JPH02125565A - Picture scanner - Google Patents

Abstract

PURPOSE:To attain a large change in a picture size by delivering a torque of a drive means via a continuously variable speed change means to a scanning means and varying the scanning speed of the scanning means not only by a drive speed of the drive means but also by the continuously variable speed change means. CONSTITUTION:When the reduction rate is set by an operation panel 14 of a device main body 11, a motor control section 30 generates a pulse signal having a frequency in response to the reduction rate and a pulse motor 29 is driven by a pulse signal. In this case, the pulse motor 29 is driven by a high frequency not causing out of synchronism in a rated frequency band. When the pulse motor 29 is driven at a high speed, a tension of a V belt 28 is larger than the energizing force of a spring (not shown) regulating the groove width of the continuously variable speed change pulley 26. Thus, the groove width of the pulley 26 is widened and the diameter of the V belt 28 of the continuously variable speed change pulley 26 is decreased. Thus, the continuously variable speed change pulley 26 is driven at a high speed and a carriage 19 is moved at a high speed in response to the reduction rate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an image scanning device that is applied to, for example, an electronic copying machine or a scanner device, and exposes and scans a document image.

(Prior Art) In this type of image scanning device, an exposure scanning section is driven by a pulse motor, and the exposure scanning section is moved along a document table on which a document is set to read the document image. It has become.

Incidentally, in the image scanning device, it is possible to set the reading magnification of the original image, and the scanning speed of the original is changed according to the set magnification.

For example, when the magnification is reduced, scanning is performed at a higher speed than when the image is at the same magnification, and when the magnification is increased, the scanning is performed at a slower speed than when the image is at the same magnification.

The scanning speed of the exposure scanning section is controlled by changing the frequency of the signal that drives the pulse motor. but,
If you try to change the image size significantly, the wide range of frequencies used will include resonance areas, causing blurring in the read image signal, reducing resolution and distorting the image. ing. In addition, when the image size is small (high frequency side), distortion occurs, and the pulse motor may not be able to be controlled reliably.

Therefore, it is conceivable to narrow the range of frequencies used, but in this case, there is a problem that the size of the image cannot be changed significantly.

(Problem to be Solved by the Invention) This invention solves the problem that it is difficult to greatly change the size of an image by controlling a pulse motor as a driving means at a narrow frequency within the rated range. The object of this invention is to provide an image scanning device that can control the driving means within the rated values and can change the image size significantly.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a scanning means for exposing and scanning an original image, a driving means for driving the scanning means, and a driving means for driving the scanning means. a control means for changing the driving speed of the driving means according to a scanning range of a document image; and a continuously variable speed means interposed between the driving means and the scanning means and supplying power of the driving means to the scanning means. It was established.

(Operation) That is, the present invention transmits the power of the driving means to the scanning means via the continuously variable transmission means, and changes the scanning speed of the scanning means by the continuously variable transmission means as well as the driving speed of the driving means. , the driving means can be operated within the range of rated values, and moreover, large changes in image size are possible.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

4 and 5 show an image scanning device. This image scanning device optically reads a document image and supplies the read document image to, for example, a printing device or a storage device (not shown).

A document table 12 on which a document is set is provided in the second part of the main body 11 of the apparatus, and the document table 2 is covered with a document table cover 13 that can be opened and closed. Further, an operation panel 14 is provided at the top of the device main body 11. This operation panel 14 is provided with a reading key for instructing the start of reading, a magnification setting key for setting the reading magnification, and the like.

On the other hand, an exposure scanning section 15 for reading the original set on the original table 12 is provided on the back side of the original table 12. The exposure scanning section 15 includes an exposure lamp 16 that irradiates light onto the document, a light converging lens 17 that converges light reflected from the document, and a light converging lens 17 that converts the light guided by the light converging lens 17 into electricity, e.g. A photoelectric converter 18 consisting of a CCD line sensor is provided.

FIG. 1 shows the main parts of the exposure scanning section 15. As shown in FIG.

The carriage 19 holds the exposure lamp 16, the light converging lens 17, and the photoelectric converter 18. A roller 20 is provided at one end of the carriage 19, and the roller 20 runs on a guide rail 21. Further, a guide shaft 22 is passed through the other end of the carriage 19, and the carriage 19 is connected to the kite shaft 22.
2, it is said to be able to slide freely. Pulleys 23 and 24 are disposed near both ends of the guide shaft 22, and a timing belt 25 is wound around these pulleys 23 and 24. The carriage 19 is connected to the timing belt 25.

