JP3014865B2 - Paper / document tray input detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper / document tray detection device for a copying machine or the like. The present invention relates to a device for detecting an abnormality in paper input to a tray.

[0002]

2. Description of the Related Art As is well known, the system operation of an electrostatic copying machine (hereinafter simply referred to as a copying machine) firstly forms an image of a document by reflecting light reflected from the document on a uniformly charged photosensitive member. To form an electrostatic latent image corresponding to. Next, the electrostatic latent image on the photoreceptor is developed with toner (developer) to form a toner image, and the toner image is transferred onto paper by the electrostatic action of the transfer body, and is heated and fixed to form a document. This is to fix the image.
In the above-mentioned system, the original is placed on a transparent contact glass, illuminates the original from below, and forms an image on a photoconductor through reflected light through an optical system, but when there are a plurality of originals, The copy process is performed using the automatic document feeder.

A typical document flow is as follows. Documents are stacked on a document tray, a single document is separated and fed from the loaded documents, transported to a contact glass surface, and exposed when a fixed position is reached. Begin. When the exposure is completed, the document is discharged and stored in a stack. Next, the cycle of separating and feeding the documents from the tray is repeated, and the copied documents are stacked on the stack. However, in this method, the flow of originals is one direction, and there is a document tray for loading originals that have not been copied and a stack where copying has been completed. Attempts have been made to return the copied document to the tray on which the document is loaded.

As a method of storing an uncopied document and a copied document in one tray, for example, the uncopied document is conveyed to the system from the top of the loaded document, and the copied document is stored in the bottom of the tray. , There is a so-called original reversing method. However, in this original reversing method, since an uncopied original is stacked on the copied original, it is necessary to know whether the returned original has returned to the tray without fail in a stable copying operation. Although it was indispensable, there was no means to detect the document that has been placed in the tray so far. The same applies to the case where a copy-fixed sheet is inserted under the sheet stacked on the sheet tray, so that the original will be described below.

[0005]

In the original reversing method, in which the copied original is returned to the lowermost portion of the uncopied originals stacked on the tray, there is another original on the original to be returned. Document detection sensors, such as actuator-type or optical transmission or reflection-type sensors, are very difficult to detect, and there is no detection method for a document to be inserted. For this reason, in the conventional copier of the original reversing type, there is no means for detecting the occurrence of a paper jam in the tray, and there is a serious drawback such as damaging a plurality of originals fed continuously. Was.

[0006]

Means for Solving the Problems The present invention, in order to solve the above problems, (1) a sheet of such stacked document sequentially transported to the top or Lapu the process that in the tray, the process operation completion Paper / document of equipment having an automatic paper feeder that feeds the later paper to the bottom of the paper stacked in the tray
In the tray input detection device , a pressure sensor disposed on a wall surface of the tray in the sheet return direction, and a tray inside the tray for feeding the sheet returned to the tray in the tray.
A paper feed half-moon roller, and an abnormality detector for detecting whether or not the paper is carried into the tray based on a signal from the pressure sensor; or (2) an original loaded in the tray.
Papers such as manuscripts are sequentially transported from the top to the process,
Paper that has been loaded in the tray
For equipment with an automatic paper feeder that is carried into the bottom of the paper
In the paper / document tray input detection device,
A pressure sensor disposed on the wall in the paper return direction;
When the paper returned to the tray reaches near the tray,
A conveying roller for urging speed, the position sensor for detecting passage of the upstream disposed sheets of the conveying roller, a timer for setting a time until the rotary drive detection after conveying rollers the passage of the sheet at the position sensor when abnormality of transmitting a counter for counting the number of rotations of the conveying rollers when exceeding the set time of the timer, a fault signal when the count value of said counter signal is not output from the pressure sensor exceeds a preset value It has a detector. Hereinafter, a description will be given based on examples of the present invention.

