JP3679764B2 - Document feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a document feeder having a plurality of sensors for detecting a document.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a document feeder mounted on a copying machine is provided with a plurality of sensors and a plurality of motors. In recent years, a sensor provided in a document tray or a document transport path includes a light-emitting element and a light-receiving element arranged so that light from the light-emitting element is reflected from the document and received by the light-receiving element. A sensor in which a light emitting element and a light receiving element are arranged so that the light to the light is blocked by the document has been used. In a sensor of a type in which paper such as an original is interposed between the light emitting element and the light receiving element, paper dust easily accumulates on the light emitting element or the light receiving element. When the amount is insufficient, control is performed to increase the light emission amount of the light emitting element.
[0003]
[Problems to be solved by the invention]
However, while power is supplied to the document feeder, a high current continues to flow to increase the light emission amount of the light emitting element, which may affect the life of the light emitting element. Japanese Patent Application Laid-Open No. 2000-289885 discloses a document feeder provided with a sensor using the above-described light emitting element and light receiving element. When a document is not set on a document tray, the sensor of the document feeder It is shown that the power system power supply is turned off among the logic system power supply including the motor and the power system power supply including the motor. However, since the power supply of the logic system is assumed to be always on, power consumption In this respect, the lifetime problem has not been solved yet.
[0004]
[Means for Solving the Problems]
In view of the above problems, the present invention provides a tray for stacking sheets, first detection means for detecting the presence or absence of a sheet on the tray, and a conveyance path for conveying a sheet fed from the tray. And a second detection means provided in the conveyance path and capable of electrically switching between a state where the presence / absence of a sheet can be detected and a state where the sheet cannot be detected, and a state where the first detection means can detect. Nevertheless, the control means changes the second detection means to an undetectable state, and the control means responds to the fact that the first detection means detects the presence of a document. The sheet feeding device is characterized in that the two detection means are changed to a detectable state .
The present invention also provides a document tray for stacking documents, first detection means for detecting presence / absence of documents on the document tray, and a document conveyance path through which a sheet fed from the document tray is conveyed A second detection unit provided in the document conveyance path and capable of electrically switching between a state in which the presence / absence of the document can be detected and a state in which the document cannot be detected; and a state in which the first detection unit can detect the second detection unit. Despite some, the second have a, and a control means for changing the detection means to the detection impossible state, the control means, in response to said first detection means detects the presence of the document, the An original feeding apparatus characterized in that the second detecting means is changed to a detectable state .
[0005]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of an image forming apparatus of the present invention will be described. FIG. 1 is a diagram illustrating a configuration of an image forming apparatus. The image forming apparatus includes an image forming apparatus main body including an image reader 200 and a printer unit 300, a folding device 500, and a finisher 600. A document feeding device (document feeding device) 100 is mounted on the upper part of the image reader 200.
[0006]
The document feeder 100 feeds the documents set on the document tray 105 one by one in order from the first page, and conveys them onto the platen glass 205 through a curved path. Then, the original is read by moving the original from the left to the right on the scanner unit 206. Thereafter, the read original is discharged to the paper discharge tray 106.
[0007]
The document image read by the image sensor 208 via the lens 207 is subjected to image processing, stored in the hard disk 413 (see FIG. 3), and sent to the exposure control unit 305 via the printer control unit 301. The exposure control unit 305 outputs laser light corresponding to the image signal. When this laser light is irradiated onto the photosensitive drum 306, an electrostatic latent image is formed on the photosensitive drum 306. The electrostatic latent image on the photosensitive drum 306 is developed by the developing unit 307, and the developer on the photosensitive drum 306 is applied to the sheet fed from any of the cassettes 308 and 309, the manual sheet feeding unit 310, and the duplex conveyance path 311. Transferred by the transfer unit 312.
[0008]
When the developer-transferred sheet is guided to the fixing unit 313, the developer is fixed. The sheet that has passed through the fixing unit 313 is once guided from the path 315 to the path 314 by a flapper (not shown), and after the trailing end of the sheet has passed through the path 315, the sheet is switched back and guided from the path 316 to the discharge roller 317. . As a result, the surface onto which the developer has been transferred can be turned downward (face down) and discharged from the printer unit 300 by the discharge roller 317. This is called reverse paper discharge.
