JPH0262864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to magnification conversion devices. In particular, the present invention relates to a magnification conversion device in a slit exposure optical system using a first mirror and a second mirror that scans an original on a fixed original table at a speed ratio of 1:1/2.

Conventionally, in a slit exposure optical system that scans the first mirror and the second mirror at a speed ratio of 1:1/2, magnification conversion is achieved by changing the relative position between the first mirror and the second mirror. This is known. Specific methods for achieving this are also discussed in Japanese Patent Application Laid-open No. 46-5438 and Publication No. 52-41860.
No., Special Publication No. 51-34731, etc. have been proposed.

However, automatic magnification change operations using these methods require an additional drive source, and even when using other drive forces, a complex power transmission mechanism is required. .

The present invention solves the above-mentioned conventional drawbacks, and controls the change in the distance between the first mirror and the second mirror using a simple mechanism, thereby realizing the distance control necessary for desired magnification conversion.

That is, the present invention includes a document placing table on which a document is placed;
a first mirror means for scanning a document; a first mirror support stand movably supporting the first mirror means; a second mirror means that moves at half the speed of the first mirror means during exposure scanning; a second mirror support base that movably supports the second mirror means; a movable base that moves at half the speed of the first mirror means; a projection lens that projects an original image from the original onto the photoreceptor; A means for moving the mirror support base, a means for moving the movable base at half the speed of the first mirror, and a means for engaging the second mirror and the movable base at different positions corresponding to the magnification conversion. By having a structure that includes a means for engaging the second mirror support base and a moving base and a means for releasing the engagement, the mechanism is extremely simple and does not require a new drive source or complicated power transmission means. This makes it possible to perform desired variable magnification operations.

Hereinafter, specific embodiments of the magnification conversion device of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of the configuration of a slit exposure optical system to which the magnification conversion apparatus of the present invention can be applied. 1 is manuscript O
The document O is placed on the first mirror 3 while being illuminated by the illumination lamp 2.
The object is scanned in the direction of arrow A at a speed v. The illumination lamp 2 may move together with the first mirror, or may be fixed to the main body of the copying machine so as to illuminate the entire document O. The original image reflected by the first mirror 3 is also moved at a speed of 1/2 of that of the first mirror 3 by the arrow A.
It is reflected to the projection lens by the second mirror 4 which moves in the direction. This projection lens is an in-mirror lens 5, and a future original image is projected onto the photosensitive drum D by a fixed mirror 6. The second mirror 4 may be composed of two right-angled mirrors as shown in the second figure of Japanese Patent Publication No. 39-6647. In this case, in a transfer type copying machine, the reflection on the optical path from the original to the photosensitive drum is used. You need to increase or decrease the number of mirrors so that the number of times is an even number. Note that in a direct copying machine that directly forms a copy image on photosensitive paper, it is necessary to use an odd number of reflections. Now, when performing variable magnification exposure, for example, when performing magnification at m (<1), the relative position of the second mirror 4 with respect to the first mirror 3 is shifted to 4' as shown by the broken line, as shown in the figure. The relative positions of the first mirror 3 and the second mirror 4 are moved apart. At this time, the in-mirror lens 5 is also moved to the position shown by the broken line. Even during magnification conversion, the rotational speed of the photosensitive drum D and the scanning movement speed of the first mirror 3 and the second mirror 4 are scanned at a speed of 1/m of the speed at the same magnification. Note that the projection magnification in the rotational direction of the photosensitive drum D is determined by the relationship between the scanning speed of the original O by the first mirror 3 and the rotational speed of the photosensitive drum D. It is also possible to change the rotational speed of the photosensitive drum D according to the magnification while keeping the scanning speed constant. At this time, it is necessary to adjust the charging voltage, etc.

