JPS5924051Y2 - Copy machine document feeder - Google Patents

Description

[Detailed Description of the Invention] The present invention has a conveyance means for conveying a document to a document illumination position, and first and second detection devices are disposed along the document conveyance path, and the first detection device A signal to start operation of the copying machine is generated by the AND of the first detection signal generated when the device detects the leading edge of the document and a print signal generated in advance, and the second detection device detects the leading edge of the document. The present invention relates to a document feeding device of a copying machine configured such that a paper feed signal for a copy sheet is overwritten by a second detection signal generated when the detection is performed.

It is well known that a document feeder of the type described above feeds the document into an illumination position in order to scan the document with illumination.

In this case, it is advantageous to attach a jam detection device to the document feeder that immediately detects when a document jams during its transportation.

However, the provision of a jam detection device inevitably complicates the entire device.

The present invention aims to provide a document feeder that can be equipped with a jam detection device while suppressing the above-mentioned drawbacks as much as possible. A distant relative of the above purpose.

Embodiments of the present invention will be described below with reference to the drawings.

In the drawing, a platen 2 is fixedly disposed on the top of a copying machine main body 1, and the platen 2 is made of a transparent material such as glass.

A document feeding device 3 according to the present invention is provided above the platen 2, and this device 3 has a plurality of endless belts 7 wrapped around a driving roller 4 and driven and guide rollers 5, 6.

This belt 7 is driven in the direction of arrow A.

A guide member 8 is provided around and close to the drive roller 4.
A discharge roller 9 for discharging the original is disposed to the right of the driven roller 5.

A continuous document transport path is thus formed, in which the first and second sensing devices 10, 11 are arranged at suitable locations near the entrance to this transport path, in this example around the drive roller 4.

In this case, the first detection signal from the first detection device 10 is input to the other input terminal of the logic circuit whose negative input is the output signal (print signal) of the print signal generator (not shown). , thereby generating a signal for starting operation of the copying machine, and on the other hand, the second detection device 11
The second detection signal from the second detection signal generates a copy paper feed signal, which will be described later.

At the same time, the first and second detection devices 10.11 work together to detect a document jam.

For the purpose of detecting this jam, in this example, a third detection device 12 is further provided near the exit of the document conveyance path.

As the first to third detection devices 10.11.12, the microswitch can be any suitable device known per se, such as a photoelectric detection device.

Next, the copying operation will be explained.

Before starting the copying operation, the light source 13 and mirror 14 of the exposure optical system disposed below the platen 2 are stopped near the left end of the platen as shown in the figure, and the power switch (not shown) of the copying machine is turned on. ) is turned on and a print button (not shown) in the print signal generating device is pressed to generate the print signal, whereby the belt 7 is driven by the drive roller 4 in the direction of arrow A.

An operator (not shown) moves the document 1 as shown by arrow B.
5 is inserted between the guide member 8 and the drive roller 4 from the entrance side of the document conveyance path, the document is first conveyed along the guide member 8 by the frictional force with the running belt 7.

In that case, the leading edge of the document 15 is at the detection position X of the first detection device.
, the detection device 10 detects this, and the first detection signal is logically ANDed with the print signal to generate a copying machine operation start signal.

As the light source 13 starts to light up, the photosensitive drum 16 installed inside the copying machine body starts rotating in the direction of the arrow, and the surface of the drum is charged by the charger 17, while the copies sent out from the paper feeder are charged. Paper 18 is the registration roller 19
Wait right in front of.

Next, the leading edge of the document 15 is at the detection position Y of the second detection device 11.
A second detection signal generated when passing through the paper feed signal causes a copy paper feed signal to be generated, thereby causing the registration roller 19 to
The rotation starts, and the waiting copy paper 18 begins to be fed toward the drum 16.

Subsequently, the original 15 is conveyed over the platen 2, and as it passes through an optically formed slit 2a, it is illuminated and scanned by a light source.

Thus, the light reflected from the original 15 passes through the mirror 14 and its optical system to expose the charged surface of the drum 6, thereby forming a latent image on the drum.

This latent image is converted into a toner image by the developing device 20, and when this toner image reaches the transfer section 21, the copy paper 18 fed toward the drum at the above timing is aligned with the toner image, and the toner image is The image is transferred to copy paper 18.

