JPS58199337A - Original scanning device - Google Patents

Abstract

PURPOSE:To obtain a titled scanner of a simple structure, by connecting two supporting members by one movable guide rod, and moving both supporting members in the velocity ratio of 1:1/2. CONSTITUTION:A cylindrical movable guide rod 31 is placed on supporting members 13, 14 movable in the direction as indicated with arrows C, C' while being guided by guide rods 11, 12 supported by a structure member 18 fixed to the machine frame. The first mirror 4 supported by the supporting member 13 and the second mirror 5 supported by the supporting member 14 scan an original when those supporting members move in the directions C, C', the movable guide rod 31 is placed slantingly in the original scanning directions C, C', is supported so as to be freely turnable by the first supporting member 13 by a supporting shaft 32, is supported by the second supporting member 14 by a holding tool 33, and also is supported by the structure member 18 by a holding tool 34.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a first supporting member carrying a first reflecting means and a second supporting member carrying a first reflecting means.
Relating to a document scanning device configured to scan a document on a document table by running a second support member carrying a reflecting means in the same direction parallel to the document table at a speed ratio of 1:V2. .

The document scanning device described above is used as a document reading device such as an electrophotographic copying machine or a facunmill. For example, in an electrophotographic copying machine, it serves as one component of an exposure optical system that forms an electrostatic latent image on a photoreceptor based on an original image.

FIG. 1 is a schematic diagram showing the exposure optical system of the electrophotographic copying machine. In the figure, an exposure optical system including a lamp 3, a first mirror 4, a second mirror 5, a lens 6, and a fixed mirror 7.8 is arranged below the document table 2 on which the document 1 is placed. There is.

The light emitted from the lamp 3 and reflected on the image plane of the original 1 passes through the first mirror 4, the second mirror 5, the lens 6, and the fixed mirror 7.8, and rotates in the direction of arrow A, as shown by the dashed line in the figure. The photoreceptor 9 is irradiated with light. In order to scan the original l, the lamp 3 and the first mirror 4 move together to the right in the figure at a speed V1, and at this time, the second mirror 5 extends from the first mirror 4 to the photoreceptor 9. In order to keep the optical path length constant, it moves in the same direction as the first mirror 4 at a speed of V/2. The dashed line 4' or 5° represents the position of the first mirror or the second mirror at the end of scanning, respectively, and the dashed line represents the reflected optical path at that time. By the above scanning, an electrostatic latent image corresponding to the original image is formed on the photoreceptor 9. It is a well-known conventional practice that the electrostatic latent image thus formed is subsequently subjected to development, transfer and fixing operations.

As mentioned above, in the exposure optical system, an important requirement is to move the first mirror 4 and the second mirror 5 in the same direction at a speed ratio of 1:', 4. The type of document scanning device has a first mirror 4 and a second mirror 5.
This is to realize the above movement of . Among document scanning devices of this type, a device using a drive system having two links as shown in FIG. 2 is known. This conventional document scanning device includes the following members: a first support member 13 that supports a first reflection mirror 4 and moves in parallel along a guide rod 11 and a guide rod 11 that supports a second reflection mirror 5; .12, and the first support member 15 on the first support member 13 and the second
A first link 17 is rotatably supported on each of the second fulcrums 16 on the support member 14, and a third fulcrum 19 is rotatably supported on each of the second fulcrums 16 and the structural member 18. A second link 21 is supported pivotally and has the same length between fulcrums as the length between fulcrums of the first link 17, and a wire 23 is connected to a racket 22 protruding from the front of the first support member 13.
The second fulcrum 16 is connected to a guide plate 27 projecting from the second support member 14. It is disposed within a long hole 28 provided and is movable through the long hole 28. The long hole 28 is
It extends in a direction perpendicular to the straight line connecting the first fulcrum 15 and the third fulcrum 19 in advance.

In the conventional document scanning device having the above configuration, when the first support member 13 moves in accordance with the movement of the wire 23 in the BB" direction, the first fulcrum 15 approaches or moves away from the third fulcrum 19. The link 17 and the second link 21 open and close, and the second fulcrum 16 moves along the length 28 and in the same direction as the first fulcrum 15 (BB''
direction) at the speed of a duck. The reason is that each fulcrum 15
It is easy to understand from the geometrical relationship when moving the first fulcrum 15 for an isosceles triangle with the vertex at ゜16.19.3
Thus, this type of conventional document scanning device uses two links 17.21 to connect the first mirror 4 and the second mirror 5.
The desired speed ratio is obtained. However, in this device, since the second fulcrum 16, which is the intersection of the two links, slides against the elongated hole 28 of the guide plate 27, the mechanism is complicated, and furthermore, the sliding fulcrum 16 and There is a drawback that it is difficult to maintain the accuracy of the elongated hole 28.

