JPH0668650B2 - Image forming device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for performing slit exposure scanning of an original image on a moving photoconductor.

(Prior Art) As a conventional image forming apparatus, a leader printer for enlarging and projecting a frame image of a microfilm by a projection lens and forming a copy image on a transfer material such as paper will be described as an example. The configuration is as shown in the figure. In the figure, reference numeral 101 denotes a microfilm which is an original image. A frame image of one frame of the microfilm is illuminated by an illumination lamp 102 and a condenser lens 103, and the projection lens 10
4 and the slits provided on the light shielding member 107 through the plane mirrors 105 and 106 which face each other at right angles and move in the arrow A direction.
The photosensitive member 108 rotating in the direction of arrow B is subjected to slit exposure through 107a. The surface of the photoconductor 108 is uniformly charged by the charger 109, and the image exposure described above is performed in the exposure unit to form an electrostatic latent image corresponding to the frame image of the microfilm 101. Further, the toner image of the developing device 110 is developed, and the toner image is transferred to the transfer material 113 by the transfer discharger 112. The toner image on the transfer material 113 is fixed by a fixing device (not shown). On the other hand, the toner remaining on the photoconductor 108 after transfer is cleaned by the blade 114 of the cleaning device 114.
The charges are scraped off by a, and the charges on the photoconductor 108 are further discharged by the discharging lamp 115, and the process returns to the first step.

Here, not only the image portion of the microfilm 101 but also the front end side (upstream side in the rotation direction of the photoreceptor) and the rear end side (downstream side in the rotation direction of the photoreceptor) of the image portion are charged to the photoreceptor 108, If the image is developed as it is, the toner adheres to the front end side and the rear end side of the image portion, resulting in waste of the toner and a burden on the cleaning unit 114. Therefore, when a positive copy image is conventionally taken from a negative original image (hereinafter referred to as a negative-positive), toner adhesion can be prevented by maintaining the potential of the surface of the photoconductor 108. Therefore, the shutter 116 is provided at the image exposure portion. A method is provided in which the slit 107a of the light shielding member 107 is opened only in a predetermined image area and is closed in the non-image area on the front end side and the rear end side of the image area.

On the other hand, when a positive copy image is taken from a positive original image (hereinafter referred to as a positive-negative), light can be applied to the photoconductor 108 to lower the potential, so that the potential between the charging device 109 and the developing device 110 is reduced. An exposure apparatus is provided in the above, and the exposure is applied to the non-exposure area by this method.

(Problems to be Solved by the Invention) However, in the case of such a conventional example, for example, in the case of a negative-positive, as shown in FIG. If 116 is synchronized with the peripheral speed of the photoconductor 108, a-b-c and a-b-c are detected at the leading and trailing end positions of the image area on the photoconductor corresponding to the leading and trailing ends of the frame image of the microfilm 101. The d-e-f and the exposure amount increase or decrease, and the leading end position and the trailing end position of the image area become clear. However, when the shutter 116 is not synchronized with the moving speed of the photoconductor 108, the ac and df and the exposure amount change with an inclination at the boundary between the image portion and the non-image portion. That is, even if the amount of light is constant, the amount of exposure on the photoconductor 108 changes, and this appears as a change in density when developing with toner.
Further, as shown in FIG. 8, when the shutter 116 opens in the same direction C as the rotation direction of the photoconductor 108, the operation of the shutter 116 is performed by the photoconductor 1.
It can be synchronized with 08, but when closed
It is impossible to synchronize because it is opposite to the rotation direction of 8. Therefore, such a shutter mechanism has a problem in that it is not possible to prevent a change in density at both the leading edge and the trailing edge of an image at the same time.

In the case of positive-positive, the exposure device that irradiates the non-image area on the photoconductor has a constant exposure width. Therefore, as in the case of negative-positive, as shown in FIG. However, there is a problem in that the density of the toner image is also changed due to the inclination of the exposure amount such as the front end and the rear end gh, i-j.

In particular, for the purpose of preventing the toner from scattering during transfer, which is one of the major causes of jamming and in-machine contamination due to toner scattering due to the winding of the transfer material 113 around the fixing roller, the image should be prevented from protruding from the transfer material. If you want to put a margin at the tip of the transfer material 113 so that the inside of the transfer material 113 is formed,
This density change that occurs at the boundary between the non-image part and the image part appears on the copied image, resulting in a hazy and poorly imaged image.
There was a problem that the image quality would be significantly deteriorated.

The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to eliminate density unevenness occurring at the front and rear edges of an image in both negative-positive and positive-positive cases. An object of the present invention is to provide an image forming apparatus capable of obtaining a sharp copy image.

