JPS5878171A - Original scanning device - Google Patents

Abstract

PURPOSE:To relieve a shock for a titled device at the time of starting or stopping operation, by providing a projecting device of a fluid pressure such as oil pressure and air pressure at the end of moving paths of an optical scanning bodies being a moving back and forth body and an original base. CONSTITUTION:When optical scanning bodies 4, 7 move back and forth, at the same time of seizure of the forth driving a pump 38 is operated so that an oil in a tank 37 is press-transported into a cylinder or the first device A(1) through a valve 39 in an open state, and thereby a piston rod 32 is moved to project. Then, a pressure in a forth moving direction is applied to a rail sliding block 271 of the first mirror supporting base 27 through a lever 35 by the projection of the piston rod 32, and as the result, a positive pressing force becomes an auxiliary initial driving force and even if the optical scanning bodies 4, 7 receive a rapid accelerating force from a driving mechanism owing to the high speed driving, the generation of shock at the starting time on the basis of static inertia is relieved and the oscillation and noise owing to the shock at the starting time are greatly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document scanning device in an image forming device such as a copying machine, and relates to a reciprocating optical scanner, a reciprocating document platen, and the like, which are the main components of the device. The purpose is to reduce as much as possible the shock during starting and stopping at the end of movement, and to suppress mechanical vibrations and noise caused by shocks and bumps.

For convenience, FIG. 1 shows a very schematic structure of a scanning body portion of an example of an optical scanning body reciprocating type copying machine, and a detailed description will be given below based on this. Namely, 1 is a drum-shaped photoreceptor (hereinafter simply referred to as a drum) which is driven to rotate at a peripheral speed V in the direction of the arrow with the axis 2 as the center; A document mounting table made of a transparent plate such as a glass plate (hereinafter simply referred to as a document table), 4 is a movable first scanner as an optical scanner for the document surface disposed below the document table 3, and is normally placed on the left side of the document table. The actual binding position is set as the home position and is on standby, and in response to the copy start signal, the document table is guided by the right side of the document table (rail 5-5 (Fig. 2) along the bottom surface of the document table and reciprocated at a speed of V). When it is driven a and reaches the end point of the forward movement of the dashed line water, it is turned into a backward drive bK and returns to the initial home position on the left side of the document table and waits.

6.6 reciprocates together with the above-mentioned moving first electric roller 4,
A document illumination lamp with its light exit facing upward, 7 is a movable second mirror that receives the reflected light from the first movable mirror 4, and like the first movable mirror 4, it is always positioned at the solid line water position on the left side of the document platen. 9 is on standby as the home position, and in conjunction with the forward movement 8 of the first mirror 4, it is guided by the rails 5 and 5 and is driven forward at a speed V/2, which is half the speed of the first mirror 40. When the robot moves back, it moves back and returns to its initial home position and waits. 8 is an imaging lens, 9.
10 is a fixed third and fourth mirror.

Dora J! Various image forming process execution units according to any conventionally known image forming process are arranged around 1, but are omitted from the drawing.

The original O is placed on the upper surface of the original table 3 with the side to be copied facing downward, and the original pressing plate 11 is placed over it and set immovably. Then, in response to the copy start signal, the document illumination lamps 6, 6 are turned on for the optical scanning body mechanism, and the speed K, the speed of the first movable electric mirror, and the speed V of the second movable mirror are turned on.
Forward drive a at /2 is started. Due to the forward movement of the optical scanning body, the downward facing document on the original scanning table 3 is moved forward through the lamps 6 and 6 through the transparent document table 3 in both transverse directions of the document substantially perpendicular to the moving direction of the lamp 6 and the moving direction of the lamp 6. The illumination line is scanned sequentially from the left side of the document to the right side, and the reflected light from the document surface is sequentially incident on the moving 1111 mirror, which is moving forward, and the reflected light is moved. t1g2 mirror 7 → imaging lens 8 → fixed 30th fourth mirror 9.1
Image formation exposure (slit exposure) is performed directly through the slit 12 on the drum 1 which is rotating at a circumferential speed V via the center of the drum 1, and copying is performed. In this case, the second moving mirror 7 moves forward at a speed of V/2 relative to the forward movement of the first moving mirror 4 at a speed of V, so that in the scanning process from the left side to the right side of the document surface. At each time point, the original page 0 → Movement 1st page 4 → Movement II 2
The optical path length from the mirror 7 to the imaging lens 8t is always kept constant. A slit image of the original light is exposed to a slit image without being out of focus from beginning to end on one surface of the thin film.

