JPH0413692B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has a housing that houses an illumination means, and images an original image of a copy document on a platen through an imaging means provided at the bottom of the housing. In a variable magnification type copying machine that projects images onto a predetermined photosensitive surface at an arbitrary copying magnification, the present invention relates to an improvement in a light shielding device provided for blocking light leaking onto the photosensitive surface from the operating section of the image forming means. .

[Conventional technology]

As a conventional variable magnification copying machine, there is one shown in FIG. 5, for example. this is,
A housing 1 having a closed cross-section structure having a movable bottom 1a that can be moved up and down is formed, and a rectangular opening 2 is provided at the top of the housing 1, and a copy document 3 is placed in the opening 2 made of glass or the like. The platen 4 is mounted on one side of the periphery of the housing 1, and a flash light source 5, a lampshade 6 that blocks direct light from the flash light source 5 toward the platen 4, and a lamp shade 6 extending substantially directly below from the flash light source 5. In addition to installing blockers 7 to block light, a highly reflective surface 8 coated with a white diffusing material is formed on the inner wall surface of the housing 1, and a platen 4 is provided approximately in the center of the movable bottom portion 1a. Opening a long hole-shaped operation slit 9 extending diagonally,
An imaging means 10 consisting of an imaging lens 10a and a lens case 10b is slidably mounted on the operating slit 9. Note that the movable bottom portion 1a and the imaging means 10 are driven by a drive mechanism not shown. When the flash light source 5 emits light during copying, the light from the flash light source 5 is irradiated into the housing 1 through the gap between the lampshade 6 and the blocker 7, and is subjected to multiple reflections within the housing 1 via the high reflection surface 8. After that, the light reaches each part of the platen 4 with substantially the same optical path length, and illuminates the entire surface of the copy document 3 on the platen 4 with substantially uniform illuminance. Thereafter, the illuminated original image of the copy document 3 is projected onto a predetermined photosensitive surface 13 with substantially uniform illuminance via an imaging means 10 and a light amount correction filter 12 that corrects variations in light amount when passing through the imaging means 10. , the copy image quality based on the projected image on the photosensitive surface 13 is maintained at a good level.

As shown in FIGS. 5 and 6, such a variable magnification type copying machine has a movable bottom portion 1a set at the center position between the platen 4 and the photosensitive surface 13 at the same magnification, and a movable bottom portion 1a located at the center position of the operating slit 9. By setting the imaging means 10 at the position, the copy original 3 on the platen 4 is
Project the original image as it is onto the photosensitive surface 13, and
At the time of reduction, the movable bottom 1a is set at a position elevated from the position at the same magnification, and an image is formed at one end in the longitudinal direction of the operating slit 9 located near one corner of the platen 4, which serves as the reference point _R0 for positioning the copy original 3. By setting the means 10, the original image of the copy document 3 on the platen 4 is reduced and projected onto the photosensitive surface 13 as shown by the dashed line in FIG. By setting the image forming means 10 at a position lower than the normal position and at the other end in the longitudinal direction of the operating slit 9, the original of the copy document 3 on the platen 4 is set as shown by the two-dot chain line in FIG. The image is enlarged and projected onto the photosensitive surface 13.

Incidentally, in such a variable magnification type copying machine, since a gap C is formed between the operating slit 9 and the image forming means 10, the irradiation light from the flash light source 5 and the copy original 3 A part of the original illumination light from the source leaks out of the housing 1 through the gap C and reaches the photosensitive surface 13 located below the housing 1.
As a result, the illuminance distribution of the projected image on the photosensitive surface 13 becomes non-uniform, and there is a risk that the quality of the copied image will be impaired accordingly. In order to eliminate this situation, the gap C between the operating slit 9 and the imaging means 10 must be
It is necessary to block the housing 1 from leaking light. As a conventional light shielding device that meets such demands, for example, as shown in FIGS. 7a and 7b, a lens case 1 of the image forming means 10 is
Attach a plate-shaped light shielding member 15 to the periphery of the plate 1
6, the light shielding member 15 is brought into sliding contact with the lower surface of the movable bottom portion 1a, and the light shielding member 15 closes the gap C between the operating slit 9 and the imaging means.

