JPS62262847A - Original reader provided with movable original platen - Google Patents

Abstract

PURPOSE:To smoothly move the titled reader while keeping high position accuracy, by using an inner rail and an outer rail, and a slide rail having a low- frictional resistance material layer between said rails as supporting guide rails for placing an original, and holding a sliding part of the inner rail by a sliding part of the outer rail. CONSTITUTION:An inner rail 1 and an outer rail 10 are constituted by bending a slender metallic plate. As for the inner rail 1, both side end parts 3 of a plane-shaped fitting plate 2 used for fitting it to the main body of a copying machine are bent, and also, its end side is bent to the inside and a projecting guide part 4 is constituted. On the other hand,the outer rail 10 which has been provided so as to cover partially the inner rail 1 from the upper part constitutes a plane-shaped fitting plate 11 used for fitting it to an original platen 39, and recessed guide part 12 which has been bent in accordance with the projecting guide part 4. Also, a low-frictional resistance material layer 13 by a synthetic resin-covered layer is provided on the recessed guide part 12 of the outer rail 10 opposed to the projecting guide part 4 of the inner rail 1.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a document reading device that exposes a document image on a moving document table to a photoreceptor and reads the document image. It is effective for application to image scanners, etc.

(Prior Art) Taking an electrophotographic copying machine as an example of a document reading device, a slide rail is used to support and guide a document table that moves relative to the main body.

FIG. 9 shows a sectional view of a conventional slide rail of this type. This slide rail has an outer rail 20 that is attached to the original table with screws or the like, and an inner rail 22 that is also attached to the main unit using screws or the like. The outer rail 20 has a bent portion 21 at both ends, and a raceway groove 24 is formed inside the portion 21 . One inner rail 22 is arranged inside the outer rail 20,
It has a bent portion 23, the outer side of which constitutes a raceway groove 25 facing the raceway groove 24. A plurality of steel balls 26 held by a retainer 27 are arranged between the raceway grooves 24 and 25.

(Problems to be Solved by the Invention) In the slide rail, the outer rail 20 and the inner rail 22 are moved relative to each other by rolling of the steel balls 26 in the raceway grooves. Therefore, the coefficient of friction caused by the movement of both rails 20 and 22 is extremely small, and they are easily affected by vibrations and inertia caused by movement. This tends to cause variations in speed and excessive movement. This may cause disturbances in the image formed on the photoreceptor and may cause collisions with the main unit.

Furthermore, in order to make the movement of the outer rail 20 smooth, the steel balls are coated with grease, so foreign substances such as dust tend to adhere to them.
The document may be soiled or the grease may solidify, which may impede the smooth movement described above. In addition, some models have steel balls that slide within the raceway grooves at the moving end without rotating, and with this type of structure, once the sliding effect of the grease disappears, the load on the drive source is increased. In the worst case scenario, you may end up stopping the document table in the middle of scanning.

The present invention aims to solve the above-mentioned conventional problems.

(Means for Solving the Problems) The document reading device of the present invention that solves the above problems has the following features:
) a transparent support plate on which a document is placed; (b) a rail that guides the movement of this support plate relative to the main body of the document reading device; concave guide portions on both sides extending in the longitudinal direction; an actor rail having a connecting portion that connects along the direction; an inner rail having a convex guide corresponding to the concave guide portion of the outer rail; and an actor rail provided on a sliding portion of at least one of the inner rail and the outer rail. a slide rail comprising a low friction resistance material layer, one of the rails being attached to the device body and the other rail being attached to the support side; (e) a drive source for the support plate; and (d) the drive source. (e) means for regulating the movement range of the rail; a slit opening perpendicular to the direction of movement of the document; and a light source for illuminating the document; and an optical system including an imaging lens for focusing an original image passing through the aperture onto a photoreceptor.

(Function) In the document reading device of the present invention, the document mounting table is supported by one of the inner rail or the outer rail that constitutes the slide rail and moves relative to the main body device.

As a result, the main unit and the original table have an appropriate amount of sliding resistance due to the presence of the low-friction resistance material layer between both rails, so that the main unit and the original table can slide smoothly over the entire range of movement without generating excessive inertial force. Since there is no reason to change the resistance, it is possible to form a high quality image on the photoreceptor.