FIG. 2 shows an embodiment of the magnification conversion apparatus of the present invention, and the slit exposure optical system itself is shown as a perspective view seen from the rear in FIG. 1st
In order to scan and move the mirror 3 and the second mirror 4, a drive wire 7 that transmits power from a drive source has one end 8 fixed to the main body of a copying machine, etc., and is connected in two rows on a moving table 10 that is movable back and forth on a rail 9. It goes around one of the pulleys 11 and turns back, then passes through the fixed pulley 12 on the same side as the wire fixed end 8 and reaches the central double direction change pulley 13, and then the wire is attached to the reversible motor RM shaft. After being wrapped around the drive pulley 14 several times, it is again turned by the direction change pulley 13, and then turned by the fixed pulley 15 on the opposite side to the fixed pulley 12, supporting the first mirror 3 and moving on the rail 9. After being fixed 17 to the first mirror support stand 16 that moves back and forth, it reaches the double pulley 11 on the movable stand 10, where it is turned and the other end 18 is attached to the main body part on the opposite side from the fixed end 8. is fixed.

In this way, the first mirror support stand 16 and the moving stand 10
The drive wire 7 always maintains a speed relationship of 1:1/2. On the other hand, the driving force from the drive wire 7 is not directly transmitted to the second mirror support stand 19 that supports the second mirror 4, so that it can move freely. For slit exposure scanning, a coupling mechanism is provided so that the relative positions of the movable table 10 and the second mirror support table 19 are integrally moved at a position corresponding to a desired magnification.

Next, this connection mechanism will be explained.

The movable table 10 is provided with a pin 20, while the second mirror support 19 is provided with a first hook member 21 and a second hook member 22. When performing exposure scanning at the same magnification, the first hook member 21 and pin 2
0 engages with each other, and the movable base 10 and the second mirror support base 1
9 is integrated, and the first mirror 3 and the second mirror 4 are reversible motors at the relative positions indicated by the solid line.
RM allows it to move at a speed ratio of 1:1/2. In order to perform exposure scanning with a reduced magnification, the second mirror 4 is moved to the position 4R indicated by the broken line in the figure, and the pin 20 is connected to the second hook member 22, which is also connected to the movable stage 10 during normal exposure scanning. Second
It reciprocates integrally with the mirror support stand 19 while maintaining a new predetermined relationship.

Moving base 10 and second mirror support base 1 during magnification conversion
The structure of the connection mechanism No. 9 will be explained in detail while explaining its operation.

When converting from the same size copying mode to the reduced copying mode, an empty scan is first performed before entering the exposure scan for reduced copying to convert the relative positional relationship between the first mirror 3 and the second mirror 4 to that for reduced copying. When the drive pulley 14 is rotated in the direction of the arrow a for forward scanning of the optical system, the first mirror support base 16 and the moving base 10 are moved in the direction of the arrow A via the drive wire 7, and the pin 20 and the first hook Due to the engagement of the member 21, the movable table and the second mirror support stand 19 move together in the same direction as the arrow A.

The movement path of the first hook member 21 and the second hook member 22 includes a pin 20 and each hook member 21, 22.
A disengagement means is provided for disengaging the engagement. This engagement release means is for each hook member 21, 2.
The pin 20 is made up of a cam 23 that engages with the pin 20 and a plunger 24 that operates the plunger 24. Upon receiving a release signal, the cam 23 is projected into the passage of each hook member 21, 22, and the pin 20 is engaged with the hook member 21, 22. Release.

When converting from the same-size copy mode to the reduced copy mode, the plunger 24 is not energized during the forward motion of empty scanning, that is, during scanning in the direction of arrow A, and when the plunger 24 enters the backward motion, that is, when the drive pulley 14 moves in the direction of arrow B. The first mirror support stand 16, the second mirror support stand 1
9. After the movable table 10 starts scanning in the direction of arrow B, it is energized and the cam 23 is inserted into the travel path of the first hook member 21 and the second hook member 22.
As the movable base 10 and the second mirror support base 19 move in the direction of arrow B, the second hook member 22 on the side without the pin 20 is lifted upward by the cam 23, and then the first hook member 22 engaged with the pin 20 is lifted up. Member 21 is lifted by cam 23, releasing pin 20. The pin 20 provided on the moving table 10 is moved at a constant speed in the direction of arrow B by the drive wire 7.
The second mirror support stand 19 stops without losing the driving force transmitted from the movable stand 10. The pin 20 advances in the direction of arrow B in the groove 25 in the second mirror support base 19, hits the slope portion 26 of the second hook member 22, pushes up the second hook member 22, and enters the pocket portion 27 of the second hook member 22. At the same time, the second hook member 22 falls and engages with the pin 20 due to its own weight or a biasing force such as a spring (not shown). Thereafter, the pin 20 is attached to the second mirror support stand 19 via the second hook member 22.
is driven in the direction of arrow B, performs a backward motion to a predetermined scanning start position, and upon completion of this idle scanning, magnification conversion is completed. As a result of this empty scanning, the second mirror support stand 19 moves to the position shown by the broken line in FIGS. is started. During this blank scanning, as described above, the in-mirror lens 5 is moved to a predetermined position according to the magnification conversion by a drive source (not shown) that is different from the drive source for mirror scanning. There is no need to turn on the illumination lamp 2 during empty scanning.

