JPH07172617A - Image reading device - Google Patents

Abstract

PURPOSE:To provide an image reading device capable of reducing cost and also reducing power consumption. CONSTITUTION:An image reading device which transports documents by the rotational motion of a transport roller 6 and reads images while pressing the surface of the sheet documents by the transport roller 6 is provided with a current value operating means to vary the current value applied to a motor 1 for driving the transport roller 6 and a pushing pressure operating means to vary the pushing pressure force for pressing the documents by the transport roller 6. Also it is provided with a means to automatically vary the current value applied to the motor 1 according to the pushing pressure force when the pushing pressure force for pressing the documents by the transport roller 6 is varied by a pushing pressure operation means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus such as a facsimile machine, a copying machine, an image scanner and the like, and more particularly to an image reading apparatus capable of conveying an original according to the quality of the original.

[0002]

2. Description of the Related Art Conventionally, as a document scanning system for a copying machine or a facsimile apparatus, a document fixing system in which a document is fixed and a reading scanning unit is moved, and a document transportation system in which a reading unit is fixed and a document is moved are used. Has been. Of these, the present invention is particularly effective in the document conveying system. Although this original feeding method is cheaper than the original fixing method, there is a problem that it is difficult to achieve this requirement regardless of the paper quality of the original because the original is read while reading the image while it is being fed. This is because the friction force between the conveyance roller (rubber roller, etc.) and the document surface is used as the conveyance force in the document conveyance method. However, the conveyance force fluctuates due to changes in the friction coefficient of the document surface or the document thickness, etc. This is because the conveyance may not be performed properly. For this reason, a large safety factor is set so that the document is conveyed regardless of the type of the document, and even if the document does not require a large conveyance force, the conveyance roller is pressed with an excessive pressing force. It is transported by pressing it.

[0003]

However, in the prior art as described above, high component strength is required even in an inexpensive model, the conveyance motor becomes large and expensive, and its applied current becomes large. Therefore, there is a drawback that the power consumption becomes large.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and eliminates the need to press the conveying roller against an original with an excessive pressing force, and the required component strength can be reduced. It is an object of the present invention to provide an image reading device which can be used and can reduce power consumption.

[0005]

In order to achieve the above object, the present invention provides an image reading apparatus for reading an image of an original document conveyed by the rotational movement of the conveying roller while pressing the surface of the sheet-like original document with the conveying roller. An image of the original document conveyed by the rotational movement of the conveyance roller while pressing the surface of the sheet-shaped original document with the conveyance roller, by providing current value operation means for changing the current value applied to the motor for driving the conveyance roller. In the image reading apparatus for reading the document, the conveying roller is provided with a pressing operation means for changing a pressing force for pressing the original, and when the pressing force for the conveying roller to press the original is changed by the pressing operation means, A means for automatically changing a current value applied to a motor for driving the conveying roller in accordance with a pressing force is provided. That.

[0006]

Since the current value operating means for changing the current value applied to the motor for driving the conveying roller is provided, the operator can change the current value applied to the motor according to the type of the document to be used. Further, since the pressing means for changing the pressing force of the conveying roller pressing the original is provided, the operator can change the pressing force of the conveying roller pressing the original according to the type of the original used. Furthermore, when the pressing force with which the conveying roller presses the original is changed by the pressing operation means, a means for automatically changing the current value applied to the motor in response to the pressing force is provided, so that the type of original can be changed according to the type of original. When the operator sets the pressing force, the corresponding optimum current value is automatically set.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 (a) and 1 (b) are a block diagram of a driver circuit which is a main part of an embodiment of an image reading apparatus according to the present invention and a configuration diagram of a carrying system. In FIG. 1A, reference numeral 1 is a stepping motor for driving the conveying roller (see (b)), and 2 is a stepping motor 1 by applying a reference voltage.
A motor drive circuit (motor driver) capable of changing the current value applied to the switch 3, a switch which is a current value operating means, and 4 an excitation phase switching signal generator. Also
In (b), 5 is a molding roller provided at a position facing the conveying roller 6, 7 is a timing belt for transmitting the driving force from the output shaft (pulley) 1a of the stepping motor 1 to the conveying roller 6, and S is a document. Is.