(Means for Solving Problems) In order to achieve the above-mentioned object, the first invention has a movable photoconductor and a light source for forming a non-image portion on the photoconductor. In an image forming apparatus capable of forming an image on each of a blank original and a negative original, a light blocking member having an opening for transmitting light, and an opening provided on the upstream side of the light path of the light blocking member for transmitting light. A shutter provided with a portion, the light shielding member is fixed, the shutter moves in the same direction as the moving direction of the photoconductor and at a synchronized speed, and a first position aligned in the moving direction. , A second position, and a third position. In the case of a positive original, the light source is turned on, and when the shutter is in the first position, the shutter blocks the image optical path and the light from the light source is removed. The light passes through the openings of the shutter and the light shielding member to the photoconductor When the shutter is in the second position, the shutter blocks the light from the light source so that it is not guided to the photoconductor and opens the image optical path. Light is guided to the photoconductor through the opening of the light blocking member and an image portion is formed. When the shutter is at the third position, the shutter blocks the image light path, and the light from the light source opens the shutter and the light blocking member. In the case of a negative document, the light source is turned off and the shutter moves the image optical path when the shutter is in the first position. When the shutter is at the second position, the shutter opens the image light path to guide the image light to the photoconductor through the opening of the light shielding member to form the image portion. , Above Data is the aforementioned shutter when in the third position, characterized in that the non-image portion of the image rear end blocking the image light path is formed.

The second invention has a movable photoconductor and a light source for forming a non-image portion on the photoconductor, and an image can be formed on each of a void original and a negative original. The image forming apparatus has a light blocking member having an opening for transmitting light, and a shutter provided on the upstream side of the light path of the light blocking member and having an opening for transmitting light, and the light blocking member is fixed. Therefore, the shutter moves in the same direction as the moving direction of the photoconductor and at the same speed, and the first position and the second position are aligned in the moving direction.
, And a third position. A fixed mirror that bends the light from the light source toward the opening is provided at the front edge of the shutter opening in the shutter moving direction, while the shutter opening of the shutter opening is moved in the shutter moving direction. A movable mirror is provided at the trailing edge, and there are a first mirror position where light from the movable mirror light source to the fixed mirror is blocked and bent toward the opening side, and a second mirror position where light from the light source passes to the fixed mirror. , In the case of a positive original, the light source is turned on, and when the shutter is at the first position, the fixed mirror of the shutter blocks the image optical path and the movable mirror is moved. As the second mirror position, the light from the light source is bent by the fixed mirror and guided to the photoconductor through the openings of the shutter and the light shielding member to form the non-image portion at the tip of the image portion. When the shutter is in the second position, the light from the light source, which is bent by the fixed mirror and passes through the shutter opening, is blocked by the light blocking member so as not to be guided to the photoconductor and the light path of the image is prevented. The image portion is opened and the image light is guided to the photoconductor through the opening of the light shielding member to form the image portion.
When the movable mirror is set to the first mirror position, the movable mirror cuts off the image optical path by the movable mirror, and the light bent from the movable mirror from the light source is guided to the photoreceptor through the opening of the shutter and the light shielding member. In the case of a negative document, the light source is turned off, the movable mirror is set to the second mirror position when the shutter is in the first position, and the shutter is fixed. A non-image part at the tip of the image part is formed by blocking the image light path by the mirror, and when the shutter is in the second position, the fixed mirror of the shutter opens the image light path and allows the image light to pass through the opening of the light shielding member. When the image section is formed on the photoconductor and the shutter is at the third position, the movable mirror is set as the first mirror position to block the image optical path by the movable mirror and the rear end of the image section. The non-image part of is formed.

(Example) Below, this invention is demonstrated based on the Example shown in figure. First
The figure shows a main part of a reader printer to which an image forming apparatus according to an embodiment of the second invention is applied, and those having the same functions as those of the apparatus of FIG. 8 are denoted by the same reference numerals. Then, 1 is a light shielding member provided with a slit 1a as an opening. Numeral 2 is a shutter which is arranged to face the light shielding member 1, and as shown in FIG. 2, is attached to the shaft of the photoconductor 108 via a shaft 3 and a rail 4 which are arranged in parallel at an interval of the length of the photoconductor 108. On the other hand, it is slidable with respect to the light shielding member 1 in the right-angled direction (left-right direction in the drawing). That is, Shatter 2
On one side, a first support portion 5 and a second support portion 6 which are arranged at right angles to the shutter surface at a rising interval are slidably fitted to the shaft 3. A roller 7a is provided on the other side end of the shutter 2 via a shaft 7,
It is supported by the rail 4 described above.

Further, a compression spring 8 is mounted between the second shaft fixing portion 9b at one end of the shaft 3 and the second supporting part 6 of the shutter 2 described above, and the second supporting part 6 is attached to the shaft 3
The shutter 2 is positioned at the initial setting position by urging the other end of the shaft supporting member 5 toward the first shaft fixing part 9a to press the first supporting part 5 against the first shaft fixing part 9a.

The shutter 2 is provided with an opening 10 capable of overlapping with the slit 1a of the light shielding member 1, and the edge of the opening 10 on the side of the second shaft fixing portion 9b (the front edge in the moving direction of the shutter 2). ,
A fixed mirror 11 which stands up at a 45 degree angle in a clockwise direction from the surface of the shutter is provided, and is provided on the light shielding member 1 by shielding the image light from the original image from the upper surface at the initial setting position of the shutter 2 described above. The slit 1a is closed. The anti-slope 11a of the fixed mirror 11 is on the lower surface side, and is not provided on the reflecting surface in the light-shielding portion on the upper surface side. On the reflective surface, as described below, in the case of positive-positive, the static elimination lamp
The light of 115 is reflected to expose the photoconductor 108. A movable mirror 12 is attached to the other edge of the opening 10 (the trailing edge in the moving direction of the shutter 2). The movable mirrors 12 are rotatably attached to both sides of the shutter 2 via a shaft 13 attached to one end of a support portion 12a that stands up at a right angle to the shutter surface. Further, it is urged in the clockwise direction by a spring (not shown), and its free end has a roller.
14 is attached and is pressed against the upper surface of a guide member 15 which is arranged on the light shielding member 1 in parallel with the shaft 3.
As shown in FIGS. 4 and 5, the guide member 15 has a groove 15 as shown in FIG.
a is formed, and a torsion spring 15b is attached to a shaft 15c implanted in the guide member 15 such that one end 15d of the torsion spring 15b exerts an urging force in the counterclockwise direction and closes the groove 15a.

