JP2511458B2 - Variable power drive controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable power drive control device in a variable power copying machine.

(Prior Art) Some electrophotographic copying machines are provided with a variable power mechanism. As a variable power mechanism, there is a system in which a lens is arranged in the optical path between a document and a photoconductor, and the position of the lens is moved to perform variable power. In this method, the mirror length in the optical path is also moved in order to correct the conjugate length accompanying the lens movement.

In such a variable power mechanism, the lens is driven through a gear in a stepping mode.

Conventionally, in order to eliminate an error due to gear backlash, the lens stop direction is set to one direction (Japanese Patent Laid-Open No. Sho 60).
-156052). However, this method has a problem of focus shift due to movement of the mirror for correcting the conjugate length.

When the stop direction of the lens is set to one direction, the moving direction of the mirror for correcting the conjugate length is two directions. By the way, this mirror is an elongated mirror, and when the lens / mirror drive system is configured by a single drive source in the conventional example, the mirror is unavoidably supported at one end side in the longitudinal direction of the mirror due to the configuration of the drive system. There is no choice but to use a one-sided waiting structure. In such a drive system, when the lens is driven to vary its magnification, the movement of the mirror when the mirror is not driven is slightly delayed due to an obstacle or the like, the mirror surface is tilted, and the focus is deviated. One-sided blurring occurs. Moreover, since this deviation does not occur in a fixed direction, it is not possible to adjust for the deviation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable power drive control device in a variable power copying machine in which no shift in focus occurs due to movement of a conjugate length correcting mirror.

(Means for Solving Problems) A variable magnification drive control device according to the present invention includes a variable magnification lens means arranged in an optical path between an original and a photoconductor, and an optical path between the original and the photoconductor. In a copying machine provided with a mirror means for correcting the conjugate length, the mirror moving means for supporting and driving the above-mentioned mirror means on one side in the longitudinal direction for the conjugate length correction, and the conjugate length correction for the above-mentioned mirror means. And a mirror movement control means for controlling the mirror movement means so as to keep the stop direction of the mirror means constant during the movement.

(Operation) The movement stop direction of the correction mirror is always constant. This makes the error due to the stop of the mirror constant.

(Examples) Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a sectional view schematically showing the structure of the copying machine (10). First, the structure and operation of the copying machine (10) will be briefly described with reference to this figure. At the center of the main body of the copying machine (10), there is a photosensitive drum (1
1) is arranged around the main eraser lamp (12), sub-charger (13), sub-eraser lamp (14), main charger (15), developing device (1).
6), a transfer charger (17), a copy paper separation charger (18), and a blade type cleaning device (19) are sequentially arranged. The photoconductor drum (11) is provided with a photoconductor layer on its surface, and the photoconductor is made uniform by passing through the eraser lamps (12), (14) and the chargers (13), (15). Scanning optical system (20) after being charged
Receive image exposure from.

The scanning optical system (20) is installed below the original glass so that the original image can be scanned, and includes a light source (27), movable mirrors (21), (22) and (23), and a lens (24). , A movable mirror (25).

During scanning, the light source (27) and the movable mirror (21) are
The peripheral speed (V) of the photoconductor drum (11) (constant regardless of equal magnification or variable magnification) is scanned to the left at a speed of (V / m) (however, m: copy magnification), and the movable mirror is moved. (22) and (23) are driven by a DC motor (M1) so as to move leftward at a speed of (V / 2m).

On the other hand, on the left side of the main body of the copying machine, paper feed cassettes (30) and (31) equipped with paper feed rollers (32) and (33), respectively.
However, it is installed detachably. The copy paper conveyance path is composed of roller pairs (34) and (35), a timing roller pair (36), a conveyance belt (37), a fixing device (38), and a discharge roller pair (39).

In the above configuration, the main drive system including the photosensitive drum (11), the conveyance rollers (34) and (35), the conveyance belt (37), the fixing device (38), etc. is driven by the main motor (M), A periodic motor that rotates at a constant speed depending on the frequency of the AC power source is used as the main motor (M). The scanning optical system (20) is driven by a speed controllable DC motor (M1) and is mechanically independent of the main drive system.

The copy operation is accompanied by the input of the copy start signal.
First, the main motor (M) starts rotating, and the main drive system including the photoconductor drum (11) is driven. At the same time, or with a slight time delay, the clutch of one of the paper feed rollers (32) and (33) is turned on to transmit the drive of the main motor (M) to the paper feed roller to feed the copy paper. At the same time, the eraser lamps (12), (14), chargers (13), (15), etc. are turned on. Further, the exposure lamp (27) is turned on with an appropriate time delay, and the direct current motor (M1) starts rotating at a predetermined speed corresponding to the copy magnification, and the scanning optical system (20) is rotated in the above-described relationship. Move to the left in the figure. Then, the document on the document glass (26) is scanned, and the image is sequentially projected onto the photosensitive drum (11) that is being driven to rotate, so that an electrostatic latent image is formed on the drum surface.

The electrostatic latent image formed on the photoconductor drum (11) is developed by passing through the developing device section (16) as the drum (11) rotates, and further transferred to the transfer charger (17) section. Move to.