When the moving first roller 4 and the second moving roller 7 reach the end point of the forward movement of the dashed line water, they are turned into a backward movement, and return to the initial home position on the left side and wait. During this return movement process, the document illumination lamp is kept off. This backward movement speed is generally set to be faster than the forward movement speed in order to shorten one copying cycle time as much as possible.

The reciprocating drive of the first and second mirrors 4 and 7 is generally performed by a tension wire type as shown in the second figure.

That is, a drive shaft 13 is rotationally driven in the arrow direction by a force source not shown in the figure, and the rotational force is transmitted to the drum gear 15 via the gear 14, so that the drum 1 is rotationally driven in the arrow direction at a circumferential speed V. Reference numeral 16 denotes an electromagnetic clutch attached to the drive shaft 13. When the clutch is energized, the gear 17 of the clutch rotates together with the drive shaft 13, and when it is deenergized, the gear 17 is rotated.
7 and the shaft 13 are not engaged, and the gear 17 becomes free to rotate relative to the shaft 13. 18 is a gear meshed with the clutch gear 17, 19 is a drum on which the wire is wound integrally with the gear, and 20 is a double pulley (moving pulley) attached to the 25th roller support base 21 via a plate 22. ) 23 and 24 are fixed pulleys arranged on both ends of the rail 5, 25 and 26 are fixed boots arranged on the left and right sides of the drum 19 for wire winding, and W is a wire with one end W1 is firmly locked against the fixed member, and the wire is wound on the drum 19 (several turns → pulley 25 → pulley 23).
→Hang it along the same path 20, and lock the other end W2 to the fixed member and υ. Further, the suspended wire W is connected and fixed to the first mirror support base 27 with a stopper 28. kg is a spring that constantly tensions and urges the second zler support base 21 toward the forward movement start end.

Then, when the electromagnetic clutch is energized, gears 17 and 1
8 rotates the drum 19 in the direction of the arrow, and the accompanying tension of the wire W causes the first roller support 27 and the second roller support 21 to move along the rail 5, respectively. At a speed ratio of V/2, the tension spring 29 is stretched and driven forward against the tension spring 29. That is, the forward movement a of the first and second rollers 4 and 7 is activated. When the mirrors 4 and 7 reach the forward end, the electromagnetic clutch 16 is demagnetized and the clutch gear 17 is disconnected from the drive shaft 13.
This time, the first and second mirror supports 27 and 21, that is, the first and second mirrors 4 and 7, are driven backward by the tensile force of the tension spring 29 and are pulled back to the initial home position.

By the way, in the above example, when the first and second mirrors 4e7 (including the support bases 27 and 21° pulleys 20), which are reciprocating optical scanning bodies, are driven forward a, the optical scanning bodies 4 and 7 are moved at the time of activation. A shock phenomenon occurs due to the static inertia of the engine (start-up shock). Further, the active drive of the optical scanning bodies 4 and 7 by the drive mechanism is cut off a little before reaching the end of the forward movement, but since they continue to coast, even when the coasting is stopped by the stopper member, a shock phenomenon occurs and the process is stopped. shock when stopping). The above-mentioned start-up shock and stop-shock reach the end of the forward movement and stop once, and the nine optical scanning bodies 4 and 7 start the backward movement by the force of the tension spring 29 and return to the forward movement starting point, that is, the home position. It also occurs when it stops returning to nine.

The above-mentioned shock at the time of starting and stopping occurs as the mass of the optical scanning bodies 4 and 7 increases, and as the reciprocating speed of the optical scanning bodies 4 and 7 increases to speed up processing such as copying as much as possible, the more rapid the acceleration and deceleration becomes. It will become something big. The shock causes vibration and noise.

This has a considerable adverse effect on image formation, etc.

Therefore, in the past, in order to mainly alleviate the shock when stopping, an elastic buffer such as a spring was placed at the end of the moving path of the optical scanning body to absorb the shock, and the driving wire feeding pulley of the optical scanning body was oscillated. Although measures such as absorbing the movement inertia of the optical scanning body by moving the optical scanning body have been adopted, it is not sufficient, and the mass of the optical scanning body is large, making it difficult to put it into practical use if it is driven at high speed. I can't offer it.

The same thing can be said about the document table of a reciprocating document table type copying machine, an information reading device, or the like.

The present invention was proposed in view of the above-mentioned problems.
Even when the moving body is driven at high speed, the shock at the time of starting and stopping the moving body is greatly and effectively alleviated with as short a run-up or overrunning length as possible, so that the moving body can start and stop smoothly.