Next, the shutter actuating means for actuating the shutter 2 will be described in detail. Reference numeral 16 in the drawing is a spring clutch using a known clutch spring or the like, and is composed of a gear 17, a control ring 18, an intermittent gear 19 integrated with the control ring 18, and a clutch spring (not shown). The drive of the drum gear 20 that rotates integrally with the photoconductor is transmitted to the gear 17 via the intermediate gear 21, and the gear 17 always rotates clockwise. The control ring 18 has a first groove 22 as shown in FIGS.
And a second groove 23 are provided, the first groove 22 being the control ring 18
The second groove 23 is formed in only about half over the entire width direction. On the other hand, the first lever 24 for controlling the spring clutch 16,
The second lever 25 is rotatably provided in parallel with each other with the rotary shafts 24a and 25a as fulcrums. And the first lever
The claw portion 24b provided at the tip of the first groove 24 and the second groove 23
The second claw portion 25 provided at the tip of the second lever 25 on both
b is designed to engage only in the first groove 22.
The lever 24 and the second lever 25 are springs, respectively.
It is biased counterclockwise by 24c and 25c. Also the first
The lever 24 has a protrusion protruding toward the second lever 25 side.
24d is provided, and this projection 24d is fitted in a notch portion 25d 'provided in the second lever 25. On the other hand, the first lever 24 is provided with a plunger 26 on the opposite side to the spring 24c, that is, the plunger 26 for pulling the first lever 24 in the clockwise direction is pulled, and the solenoid 26 is energized to pull the plunger 26. Therefore, when the plunger 26 is pulled, the second lever 25 is pulled together with the first lever 24, and the plunger 26 is rotated clockwise.

By thus energizing the solenoid 27, the claw portions 24b, 25b of the first lever 24 and the second lever 25 are moved to the first groove 2
2, the drive of the drum gear 20 is transmitted to the intermittent gear 19 by the spring clutch 16. On the other hand, a rack 29 that engages with the intermittent gear 19 is attached to the lower surface of the shutter 2 so that the shutter 2 can be moved rightward in the drawing by the number of teeth of the intermittent gear 19 in synchronization with the rotational speed of the photoconductor 108. I'm running.

Further, the shutter actuating means is provided with a mechanism for preventing malfunction of the shutter. This is the second lever 25 described above.
And an L-shaped return lever 28 that abuts on the top 25e of the second lever 25, and a rod-shaped restricting lever 31 that restricts the movement of the return lever 28 depending on the position of the scan mirror unit 30. As shown in FIG. 3, the return lever 28 is rotatably attached to the support shaft 32, and has a first arm 33 extending horizontally from the support shaft 32 to one side and a first arm 33 with respect to the first arm 33. It is composed of a second arm 34 extending upward at a right angle and a first arm.
The tip portion 35 of 33 extends downward in a right angle direction. The tip portion 35 is the top surface 25e of the second lever 25 and the first lever 24.
Is in contact with the tip surface 24e of the. A spring for biasing the first arm 33 in the counterclockwise direction about the support shaft 32 is provided on the first arm 33.
36 'is attached to the second lever by the tip 35.
The top surface 25e of 25 is pressed. On the other hand, the second arm 34 has a roller 3
6 is installed. On the other hand, the restriction lever 31 extends in the vertical direction and is rotatable about a support shaft 37, and the lower end of the restriction lever 31 comes into contact with the roller 36 of the return lever 28. The upper end of the regulation lever 31 is pushed by the pin 38 when the skimming mirror unit 30 reaches the initial setting position (the position indicated by the solid line in the figure), and the regulation lever 31 is rotated clockwise to move the return lever 28. The lower end of the restricting lever 31 is separated from the roller 36 of the second arm 34 to allow the return lever 28 to rotate counterclockwise. A spring 39 for urging the regulation lever 31 in the counterclockwise direction is attached to the lower end side of the regulation lever 31, and when the skimming mirror unit 30 is not in the initial setting position, the regulation lever 31 is rotated in the counterclockwise direction. The second arm 34 of the return lever 28 is pressed in the clockwise direction via the roller 36 to regulate the counterclockwise rotation of the return lever 28. Numeral 40 is a stopper for restricting the clockwise movement of the return lever 28, which keeps the first arm 33 of the return lever 28 horizontal and holds the restriction lever 31 vertically.

