JPH04186245A - Filter drive mechanism for image reading device - Google Patents

Abstract

PURPOSE:To quickly and surely exchange filters and miniaturize a drive mechanism by moving the color filters from a retreat position to an insertion position by the oscillation of an oscillation arm, and returning them to the retreat position with a spring means. CONSTITUTION:A filter drive mechanism 31 includes color filters 33 of R, G, B, and M, four holding frames 35 retaining them, and four oscillating arms 37 corresponding to the frames 35. The engaging of a gear 553 of a drive gear 55 with a gear 571 of an output shaft of a stepping motor 57 and the rotation of the gear 55 by the actuation of a motor 57, causes the engaging of the gear 553 with a gear 377 of the arm 37 to oscillate the arm 37. This forwards the filters 33 to an insertion position I to be inserted in an image-formation optical path 41. The releasing of the engagement of the gears 553 and 377 causes the oscillation of the arm 37 to a retreat position Ro side with a coil spring 53 and the return of the filters 33 to the position Ro.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a filter drive mechanism used in image reading devices such as copying machines and scanners.

(Prior Art) For example, in a color copying apparatus, image information of a subject is usually divided into R (Red), G (Green), B (
A color copy is obtained by decomposing the image into each component (blue) and creating a latent image on a photoreceptor drum, and then developing these latent images in complementary colors cyan, magenta, and yellow and overlapping them. .

FIG. 23 shows an example of a general structure of a conventional color copying apparatus.

An illumination light source 12 and scanning mirrors 13 and 14 are arranged below a transparent glass plate 11 on which an original (subject) Or is placed.

The illumination light source 12 and the scanning mirror 13.14 are scanned from the position shown in the solid line to the position shown in the broken line in the figure, and the original
After being reflected by scanning mirrors 13 and 14, the illumination light reflected by
7.

In this conventional device, in order to perform color separation, a filter drive mechanism 15 placed between the scanning mirror 14 and the imaging optical system 16 sequentially switches the three color filters of R, G, and B in the optical path. Insert into. Alternatively, a filter drive mechanism is placed between the illumination light source 12 and the document Or, and the filter drive mechanism is similarly switched corresponding to the three colors of R, G, and B.

Then, by scanning the illumination light source 12 and the scanning mirrors 13 and 14 in each state, image information (latent image) separated into R, G, and B colors can be obtained on the photoreceptor drum 17 in principle.

The outer periphery of the photosensitive drum 17 is provided with charging means 18, developing means 19 corresponding to each selected wavelength (19a for yellow, 19b for magenta, 19C for cyan, and 19d for black), transfer means 20, etc. The latent images of each color formed on the photoreceptor drum 17 are developed and superimposed on the transferred material (paper) 22 sent out from the paper feeder 21, and color copies are made. can get.

By the way, in the actual device configuration, this filter drive mechanism 15 is designed to be able to quickly and reliably replace the filters of three colors (four colors), R, G, and B (and M (for monochrome) if necessary), and to install the filters. It is required that the space be small.

For example, Japanese Patent Publication No. 55-30232 proposes a structure in which these color filters are provided in a radial direction with respect to a rotating shaft and the color filters are exchanged by rotating the rotating shaft, but this rotating type requires a large installation space.

Therefore, in Japanese Patent Application No. Sho 62-136713, the present applicant provided a plurality of protrusions at intervals in the width direction and longitudinal direction of the belt, and provided a filter drive in which the belt is rotated and the color filters are sequentially moved by the protrusions. provides the mechanism.

According to this earlier application, since the color filter can be moved back and forth linearly, the filter drive mechanism can be downsized and the color filter can be replaced quickly and reliably.

(Problems to be Solved by the Invention) However, according to the above configuration, since the belt must be provided with a protrusion, there is a problem that manufacturing the belt becomes troublesome and costs are increased.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a filter drive mechanism that is small in size, can quickly and reliably replace color filters, and can further reduce costs. There is a particular thing.

(Means for Solving the Problems) In order to achieve the above object, a filter drive mechanism according to the present invention is provided corresponding to each color filter, and engages and swings on the side of each color filter, thereby driving each color filter. a swinging arm to be moved; a spring means for biasing the color filter toward a retracted position; a gear section provided on each swinging arm for swinging the swinging arm; and a gear for each swinging arm. A plurality of gear parts each mesh with the parts to swing the swing arm and move each color filter from the retracted position to the insertion position. It is characterized by being comprised of drive gears that are formed out of phase with each other.

(Function) Since a plurality of color filters can be moved back and forth linearly, the filter drive mechanism can be downsized.

