JP3330250B2 - Document reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading apparatus for converting character or graphic information written on a sheet medium such as paper into an electric signal in an office machine or an information processing apparatus. The present invention relates to an apparatus characterized by the illumination means of a unit (document reading position).

[0002]

2. Description of the Related Art FIG. 14 is a view showing an example of a typical conventional structure of a reading section of a document reading apparatus capable of performing reflection reading and transmission reading of a document 3. Here, 31 is a transparent glass plate serving as a document table or document guide, 1 and 33 are light source lamps for document illumination, 34 is an image forming lens,
8, an image sensor; 35, a reflecting mirror for reflecting the reading light 27 toward the image sensor 28; 36, a light source lamp 3;
3 is a reflecting mirror for condensing light.

When the original 3 is a reflection original, the light source lamp 33 below the glass plate 31 is turned on, and the image is moved by moving the original 3 or by moving the reading unit 24 (in the case of a flat bed type). The original is scanned by the sensor 28 for reading. On the other hand, when the original 3 is of a transmissive reading type such as an OHP (overhead projector) sheet, the light source lamp 1 provided above the glass plate
Is turned on for reading. When the apparatus is of a flatbed type, the upper light source lamp 1 must be run synchronously with the reading unit 24 when reading a transparent original.

When disturbing light enters the image sensor 28, flare occurs and the reading quality deteriorates. When disturbing light enters when reading a black portion of a document, the density decreases, so that disturbing light enters the image sensor 28. You need to avoid doing this as much as possible. In particular, when reading a transparent original, the light from the upper light source lamp 1 and the lower light source lamp 33
6, the document 3 is illuminated from below, and the reflected light is superimposed on the reading light 27, so that the density of the black portion is reduced and the reading quality is likely to be reduced. Therefore, a slit 37 is provided under the light source lamp 1 to prevent diffusion of the illumination light and to prevent disturbance light from being generated.

[0005]

In the flatbed type document reading apparatus, the light source lamp 1 above the glass plate 31 runs together with the reading unit 24. Therefore, if the diameter of the light source lamp 1 is large, a large traveling space is required. Then, the device becomes large. In particular, since the upper light source lamp 1 is often housed in an openable / closable cover also serving as a document holder, if the tube diameter of the light source lamp 1 is large, the cover becomes thicker and operability when opening / closing the cover is reduced. Also have an adverse effect.

Therefore, as a light source lamp 1 for transmission reading,
Light source lamps having a small diameter of about 5 mm have been used.

However, when a small-diameter light source lamp is used,
Even if the illuminance is not different from that of normal diameter,
As shown in FIG. 15, when the reading position deviates from the center of the tube, the illuminance rapidly decreases. For this reason, the reading position and the center of the tube must be accurately matched, but it is difficult to obtain the required positional accuracy due to the restriction that the production cost must be avoided. In particular, in a flatbed type reader, the upper light source lamp 1 is connected to the reading unit 2.
4 and the glass plate 31 is interposed between them, and the upper light source lamp 1 is mounted in the opening / closing cover. It is impossible to integrate them, and it is extremely difficult to maintain the positional accuracy between the tube center and the reading position.

In the conventional structure in which the illumination light of the upper light source lamp is limited by the slit 37, light 32 from the side of the tube is used.
Pass obliquely through the slit 17, the effect of suppressing disturbance light is not sufficient.

Due to such various factors, it has been difficult for the conventional reading apparatus to achieve both reduction in size and cost of the apparatus and improvement and stabilization of the quality of read information. Accordingly, the present invention provides a document reading apparatus using a small-diameter light source lamp as a light source lamp, which effectively suppresses the occurrence of disturbance light with a simple structure, and provides a stable and high-quality reading apparatus. Is an issue.

[0010]

Means for Solving the Problems] document reader <br/> of the invention, the reading section of the document illumination lamps and to the small-diameter optical source lamp 1
In the document reading apparatus using a small-diameter light source lamp 1 both
It has a width slightly wider than the diameter of the lamp connected to the end.
To a U-shaped cross section according to the width of the square receiving member 4
The light-collecting sheet 2 made of a folded white resin sheet is
With the opening 13 of the light-collecting sheet facing the reading position 19 of the original 3
With both ends covered by the receiving member, the covered end portions
7 provided on the lamp holding frames 6 and 9 and a spring projection
8 or a holder 11.
Things.

The light-condensing sheet 2 can be provided with a slit 17 or a recess 18 in the longitudinal direction at the center of the wall surface in the longitudinal direction.

The small-diameter light source lamp 1 of the document reading apparatus having the above-described structure is particularly preferably used as a light source lamp for transmission reading.

