JPS5941963A - Original reader - Google Patents

Abstract

PURPOSE:To read a picture distinctly and uniformly even in case of reading a rather thick original, by constituting so that a distance between an original reading means and an original becomes constant even if the height of an original holding means is varied. CONSTITUTION:A leg member 8 is fixed to a head 4, and the leg 8 moves along the slit. Guard rails 171, 172 are fixed in a case 1, and the head 4 moves along the guard rails 171, 172. A leg member 7 is fixed to a frame member 6 of an original 0 holding plate 3. The holding plate 3 is made rotatable by making the rail 172 as an axis. The leg member 7 has a small hole, in which a tension spring 27 is detained. The spring 27 is extended in the direction for narrowing a distance between the base part of the holding plate 3 and the rail 172. However, since a hole 7' engaged with the rail 172 is a long hole, the holding plate 3 can move up and down. In other words, a press-contacting position of the holding plate 3 and the face to be read of the original 0 moves up and down in accordance with the thickness of the original.

Description

[Detailed Description of the Invention] This BA is a 7mm 7mm digital copier, an image! !
The present invention relates to a document reading device in a collection device, etc. More specifically, the present invention relates to an improvement in the mechanism of a device that captures an image of a document and forms an electrical signal corresponding to the image.

In a typical document reading device, a document is placed on a document table with the side to be read facing downward, and the document is scanned from below the document table. However, with such an apparatus, it is inconvenient to cover the important part of the original to be scanned with a blinding sheet, or to overlap multiple originals for composite reading.

A document reading apparatus of a type in which a document is placed on a document table with nine sides to be read facing upward is disclosed in Japanese Patent Application Laid-open Nos. 55-157761-4 and the like.

In the apparatus disclosed in this publication, a document is pressed against a document table by a document presser plate having a transparent plate, and a button is provided to scan the surface of the document to be read using a mirror from above the presser plate. The document table is made of elastic cushioning material, and when a thick document such as a book is placed on the document table, the document table is elastically deformed to keep the surface to be read at a constant height. It is configured. However, even if such an elastic document table is used, if the thickness of the document increases further, the height of the surface to be read of the document will not be higher than the predetermined height. , the scanning mirror is tilted, making accurate reading impossible, or the optical path length between the surface to be read and the lens changes, making accurate reading impossible.

Therefore, the purpose of the present invention is to solve the drawbacks of the above-mentioned conventional devices,
To provide a document reading device capable of accurately reading information on nine surfaces of a document to be read even if the position of the surfaces is high.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an external perspective view of one embodiment of the present invention.

In FIG. 1, a document table 2 is provided at the top of a main body exterior box 1. The document table 2 is made of a flexible elastic material such as sponge rubber. A document 0 is placed on the upper surface of the document table 2 with the surface to be read facing upward. The manuscript plate 3 is oriented with an arrow centered on the axis described below.

Rotates in the U direction. Rotating the plate 3 in the direction of arrow U is referred to as opening the plate 6 with respect to the document table 2, and rotating in the direction of the arrow U is referred to as closing the plate 5 with respect to the document table 2. The above rotation of the plate 3 is performed manually by the operator. However, an automatic opening/closing device may also be provided.

The manuscript plate 3 has a transparent glass flat plate 5 and a frame member 6 to which the glass flat plate 5 is fixed.

When the presser plate 3 is closed to the table 2 as shown by the two-dot chain line (3), the glass flat plate 5 is evenly spread over the entire surface of the document O placed on the document table 2 to be read. The document is crimped or closely attached to securely hold the document on the stand 2. If the document O is thick, such as a book, the document table 2Fi is compressed and deformed due to the weight of the document itself and the document being pressed from above by the presser plate 3, and its thickness becomes thinner. The jammed original 0 sinks, and the height of its 9 surfaces to be read becomes lower than when the table 2 is rigid. Therefore, the height of the document to be read can be maintained at a constant height (standard height) up to a certain thickness, but if the thickness of the document becomes thicker than the amount that can be compressed and deformed, Even if it is held down by the plate 3, the height of the surface to be read will be higher than the standard height.