FIG. 1 is a perspective view for explaining the structure of a copying machine to which the present invention is applied. In the drawing, reference numeral 1 denotes an automatic document feeder, 2 denotes a copying machine main body, and 3 denotes a post-processing device. The automatic document feeder 1 sends a document to be copied in response to a start signal to the copying machine main body 2 and copies an image on the surface of the document to the copying machine main body 2.
When the copy of the back side of the document is performed after the exposure of the photoconductor is completed, the front side of the document is automatically inverted and exposed through the optical system after the exposure of the photoconductor is completed. The document is conveyed and discharged, and the uncopied document is automatically conveyed and discharged by the same means. The copying machine body 2
This is a housing portion of an electrophotographic system composed of technical elements for performing charging, exposure, and toner development on the photosensitive member and transferring and fixing the toner image on paper as described above. Post-processing device 3
Is for transporting the copied paper from the paper tray on which the paper is loaded to the copying machine main body 2 and for storing other driving motors and the like.

FIG. 2 is a diagram for explaining a tray paper-in detection device of the automatic document feeder according to the present invention.
4 is a document feed belt, 5 to 15 are document passage detection sensors,
Reference numeral 16 denotes a document lowering roller, reference numerals 17a and 17b denote document feeding half-moon rollers (hereinafter referred to as half-moon rollers), reference numeral 18 denotes a document tray, reference numeral 19 denotes a document presence / absence detection sensor, reference numeral 20 denotes a pressure sensor, reference numeral 21 denotes a document (sheet), Reference numerals 22a and 22b denote exposure surfaces, reference numeral 23 denotes a document rear end guide, reference numeral 24 denotes a guide, reference numeral 25 denotes a transport path, and reference numeral 26 denotes a transport roller.

An operation of conveying a document in the automatic document feeder 1 comprising the above-described components will be described. The plurality of document sheets 21 are stacked in the document tray 18. The document tray 18 is a housing that opens in the document transport direction, has a wall surface in the direction in which the copied document is carried in, and on which a pressure sensor 20 is disposed. Also, when the original sheet 21 is carried into the tray at the bottom of the housing, the original sheet 2 is placed so that the rear end of the original sheet 21 is properly pressed against the pressure sensor 20.
A document trailing end guide 31 and a guide 24 for guiding the document 1 are provided. The original sheet 21 is placed on the original tray 18 first.
Items are loaded below. When the copying operation is started, the original sheet 21 is successively guided to the transport path 25 from the last item of the original sheet 21, that is, the uppermost original sheet 21 by the paper feed belt 4. The document sheet 21 guided to the transport path 25 is guided to the document detection sensor 8 by each transport roller 26, and temporarily stops immediately before the exposure surface 22a. At this time, in the copying machine body 2, paper is fed from a paper tray (not shown), and the paper is conveyed to a position just before the image transfer and temporarily stopped.

Next, the original sheet 21 is conveyed to the exposure surface 22a, and the back surface of the original sheet 21 is exposed. The reflected light from the document is imaged on a photoconductor electrostatically charged by the optical system of the copying system, and an electrostatic latent image is formed on the photoconductor.
This electrostatic latent image is developed with toner (developer) according to an electrophotographic process. The paper fed from the paper tray is conveyed to the image transfer unit so that the toner image is transferred to a predetermined position, and the transfer is performed. The transferred sheet is peeled off from the photoreceptor, transported to a fixing unit (not shown), subjected to fixing by heating and pressing in the fixing unit, and transported to the post-processing device 3.

The document sheet 21 whose back surface has been exposed is conveyed again along the conveyance path 25. When the document sheet 21 passes the document detection sensor 9 and the end of the document sheet 21 is detected by the document detection sensor 10, The transport direction is reversed.
When the inverted original sheet 21 passes through the original detection sensors 11 and 12 in the transport path 25 and is detected by the original detection sensor 13, it is temporarily stopped just before the exposure surface 22b. The original sheet 21 is inverted so that the surface of the original is exposed on the exposure surface 22b, and the surface image of the original sheet 21 is fixed on the sheet in the same manner as when the original sheet 21 is exposed on the exposure surface 22a.