[0009]
Thus, by discharging face down, it is possible to form an image in the correct page order from the first page, such as when using the document feeder 100 or printing an image output from an external computer. .
[0010]
When an image is formed on the hard sheet such as an OHP sheet from the manual sheet feeding unit 310, the surface onto which the developer has been transferred is faced up (face-up) without being guided to the pass 315, and is discharged from the discharge roller 317. Discharge.
[0011]
In addition, when forming an image on both sides of a sheet, the sheet is guided from the fixing unit 313 to pass 315 and pass 314, the sheet is switched back immediately after the rear end of the sheet passes through the path 315, and is conveyed by a flapper (not shown). Guide to path 311. The electrostatic latent image is transferred again to the sheet guided to the duplex conveyance path 311 by the transfer unit 312 and subjected to fixing processing by the fixing unit 313.
[0012]
The sheet discharged from the paper discharge roller 317 is sent to the folding device 500. The folding device 500 performs a process of folding the sheet into Z-folds. When the folding process is specified for the A3 size sheet or the B4 size sheet, the folding apparatus 500 performs the folding process, and then the sheet is sent to the finisher 600. The other size sheets are sent to the finisher 600 as they are. The finisher 600 performs bookbinding processing, binding processing, punching processing, and the like. In addition, an inserter 700 is provided on the upper portion of the finisher 600 and feeds a cover sheet, a slip sheet, and the like to the finisher 600.
[0013]
FIG. 2 is a block diagram illustrating the configuration of the control unit of the image forming apparatus. A control unit that controls the entire image forming apparatus is configured around a CPU circuit unit 400. The CPU circuit unit 400 is provided with a CPU 401, a ROM 402, a RAM 403, and the like.
[0014]
The CPU circuit unit 400 is stored in the ROM 402 and is executed by the CPU 401 and the document feeder control unit 101 that controls the document feeder 100 according to the settings of the operation unit 102 and the image reader that controls the image reader 200. Unit 201, image signal control unit 405, printer control unit 301 that controls printer unit 300, folding device control unit 501 that controls folding device 500, finisher control unit 601 that controls finisher 600, and external interface (I / F) 406 To control.
[0015]
The RAM 403 is used as an area for temporarily storing control data and a work area for computations associated with control. An external I / F 406 is an interface with the external computer 407, and print data from the external computer 407 is developed into an image and output to the image signal control unit 405.
[0016]
The image reader control 201 outputs an image read by the image sensor 208 to the image signal control unit 405, and the image data output from the image signal control unit 405 to the printer control unit 301 is input to the exposure control unit 305.
[0017]
FIG. 3 is a block diagram illustrating a configuration of the image signal control unit 405. The image signal control unit 405 includes an image processing unit 410, a line memory 411, a page memory 412, and a hard disk 413. The image processing unit 410 performs image correction processing and editing processing according to the settings in the operation unit 102. The line memory 411 performs a mirror image process for exchanging images in the main scanning direction. The image in the line memory 411 is output to the printer control unit 301 via the page memory 412. Further, the hard disk 413 is used as necessary, for example, when the order of pages to be printed is changed as will be described later, and stores an image in the page memory 412.
[0018]
4, 5, and 6 are diagrams illustrating the configuration of the document feeder 100. The swinging motor 83 is driven to lower the paper feed roller 5 on the uppermost paper surface of the document bundle set on the document tray 105 with the document surface facing upward (face up). Then, by driving the separation motor 80, the paper feed roller 5 and the separation conveyance roller 8 are driven and conveyed one by one from the uppermost sheet of the document bundle to the reading position of the platen glass 205.
[0019]
From the document tray 105 to the platen glass 205, document conveyance paths (A), (B), and (C) for guiding the document onto the platen glass 205 are configured. The document conveyance paths (A), (B), and (C) are bent (curved downward) and connected to the document conveyance path (D) on the platen glass 205. The document conveyance path (A) is a conveyance path through which the document separated by the separation unit is conveyed in the downstream direction by the separation conveyance roller 8. Reversal conveyance paths (H), (F), and (I) extend from the document conveyance path (B). The reverse conveyance paths (H), (F), and (I) are used to reverse the front and back before conveying the document to the platen glass 205. The document reversed in the reversal conveyance paths (H), (F), and (I) is switched back and conveyed to and placed on the platen glass 205 through the document supply / discharge path (E).
