JP2572307B2 - 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 such as a wide-width reading unit or a wide-width printer unit in which a plurality of line sensors are arranged in two rows in a staggered manner and supported by a main body frame, and in particular, a positioning mechanism between licensors. About.

[0002]

2. Description of the Related Art FIG. 4 shows an outline of a conventional document reading apparatus of this kind. First, second and third three line sensors 1
When the line sensors 2 and 3 are arranged in two rows in a staggered manner on the main body frame 4, both ends of each of the line sensors 1, 2 and 3 are sandwiched between the fixed bracket 5 and the movable bracket 6 and the line sensors 1 and 2 are -The positioning and fixing were performed on the body frame 4 for every three. The movable bracket 6 has a horizontally long groove 8 through which a mounting screw 7 penetrates, is slidable in the main scanning direction A with respect to the main body frame 4, and is urged by a spring 9 toward the fixed bracket 5. The expansion, contraction caused by temperature changes of the sensors 1, 2, 3 and the main body frame 4 are absorbed. Since there is a shift of n pixels between the line sensors 1 and 3 and the line sensor 2, this is corrected by the memory.

[0003]

However, such a structure has the following problems. That is, generally, the line sensors 1, 2, and 3 are made of ceramic, and the main body frame 4 is made of a metal such as aluminum or iron, and they have different coefficients of thermal expansion. A pixel shift occurs in the main scanning direction A and the sub-scanning direction B at a connection portion between the first and second line sensors 1 and 2.
In some cases, 2.3 was warped, bent, or damaged. When a pixel shift occurs in this way, when a document of one pixel line is read, pixels are shifted between the line sensors 1, 2, and 3 and read, resulting in an image with poor reading quality and output to a printer. The case is equally bad.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a pixel shift between line sensors with respect to a temperature change to improve reading quality.
Another object of the present invention is to make it possible to easily adjust the connection between the line sensors with a simple configuration.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a document reading apparatus in which a plurality of line sensors are arranged in two rows in a staggered manner and supported on a main body frame, and a connecting member slides in the main scanning direction on the main body frame. A main scanning direction positioning member that is mounted as possible and that positions the adjacent line sensors in the main scanning direction between the adjacent line sensors is provided. The connection member may further include a sub-scanning direction positioning member for positioning the adjacent line sensors in the sub-scanning direction. It is preferable that both positioning members in the main scanning direction and the sub-scanning direction are constituted by eccentric cams.

[0006]

Since the adjacent line sensors are positioned relative to each other via the connecting member slidable in the main scanning direction with respect to the main body frame, the line sensors can be made independent of the deformation due to the temperature change of the main body frame.

[0007]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. 1 and 2, light sources 11 and 12 are arranged in a box-shaped main body frame 10 in parallel, and
Are illuminated through the protective glass 14. On the upper surface of the main body frame 10, slopes 15 and 16 are formed, which are inclined at a predetermined angle in directions opposite to each other, and on one slope 15 are first and third line sensors 17 and 1.
9, a second line sensor 18 is provided on the other slope 16. These line sensors 17, 18, and 19
Are arranged in a staggered manner such that the light receiving portions 17a, 18a, and 19a are parallel. Further, in the elongated holes 20 and 21 provided in the main body frame 10, the same-magnification focusing rod lens arrays 22 and 23 corresponding to the line sensors 17, 18 and 19 (the ones corresponding to the first line sensor 17 (Not shown), and the line sensors 17, 18, and 19 are arranged such that the image on the same reading line 24 is received by the light receiving portions 17a and 1 of each of the line sensors 17, 18, and 19.
Adjustment is performed as described later so that the images are formed erectly on 8a and 19a.

The first line sensor 17 has a main scanning direction A
Is positioned by pressing one end thereof with a pressing spring 25 and pressing the other end against the reference projection 26 of the main body frame 10. In the sub-scanning direction B, the fixing screw 2
7, a pair of eccentric cams 28, each of which can regulate rotation,
The pair of pressing springs 29 are pressed and pressed against each other to position both ends individually so as to be adjustable, so that the light receiving line of the light receiving unit 17a coincides with the same reading line 24.

The second and third line sensors 18 and 19 also have fixing screws 30 at the opposite ends.
Eccentric cam 31 and pressing spring 3 that can regulate rotation with
2 and are positioned in the sub-scanning direction B so as to be adjustable, but the ends on the opposite sides are mutually positioned by the following mechanism.

A connection member 33 is mounted on the main body frame 10 so as to cover the opposite ends of the second and third line sensors 18 and 19 from above. The connection member 33 has a pair of guide slots 36 through which a pair of pins 35 implanted on the upper surface of the main body frame 10 are slidable in the main scanning direction A. Further, the connection member 33 includes the pressing spring 3
7 is urged toward the second line sensor 18 side. Eccentric cams 38 and 39 for positioning the second and third line sensors 18 and 19 in the main scanning direction A, respectively, and subordinates of these line sensors 18 and 19 are provided on the back surface (lower surface) of the connection member 33. The eccentric cams 40 and 41 for positioning in the scanning direction B are fixed screws 42 respectively.
It is attached so that rotation can be regulated with. The eccentric cam 40 corresponds to a pressing spring 43 provided on the main body frame 10, and the eccentric cam 41 similarly corresponds to a pressing spring 44 provided on the main body frame 10. The eccentric cam 38 sandwiches the second line sensor 18 in the main scanning direction A with an eccentric cam 45 provided on the main body frame 10, and the eccentric cam 39.
Holds the third line sensor 19 with the pressing spring 46 provided on the main body frame 10.

The eccentric cam 45 is installed in the vicinity of the reference projection 26, and its rotation can be restricted by a fixing screw 46. In addition, all eccentric cams 28, 31, 38,
39, 40, 41, and 45 are arranged near the center line of the main body frame 10. The connecting member 33
Is urged to one side in the sub-scanning direction by a pressing spring (not shown) so as not to swing in the sub-scanning direction.