(Embodiment) FIG. 1 is an explanatory diagram of the main parts of an electrophotographic copying machine showing an embodiment of an image reading device to which the present invention is applied.

In the figure, a document mounting table 30 using a transparent plate such as glass
moves in the direction of the arrow, and the document 31 above it moves in the direction of the arrow.
The document image is illuminated by a short focus element array lens 33 on a tram-shaped electrophotographic photoreceptor 35 rotating in the direction of the arrow.

A short-circumference image forming means is arranged around the photoreceptor 35 or omitted. As shown in FIGS. 1 and 2, the document mounting table 30 is moved by a rack gear 37 fixed to the body 36 by a motor M which is a drive source on the main unit side. This is achieved by reciprocating rotation of the driven binion float 38. The document table 39, which is composed of an integral structure of a one-piece document placing plate 30 and a take-out body 36, includes the slide rail 10 on the gear side and the end of the placing plate 30 on the opposite side of the slide rail. It is supported by a fixed rail 40 that supports the section, and reciprocates left and right with respect to the exposure position A shown in the first diagram.

Incidentally, in the reading device of the present invention, it is the slide rail 1o that supports the document table 40 and regulates its movement direction. This slide rail consists of an inner rail 1 fixed to the main device side, an outer rail 10 fixed to the handle body 36, and a low friction resistance provided on the surface where this outer rail 1° slides with the inner 1 knob 1. It is composed of a material bonding layer.

Here, the slide rail will be explained.

FIG. 3 is a perspective view of the slide rail of the present invention, FIG. 4 is a side view, and FIGS. 5 and 6 are sectional views. As shown in FIGS. 3 to 6, the inner rail 1 and the outer rail 10 are constructed by bending elongated metal plates. The inner rail 1 is attached to the main body of the copying machine and is mounted in a plane shape by bending the ends 3 on both sides of the plays 1 and 2. It constitutes part 4. That is, the convex kite portions 4 on both sides are connected in the longitudinal direction by the connecting portion of the plate 2.

On the other hand, the outer rail 1°, which is disposed so as to partially wrap around the inner rail 1 from above, is attached to the document table 39.
The planar mounting used for mounting on plate 11
This constitutes a concave guide portion 12 that is bent in correspondence with the convex guide portion 4 .

The concave guide portion 12 of the outer rail 10 facing the convex guide portion 4 of the inner rail 1 is provided with a low friction resistance material layer 13 made of a synthetic resin coating layer. The appropriate layer 13 is as follows:
The resin may be either thermosetting or thermoplastic, such as polytetrafluoroethylene, silicone resin,
Blends of various polymeric substances such as polytetrafluoroethylene, chlorotrifluoroethylene resin, and tetrafluoroethylene-hexafluoropropylene copolymer may be mentioned.

Furthermore, in order to improve the sliding properties of both rails, it is effective to mix these resins with a well-known material that enhances lubricity. It is also effective to bake coat these resin layers in order to increase their durability.

Since the inner rail 1 and the outer rail 10 that move relative to each other in this way are in contact with the low friction resistance material layer 13 and the metal surface, the +91 coefficient is small and a moderate movement resistance is generated against the relative movement of both rails. Even if a large inertial force is generated during movement, it is possible to absorb that force.

Next, a structure for increasing the durability of the layer 13 provided on the first rail will be described.

Since both rails 10 move relative to each other, special care should be taken when machining the end of the rail facing the resin layer.

A specific example will be explained with reference to FIG. 6. As shown in the figure, the end side 3a of the rail facing the material layer 13 is bent in a direction away from this resin layer, and the end of the inner rail having this material layer 13 is bent. It is preferable that the side 11a has a cross-sectional shape that is separated from the opposing rail 3. In this case, of course, it is effective even if the rail 3 has the same or other surface layer, or if only the outer rail 10 has a low friction resistance material layer.

Next, a configuration for regulating the movement range of both rails will be described.

Since the slide rail used in the reading device M of the present invention has a structure in which the inner rail and the outer rail move relative to each other via a low friction resistance material layer, a convex regulating member is provided on both rails, and the convex portions of both rails are provided with a convex regulating member. It is possible to restrict the movement range of both rails with a simple configuration in which the two rails are brought into contact with each other.

