JPS58118674A - Driving device for plane reader - Google Patents

Abstract

PURPOSE:To faithfully transmit the driving characteristic of a motor to a reading mechanism and to use the reading mechanism for a long period under a good condition, by transmitting the driving force of the step-motor to the reading mechanism through a ball screw. CONSTITUTION:A reading mechanism 13 is installed in such a way that it freely makes movements in parallel with a platen 11 under the guidance of a guide rail 14, and the mechanism 13 is connected with a step-motor 21 through a ball screw 19 and a joint 20. The ball screw 19 consists of a nut-shaped member 22, a screw stock 24, and numerous balls 27. When the motor 21 is rotated, the screw stock 24 is rotated, the mechanism 13 is moved by the action of the ball screw 19, and then, information on an original is read. Therefore, the ball screw 19 does not expand, contact, and slip as in the case of conventional belts, and the driving characteristic of the motor 21 is faithfully transmitted to the reading mechanism 13 and the reading mechanism 13 can be used for a long period under a good condition.

Description

[Detailed description of the invention] The present invention relates to a drive device for a flat surface reading device.

In flat reading devices used in copying machines, etc., a document is placed on a fixed platen, and a reading mechanism arranged below or above the platen is moved parallel to the platen to read the image of the document. is being done. By the way, as shown in FIG. 1, the drive device of the reading mechanism in this type of conventional plane reading device applies the driving force of a step motor 1 to a timing pulley 3 via a timing belt 2.
The signal is transmitted to the timing belt 5 provided between the timing pulley 3 and the driven pulley 4, and the reading mechanism 6 is guided by the guide rail 7 and moved by the timing belt 5, thereby moving the platen. The image of the document 9 on the document 8 is read. However, in such a conventional drive device, since the timing belts 2 and 5 are used to transmit the driving force, the timing belts 2 and 5 expand and contract and vibrate when transmitting the driving force. Slip occurs in the transmission system. Therefore, it is difficult to faithfully transmit the drive characteristics of the step motor 1 to the reading mechanism 6, which leads to a disadvantage in that the quality of the read image deteriorates. In addition, when used for a long period of time, the timing belt 2.5 may undergo undesirable elongation due to fatigue, and therefore the driving force medium node must be readjusted or replaced with a new one.
There was a drawback that it had to be done.

The present invention has been made in view of the above circumstances, and by transmitting the driving force of the step motor to the reading mechanism via a ball screw, it is possible to faithfully transmit the driving characteristics of the step motor to the reading mechanism. It is an object of the present invention to provide a drive device for a flat surface reading device that can be used satisfactorily over a long period of time.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. Platen 11 made of transparent glass, etc.
A document 12 is placed on top of the document.

A reading mechanism 13 is disposed below the platen 11 so as to be movable in a direction parallel to the platen 11 while being guided by a guide rail 14 . The reading mechanism 13 is in its case 15
A plurality of light sources 16. Lens 17. The structure has a built-in reading element 18 and the like. This reading mechanism 13 is connected to a ball screw 19. It is connected to a step motor 21 via a joint 20. The ball screw 19 is
Nut-shaped member 2 provided in case 15 of reader 113
2, a threaded rod 24 arranged parallel to the guide rail 14 and rotatably supported at both ends by bearings 23, 23; It has a structure consisting of a large number of balls 27 interposed between a semicircular spiral groove 25 and a substantially semicircular cross-section spiral groove 26 provided on the outer peripheral surface of the threaded rod 24.

When the step motor 21 is driven, the threaded rod 24 rotates, thereby causing the ball screw 1 to rotate.
9, the reader 113 is guided by the guide rail 14 and moves along the platen 11 without rotating. And at this time of movement, light #! 16 illuminates the document 12 on the platen 11, the reflected light passes through the lens 17 and forms an image on the reading element 18, where it is converted into an electrical signal (image signal).

In this way, since the driving force of the step motor 21 is transmitted to the reading mechanism 13 via the ball screw 19,
When transmitting driving force, the ball screw 19 does not expand, contract, or slip unlike a conventional timing belt. Therefore, the drive characteristics of the step motor 21 can be faithfully transmitted to the reading mechanism 13.

As explained above, according to the drive device for a plane reading device according to the present invention, the driving force of the step motor is transmitted to the reading mechanism via the ball screw, so that the drive characteristics of the step motor can be faithfully applied to the reading device. This has the effect of improving the read image quality and making it possible to use it satisfactorily over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an example of a drive device for a conventional flat surface reading device, FIG. 2 is a schematic side view showing an embodiment of a drive device for a flat surface reading device according to the present invention, and FIG. It is an enlarged sectional view of the interior A of. 11...Platen 12...Original 13
...Reading mechanism 19...Ball screw 21...Step motor Application Patent attorney Umeo Yamauchi, Fuji Xerox Co., Ltd.

Claims (1)

[Claims] 1. In a flat reading device in which an image of a document placed on a platen is read by a reading mechanism that moves parallel to the platen, the driving force of a step motor, which is the driving source of the reading mechanism, is transmitted through a ball screw. A driving device for a flat surface reading device, characterized in that the drive device is configured to transmit power to the reading mechanism.