Reference numeral 41 denotes a cover which is integrated with the light shielding member 1 and is provided with an opening 42 through which the image light from the original image passes and serves as a light source arranged between the charger 109 around the photoconductor 108 and the cleaning device 114. A reflection mirror 43 is provided which forms an optical path for guiding the light of the static elimination lamp 115 to the exposure unit. That is, the reflection mirror 43 is disposed so as to face the fixed mirror 11 provided in the shutter 2 and the static elimination lamp 11 is incident on the reflection mirror 43 at an incident angle of 45 degrees.
Light from 5 is incident. A shutter plate 45 that opens and closes the passage 44 is provided in the passage 44 that guides the light of the static elimination lamp 115 to the reflection mirror 43 between the cover 41 and the tip of the light shielding member 1. The shutter plate 45 is rotatable about the support shaft 46.In the case of positive-positive, the shutter plate 45 is held at the position indicated by the solid line to guide the light of the static elimination lamp 115 to the exposed portion, and in the case of negative-positive, the shutter plate 45 is used. The plate 45 is held at the position shown by the alternate long and two short dashes line so that the passage 44 is closed and the light of the static elimination lamp 115 is cut. The shutter plate 45 is operated and controlled by a positive-positive or negative-positive switching signal, an electric means such as a solenoid, or a mechanical means such as a lever.

In the above configuration, the print operation in the case of negative-positive will be described first. When the switching switch (not shown) is switched to select negative-positive, the shutter plate 45 is closed and the light from the static elimination lamp 115 is blocked. When the skiyan mirror unit 30 is in the position shown by the solid line in FIG. 1,
The frame image of the microfilm 101, which is the original image, passes through the projection lens 104 by the illumination lamp 102 and the condenser lens 103, and is projected on the screen (not shown) via the plane mirror (not shown) to be in a reader state. ing. Sukiyan mirror unit 30 by turning on the print switch
Moves to the left in the figure. The solenoid 27 is energized when the image is inverted by a clutch operation (not shown) and reaches the image start point a. Then, the first lever 24 is rotated clockwise by the plunger 26, and the claw portion 24b of the first lever 24 is rotated.
Is disengaged from the first groove 22 of the control ring 18. At the same time, the second lever 25 is also rotated in the clockwise direction in cooperation with the first lever 24 by the projection 24d of the first lever 24 fitted in the cutout 25d of the second lever 25. The claw portion 25b of the second lever 25 is also removed from the first groove 22. As a result, the gear 17 and the intermittent gear 19
Is connected, and the drive from the drum gear 20 is transmitted to the rack 29 to move the shutter 2 against the compression spring 8 to the right in the figure. Then, as shown in FIG. 6 (a), the image light 47, which has been blocked by the fixed mirror 11 until then, is projected onto the photoconductor 108 as the shutter 2 moves. The movement speed of the shutter 12 is synchronized with the peripheral speed of the photoconductor 108 because the driving force is obtained from the drum gear 20 that rotates integrally with the photoconductor 108 of the shutter 2, and the photoconductor 108 is exposed. The boundary between the image area and the non-image area is as shown by abc in FIG. 9 (a). That is, the fixed mirror of the shutter 2
The upper surface of 11 causes the slit 1a to open in synchronization with the peripheral speed of the photoconductor 108. Even after the slit 1a is completely opened (state of FIG. 6 (b)), the shutter 2 further moves, the roller 14 of the movable mirror 12 moves along the upper surface of the guide member 15, and the roller 1 of FIG. When the state is reached, the claw portion 24 of the first lever 24
b is engaged with the second groove 23 of the control ring 18, the drive from the drum gear 20 is stopped, and the shutter 2 stops at that position. Then, as described above, the image light 47 is slit-exposed through the slit 1a on the photoconductor 108 uniformly charged by the charger 109 to form a latent image. Further, this latent image is developed by the toner 111 of the developing device 110, and is transferred by the transfer discharging device 112 to the transfer material 113 sent in time with the image. On the other hand, the toner remaining on the photoconductor 108 is scraped off by the blade 114a of the cleaning device 114, and the charge is erased by the static elimination lamp 115, and the process returns to the first step. These copying steps are similar to those of the conventional example described above.

Next, when the scan mirror unit 30 reaches the C position where the image exposure ends, the solenoid 27 is energized again and the first
The claw portion 24b of the lever 24 is disengaged from the second groove 23 of the control ring 18, the gear 16 and the intermittent gear 19 are connected and driven, and the shutter 2 moves to the right in the drawing of FIG. Then, the slit 1a is closed by the movable mirror 12 from the state of FIG. 6 (c) to the state of (d) in synchronism with the peripheral speed of the photoconductor 108, as shown in FIG. 9 (a). , The change in the exposure amount at the rear edge of the image area is as d-e-f. When the slit 1a is completely closed and the image light reaches the position shown in FIG. 6 (d) where the image light is completely blocked, the toothless portion 19a of the intermittent gear 19 is formed, and the rack 29 and the intermittent gear 19 mesh with each other. The shutter 2 is disengaged, and the shutter 2 is instantly pushed leftward in the figure by the compression spring 8 to return to the state shown in FIG. And the first groove 22 of the control ring 18
When the claw portion 24b of the first lever 24 is engaged with the drive gear, the drive connection is disconnected and the intermittent gear 19 stops rotating. While the shutter 2 is returning, the opening 10 passes over the slit 1a and the light from the image strikes the photoconductor 108. Therefore, toner may adhere to the exposed area, but the exposure time is extremely short and the area is a limited narrow range, and it does not appear on the copy image because it is a non-image area. So
There is no waste of toner and no damage to the cleaning device 114. The static elimination lamp 115 is turned off by cutting the light of the static elimination lamp 115 by the shutter plate 45, and as shown in FIG. 6 (a), the movable mirror 12 is at the second mirror position and the fixed mirror 11 is The position of the shutter 2 where the image optical path is blocked and the non-image portion at the leading end of the image portion is formed is referred to as a first position.