The document sheet 21 whose exposure surface 22b has been exposed is conveyed along a conveyance path 25, passes through the document detection sensors 14 and 15, and is further moved by the document lowering roller 16 to the document sheet 21 stacked on the document tray 18. It is transported to the bottom. The original sheet 21 carried in and returned to the original tray 18 is fed to the original feeding half-moon rollers 17a and 17
b, the paper is fed to the document tray 18 and the end of the document sheet 21 is reliably abutted against the pressure sensor 20 by the document rear end guide 23. When the number of original sheets 21 is a small number, the returned original sheet 21 is guided by the guide 24 and guided to the pressure sensor 20. When the output of the pressure sensor 20 is not obtained even when the original sheet 21 carried in and returned to the original tray 18 is fed by a predetermined distance (time) by the in-tray original feeding half-moon rollers 17a and 17b, The feeding and conveyance of the document sheet 21 are stopped, and an error is displayed.

The pressure sensor 20 detects a pressure change or an impact when the original sheet 21 contacts, and is an electric element, for example, a pressure-sensitive resistance element such as a piezoelectric element or a strain gauge, a mechanical element, For example, an element in which a movable piece, a spring, and a contact are combined is used. Pressure sensor 20
It is necessary to ensure that the end of the conveyed document sheet 21 abuts, so that the mounting horizontal position of the pressure sensor 20 is selected to satisfy this condition.

FIGS. 3A and 3B are diagrams for explaining an embodiment of a tray sheet insertion detecting device according to the present invention.
3A shows a circuit diagram, and FIG. 3B shows a waveform diagram in the circuit. In the drawing, reference numeral 27 denotes a comparison circuit. In FIG. 3A, the pressure sensor 20 is formed by attaching a strain gauge to a deformable member such as a spring plate which is deformed when pressed against the document sheet 21. The strain gauge has a resistance when the document sheet 21 abuts. Change. Returned original sheet 21 to be carried in
Is carried into the pressure sensor 20 by the half-moon rollers 17a and 17b. At this time, the uncopied manuscript sheet 21 already stacked in the manuscript tray 18 has a frictional resistance with the carried back manuscript 21. Ru good force acts, this force on the pressure sensor 20 side. However, returning manuscript sheet 21
Since the kinetic energy due to the mass and the return speed of the original document 21 is greater than the force exerted on the pressure sensor 20 by the non-copy original sheet 21 due to frictional resistance, it is necessary to reliably determine whether the return original sheet 21 returns to the original sheet 18. Can be. Hereinafter, the operation will be described based on FIGS. 3A and 3B.

[0015] via the power source Ec resistor R _1, the pressure sensor 20 is connected. An irregular force due to frictional resistance acting on the uncopied original sheet 21 due to the rotation of the half-moon rollers 17a and 17b is acting on the pressure sensor 20, but at time t _0.
The output A of the pressure sensor 20 suddenly increases due to the force of the return original sheet 21 carried in at step S1. The output A of the pressure sensor 20 is differentiated by the capacitor C and the resistor R _2, and the differentiated output B is input to the inverting input terminal of the comparison circuit 27. On the other hand, a reference voltage E _{0 which} is a judgment level obtained by dividing the power supply EC by the resistors R ₃ and R ₄ is input to the non-inverting input terminal of the comparison circuit 28. The comparison output C is a CPU (Central Processing Unit)
Then, the CPU determines whether or not the original sheet 21 to be conveyed is correctly returned to the original tray 18.