In the embodiment of FIG. 1, when the stepping motor 1 is rotated by the applied current output from the motor drive circuit 2 based on the signal from the excitation phase switching signal generator 4, the stepping motor 1 is driven via the timing belt 7. The carrying roller 6 rotates, and the mold roller 5 facing the carrier roller 6 rotates together therewith, and the sheet-shaped original S pressed by the mold roller 5 and the carrying roller 6 is conveyed. Although not shown, an image reading unit is provided on the conveyance path, and an image is read in parallel with the document conveyance.

In the embodiment shown in FIG. 1, the reference voltage is changed by turning the switch 3 on or off, whereby the current value applied to the stepping motor 1 is switched in two steps. For example, when the switch 3 is turned on, the current value is increased, and when it is turned off, the current value is decreased. The current value can be switched more finely by the voltage dividing circuit configuration of the reference voltage.
The switch 3 is provided, for example, in an operation unit of a facsimile machine or a copying machine to which the present image reading apparatus is applied, and determines the transport load based on the quality of the document, the change in the document thickness due to sticking of photographs, and the mass. When feeding a document that seems to be large, the operator turns on the switch 3. As a result, the driving force of the stepping motor 1 increases, and thus the conveying force of the conveying roller 6 increases.
On the other hand, in the normal usage mode, since many documents such as copy paper do not require a large carrying force, the switch 3 is turned off to reduce the current value. That is,
The transport drive system is designed to generate the torque required to properly transport a document such as copy paper when the smaller current value is selected.

FIG. 2 is a flow chart showing the operation of the embodiment shown in FIG. Further, FIG. 3 is a partial configuration diagram of the operation panel, in which the transport load due to the difference of the originals is measured for several typical original types (original forms), and the original types and the ON / OFF state of the switch 3 are checked. In this embodiment, the correspondence is displayed near the switch 3 on the operation panel 10. This improves the convenience of the operator.

FIG. 4 is a block diagram of the essential parts of the image reading apparatus according to the present invention. In the figure, reference numeral 9 is a pressure member (for example, a leaf spring) attached on the shaft 8 of the mold roller 5, and the mold roller 5 works so as to press the document S against the conveying roller 6. The mold roller 5 is movable in the vertical direction as described above, but is supported so as not to move in the horizontal direction in the drawing.

As shown in FIG. 4, the pressing member 9 composed of a leaf spring is configured to generate a pressing force in accordance with its bending rate. One end of is attached to the pressing operation means 11 on the operation panel 10. The pressing operation means 11 is configured to be movable in the direction parallel to the operation panel surface (the direction of the arrow in the drawing), and the bending rate of the pressing member 9 can be changed by this movement. If the pressing operation means 11 is moved to the left to increase the bending rate of the pressing member 9 as shown by the dotted line in the figure, the pressing force of the conveying roller 6 pressing the document S increases and the conveying force increases. Is clear from the figure. Since the force generated by friction is linearly proportional to the mass of the object, the pressing force may be increased n times to increase the carrying force n times.

FIG. 5 is a diagram showing an example in which the pressing operation means 11 of FIG. 4 is arranged on the operation panel, and the conveyance load due to the difference of the originals in relation to several typical original document types (original forms) is shown in advance. In this embodiment, the correspondence between the document type and the position of the pressing operation means 11 is measured and displayed on a knob movement area on the operation panel by a scale or the like. This improves the convenience of the operator. In FIG. 4, the pressing member 9 is shown as an example using a leaf spring, but another elastic member such as a coil spring may be used. The operation of the embodiment shown in FIG. 4 is shown in the flowchart of FIG. Also in this case, the pressing force is set large in the case of a document requiring a large conveying force, and is set small in the opposite case.