Then, as shown in FIGS. 6B and 6C, the fixed mirror 11 of the shutter 2 opens the image light path to guide the image light to the photoconductor 108 through the slit 1a of the light shielding member 1 and the image portion. The position of the shutter 2 in which is formed is called the second position.

Further, as shown in FIG. 6D, the movable mirror 12 of the shutter 2 is set to the first mirror position to block the image optical path by the movable mirror 12 to form the non-image portion at the rear end of the image portion. The position of is called the third position.

Here, the movement of the movable mirror 12 will be described in detail with reference to FIGS. 4 and 5. The movable mirror 12 interlocks with the movement of the shutter 2 and blocks the light from the static elimination lamp 115 to the fixed mirror 11 and bends it toward the opening 10 side (see FIGS. 6C and 6D). ), And can move to the second mirror position where the light from the static elimination lamp 115 passes to the fixed mirror 11 (see FIGS. 6A and 6B).
That is, when the shutter 2 moves to the right, the movable mirror 12
The rollers attached to the pass through without falling into the groove 15a,
It moves along the guide member 15 as indicated by the arrows a-b-c, and reaches the tilted first mirror position as shown in FIGS. 6 (c) and 6 (d). When the rack 29 is disengaged from the meshing of the intermittent gear 19 and the shutter 2 is pushed back by the compression spring 8, the roller 14 provided at the tip of the movable mirror 12 passes through the groove 15a provided in the guide member 15 and is indicated by the arrow d. , e, the torsion spring 15b is flipped up to return to the position shown in FIG. 6A (second mirror position). By doing so, the impact on the movable mirror 12 at the time of returning can be reduced.

Next, the printing operation in the case of positive-positive will be described. When the changeover switch (not shown) is changed to positive-positive, the shutter plate 45 is in the open state shown by the solid line in FIG. 1, and when the print switch is turned on, the scan mirror unit 30 moves to the image starting point a. , The solenoid 27 is turned on at the same time as the image scanning, and the shutter 2 becomes the photoconductor 108.
The movement in synchronism with the peripheral speed is the same as in the case of the negative-positive.

In the case of positive-negative, the light of the static elimination lamp 115 is reflected by the reflection mirror 43.
And the fixed mirror 11 and the slit 1a through the photoreceptor 10
Illuminated on 8. Then, as the fixed mirror 11 shifts from the slit 1a as the shutter 2 moves,
The light of the static elimination lamp 115 vignets at the right end portion of the slit 1a, and the shutter 2 is completely opened, that is, the image light 47 does not vignet the fixed mirror 11 and completely strikes the photoconductor 108 through the slit 1a. Static elimination lamp 115 in the state of (b)
This light is completely blocked by the light blocking member 1. Since the shutter 2 is also synchronized with the photoconductor 108 in terms of the vignetting of the light of the static elimination lamp 115, the exposure amount is g− shown in FIG.
It becomes like kh. Then, the shutter 2 further moves, and when the roller 14 of the movable mirror 12 moves along the upper surface of the guide member 15 to reach the state shown in FIG. 6C, the claw portion 24b of the first lever 24 becomes the control ring 18. The drum gear 2 is engaged with the second groove 23.
The drive from 0 is cut off, and the shutter 2 stops at that position.

Further, the copying process after the slit exposure through the completely opened slit 1a is the same as in the case of the negative-positive.

When the scan mirror unit 30 reaches the C position where the image exposure ends, the solenoid 27 is energized again, the claw portion 24b of the first lever 24 is disengaged from the second groove 23 of the control ring 18, and the drive is connected. The shutter 2 is moved again in synchronization with the photoconductor 108. As the shutter 2 moves, the light from the static elimination lamp 115 starts to strike the photoconductor 108 by the movable mirror 12, and the exposure amount at the boundary with the non-exposed image area on the rear end side of the image area is shown in FIG. It becomes i-l-j as shown. After that, when the shutter 2 further moves and reaches the position shown in FIG. 6 (d), it becomes the toothless portion 19a of the intermittent gear 19, and the rack 2
The mesh with the intermittent gear 19 of 9 is disengaged, and the shutter 2 is instantly pushed to the left by the compression spring 8 to return to the state shown in FIG. Then, when the claw portion 24b of the first lever 24 is engaged with the first groove 22 of the control ring 18, the driving is stopped and the intermittent gear 19 stops rotating. When the movable mirror 12 returns to the horizontal position as shown in FIG. 6 (a) when the shutter 2 returns, a state where the light of the charge eliminating lamp 115 does not hit the photoconductor 10 occurs, and toner adheres to the photoconductor 108. However, since the time is extremely short and the area is limited to a limited narrow range, the toner adhesion amount is very small and is not a problem in practical use. As shown in FIG. 6 (a), the movable mirror 12 is set to the second mirror position, the fixed mirror 11 blocks the image optical path, and the light from the static elimination lamp 115 is released from the shutter 2.
Through the opening 10 and the slit 1a of the light shielding member 1
The position of the shutter 2 where the non-image portion at the leading end of the image portion is formed by being guided to 108 is the first position as in the case of the negative-positive.