Further, the pulley 24 is attached to a continuously variable speed pulley 26 that constitutes a well-known V-belt continuously variable transmission. This continuously variable speed pulley 26 is of a type that controls the power transmission ratio by changing the position of the V-belt with respect to the boot according to, for example, the biasing force of a spring that regulates the groove width of the pulley and the tension of the V-belt. It is something. A V-belt 28 is stretched between the continuously variable speed pulley 26 and the pulley 27, and the pulley 27 is driven by a pulse motor 29.

A motor control section 30 is connected to this pulse motor 29 . This motor control section 30 includes the operation panel 14
A pulse signal of a predetermined frequency is generated according to the magnification set by the magnification setting key, and the pulse motor 29 is driven by this pulse signal.

In addition, a tension roller 31 is provided to keep the tension of the front V belt 28 constant.

In the above configuration, the operation will be explained.

For example, when a reduction magnification is set using the operation panel 14 of the device main body 11, a pulse signal having a frequency corresponding to the reduction magnification is generated in the motor control unit 30, and the pulse motor 29 is driven by this pulse signal. .

In this case, the pulse motor 29 is driven at a high frequency within the rated frequency band that does not cause tax adjustment. When the pulse motor 29 rotates at high speed, the tension of the V-belt 28 becomes larger than the biasing force of a spring (not shown) regulating the groove width of the continuously variable pulley 26. Therefore, Fig. 2 (
As shown in a) and (b), the groove width of the continuously variable temperature pulley 26 becomes wider, and the diameter of the V belt 28 in the continuously variable speed pulley 26 becomes smaller. Therefore, the continuously variable speed pulley 26 is rotated at high speed, and the carriage 19 can be moved at high speed according to the reduction magnification.

On the other hand, when the magnification factor is set using the operation panel 14, the motor control section 30 generates a pulse signal with a frequency corresponding to the magnification factor, and the pulse motor 29
It is driven by this pulse signal. In this case, the pulse motor 29 is driven at a lower frequency within the rated frequency band.

When the pulse motor 29 is rotated at a low speed, the tension of the V-belt 28 becomes smaller than the biasing force of a spring (not shown) regulating the groove width of the continuously variable pulley 26.

Therefore, as shown in FIGS. 3(a) and 3(b), the groove width of the continuously variable speed pulley 26 becomes narrower, and the diameter of the V-belt 28 in the continuously variable speed pulley 26 becomes larger.

Therefore, the continuously variable speed pulley 26 is rotated at a low speed, and the carriage 19 can be moved at a low speed according to the enlargement magnification.

According to the above embodiment, the carriage 19 is driven by the pulse motor 29 via the continuously variable speed converter 926.

Therefore, the pulse motor 29 can be driven in a narrow frequency band, and the scaling factor can be set to a large value.

In addition, since the pulse motor 29 is driven within a narrow frequency band, it is possible to suppress distortion and resonance of the pulse motor 29, and there is no adverse effect on image reading.

In the above embodiment, a continuously variable transmission using a V-belt is used as the continuously variable transmission, but the present invention is not limited to this.

Further, in the above embodiment, an image scanning device that converts a read original image into an electrical signal and supplies it to a printing device has been described, but the invention is not limited to this, and the copying magnification can be set. It is also possible to apply the present invention to ordinary electronic copying machines that are capable of.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, the power of the driving means is transmitted to the scanning means via the continuously variable transmission means, and the scanning speed of the scanning means is adjusted not only to the driving speed of the driving means. By changing the drive means using the continuously variable transmission means, it is possible to provide an image scanning device that can operate the drive means within the rated value range and can also make large changes in image size possible.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the present invention, and FIGS. 2 and 3 are diagrams shown to explain the operation of FIG. 1, and FIG. 4 is a perspective view showing the main parts. 5 is a perspective view showing the image scanning device, and FIG. 5 is a configuration diagram showing the main parts of the image scanning device. 11... Image scanning device, 15... Exposure scanning unit, 19
... Carriage, 26... Continuously variable speed pulley, 29.
...Pulse motor. Applicant's Representative Patent Attorney Takehiko Suzue Flow Figure 2 Figure 5

Claims (1)

[Scope of Claims] A scanning means for exposing and scanning an original image; a driving means for driving the scanning means; and a control means for changing a driving speed of the driving means according to a scanning range of the original image by the scanning means. , a continuously variable transmission means interposed between the driving means and the scanning means, and supplying motive power of the driving means to the scanning means.