JPH03132769A - Automatic document feeder - Google Patents

Abstract

PURPOSE:To accurately stop a fed document at a reference exposure position at all times by measuring the number of pulses generated in synchronism with the rotation of a conveying roller or its rotation time from when a 1st sensor detects the tail end of the document during its conveyance to when a 2nd sensor detects it, and determining the stop period of the document according to the measurement result. CONSTITUTION:When a heat end size sensor 6 detects the head end of the document, the conveying motor 22 is turned on to drive a conveyor belt 12 and also drive a pull-out roller couple 9 through a registration clutch, so that the document passes from the pull-out roller couple 9 to the conveyor belt 12. At this time, a counter calculates the pulses generated in synchronism with the conveying motor 22 from when the 1st registration sensor 7 detects the tail end of the passing document to when the 2nd registration sensor 8 detects it. Then the counted value is sent to a motor stop control means D as data for stopping the document at the specific reference exposure position M on contact glass 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic document feeding device that is mounted on the upper part of a copying machine body and automatically feeds documents.

[Conventional technology]

In general, an automatic document feeder mounted on the top of a copying machine automatically feeds the originals on the document table one sheet at a time by a paper feeder, and contacts the copying machine using a conveyor belt driven by a conveyor motor. The sheet is conveyed to a predetermined reference exposure position on the glass and stopped, and after the exposure is completed, the sheet is again conveyed to the sheet discharge section by the conveyor belt and discharged.

Such an automatic document feeder is equipped with one registration sensor on the conveyance path in the paper feed unit to detect the document being conveyed, and the registration sensor detects the leading or trailing edge of the fed paper. 1. For example, start measuring the number of pulses generated from a rotary encoder directly connected to the transport motor, and stop the transport motor when the measured value matches the sum of a predetermined value instructed in advance and a correction value described later. , the document being conveyed is stopped at a reference exposure position on the contact glass.

Note that when this automatic document feeder is installed on a copying machine, the correction value refers to a predetermined volume that is installed on the control board inside the device, for example, when a service engineer performs a trial run after completing the installation work. The original being conveyed on the contact glass is adjusted to stop at the standard exposure position by turning the contact glass, and this refers to the number of pulses corresponding to the adjustment.

[Problem to be solved by the invention]

However, in conventional automatic document feeders like this, the document is conveyed while being in contact with the contact glass, which inevitably causes friction between them. Since the conveyance amount (speed) of the document per unit time changes when the document is conveyed over the top, the document set on the contact glass will shift from the standard exposure position when the conveyance motor stops, resulting in portions that are not copied onto the paper. This has caused problems such as sometimes occurring.

Further, as the friction coefficient of the conveyor belt and the contact glass changes over time, the conveyance speed of the document conveyed on the contact glass changes with the passage of time, causing the same problem as described above.

Therefore, when such document misalignment occurs, you can adjust the volume as described above and correct the transport time so that the document stops at the standard exposure stop position. It is extremely troublesome to repeatedly perform correction operations, and this has the disadvantage of interfering with copying operations.

This invention has been made in view of the above-mentioned points, and the document is always placed at the standard exposure position on the contact glass of the copying machine, regardless of the type of document being used or changes over time in each part of the device. The purpose is to make it stop accurately.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an automatic document feeder as described above.

As shown by the functional blocks in FIG. 1, a first sensor A and a second sensor B are arranged along the document conveyance path at predetermined intervals in the document conveyance direction to sequentially detect the trailing edge of the document. pulses generated in synchronization with the rotation of the transport motor during the period from when the first sensor A detects the trailing edge of the original to when the second sensor B detects the trailing edge of the original while the original is being transported by the transport belt. A measuring means C that measures the number or rotation time, and a motor stop that controls the transport motor to stop by determining the stop timing to stop the document being transported at the reference exposure position according to the measurement result by the measuring means C. A control means is provided.