Incidentally, in the conventional rail using steel balls as shown in Fig. 9, a member for regulating the movement of the steel ball retainer 27 between both rails and a member for regulating the movement of the rail relative to this retainer are required. Therefore, it was difficult to obtain high precision in the complexity of the structure and the setting of the movement range. It can be said that the above slide rail solves the problems of conventional rails using steel balls in this respect as well.

FIG. 7 is a perspective view showing an example of forming the above-mentioned convex portion, and as shown in the figure, a portion of the outer rail 10 is punched out to form the convex portion 17. Convex portions are formed in the same manner on the inner rail 1, and the range of movement is regulated by contact between the convex portions of both rails as the rail moves. Of course, instead of punching, a protrusion formed from a piece of iron or the like may be fixed by welding or the like, or the protrusion may be provided on the main body device side or the moving target side.

FIG. 8 is a sectional view of the rail showing an embodiment of the member for regulating the movement range of the slide rail.

The convex portions 14 to 17 of the regulating member of the inner rail are formed to be inclined at different angles as shown in the figure, and by making contact at an angle β, it is possible to further improve the contact accuracy. In addition,
Convex portions 14 and 15 in the figure restrict the left movement range of the outer rail when the race is placed in the direction shown in FIG. 1, and convex portions 16 and 17 conversely restrict the right movement range. For this reason,
The protrusion 15 is located closer to the left end of the rail 1, and the protrusion 14
On the contrary, it is located at the right end of the rail 10.

On the other hand, the protrusion 16 is located closer to the right end of the rail 1, and the protrusion 17 is located closer to the left end of the rail 10.

The pairs 14, 15 and 16, 17 at both ends are provided at positions where they do not interfere with each other due to movement of the rails. Here, the positions of the respective convex portions 14 to 17 are indicated by Δ marks in FIG. 2.

Next, a structure for improving the durability and sliding action of the low friction resistance material layer provided on the rail will be devised.

As mentioned above, in order to increase the durability of the material layer 13 and to make it slide well, the end side 3a of the rail facing the material layer 13 should be perpendicular to the direction of movement of the rail, as shown in FIG. It is preferable to bend the rail in a direction away from this resin layer, or to make the end side 11a of the rail with the resin layer 13 have a cross-sectional shape away from the opposing rail 3.
Specifically, as shown in the partially enlarged sectional view of FIG.
It is preferable that the inner rail 1 is bent inward at an angle θ1 (approximately 5° to approximately 10°) from the sliding portion with the outer rail 10. In the example shown in FIG. 11, the cross section of the end side 3a of the inner rail 1 is rounded to form an arc with a radius R. In the case shown in FIG. 12, the durability of the material layer 13 can be improved by cutting out the sliding part of the inner rail 1 in a straight line in the direction in which the sliding part of the inner rail 1 separates from the sliding part of the outer rail 10. Naturally, it is effective to apply such a shape to both ends of the rail in the longitudinal direction.

In order to protect the solid resin layer of the sliding portion from wear caused by sliding of both rails, it is also possible to make the shape of the rail itself different from that shown in FIG. 1 above. In the case of FIG. 13, the inner rail 1a itself is made of a solid synthetic resin such as polyacetal, nylon, or polycarbonate resin, and one outer rail 10a is made of a metal plate, and the inside of this metal plate is made of the above-mentioned low friction resistance material. A layer 13 is coated and provided. In this case, by taking advantage of the characteristics of the resin of the inner rail 1a, the sliding part with the outer rail is thickened and the cross section is rounded, thereby protecting the solid resin layer 13 and further improving the sliding action. . In the case shown in FIG. 14, the sliding portions of the inner rail IC and the outer rail 10b have rounded cross sections, thereby improving protection and sliding action.

In addition, as a modification of the above example, a metal rail 1b may be provided in the resin as shown in the figure as a reinforcing material for the inner rail 1a using a solid resin as shown in FIG. 13, or conversely, a resin may be attached to the metal rail 1b. Also good. Next, the slide rail in Figure 15 does not have a symmetrical shape, and the inner rail 1
The left side of the outer rail 10 forms a convex guide part 1d by the end of the rail, and a concave guide part is formed by simply bending the left side of one outer rail 10.