FIG. 4 is a flow chart for explaining another embodiment of the tray-insertion detecting device according to the present invention. Hereinafter, a device for judging whether or not the incoming original has returned to normal (tray-entry detection) will be described. Will be described based on this flowchart. Step 1 : The output of the document passage detection sensor 15 detects that the exposed document sheet conveyed in the conveyance path 25 has passed, and determines that the document sheet 21 enters the document tray 18. step2: the signal of the document passing detection sensor 15 is outputted, a timer is started T ₁ which sets the time A based on this signal. At the same time, the half-moon rollers 17a and 17b are rotated. step3: count time of the timer T ₁ is determined whether or not exceeds the set time A. step4: When the time timer T ₁ exceeds the set time A,
It starts counting the number of rotations of the half-moon roller 17a (or 17b) in the counter C ₁ set number B. The number of rotations of the half-moon roller 17 is an amount that determines the feed amount of the document sheet 21. In addition,
The setting of the set amount B using the counter C is for preventing the original sheet 21 from being excessively fed or insufficient in the original tray 18 depending on the size of the original sheet 21. Of course, the count value of the previous number counter C ₁ is made zero. Step 5 : 1 is added to the count value for each rotation of the half-moon roller 17, and the count value C ₁ +1 is counted. step6: count value of the counter C ₁ is determined whether it is greater than the set value B. step7: If the count value of the counter C ₁ is greater than or equal to the set value B, and determines whether or not there is an output of the pressure sensor 20. If the output is from the pressure sensor 20, no abnormality is recognized, and the process ends. step8 : If there is no output from the pressure sensor 20 even though the original sheet 21 has been moved by a predetermined amount, it is determined that an abnormality has occurred, and all original conveyance in the automatic original feeder 1 is stopped. And perform trouble processing such as display. In the above description, the automatic document transfer apparatus has been described, but the present invention is also applicable to an automatic paper feed apparatus.

[0017]

As is apparent from the above description,
In the reversing method of original sheets, there is no means for reliably detecting that original sheets of paper returned to the tray have been returned to the tray, so that an error such as a paper jam cannot be notified. However, according to the present invention, it is possible to directly detect the paper entry pressure of the document returned to the tray, excluding noise components, so that a highly reliable original document backing method can be used and a small copy Machine can be provided. Furthermore, since the movement amount of the original sheet from the position at the time when the original sheet has completed the predetermined copying process to the tray is quantified and determined by a timer, a counter, and the like, a more reliable tray insertion is performed. A paper detection device can be provided.

[Brief description of the drawings]

FIG. 1 is an overall perspective view for explaining an example of a copying machine to which the present invention is applied.

FIG. 2 is a diagram for explaining a tray paper-in detection device of the automatic document feeder according to the present invention.

FIG. 3 is a diagram for explaining an embodiment of a tray sheet detection device according to the present invention.

FIG. 4 is a flowchart for explaining another embodiment of the tray sheet detection device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Automatic document feeder, 2 ... Copy machine body, 3 ... Post-processing device, 4 ... Document feed belt, 5-15 ... Document passage detection sensor, 16 ... Document lowering roller, 17a, 17b ... Document feed in tray Half moon roller, 18: Document tray, 19: Document presence / absence detection sensor, 20: Pressure sensor, 21: Document (sheet), 22a, 22b: Exposure surface, 23: Document rear end guide, 24: Guide, 25: Transport path, 26: transport roller,
27 ... Comparison circuit.

Claims (2)

(57) [Claims] 1. A conveying the sheet such as a document stacked on the tray in sequence on the top or Lapu the process carries the paper after the process operation completion to the bottom of the sheets stacked in the tray sheet Paper / document tray for equipment with automatic feeder
And a pressure sensor disposed on a wall surface of the tray in the sheet return direction, and a sheet feeder for feeding the sheet returned to the tray in the tray.
A sheet / document tray paper-in detection device, comprising: a half-moon roller; and an abnormality detector for detecting whether or not the paper has been carried into the tray based on a signal from the pressure sensor. 2. The method according to claim 1 , wherein sheets such as originals stacked in a tray are sequentially arranged.
Next, transfer from the top to the process, and after the process operation is completed
Paper to the bottom of the paper stacked in the tray
Paper / document tray for equipment with automatic paper feeder
In the paper input detection device of
Pressure sensor arranged on the wall and returned to the tray
When the paper reaches the vicinity of the tray, the paper is urged to speed up the paper.
And feed roller, a position sensor for detecting passage of the sheet is disposed upstream of the conveying roller, a timer for setting the time until the rotary drive detection after conveying rollers the passage of the sheet at the position sensor, said timer the has a counter for counting the number of rotations of the conveying roller, the abnormality detector that transmits an abnormality signal when the count value of said counter signal is not output from the pressure sensor exceeds the set value when it exceeds the set time paper-document tray of the incoming sheet detection apparatus characterized by.