Further, as shown in FIG. 6B, the light from the static elimination lamp 115 bent by the fixed mirror 11 is applied to the photosensitive member 1.
The position of the shutter 2 where the image portion is formed by guiding the image light to the photoconductor 108 through the slit 1a of the light shielding member 1 while blocking the light by the light shielding member 1 so as not to be guided to 08 The second position is the same as in the above case. Further, as shown in FIG. 6D, the movable mirror 12 is set to the first mirror position to block the image optical path by the movable mirror 12 and the light from the charge eliminating lamp 115 is emitted from the shutter. The position of the shutter 2, which is guided to the photoconductor 108 through the opening 10 and the slit 1a of the light shielding member 1 to form the non-image part at the rear end of the image part, is the third position as in the case of the negative-positive.

Regarding the movement of the movable mirror 12, the movable mirror 12 is kept until the time when the shutter 2 is completely opened as shown in FIG.
Is a static elimination lamp 1 which is given to the photoconductor 108 by the fixed mirror 11.
It must be kept horizontal so that it does not block the 15 lights. After the shutter 2 is completely opened, the static elimination lamp 11 is moved by the movable mirror 12 when the shutter 2 is closed.
In order to apply the light of 5 to the photoconductor 108, it is necessary to bring the movable mirror 12 up to the state of FIG. In order to reduce the shock given to the movable mirror 12 when the shutter 2 returns, it is necessary to change gently from the state shown in FIG. 6B to the state shown in FIG. You must expect 2 moves. However, by the above method, that is, by rapidly changing the movable mirror 12 from the state shown in FIG. 6B to the state shown in FIG. 6C during the forward movement and bringing it to a gentle passage such as the groove 15a during the backward movement. Since the amount of movement of the shutter 2 from the state shown in FIG. 6B to the state shown in FIG. 6C can be reduced, the device can be made smaller.

The operation of the shutter malfunction prevention mechanism will be described below. As shown in FIGS. 1 and 3, when the solenoid 27 is energized by some malfunction and the scan mirror unit 30 is in the position indicated by the solid line, the claw of the first lever 24 is inserted into the second groove 23 of the control ring 18. It is assumed that the portion 24b is engaged. At this time, the regulation lever 31 comes into contact with the pin 38 of the skimming mirror unit 30,
As shown in the solid line position, the return lever 28 is
By the action of, it is possible to rotate counterclockwise. (At the position of the second groove 23, the second lever 25 is at the position of the chain double-dashed line.) That is, since the stopper 25e of the second lever 25 eliminates the stopper, the return lever 28 has the chain double-dashed line of FIG. Move to position. As a result, the first lever 24 is rotated clockwise, the pawl portion 24b is disengaged from the second groove 23, and the gear 17
Drive is connected to the intermittent gear 19 by the spring clutch 16,
Move Shutter 2 to the right. At the same time, when the control ring 18 rotates and the claw portion 25b of the second lever 25 engages with the first groove 22, the return lever 28 returns to the state shown by the solid line. Then, the claw portion 24b of the first lever 24 engages with the first groove 22 and returns to the initial state. That is, Sukiyan Mirror Unit 30
When is in the position shown by the solid line, the shutter 2 is always in the state shown in FIG. Skiyan mirror unit 30
When the control lever 31 leaves the position indicated by the solid line, the regulating lever 31 is in the position indicated by the chain double-dashed line and holds the return lever 28 at the position indicated by the solid line. It becomes unrelated.

Next, FIGS. 7 (a), (b) and (c) show the light blocking member 201 and the shutter 2 of the exposure apparatus according to the first embodiment of the present invention.
A schematic diagram of 02 is shown.

In the first embodiment, the light shielding member 201 is provided with an image exposure slit 203 that allows image light to pass therethrough, and a charge-eliminating exposure slit 204 that allows light from the charge-eliminating lamp 115 to pass in the case of positive-positive. , The shutter 202 has a first slit 205, and a second slit 205.
The slit 206 and the third slit 207 are formed. Reference numeral 208 denotes a reflection mirror that guides the light from the static elimination lamp 15 to the exposed portion of the photoconductor 108 when positive-positive, and is provided integrally with the light shielding member 201. That is, as in the case of the first embodiment, in the case of the negative-positive, the optical path from the static elimination lamp to the reflection mirror 208 is blocked by the shutter plate,
In case of negative, it is designed to open the light path.

The shutter operating means for operating the shutter 202 has the same structure as that of the first embodiment, and moves the shutter 202 in synchronization with the photoconductor 108.

