JPH03191663A - Image reading device - Google Patents

Abstract

PURPOSE:To prevent a driving part of a platen roller from receiving the undesired load by separating an image sensor from the platen roller when no original passes through a press contact part between the platen roller and the image sensor. CONSTITUTION:An original is transferred and the tip of the original reaches a switch 10 to turn it on. Thus a solenoid 7 is turned off and an image sensor 2 is pressed to a platen roller 1 since the tip of the original is set close to a reading surface 2a of the sensor 2. The original is pressed to the sensor 2 and the roller 1 at a press contact part 9 and an image is read by the self- scanning function of the sensor 2 during the transfer of the original. When the read of the original is nearly through, the rear end of the original passes the switch 10 and turns off the signal of the switch 10. At the same time, a timer (not shown in the diagram) contained in a CPU 13 starts to count a prescribed time. Thus the sensor 2 is separated from the roller 1 when no original passes through the part 9 between the roller 1 and the sensor 2 in a working state of the roller 1. As a result, the undesired load is omitted for the driving part of the roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in image reading devices used in copying machines, facsimile machines, and the like.

(Prior Art) Copying machines, facsimile machines, and the like have been widely used in the past in which a contact type image sensor is used in the reading section. In such a structure, the image sensor is pressed against the image sensor and a platen roller disposed opposite to the image sensor using a biasing means such as a spring. The original is supplied to a pressure contact portion between the image sensor and the platen roller, and the original is conveyed between the image sensor and the image sensor by driving the platen roller, and the image on the original is read.

(Problem to be Solved by the Invention) In the image reading device configured as described above, the drive of the supply means for supplying the document toward the pressure contact section is started, and the platen roller connected to the supply means is also driven. Some devices are configured to start driving at the same time. In this case, the document has not yet reached the pressure contact area between the platen roller and the image sensor, so the platen roller and image sensor This increases the frictional force between the rollers and places a large load on the platen roller drive unit, which is undesirable.

Therefore, an object of the present invention is to provide an image reading device that solves the above-mentioned conventional problems.

(Means for Solving the Problems) An image reading device of the present invention includes a platen roller that conveys a document, a contact type image sensor that is pressed against the platen roller, and a document that moves the document toward the pressure contact portion between the platen roller and the image sensor. In an image reading apparatus, the image reading apparatus has a discriminating means for discriminating whether or not a document is passing through the pressure contact part while the platen roller is being driven, and an image sensor is connected to the platen when the discriminating means does not determine whether the document has passed through the pressure contact part. The present invention is characterized by comprising a separating means for separating the roller from the roller.

(Function) The image reading device configured as described above is capable of separating the image sensor from the platen roller when the platen roller is being driven and the document is not passing through the pressure contact portion between the platen roller and the image sensor. Therefore, there is no obstacle to the rotational drive of the platen roller, and therefore no extra load is applied to the drive section of the platen roller.

(Example) Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a schematic configuration diagram of an image reading device. 1st
In the figure, 1 is a platen roller, and 2 is a contact type image sensor. The platen roller l and the image sensor 2 are arranged one above the other with the document conveyance path 3 in between. The image sensor 2 is arranged within the guide 4 and is attached to the bottom surface 4 of the guide 4.
A spring 5 is disposed between a and the image sensor 2 to press the image sensor 2 toward the platen roller 1. Further, a notch 6 is provided on the bottom surface 4a,
A plunger 8 of a solenoid 7 is inserted into the guide 4 through this notch 6, and is connected to the bottom surface of the image sensor 2. When the solenoid 7 is in a non-energized state, the image sensor 2 is pressed against the platen roller 1 by the action of the spring 5 (the state shown by the solid line in FIG. 1). When the solenoid 7 is energized, it pulls the image sensor 2 downward via the plunger 8, and its reading surface 2a is lowered to the position shown by the broken line in FIG. 1, and the pressure contact between the platen roller l and the image sensor 2 is released. .

A timing switch 10 is provided on the upstream side in the conveying direction of the pressure contact portion 9 where the platen roller l and the image sensor 2 are in pressure contact with each other in the conveyance direction. Controls ON-OFF.

Further, on the upstream side of the switch 10, a supply roller 11 and a pressure contact blade (separation piece) 12 that are in pressure contact with the supply roller 11 are arranged. 9.

Although not shown, the platen roller 1 and the supply roller 11 are connected and driven by a common drive motor.

Next, a part of the control section of the apparatus of this embodiment will be explained with reference to FIG. ″ This control unit includes a CPU 13 as a central processing unit, and
The PU13 has a ROM1 in which predetermined operating procedures, etc. are written.
4 and RAM 15 for storing data at -.
are connected. Also, the above switch lO is 0N-O
The FF signal and the signal from the operating section 16 are input to the CPU 13. The CPU 13 drives a motor 17 mechanically connected to the platen roller 1 and the supply roller 11 via a motor driver 18 based on signals from the switch 10, the operating section 16, etc.
to drive and control. Furthermore, the CPU 13 uses the image sensor 2
It also controls ON-OFF of the solenoid 7 for pressing the platen roller 1 into contact with and separating it from the platen roller 1.

