JPS6325348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure apparatus for an electronic copying machine, and more particularly to a slit type exposure apparatus for an electronic copying machine having a variable magnification function.

In an electronic copying machine having a variable magnification function, the width of an image formed on the surface of a photoreceptor during variable magnification copying is different from the width of the original document.

For example, during reduction copying, the width of the image becomes smaller compared to the original width according to the reduction ratio, but the area outside the image area on the surface of the photoreceptor is usually fully charged and developed, so it becomes solid black ( The toner adheres uniformly) and becomes brittle.

For this reason, when copy paper of a size corresponding to the reduction ratio is supplied and copied, the solid black area is not transferred to the copy paper and all flows to the cleaner section.
This places a considerable burden on the cleaner section and shortens its lifespan.The toner box in the cleaner section (the box for collecting collected toner) fills up quickly and must be replaced within a short period of time.It promotes dirt inside the copier. This has various problems, such as increased consumption of developer material (toner).

Therefore, various means have been proposed to eliminate static electricity by irradiating unnecessary parts other than the image area on the surface of the photoreceptor with light during variable-magnification copying, and to create an emergency state.

For example, as described in U.S. Pat. No. 4,047,811, the lens is switched to adjust the optical path length during variable magnification copying, and as a result, an exposure lamp that is unnecessary for image formation is placed on an unnecessary portion of the photoreceptor surface. A structure is known in which light is used to irradiate the object before it passes around the lens barrel to remove static electricity and bring it into an uncharged state.

This structure has advantages such as being able to use the light from the exposure lamp and eliminating the need for other light sources, but on the other hand, the structure becomes very complex because lens switching and reflective members must be controlled in conjunction with each other. There is a problem if the product is damaged.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to eliminate static electricity from the outside of the image area on the surface of the photoreceptor using light from an exposure light source during variable-magnification copying, and to make the structure non-charged. An object of the present invention is to provide a simple exposure device for an electronic copying machine.

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

The first mirror 1 has a roller 3 in sliding contact with a guide plate 2 and a leg 5 that is slidable along a guide rod 4, and is fixed to a first carriage 7 that can reciprocate along a platen glass 6. Further, the first carriage 7 is provided with an exposure light source A.

The second mirror 8 is provided with a roller 9 in sliding contact with the guide plate 2 and is fixed to a second carriage 10 which is slidable along the guide rod 4.

11 is a lens assembly, and a guide rail 12
It has a structure in which a lens 11b is incorporated into a holder 11a which serves as a movable light shielding body and is provided to be reciprocally movable along the exposure light source A. The lens 11b moves along the optical path of the light reflected from the original by the exposure light source A to change the magnification.

B is a fixed light shielding body provided on the incident side of the optical path of the lens assembly 11, and has a shape in which a hole b is bored in a plate material. C is the lens assembly 11
This is a photoreceptor provided on the exit side of the optical path.

The lens assembly 11 and the fixed light shielding body B have a positional relationship as shown in FIG.

That is, when the lens assembly 11 is at the original size position (broken line position), the light in the optical path is irradiated onto the entire surface A of the photoreceptor surface C' through the lens 11b, and an image is formed on the entire surface, and when the lens assembly 11 is at the reduced position (solid line position). position), the light in the optical path is irradiated only on the central part B of the photoreceptor surface C' through the lens 11b, and an image is formed only in the central part (that is, the central part B becomes the image area). A part of the light is irradiated from the light passage gap formed between the fixed light shielding body B and the movable light shielding body 11a to both ends C and C of the central part B on the photoconductor surface C' (that is, the part outside the image area , C).

Because of this structure, when the lens 11b is at the original size position (during 1-size copying), the image of the original is formed on the entire surface of the photoreceptor surface C', resulting in a 1-size copy.

Furthermore, when the lens 11b is at the reduction position (during variable magnification copying), the image of the original is formed in a reduced form on the center part B on the surface C' of the photoreceptor, resulting in a reduced copy, and the light from the exposure light source A is The portions C and C outside the image area on the surface C' of the photoreceptor are irradiated with electricity and become uncharged.

Therefore, the areas outside the image area C and C do not become solid black, reducing the burden on the cleaning member and extending its life. It also lengthens the replacement cycle of the cleaning member's toner box and reduces dirt inside the copying machine. It is possible to reduce the amount of developer material consumed.

It has the following advantages.

Further, since only the fixed light shielding body B and the movable light shielding body 11a are provided, the configuration is simple.

In the above embodiments, the case where positioning is performed at the center (center registration) during variable-magnification copying has been explained, but when positioning is performed at the corner (corner registration) during variable-magnification copying, the situation is as shown in FIG.

That is, during variable magnification copying, the lens assembly 11 moves toward one end and approaches the photoreceptor, creating a gap for light to pass between the fixed light shield B and the one end of the movable light shield 11a, and the photoreceptor. One end portion C of the body surface C' is irradiated with light from the exposure light source A to eliminate static electricity.

Next, in FIG. 1, mirrors 1 and 8 and lens assembly 1
The structure for moving 1 and 1 will be explained.

Reference numerals 13 and 14 indicate first and second fixed pulleys provided on both sides of the first and second mirrors 1 and 8 in the moving direction, and a drive pulley 15 is provided at an intermediate position between the first and second fixed pulleys 13 and 14. A capstan (capstan) is provided, and the drive pulley 15 is transmitted to a main drive source 17 such as a motor via a clutch 16, and a first cable 18 is wound around the drive pulley 15.

One end of the first cable 18 is connected to the first fixed pulley 1
3 to the first carriage 7, and then wound around a movable pulley 19 provided on the second carriage 10, and then connected to one longitudinal end of the movable body 21 via the first auxiliary fixed pulley 20.

