JPS63106740A - Original scanner - Google Patents

Abstract

PURPOSE:To read an original with a high precision and simplify building-in of a scanner and reduce the cost by providing a pressing member, which is pressed to the face opposite to the original placing side of an original platen or the surface of another member joined with the original platen into one body and is moved together with a read scanning unit a the time of back and forth moving, on one side of the read scanning unit. CONSTITUTION:One side of a read scanning unit 18 is supported as the guide reference by a guide shaft 19, and a pressing member is provided on the other side and is pressed to the original platen. That is, a reference pressing roll 21, a reference pressing roll 22, and a pressing roll 23 are freely rotatably and axially set to the unit 18, one end of a lever 24, and the shake fulcrum shaft of the lever 24 respectively. These rolls 21-23 are rolled on surfaces of members, with which they are brought into contact, when the unit 18 is moved. Since the read scanning unit 18 is mechanically floated from a device body in this manner, distortion is difficult to occur, and an original is read with a high precision to stabilize the quality of recorded images.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document scanning device used in thermal printers, copying machines, and the like.

Figure 8 shows an example of a conventional device. A document 0 on a document table 1 made of glass is placed on a document table 1 made of glass, with an illumination light source 2 connected to a first mirror 3.
The illumination is scanned by moving to the right in the figure. The reflected light image from the document during this scanning is reflected by the first mirror 3 and the second mirror 4 which also moves in the same direction. It is reflected by the third mirror 5, etc., passes through the imaging lens 6, and enters the CCD array 7 located at this imaging position, where the document image is read. The illumination light source 2 and the mirror system can be moved by integrating them into an integrated unit. Generally, this type of scanning optical system must be moved with high precision, but in this conventional example, the illumination light source, mirror system, etc. move separately from the imaging lens 6, CCD array 7, etc. Therefore, for example, if the angle of the mirror is deviated, the scanning light will no longer be accurately incident on the CCD array, and in some cases, reading may become impossible.

In addition, since the mirror system and the like require a predetermined length for travel, the device itself becomes bulky. Furthermore, it takes a lot of time to adjust the position and tilt of the mirror system, CCD array, etc., and the strength of the unit that integrates the illumination light source and mirror system must be increased accordingly, resulting in high costs. It becomes.

In addition, as shown in FIG. 9, a unit 8 that integrally incorporates not only an illumination light source and a mirror system, but also an imaging lens, a CCD array, etc., is guided by two mutually parallel guide shafts 9, 9. Although there is a conventional example in which the unit is driven in this manner, in addition to requiring a large force to drive the unit, the rigidity of the unit itself must be increased accordingly, making it difficult to assemble.

SUMMARY OF THE INVENTION In view of the above-mentioned points, an object of the present invention is to provide a document scanning device that can read a document with high accuracy, and that can be assembled easily and at a low cost.

In order to achieve the above object, the present invention provides an illumination light source that illuminates a document on a document table, an imaging lens system that forms an image of reflected light from the illuminated document, and the imaging lens system. A reading sensor provided at an image forming position for the document table is integrated, and a reading scanning unit is provided which is driven reciprocatingly in the direction of the document table, and at least one side of the reading and scanning unit is provided with a reading sensor installed at an image forming position on the document table and a document placed on the document table. The present invention is characterized in that a pressing member is provided on the opposite surface, or on the surface of a separate member integral therewith, so that the pressing member moves together with the reading/scanning unit.

The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows a document scanning device according to an embodiment of the present invention.

In the figure, an illumination light source 12, which is composed of an LED or the like, illuminates the document on the document table 11. 1st mirror 13° 2nd mirror 1
4. Third mirror 15. The imaging lens system 16, the CCD array 17, which is an example of a reading sensor, and the like are integrally assembled within the unit 18.

The reading/scanning unit 18 is driven back and forth in the direction of the arrow by a drive means (not shown), and at this time, the image of the document ○ is read.

That is, the illumination light source 12 illuminates and scans the original O as the unit 18 travels, and the scanned light image at this time is transmitted to the first mirror 13 . Second mirror 14. The light enters the imaging lens system 16 via the third mirror 15, where it is imaged and projected onto the CCD array 17.

Since the reading element of the CCD array 17 is extremely small, about 10 μm, the image of the original O is
The image is reduced in size and formed on the CCD array 17. For this reason, the illumination width is also 2 m/m wide on the document surface.
On the D array surface, the slit becomes approximately Q, 2 IIl/m. When considering energy efficiency, the width of this illumination slit should be about 1 to 2 m/m, but in the past, a correspondingly wide illumination width was required to align the parallelism with the CCD array. It is.

When this kind of parallelism becomes distorted and becomes large,
No light enters the CCD array.

It becomes impossible to read. One of the causes of this is that the positions and inclinations of the illumination light source, mirror system, imaging lens system, CCD array, etc. are out of alignment.

Therefore, in the present invention, the optical elements as described above are integrated into one unit, and this is driven.

In this case, the unit is strong against twisting and bending,
It is necessary to have high rigidity, and it is desirable to prevent distortion of the main body structure from entering the unit side.

Therefore, as shown in FIG. 2, one side of the reading scanning unit 18 is supported by a guide shaft 19 as a guide reference, and a pressing member is provided on the other side.

