JPS614360A - Picture input device - Google Patents

Abstract

PURPOSE:To obtain a high performance device which is made more small-sized and has a smaller number of parts, by providing a high precision and a high reliability with simpler mechanisms and using a linear motor, whose occupied area is small, as the driving mechanism. CONSTITUTION:A linear motor 1 is constituted including an angular bar-shaped stator 2 and a needle 3, and the stator 2 is fixed to the center part of a casing 5 so that it is parallel with the surface of an original and the original subscanning direction. An image pickup unit 6 consists of a light source 7, a light leading system 8, and a light source conversion unit 9 including a solid-state image pickup element and a signal processing circuit, and this unit 6 is fixed to the needl 3 so that it is parallel with the original surface and is orthogonal to the original subscanning direction. Since transmission mechanism parts such as wires, pulleys, gears, etc. and many mechanism parts for supporting or fixing them are unnecessary for driving of the image pickup unit and spaces occupied conventionally by leading-around of wires, installations of pulleys and gears, etc. are unnecessary, the device is made more small-sized and light- wright. The positon precision, the linearity, the reproducibility, etc. are dependent upon the precision of the linear motor itself and the capacity of an electronic circuit driving and controlling the linear motor because the image pickup unit is directly driven linearly, and therefore, the device is not affected by the conventional frictional loss or the like generated by wire expansion/contraction and transmission mechanisms, and the reduction of the life and the noise caused by them are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image input device used in image input systems of information processing equipment such as input terminals for computers, electronic filing systems, and intelligent copy machines. .

Conventional Structure and Problems There are two types of image input devices that mechanically scan originals: cylindrical scanning systems and flat scanning systems. In the cylindrical scanning method, documents are wound one by one around a cylinder, and main scanning is performed by rotating the cylinder, and sub-scanning is performed by relative movement of the scanning head and the cylinder in the axial direction of the cylinder. However, this method is limited to sheet-like originals, and problems such as separation of the original due to centrifugal force occur. Planar scanning devices use a method that moves the original in a flat state for sub-scanning, and there are methods that perform main scanning by sweeping the light spot and methods that use optical fibers arranged in a straight line, but none of these methods can be used. , which has the drawbacks of being mechanically complex and occupying a large space.

A solid-state scanning method is similar to the plane scanning method. This system inputs images using solid-state image sensors arranged on the object. Main scanning is performed by electronically switching the image sensors, and sub-scanning is performed between the imaging section containing the image sensor array and the image on the document. It is mechanically simple, takes up little space, and can be used not only for sheet-like documents but also for bound documents such as books.

However, conventional solid-state scanning image input devices use a drive mechanism that uses a rotary motor to move the imaging unit linearly through transmission members such as gears, rollers, pulleys, and wires. It was the most common.

However, when using such a drive mechanism, there is a certain limit to the performance that can be obtained, as described below, and if you try to exceed the limit, it will be technically and cost-effective. It was inevitable that we would be faced with a suddenly difficult situation.

The first problem is physical accuracy related to position accuracy, linearity, and reproducibility. For example, there is always a certain amount of backlash and dead zone in the gear, and there is slip in the trigger. Also, the longer the wire 1', the more its expansion and contraction will have a negative effect on accuracy.

The second problem is reliability, such as durability and lifespan.

The above-mentioned transmission system includes members that transmit force through frictional resistance, and uses rotating members such as rollers to bend the wire, so wear inevitably progresses in each part and causes deterioration. It is inevitable that something will happen. In addition, the probability of wire deterioration and disconnection accidents is particularly high.

The third problem is noise. As mentioned above, the conventional system transmits the rotational force of a rotary motor through numerous transmission members. Iゎkaya(、transmit □directly、drive、□16 materials.

Many parts generate quite loud noise. In particular, the resonance noise of the wire and the rotation noise of the rollers are relatively loud. As a result, the quality of the equipment is often significantly impaired.

Due to the limited accuracy and reliability of the drive mechanism as described above, conventional performance such as resolution during image reading has been limited to a certain extent.

OBJECTS OF THE INVENTION The present invention, in order to eliminate the above-mentioned conventional problems, employs as a drive mechanism a linear motor that has a simpler mechanism, has high precision and high reliability, and occupies a small volume. Kokichi's objective was to provide an image input device that was smaller, had fewer parts, and had higher performance.

Composition of the Invention The image input device of the present invention includes a linear motor and a solid-state image sensor for reading image information, and is basically arranged in such a way that the stator of the linear motor is arranged in the center of the housing. .

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a specific example of the configuration of an image input device according to the present invention. In the figure, a linear motor 1 has a square bar-shaped stator 2. The stator 2 includes a movable element 3, and the stator 2 is fixed to the center of the housing 5 so as to be parallel to the document surface and the document sub-scanning direction. The imaging unit 6 includes a light source 7.
Light guiding system 8. It is composed of a photoelectric conversion unit 9 including a solid-state image sensor and a signal processing circuit, and is fixed to the movable element 3 so as to be parallel to the document surface and orthogonal to the document sub-scanning direction.