The operation of this embodiment will be explained with reference to FIG.

In this embodiment, when the machine is in the initial state, that is, when the machine is in a standby state, the solenoid 7 is OFF, so the image sensor 2 is in pressure contact with the platen roller 1. A document is set between the supply roller 11 and pressure contact blade 12 of the image reading device that is waiting in this state, and the operation switch (switch for starting image reading) is turned on.
When this happens (step S1), the solenoid 7 is first turned on and the image sensor 2 is separated from the platen roller 1 (step 32). The motor 17 is driven, and the platen roller 1 is mechanically connected to the motor 17.
, the supply roller 11, etc. start driving (step 33
). At this time, since the image sensor 2 is separated from the platen roller 1, the motor 17 that drives the platen roller 1 is not subjected to any extra load. Then, when the document is transported and the leading edge reaches the switch 10 and turns it ON (step S4), the solenoid 7 is turned OFF because the leading edge of the document is close to the reading surface 2a of the image sensor 2.
The image sensor 2 is brought into pressure contact with the platen roller l (step S5). The image of the document is read by the self-scanning function of the image sensor 2 while being conveyed while being pressed against the image sensor 2 and the platen roller l in the pressure contact section 9 (step S6). When the reading of the original is nearing the end, the trailing edge of the original passes through the switch 10.
The signal of switch 10 is turned OFF (step S7),
At the same time as the switch 10 is turned off, a timer (not shown) inside the CPU 13 starts counting a preset time (
Step 38).

In step S9, it is determined whether or not the timer ■ has counted the set time. The time from when it is determined that the switch is turned off until the trailing edge of the document passes through the pressure contact portion 9 is determined and set from the relationship with the conveyance speed. If the timer (2) is up, the solenoid 7 is turned on to separate the image sensor 2 from the platen roller (step 510). As a result, a document is always present between the image sensor 2 and the platen roller 1 when the two are in pressure contact, and when there is no document between the two, the image sensor 2 is quickly moved to the platen roller. It can be separated from 1.

In step 311, it is determined whether the next document has been conveyed. Switch 1 depending on the leading edge of the next document.
If 0 is turned on, the process returns to step S5, and the same process as that for the first original is performed.

If the switch 10 is not turned on, it is determined whether the timer 1 has counted the set time (step 512). The time that should be set in advance for this timer ■ is the calculated time from when the trailing edge of the previous document turns off switch 1o until when the leading edge of the next document turns on switch 1o, with some leeway. . If the timer 2 is not up in step S12, the process returns to step 311, and it is checked again whether the switch 10 is turned on.

That is, in step Sll and step 512, the presence or absence of the next document is checked. And if it is the final manuscript (step S1
2) confirms whether the final document has been ejected (step 513), and if it has been ejected, each roller is stopped and the solenoid 7 is turned off to return to the standby state (step S14.15).

In the above embodiment, the image sensor 2 and the platen roller 1 are kept in pressure contact when the apparatus is on standby. You can also leave it there. In this case, if the mechanical configuration is changed so that when the solenoid 7 is de-energized, the platen roller 1 and the image sensor 2 are in a separated state, and when the solenoid 7 is energized, the platen roller 1 and the image sensor 2 are in pressure contact.
The solenoid 7 may be turned ON only while the document is present in the pressure contact portion 9. By keeping the image sensor 2 and the platen roller 1 apart from each other when the apparatus is on standby, local deformation of the platen roller 1 can be prevented.

(Effects) As explained above, according to the image reading device of the present invention, when the platen roller is being driven and the document is not passing through the pressure contact portion between the platen roller and the image sensor, the image sensor is separated from the platen roller. Since the platen roller does not come into contact with the image sensor, the drive section of the platen roller does not receive any extra load. Further, it is possible to prevent the platen roller from coming into contact with the image sensor and being worn out.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an image reading device showing an embodiment of the present invention, FIG. 2 is a control section of the image reading device shown in FIG. 1, and FIG. 3 is an operational procedure of the image reading device shown in FIG. This is a simple flowchart. l...Platen roller 2...Image sensor 7...Solenoid 9...Press contact part 10... -Switch II... -Supply roller

Claims (1)

[Claims] In an image reading device that includes a platen roller that conveys a document, a contact type image sensor that is pressed against the platen roller, and a supply means that supplies the document toward the pressure contact portion between the platen roller and the image sensor, the platen roller is being driven. The image reading apparatus is characterized by comprising: a determining means for determining whether or not the document is passing through the press-contact part; and a separating means for separating the image sensor from the platen roller when the determining means does not determine whether the document has passed. Device.