FIG. 7 is an explanatory view of the configuration of the operating portion of an embodiment in which the embodiment shown in FIG. 1 and the embodiment shown in FIG.
In the embodiment shown in FIG. 4, when the pressing force with which the conveying roller 6 presses the document is changed by the pressing operation means 11, the current value applied to the stepping motor 1 is automatically changed corresponding to the pressing force. You can As shown in FIG.
This can be realized by configuring the slide switch 11a having one and a plurality of contacts 112. That is, the contact 112 for increasing the current value applied to the stepping motor is sequentially arranged in the direction of increasing the pressing force, and the contact 112 for decreasing the current value is arranged in the direction of decreasing the pressing force. There is. Since the sliding member 111 is provided with the sliding contact 111a capable of contacting each contact 112, the contact 112 can be sequentially turned on and off as the slide member 111 moves. In this case, the switch 3 in the circuit shown in FIG. 1 is replaced with the slide switch 11a. See also FIG.
As shown in, the slide member 111 of the slide switch 11a
One end of the pressure member 9 is attached to the tip end of the pressure member 9, and the bending rate of the pressure member 9 changes as the slide member 111 moves in the direction of the arrow. The relationship between the pressing force and the current value applied to the stepping motor is that the current value increases as the pressing force increases. In other words, when the conveyance force is small, such as when using a normal copy paper as the original, the pressing force and the current value are both reduced, and when the photograph is pasted on the original surface or the original is long. When it is necessary to increase the carrying force, both the pressing force and the current value are increased.

In the above, it is possible to use a slide resistor instead of the slide switch. in this case,
It goes without saying that the changes in the pressing force and the current value are not stepwise but continuous. Similarly, also in the embodiment shown in FIG. 1, it is possible to use a slide resistor instead of the switch 3 to continuously change the current value. A DC motor or the like can be used instead of the stepping motor 1. In this case, a servo control circuit is generally used, and the excitation phase switching signal generator 4 shown in FIG. Be replaced by a bowl.

[0016]

As described above, according to the present invention,
Since the operator can change the current value applied to the motor according to the type of document used, in the case of a document that does not require a large carrying force, the power consumption can be reduced by setting the current value small. . Further, since the operator can change the pressing force with which the conveying roller presses the original according to the type of original to be used, in the case of an original that does not require a large conveying force, the pressing force can be set small. The cost of the device can be reduced by lowering the required component strength. Further, in the configuration provided with means for automatically changing the current value applied to the motor in response to the pressing force when the pressing force with which the conveying roller presses the document is changed by the pressing operation means, it is possible to change according to the type of the original. When the operator sets the pressing force by the operator, the corresponding optimum current value is automatically set, so that the operability is improved.

[Brief description of drawings]

1A and 1B are a block diagram and a configuration diagram showing an embodiment of a main part of an image reading apparatus according to the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment shown in FIG.

FIG. 3 is a diagram showing a display example of a main part of an operation panel of the embodiment shown in FIG.

FIG. 4 is a configuration diagram showing another embodiment of the main part of the image reading apparatus according to the present invention.

5 is a diagram showing a display example of a main part of an operation panel of the embodiment shown in FIG.

6 is a flowchart showing the operation of the embodiment shown in FIG.

FIG. 7 is a diagram showing a display example of a main part of an operation panel of another embodiment of the main part of the image reading apparatus according to the present invention.

FIG. 8 is a sectional view showing another embodiment of the main part of the image reading apparatus according to the present invention.

[Explanation of symbols]

1 ... Stepping motor, 2 ... Motor drive circuit, 3 ... Switch, 4 ... Excitation phase switching signal generator, 5 ... Mold roller, 6 ... Conveying roller, 7 ... Timing belt, 8 ...
Shaft, 9 ... Pressure member, 10 ... Operation panel, 11 ... Pressing operation means.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04N 1/00 108 1/04

Claims (3)

[Claims] 1. In an image reading apparatus for reading an image of an original document conveyed by the rotational movement of the conveyance roller while pressing the surface of the sheet-like original document with the conveyance roller, a current value applied to a motor for driving the conveyance roller is set. An image reading apparatus comprising a current value operating means for changing the current value. 2. An image reading apparatus for reading an image of an original document conveyed by the rotational movement of the conveyance roller while pressing the surface of the sheet-like original document with the conveyance roller, and changing the pressing force with which the conveyance roller presses the original document. An image reading apparatus comprising a pressing operation means. 3. When the pressing operation means changes the pressing force with which the conveying roller presses the document, the current value applied to the motor for driving the conveying roller is automatically changed corresponding to the pressing force. The image reading apparatus according to claim 2, further comprising a changing unit.