[For production]

According to the automatic document feeder configured as shown in FIG.
With most of the document being conveyed by the conveyor belt over the contact glass, it is necessary for the trailing edge to be conveyed a predetermined distance from passing the first sensor A to passing the second sensor B. The number of pulses (the number of pulses generated in synchronization with the rotation of the transport motor) or the rotation time of the transport motor is measured, and the document being transported is stopped at the standard exposure position on the contact glass of the copying machine according to the measurement results. Since the timing to stop the transfer motor is determined and the conveyance motor is stopped, the document can always be accurately set at the reference exposure position without being affected by the type of document being used or changes over time in each part of the device.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to FIG. 2 and subsequent figures.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

FIG. 2 is a schematic diagram of an automatic document feeder showing an embodiment of the present invention.

This automatic document feeder (hereinafter abbreviated as rADFJ) 1
The feeding section includes the document table 2, the calling roller 39, the separation roller pair 4, and the set sensor 5. A paper feed section consisting of each detection section of a leading edge/size sensor 6, a first registration sensor 7, and a second registration sensor 8, and a pull-out roller pair 9. A conveying section consisting of a conveying belt 12 stretched between a driving roller 10 and a driven roller 11, a pair of paper ejection rollers 13, a paper ejection sensor 14, and a document receiver 16 provided on a paper ejection section cover 15.
It is equipped with a paper ejection section consisting of etc.

Note that the tip/size sensor 6 and the first registration sensor 7
, and the second registration sensor 8 are sequentially arranged at predetermined intervals in the document conveyance direction along the document conveyance path, as shown in FIG.

Furthermore, although not shown in FIG. 2, there is a paper feed motor 21 shown in FIG. Conveyance motor 22゜Discharge motor 2
3 motors, call solenoid, resist solenoid, and claw release solenoid.

Solenoids and clutches such as separation release solenoid 24
has been established.

Here, the operation of each of the above sections will be explained.

On the document table 2 of the ADF 1 shown in FIG. 2, documents P to be copied are stacked with the image side facing down.

When this is detected by the set sensor 5 and a copy start button (not shown) on the main body of the copying machine is pressed, the calling roller 3 descends and comes into close contact with the uppermost document P.
A claw stopper (not shown) for prohibiting document feeding is released to prepare for paper feeding.

Then, after a short delay, the paper feed motor 21 shown in FIG. 3 is turned on, and the pick-up roller 3 and separation roller pair 4 are driven and begin to rotate in the direction of the arrow in FIG. Further, in order to improve the conveyance of the original and to prevent double feeding, the original is frictionally separated by a pair of separation rollers 4, and only one sheet is fed, and passes through the leading edge/size sensor 6.

When the leading edge of the fed document is detected by the leading edge/size sensor 6, the pick-up roller 3 rises and returns to the standby position, and after a period of time until the leading edge of the document reaches the pull-out roller pair 9, the feed motor is activated. 21 is turned off, and the rotation of the calling roller 32 and separation roller pair 4 is stopped.

Further, only while the leading edge/size sensor 6 is on, the gap between the pair of separation rollers 4 is released to prevent the document from becoming dirty.

On the other hand, when the leading edge/size sensor 6 detects the leading edge of the document, the transport motor 22 shown in FIG. 9 is driven, and the document is transferred from the pull-out roller pair 9 to the conveyor belt 12.
The uke is handed over.

At this time, the trailing edge of the passing document is located at the first registration sensor 7.
The pulses generated in synchronization with the transport motor 22 are measured by a counter during the period from when the pulses are detected by the second registration sensor 8 to when they are detected by the second registration sensor 8, and the count value is set at a predetermined reference exposure position on the contact glass 17. This is data for stopping the manuscript, and the details will be explained later.

Also, from the time the leading edge of the document is detected by the first registration sensor 7 or the second registration sensor 8 until the trailing edge passes, the pulses generated in synchronization with the conveyance motor 22 are processed separately from the above-mentioned counter. This counter is used to measure the size of the document, and the count value is sent to the copying machine as document size data.