In addition, the color filter is moved from the retracted position to the inserted position by the engagement of the gear part of the swing arm and the gear part of the drive gear, and is returned from the inserted position to the retracted position by the spring means.
Color filters can also be replaced quickly and reliably.

Furthermore, the swing arm and drive gear can be manufactured at low cost, and an inexpensive filter drive mechanism can be obtained.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a front view of the filter drive mechanism, and FIG. 2 is a cross-sectional side view of the same essential parts.
, M color filters 33, four holding frames 35 for holding these color filters 33, and four swing arms 37 provided corresponding to these holding frames 35.

As shown in a plan view in FIG. 3 and in a side view in FIG. An imaging optical path 41 is formed that guides the subject image reflected by the scanning mirror to the photoreceptor.

The holding frame 35 that holds each color filter 33 has a frame shape, as shown in a front view in FIG. 5, a cross-sectional plan view in FIG. 6, and a cross-sectional side view in FIG. A groove 351 for holding a color filter is formed.

A protrusion 3 with a guide hole 353 formed on the upper side of the holding frame 35
55, and a protrusion 357 is formed on one vertical side.

The holding frame 35 to which the color filter 33 is assembled is guided by a rod 43 at the upper part and a guide member 45 at the lower part, and as shown by the imaginary line in FIG.
3 is inserted into the imaging optical path 41 (A), and the retracted position (B) located outside the imaging optical path 41 as shown by the solid line in FIG. possible.

One end of the rod 43 is supported by a rail holding member 47, and the other end is supported via a side frame 49.

As shown in a side view in FIG. 8, a front view in FIG. 9, and a cross-sectional side view in FIG. ,
An insertion hole 473 into which the rod 43 is inserted is provided, and one end of each rod 43 is supported by being inserted into the insertion hole 473.

The side frame 49 is shown in the left side view in FIG.
As shown in the front view in FIG. 13 and in the right side view in FIG. It is supported by

The side frame 49 has elongated holes 49 formed above and below.
3 is attached to the end of the end surface 39A of the frame 39 via a screw inserted into the elongated hole 493, and one side of the side frame 49 engages with the tip of the swing arm 37. A stopper portion 49 that restricts falling toward the retracted position side.
5.

As shown in a plan view in FIG. 14, a front view in FIG. 15, and a side view in FIG. 16, the guide member 45 is formed with four guide grooves 451 for sliding the holding frame.
is attached to the frame 39 by press-fitting a pin 453 formed on the end surface into a hole in the end surface 39A of the frame 39.

As shown in the left side view in FIG. 17, the front view in FIG. 18, and the right side view in FIG. Long groove 371
A gear 377 having a large portion 375 is formed on the outer periphery of the boss portion 373 at the base, and one end of a coil spring 53, which will be described later, is locked in a hole 379 at the end of the gear 377.

The swinging arm 37 is rotatably supported by a shaft 381 inserted through the hole 373A of the boss portion 373, and as shown in FIG.
-1 and is supported by the support wall 39A-2.

As shown in FIG.
7 is disposed below the retracted position (b) of the color filter 33 so as to swing about a substantially central position in the moving direction of the color filter 33 as a fulcrum.

Then, with the swinging arm 37 swinging toward the retracted position (b), the color filter 33 is located outside the imaging optical path 41,
In addition, the color filter 33 faces the imaging optical path 41 with the swinging arm 37 swinging toward the insertion position (A), and the tip of the swinging arm 37 is indicated by the center line (C) in FIG. It is arranged so as to be located outside the color filter 33.

A coil spring 53 is stretched between the hole 379 of the swing arm 37 and the hook 391 on the frame 39 side, and the color filter 33 is always biased toward the retracted position (b).

The swinging of the swinging arm 37 will be explained in more detail as follows.
Swinging of the swinging arm 37 for moving the color filter 33 from the retracted position (b) to the insertion position (a) is performed via a drive gear 55 and a stepping motor 57.

As shown in FIG. 20 in a half-sectional front view, FIG. 21 in a front view, and FIG. 22 in a side view, the drive gear 55 includes a gear 551 with a large diameter and a gear with a smaller diameter than this gear 551 37
Four gears 553 meshing with the gears 7 are formed, and a hole 555 is formed in the center.

A shaft (not shown) is inserted into the hole 555 of the drive gear 55,
This shaft is supported by the end wall 39A-1 of the frame 39 and the support wall 39B-1, and the drive gear 55 is rotatably supported by the shaft.

Each of the gears 553 has a fan shape, is spaced apart in the axial direction so as to mesh with the gear 377, and is formed with phases shifted by 90 degrees from each other.

