JPH059717Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a variable magnification mechanism suitable for application to an image exposure section of an image forming apparatus such as a copying machine.

[Background of the idea]

Generally, an image exposure section of an image forming apparatus is provided with a variable magnification mechanism for enlarging or reducing a document placed on a document table glass. This magnification change is performed by the imaging lens and the movement of the V mirror. To move this imaging lens, a pulley fixed to a rotating shaft connected to a forward/reverse motor is used, and to move the V-mirror, a rotary variable magnification cam fixed to the shaft and a roller on the outer periphery of the variable magnification cam are used. A swinging lever is used that slides and swings through the shaft.

However, normally, the variable magnification cam has a fixed point that defines the minimum reduction position and the maximum expansion position of the V mirror adjacent to the outer periphery on which the rollers of the swinging lever that move the V mirror from the minimum reduction position to the maximum expansion position slide. Therefore, if the variable magnification cam still rotates even after the rollers of the swing lever have reached the fixed point of the maximum enlargement position, the rollers will move from the fixed point of the maximum enlarged position to the fixed point of the minimum reduced position at once. There was a risk of being depressed. Such an accident not only renders the variable power mechanism itself inoperable, but also renders the entire device inoperable.

[Purpose of invention]

In view of the above, this invention aims to provide a zoom mechanism that prevents the zoom cam from rotating any further when the roller of the swing lever that slides against the zoom cam reaches the demarcation point of the maximum enlargement position on the cam, thereby preventing the roller from dropping from the demarcation point of the maximum enlargement position to the demarcation point of the minimum reduction position in one go.
Another object is to provide such a zoom mechanism at low cost by simplifying its structure.

[Structure of the invention] In order to achieve the above object, this invention has the minimum reduction position and maximum expansion position of the V mirror on the outer periphery where the rollers of the swinging lever that move the V mirror from the minimum reduction position to the maximum expansion position slide. In a variable magnification mechanism equipped with a rotary variable magnification cam in which fixed points to be defined are adjacent to each other, a detachment prevention claw of a roller protruding outward in a horn shape is provided continuously to the fixed point of the maximum enlarged position of the variable magnification cam. It is configured so that it is provided.

〔Example〕

Next, this invention will be explained based on drawings of an image forming apparatus that forms an image by exposing manuscript information onto a photosensitive material and then developing it.

In FIG. 1, 10 is an image exposure section, 20 is a photosensitive material feeding section, 30 is a conveying section, 40 is a developing processing section, and 50 is a drying section.

The image exposure section 10 includes a document table glass 11, a light source 12, a first mirror 13, a second mirror 14, a third mirror 15, an imaging lens 16, and a shutter 17. A first scanning unit A consisting of the light source 12 and a first mirror 13 moves parallel to the document table glass 11 to expose and scan the document, and a second scanning unit A consisting of a second mirror 14 and a third mirror 15 moves parallel to the document table glass 11 to expose and scan the document. (hereinafter referred to as the V mirror) b is mounted on a moving table and moves in the same direction as the first unit A and at half the moving speed, and optically moves from each scanning position on the document to the imaging section. The length of the path is kept constant. This image exposure section 10 is almost similar to that used in known electrophotographic copying machines, but uses an odd number of mirrors to invert the image and expose a latent image corresponding to the original image. It is designed to be formed directly on the photosensitive surface of the material. The shutter 17 opens an exposure window 37 provided on one side wall of the light-shielding box 100 housing the image exposure section 10 during exposure scanning, and otherwise closes it to prevent miscellaneous light from leaking from the exposure section of the transport section 30. This is how it was done.

The paper feed section 20 has a magazine 21 in which the photosensitive material is wound in a roll and stored in a light-tight manner removably disposed therein, and also has a pull-out roller 23 and a drawer. A cutting device 24 is provided to cut the end when it reaches a predetermined length.

The conveying section 30 includes a path 34 having conveying rollers 31, 32, and 33 for photosensitive material cut into a predetermined length, and a first accumulator 35 provided above the path 34 for once winding up and storing the photosensitive material.
and a second accumulator 36 provided below the path 34. The conveyance roller 31~
Reference numeral 33 is a device that can be rotated forward and backward, and transfers the photosensitive material fed from the paper feed section 20 to the first accumulator 35.
After being transported to the second accumulator 36, it is reversed and
lower towards. This second accumulator 3
6, the photosensitive material passes through the exposure window 37 of the image exposure section 10, during which the original image is exposed. Therefore, the speed of the photosensitive material during this downward movement is synchronized with the light source scanning speed. The exposed photosensitive material accommodated in the second accumulator 36 is again accommodated in the first accumulator 35 by the conveyance rollers 31 to 33, and the switching claw 38 provided in the middle of the path 34 is switched. As a result, it is guided to a passage 34' communicating with the development processing section 40, and is sent to the development processing section 40 by a conveyance roller 39 provided in the passage 34'.

The development processing section 40 includes a first developer tank 41A and a second developer tank 4 in a housing 40' that can be pulled out from the main body of the apparatus.
1B, a bleach-fix tank 41C, a first stabilization tank 41D, and a second stabilization tank 41E. This is to facilitate inspection and repair of the inside of each tank, inspection and repair of the drive system and replenishment circulation system, and removal of jamming of photosensitive material generated in the transport system within the tank. At the entrance of the first developing tank 41A, there is a guide roller 42 that guides the photosensitive material fed into the tank by the conveying roller 39 provided in the passage 34'.
is provided.