However, with only the length in the conveyance direction determined by the registration sensor 7 or 8 as described above, for example, the length in the conveyance direction when A4 is fed horizontally and when A5 is fed vertically is not the same. Therefore, it is impossible to limit the size of the document, so the width is also detected by the leading edge/size sensor 6 and sent as size data to the copying machine main body.

Further, after the trailing edge of the document passes the registration sensor 7, the registration clutch is turned off and the pull-out roller pair 9
will also stop.

The conveyance belt 12 receives the original from the pull-out roller pair 9, and conveys the original over the contact glass 17 of the copying machine body. When the leading edge of the original reaches the reference position M, the conveyance motor 22 is turned off and stopped. do.

After the exposure is completed, the transport motor 22 and the paper ejection motor 23 shown in FIG. The original is transferred from the conveyor belt 12 to the paper ejection sensor 1
4 and is provided on the paper ejection section cover 15.
excreted during the day.

On the other hand, the feeding of the next original starts due to the paper discharge command signal from the copying machine main body and the detection of the original by the set sensor 5.
Thereafter, operations similar to those described above are repeated until there is no document P on the document table 2 anymore.

FIG. 3 is a block diagram showing the configuration of the control system of ADF1.

The control unit 20 of this ADFl transmits detection signals from each sensor/switch 25 including the above-mentioned sensors 5 to 8 to I/○.
In addition to inputting via the interface 26, signals are sent and received to and from the control unit inside the copying machine main body, and each motor 21 to
23. A microcomputer (hereinafter referred to as rCPUJ) 27 that controls each solenoid/clutch 24, and a paper feed motor driver 28 for the paper feed motor 21. Transport motor 2
DC servo circuit for 2 29. Paper ejection motor driver 30 for the paper ejection motor 23. It is composed of a solenoid/clutch driver 31 for each solenoid/clutch 24 and a reset circuit 32.

As each sensor, a photosensor consisting of a light emitting diode (LED) and a phototransistor (PT) that receives the transmitted light or reflected light is used, but instead of this,
Other sensors such as microswitches may also be used.

The set sensor 5 shown in FIG. 2 as each sensor/switch 25 is for determining whether or not there is a document on the document table 2. If there is, it is detected and the
10 interface sends a signal on the 2nd.

The leading edge/size sensor 6 consists of two sensors, a leading edge sensor and a size sensor, of which the leading edge sensor determines whether or not a document has been fed. send a signal to.

In addition, the size sensor is disposed at a position in the width direction where it can distinguish between originals that have the same length in the feeding direction but different widths (for example, A4 landscape orientation and AS portrait orientation). This is used to determine a document whose size cannot be determined solely based on the measurement result of the number of pulses generated from a rotary encoder 33 (described later) during detection, and the detection signal is sent to the I10 interface 26.

The first registration sensor 7 and the second registration sensor 8 also serve as the first sensor A and the second sensor B shown in FIG. Each sensor 7.8 detects the document while it is being conveyed, and sends a detection signal to the I10 interface 26.

The ejection sensor 14 is for determining whether the original has been ejected or not, and when the trailing edge of the original passes, it sends a detection signal to the work/○ interface 2nd.

The I10 interface 26 is involved in controlling input signals, inputs signals sent from the above-mentioned sensors, and sends them to the cptr 27 as necessary.

The reset circuit 32 is a circuit for returning each function of the ADFI to its initial state, and is activated when the power is turned on, a command from an operation panel (not shown) on the copying machine body, or a command from the CPU 27, for example, when a document is fed. Even in the middle of the process, the operation can be reset and returned to the initial state.

The paper feed motor driver 28 is activated by an on signal from the set sensor 5, a copy start command from the copying machine body, etc.
The paper feed motor 21 is driven by a command from the PU 27.

