JPS62248368A - Reader - Google Patents

Abstract

PURPOSE:To adapt linear pulse motor to the movement of an optical unit or an original base in a reader by bringing the flange of the guide roller of the linear pulse motor into contact with the side surface of a fixed scale under pressing and moving. CONSTITUTION:The guide roller 27A is a cylindrical roller only for bringing into contact with the lower surface of the fixed scale 24 under rolling and the guide roller 27B has a cylindrical part 27a in contact with the lower surface of the fixed scale 24 and the flange 27b in contact with the side surface of the fixed scale 24. A magnet 32 is disposed on a fixed adaper 28 of the guide roller 27B having the flange confronting to the side surface of the fixed scale 24. The flange 27b of the guide roller 27B having the flange held by a slider 25 is pressed to the side surface of the fixed scale 24 by the attraction force of the magnet 32 and correctly travels on a fixed position to the fixed scale 24.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reading device in an information input device such as a facsimile machine, and in particular to a reading device for relatively moving a document table and an optical unit that optically reads a document on the document table. The present invention relates to a reading device using a linear pulse motor as a driving device.

2. Description of the Related Art Conventionally, a rotary motor, such as a pulse motor, is usually used as a power source in a driving device for moving an optical unit along a document table in a reading device.

On the other hand, printer head drive devices using linear pulse motors are known. A linear pulse motor is a linear pulse motor developed by developing a conventional rotary pulse motor in a straight line.As shown in Figure 4, a linear pulse motor is a fixed motor with many parallel grooves formed in a comb-like shape in its cross section. scale 1
, a slider 2 that runs along the fixed scale 1, and a guide roller 3 that is held by the slider 2 and rolls into contact with the fixed slider 1 so as to maintain a constant distance between the slider 2 and the fixed slider 1. ing. The fixed scale 1 corresponds to the stator of a conventional rotary pulse motor, and the slider 2 corresponds to the rotor.

As shown in FIG. 5, the slider 2 has electromagnets 6.7 each having a U-shaped cross section fixed to the different polarity portions of a permanent magnet 5 provided at the bottom of the table 4, and each coil of the electromagnet 6.7 The scale is moved on the fixed scale 1 by passing current in alternate directions. For example, when a current is passed through the electromagnet 6 in the child direction, the coil is wound in opposite directions between the a and b poles, so the magnetic force generated at the a pole is added to the magnetic force of the permanent magnet 5 and fixed. It takes the position closest to and facing the tooth A on the scale 1, and is in a stable state. On the other hand, the magnetic force generated at the b pole acts to cancel the magnetic force of the permanent magnet 5.

Subsequently, when a current is applied in the child direction to the electromagnet 7, the d pole and the D pole attract each other, and the slider 2 moves rightward by 1/4 of one pitch P of the teeth of the fixed scale 1.

This time, when a unidirectional current is applied to the electromagnet 6, the b pole and tooth B attract each other, and the slider 2 moves 1/4 pitch to the right.Subsequently, when a unidirectional current is applied to the electromagnet 7, The C pole and the tooth C attract each other, and the slider 2 moves further by 1/4 pitch.

Then, by passing a current in the child direction through the electromagnet 6 again, and subsequently passing a current in the same manner, the slider 2 can be sequentially moved to the right.

A linear pulse motor with this configuration has a high degree of stopping accuracy, and normally, as shown in FIG. A fixed adapter 9 is provided at the tip, and a side roller 10 held by the fixed adapter 9 is brought into contact with the side surface of the fixed scale 1 to regulate the position in the lateral direction. Note that a driven portion (not shown) such as a print head is held by a fixed adapter 9.

Problems to be Solved by the Invention As mentioned above, a rotary motor is used as a drive device in a conventional reading device, but this requires a mechanism to convert the rotation of the motor into linear motion of the optical unit. ,
Not only does this make the device complicated, but play and slip within the mechanism limit the ability to increase speed and precision.

Therefore, the inventor of the present invention came up with the idea of using a linear pulse motor used in the head drive mechanism instead of the conventional rotary motor, and fixed the scale that makes up the linear pulse motor to the frame of the device to use it as a fixed scale. The optical unit is connected to and held by a slider, and the optical unit is moved directly by the slider.