That is, a hydraulic protrusion device such as hydraulic pressure or pneumatic pressure is provided at the end of the movement path of the optical scanning body or document table, which is a reciprocating body, and the protrusion of the device is moved to protrude when the movable body starts moving. The protrusion directly or through another member pushes the moving body to apply a starting assisting force to the moving body, and when the moving body is stopped, the protrusion is applied to the moving body that still has moving force. Each time it is received directly or through another member by the protrusion of the above-mentioned device, which is in a protruding state, and when a retraction force is applied to the protrusion, the internal fluid is gradually removed while resisting the retraction force. The gist of the present invention is a document scanning device in which a moving body is braked and brought to a stop by the damper action of a displacement device.

In the example shown in FIG. 2, hydraulic cylinder piston devices A@A are protruded as fluid pressure protrusion devices near both ends of the reciprocating guide rail 50 of the optical scanning bodies 4 and 7, that is, at the forward movement start end and the forward movement end. A child piston rod 32 is fixedly disposed toward the optical scanning body. Hereinafter, for convenience, the device at the forward movement start end side will be referred to as the first device Aω, and the device at the forward movement end side will be referred to as the second device Aω.

In addition, a lever 35 is provided in front of the end of the piston rod of each of the device members (1) and A(2), and is rotatable about a shaft 34.
The lever 35 is biased to rotate in the direction of the piston/rod end by a pull spring 36, so that the substantially central part of the lever is always kept in contact with the surface of the piston rod tip end seat 33. This lever 35 serves as a contact for the rail slide block 271 of the first mirror support stand 27.

Both of the above devices A(1) and A@ are as shown in the third diagram.

This is an oil supply system that pumps the oil in the tank 37 into the cylinder 30 of each device A(1)-A@ from a common oil supply source consisting of an oil tank 37 and a pump 38 via pulps 39 and 40, respectively. That is, when the pump 38 is operated and the pulp 39 is opened in good condition, the piston/rod 32 of the first device A (1) is opened, and when the pulp 40 is opened, the second device (A) (2
) the piston rod 32 moves outward.

(1) Mitigation of starting shock at forward movement start point When the optical scanning bodies 4 and 7 are waiting at the home position before the forward movement starts, the pump 38 is held in the inactive state and the pulp 39 is held in the open state, and the first device The piston rod 32 of A(1) is in a sufficiently retracted state within the cylinder 30, and the optical scanning body 4-7 is pulled toward the first device A(1) by the tension spring 29 and moves to the first device A(1).
The rail slide block 271 of the rail support stand 27 is
It is received by the tip of the lever 35, which is still in contact with and received by the piston rod tip receiving seat 33 of the device A (1), and is held in a standby state at the home position (Fig. 3a). ). On the other hand, on the second device side, the pulp 40 is closed, but the cylinder 3o is filled with oil and the piston rod 32 is held in a protruding state.

When the optical scanning bodies 4 and 7 move forward, the pump fm is operated at the same time as the start of the forward movement, and the oil in the tank 37 is pumped through the open pulp 39 to the first device A (1). By force feeding into the cylinder 3o, the piston rod 32 is moved to protrude. Then, due to the protrusion of the piston rod 32, a pressing force in the forward direction acts on the rail slide block 271 of the first electric power support stand 27 via the lever 35. As a result, the active pressing force becomes a starting assist force, and the optical scanning bodies 4 and 7 have a large mass. The occurrence of shock is effectively alleviated, the optical scanning bodies 4 and 7 move forward smoothly, and the vibration and noise caused by the shock at the time of startup are significantly reduced.

(To) Alleviation of stop shock at the end point of forward movement When the optical scanning bodies 4 and 7 start forward movement, before they reach the end point of forward movement,
The pulp 39 on the first device A(1) side is changed from the open state to the closed state, and the pump 38 is made inactive. [1 device A
11 of the piston rods 32 of α) are held in the protruding state. On the other hand, /'(hp 40 on the second device @ side is changed from the closed state to the open state.Even if this pulp 40 is opened, the pattern 2*tA(2)II.
The yoke J'' exists in the cylinder 30, and the protruding state of the piston rod 32 is maintained as it is.

When the optical scanning bodies 4 and 7 move forward and reach the #I2 device A (1) side, the active forward drive by the drive mechanism is cut off a little before 2, but the optical scanning bodies 4 and 7 continue to be driven by inertia. Move the rail slide block 271 of the first mirror support 27
hits the tip of the lever 35 on the second device A(2) side. Therefore, a retraction force acts on the piston rod 32 via the lever 35, and the skeleton piston rod pushes the filled oil in the cylinder 30 back to the oil tank 37 through the path of the pulp 40 in the open state and the pump 38 in the inactive state. Go back to work against push-out resistance. The optical scanning bodies 4 and 7, which are moving by rounding and inertia, are decelerated and come to a stop due to the damper effect of the piston rod 32, which moves backward against the oil extrusion resistance. Figure 3 b). By appropriately controlling the oil return flow rate relative to the pressing force by adjusting the opening degree of the hydraulic valve 40, intervening an orifice in the oil passage, etc., even if the moving inertia is large, the overrunning length is short and effective. By absorbing movement energy, the optical scanning bodies 4 and 7, which are moving moving bodies, can be decelerated and stopped with low shock.

