JPH01293755A - Original reader - Google Patents

Abstract

PURPOSE:To obtain a clear picture and to reduce the cost of the title device by directly bringing an image sensor through a roller into contact with a transparent plate and moving the image sensor with one sliding shaft and one belt. CONSTITUTION:While an image sensor 2 moves, the sensor 2 is in an energized state in the direction to a transparent plate 1 by the function of a spring 20. Thus, rollers 13 can be always kept in a contacted state on the rear surface of the transparent plate 1, and the distance between the sensor 2 and the transparent plate 1 can be always kept in a fixed distance. Further, since both a sliding shaft 22 and a belt 23 are provided approximately at the center of the sensor 2, and the rollers 13 in contact with the transparent plate 1 are provided for both edges of the sensor 2, the possibility that the sensor 2 generates a forward and backward deflection with the part of a sliding bearing 21 as its center is minimized so that the possibility can be ignored. Thus, the clear picture can be obtained, which is focused all the time, the number of parts can be minimized, and the cost of the device can be lowered.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a structure for moving a document reading device, particularly a one-dimensional image sensor having the same length as the document reading width, in a direction perpendicular to the reading width. Regarding.

(Prior Art) Figure 2 shows an outline of a conventional document reading device in which a document is placed on a transparent plate and an image sensor provided on the back side of the transparent plate is moved. It is placed face down on the transparent plate l. The transparent plate 1 has a uniform flat surface and a constant thickness. On the back side of the transparent plate 1, there is a transparent plate l
An image sensor 2 that is long in the width direction is provided. The length of this image sensor 2 becomes the document reading width. This image sensor 2 is called a one-dimensional image sensor 2, and is provided with an LED array (not shown) in the length direction. This L
The ED array illuminates the reading surface of the document. The illuminated area is formed as a line in the length direction of the one-dimensional image sensor 2. Each point on the illuminated line corresponds to each LED making up the LED array. Each of these points reflects image information as white or black depending on the image on the reading surface.

This light information is imaged onto the sensor surface by a SELFOC lens (not shown) provided parallel to the LED array. This sensor consists of a photoelectric conversion element and converts white or black optical information into a 1 or O electrical signal.

By operating the LED array in this manner, main scanning in the length direction of the one-dimensional image sensor 2 is performed.

One-dimensional image sensor 2 is held by sensor holder 3. Both ends 4 of this sensor holder 3 are each fixed in the middle of a wire 5. Two wires 5 are provided at both ends of the sensor holder 3 and run in a direction perpendicular to the length direction of the one-dimensional image sensor 2. These wires 5 are each wound around two wire pulleys 6, and these wire pulleys are rotatable.

Note that both ends of the one-dimensional image sensor 2 are supported by rails 7. This rail 7 is for moving the one-dimensional image sensor in the sub-scanning direction orthogonal to the main scanning direction.

One of the wire pulleys 6 (
A) is linked to a belt pulley 9 by a drive shaft 8, and this belt pulley 9 is rotated by another belt pulley 11 via a belt 10. This other belt pulley 11 is driven by a pulse motor 12
The driving force for rotation is given by.

Note that although the above conventional example shows one in which both ends of the one-dimensional image sensor 2 are supported by the rails 7, other conventional examples use other guides such as a guide shaft. Further, although the wire 5 is shown as a device for moving the one-dimensional image sensor 2, other conventional examples use a flexible long material such as a belt.

(Problems to be Solved by the Invention) However, in these conventional examples, two wires 5.
The number of parts such as the two rails 7 and the four wire pulleys 6 is large, leading to an increase in the cost of manufacturing the device. Furthermore, since parts such as the rail 7 and the wire 5 are concentrated on both ends of the one-dimensional image sensor 2, space in the main scanning direction is required inside the device, and the overall device tends to become large.

Furthermore, it is necessary to adjust the distance between the guide such as the rail 7 and the transparent plate 1 so that the focus of the Selfox lens of the one-dimensional image sensor 2 matches the surface of the transparent plate 1, and this adjustment work is troublesome. It was something. In particular, when the transparent plate 1 itself is warped, this adjustment is difficult and the focal point becomes blurred.

(Means for Solving the Problems) A document reading device of the present invention has a one-dimensional image sensor brought into direct contact with a transparent plate via a light friction member, and one guide provided approximately at the center of the one-dimensional image sensor. It has a structure in which it is moved by a single long flexible member.