The scanning head 4 is located at the position shown in FIG. 1 (home position) when the apparatus is at rest or when the presser plate 3 is opened and closed relative to the table 2 in order to place a document on the table 2. When in the home position, the scanning head 4 is positioned away from the original cover plate (3) in a closed state relative to the table 2, and does not mechanically interfere with the opening/closing operation of the presser plate. After placing the document on the table 2 and pressing the presser plate 3 on the document 0 by rotating it in the direction of the arrow, pressing the reading command key 10 causes the head 4 to move.
moves in the sub-scanning direction F. During this movement, the original O is read. When the reading of the original 84 is completed, the head 4 moves back in the direction B, which is opposite to the direction F, and returns to the home position.

Inside the head 4, as shown in FIG. 2, there are original illumination rungs 11. ．． 112, reflective plate 12, mirrors 151, 13
□, lens 14. ．． 142. Photoelectric conversion device as an image sensor, for example, charge-coupled device (QC!D) 15. .

152 is fixed. The head 4 faces the nine sides to be read of the document 0 placed face up on the document table as described above, with the glass plate 5 of the presser plate 3 interposed therebetween, and moves along the path above the glass plate 5 in the direction of arrow F. Move to. And this moving lamp 11. , 11° and the reflecting plate 12 illuminate nine sides of the document to be read. The illuminated light from the p-plane to be read passes through a slit provided in the reflection plate 12, and is reflected by the mirror 13. ．． 15
□ and reflected to lens 14. ．． 142 and 00D 15. , 152. lens 141
OOD is the area perpendicular to the sub-scanning direction F, that is, half the width of the document in the main scanning direction.15. The image is formed on
The lens 14□ images the left half area onto the OOD 152. (30D15., 152 scans the image of the surface to be read of the original in one-dimensional line scanning in the main scanning direction, which is a direction perpendicular to the direction of arrow F. Thus, when scanning the original, C0D151 t
' 2 forms an electrical signal corresponding to the image.

This electrical signal is once stored in a known storage device and then used for image reproduction, or is immediately transmitted to an image reproduction device.

In the illustrated example, two solid-state image sensors OCD are used, but depending on the relationship between the number of pits of the solid-state image sensor CCD and the resolution to read the image, the solid-state image sensor
The number of D is set.

Let N be the unique number of bits of the solid-state 41+'i image element COD, the number n of solid-state image sensors CCD, the reading width B of the image document, and the resolution R, then n is determined so that the relationship NXn≧BxR holds. In the column shown, the number of bits of the solid-state image sensor CcD is 1728, the number of bits is 2, and the size of the document is B4 size (257
Assuming that the width (257 lines) of mm x 564 (nm) is to be main scanned: the resolution is 12 pels, then 1728X2≧257x12 3456≧5084 This device ff is responsible for the relationship where the above relational expression is satisfied. This allows the head 4 to be made smaller.

In addition to the COD, an image pickup tube or the like can be used as the photoelectric conversion element.

A leg member 8 is fixed to the head 4. The leg member 8 is inserted into the box 1 through a slit 9 provided in the outer box 1. Then, the leg 8 moves into the slit 9.

In Fig. 6, box 1 indicates the sub-scanning direction (direction of arrow F).
A long guide rail 17, . 172 is fixed. And this rail 17. At 172 are bearings 1B4, 18 . fixed to the legs of the scanning head 4 . is fitted into the sliding feature. Thus the head 4 is connected to the rail 17.
．． It moves in the F direction and the B direction under the guidance of 172.

Next, the drive system of the scanning head 4 will be explained. A wire drum 21 is fixedly attached to a shaft 20 of a drive motor 19 that can rotate in both forward and reverse directions, and a wire 22 is wound thereon. 22 pieces of wire are rotatably attached to a shaft fixed at a fixed position inside box 1! One end thereof is connected to the lower part of one of the bearings 182 via J 23 and 24 . Similarly, the wire 22 is rotatably attached to a shaft fixed at a fixed position in the box 1. After J 25 and 26,
The other end is connected to the lower part of the bearing 18□. Therefore, when the wire drum 21 rotates clockwise, the scanning head 4 drawn by the wire 22 moves in the direction of arrow F. When a predetermined length of the document is scanned, the drive motor 19 is reversed by a sensor (not shown), the wire drum 21 is rotated counterclockwise, and the scanning head 4 is moved in the direction of arrow B to the home position shown in the figure. It stops at another 7 inns, etc.