Next, the case of converting from the reduced copy mode to the same size copy mode in the opposite case will be explained. Also in this case, a blank scan is performed before the regular exposure scan. At the start of forward scanning of the first mirror support stand 16, the movable stand 10, and the second mirror support stand 19, or after the start, the plunger 24 of the disengagement means is energized, and the cam 23 moves the second hook member 22. Inserted into the movement path.
While scanning in the direction of arrow A, the second hook member 2
2 reaches the cam 23 position, and first the first hook member 21 is pushed up by the cam 23, but this time the pin 20 is not engaged, so the first hook member 21 only moves idle. be. Next, the second hook member 22 engaged with the pin 20 is moved to the cam 23.
is reached and pushed up, releasing the pin 20.
The pin 20 of the movable base 19 moves at a constant speed in the direction of arrow A, but the second mirror support base 19 loses the driving force transmitted from the movable base 19 and stops. Pin 20 is the second
Move in the direction of arrow A in the groove 25 of the mirror support stand 19, reach the position of the first hook member 21, and
The first hook member 21 is pushed up against the slope portion 28 of the hook member 21 and enters the pocket portion 29 of the first hook member 21.
The hook member 21 is loaded with its own weight or with a spring (not shown).
The second mirror support base 19 is driven by the pin 20 in the direction of the arrow A and reaches the reversal position of the blank scan. Next, the reversal operation is started, the drive pulley 14 rotates in the direction of arrow b, the first mirror support stand 16, the second mirror support stand 19, and the moving stand 10 move in the direction of arrow B, and the idle scan ends, etc. Set to double copy mode.

In the embodiment, a pin 20 is provided on the movable base 10 side, and a hook member 21 is provided on the second mirror support base 19 side.
22, but the same function can be achieved even if it is reversed.

In addition, idle scanning for magnification conversion does not necessarily require scanning the entire scannable stroke; instead, it is necessary to select the position of the disengagement means, provide two disengagement means, or convert from the same magnification mode to the reduction mode. It is possible to reduce the scanning distance to the minimum required by changing the scanning distance for converting from the reduced mode to the same magnification mode, etc.

FIG. 3 explains a coupling mechanism for switching the relative positions of the first mirror 3 and the second mirror 4 in three stages.

In the figure, the components other than the coupling mechanism are the same as those in FIG. 2, so the same reference numerals are given and the explanation will be omitted. The movable table 10 is provided with a pin 20 as in FIG. 2. On the other hand, the second mirror support base 19 is provided with a first hook member 30 for a first magnification, a second hook member 31 for a second magnification, and a third hook member 32 for a third magnification. Each hook member is individually provided with first to third disengagement means fixed to the second mirror support. The engagement release means has the same structure as that shown in the second figure, but only the cam portion thereof is shown in FIG. They are a first cam 33, a second cam 34, and a third cam 35.

Next, the operation of connecting the movable table 10 and the second mirror support stand 19 at the time of magnification conversion will be explained.

Now, when converting from the first magnification when the pin 20 engages with the first hook member 30 to the second magnification when the pin 20 engages with the second hook member 31, either of the cams must be activated during the forward movement of the idle scan. At the time of return movement, only the first cam 33 is operated, and the pin 20 is moved to the first hook member 3.
0, the movement of the second mirror support stand 19 is stopped, and the second hook member 31 is moved by the movement of the moving stand 10.
engage with. As a result, the movable table 10 and the second mirror support stand 19 are integrated. Magnification conversion is performed so that exposure scanning at the second magnification is performed upon completion of this idle scanning.