The DC servo circuit 29 is a circuit for driving the transport motor 22, which is a servo motor, at a constant speed.The DC servo circuit 29 is a circuit for driving the transport motor 22, which is a servo motor, at a constant speed. A pulse corresponding to the amount of rotation generated by the rotary encoder 33 is input as a feedback signal to control the rotation speed of the transport motor 22 to match the command value.

The paper ejection motor driver 30 drives the paper ejection motor 23 in response to a command from the CPU 27 based on a paper ejection command signal from the copying machine main body after exposure.

The CPU 27 is a general-purpose 16-bit or 32-bit microcomputer that centrally controls the ADFi.
The motors 21 to 23 and the solenoids are controlled by the detection signals from each sensor input through the I10 interface, the pulse signal from the rotary encoder 33, and the data or commands sent from the copier main body through the serial interface. - Controls the loads such as the clutches 24 so that they are driven at the required timing.

Therefore, this CPU 27 also functions as the measuring means C and motor stop control means shown in FIG.

Next, the operation of this embodiment will be specifically explained with reference to FIG. 4 and subsequent figures.

First, in order to simplify the explanation, as shown in FIG. The distance between the contact glass 170 reference positions M is 470 [nm].

As a result, while the document is being conveyed by the conveyor belt 12, the first registration sensor 7 detects the trailing edge of the document until the second registration sensor 8 detects the trailing edge of the document. Number of pulses (rotary encoder 3 in Figure 3)
3) and the number of pulses from when the second registration sensor 8 detects the leading edge of the document until it reaches the reference position M have the following relationship.

However, the former number of pulses will be referred to as the reference pulse number, and the latter number will be referred to as the document stop pulse number.

0=Reference pulse number×47 FIG. 5 is a flowchart showing pulse counting processing by the CPU 27 of the control section 20.

This routine starts when called from the main routine (not shown), and first the rotary encoder 3 shown in FIG.
Determine whether the pulse input generated from 3 is 1° (high level), and if it is not 1°, set the pulse edge flag to 1°.
Set to ° and return to the main routine.

Also, if the pulse input is 1°, the pulse edge flag will be 1.
If the pulse edge flag is 1°, the pulse edge flag is reset to 0°, and the pulse counter and reference counter in the CPU 27 are each incremented (+1). t, return to the main routine.

That is, its pulse counter and reference counter.

It is incremented every time the pulse rises (°0°→°1°).

FIG. 6 is a flowchart showing the processing of a document conveyance job, and FIGS.
The processing details are shown below.

Moreover, FIGS. 12(a) to 12(d) are timing charts for explaining the operation timing of each part related to the present invention.

In FIG. 6, the CPU 27 receives a document feed command from the copying machine main body, starts the paper feed motor 21 shown in FIG. If it is immediately after the document transport job is started, the transport job counter in the CPU 27 is incremented (set to 1), and then the value of the transport job counter is checked.

At first, the transport JOB counter becomes "1", so the JOBI process shown in FIG. 7 is performed.

This JOBI process is as shown in FIG.

When the second registration sensor 8 detects the leading edge of the document, that is, when the output of the second registration sensor 8 rises as shown in FIG.
After resetting to OJ and incrementing the transport JOB counter to make the count value 2, the process returns to the main routine.

If the conveyance JOB counter is "2" in the routine shown in FIG. 6, then the process moves to JOB2 shown in FIG.

Here, when the trailing edge of the document is detected by the first registration sensor 7, that is, when the output of the first registration sensor 7 falls as shown in FIG. 12(A), the reference counter is set to "0". After resetting and incrementing the transport JOB counter to make the count value "3", the process returns to the main routine.

If the conveyance job counter is "3" in the routine shown in FIG. 6, the routine then shifts to the process of JOB3 shown in FIG.

Here, when the second registration sensor 8 detects the trailing edge of the document, that is, as shown in FIG.
When the output of the registration sensor 8 falls, the CPU 2
The document stop pulse that is the result of calculating the product of the reference pulse number X, which is the value of the reference counter shown in FIG. In addition to storing the data of the number (zX47), the transport JOB counter is incremented to
4", then return to the main routine.