More specifically, it includes a transparent plate for placing an original, a one-dimensional image sensor provided on the back side of the transparent plate, which has the same length as the original reading width, and performs main scanning in the length direction; A light friction member provided at both ends of the image sensor and in contact with the transparent plate; a spring biasing the one-dimensional image sensor toward the transparent plate; a senna holder supporting the spring; and a senna holder provided approximately in the center of the sensor holder. a sliding part, a guide that is in contact with the sliding part and guides the sensor holder in a sub-scanning direction perpendicular to the main scanning direction, and a flexible part that is partially fixed approximately at the center of the sensor holder. It is equipped with a long material, a pulley that can be rotated by winding the flexible long material, and a motor that rotates this pulley.

(Function) Since the one-dimensional image sensor can be moved using one guide and one long flexible member, the number of parts can be reduced. Long lumber can be eliminated. Further, by directly contacting the transparent plate with the light friction members provided at both ends of the one-dimensional image sensor, it becomes easy to adjust the focus of the one-dimensional image sensor to the surface of the transparent plate. Especially if the memorial board itself is warped 1.
Since the one-dimensional image sensor moves along the curve of the warp, it is possible to prevent the image from becoming out of focus.

(Embodiment) An embodiment of the present invention is shown in FIG. 1. The same parts as in FIG. 2 showing the conventional example are designated by the same numbers and the explanation thereof will be omitted.

At both ends of the one-dimensional image sensor 2, smoothly rotating rollers 13 are provided as light friction members. A pair of rollers 13 are provided at each end of the one-dimensional image sensor 2. The rollers 13 are attached to a trolley 14, and are in contact with the back side of the transparent plate 1 so as to be able to move with small friction. This roller cart 14 is fixed to a sensor mounting bracket 15, and the sensor mounting bracket 15 is connected to the one-dimensional image sensor 2.
It is fixed to the top of both ends of the main body.

The sensor mounting bracket 15 has two flanges 16 at the front and rear in the moving direction of the one-dimensional image sensor 2.

It is formed. A hole is provided in this flange portion 16, and a screw 1 having a diameter smaller than that of the chain hole is inserted into this hole.
7 has been inserted. The lower end of this screw 17 is threaded and screwed into the flange portion 19 of the sensor holder 18 and fixed thereto. A coil spring 20 is present on the outer periphery of the screw 17, and the upper and lower ends of the coil spring 20 are connected to the sensor mounting bracket side 15 or the sensor holder side 18.
is in contact with flange m16.19. As a result, the one-dimensional image sensor 2 is urged toward the transparent plate 1 by the coil spring 20. Note that the outer peripheral surface of the screw 17 with which the coil spring 20 comes into contact is a smooth surface.

The sensor holder 18 is provided to cover the lower part of the one-dimensional image sensor 2, and has a very smooth sliding bearing 21 in the center. One sliding shaft 22 guides the one-dimensional image sensor 2 using the bearing 21 as a sliding part. This sliding shaft 22 has a smooth surface and is provided parallel to the transparent plate 2 in the sub-scanning direction perpendicular to the main-scanning direction, that is, in the moving direction of the one-dimensional image sensor.

In this embodiment, a belt 23 is used as a flexible long member for moving the one-dimensional image sensor 2. A portion of this belt 23 is fixed near the approximate center of the sensor holder 18. That is, this fixed position is near the sliding bearing 21. The length of the belt 23 is more than twice the length of the document reading range in the sub-scanning direction. Belt pulleys 24 are present at both ends of the belt 23. The belt 23 is wound around these belt pulleys 24, and one of the two belt pulleys 24 (A) is interlocked with the other belt pulley 9 by a drive shaft 8. This belt pulley 9 is connected to a pulse motor 12 via another belt 10 and another belt pulley 11 as in the past.
The driving force is transmitted and rotated. The pulse motor 12 is capable of supplying the torque and rotational speed necessary to move the one-dimensional image sensor 2 at the required speed and the required distance.

The operation of the above embodiment will be explained. That is, a series of sub-scanning operations during document reading are performed as follows. First, the LED array is turned on to linearly illuminate the reading surface of the document in the main scanning direction.Then, the pulse motor 12 is driven to move the one-dimensional image sensor 2 by the required amount. This necessary amount is called the sub-scanning movement amount. The driving force of the pulse motor 12 is applied to the belt pulley 1.
1, bell) 10, and belt pulley 9 to the drive shaft 8. When the drive shaft 8 rotates, the pulley 24 (A) fixed to the drive shaft 8 rotates.
The belt 23 meshing with (A) moves in the sub-scanning direction. As the belt 23 moves, the one-dimensional image sensor 2 moves along the sliding shaft 22 via the sensor holder 18 which is fixed to a part of the belt 23.