[0020]
In the single-sided original mode, the original conveying paths (B), (C), and (D) and the original are conveyed. In the double-sided mode, the original conveying path (B) to the original reversing path (H) (F) (I) And (E) and (D). Then, the back side of the document set on the document tray 105 is in a readable state. The pre-inversion flapper 22 is switched by driving the pre-inversion flapper solenoid 88 to be guided to the conveyance path (C) or the conveyance path (H) after the document conveyance path (B). Further, a document reversing path (G) is branched from the reversing conveyance path (F) so that it can merge with the document conveying path (B). If the transport paths (E), (F), (G), and (C) are used, the document on the platen glass 205 can be switched back and turned upside down, and returned to the platen glass 205 again.
[0021]
In the double-sided original mode, when the front side is reversed and the front side is read after reading the back side, the transport paths (E), (F), (G), and (C) are guided. The reverse flapper 21 is switched by driving the reverse flapper solenoid 87 to be guided to the transport path (I) or the transport path (G) after the transport path (F). The original on the platen glass 205 is discharged to the paper discharge tray 106 through the original conveyance path (D) and the original discharge path (J) on the platen glass 205 after the image reading is completed. In order to guide from the conveyance path (D) on the platen glass 205 to the document discharge path (J), the document must be scooped up from the platen glass 205. Therefore, the discharge flapper solenoid 89 is driven to lower the discharge flapper 23 downward.
[0022]
On the right side of the document feeder 100, an openable manual document tray 14 is provided. A document (one document) set on the manual document tray 14 can be fed to the platen glass 205 through the manual conveyance path (K). The original on the platen glass 205 is discharged to the paper discharge tray 106 through the original conveyance path (D) and the original discharge path (J) on the platen glass 205 after the image reading is completed.
[0023]
FIG. 7 is a block diagram showing a circuit configuration of the document feeder 100. The document feeder 100 includes a CPU 90, a RAM 91, a ROM 92 in which control sequence software is stored, and a communication IC 93 for controlling data communication with the image forming apparatus 300. The document feeder 100 performs all operations based on data from the image forming apparatus via the communication IC 93 and constantly transmits the state of the document feeder 100. The input / output ports of the CPU 90 are connected to various load drive circuits and sensor signals.
[0024]
In the present embodiment, the separation motor 80 (DC brush motor) is driven and controlled by a driver (not shown) and a controller (not shown). The controller receives a reference clock, an on / off signal, and the like as a reference for the motor rotation speed from the CPU 90.
[0025]
The reverse motor 81 (stepping motor) and the belt motor 82 (stepping motor) are driven with a constant current by a stepping motor driver (not shown). Each driver receives a phase excitation signal and a motor current control signal from the CPU 90.
[0026]
The swing motor 83 (stepping motor) is driven at a constant voltage by a driver (not shown). The paper discharge motor 84 (DC brush motor) is driven and controlled by a driver (not shown) and an FG servo controller (not shown).
[0027]
The stopper solenoidoid 85, the separation clutch 86, the reverse flapper solenoid 87, the pre-reverse flapper solenoid 88, and the paper discharge flapper solenoid 89 are each driven by a driver (not shown). All the drivers are controlled in operation by a signal connected to the input / output port of the CPU 90.
[0028]
Further, the separation sensor 30, the skew detection sensor 31, the pre-registration sensor 32, the post-registration sensor 33, the reverse sensor 34, the paper discharge sensor 36, the original set sensor 37, the original rear end detection sensor 38, the final paper detection sensor 39, manual feed Various sensors such as a document set sensor 40, a paper feed roller home sensor 42, a document width detection sensor 44, a cover opening / closing detection sensor 45, and a DF opening / closing detection sensor 46 are connected to an input port of the CPU 90, It is used to monitor the behavior of the machine and the behavior of the movable load. As shown in FIG. 4, the document set sensor 37 is provided on the document tray 105 and detects whether or not a document is placed on the document tray 105. The manual document set sensor 40 is provided in the manual document tray 14 and detects whether or not a document is placed on the manual document tray 14. Further, the separation sensor 30, the skew detection sensor 31, the pre-registration sensor 32, the post-registration sensor 33, the reverse sensor 34, and the paper discharge sensor 36 are provided in the document conveyance path.