[Problem that the invention seeks to solve]

However, in such a conventional light shielding device, the longitudinal dimension of the operating slit 9 is L, the outer diameter of the imaging means 10 is K, and the imaging means 10 is set at the same magnification position as shown in FIG. 7a. When the light shielding member 15 is moved from the position shown in FIG. 7b to the reduction position (or enlargement position) shown in FIG.
It will move by (δ=(L-K)/2).
In this case, in order to always close the gap C with the single light shielding member 15, the length L' of the light shielding member 15 along the longitudinal direction of the operating slit 9 must be set such that L'>L+
Must be set to 2δ=2L−K. At this time, the length L' of the light shielding member 15 is nearly twice the longitudinal dimension L of the operating slit 9, which not only inevitably increases the size of the light shielding device itself, but also increases the size of the light shielding device. As the size increases, a larger installation space for the light shielding device must be secured within the housing 1, and the housing 1 itself also becomes larger, creating a problem in that it does not meet the demand for lighter weight copying machines.

[Means and actions for solving problems]

This invention has been made in view of the above-mentioned problems, and its object is to reliably prevent leakage of light from the image forming means operating section in the housing, while also making the housing compact and compact. An object of the present invention is to provide a light shielding device for a variable magnification type copying machine that can be downsized. and,
In order to achieve this object, the present invention provides a variable magnification type copying machine in which an imaging means is slidably attached to an elongated operating slit provided in a movable bottom of a housing. A driving light shielding member that moves integrally with the image forming means is provided on the periphery of the image forming means, and a driven light shielding member is slidably interposed between the driving light shielding member and the movable bottom, and the moving light shielding member The slit into which the image forming means is slidably and loosely fitted is formed to be shorter than the longitudinal dimension of the operating slit, and the gap between the image forming means and the operating slit is closed by the driving light blocking member and the driven light blocking member. This is how it was done.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

In the embodiments shown in FIGS. 1 to 3, a light blocking device is shown which is applied to the variable magnification type copying machine shown in FIG.
a driven light shielding member 30 that is slidably interposed between the drive light shielding member 20 and the lower surface of the movable bottom portion 1a of the housing 1;
It is made up of.

In this embodiment, the movable bottom portion 1a of the housing 1 is fixed to a carriage 40 that moves up and down via a stopper 41, and the imaging means 10 is controlled by a drive mechanism (not shown) to move the movable bottom portion 1a. It is designed to be able to move appropriately along the slit 9.

In this embodiment, the driving light shielding member 20
is formed of a plate-like member that can sufficiently cover a slit 31 of a driven light shielding member 30, which will be described later, and has a length L that is shorter than the driven light shielding member 30 along the longitudinal direction of the operating slit 9. Has ₁ . An insertion hole 21 that fits into the lens case 10b of the imaging means 10 is formed in the center of the driving light shielding member 20, and a flat guide protrusion 22 is integrally formed on one side in the width direction. At the same time, a guide leg piece 23 whose tip is bent downward is integrally provided on the other side. Furthermore, the driving light shielding member 20 is configured to include the insertion hole 2
1 to the periphery of the imaging means 10, and the mounting plate 24 and the stopper 25 to the imaging means 10.
It is attached to the image forming means 10 and moves integrally with the image forming means 10. In addition, the guide protrusion 22
is slidably placed on a support piece 42 provided on one side of the carriage 40 in the width direction, and the guide leg piece 23 is slidably placed in a guide groove 43 provided on the other side of the carriage 40 in the width direction. They are movably fitted, and the drive light shielding member 20 can maintain a posture parallel to the general plane of the movable bottom portion 1a during movement.

Further, the driven light shielding member 30 is formed of a plate-like member that can sufficiently cover the operating slit 9, and a slit 31 is provided in the center thereof along the longitudinal direction of the operating slit 9. 31 has a width dimension equal to that of the operating slit 9 and a length dimension M shorter than the longitudinal dimension L of the operating slit 9. The driven light shielding member 30 is restrained and held in its width direction by a pair of guide protrusions 32 provided on the lower surface of the movable bottom portion 1a.
The image forming means 10 is slidably fitted into the slit 31, while being movable along the longitudinal direction of the operating slit 9.