In addition to the above-mentioned drive system having two glues/grips, there is also a drive system that adopts the principle of sliding sliding.1However, in a document scanning device using this drive system, the device's During assembly, it is difficult to accurately determine the relative positions of the two mirrors, so there is a drawback that it is difficult to introduce automatic assembly. In addition, if the movable pulley mechanism is adopted for both the forward and backward movement of the mirror, two or more movable pulleys will be required, making the mechanism complicated and making it difficult to hook the wire. There are also drawbacks.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of conventional devices, it is an object of the present invention to provide a document scanning device that is simple in structure and easy to assemble.

Hereinafter, the present invention will be explained based on drawings showing embodiments thereof.

FIG. 3 is a perspective view of a document scanning device showing an embodiment of the present invention, and the same members as those in the conventional example shown in FIG. 2 are designated by the same reference numerals. In the figure, a first support member 13 and a second support member 14 are movable in the direction of arrow CC° while being guided by guide rods 11 and 12 supported by a structural member 18 fixed to a machine frame (not shown). A cylindrical movable guide rod 31 is arranged. The first mirror 4 and the second support member 14 supported by the first support member 13
The second mirror 5 supported by the second mirror 5 scans the original l (FIG. 1) when these supporting members move in the CC' direction. Hereinafter, the CC' direction will be referred to as the document scanning direction.

The movable guide rod 31 is arranged obliquely with respect to the document scanning direction CC°, is rotatably supported by the first support member 13 by a support shaft 32, and is supported by the second support member 1 by a holder 33.
4 and further supported to the structural member 18 by a retainer 34.

4 is a diagram showing the support shaft 32, the holder 33, and the holder 34 in detail along the line IV-IV in FIG. The movable guide rod 31 is fixed to the movable guide rod 31, and is fitted into a hole at the end of the movable guide rod 31. Although both sides of this end portion are shaved off and finished into a flat shape, it may be a cylinder as it is without any special processing.

Reference numeral 35 is a glue retainer for preventing removal. The holder 33 is a bearing holder 3 attached to a shaft 36 fixed to the upper part of the second support member 14 via a bearing 37.
It has 8. The bearing holder 38 has another bearing 39 in addition to the above-mentioned bearing 37, and the movable guide rod 31 is fitted into the outer bearing 39. This allows the movable guide rod 31 to move in the axial direction within the holder 33. Further, the holder 33 itself is also rotatable around the shaft 36.

The bearing 39 on which the movable guide rod 31 slides may be of either a multi-contact type or a full-contact type. The holder 34 has a bearing holder 38 having the same structure as the holder 33 described above, and the bearing holder 38 is rotatably supported by a shaft 41 directly fixed on the structural member 18. Ingredients 34
is fixed to the structural member 18, whereas the retainer 33
3 moves in accordance with the movement of the second support member 14, henceforth the holder 33 will be particularly referred to as a movable holder. In addition, support shaft 3
2 is the center of X2, the center of the shaft 36 on the second support member 14 is Y, and the center of the shaft 41 on the structural member 18 is Z,
Center Y is the midpoint between center X and center Z.

In FIG. 3, the front bracket 22 of the first support member 13 is connected to a wire 23 which is connected to a drive pulley 24 and idler pulleys 25 and 26, as in FIG. When the drive pulley rotates in the forward and reverse directions, the wire 23 moves linearly back and forth in the document scanning direction CC°, thereby moving the first support member 13 in the CC° direction. In this way, the winding transmission device consisting of the wire 23, the drive pulley 24, and the idler boots 1725, 26 is used as a driving means for driving the first support member 13; Any configuration may be used as long as it gives linear reciprocating motion to 13.

The present embodiment is constructed as described above, and operates as follows when scanning a document.

When the drive pulley 24 rotates in the D direction in the initial state shown in FIG. 3, the first support member 13 moves the guide rod 11.
12 in the C direction, and the support shaft 32 also moves in the C direction accordingly. The movable guide rod 31 supported by the support shaft 32 can be moved in the axial direction and rotated around the shaft 41 (FIG. 4) by the fixed holder 34 on the structural member 18, but other than these Since the movement is restricted, when the support shaft 32 moves in the C direction, the movable guide rod 31 moves along the support shaft 3.
20 so as to gradually increase the angle formed with the document scanning direction cc1.