In a document reading apparatus provided with a light source lamp 1 for transmissive reading, end faces 21 and 22 on the lamp side and the document side are polished between the light source lamp 1 and a document reading section 19, and a side face 25 is formed. It is preferable to provide an elongated condensing glass plate 20 in the tube axis direction of the light source lamp having a mirror surface on which aluminum is deposited.

According to a fourth aspect of the present invention, there is provided an original reading apparatus provided with a light source lamp 1 for transmissive reading, wherein an original reading section 19 and a reflecting mirror 35 for reading light 27 or an image forming lens 34 are provided. In the main scanning direction of the image sensor 28, which has polished the end faces 21 and 22 on the original side and the reflecting mirror or the image forming lens side, a disturbance light blocking glass plate 26 elongated in the main scanning direction is disposed with the end side 22 on the original side close to the reading section 19. It was done.

[0015]

As a structure for increasing the illuminance of the reading section illuminated by the light source lamp, a structure using a condensing reflector 38 as shown in the conventional structure of FIG. Although it is effective when the diameter is large, when the tube diameter of the light source lamp 1 is small, the width of the peak area of the illumination light becomes narrow due to the rapid diffusion of light, and the illuminance becomes sharp when the reading unit deviates from the center of the light beam. Causes a decline. On the other hand, a structure in which a ground glass or the like is interposed between the light source lamp and the reading unit to scatter light can broaden the width of the peak region of the illumination light to make the illuminance uniform, but the illuminance in the peak region is generally reduced. To decline.

On the other hand, the light-collecting sheet 2 of the present invention is
Since it is provided so as to cover the light source lamp 1, the attenuation due to diffusion can be reduced, and an efficient light collecting action can be obtained. In addition, since the illumination light is emitted relatively uniformly from the opening 13 of the light-collecting sheet over the entire opening width, even if the position of the reading unit and the center of the tube of the small-diameter light source lamp 1 is shifted, the amount of the shift is small. When it is within the aperture width of the condensing sheet,
A sharp decrease in illuminance does not occur, and a stable light amount in the reading unit can be secured. That is, according to the present invention,
Even when a small-diameter light source lamp is used, it is possible to increase the width of the peak area of the illumination light without lowering the illuminance.

Further, since the mounting of the light-collecting sheet 2 and the maintenance of the direction of the opening 13 thereof are performed with a very simple structure, the cost increase of the apparatus due to the provision of the light-collecting sheet 2 can be avoided, and It is extremely easy to replace the light-collecting sheet when the light sheet is damaged or deteriorated.

Since the illuminance of the light source lamp 1 is large at the center in the tube axis direction and the illuminance at both ends is reduced, in order to make it uniform in the tube axis direction, in a conventional apparatus, a shading plate is provided in the middle of the reading optical path. The shading effect has been obtained by providing 39 and changing the shape of the condensing reflection plate 38 as shown in FIG. According to the structure of claim 2 of the present application,
The shading action is obtained by allowing the light at the center of the light source lamp to escape from the slit 17 or the concave portion 18 of the light-collecting sheet, and the illumination light emitted from the opening 13 of the light-collecting sheet is uniformly distributed in the tube axis direction of the light source lamp. can do.

The condensing glass plate 20 guides the light entering from the end face 21 on the light source lamp side to the end face 22 on the reading section side without scattering, and can illuminate the reading section 19 with higher illuminance. Concentrating glass plate 20 from the side
The light incident on the side surface of the document is reflected and is not allowed to pass through the reading unit 19, so that the convergence of the light passing through the reading unit 19 of the document can be increased as compared with the conventional structure in which the slit 37 is provided. Light 32 that passes obliquely (see FIG. 14) is reflected by a light source lamp for reflection reading and other members, and it is possible to prevent deterioration in the quality of read information caused by disturbance light.

The disturbance light blocking glass plate 26 prevents the reading light from being diffused by the same light guiding action as that of the condensing glass plate 20, and blocks the light obliquely crossing the reading section, thereby providing the reading light 27. Of the ambient light is prevented from occurring.

According to the present invention, particularly in a flat-bed type document reading apparatus capable of transparent reading, the traveling space of the light source lamp traveling on the upper surface of the document table is reduced, and the apparatus can be downsized. Document cover with a built-in light source lamp can be made thin with good operability. Further, even if a movement error occurs between the reading unit 24 traveling above and below the platen and the small-diameter light source lamp 1 for transmissive reading, it is possible to avoid a change in the amount of light in the reading unit due to the movement error.