(3) Mitigating the starting shock at the start point of the backward movement When the optical scanning bodies 4 and 7 once stop at the end point of the forward movement (= the start point of the backward movement), they are thinned out in the forward movement and are stretched by the tension hook of the nine tension springs 29. Okay, now it turns to double action, and the pressure pump 38 is operated to force oil into the cylinder 3o of the second device A (2) through the pulp 40 in the open state. Then, the piston rod 32 protrudes, and a pressing force in the backward movement direction acts on the rail slide block 271 of the first mirror support stand 27 via the lever 34. As a result, as in the case of the forward movement start point in (1) above, the positive pressing force becomes a starting assist force, and the optical scanning body 4-7 has a large mass or is subjected to sudden acceleration due to a strong spring force. Based on static inertia, the occurrence of shock at startup is effectively alleviated, and the optical scanning bodies 4 and 7 are smoothly started backwards.

(4) Mitigating the stop shock at the end point of the backward movement When the optical scanning bodies 4 and 7 start the backward movement, the valve on the front K11i2 device A (2) side that ends at the end point of the backward movement (=the starting point of the forward movement) 40 converts from the open state to the closed state.

Pump 3B is made inactive. The piston rod 32 of the second device A(2) is maintained in its 11 protruding state. On the other hand, the oil in the cylinder on the first device A (2) side is actively removed even if the valve 39 on the first device A (1) side is changed from the closed state to the open state. The nine piston rods 32 remain in the cylinder 30 without being released.
The protruding state of is maintained as it is.

When the optical scanning body 4117 moves backward by the restoring force of the spring 29 and reaches the first device person (1) side, the first mirror support stand 27
The rail slide block 271 hits the tip of the lever 35 on the first device A(1) side. Therefore, a retraction force acts on the piston rod 32 via the starvation lever 35, and the piston rod opens the valve 3 with the full oil in the cylinder 30 open.
9. The oil is pushed back to the oil tank 37 through the path of the inactive pump 38, and the oil is returned to work against the oil pushing resistance. Therefore, (2) the scanning bodies 4 and 7 are decelerated and stopped due to the damper effect of the piston rod 32, which moves backward against the oil extrusion resistance, as the moving energy is absorbed as an oil extrusion force. In this case as well, by adjusting the opening degree of the valve 39, orifice intervention in the oil passage, etc., the oil return flow rate can be adjusted appropriately to the pressing force, so that even if the movement inertia is large, the movement energy can be effectively saved with a short overrunning length. By absorbing the shock, the optical scanning bodies 4 and 7, which are moving moving bodies, can be decelerated and brought to a stop with a low shock.

Opening and closing of the valves 39 and 40 as in (1) to (4) above,
Activation/deactivation of the pump 38 may be controlled automatically in relation to the reciprocating drive of the optical scanning body.

That is, the optical scanning body, which is a reciprocating body, has a large mass υ1. Even if the scanning body is driven at high speed, it can be easily stopped due to the inertia and transferability of the scanning body, and the shock at startup and stop can be greatly alleviated with the shortest possible run-up or overrunning length, making it smooth. It can be started and stopped at any time, and the intended purpose is well achieved.

The above explanation was given using a reciprocating type of optical scanning body as an example.
It goes without saying that similar effects can be obtained by employing a similar device configuration for a reciprocating document table type.

[Brief explanation of drawings]

Fig. 1 is a very schematic configuration diagram of the optical system part of an example of an optical scanning body reciprocating copying machine, Fig. 2 is a perspective view of the optical system drive mechanism part, and Fig. 3 avb is an explanatory diagram of the operation of the shock mitigation device. . 1 is a photosensitive drum, 3 is a document mounting table, 4/7Fi moving first and second mirrors as a moving optical scanning body, A(1)/A
(2) K is a shock mitigation device.

Claims (1)

[Claims] In a document scanning device, a fluid pressure protrusion device is provided at the end of the movement path of an optical scanning body or a document table, which is a reciprocating body, and when the movable body starts moving, the protrusion of the device is moved to protrude. The protrusion pushes the moving body directly or through another force to apply a starting assisting force to the moving body, and when the moving body stops, the protrusion removes the moving body that still has moving force. is in a protruding state, and when a retracting force is applied to the protrusion, the internal fluid is gradually removed while resisting the retracting force. K] A document scanning device in which the moving body was braked and brought to a stop by repairing the device's damper.