Furthermore, in this embodiment, the length L ₁ of the driving light shielding member 20 is equal to the longitudinal dimension M of the slit 31 in the driven light shielding member 20, the longitudinal dimension M of the slit 31, and the insertion hole in the driving light shielding member 20. 21 (corresponding to the outer diameter dimension K of the imaging means ₂₀ ). It is set to be slightly larger than the sum of the longitudinal dimension L of the operating slit 9 and the longitudinal dimension difference (LM) between the operating slit 9 and the slit 31.

In FIGS. 1 to 3, 51 and 52 are mounting holes for fixing the drive light shielding member 20 to the mounting plate 24, and 53 is a drive light shielding hole for the head of the stopper 25 for mounting the drive light shielding member 20. The recessed portion 54 for embedding the member 20 from the upper surface is a boss integrally formed on the carriage 40 for fixing the movable bottom portion 1a.

Next, the operation of the light shielding device according to this embodiment will be explained.

Now, at the same magnification, as shown in FIG. Placed. At this time, assuming that the driven light shielding member 30 is arranged approximately symmetrically with respect to the center of the operating slit 9, the driven light shielding member 30 is in sliding contact with the periphery of the operating slit 9 on the lower surface of the movable bottom portion 1a, and The driving light shielding member 20 is connected to the slit 3 of the driven light shielding member 30.
Since the gap C' between the operating slit 9 and the image forming means 10 is closed, the gap C between the operating slit 9 and the image forming means 10 is reliably closed. Therefore, light from inside the housing 1 does not leak to the photosensitive surface 13 side through the gap C.

Further, during reduction or enlargement, the imaging means 10 moves from the center of the operating slit 9 toward one end of the operating slit 9, as shown in FIGS. 4b and 4c. At this time, the driving light shielding member 20 immediately moves integrally with the imaging means 10, but the driven light shielding member 30 moves as the imaging means 10 slides within the slit 31, as shown in FIG. 4b. As shown in FIG. 4c, after the imaging means 10 collides with one end of the slit 31, the imaging means 10 and move together. Then, when the image forming means 10 reaches the reduction position or the enlargement position, both the light shielding members 20 and 30 stop. In this state, both light shielding members 20 and 30 maintain a state in which the gap C between the operating slit 9 and the imaging means 10 is closed, considering their dimensional relationship.

Furthermore, in this embodiment, the length of the light shielding device corresponds to the length _L2 ( _L2 >2L-M) of the driven light shielding member 30, as shown in FIG. On the other hand, in the conventional type shown in Figure 7a, the length dimension of the light shielding device is L'(L'>2L
-K). At this time, since the longitudinal dimension M of the slit 31 is larger than the outer diameter dimension K of the imaging means 10, the length dimension of the light shielding device is smaller than that of the conventional one, and the device itself can be made smaller accordingly. becomes possible. Further, as shown in FIGS. 2 and 4, the driving light shielding member 20 moves from the same magnification position to (δ ₁ )(δ ₁ =(L−
Although the driven light shielding member 30 moves integrally with the imaging means 10 by K)/2), the driven light shielding member 30 moves from the same magnification position to (δ ₂ )(δ ₂ =(LM)/2<
δ ₁ ). In this case, the installation space S of the light shielding device in the housing 1 is
The length dimensions L ₁ and L ₂ of the respective light shielding members 20 and 30,
Movement distance of each light shielding member 20, 30 (2δ ₁ ) (2δ ₂ )
The value is set to the larger of the sums of . Now, if the value on the driven light shielding member 30 side becomes larger than that on the driving light shielding member 20, the setting space S of the light shielding device is S=L ₂
It is set within a range that satisfies the conditional expression +2δ ₂ >3L−2M. On the other hand, in the conventional type shown in FIG. 7a, the length L' of the light shielding member 15 is 2L.
- larger than K, and the movement distance (2δ) of the light shielding member is L-
Since it is K, the installation space for the shading device is
S' is set only within a range that satisfies the conditional expression S'=L'+2δ>3L-2K. At this time, since the longitudinal dimension M of the slit 31 is larger than the outer diameter dimension K of the imaging means 10, the installation space S of the light shielding device according to this embodiment is smaller than that of the conventional one. Accordingly, it is also possible to downsize the housing 1 itself. In addition, when the installation space S of the light shielding device is set by the value on the driving light shielding member 20 side, the above installation space S
is set within a range that satisfies the conditional expression S=L ₁ +2δ ₁ >2M−2K, but since the longitudinal dimension M of the slit 31 is smaller than the longitudinal dimension L of the operating slit 9, this Even in this case, the installation space S for the light shielding device is smaller than that of the conventional one.