While the one-dimensional image sensor 2 is moving in this way,
The one-dimensional image sensor 2 is biased toward the transparent plate 1 by the action of a coil spring 20. As a result, the roller 13 can always be kept in contact with the back surface of the transparent plate 2, and therefore the distance between the one-dimensional image sensor 2 and the transparent plate 1 is always kept constant. Therefore, as long as the roller 13 is securely attached to the one-dimensional image sensor 2, it is easy to keep the one-dimensional image sensor 2 focused on the surface of the transparent plate 1 at all times.

In addition, a sliding shaft 22 that guides the one-dimensional image sensor 2
Only one belt 23 is provided for moving the one-dimensional image sensor 2 and the one-dimensional image sensor 2. However, both the sliding shaft 22 and the belt 23 are located approximately at the center of the sensor holder 18, that is, approximately at the center of the one-dimensional image sensor 2. The rollers 13, which are light friction members that contact the transparent plate 1, are provided at both ends of the one-dimensional image sensor 2, so that the one-dimensional image sensor 2 can move forward and backward around the sliding bearing 21. The possibility of occurrence of runout can be made so small that it can be ignored.

(Other Examples) In the above example, the belt 23 was used as a flexible long material for moving the one-dimensional image sensor 2.
Other embodiments may also use wire. In this case, it is used in combination with a retractable wire boolean. In addition, although the rollers 13 were used as light friction members provided at both ends of the one-dimensional image sensor 2 and in contact with the transparent plate, in other embodiments, a member with a small friction coefficient such as high-density polyethylene may be used. . Such a member will be used as a sliding member that slides on the transparent plate l.

Although the coil spring 20 is used as a spring for biasing the one-dimensional image sensor 2, other elastic bodies such as a plate spring can be used in other embodiments.

Further, although the sliding shaft 22 having a circular cross section is used as a guide for guiding the sensor holder 18, in other embodiments, a shaft having a non-circular cross section may be used as a guide.

Furthermore, the sliding portion 21 provided on the sensor holder 18 side uses a sliding bearing 21 that surrounds a sliding shaft 22 that is a guide, but in other embodiments, the sliding portion may simply engage with the guide. You can also do it.

(Effects of the Invention) According to the document reading device of the present invention, it is possible to reduce the number of guides, flexible long materials such as wires or belts, and therefore the number of pulleys, etc. can be further reduced, resulting in fewer parts. As a result, equipment costs can be reduced.

It is possible to eliminate the guides and flexible long materials (for example, wires) that were conventionally present at both ends of a one-dimensional image sensor, and the space in the main scanning direction within the device is no longer required, making the entire device more compact.

If the light friction member that comes into contact with the transparent plate is securely attached to the one-dimensional image sensor, there is no need to adjust the focus of the one-dimensional image sensor to the transparent plate surface. There is no need to adjust the distance.

Even if the transparent plate itself is warped, the one-dimensional image sensor moves along the curved surface of the warp, so a clear and focused image can always be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a document reading device showing an embodiment of the present invention, and FIG. 2 is a schematic perspective view showing a conventional device. Explanation of symbols 1...Transparent plate, 2...Image sensor,
7...Rail, 5...Wire, 6...
wire pulley. 9.11... Belt pulley, 12... Pulse motor, 13... Roller (light friction member), 20... Coil spring (spring), 18... Sensor holder, 21... Sliding bearing ( 22...Sliding shaft (guide), 23...Belt (flexible long material), 24...Belt pulley

Claims (1)

[Claims] A transparent plate for placing a document, a one-dimensional image sensor that has the same length as the document reading width provided on the back side of the transparent plate and performs main scanning in the length direction, and a one-dimensional image sensor. light friction members provided at both ends and in contact with the transparent plate;
a spring that biases the one-dimensional image sensor toward the transparent plate; a sensor holder that supports the spring; a sliding part provided approximately in the center of the sensor holder; One guide guides in the sub-scanning direction perpendicular to the scanning direction, one flexible long material partially fixed at approximately the center of the sensor holder, and a pulley that can rotate around the flexible long material. A document reading device equipped with a motor that rotates a pulley.