The photosensitive material guided to the first developer tank 41A passes through a plurality of groups of submerged conveyance rollers 44 provided in a passage 43 filled with processing liquid, and reaches the second developer tank 41B, whereupon the photosensitive material discharged from the second developer tank 41B The material is then sent to the bleach-fixing tank 41C via a transfer roller 45 provided outside the solution, and similarly from the bleach-fixing tank 41C to the first stabilizing tank 41D and from the first stabilizing tank 41D to the second stabilizing tank 4.
1E, the photosensitive material that has undergone all the development processes through the final tank 41E is sent to the drying section 50 via a conveying roller 46 provided at its exit. In this drying section 50, the photosensitive material is sandwiched between a conveyance roller 51 and a conveyance wire 52, and its upper and lower surfaces are dried with hot air by a hot air dryer 53, and then discharged from the apparatus through a discharge roller 54.

In addition, in the first developing tank 41A, there is an exposure tube 4 having an exposure window 47a facing the photosensitive material passage 43.
7b and a lamp house 47 provided above it.
The light from C can be applied to the photosensitive material as reverse exposure.

The imaging lens 16 of the image exposure section 10 is a second
It is provided on the moving table 161 as shown in FIG.
The V-mirror is also moved to the left side when enlarging the original, and to the right when reducing the original.
It moves in a predetermined direction in synchronization with the movement of and is reset. The moving stage 161 of the imaging lens 16 is a wire 103 wound around a pulley 102 fixed to a rotating shaft 101 connected to a forward/reverse motor (not shown).
moored to and moved. The V-mirror B includes a variable magnification cam 104 fixed to the shaft 101, and a wire 1 interlocked with the action of a swinging lever 106 that slides on the outer periphery of the conversion cam 104 via rollers 105.
07 and an endless wire 108 connected to the wire 107 to move.

The variable magnification cam 104 has a minimum diameter at a defining point _P1 that defines the minimum reduction position of the V mirror on the outer periphery where the roller of the swinging lever slides, and expands from this point to the V mirror.
A shape in which the range from plane P ₂ to P ₃ that defines the mirror's equal magnification position is the maximum, and the area that passes beyond P ₃ to the demarcation point P ₄ that defines the maximum enlarged position of the V mirror gradually decreases. It's getting old. The defined point P ₁ that defines the minimum reduction position of the V-mirror and the defined point P ₄ that defines the maximum enlarged position are adjacent to each other. Therefore, when the imaging lens is at the same magnification position, when the pulley 102 is rotated (clockwise) in the reduction direction from that position, the imaging lens moves to the right and the V mirror moves to the left. On the other hand, when the pulley 102 rotates (counterclockwise) from the same magnification position toward the enlargement direction, the imaging lens moves to the left and the V mirror moves slightly to the left.

The variable magnification cam 104 is provided on the outer periphery thereof and continues outward from a defining point _P4 that defines the maximum enlarged position of the V mirror, which is adjacent to a defined point _P1 that defines the minimum reduced position of the V mirror. A horn-shaped protruding claw 104a is provided to prevent the roller of the swing lever from coming off. That is, after the variable magnification cam 104 rotates counterclockwise and the roller 105 of the swing lever 106 reaches a fixed point _P4 that defines the maximum enlarged position of the V mirror, the variable magnification cam attempts to rotate further. This is to prevent the roller 105 from falling all at once from P ₄ to the adjacent P ₁ . In other words, the variable magnification cam 104 has rollers 105 that prevent it from coming off.
4a, further rotation is restricted.

In addition, 181 is a movable light-shielding frame that covers the imaging lens 16, and 182 is a fixed light-shielding frame that covers the exposure window 37. Both frames overlap more than the moving area of the imaging lens 16, and there is a gap between the two frames. A thin plate-like body 183 made of Mylar or the like is provided with one end fixed to the side wall and upper wall of the movable light-shielding frame 181 to prevent stray light from entering.

[Effect of idea]

As explained above, this invention has a fixed point that defines the minimum reduction position and maximum expansion position of the V mirror adjacent to the outer periphery where the rollers of the swinging lever that move the V mirror from the minimum reduction position to the maximum expansion position slide. In a variable magnification mechanism equipped with a rotary variable magnification cam,
The feature is that a roller detachment prevention pawl that protrudes outward in a continuous horn shape is provided at the defining point of the maximum enlargement position of the variable magnification cam, so that the rotation of the variable magnification cam makes sliding contact with the claw. When the roller of the lever reaches the fixed point of the maximum enlargement position on the cam, the variable magnification cam cannot rotate any further even if it tries to rotate, and therefore the roller moves from the fixed point of the maximum enlargement position to the fixed point of the minimum reduction position. It is possible to eliminate accidents that cause sudden decline. Moreover, it has an excellent effect of being simple in structure and inexpensive.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an image forming apparatus to which this invention is applied, FIG. 2 is a plan sectional view of the main part, and FIG. 3 is a side sectional view of the same. 10... Image exposure section, 16... Imaging lens, 1
04... Variable power cam, 104a... Roller removal prevention claw, 105... Roller, 106... Rocking lever, B
...V mirror.

Claims (1)

[Claims for Utility Model Registration] (1) A fixed point that defines the minimum reduction position and maximum expansion position of the V mirror on the outer periphery where the rollers of the swinging lever that move the V mirror from the minimum reduction position to the maximum expansion position slide in contact. In a variable magnification mechanism equipped with a rotary variable magnification cam adjacent to the variable magnification cam, a claw for preventing the roller from coming off and protruding outward in a horn shape is provided continuously at a defining point of the maximum enlarged position of the variable magnification cam. Features variable magnification mechanism. (2) The variable power mechanism according to claim 1, wherein the variable power cam is fixed coaxially with a pulley that moves the imaging lens to a variable power position.