In addition, in the above embodiment, the driven light shielding member 30
Although it is made up of one piece, it is not necessarily limited to this, and a plurality of members may be made to overlap each other. Furthermore, in the above embodiment,
Although a light blocking device is provided on the lower surface side of the movable bottom portion 1a, a light blocking device may be provided on the upper surface side of the movable bottom portion 1a. Furthermore, the specific configurations, support means, etc. of the driving light shielding member 20 and the driven light shielding member 30 are not limited to those shown in the above embodiments, and may be modified as appropriate. Furthermore, in the above embodiment, the entire bottom portion of the housing 1 is configured as the movable bottom portion 1a, but a portion of the bottom portion of the housing 1 may be configured as the movable bottom portion 1a. Furthermore, the various members constituting the variable magnification type copying machine are not limited to those shown in the above embodiments, and may be modified in design as appropriate.

〔Effect of the invention〕

As described above, according to the light shielding device for a variable magnification type copying machine according to the present invention, a plurality of light shielding members are overlapped so as to be relatively movable, and the gap between the image forming means and the operating slit is closed by the plurality of light shielding members. Since the light shielding device is divided into blocks, it is not only possible to reliably prevent light from leaking from the operating section of the imaging means, but also to reduce the length of the light shielding device along the longitudinal direction of the operating slit. Accordingly, the light shielding device itself can be made more compact, and as the light shielding device is made smaller, the installation space for the light shielding device within the housing can be reduced, and the housing can be made more compact.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a light shielding device in a variable magnification type copying machine according to the present invention;
The figure is an installation sectional view corresponding to the - line in Fig. 1, and Fig. 3 is an installation sectional view corresponding to the - line in Fig. 1.
Fig. 4a is a cross-sectional explanatory diagram corresponding to Fig. 2 showing the state of the light shielding device at the same magnification, and Fig. 4b and c are cross sections similar to Fig. 4a showing the operating process of the light shielding device at the time of reduction. 5 is a perspective view showing an example of a conventional variable magnification type copying machine, FIG. 6 is an explanatory view showing its operation, and FIGS. 7a and 7b are examples of a conventional light shielding device, respectively. FIG. 4 is a cross-sectional explanatory diagram showing a state at the time of doubling and a state at the time of reduction. [Explanation of symbols] 1... Housing, 1a... Movable bottom, 2... Opening, 3... Copy original, 4... Platen, 5... Flash light source (illumination means), 6
... Lampshade (illumination means), 7 ... Brodka (illumination means), 8 ... Highly reflective surface (illumination means), 9
...Operation slit, 10...Imaging means, 13...
Photosensitive surface, 20...driving light shielding member, 30...driven light shielding member, 31...slit.

Claims (1)

[Claims] 1. A housing with a closed cross-sectional structure having a movable bottom that can be moved up and down, a platen that is attached to an opening formed at the top of the housing and forms a placement surface for a copy original and is made of a transparent member, and the housing an illumination means disposed inside the housing to illuminate the platen; and an imaging means slidably mounted along an elongated operating slit formed in the movable bottom of the housing, the movable bottom and by moving the imaging means to an appropriate position, the original image of the copy document on the platen illuminated by the illumination means is projected onto a predetermined photosensitive surface at an arbitrary copying magnification via the imaging means. In the variable magnification type copying machine, a driving light shielding member is provided at the periphery of the imaging means and moves integrally with the imaging means, and a driving light shielding member is slidably interposed between the driving light shielding member and the movable bottom part. and a driven light shielding member having a slit which is shorter than the longitudinal dimension of the operating slit and into which the imaging means is slidably and loosely fitted, the driving light shielding member and the driven light shielding member. A light shielding device for a variable magnification type copying machine, characterized in that: a gap between the image forming means and the operating slit is closed.