[0022]

FIG. 1 shows a first embodiment of the present invention. A light source lamp 1 having a tube diameter of about 5 mm is covered with a light-collecting sheet 2 formed by bending a white resin sheet into a U-shaped cross section. This is an example in which the above-mentioned structure is used as a light source lamp for transmission reading.

FIGS. 2 and 3 show examples of the fixing structure of the light-collecting sheet. At both ends of the small-diameter light source lamp 1, a receiving member 4 having a square cross section is provided, and a cable 5 extends from the receiving member. The light-condensing sheet 2 is bent in a U-shape according to the dimension of the side of the receiving member 4, and is fitted to the receiving member 4 to cover the light source lamp 1.

In the structure shown in FIG. 2, a seat 7 for receiving one side of the lamp receiving member 4 and a resilient projection 8 for receiving the opposite side are integrally formed on the resin frame 6 holding the lamp 1. The light source lamp 1 and the condensing sheet 2 are sandwiched and fixed between the spring projection 8 and the seat 7 by the elasticity of the spring projection 8. The opening direction of the light-collecting sheet 2 is defined by the direction of the surface of the seat 7.

In the structure shown in FIG. 3, a spring plate holder 11 is fixed to a sheet metal frame 9 holding the lamp 1 with screws 10. The lamp receiving member 4 and the light-collecting sheet 2 fitted to the lamp receiving member 4 are fitted in the U-shaped bent portion of the holder 11.
An end 12 of the holder 11 opposite to the screwed side is locked to the sheet metal frame 9, and the light-collecting sheet 2 of the receiving member 4 is sandwiched and fixed by its elasticity. The opening 13 of the light-condensing sheet in FIG. 3 faces downward, and the direction is defined by the holder 11.

At both ends of the light-condensing sheet 2 in FIGS. 2 and 3 , notches 14 are provided at both ends of the edge of the opening as shown in FIG. Is located in the notch 14.

As shown in FIGS. 5 to 7, the condensing sheet 2 is made of a strip-shaped white resin sheet having a high reflectance and a polygonal line 1.
The light-condensing sheet 2 is formed by bending at 5 and 15 to have a U-shaped cross section. A slit 17 is provided in the central portion 16 in the longitudinal direction of the light-collecting sheet 2 as shown in FIGS. By providing a recess 18 at the center of the edge of the opening of the light-condensing sheet, the light at the center of the light source lamp 1 escapes from the slit 17 or the recess 18, and
The illuminance of the reading unit 19 in the longitudinal direction can be made uniform.

That is, when the reading section 19 is illuminated by the light source lamp 1, the illuminance at the central portion in the longitudinal direction of the tube increases. However, the provision of the slits 17 or the concave portions 18 reduces the light collection rate at the central portion of the tube. As a result, the illuminance at the center of the tube decreases, and the reading unit 19 is uniformly illuminated as a whole in the tube axis direction as shown in FIG. 5 shows an example in which a slit 17 is provided on the side wall surface of the light-collecting sheet 2, and FIG. 6 shows an example in which a slit 17 is provided on the back surface of the light-collecting sheet.

FIG. 9 shows an example of a transmission original reading apparatus provided with a condensing glass plate 20. Condensing glass plate 20
As shown in FIG. 10, is a strip shape elongated in the tube axis direction of the light source lamp 1, and the end surface 21 on the light source lamp side and the end surface 22 on the reading unit side are polished surfaces.

Such a condensing glass plate 20 is particularly effective when a light source lamp 1 having a normal diameter is used as the transmissive reading light source lamp 1. Light emitted from the central portion of the light source lamp 1 is shown in FIG.
As shown in FIG. 3, the light is guided by the light condensing glass plate 20 to the original reading unit 19 without being scattered.
Light obliquely entering the document reading unit from the side of
Is reflected by the side surface 25 of the light-condensing glass plate and is not irradiated to the reading unit 24 below the original, and therefore, it is possible to suppress disturbance light generated by light obliquely passing through the reading unit of the original.

The condensing glass plate 20 can be made to have a mirror surface by depositing aluminum on the side surface 25, thereby reading the light incident from the end surface 21 on the side of the light source lamp more reliably as shown in FIG. The portion 19 can be guided, and the light incident on the side wall of the condensing glass plate 20 is completely reflected, so that the generation of disturbance light can be further reduced.

FIG. 13 shows a state of reading a transparent original.
This is an example in which a disturbance light blocking glass plate 26 having the same structure as the condensing glass plate 20 is arranged on the optical path of the reading light after passing through the document. The disturbance light blocking glass plate 26 has a main purpose of preventing the reflected light from entering the reading unit 24, and has a dimension L in the optical path direction of the reading light larger than that of the condensing glass plate 20 so that the reading light can be reduced. Preferably, 27 is guided by the disturbance light blocking glass plate 26 as long as possible. It is particularly preferable to adopt a structure in which the side surface of the disturbance light blocking glass plate 26 has a mirror surface formed by vapor deposition of aluminum, so that the light reflected inside the reading unit 24 is disturbed light as the disturbance light.
8 can be more reliably prevented.