What can generally be said about each of the embodiments described above is that in order to improve the sliding action, in order to further reduce the frictional force, both rails should be brought into surface contact as shown in FIGS. 10 and 13. Rather than sliding, it is preferable to slide by one tree or by a small number of line contacts in order to further enhance the sliding action. Therefore, in the case of a rail as shown in FIG. 14, it is effective to slightly change the curvature of the sliding surfaces of both rails.

In the above embodiment, the inner rail is attached to the main body device, but the outer rail may be attached to the main body device.

Further, in the above embodiment, the slide rail is used horizontally, but it may be rotated 90 degrees and used in an upright position.

As for driving the document table, an example using a rack and a pinion gear has been shown, but one end of a wire may be tied to the document table and this wire may be driven using a motor pulley. Further, the slide rail may be fixed by directly drilling a hole in the glass plate serving as the document mounting table without using a guide member.

Other examples of reading devices include not only electrophotographic copying machines but also image sensors used to convert image information into digital signals and facsimiles. In this case, the photoreceptor uses a solid-state image sensor such as a CCD element in addition to the electrophotographic photoreceptor.

(Effects of the Invention) As described above, the image reading device of the present invention uses the scoop 1-rail, which has an inner rail, an outer rail, and a low frictional resistance material layer therebetween, as a supporting guide rail for placing the original. Because of this, the scale does not move smoothly, and there is a moderate amount of frictional resistance between the rails, and the scale is less likely to be adversely affected by the vibrations and inertia that accompany movement.
Makes the rail movement speed stable. In addition, since the sliding part of the inner rail is covered by the sliding part of the outer rail, even if the plate is placed horizontally on top of the main unit as shown in Figure 4, the mounting process is as shown in Figure 4. It is possible to receive force in both the downward and upward directions shown by the arrows, and the fifth
It is also possible to receive a horizontal load as shown by the arrow in the figure. Since the rails held in this manner can be moved while maintaining high positional accuracy, they are ideal for use as rails for placing originals in image reading devices where positional accuracy is required.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the main parts of an image reading device to which the present invention is applied, Fig. 2 is a side view thereof, Fig. 3 is a perspective view of a slide rail applied to the reading device of the present invention, and Fig. 4 is the same rail. 5 is a sectional view of the rail, FIG. 6 is a partially enlarged sectional view of the sliding part of the rail, FIG. 7 is a perspective view of an example of the movement regulating member, and FIG. 8 is a cross-sectional view of the rail. 9 is a partially enlarged sectional view of a rail using conventional steel balls; FIGS. 10 to 15 are sectional views showing other embodiments of the slide rail. It is. In the figure, ] is the inner rail, 2 is the mounting rib plate constituting the connecting part, 4 is the sliding part of the inner rail, and 10
Reference numeral 11 indicates an outer rail, 11 indicates a rib plate for removing the outer rail, 12 indicates a sliding portion of the outer rail, 13 indicates a low friction resistance material layer, and 14 to 17 indicate convex portions constituting a regulating member. Showa 8

Claims (4)

[Claims] (1) In a document reading device that forms a document image on a moving document table onto a photoreceptor by slit exposure, there is a transparent support plate on which the document is placed, and a device that guides the movement of this support plate relative to the document reading device main body. An outer rail having concave guide portions on both sides extending in the longitudinal direction, a connecting portion connecting these concave guide portions along the longitudinal direction, and a convex guide corresponding to the concave guide portions of the outer rail. and a low friction resistance material layer provided on the sliding portion of at least one of the inner rail and the outer rail, one of the rails is attached to the device main body, and the other rail is attached to the support plate side. a slide rail to be attached to the support plate; a drive source for the support plate; a drive force transmission means for transmitting the drive force of the drive source to the support plate; a means for regulating the movement range of the rail; and a drive source for the support plate; A document reading device comprising: a slit aperture orthogonal to each other; a light source for illuminating the document; and an optical system having an imaging lens for forming an image of the document passing through the slit aperture onto a photoreceptor. (2) The document reading device according to claim (1), wherein the photoreceptor is an electrophotographic photoreceptor. (3) The document reading device according to claim (1), wherein the photoreceptor is a CCD element. (4) The document reading device according to claim (1), wherein the concave guide portion and the convex guide portion slide with curved surfaces facing each other.