However, simply employing a conventional linear pulse motor as a driving device for an optical unit in a reading device has caused a problem in that the necessary constant speed cannot be satisfied. In other words, in order to read an image, it is necessary for the optical unit to run at a constant speed, but the linear pulse motor used in the head drive mechanism of conventional printers only controls the rise characteristics, establishment characteristics, and stopping accuracy of the slider. However, since this method does not take into account the constant speed during movement, it has not been possible to satisfy the constant speed of the optical unit movement required for document reading.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a reading device equipped with a device capable of moving an optical unit or a document table at a predetermined constant speed. purpose.

Means for Solving the Problems In order to solve the above-mentioned problems, the inventor of the present invention conducted extensive research and found that in general, in linear pulse motors, rattling occurs in the slider when excitation is switched to the slider (referred to as cogging). Although the constant speed characteristics are poor, it has been found that this cogging can be reduced by increasing the rotation speed of the guide roller. The present invention was made based on this knowledge, and among the guide rollers that are held on both sides of the slider of a linear pulse motor and run on the fixed scale in rolling contact with the fixed scale, the guide roller on one side of the slider is The flanged guide roller is equipped with a flange that contacts the side of the fixed scale, and the adapter located on the side of the flanged guide roller is equipped with a magnet facing the side of the fixed scale, and the attraction force of the magnet causes the flanged guide roller to The flange is pressed against the side of the fixed scale.

According to the above-described structure, the flanged guide roller runs with its flange in contact with one side of the fixed scale, and as a result, frictional force acts on the guide roller, making the rotation heavy and preventing the cogging of the slider. can be reduced and the constant speed characteristics can be improved.

Example Hereinafter, the present invention will be explained in detail using the drawings.

1 to 3 show a reading device according to an embodiment of the present invention, in which FIG. 1 is a side view, FIG. 2 is a front view partially sectional, and FIG. 3 is a bottom view. It is. In the same figure,
Reference numeral 11 denotes a document table, which includes a document table glass 12, a document presser 14 for pressing the document 13, and the like. This document table 11 is provided stationary at a fixed position.

15 is an optical unit that can run along the document table 11;
Inside is a light source 16 such as a fluorescent lamp, a reflecting mirror 17, and a condensing lens 1.
8, a reading element 19, a drive circuit 20, etc. 21
is a linear pulse motor that constitutes a drive device that drives the optical unit 15. The linear pulse motor 21 is
A fixed scale 24 fixed to the base 22 of the reading device via a fixed stand 23, a slider 25 running along the lower surface of the fixed scale 24, a guide roller shaft 26 attached to the slider 25, and a guide roller shaft 26 attached to the guide roller shaft 26. It has guide rollers 27A, 27B, etc. which are rotatably held and roll into contact with the lower surface of the fixed scale 24. The optical unit 15 is fixedly held on the guide roller shaft 26 by a fixed adapter 28, a grip 29, etc. As can be clearly seen from FIG. 2, the fixed scale 24 of this embodiment is formed of a fixed scale main body 24A and a vibration damping member 24B having a U-shaped cross section attached thereto. Of course, the vibration damping member 24
B may have a flat plate shape.

One guide roller 27A is a cylindrical roller that rolls into contact with the lower surface of the fixed scale 24, while the other guide roller 27B contacts the cylindrical portion 27m that contacts the lower surface of the fixed scale 24 and the side surface of the fixed scale 24. It is composed of a flanged roller having a flange 27b. Fixed adapter 28 adjacent to flanged roller 27B
A spacer 30 of a predetermined size is inserted between the guide roller 27B and the position of the guide roller 27B relative to the center of the optical unit 15.
In particular, the flange 27b is positioned 5se so that the contact surface with the fixed scale 24 is at a predetermined position. As a result, when the flange 27b of the guide roller 27B is brought into contact with the side surface of the fixed scale 24, the optical unit 1
5 is fixed scale:.

24 at a predetermined position. Note that spacers 31 are also inserted between the guide roller 27B and the slider 25, between the slider 25 and the other guide roller 27A, and between the guide roller 27A and the fixed adapter 28, but the dimensions of these spacers 31 are as follows. It's not that important.