The positioning of the second line sensor 18 is performed as follows. While setting the first line sensor 17 at the reference position in the main scanning direction A as described above,
After adjusting the position in the sub-scanning direction B, a jig having a reference dimension is set on the reading surface, and the eccentric cam 45 and the eccentric cam 38 adjust the position of the second line sensor 18 in the main scanning direction. One end 18b of the light receiving portion 18a of the sensor 18 is made to coincide with the other end 17b of the light receiving portion 17a of the first line sensor 17 in the main scanning direction. The position in the sub-scanning direction is adjusted by the eccentric cam 31 and the eccentric cam 40 so that the light receiving line of the light receiving unit 18a coincides with the same reading line 24.

The positioning of the third line sensor 19 is performed as follows. After the position of the second line sensor 18 is adjusted as described above, the position of the third line sensor 19 in the main scanning direction is adjusted by the eccentric cam 39, and the line sensor 19 is adjusted.
One end 19b of the light receiving portion 19a of the second line sensor 1
8 and the other end 18c of the light receiving section 18a in the main scanning direction. The position in the sub-scanning direction is adjusted by the eccentric cam 41 and the eccentric cam 31, so that the light receiving line of the light receiving unit 19a coincides with the same reading line 24.

The above adjustment is performed at normal temperature. The main body frame 10 is generally made of lightweight high-strength aluminum, whereas the line sensors 17, 18, and 19 are generally made of ceramic, and the light-receiving portions 17a, 18a, and 19 are provided.
a is composed of silicon. Therefore, the main body frame 10
Since the thermal expansion coefficients of the main body frame 10 and the line sensors 17, 18, and 19 are different from each other, the body frame 10 expands more than the line sensors 17, 18, and 19 with respect to a temperature change. Further, since the length of the main body frame 10 is long (for example, about 1
m), the expansion ratio in the main scanning direction is larger than that in the sub scanning direction.

In response to such a change due to temperature, the present apparatus uses a second line sensor 18 and a third line sensor 19.
Since the mutual position adjustment in the main scanning direction A and the sub-scanning direction B is performed via the connecting member 33 slidable in the main scanning direction with respect to the main body frame 10, the contraction of the main body frame 10 due to heat is reduced. Absorbed by the line sensor 18
・ Effect on 19 can be avoided. Also, the main body frame 10
The first line sensor 17 is positioned in the main scanning direction with reference to the reference projection 26 provided on the reference projection 2.
6 near the eccentric cam 4 for the second line sensor 18
5, the pixel shift of the first and second line sensors 17 and 18 with respect to the temperature change can be reduced to a negligible level. Furthermore, all eccentric cams 28, 31, 38,
Since 39, 40, 41, and 45 are arranged near the center line of the main body frame 10, all the line sensors 1
With regard to 7, 18, and 19, the influence of contraction of the main body frame 10 in the sub-scanning direction can be reduced.

The line sensors 17, 18, and 19 and the connecting member 33 are prevented from floating with respect to the main body frame 10 by a lifting spring (not shown) for preventing lifting. When the line sensors 17, 18, 19 are floating, the image on the document 13 is received by the light receiving sections 17a, 18a.
Since the image is not formed on 19a, the resolution is reduced and the reading quality is deteriorated.

The rod lens arrays 22 and 23 are positioned with respect to the main frame 10 as follows (the same applies to the one corresponding to the first line sensor 17 not shown). FIG. 3 shows an example of the positioning structure for the rod lens array 22. Rod lens array 22
Both ends are urged upward by a pair of push-up springs 47, and the height with respect to the main body frame 10 is adjusted by a pair of height adjusting screws 48 so that an image is formed on the light receiving portion 18 a of the line sensor 18. The rod lens array 22 has one fixing screw 49 at the center to absorb the change due to the coefficient of thermal expansion with the main body frame 10.
Is fixed to the main body frame 10.

[0018]

According to the present invention, the following effects can be obtained. Pixel shift in the main scanning direction and the sub-scanning direction at the connection between the line sensors with respect to the temperature change can be prevented, and an image with high reading quality can be obtained. Since the position adjustment between the line sensors can be performed accurately and easily on the connecting member, the workability of the adjustment is improved. Since the adjustment accuracy between the line sensors is improved, a long document reading device using a large number of short line sensors can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an example of a document reading apparatus according to the present invention.

FIG. 2 is a sectional view taken along line II of FIG. 1;

FIG. 3 is a schematic diagram illustrating an example of a positioning structure of a rod lens array in the document reading apparatus.

FIG. 4 is a schematic plan view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Main body frame 17 1st line sensor 18 2nd line sensor 19 3rd line sensor 33 Connecting member 38 Eccentric cam for main scanning direction positioning of 2nd line sensor 39 Main scanning direction positioning of 3rd line sensor Eccentric cam 40 for positioning the second line sensor in the sub-scanning direction 41 Eccentric cam for positioning the third line sensor in the sub-scanning direction

Claims (3)

(57) [Claims] 1. A document reading apparatus in which a plurality of line sensors are arranged in two rows in a staggered manner and supported by a main body frame, a connection member is mounted on the main body frame so as to be slidable in a main scanning direction. A document reading apparatus, wherein a member is provided with a main scanning direction positioning member for positioning adjacent line sensors in the main scanning direction. 2. The document reading apparatus according to claim 1, wherein the connecting member is provided with a sub-scanning direction positioning member for positioning the adjacent line sensors in the sub-scanning direction. 3. The document reading apparatus according to claim 2, wherein the main scanning direction positioning member and the sub scanning direction positioning member are eccentric cams.