On the other hand, the copy paper fed by the paper feed roller (32) or (33) contacts the timing roller (36) and is temporarily stopped. When the timing roller (36) is driven by the timing signal output in synchronization with the image forming operation on the photoconductor drum (11), the timing roller (36) is moved forward again to move the photoconductor drum (11) and the transfer charger (17) to each other. Between the surface of the drum (11) and the developed image on the surface of the drum (11) to receive the image transfer, and then separated from the surface of the drum (11), and the conveying roller (37), the fixing device (38), etc. To the discharge tray (40).

FIG. 3 is a perspective view showing a drive mechanism for the lens (24) and the movable mirror (25). The lens (24) is attached to the lens base (5
Fixed to 1). The lens base (51) has a through hole (51a) through which the shaft (52) passes, and can move along the shaft (52). The home switch (SW) detects that the lens (24) is in the reference position (usually set to the same size). It emits an ON signal when the lens is on the magnification side of the reference position, and otherwise Sends off signal.

The lens stand (51) is driven by a shaft (5
Thread (53) is stretched parallel to 2). The thread (53) is attached to the pulley (5
It is wound around the gear (56) via (4,55). The gear (56) meshes with a gear (57) fixed to the shaft of the stepping motor (M2). When the stepping motor (M2) is rotated, the yarn (53) moves parallel to the shaft (52) by gear transmission, and the lens (24) correspondingly moves in the direction A or B of the shaft (52).

On the other hand, the movable mirror (25) is attached to the mirror support base (61). The mirror support (61) is a movable mirror (2
5) Slide pin (6
2), and slidably supports the slide pin (62) on the first guide rail (63). As a result, one end of the movable mirror (25) in the longitudinal direction of the mirror support base (61) is slide-guided on the first support rail (63).
Further, the mirror support base (61) has two slide pins (63, 64) projecting to the other end side in the longitudinal direction of the movable mirror (25).
Both of the slide pins (63, 64) are fitted in a guide groove (66) provided in the second guide rail (65) and extending in the front-rear direction so that they can be slide-guided. .

In addition, the L-shaped piece (7
1) is attached. This L-shaped piece (71) is supported by the second guide rail (65) via the spring (72),
The spring (72) biases the movable mirror (25) in the backward direction (D). Further, the L-shaped piece (71) is connected to one end of the follower lever (74) via the connecting lever (73) on the side opposite to the spring (72). Follower lever (7
The other end of 4) is swingably supported by a support shaft (74a) in a horizontal plane. Further, the crank lever (74) has a cam follower (75) protruding downward in the middle thereof, and the cam follower (75) is always in contact with the cam (76) by the force of the spring (72). The cam (76) is fixed on the gear (77) so as to rotate integrally with the gear (77), and the gear (77) meshes with the gear (78) coaxial with the gear (56). With the above cam follower mechanism, when the stepping motor (M2) rotates, the cam (76) also rotates, and the follower lever (74) moves the L-shaped piece (71) through the connecting lever (73).
Therefore, the movable mirror (25) is moved in the direction C or D. At this time, the other end of the mirror support base (61) slides on the first guide rail (63). In this case, as will be described later, there occurs a problem that a mechanical rattling or a movement delay due to a resistance force occurs.

Next, the movable mirror (25) to a position that compensates for the change in conjugate length.
The movement will be described.

It is well known that when the focal length f of the lens (24) does not change, the conjugate length L becomes the shortest at unity magnification.
Therefore, the movable mirror (25) is at the most advanced position in the direction of arrow C at the same magnification, and is arranged at the position displaced in the direction of arrow D at other magnifications.

Now, it is assumed that the initial magnification m is changed to a new magnification m '. First, a case where the initial magnification m is on the reduction side will be described with reference to Table 1 and FIGS. 4 (a) to 4 (c). The moving direction of the movable mirror (25) may be three depending on the value of the target magnification m '. When the target magnification m'is on the reduction side of the initial magnification m (a), the lens (24) moves in the direction of the arrow B and the movable mirror (25) moves as shown in FIG. 4 (a). Move in the direction of arrow D. On the other hand, when the target magnification m'is on the enlargement side of the initial magnification m, the lens (2
The target position of 4) is in the direction of arrow A when viewed from the initial position, but the movable mirror (25) moves in two patterns. When the target magnification m'is between the initial magnification m and the same magnification (b), as shown in FIG. 4 (b), the movable mirror (2
5) moves in the direction of arrow C, while on the other hand, if the target magnification m is on the enlargement side of the unity magnification (c), as shown in FIG. 4 (c), move once in the direction of arrow C. After reaching the same size position, it moves in the D direction.

As shown in Table 2, even when the initial magnification m is on the enlargement side, the movement pattern of the movable mirror (25) has three cases (d), (e), and (f) depending on the target magnification m ′. is there.

As described above, the movable mirror (25) may be moved in two directions. The movable mirror (25) uses a stepping motor (M2) to move the cam (76) and lever (7).
3,74) through which the driving force is applied on the E side in the longitudinal direction, the movement on the opposite F side is inevitably delayed due to mechanical rattling and resistance. Therefore, as shown in FIGS. 4A to 4C, the mirror surface is inclined as compared with the correct position (shown by the broken line), which causes one-sided blur. There are two directions of this inclination.