A magnet a2 is provided on the fixed adapter 28 on the side of the flanged guide roller 27B so as to face the side surface of the fixed scale 24. This magnet 32 exerts an attractive force on the fixed scale 24 to attract the fixed adapter 28 to the fixed scale 24 side, and the flange-equipped guide roller 27B
The flange 27b is mounted at such a position that even when the flange 27b is in contact with the fixed scale 24, a small gap remains between it and the side surface of the fixed scale 24. Therefore, this magnet 3
2, the flange 27b of the guide roller 27B is brought into pressure contact with the side surface of the fixed scale 24. The magnet 32 may be an electromagnet or a permanent magnet. Note that one side of the fixed scale 24 is finished to be smooth because it comes into contact with the flange 27b of the guide roller 27B.

Next, the operation of the above device will be explained.

The document 13 placed on the document table glass 12 is held by the document presser 14.
The original 13 is irradiated with the light source 16, the reflected light is changed in the optical path by the reflective mirror 17, and is focused onto the reading element 19 by the condensing lens 18. The reading element 19 is electronically Main scanning is performed, and processing such as photoelectric conversion is performed. On the other hand, sub-scanning is performed by moving the slider 225 holding the optical unit 15 along the fixed scale 24 at a predetermined speed. During this traveling, the flange 27b of the flanged guide roller 27B held by the slider 25 is pressed against the side surface of the fixed scale 24 by the attraction force of the magnet 32, and is therefore guided by this side surface. Since the flange position is set at a predetermined position relative to the center of the optical unit 16, the optical unit 15 accurately travels at a constant position relative to the fixed scale 24 without wobbling laterally.

Additionally, as the slider travels, the guide roller 27B contacts the lower and side surfaces of the fixed scale 24 and rotates.
Since the flange 27b receives frictional resistance from the side surface of the fixed scale 24, the rotation of the guide roller 27B becomes heavier, the occurrence of cogging of the slider 25 is reduced, and the constant speed of the slider running is improved. Thus, optical unit 15
travels along the document 13 at a predetermined position at a constant speed, and good image reading is performed.

In the above embodiment, the optical unit 15 is configured to move relative to the stopped document table 11, but instead, the document table 11 is connected to a slider 25 of a linear pulse motor, and the document table 11 is moved. It's okay. Furthermore, it goes without saying that the optical unit is not limited to that of the illustrated embodiment, and may be constructed of a contact image sensor.

Effects of the Invention As is clear from the above explanation, the present invention uses a flanged kite roller as a guide roller of a linear pulse motor,
By configuring the flange of this guide roller to press against the side surface of the fixed scale and move, resistance is added to the rotation of the guide roller, reducing cogging of the slider running along the fixed scale and maintaining constant speed. This has the effect that the linear pulse motor can be applied to move the optical unit or document table in the reading device.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a reading device according to an embodiment of the present invention, FIG. 2 is a schematic front view thereof, and FIG. 3 is a schematic bottom view thereof.
FIG. 4 is a schematic perspective view of a general linear pulse motor, FIG. 5 is a side view for explaining its operation, and FIG. 6 is a schematic front view of a conventional linear pulse motor. 11...Original platen, 12...Original platen glass, 13...Original, 15...Optical unit, 21...Linear pulse motor , 24...
...Fixed scale, 25 ...Slider, 2
6...Guide roller shaft, 27A-...Guide roller, 27B...Guide roller, 27b
...Flange, 28...Fixed adapter, 30...Spacer, 32...Magnet. Name of agent: Patent attorney Toshio Nakao and 1 other person'M
Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] The document table includes a document table, an optical unit that optically reads the document on the document table, and a linear pulse motor that relatively moves the document table and the optical unit, and the linear pulse motor is provided in a stationary manner. a fixed scale, a slider movable along the fixed scale, and a guide that is rotatably held on both sides of the slider and that rolls into contact with one side of the fixed scale so as to maintain a constant distance between the slider and the fixed scale. The roller has a roller and an adapter that connects a driven body to the slider, and a guide roller located on one side of the slider is a flanged roller equipped with a flange that contacts a side surface of the fixed scale. A reading device characterized in that the adapter on the roller side is provided with a magnet facing a side surface of the fixed scale.