[0029]
FIG. 8 is a diagram illustrating a sensor circuit configuration of the document feeder 100. Separation sensor 30, skew detection sensor 31, pre-registration sensor 32, post-registration sensor 33, reverse sensor 34, paper discharge sensor 36, document set sensor 37, document trailing edge detection sensor 38, final paper detection sensor 39, manual document set Various sensors such as a sensor 40, a paper feed roller home sensor 42, a document width detection sensor 44, a cover open / close detection sensor 45, and a DF open / close detection sensor 46 are configured by a circuit shown in FIG. Each sensor has an LED 301 (light emitting element) and a phototransistor 302 (light receiving element). The ON / OFF of the transistor 303 is controlled by the output of the sensor ON / OFF signal connected to the output port of the CPU 90, and it is configured to be able to switch whether or not the light emitting element emits light. When is OFF, the LED 301 (light emitting element) is not emitting light, and at this time, the CPU 90 ignores the input signal from the sensor.
[0030]
However, an ON signal is always output to the document set sensor 37 and the manual document set sensor 40, and the light emitting element always emits light. Although the CPU 90 outputs ON signals to the document set sensor 37 and the manual document set sensor 40, at least the separation sensor 30, the skew detection sensor 31, the pre-registration sensor 32, the post-registration sensor 33, and the reverse sensor 34. Then, the ON / OFF signal is turned off to the paper discharge sensor 36 to make it impossible to detect. If it is determined from the sensor output signal of the document setting sensor 37 or the manual document setting sensor 40 that the document is set, the CPU 90 at least separates the separation sensor 30, the skew detection sensor 31, the pre-registration sensor 32, and the post-registration sensor 33. Then, the ON / OFF signals of the reversing sensor 34 and the paper discharge sensor 36 are turned ON, and all the sensors other than the above are switched from the undetectable state to the detectable state. The ON / OFF signal is kept on even while the operation is not started and the original is still set.
[0031]
When the power of the document feeder 100 is turned on, the drive unit (the separation motor 80, the reverse motor 81, the belt motor 82, the swing motor 83 in the document feeder 100, the paper discharge motor 84, the stopper solenoid 85, The separation clutch 86, the reverse flapper solenoid 87, the pre-reverse flapper solenoid 88, and the paper discharge flapper solenoid 89) are initialized. When the ON / OFF signal is switched ON, the drive unit in the document feeder 100 is turned on. Since initialization is not performed, noise can be prevented and operation can be performed in a short time. After the image reading operation of the document set on the document tray 105 or the manual document tray 14 is started, at least when all the documents set on each tray are discharged to the discharge tray 106, at least The ON / OFF signals of the separation sensor 30, the skew detection sensor 31, the pre-registration sensor 32, the post-registration sensor 33, the reverse sensor 34, and the paper discharge sensor 36 are turned off to stop the light emission of the sensor light emitting element (undetectable state) ).
[0032]
In addition, after the document is set on the tray, the document setting sensor 37 or the manual document setting sensor 40 is turned off and no paper is detected without performing the image reading operation. At least the separation sensor 30, the skew detection sensor 31, the pre-registration sensor 32, the post-registration sensor 33, the reverse sensor 34, and the paper discharge sensor 36 are turned off to stop the light emission of the sensor light emitting element (undetectable state) ).
[0033]
As described above, at least the separation sensor 30, the skew detection sensor 31, the pre-registration sensor 32, the post-registration sensor 33, the reverse sensor 34, and the paper discharge sensor 36 are turned off to stop the light emission of the sensor light emitting element. By making the state incapable of detection, the lifetime of the sensor can be extended and the power consumption can be reduced. Note that the light emission amount of the sensor light emitting element is reduced by replacing the above-mentioned ON / OFF signal with a variable analog value and setting it to a value lower than the analog value corresponding to the above-mentioned ON when the above-mentioned condition is to be turned OFF. Thus, the life of the sensor can be extended and the power consumption can be reduced.