From the first magnification, the pin 20 is attached to the third hook member 32.
When converting to the third magnification that engages the pin 20, none of the cams is operated during the forward movement of the idle scan, and the first cam 33 and the second cam 34 are operated during the backward movement to move the pin 20 to the first hook member. 30 to stop the movement of the second mirror support stand 19, and the movement of the movable stand 10 causes it to engage with the third hook member 32. As a result, the movable table 10 and the second mirror support stand 19 are integrated. Upon completion of this blank scan, the magnification is converted to the third magnification.

When converting from the second magnification to the first magnification,
During forward movement during idle scanning, only the second cam 34 is actuated and the pin 2
0 and the second hook member 31 are disengaged and engaged with the first hook member 30 to convert the magnification to the first magnification.

When converting from the second magnification to the third magnification,
During the forward movement of the idle scan, neither cam is operated, and only the second cam 34 is operated during the forward movement to engage the pin 20 and the third hook member 32, thereby converting the magnification to the third magnification.

When converting from the third magnification to the first magnification,
The third cam 35 and the second cam 34 are operated with respect to the third hook member 32 and the second hook member 31 during the forward movement of the idle scan, and the pin 20 is engaged with the first hook member 30. The magnification is converted to the first magnification without operating the cam.

When converting from the third magnification to the second magnification,
During the forward movement of idle scanning, only the third cam 35 is operated to engage the pin 20 with the second hook member 31, and during the backward movement, neither cam is operated and the magnification is converted to the second magnification.

As described in detail above, in the present invention, the magnification can be changed very easily by adjusting the connection position of the movable table 10 and the second mirror support stand 19. This has the advantage of not requiring a new driving source.

It goes without saying that the projection lens is moved by appropriate means to a position corresponding to each magnification conversion.

Furthermore, the present invention is not limited to the embodiments, but can also be realized in the following embodiments.

In the case of the second illustrated example, two disengagement means are provided,
When converting from the same magnification mode to the reduced mode, the engagement of the first hook member is released at the reversal position of the idle scan, and when converting from the reduced mode to the equal magnification mode, the engagement of the first hook member is released. The function is divided into one for disengaging the second hook member before starting. In this case, the stationary inertia of the second mirror support ensures more secure engagement of the pin with the new hook member.

The number of rails may be two, and the first mirror support stand 16 may be mounted on one rail, and the moving stand 10 and the second mirror support stand 19 may be mounted on the other rail.

In this case, the rail support interval of the first mirror support stand 16 can be increased, and the second mirror support stand 19 can also be made smaller, resulting in a smaller device.

As shown in FIG. 4, a short rail 36 may be provided on the second mirror support base 19, and the movable base 10 may be configured to move on the rail. Alternatively, a short rail may be provided on the pulley stand, and the second mirror stand may be moved on the rail.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a slit exposure optical system to which the magnification converting device of the present invention is applied, and FIGS. 2 to 4 show each embodiment of the magnification converting device of the present invention. In the figure, 1 is a document glass, 2 is an illumination lamp, 3 is a first mirror, 4 is a second mirror, 5 is an in-mirror lens, 6 is a fixed mirror, 7 is a drive wire, 9 is a rail, 10 is a moving table, 11 is a double pulley, 12, 13, and 15 are fixed pulleys, 14 is a drive pulley, 16 is a first mirror support stand, 17 is a fixing member, 19 is a second mirror support stand, 20 is a pin, and 21 and 22 are hooks. Member 23 is a cam, 24
25 is a plunger, and 25 is a groove.

Claims (1)

[Claims] 1. First and second mirror means that move to scan a document, and 1/2 of the moving speed of the first mirror means.
a moving member that moves at a speed of
and changing the relative position of the first mirror means and the second mirror means according to a change in magnification, the scanning optical device comprising: an engaging means for engaging the second mirror means and the moving member. However, when the engagement of this engagement means is released in response to a change in magnification, the engagement position between the movable member and the second mirror means is changed by the drive means, so that the engagement of the second mirror means with respect to the second mirror means is changed. The relative position of the first mirror means can be changed, and when the engaging means is engaged, the second mirror means is moved by the driving means at a speed that is half the moving speed of the first mirror means. A scanning optical device characterized in that it is capable of scanning a document.