JPS6189767A - Original reading device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document reading device for reading document images using, for example, a digitally controlled copying machine or a facsimile transmitter.

[Conventional technology]

Conventionally, it has been known that a document reading device uses an optical system to sequentially project a document image onto the photosensitive surface of the reading elements while moving an array of reading elements arranged in one dimension and having a scanning function. There is. That is, main scanning is performed by the scanning function of the reading element, and sub-scanning is performed by the movement of the reading element.

To move the reading element array, connect loop wires to both sides of the moving table on which the reading element array is attached.
The loop wire is suspended around a pulley to drive the pulley.

However, the amount of expansion and contraction of the wires on both sides is different,
If the diameters on both sides of the drive system such as the boob or other gears are out of alignment or the amount of eccentricity is different, the reading element array will be tilted. As a result, there is an inconvenience that the image is read as a distorted image.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION The present invention aims to eliminate the drawbacks of the conventional apparatus and provide a document reading apparatus that can perform accurate reading.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention uses an optical system to project a document image onto reading elements that are arranged in a one-dimensional direction and performs main scanning in that direction, and the reading elements are attached in a direction that intersects with the one-dimensional direction. In a document reading device that performs sub-scanning by moving a moving member, the guide member guides the movement;
A method is adopted in which the joining surface in the one-dimensional direction with the sliding member attached to the member is located at a position corresponding to a reference line for changing the projection magnification of the optical system.

[For production]

Since such a means is adopted, the reading element moves in the sub-scanning direction without being displaced at least at a position corresponding to the reference line for changing the projection magnification of the optical system.

〔Example〕

FIG. 1 is a longitudinal cross-sectional view of an embodiment of a document reading apparatus to which the present invention is applied, and FIG. 2 is a cross-sectional view thereof. In these figures, a book document O to be read is placed on a document table glass plate l along an alignment guide 4. As shown in FIG. An original illumination lamp 2 equipped with a reflective shade 3 illuminates the image surface of the original 0, and the reflected light is imaged on the light receiving surface of the reading element array 6 by a lens array 5, which is an imaging optical system. be.

The reflective shade 3, document illumination lamp 2, lens array 5, and reading element array 6 are each attached to a moving table 8.

As shown in FIG. 3, the lens array 5 is made up of short-focus, small-diameter imaging lenses such as SELFOC lenses (trade name) arranged in the X direction. The lens array 5 is fitted into a notch in the movable table 8 and is held down and fixed by an elastic member 9 such as a partially bent plate spring or rubber, so that deformation can be absorbed even if the lens array 5 expands or contracts due to heat generated by the lamp 2, etc. It's Nishide. Further, the reading element array 6 has a base 6a connected to an elastic member l such as a plate spring.
It is held in place by O. An end A (see FIG. 2) of the reading element array 6 is a main scanning start end, and a moving line of this end A in the Y direction becomes a reference line in the main scanning direction.

As shown in FIG. 4, sliding members 12a-12b, 12c, and 12d whose lower sides are sliding surfaces are attached to the lower surface of the moving table 8, and guide rails are fixedly installed on the device main body side. They are placed on 13a and 13b, respectively. Furthermore, the movable table 8 has a sliding member 15 that corresponds to the side surface of the guide rail 13a.
is fixed with a mounting plate 16, and a sliding member 17 that faces the sliding member 15 and sandwiches the guide rail 13a is mounted with an elastic mounting member 18. The contact point B between the guide rail 13a and the sliding member 15 is located directly below the end A of the reading element array 6 (see FIG. 2).

Therefore, the movement guide line of the reading element array 6 and the reference line in the main scanning direction coincide when viewed from the optical system 5 side. FIG. 5 is a side view of the vicinity of the reading element array 6, in which the contact point B between the guide rail 13a and the sliding member 15 is located directly below the reference C of the reading element array 6 in the sub-scanning direction.

Note that a leaf spring, a rubber plate, or the like is used as the elastic mounting member 18. Sliding member 12a*12b*12c fist 12d-15.1
7 is made of wear-resistant and low-friction material such as ultra-high molecular weight polyethylene. Also, sliding member 12a*12be1
2ce12de15*17 have the same shape,
As shown in FIG. 6, for example, the sliding member 12a has an oblong projection 20 that fits into an oblong hole 21 of the moving table 8 to prevent rotation. A spring ring 23 fits into the cylindrical protrusion 22 that has passed through the oval hole 21 and prevents it from coming out.