[0034]
When the image reader 200 reads a document image set on the platen glass 205 instead of the document conveyed from the document feeder 100 (book mode), the document on the platen glass 205 is removed after the reading is completed. It may be determined whether the document feeder 100 is opened or closed. Since the above determination cannot be made when no document is set on the document feeder 100 and the open / close detection sensor 46 cannot detect the open / close state, the open / close detection sensor 46 is the same as the document set sensor 37. At all times, the sensor light emitting element is caused to emit light so that the open / closed state can be detected. The detected opening / closing state of the document feeder is always notified to the image forming apparatus 300 via the communication IC 93.
[0035]
As another embodiment, not only the document set sensor 37 but also the document trailing edge detection sensor 38 and the final document detection sensor 39 provided on the document tray 105 are configured to always detect the presence or absence of a document. When such a sensor detects the presence of a document, an ON / OFF signal may be turned on to switch all sensors to a detectable state. Alternatively, when all the sensors detect that there is no document, the ON / OFF signal may be turned off to switch the other sensors to an undetectable state.
[0036]
【The invention's effect】
As described above, according to the first aspect of the present invention, the tray for stacking sheets, the first detecting means for detecting the presence or absence of the sheet on the tray, and the sheet fed from the tray Is detected by a first detection unit , a second detection unit that is provided in the conveyance path and that can be electrically switched between a state in which the presence or absence of a sheet can be detected and a state in which the sheet cannot be detected. despite the ready, and a control means for changing the second detecting means to the detection impossible state, it was closed, the first detecting means and the control means in response to the detected the presence sheet Since the second detection means is changed to a detectable state, the life of the second detection means can be extended.
[0037]
According to a fifth aspect of the present invention, there is provided a document tray for stacking documents, first detection means for detecting presence or absence of documents on the document tray, and sheets fed from the document tray. A document conveyance path to be conveyed; a second detection means provided in the document conveyance path; and a first detection means capable of electrically switching between a state where the presence or absence of a document can be detected and a state where the document cannot be detected; The second detecting means is changed to a non-detectable state in spite of being in a detectable state, and the control means responds to the fact that the first detecting means detects the presence of a document. Since the second detection means is changed to a detectable state, the life of the second detection means can be extended.
[0038]
According to the fifth aspect of the present invention, it is possible to detect whether or not a document is placed on the tray even when the second detection means is in a state where it cannot be detected. According to the fifth aspect of the present invention, the second detection means provided in the conveyance path can be set in a non-detectable state as necessary. According to the fifth aspect of the present invention, the life of the second detecting means is extended by switching the second detecting means from the undetectable state to the detectable state when the document is placed on the document tray. be able to. According to the sixth aspect of the present invention, the second detection means is switched from the detectable state to the undetectable state when the document is removed after the document is placed on the document tray. The life of the two detection means can be extended. According to the seventh aspect of the present invention, the life of the second detection means can be extended by switching the second detection means from the detectable state to the undetectable state after image reading of all the originals. it can. According to the eighth aspect of the invention, the life of the light emitting element of the second detecting means can be extended by stopping the light emission of the light emitting element of the second detecting means. According to the ninth aspect of the present invention, the lifetime of the light emitting element of the second detecting means can be extended by reducing the light emission amount of the light emitting element of the second detecting means. According to the tenth aspect of the present invention, it is possible to always monitor the opening and closing of the document feeder. According to the eleventh aspect of the present invention, it is possible to provide a document feeder having a simple and inexpensive configuration. According to the invention described in claim 12, it is possible to provide a document feeder having a simple and inexpensive configuration. According to a thirteenth aspect of the present invention, since the control unit performs control to change the second detection means to a detectable state without performing initialization of the drive unit, noise due to initialization of the drive unit is prevented. And can be operated in a short time.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of an image forming apparatus.
FIG. 2 is a block diagram illustrating a configuration of a control unit of the image forming apparatus.
3 is a block diagram showing a configuration of an image signal control unit 405. FIG.
FIG. 4 is a diagram illustrating a sensor configuration of the document feeder.
FIG. 5 is a diagram illustrating a conveyance path configuration of the document feeder.
FIG. 6 is a diagram illustrating a drive system configuration of the document feeder.