As described above, when the document O becomes thicker, the height of the object 0' to be read also becomes higher than the standard height. In this case, in order to uniformly press the glass plate 5 of the presser plate 3 onto the entire surface of the document 0 to be read, the presser plate 3 must be raised according to the thickness of the document O. Therefore, the presser plate is supported as follows.

Leg members 7 are fixed to the frame member 6 of the presser plate 6. The leg member 7 is provided with a long hole 7' as shown in FIG. 4, and a rail 172 is fitted into the long hole 7'. Therefore, as described above, the U
It becomes possible to rotate in the D direction. The leg member 7 has many small holes, and one end of a tension spring 27 is locked in this small hole.

The other end of the tension spring 2'7 is locked in a small hole in a ring 28 fitted to the rail 172. Thus spring 2
7 elastically pulls the presser plate 3 in a direction to narrow the distance between the base of the presser plate 6 and the rail 172. However, since the hole 7' that engaged with the rail 172 is a long hole, the holding plate 3
is movable up and down. The pressing position between the tab, the presser plate 6, and the multiple sides of the document O to be read is movable up and down depending on the thickness of the document. In this way, the holding plate 3 is attached to the rail 172 so that it can rotate and move up and down.
Due to the action of 7, the presser plate 3 rotates without wobbling. still,
The spring 27 may be omitted.

As described above, the position of the surface of the document to be read changes vertically depending on the thickness of the document. No matter where the position of the surface to be read is, the surface to be read and the lens 14. , 14□, the scanning head 4 is also movable up and down in order to keep the optical path length between 14□ constant.

As shown in FIG. 5, a shaft 30 is fixed to the vertically movable head 4, and a spacer roller 31 is rotatably attached to this shaft 30. The roller 51 then rides on a guide path 29 provided in the frame member 6 of the holding plate 6 and rolls on this guide path 29. Guideway 291d, Fi (+1
A guide rail 17.long in the direction parallel to the scanning direction F.
, 17□, parallel to the glass plate 5. Therefore, the head 4 moves parallel to the glass plate 5, or in other words, parallel to the surface to be read. During the movement of the tab scanning head 4 over the glass plate 5 in the direction of arrow F, the lens 14 . .

The optical path length between 142 and the surface to be read of the original is kept constant. Although FIG. 5 shows the spacer roller 31 and guide path 29 on the front side of the rotary head 40, similar spacer rollers and guide path are provided on the back side of the head 4.

Now, guide rail 17. ．． 172 is fixed in place. Therefore, the head 4 is connected to the rail 17. ．． It must move up and down relative to 172. In other words, the bearing body 1
8. , 182 to rail 17. ．． 172 so as to be movable up and down. In FIG. 6, the bearing body 18. ，
Inside the elongated hole 18' of 182 are an upper bearing 32 and a lower bearing 322.
is provided. The upper bearing 32., which slides on the upper part of the rail t'71+''z, is fixed to the bearing body 1B, 18□, and the rail 17.

A lower bearing 322 that is in sliding contact with the lower part of the shaft 172 is movable up and down within the elongated hole 18'. Guide bins 551.332 are fixedly planted in the lower bearing 322, and guide bins 33.33. .

632 is loosely inserted into the guide holes 18', 1B'' provided in the bearing main body 181+'''2. pin 6
3. .

A compression spring 55. is attached to the circumference of 63□. ．． 35□ is provided, and this spring causes the bearing body 18. , 182 are elastically biased downward. In this way, the presser plate 3 is not higher than the standard height, and when the head 4 is lifted upward, the bearing body 18. , 18. Mospring 531, 552'
It rises by the same amount as the rise of the head 4 while compressing it. In this state, the upper bearing 32. is Leh 1L17. , 172, but the rail 17. ．． 17. The lower bearing 32□ is connected to the spring 55. ．． 332, the head 4 is reliably guided by the rails 171, 172.

In the above example, the guide rail 17. ．． 172 is fixed in place. In the following example, guide tray #17. , 17. can be moved up and down.

In FIG. 7, the leg member 7 of the holding plate 3 has a normal round hole, into which a round bar rail 17 is fitted so as to be relatively rotatable. The tab holding plate 3 is rotatable about the rail 172 in the U direction and the D direction.