Therefore, the present invention solves this problem by keeping the stop direction of the movable mirror (25) constant and the inclination of the movable mirror constant.

FIG. 5 shows the configuration of a variable power drive control device for moving the lens (24) and the movable mirror (25). The microcomputer (5) is composed of a readable / writable random access memory for storing data for movement control, a read only memory, an 8-bit internal counter, an input / output port and the like.

The reference oscillating circuit (6) gives the microcomputer (5) a fixed frequency for determining the interval of the drive pulse of the stepping motor (M2). The microcomputer (5) internally counts the pulses from the reference oscillating circuit (6), and if a preset value is counted, it changes the drive pulse that sends a signal to the stepping motor control circuit (7), Rotate the stepping motor (M2).
This process is repeated as many times as the movement distance.

FIG. 1 shows a flow of control of the movable mirror (25) by the microcomputer (5). In the microcomputer (5), first, when the power is turned on, internal parameters are initialized in step, and in step, processing for returning the lens (24) system to the home position is performed. Be sure to return the lens (24) system to the home position (actual magnification position). At this time, the movable mirror (25)
Always moves in the direction of arrow C, and is arranged via a cam (76) and levers (73, 74) at a position that satisfies the conjugate length at the same magnification. Then, in step, operation check of other optical systems is performed.

In the step, the data necessary for the actual copying operation is input. This data includes paper size and copy magnification.

Based on this data, when it is determined that the lens (24) system has to perform the zooming operation, the moving distance of the lens (24) is calculated in a step according to the initial magnification m and the target magnification m '. In the subsequent step, operation patterns such as moving direction and speed are calculated, and the stepping motor (M2) is driven in step according to the calculation results to move the lens (24) system.

When the movement is completed, control for making the stopping direction of the movable mirror (25) constant is continuously performed. In the step, it is determined whether the initial magnification is larger or smaller than the normal magnification.
In the step, it is judged whether the target magnification is larger or smaller than the same size. If it is larger, the process proceeds to step (corresponding to Table 1 (c) in this case), and if it is smaller, the process proceeds to step. In the step, the magnitude relationship between the initial magnification and the target magnification is judged,
If the target magnification is larger (corresponding to Table 1 (b)), the movable mirror (25) has moved from the direction of arrow C and is stopped, so the process proceeds to step. Conversely, if it is determined that the target magnification is smaller (corresponding to Table 1 (a)), the arrow D
Since it has stopped after moving in the direction of, the movable mirror (25) is moved toward the reduction side (direction of arrow D) (step) and a distance of NM (step) after the step.
After moving (step), the moving direction is reversed (step) (direction of arrow C), and a distance of NM (step) is returned (step). As a result, the movable mirror (25) has moved from the direction of arrow C and stopped.

On the other hand, when it is determined in step that the target magnification m'is larger than the same magnification (corresponding to Table 1 (c)), the movable mirror (25) moves in the direction of arrow D and is in a stopped state. Therefore, this time, the movable mirror (25) is moved (step) toward the enlargement side (direction of arrow D) by a distance of NM (step), and then the moving direction is reversed (step). Step), and return only the distance for NM (Step,). As a result, the movable mirror (25) similarly moves in the direction of arrow C and then stops.

On the other hand, even if the initial magnification is on the enlargement side (NO in step
Similarly, in the case where m <m ′ in Table 2 is satisfied (YES in step,), the stop direction of the movable mirror (25) is changed by performing the same control as described above. Can be constant.

In the above embodiment, the conjugate length correction mirror is shown between the lens and the photoconductor, but, for example,
In the copy table moving type copying machine, the correction mirror may be provided between the lens and the original.

(Effects of the Invention) Focus shift due to the difference in the zooming movement direction, especially one-sided blurring, is eliminated.

[Brief description of drawings]

FIG. 1 is a flowchart of the movement control of the movable mirror. FIG. 2 is a schematic sectional view of the copying machine. FIG. 3 is a perspective view of a variable magnification driving mechanism for the lens and the movable mirror. 4 (a), (b), and (c) are diagrams showing the movement and the movement delay of the movable mirror, respectively. FIG. 5 is a circuit diagram of the variable power drive control circuit. 5 ... CPU, M2 ... Stepping motor, 11 ... Photoconductor, 24 ... Lens, 25 ... Movable mirror, 61 ... Mirror support, 62, 64, 65 ... Sliding member, 72 ... Spring , 73,74 …… Lever, 75 …… Cam follower, 76 …… Cam.

Claims (1)

(57) [Claims] 1. A copier comprising a lens unit for zooming arranged in an optical path between an original and a photoconductor, and a mirror unit for conjugating length correction arranged in an optical path between an original and a photoconductor. , A mirror moving means for supporting and driving the mirror means on one side in the longitudinal direction for conjugation length correction, and a constant stopping direction of the mirror means at the time of movement for conjugation length correction of the mirror means A variable-magnification drive control device comprising: a mirror movement control means for controlling the mirror movement means.