In the above configuration, in the case of negative-positive, FIG. 7 (a)
As shown in, the image light 209 from the image side is blocked by the shutter 202 and does not reach the photoconductor 108. Next, when image exposure is started, the shutter 202 moves in the X'direction in the figure in synchronization with the peripheral speed of the photoconductor 108, and the image exposure slit 203 causes the shutter 2 to move.
It is opened in synchronization with the photoconductor 108 by the first slit 205 of 02, and is stopped in the completely opened state as shown in FIG. 7B. When the trailing edge of the original image is reached, the shutter
202 moves in the X'direction and is gradually closed by the edge of the first slit 205 on the side opposite to the traveling direction, and is completely closed as shown in FIG. , And is returned to the position shown in FIG. The static elimination lamp 115 is turned off by cutting the light of the static elimination lamp 115 with the shutter plate 45, and as shown in FIG. Parts are formed. The position of the shutter 202 is the first position.

Then, as shown in FIG. 7B, the shutter 202
The position of the shutter 202 where the image light path is opened by the first slit 205 serving as an opening, the image light is guided to the photoconductor 108 through the image exposure slit 203 serving as the opening of the light shielding member 201, and the image portion is formed. Is the second position.

Further, as shown in FIG. 7C, the shutter 202 blocks the image optical path, and a non-image portion at the rear end of the image portion is formed.
The position of the shutter 202 is the third position.

Next, in the case of positive-positive, in the state shown in FIG. 7A, the light 210 of the static elimination lamp is transmitted through the reflection mirror 208 to the shutter 202.
The image exposure portion of the photoconductor 108 is irradiated with light through the second slit 206 and the static elimination exposure slit 204 of the light shielding member 201.
Next, when image exposure is started, the shutter 202 moves in the X'direction in synchronism with the peripheral speed of the photoconductor 108, and the shutter 202 and the first slit 205 of the light shielding member 201 and the image exposure slit 203.
The image light 209 is exposed on the photoconductor 108 through. On the other hand, the static elimination light 210 from the static elimination lamp starts vignetting by the edge of the second slit 206 opposite to the X'direction. Then, as shown in FIG. 7B, the static elimination light 210 is completely blocked, and the image exposure slit 203 is the first slit of the shutter 202.
When it is completely opened by 205, the operation is stopped and image exposure is performed on the photoconductor 108. Next, when the image exposure is completed, the shutter 202 again moves in the X'direction in synchronism with the peripheral speed of the photoconductor 108, and the image light 209 is the edge of the first slit 205 of the shutter 201 opposite to the X'direction. Vignetting begins. At the same time, the static elimination light 210 from the static elimination lamp is the third light provided on the shutter 202.
Irradiation is started through the slit 207 and the static elimination exposure slit 204 provided on the light shielding member 201. The image light 209 is completely blocked by the shutter 202 and the image exposure is completed.
After reaching the state of FIG. 7C, the shutter 202 moves in the opposite direction in the X ′ direction and returns to the state of FIG. 7A. In addition,
As shown in FIG. 7A, the image light path is blocked and the light from the charge eliminating lamp 115 is used as the second opening of the shutter 202.
When the position of the shutter 202 is negative and positive, the non-image portion at the leading end of the image portion is formed by being guided to the photoconductor 108 through the slit 206 for removing the light and the slit 204 for static elimination exposure as the opening of the light shielding member 201. Is the position.

Further, as shown in FIG. 7B, the static elimination lamp 115
The light from is blocked so as not to be guided to the photoconductor 108, the image light path is opened at 205 by the first slit, and the image light is passed through the image exposure slit 203 of the light blocking member 201 to the photoconductor.
The position of the shutter 202, where the image portion is guided to 108,
The second position is the same as in the case of negative-positive. Further, as shown in FIG. 7C, the light from the charge eliminating lamp 115 is blocked by the third slit 207 serving as the opening of the shutter 202. The position of the shutter 202, which is guided to the photoconductor 108 through the static elimination exposure slit 204 of the light shielding member 201 and forms the non-image portion at the rear end of the image portion, is the third position as in the case of the negative-positive.

Although the exposure apparatus of the present invention is applied to the reader printer in this embodiment, the present invention is not limited to the reader printer, but can be applied to an electrophotographic copying machine or the like.

(Effect of the Invention) The present invention has the above-described configuration and operation, and the shutter moves in synchronization with the movement of the photoconductor, and the shutter has the same first position regardless of whether it is a positive original or a negative original. It is characterized in that the front end non-image portion, the image portion, and the rear end non-image portion are formed by taking the second position and the third position.

Thus, it is not necessary to change the operation of the shutter depending on the positive original and the negative original, and the movement of the shutter is synchronized with the movement of the photoconductor, so that the shutter moving mechanism can be extremely simplified.

[Brief description of drawings]

