A, 18B.
0C is integrally molded. These posts have horizontal upper surfaces or seating surfaces 51, and between these seating surfaces are a pair of glass mounting plates 52A, 52 located upward in a direction parallel to the guide rail surfaces 40A, 40B.
B is fixed with screws 53, and an original table glass D is fixedly mounted between these glass mounting plates 52A and 52B so as to cover the upper part of the exposure optical system housing B.

As described above, if the projection lens mounting seat 23 and the rear wall 26b of the mirror mounting surface are molded accurately, the projection lens and mirror can be mounted and fixed with almost no adjustment. Light-shielding box 2 precision molded into the exposure optical system housing B of
Three seating protrusions 30A, 30 on the mirror mounting surface of 6
B, 30C are projected, and these seating protrusions 30
Since the mirror 28 is seated on A, 30B, 30C, the seating protrusions 30A, 30B, 30 relative to the optical axis
As long as the position C is precisely formed, the mirror 28 that requires adjustment can be attached. and,
Light shielding shaft 26 and seating projections 30A, 30 of the present invention
Since B and 30C need only be molded into the exposure optical system housing B made of resin, an inexpensive structure that is effective for mass production can be achieved.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of the body of an electrophotographic copying machine to which the present invention has been applied, Fig. 2 is a side sectional view of the copying machine, and Fig. 3 is an exploded perspective view of the mirror mounting portion of the copying machine. FIG. 4 is a sectional view taken along the - line in FIG. 3. B...Exposure optical system housing, 16...Bottom wall,
26...Shading box, 28...Mirror, 30A, 30
B, 30C...Seating projection.

Claims (1)

[Claims] 1. The exposure optical system housing in which the components of the exposure optical system of the copying machine are incorporated is molded with resin, and the projection lens mounting part is integrally molded into the light-shielding box that is integrally molded with this exposure optical system, and the transmission of the projection lens is forming an elongated square hole in the light-shielding box through which light can pass;
A mirror mounting structure characterized in that three positioning protrusions for positioning the mirror are integrally molded on the outer surface of the light shielding box facing the same square hole.