I pressed this against the manuscript table.

That is, the standard pressing roller 21 is rotatably mounted on the unit 18, the standard pressing roller 22 is rotatably mounted on one end of the lever 24, and the pressing roller 23 is rotatably mounted on the pivot shaft of the lever 24.

When the reading scanning unit 18 is installed in the main body of a printer, copying machine, etc., as shown in FIGS. Also, the reference pressing roller 22 is similarly pressed against the lower surface by the elasticity of the spring 25 applied to the lever 24. Further, the pressing roller 23 contacts the extending guide portion 26a of the upper structure 26 to which the document table 11 is attached.

When the unit 18 moves, these rollers 21, 22, and 23 roll on member surfaces that are in contact with each other.

According to this configuration, strain applied to the reading scanning unit can be relieved. Further, in this embodiment, a roller was used as the pressing member. Since it is a three-point contact type, it has a low friction function and can reduce the driving force. Note that the pressing force of the rollers 22 against the document table 11 is determined regardless of the posture of the main body of the apparatus, that is,
The force is set so that the roller remains in contact with the document table 11 even if it is tilted or turned upside down. In other words, the elasticity of the spring 25 is set to such an elasticity that it can achieve such a function.

In this embodiment, the rollers 21 and 22 are brought into contact with the document table 11, but they may be brought into contact with another member integral with the document table.

Note that the guide shaft 19 shown in FIG. 1 needs to be horizontally mounted so as to maintain a constant distance from the document table 11. Therefore,
It is screwed and fixed to the upper structure 26, which is a support for the document table 11, to facilitate initial adjustment and to prevent displacement during assembly.

As shown in FIG. 3, of the reference pressing rollers 21 and 22, the roller 21 is arranged near the document reading position. In this way, compared to arranging it far away, it is possible to prevent the roller from being affected by the distortion of the roller contacting member from the roller to the reading position, and the reading accuracy can be improved. Since the position of the pressing roller 23 is also relatively close to the document reading position, its pressing force effectively contributes to assisting the above function.

FIG. 5 shows an example without the guide shaft 19 (FIG. 2).

Pushing rollers 28 are rotatably mounted on both sides of the reading scanning unit 18. Further, a pair of levers 30 are pivotally mounted on both sides thereof, a pressing roller 29 is rotatably mounted on one end of the lever, and a spring 31 is hung on the other end.

The reading scanning unit 18 is configured in this manner.

As shown in Fig. 6, the document table mounting frame 3 of the main body of a printer, etc.
2, the roller 28 is attached to the document table 11, and the roller 29 is attached to the document table 11.
are pressed against the guide portions 32a, respectively. A side guide 33 extends from the end surface of the unit 18, and this
The unit 18 is fitted into a guide portion 32b of the document table mounting frame 32, so that the unit 18 is guided.

As described above, in these embodiments, the reading scanning unit is mechanically floated from the main body, so distortion is less likely to occur and reading is performed with high accuracy.
The quality of recorded images becomes stable.

In addition, since the reduction ratio is large, the depth to the CCD array surface is shallow, making it easy to lose focus.

Integrating the optical elements as described above into an integrated unit is advantageous in this respect.

Further, similar effects can be obtained even if a same-size sensor other than a CCD array is used as the reading sensor. The same magnification sensor has a shallow depth, so it is effective to make the pressing roller lie on the document table in the same way.

Note that the rigidity of the reading scanning unit is set to be stronger than the rigidity of the main body. In addition, as shown in FIG. 7, even if the main body 34 of a thermal printer, portable copying machine, etc. is used upside down, it is possible to read the document ○. Note that, in addition to the roller, a sliding member may be used as the pressing member, and the same function can be achieved.

As mentioned above, according to the present invention, there is no need to increase the precision of parts so much, there is no need to adjust the orientation of optical elements during assembly, the rigidity of the main body structure can be low, and the reading The system is compact, the document table does not move, so it is easy to place the document, and even if the posture of the main body of the device changes, reading is possible, and the driving force required for the chin and drive is small.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is a perspective view of the reading and scanning unit of the above embodiment, Fig. 3 is the constituent teeth of the mounting portion of the pressing roller of the above embodiment, and Fig. 4 is 5 is a perspective view of the reading and scanning unit on the separate actual flow side, FIG. 6 is a sectional view of the main body of the device with the above reading and scanning unit assembled, and FIG. 7 is a sectional view of the main body of the device upside down. FIG. 8 is a configuration diagram of a conventional example, and FIG. 9 is a perspective view of another conventional example.

Claims (2)

[Claims] (1) An illumination light source that illuminates the document on the document table, an imaging lens system that forms a reflected light image from the illuminated document, and a reading sensor that is provided at an imaging position with respect to the imaging lens system. A reading scanning unit is integrated and is driven reciprocally in the direction of the document table, and at least one side of the reading and scanning unit is provided with a surface of the document table opposite to the placed document, or a separate part integral therewith. A document scanning device characterized in that a pressing member is provided on a surface of the member and moves together with the reading and scanning unit. (2) The document scanning device according to claim 1, further comprising at least a pressing member provided near the document reading position.