1 is a schematic configuration diagram of a reader printer as an image forming apparatus incorporating an exposure device according to an embodiment of the present invention, FIG. 2 is a plan view of the exposure device of FIG. 1, and FIG. Is the second
FIG. 4 is a schematic front view of the spring clutch portion of the device shown in FIG.
FIG. 5 is an enlarged plan view showing the movable mirror and the vicinity of the guide member of the apparatus shown in FIG. 5, FIG. 5 is a front view of the same portion shown in FIG. 4, and FIGS. 6 (a) to 6 (d) show the shutter during operation shown in FIG. 7A to 7C are operation explanatory views showing the relationship between the slits, and FIGS. 7A to 7C are operation explanatory views showing the relationship between the shutter and the shutter of the exposure apparatus of the reader printer according to the embodiment of the present invention. Is a schematic configuration diagram of a reader printer incorporating a conventional exposure device, and FIG. 9 (a) is a diagram showing exposure amounts in an image portion and a non-image portion on a photoconductor in the case of negative-positive, FIG. B)
FIG. 4 is a diagram showing exposure amounts in an image area and a non-image area on a photoconductor in the case of positive-positive. Explanation of reference numerals 1 ... Shading member 1a ... Slit (opening of shading member) 2 ... Shutter 10 ... Shutter opening 108 ... Photoreceptor 115 ... Static elimination lamp (light source) 201 ... Shading member 203 ... … Slit for image exposure (opening of light shielding member) 204 …… Slit for static elimination exposure (opening of light shielding member) 202 …… Shutter 205 …… First slit (opening of shutter) 206 …… Second slit (Shutter opening) 207 ... Third slit (shutter opening)

Continuation of the front page (56) Reference JP-A-50-33841 (JP, A) JP-A-57-62074 (JP, A) JP-A-60-49361 (JP, A) JP-A-57-26870 (JP , A) JP 56-143467 (JP, A) JP 59-142572 (JP, A) JP 56-132358 (JP, A) Actual development 57-110560 (JP, U) Actual development 57-112350 (JP, U) JP 56-18953 (JP, B2) JP 59-17831 (JP, B2) JP Hei 2-48114 (JP, B2) JP Hei 2-48113 (JP, B2)

Claims (2)

[Claims] 1. An image forming apparatus having a movable photoconductor and a light source for forming a non-image portion on the photoconductor and capable of forming an image on each of a positive document and a negative document. In, a light-shielding member having an opening for transmitting light, and a shutter provided with an opening for transmitting light provided on the upstream side of the light path of the light-shielding member, wherein the light-shielding member is fixed, The shutter moves in the same direction as the moving direction of the photoconductor and at a synchronized speed, and has a first position and a second position aligned in the moving direction.
In the case of a positive original, the light source is turned on, and when the shutter is in the first position, the shutter blocks the image optical path and the light from the light source emits light. When the shutter is in the second position, the light from the light source is not guided to the photoconductor when it is guided to the photoconductor through the openings of the shutter and the light shielding member to form the non-image part at the tip of the image part. And the image light path is opened and the image light is guided to the photoconductor through the opening of the light shielding member to form an image portion. When the shutter is in the third position, the shutter blocks the image light path and the light source Light is guided to the photoconductor through the openings of the shutter and the light shielding member to form a non-image portion at the rear end of the image portion. In the case of a negative original, the light source is turned off and the shutter is set to the first position At one time, the shutter blocks the image light path to form a non-image area at the end of the image area. When the shutter is at the second position, the shutter opens the image light path and exposes the image light through the opening of the light blocking member. An image forming apparatus, characterized in that an image portion is formed on a body, and when the shutter is in the third position, the shutter blocks the image optical path and a non-image portion at the rear end of the image portion is formed. 2. An image forming apparatus having a movable photoconductor and a light source for forming a non-image portion on the photoconductor and capable of forming an image on each of a positive document and a negative document. In, a light-shielding member having an opening for transmitting light, and a shutter provided on the upstream side of the light path of the light-shielding member for transmitting light, the light-shielding member is fixed, The shutter moves in the same direction as the moving direction of the photoconductor and at a synchronized speed, and has a first position and a second position aligned in the moving direction.
, And a third position. A fixed mirror that bends the light from the light source toward the opening is provided at the front edge of the shutter opening in the shutter moving direction, while the shutter opening of the shutter opening is moved in the shutter moving direction. A first mirror position in which a movable mirror is provided at the trailing edge, the movable mirror blocks light from the light source to the fixed mirror and is bent toward the opening, and a second mirror position in which light from the light source passes to the fixed mirror To
In the case of a positive document, the light source is turned on, and when the shutter is in the first position, the fixed mirror of the shutter blocks the image optical path and the movable mirror moves to the first position. As the two-mirror position, the light from the light source is bent by the fixed mirror and guided to the photoconductor through the openings of the shutter and the light shielding member to form the non-image part at the tip of the image part, and the shutter is at the second position. In this case, the light from the light source, which is bent by the fixed mirror and passed through the shutter opening, is blocked by the light blocking member so as not to be guided to the photoconductor, and the image light path is opened so that the image light is blocked by the light blocking member. An image portion is formed by being guided to the photoconductor through the opening, and when the shutter is in the third position, the movable mirror is set as the first mirror position and the image is formed by the movable mirror. The light that has blocked the optical path and is bent by the movable mirror from the light source is guided to the photoconductor through the openings of the shutter and the light shielding member to form the non-image portion at the rear end of the image portion. In this case, the light source is turned off, the movable mirror is set to the second mirror position when the shutter is at the first position, and the image mirror optical path is blocked by the fixed mirror of the shutter to form the non-image part at the tip of the image part. When the shutter is in the second position, the fixed mirror of the shutter opens the image light path and guides the image light to the photoconductor through the opening of the light shielding member to form an image portion, and the shutter is in the third position. An image forming apparatus characterized in that the movable mirror is used as a first mirror position at a certain time to block the image optical path by the movable mirror to form a non-image portion at the rear end of the image portion.