In this case, the position Y of the second detection device and the position of the optical slit (-2H) on the platen are set accurately in advance, and the document passes through the position Y of the second detection device 11 and then passes through the platen after a predetermined period of time. Since the slit position is reached, exposure and paper feeding are performed in synchronization, and the toner image and copy paper are accurately aligned.

However, depending on the relative relationship between the distance between the second detection device and the illumination position (optical slit), the distance between the exposure position and the transfer position of the photoreceptor drum, and the distance between the registration roller and the transfer position, the second
It may not be possible to output the registration roller rotation signal (copy paper feed signal) at the same time as the detection signal, but in this case,
A predetermined time interval may be provided between the second detection signal and the registration roller rotation signal.

Furthermore, in the case of variable-magnification copying, since the original moving speed or the photoreceptor rotation speed changes, it is preferable to change the predetermined time interval in accordance with the magnification.

The copy paper 18 that has been transferred passes through a device composed of a drum and then is discharged outside the machine, and the original document 15 that has been illuminated is discharged outside the machine by a paper discharge roller 9.

In the above operation, if the document 15 jams in the conveyance path, there is a risk that the document will be significantly damaged if left unattended, so it is necessary to immediately detect the jam and stop the conveyance of the document.

As mentioned earlier, in this example, the jam detection is performed by the first to third detection devices 10, 11, and 12.

Various known methods of jam detection using these devices can be considered.

For example, when the first detection device 10 detects the leading edge of the document, a timer (not shown) is triggered, and when the second detection device 11 does not detect the leading edge of the document even after a predetermined period of time has elapsed, a jamming signal is sent from the timer. By causing this to occur, it is possible to detect that the document has stopped (jammed) between the two detection devices 10 and 11.

A jam has also occurred when the second detection device 11 does not detect the rear edge of the document after a predetermined period of time has elapsed after the first detection device 10 has detected the rear edge of the document. It is also possible to generate a signal.

Furthermore, in order to be able to detect even if a document straddles the first detection device and the second detection device and stops (jams), a predetermined time elapses after the first detection device 10 detects the leading edge of the document. It is also advantageous for the jamming signal to be generated even when this first detection device 10 does not detect the trailing edge of the document.

There are other appropriate jam detection methods, but since they are already known, detailed explanations thereof will be omitted.

In exactly the same way, the second detection device 11 and the third detection device 12 can detect the occurrence of a document jam.

Incidentally, in a variable-magnification copying machine in which the copying magnification can be changed, the feeding speed of the document changes depending on the copying magnification, and in this case, the set time of the above-mentioned timer may be changed.

Furthermore, when a jamming signal is generated as described above, the document feeder can be automatically stopped or an indicator lamp can be turned on to make the operator aware of the occurrence of a jam.

In the above explanation, the document is illuminated while it is being conveyed, but the illustrated copying machine can also be constructed so that the document can be stopped on the platen and illuminated. A stopper device 22 for stopping the document is provided near the driven roller.

When the document reaches a predetermined position on the platen, the stopper device stops the document at the predetermined position, and the light source 13
The mirror 14 is moved from right to left in the direction indicated by arrow C, thereby illuminating the original.

When operated in this manner, the first and second detection devices can be used exclusively as jam detection devices.

As described above, according to the present invention, the conventional drawbacks can be eliminated with a simple configuration.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that it can be configured with various modifications.For example, the paper feeding timing can be performed using something other than the registration roller.

[Brief explanation of the drawing]

The drawings are explanatory diagrams showing one embodiment of the present invention. 7... Conveyance means, 10.11... Detection device, 15... Document.

Claims (1)

[Scope of utility model registration request] a conveying means for conveying the original to the original illumination position;
a first detection device that generates a detection signal; a second detection device that is disposed downstream of the first detection device and detects a conveyed document and generates a second detection signal; and a print signal generation device that generates a print signal. , a logic circuit that logically ANDs the print signal and the above-mentioned first detection signal and generates an operation start signal for the copying machine at that time; and a logic circuit that receives the above-mentioned second detection signal and generates a copy paper feed signal based on it. In the document feeding device of a copying machine having a paper feed signal generating device that generates a paper feed signal, the first
A document feeder comprising a jam detection device that can receive a detection signal and a second detection signal, determines occurrence of a jam based on whether or not the signals are received, or the timing of reception, and generates a jamming signal. Device.