FIG. 5 is a diagram schematically showing the movement of the movable guide rod 31 described above. In the figure, the angle made by the movable guide rod 31 with the document scanning direction CC- in the initial state shown by the solid line is θ. Note that each point x, y, and z is the same as the point indicated by the same letter in FIG. 4, and numerals 33 and 34 indicate a movable holder and a fixed holder, respectively. Support shaft 32 (third
When the center -X of (Fig.) moves by a distance @1 in the C direction and reaches the position Xo, the angle θg that the movable guide rod 31 (broken line) makes with the original scanning direction CC' is larger than the initial angle θ. While the center X moves to X', the fixed holder 34 rotates from the solid line to the broken line.

During this time, the movable guide rod 31 slides within the fixed holder 34 by an appropriate length and protrudes to the rear by that amount. 1. By the way, the movable holder 33 placed at an intermediate position of the movable guide rod 31 is attached to the shaft 36 (
4), and the second support member 1
4 in the document scanning direction CC', but other movements are restricted, so while the movable guide bar 31 moves from the solid line position to the broken line position, the movable holder 33 moves around the axis 36. The movable guide rod 31 slides within the movable holder 33 in the same way as in the case of the fixed holder 34. The center Y of the shaft 36 that supports the movable holder 33 moves in the same way as the movable holder 33 and reaches the position Yo.1 The center Y is the midpoint between the center X and the center Z, as described above. , Moreover, since the moving directions of the center X and the center Y are parallel (same as the original scanning direction CC1), if we imagine a triangle Xz The length of ° is a straight line XX°
In other words, if the center X moves by l in the C direction, the center Y moves by t/2 in the C direction. In this way, while the center X of the support shaft 32 on the first support member 13 moves by l within a certain period of time, the center Y of the shaft 36 on the second support member 14 moves by t/2. However, the moving speed of the second supporting member 14 is the same as the moving speed of the first supporting member 13, and the desired values for the first mirror 4 and the second mirror 5 (FIG. 3) are determined here. Scanning speed is obtained.

In addition, in the above description, the shaft 4 for supporting the fixed holder 34 is
1 was directly fixed to the structural member 18, but as shown in FIG. 6, it is preferable to make the fixing position of the shaft (41') adjustable.

In the figure, a shaft 41° that supports the fixed holder 34 is fixed to an intermediate member 42. The intermediate member 42 is fixed to the structural member 18 by screws 43;
Since the hole in the intermediate member 42 through which the screw 3 passes is formed in advance to have an appropriately larger diameter than the screw 43, the fixing position of the intermediate member 42, and therefore the fixing position of the shaft 41', is within the range of the hole for passing the screw. Adjustable within. If you do it this way,
Unreasonable work such as bending the movable guide 31 (FIG. 3) during assembly can be prevented. In other words, supporting the straight ti (movement guide 31 at three points (X, Y, Z: Fig. 3) requires great precision when manufacturing parts.
The assembly of the axis 41° at two points is performed according to the inclination of the movable guide 31 determined by the two points X and Y. The same can be said when applied to the Y point.

As described above, in this embodiment, one U pivoting guide rod 3
1 connects the first support member 13 and the second support member 14,
Since these move at a speed ratio of 1:rod, the structure is very simple. 5. Therefore, it is also possible to hold the sliding portion of the movable guide rod 31 and the holder 33 or 34 with high precision for a long time.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of an electrophotographic copying machine in which the present invention is implemented, FIG. 2 is a perspective view showing a conventional example of a document scanning device, and FIG.
The figure is a perspective view showing one embodiment of the present invention, FIG. 4 is a cross-sectional view showing the support shaft 32, the holder 33, and the holder 34 along the ■-fV line in FIG. 3, and FIG. FIG. 6 is a diagram schematically showing the movement of the movable guide rod 31, and is a diagram showing a modification of the method of fixing the shaft 41 for supporting the holder 34 in FIG. 4. 4...First reflecting means (first mirror) 5...Second reflecting means (second mirror) 2...Document mounting table, 1...Document, 31...
・Movable guide rod, 33...Movable holder, 34...
・Fixing holder, 13-...first support member 14 ・
...Second support member Fig. 3 Fig. 41...Pa 1 Fig. 5

Claims (1)

[Claims] The first supporting member supporting the first reflecting means and the second supporting member supporting the second reflecting means are moved parallel to the original mounting table t (by moving them in the same direction at a speed ratio of A to the original mounting table t). In a document scanning device configured to scan an upper document, a straight P is rotatably supported by a first support member, is arranged to be inclined in the document scanning direction, and crosses a second support member.
a pivoting kite rod, a movable holder provided on a second support member that supports the movable guide rod in an axially movable manner and is itself rotatable relative to the second support member, and a rotation center of the movable holder. 10 of the movable guide rod on the first support member so that the midpoint
1. A document scanning device comprising a fixed holder which is rotatable about a position opposite to the center of one movement and supports a movable guide rod so as to be movable in an axial direction.