The structure shown in FIG. 13 in which the structure shown in FIG. 13 is used together with the structure shown in FIG. 1 is particularly effective when a small-diameter light source lamp is used as the light source lamp 1 for transmission reading.

[0034]

According to the present invention described above, it is possible to prevent the reading quality from deteriorating due to fluctuations in the amount of light and disturbance light when reading an original in an original reading apparatus, particularly an original reading apparatus capable of reading a transparent original. effective.

Further, according to the present invention, it is possible to achieve the above-mentioned effects with a simple structure, and to provide a transparent document reading apparatus which is capable of high-quality reading, is lightweight, and is easy to operate at a low cost. There is.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a main part of a first embodiment.

FIG. 2 is a side view showing a first example of a fixing structure of a light-collecting sheet.

FIG. 3 is a side view showing a second example of the fixing structure of the light-collecting sheet.

FIG. 4 is a side view showing a cutout at an end of the light-collecting sheet .

FIG. 5 shows a first light-condensing sheet having a shading action.
Perspective view showing an example

FIG. 6 shows a second light-condensing sheet having a shading action.
Perspective view showing an example

FIG. 7 shows a third light-condensing sheet having a shading action.
Perspective view showing an example

FIG. 8 is an explanatory diagram of a shading action.

FIG. 9 is a side view of a main part of the original reading apparatus provided with a light condensing glass plate.

FIG. 10 is a perspective view of a condensing glass plate.

FIG. 11 is an explanatory diagram of an operation of a light-collecting glass plate.

FIG. 12 is an explanatory view of the operation of a light-collecting glass plate having aluminum deposited on the side surface.

FIG. 13 is a side view of a main part of the document reading apparatus provided with a disturbance light blocking glass plate.

FIG. 14 is a side view of a main part showing an example of a conventional document reading apparatus.

FIG. 15 is an explanatory diagram of a change in illuminance when a small-diameter light source lamp is used.

FIG. 16 is an explanatory diagram of a conventional shading structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Small-diameter light source lamp 2 Condensing sheet 3 Document 4 Receiving member 6,9 Frame 7 Seat 11 Holder 13 Opening 17 Slit 18 Concave 19 Reading part 20 Condensing glass plate 21,22 End face 26 Disturbance light blocking glass plate 27 Reading light 28 Image sensor 34 Imaging lens 35 Reflector

 ────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-91364 (JP, A) JP-A-4-63057 (JP, A) JP-A-4-156166 (JP, A) JP-A-5-156 199366 (JP, A) JP-A-5-207230 (JP, A) JP-A-6-291940 (JP, A) JP-A-63-108332 (JP, A) JP-A-2-166880 (JP, A) Japanese Utility Model Showa 58-93067 (JP, U) Japanese Utility Model Showa 60-21737 (JP, U)

Claims (4)

(57) [Claims] 1. A document reading apparatus using a small-diameter light source lamp (1) as a lamp for illuminating a read document, wherein the small-diameter light
Slightly smaller than the diameter of the source lamp connected to both ends of the source lamp
According to the width of the square receiving member (4) with a wide width
Light collection made of white resin sheet refracted and formed in a U-shaped cross section
Read the sheet (2) and the opening (13) of the condensing sheet to read the original (3).
In the state where both ends are covered with the receiving member toward the taking position (19),
Covered both ends provided on the lamp holding frames (6, 9)
Hold the seat (7) and the spring protrusion (8) or holder (11)
Document reading apparatus characterized by there. 2. The document reading apparatus according to claim 1, wherein the light-condensing sheet has a longitudinal slit at a central portion of the wall surface in the longitudinal direction. 3. The document reading device according to claim 1, wherein the small-diameter light source lamp of the document reading device according to claim 1 is a light source lamp for transmission reading. 4. An original reading apparatus provided with a small-diameter light source lamp (1) for transparent reading, a reading position (19) of an original and a reading light (2).
7) between the reflecting mirror (35) and the imaging lens (34) in the main scanning direction of the image sensor (28) having the end faces (21, 22) on the original side and the reflecting mirror or the imaging lens side polished. An elongated disturbance light blocking glass plate (26) scans the document side end face (22) at the reading position (19).
The document reading device according to claim 1, wherein the document reading device is arranged close to the document reading device.