Also bearing 18. ．． 182 also has a normal round hole, and the round bar rail 17. ．． 172 are fitted in a relatively slidable manner. Therefore, in the example of FIG. 7, bearings 1B, 1B,
Therefore, the scanning head 4 is connected to the rails 17, . It does not move up and down relative to 172.

Rail 17. ．． 17□ is the rail support device 55. ．． 352
is supported by As shown in Figure 8.9, the rail support v1.55. , +52ha, 1/-/l/ 171,
172@ has a fixed movable member 55a and a fixed member 35t fixed to the outer box 1. Fixed member 35b
A guide groove 55c is provided, and a housing 55 (l) of a movable member 55a is slidably fitted into this guide groove 35c.Thereby, the member 65a is fixedly fixed vertically relative to the member 35b. This rod 35e is slidably inserted into a hole 55f provided in the fixing member 35t. A compression spring 55g is interposed between the movable member 35a and the fixed member 351). The spring 55g biases the movable member 55a downward, so that the tray 1717 is stably held at the 11 2 position at a height corresponding to the thickness of the document.

Note that the spring 55g may be omitted depending on the case.

In this way, in the apparatus shown in FIG. 7.8.9, the guide rail 1 guides the reciprocating movement of the scanning head 4 in the sub-scanning direction.
7. ．． By moving the scanning head 172 up and down, the scanning head 4 can be moved up and down depending on the thickness of the document.

In the above example, when the scanning head 4 is at the home position, the spacer roller 31 rests on the outer body 1' of the outer box 1. Therefore, in this state, the height of the head 4 is constant regardless of the thickness of the document.

The height of the head 4 is determined by the height of the roller 4 after starting to move in the F direction.
51 is placed on the presser plate 3 and raised to A%. At this time, the entrance portion 29' of the guide path 29 is formed into an inclined surface 24' that gradually becomes higher in the F direction so that the roller 61 rides smoothly on the presser plate 6.

The roller 31 of the scanning head 4 is the original ≠ 1 frame member 6 of the presser plate 3
Since the scanning head 4 is smoothly raised, no shock is generated at that time, and therefore, there is no risk of vibration occurring inside the scanning head 4 causing image disturbance, or damage to durability due to impact. Incidents that cause noise are prevented. In order to increase the above effect by making the slope 29' gentler, a groove is formed in the frame part 6 in the portion of the guide path 29 after the entrance 29', that is, even at the point where document scanning ends. Therefore, it is preferable to lower the height of the guide path 29.

The embodiments have been described in detail above, but according to the present invention, a device that reads a document by placing it face up on a document table can read a clear and uniform image even when reading a thick document. This contributes to good image reproduction.

Fig. 1 is an explanatory diagram of the outside of the embodiment of the present invention; Fig. 2 is an explanatory diagram of the internal structure of the scanning head; Figure 4 is an explanatory diagram of the legs of the original holding plate, Figure 5 is an explanatory diagram of the main parts of the device to explain the relationship between the scanning head and the original holding plate, and Figure 6 is a sectional view of an example of the bearing part. , Fig. 7 is an explanatory diagram of another embodiment of the invention, Fig. 8 is an explanatory diagram of the main parts of the device, Fig. 9 is a sectional view of an example of the movable rail support device, and Fig. 10 is an explanatory diagram of the spacer roller guide path. It is an explanatory diagram of an example.

In each figure 2...Manuscript table 6... Original holding plate 4...Scanning head /47\ 1414...Lens 11 2 15. 15□..., C0D 1717...Guide rail 11 2 1818... Bearing JinF body 1' 2 51...Spacer roller 354, 352...Rail support device.

Applicant: Canon Co., Ltd. 39

Claims (1)

[Claims] a document table on which the document is placed with the side to be scanned facing upward;
a document holding means that presses the document against the document table and is movable up and down according to the thickness of the document, and a scanning device that has a lens and an image sensor and faces the surface to be read of the document via the document holding device. , a supporting means for movably supporting the scanning means up and down, and a scanning means for keeping the distance between the scanning means and the surface to be read of the document constant (1-) even if the height of the document holding means changes. A document reading device comprising: a spacer means provided in the document holding device and abutting the document holding device.