FIG. 7 is a block diagram of a document feeder.
FIG. 8 is a sensor circuit diagram of the document feeder.
[Explanation of symbols]
37 Document setting sensor 38 Document trailing edge detection sensor 39 Final document detection sensor 40 Manual document sensor 105 Document tray

Claims (14)

A tray for loading sheets;
First detecting means for detecting the presence or absence of a sheet on the tray;
A conveyance path through which a sheet fed from the tray is conveyed;
A second detection means provided in the conveyance path and capable of electrically switching between a state where the presence or absence of a sheet can be detected and a state where the sheet cannot be detected;
It said first detecting means despite the possible detection state, have a, and a control means for changing said second detecting means to the detection impossible state,
The sheet feeding apparatus according to claim 1, wherein the control unit changes the second detection unit to a detectable state in response to the first detection unit detecting the presence of a sheet. A discharge tray for stacking sheets fed from the tray and transported through the transport path;
After the second detection unit is changed to a detectable state, the control unit detects the second sheet when all the sheets placed on the tray are discharged to the discharge tray. 2. A sheet feeding apparatus according to claim 1, wherein said detecting means is changed to a state in which the presence or absence of a sheet cannot be detected. The second detection means includes a light emitting element and a light receiving element,
3. The sheet feeding apparatus according to claim 1, wherein the control unit stops light emission of the light emitting element when the presence or absence of the sheet is changed to an undetectable state. 4. The second detection means includes a light emitting element and a light receiving element,
3. The sheet feeding apparatus according to claim 1, wherein the control unit reduces the light emission amount of the light emitting element when changing the presence / absence of the sheet to an undetectable state. 4. A document tray for loading documents,
First detecting means for detecting the presence or absence of a document on the document tray;
A document conveyance path through which a sheet fed from the document tray is conveyed;
A second detection means provided in the document conveyance path, and capable of electrically switching between a state where the presence or absence of a document can be detected and a state where the document cannot be detected;
It said first detecting means despite the possible detection state, have a, and a control means for changing said second detecting means to the detection impossible state,
The document feeding device according to claim 1, wherein the control unit changes the second detection unit to a detectable state in response to the first detection unit detecting the presence of a document. A paper discharge tray for loading originals fed from the original tray and subjected to image reading;
After the second detection unit is changed to a detectable state, the control unit detects the second detection in response to the first detection unit detecting the absence of a document before starting the image reading operation. 6. The document feeder according to claim 5, wherein the means is changed to a state in which the presence or absence of the document cannot be detected. A paper discharge tray for loading originals fed from the original tray and subjected to image reading;
After the second detection means is changed to a detectable state, the control means responds to the fact that all the documents placed on the document tray are discharged to the discharge tray. 6. A document feeding apparatus according to claim 5, wherein said detecting means is changed to a state in which the presence or absence of a document cannot be detected. The second detection means includes a light emitting element and a light receiving element,
8. The document feeder according to claim 5 , wherein the control unit stops light emission of the light emitting element when the presence or absence of the document is changed to an undetectable state. 9. The second detection means includes a light emitting element and a light receiving element,
8. The document feeder according to claim 5 , wherein the control unit reduces the light emission amount of the light emitting element when changing the presence / absence of a document to an undetectable state. 9. A third detecting means for detecting an open / closed state of the document feeder;
10. The third detection unit according to any one of claims 5 to 9, wherein the third detection unit always detects an open / closed state and notifies a detection result to the image forming apparatus regardless of the detection of the original by the first detection unit. The document feeder according to claim 1 . 11. The document feeder according to claim 5 , wherein the first detection unit includes a light emitting element and a light receiving element.   12. The document feeder according to claim 11, wherein the light emitting element is an LED, and the light receiving element is a phototransistor. A roller for conveying a sheet conveyed in the conveyance path;
A drive unit that is controlled by the control unit and drives the roller,
In a state where the first detection unit can be detected, the control unit changes the second detection unit from an undetectable state to a detectable state without performing initialization of the drive unit. The sheet feeding apparatus according to any one of claims 1 to 4. The sheet feeding apparatus according to claim 13, wherein the control unit initializes the driving unit when power is turned on.

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