On the other hand, the other end of the first cable 18 passes through the second fixed pulley 14 and is wound around the movable pulley 19, and then passes through the second auxiliary fixed pulley 22 to the movable body 21.
It is connected to the other end in the longitudinal direction.

23 is a second cable, one end of which is fixed to one end of the movable body 21, and the other end connected to the third auxiliary fixed pulley 24 and the small diameter portion 25 of the first two-stage pulley 25.
a, large diameter part 25b, lens 11, large diameter part 26b and small diameter part 26b of the second two-stage pulley 26, connected to the other end of the movable body 21 via the fourth, fifth, and fifth auxiliary fixed pulleys 28, 29; It has been done.

The movable body 21 is supported so as to be movable in the longitudinal direction and has longitudinal rack teeth 30 cut therein, and a lens drive motor 31 is mounted on the rack teeth 30.
A pinion 33 fixedly attached to an output shaft 32 is engaged with the output shaft 32.

The first and second two-stage pulleys 25, 26 have the same dimensions, the diameters of the small diameter portions 25a, 26a are d〓, and the diameters of the large diameter portions 25b, 26b are D〓.

Next, its operation will be explained.

When the main drive source 17 is driven with the clutch 16 in contact, the drive pulley 15 rotates and the first cable 18
is moved in the direction of arrow a.

As a result, the first cable connected to the first cable 18
The carriage 7 moves at the same speed as the first cable 18 in the direction of arrow b, and the second carriage 10 moves in the direction of arrow c at the radius of the first cable 18 by the principle of a movable pulley.
move in the direction.

Therefore, the first mirror 1 moves in the direction of arrow b at a predetermined speed, and the second mirror 8 moves in the direction of arrow c at half the speed of the first mirror 1.

At this time, the portion 18 1 of the first cable 18 wrapped around the first and second auxiliary fixed pulleys 20 and ₂₁ is
Since the amount of movement of the mirror 1, 8 side portion 182 of the first cable 18 is absorbed by the moving pulley ₁₉ , it does not move at all, so the moving body 21 does not move either and the lens 12 is fixed.

Furthermore, when the lens drive motor 31 is driven to rotate the pinion 33, the movable body 21 moves in the direction of arrow d.

As a result, the second cable 23 is moved in the direction of arrow e, and the lens 11 is moved in the direction of arrow f.

On the other hand, when the movable body 21 moves in the direction of the arrow d, the movable pulley 19 moves in the direction of the arrow g at half the speed of the movable body 21, and the second carriage 10 moves in the direction opposite to the arrow c, so the second mirror 8 moves in the direction opposite to the arrow The moving body 21 moves in the direction c at half the speed of the moving body 21.

At this time, the mirror 1, 8 side portion 1 of the first cable 18
Since the movement of 8 ₂ is absorbed by the moving pulley 19, the first
The mirror 1 does not move and can maintain a constant starting position when copying starts.

Here, if the moving distance of the second cable 23, that is, the moving distance of the movable body 21 is l, the moving distance l ₁ of the second two-stage pulley 26 on the feeding side, that is,
The moving distance of the lens 11 is l ₁ =D/d・l, and the moving speed l ₁ of the first two-stage pulley 25 on the feeding side is l ₁ =D/d・l×d/D=l, and the moving body 21 is the same as the moving distance l.

On the other hand, the moving distance l ₃ of the second mirror 8 is l ₃ =1/2l.

Therefore, the moving distance l ₂ of the lens 11 and the moving distance l ₃ of the second mirror 8 are the first and second two-stage pulleys 25,
26 large diameter portions 25b, 26b and small diameter portions 25a, 2
It can be made to vary arbitrarily by changing the ratio with 5b.

Note that the moving body 21 may be moved by a link mechanism or the like.

With the present invention as described above, during variable-magnification copying, part of the outside of the image area C on the surface C' of the photoreceptor can be irradiated with a part of the light reflected from the original by the exposure light source A to neutralize the charge, thereby making it uncharged. .

Therefore, it is possible to prevent the outside of the image area C on the surface C' of the photoreceptor from becoming solid black, thereby extending the life of the cleaning member, improving the replacement cycle of the toner box, reducing dirt inside the copying machine, and reducing developer consumption. It has advantages such as reduction.

Furthermore, since a part of the reflected light from the exposure light source A is used, there is no need to provide any other special light source.

Furthermore, since only the movable light shield 11a and the fixed light shield B are provided, the structure is simple.

In addition, the operation is simple because the operation is only required to move the lens 11b, and there is no need for any other special control operation, and the reliability is improved without malfunctions.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing an embodiment of the present invention;
FIGS. 2 and 3 are diagrams for explaining the operation, and FIG. 4 is a diagram for explaining the movement of the lens and mirror. 11a is a movable light shield, 11b is a lens, A is an exposure light source, B is a fixed light shield, C is a photoreceptor, and C' is the surface of the photoreceptor.

Claims (1)

[Claims] 1. In an exposure device for an electronic copying machine in which the magnification is changed by moving the lens 11b on the optical path,
A lens 11b provided outside the lens 11b
A moving light shielding body 11a that moves together with the light shielding body 11a and a fixed light shielding body B provided on the optical path are provided. When the reflected light is irradiated onto the photoreceptor surface C' only through the lens 11b, and when the lens 11b and the movable light shield 11a are moved for variable magnification copying, a part of the reflected light is irradiated onto the photoreceptor surface C' through the lens 11b. In addition to irradiating only a part B of C', a passage gap for the reflected light is created between the fixed light shield B and the movable light shield 11a, and a part of the reflected light is transmitted from the passage gap to the photoreceptor surface C'. An exposure device for an electronic copying machine, characterized in that the exposure device is arranged in a positional relationship such that a portion outside the image area C is irradiated with light.