The gear 553 is meshed with a gear 571 on the output shaft of the stepping motor 57, and when the stepping motor 57 operates, the driving gear 55 rotates, and the swinging arm 37 swings due to the meshing with the gears 553 and 377. The color filters 33 are sequentially fed out to the insertion position (a), and the gear 5
When the engagement between the color filters 53 and 377 is released, the coil spring 53 causes the swinging arm 37 to swing toward the retracted position (b), and the color filter 33 is returned to the retracted position (b).

In FIG. 1, reference numeral 61 indicates a cover of the optical unit including the filter drive mechanism 31. As shown in FIG.

In this embodiment, as described above, the swing arm 37 and the drive gear 55
Since the color filter 33 is moved via the coil spring 53, the color filter 33 can be moved back and forth linearly, and therefore the filter drive mechanism 31 can be made smaller without taking up space.

Further, the drive gear 55 swings the swing arm 37 at a predetermined angle to move the color filter 33 from the retracted position (B) to the insertion position (A), and also disengages the gears 553 and 377 to move the color filter 33 to the insertion position (A). Insertion position M (by Bling 53)
Since the color filter 33 is returned from (a) to the retracted position (b), the color filter 33 can be replaced quickly and reliably.

In addition, a swing arm 37 that constitutes the filter drive mechanism 31
The drive gear 55 can be manufactured at low cost, and the filter drive mechanism 31 can be obtained at low cost.

Further, in this embodiment, a color copying apparatus has been described, but the present invention is also applicable to filter drive mechanisms of various image reading apparatuses such as scanners.

(Effects of the Invention) As is clear from the above description, the filter drive mechanism according to the present invention includes a plurality of swinging arms that move a color filter from a retracted position to an insertion position, and a plurality of swinging arms that swing these swinging arms individually. Since it is composed of a drive gear and a spring means that returns the color filter from the insertion position to the retracted position, it is small and allows for quick and reliable replacement of the color filter, and furthermore, it is possible to reduce costs. Become.

[Brief explanation of the drawing]

Fig. 1 is a front view of the filter drive mechanism, Fig. 2 is a cross-sectional side view of the essential parts, Fig. 3 is a plan view of the frame, Fig. 4 is a side view of the same, Fig. 5 is a front view of the holding frame, 6 is a plan view of the same cross section, FIG. 7 is a side view of the same cross section, FIG. 8 is a side view of the rail holding member, FIG. 9 is a front view of the same, and FIG. 1.0 is a side view of the same cross section,
Fig. 11 is a left side view of the side frame, Fig. 12 is a front view thereof, Fig. 13 is a right side view thereof, Fig. 14 is a plan view of the guide member, Fig. 15 is a front view thereof, and Fig. 16 is a plan view of the guide member. 17 is a left side view of the swing arm, FIG. 18 is a front view of the same,
Fig. 19 is a right side view of the same, Fig. 20 is a front view in half section of the drive gear, Fig. 21 is a front view of the same, Fig. 22 is a side view of the same, and Fig. 23 is a conceptual diagram of the entire color copying apparatus. be. In the figure, 31 is a filter drive mechanism, 33 is a color filter, 35 is a holding frame, 37 is a swing arm, 55 is a drive gear,
57 is a stepping motor, and 53 is a coil spring. Patent applicant Asahi Optical Co., Ltd. Agent Patent attorney No 1) Shigeru Fig. 11 Fig. 12'°\ ''' 493 \ Fig. 13 4.9 /' Fig. 20 Fig. 22 Fig. 21 551 553 5') 1 553 553

Claims (1)

[Scope of Claims] A light source that illuminates a subject; an imaging optical system that projects an image of the subject illuminated by the light source; an image reading unit that receives the image of the subject from the imaging optical system; a plurality of color filters that are movably disposed in an imaging optical path leading to an image reading section, and that separate color filters from a subject image illuminated by a light source and provide the image to the image reading section; In an image reading device, the filter drive mechanism includes a filter drive mechanism that reciprocates between an inserted insertion position and a retracted position located outside the imaging optical path, wherein the filter drive mechanism is provided corresponding to each color filter. a swinging arm that moves each color filter by engaging with each color filter and swinging; a spring means that biases the color filter toward a retracted position; and a spring means provided on each swinging arm and said swinging arm. a plurality of gear parts that mesh with the gear parts of each of the swing arms to swing the swing arms and move each color filter from the retracted position to the insertion position; 1. A filter drive mechanism for an image reading device, comprising drive gears having a predetermined circumferential length and having mutually shifted axial positions and circumferential phases.