Further, in the figure, 48 is a bearing rotatably attached to the imaging unit 6, and 4b is a running guide attached to the housing 5 along the sub-scanning direction so that the bearing 4a can run.

As is clear from FIG. 1, the present invention eliminates the need for transmission mechanism parts such as wires, pulleys, and gears to drive the imaging unit, and eliminates the need for many mechanical parts to support or fix them. Since the space occupied by wiring, pulleys, gear installation, etc. is eliminated, the device can be made smaller and lighter. In addition, since the imaging unit is directly driven linearly, positional accuracy, linearity, reproducibility, etc. mainly depend on the accuracy of the linear motor itself and the performance of the electronic circuit for driving and controlling it. It is not affected by the expansion and contraction of the wire or the friction loss generated in the transmission mechanism, and there is no reduction in life or generation of noise due to these causes.

On the other hand, in a configuration in which a linear motor is arranged at one end of the imaging unit and another travel auxiliary member is arranged at the other end, during driving, the movable part of the imaging unit and the linear motor may Since force tends to concentrate on the upper joint, it is necessary to design the joined parts to be extremely strong, which is disadvantageous in terms of cost and weight. Furthermore, the weight balance of the device tends to be biased to one side.

Furthermore, a configuration in which one linear motor is installed at each end of the imaging unit has the advantage that the linear motor can be made smaller than the above configuration, and it is easier to balance the forces. It is disadvantageous in terms of weight compared to driving, the number of mechanical parts increases, and depending on the type of motor, two electronic circuits for driving may be required, which is disadvantageous in terms of cost.

For the above reasons, by arranging the linear motor in the center of the housing and placing the imaging unit on the movable part near its center of gravity, it is possible to connect the imaging unit and the movable part when driving. Since the force applied to the parts is reduced, it is possible to simplify the joining parts, the weight balance of the entire device becomes even, the number of mechanical parts is reduced and the weight can be reduced, and the drive circuit is also unified. It is also cost-effective, as it only requires a stand.

FIG. 2 is a side view of the movable element 3 and the imaging unit 6 fixed to the movable element 3. The movable element 3 is attached to a movable element frame 10, and the movable element frame 10 includes rollers that maintain a constant slight gap between the stator 2 and the movable element 3 and guide the movable element 3 smoothly. A guiding means 11 such as the one shown in FIG.

Next, the basic functions of the imaging unit 6 will be explained with reference to FIG. 2. The light emitted from the light source 7 passes through the transparent glass plate 12 for placing the document, is reflected on the document surface 13, passes through the light guide system 8, enters the solid-state image sensor 9a, is converted into an electrical signal, and is further sent to the signal processing circuit 9b. It is output after passing through.

Note that the type of motor has no bearing on the gist of the present invention.

Further, although the motor control method is not mentioned in the description of the embodiment, a well-known electronic control circuit technique can be used for this.

Effects of the Invention As is clear from the above explanation, the image input device of the present invention has the following advantages by adopting the linear motor as the drive source and further arranging the stator of the linear motor in the center of the housing. You can get the desired effect.

(1) Since the imaging unit including the imaging element is driven directly and linearly, positional accuracy, reproducibility, durability, and reliability that could not be obtained with conventional systems that use a rotary motor and transmission member can be obtained. . In addition, noise can also be reduced.

(2) There is no transmission member, the drive mechanism is concentrated around the stator, and the occupied volume is small, so the number of parts is small and the device can be easily miniaturized.

(3) By placing the linear motor in the center,
It is mechanically simpler than arranging a linear motor at one end of the imaging unit and another traveling member at the other end, and it is also simpler than arranging one linear motor at each end of the imaging unit. The number of mechanical parts and the number of driving electronic circuit parts are reduced.

As a result of the above effects, it is possible to achieve performance such as resolution during image reading, which was difficult to achieve with conventional methods, and the entire apparatus can be made smaller, lighter, and lower in cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of an image input device of the present invention, and FIG. 2 is a side sectional view of the main part of FIG. 1. 1...Linear motor, 2...Stator,
3...Mover, 6...Imaging unit,
7... Light source, 8... Light guide system, 9...
...Photoelectric conversion unit, 9a...Solid-state image sensor, 9b...Signal processing circuit Name of agent: Patent attorney Toshi Nakao, male, one idiot. Figure 2 tt (10-Qb etc.

Claims (1)

[Claims] An imaging unit including an image sensor array arranged parallel to a document surface and along the document main scanning direction, a light source, and an optical system that focuses light reflected from the document by the light source onto the image sensor array. A stator is fixed to the center of the housing parallel to the document surface and along the document sub-scanning direction perpendicular to the document main-scanning direction, and the imaging unit is mounted and fixed directly in a straight line. An image input device characterized by comprising a linear motor including a movable element that is movable along the movable element.