If the transport JOB counter is "4" in the routine shown in Figure 6, the process then proceeds to JOB4 shown in Figure 10, and the value of the pulse counter reaches the number of original stop pulses (zX47), which is the value of the original stop pulse number register. When it reaches the point, the transport motor 22 is turned off, the transport JOB counter is reset to "O", and the process returns to the main routine.

When the transport JOB counter reaches "0" in the routine shown in FIG. 6, the process then shifts to the JOBO shown in FIG. 11, completes all document transport job processing, and returns to the main routine.

As described above, according to this embodiment, during the period from when the first registration sensor 7 detects the trailing edge of the document while the document is being conveyed by the conveyor belt 12 to when the second sensor B detects the trailing edge of the document, the conveyance motor is Rotary encoder 33 directly connected to 22
According to the measurement result, that is, the number of pulses required to actually transport the original on the contact glass at a predetermined ratio M (in this example, 10 am), the original being transported is transferred to the copying machine main body. Since the stop timing for stopping at the reference exposure position on the contact glass 17 is determined and the conveyance motor 22 is stopped, automatic feeding is possible even when multiple different types of paper are used or when various parts of the apparatus change over time. The paper original is accurately set at the reference exposure position.

In this embodiment, the number of pulses from the rotary encoder 33 directly connected to the transport motor 22 is measured, but if a stepping motor is used as the transport motor, the number of pulses to control the rotation angle Alternatively, the same effect as in the above embodiment can be obtained by measuring the rotation time of the transport motor using a timer.

〔Effect of the invention〕

As explained above, the automatic document feeder according to the present invention always keeps the transported document on the contact glass of the copying machine, even if it feeds various documents of different paper quality and even if it is used for a long period of time. can be transported to the reference exposure position and set reliably without positional deviation.

Therefore, on the copying machine main body side, the original image can always be copied to the appropriate position on the paper.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the basic configuration of the present invention. FIG. 2 is a schematic configuration diagram of an automatic document feeder showing an embodiment of the present invention, and FIG. 3 is a block diagram showing the configuration of its control system. An explanatory diagram showing the positional relationship between the second registration sensor and the exposure reference position on the contact glass, FIG. 5 is a flow diagram showing the pulse counting process by the CPU 27 in FIG. 3, and FIG. 6 is the same <document conveyance by the CPU 27 Flow diagram showing job processing; Figures 7 to 11 are flow diagrams of each job in the routine of Figure 6; Figures 12 (a) to (d) are operation of each part to explain the operation of this embodiment. FIG. 1... Automatic document feeder (ADF) 6... Tip/size sensor 7... First registration sensor 8... Second registration sensor 12... Conveyance belt 17... Contact glass 20...Control unit 21...Paper feed motor 22.
...Transport motor 33...Rotary encoder 27
...Microcomputer (CPU) M...Reference position 314 Figure 5 Figure 6 317 Figure 9 Cause 1111 Figure 10

Claims (1)

[Scope of Claims] 1. Documents on a document table are automatically fed one by one by a paper feeding unit, and a conveyance belt driven by a conveyance motor is used to place a document on a contact glass of a copying machine at a predetermined reference point. In an automatic document feeder, the document is conveyed to an exposure position and stopped, and after exposure is completed, the document is conveyed to a paper discharge section again by the conveyance belt and discharged. A first sensor and a second sensor are arranged to sequentially detect the trailing edge of the document at a predetermined interval in the conveying direction, and while the document is being conveyed by the conveying belt, the trailing edge of the document is detected by the first sensor. means for measuring the number of pulses or rotation time generated in synchronization with the rotation of the transport motor from the time when the second sensor detects the transport motor to the time when the second sensor detects the transport motor; determining a stop timing for stopping the document being transported at the reference exposure position;
An automatic document feeder comprising: means for controlling the stop of the transport motor.