As shown in FIG. 7, the moving table 8 has wires 25a and 25b
are connected by fasteners 26a and 26b, respectively. The wires 25a and 25b are respectively suspended by drive pulleys 28a and 28b and driven pulleys 29a and 29b. A drive shaft 30 to which drive pulleys 28a and 28b are attached is connected to a motor 33 (see FIGS. 1 and 2) by a belt 32. The driven pulleys 29a and 29b are connected to the device main body chassis by springs 35a and 35b, and the wire 25a
and 25b maintain appropriate tension. The driving pulleys 28a and 28b and the driven pulleys 29a and 29b are arranged below the first stop fittings 26a and 26b, and the moving platform 8 is pressed against the guide rails 13a and 13b.

FIG. 8 shows how the electrical signals from the reading element array 6 are transferred to the wiring board 3.
8 is a diagram showing the state of electrical wiring that is transmitted to the terminal. The flexible wiring 36 is held down by holding plates 37a and 37b so as not to apply stress to the electrical contacts of the reading element array 6.

With the above configuration, when the motor 33 rotates, the moving table 8 moves in the direction of arrow Y along the guide rails 13a and 13b. That is, sub-scanning is performed by the original illumination lamp 2, the imaging lens array 5, and the reading element array 6. At this time, since the guide rail 13 is sandwiched between the sliding members 15 and 16, it does not swing in the direction of the arrow X, that is, in the main scanning direction.

Figure 9 shows that due to the difference in the amount of elongation between wires 25a and 25b,
This shows the state when the moving table 8 is tilted. It is tilted around the contact point B between the guide rail 13a and the sliding member 15. α is its inclination angle. D and E indicate both left and right ends of the reading element array 6, respectively. Since BD<BE, the difference in reading width between point D and point E is in<'la. Since the positioning guide 4 of the original glass table 1'' is provided on the point D side, when changing the magnification based on the guide 4, the deviation of the magnification change reference is reduced and the magnification error in the main scanning direction is also reduced.

In the embodiment described above, the movement guide reference (contact B) in the sub-scanning direction is placed closer to the document positioning guide 4 side, but in an apparatus that changes magnification based on the image center OC of document 0 as shown in FIG. As shown in FIG. 11, the movement guide reference G is configured to be directly below the image center Oc. Distance m from the contact point G between the sliding member 15' and the guide rail 13c to the image center Oc
is within ±1741 when looking at the length of the reading element array 6 in the main scanning direction. By arranging the magnification reference and the movement guide reference at corresponding positions in this way, the magnification error in the main scanning direction can also be reduced.

〔Effect of the invention〕

As explained above, in the document reading device of the present invention, the reading element moves in the sub-scanning direction without positional deviation at least at the position corresponding to the reference line for changing the projection magnification of the optical system. Double errors can be suppressed to a minimum, allowing extremely accurate reading.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of a document reading device to which the present invention is applied, FIG. 2 is a cross-sectional view thereof, FIGS. FIG. 11 is a diagram illustrating another embodiment. 0 is a document, 2 is a document illumination lamp, 5 is an imaging lens array, 6 is a reading element array, 8 is a moving table, 12a*12b*
12c*12de15e17 is a sliding member, 13a/31
b is a guide rail, 25a*25b is a wire, A is a scanning reference position, B is a moving direction reference, X is a main scanning direction, and Y is a sub-scanning direction. JP-A Sho Gl-89767 (4) JP-A BRGI-89767 (6) JP-A Sho GL-89767 (7)

Claims (1)

[Claims] 1. An optical system projects a document image onto reading elements that are arranged in a one-dimensional direction and performs main scanning in that direction, and performs sub-scanning by moving a movable member to which the reading elements are attached in a direction that intersects the one-dimensional direction. In the original reading device, a joint surface in the one-dimensional direction between the guide member that guides the movement and the sliding member attached to the moving member corresponds to a reference line that changes the projection magnification of the optical system. A document reading device characterized by: